Laminectomy is a spine operation to remove the portion of the vertebral bone called the lamina. There are many variations of laminectomy. In the most minimal form small skin incisions are made, back muscles are pushed aside rather than cut, and the parts of the vertebra adjacent to the lamina are left intact. The traditional form of laminectomy (conventional laminectomy) excises much more than just the lamina; the entire posterior backbone is removed, along with overlying ligaments and muscles. The usual recovery period is very different depending on which type of laminectomy has been performed: days in the minimal procedure, and weeks to months with conventional open surgery.
As pictured, the lamina is a posterior arch of the vertebral bone lying between the spinous process, which juts out in the midline, and the more lateral pedicles and transverse processes of each vertebra. The pair of laminae, along with the spinous process, make up the posterior wall of the bony spinal canal. Although the literal meaning of laminectomy is excision of the lamina, the operation called conventional laminectomy, which is a standard spine procedure in neurosurgery and orthopedics, removes the lamina, spinous process and overlying connective tissues and ligaments, cutting through the muscles that overlie these structures. Minimal surgery laminectomy is a tissue preserving surgery that leaves the muscles intact, spares the spinal process and takes only one or both lamina. Laminotomy is removal of a mid-portion of one lamina and may be done either with a conventional open technique, or in a minimal fashion with the use of tubular retractors and endoscopes.
A lamina is rarely, if ever, removed because it itself is diseased. Instead, removal is done to: (1) break the continuity of the rigid ring of the spinal canal to allow the soft tissues within the canal to expand (decompression), or (2) as one step in changing the contour of the vertebral column, or (3) in order to allow the surgeon access to deeper tissues inside the spinal canal. Laminectomy is also the name of a spinal operation that conventionally includes the removal of one or both lamina as well as other posterior supporting structures of the vertebral column, including ligaments and additional bone.
Conventional open laminectomy often involves excision of the posterior spinal ligament, and some or all of the spinous process, and facet joint. Removal of these structures, in the open technique, requires cutting the many muscles of the back which attach to them. Laminectomy performed as a minimal spinal surgery procedure, however, allows the bellies of muscles to be pushed aside instead of transected, and generally involves less bone removal than the open procedure.