The positive prediction of single photon emission computed tomography/ computed tomography (SPECT/CT) in the outcome of intervention for cervical facet pain.

BACKGROUND CONTEXT: Previous studies have reported that magnetic resonance imaging (MRI) and computed tomography (CT) do not predict response to facet blocks. However, single photon emission computed tomography (SPECT) uptake within facet joints has been shown to correlate with pain relief after intervention in the lumbar spine. There is minimal data regarding the predictive value of single photon emission computed tomography/computed tomography (SPECT/CT) for neck pain. PURPOSE: The aim of this study was to evaluate the utility of SPECT/CT in patients with axial neck pain for the identification of specific facet joints that would benefit from diagnostic and therapeutic facet joint steroid injections and/or medial branch block/RFA treatments. STUDY DESIGN: A retrospective cohort study. PATIENT SAMPLE: One hundred seventy-nine patients at a single institution pain center with neck pain and a SPECT/CT scan between 2009 and 2015. One hundred twelve patients had no prior intervention at the level of interest and met inclusion criteria. OUTCOME MEASURES: Pain reduction at 50% and 80% thresholds within 24 hours of facet intervention. Concordance of facet intervention with the focus of maximal uptake on SPECT/CT scan. METHODS: All patients were referred to our institution's Center for Pain Medicine and were treated with facet interventions. The site of facet intervention was determined by pain center providers based on their clinical examination and interpretation of images. Groups were formed based on whether the facet intervention included the level of maximal uptake on SPECT/CT scan. A positive response to intervention was defined at both 50% and 80% thresholds for reduction in pain within 24 hours of facet injection with steroid and local anesthetic or medial branch block with local anesthetic only. These were the facet interventions used for our data collection. A Chi-square statistic was used to analyze categorical data and a Student's t-test was used to analyze non-categorical data. SPSS (IBM Corp. IBM SPSS Version 24.0) was used for all analyses. RESULTS: Of our 112 patients, Group 1 consisted of 89 with an intervention occurring at the level with increased uptake on SPECT/CT. Group 2 consisted of 23 patients with an intervention at a level without uptake on SPECT/CT. Demographic data did not significantly differ between cohorts. A Chi-square test of independence demonstrated that intervention at a level concordant with SPECT/CT was significantly correlated with self-reported pain relief thresholds of both 50% and 80% (p=.0002). CONCLUSIONS: Facet interventions based on SPECT/CT scan uptake were more successful in pain reduction than those which were not. This suggests a role for SPECT/CT in diagnosing therapeutic targets for neck pain.