Assessment of Prevalence of Cervical Facet Joint Pain with Diagnostic Cervical Medial Branch Blocks: Analysis Based on Chronic Pain Model.

BACKGROUND: Research into cervical spinal pain syndromes has indicated that the cervical facet joints can be a potent source of neck pain, headache, and referred pain into the upper extremities. There have been multiple diagnostic accuracy studies, most commonly utilizing diagnostic facet joint nerve blocks and an acute pain model, as Bogduk has proposed. Subsequently, Manchikanti has focused on the importance of the chronic pain model and longer lasting relief with diagnostic blocks.

OBJECTIVE: To assess diagnostic accuracy of cervical facet joint nerve blocks with controlled comparative local anesthetic blocks, with updated assessment of prevalence, false-positive rate, and a description of philosophical paradigm shift from acute to chronic pain model, with concordant pain relief.

STUDY DESIGN: This diagnostic accuracy study was performed with retrospective assessment of data to assess prevalence and false-positive rates.

SETTING: The study was performed in a non-university-based, multidisciplinary, interventional pain management, private practice in the United States.

METHODS: Cervical medial branch blocks were performed utilizing lidocaine 1% followed by bupivacaine 0.25% when appropriate response was obtained in an operating room under fluoroscopic guidance with 0.5 mL of lidocaine or bupivacaine from C3-C6 medial branches (levels blocked on joints involved). If a patient failed to respond to lidocaine with appropriate >= 80% pain relief, that patient was considered as negative for facet joint pain. If the response was positive with lidocaine block, a bupivacaine block was performed.

RESULTS: The chronic cervical facet joint pain was diagnosed with cervical facet joint nerve blocks at a prevalence of 49.3% (95% CI, 43.6%, 55.0%) and with a false-positive rate of 25.6% (95% CI, 19.5%, 32.8%). This study also showed a single block prevalence rate of 66.3% (95% CI, 71.7%, 60.9%). Assessment of the duration of relief with each block showed greater than 80% for 6 days with lidocaine block and total relief of >= 50% of 31 days. In contrast, with bupivacaine, average duration of pain relief of >= 80% was 12 days with a total relief of >= 50% lasting for 55 days.

CONCLUSION: Based on this investigation, utilizing a chronic pain model, there was significant difference in the relief patterns. This assessment showed prevalence and false-positive rates of 49.3% and 25.6% in chronic neck pain. Duration of relief >= 80% pain relief was 6 days with lidocaine and 12 days with bupivacaine, with total relief of >= 50% of 31 days with 55 days respectively.