Exposure and Extrusion of the Implant
Implants may extrude if placed too far forward, if closure of anterior Tenon capsule is not meticulous, or if the irregular surface of the implant mechanically erodes through the conjunctiva (Fig 8-7). Postoperative infection, poor wound healing, poorly fitting prostheses or conformers, pressure points between the implant and prosthesis, and compromised vascularity may also contribute to exposure of the implant. The formation of a pyogenic granuloma is suggestive of an implant exposure (Fig 8-8).
Exposed implants are subject to infection. Although small defects over porous implants may, in rare instances, close spontaneously, most exposures should be covered with scleral patch grafts or autogenous tissue grafts with a sufficient vascular bed to promote conjunctival healing. When implants are deeply seeded with infection, removal of the implant is usually required, followed by an autogenous dermis-fat graft (Fig 8-9).
Figure 8-7 Exposure of a porous polyethylene implant in the left socket.
(Courtesy of Audrey C. Ko, MD.)
Figure 8-8 Pyogenic granuloma of the right socket following enucleation.
(Courtesy of Bobby S. Korn, MD, PhD.)
Figure 8-9 Dermis-fat graft placement in the left anophthalmic socket.
(Courtesy of Cat N. Burkat, MD.)
Dermis-fat grafts may be used when a limited amount of conjunctiva remains in the socket. This graft increases the net amount of conjunctiva available as the conjunctiva reepithelializes over the front surface of the dermis. Dermis-fat grafts should also be used in patients with a vascularized bed of tissue or vascularized implant. Unpredictable fat resorption is a drawback to the dermis-fat graft technique in adults. However, as stated earlier, dermis-fat grafts in children appear to grow along with the surrounding orbit and may help stimulate orbital development if enucleation is required during infancy or childhood.
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.