Surgical treatment of refractory low back pain using implanted BurstDR spinal cord stimulation (SCS) in a cohort of patients without options for corrective surgery: Findings and results from the DISTINCT study, a prospective randomized multi-center-controlled trial

Abstract

Background: Low back pain (LBP) is a highly prevalent, disabling condition affecting millions of people. Patients with an identifiable anatomic pain generator and resulting neuropathic lower extremity symptoms often undergo spine surgery, but many patients lack identifiable and/or surgically corrective pathology. Nonoperative treatment options often fail to provide sustained relief. Spinal cord stimulation (SCS) is sometimes used to treat these patients, but the lack of level 1 evidence limits its widespread use and insurance coverage. The DISTINCT RCT study evaluates the efficacy of passive recharge burst SCS compared to conventional medical treatment (CMM) in alleviating chronic, refractory axial low back pain.

Methods: This prospective, multicenter, randomized, study with an optional 6-month crossover involved patients who were not candidates for lumbar spine surgery. The primary and secondary endpoints evaluated improvements in low back pain intensity (NRS), back pain-related disability (ODI), pain catastrophizing (PCS), and healthcare utilization. Patients were randomized to SCS therapy or CMM at 30 US study sites.

Results: The SCS arm reported an 85.3% NRS responder rate (≥ 50% reduction) compared to 6.2% (5/81) in the CMM arm. After the 6M primary endpoint, SCS patients elected to remain on assigned therapy and 66.2% (49/74) of CMM patients chose to trial SCS (crossover). At the 12M follow-up, SCS and crossover patients reported 78.6% and 71.4% NRS responder rates. Secondary outcomes indicated significant improvements in ODI, PCS, and reduced healthcare utilization. Six serious adverse events were reported and resolved without sequelae.

Conclusion: DISTINCT chronic low back pain patients with no indication for corrective surgery experienced a significant and sustained response to burst SCS therapy for up to 12 months. CMM patients who crossed over to the SCS arm reported profound improvements after 6 months. This data advocates for a timely consideration of SCS therapy in patients unresponsive to conservative therapy.

Keywords: BurstDR; Chronic low back pain burst; DISTINCT RCT; Nonsurgical Low back pain; Passive recharge burst; SCS.

Fig. 1

Consort diagram showing subject disposition from enrollment through 12 months.

Fig. 2

Reduction in NRS score. (A) The average ± SD NRS score for SCS decreased from 7.7±1.2 at baseline to 2.3±1.8 at 6M and sustained at 2.5±2.2 at 12 months. Patients randomized to the CMM did not report a significant decrease at baseline (7.9±1.1) or at 6M (7.4±1.8). Post crossover, the 6M scores decreased to 3.1±2.2. (B) 78.6% of SCS patients reported a 50% decrease in NRS at 12M with 40.8% reporting an 80% substantial decrease. In contrast, only 6.2% of the CMM group reported a 50% decrease in NRS at 6M with 71% reporting a 50% decrease in NRS after crossover. About 21.4% reported an 80% substantial decrease at 12M.

Fig. 3

Backpain disability changes. (A) The percent ± SD ODI score for SCS decreased from severe-moderate disability to moderate-minimal disability after 3M. The effect was sustained through 12M (Average score: 52.5±13.8 at baseline to 24.1±13.6 at 12 months). Patients randomized to the CMM reported severe-moderate disability at 6M (53.6±18.1). Post crossover, patients reported moderate-minimal disability with an average ± SD ODI score of 29.5±18.2. (B) 77.2% of SCS patients reported a ≥13 decrease in ODI at 12M in line with the improvement observed from the functional component (79.3%). In contrast, only 27.2% of the CMM group reported a ≥13 decrease in ODI at 6M with 69% reporting a ≥13 decrease in ODI after crossover. 69% reported functional improvement at 12M.

Fig. 4

Catastrophizing changes. The average ± SD PCS score for SCS decreased from 27.6±13.6 at baseline to 7.7±10.2 after 12 months. The CMM group did not observe a significant change within the first 6 months. After cross-over, the average±SD PCS score decreased from 27.5±12.5 at baseline to 12.0±11.0 at 12 M. Both groups reported scores below the population norm (13.9).

Fig. 5

Quality of Life/Activities of Daily Living. Improvement in functional ability is denoted by an increase in score. Improvements in symptoms are denoted by a reduction in score. Patients reported improvements from mild to normal levels for physical function (A) and social function (B). Patients reported a reduction to normal limits for pain interference (C), depression (D), fatigue (E), sleep disturbance (F), and anxiety (F). Patients originally reported baseline levels within mild-moderate symptoms.

Fig. 6

(A) At 6M, 88.2 of SCS patients were very satisfied/satisfied with assigned therapy. About 71% of CMM patients reported dissatisfaction with their conservative therapy however, 6M after cross-over, 77% indicated they were very satisfied/satisfied with the new treatment (B). SCS (88.8%) and crossover patients (79.6%) indicated their conditions significantly improved with therapy at 12 M.