The vertebral laminae are paired flat bony plates connecting the pedicles to the spinous process, forming the posterior arch of the vertebral canal. The laminae fuse in the midline at the spinous process. The ligamentum flavum is attached to the anterior surface of each lamina, and the erector spinae muscles attach to the posterior surface. Laminae vary in thickness from 3-5 mm cervically to 6-10 mm lumbarly.
Laminectomy (removal of one or more laminae) is the primary decompressive procedure for spinal stenosis, removing the posterior arch to enlarge the spinal canal. Laminoplasty preserves one lamina hinge to reconstruct the posterior arch and avoid post-laminectomy kyphosis and instability, particularly in the cervical spine. Epidural injections and spinal anaesthesia pass through the interlaminar space between adjacent laminae. Ligamentum flavum hypertrophy from the laminar attachment is a major contributor to lumbar and cervical spinal stenosis.
Thickening of the laminae and attached ligamentum flavum with age produces posterior spinal canal narrowing that combines with anterior disc and facet joint hypertrophy to create central canal stenosis, producing neurogenic claudication managed by laminectomy or interlaminar decompression.
Multi-level cervical laminoplasty opens the posterior arch by hinging each lamina on one side while detaching the other, expanding the spinal canal without fusion, preserving motion and avoiding the kyphosis risk of laminectomy alone in patients with preserved cervical lordosis.
