A Retrospective Chart Assessment of Clinical Outcomes after Amniotic Suspension Allograft Is Used during Spinal Arthrodesis Procedures

Study Design: This retrospective, non-randomized study was designed to evaluate one-year clinical outcomes in a cohort of patients treated with an amniotic suspension allograft as an adjunct to lumbar interbody fusion. Methods: A single-center chart review was conducted to collect pre-operative and peri-operative data for patients at or beyond the one year post-operative time point. Results: Patients underwent either anterior (n = 22) or posterior (n = 65) lumbar interbody fusion. There were six reoperations reported: pseudarthrosis repair (n = 1), adjacent level decompression (n = 2), removal of symptomatic instrumentation (n = 3). Overall VAS score improved from 7.8 ± 1.7 to 5.5 ± 2.4 at 1 year post-op (n = 86, p = 0.0001) and overall ODI score improved from 55 ± 16 to 42 ± 19 at 1 year post-op (n = 85, p = 0.0001). Patients that were 59 years old or older at the time of surgery reported greater improvement in VAS score (3.6 ± 2.3 point improvement, n = 31) than patients younger than 59 at the time of surgery (1.7 ± 2.2 point improvement, n = 55, p = 0.0005). There was not a significant difference in outcome measures between groups when the data were stratified based on patient BMI, tobacco use, previous surgery, or a primary indication of pseudarthrosis repair. Conclusions: These results indicate that there is a significant clinical improvement when amniotic suspension allograft is used during interbody fusion. Patient groups with increased risk of non-union (increased age, previous pseudarthrosis, and tobacco users) demonstrated improvement in one year post-op outcome measures. Improved clinical outcome implies a high rate of successful arthrodesis in both high and low risk patient populations.