Restorative Neurostimulation of the Multifidus for Chronic Low Back Pain After Prior Lumbar Spinal Surgery: A Single-Center, Consecutive Case Series.

Objectives: Restorative neurostimulation of the lumbar multifidus muscle is a novel therapy for chronic nonspecific low back pain (CLBP). Previous studies have excluded patients with prior lumbar surgery. In this study, we describe outcomes in patients with CLBP after prior lumbar surgery.

Materials And Methods: This was a single-center, consecutive case series. The primary outcome measure was the change from baseline numeric rating score (NRS) for low back pain (LBP) and Oswestry Disability Index (ODI) in the first 12 months after treatment. Secondary outcomes were number of patients having minimal clinically important difference (MCID) in NRS and ODI scores, Short Assessment of Patient Satisfaction with their management, relationships between type of prior surgery and outcome, and incidence of adverse events.

Results: The cohort comprised 26 patients (12 men; 14 women; mean age 56 years) who had their lumbar surgery a mean 6.9 years previously; 16 were followed up for 12 months and nine for >six months. One patient (3.6%) had a postoperative infection and required device removal. Both mean ODI and LBP NRS and their 95% CIs decreased serially from baseline 41.8 (36.5-46.5) to 29.3 (22.1-36.6) at six months and 28.1 (21.8-34.4) at 12 months (ODI), and from 6.4 (5.5-7.0), 3.8 (3.1-4.6) and 3.6 (2.5-4.7), respectively, for NRS. Patient levels of satisfaction with treatment were very high. MCIDs were observed in ten patients (40%) who experienced improvement in both their ODI (by >10) and NRS (by >2), and in ten patients who experienced improvement in one of these variables but not the other. The type of prior lumbar surgery did not influence outcomes. There were no device-related complications.

Conclusions: The early outcome profiles after restorative neurostimulation after lumbar spinal surgery are similar to those reported in patients without prior surgery. Further prospective clinical studies are required to establish the validity of these findings.