Correlation of Foraminal Area and Response to Cervical Nerve Root Injections

INTRODUCTION Patients with age-related degenerative changes in the cervical spine leading to cervical spondylosis may be symptomatic or asymptomatic. Older patients with radicular pain tend to have a better response to epidural steroid injections, but it is often difficult to predict which patients will have a positive response to selective nerve root block (SNRB). We analyzed whether the cervical neuroforaminal area measured on MRI predicts immediate therapeutic responses to SNRB in patients who have cervical radiculopathy. METHODS We retrospectively reviewed all patients who had cervical SNRBs treated at a single tertiary referral center. We recorded patient demographics, the neuroforaminal area of the symptomatic and contralateral sides, Visual Analog Scale (VAS) score pre- and post-injection, history of previous cervical surgery, comorbidities, and history of tobacco use. RESULTS Sixty-four patients with symptoms of cervical radiculopathy treated with neuroforaminal nerve root injections had appropriate imaging and VAS scores recorded. The average foraminal area of the symptomatic side before treatment was significantly smaller than the contralateral asymptomatic neuroforamen (p<0.0001). Those patients with the smallest neuroforamen had a positive response to SNRB. Diabetes and tobacco use did not influence patient response to treatment. CONCLUSIONS Measurement of neuroforaminal areas on MRI may represent a useful pre-procedural technique to predict which patients with symptoms of cervical radiculopathy secondary to foraminal stenosis are likely to respond to selective nerve root injections. The predictive ability appears to be limited to those patients with severe stenosis and was less useful in those patients with moderate or mild stenosis.