Selective diagnostic nerve root block for the evaluation of radicular pain in the multilevel degenerated cervical spine

In patients with radiculopathy due to degenerative disease in the cervical spine, surgical outcome is still presenting with moderate results. The preoperative investigations consist of clinical investigation, careful history and most often magnetic resonance imaging (MRI) of the cervical spine. When MRI shows multilevel degeneration, different strategies are used for indicating which nerve root/roots are affected. Some authors use selective diagnostic nerve root blocks (SNRB) for segregating pain mediating nerve roots from non-pain mediators in such patients. The aim of the present study is to assess the ability of transforaminal SNRB to correlate clinical symptoms with MRI findings in patients with cervical radiculopathy and a two-level MRI degeneration, on the same side as the radicular pain. Thirty consecutive patients with cervical radiculopathy and two levels MRI pathology on the same side as the radicular pain were studied with SNRBs at both levels. All patients underwent clinical investigation and neck and arm pain assessment with visual analogue scales (VAS) before and after the blocks. The results from the SNRBs were compared to the clinical findings from neurological investigation as well as the MRI pathology and treatment results. Correlation between SNRB results and the level with most severe degree of MRI degeneration were 60% and correlation between SNRB results and levels decided by neurological deficits/dermatome radicular pain distribution were 28%. Twenty-two of the 30 patients underwent treatment guided by the SNRB results and 18 reported good/excellent outcome results. We conclude that the degree of MRI pathology, neurological investigation and the pain distribution in the arm are not reliable parameters enough when deciding the affected nerve root/roots in patients with cervical radiculopathy and a two-level degenerative disease in the cervical spine. SNRB might be a helpful tool together with clinical findings/history and MRI of the cervical spine when performing preoperative investigations in patients with two or more level of degeneration presenting with radicular pain that can be attributed to the degenerative findings.