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The procedure may be performed under general or local anesthesia, according to the surgeon's preference. In either case, the injection is given in the retrobulbar space. An antibiotic (e.g., cefazolin) and an anti-inflammatory (e.g., dexamethasone) are also given intravenously.
Opening the Globe
An evisceration can be performed with or without a keratectomy, although it is preferable to preserve the cornea if possible. If the cornea must be removed, it should be completely excised following the peritomy. Cocaine is applied topically to the corneal epithelium to loosen this tissue, and the epithelium is then scraped away with a scalpel. A 360° peritomy is performed and a stab incision is made at the 12 O'clock position, 5-mm posterior to the limbus. The wound is then opened to the right and left for 180° and the intraorbital contents are delivered with an evisceration spoon. The endothelium is removed and neurosurgical peanuts are used to remove as much pigment as possible from within the scleral envelope. Any remaining pigment is removed by scrubbing with cotton-tipped applicators soaked in 95% alcohol, with care taken to avoid conjunctival inflammation from contact with the alcohol. Irrigation with suction is then performed to remove the residual pigment and alcohol.
Sizing the Scleral Envelope
The diameter of the scleral envelope is then measured using a set of graduated sizing spheres. The initial incision can be extended to allow access to the intrascleral envelope and, if needed, anterior relaxing incisions can be made between the medial and superior rectus muscles, and between the superior and lateral rectus muscles. The edges of the sclera are then tagged with 4-0 Vicryl suture and are held open using hemostats. If the scleral envelope is too small to accommodate the required implant size, then the posterior aspect is opened to allow the implant to protrude into the muscle cone. An incision is made around the optic nerve and the optic nerve is released. Relaxing incisions are then made from this hole anteriorly into the quadrants between the rectus muscles. These incisions should be no longer than is necessary to accommodate the implant without tension on the anterior closure. Periodic measurements with the sizing sphere should be made to confirm the level of relaxation.
Placing the Implant
The hydroxyapatite implant is soaked in antibiotic solution and wrapped in plastic draping material for ease of insertion. Two 5-inch squares of plastic draping material [e.g., 3M (TM) 1060 or 1020] are overlapped by 0.25 to 0.5 inches and the implant is placed on the overlap. The material is then gathered up in a purse-like fashion around the implant. The wrapped implant is then inserted into the scleral envelope, and the plastic is removed while the implant is held in place with a finger.
The scleral opening, relaxing incisions, and perilimbal incision are then closed with interrupted 5-0 Vicryl sutures, with the knots either buried or left exposed. Tenon's capsule is then closed anterior to the cornea with interrupted 5-0 Vicryl sutures and the conjunctiva is closed with a running 5-0 Vicryl suture. A medium-sized conformer is then placed and two tarsorrhaphy sutures are placed in the lid to manage the additional swelling associated with eviscerations.
Dressings and Postoperative Care
The dressings and postoperative care for an evisceration are identical those for an enucleation, except that the tarsorrhaphy is not released until 1 to 2 weeks postoperatively, when the edema has subsided. The socket can be fit with an artificial eye 6 to 8 weeks postoperatively.