Chronic Low Back Pain: Restoration of Dynamic Stability.

ABSTRACT

OBJECTIVES: Electrical stimulation for multifidus muscle contraction is a novel approach for treating chronic low back pain (CLBP). A multicenter, open-label feasibility study investigated this modality in patients with continuing CLBP despite medical management and no prior back surgery and no known pathological cause of CLBP. METHODS: Twenty-six patients with continuing CLBP despite physical therapy and medication were implanted with commercially-available implantable pulse generators and leads positioned adjacent to the medial branch of the dorsal ramus as it crosses the L3 transverse process such that electrical stimulation resulted in contraction of the lumbar multifidus (LM) muscle. Patients self-administered stimulation twice daily for 20 min. Low back pain (VAS), Oswestry Disability Index (ODI) and Quality of Life (EQ-5D) scores were collected at three and five months and compared to baseline. Stimulation was withdrawn between months 4 and 5 to test durability of effect. RESULTS: At three months, 74% of patients met or exceeded the minimally important change (MIC) in VAS and 63% for disability. QoL improved in 84% of patients (N = 19) and none got worse. Five of the 11 patients on disability for CLBP (45%) resumed work by three months. Half the patients reported ≥50% VAS reduction by month 5. Twenty-one lead migration events occurred in 13 patients, of which 7 patients are included in the efficacy cohort. CONCLUSIONS: Episodic stimulation to induce LM contraction can reduce CLBP and disability, improve quality of life and enable return to work. A dedicated lead design to reduce risk of migration is required.