Laminectomy

Laminectomy is the resection of the lamina of a vertebral body. By removing the lamina the spinal canal is decompressed reducing pressure on the spinal cord / cauda equina.

Terminology

When only one of the lamina is resected the terms hemilaminectomy or unilateral hemilaminectomy can be used depending on regional preferences.  

Indications

• symptomatic spinal stenosis ¹
• symptomatic compressive myelopathy ⁵

Procedure

Laminectomies are most commonly performed in the lumbar spine ^ref. They can be an open or minimally invasive procedure. When minimally invasive, unilateral laminectomy for bilateral decompression (ULBD) is the predominant technique ³. Laminectomies are often accompanied by facetectomy, foraminotomy and/or instrumented spinal fusion ². 

Open approach

• stripping of the paraspinal muscles from the spinous process
• removal of the spinous processes
• removal of the lamina (either piecemeal or en bloc) and identify the ligamentum flavum origin
• resection of the ligamentum flavum ^1,5

Minimally invasive approach

• introduction of a tubular retractor over K-wire onto a facet joint with removal of attached soft tissues
• use of endoscope and operative microscope
• ipsilateral laminectomy and medial facetectomy performed using a high-speed drill with removal of ipsilateral ligamentum flavum
• "wanding" of the tubular retractor allows for undercutting of the spinous process and contralateral laminectomy then ligamentum flavum resection ^3,4,6

Complications

• immediate post-operative complications are similar between the two groups ³
  • intraoperative dural injury
  • wound infection
  • CSF leak
• spinal instability may be more common in open vs minimally invasive approaches ³

Outcomes

• open laminectomy has a success rate for treating lumbar spinal stenosis of ~65% (range 62-70%) ³