Medial Branch Block Guided by SPECT-CT for Patients with Chronic Cervical Pain

Introduction: Chronic neck pain remains one of the most common causes of disability and medical office visits. Our ability to accurately identify painful generators remains limited with renewed attention being devoted to functional imaging modalities such as SPECT-CT. We aimed to evaluate whether SPECT-CT can accurately predict facetogenic painful generators in patients undergoing medial branch nerve blocks (MBB).

Methods: A retrospective cohort review was completed on patients having a cervical MBB between 2010 and 2022 at a tertiary academic center. Patients undergoing MBB after SPECT-CT were eligible for final analysis. Records were reviewed for demographic, clinical, imaging and outcome data. Injections at foci of positive uptake were compared with injections at foci without update and compared in terms of immediate positive response, and visual analog score – VAS.

Results: A total of 45 patients underwent MBB after SPECT-CT with a median immediate change in VAS of 3 (IQR=3). Age (regression coefficient 0.05 +/- 0.03, p=0.083) , male gender (regression coefficient -0.76 +/- 0.60, p=0.218), time to MBB (regression coefficient 0.001+/- 0.003, p=0.716) and injections targeting areas of foci uptake (regression coefficient 0.61 +/- 0.82, p=0.460) were not associated with improved patient outcomes. Similarly, there was no difference in patient-reported outcomes on univariate linear regression when comparing injections targeting foci of radiotracer uptake to injections at foci without uptake (regression coefficient 0.81 +/- 0.81, p=0.324).

Conclusion : This study suggests limited benefit with SPECT-CT to guide MBB for chronic neck pain, with larger placebo-controlled randomized clinical trials being needed to clearly ascertain if there might be benefit and to guide patient selection.