Evaluating the effectiveness of 7-min basivertebral nerve ablation in treating vertebrogenic low back pain.

Background: Basivertebral nerve radiofrequency ablations (BVNRFA) is an established treatment for chronic vertebrogenic low back pain. However, published studies have exclusively evaluated the effectiveness of 15-min ablations for BVNRFA. Recently, industry has recommended performing 7-min ablations but there is no literature demonstrating this as an effective procedure. Objective: The purpose of this study was to evaluate 7-min BVNRFA outcomes of pain and function. Methods: Retrospective review of consecutive patients with chronic (>6 months) axial midline low back pain with a reported pain score ≥4 that had failed conservative treatment with corroborating Modic type I or Modic type II changes on MRI who underwent exclusively 7-min BVNRFA was conducted at a multidisciplinary spine center. Visual analog pain scores (VAS) were collected at baseline, 1-, 3-, 6-, and 12-month post-procedure. Consistent with prior literature, success was defined two ways: achieving a ≥50 % in VAS pain reduction at post-procedure visits compared to baseline scores and achieving a reduction of VAS greater than the minimally clinical important difference of 2. Wilcoxon signed-rank test was used to compare post-procedure scores with baseline scores. Percent of patients with a successful treatment was calculated at each follow-up time period. Results: A total of 86 patients underwent BVNRFA during the study period and 75 met inclusion criteria. VAS scores significantly improved between baseline (7.1 ± 1.9) and 1-month (3.9 ± 3.0, p < 0.001), 3-months (3.4 ± 3.0, p < 0.001), 6-months (4.4 ± 2.6; p < 0.001) and 12-months post-procedure scores (3.7 ± 2.6; p < 0.001). The percentage of patients with a successful treatment of ≥50 % in VAS pain reduction was 50.7 % (95 % CI 38.8 %, 26.7 %) at 1-month, 56.9 % (95 % CI 44.9 %, 69.0 %) at 3-months, 42.9 % (95 % CI 29.0 %, 56.7 %) at 6-months and 50.0 % (95 % CI 23.1 %, 67.9 %) at 12-months. The percentage of patients with a successful treatment of ≥2 in VAS pain reduction was 67.2 % (95 % CI: 55.9 %, 78.4 %) at 1-month, 67.7 % (95 % CI: 56.3 %, 79.1 %) at 3-months, 65.3 % (95 % CI: 52.0 %, 78.6 %) at 6-months and 70.0 %, (95 % CI: 52.1 %, 90.8 %) at 12-months. Conclusions: Although our study demonstrated that patients treated with BVNRFA with a 7-min ablation reported significant improvement in pain, the proportion of patients with a successful reduction of pain is likely lower than data published for 15-min ablations. Future controlled trials comparing outcomes and lesion sizes of 7- and 15-min BVNA are needed.