Lumbar Laminectomy Surgery
Lumbar laminectomy is a surgery done in the lower spine to relieve the pressure off the neural structures. The surgery is commonly performed for a condition known as spinal canal stenosis when all other conservative management options have been tried. The results of lumbar laminectomy are excellent with a majority of patients experiencing significant relief of symptoms.
The spinal cord passes through the spinal canal created by the vertebral bodies. The spinal cord gives branches known as spinal nerves as it passes through the canal and ends around the second lumbar vertebra giving rise to a tuft of nerves known as cauda equina. The cauda equina continues down the spinal canal to supply the lower extremities and the pelvic organs.
The lamina forms the roof of the vertebrae and surrounds the spinal cord from the back and sides. Spinal stenosis is the narrowing of the spinal canal and compression of the spinal cord/dural sac/cauda equina.
The stenosis is usually a result of bone spurs that may encroach upon the limited space in the canal. The bone spurs may be a result of degenerative changes in the spine or normal age-related changes.
Other causes of spinal stenosis include herniated intervertebral disk, thickening of the ligaments, tumors, etc. The patients affected by lumbar spinal stenosis complain of symptoms due to compression of the cauda equina/dural-sac/spinal cord.
The symptoms of lumbar stenosis include radiating pain down the lower extremities. Patients often complain of leg pain aggravated with walking and bending backward. Numbness and tingling in the legs or the feet.
In advanced cases, there may be loss of sensation and weakness of the muscles supplying the lower extremities associated with loss of bowel and bladder control.
Laminectomy or spinal decompression surgery involves the removal of most of the lamina of the vertebrae during the surgery. Compared to laminectomy, laminotomy is the removal of only a part of the lamina. Laminoplasty involves creating a hinge using the lamina to increase the space in the canal.
During the laminectomy surgery, the surgeon gives an incision on the back at the level determined by radiological studies. The surgeon then safely separates the various tissues including the muscles to reach the spinal lamina. Using cutting instruments, the surgeon safely removes the ligamentum flavum to reach the spinal cord.
The lamina is safely removed to create more room for the neural structures. During a laminectomy, other structures compressing the dural sac may also be removed such as bone spurs and herniating intervertebral disk. Care is taken not to remove more than half of the facet joint which may otherwise create spinal instability.
The surgery may be performed only on one side which is known as a unilateral laminectomy or may be performed on both sides known as a bilateral laminectomy. In the case of unilateral laminectomy, the surgery may also be performed using an endoscope. The endoscopic surgery utilizes minimally invasive techniques with smaller incisions.
In patients in whom, the surgery requires extensive decompression that may lead to instability at one or more levels, a lumbar fusion is also performed alongside decompression. The lumbar fusion involves joining adjacent vertebrae using a cage filled with bone graft. The surgery may also utilize screws and rods to stabilize the fusion.
Lumbar laminectomy is only performed in patients with clinical and radiological signs of lumbar spinal stenosis. Conservative management is usually tried first and only in cases where the conservative management has failed, laminectomy is performed.
The majority of the patients go home the same day after surgery but patients with lumbar fusion may require an additional stay. As with any surgery, there may be complications associated with lumbar laminectomy. There may be potential complications of leakage of spinal fluid, hematoma formation, infection, bleeding, nerve injury, or infection.
The images above show some of the instruments used in posterior lumbar spine laminectomy/fusion. The instruments are used to decompress the spinal nerve/dura and also aid in insertion and fixation of implants in the posterior spine if needed.