A laminotomy is a neurosurgical

Neurosurgery

Neurosurgery is the medical specialty concerned with the prevention, diagnosis, treatment, and rehabilitation of disorders which affect any portion of the nervous system including the brain, spine, spinal cord, peripheral nerves, and extra-cranial cerebrovascular system.-In the United States:In...

 procedure that removes part of a lamina of the vertebral arch

Lamina of the vertebral arch

The laminæ are two broad plates, extending dorsally and medially from the pedicles, fusing to complete the roof of the vertebral arch.Their upper borders and the lower parts of their anterior surfaces are rough for the attachment of the ligamenta flava....

 in order to decompress the corresponding spinal cord

Spinal cord

The spinal cord is a long, thin, tubular bundle of nervous tissue and support cells that extends from the brain . The brain and spinal cord together make up the central nervous system...

 and/or spinal nerve

Spinal nerve

The term spinal nerve generally refers to a mixed spinal nerve, which carries motor, sensory, and autonomic signals between the spinal cord and the body...

 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

Facetectomy

Facetectomy is a surgical procedure which involves decompression of a spinal nerve root. For example, it can be performed in severely resistant cases of cervical rhizalgia, where the cervical nerve roots within the intervertebral foramina are decompressed....

.