Lumbar spinal stenosis occurs as a result of wear and tear in the lower back over time. The resulting sciatica and leg pain, as well as possible numbness and weakness, may be alleviated by a surgery called a lumbar laminectomy.
To help you better understand how this surgery works, here is a step-by-step visual walk through of how a laminectomy addresses the anatomical problems caused by spinal stenosis:
The following images illustrate how sciatica pain can be caused by lumbar spinal stenosis, and how lumbar laminectomy surgery may relieve these symptoms.
The disease process
Degenerative changes in the lower spinal column may lead to an enlargement of the facet joints in the back of the spine.
Enlarged facet joints can pressure the nerves exiting the spine.
This image shows a close-up of the enlarged facet joint behind the spine. The facet joint is enlarged and is putting pressure on the nerves as they exit the spine.
The role of the lamina
The image below shows an individual vertebra, with the lamina highlighted in purple.
Each verterbra has two small flat bones, called lamina (shown here in purple) acting as a protective covering for the nerves in the back of the spine.
Specifically, in the lower back the lamina protect the cauda equina, nerve roots that branch off the spinal cord and extend throughout the lower spine. A lumbar laminectomy surgery removes all or part of the lamina to give the affected nerve roots more space to heal.
Two lamina stem off of each vertebra to protect the nerve roots.
How the surgery is done
Your surgeon will approach your spine through a 2- to 5-inch incision in the midline of your lower back.
Your back muscles, shown here in purple and called the erector spinae, will be dissected from the lamina.
Your surgeon will then remove the lamina, or a portion of the lamina, and expose the nerve roots (shown above in white).
Your surgeon may trim or undercut the facet joints to give the nerve roots more room. Once a sufficient amount of bone has been removed to reduce pressure on the nerves, the erector spinae will be sewn back together.
Decompression of the nerve root will usually relieve leg pain immediately after surgery, but numbness, tingling, and weakness could take up to a year to subside while the nerve heals.