Radiofrequency ablation of the basivertebral nerve may lead to significant short-term reduction in pain and functional disability in patients with chronic low back pain and type I or type II Modic changes of the vertebral bodies, according to findings from a randomized trial published in the European Spine Journal.
The investigators targeted the basivertebral nerve in this minimally invasive treatment strategy, as it innervates nociceptors thought to be involved in chronic low back pain.
Patients with chronic low back pain (≥ 6 months) were randomly assigned to undergo radiofrequency ablation of the basivertebral nerve (n=147) or a sham procedure (n=78). Three months post-intervention, patients were asked to fill out the Oswestry Disability Index (ODI) questionnaire. The baseline average ODI score was 42 on a 0 to 100 scale, representing severe disability and pain and a negative impact on daily activities.
Levels of back pain were evaluated at baseline and during the study period with the visual analog scale (VAS). Changes in Modic type presentation (L3 through S1) were assessed at 6 weeks and 6 months. Change in ODI at 3 months, compared with baseline, was the study’s primary outcome. Assessments were conducted at 2 and 6 weeks as well as at 3, 6, and 12 months after treatment.
Patients who received radiofrequency ablation had a greater decrease in ODI score at 3 months than those who underwent sham procedure (20.5 points vs 15.2 points, respectively; P =.019). A greater percentage of those who had radiofrequency ablation experienced a clinically meaningful postoperative 3-month improvement in functional disability score (75.6% vs 55.3%, respectively).
The ablation intervention was also associated with greater least squares mean improvements in back pain at 3, 6, and 12 months compared with the sham intervention, as assessed with the VAS (2.97 cm, 3.04 cm, and 2.84 cm vs 2.36 cm, 2.08 cm, and 2.08 cm, respectively; P =.083, P =.008, and P =.038, respectively).
A high percentage (73%) of patients who received the sham intervention decided to cross over to active treatment at 1 year, and only 1 patient in this cross-over group experienced a device-related adverse event, but it resolved by 8 weeks. All other adverse events were mild to moderate in severity and resolved. Only 1 patient demonstrated a change in Modic type from type I to type II at the inferior and superior levels of L5 and S1, respectively, between 6 weeks and 6 months post-intervention.
Additional research using a longer follow-up period may be helpful to determine the long-term efficacy and safety of radiofrequency ablation of the basivertebral nerve in patients with chronic low back pain. In addition, the use of more objective measures for the assessment of chronic low back pain and functional improvement may help to determine how useful the procedure is in this patient population.
“Using a 10-point ODI improvement as a threshold, 75.6% of treatment arm patients as opposed to 55.3% of sham arm patients were characterized as responders,” concluded the study authors.
Fischgrund JS, Rhyne A, Franke J, et al. Intraosseous basivertebral nerve ablation for the treatment of chronic low back pain: a prospective randomized double-blind sham-controlled multi-center study [published online February 8, 2018]. Eur Spine J. doi: 10.1007/s00586-018-5496-1