Evaluation of absorbable PLA nasal implants in an ovine model.

Objective: To examine biocompatibility and absorption profile of a poly (L-lactide-co-D,L-lactide) 70:30 nasal implant.

Methods: In an ovine model, 66 rod-shaped absorbable implants were placed in 11 nasal dorsa. The sheep were sacrificed at 1.5 (N = 3), 6 (N = 3), 12 (N = 3), 18 (N = 1), and 24 months (N = 1). The nasal dorsum was harvested from each animal. Gross and histopathological examinations were performed.

Results: There were no postoperative complications, signs of infection, or tissue rejection throughout follow-up time points. Upon sacrifice, no abnormalities were identified during gross pathological examinations. The histology of the implant sites at all time points showed the implants were fully encapsulated through 12 months. The inflammatory reaction to the implants was minimal to mild at 1.5, 6, and 12 months. At 18 months the implant material was in the mass loss phase, being actively absorbed. During this phase, the inflammatory reaction within the fibrous connective tissue capsule reached expected moderate levels. By 24 months, the inflammatory reaction had diminished in most implantation sites and complete absorption of the rod implants was noted at some sites with nodular bundles of mature collagenized fibrous tissue replacing the implant, devoid of an inflammatory infiltrate.

Conclusion: Biocompatibility of the poly (L-lactide-co-D,L-lactide) 70:30 material was demonstrated when used as a nasal implant in the nasal dorsum ovine model. Absorption of the implant occurred approximately 18 to 24 months postoperatively, and the implant site was replaced with collagenized fibrous tissue.

Level Of Evidence: NA.