INTRODUCTION: Coexisted cases of cervical spondylotic myelopathy (CSM) and lumbar spinal stenosis (LSS) were sometimes found. However, there have been few reports regarding cervical spinal stenosis in patients with LSS. The purpose of this study is to evaluate the developmental narrow spinal canal in patients with LSS.
METHODS: Two hundred thirty seven patients with LSS (117 males and 120 females, from 35 to 85 years old, an average of 68.7) and 100 cases of cervical sprain as control (50 males and 50 females, from 20 to 85 years old, an average of 41.6) were studied. LSS was diagnosed by characteristic symptoms, physical findings and MRI. Plain lateral cervical radiographs were taken in all cases. A‐P diameter of cervical spinal canal and vertebral body from C3 to C6 level were measured, and then a Torg‐Pavlov ratio (TPR, canal/body ratio) was calculated. Each measurement was performed three times. Developmental cervical spinal stenosis was recognized by TPR of less than 0.8.
RESULTS: Twenty one patients had CSM in this study. There were 114 patients (80 males and 34 females) that showed a TPR of less than 0.8 in 237 patients. Especially this rate was significantly high in male patients (68.4%). In the group of LSS the mean TPR value was 0.76 in males and was 0.85 in females, both significantly lower than those of the control group (0.88 in males and 0.97 in females, both p<0.01).
DISCUSSION: This study demonstrated that about 50% of patients with LSS had cervical spinal stenosis. The mean TPR in the group of LSS was also significantly lower than those of the control group. Developmental narrow spinal canal including the cervical spine might be an important factor in the pathogenesis of LSS.