Background context:

Recombinant human bone morphogenetic protein-2 (BMP-2) is the growth factor with the most striking osteoinductive performance in orthopedic operations; it is also able to induce heterotopic bone formation. However, there has been little clinical research on Escherichia coli-derived BMP-2 (E.BMP-2).

Purpose:

To confirm the efficacy and safety of E.BMP-2 with a hydroxyapatite carrier when applied to one-sided posterolateral fusion (PLF) in addition to lumbar interbody fusion (LIF), and to measure the lower dose of E.BMP-2 ever reported achieving solid fusion.

Study design/setting:

Retrospective case-control study PATIENT SAMPLE: A total of 121 patients who received surgery for 1 or 2 levels of fusion for lumbar degenerative spinal stenosis or spondylolisthesis from January 2009 to December 2019 were included.

Outcome measures:

Clinical and functional outcomes were evaluated using preoperative and final follow-up visual analogue scales for back pain (VAS-BP) and leg pain (VAS-LP), and Korean Oswestry disability index (K-ODI) scores. Fusion rates were evaluated by computed tomography at six months and one year after surgery. In addition, a subgroup analysis of group E according to number of fusion levels was conducted, and the fusion rates in the one-level and two-level fusion groups were compared.

Methods:

LIF and additional one-sided PLF was performed in all patients. They received autogenous iliac bone grafts (Group C, n=69) or 1mg of E.BMP-2 (Group E, n=52).

Results:

There were no significant differences between preoperative and final VAS-BP, VAS-LP and K-ODI. The PLF rate was 79.7% for Group C and 82.7% for Group E at postoperative six months, and 94.2% for Group C and 100% for Group E at postoperative one year (P = 0.679, 0.134, respectively). The LIF rate was 71.0% in Group C and 71.2% in Group E at six months after surgery, and 97.1% in Group C and 100% in Group E at one year (P = 0.987, 0.506, respectively). In terms of numbers of fusion levels in Group E, PLF rates at six months (P = 0.486) and one year after surgery were similar in the two groups, as were LIF rates at six months (P = 0.822) and one year after surgery. There were no cases of malignancy or radiculopathy in Group E during one-year of follow-up.

Conclusions:

One milligram of E.BMP-2 is a safe and effective osteoinductive material in short-level lumbar PLF surgery.