Abstract
We investigated preoperative percentage vital capacity (%VC) and forced vital capacity in 1 second (FEV1%) in 75 patients with cervical spondylotic myelopathy (CSM) and 41 patients with lumbar canal stenosis (LCS) as a control group. In 32 CSM patients, postoperative spirometry was performed. In CSM patients we also compared %VC between those with upper cervical lesions and the others. The upper cervical lesion group had high intramedullary signal intensity changes and the other group had no signal changes on T2-weighted MRI on the cranial side from the C4/5 level. In terms of FEV1%, there were no significant differences between the CSM group and the LCS group. However, the %VC in the CSM group was significantly lower than that in LCS. The %VC in the CSM group improved slightly after surgery. The %VC in the upper cervical lesion group was lower than that in the other CSM patients, but there were no significant differences between the two groups. The spinal segments of the main inspiratory muscles are present in the cervical spinal cord, and those of the main expiratory muscles are located in the thoracic spinal cord. We considered that the preoperative decrease of %VC in CSM was due to weakness of the respiratory muscles. Respiratory dysfunction is considered to be one form of impairment in CSM.
