Inter- and Intraobserver Agreement of Morphological Grading for Central Lumbar Spinal Stenosis on Magnetic Resonance Imaging.

Study Design Validation study of a morphological grading system for central lumbar spinal stenosis. Objective To evaluate and validate the inter- and intraobserver agreement of a morphological grading system for central lumbar spinal stenosis on magnetic resonance imaging between neurosurgeons and radiologists. Methods Two neurosurgeons and two radiologists independently assessed the morphological grading of lumbar spinal stenosis on pretreatment magnetic resonance imaging of 84 patients. Inter- and intrarater agreements were calculated by comparing the observers' evaluations level to level on the grading method. The results of both clinicians were compared with the assessment of both radiologists. Results On axial magnetic resonance images, 189 lumbar disk levels were evaluated for the grade of stenosis. The interobserver agreement between the clinicians was substantial. The interobserver agreement between clinician 1 and both radiologists was substantial, and it was moderate between clinician 2 and both radiologists. The clinicians' intraobserver agreement was almost perfect, and the radiologists' intraobserver agreement was substantial. Conclusions The interobserver agreement of this morphological grading for lumbar spinal stenosis was high between both the clinicians and radiologists, whereas the intraobserver agreement was almost perfect. Experienced clinicians may safely evaluate lumbar magnetic resonance images using this morphological grading for central lumbar spinal stenosis.