Uncinate Process Area as a New Sensitive Morphological Parameter to Predict Cervical Neural Foraminal Stenosis

Abstract

Background: Hypertrophy of the uncovertebral joint has been considered as a major cause of cervical neural foraminal stenosis (CNFS). The cross-sectional area of the uncinate process is a key morphologic parameter in the identification of uncovertebral joint hypertrophy. To evaluate the connection between CNFS and the uncinate process, we devised a new morphological parameter, the uncinate process area (UPA). Objective: We hypothesized that the UPA is an important morphologic parameter in the diagnosis of CNFS. Study Design: Retrospective observational study. Setting: The single center study in Incheon, Republic of Korea. Methods: UPA data were collected from 146 patients with CNFS and 197 control subjects who underwent neck computed tomography (CT) as part of a routine medical examination. Neck CT images were obtained from all subjects. The whole cross-sectional area of the bone margin of the uncinate process was measured at the C5-6 intervertebral disc level on CT scans using a picture archiving and communications system. Results: The average UPA was 15.52 mm(2) in the control group and 29.97 mm(2) in the CNFS group. The CNFS group displayed significantly greater UPA levels (P< 0.001). Regarding the validity of the UPA as a predictor of CNFS, the receiver operating characteristic curve analysis revealed an optimal cut-off point for the UPA of 21.15 mm(2), with 91.8% sensitivity, 93.4% specificity, and an area under the curve of 0.972 (95% CI,0.956-0.989) in the CNFS group. Limitations: Anatomically, the UP is located on the superior lateral surfaces of the C3-7 cervical vertebral bodies. However, we focused on the C5-6 uncovertebral joint level, because many previous studies revealed C6 UP has the greatest height among UP and C5-6 uncovertebral joint hypertrophy is a primary cause of CNFS. Conclusions: The newly devised UPA is a sensitive parameter for assessing CNFS. A hypertrophied UPA is associated with an increased risk of CNFS. We think that this result will be helpful for diagnostic radiology in evaluating patients with CNFS.