Adjuncts in posterior lumbar spine fusion: comparison of complications and efficacy

The purpose of this study was to define the efficacy of recombinant human Bone Morphogenetic Protein-2 (rhBMP-2) and Demineralized Bone Matrix (DBM) compared to autograft in posterior lumbar spine fusion by comparing complication rates.

During a 7-year period (2003-2009), all patients undergoing posterior lumbar fusion were retrospectively evaluated within a large orthopedic surgery private practice. Patient demographics, comorbidities, number of levels, type of surgery, and types of bone void filler and osteobiologics were analyzed. Complications were defined as reoperation secondary to failed symptomatic fusion, hyper-reaction with fluid collections, bone overgrowth, and infections.

1,398 patients were evaluated with 41.1 % males and 58.9 % females. Mean age was 60 years and BMI 30.6 kg/m². Patients were subdivided in treatment groups: rhBMP-2, 947 (67.7 %), DBM 306 (21.9 %), and autograft 145 (10.4 %). The overall infection rate was 2.1 %. No significant differences were found between the three groups. The incidence of seroma formation was higher in the BMP group (3.2 %) than in the DBM or autograft group (2.0 and 1.4 %, respectively) but this was not significant (p = 0.286 and p = 0.245, respectively). 103 patients (7.4 %) underwent redo surgery for clinically significant nonunion. We found significantly fewer nonunions (4.3 %) in the rhBMP-2 group (p < 0.001) compared to the DBM or autograft group (13.1 and 15.2 %, respectively).

ICBG is the gold standard. DBM leads to comparable fusion rates and does not increase infection or seroma formation. rhBMP-2 supplementation instead of ICBG or bone marrow aspirate results in higher fusion rates compared to autograft alone or autograft plus DBM.