Options: A Prospective, Open-Label Study of High-Dose Spinal Cord Stimulation in Patients with Chronic Back and Leg Pain

Abstract

Background: Therapeutic approaches to spinal cord stimulation (SCS) continue to evolve and improve patient outcomes in patients receiving SCS therapy secondary to failed back surgery syndrome.

Objectives: The aim of this study was to evaluate pain relief and other patient outcomes of SCS using selected high-dose programming parameters.

Study design: This was a prospective cohort study.

Setting: This study took place at 11 centers in North America.

Methods: Forty-four SCS-naive patients underwent trialing, starting with 1,000 Hz frequency, 90 µs pulse width followed by 300 Hz frequency, 800 µs pulse width, if pain relief was inadequate. Patients with 50% or greater pain relief were eligible for permanent implantation. Patient's pain rating, global impression of change, health-related quality of life, functional disability, satisfaction/recommendation, stimulation perception, device programming, and adverse events were assessed at 3 months postimplant.

Results: There were significant improvements from baseline in mean Numeric Rating Scale (NRS-11) pain scores for overall pain (7.5 to 3.8; P < 0.01), back pain (7.2 to 3.4; P < 0.01), leg pain (7.2 to 3.1; P < 0.01), Oswestry Disability Index (ODI) score (51.5 to 32.1; P < 0.01), and European Quality of Life-Five Dimensions, version 5L score (EQ-5D-5L) (0.58 to 0.74; P < 0.01). Twenty-eight of 32 patients (88%) had significant, favorable improvement in Patient Global Impression of Change (PGIC). Eighty-four percent of patients were "satisfied," and 78.1% would "definitely" recommend SCS. Eighteen patients (56%) used 1,000 Hz frequency and 90 µs pulse width exclusively; these patients experienced mean NRS-11 overall pain score improvement of 4.7 points. Device-, therapy-, or procedure-related adverse events were experienced in 19 patients (40%, 19 of 48), and all events resolved without reoperation and were similar to those observed with traditional SCS systems.

Limitations: There was no active or sham comparator group, and therefore the reported effects may not be solely attributable to therapy effects and may be related to other, nonspecific effects of SCS.

Conclusions: Improvements in pain relief, PGIC, EQ-5D-5L, ODI, and patient satisfaction were all clinically relevant and statistically significant. Future studies are needed to understand how these high-dose parameters perform versus a standard comparator.

Key words: Spinal cord stimulation, high-frequency electrical stimulation, failed back surgery syndrome, neurostimulation, prospective, nonrandomized study.