Purpose: To present our approach in the treatment of exposed hydroxyapatite (HA) orbital implant.
Patients and methods: Seven patients with HA orbital implant exposure presented for treatment, all primary implants, postevisceration. All patients were operated by the same surgeon. The size of implant was based on preoperative axial length measurement (ax-2 mm, subtract 1 mm for evisceration and hyperops) except for two patients with buphthalmus where 20 mm implant was used. HA implant was wraped in sclera papillar area turned anteriorly. It was pushed as far as possible into the orbit but unfortunately without using plastic drape or malleable retractors. Extraocular muscles were sutured in their anatomic position. Exposure occurred at 5-7 years of implantation. Six patients wore glass orbital prostheses, and one silicone orbital prosthesis. The size of dehiscence of conjunctiva and Tenon's capsule varied from 5 to 15 mm. A woman with 15 mm exposure presented first with 6 mm exposure. However, she declined immediate surgery and continued to wear glass epiprosthesis. She returned a year later when she could not wear epiprosthesis anymore, and the size of the defect increased to 15 mm. Two-step procedure was performed in local anesthesia. Conjunctival edges were freshened, undermined and the anterior surface of the HA implant was shaved to the depth of at least 2 mm. Tarsoconjunctival flap was tailored from the central part of the lid. Care was taken that at least four millimeters of the marginal height of the tarsal plate were kept intact to avoid lid notching. Conjunctiva was undermined superiorly to include conjunctiva and Müllers muscle into the flap. No donor sclera was available. Raw surface of the flap faced the defect. Interrupted 6-0 Vicryl sutures were put on the flap, 360 degrees around. In two patients with exposure measuring 9 and 11 mm tarsoconjunctival pedicle flap from lax lower lid was incorporated. Upper and lower lid tarsoconjunctival flaps were sutured together. Central temporary tarsorrhaphy was performed so that postoperative local antibiotic (Tobrex) could be applied through the lateral third of the palpebral opening. At four weeks, flap was divided under local anesthesia. In two patients with lower lid flaps, horizontal shortening of the lower lid for the size of the flap was perfomed. In one patient with a 15-mm defect, third surgery was required. A crescent defect starting from superonasally to inferotemporally, horizontal diameter of 4 mm, was covered with conjunctival pedicle flap, base located inferotemporally. The harvest area was covered with oral mucosa membrane graft. Follow-up varied from 2 months to 5 years.
Results: Two patients experienced thick mucous discharge starting two weeks after the first step of the surgery. Bacteria and fungi were not isolated. After a 10-day course of systemic antibiotics the discharge subsided and the flap had taken nicely. Two patients had granuloma prior to pedicle division, which was removed and the area healed. There was no evidence of further exposure in any patient and all were able to wear orbital epiprosthesis.
Conclusion: Tarsoconjunctival pedicle flap is a safe procedure to cover the exposure of hydroxyapatite orbital implant. A limited size of the flap and the need of temporary tarsorrhaphy are the only disadvantages of the procedure.