Quantitative evaluation for cervical foraminal bony stenosis based on angled sagittal slices along a nerve root on computed tomography

Abstract

Cervical foraminal canal stenosis is a common disease, but any relationships between the measurement values of cervical foraminal canals and clinical symptoms have yet to be explored. We aim to determine a numerical cutoff point of cervical foraminal bony canal size that does not lead to radiculopathy so as to establish criteria for the surgical indication. We reconstructed angled sagittal slices along a nerve root on computed tomography (CT) on a workstation from pre-operative CT data and measured 1152 cervical foraminal canals (144 patients) from Cervical (C) 4/5 to C7/Thoracic (Th) 1. We evaluated the relationship between the size of foraminal canals and clinical manifestations. Receiver operating characteristic (ROC) analysis was used to calculate cutoff points of each foraminal canal size with positive neurologic manifestations. Of the 144 patients’ 1152 nerve roots, 286 nerve roots (24.8%) were diagnosed as radiculopathy by neurological examinations. The mean measured value of all foraminal canals on angled sagittal CT imagery was 3.39 ± 1.37 mm. The cutoff point of foraminal canal sizes without radiculopathy was 2.7 mm (sensitivity 0.680, specificity 0.591) overall. A cutoff point ascertained by quantitative evaluation of cervical foraminal canal size is useful for making diagnosis of cervical foraminal canal bony stenosis.