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

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.