Polymethylmethacrylate orbital implants with interconnecting channels. A retrospective study following enucleation in dogs and cats

Purpose: This study describes the use of polymethylmethacrylate implants with interconnecting channels (PIIC) to fill the orbit following enucleation in 31 dogs and 11 cats. Method: Seven channels were drilled into the implant. A central channel, running from the PIIC pole to its flat surface, was used to pass sutures anchoring the PIIC to the orbital fascia, minimizing the likelihood of extrusion. Six more channels allowed ingrowth of fibrovascular tissue into the PIIC, which reduces the risk of extrusion. Patients were evaluated 3, 10, and 30 days postoperatively, with 15 of 42 patients followed for 6-20 months. Ultrasound examination was performed in seven patients 15-510 days postoperatively, and two implants were studied histopathologically. Results: Implants were well tolerated and prevented skin concavity, leading to good cosmetic results. Blood flow was imaged in vessels growing into the channels, and histopathologically a collagenous, fibrovascular capsule was seen surrounding the PIIC and invading its channels. Conclusions: PIICs are a safe and cosmetic solution to anophthalmic orbits, allowing ingrowth of blood vessels and fibrovascular tissue.