SPECT-CT as a Predictor of Pain Generators in Patients Undergoing Intra-Articular Injections for Chronic Neck and Back Pain

Abstract

The ability to accurately predict pain generators for chronic neck and back pain remains elusive. We evaluated whether injections targeted at foci with uptake on single-photon emission computerized tomography-computed tomography (SPECT-CT) were associated with improved outcomes in patients with chronic neck and back pain. A retrospective review was completed on patients undergoing SPECT-CT for chronic neck and back pain between 2016 and 2020 at a tertiary academic center. Patients' records were reviewed for demographic, clinical, imaging, and outcomes data. Only those patients who had facet injections after SPECT-CT were included in this evaluation. Patients undergoing injections targeted at foci of abnormal radiotracer uptake were compared with patients without uptake concerning immediate positive response, visual analog scale, and the need for additional injection or surgery at the target level. A total of 2849 patients were evaluated with a SPECT-CT for chronic neck and back pain. Of those, 340 (11.9%) patients received facet joint injections after SPECT-CT. A propensity score regression analysis adjusted for age, gender, body mass index, hypertension, multiple target injections, and injection location showed uptake targeted injections not being associated with an improved immediate positive response (odds ratio: 0.64; 95% confidence interval: 0.34-1.21; P= 0.172). In patients with a failed facet injection preceding SPECT-CT, adding SPECT-CT to guide facet injections was associated with a decrease in visual analog scale pain scores 2 weeks after injection (P= 0.018), particularly when changes were made to the facets being targeted (P= 0.010). This study suggests that there is benefit with SPECT-CT specially to guide facet injections after failed prior facet injections.