Magnetically integrated microporous implant: safety and efficacy of secondary posting

To evaluate the surgical technique and morbidity related to secondary posting of a previously implanted 12-mm microporous high-density polyethylene implant (MEDPOR) and the enhanced motility associated with magnetic coupling of the prosthesis and the implant in a rabbit model.

Eight New Zealand rabbits underwent primary evisceration surgery with implantation of a 12-mm microporous high-density polyethylene implant. At 6 weeks, a 4 x 6-mm stainless steel, titanium-coated post was secondarily inserted in 6 rabbit eyes using a bilevel incision. Four weeks after the second surgery, 3 rabbits were fitted with a magnet-embedded prosthesis. Motility was measured by evaluating lateral prosthetic excursion during direct observation. At 3, 6, and 12 months the implants and surrounding tissues were harvested for histopathologic examination.

Secondary placement of the post within the implant was accomplished without difficulty. No signs of erosion, dehiscence, or extrusion were found after a12-month follow-up in any of the study eyes. Clinical grading documented increased movement of the magnetically coupled prostheses compared with nonmagnetically integrated control eyes.

This study establishes the safety of secondary posting and the efficacy of magnetically integrated microporous high-density polyethylene implants in the rabbit model.

This technique may offer an alternative to patients with previously implanted microporous high-density polyethylene implants seeking enhanced cosmesis and prosthetic motility.