1519. Comparing the Surgical Outcomes of Stem Cell Allografts versus Non-Stem Cell Allografts in Spinal Fusion

Authors: Mohamad Bydon, MD, FAANS ; Aya Akhras, MBBS; Waseem Wahood, MS; Mohammed Alvi, MBBS; Anshit Goyal, MBBS (Rochester, MN)

Introduction:

For decades, autogenous iliac crest bone graft (ICBG) has been considered the “gold standard” graft material for successful spinal fusion. However, it is associated with a high complication rate, and requires an additional incision to obtain a limited amount of autograft. In recent years, many alternatives to ICBG such as, stem cell allografts (SCA) and other osteobiologic technologies have been identified. We present a comprehensive review of the literature, exploring the differences in clinical outcomes between SCAs and non-stem cell allografts (NSCAs) in spinal fusion surgery.

Methods:

A comprehensive literature search for cervical and lumbar fusions including type of graft, spanning four databases using Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines, was conducted from 1981 through 2018, in English only. Patients undergoing spinal fusion with SCAs were compared to patients undergoing spinal fusion with NSCAs for fusion rate at 12 month follow-up (effect size, ES).

Results:

Thirty-one studies (n=2741) reporting fusion rates were included for analysis. Of these, 7 studies and 402 patients were in the SCA group, while 23 studies and 2339 patients were in the NSCA group. One study directly compared SCAs and NSCAs. SCA group includes stem-cell allografts, while NSCA group includes: local autograft, ICBG, cadaveric allograft, grafts mixed with bone morphogenic protein(BMP), and mixtures of allografts and autografts. Upon statistical analysis, we found that there was no significant difference in fusion rates at 12 month follow-up(p=0.524) between SCAs(ES:0.92, 95%CI:0.87-0.96) compared to NSCAs(ES:0.89, 95%CI:0.85-0.93) in spinal fusion.

Conclusion:

Both stem cell and non-stem cell grafts appear to confer equivalent fusion rates in patients receiving spinal fusion. We anticipate that our analysis will encourage further studies using stem cell grafts, including a careful evaluation of their efficacy in certain clinical populations, where fusion might be difficult to achieve, such as patients with osteoporosis.