Clinical correlation of a new and practical magnetic resonance grading system for cervical foraminal stenosis assessment

Background No systematic and quantitative system for evaluation of cervical neural foraminal stenosis (CNFS) has been reported. Purpose To evaluate whether the new magnetic resonance (MR) grading system for CNFS correlates with clinical manifestations and to propose a modified grading system more useful for clinical practice. Material and Methods We examined 356 patients who underwent MR imaging (MRI) of the cervical spine. The presence and grade of cervical foraminal stenosis at the maximal narrowing point were assessed using the new grading system suggested by Kim et al. (Kim system) and a modification of this grading system (modified Kim system) based on T2 axial images. Grade 0: narrowest neural foramen > extraforaminal root; Grade 1: ≤ extraforaminal root; Grade 2: <50% of extraforaminal root. Modified Kim system: Grade 0: >80%, Grade 1: <80% but >50%, Grade 2 as for the Kim system. Results were correlated with clinical manifestations and neurologic physical examination findings (positive neurologic manifestation [PNM]). Results Analysis of correlation coefficients (Rs) showed moderate correlation between grades and clinical manifestations using the Kim system (0.484-0.562) and moderate to high correlation between grades and PNMs using the modified Kim system (0.517-0.782). Conclusion The Kim system showed moderate correlation clinical findings, while the modified Kim system still showed moderate but slightly stronger correlation. In both systems, grade 0 could denote negative neurologic manifestations. Although a considerable number of grade 1 and 2 cases in both systems had PNM, fulfilling the criteria for grades 1 and 2 CNFS, it does not perfectly predict PNM.