High-density Porous Polyethylene (Medpor) as a Successful Anophthalmic Socket Implant

Abstract

High-density porous polyethylene (Medpor) has been used successfully as an implant in orbital fracture repair and in the management of both cosmetic and post-traumatic facial deformities. The material is well tolerated, resists infection, is nonantigenic, and promotes tissue ingrowth. Additionally, sutures can be passed through it. These characteristics led to its use as an implant in anophthalmic socket surgery. Twenty-one patients with anophthalmia underwent implantation of spherically shaped high-density porous polyethylene implants. The implant was used in six primary enucleations with direct extraocular muscle attachment, ten secondary implant insertions, one repeat secondary implant insertion, and five eviscerations. Postoperative follow-up averaged 19 months. During this period, there were no extrusions, infections, significant inflammatory responses, or implant exposures. One implant was removed 4 months after insertion due to inadequate initial placement secondary to a severe post-traumatic orbital deformity. Successful re-implantation was performed without complication. Postoperatively, all sockets showed good to excellent motility. Results of histologic examination of the removed implant demonstrated minimal inflammatory response and extensive fibrovascular ingrowth involving 60% of the implant substance. This initial report indicates that high-density porous polyethylene can be used successfully as an implant in anophthalmic socket surgery. Its advantages over other similar implants include a significantly lower material cost and the ability to suture the extraocular muscles directly to it without the need for a covering material such as fascia or sclera. Experimental studies are in progress to determine if this implant can be integrated with an ocular prosthesis to promote improved motility and cosmesis.