This procedure removes part of a lamina of the vertebral arch in order to decompress the corresponding spinal cord and/or spinal nerve root.

This was originally performed as a hemilaminectomy, consisting in the removal of either the left or right half of the lamina, but is now more commonly carried out as the removal of a portion of both sides of the lamina (while retaining the rest to preserve vertebral stability as much as possible). Laminotomy is also often accompanied by facetectomy.

Lumbar unilateral laminotomy with crossover,

Bilateral laminotomy.

Spinous process osteotomy.

Various technical modifications of lumbar laminectomy have been suggested to minimize the limitations of the procedure. These include bilateral laminotomy and unilateral laminotomy with bilateral decompression.

These modifications are intended to safeguard spinal stability by preserving the midline supporting structures, such as spinous processes and interspinous ligaments, while decompressing the central and lateral areas of the surgical level.

see split laminotomy