Long-term result of a biodegradable osteo-inductive copolymer for the treatment of orbital blowout fracture.

Purpose: We have recently reconstructed the orbital wall using a bioabsorbable osteo-inductive copolymer as a support material for the bone defects in patients with orbital blowout fracture. The purpose of this study was to investigate a 2-year follow-up after implantation.

Material And Methods: In order to investigate the efficacy and safety of the bioabsorbable osteo-inductive copolymer HA-P(LA/CL), hydroxyapatite-poly(l-lactide-ε-caprolactone), we measured CT density of the implanted copolymers in 7 patients at such time points as 1 week, 6 months and 2 years after surgery along with the long-term outcomes with regard to postoperative complications.

Results: Five patients in whom the intraoperative maximum width of the bone defect was less than 15 mm demonstrated the fracture types of either linear or trap-door. All patients treated with HA-P(LA/CL) copolymer indicated good bone formation with high CT density (>500) at 2 years postoperatively. In contrast, 2 patients in whom the intraoperative maximum width of the bone defect was more than 16 mm demonstrated a punched-out type fracture. Postoperative CT of the HA-P(LA/CL) copolymer showed low density (28.0 and 173.4) at 2 years postoperatively, indicative of limited bone formation. None of the cases demonstrated significant postoperative complications such as diplopia, enophthalmos, infection and extrusion of the implant material.

Conclusion: The results of this study demonstrate that surgical treatment of orbital blowout fractures using bioabsorbable osteo-inductive copolymer was useful in linear and trap-door fractures.