Wireless high-frequency dorsal root ganglion stimulation for chronic low back pain: A pilot study.

OBJECTIVE: Evaluation of the efficacy of a wireless high-frequency stimulator placed over selected DRG of exiting nerve roots for the treatment of chronic low back pain.

DESIGN: Feasibility.

SUBJECTS: Six subjects with chronic, intractable back pain refractory to standard medical treatment.

METHODS: Four stimulators (Freedom-4A) provided by Stimwave Technologies, were implanted over the DRG exiting nerve roots, bilaterally at both the T9 and L2 vertebral levels. Subjects were asked to evaluate stimulation independently with the devices turned on at T9 and subsequently L2 for each of 2 weeks. Subjects were then monitored for 8 weeks with the preferred stimulator. Pain reduction with the Visual Analog Scale (VAS), functionality with the Oswestry Disability Index (ODI), Patient Global Impression of Change (PGIC) and medication usage were evaluated.

RESULTS: Four subjects preferred T9 stimulation with only one subject preferring stimulation at L2. One subject dropped out of the study before conclusion of the 4-week evaluation and is not included in this report. Average pain levels (n = 5) at 12-week post-implantation decreased with 61% for back pain and 56% for leg pain with a significant reduction in pain medication, including a 100% reduction in opioid pain medications. The average reduction in disability was 12%. Subjects reported an average impression of change of 6 (1 = no change, 7 = great deal better).

CONCLUSIONS: Wireless high-frequency stimulation of the DRG is a viable option to treat chronic low back pain. Preliminary results show a subject preference for stimulation at the T9 vertebral level.