Enucleation with unwrapped porous and nonporous orbital implants: a 15-year experience

Abstract

Purpose: To compare the rates of implant exposure and implant migration among patients who received an unwrapped nonporous spherical implant versus an unwrapped porous spherical implant immediately after enucleation.

Methods: Retrospective analysis of a series of 258 patients who received either an unwrapped nonporous spherical implant (n = 68) or an unwrapped porous spherical implant (n = 190). Actuarial rates of migration of the implant and conjunctival dehiscence leading to implant exposure were computed.

Results: Sixty-eight patients received an unwrapped nonporous implant (polymethylacrylate [PMMA]) and 190 patients received an unwrapped porous implant (139 hydroxyapatite [HA] and 51 porous polyethylene [Medpor]). Median follow-up duration in this study was 37.6 months. Implant exposure occurred in 1 of the 68 nonporous implant cases (1.5%) and in 4 of the 190 porous implant cases (2.1%). This difference is not statistically significant (P = 0.85). In contrast, clinically significant implant migration occurred substantially more frequently in the patients who received a nonporous implant. The cumulative actuarial probability of implant migration at 60 months was 15.5% for the nonporous implants versus 0.7% for the porous implants. This difference was statistically significant (P = 0.0003).

Conclusions: Orbital implant migration occurred in a significantly greater proportion of patients who received a nonporous implant than in those who received a porous implant. Implant exposure occurred at a low rate that was not significantly different in the two subgroups.