Selective diagnostic cervical nerve root block -: correlation with clinical symptoms and MRI-pathology

Background. The aim of this study is to describe the method of a cervical selective diagnostic nerve root block (SNRB) technique and assess its ability to correlate clinical symptoms with MRI findings in patients with cervical radicular pain and a single level degenerative disease. Methods. Twenty consecutive patients with cervical radiculopathy and correlating single level MRI pathology were studied. All patients underwent clinical investigation and neck and arm pain measurement with visual analog scales (VAS). The last 10 consecutive patients also underwent provocation with active neck motion when arm and neck pain were measured. They all underwent SNRB and 1 ml local-anesthesia (Mepivacaine 10 mg/ml) was injected, with the aid of fluoroscopy, close to the nerve-root. The VAS estimation and clinical investigation including provocation were repeated 30 minutes after the block. Criteria for a positive block response are a significant subjective pain reduction and at least 50% VAS pain reduction in the arm. Findings. For the whole group mean VAS arm pain reductions were 86% and mean VAS neck pain reductions were 65%. When the results from the provocation were added all patients had a positive block. Eighteen were operated on by an anterior procedure and all 18 were free from radicular pain at follow up. Interpretation. The block procedure seems relevant for revealing a relationship between radiological pathology and clinical symptoms and signs.