Anterior Reconstruction With Nano-hydroxyapatite/polyamide-66 Cage After Thoracic and Lumbar Corpectomy

Abstract

Cages are used to regain stability of the anterior spinal column following vertebrectomy, which could prevent significant donor-site morbidity from the iliac autograft harvesting and the risk of disease transmission associated with the allograft. The hollow, porous, cylindrical nanohydroxyapatite/polyamide 66 (n-HA/PA66) cage is a new nonmetallic cage device made by combining nanohydroxyapatite with polyamide 66. Few studies have examined its effectiveness and outcomes over a follow-up >2 years.We retrospectively studied 51 consecutive patients with acute traumatic thoracic or lumbar burst fracture who underwent anterior reconstruction with the n-HA/PA66 cage following single-level corpectomy. Radiologic parameters (radiographs and 3-dimensional computed tomography scans) preoperatively and at 1 week and >2 years postoperatively, as well as clinical outcome parameters (SF-36 scores), were analyzed. Mean kyphosis correction in the segment within the cage was 11.8°±7.1°, and mean loss of correction at last follow-up was 1.9°±2.1°. Osseous fusion was achieved in 90.2% of patients, and severe cage subsidence (settling >2 mm) was observed in 19.6% of patients at final follow-up. Significant differences were found in 7 of 8 health dimensions of the SF-36 between neurologically intact patients and neurologically injured patients. Our clinical results indicate that the n-HA/PA66 cage is an effective device for reconstruction after anterior thoracic and lumbar vertebral resection, resulting in a high rate of successful osseous fusion and a low proportion of severe cage subsidence.