Intraobserver and interobserver reliability of measures of cervical sagittal rotation

Abstract

BackgroundDiagnosis and treatment decisions of cervical instability are made, in part, based on the clinician’s assessment of sagittal rotation on flexion and extension radiographs. The objective of this study is to evaluate the intraobserver and interobserver reliability of three measurement techniques in assessing cervical sagittal rotation.MethodsFifty lateral radiographs of patients with single-level cervical degenerative disc were selected and measured on two separate occasions by three spine surgeons using three different measurement techniques. Cervical sagittal rotation was measured using three different techniques.ResultsIntraclass correlation coefficients were most consistent for Method 2 (ICC 0.93-0.96) followed by Method 1 (ICC 0.88-0.91) and Method 3 (ICC 0.81-0.87). Intraobserver agreement (% of repeated measures within 0.5° of the original measurement) ranged between 76% and 96% for all techniques, with Method 2 showing the best agreement (92%-96%). Paired comparisons between observers varied considerably with interobserver reliability correlation coefficients ranging from 0.54 to 0.89. Method 2 showed the highest interobserver reliability coefficient (0.82, range 0.73-0.88). Method 2 was also more reliable for the classification of “instability”. Intraobserver percent agreements ranged from 94 to 98% for Method 2 versus 84% to 90% for Method 1 and 78% to 86% for Method 3, while interobserver percent agreements ranged from 90% to 98% for Method 2 versus 86% to 94% for Method 1 and 74% to 84% for Method 3.ConclusionsMethod 2 (measuring the angle from the inferior endplate of the vertebra above the degenerative disc and the inferior endplate of the vertebra below the degenerative disc) showed the best intraobserver and interobserver reliability overall in assessing cervical sagittal rotation.Electronic supplementary materialThe online version of this article (doi:10.1186/1471-2474-15-332) contains supplementary material, which is available to authorized users.

Risk factors of dysphagia in patients with ossification of the anterior longitudinal ligament

“…Measurements of ROM of C2–C7 were performed as shown on the flexion and extension films with maximum effort of active motion. 14 PIA was defined as the angle between McGregor’s line and the line linking the center of the C1 anterior arch and the apex of the cervical sagittal curvature (Figure 1). 10,11…”