The third indication for enucleation in a blind eye is atrophy bulbi. The presence of phthisis bulbi, solely a histological term, must be inferred from the clinical findings of a hypotonic, atrophic, and opaque globe ¹. Phthisical eyes have an increased incidence of choroidal malignant melanoma, which has been estimated at 4–15%^1,². Melanomas have been found in 21% of enucleated eyes that had opaque media¹, and 12% of these melanomas had been unsuspected prior to enucleation³. Because phthisical eyes with opaque media are difficult to examine clinically, enucleation may be a precautionary measure for the development of malignant disease. If not enucleated, an atrophic eye should be examined periodically with ultrasonography, MRI or CT scanning.

A fourth indication for enucleation in a blind or seeing eye is the presence of suspected intraocular malignancy. When enucleation is undertaken for malignant disease, careful attention should be paid to technique. Traumatic enucleation for malignant disease may actually hasten metastatic spread ^4,⁵.

A fifth indication for enucleation is aplasia or severe hypoplasia of a globe in childhood. Full orbital volume is essential for the development of the bony structure of the orbit ⁶. This bony asymmetry can be minimized by early placement of a large orbital implant.

A sixth indication for enucleation is as a prophylactic measure against the development of sympathetic ophthalmia. Sympathetic ophthalmia occurs most commonly after penetrating ocular trauma. Ninety percent of cases occur between 2 weeks and 1 year after penetrating ocular injury ⁷. The published incidence of sympathetic ophthalmia after penetrating ocular injury varies. It has been estimated to be as high as 3–5% of cases in one series¹. These previous studies have been exclusively retrospective and may not reflect the benefits of modern microsurgical techniques and immunosuppression.

Enucleation of an injured eye with poor visual prognosis within the first 7–10 days post-injury may prevent sympathetic ophthalmia. Evisceration does not protect against sympathetic ophthalmia and may actually encourage its development.

Evisceration is performed for some of the same reasons as enucleation. The first indication for evisceration is a blind eye with active, uncontrolled endophthalmitis. Evisceration may be less likely to spread infection to cerebral spinal fluid than would enucleation, in which severing of the optic nerve sheath is required ⁸. If infection has already spread through the sclera, however, enucleation may be necessary to remove all the infected tissue. Often a secondary enucleation is performed after the infection has cleared.

The second relative indication for evisceration occurs in a severely ill patient who cannot tolerate general anesthesia. Evisceration of a blind eye is technically easier and quicker to perform under local anesthesia.

A third indication for evisceration is a blind eye in a patient with a severe bleeding disorder or in anticoagulated patients. Less orbital dissection in evisceration reduces the risk of orbital hemorrhage.

Evisceration is contraindicated in the presence of intraocular malignancy because it may contribute to dissemination. Similarly, evisceration should not be used in atrophi bulbi and hypoplasia in childhood because an adequate sized implant cannot be placed inside the scleral shell and an eye with atrophy bulbi may harbor an unsuspected malignancy. Evisceration should not be performed for prophylaxis against sympathetic ophthalmia since choroidal tissue may not be completely removed.

Enucleation techniques

Most present day enucleation techniques are derived from similar principles and vary only in the subtleties of implant choice and technique of reattaching disinserted extraocular muscles.

Enucleation can be performed under either general or local anesthesia, although general anesthesia is preferable. Under local anesthesia, stimulation of the optic nerve at the time of transection may lead to sudden, intense visual perception known as the Augenblick phenomenon, which may be distressing to the patient. Also, retrobulbar anesthesia may not lead to complete loss of sensation in the extraocular muscle tissue, which may result in a procedure that is uncomfortable for the patient and technically difficult for the surgeon.

Authors’ technique

After administration of general anesthesia, 10 cc of 1% lidocaine with 1 : 100 000 dilution epinephrine in a 50 : 50 mixture with 0.5% plain bupivacaine are injected subconjunctivally around the limbus and into the retrobulbar space. This assists in the separation of the conjunctiva from the sclera, aids in the hemostasis of the orbit, and provides temporary postoperative pain control.

Retraction sutures are then placed through the center of the lid margin in the upper and lower eyelids. An eyelid speculum may be used as a substitute. A 360° limbal peritomy is performed, simultaneously dissecting Tenon’s fascia down to bare sclera and taking care to preserve all conjunctival tissue.

A curved hemostat is used to bluntly dissect the posterior Tenon’s fascia off the globe in all four quadrants between the four recti muscles. The tips of the hemostat should be kept on the surface of the sclera while they are spread.

A muscle hook is inserted behind the medial rectus muscle to engage it. Keeping the tip of the muscle hook against the sclera while passing it behind the muscle insertion. A second muscle hook, passed from the opposite edge of the muscle, will help ensure that the entire muscle is isolated. A small amount of Tenon’s fascia may be carefully dissected from the muscle insertion site for better visualization. The integrity of Tenon’s fascia should otherwise be maintained to facilitate placement and security of the orbital implant.

A doubled-armed 5-0 Vicryl suture is passed through the substance of the muscle near its insertion site with locking bites at each edge of the muscle for additional security. The muscle tendon is then transected from the globe (Fig. 55.1). A small stump of tendon may be left on the sclera to assist in globe manipulation. In a similar manner, the remaining three recti muscles are isolated, ligated, and disinserted from the globe. All needles are left on the sutures for later use.

Fig. 55.1 Hooked muscle with sutures attached, being cut with Wescott scissors.

The superior oblique muscle tendon is then engaged with the muscle hook by passing it from the superonasal quadrant out laterally. The tendon is then transected. The superior oblique muscle may be secured to the superior rectus muscle by passing the sutures already attached to the superior rectus through the superior surface of the superior oblique tendon and securing it with several knots. Once again, the sutures are left intact.

After disinsertion of all extraocular muscle attachments, a careful inspection of the globe is made to verify that all Tenon’s fascia attachments have been bluntly dissected away from the globe. The vortex veins can be identified and cauterized to reduce bleeding. Blunt dissection and inspection are carried back to the optic nerve sheath.

The nerve is transected with either an enucleation snare or a pair of enucleation scissors (Fig. 55.2A&B). If scissors are used, it may be helpful to crush the optic nerve with a hemostat prior to transection. In this technique, a curved hemostat is inserted behind the globe from a medial approach, with the concave angle facing anteriorly and the tip toward the optic nerve. The hemostat is used to feel the optic nerve with the tips closed. Once the nerve is located, the tips of the hemostat are slipped around the nerve and then slid posteriorly along the nerve toward the apex of the orbit. The nerve is then clamped for hemostasis. A curved enucleation scissors is placed just above the hemostat using the same maneuver. Next, the nerve is transected just anterior to the hemostat. Bipolar cautery may be used to coagulate the transected nerve end to seal off the central retinal artery.

Fig. 55.2 (A) Enucleation snare in place. (B) Clamp and enucleation scissors in place.

If an enucleation snare is used, clamping of the nerve is not necessary. The snare loop is placed around the globe from either a lateral or a medial approach, being sure the extraocular muscles and other orbital tissue are not engaged. The wire loop is then tightened so it is just slightly larger than the diameter of the nerve. The snare is then slid posteriorly along the nerve to the apex before it is used to sever the nerve. This maneuver minimizes the risk of transecting other orbital contents. The severed nerve end may be located and cauterized if desired. There should be at least a 5 mm segment of optic nerve attached to the globe. In cases of intraocular malignancy, a segment of 10 mm is desired.

Bleeding is usually minimal, especially when the snare is used. When bleeding does occur, one can pack the orbit with thrombin-soaked Gelfoam and apply direct pressure. Random and excessive cautery must be avoided as damage to apical structures or chiasmal injury from transmission along the optic nerve toward the chiasm may result. Likewise, excessive traction on the optic nerve should be avoided.

The ‘no touch’ technique

The ‘no touch’ technique was advocated by Fraunfelder and Wilson ⁴ for enucleation of eyes that harbor intraocular malignancy. Zimmerman, McLean and Foster⁵ have suggested that enucleation may precipitate metastatic spread of melanoma through the dissemination of tumor emboli.

In the ‘no touch’ technique no direct pressure is placed on the eye during enucleation. All tissue is lifted away from the eye prior to cutting. The extraocular muscles are cut without using muscle hooks. After extraocular muscle release, a cryoprobe is applied to the sclera over the tumor.

No studies to date have conclusively shown the efficacy of the ‘no touch’ technique in reducing the mortality associated with enucleation for intraocular melanoma. Prudence would dictate the most delicate enucleation possible when dealing with an intraocular malignancy. In tumor-harboring eyes, we modify our technique by keeping the traction on the eye to a minimum when hooking the extraocular muscles. Minimal traction on the globe is used when severing the optic nerve. Attention to leaving a very long segment of optic nerve attached to the globe is paramount. Location of the extraocular muscles is achieved through direct visualization and sutures are not passed through the muscles until after the globe is removed from the orbit.

Placement of orbital implant

Placement of an orbital prosthesis is almost universally performed in conjunction with an enucleation. We will describe our technique for placement of our preferred implant, the silicone sphere. Dermal-fat grafting will also be described as an invaluable technique for replenishing orbital volume in secondary reconstruction sockets.

Orbital implants

The silicone sphere, hydroxyapatite, and porous polyethylene implants are the most common synthetic implants in current use. Due to its low rate of complications and extrusions, our preference is the silicone implant. Alternatively, the hydroxyapatite implant may be used in selected cases where there is no microvascular disease, radiation exposure, or multiple surgeries, resulting in an increased extrusion or exposure rate ^12,¹³. Silicone is also considerably less expensive than hydroxyapatite or porous polyethylene. Multiple studies demonstrate no difference in motility between non-porous and porous implants¹⁴.

Silicone sphere

After enucleation, a silicone sphere of appropriate size is selected. A 20 mm spherical implant coupled with an average-sized ocular prosthesis will adequately fill orbital volume in an enucleated socket ⁹. If the implant is less than 20 mm, orbital volume loss with secondary superior sulcus deformity may result.

In children, the largest implant the orbit can accommodate should be placed. This will be between 14 and 19 mm, depending on the age of the child and the size of the orbit. When smaller implants are employed, secondary revisions of the implant may be necessary to stimulate optimal growth of the orbit during childhood.

Authors’ technique

The implant is wrapped in autogenous sclera after thorough removal of uveal tissue. Banked sclera or autogenous fascia lata may be used as a substitute. A 5-0 Vicryl suture may be used to approximate the edges of the wrap (Fig. 55.3). If sclera is used, the implant will be exposed at the corneal opening, which will be placed facing the apex of the orbit. The uvea must be meticulously scrubbed off the sclera, which is then rinsed thoroughly with normal saline or antibiotic solution. Autogenous sclera is not used in a case involving suspected malignancy.

Fig. 55.3 Wrapping of implant sphere.

The wrapped implant is then placed deep within the muscle cone. The extraocular muscles are sewn to the wrapping material or directly to the implant in their approximate normal anatomical positions using the previously placed sutures. The needles are left on the sutures after the muscles are attached to the implant (Fig. 55.4). The muscles should not be imbricated over the anterior surface of the implant. This will not provide a barrier for extrusion, as the implant may easily extrude through the area between the recti muscles. Furthermore, the imbricating technique encourages migration of the implant, usually in the superior temporal direction^10,¹¹.

Fig. 55.4 Muscles sewn onto implant.

Tenon’s fascia and the conjunctiva are then draped over the implant. All four double-armed sutures still attached to the muscles and implant are then passed full thickness through the overlying fascia and conjunctiva from the deep to anterior surface, without shortening the fornices or retracting the tissue edges. The sutures are then tied and trimmed. This maneuver pulls the tissue layers posteriorly onto the implant. Tenon’s fascia is then closed with interrupted 5-0 Vicryl sutures with buried knots. The conjunctiva should be easily closed with a running 5-0 Vicryl suture without any tension on the wound.

After wound closure, antibiotic ointment is placed into the fornices and a plastic conformer is placed behind the lids. The conformer should be as large as possible but not so large that it places tension on the wound when the lids are closed. A temporary tarsorrhaphy may be performed. No dressing is required, although a light dressing may be applied.

Dermis-fat grafting

The dermis-fat grafting technique employs an elliptical graft of dermis and subdermal fat taken from the buttocks or abdominal area. The epidermis is denuded prior to fat excision.

Posterior Tenon’s fascia is opened in all four quadrants allowing orbital fat to come into contact with the grafted fat tissue. The dermal-fat graft is placed directly into the anophthalmic socket with the fat facing posteriorly. The recti muscles are sutured to the margins of the dermis. Tenon’s fascia and the conjunctiva are then sutured directly overlapping the margin of the dermal fat graft (Fig. 55.5). The desired orbital volume is over-corrected by approximately 20% to allow for reabsorption of the fatty graft.

Fig. 55.5 Suturing in of dermal fat graft (muscles, Tenon’s, conjunctiva).

Autogenous composite dermal fat grafting provides the advantage of no likelihood of implant extrusion or migration. Dermal-fat grafted sockets frequently have good motility and are usually comfortable after prosthetic fitting ^15,¹⁶. Unfortunately, the rate of reabsorption of transplanted fatty tissue is unpredictable. Fat reabsorption may lead to superior sulcus deformity and clinically significant eyelid retraction, which occurs when recti muscles and lid retractor muscles become adherent to the fat graft (Fig. 55.6).

Fig. 55.6 Fat-induced eyelid retraction.

In the authors’ experience, reoperations within the first 3 years of dermal fat grafting occur in approximately 60% of cases ¹⁷. Two of every three patients require major refabrication of the ocular prosthesis within 1 year of surgery, to compensate for changes in socket anatomy from fat reabsorption.

We have found the dermal-fat graft implant to be helpful in patients who have significant orbital tissue loss, patients with cicatricial shortening of the fornices, and patients who have had implant extrusions. We have found this technique less suitable for routine post-enucleation implants because of the high incidence of surgical and prosthetic revisions.

Orbital implantation in pediatric patients

A normally growing eye stimulates expansion and development of the orbit until bony growth is complete. Pediatric orbits without normal-sized eyes become hypoplastic and may cause ipsilateral facial hypoplasia ^6,^18,¹⁹. Effect of orbital volume deficit on bony growth in childhood is greater in cases of congenital anophthalmia or severe microphthalmia when compared with acquired anophthalmia in later childhood. Children with normal sized globes during embryonic development and early childhood are more likely to retain a relatively normal cosmetic appearance than to those with congenital anophthalmia. Hintschich et al. demonstrated loss of orbital bony volume in both pediatric and adult patients undergoing enucleation²⁰. The loss of orbital bony volume increased with the passage of time from enucleation, with the greatest volume loss occurring in children enucleated in the first 2 years of life.

Treatment of the pediatric anophthalmic socket should begin as early as possible. Cepela, Nunery and Martin demonstrated that bony stimulation was proportional to the volume of the implant placed into the orbit. Therefore, the largest implant possible (up to 20 mm in diameter) should be placed. Heinz, Nunery, and Cepela also showed that the amount of achievable orbital expansion was inversely proportional to the age at which expansion begins. Treatment may include placing sequential orbital expanders ²¹. We prefer to initially place the implant into the orbit via a lateral orbital approach without disturbing the conjunctiva. An expandable orbital implant that enlarges with saline injections is an alternative to sequential replacement of orbital sphere implants.

Evisceration technique

Historically, evisceration has been considered to be a technique that provides better motility of the prosthesis and a better cosmetic result than does enucleation ²². This may be true if enucleation techniques such as release of the recti muscles or imbrication over the anterior surface of the implant are employed.

With current techniques, the final cosmetic appearance of the enucleated socket is as good as or better than the eviscerated socket. The enucleated socket is more likely to achieve full volume. Prosthesis motility following enucleation in our experience compares favorably with prosthesis motility in the eviscerated socket. A cosmetic advantage should therefore not be considered an indication for evisceration.

Evisceration may also have a higher incidence of implant extrusion. One series demonstrated the incidence of extrusion as being four times (6% vs. 1.4%) greater with evisceration than with enucleation ²³.

In the authors’ experience, enucleation provides the more satisfactory long-term result. When careful enucleation technique is employed, the result is a stable socket with good volume, good motility, and only a small chance of further surgical revision.

Authors’ evisceration technique

Under general or monitored anesthesia, a 360° limbal peritomy is performed. A No. 11 or No. 15 Bard–Parker blade is used to enter the eye at the limbus and a full-thickness incision around the entire limbus is completed (Fig. 55.7). The intraocular contents are removed with an evisceration spoon or periosteal elevator (Fig. 55.8). The intraocular surface of the sclera is vigorously scrubbed free of uveal tissue. The gauze may be soaked with 100% ethanol or 10% phenol to denature any remaining uveal protein. Care must be taken to avoid spilling either on the conjunctival surface. The sclera should then be irrigated with a copious amount of normal saline solution.

Fig. 55.7 Removal of cornea from sclera.

Fig. 55.8 Removal of intraocular contents.

If evisceration is performed for intraocular infection, the sclera should be irrigated with antibiotic solution and packed with antibiotic gauze until the infection subsides. The packing is usually removed after 24–48 hours. Once the infection is cleared, the remaining sclera may be excised in preparation for placement of an orbital implant. Alternatively, an orbital implant may be placed into the eviscerated scleral shell. Placement may be facilitated by incising the limbal scleral edge in an anterior–posterior direction to create a larger anterior opening (Fig. 55.9). Additionally, posterior radial incisions may be made in the sclera to allow placement of a larger implant. Anterior sclera, Tenon’s fascia, and conjunctiva are closed separately with 5-0 Vicryl sutures. We avoid using hydroxyapatite implants in evisceration patients because we believe a higher exposure rate occurs, compared with non-porous implants. Once the implantation is completed, a conformer is placed behind the lids and a temporary 6-0 mild chromic suture tarsorrhaphy is placed.

Fig. 55.9 Limbal scleral relaxing incisions.

Complications of enucleation and evisceration

Early enucleation complications

Superior–temporal implant migration may cause ptosis by impeding the superior rectus and levator (Fig. 55.10). The prosthesis may therefore be custom-designed with minimal superior volume to eliminate further restriction on the levator. Ptosis buckles on the prosthesis are ineffective when ptosis is caused by a migrated implant.