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United States Patent im
[ii] Patent Number: 5,038,756  Date of Patent: Aug. 13,1991
 NEEDLE INTERFACE BOOT FOR
ULTRASONIC SURGICAL INSTRUMENT
 Inventor: Kevin P. Kepley, St. Louis, Mo.
 Assignee: Storz Instrument Company, St. Louis, Mo.
 Appl. No.: 428,523
 Filed: Oct. 30,1989
 Int. CI.* A61B 17/00
 U.S. CI 128/24 AA; 604/22
 Field of Search 128/24 AA; 604/22
 References Cited
U.S. PATENT DOCUMENTS
3,805,787 4/1974 Banko 128/24 AA
4,681,561 7/1987 Hood et al 604/22
4.816.017 3/1989 Hood et al 604/22
4.816.018 3/1989 Parisi 128/24 AA
4,867,141 9/1989 Nakada et al 128/24 A A
4,886,060 12/1989 Wiksell 128/24 AA
Primary Examiner—Lee S. Cohen
Assistant Examiner—John D. Zele
Attorney, Agent, or Firm—David A. Warmbold
A needle interface boot for use in an ultrasonic ophthalmic surgical instrument of the type incorporating coaxial irrigation and aspiration functions which comprises a conically-shaped hollow instrument. The boot is made from a compliant silicone or plastic-type material and is positioned within the irrigation channel surrounding the interface or connection between the vibratory transmissive member or resonator and the needle probe to prevent irrigation fluid from contacting the flat projecting surfaces of this interface and, thus, reduces objectionable cavitation and bubble formation within the irrigation fluid to be delivered to the operative site during use of such a surgical instrument.
4 Claims, 2 Drawing Sheets
NEEDLE INTERFACE BOOT FOR ULTRASONIC
FIELD OF THE INVENTION 5
The present invention relates generally to fluid-irrigated, ultrasonically-operated cutting instruments, and particularly to surgical instruments of the type which employ ultrasonic energy for the emulsification of tissue. This invention especially relates to an ultrasonic 10 needle interface boot surrounding the connection or interface between the transducer and needle probe to improve the operating characteristics of an ultrasonic surgical irrigation-aspiration instrument, such as is used in eye surgery. 15
BACKGROUND OF THE INVENTION
It is now commonly accepted that the vision impairment disease known as cataracts can be alleviated by surgically replacing the natural lens of the eye with an 2C artificial intraocular lens. The condition of cataracts is characterized by the clouding of the natural lens of the eye so that the amount of light which reaches the retina is substantially reduced or completely eliminated.
Surgical instruments utilizing ultrasonic vibrations in 25 combination with the circulation of irrigation liquid over the operative site for the removal of tissue from a biological body are well-known and widely used, particularly in enclosed and substantially enclosed operative sites. Such surgical instruments are particularly 30 well adapted for the removal of cataracts and other surgical procedures performed on the eye. Ultrasonic surgical instruments of the type with which the present invention is primarily concerned employ an elongated probe or hollow needle having an end threadedly at- 35 tached through a vibration transmissive member or resonator to a transducer for supplying ultrasonic energy to the other or free end of the hollow needle. The ultrasonic energy is emitted to dislodge and breakup or emulsify tissue from the operative site for removal by 40 aspiration. Irrigating fluid is delivered through the instrument into a shield, or sheath, surrounding the body of the needle for discharge adjacent to the tip or free end of the needle and is returned by suction through a hollow center in the tubular body of the needle. 45
An ultrasonic surgical aspirator of this type is shown in U.S. Pat. No. 3,805,787 as including conduits for applying suction through the center of the ultrasonically operative needle and for supplying irrigating fluid around the outer surface of the needle through a pas- 50 sage defined by a tubular, shield. The irrigation fluid flows around the free end of the needle element and back through the center of the hollow needle to effectively irrigate and remove the discharged and emulsified tissue. Another such ultrasonic surgical aspirator is 55 manufactured and sold by Storz Instrument Company, Model No. D-8110, located in St. Louis, Miss.
Significant attention in the art for improving the operative characteristics of these instruments for the convenience of the surgeon and to enhance the efficacy of 60 the instrument for the safety of the patient has been directed to solving a number of problems. For example, it has been desired to utilize greater electrical power and circuitry to energize the transducer contained within the ultrasonic surgical instrument to obtain 65 greater excursion or vibratory action of the needle probe. However, such increased power and vibratory action can create cavitation bubbles caused by the ul
trasonically-vibrating member and as a result of directing the irrigating fluid past the vibrating connection or interface between the resonator and needle probe. The needle probes used in these instruments are generally standardized in the industry and typically include a standardized threaded portion at one end for attachment to the resonator or vibration transmissive member and a square shank portion immediately adjacent said threads for receiving a tool for securely attaching the needle probe to the ultrasonic instrument. It is believed that the cavitation bubbles are created in part by the ultrasonic energy being radiated into the irrigation fluid via the sharp angles of the resonator member and needle probe connection or interface site. These cavitation bubbles create a visual obstruction in delicate surgery, and an annoyance in the eye during surgery. Usually the surgeon is required to interrupt the surgery to permit the aspiration system to remove the bubbles before resuming the surgery.
One method of attempting to reduce cavitation bubbles in such an ultrasonic surgical instrument is shown in U. S. Pat. Nos. 4,681,561 and 4,816,017, both entitled "Ultrasonic Decoupling Sleeve". The decoupling sleeve attempts to define a new flow path within the irrigation fluid path existing within the ultrasonic surgical instrument. However, such a decoupling sleeve has been found to be ineffective in reducing cavitation bubbles occurring within such instruments.
Accordingly, it is desired to isolate the resonator/needle probe interface from the irrigation fluid present in the fluid path between the resonator/needle probe structures and the outer shield to avoid cavitation bubbles in the irrigation fluid path of the ultrasonic instrument.
OBJECTS OF THE INVENTION
It is an object of the present invention to improve an ultrasonic surgical instrument of the type described by reducing or eliminating cavitation and bubble formation in the irrigation fluid.
It is a further object of the present invention to provide a Needle Interface Boot (NIB) for an ultrasonic surgical instrument of the type described which reduces or eliminates cavitation and bubble formation with the irrigation fluid.
It is a further object of the invention to provide an improved ultrasonic surgical instrument which avoids the deficiencies of the prior art devices discussed above, and which enables a more efficient, effective and safe use of the instrument for a surgical cataract procedure.
SUMMARY OF THE INVENTION
In accordance with the present invention, an improved ultrasonic surgical instrument is provided of the type having an elongated, generally cylindrical handpiece containing a transducer and vibratory transmissive member or resonator adapted to receive a hollow needle or probe on its free end, an elongated tubular aspiration fluid conduit for sunctioning fluids through the hollow needle and handpiece, and an irrigation fluid supply conduit for supplying an irrigation fluid to the. operative tip of the needle probe. The improvement according to the present invention comprises a component for use in such combination which comprises a generally conically-shaped Needle Interface Boot (NIB) made from a compliant silicone or plastic type material for surrounding the interface or connection