What is the optimal block selection paradigm for predicting a successful treatment outcome following sacral lateral branch radiofrequency neurotomy? A real-world cohort study

Abstract

Background

Outcomes following sacral lateral branch radiofrequency neurotomy (SLBRFN) likely depend on patient selection criteria; however, commonly used criteria vary considerably. Refinement of selection criteria for SLBRFN may improve treatment outcomes. This study investigated common prognostic block-based selection criteria and treatment success following SLBRFN.

Methods

In this retrospective cohort study, consecutive patients from two Canadian musculoskeletal pain management clinics who underwent SLBRFN over a 6-year period (2016–2022) were identified by electronic medical record. Patients were categorized according to several prognostic block paradigms based on number of blocks (single vs. dual), block type (lateral branch block [LBB] vs. intra-articular block [IAB]), and subsequent percentage of pain relief. Six block criteria were established: 1 = LBB/LBB≥80 %; 2 = IAB/LBB≥80 %; 3 = LBB/LBB 50–79 %; 4 = IAB/LBB 50–79 %; 5 = LBB≥80 %; 6 = LBB 50–79 %. Treatment success was assessed at three months post-SLBRFN using two criteria: (1) the primary study outcome of ≥50 % numerical rating scale (NRS) pain reduction and (2) a secondary outcome of Pain Disability Quality-of-Life Questionnaire (PDQQ) score improvement by the minimal clinically important difference (MCID). Logistic regression analyses evaluated the association between block criteria and treatment success following SLBRFN.

Results

281 consecutive patients (75.1 % female, 61.8 ± 14.2 years of age, BMI 29.4 ± 6.6 kg/m²) were included. Cohort success rates for pain and functional improvement were 43.4 % (95 % CI: 37.8–49.3) and 46.6 % (95 % CI: 40.9–52.5), respectively. After adjusting for demographics and cannula type/SLBRFN technique, none of the odds ratios for the six prognostic block paradigms showed statistical significance.

Conclusion

Nearly 50 % of patients who underwent SLBRFN reported clinically significant improvement in pain and disability at three months post-procedure, regardless of prognostic block selection criteria. These results suggest that multiple block strategies may determine eligibility for SLBRFN.