For a study, the researchers aimed to provide anatomic descriptions of the normal lumbar sublaminar ridge in the lateral recess and its potential to impact the exiting nerve root there, with implications to the surgical technique in lumbar spinal stenosis. The setting of degenerative lumbar stenosis structure could hypertrophy and impinge the nerve root within the lateral recess even after excision of the corresponding ligament flavum. About 15 lumbar vertebrae, not degenerated, were resected from 3 fixed adult human cadavers and then were transacted through the pedicles, leaving the posterior column and neural elements intact and articulated. The shape of the sublaminar ridge in the lateral recess and its relationship to the exiting nerve root was carefully examined. The exiting nerve root consistently crossed the sublaminar ridge immediately inferior to the mid-pedicle, lateral to the subarticular gutter, and on the medial aspect of the true intervertebral foramen. A hypertrophic ridge can compress the exiting root by elevating the nerve root superiorly against the bony underside of the pedicle or displacing it anteriorly against the disc or vertebral body. The sublaminar ridge in the lateral recess was thought to contribute to degenerative lumbar stenosis. A comprehensive appreciation of this anatomy facilitated through lateral recess decompression.
