A retrospective, controlled trial evaluation of pulsed electromagnetic field stimulation for fusion success following lumbar spinal surgery

Background Spinal surgeries have become common procedures due to greater life expectancy and the increasing elderly population. Failed fusion, or nonunion, may be influenced by patient risk factors and can lead to a myriad of complications. Pulsed electromagnetic field (PEMF) stimulation is a noninvasive post-operative adjunct therapy that has been shown to influence underlying cellular processes that may improve osteogenesis to promote successful fusion following spinal surgery. The aim of the study was to evaluate the effect of PEMF on lumbar fusion in patients with risk factors for nonunion. Methods The current study employed a prospective, multicenter study to investigate PEMF as an adjunct therapy following lumbar spinal fusion procedures in subjects with risk factors for failed fusion. A retrospective control arm was used as a comparator. Subjects were enrolled with at least one of the following risk factors: prior failed fusion, multi-level fusion, nicotine use, osteoporosis, advanced age (>65 years), body mass index >30 kg/m2, and diabetes. PEMF was delivered for 6-months following surgery. Overall fusion status and influence of risk factors were assessed. Successful fusion was determined by radiographic imaging. Results Fusion status was compared at a 12-month follow-up in subjects treated with PEMF (n=142) vs. control (n=47). Successful fusion was observed in 88.0% (n=125/142) of PEMF subjects and 68.1% (n=32/47) of control subjects. PEMF therapy resulted in statistically improved fusion rates in subjects with prior failed fusion (P=0.04), multi-level fusion surgery (P<0.001), and advanced age (P<0.001) when compared to control. PEMF therapy resulted in statistically improved fusion rates in subjects who had at least one risk factor (P=0.002), ≥2 risk factors (P<0.001), and ≥3 risk factors (P=0.003) compared to control. Linear regression analyses showed a significant treatment effect of PEMF across all risk factors and presentations (P=0.003). A favorable safety profile was observed with PEMF therapy. Conclusions PEMF therapy improved fusion success in subjects following lumbar spinal surgery and represents a beneficial adjunct treatment resulting in significant improvements in subjects having risk factors for nonunion.