713717 - Viable Cellular Allograft for Spine Fusion: Clinical Success Comparing Two Surgical Techniques

Background: Due to limited availability of autologous bone as well donor site morbidity after grafting, alternative grafts have been developed to supplement tissue without adversely affecting therapeutic value. Level I randomized trials comparing efficacy of a DBM preparation (Grafton DBM) compared with iliac crest autograft demonstrated 86% for the DBM group and 92% for the autograft group. Less positive results have been reported in contralateral comparison of DBM gel coupled with autograft vs. autograft composite in patients undergoing instrumented posterolateral fusion. After two years follow-up, fusion rates of 52% on the DBM side and 54% on the autograft offer room for improvement.

Purpose: Evaluate clinical outcomes in evolving graft materials that offer less morbidity and comparable if not superior efficacy. This data represents use of a cellular bone matrix (VIA Graft) for spine fusion in two surgical practices using different grafting techniques with the same graft.

Study Design/Setting: These data evaluate Retrospective case series from 2 surgeons utilizing different surgical techniques.

Length of follow-up: Patients in this retrospective study were followed for 24 months.

Outcome Measures: Radiographs and CT were used to evaluate fusion. Patient follow-up included clinical evaluations for pain by VAS that was not recorded for all patients in the two practices.

Methods: Surgeon #1 blended four components; VIA Graft, local autograft, BMAC, and collagen hydroxyapatite sponge, and placed in the posterolateral gutters for patients receiving posterolateral instrumented fusions, and in the posterolateral gutters, interbody spacers, and intradiscal spaces, for patients receiving posterolateral fusions and transforaminal interbody fusions.
Surgeon #2 obtained iliac crest bone marrow and mixed Via Form moldable material in a ratio of approximately 5 mL of via graft to 1 mL of bone marrow aspirate; packing approximately 2-3ml of the Via Form/bone marrow mixture into each disk space. Additional Via Form is packed into the interbody space, adequate to fill the available bone graft void/window.

Results: Surgeon #1 treated 51 patients and 79 levels, while Surgeon #2 treated 133 patients and 202 levels. Patient demographics were similar in age, diabetes, and tobacco use. Fusion were 96% and 98%, respectively, irrespective of surgical technique. Preoperative VAS for the patients in Surgeon #2’s practice was 61.9 (13-100), while VAS 12 months following was 24.8 (0-71). Two of the patients in Surgeon #2’s practice required fusion extensions because of falls, but the initial sites remained fixed and solid.

Conclusion: Evidence of successful fusion has been demonstrated using living cell/matrix combinations that rivals that of growth factor administration and exceeds that of commonly used graft extenders. Reduction in grafting and morbidity benefits patients and facilities as well in a time of resource scrutiny. Based on clinical improvements to the surgical outcomes, the surgical procedures described here were deemed safe, effective, and therapeutically successful. In patients requiring vertebral body fusion, the techniques described were effective in cohorts of 51 and 133 patients.