An analysis on reliability of the lee and wildermuth magnetic resonance imaging grading systems for lumbar neural foraminal stenosis

Abstract

Background: There is no uniformly accepted magnetic resonance imaging (MRI) grading system existing for lumbar neural foraminal stenosis (LNFS). Radiologists' reporting on neural foramen stenosis is qualitative and subjective. There are two grading systems proposed by Lee and Wildermuth. Aims : To evaluate the reliability between Lee and Wildermuth grading systems for lumbar foraminal stenosis and analyze their relative merits. Settings and Design: A retrospective, cross-sectional analytical study. Materials and Methods: A total of 136 consecutive patients (63 males and 73 females; mean age 56.3 years) aged above 40 years with low backache found to have degenerative disc disease after MRI of the lumbar spine at a tertiary care hospital in South India from July to September 2015. Two general radiologists reviewed the MRI studies independently for the presence and grading of stenosis at L3/4, L4/5, and L5/S1 neural foramina. They graded neural foramen stenosis with Lee and Wildermuth systems at different occasions and were blinded to all previous grading. Statistical Analysis Used: Interobserver agreement between the radiologists and intraobserver agreement by one radiologist for one system each were analyzed using kappa statistics. Results: Wildermuth system of LNFS showed substantially higher inter- and intra-observer agreements than Lee system. Overall inter-rater and intra-rater agreements (k) for Wildermuth system are 0.700 and 0.762, respectively, and that of Lee system are 0.394 and 0.702. Conclusions: Wildermuth system is more reliable than Lee system for general radiologists. It also accounts slight neural foramen stenosis without perineural fat obliteration unlike in Lee system.