Intertransverse process fusion with the aid of chemosterilized autolyzed antigen-extracted allogeneic (AAA) bone.

Forty intertransverse process spinal fusions were performed across two to three vertebrae in four cases of fracture-dislocations of the dorsolumbar region and 36 cases of degenerative joint and disk disease, including spinal stenosis and spondylolisthesis of lumbosacral segments. In all cases, arthrodesis was performed with a composite of AAA cortical bone strips and local autologous spongiosa, including lamellar bone chips. The iliac crest was not used as a donor site in any case. The apophyseal joints were erased, packed with autologous bone slivers, and transfixed with AAA bone pegs. In selected cases, AAA cortical bone "H-blocks" were also placed between the spinous process as in a routine posterior lateral arthrodesis. In cases of bilateral total laminectomy for fractures or spinal stenosis, the excised cancellous bone chips were cleaned of soft parts and transplanted across the transverse processes beneath and around the AAA cortical bone implants. In the above-described operations, graded by the Anatomic-Functional Economic (AEF) system, the long-term excellent and good results were: 4/4 in fracture dislocations; 23/28 in degenerative arthritis and spinal stenosis; 5/8 in spondylolisthesis. Overall, there were over 80% excellent and good results; the pseudarthrosis rate was 12%. In a comparable surgical procedure with autologous iliac bone in 58 control cases, reported in the foregoing article in this volume, the minimum pseudarthrosis rate was 8%. Raw band bone, either frozen or freeze-dried, is now either so infrequently considered or unavailable for lumbar spinal operations or unavailable for lumbar spinal operations that further investigations of AAA bone grafts are warranted in a statistically significant number of patients. Although autologous bone is the ideal bone for a graft, the most important incentive for further investigations of AAA bone is the avoidance of complications of excision of massive bone grafts from iliac crests.