The most commonly performed surgery in the treatment of low back pain is lumbar fusion surgery. The goal of lumbar fusion surgery is to fuse together individual vertebral bones in the lower back. When two or more vertebrae are held together in this way, it prevents the vertebrae from moving in relation to one another. After the procedure, the lumbar spine is less mobile in that fused area, but that restricted motion can greatly lessen lower back pain.
What is involved in lumbar fusion surgery?
If you have ever broken a bone, you know that new areas of bone will knit together during healing. Lumbar fusion surgery is similar in some ways except that the surgeon will set in motion bone “healing” between affected vertebrae using special substances called bone grafts. In lumbar fusion surgery, the affected vertebrae are isolated and intervertebral discs are surgically removed. The surgeon replaces the disc (which is normally made of protein and cartilage) with a bone graft. The bone graft will promote bone growth between the vertebrae, fusing them together.
What is a bone graft?
Modern orthopedic spine surgeons have several options for bone graft material. Bone grafts can be natural or artificial. The traditional method for bone grafting was to remove a small amount of bone from the patient’s hip/pelvis. The advantage of this is that the patient’s own bone is used, so there is no risk of tissue rejection and there is better chance of fusion healing. The main disadvantage is that it requires an additional incision in the donor site that can be painful during healing. In most cases, donor bone can be used from a cadaver, if the patient desires a natural bone solution but does not want to use bone taken from his or her own hip.
Fortunately, several artificial substances are available that perform similarly to natural bone. These include demineralized bone matrices, bone morphogenetic proteins, synthetic calcium/phosphate ceramics, and bioglass. There are advantages and disadvantages of each substance, which your spine surgeon can explain.
How will my spine be held in place during healing?
Unlike a broken arm or leg, there is no real “cast” for the spine. Instead, surgeons can do one or more things to hold the spine in perfect position. The patient may need to wear a back brace until the new bone has formed and the vertebrae are fused. Since the vertebrae need to be held in perfect alignment during bone healing, the surgeon may place metal hardware along the spine to hold it in alignment. This may involve screws and plates and rods. The main benefits of internal fixation, as this process is called, is that the patient can ambulate (walk around) soon after the procedure and the spine will be held in better alignment than could be achieved by a simple back brace.
What are the risks of lumbar fusion surgery?
Infection, bleeding, and pain are risks associated with any surgery. These risks can be minimized through antibiotics and careful surgical technique, but not completely avoided in all cases. Incomplete vertebral bone fusion is a possible risk, though this occurs much more often in people who smoke.
Are there alternatives to lumbar fusion surgery?
Yes, there are a number of alternatives to and variations in lumbar fusion surgery. Your orthopedic spine surgeon can discuss these alternatives during consultation.