Inter-rater reliability of MRI superior articular process angle measurement for use in the modified approach to cervical transforaminal epidural steroid injections

Abstract

BackgroundUpper extremity radicular pain is commonly treated with a cervical transforaminal epidural steroid injection (CTFESI). Recently, a new technique, the modified approach CTFESI, has been developed with a theoretical safety advantage to avoid the neurovascular structures. This approach requires an angle measurement of the superior articular process (SAP) on MRI. The inter-rater reliability of this angle measurement among practicing physicians is yet to be investigated. ObjectiveThe purpose of this study was to determine the inter-rater reliability of SAP angle measurements on MRI. MethodsThree raters independently measured the SAP angle on 50 cervical MRIs. A two-way, mixed effects, absolute agreement, single rater statistical model was used to determine the intraclass correlation coefficient (ICC) between all three raters, as well as between each pair of raters. ResultsInter-rater reliability among all raters showed good reliability with an ICC ​= ​0.837709 (95% CI 0.75–0.9, p ​< ​0.001). Similarly, good inter-rater reliability was found between each of the pairs of raters. ConclusionThis study demonstrates good inter-rater reliability of MRI SAP angle measurement among clinicians for use in the modified CTFESI approach.