Clinical and radiographic outcomes of concentrated bone marrow aspirate with allograft and demineralized bone matrix for posterolateral and interbody lumbar fusion in elderly patients.

Purpose: Cell-based therapies such as concentrated bone marrow aspirate (BMA) with allograft and demineralized bone matrix (DBM) have been developed as a potential alternative to iliac crest bone graft (ICBG) in spinal fusion. BMA contains mesenchymal stem cells (MSCs) and growth factors that confer osteogenic and osteoinductive potential to osteoconductive scaffolds like allograft and DBM. It is well established that there is an age-related decline in bone marrow MSC population and efficacy. This might be problematic in spine arthrodesis when utilizing BMA derived from elderly patients as a fusion aide. The goal of this study was to describe the outcomes of concentrated BMA with allograft and DBM in elderly patients undergoing posterolateral and interbody lumbar fusion.

Methods: Thirty-one patients, age 65 and older, with a minimum of 12 months follow-up underwent combined primary posterolateral and transforaminal lumbar interbody fusion. Radiographic fusion, complications, reoperation rates and clinical outcomes were assessed. Multiple logistic regression analysis was used to examine the effects of variables such as patient age, gender, smoking, osteoporosis, Charlson co-morbidity index score, single versus multilevel fusion, length of hospital stay, and length of follow-up time on fusion outcome.

Results: The overall rate of a solid fusion (i.e. the concomitant presence of solid posterolateral and interbody fusion in a patient) was 83.9 % (26/31). Specifically, radiographic evidence of a successful posterolateral fusion was 83.9 % (26/31) while the radiographic evidence of a successful interbody fusion was 96.8 % (30/31). Using logistic regression analysis, none of the variables of interest had an association with non-solid unions. One (3.2 %) patient developed a seroma and one (3.2 %) patient developed clinical pseudarthrosis. None of the patients developed hardware-related complications or graft donor site morbidities. Five (16.1 %) patients required reoperation. Excellent or good results were achieved in 83.9 % of patients.

Conclusions: Despite the concerns of reduced fusion potential in elderly patients, autologous concentrated BMA mixed with allograft and DBM in posterolateral and interbody fusions can achieve successful fusion rates with good clinical outcomes and low complication rates.