Percutaneous Peripheral Nerve Stimulation for Chronic Low Back Pain: Prospective Case Series With 1 Year of Sustained Relief Following Short-Term Implant

Abstract

Introduction: Percutaneous peripheral nerve stimulation (PNS) provides an opportunity to relieve chronic low back pain and reduce opioid analgesic consumption as an alternative to radiofrequency ablation and permanently implanted neurostimulation systems. Traditionally, the use of neurostimulation earlier in the treatment continuum has been limited by its associated risk, invasiveness, and cost.

Methods: Percutaneous PNS leads (SPRINT MicroLead) were placed bilaterally to target the medial branches of the dorsal rami nerves under image guidance. The percutaneous leads were connected to miniature wearable stimulators (SPRINT PNS System) for the 1-month therapy period, after which the leads were removed. Pain and disability were assessed long-term up to 12 months after lead removal.

Results: Substantial, clinically significant reductions in average pain intensity (≥50% reduction as measured by the Brief Pain Inventory Short Form) were experienced by a majority of subjects (67%) at end of treatment compared to baseline (average 80% reduction among responders; P < 0.05, analysis of variance; n = 9). Twelve months after the end of PNS treatment, a majority of subjects who completed the long-term follow-up visits experienced sustained, clinically significant reductions in pain and/or disability (67%, n = 6; average 63% reduction in pain intensity and 32-point reduction in disability among responders). No serious or unanticipated adverse events were reported.

Conclusions: This study challenges the long-held notion that a positive trial of PNS should be followed by a permanent implant in responders. Percutaneous PNS may serve as an effective neurostimulation therapy for patients with chronic low back pain and should be considered earlier in the treatment continuum as a motor-sparing means of avoiding opioids, denervation, and permanently implanted neurostimulation systems.

Keywords: chronic pain; disability; low back pain; percutaneous peripheral nerve stimulation.

Figure 1

Percutaneous peripheral nerve stimulation (PNS) lead used for treatment of chronic low back pain (LBP). Percutaneous PNS was delivered using a coiled, fine‐wire MicroLead (SPR Therapeutics, Inc.) for 1 month for the treatment of chronic LBP. Figure used with permission from SPR Therapeutics, Inc.

Figure 2

Anatomical target of percutaneous peripheral nerve stimulation lead placement for treatment of chronic low back pain. Percutaneous fine‐wire leads (SPRINT MicroLead, SPR Therapeutics, Inc.) were placed to target the medial branch (MB) of the dorsal ramus, medial and inferior to the facet joint in the center of the region of pain. Selective activation of the multifidus (MF) overlapping the area of pain confirmed appropriate lead placement. A cross‐sectional view of the lumbar paraspinal anatomy is shown, with the lead and introducer placed targeting the MB of the dorsal ramus. AP, articular process; IL, iliocostalis; LS, longissimus; SP, spinous process; TP, transverse process.

Figure 3

Average pain intensity among responders over time. Subjects experiencing a clinically significant reduction in pain at the end of treatment (≥ 50% reduction) continued to experience sustained results long term, through at least 12 months after the end of peripheral nerve stimulation (PNS) treatment. The average reduction among responders 1 year after end of treatment with PNS was 63%. BPI‐5, Brief Pain Inventory Short Form.

Figure 4

Oswestry Disability Index results among responders over time. Subjects experiencing a clinically significant reduction in disability (≥ 10 points) continued to experience sustained results long term, through at least 12 months after the end of peripheral nerve stimulation (PNS) treatment. The average reduction in disability among responders 1 year after the end of treatment with PNS was 32 points. A 10‐point improvement in the Oswestry Disability Index score is considered clinically significant.