Spinal Fusion vs. Microdiscectomy
Microdiscectomy is performed mainly for the management of sciatica or lumbar radiculopathy caused by a herniated intervertebral disc. The lumbar fusion surgery may also be performed for lumbar radiculopathy but due to causes such as recurrent disc herniation, multiple disc herniation, instability, spondylolisthesis, lumbar canal stenosis, and in serious diseases such as cancer or infection of the lumbar spine.
Lumbar fusion surgery is an extensive surgery as compared to microdiscectomy, though the fusion surgery may also be done with minimally invasive techniques. Lumbar fusion surgery involves an incision either from the front of the abdomen, or the back, or from the sides.
The surgeon proceeds to remove the intervertebral disc and freshen the edges of the adjoining vertebrae. The surgeon also removes any bone spurs and tissues such as longitudinal ligament or ligamentum flavum that may be narrowing the canal. The canal may also be widened with the removal of parts of the lamina and the facet joint.
The surgeon then introduces a prosthetic cage to decompress the segment and maintain the disc space. The cage and the surrounding area of the intervertebral space are filled with bone graft. The bone graft may be harvested from the patient’s pelvic bone or from a bone bank. The surgeon then uses metallic hardware in the form of screws and rods to fasten the fusion construct.
Over the months, the lumbar fusion construct is fused together naturally. The bone construct removes any abnormal movement between the vertebrae.
Microdiscectomy surgery on the other hand involves the removal of just the herniated part of the intervertebral disc. The surgeon uses a small incision in the back and uses an operating microscope to visualize the operating field. The surgeon removes a small part of the lamina to visualize the disc and proceeds to remove the herniated part.
The microdiscectomy is a minimally invasive surgery that may be performed in an outpatient setting under local anesthesia. The lumbar fusion surgery on the other hand is performed under general anesthesia. After microdiscectomy, patients may be able to go home the same day of the surgery but may require an overnight stay at the hospital following lumbar fusion surgery.
Lumbar fusion surgery although can be used for the management of herniated discs, it is only used in cases where disc herniation is associated with instability of the spine. Lumbar fusion is also used in cases where sciatica is caused due to narrowing of the canal known as lumbar canal stenosis. The fusion surgery is also done due to instability of the spine segment after removal of a herniated disc owing to the loss of disc height and diameter.
Patients with spondylolisthesis have an instability of the segment due to slippage of one vertebra over the other. Spondylolisthesis may lead to disc herniation and narrowing of the canal. The instability may be a result of trauma or due to a deformity present since birth. Lumbar fusion surgery helps to stabilize the spine segment.
Microdiscectomy is a highly successful surgery but some patients may have a recurrent disc herniation due to incomplete removal and weakening of the outer ring. Recurrent disc herniation causing sciatica are better addressed by lumbar fusion surgery.
The rehabilitation following microdiscectomy is short as compared to lumbar fusion. The spine movement of the patient is decreased due to loss of motion about the fused segment. The loss of motion of the involved segment may place extra load over the adjacent segments leading to adjacent segment degeneration.
Further with spinal fusion, in rare cases there may be complications in the form of non fusion, broken hardware or misplaced hardware.
Both microdiscectomy and spinal fusion may be used to address prolapsed intervertebral disc but both have significantly different indications. The decision regarding the type of surgery is based on the patient’s anatomy, disease process and associated conditions. Speak with your spine surgeon to discuss the type of surgery best suited in your case.