Correlation between pyramidal signs and the severity of cervical myelopathy

A retrospective study was performed to determine the sensitivities of the pyramidal signs in patients with cervical myelopathy, focusing on those with increased signal intensity (ISI) in T2-weighted magnetic resonance imaging (MRI). The relationship between prevalence of the pyramidal signs and the severity of myelopathy was investigated. We reviewed the records of 275 patients with cervical myelopathy who underwent surgery. Of these, 143 patients were excluded from this study due to comorbidities that might complicate neurological findings. The MR images of the remaining 132 patients were evaluated in a blinded fashion. The neurological findings of 120 patients with ISI (90 men and 30 women; mean age 61 years) were reviewed for hyperreflexia (patellar tendon reflex), ankle clonus, Hoffmann reflex, and Babinski sign. To assess the severity of myelopathy, the motor function scores of the upper and lower extremities for cervical myelopathy set by the Japanese Orthopaedic Association (m-JOA score) were used. The most prevalent signs were hyperreflexia (94%), Hoffmann reflex (81%), Babinski sign (53%), and ankle clonus (35%). Babinski sign (P < 0.001), ankle clonus, and Hoffmann reflex showed significant association with the lower m-JOA score. Conversely, no association was found with the upper m-JOA score. In patients with cervical myelopathy, hyperreflexia showed the highest sensitivity followed by Hoffmann reflex, Babinski sign, and ankle clonus. The prevalence of the pyramidal signs correlated with increasing severity of myelopathy. Considering their low sensitivity in patients with mild disability, the pyramidal signs may have limited utility in early diagnosis of cervical myelopathy.