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

Abstract

Background: Medial branch blocks are used to select patients for cervical facet joint radiofrequency neurotomy (CRFN). Blocks are typically performed under fluoroscopic guidance (FLB). The validity of ultrasound guided blocks (USB) is not well established. No prior research has compared cervical USB versus FLB validity using CRFN outcome as the criterion standard.

Objective: To evaluate cervical USB versus FLB validity using CRFN outcome as the criterion standard.

Methods: Demographic and outcome data were extracted from the EMRs of two affiliated MSK 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 to a matched FLB patient from the RFN outcome database of the same clinics. Matching variables included patient age, sex, pain duration, diagnostics/prognostic block paradigm and CRFN number. Each patient completed a NRS pain score and Pain Disability Quality-of-Life Questionnaire (PDQQ) just before and 3-months post-CRFN. At repeat CRFN, patients provided a retrospective estimate of the duration and average magnitude (%) of relief following 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-S scores demonstrated comparable (p > 0.05) absolute improvements, proportion of patients achieving ≥50% improvement, and attainment of MCID. 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.