Can ultrasound-guided medial branch blocks be used to select patients for cervical facet joint radiofrequency neurotomy? A matched retrospective cohort validation study

Abstract

Abstract Background Medial branch blocks are used to select patients for cervical facet joint radiofrequency neurotomy (CRFN). Blocks are typically performed under fluoroscopic guidance (ie, fluoroscopy-guided blocks [FLBs]). The validity of ultrasound-guided blocks (USBs) is not well established. No prior research has compared cervical USB validity and FLB validity with CRFN outcome used as the criterion standard. Objective To evaluate cervical USB versus FLB validity with CRFN outcome used as the criterion standard. Methods Demographic and outcome data were extracted from the electronic medical records of 2 affiliated musculoskeletal pain management clinics for all patients between 2015 and 2023 inclusive who had cervical USB leading to CRFN. CRFN outcomes of each USB patient were compared with those of a matched FLB patient from the radiofrequency neurotomy (RFN) outcome database of the same clinics. Matching variables included patient age, sex, pain duration, diagnostic/prognostic block paradigm, and CRFN number. Each patient completed a numeric rating scale (NRS) pain score and Pain Disability Quality-of-Life Questionnaire (PDQQ) just before and 3 months after CRFN. At repeat CRFN, patients provided a retrospective estimate of the duration and average magnitude (percentage) of relief after the CRFN. Results USB and FLB groups were comprised of 27 patients (58 RFNs) and 38 patients (58 RFNs), respectively. Post-RFN NRS pain severity and PDQQ-Spine scores demonstrated comparable (P > .05) absolute improvements, proportion of patients achieving ≥50% improvement, and attainment of the minimum clinically important difference. Retrospective estimates of pain relief magnitude and duration were also comparable. Conclusions This study finds cervical USB and FLB to be comparably valid as defined by their ability to predict CRFN outcome. Within the limitations of operator competence, USB can be used to select patients for CRFN.