Poly(L-lactide) implants in repair of defects of the orbital floor: an animal study

Because of the life-long presence of alloplastic, nonresorbable orbital floor implants and the complications of their use mentioned in literature, the use of a resorbable material appears to be preferable in the repair of orbital floor defects. A high-molecular-weight, as-polymerized poly(L-lactide) (PLLA) was used for repair of orbital floor defects of the blowout type in goats. An artificial defect was created in the bony floor of both orbits. Reconstruction of the orbital floor was then carried out using a concave PLLA implant of 0.4-mm thickness. At 3, 6, 12, 19, 26, 52, and 78 weeks postoperatively, one goat was killed. Microscopic examination showed full encapsulation of the implant by connective tissue after 3 weeks. After 6 weeks, resorption and remodeling of the bone at the points of support of the implant could be detected. A differentiation between the sinus and orbital sides of the connective tissue capsule was observed. The orbital side showed a significantly more dense capsule than the antral side, which had a loose appearance. At 19 weeks, a bony plate was progressively being formed, and at 78 weeks, new bone had fully covered the plate on the antral and orbital side. No inflammation or rejection of the PLLA implant was seen.