Enucleation and evisceration

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CHAPTER 55 Enucleation and evisceration

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Enucleation is the removal of the globe from the orbit. Evisceration is the removal of the intraocular contents, including the uvea but leaving the sclera, and the extraocular muscles intact.

We present the indications for enucleation and evisceration, our surgical techniques for both procedures along with their complications.

Indications for enucleation and evisceration

The first indication is a blind painful eye. Long-term use of pain medication is unjustifiable due to addictive potential. Retrobulbar alcohol blocks may provide temporary relief, but also induce an acute inflammatory response and potentially a permanent orbital apex syndrome. Enucleation is permanent, effective, and safer than most alternatives when chronic pain occurs in a blind eye.

Rarely should an eye with non-malignant disease be removed while light perception exists. Exceptional indications for enucleation in an eye with vision include the presence of intraocular malignancy and following severe penetrating globe trauma with a poor visual prognosis in attempting to prevent sympathetic ophthalmia. Patients with severe pain in an eye with minimal vision must evaluate the merits of enucleation for pain relief versus the risk of some future injury to the better eye.

In view of the importance of the eyes to the patient’s overall appearance and self-image, a cosmetically disfiguring blind eye is the second indication for enucleation.

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 globe1. 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 spread4,5.

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 orbit6. 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 injury7. 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 required8. 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.

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.

In a similar manner, the inferior oblique muscle is isolated by passing a muscle hook from the inferonasal quadrant, sweeping it posterolaterally toward the area of the macula. The inferior oblique tendon is transected and secured to the lateral rectus muscle. This maneuver provides an inferior hammock that may help support the weight of the orbital implant.

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.

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