Retrograde ejaculation after anterior lumbar interbody fusion using rhBMP-2: a cohort controlled study

Background ContextThe commercially available growth factor recombinant bone morphogenic protein-2 (rhBMP-2) used in spinal fusion has been associated with numerous adverse reactions, including inflammatory reactions in soft tissue, heterotopic bone formation, radiculitis, osteolysis, and cage or graft subsidence. The original Food and Drug Administration Summary of anterior lumbar interbody fusion (ALIF) reported 12 retrograde ejaculation (RE) events (8%) in the rhBMP-2 groups compared with (1.4%) in the control group. It had been debated whether this finding was related to rhBMP-2 use.PurposeTo compare the incidence of RE after ALIF in patients with and without rhBMP-2 use.Study designRetrospective analysis of prospectively gathered outcomes data on consecutive subjects having ALIF with and without rhBMP-2 use.Patient sampleMale patients with lumbar spondylosis or spondylolisthesis having ALIF of the lowest one or two lumbar levels with and without rhBMP-2.Outcome measureReport of RE as a new finding after ALIF.MethodsFrom the comprehensive outcome database at a high-volume university practice, male subjects having ALIF for one- (L5/S1) or two-level (L4/L5, L5/S1) lumbar fusion were identified. Retrograde ejaculation events were recorded and comparative incidence compared.ResultsThe two groups were comparable for age and additional procedures performed. There were 69 L5/S1 ALIFs performed with rhBMP-2 and 174 ALIFs performed without rhBMP-2 during the study period. Of those, 24 and 64 were two-level ALIFs performed with and without rhBMP-2, respectively. There were five RE events (7.2%) reported in the rhBMP-2 group and 1 (0.6%) in the control group. Comparing single-level L5/S1 ALIF, there was a 6.7% and 0% rate of RE in the rhBMP-2 versus control groups, respectively. At 1 year after surgery, three of six affected subjects reported resolution of the RE.ConclusionThis study confirms previous reports of a higher rate of RE in ALIF procedures using rhBMP-2. This may be an important consideration in subjects concerned with sterility after surgery.