Bone graft materials for posterolateral fusion made simple: a systematic review

Abstract

Background: Iliac crest has long been the gold standard for lumbar fusion, but concerns over donor site morbidity have led to a wide variety of bone graft substitutes. Despite prolific research, a general consensus is yet to be reached on bone graft materials that lead to optimal fusion.

Purpose: The purpose of this review is to evaluate the current literature for bone graft material options that maximize fusion rate in posterolateral lumbar fusion surgery.

Design: Systematic Review.

Methods: A PRISMA-compliant systematic review of PubMed, EMBASE, and the Web of Science was conducted. Included studies were published from January 2000 to July 2015, were clinical human research studies involving available autograft, allograft, or synthetic bone graft options in posterolateral lumbar spine fusion, and reported radiographic fusion rate as a primary end outcome. This research had no funding source and the authors have no conflicts to declare.

Results: 81 articles underwent full-text review, and 48 were included in this study. 18 studies assessed fusion rate by plain radiographs alone (37.5%), while 6 used CT scan (12.5%), and 24 used both (50.0%). 45 studies looked at ICBG in conjunction with LAG (29), BCP(1), APC (2), BMPs (6), or DBM (1). Aggregate mean fusion rates among these ranged from 68.0 to 91.5%. 22 studies evaluated fusion rates of LAG, either isolated (3) or combined with ceramic extenders (8), DBM (4), BMP (1), BMA (4), APC (1), or ICBG(1). Aggregate mean fusion rate ranged from 75 to 95.5%. With the exception of studies involving allograft (mean fusion rate 40.0%), the mean fusion rate for all other graft combinations exceeded 70.0%.

Conclusions: While our results find that LAG+BMA provided highest fusion rate, most material options analyzed in this study provide comparable fusion outcomes. The ideal graft option must incorporate a combination of materials with osteoconductive, osteoinductive, and osteogenic properties. Our results represent the robust and dynamic nature of the current state of lumbar graft technology. These slides can be retrieved under Electronic Supplementary Material.

Keywords: Allograft; Autograft; Bone graft; Bone marrow; Ceramics; Collagen; Graft materials; Growth factors; Posterolateral lumbar fusion.