CA2099780C - Computer controlled smart phacoemulsification method and apparatus - Google Patents
Computer controlled smart phacoemulsification method and apparatusInfo
- Publication number
- CA2099780C CA2099780C CA002099780A CA2099780A CA2099780C CA 2099780 C CA2099780 C CA 2099780C CA 002099780 A CA002099780 A CA 002099780A CA 2099780 A CA2099780 A CA 2099780A CA 2099780 C CA2099780 C CA 2099780C
- Authority
- CA
- Canada
- Prior art keywords
- aspiration
- transducer
- amount
- load
- power
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
- A61B17/20—Surgical instruments, devices or methods, e.g. tourniquets for vaccinating or cleaning the skin previous to the vaccination
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F9/00—Methods or devices for treatment of the eyes; Devices for putting-in contact lenses; Devices to correct squinting; Apparatus to guide the blind; Protective devices for the eyes, carried on the body or in the hand
- A61F9/007—Methods or devices for eye surgery
- A61F9/00736—Instruments for removal of intra-ocular material or intra-ocular injection, e.g. cataract instruments
- A61F9/00745—Instruments for removal of intra-ocular material or intra-ocular injection, e.g. cataract instruments using mechanical vibrations, e.g. ultrasonic
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M1/00—Suction or pumping devices for medical purposes; Devices for carrying-off, for treatment of, or for carrying-over, body-liquids; Drainage systems
- A61M1/71—Suction drainage systems
- A61M1/74—Suction control
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
- A61B2017/00017—Electrical control of surgical instruments
- A61B2017/00022—Sensing or detecting at the treatment site
- A61B2017/00026—Conductivity or impedance, e.g. of tissue
- A61B2017/0003—Conductivity or impedance, e.g. of tissue of parts of the instruments
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
- A61B2017/00017—Electrical control of surgical instruments
- A61B2017/00022—Sensing or detecting at the treatment site
- A61B2017/00106—Sensing or detecting at the treatment site ultrasonic
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
- A61B2017/00017—Electrical control of surgical instruments
- A61B2017/00115—Electrical control of surgical instruments with audible or visual output
- A61B2017/00128—Electrical control of surgical instruments with audible or visual output related to intensity or progress of surgical action
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B90/00—Instruments, implements or accessories specially adapted for surgery or diagnosis and not covered by any of the groups A61B1/00 - A61B50/00, e.g. for luxation treatment or for protecting wound edges
- A61B90/06—Measuring instruments not otherwise provided for
- A61B2090/064—Measuring instruments not otherwise provided for for measuring force, pressure or mechanical tension
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M1/00—Suction or pumping devices for medical purposes; Devices for carrying-off, for treatment of, or for carrying-over, body-liquids; Drainage systems
- A61M1/71—Suction drainage systems
- A61M1/77—Suction-irrigation systems
Abstract
A method and apparatus for operating on the human eye detects changes in load, m ore specifically, mechanical impedance, of the transducer (300) and controls aspiration based on the load cha nges. A change from a lower load to a higher load indicates that harder tissue is being encountered and accordingly causes aspirat ion amount to increase. Conversely, a change from a higher load to a lower load indicates that aspiration amount should be quickly decreased since the tissue which is being encountered is softer. One way to detect the impedance is by a sensor (1008), e. g., a piezoelectric element coupled to the operating needle detecting the movement thereof.
Description
WO ~2/11814 PCI'/US92/00013 2 a ~ 0 COMP~TER CONTROI,LEI) SM21~RT P~IACOE:HUI.SIFICATION
~:THOD AND APPARAT~JS
FI~ n OF TEIE lNv~ oN:
The present invention relates to a computer controlled "smart" phacoemulsification apparatus, and more specifically ~o one which controls power delivery ~o the needle of the transducer and also controls an amount of aspiration based on a load on the tip of the transducer.
BACRGROUND AND SUMM~RY OF THE lNv~NllON~
Eye surgery is a complicated and delicate process. One common eye surgery is cataract extraction. There are currently several methods of acceptable cataract extraction, including phacoemulsification. Phacoemulsification is not in itself new, but as currently done has many problems.
Phacoemulsification involves the ;
generation of an ultrasonic signal which is a series ;
of cyclical mechanical vibrations in a frequency range beyond that detectable by normal human hearing. The ultrasonic signal is generated by a transducer that is driven by an electrical signal in a fre~uency range between 20 and 100 kilohertz in equipment pr~sently available for this application.
Typically the transducer mechanism includes either piezoelectric or magnetostrictive elements.
The energy resulting from the ultrasonic signal is coupled ~o the human lens by a needle attached to the transducer. Typically the needle is made from an inert alloy o~ titanium or stainless ste~l. Once coupled to the human lens, the ultrasonic energy fragments and emulsified the cataract. Once this nuclear material is fragmented, - . -.,.;.
' ',' .
.. , ,,, ,. ,,,. ", , ., . . . . ~ , . , ... ... ~, .. .
WO9~/11814 PCT/US92/00013 h~ O ~ 9 7 80' however, it must be removed from th~ eye. In order to do this, the ultrasonic needle is hollow, and an aspiration system is oonnected to the hollow area in order to remove the fragmented particles. A
balanced salt solution is also injected in order to maintain the stability or pressure, a.nd this infusion occurs around the vibrating titanium needle through a sleeve.
An example of such a phacoemulsification unit is shown in U.S. Patent 4,223,676. Current phacoemulsification surgery allows the surgeon to choose either a ~ixed ph~co mode in which the power setting to the transducer is fixed, or a linear mocle :
in which the phaco power can be changed by the power pedal. In the fixed mode, the phaco unit is either on or off depending on whether the pedal is depressed or not. The value of power setting is preset. In the linear mode, the further depression of the pedal varies the amount of power to the transducer and thereby the ultrasonic energy. The aspiration during this operation is preset. A third mode of phacoemulsifica~ion which has been recently introduced keep~ the phaco power fixed and varies the aspiration depending on the foot pedal.
The inventor of the present invention has recognized a problem which exists in these prior operations. In order to fully understand this, one must consider the structure of the lens of the human eye. Figure 1 shows diagrammatically a human lens which has an outer, fine, transparent tissue or capsule shown as layer lO0. ~nterior to this is a : . sof~ material known as the cortex 102, which surrounds the transition layers 104. The nucleus of ......
WO92/11814 PCT/~S92/00013 2~7~a the lens is a hard, compressed lens mal:erial shown as 106. The inventor o~ ~he present invention has first noted that in these soft outer cortical layers, little aspiration is required, but more aspiration is required in ~he harder transitional layers and even more in the hardest nucleus layer.
However, pos~erior ~o the hardest nucleaus layer is a less hard transitional layer followed by A soft cortex. A majority of the complications during eye surgery are caused not by the amount of phacoemulsification, but by overaspiration in conjunction with the emulsification causing a "punch through" through the posterior lens capsule. This is particularly dangerous since the center of the lens needs more energy (aspiriation and emulsification) than the outer soft cortical layer, i "
and therefore therç is more possibility of punch-through at this higher energy level and high aspiration level.
Eye surgery involv~s ~orming an opening in the front of the capsule, and locating the phaco needle first into the so~t cortex. ~t this time the needle will experi~nce a minimal load in th~ soft cortex. As the needle goes further into the nucleus which is progressively harcler, the mechanical load i increases. A~ter passing through the nucleus, the process reverses, and the mechanical load will quickly decrease. It is at: ~his point that the inventor of the present invention has Pound that the control of aspiration becomes critical. O~er-aspiration at this time can cause the posterior capsule to be ruptured. However, determination o~ -the relative hardness of these layers has previ~usly WO92/llgl4 PCT/US92/00013 ~0~7~-~
been left to the observation skills and manual skills of the surgeon. However, the surgeon has many other things on his mind and also simply may not be able to react fast enough in order to properly change the aspiration amount.
The inventor of the present invention has recognized that a hard nucleus consumes more energy than a soft nucleus, thereby changing the impedance, ~:
and more specifically the mechanical impedance, introduced to the ultrasonic tip. According to the present invention, this difference is fed back to a :
microprocessor in order to modify the aspiration system dependent on the hardness of the material being operated upon. This reduces the problem of "punch through" because it allows automatic checking of the hardness of the material and automatic adjustment of the aspiration delivery in a way which is ~aster than could ever be done using human .
reflexes. Such a syst~m has never been described in the prior art. : .
One way in which this is done i5 by detecting mechanical impedance of the tissue, using, for example, a sensor to de~tect response to a stimulus.
One general feature of the present -~
invention is the recoynition by the inventor of the : .
present invention that soft tissue requixes a low .
stroke or low velocity and tha~ hard tissue requires a high stroke and high velocity. The mechanical impedance of any material including the human eye is a function of the density p and sound velocity C. It ~ usually has a resistive component ~ and a reactive component X,. Compliant or deformable tissue presents primarily a resistive impedance to the : ,.
WO92/11814 PCT/US~2/00013 2~9~78~
driving force. Non-compliant or non-deformable tissues are primarily a reactive impedance. In other words, soft tissue will be more resistive and hard tissue will be more reactive.
One approach to detecting mechanical impedance from a piezoelectric hand piece is to read the driving voltage and current. Here not only magnitude but also phase will be monitored where zero phase difference will indicate a resistive load on soft tissue. A large phase difference would indicate a reactive load or hard tissue. Another approach would include determining the resonant frequency of the loaded hand piece in relation to a reference, which can be the resonant frequency of the unloaded hand piece. If the transducer is ~;
formed as a half wavelength straight bar, its resonant frequency will not change for purely resistive loads and can be determined according to the equation .: .. .
tan (2~f x) = 0 :
where f is the operational fre~uency, c is the speed of sound in the bar, and x is the length of the barO
For a purely reactive load, the resonan~ frequency is determined by the equation tan (2~f x ) =
c Zo ..
where XL is the reac~ive load and Z0 is the characteristic impedance o~ the bar. If the .
' :
.. :.. , ., . : ~ ,: . . , - - - -. .. ~; , ,, ~ 1,'. . . .,.. - . - '; . ,; . ~
rl ~ ~
transducer is made as a step horn type to provide amplification of the displacement, the~ resonant frequency will change for either resiC;tive or reactive loads. A typical step horn device is shown in Figure 14 with its two parts 1050 and 1052. The lengths X of the parts 1050 and 1052 are equal to one another but their areas differ by a factor of N>10.
For a device Qf this type, the resonant frequency is determined according to the equation tan (2~f x) = R
c 20 where X is the length shown in Figure 14 and Z0 is the characteristic impedance of the transducer material as shown in Figure 15. ~rhe part 1052 has the impP~nce zo while the part 1050 has the characteristic imre~nce N x Z0. For purely reactive loads the resonant frequency can be determined from the equation , (tan 2~f x) = (XL)' c Z.
These equations are general and exemplary and different needle/transducer arrangements could use different equations.
Many attempts have been made in the prior art in order to atkempt to automate operation processes. U.S. Patent 4,223,676 is one such attempt and defines one type of ultrasonic aspirator of the type previously described above. Column 8 of this patent recognizes that frequency fluctuates ..
during the course of an operation, and in order to :
attempt to maintain the amount of power delivery as . ',:
; ' ~'. .
, , , ~ - ~ , , , . - , , . .. . . ~ .
2Q~s~sa constant, this patent tezches monitoring actual and expected parameters of the system. The difference between these two parameters is fed back in a .
feedback loop to control the stroke level of the s vibrator. Therefore, while the power of the system :-is controlled, there is no teaching of controlling the amount of aspiration, and as such the problem of "punch through" would still remain in this system. ..
Similarly, U.S. Patent 3, 9~4, 487 teaches a structure which monitors the impedance of the electric cutting apparatus, and feeds back this :~
impedance to determine the amount of power to be provided. This device does not teach controlling the amount of aspiration, and there~ore would not alleviate the problem of "punch through". . ;
Simllarly, U.S. Patent 4, 126, 137 teaches sensing of the impedance of the tissues to set the amount of drive to an electro-surgical unit.
U.S. Patent 4,024,866 relates to a device which teaches controlling the amount of suction in a suction conduit for eye surgery. Column 7, lines 24 ++ teach that an upper limit is placed on the amount of suction to prevent an excessive amount of suction. While this might provide an upper limit, it does not heIp the user to obtain better control and better feedback within the system BRIEF DESCRIPTION OF THE DRAWIN~S~
These and other aspects of the invention ~:
: will now be described i~ detail with reference to the accompanying drawings, in which: .
Figure l shows a schematic view of the human eye;
' ' .
.~
' ' ' :
WO92/11814 PC~/US92/00013 2a~978~
Figure 2 shows a representati~e amount of aspiration required in a travPrsal through the eye;
Figure 3 shows a blocked diagram representation of a first embodiment of the present i~vention;
Figure 4 show~ a flow chart of operation . : .
of this first embodiment;
Figure 5 shows a blocked diagram representation of a second embodiment of the present invention which uses a speech enunciator to aid the surgeon with his operation;
Figure 6 shows a flow chart of operation . of the second embodiment.
Figure 7 shows a structure of the third embodiment of the present invention; and Figure 8 shows a flow chart of this operation. . -Figures 9 and 10 show characteristic ~ ;.
curves for characteristics i~ Almond, and a peanut "M & M(TM)", respectively;
Figure 11 shows~a block di~gram of a fourth embodiment of the invention; ~' Figure 12 shows a flowchart of operation :. :
of this fourth embodime~t; and Pigure 13 shows a block diagram of a fifth embodiment of the invention; and . :
Figure 14 shows a typical phaco needle. ~
:
1~ 01~ 0~ q~HE ~ ;rr;n~13D ~D1...L~. . 5:
A presently preferred embodiment will now be described ln detail wi~h respect ~o ~he accompanying drawings. Figure 3 shows a first ,~ '..
. ~ .
7 ~ ~
embodiment of the invention. Transducer 300 is shown attached to phaco needle 302 which is adapted to come into contact with a lens 304 o~ the human eye. The power supplied by power supply 306 to the transducer 300, and at the same ~ime the voltage and ;.
current is monitored by monitor 30~. Monitor 308 monitors the voltage and current, and produces :
analog si~nals which are converted by analog to digital converter into digital si~nals, and are input to microprocessor 312. Microprocessor 312 can be any commercially available type. An aspiration control 314 is also input to microprocessor as is a power supply control 316. These devices can be either dial-type potentiometers or the usual surgeon's foot pedal, and produce a command signal indicative of the amount o~ aspiration and power respectively desired. Microprocessor 312 produces analog signals which control the aspiration unit 318 in the power supply 306.
The microprocessor operates according the flowchart of Figure 4, and accordingly controls the aspiration 318 and power supply 306 based on this flowchaxt. Step 400 detects voltage and current ~:
from monitor 308, and ~akes a ratio between this voltage and current at ~ep 402. This ratio is stored in a variable T. This variable measures a linkage of the instantaneous aspiration with varying phaco needle load and can be implemented in at least two different ~orms. ..
First we must recognize that a positive correlation has been established between the electrical power consumed by an ultrasonic transducer and the mechanLcal motion of a needle .
W092~ 14 ~ 09 9 7 8n P~T/US92/~0013 attacked to it. One way, therefore, would be tracking impedance (voltaye in/current in).
impedance - voltage x ~
current Z = V x 1 A multiplier circuit could be used to accomplish this. Changes in the load would allow the control system to compensate in a variety of ways by affecting both electrical power and aspiration levels. Alternately, the di~ference between commanded power levels and actual power consumed could also be measured directlY with only ~.
one multiplier circuit i.e.
power - voltage x current p e V X I
Both power levels (V*I) and V/I are ~:
referred:to generically herein as "Impedance". .. ;
Step ~04 makes a test by taking the ~ .
current variable T and subtr~cting a previous value of the variable T called herein TD ~ and then ::~
deter ining if T - Tp is greater than a value N. If :~
it is, this means that the impedance o~ the tissue currently is greater than the impedance at a previous time and that the current tissue is .:
therefore harder than the previous tissue.
Therefore, if the test at step 404 i5 positive, step 406 is executed which increases the a~piration rate!:
by N, and increases the power by N,. The flow then passes to step 408 in which the current value of T ~.
is ~tored in the location Tp in preparation for a ::
following cycle.
: I~ the result at step 404 is negative and : ~ the di~ference between T and TD is not greater than ."' .:
, .:
.. ...
7 8 ~
N, a second test is made at step 410. step 410 determines if the value of TD is greater than the curxent T by the amount N. If not, flow again passes to step 408. Therefore, if the difference between T and TD is less than the value N, no modification of aspiration or power takes place.
If TD is ~reater than T by more than the amount N, this indicates that the imp~dance at the previous time is greater than the impedance at the current time. Accordingly, the aspiration is decreased by the value N, and the power i5 decreased by the value N2 at step 412.
The following steps, 420 and 422, follow the lead of the aspiration controller 314 and power 15 supply controller 316 respec~ively. If these values are increased, the power to the appropriate component i also increased, according to a previously designated algorithm.
The specific structure and method steps enabling control o~ both power and aspiration according to the impedance encountered by the ,transducer is in no way taught or suggested by the 'prior art and is totally novel thereover. ' , A second embodiment of the invention is 25 shown,in Figure 5 where like numerals represent like el~ments. This second embodiment of the invention uses, in addition to the above monitoring system, a speech ~enerating module 500 which enables talking to the surgeon while he is operating.
Current phaco units have visual displays and audio feedback. The visual displays may show the mode in which the machine i5 engaged, ~or instance, foot pedal position and irrigation only, ~ ,' ':
: ~ , ~ , . , :' ' :, : ' ', ~, . ' ' ' ' . ' ~ ~ ~ 9 18 0 12 irrigation and aspiration, etc. The audio feedback may be different sounds in differen~ units that indicate a transition, such as a beep or click.
However, all of these sounds may be very con~using to a surgeon who is first learning to do the phaco procedure. Such a surgeon has many other things to concentrate on and often ti~es ~inds extra confusion in where on the foot pedal ~.hey are and precisely what is happening. The second embodiment of the present invention enables the use of commercially available speech generating equipment to help avoid this confusion.
According to this embodiment of this invention, the speech generating u~it 500 can be a ;
commercially available speech generating ch~p and audio e~uipment, or it can be, for instance, a series o~ tapes or recorded tracks which can be accessed by an appropriate processor~ SUch devices are well known in the art and will not be discussed further. This device operates according to the flowchart of Figure 6. Figure 6 has many common elements with Figure 4, and starts out in step 600 with d~tecting V and I and the value T. Step 602 :
determines if T is greater than TD by the value N, and if so, increases aspiration and power and also energizes speech qenerator 500 to say "tissue hardness increasing". ~S~ep 606 deter~ines if Tp is greater ~han T by a certain amou~t, and i~ yes, ::
executes steps 608 by decreasing aspiration and :
~0 enunciating that th~ tissue hard~ess is decreasing.
St~p 610 determines if thsre has been a change in aspiration or power ~upply control and if so, :i enunciates this chang~. For instance, a foot pedal .:
:'-' ' ' : . : .
' , .
~ " ' ',: : ' ., ' . :, ' ~
WO92~11814 PCT/US92/00013 2~99~8~
in position one might be enunciated to say 'lirrigation" and in position 2 would be enunciated as t'irrigation and aspiration". The enunciator might also say ~Iphaco fixed at 10%" or "phaco increased to 15%", and as the ~oot pedal or similar device was altered, then the enunciator could express, in increments, the new values. ,~
:':
This would enable the surgeon to maintain his concentration during thls very difficult time of the operation.
A third embodiment for the smart phacoemulsification system is described with reference to Figure 7 and the flowchart in Figure 8.
The key to the success~ul operation of this system is twofold. First, the surgeon has independent control over both transducer load power and aspiration reference levels. Secondly, the automatic control system power monitor and both power and aspiration compensation mechanisms provide measured improvements in the surgeon's control of ;
the transducer by linking the aspiration system compensation with the drive signal for the power compensation.
Electrical power supply 716 provides -voltage and current at soma fr~quency to transducer 700. Needle 702 makes contact with the human lens 704 and experiences a varying mechanical load dependent on the density of tissue layers. The su~yeon establishes reference power and aspiration levels via power level cu~.~,ol 700 and 708 aspiration level control 708. Electrical power supply 716 responds to power level commands and to .
' WO92/11814 PCT/U~92/00013 2 0 ~ 9 ~ 8 0 power compensation commands (voltage, c:urrent or possibly frequency adjustments). These commands originate from modules 720 and 718 respectively.
The varying mechanical load on needle 702 i5 reflected via transducer 700 as a chang~ing electrical load con~uming different amounts of electrical power from the reference power level command. This parameter detection is referred to herein as mechanical impedance.
lo Power monitor 112 senses load voltage and current from transducer 700 and computes electrical power. Transducer power consumption is fed to power comparison module 714 which outputs a difference between actual transducer power and the independent referenee level from the power command. Power compensation module 718 responds by appropriate electrical adjustments to power supply 716 such that transducer power consumption will track the independent c_. ~n~ ~rom the surgeon.
The unique ~afety improvement feature of this system results from the application of the power compensation drive signal (power comparison output) to the aspiration compensation module 710.
The output o~ the aspiration compensation module 710 will be an adjustment to vacuum, or flow or both, depending on the type of aspiration system.
As with power the surgeon has independent input control via aspiration control 708 to press the output ~vacuum and flow~ of aspiration system 706. The entire system follows a straightforward control scheme as described by the flowchart of Figure 8. note that any changes induced by the . ~..
21~7~0 compensation modules will force the load power to track the independent power level command from the surgeon. Also, the aspiration changes will be added to the independent aspiration l~vel commands ~rom the surgeon. In this way, the surgeon main~ains control over the procedure.
The Figure 8 flowchart shows detecting the ~:
transducer load and ~lectrical powar at step 800, followed by determinations at step 802 and 808 2S to whether the power is less than or greater than a reference Pr. I~ the current electrical power P, is less than P" higher density tissue layers are recognized at step 804, followed by the aspiratian increase load power at step 806. If the load P, is recognized as greater than P, at step 808, lower density tissue layers are recognized at step 810, followed by a decrease in the aspiration and step 812. Step 814 determines if no change in relative -~
tissue density is recognized, followed by no change in load power or aspiration at step 816.
Experiments have been carried out to verify that both mechanical impedance and resonant frequency change is a function of the hardness of material that i5 encountered by phaco needle 302 during such operations. Figure 9 shows an actual experimentally obtained mechanical impedance versus frequency spectra oE loaded and unloaded phaco needles. This was measured with a Hewlett Packard impedance analyzer using ~2 volts ~xci~ation, and a hard almond; used in simulating a hardened lens portion of an eye. Figure 9 shows the change in phase and impedance shifting with loading. Two resonant peaks were observed at approximately 28.87S
WO92~11814 PCT/US92/00013 2~978~
KHZ and 59.5 KHZ. It is believed by tlle applicant that these two peaks correspond ~o the fundamental electromechanical re~onance of ~he piezoelectric driving crystal. These two peaks may also be due to the longitudinal and transverse piezoelectric coe~ficients of the crystal.
The second impedance spectrum shown in Figure lO shows tha change in hardness effects as simulated by a chocolate covered peanut: M&M (TM) candy. The frequency of shifts of the two resonant peaks are approximately one l KHZ and 375 hertz for the low and high frequency resonant peaks respectively. This demonstrates the practicability of the system by its ability to determine a peanut within a chocolate covered M&M peanut candy. ' In operation, a map will be formed between the phase angle (r~son~nt frequency), mechanical impedance, and hardness of the material. This map can be ~rom a plot such as shown in Figs 9 and lO, made while observing the characteristics of the material on which the operation is occurring.
While these changes in impedance can be determined and the observation of the frequency ~ ' shi~t can also be determined as the phaco needle -encounters loads of different hardness, it has been found that it may be difficult to identify these changes under high level excitation ~llO volt) conditions due to the high electrical noise. The , -~ nce and frequency shift are more easily observable under low level excitation conditions of such as i2 volts, but detection of this on a practical scale requires more sp~eciali~ed techni~ues than those of tbe previous embodiments.
.~''':' wos2tl1814 PCT/US92/00013 20~7~
In order to effect this low level process, the fourth embodiment of th~ present invention detects the change in hardness of the material by the addition of solid state microsensors which provide the means of load hardness de~ec~ion without electrical interference from the large voltaqes driving the piezoelectric or magne~ostrictive crystal. Figure ll shows a general block diagram of a structure using the process, it being understood that the concepts of all the previous embodiments could be added to ~he basic modification of Figure 11 .
Figure ll shows the improved structure for load sensing defined according to the fourth embodiment. This fourth embodiment includes two ~orce transducer~ lO00 and 1002. The force transducer lO00 is a driving force transducer which is driven by power supply 306 under control of microprocessor 312. The voltage excitation to the first force transducer lO00 causes expansion and contraction of phaco needle 302. An aspira~or 30~
and fluid supply lO03 is also provided. It should be understood that Figure ll may also include the auxiliaxy structure shown in any of Figures 3-8, although this is not shown in detail ~or easier underst~n~jn~.
The dri~en elem~nt 1002 includes a separate piezoelectric crystal 1006 which is stressed at the resonant frequency of the combined electrical and mechanical circuit and for this ~-purpose is mechanically coupled to phaco needle 302.
~his mechanical coupling provides the second ' , .
7 8 ~
~8 piezoelectric crystal mechanically in parallel with a first piezoelectric crystal 1008 of the first force transducer lOO0 to sense the moY~emen-t of the needle 302 in this way. Needle 302 is moved by a large surge of voltage which can cau~e noi~e in the resultant measurement. However, the auxiliary crystal lOO6 is moved by the movement of the needla, rather than by the driving voltage. The ~ompression and release gives off a vol~age that is proportional to this amount of compression of the piezoelectric crystal in correspondenc~ with known characteristics of the crystal. The microprocessor 312 therefore obtains a voltage related to the amount of contraction of the crystal, as well as a voltage indicative of the amount of power pro~ided to the crystal lOO0, this power ~eing coupled to the needle 302 to dri~e it. ~his driv~n element 1002 has been called a "pony" element by the inventor, since it "rides" on the phaco needle.
~he secondary sensing element 1002 is '~
placed in a location to convert the mechanical stress thereon into electrical voltage or current.
These elements can be placed at nodal points where the stress/velocity is ~ r or anti-notal points where the stress/velocity i5 minimum. The signals generated by the sen~ors will comply with the characteristic equations for th~ transducer when ~wo senslng elements are used in a di~ferential con~iguration to cancel e~LO~ 5.
In one approach, the impedance would be continually monitored as the transducer and in another approach the ~ransducer would pulse with the first period o~ the pulse being used as a sensing , 1 . ',:
, .' ~..' WO92/11814 pcT/us92/oonl3 20~7~0 period of time with the following period being used as a operating period. During the sensing period the power of the transducer is lowered to a level below which cavitation will not occur and transducer losses are minimum.
The amount of aspiration is then defined as a function of flow rate and vacuum llevel and either or both of these can be controllled.
The operation of this structure takes place accordance with the flow chart of Figure 12.
The flow chart of Figure 12 shows the operation of the present invention, it being unders~ood that this operation might need to be modified somewhat.
However, th~se modifications could easily be done by those of skill in the art by repeating the simulation discussed above with respect to Figures 9 and lO. While Figures 9 and 10 used an almond and a M&M respectively, actual values for cut-off could use an actual human eye from a cadaver or an animal for better simulating the exact characteristics that will need to be controlled.
Figure 12 starts with step 1200 of getting a map. This map, however, must be determined and stored in advance, and would typically be done by making similar plots ~o those of Figures 9 and 10.
While the simulations of Figures 9 and 10 were done with various commercially available food materials which had varying hardness~, an actual map ~or thP
system would be better conducted using an actual human eye f~om a cadaver or the like. A similar simula~ion to tha~ shown in Figures 9 and 10 is conducted on such an~eye and a characteristic chart showing both the mechanical impedance~ of such a ~.. .
.
.
.
.:
~:
WO92/1~814 PCT/US92/00013 7 ~ 0 material as well as the resonant frequencies thereof should be stored as a one or two dimensional map.
This map is the map that is obtained in step 1200.
The actual flow chart begins with step 1202 where the amount of the needle movement is .
detected. In this emho~; ~nt this amount o~ needle detection is determined by monitoring t.he voltage from piezoelectric crystal 1006, ~his voltage being proportional to the amount of movement of the needle. The amount of power being fed to the needle is determined at.step 1202. Step 1204 receives a ... : .
voltage ~rom the crystal 1002, and determines the .' amount of needle movement as a difference between a .' current voltage representing a current needle position and a previous voltage representin~ a ~:
previous needle position. At step 1206 the mechanical impedance presented to the needle is : .
detected according to a proportionality between .
power detected in step 1202 and a amount of a needle movement detected at s~ep 1204. The mechanical impedance may also be wei~hted by a weighing factor .
which may be a linear factor or may be itself . .. ..
dependent on power or movement amount. For instance, at higher powers the mechanical impedance may a different ratio, since the material can only react by some -Yi amount no matter how high tha power. This ~Q~h~ical impedance is then stored as a current value. At step 1208 a current resonant ~: :
frequency is calcul~ted based on the current amount of needle mov~ ~nt d~termined at step 1204. This : m2y be done in many different ways, simplest among which migh~ be to store a plurality of recznt determined values and to conduct a fast Fourier . .
. ..
, 2 ~ 7 ~ ~
transform on these values to determine current frequency components. The current mechanisal impedance and current resonant frequancy are then used to address the map to detect the part of the eye being operated on. In this preferred embodiment step 1210, which detects this part of the eye, ouLpuLs a number which is indicative of the part of the eye currently being operated on. For instance, number l might mean nucleus, 2 means lens and so on.
Step 1212 then adjusts the power output, and aspiration and fluid control to follow the part of the eye operated on. The way in which the amount of power would be determined is similar to the way in which the map is determined -- when using an actual model the values which cause punch-through and which are acceptable can be easily determined.
Accordingly, this actual model can be used to determine what parameters output correspond to what degree of operation.
Of course it should be understood in the above flow chart that many modifications are possible. For example, while the flow chart explains thak both mechanical impedance or resonant frequency be used, it should be understood that either one by itself may be enough to find the current location in the eye and hence a two dimensional map o~ either resonant fxequency or mechanical impedance could be used. While the techniques of the present invention are specifically related to operation within a human eye, it should be ~ ized that these techni~ues could be used for operation in many o~her orqans or in anything else.
-,, - ' ' . : .
; , ; , . ! . ;
~0'~7~ :
Figure 13 shows a fifth embodiment of the .
present invention which is an alternative to the fourth embodiment. This fi~th embodiment uses at least one solid state accelerometer to detect the resonant frequency characteristic of the encountered needle load. F.igure 13 is simplified by removing all auxiliary structure used for the n~eedle, and only shows the driving crystal 1008 and its mechanically linked accelerometer 1020. In this way, the microprocessor 312 receives information indicative of the amount of power driven to the crystal 1008 as well as the information from the accelerometer. An accelerometer is commonly available from many different sources. The fifth embodiment of Figure 13 would operate similarly to that explained with reference to the ~low chart of Figure 12. In summary the accelerometer would be used to determine how rapidly the needle accelerates and decelerates and when a hard~r material is hit ..
the structure would accelerat~ or decelerate slower ;j;
under a heaviex load, thereby providing an automated detection of material hardness. The force meter, in ~.' contrast, determines how much force the needle is encountering by how much it is moving. By the detection of how much force is on the needle, one can determine me~hAnical impedance.
Although only a few embodiments have been described in detail above, those having ordinary skill in the art will understand that many ::;
~:THOD AND APPARAT~JS
FI~ n OF TEIE lNv~ oN:
The present invention relates to a computer controlled "smart" phacoemulsification apparatus, and more specifically ~o one which controls power delivery ~o the needle of the transducer and also controls an amount of aspiration based on a load on the tip of the transducer.
BACRGROUND AND SUMM~RY OF THE lNv~NllON~
Eye surgery is a complicated and delicate process. One common eye surgery is cataract extraction. There are currently several methods of acceptable cataract extraction, including phacoemulsification. Phacoemulsification is not in itself new, but as currently done has many problems.
Phacoemulsification involves the ;
generation of an ultrasonic signal which is a series ;
of cyclical mechanical vibrations in a frequency range beyond that detectable by normal human hearing. The ultrasonic signal is generated by a transducer that is driven by an electrical signal in a fre~uency range between 20 and 100 kilohertz in equipment pr~sently available for this application.
Typically the transducer mechanism includes either piezoelectric or magnetostrictive elements.
The energy resulting from the ultrasonic signal is coupled ~o the human lens by a needle attached to the transducer. Typically the needle is made from an inert alloy o~ titanium or stainless ste~l. Once coupled to the human lens, the ultrasonic energy fragments and emulsified the cataract. Once this nuclear material is fragmented, - . -.,.;.
' ',' .
.. , ,,, ,. ,,,. ", , ., . . . . ~ , . , ... ... ~, .. .
WO9~/11814 PCT/US92/00013 h~ O ~ 9 7 80' however, it must be removed from th~ eye. In order to do this, the ultrasonic needle is hollow, and an aspiration system is oonnected to the hollow area in order to remove the fragmented particles. A
balanced salt solution is also injected in order to maintain the stability or pressure, a.nd this infusion occurs around the vibrating titanium needle through a sleeve.
An example of such a phacoemulsification unit is shown in U.S. Patent 4,223,676. Current phacoemulsification surgery allows the surgeon to choose either a ~ixed ph~co mode in which the power setting to the transducer is fixed, or a linear mocle :
in which the phaco power can be changed by the power pedal. In the fixed mode, the phaco unit is either on or off depending on whether the pedal is depressed or not. The value of power setting is preset. In the linear mode, the further depression of the pedal varies the amount of power to the transducer and thereby the ultrasonic energy. The aspiration during this operation is preset. A third mode of phacoemulsifica~ion which has been recently introduced keep~ the phaco power fixed and varies the aspiration depending on the foot pedal.
The inventor of the present invention has recognized a problem which exists in these prior operations. In order to fully understand this, one must consider the structure of the lens of the human eye. Figure 1 shows diagrammatically a human lens which has an outer, fine, transparent tissue or capsule shown as layer lO0. ~nterior to this is a : . sof~ material known as the cortex 102, which surrounds the transition layers 104. The nucleus of ......
WO92/11814 PCT/~S92/00013 2~7~a the lens is a hard, compressed lens mal:erial shown as 106. The inventor o~ ~he present invention has first noted that in these soft outer cortical layers, little aspiration is required, but more aspiration is required in ~he harder transitional layers and even more in the hardest nucleus layer.
However, pos~erior ~o the hardest nucleaus layer is a less hard transitional layer followed by A soft cortex. A majority of the complications during eye surgery are caused not by the amount of phacoemulsification, but by overaspiration in conjunction with the emulsification causing a "punch through" through the posterior lens capsule. This is particularly dangerous since the center of the lens needs more energy (aspiriation and emulsification) than the outer soft cortical layer, i "
and therefore therç is more possibility of punch-through at this higher energy level and high aspiration level.
Eye surgery involv~s ~orming an opening in the front of the capsule, and locating the phaco needle first into the so~t cortex. ~t this time the needle will experi~nce a minimal load in th~ soft cortex. As the needle goes further into the nucleus which is progressively harcler, the mechanical load i increases. A~ter passing through the nucleus, the process reverses, and the mechanical load will quickly decrease. It is at: ~his point that the inventor of the present invention has Pound that the control of aspiration becomes critical. O~er-aspiration at this time can cause the posterior capsule to be ruptured. However, determination o~ -the relative hardness of these layers has previ~usly WO92/llgl4 PCT/US92/00013 ~0~7~-~
been left to the observation skills and manual skills of the surgeon. However, the surgeon has many other things on his mind and also simply may not be able to react fast enough in order to properly change the aspiration amount.
The inventor of the present invention has recognized that a hard nucleus consumes more energy than a soft nucleus, thereby changing the impedance, ~:
and more specifically the mechanical impedance, introduced to the ultrasonic tip. According to the present invention, this difference is fed back to a :
microprocessor in order to modify the aspiration system dependent on the hardness of the material being operated upon. This reduces the problem of "punch through" because it allows automatic checking of the hardness of the material and automatic adjustment of the aspiration delivery in a way which is ~aster than could ever be done using human .
reflexes. Such a syst~m has never been described in the prior art. : .
One way in which this is done i5 by detecting mechanical impedance of the tissue, using, for example, a sensor to de~tect response to a stimulus.
One general feature of the present -~
invention is the recoynition by the inventor of the : .
present invention that soft tissue requixes a low .
stroke or low velocity and tha~ hard tissue requires a high stroke and high velocity. The mechanical impedance of any material including the human eye is a function of the density p and sound velocity C. It ~ usually has a resistive component ~ and a reactive component X,. Compliant or deformable tissue presents primarily a resistive impedance to the : ,.
WO92/11814 PCT/US~2/00013 2~9~78~
driving force. Non-compliant or non-deformable tissues are primarily a reactive impedance. In other words, soft tissue will be more resistive and hard tissue will be more reactive.
One approach to detecting mechanical impedance from a piezoelectric hand piece is to read the driving voltage and current. Here not only magnitude but also phase will be monitored where zero phase difference will indicate a resistive load on soft tissue. A large phase difference would indicate a reactive load or hard tissue. Another approach would include determining the resonant frequency of the loaded hand piece in relation to a reference, which can be the resonant frequency of the unloaded hand piece. If the transducer is ~;
formed as a half wavelength straight bar, its resonant frequency will not change for purely resistive loads and can be determined according to the equation .: .. .
tan (2~f x) = 0 :
where f is the operational fre~uency, c is the speed of sound in the bar, and x is the length of the barO
For a purely reactive load, the resonan~ frequency is determined by the equation tan (2~f x ) =
c Zo ..
where XL is the reac~ive load and Z0 is the characteristic impedance o~ the bar. If the .
' :
.. :.. , ., . : ~ ,: . . , - - - -. .. ~; , ,, ~ 1,'. . . .,.. - . - '; . ,; . ~
rl ~ ~
transducer is made as a step horn type to provide amplification of the displacement, the~ resonant frequency will change for either resiC;tive or reactive loads. A typical step horn device is shown in Figure 14 with its two parts 1050 and 1052. The lengths X of the parts 1050 and 1052 are equal to one another but their areas differ by a factor of N>10.
For a device Qf this type, the resonant frequency is determined according to the equation tan (2~f x) = R
c 20 where X is the length shown in Figure 14 and Z0 is the characteristic impedance of the transducer material as shown in Figure 15. ~rhe part 1052 has the impP~nce zo while the part 1050 has the characteristic imre~nce N x Z0. For purely reactive loads the resonant frequency can be determined from the equation , (tan 2~f x) = (XL)' c Z.
These equations are general and exemplary and different needle/transducer arrangements could use different equations.
Many attempts have been made in the prior art in order to atkempt to automate operation processes. U.S. Patent 4,223,676 is one such attempt and defines one type of ultrasonic aspirator of the type previously described above. Column 8 of this patent recognizes that frequency fluctuates ..
during the course of an operation, and in order to :
attempt to maintain the amount of power delivery as . ',:
; ' ~'. .
, , , ~ - ~ , , , . - , , . .. . . ~ .
2Q~s~sa constant, this patent tezches monitoring actual and expected parameters of the system. The difference between these two parameters is fed back in a .
feedback loop to control the stroke level of the s vibrator. Therefore, while the power of the system :-is controlled, there is no teaching of controlling the amount of aspiration, and as such the problem of "punch through" would still remain in this system. ..
Similarly, U.S. Patent 3, 9~4, 487 teaches a structure which monitors the impedance of the electric cutting apparatus, and feeds back this :~
impedance to determine the amount of power to be provided. This device does not teach controlling the amount of aspiration, and there~ore would not alleviate the problem of "punch through". . ;
Simllarly, U.S. Patent 4, 126, 137 teaches sensing of the impedance of the tissues to set the amount of drive to an electro-surgical unit.
U.S. Patent 4,024,866 relates to a device which teaches controlling the amount of suction in a suction conduit for eye surgery. Column 7, lines 24 ++ teach that an upper limit is placed on the amount of suction to prevent an excessive amount of suction. While this might provide an upper limit, it does not heIp the user to obtain better control and better feedback within the system BRIEF DESCRIPTION OF THE DRAWIN~S~
These and other aspects of the invention ~:
: will now be described i~ detail with reference to the accompanying drawings, in which: .
Figure l shows a schematic view of the human eye;
' ' .
.~
' ' ' :
WO92/11814 PC~/US92/00013 2a~978~
Figure 2 shows a representati~e amount of aspiration required in a travPrsal through the eye;
Figure 3 shows a blocked diagram representation of a first embodiment of the present i~vention;
Figure 4 show~ a flow chart of operation . : .
of this first embodiment;
Figure 5 shows a blocked diagram representation of a second embodiment of the present invention which uses a speech enunciator to aid the surgeon with his operation;
Figure 6 shows a flow chart of operation . of the second embodiment.
Figure 7 shows a structure of the third embodiment of the present invention; and Figure 8 shows a flow chart of this operation. . -Figures 9 and 10 show characteristic ~ ;.
curves for characteristics i~ Almond, and a peanut "M & M(TM)", respectively;
Figure 11 shows~a block di~gram of a fourth embodiment of the invention; ~' Figure 12 shows a flowchart of operation :. :
of this fourth embodime~t; and Pigure 13 shows a block diagram of a fifth embodiment of the invention; and . :
Figure 14 shows a typical phaco needle. ~
:
1~ 01~ 0~ q~HE ~ ;rr;n~13D ~D1...L~. . 5:
A presently preferred embodiment will now be described ln detail wi~h respect ~o ~he accompanying drawings. Figure 3 shows a first ,~ '..
. ~ .
7 ~ ~
embodiment of the invention. Transducer 300 is shown attached to phaco needle 302 which is adapted to come into contact with a lens 304 o~ the human eye. The power supplied by power supply 306 to the transducer 300, and at the same ~ime the voltage and ;.
current is monitored by monitor 30~. Monitor 308 monitors the voltage and current, and produces :
analog si~nals which are converted by analog to digital converter into digital si~nals, and are input to microprocessor 312. Microprocessor 312 can be any commercially available type. An aspiration control 314 is also input to microprocessor as is a power supply control 316. These devices can be either dial-type potentiometers or the usual surgeon's foot pedal, and produce a command signal indicative of the amount o~ aspiration and power respectively desired. Microprocessor 312 produces analog signals which control the aspiration unit 318 in the power supply 306.
The microprocessor operates according the flowchart of Figure 4, and accordingly controls the aspiration 318 and power supply 306 based on this flowchaxt. Step 400 detects voltage and current ~:
from monitor 308, and ~akes a ratio between this voltage and current at ~ep 402. This ratio is stored in a variable T. This variable measures a linkage of the instantaneous aspiration with varying phaco needle load and can be implemented in at least two different ~orms. ..
First we must recognize that a positive correlation has been established between the electrical power consumed by an ultrasonic transducer and the mechanLcal motion of a needle .
W092~ 14 ~ 09 9 7 8n P~T/US92/~0013 attacked to it. One way, therefore, would be tracking impedance (voltaye in/current in).
impedance - voltage x ~
current Z = V x 1 A multiplier circuit could be used to accomplish this. Changes in the load would allow the control system to compensate in a variety of ways by affecting both electrical power and aspiration levels. Alternately, the di~ference between commanded power levels and actual power consumed could also be measured directlY with only ~.
one multiplier circuit i.e.
power - voltage x current p e V X I
Both power levels (V*I) and V/I are ~:
referred:to generically herein as "Impedance". .. ;
Step ~04 makes a test by taking the ~ .
current variable T and subtr~cting a previous value of the variable T called herein TD ~ and then ::~
deter ining if T - Tp is greater than a value N. If :~
it is, this means that the impedance o~ the tissue currently is greater than the impedance at a previous time and that the current tissue is .:
therefore harder than the previous tissue.
Therefore, if the test at step 404 i5 positive, step 406 is executed which increases the a~piration rate!:
by N, and increases the power by N,. The flow then passes to step 408 in which the current value of T ~.
is ~tored in the location Tp in preparation for a ::
following cycle.
: I~ the result at step 404 is negative and : ~ the di~ference between T and TD is not greater than ."' .:
, .:
.. ...
7 8 ~
N, a second test is made at step 410. step 410 determines if the value of TD is greater than the curxent T by the amount N. If not, flow again passes to step 408. Therefore, if the difference between T and TD is less than the value N, no modification of aspiration or power takes place.
If TD is ~reater than T by more than the amount N, this indicates that the imp~dance at the previous time is greater than the impedance at the current time. Accordingly, the aspiration is decreased by the value N, and the power i5 decreased by the value N2 at step 412.
The following steps, 420 and 422, follow the lead of the aspiration controller 314 and power 15 supply controller 316 respec~ively. If these values are increased, the power to the appropriate component i also increased, according to a previously designated algorithm.
The specific structure and method steps enabling control o~ both power and aspiration according to the impedance encountered by the ,transducer is in no way taught or suggested by the 'prior art and is totally novel thereover. ' , A second embodiment of the invention is 25 shown,in Figure 5 where like numerals represent like el~ments. This second embodiment of the invention uses, in addition to the above monitoring system, a speech ~enerating module 500 which enables talking to the surgeon while he is operating.
Current phaco units have visual displays and audio feedback. The visual displays may show the mode in which the machine i5 engaged, ~or instance, foot pedal position and irrigation only, ~ ,' ':
: ~ , ~ , . , :' ' :, : ' ', ~, . ' ' ' ' . ' ~ ~ ~ 9 18 0 12 irrigation and aspiration, etc. The audio feedback may be different sounds in differen~ units that indicate a transition, such as a beep or click.
However, all of these sounds may be very con~using to a surgeon who is first learning to do the phaco procedure. Such a surgeon has many other things to concentrate on and often ti~es ~inds extra confusion in where on the foot pedal ~.hey are and precisely what is happening. The second embodiment of the present invention enables the use of commercially available speech generating equipment to help avoid this confusion.
According to this embodiment of this invention, the speech generating u~it 500 can be a ;
commercially available speech generating ch~p and audio e~uipment, or it can be, for instance, a series o~ tapes or recorded tracks which can be accessed by an appropriate processor~ SUch devices are well known in the art and will not be discussed further. This device operates according to the flowchart of Figure 6. Figure 6 has many common elements with Figure 4, and starts out in step 600 with d~tecting V and I and the value T. Step 602 :
determines if T is greater than TD by the value N, and if so, increases aspiration and power and also energizes speech qenerator 500 to say "tissue hardness increasing". ~S~ep 606 deter~ines if Tp is greater ~han T by a certain amou~t, and i~ yes, ::
executes steps 608 by decreasing aspiration and :
~0 enunciating that th~ tissue hard~ess is decreasing.
St~p 610 determines if thsre has been a change in aspiration or power ~upply control and if so, :i enunciates this chang~. For instance, a foot pedal .:
:'-' ' ' : . : .
' , .
~ " ' ',: : ' ., ' . :, ' ~
WO92~11814 PCT/US92/00013 2~99~8~
in position one might be enunciated to say 'lirrigation" and in position 2 would be enunciated as t'irrigation and aspiration". The enunciator might also say ~Iphaco fixed at 10%" or "phaco increased to 15%", and as the ~oot pedal or similar device was altered, then the enunciator could express, in increments, the new values. ,~
:':
This would enable the surgeon to maintain his concentration during thls very difficult time of the operation.
A third embodiment for the smart phacoemulsification system is described with reference to Figure 7 and the flowchart in Figure 8.
The key to the success~ul operation of this system is twofold. First, the surgeon has independent control over both transducer load power and aspiration reference levels. Secondly, the automatic control system power monitor and both power and aspiration compensation mechanisms provide measured improvements in the surgeon's control of ;
the transducer by linking the aspiration system compensation with the drive signal for the power compensation.
Electrical power supply 716 provides -voltage and current at soma fr~quency to transducer 700. Needle 702 makes contact with the human lens 704 and experiences a varying mechanical load dependent on the density of tissue layers. The su~yeon establishes reference power and aspiration levels via power level cu~.~,ol 700 and 708 aspiration level control 708. Electrical power supply 716 responds to power level commands and to .
' WO92/11814 PCT/U~92/00013 2 0 ~ 9 ~ 8 0 power compensation commands (voltage, c:urrent or possibly frequency adjustments). These commands originate from modules 720 and 718 respectively.
The varying mechanical load on needle 702 i5 reflected via transducer 700 as a chang~ing electrical load con~uming different amounts of electrical power from the reference power level command. This parameter detection is referred to herein as mechanical impedance.
lo Power monitor 112 senses load voltage and current from transducer 700 and computes electrical power. Transducer power consumption is fed to power comparison module 714 which outputs a difference between actual transducer power and the independent referenee level from the power command. Power compensation module 718 responds by appropriate electrical adjustments to power supply 716 such that transducer power consumption will track the independent c_. ~n~ ~rom the surgeon.
The unique ~afety improvement feature of this system results from the application of the power compensation drive signal (power comparison output) to the aspiration compensation module 710.
The output o~ the aspiration compensation module 710 will be an adjustment to vacuum, or flow or both, depending on the type of aspiration system.
As with power the surgeon has independent input control via aspiration control 708 to press the output ~vacuum and flow~ of aspiration system 706. The entire system follows a straightforward control scheme as described by the flowchart of Figure 8. note that any changes induced by the . ~..
21~7~0 compensation modules will force the load power to track the independent power level command from the surgeon. Also, the aspiration changes will be added to the independent aspiration l~vel commands ~rom the surgeon. In this way, the surgeon main~ains control over the procedure.
The Figure 8 flowchart shows detecting the ~:
transducer load and ~lectrical powar at step 800, followed by determinations at step 802 and 808 2S to whether the power is less than or greater than a reference Pr. I~ the current electrical power P, is less than P" higher density tissue layers are recognized at step 804, followed by the aspiratian increase load power at step 806. If the load P, is recognized as greater than P, at step 808, lower density tissue layers are recognized at step 810, followed by a decrease in the aspiration and step 812. Step 814 determines if no change in relative -~
tissue density is recognized, followed by no change in load power or aspiration at step 816.
Experiments have been carried out to verify that both mechanical impedance and resonant frequency change is a function of the hardness of material that i5 encountered by phaco needle 302 during such operations. Figure 9 shows an actual experimentally obtained mechanical impedance versus frequency spectra oE loaded and unloaded phaco needles. This was measured with a Hewlett Packard impedance analyzer using ~2 volts ~xci~ation, and a hard almond; used in simulating a hardened lens portion of an eye. Figure 9 shows the change in phase and impedance shifting with loading. Two resonant peaks were observed at approximately 28.87S
WO92~11814 PCT/US92/00013 2~978~
KHZ and 59.5 KHZ. It is believed by tlle applicant that these two peaks correspond ~o the fundamental electromechanical re~onance of ~he piezoelectric driving crystal. These two peaks may also be due to the longitudinal and transverse piezoelectric coe~ficients of the crystal.
The second impedance spectrum shown in Figure lO shows tha change in hardness effects as simulated by a chocolate covered peanut: M&M (TM) candy. The frequency of shifts of the two resonant peaks are approximately one l KHZ and 375 hertz for the low and high frequency resonant peaks respectively. This demonstrates the practicability of the system by its ability to determine a peanut within a chocolate covered M&M peanut candy. ' In operation, a map will be formed between the phase angle (r~son~nt frequency), mechanical impedance, and hardness of the material. This map can be ~rom a plot such as shown in Figs 9 and lO, made while observing the characteristics of the material on which the operation is occurring.
While these changes in impedance can be determined and the observation of the frequency ~ ' shi~t can also be determined as the phaco needle -encounters loads of different hardness, it has been found that it may be difficult to identify these changes under high level excitation ~llO volt) conditions due to the high electrical noise. The , -~ nce and frequency shift are more easily observable under low level excitation conditions of such as i2 volts, but detection of this on a practical scale requires more sp~eciali~ed techni~ues than those of tbe previous embodiments.
.~''':' wos2tl1814 PCT/US92/00013 20~7~
In order to effect this low level process, the fourth embodiment of th~ present invention detects the change in hardness of the material by the addition of solid state microsensors which provide the means of load hardness de~ec~ion without electrical interference from the large voltaqes driving the piezoelectric or magne~ostrictive crystal. Figure ll shows a general block diagram of a structure using the process, it being understood that the concepts of all the previous embodiments could be added to ~he basic modification of Figure 11 .
Figure ll shows the improved structure for load sensing defined according to the fourth embodiment. This fourth embodiment includes two ~orce transducer~ lO00 and 1002. The force transducer lO00 is a driving force transducer which is driven by power supply 306 under control of microprocessor 312. The voltage excitation to the first force transducer lO00 causes expansion and contraction of phaco needle 302. An aspira~or 30~
and fluid supply lO03 is also provided. It should be understood that Figure ll may also include the auxiliaxy structure shown in any of Figures 3-8, although this is not shown in detail ~or easier underst~n~jn~.
The dri~en elem~nt 1002 includes a separate piezoelectric crystal 1006 which is stressed at the resonant frequency of the combined electrical and mechanical circuit and for this ~-purpose is mechanically coupled to phaco needle 302.
~his mechanical coupling provides the second ' , .
7 8 ~
~8 piezoelectric crystal mechanically in parallel with a first piezoelectric crystal 1008 of the first force transducer lOO0 to sense the moY~emen-t of the needle 302 in this way. Needle 302 is moved by a large surge of voltage which can cau~e noi~e in the resultant measurement. However, the auxiliary crystal lOO6 is moved by the movement of the needla, rather than by the driving voltage. The ~ompression and release gives off a vol~age that is proportional to this amount of compression of the piezoelectric crystal in correspondenc~ with known characteristics of the crystal. The microprocessor 312 therefore obtains a voltage related to the amount of contraction of the crystal, as well as a voltage indicative of the amount of power pro~ided to the crystal lOO0, this power ~eing coupled to the needle 302 to dri~e it. ~his driv~n element 1002 has been called a "pony" element by the inventor, since it "rides" on the phaco needle.
~he secondary sensing element 1002 is '~
placed in a location to convert the mechanical stress thereon into electrical voltage or current.
These elements can be placed at nodal points where the stress/velocity is ~ r or anti-notal points where the stress/velocity i5 minimum. The signals generated by the sen~ors will comply with the characteristic equations for th~ transducer when ~wo senslng elements are used in a di~ferential con~iguration to cancel e~LO~ 5.
In one approach, the impedance would be continually monitored as the transducer and in another approach the ~ransducer would pulse with the first period o~ the pulse being used as a sensing , 1 . ',:
, .' ~..' WO92/11814 pcT/us92/oonl3 20~7~0 period of time with the following period being used as a operating period. During the sensing period the power of the transducer is lowered to a level below which cavitation will not occur and transducer losses are minimum.
The amount of aspiration is then defined as a function of flow rate and vacuum llevel and either or both of these can be controllled.
The operation of this structure takes place accordance with the flow chart of Figure 12.
The flow chart of Figure 12 shows the operation of the present invention, it being unders~ood that this operation might need to be modified somewhat.
However, th~se modifications could easily be done by those of skill in the art by repeating the simulation discussed above with respect to Figures 9 and lO. While Figures 9 and 10 used an almond and a M&M respectively, actual values for cut-off could use an actual human eye from a cadaver or an animal for better simulating the exact characteristics that will need to be controlled.
Figure 12 starts with step 1200 of getting a map. This map, however, must be determined and stored in advance, and would typically be done by making similar plots ~o those of Figures 9 and 10.
While the simulations of Figures 9 and 10 were done with various commercially available food materials which had varying hardness~, an actual map ~or thP
system would be better conducted using an actual human eye f~om a cadaver or the like. A similar simula~ion to tha~ shown in Figures 9 and 10 is conducted on such an~eye and a characteristic chart showing both the mechanical impedance~ of such a ~.. .
.
.
.
.:
~:
WO92/1~814 PCT/US92/00013 7 ~ 0 material as well as the resonant frequencies thereof should be stored as a one or two dimensional map.
This map is the map that is obtained in step 1200.
The actual flow chart begins with step 1202 where the amount of the needle movement is .
detected. In this emho~; ~nt this amount o~ needle detection is determined by monitoring t.he voltage from piezoelectric crystal 1006, ~his voltage being proportional to the amount of movement of the needle. The amount of power being fed to the needle is determined at.step 1202. Step 1204 receives a ... : .
voltage ~rom the crystal 1002, and determines the .' amount of needle movement as a difference between a .' current voltage representing a current needle position and a previous voltage representin~ a ~:
previous needle position. At step 1206 the mechanical impedance presented to the needle is : .
detected according to a proportionality between .
power detected in step 1202 and a amount of a needle movement detected at s~ep 1204. The mechanical impedance may also be wei~hted by a weighing factor .
which may be a linear factor or may be itself . .. ..
dependent on power or movement amount. For instance, at higher powers the mechanical impedance may a different ratio, since the material can only react by some -Yi amount no matter how high tha power. This ~Q~h~ical impedance is then stored as a current value. At step 1208 a current resonant ~: :
frequency is calcul~ted based on the current amount of needle mov~ ~nt d~termined at step 1204. This : m2y be done in many different ways, simplest among which migh~ be to store a plurality of recznt determined values and to conduct a fast Fourier . .
. ..
, 2 ~ 7 ~ ~
transform on these values to determine current frequency components. The current mechanisal impedance and current resonant frequancy are then used to address the map to detect the part of the eye being operated on. In this preferred embodiment step 1210, which detects this part of the eye, ouLpuLs a number which is indicative of the part of the eye currently being operated on. For instance, number l might mean nucleus, 2 means lens and so on.
Step 1212 then adjusts the power output, and aspiration and fluid control to follow the part of the eye operated on. The way in which the amount of power would be determined is similar to the way in which the map is determined -- when using an actual model the values which cause punch-through and which are acceptable can be easily determined.
Accordingly, this actual model can be used to determine what parameters output correspond to what degree of operation.
Of course it should be understood in the above flow chart that many modifications are possible. For example, while the flow chart explains thak both mechanical impedance or resonant frequency be used, it should be understood that either one by itself may be enough to find the current location in the eye and hence a two dimensional map o~ either resonant fxequency or mechanical impedance could be used. While the techniques of the present invention are specifically related to operation within a human eye, it should be ~ ized that these techni~ues could be used for operation in many o~her orqans or in anything else.
-,, - ' ' . : .
; , ; , . ! . ;
~0'~7~ :
Figure 13 shows a fifth embodiment of the .
present invention which is an alternative to the fourth embodiment. This fi~th embodiment uses at least one solid state accelerometer to detect the resonant frequency characteristic of the encountered needle load. F.igure 13 is simplified by removing all auxiliary structure used for the n~eedle, and only shows the driving crystal 1008 and its mechanically linked accelerometer 1020. In this way, the microprocessor 312 receives information indicative of the amount of power driven to the crystal 1008 as well as the information from the accelerometer. An accelerometer is commonly available from many different sources. The fifth embodiment of Figure 13 would operate similarly to that explained with reference to the ~low chart of Figure 12. In summary the accelerometer would be used to determine how rapidly the needle accelerates and decelerates and when a hard~r material is hit ..
the structure would accelerat~ or decelerate slower ;j;
under a heaviex load, thereby providing an automated detection of material hardness. The force meter, in ~.' contrast, determines how much force the needle is encountering by how much it is moving. By the detection of how much force is on the needle, one can determine me~hAnical impedance.
Although only a few embodiments have been described in detail above, those having ordinary skill in the art will understand that many ::;
3 0 modif ications are possible in this embodiment without detracting from ~he advan~ages of the invention. ~ll such modi~icakions are intended to be encompassed within ~he following application. .:
, ' :. ' ', ' ~
,;
.
.
, ' :. ' ', ' ~
,;
.
.
Claims (31)
1. A control system for an ultrasonic transducer which includes an aspiration port for operating on a human eye, comprising:
means for monitoring changes in a load encountered by the ultrasonic transducer; and means for controlling an amount of aspiration based on said load changes, and for changing an amount of aspiration to automatically increase when a load on the transducer increases, and changing said amount of aspiration to automatically decrease when the load decreases.
means for monitoring changes in a load encountered by the ultrasonic transducer; and means for controlling an amount of aspiration based on said load changes, and for changing an amount of aspiration to automatically increase when a load on the transducer increases, and changing said amount of aspiration to automatically decrease when the load decreases.
2. A method of controlling an operation in a human eye comprising the steps of:
operating a transducer to conduct said operation; detecting a load presented to the transducer;
determining a relation between a load presented to the transducer with respect to a previous load presented to the transducer;
automatically increasing an amount of aspiration if said load is greater than said previous load; and automatically decreasing said amount of aspiration if said load is less than said previous load.
operating a transducer to conduct said operation; detecting a load presented to the transducer;
determining a relation between a load presented to the transducer with respect to a previous load presented to the transducer;
automatically increasing an amount of aspiration if said load is greater than said previous load; and automatically decreasing said amount of aspiration if said load is less than said previous load.
3. A control system as in claim 1 wherein said monitoring means monitors an electrical impedance of the ultrasonic transducer.
4. A control system as in claim 3 wherein said impedance monitoring means includes means for multiplying current used by said ultrasonic transducer by voltage used by ultrasonic transducer to obtain a value indicative of said impedance.
5. A control system as in claim 1 wherein said aspiration controlling means increases said aspiration amount only when said load change is greater than a predetermined amount, and decreases said aspiration amount only when said load change is less than a predetermined negative amount.
6. A control system as in claim 5 wherein said aspiration controlling means also increases a power applied to said ultrasonic transducer when it increases aspiration and also decreases power to said ultrasonic transducer when it decreases aspiration.
7. A control system as in claim 1 wherein said aspiration controlling means also increases a power applied to said ultrasonic transducer when it increases aspiration and also decreases power to said ultrasonic transducer when it decreases aspiration.
8. A control system as in claim 1 further comprising a speech generating module for producing speech indicative of messages whenever said load changes.
9. A method as in claim 2 wherein said detecting a load step monitors an electrical impedance of said transducer.
10. A method as in claim 2 wherein said detecting step includes detecting a voltage to said transducer, detecting a current to said transducer, and multiplying said voltage by said current to determine a value indicative of said electrical impedance.
11. A method as in claim 2 wherein said amount of aspiration is increased only when said load change is greater than a predetermined amount, and said amount of aspiration is decreased only when said load change is less than a predetermined negative amount.
12. A method as in claim 11 comprising the further steps of increasing power to said ultrasonic transducer when it increases aspiration and also decreases power when it decreases aspiration.
13. A method as in claim 2 comprising the further steps of increasing power to said ultrasonic transducer when it increases aspiration and also decreases power when it decreases aspiration.
14. A method as in claim 2 comprising the further steps of using a speech generator to announce whenever said increasing or decreasing steps are performed.
15. An apparatus for enabling operations on a human eye comprising;
means for applying ultrasound to the eye, including aspiration means for removing particles, produced by said ultrasound, from the human eye;
means for monitoring conditions of said ultrasound applying means, and said aspiration means;
means for producing a voice sound indicative of changes in at least one of said ultrasound applying means and said aspiration means;
means for monitoring changes in a load encountered by said ultrasound applying means, said voice sound produced by said voice-producing means being indicative of said changes in load; and means for controlling an amount of aspiration produced by said aspiration means based on said changes in load.
means for applying ultrasound to the eye, including aspiration means for removing particles, produced by said ultrasound, from the human eye;
means for monitoring conditions of said ultrasound applying means, and said aspiration means;
means for producing a voice sound indicative of changes in at least one of said ultrasound applying means and said aspiration means;
means for monitoring changes in a load encountered by said ultrasound applying means, said voice sound produced by said voice-producing means being indicative of said changes in load; and means for controlling an amount of aspiration produced by said aspiration means based on said changes in load.
16. An apparatus as in claim 15 wherein said monitoring means includes means for detecting a voltage applied to said ultrasound means, means for detecting a current applied to said ultrasound means, and means for multiplying said voltage by said current to obtain a value indicative of said load.
17. An apparatus for operating on a human eye comprising:
means for operating on an area of said eye;
means for aspirating said area during said operation on said eye;
means for determining whether a hardness of said area of said eye in changing; and means for automatically changing an amount of aspiration produced by said aspirating means when said hardness changes by more than a predetermined amount.
means for operating on an area of said eye;
means for aspirating said area during said operation on said eye;
means for determining whether a hardness of said area of said eye in changing; and means for automatically changing an amount of aspiration produced by said aspirating means when said hardness changes by more than a predetermined amount.
18. An apparatus as in claim 17 wherein said operating means is an ultrasonic transducer.
19. An apparatus as in claim 18 wherein said hardness detecting means includes means for determining an electrical impedance of said ultrasonic transducer.
20. An apparatus as in claim 17 further comprising speech generating means for providing speech indicative of said hardness changing.
21. A method of operating on an area of the human eye comprising the steps of:
determining a hardness of said area of said human eye;
determining if said hardness has changed with respect to a previous hardness detected at a previous time;
aspirating said area of said human eye; and automatically changing an amount of said aspiration when said hardness changes by more than a predetermined amount.
determining a hardness of said area of said human eye;
determining if said hardness has changed with respect to a previous hardness detected at a previous time;
aspirating said area of said human eye; and automatically changing an amount of said aspiration when said hardness changes by more than a predetermined amount.
22. A method as in claim 1 wherein said amount of aspiration includes control of an amount of vacuum.
23. A system as in claim 1 wherein said amount of aspiration includes at least one of amount of vacuum and amount of aspiration flow.
24. A control system as in claim 1 wherein said monitoring means monitors a mechanical impedance of the load to determine said changes.
25. A control system for a surgical transducer, which includes an aspiration port, for operating on a human part, comprising:
means for monitoring mechanical impedance of the load to determine changes in characteristics of a load encountered by the surgical transducer; and means for controlling an operating characteristic of said transducer based on said mechanical impedance.
means for monitoring mechanical impedance of the load to determine changes in characteristics of a load encountered by the surgical transducer; and means for controlling an operating characteristic of said transducer based on said mechanical impedance.
26. A system as in claim 25, further comprising a solid state microsensor coupled to said surgical transducer to determine an amount of movement thereof and means for calculating mechanical impedance from said amount of movement and from a power supplied to said transducer.
27. A system as in claim 26 wherein said solid state sensor is a piezoelectric element mechanically coupled to said surgical transducer.
28. A system as in claim 26 wherein said sensor is an accelerometer.
29. A method of controlling an operation in a human body part comprising the steps of;
forming a map between a mechanical impedance of different portions of said body part and a characteristic of a transducer which will conduct the operation which characteristic should be used for said different portions;
operating the transducer to conduct said operation;
detecting a mechanical impedance presented to the transducer;
determining a relation between the mechanical impedance presented to the transducer with respect to a previous load presented to the transducer;
automatically increasing an amount of aspiration if said mechanical impedance is greater than said previous load; and automatically decreasing said amount of aspiration if said mechanical impedance is less than said previous load.
forming a map between a mechanical impedance of different portions of said body part and a characteristic of a transducer which will conduct the operation which characteristic should be used for said different portions;
operating the transducer to conduct said operation;
detecting a mechanical impedance presented to the transducer;
determining a relation between the mechanical impedance presented to the transducer with respect to a previous load presented to the transducer;
automatically increasing an amount of aspiration if said mechanical impedance is greater than said previous load; and automatically decreasing said amount of aspiration if said mechanical impedance is less than said previous load.
30. An apparatus for enabling operations on a human body part comprising:
memory means for storing a map between mechanical impedance of said human body parts and a characteristic to be used in operation for that mechanical impedance;
a transducer, having a characteristic which can conduct the operation on said human body parts;
a mechanical sensor, coupled to said transducer for detecting an amount of movement of said transducer; and processing means for detecting an amount of power provided to said transducer and calculating a mechanical impedance based on said amount of power and said amount of movement and for using said mechanical impedance to address said map to thereby obtain information indicative of said operation and to use said information to control said transducer.
memory means for storing a map between mechanical impedance of said human body parts and a characteristic to be used in operation for that mechanical impedance;
a transducer, having a characteristic which can conduct the operation on said human body parts;
a mechanical sensor, coupled to said transducer for detecting an amount of movement of said transducer; and processing means for detecting an amount of power provided to said transducer and calculating a mechanical impedance based on said amount of power and said amount of movement and for using said mechanical impedance to address said map to thereby obtain information indicative of said operation and to use said information to control said transducer.
31. A system as in claim 30 wherein said map also stores a resonant frequency of various portions of said body part and said processing means further includes means for calculating a current resonant frequency and means for using resonant frequency along with said mechanical impedance to determine said characteristic.
Applications Claiming Priority (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US635,887 | 1991-01-03 | ||
| US07/635,887 US5160317A (en) | 1991-01-03 | 1991-01-03 | Computer controlled smart phacoemulsification method and apparatus |
| US07/810,428 US5279547A (en) | 1991-01-03 | 1991-12-20 | Computer controlled smart phacoemulsification method and apparatus |
| US810,428 | 1991-12-20 | ||
| PCT/US1992/000013 WO1992011814A1 (en) | 1991-01-03 | 1992-01-02 | Computer controlled smart phacoemulsification method and apparatus |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2099780A1 CA2099780A1 (en) | 1992-07-04 |
| CA2099780C true CA2099780C (en) | 1999-05-11 |
Family
ID=27092475
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002099780A Expired - Fee Related CA2099780C (en) | 1991-01-03 | 1992-01-02 | Computer controlled smart phacoemulsification method and apparatus |
Country Status (11)
| Country | Link |
|---|---|
| US (2) | US5279547A (en) |
| EP (2) | EP0565640B1 (en) |
| JP (1) | JP2858949B2 (en) |
| KR (2) | KR100274663B1 (en) |
| AT (2) | ATE168259T1 (en) |
| AU (3) | AU667801B2 (en) |
| CA (1) | CA2099780C (en) |
| DE (2) | DE69226255T2 (en) |
| DK (2) | DK0776643T3 (en) |
| ES (2) | ES2205077T3 (en) |
| WO (1) | WO1992011814A1 (en) |
Families Citing this family (119)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5279547A (en) * | 1991-01-03 | 1994-01-18 | Alcon Surgical Inc. | Computer controlled smart phacoemulsification method and apparatus |
| US5419761A (en) * | 1993-08-03 | 1995-05-30 | Misonix, Inc. | Liposuction apparatus and associated method |
| WO1995020374A1 (en) * | 1994-01-28 | 1995-08-03 | Allergan | Method and apparatus for controlling irrigation and aspiration of fluids during surgical procedures on the eye |
| US5591127A (en) * | 1994-01-28 | 1997-01-07 | Barwick, Jr.; Billie J. | Phacoemulsification method and apparatus |
| US5431664A (en) * | 1994-04-28 | 1995-07-11 | Alcon Laboratories, Inc. | Method of tuning ultrasonic devices |
| US5472447A (en) * | 1994-05-03 | 1995-12-05 | Abrams; Andrew L. | Power-assisted obturator |
| US5913848A (en) | 1996-06-06 | 1999-06-22 | Luther Medical Products, Inc. | Hard tip over-the-needle catheter and method of manufacturing the same |
| US6024725A (en) * | 1996-11-27 | 2000-02-15 | Mentor Corporation | Reducing tissue trauma and fluid loss during surgery |
| US5808396A (en) * | 1996-12-18 | 1998-09-15 | Alcon Laboratories, Inc. | System and method for tuning and controlling an ultrasonic handpiece |
| US7169123B2 (en) * | 1997-01-22 | 2007-01-30 | Advanced Medical Optics, Inc. | Control of pulse duty cycle based upon footswitch displacement |
| US6394974B1 (en) | 1997-01-22 | 2002-05-28 | Allergan Sales, Inc. | Power mode phaco |
| US6780165B2 (en) | 1997-01-22 | 2004-08-24 | Advanced Medical Optics | Micro-burst ultrasonic power delivery |
| US6053906A (en) * | 1997-06-25 | 2000-04-25 | Olympus Optical Co., Ltd. | Ultrasonic operation apparatus |
| US6053886A (en) * | 1997-08-12 | 2000-04-25 | Medtek Devices, Inc. | Switch apparatus for operating an evacuator |
| US5938677A (en) * | 1997-10-15 | 1999-08-17 | Alcon Laboratories, Inc. | Control system for a phacoemulsification handpiece |
| CN1110292C (en) * | 1997-10-16 | 2003-06-04 | 北京中科电气高技术公司 | Cataract ultrasonic emulsifying instrument |
| US6013048A (en) * | 1997-11-07 | 2000-01-11 | Mentor Corporation | Ultrasonic assisted liposuction system |
| US6283974B1 (en) | 1997-11-14 | 2001-09-04 | Aaron James Alexander | Surgical tip for phacoemulsification |
| US6083193A (en) * | 1998-03-10 | 2000-07-04 | Allergan Sales, Inc. | Thermal mode phaco apparatus and method |
| US6986753B2 (en) | 1998-05-21 | 2006-01-17 | Buivision | Constant ocular pressure active infusion system |
| US6028387A (en) * | 1998-06-29 | 2000-02-22 | Alcon Laboratories, Inc. | Ultrasonic handpiece tuning and controlling device |
| US6200326B1 (en) * | 1999-04-28 | 2001-03-13 | Krishna Narayanan | Method and apparatus for hair removal using ultrasonic energy |
| US6179808B1 (en) | 1999-06-18 | 2001-01-30 | Alcon Laboratories, Inc. | Method of controlling the operating parameters of a surgical system |
| US7429258B2 (en) * | 2001-10-26 | 2008-09-30 | Massachusetts Institute Of Technology | Microneedle transport device |
| US6997935B2 (en) * | 2001-11-20 | 2006-02-14 | Advanced Medical Optics, Inc. | Resonant converter tuning for maintaining substantially constant phaco handpiece power under increased load |
| US6908451B2 (en) | 2002-04-25 | 2005-06-21 | Alcon, Inc. | Liquid venting surgical system |
| US7776027B2 (en) | 2002-07-11 | 2010-08-17 | Misonix, Incorporated | Medical handpiece with automatic power switching means |
| US20040092921A1 (en) * | 2002-10-21 | 2004-05-13 | Kadziauskas Kenneth E. | System and method for pulsed ultrasonic power delivery employing cavitation effects |
| US7077820B1 (en) * | 2002-10-21 | 2006-07-18 | Advanced Medical Optics, Inc. | Enhanced microburst ultrasonic power delivery system and method |
| US7316664B2 (en) | 2002-10-21 | 2008-01-08 | Advanced Medical Optics, Inc. | Modulated pulsed ultrasonic power delivery system and method |
| US20040092800A1 (en) * | 2002-11-11 | 2004-05-13 | Mackool Richard J. | System for instructing removal of cataract tissue |
| US6875210B2 (en) * | 2002-11-19 | 2005-04-05 | Conmed Corporation | Electrosurgical generator and method for cross-checking mode functionality |
| US6948503B2 (en) * | 2002-11-19 | 2005-09-27 | Conmed Corporation | Electrosurgical generator and method for cross-checking output power |
| JP2004267462A (en) * | 2003-03-07 | 2004-09-30 | Olympus Corp | Ultrasonic puncture system |
| CA2830583C (en) * | 2003-03-12 | 2015-06-09 | Abbott Medical Optics Inc. | System and method for pulsed ultrasonic power delivery employing cavitation effects |
| JP4126253B2 (en) * | 2003-06-25 | 2008-07-30 | 株式会社ニデック | Ultrasonic surgical device |
| JP2005027907A (en) * | 2003-07-07 | 2005-02-03 | Olympus Corp | Ultrasonic surgery system and probe |
| US7846126B2 (en) * | 2003-07-14 | 2010-12-07 | Abbott Medical Optics, Inc. | System and method for modulated surgical procedure irrigation and aspiration |
| DE102004014666A1 (en) * | 2004-03-19 | 2005-11-17 | Aesculap Ag & Co. Kg | Powered surgical hand tool e.g. drill or circular saw has accelerometer transducer linked to torque limiting system |
| US7651490B2 (en) * | 2004-08-12 | 2010-01-26 | Alcon, Inc. | Ultrasonic handpiece |
| US7297137B2 (en) * | 2004-03-22 | 2007-11-20 | Alcon, Inc. | Method of detecting surgical events |
| US7811255B2 (en) | 2004-03-22 | 2010-10-12 | Alcon, Inc. | Method of controlling a surgical system based on a rate of change of an operating parameter |
| US7625388B2 (en) | 2004-03-22 | 2009-12-01 | Alcon, Inc. | Method of controlling a surgical system based on a load on the cutting tip of a handpiece |
| US7645255B2 (en) * | 2004-03-22 | 2010-01-12 | Alcon, Inc. | Method of controlling a surgical system based on irrigation flow |
| US7572242B2 (en) * | 2004-03-22 | 2009-08-11 | Alcon, Inc. | Method of operating an ultrasound handpiece |
| US7645256B2 (en) * | 2004-08-12 | 2010-01-12 | Alcon, Inc. | Ultrasound handpiece |
| JP4724827B2 (en) * | 2005-03-24 | 2011-07-13 | 国立大学法人山口大学 | Agitation treatment device and catheter |
| US7335997B2 (en) * | 2005-03-31 | 2008-02-26 | Ethicon Endo-Surgery, Inc. | System for controlling ultrasonic clamping and cutting instruments |
| US20070167965A1 (en) * | 2006-01-05 | 2007-07-19 | Ethicon Endo-Surgery, Inc. | Ultrasonic medical instrument |
| US20070173872A1 (en) * | 2006-01-23 | 2007-07-26 | Ethicon Endo-Surgery, Inc. | Surgical instrument for cutting and coagulating patient tissue |
| US20070191712A1 (en) * | 2006-02-15 | 2007-08-16 | Ethicon Endo-Surgery, Inc. | Method for sealing a blood vessel, a medical system and a medical instrument |
| US7854735B2 (en) * | 2006-02-16 | 2010-12-21 | Ethicon Endo-Surgery, Inc. | Energy-based medical treatment system and method |
| US7785336B2 (en) * | 2006-08-01 | 2010-08-31 | Abbott Medical Optics Inc. | Vacuum sense control for phaco pulse shaping |
| US8465467B2 (en) * | 2006-09-14 | 2013-06-18 | Novartis Ag | Method of controlling an irrigation/aspiration system |
| US20080172076A1 (en) * | 2006-11-01 | 2008-07-17 | Alcon, Inc. | Ultrasound apparatus and method of use |
| US8579929B2 (en) * | 2006-12-08 | 2013-11-12 | Alcon Research, Ltd. | Torsional ultrasound hand piece that eliminates chatter |
| US8109937B2 (en) * | 2007-02-23 | 2012-02-07 | Alcon Research, Ltd. | Surgical system for indication of media types |
| US8303530B2 (en) * | 2007-05-10 | 2012-11-06 | Novartis Ag | Method of operating an ultrasound handpiece |
| US20100036256A1 (en) * | 2008-08-08 | 2010-02-11 | Mikhail Boukhny | Offset ultrasonic hand piece |
| US20100094321A1 (en) * | 2008-10-10 | 2010-04-15 | Takayuki Akahoshi | Ultrasound Handpiece |
| US8083691B2 (en) | 2008-11-12 | 2011-12-27 | Hansen Medical, Inc. | Apparatus and method for sensing force |
| US7806865B1 (en) | 2009-05-20 | 2010-10-05 | Alcon Research, Ltd. | Pressurized irrigation squeeze band |
| US8623040B2 (en) | 2009-07-01 | 2014-01-07 | Alcon Research, Ltd. | Phacoemulsification hook tip |
| US8070711B2 (en) * | 2009-12-09 | 2011-12-06 | Alcon Research, Ltd. | Thermal management algorithm for phacoemulsification system |
| AU2014215954C1 (en) * | 2010-07-27 | 2017-06-01 | Alcon Inc. | Mounting arrangement for a pressurized irrigation system |
| US8136779B2 (en) | 2010-07-27 | 2012-03-20 | Alcon Research, Ltd. | Mounting arrangement for a pressurized irrigation system |
| US8784357B2 (en) | 2010-09-15 | 2014-07-22 | Alcon Research, Ltd. | Phacoemulsification hand piece with two independent transducers |
| US10258505B2 (en) | 2010-09-17 | 2019-04-16 | Alcon Research, Ltd. | Balanced phacoemulsification tip |
| CA3064403C (en) | 2010-10-01 | 2022-06-21 | Applied Medical Resources Corporation | Portable laparoscopic trainer |
| US8414605B2 (en) | 2011-07-08 | 2013-04-09 | Alcon Research, Ltd. | Vacuum level control of power for phacoemulsification hand piece |
| US9050627B2 (en) | 2011-09-02 | 2015-06-09 | Abbott Medical Optics Inc. | Systems and methods for ultrasonic power measurement and control of phacoemulsification systems |
| CA2852269C (en) | 2011-10-21 | 2022-02-22 | Applied Medical Resources Corporation | Simulated tissue structure for surgical training |
| CN103987411B (en) | 2011-12-08 | 2018-04-27 | 爱尔康研究有限公司 | The mobile valve components of the alternative in suction and perfusion circuit |
| EP2795604A1 (en) | 2011-12-20 | 2014-10-29 | Applied Medical Resources Corporation | Advanced surgical simulation |
| CN104135957B (en) | 2012-04-20 | 2017-04-26 | 奥林巴斯株式会社 | surgical device |
| US11406415B2 (en) | 2012-06-11 | 2022-08-09 | Tenex Health, Inc. | Systems and methods for tissue treatment |
| US9149291B2 (en) | 2012-06-11 | 2015-10-06 | Tenex Health, Inc. | Systems and methods for tissue treatment |
| EP2880647A1 (en) | 2012-08-03 | 2015-06-10 | Applied Medical Resources Corporation | Simulated stapling and energy based ligation for surgical training |
| CA2885433C (en) | 2012-09-26 | 2023-04-04 | Applied Medical Resources Corporation | Surgical training model for laparoscopic procedures |
| CA2885302C (en) | 2012-09-27 | 2022-08-02 | Applied Medical Resources Corporation | Surgical training model for laparoscopic procedures |
| EP3846151B1 (en) | 2012-09-27 | 2023-11-29 | Applied Medical Resources Corporation | Surgical training model for laparoscopic procedures |
| US10679520B2 (en) | 2012-09-27 | 2020-06-09 | Applied Medical Resources Corporation | Surgical training model for laparoscopic procedures |
| EP3467805B1 (en) | 2012-09-28 | 2020-07-08 | Applied Medical Resources Corporation | Surgical training model for transluminal laparoscopic procedures |
| US9898937B2 (en) | 2012-09-28 | 2018-02-20 | Applied Medical Resources Corporation | Surgical training model for laparoscopic procedures |
| US9486358B2 (en) | 2012-12-17 | 2016-11-08 | Abbott Medical Optics Inc. | Vitrectomy surgical apparatus |
| US9498376B2 (en) | 2012-12-17 | 2016-11-22 | Abbott Medical Optics Inc. | Vitrectomy surgical apparatus with cut timing based on pressures encountered |
| US9271867B2 (en) | 2012-12-17 | 2016-03-01 | Abbott Medical Optics Inc. | Vitrectomy surgical apparatus with regulating of material processed |
| KR102537277B1 (en) | 2013-03-01 | 2023-05-30 | 어플라이드 메디컬 리소시스 코포레이션 | Advanced surgical simulation constructions and methods |
| US9549850B2 (en) | 2013-04-26 | 2017-01-24 | Novartis Ag | Partial venting system for occlusion surge mitigation |
| WO2014186574A1 (en) | 2013-05-15 | 2014-11-20 | Applied Medical Resources Corporation | Hernia model |
| ES2661644T3 (en) | 2013-06-18 | 2018-04-02 | Applied Medical Resources Corporation | Gallbladder Model |
| US10198966B2 (en) | 2013-07-24 | 2019-02-05 | Applied Medical Resources Corporation | Advanced first entry model for surgical simulation |
| WO2015013516A1 (en) | 2013-07-24 | 2015-01-29 | Applied Medical Resources Corporation | First entry model |
| US9757273B2 (en) * | 2013-12-20 | 2017-09-12 | Novartis Ag | Tissue-sensing vitrectomy surgical systems and methods |
| WO2015148817A1 (en) | 2014-03-26 | 2015-10-01 | Applied Medical Resources Corporation | Simulated dissectible tissue |
| CA2946723A1 (en) | 2014-04-23 | 2015-10-29 | Abbott Medical Optics Inc. | Vitrectomy surgical apparatus employing multisensor pressure feedback |
| CA2948617A1 (en) * | 2014-05-12 | 2015-11-19 | Smith & Nephew, Inc. | Closed loop surgical system |
| US9962181B2 (en) | 2014-09-02 | 2018-05-08 | Tenex Health, Inc. | Subcutaneous wound debridement |
| DE102014218583A1 (en) * | 2014-09-16 | 2016-03-17 | Brose Fahrzeugteile GmbH & Co. Kommanditgesellschaft, Würzburg | Monitoring device for an electric machine, control device and method |
| EP3218892B1 (en) | 2014-11-13 | 2019-10-23 | Applied Medical Resources Corporation | Simulated tissue models and methods |
| WO2016134269A1 (en) | 2015-02-19 | 2016-08-25 | Applied Medical Resources Corporation | Simulated tissue structures and methods |
| US9763689B2 (en) * | 2015-05-12 | 2017-09-19 | Tenex Health, Inc. | Elongated needles for ultrasonic applications |
| KR20180008417A (en) | 2015-05-14 | 2018-01-24 | 어플라이드 메디컬 리소시스 코포레이션 | Synthetic tissue structure for electrosurgical training and simulation |
| CA2988767A1 (en) | 2015-06-09 | 2016-12-15 | Applied Medical Resources Corporation | Hysterectomy model |
| EP3323122B1 (en) | 2015-07-16 | 2020-09-02 | Applied Medical Resources Corporation | Simulated dissectable tissue |
| WO2017015438A1 (en) | 2015-07-22 | 2017-01-26 | Applied Medical Resources Corporation | Appendectomy model |
| AU2016329211A1 (en) | 2015-10-02 | 2018-04-26 | Applied Medical Resources Corporation | Hysterectomy model |
| WO2017087746A1 (en) | 2015-11-20 | 2017-05-26 | Applied Medical Resources Corporation | Simulated dissectible tissue |
| US10624785B2 (en) | 2016-01-30 | 2020-04-21 | Carl Zeiss Meditec Cataract Technology Inc. | Devices and methods for ocular surgery |
| ES2946810T3 (en) | 2016-06-27 | 2023-07-26 | Applied Med Resources | simulated abdominal wall |
| AU2018220845B2 (en) | 2017-02-14 | 2023-11-23 | Applied Medical Resources Corporation | Laparoscopic training system |
| US10847057B2 (en) | 2017-02-23 | 2020-11-24 | Applied Medical Resources Corporation | Synthetic tissue structures for electrosurgical training and simulation |
| AU2018261640B2 (en) | 2017-05-04 | 2023-04-27 | Carl Zeiss Meditec Cataract Technology Inc. | Devices and methods for ocular surgery |
| WO2019236615A1 (en) | 2018-06-05 | 2019-12-12 | Carl Zeiss Meditec Cataract Technology Inc. | Ophthalmic microsurgical tools, systems, and methods of use |
| EP3917468B1 (en) | 2019-02-01 | 2023-11-15 | Carl Zeiss Meditec Cataract Technology Inc. | Ophthalmic cutting instruments having integrated aspiration pump |
| EP3968912A1 (en) | 2019-05-17 | 2022-03-23 | Carl Zeiss Meditec Cataract Technology Inc. | Ophthalmic cutting instruments having integrated aspiration pump |
| US11801163B2 (en) | 2019-06-07 | 2023-10-31 | Carl Zeiss Meditec Cataract Technology Inc. | Multi-stage trigger for ophthalmology cutting tool |
| US11877953B2 (en) | 2019-12-26 | 2024-01-23 | Johnson & Johnson Surgical Vision, Inc. | Phacoemulsification apparatus |
| WO2023017334A1 (en) * | 2021-08-07 | 2023-02-16 | Johnson & Johnson Surgical Vision, Inc. | Electronically detecting phacoemulsification tip engagement with a lens |
Family Cites Families (37)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3601126A (en) * | 1969-01-08 | 1971-08-24 | Electro Medical Systems Inc | High frequency electrosurgical apparatus |
| US3812855A (en) * | 1971-12-15 | 1974-05-28 | Surgical Design Corp | System for controlling fluid and suction pressure |
| US3812858A (en) * | 1972-10-24 | 1974-05-28 | Sybron Corp | Dental electrosurgical unit |
| US3902495A (en) * | 1974-01-28 | 1975-09-02 | Cavitron Corp | Flow control system |
| US3930505A (en) * | 1974-06-24 | 1976-01-06 | Hydro Pulse Corporation | Surgical apparatus for removal of tissue |
| US4024467A (en) * | 1974-07-15 | 1977-05-17 | Sybron Corporation | Method for controlling power during electrosurgery |
| US4024866A (en) * | 1974-12-02 | 1977-05-24 | Hydro Pulse Corporation | Surgical apparatus for removal of tissue |
| US3964487A (en) * | 1974-12-09 | 1976-06-22 | The Birtcher Corporation | Uncomplicated load-adapting electrosurgical cutting generator |
| DE2504280C3 (en) * | 1975-02-01 | 1980-08-28 | Hans Heinrich Prof. Dr. 8035 Gauting Meinke | Device for cutting and / or coagulating human tissue with high frequency current |
| SU569308A1 (en) * | 1975-06-27 | 1977-10-24 | Ростовский государственный медицинский институт | Device for ultrasonic surgery |
| US4126137A (en) * | 1977-01-21 | 1978-11-21 | Minnesota Mining And Manufacturing Company | Electrosurgical unit |
| US4184510A (en) * | 1977-03-15 | 1980-01-22 | Fibra-Sonics, Inc. | Valued device for controlling vacuum in surgery |
| US4168707A (en) * | 1977-06-13 | 1979-09-25 | Douvas Nicholas G | Control apparatus for microsurgical instruments |
| US4223676A (en) * | 1977-12-19 | 1980-09-23 | Cavitron Corporation | Ultrasonic aspirator |
| US4496342A (en) * | 1981-03-20 | 1985-01-29 | Surgical Design Corporation | Surge prevention system for an ophthalmic instrument |
| US4590935A (en) * | 1981-11-02 | 1986-05-27 | Optikon Oftalmologia, S.P.A. | Control system for intraocular surgical device |
| DE3378719D1 (en) * | 1983-05-24 | 1989-01-26 | Chang Sien Shih | Electro-surgical unit control apparatus |
| US4508532A (en) * | 1983-09-09 | 1985-04-02 | Ninetronix, Inc. | Ophthalmic aspirator/irrigator and cystotome |
| US4658819A (en) * | 1983-09-13 | 1987-04-21 | Valleylab, Inc. | Electrosurgical generator |
| US4722350A (en) * | 1984-09-21 | 1988-02-02 | Armeniades C D | Ophthalmic instrument for measuring intraocular fluid pressure |
| US4771792A (en) * | 1985-02-19 | 1988-09-20 | Seale Joseph B | Non-invasive determination of mechanical characteristics in the body |
| US4739759A (en) * | 1985-02-26 | 1988-04-26 | Concept, Inc. | Microprocessor controlled electrosurgical generator |
| US4750488A (en) * | 1986-05-19 | 1988-06-14 | Sonomed Technology, Inc. | Vibration apparatus preferably for endoscopic ultrasonic aspirator |
| US4770654A (en) * | 1985-09-26 | 1988-09-13 | Alcon Laboratories Inc. | Multimedia apparatus for driving powered surgical instruments |
| US4712544A (en) * | 1986-02-12 | 1987-12-15 | Castle Company | Electrosurgical generator |
| US4989588A (en) * | 1986-03-10 | 1991-02-05 | Olympus Optical Co., Ltd. | Medical treatment device utilizing ultrasonic wave |
| US4827911A (en) * | 1986-04-02 | 1989-05-09 | Cooper Lasersonics, Inc. | Method and apparatus for ultrasonic surgical fragmentation and removal of tissue |
| US4705500A (en) * | 1986-07-17 | 1987-11-10 | Mentor O & O, Inc. | Ophthalmic aspirator-irrigator |
| US4793346A (en) * | 1986-09-04 | 1988-12-27 | Bruce Mindich | Process and apparatus for harvesting vein |
| US5001649A (en) * | 1987-04-06 | 1991-03-19 | Alcon Laboratories, Inc. | Linear power control for ultrasonic probe with tuned reactance |
| EP0316469B2 (en) * | 1987-11-17 | 1998-11-25 | Erbe Elektromedizin GmbH | High frequence surgical device to cut and/or coagulate biological tissues |
| US5180363A (en) * | 1989-04-27 | 1993-01-19 | Sumitomo Bakelite Company Company Limited | Operation device |
| US5151085A (en) * | 1989-04-28 | 1992-09-29 | Olympus Optical Co., Ltd. | Apparatus for generating ultrasonic oscillation |
| US5139509A (en) * | 1989-08-25 | 1992-08-18 | Site Microsurgical Systems, Inc. | Phacoemulsification system with handpiece simulator |
| US5026387A (en) * | 1990-03-12 | 1991-06-25 | Ultracision Inc. | Method and apparatus for ultrasonic surgical cutting and hemostatis |
| US5279547A (en) * | 1991-01-03 | 1994-01-18 | Alcon Surgical Inc. | Computer controlled smart phacoemulsification method and apparatus |
| WO1992020310A1 (en) * | 1991-05-10 | 1992-11-26 | Ophthalmocare, Inc. | Phaco handpiece providing fingertip control of ultrasonic energy |
-
1991
- 1991-12-20 US US07/810,428 patent/US5279547A/en not_active Expired - Fee Related
-
1992
- 1992-01-02 WO PCT/US1992/000013 patent/WO1992011814A1/en active IP Right Grant
- 1992-01-02 KR KR1019997000718A patent/KR100274663B1/en not_active IP Right Cessation
- 1992-01-02 CA CA002099780A patent/CA2099780C/en not_active Expired - Fee Related
- 1992-01-02 AT AT92904542T patent/ATE168259T1/en not_active IP Right Cessation
- 1992-01-02 JP JP4504427A patent/JP2858949B2/en not_active Expired - Fee Related
- 1992-01-02 DK DK97101751T patent/DK0776643T3/en active
- 1992-01-02 EP EP92904542A patent/EP0565640B1/en not_active Expired - Lifetime
- 1992-01-02 ES ES97101751T patent/ES2205077T3/en not_active Expired - Lifetime
- 1992-01-02 EP EP97101751A patent/EP0776643B1/en not_active Expired - Lifetime
- 1992-01-02 DE DE69226255T patent/DE69226255T2/en not_active Expired - Fee Related
- 1992-01-02 DE DE69233165T patent/DE69233165T2/en not_active Expired - Fee Related
- 1992-01-02 KR KR1019930701926A patent/KR100244122B1/en not_active IP Right Cessation
- 1992-01-02 AU AU12296/92A patent/AU667801B2/en not_active Ceased
- 1992-01-02 DK DK92904542T patent/DK0565640T3/en active
- 1992-01-02 AT AT97101751T patent/ATE246907T1/en not_active IP Right Cessation
- 1992-01-02 ES ES92904542T patent/ES2121007T3/en not_active Expired - Lifetime
-
1993
- 1993-11-08 US US08/148,315 patent/US5520633A/en not_active Expired - Fee Related
-
1996
- 1996-02-19 AU AU45570/96A patent/AU697525B2/en not_active Ceased
- 1996-04-30 AU AU51960/96A patent/AU676980B2/en not_active Ceased
Also Published As
| Publication number | Publication date |
|---|---|
| CA2099780A1 (en) | 1992-07-04 |
| DE69226255T2 (en) | 1998-12-24 |
| ES2205077T3 (en) | 2004-05-01 |
| EP0565640A4 (en) | 1994-03-16 |
| EP0565640B1 (en) | 1998-07-15 |
| DE69233165D1 (en) | 2003-09-18 |
| ATE168259T1 (en) | 1998-08-15 |
| DK0776643T3 (en) | 2003-12-08 |
| EP0565640A1 (en) | 1993-10-20 |
| DK0565640T3 (en) | 1999-04-19 |
| AU667801B2 (en) | 1996-04-18 |
| KR100244122B1 (en) | 2000-03-02 |
| AU697525B2 (en) | 1998-10-08 |
| KR930702922A (en) | 1993-11-29 |
| DE69233165T2 (en) | 2004-06-03 |
| EP0776643A1 (en) | 1997-06-04 |
| AU1229692A (en) | 1992-08-17 |
| ES2121007T3 (en) | 1998-11-16 |
| US5279547A (en) | 1994-01-18 |
| US5520633A (en) | 1996-05-28 |
| DE69226255D1 (en) | 1998-08-20 |
| AU4557096A (en) | 1996-05-23 |
| ATE246907T1 (en) | 2003-08-15 |
| WO1992011814A1 (en) | 1992-07-23 |
| JPH06506125A (en) | 1994-07-14 |
| KR100274663B1 (en) | 2000-11-15 |
| JP2858949B2 (en) | 1999-02-17 |
| AU5196096A (en) | 1996-07-11 |
| AU676980B2 (en) | 1997-03-27 |
| EP0776643B1 (en) | 2003-08-13 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA2099780C (en) | Computer controlled smart phacoemulsification method and apparatus | |
| IE920003A1 (en) | Computer controlled smart phacoemulsification method and¹apparatus | |
| US5733281A (en) | Ultrasound and impedance feedback system for use with electrosurgical instruments | |
| JP5505684B2 (en) | Tonometry device | |
| ATE195410T1 (en) | METHOD AND DEVICE FOR DETERMINING THE DENSITY OF BONE MATERIAL | |
| JPH11309171A (en) | Method and device for optimizing drive of piezoelectric actuator, particularly phacoemulsifier by detecting electromechanical characteristic | |
| JP2002186901A5 (en) | ||
| CN107252312A (en) | Detect the method and portal hypertension monitoring system of portal vein and/or vena hepatica pressure | |
| JPH0337934B2 (en) | ||
| CN107014545A (en) | A kind of divergence expression shock wave energy measuring method based on pressure sensor | |
| JP3643562B2 (en) | Pulse wave velocity measuring device | |
| CN110072472B (en) | Ultrasonic surgical system and method for operating an ultrasonic surgical system | |
| JP2004016746A (en) | Circulatory dynamics evaluation device | |
| JP2006247221A (en) | Pulse wave detector | |
| Hemsel et al. | Resonant vibrating sensors for tactile tissue differentiation | |
| US20040009453A1 (en) | Tooth mobility measuring apparatus | |
| JP2845583B2 (en) | Method and apparatus for measuring mechanical properties of living body surface and structure of vibrator with built-in sensor | |
| Schafer | Characterization of ultrasound surgical devices | |
| EP1052932B1 (en) | Monitoring needle puncture in surgical operations | |
| ATE222372T1 (en) | METHOD AND APPARATUS FOR DETERMINING TRUE AVERAGE PEAK SPEED | |
| JP3802200B2 (en) | Fruit ripeness measuring method and ripeness measuring device | |
| JP2000254104A (en) | Arteriosclerosis level measurement device | |
| RU2247544C1 (en) | Method for controlling ultrasonic liposuction process | |
| JP2004301696A (en) | Hardness measuring instrument for vegetables and fruits equipped with pressure adjusting mechanism and method for measuring hardness of vegetables and fruits | |
| JP2002520078A (en) | Non-contact tonometer for generating non-linear ramp function pressure. |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |