Lumbar Fusion Surgery
Lumbar fusion is a surgical technique used to fuse two or more vertebrae of the lower spine, thus eliminating any motion between them. They may be fused with the help of a bone graft or bone-like materials. The fused vertebrae behave as a single unit and thus prevent any motion which causes pain or instability.
Lumbar fusion surgery may be done to treat patients suffering from herniated intervertebral disks, spinal deformities, spinal instability, spinal stenosis, spondylolisthesis, fracture, tumor, etc. The surgery often utilizes instrumentation in the form of screws and rods to stabilize the fusion.
The lumbar fusion surgery may be performed through a number of different approaches depending upon diagnosis and surgical requirements. It may be performed from the front of the abdomen, known as anterior lumbar interbody fusion.
It may be performed from the sides, which is known as lateral lumbar interbody body fusion. In the case when it performed from the back, it is known as posterior lumbar interbody fusion, posterolateral lumbar fusion, or transforaminal lumbar interbody fusion.
The patients are anesthetized during the procedure and the surgeon gives an incision according to the approach used for the surgery. The tissues and muscles are separated to reach the vertebra. The ends of the vertebrae are prepared to receive a bone graft with or without a metallic cage. The cage helps to maintain the necessary intervertebral space and the bone graft accelerates the fusion.
The bone graft may be taken from the patient’s own body, known as an autograft. The autograft is usually taken from the patient’s pelvic bone during the same surgery. A solid bone may also be grafted to provide structural support. The surgeon may also utilize bone graft taken from a bone bank or may use synthetic materials that accelerate fusion such as Bone Morphogenic Protein (BMP).
During the surgery, the surgeon may also decompress the spinal cord/dural-sac with a procedure known as a laminectomy. The laminectomy involves the removal of the lamina to increase the space for the spinal cord/dural-sac.
The surgeon may stabilize the fusion with the help of rods and screws. The stabilization with rods and screws helps to keep the involved vertebrae in place and accelerates their fusion.
Most patients are discharged the same day of the procedure and are able to walk right after the surgery. The patients undergo rehabilitation and experience marked improvement in their symptoms.
Lumbar fusion eliminates the stretching of the ligaments, impingement of the nerves, and movement of the facet joint, thus eliminating the source of the pain. Lumbar fusion also stabilizes spinal instability caused by trauma or degeneration. The correction of spinal deformities also involves the fusion of some of the vertebrae.
The lumbar fusion is major surgery and like any major surgery, it carries a risk of potential complications. There may be complications of intraoperative bleeding, spinal fluid leakage, or injury to the nerves, etc. There may risk of blood clots, implant breakage, or infection of the surgical site.
Over a longer duration, there may be a failure of fusion of the vertebrae which may cause instability of the spine. The vertebra adjoining the fused vertebrae may experience early degeneration due to excessive motion.
Lumbar fusion is a commonly performed orthopedic spine procedure with excellent results. There are newer techniques that utilize minimally invasive techniques to reduce tissue injury and allow faster rehabilitation.
The images above show the pedicle screws used in minimally invasive lumbar fusion. The minimally invasive technique utilizes percutaneous insertion of pedicle screws and rods for fusion. The reduced cutting of the tissues results in earlier rehabilitation and reduced pain.
The T-PAL instrument and cage are used during performing traditional transforaminal lumbar interbody fusion. The transforaminal approach utilizes an incision at the side of the spinous process. The bone cage may be made of PEEK (poly-ether-ether-ketone) polymer with radiographical markers.