Rate of Fusion Using Novel Synthetic Bone Graft Mixed with Allograft Stem Cell Product in Lumbar Interbody Fusions

Abstract

Background: Over 400,000 spine fusions are performed in the United States annually with 75% involving the lumbar region.1 It is the indicated treatment of many chronic orthopedic conditions that fail conservative management. There are numerous surgical approaches; however, common to all is the removal of the intervertebral disc and the insertion of a bone graft which promotes arthrodesis. Iliac crest autografts are regarded as the “gold standard” bone graft material for lumbar fusions. SurGenTec has developed an allogeneic graft, Vimax®, that has illustrated similar qualities to autograft material. This study aims to observe how the mixture of Vimax® and OsteoFlo® will affect the rate of arthrodesis in patients undergoing lumbar fusions. Methods: A retrospective chart review on patients that received a lumbar interbody fusion using Vimax® and Osteoflo® between May 2021 to July 2022 was performed. Demographic information was obtained. Pre-operative radiographs were measured in addition to 2-week, 6-week, 3-month, 6-month, and 1-year post-operative radiographs. Post-operative radiographs were also assigned a Bridwell fusion grade. Results: 96 patients receiving 146 fusions were studied. 23.3% of fusions recorded a Bridwell Grade I (complete fusion) at 3-months post-op and 92.8% at 1-year post-op. The comorbidities of heart disease and hypertension displayed delayed arthrodesis at 6 months and 3 months post-op, respectively. However, both had over 90% Bridwell Grade 1 at 1-year post-op. No significant difference was noted for surgical approach or other comorbidities such as diabetes mellitus, osteoporosis, and renal disease. Segmental lordosis, pelvic tilt, pelvic incidence, and PI-LL mismatch had no significant difference post-op compared to pre-op. Anterior and posterior disc height and foraminal height increased significantly while spondylolisthesis decreased significantly post-operatively. Lumbar lordosis displayed a significant decrease at 2-weeks post-op compared to pre-op, but not at any other timepoint. Conclusions: Vimax® and OsteoFlo® demonstrated effectiveness as an iliac crest autograft substitute.