P119. Adjunctive use of bone growth stimulation in cervical spine fusion patients at risk for pseudarthrosis

BACKGROUND CONTEXT Multi-level disease, prior failed fusion, diabetes, nicotine use, and osteoporosis are factors that may decrease the likelihood of a successful cervical spine fusion, the result of which leads to prolonged pain, reduced function, and overall decreased quality of life. Studies have shown that adjunctive use of pulsed electromagnetic field (PEMF) stimulation can be used to improve spine fusion rates, particularly in subjects that are at risk for pseudarthrosis. PURPOSE The purpose of this study was to evaluate the cervical spine fusion status in subjects with one or more risk factors for non-union that received PEMF treatment compared to subjects that did not receive PEMF treatment. STUDY DESIGN/SETTING A prospective multicenter clinical trial (NCT 03177473) was conducted at 11 clinical sites across the US. Additionally, a retrospective cohort was used as a control arm. PATIENT SAMPLE Data from a multi-center prospective study of subjects that underwent cervical spine fusion and were treated with PEMF was compared to a “matched” retrospective cohort of subjects that underwent cervical spine fusion and were not treated with PEMF. In the prospective arm of this study, subjects undergoing cervical spinal fusion surgery were identified for enrollment based on having 1 or more of the following risk factors for pseudoarthrosis: multilevel (2 or more levels) fusion, prior failed cervical spine fusion, diabetes, osteoporosis, or nicotine use. OUTCOME MEASURES The primary outcome measure was fusion status at the 12-month followup period. Fusion status was determined using anterior/posterior, lateral, and flexion/extension radiographs and computed tomography (without contrast). METHODS Subjects in the treated group were required to wear the PEMF device for 4 hours/day for 6 months postop. Compliance was measured based on usage data downloaded from the device. RESULTS Both cohorts had similar gender and BMI characteristics (treated group was 53.8% female vs 55.3% female for control; treated group had a BMI of 30.0kg/m2 vs 30.2kg/m2 for control). The treated group was older compared to control (61.0yr and 55.9yr respectively, p<0.05). At baseline, subjects in the PEMF treated group had a significantly higher number of risk factors for nonunion (1.8 for treated group vs 1.1 for control, p<0.001), and significantly higher number of surgical levels (2.8 for treated group vs 2.0 for control, p<0.005). At 12-months postop, subjects in the PEMF treated group (n=161) had a 90.1% fusion rate, compared to a 65.4% fusion rate for the control group (n=26) (p<0.001). CONCLUSIONS Adjunctive use of PEMF stimulation provides significant improvements in cervical spine fusion rates in subjects having risk factors for pseudarthrosis. When compared to control subjects that did not use PEMF stimulation, treated subjects had improved fusion outcomes despite being older, having more risk factors for pseudarthrosis, and undergoing more complex surgeries. FDA Device/Drug Status CervicalStim (Approved for this indication) Multi-level disease, prior failed fusion, diabetes, nicotine use, and osteoporosis are factors that may decrease the likelihood of a successful cervical spine fusion, the result of which leads to prolonged pain, reduced function, and overall decreased quality of life. Studies have shown that adjunctive use of pulsed electromagnetic field (PEMF) stimulation can be used to improve spine fusion rates, particularly in subjects that are at risk for pseudarthrosis. The purpose of this study was to evaluate the cervical spine fusion status in subjects with one or more risk factors for non-union that received PEMF treatment compared to subjects that did not receive PEMF treatment. A prospective multicenter clinical trial (NCT 03177473) was conducted at 11 clinical sites across the US. Additionally, a retrospective cohort was used as a control arm. Data from a multi-center prospective study of subjects that underwent cervical spine fusion and were treated with PEMF was compared to a “matched” retrospective cohort of subjects that underwent cervical spine fusion and were not treated with PEMF. In the prospective arm of this study, subjects undergoing cervical spinal fusion surgery were identified for enrollment based on having 1 or more of the following risk factors for pseudoarthrosis: multilevel (2 or more levels) fusion, prior failed cervical spine fusion, diabetes, osteoporosis, or nicotine use. The primary outcome measure was fusion status at the 12-month followup period. Fusion status was determined using anterior/posterior, lateral, and flexion/extension radiographs and computed tomography (without contrast). Subjects in the treated group were required to wear the PEMF device for 4 hours/day for 6 months postop. Compliance was measured based on usage data downloaded from the device. Both cohorts had similar gender and BMI characteristics (treated group was 53.8% female vs 55.3% female for control; treated group had a BMI of 30.0kg/m2 vs 30.2kg/m2 for control). The treated group was older compared to control (61.0yr and 55.9yr respectively, p<0.05). At baseline, subjects in the PEMF treated group had a significantly higher number of risk factors for nonunion (1.8 for treated group vs 1.1 for control, p<0.001), and significantly higher number of surgical levels (2.8 for treated group vs 2.0 for control, p<0.005). At 12-months postop, subjects in the PEMF treated group (n=161) had a 90.1% fusion rate, compared to a 65.4% fusion rate for the control group (n=26) (p<0.001). Adjunctive use of PEMF stimulation provides significant improvements in cervical spine fusion rates in subjects having risk factors for pseudarthrosis. When compared to control subjects that did not use PEMF stimulation, treated subjects had improved fusion outcomes despite being older, having more risk factors for pseudarthrosis, and undergoing more complex surgeries.