In an attempt to enhance the potential to achieve a solid arthrodesis and avoid the morbidity of harvesting autologous iliac crest bone (AICB) for a lumbar fusion, numerous alternatives have been investigated. The use of these fusion adjuncts has become routine despite a lack of convincing evidence demonstrating a benefit to justify added costs or potential harm. Potential alternatives to AICB include locally harvested autograft, calcium-phosphate salts, demineralized bone matrix (DBM), and the family of bone morphogenetic proteins (BMPs). In particular, no option has created greater controversy than the BMPs. A significant increase in the number of publications, particularly with respect to the BMPs, has taken place since the release of the original guidelines. Both DBM and the calciumphosphate salts have demonstrated efficacy as a graft extender or as a substitute for AICB when combined with local autograft. The use of recombinant human BMP-2 (rhBMP-2) as a substitute for AICB, when performing an interbody lumbar fusion, is considered an option since similar outcomes have been observed; however, the potential for heterotopic bone formation is a concern. The use of rhBMP-2, when combined with calcium phosphates, as a substitute for AICB, or as an extender, when used with local autograft or AICB, is also considered an option as similar fusion rates and clinical outcomes have been observed. Surgeons electing to use BMPs should be aware of a growing body of literature demonstrating unique complications associated with the use of BMPs.
Keywords: ACS = absorbable collagen sponge; AICB = autologous iliac crest bone; ALIF = anterior lumbar interbody fusion; BMA = bone marrow aspirate; CHA = coralline hydroxyapatite; CRM = compression-resistant matrix; DBM = demineralized bone matrix; FRA = femoral ring allograft; HA = hydroxyapatite; ICBG = iliac crest bone graft; IDE = investigational device exemption; NRS = numeric rating scale; ODI = Oswestry Disability Index; OP-1 = osteogenic protein–1; PLIF = posterior lumbar interbody fusion; RCT = randomized controlled trial; SF-36 = 36-Item Short Form Health Survey; TLIF = transforaminal lumbar interbody fusion; VAS = visual analog scale; bone graft; bone morphogenetic protein; bone substitute; fusion; lumbar spine; mJOA = modified Japanese Orthopaedic Association; practice guidelines; rhBMP = recombinant human bone morphogenetic protein; β-TCP = β-tricalcium phosphate.