US 3916873 A
An air-permeable, chemically inert valve used to provide an air passage through the tympanic membrane of the ear. A thin layer of porous teflon covers the outer end of a tube lining a passageway created in the tympanic membrane. The porous teflon is impermeable to solids and liquids, but permeable to gases, thereby equalizing the air pressure between the outer and middle ear. An anti-coagulate coating may be applied to the teflon to prevent the tympanic membrane from growing over it.
Description (OCR text may contain errors)
Inventor: Eric I. Wasserman, 6353 Chaffee St., Ventura, Calif. 93003 Filed: Nov. 30, 1973 Appl. No.: 420,412
US. Cl 128/1 R; 3/1; 128/151; A 181/23 Int. Cl? A61B 19/00; A61F 1/18 Field of Search 128/1 R, 350, 151, 152; 3/1; 181/23; 55/417, 523
References Cited UNITED STATES PATENTS United States Patent 1 [111 3,916,873 Wasserman [4 Nov. 4, 1975  VALVE FOR TYMPANIC IVIEMBRANE EAR 3,803,810 4/1974 Rosenberg 55/159 SURGERY 3,807,409 4/ 1974 Paparella et a1. 128/350 R Primary Examiner-Dalton L. Truluck Attorney, Agent, or FirmRichard S. Sciascia; Joseph M. St.Amand; Darrell E. Hollis ABSTRACT An air-permeable, chemically inert valve used to provide an air passage through the tympanic membrane of the ear. A thin layer of porous teflon covers the outer end of a tube lining a passageway created in the tympanic membrane. The porous teflon is impermeable to solids and liquids, but permeable to gases,
13 Claims, 8 Drawing Figures OUTER EAR MIDDLE EAR US. Patent Nov. 4, 1975 MIDDLE EAR OUTER EAR Fig. 40.
0.50 1.60 1.50 2.00 THERMAL CONDUCTIVITY BTU/(HR) (FT (OF/IN) IOO AIR PERMEABILITY METRIC UNITS L60 L50 2.60 DENSITY gm/cc Fig. 49.
0 IO 20 3O 4O 5O 60 WATER ENTRY PRESSURE psi O 5 O 5 O O 7 5 2 E Z x. 632 9 VALVE FOR TYMPANIC MEMBRANE EAR SURGERY- STATEMENT, or GOVERNMENT INTEREST The invention described. herein. may be manufactured andused by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.
BACKGROUND OF THE INVENTION 1. Field of the Invention The presentinvention relates generally to devices used to provide an air passage through the tympanic membrane of the ear and, more particularly, to airpermeable, chemically inert valvesused to provide an air passage through the tympanic membrane of the ear.
'2. Description of the Prior Art Children born with a cleft palate condition exhibit a high likelihood of repeated ear infection as a result of deficiencies involved with the muscles associated with control of the eustachian tube. While medication eliminates the infections, the basic difficulty still remains. Consequently, an alternate, method, based on surgical techniques, is utilized to insert a plastic tube between the middle and outer ear. The surgical procedure, described as a Tympanotomy with Insertion of Tube, is designed to. prevent the production of fluid in the inner ear by,,providing an auxiliary path for air pressure equalization between the middle and outer ear. Normally, the eustachian tube provides an airpath to equalize the air pressure betweenthe middle and outer ear and is controlledby a muscle. When the muscle structure that controls the eustachian tube is deficient, and when infection results in closure of the eustachian tube, an air pressuredifferential develops between the middle and outer ear. The air pressure differential results in the production of fluid, which, if not removed, becomes .increasingly viscous, and ultimately leads to deafness. Surgical procedures are utilized to remove the fluid through an incision in the tympanic membrane, and a plastic collar .assembly is subsequently inserted The Donaldson Silastic Collar, as well as several other similar devices, provide a method of simulating the function of the eustachian tube to equalize the air pressure between the middle and outer car by means of an air passage. However, this, as well as other existing devices also provide a passage for water andsolid particles into the inner ear. Precautions must be taken, particularly in the case of small children, to pr event the entry of water into the ear when bathing or engaging in other activities in and around water.
SUMMARY or THE INVENTION The general purpose of the present invention is to provide a valve. for providing an air passage through the tympanic membrane of the ear which will prevent the passage of solids and liquids, but will allow passage of gases. To obtain this, a specific embodiment of the present invention provides a thin-layer of porous teflon covering the outer end of a tube lining a'passageway created in the tympanic membrane of the ear. The porous teflon prevents the passage of liquids'or solids, but allows the passage of gases through the tube, thereby equalizing the air pressure between the outer and middle ear. An anti-coagulate coating may be applied to the teflon to prevent the tympanic membrane from growing over it.
Accordingly, one object of the present invention is to equalize the air pressure between the middle and outer ear.
Another object of the present invention is to provide a valve that passes gases but does not pass liquids or solids.
Another object of the present invention is to allow persons having valves in their ears to lead normal lives.
Another object of the present invention is to keep water out of the middle ear.
Another object of the present invention is to keep airborne particles out of the middle ear.
Another object of the present invention is to provide a chemically inert valve.
Another object of the present invention is to prevent the tympanic membrane from growing over the valve thereby rendering it useless.
Another object of the present invention is to provide an air-permeable valve.
Another object of the present invention is to equalize gaseous pressure on both sides of a membrane.
Other objects and a more complete appreciation of the present invention and its many attendant advantages will develop as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings in which like reference numerals designate like parts throughout the figures thereof and wherein.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a cross sectional view of the ear.
FIG. 2 is a side view of a specific embodiment of the present invention.
FIG. 3 is a rear view of the specific embodiment of FIG. 2. 1
FIG. 4a through e are graphs of the physical properties of a thin-layer of teflon.
DESCRIPTION OF THE PREFERRED EMBODIMENT .FIG. 1 illustrates the ear. Outer car is terminated ;by tympanic membrane 16 Eustachian tube 104 serves to equalize the air pressure between outer ear 100 and middle ear 102.
Turning now to FIG. 2, valve 10 comprises a tube 12 having a notch 14 midway between the two ends of tube 12. Notch 14 extends around the entire circumference of tube 12. Tympanic membrane 16 grows into notch 14. A passageway 18 extends through tube 12 along its longitudinal axis. A thin-layer of material 20 is affixed to and covers one end of tube 12. Valve 10 is a silastic collar with thin'layer 20 attached thereto. It is noted that valve 10 of FIG. 2 is not drawn to scale. Tube 12 is a chemically i-nert means for lining a passageway through tympanic membrane 16. Tube 12 serves as a conduit. Tube. 12 may be made of silicon rubber or any other suitable chemically inert material that the body will not reject. It is noted that there are many different devices of varying shapes and sizes similar to tube 12 currently in medical use designed for stability in the ear. A common characteristic of all such devices is a passageway through them.
Thin-layer 20 is impermeable to solids and liquids, but permeable to gases. Thin-layer 20 is, also, chemically inert thereby restricting rejection by the body.
There are a number of materials currently available with such properties including a number of metals and plastic foams which are chemically. inert,v airpermeable, and liquid and solid impermeable. Sintered stainless steel and sintered brass are two such metals.
In addition, porous teflonplastic may be utilized. Thinlayer 2 is bonded to tube 12 using a chemically inert glue or other means. Thin-layer may bemade of a porous teflon material being 2.54 X 10," cm thick (0.001 inch), having a density of 0.1 gram per cubic.
centimeter, and water entry pressure of vnominally 2 pounds per square inch. It is noted that thin-layer. 20 may be attached to either end/of tube ,12 or anywhere in passageway 18 the only requirement being that thinlayer 20 completely cover a cross sectional area of passageway l8.
FIG. 4a through 4e graphically illustrates the physical properties of a porous teflon material. FIG. 4a graphicallyillustrates porosity vs. density. FIG. 4b graphically illustrates porosity vs. airpermeability, FIG. 4 c graphically illustrates porosity vs. thermal conductivity. FIG. 4d graphically illustrates porosity vsQsize of largest pores. FIG. 4e graphically illustrates porosity. vs. water enter pressure. Line illustrates thespecitic properties of a t eflonmaterial satisfactory for use asthin-layer 2 0. It is noted that the material of thinlayer 20 is selectable for awide variety of conditions that allow the optimization of pressure differentiaLair-flow rate and solidand-liquid-impermeable, chemically ine rt material such as teflon. That is, t'ube 12 and thin-layer 20 may be one piece'thereby eliminating the need for bonding discussed supra.
Obviously, numerous modifications and variations of the present invention are possible in the light of the above teachings. It is'the're foreto be understood that "within the scope of the appended claimsthe invention may be practiced otherwise than as specifically described hereinQi" I I a i I claim: I v 1. A gas-permeable, chemically inert valve adapted for insertion in the tympanic membrane of the car comprising:
a. a chemically inert tubular member adapted for lining a passageway through a t y mpanic membrane having 'ari external surface'thereon, said external surface having a portion thereof intermediatethe ends of said tubular member about which said tym- 1 panic membrane grows, said tubular memberha'ving a first opening located at one end thereof and a second opening located at the other end thereof; and I --"outer ear is. equalized, wh'ilesimultaneously' preventing any passage of liquids or solids therethrough. i 2. The valve of'claim l fixed to said firstopening.
3. The valveof claim lwherein said covering means is affixed to said second opening; 2
4. The valve of claim 1 wherein said tubular member has means about the circumference thereof into which said tympanic'membrane grows for retaining said tubular member in said tympanic membrane.
-5. The valve ofclaim 4 wherein said tubular member has a notch around its circumference intowhich the tympanic membrane grows. l i
' 6. The valve of claim 1 wherein said tubular member "is fabricated from a-gas-permeable', solid-and-liquid impermeable, chemically inert material.
7. The valve of claim l wherein said covering means is 'a thin-layer of material made of teflon.
'- 8. The valve of claim 1 wherein said covering means is a thin-layer of material made of sintered stainless st el. 9. The valve of claim 1 wherein said covering means is a thin-layer of material made of sint'eredmetal.
10. The valve of claiih l 'wherein said covering means is a thin-layer'of material .001 inch thick, having a water entry pressure of 2 pounds per square inch'an a density of 0.1 gram per. cubic centimeter; I
' 11. The valve of claim 1 further comprising'an anticoajgulating'coating covering said chemically inertcoveringmeans whereby said tympanic membrane is preventedfrom growing over said coveri'n gm e'ansl 12.- A'method of equalizing the gas pressiire between the middle ear and the outer ear-'utilizin'g'avalve assembly which simulates the eustachian tube function of the ear while preventing the inadvertent passage of both solids and liquids including water, but allowingthe passage of gases through the tympanic membrane comprising:
a.'surgically creating a passageway in the tympanic membrane; i
b. inserting said Valve assembly which incorporates a solid and liquid impermeable but gas permeable, chemically inert membrane into said passageway; r 7
cf allowing the tympanic membrane to'grow around said'valve assembly. 13. The method of claim 12,- wherein immediately following the step of inserting and immediately preceding the step of allowing, a further step is inserted comprising coating said gas-permeable, chemically inert wherein said covering is af-