Spinal fusion is a surgical procedure that is performed in the cervical and lumbar spine to reduce pain by decompressing the nerve roots and spinal cord and stabilize the area by creating a solid bridge of bone between two or more vertebrae. Discs that become damaged either through trauma or degeneration can be a source of pain. If part of a disc moves out of its normal position it can cause pressure on the central spinal cord or on the individual nerve roots that exit from the spinal canal at each vertebral level. Disc disruption and degeneration can be a source of neck pain as well as cause neurologic symptoms which may include pain, numbness or weakness that radiates to the extremities. Spinal fusion is a surgical procedure that involves removing a damaged or diseased disc and stabilizing the area by implanting a graft or instrumentation that is affixed to the adjacent vertebrae. Fusion decreases motion at that level caused by segmental instability. This reduces the mechanical neck pain caused from excess motion in the spinal segment.
A spinal fusion is typically performed on an outpatient basis with the patient under general anesthesia. The procedure requires one to three hours of surgical time dependent upon several factors unique to each patient. There are different approaches for accessing the spine and placing the bone graft. The surgeon may approach the spine from the back (posterior), the front (anterior), or the side (lateral). The approach depends on the level of the spine that will be fused and other factors. Minimally invasive surgery is an option for some spinal fusions. In these procedures, rather than cut through the muscles over the spine, the neurosurgeon makes a small incision and uses specialized instruments to push the muscle out of the way and access the spinal vertebrae to be fused. The smaller incision and minimal trauma to the muscle tissue may mean less pain and faster recovery.
Once taken to the operating room, anesthetized, and properly positioned; the surgeon creates access to the vertebrae being fused. The surgeon makes an incision in one of three locations: in the neck or back directly over the spine (a posterior approach), on either side of the spine (a lateral approach), or in the abdomen or throat from the front (an anterior approach). Your surgeon will discuss the preferred approach for accomplishing your fusion. Once the surgeon safely creates a window to see the spine, the damaged disc is partially removed with surgical tools. This is called a discectomy. Some of the disc wall is intentionally left behind to help contain bone graft material. Once the disc has been removed between the vertebrae, a fusion is performed. This procedure allows the surgeon to fill the space left by removing the disc with a block of bone graft. Placing a bone graft between two or more vertebrae causes the vertebrae to grow together, or fuse. The surgeon prepares the bony surfaces for a fusion. The bones are slightly spread apart to make more room for the bone graft. This distracts the bones to realign proper curvature and enlarges the openings to relieve pressure off any pinched nerves. A cage implant that may be filled with bone graft is placed in the now empty disc space between the two vertebral bodies. The spacer or fusion cage may be made of bone, titanium, or plastic. Bone graft inside the disc space will go on to fuse, healing the two bones together in this area. By using metal plates and screws, the vertebra can be held rigidly in place while the fusion heals. Fluoroscopy (live X Ray imaging) is utilized to facilitate proper positioning of the spinal hardware. The incision is then closed.
Patients are typically discharged home the same day or the next morning following surgery. Pain from the procedure is usually limited and improves markedly within two to three days. Nerve symptoms such as pain, numbness, and weakness are often dramatically improved within hours of the surgery, but in some cases can take weeks or even months to recover. Most patients return to light work within a week or two of surgery and to full duty six weeks following the procedure.