Treatment of Chronic Low Back Pain via Ablation of the Basivertebral Nerve: Results of the Smart Trial

Document Type

Article

Publication Date

10-2017

Abstract

BACKGROUND CONTEXT: Chronic low back pain is a major source of disability in the United States and throughout the world. Traditional treatments such as conservative care, opioids, injection therapy, lumbar fusion and lumbar disc replacement have shown variable results. The INTRACEPT Intraosseous Nerve Ablation System is the first targeted therapy to relieve chronic low back pain in the presence of Modic type 1 or 2 abnormalities by denervating the nociceptive pain signaling within the vertebral body (VB). The Intracept System uses bipolar radio frequency (RF) energy to ablate the basivertebral nerve (BVN), delivered by a minimally invasive, transpedicular approach. The BVN is an intraosseous sensory nerve within the vertebral body, whose role in afferent pain transmission is thought to be a source of chronic axial low back pain associated with degenerative VBs or VB endplates.

PURPOSE: Determine the effectiveness of RF ablation of the BVN for relief of chronic low back pain.

STUDY DESIGN/SETTING: Prospective, randomized, double-blinded sham control

PATIENT SAMPLE: Skeletally mature patients with chronic (>6 months), isolated low back (lumbar) pain and no neurogenic leg pain, who had not responded to at least six months of nonoperative management (conservative care) were eligible for the SMART study. Recent MRI had to demonstrate either Type 1 or 2 Modic changes at 3 or less contiguous vertebral bodies.

OUTCOME MEASURES: ODI, safety

METHODS: A total of 225 patients at 18 sites were enrolled in this prospective, double-blinded, randomized, sham controlled SMART study; 147 patients were randomized to the Intracept System arm (received treatment); 78 were randomized to the Sham arm (received sham surgery). Followup was at 2 and 6 weeks, 3,6 and 12 months. Both the patients and the physicians providing postoperative care were unaware of the treatment assignment until the conclusion of the one-year follow-up. For Sham patients, there was an optional crossover component after all 12-month evaluations were performed.

RESULTS: Targeting success (assessed by postop MRI) was achieved in 300 of the 317 treated and evaluated vertebral bodies (94.6%) or in 129 of 145 patients (89.0%). Results of the primary end point analysis for the per protocol (PP) population at 3 months showed that the ODI improvement observed in the Intracept arm was statistically superior to the Sham arm (p=.019). The mean improvement in ODI in the Intracept patients (PP population) at 3 months was 20.5 points, twice the 10-point MCID for ODI as recognized in the published literature. This result was sustained through two years of follow-up. Furthermore, an analysis of ODI responder rates found that 75.6% of patients treated with the Intracept System demonstrated a greater than 10-point, clinically meaningful improvement in their low back pain and associated disability at 3 months. There were no unanticipated adverse device effects. MRI evaluations at the 6-week and 6-month follow-up time points found no evidence of any spinal cord abnormalities, avascular necrosis or accelerated disc degeneration.

CONCLUSIONS: The Intracept System is safe, well tolerated, and effective for the treatment of chronic low back pain in this patient population. This conclusion is based on the results of the analysis of the primary study end point that showed a significantly greater improvement in ODI for the Intracept System arm over the sham arm in the PP population. Furthermore, the treatment procedure has a high degree of procedural success and is generally safe, as evidenced by the relatively low rates and severities of device and procedure related adverse events.

FDA DEVICE/DRUG STATUS: INTRACEPT Intraosseous Nerve Ablation System (Approved for this indication).

Comments

Annual Meeting of the Lumbar Spine Research Society, Chicago, IL, April 6-7, 2017.

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