Exposure rate of smooth surface tunnel porous polyethylene implants after enucleation

Purpose: To determine the exposure rate after enucleation using the smooth surface tunnel (SST) and SST-EZ porous polyethylene (PP) orbital implants (Stryker Kalamazoo, MI, U.S.A.). Methods: The authors performed an institutional review board-approved retrospective review of 150 consecutively placed SST and SST-EZ PP implants after enucleation. Patient records were reviewed for comorbidities, surgical details, followup length, and presence of implant exposure. All prior published studies on porous orbital implant insertion were reviewed, and the exposure rate for patients undergoing enucleation with primary implant insertion was studied for comparison. Results: Of the 150 implants, 30 were excluded due to follow up of less than 8 weeks. Of the remaining 120 implants, 4 (3.3%) became exposed during the follow-up period (mean, 2.1 years), 2 of which were in children who underwent chemotherapy for retinoblastoma. The authors calculated a 7.1% exposure rate for all porous implant materials placed primarily after enucleation from 58 previously published studies. Conclusions: The SST and SST-EZ PP implants are well tolerated when placed at the time of enucleation. The theoretical advantage of a smooth anterior surface may indeed lead to a lower rate of exposure compared with standard unwrapped porous materials as demonstrated by the relatively low exposure rate using this implant.