Use of the anterior interbody fresh-frozen femoral head allograft in circumferential lumbar fusions.

Many studies in the literature have documented the outcome of circumferential lumbar fusions. However, no study has specifically evaluated the performance of the anterior fresh-frozen femoral head allograft as a structural interbody graft material. All office and hospital records, including charts and radiographs, were reviewed to obtain pertinent clinical and radiographic information. The cases included 23 single-level fusions, 22 two-level fusions, and 5 fusions of three or more levels. In all, 88 fusion levels were analyzed radiographically. The mean follow-up time was 28 months (range, 24 to 36 months). All procedures were performed in a single stage. At the latest follow-up, clinical outcome was graded good to excellent in 39 (78%) cases, fair in 8 (16%) cases, and poor in 3 (6%) cases. The average time to anterior radiographic fusion was 6 months (range, 4 to 8 months). The overall fusion rate was 98%. The average preoperative anterior disk space height was 10 mm, 14 mm immediately after operation, and 13 mm at follow-up. The posterior disk space height averaged 5 mm before operation, 7 mm immediately after operation, and 6 mm at follow-up. The average segmental lordosis was 7 degrees before operation, 10 degrees immediately after operation, and 10 degrees at follow-up. Late postoperative disk space collapse of 3 mm or more was noted in 17% of the fused disk spaces examined. Seventy-eight percent of the disk spaces maintained a disk space height greater than that of their preoperative value at the latest follow-up. Segmental lordosis did not change significantly at follow-up. The occurrence of collapse did not correlate with the clinical result, smoking history, or surgical indication (p < 0.05). Perioperative complications included one pleural effusion, two urinary tract infections, and one deep wound infection. Late complications included five painful graft sites and two patients with pseudarthrosis. Fresh-frozen femoral head allograft fulfills its desired function as an anterior structural graft in combination with rigid posterior transpedicular fixation, maintaining the disk space height achieved at surgery while reliably allowing remodeling and incorporation into a solid anterior fusion.