Abstract
Abstract: :
Purpose: To compare the rates of implant exposure and implant migration among patients who received an unwrapped non–porous versus unwrapped porous spherical orbital implant immediately following enucleation. Methods:Retrospective clinical study of 248 consecutive patients who underwent primary enucleation performed by a single surgeon (JJA) during the interval January 1988 through August 2003. Clinical records were reviewed and the following baseline variables were abstracted for each patient: patient age and gender, indication for enucleation, implant type (hydroxyapatite [HA], porous polyethylene [PP], or polymethylmethacrylate [PMMA]), implant size, ipsilateral orbital irradiation (preoperative or postoperative) and systemic chemotherapy in the perioperative period. The following outcome variables were abstracted from the post–enucleation follow–up records: conjunctival and subconjunctival connective tissue dehiscence or breakdown over the implant resulting in implant exposure, migration of the orbital implant, extrusion of the implant, infection of the implant, and secondary orbital reconstructive surgical procedure. Actuarial rates of the specified complications were computed using the Kaplan–Meier method. Results: Sixty–seven patients received a non–porous (PMMA) implant and 181 patients received a porous (HA or PP) implant. Implant migration occurred in 11 of the 67 non–porous implant cases (16.4%) but in only 1 of the 181 porous implant cases (0.55%). Cumulative actuarial probability of implant migration at 60 months was 18.5% for the non–porous versus 0.5% for the porous implants. Implant exposure occurred in 1 of the 67 non–porous implant cases (1.5%) and in 2 of the 181 porous implant cases (1.1%), both of which had received a HA implant. Exposure of the HA spheres was managed successfully with revision of conjunctival closure in one of these 2 cases and healed spontaneously in the other. One of the 2 cases of porous implant exposure occurred in an adult who underwent plaque radiotherapy prior to enucleation for uveal melanoma and the one implant exposure of a non–porous sphere occurred in a child who received external beam and plaque radiotherapy prior to enucleation for retinoblastoma. The exposed non–porous implant extruded and required substitution. No implant infection occurred in this series. Mean patient follow–up in this study was 47.5 months. Conclusions: Orbital implant migration occurred in a substantially greater proportion of patients who received a non–porous spherical implant than in those who received a porous spherical implant. The implant exposure rate was low in both subgroups.
Keywords: anatomy • orbit • wound healing