What is spinal fusion surgery?
A spinal fusion surgery permanently joins together two or more vertebrae. The goal is to “fuse” problematic areas of the spine together so that they grow into a single, solid bone. This surgery prevents the fused vertebrae from moving, so it is often used in cases where vertebral movement is the source of pain.
Conditions that may be relieved with spinal fusion surgery include scoliosis, spinal stenosis, spondylolisthesis, spinal fracture, and degenerative disc disease.
The surgical procedure
Surgeons have multiple techniques available to them for spinal fusions. An anterior approach to the spine involves an incision in the front of the body, usually in the lower abdomen for access to the lower spine. In a posterior approach, the incision is made in the back. A lateral approach involves an incision in the side of the body. The approach a surgeon elects to take will depend on the nature of the problem and the location of the vertebrae they plan to fuse.
This surgery is sometimes combined with a laminectomy, also known as a spinal decompression. In this procedure, bone or diseased tissue that is putting pressure on the spinal nerves is removed.
After an incision has been made and a laminectomy, if necessary, has been performed, the surgeon will begin the process of fusing the vertebrae together. All spinal fusions involve a bone graft, a small piece of transplanted bone that will grow into the space between the vertebrae in order to fuse them permanently together. An autograft procedure involves harvesting bone from the patient’s hip. In an allograft procedure, the bone material used for the graft is harvested from a cadaver. Artificial bone graft materials are also available, including demineralized bone matrices (a putty-like material made from cadaver bones, usually combined with other grafts), bone morphogenetic proteins (synthetic proteins that promote bone formation), and ceramics (synthetic calcium/phosphate implants that are similar to autograft bone).
After the bone graft has been placed, the surgeon may also implant hardware to help hold the spine still while the bone grows. Internal fixation may involve plates, screws, and rods. In some cases, the patient may be asked to wear a brace to prevent the spine from moving.
The recovery process
After the fusion surgery is complete, the patient will be observed in the hospital for 3 to 4 days before being discharged. During this time, they will receive pain medicine; this may be given orally, by injection, or intravenously. A patient may be given a pump that allows them to control their levels of pain medications. During the first few days after the procedure, patients may not be able to eat solid foods. In these cases, nutrients will be delivered via IV.
If an autograft was harvested from the patient, they may feel additional pain and need monitoring of healing at the harvest site. In rare cases, patients may experience long-term pain at the bone graft site.
Bed rest is usually not necessary after this surgery. Patients may be encouraged to wear a back brace to stabilize the spine while the bone grows.
The process of achieving full fusion may take several months as the bone slowly grows into the space between the vertebrae. Many patients report decreased pain even before the fusion process is complete.
Patients who have undergone spinal fusion will need to work with a physical therapist or rehabilitation specialist to learn how to sit, walk, and stand while keeping their spine in proper alignment. Directly after surgery, patients may be restricted only to light activity; as their pain decreases, they will be encouraged to increase their activity level. While spinal fusion will cause patients to lose some range of motion in the spine, most fusion surgeries involve only small segments of the spine and should not place too many limits on most activities of daily living.
A healthy lifestyle may improve a patient’s chances for a successful outcome from this surgery. Smokers are at risk of developing pseudarthrosis, a condition that occurs when the bone graft fails to fully develop. Additional surgery may be necessary in these cases to ensure that the bones fuse correctly.
In some cases, patients who undergo this surgery may find that their original symptoms do not go away or return over time. Patients with chronic back often report some continued pain post-surgery. In some cases, the areas above and below the site of the fusion will experience increased stress due to lack of movement in the fused area, and future pain may develop at those sites.
Blausen.com staff. "Blausen gallery 2014". Wikiversity Journal of Medicine. DOI:10.15347/wjm/2014.010. ISSN 20018762.