C1 Cervical Stenosis Causing Chronic Neck Pain and Ataxia: The Importance of Physical Examination and Radiographic Imaging

A 55-yr-old man presented to an interventional pain management clinic for chronic right-sided neck and shoulder pain and “left foot dragging” that started 1 yr ago without inciting trauma. He described the pain as an “aching” pain with associated tingling in the right arm, made worse with use of the affected side. The patient otherwise denied radicular symptoms, bowel or bladder dysfunction, or saddle anesthesia. Physical examination was notable for tenderness to palpation of right-sided cervical paraspinal and trapezius musculature, and clonus of the left leg. The patient also demonstrated an ataxic, scissoring gait pattern and a positive Romberg sign.

Before this office visit, the patient was evaluated by a neurologist and was scheduled for a cervical-spine MRI in the near future. In the meantime, a cervical-spine x-ray was obtained, which demonstrated anterior displacement of the posterior C1 arch relative to the spinolaminar line suggestive of severe cervical spinal canal stenosis (Figs. 1, 2). The follow-up cervical-spine MRI later supported these findings with additional evidence for myelomalacia. The patient was subsequently referred to neurosurgery and underwent a C1 laminectomy with occiput-to-C4 fusion. He was admitted for 1 mo to an inpatient acute rehabilitation floor and discharged without complication, with improvements in gait on outpatient follow-up.

FIGURE 1: Lateral cervical spine x-ray demonstrating marked widening of the anterior atlantodental interval, resulting in anterior displacement of the posterior C1 arch relative to the spinolaminar line.

FIGURE 2: Sagittal T2 MRI imaging redemonstrating enlargement of the atlantodental interval resulting in severe spinal canal stenosis with severe thinning and T2 hyperintensity of the spinal cord at the level of C1 suggestive of myelomalacia.

Cervical spinal stenosis at the C1 level is rare, given that the diameter of the cervical canal is typically largest at this level.¹ While MRI can be used to diagnose cervical stenosis, imaging may be delayed because of scheduling and insurance limitations. Oshima et al.² suggest the C3/2 spinolaminar test, as a simple, yet effective screening tool to detect patients with decreased space available for the cord at the C1 level on x-ray imaging. They demonstrated a 100% sensitivity and 97% in detection of patients with decreased C1 space available for the cord compared with C2, with 25% of these patients later demonstrating spinal cord compression on MRI.² Thus, a comprehensive history and physical examination coupled with this screening tool can help correctly diagnose C1 cervical stenosis and prevent further injury.