Improved Prosthetic Motility Following Enucleation WILLIAM R. NUNERY, MD, KATHY J. HETZLER

Abstract: Enucleation is the beginning of a long-term relationship between the ophthalmologist and the patient to provide a comfortable, cosmetically acceptable, anophthalmic socket. The ideal socket should have a low risk of implant extrusion, normal volume, and normal motility of the prosthesis. Aspheric motility implants provide good motility, but pressure points between implant and prosthesis may lead to discomfort or extrusion. Spherical volume implants minimize pressure between implant and prosthesis, but have been criticized for inability to transmit motility to the prosthesis. The authors describe a mod­ification of the traditional sphere implant technique that provides improved motility, ease in prosthetic fitting, and a comfortable socket. [Key words: an­ophthalmic socket, autogenous cartilage graft, enucleation, ocular prosthesis, orbital implant, preserved scleral graft, spherical implant.] Ophthalmology 90: 1110-1115, 1983

The long-term objectives for anophthalmic patients are to provide a comfortable socket, avoid implant extrusion, and maximize prosthetic motility.

At the time of enucleation the surgeon can determine the long-term prognosis by (1) enucleation technique and (2) choice of orbital implants. After enucleation, custom fitting of the prosthesis with modified impression tech­nique is necessary for optimal transmission of motility to implant and comfort of prosthesis wearing. In this paper we shall discuss a modification of the spherical implant enucleation technique and its advantages for the an ophthalmic socket.

The aspects of initial surgical technique that should be considered by the surgeon are (1) to replce adequate vol­ume loss; (2) to provide optimal treatment of Tenon's fascia to minimize chance of implant extrusion; (3) to replace muscles for optimal motility; and (4) to preserve the fornices to allow adequate support and fitting for the prosthesis.

Implants from which to choose are (1) integrated im­plant (not in common usage today); (2) irregularly sur­faced motility implants, such as the Allen implant, Iowa implant, Mesh implant, and SolI implant; and (3) sphere implant.

From the Department of Ophthalmology, Indiana University, Indianapolis, Indiana.

Reprint requests to William R. Nunery, MD, Department of Ophthalmology, Indiana University, 702 Rotary Circle, Indianapolis, IN 46223.

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Previously used integrated implants contain an exposed portion, projecting from the socket, that fits the prosthesis in a lock-and-key fashion. While these implants resulted in excellent motility, the extrusion rate, potential for in­fection, and socket discomfort have made the integrated implants impractical for use. A variety of irregularly sur­faced motility implants are now in popular use. The most popular of these is the Iowa implant (Fig 1). I

The irregularly surfaced implants operate by trans­mission of extraocular muscle movement directly to the implant, and secondarily to the prosthesis. Extraocular muscles are attached directly to the implant. As the im­plant moves, irregular projections on its front surface engage the prosthesis and push with direct pressure through overlying conjunctival tissue (Fig 2). The greater the direct pressure, and the tighter the fit between implant and prosthesis, the better the motility. The disadvantage of this direct pressure system is that it leads to pressure points between the irregular surface and prosthesis, be­tween which the conjunctiva is pinched. This may result in an uncomfortable socket with potential for extrusion through the pressure points (Fig 3).

In 20 patients referred during a 2-year period specifically for extruding implants, eight of these were Allen implants, six were Iowa implants, four tantalum Mesh, two spheres, even though the sphere implant is the predominantly used implant in the geographical area. The two extruding spheres were recent enucleation cases who developed postoperative infections. All other extrusions ranged from 15 months to 20 years following enucleation.

0161-6420/83/0900/1110/$1.1 0 © American Academy of Ophthalmology

NUNERY AND HETZLER • IMPROVED PROSTHETIC MOTILITY

Fig 1. Iowa implant.

~ ..

Fig 3. Pressure points between motility implant and prosthesis.

The sphere implant has waxed and waned in popularity with the development of other types of motility implants. The sphere has been criticized for poorly transmitting movement to the prosthesis, but it has survived because of its comfort and durability. Allen has considered a sphere implant, over which the recti muscles are imbricated, only slightly better in motility than releasing the muscles into the orbit at the time of enucleation.2

The sphere implant, because of its regular surface can­not transfer motility to the prosthesis directly by engaging the prosthesis. Motility is indirectly transmitted by move­ment of fomiceal tissue (Fig 4). The prosthesis is "pulled" by the fornices and surrounding socket tissue rather than pushed by contact with the implant. While this is generally

Fig 2. Movement of prosthesis by Iowa implant.

Fig 4. Movement of sphere implant poorly transmitted to prosthesis.

less effective in moving the prosthesis, it reduces the pres­sure points on conjunctival tissue between the implant and prosthesis. This contributes to less pain, discharge, and less risk of extrusion.

The objective, then, of our technique modification is to combine the motility features of the irregular motility implants with the improved comfort and safety of the sphere.

We have chosen to modify the traditional sphere im­plant technique by (1) direct attachment of muscles to

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OPHTHALMOLOGY • SEPTEMBER 1983 • VOLUME 90 • NUMBER 9

Fig S. Peritomy and isolation of recti muscles.

Fig 7. First layer of Tenon's fascia closure.

fornices rather than to the implant; (2) use of autogenous cartilage or eyebank-preserved sclera as a template for transmission of extraocular motility and as a barrier against extrusion of the implant; (3) double Tenon's fascia closure to protect against extrusion; and (4) inferior fornix deepening suture in routine enucleation to assist in pros­thetic fitting.

MATERIALS AND METHODS

A 3600 limbal peritomy and isolation of the recti mus­cles are performed in the usual fashion. Recti muscles are engaged with double-armed 6-0 Vicryl suture and disinserted (Fig 5). The superior oblique tendon and the inferior oblique muscle are also disinserted. The inferior oblique muscle may be sutured directly to the lateral

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_ Tenon's

. -- Sphere implant

--Recti mm.

Fig 6. Sphere implant inside Tenon's fascia.

between Tenon's

fascia and rectus m.

Fig 8. Double-layer "x" closure of Tenon's fascia.

rectus muscle for greater support of the implant. An enu­cleation snare is used to remove the globe.

An 18 mm or larger silicone spherical implant is placed in Tenon's fascia (Fig 6). Double-layered, x-shaped closure of Tenon's is made as close to the extraocular muscles as possible. This is done by closing superior nasal Tenon's fascia to the inferior temporal fascia. Superior temporal fascia is then closed to inferior nasal fascia anterior to the first suture line (Figs 7, 8).

An ovoid template, fashioned from autogenous auricu­lar cartilage, is then placed over the anterior surface of the socket (Fig 9). Preserved-eyebank sclera can be used as a substitute for cartilage.

Double-armed Vicryl sutures, through the extraocular muscles, are then sutured through the edges of the cartilage and then directly to the apices of the fornices. The con­junctiva is closed directly over the cartilage (Fig 10).

NUNERY AND HETZLER • IMPROVED PROSTHETIC MOTILITY

Fig 9. Auricular cartilage placed anterior to Tenon's fascia.

Conformer-----

Inferior fornix suture __ _

Fig 11. Inferior fornix retention sutures to orbital periosteum.

A silicone conformer is placed into the socket and sutured through the inferior fornix with two double-armed 4-0 sutures. The sutures are placed through the con­former, through the fornix, past the periosteum of the inferior orbital rim by a large, curved, general closure cutting needle and tied over the lower eyelid (Fig 11).

RESULTS

This technique has been used in 25 cases with follow­up of 1 month to 3 years. Examples of motility using the described technique are shown. Case no. 1 is a 24-year­old diabetic woman with primary enucleation (Figs 12, 13). Case no. 2 is a 38-year-old woman with enucleation

.. Fig 10. Closure of conjunctiva.

Fig 12. Case no. I Socket movement.

for malignant melanoma (Fig 14). Case no. 3 is a 21-year-old woman posttrauma who was referred to us with an extruding Iowa implant and painful socket. The post socket revision with the modified sphere technique is shown (Figs 15, 16).

DISCUSSION

Direct suturing of extraocular muscles to the fornices allows movement of the muscles to be transmitted directly

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OPHTHALMOLOGY • SEPTEMBER 1983 • VOLUME 90 • NUMBER 9

Fig 13. Case no. 1 Prosthesis motility.

Fig 15. Case no. 3 Extruding Iowa motility implant and painful socket.

to the fornices. 3 Since the pulling effect on the fornices is the most important determinant of movement with the sphere implant, the motility is maximized.

According to Starling's hypothesis, relating effectiveness of muscle contracture with resting length of the muscle, muscular contracture is maximized by not unnecessarily stretching the muscle beyond the original muscle length. Placement of extraocular muscles directly to fornices avoids unnecessary stretching over the implant.

The aspect of a double-layered Tenon's closure ante­riorly provides additional security against extrusion with­out placing the implant behind posterior Tenon's. The

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Fig 14. Case no. 2 Motility of prosthesis.

Fig 16. Case no. 3 After socket revision with sphere implant technique.

use of autogenous cartilage as a template anteriorly acts as an additional barrier to extrusion. Because cartilage is more rigid than conjunctiva, it helps to improve trans­mission of the fornix movement to the remainder of the socket by moving socket tissue as a unit.

The final step of deepening the fornix helps to insure the optimal anatomy for prosthetic fitting and support of the prosthesis.

NUNERY AND HETZLER • IMPROVED PROSTHETIC MOTILITY

After surgery the modified impression technique of prosthetic fitting allows the movement of the fornices to be transmitted to the prosthesis. Contouring the volume and peripheral curves of the prosthesis to fit the fornices in a glove-like fashion, without unnecessary distortion, maintains the external contour of the lid and prevents restriction of movement by pressure of tissue bands on the prosthesis. Also, impression fitting takes advantage of irregularities in the socket created by the cartilage graft and suturing of recti muscles to fornices.

Helveston,4 SolV Shannon,6 McCord,7 and others have described the use of eyebank sclera for secondary revisions of extruding implants. Most reports have described cov­ering the implant directly with eyebank sclera. SolI de­scribes using sclera between the anterior and posterior layers of Tenon's fascia with the implant posterior to posterior Tenon's fascia.

McCord has described attaching extraocular muscles to the fornices and has pointed out that avoiding un­necessary stretch on the recti muscles improves strength of contracture.

Transcutaneous fornix sutures have been used to deepen the inferior fornix in patients requiring fornix revision due to malposition or shortening of the con­junctiva.

We believe the integration of all these steps into a

primary enucleation technique provides a socket easy for the ocularist to fit, comfortable for the patient, and with minimal likelihood of extrusion. The use of autogenous cartilage improves motility, reduces risk of extrusion and is well tolerated in the socket.

We believe that with this modification motility is im­proved over conventional sphere techniques, and the risk of later surgical revisions when compared to irregularly surfaced motility implants is reduced.

REFERENCES

1. Spivey BE. The Iowa enucleation implant. Trans Am Acad Ophthalmol Otolaryngol 1970; 74:1287-95.

2. Allen L. Fitting the prosthesis: a challenge. Trans Am Acad Ophthalmol Otolaryngol 1970; 74:1318-20.

3. Coston TO. The spherical implant. Trans Am Acad Ophthalmol Oto­laryngol 1970; 74:1284-6.

4. Helveston EM. Human bank scleral patch; for repair of exposed or extruded orbital implants. Arch Ophthalmol 1969; 82:83-6.

5. Soli DB. The use of sclera in surgical management of extruding implants. Ophthalmology 1978; 85:863-8.

6. Zolli C, Shannon GM. Experience with donor sclera for extruding orbital implants. Ophthalmic Surg 1977; 8(1):63-70.

7. McCord CD Jr. The extruding implant. Trans Am Acad Ophthalmol Otolaryngol 1976; 81 :587-90.

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