US3436763A

US3436763A - Orbital implant of fused acrylic plastic and process of implanting

Info

Publication number: US3436763A
Application number: US538096A
Authority: US
Inventors: Albert T Milauskas
Original assignee: ALBERT T MILAUSKAS
Current assignee: ALBERT T MILAUSKAS
Priority date: 1966-03-28
Filing date: 1966-03-28
Publication date: 1969-04-08
Anticipated expiration: 1986-04-08

Description

April 8, 1969 A. T MILAUSKAS V ORBITAL IMPLANT OF FUSED ACRYLIC PLASTIC 1 AND PROCESS OF IMPLANTING Filed uarcn 2a, 1966 INVENTOR. ALBERT T. MILAUSKAS ATTOR NE YS April 8, 1969 A. T. MILAUSKAS 3,435,763

QRBITAL IMPLANT OF FUSED ACRYLIC PLASTIC AND PRQCESS OF IMPLANTING Filed March 28, 1966 Sheet 2 of 2 m: 4 F/G. 5 34 INVENTOR. ALBERT T. Ml LAUSKAS BY 49., J am a, fl k ATTORNEYS ORBITAL IMPLANT 9F FUSED ACRYLIC PLASTIC AND PROCESS OF IMPLANTHNG Albert T. Milauskas, Baltimore, Md.

(1984 Newman Drive, Trenton, Mich. 48183) Filed Mar. 28, 1966, Ser. No. 538,096 Int. Cl. Hlf 1/16 U.S. Cl. 3-13 8 Claims ABSTRACT OF THE DISCLOSURE An orbital implant for human eye prosthesis formed from an acrylic plastic and composed of a body and cover portion wherein the body portion has a plurality of mounds adapted to be fusibly engaged within complementary shaped depressions of the cover portion.

This invention relates to orbital implants which are utilized in the correction and/or replacement of injured or defective eyes. More particularly, this invention relates to a new and novel orbital implant formed from an acrylic resin which can be simply and easily permanently attached to and positioned within muscular structure of the human eye.

Orbital implants are utilized in connection with a conformer or prosthetic eye for forming artificial eyes or replacing human eyes. These implants are provided so as to give the prosthetic eye good mobility so that it resembles a natural eye. It is an essential nature of the orbital implant that it be permanent, i.e., for the, life of the patient, so that the patient need only suffer one operation to correct damage done to the eye or to insert an artificial eye. While many orbital implants have been developed for correcting damage done to the eye or for inserting an artificial eye, it has been found that many defects occur, especially after use over a long period of time.

One of these defects is caused by the fact that many of these implants are made from substances that produce appreciable tissue reaction or destruction especially over a period of many years. Additionally, many of the substances from which the orbital implants were constructed formed after a long period of time, rough surfaces causing pressure points to arise within the eye producing erosion of the conjunctive tissue. Other problems which arise with respect to these implants relate to the design of the implant. The implant should be designed so that that ocular muscles can be permanently and tightly secured within the orbital implant even when the implant is rotated. While in previous designs of orbital implant, the ocular muscles have been secured tightly with the orbital implant during the initial placement of the implant in the eye, considerable loosening of the muscles occurred after a short period of use. This produced a tendency in the anterior surfaces of the implant to rotate posteriorly in such a way that tissue damage and extru sion of the implant occurred. It was found that this loosening of the muscles within the interior or from the anterior surface of the implant was caused by either faulty design or faulty construction of the implants themselves. Various orbital implants have been constructed of two different substances, such as a solid posterior section and a sponge anterior part. In this case the two parts are cemented together and the ocular muscles are attached to the anterior surface of the implant. These types of implants have proven to be defective due to the fact that the cements utilized have deteriorated after many years, causing separation of implant parts and subsequent extrusion of the implant. Therefore, it had long been desired to develop an orbital implant wherein the need for cementing of the parts together to encase the muscles within the implant can be eliminated.

Another disadvantage in the use of many of the wellknown orbital implants is that these orbital implants are of such a complex design that the surgical operation needed to position the orbital implant within the ocular muscles has been very complicated. As in many cases, operations involving the insertion of orbital implants within the eye cavity have involved the services of a physician and at least two assisting doctors. Therefore, it has long been desired in the art to provide an orbital implant of such a construction that it will make it easy to insert in the cavity of the eye without utilizing the services of many assisting physicians.

It is the object of this invention to provide an orbital implant for the correction of injured or defective eyes or the insertion of artificial eyes which will remain permanently within the cavity of the human eye for the lifespan of a patient without the need of the patient undergoing subsequent operation to correct the nature of the implant.

It is the object of this invention to provide an orbital implant of such a construction so that it will be permanently fixed within the cavity of the human eye and can rotate within the eye cavity without danger of the ocular muscles which are retained and encased therein loosening and migrating after a long period of use.

It is the further object of this invention to provide an orbital implant of such a construction that its parts can be secured together so as to encase the ocular muscles therein without the use of an adhesive or cement.

It is the further object of this invention to provide an orbital implant formed from such a material which will produce no appreciable tissue reaction or destruction even after a period of many years.

It is the further object of this invention to provide an orbital implant wherein the ocular muscles are tightly secured so that the implant has good mobility coupled with little tendency of its anterior surface to rotate posteriorly in such a way that tissue damage or extrusion can occur.

It is the further object of this invention to provide an orbital implant that can be inserted and secured within the cavity of the human eye by means of a simple operation without the necessity for utilizing assisting physicians during the operation.

In accordance with this invention the orbital implant which is used in connection with a prosthetic eye contains a body portion and cover portion, both formed from an acrylic resin, which are fused together by means of a volatile organic solvent capable of dissolving the acrylic resin which forms the implant. The body portion of this implant has an approximately semi-circular rear section with a plurality of individual mounds protruding forwardly from said rear section and terminating in an upper surface. These mounds are spaced apart a proper distance so as to be able to accommodate between them the severed ends and a portion of the bodies of the four rectus muscles. The cover section has a rear face provided with a plurality of depressions equal in number to the mounds and having a complimentary shape to the upper surface of the mounds of the body section so that it can engage the upper surface and be fused thereto by means of a volatile organic solvent capable of dissolving said acrylic plastic.

It has been found that by utilizing acrylic plastic materials in forming the orbital implant by fusing with a volatile organic solvent capable of dissolving the acrylic resin, the rectus muscles which are secured between the mounds in the body section can be encased within the orbital implant so that the orbital implant will be permanently secured and can rotate within the cavity of the eye without any danger of the rectus muscles loosening over a prolonged period of time. Furthermore, by encasing the muscles in this manner the orbital implant is secured in the eye cavity so that extremely good mobility of the implant is provided Without the danger of migration or extrusion of the muscles due to swelling or late hemorrhaging. Additionally, the implant is provided with good mobility without any tendency of the anterior surface of the implant rotating posteriorly in such a way that tissue damage or extrusion is caused. Also, by fusing the cover portion to the body portion of the implant by means of a 'volatile organic solvent capable of dissolving an acrylic resin, the cover and body portions of the implant are permanently united as if formed from one surface without any danger of these portions separating after prolonged periods of time. This permanent uniting, it has been found, can only occur when the portions of the orbital implant are fused by means of a volatile organic solvent capable of dissolving an acrylic resin and not by bonding these portions together by means of a cement or an adhesive. Also, by the use of this method of uniting, any necessity for providing an enlarged cover portion with cavities which engage and clamp the mound into securement therewith, is eliminated.

The foregoing objects and advantages of this invention will more fully appear from the following description made in connection with the accompanying drawings wherein like reference characters refer to similar parts throughout the several views and in which:

FIG. 1 an exploded perspective vie-w of the component parts of the orbital implant of this invention;

FIG. 2 is a cross-sectional view of the assembled orbital implant of this invention having the rectus muscles encased therein;

FIG. 3 is a cross-sectional view of the orbital implant along line 4-4 of FIG. 2;

FIG. 4 is a front view showing the implant body portion held by the traction sutures above the muscle cone of the eye cavity with the semi-circular surface of the implant body toward the apex of the muscle cone and with both the sutures from each rectus muscle being pulled apart;

FIG. 5 is a similar view showing the superior and inferior rectus muscle and the medial and lateral rectus muscles overlapped in the accommodating recess or channels formed in the body portion of the implant and solvent being applied to the grooves in the upper surfaces of the mounds;

FIG. 6 is a front view of the cover portion having solvent applied to the projection formed in its depression;

FIG. 7 is a similar view of that of FIG. 5 showing the cover portion being placed over the body portion of the orbital implant;

FIG. 8 is a similar view to FIG. 7 showing the conjunctiva enclosed and secured by sutures.

Referring now to the embodiment of the present invention illustrated, the essential implant of this invention consists of a body portion 10 and a cover portion 12. The essential implant body 10 is basically in the form of a hemisphere of a diameter usually approximately 18 mm. with a maximum axial dimension from the posterior center of the body to the outer surface defined by the forward tip portions of the mound 14 approximating 12 mm. The cover 12 of the implant is a smooth flat disc, with beveled edges having the thickness of about 2 mm. It will, of course, be understood that both larger and smaller sizes may be utilized, depending upon the specific prerequisite of the patient.

Both the cover portion 12 and the body portion 10 are made of an acrylic polymer or plastic such as polymethyl methacrylate, polyethyl methacrylate, polymethyl ethacrylate, and polyethyl ethacrylate. Any of the conventional polymerization products of esters of acrylic acid or esters of methacrylic acid can be utilized as the body and cover portion of the orbital implant of this invention. It has been found that these acrylic resins form an orbital implant having a smooth surface thereby eliminating the formation of rough surfaces or specific pressure points which are present after long periods of use, when the implant is constructed from other materials. The smooth surfaces presented by these resins provide a more equal distribution of pressure, so that conjunctival erosion which occurred with materials having slightly rough surfaces, is eliminated. In addition, these acrylic plastics are inert so that they produce no appreciable tissue reaction or destruction even after many years of use.

The forward or anterior portion 11 of the body 10 provided with a plurality of circumferentially spaced mounds or projections 14 which as shown in the embodiment illustrated, are four in number and are integrally formed with the body proper.

The forward or anterior portion of the body between said mounds provides a cross shaped, preferably slightly concaved surface 16 for receiving the several rectus muscles of the human eye together with the skin or fabric of the Tenons capsule and of the conjunctiva as will later be more specifically described. The mounds 14 are circumferentially spaced on the concave surface 16 so that two

spaces

17 and 17a, each extending throughout the entire length and width of the surface 16 are provided. The

spaces

17 and 17a cross each other at right angles on the anterior surface 16 of the implant body 10.

Spaces

17 and 17a provide means for retaining the superior and inferior rectus muscles 18 and the medial and lateral rectus muscles 19, which are shown in FIG. 4, within the body of the implant, so that the horizontal and vertical rectus as well as the inferior and superior rectus muscles can be permanently secured in that position after the cover 12 has been fused to the body 10 of the implant.

Each of the mounds or projections 14 terminate in an upper surface 13, which, as shown in FIG. 1 is relatively flat. Within each of the upper surfaces 13, there are disposed grooves 15 which are located at the center portion of the flat surface 13. These grooves 15 extend transversely across the center section of the surface 13.

Closely cooperating with the body 10 of the implant of this invention is a specifically formed cover 12 having a generally convexed anterior surface and having a posterior recess portion provided with four circumferentially spaced recesses 22 shaped complementary to the upper surfaces 13 of the mounds 14. Each of the recesses 22 has a projection 24 extending transversely across the center section of the recesses and shaped complementary to a respective groove 15 on surfaces 13 of the mounds or projections 14. As shown in FIG. 3, the projection 24 is adapted to be frictionally and snugly engaged Within the grooves 15 of the surfaces 13.

Prior to the orbital implant being assembled by placing the surfaces 13 of the mounds 14 within their complementary recesses 24 of the cover 12 so that the projections 24 fit into the grooves 15, a volatile organic solvent is placed into the grooves 15 and on projections 24. The volatile organic solvent which is placed into the grooves 15 and the projections 24 should be an organic solvent capable of dissolving the acrylic resin from which the implant is constructed. In this manner when the projections 24 are placed within the groove 15, the acrylic plastic of groove 15 and the projection 24 will liquidify and unit so as to form a unitary fused structure. In producing this fusion, all that is needed is a few drops of the solvent. It has been found that when this solvent is applied to the surfaces of the plastic material, it dissolves these surfaces and then evaporates so that a molecular fusion occurs between the surfaces to which it is applied.

In producing the fusion between the cover portion 12 and the body portion 10 of the orbital implant, any conventional volatile organic solvent capable of dissolving an acrylic resin can be utilized. Generally, it is preferred to utilize methylene chloride due to the fact that it is inexpensive and its properties are most compatible with surgery. However, any conventional volatile liquid organic solvent for an acrylic polymer can be utilized, such as: methylene chloride, chloroform, carbon tetrachloride, ethyl chloride, ethylene chloride, ethylidene chloride, tetrachloroethane, vinyl chloride, tetrachloroethylene, acetone, ethyl methyl ketone, methyl propyl ketone, butyl methyl ketone, isobutylmethyl ketone, methyl isobutenyl ketone, cyclohexanone, methyl cyclohexanone, isophorone, ethyl ether, isopropyl ether, dioxane, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, amyl acetate, sec-amyl acetate, Cellosolve, benzene, toluene, methanol, ethanol, butyl acetate, monomers of methyl or ethyl methacrylate.

Generally it is preferred that these solvents have a boiling point of less than about room temperture. Furthermore, the lower the boiling point of the solvent is, the better it is adapted to be utilized as the fusing medium, since the less time it takes to evaporate from the surface of the acrylic plastic during the operation. In this manner fusion of the cover and the body section can be accomplished quickly and easily.

The body section of the implant is provided with two oppositely and parallel disposed tunnels 25 and 25' which are positioned within the anterior portion 11 of the body section. The

channels

25 and 25 extend from one end of the anterior portion 11 of the body section 10 to the other end of anterior portion. These parallel channels are provided for the reception of sutures for supporting the implant temporarily during the implantation surgery.

A method whereby the orbital implant of this invention can be inserted into the cavity of the eye is shown in FIGS. 4 through 8. The implant in use is completely buried in the cavity of the eye with the anterior portion thereof being covered by Tenons capsule and conjunctiva. In the surgical technique, before the enucleation of the eye, the implant is carefully sterilized and silk traction satures 30 are threaded through the channels 25 and 25'. The conjunctiva and Tenons capsule are incised as close to the cornea of the eye to be removed as possible and the muscle insertions are exposed. The cut ends of the conjunctiva and Tenons capsule 36 are then spread apart and away from the eye.

The rectus muscles are then sectioned and held apart by

clamps

37 and 38, care being taken not to cut the applied sutures, nor to cut Tenons capsule in any undesirable manner.

The implant with the sutures 30 is then positioned within the Tenons capsule and these sutures are wrapped around screw 33 of an Iliff 34 or similar lid speculum as shown in FIG. 4 so as to prevent the implant from drooping too deeply into the muscle cone. The screw 33 0f the Iliff 34 acts as a guide for placing the implant within the eye cavity. As seen in FIG. 5, the superior and inferior rectus muscles 18 and the lateral and medial rectus muscles 19 are next embricated in the

respective spaces

17 and 17a by any conventional means. One method of securing the inferior and superior rectus muscles in overlapping rela tionship across the front of the body 10 of the implant and within the

spaces

17 and 17a is by applying sutures to both the inferior and superior muscles and passing the arm of the suture in the inferior rectus muscle underneath and through the superior rectus muscle. The two muscles are tied to each other across the center saving one arm and cutting the other. Each arm of the suture in the superior rectus muscle may be passed, one around its nearby edge of the inferior rectus muscle, and up through from its underside then continuously through the end of the superior rectus muscle and the tWo tied to each other across the end of the superior rectus muscle, saving one arm and cutting the other. The same procedure is performed on the medial and lateral rectus muscles. In this manner these rectus muscles are very nicely accommodated and contained in the channel portions of the

crossshaped space

17 and 17a between the appropriate mounds 14.

After the rectus muscles are sutured and wrapped within the

spaces

17 and 17a, two or three drops of the solvent applied to each of the grooves 15 by means of an injection needle 40. As seen in FIG. 6, the solvent is also applied to the projections 24 within the depressions 22 of cover 12 by means of the needle 40. While FIGS. 5 and 6 show the application of the solvent to the cover andbody portion of the orbital implant by means of a hypodermic needle, it is apparent that any conventional means to apply the solvent can be utilized in accordance with this invention.

After the solvent has been applied to both the cover and the body portion of the implant, the cover portion is lifted and placed over the mounds 14 of the body portion 10. As shown in FIG. 7, gentle finger pressure is applied for one or two minutes to the cover 12 so as to achieve a solid fusion between the cover and the implant body. This fusion can take place within a few seconds after the application of pressure depending upon the solvent utilized. In this manner the rectus muscles become permanently encased within the body section of the orbital implant.

After the cover has been fused to the body section of the implant, the sutures 30 are loosened by readjusting the screw 33 on the Iliff speculum 34. In this manner the orbital implant is lowered into the eye cavity. The traction sutures are then cut and pulled out of the channels 25 and 25' so that the implant is allowed to recede into the eye cavity. As shown in FIG. 8, the Tenons capsule and conjunctiva are then closed b a carefully calculated modified purse string suture formation 45.

After the conjunctiva has been closed, a conformer is ready to be fit into the lid of the eye. Any conventional conformer can be utilized in accordance with the orbital implant of this invention. However, it is generally preferred to utilize a conformer formed from an acrylic plastic. Generally, the conformer should have a continuously smooth and nicely rounded marginal edge at both anterior and posterior. Posterior marginal edge should contact and apply pressure to the tissues imposed upon the anterior of the implant and upon the peripheral anterior portion of the socket and tissues thereof. The anterior marginal edge in post-surgical use distends and engages with the underside of the eyelids providing substantially the same contour and contact as the exposed marginal scleral of a natural eye. The final eye or prosthesis which is fitted approximately after about a month following implantation is generally based upon the shape of the conformer or upon slight modification of conformer for those patients who cannot afford a custom-type fitting. Preferably, an impression is taken of an anterior of the implant with Tenons capsule and conjunctiva closed thereover. Such impression is translated into a wax model for the prosthesis and then altered for best psychological or cosmetic results.

The post-surgical conformer conforms to the anterior portion of the socket and to the undersides of the eyelids. It holds the lids in normal condition and assists in molding the tissues of the conjunctiva Tenons capsule and tissues in the anterior part of the eye socket.

From the foregoing description, it will be seen that by means of this invention a comparatively simple, scientific and highly efiicient orbital implant is provided which substantially facilitates surgery and conformance of an artificial eye in the enucleated socket. This is seen by the fact that the space in between the mounds which are provided at the body section of the orbital implant are ideally suited for embricating the rectus muscles since the rectus muscles can be overlapped with ease within the grooves without placing undue tension on them when they are sutured. Furthermore, by means of this invention the rectus muscles are encased within the implant and not merely tied over or on to it. In this matter, migration and extrusion due to swelling or late hemorrhage is prevented. Furthermore, encasing of the rectus muscles allows for strictly good mobility of the implant and prosthesis.

What is claimed is:

1. An orbital implant for use in connection with human eye prosthesis comprising a united cover portion and body portion each being formed from an acrylic plastic, said body portion having rear section and a plurality of individual mounds protruding forwardly from said rear section, each of said mounds terminating in an upper surface, said mounds being spaced apart a proper distance to accommodate between them the severed ends and a portion of the bodies of the rectus muscle, said cover portion having a rear face provided with the plurality of depressions equal in number to said mounds and of a complimentary shape to the said upper surfaces, said upper surfaces engaging and being fused to said depressions by means of a volatile organic solvent capable of dissolving said acrylic plastic.

2. The orbital implant of claim 1 wherein said body section contains two parallel channels within said rear section, said channels extending across the entire rear section.

3. The orbital implant as claimed in claim 1, wherein each of said upper surfaces are fiat and have a central groove extending throughout the upper surfaces, each of said depressions having a projection of complementary shape to said groove fitting into each of said grooves, each of said projections being fused to the body portion within each of the grooves by means of a volatile organic solvent capable of dissolving said acrylic resin.

4. The orbital implant of claim 3, wherein said volatile solvent is methylene chloride and said acrylic resin is polymethyl methacrylate.

5. The orbital implant of claim 3, wherein said body portion contains two parallel channels disposed within said rear section, said channels extending throughout the entire rear section.

6. A process of implanting an orbital implant formed entirely of an acrylic polymer in the cavity of the eye comprising:

(a) severing and spreading the Tenons capsule and conjunctiva and rectus muscles of the eye to form a cavity,

(b) inserting the body section of an orbital implant wherein the body section contains a rear section and a plurality of spaced individual mounds protruding forwardly from said rear section and terminating in an upper surface while said Tenons capsule, conjunctiva, and rectus muscles are spread apart,

(0) accommodating the ends and a portion of the body of the rectus muscles within the space between the mounds and thereafter tying the ends of the rectus muscles together,

(d) providing a cover section for said body portion, wherein the cover section has a rear face provided with a plurality of depressions equal in number to said mounds and having a complimentary shape to said upper surfaces as to engage said upper surface,

(e) applying a organic volatile solvent capable of dissolving the acrylic polymer which form the body and cover portion of said implant in the upper surfaces of said body section and in the depressions of said cover section,

(f) placing the cover section on said body section so that the depressions of said cover section engage the upper surfaces of the mounds of the body portion,

(g) evaporating said solvent and allowing said upper surfaces to unite with said depressions so as to fuse said body portion to said cover portion, thereby encasing the rectus muscles within said cover and body portion, and

(h) suturing the conjunctiva and Tenons capsule so as to enclose the orbital implant within the cavity of the eye.

7. The process of claim 6, wherein both the body and cover section are formed from polymethyl methacrylate and the solvent is methylene chloride.

8. The process of claim 6, wherein each of said upper surfaces of said mounds are fiat and have a groove extending throughout the upper surface, each of said depressions in said cover section have a projection of complementary shape so as to fit into each of said grooves, applying said solvent to the projections and grooves and placing said cover section on said body portion so that each of the projections are fitted into each of said grooves.

References Cited UNITED STATES PATENTS 2,516,804 7/1950 Rolf et a1. 3l3 2,649,590 8/1953 Cutler 3--13 2,792,573 5/1957 Clarke et a1. 3-13 3,070,808 1/1963 Allen 313 RICHARD A. GAUDET, Primary Examiner.

RONALD L. FRINKS, Assistant Examiner.