A posterior lumbar laminectomy which is also called a decompression, is done to treat pain caused by degenerative conditions in the lower back. Disc degeneration, bone spurs, and other conditions can cause narrowing of the spinal canal and pressure on the spinal nerves (radiculopathy) exiting the spine. A laminectomy removes part of the vertebral lamina to reduce this pressure. Following the laminectomy, bone grafts can be used for fusing vertebrae to stabilize and support the spine. In patients with little or no instability, where the vertebrae, discs, and surrounding tissues fit tightly together, adding instrumentation is not necessary and the bone grafts can sufficiently stabilize the spine.
An incision is made in the middle of the low back. Surgical instruments are used to remove the spinous processes and lamina. Bone spurs or other sources of spinal nerve compression are also removed. The extra space provided alleviates pressure.
Preparing for Fusion
A motorized instrument (bur) is used to remove the top (cortical) layer of the transverse processes to prepare a site for fusing the vertebrae. The layer of bone is removed so that the underlying layer can fuse to the bone grafts that will be placed at the sides of the spine.
Bone grafting can be done with pieces of a patient’s own bone (autograft), processed bone from a bone bank (allograft), or a bone graft substitute (demineralized bone, ceramic extender, or bone morphogenetic protein). To harvest a patient’s own bone for grafting, bone from the iliac crest will typically be removed through the same incision that was made to access the spine. The harvested bone is then placed along the prepared site where the top layer of bone was removed. This bone eventually grows in place, fusing the spine and providing additional stability.
The incision is closed and dressed to complete the procedure. A brace may be required for up to 3 months after surgery. For a period of time, it is common to experience some pain where the bone graft was removed from the pelvis.