COMPLICATIONS OF POROUS SPHERICAL ORBITAL IMPLANTS

Purpose: To determine the complications observed with using porous sph erical orbital implants (hydroxyapatite and porous polyethylene) and t he factors leading to their occurrence. Methods: A total of 101 cases of porous spherical orbital implantation by five ophthalmic surgeons w ere reviewed retrospectively. The demographic data, diagnosis, prior s urgery, type and technique of surgery, implant characteristics and pro sthesis fitting were described in patients with complications. Results : Eleven of the 101 patients had implant exposure. There were six male (1 with bilateral involvement) and four female patients, ranging in a ge from 2 to 71 years. Preoperative diagnosis included trauma in five patients, nontrauma in five, and tumor in one. Seven had prior eye sur geries. Three patients underwent evisceration, whereas eight underwent enucleation. Eight hydroxyapatite and three porous polyethylene impla nts were used with diameters of 16 to 20 mm. Three were unwrapped, six were wrapped in sclera, and two were wrapped in preserved fascia. Exp osures, which generally occurred within 1 year, were grouped into smal l (1-5 mm), medium (6-10 mm), and large (>10 mm). One delayed case occ urred after drilling. Small stable exposures were managed conservative ly. Larger exposures were managed either by implant revision or replac ement. All patients were fit ultimately with a prosthesis. Histopathol ogic findings of explanted spheres showed fibrovascularization limited to the periphery with moderate inflammatory reaction. Conclusion: Com plications were significantly higher in cases of eviscerations than en ucleations. Complicatations occurred in implants either unwrapped or w rapped in homologous grafts. None of the autologous wrapping had expos ure. Secondary procedures may initiate exposure when fibrovascular sta tus of implant is inadequate.