Spinal fusion is a surgical procedure in which two or more vertebrae are permanently joined into one solid bone with no space between them. Vertebrae are the small, interlocking bones of the spine.
In spinal fusion, extra bone is used to fill the space that usually exists between the two separate vertebrae. When the bone heals, there’s no longer space between them.
Why get Spinal Fusion surgery?
Spinal fusion is performed to treat or relieve symptoms of many spinal problems. The procedure removes mobility between the two treated vertebrae. This may decrease flexibility, but it’s useful for treating spinal disorders that make movement painful. These disorders include:
- Spinal Stenosis
- Herniated Discs
- Degenerative Disc Disease
- Fractured Vertebrae that may be making the spinal column unstable
- Scoliosis (curvature of the spine)
- Kyphosis (abnormal rounding of the upper spine)
- Spinal weakness or instability due to severe arthritis, tumors, or infections
- Spondylolisthesis (a condition in which one vertebra slips onto the vertebra below it, causing severe pain)
A spinal fusion procedure may also include a discectomy. When performed alone, a discectomy involves removing a disc due to damage or disease. When the disc is removed, bone grafts are placed into the empty disc space to maintain the right height between bones. A surgeon uses the two vertebrae on either side of the removed disc to form a bridge (or fusion) across the bone grafts to promote long-term stability.
When spinal fusion is performed in the cervical spine along with a discectomy, it’s called cervical fusion. Instead of removing a vertebrae, the surgeon removes discs or bone spurs from the cervical spine, which is in the neck. There are seven vertebrae separated by intervertebral discs in the cervical spine.
How is Spinal Fusion performed?
Spinal fusion is performed in the surgical department of a hospital. It’s done using general anesthesia, so the patient won’t be conscious or feel any pain during the procedure.
During the procedure, the patient will be lying down and have a blood pressure cuff on their arm and heart monitor leads on their chest. This allows the surgeon and anesthesia provider to monitor heartbeat and blood pressure during surgery. The whole procedure may take several hours.
The surgeon will prepare the bone graft that will be used to fuse the two vertebrae. If the patient’s own bone is being used, the surgeon will make a cut above the pelvic bone and remove a small section of it. The bone graft may also be a synthetic bone or an allograft, which is a bone from a bone bank.
Depending on where the bone will be fused, the surgeon will make an incision for placement of the bone. The bone graft will be placed between the affected vertebrae to join them. Sometimes, the graft material is inserted between the vertebrae in special cages. Some techniques place the graft over the back part of the spine.
Once the bone graft is in place, the surgeon may use hardware to implant plates, screws, and rods to keep the spine from moving. This is called an instrumented fusion.
After a spinal fusion, patients need to stay in the hospital for a period of recovery and observation. This generally lasts three to four days. Initially, the doctor will want to observe the patient for reactions to the anesthesia and surgery. A patient’s release date will depend on their overall physical condition, the physician’s practices, and the patient’s reaction to the procedure.
After surgery, patients are instructed about new ways to move, since flexibility may be limited. This includes new techniques to walk, sit, and stand safely. Many patients also may not be able to resume a normal diet of solid food for a few days.
After patients leave the hospital they usually need to wear a brace to keep the spine in proper alignment. Patients might not be able to resume normal activities until the body has fused the bone into place. Fusing may take up to six weeks or longer.
Full recovery from spinal fusion will take three to six months. A patient’s age, overall health, and physical condition affect how quickly they heal and are able to return to their usual activities.
Patients are recommended to consult their doctor if they exhibit signs of infection, such as:
- Redness, tenderness or swelling
- Wound drainage
- Shaking chills
- Fever higher than 100.4 F (38 C)
Complications following Spinal Fusion
Spinal fusion, like any surgery, carries the risk of certain complications, such as:
- Blood clots
- Bleeding and Blood loss
- Respiratory problems
- Heart Attack or Stroke during surgery
- Inadequate wound healing
- Reactions to medications or anesthesia
Spinal fusion also carries the risk of the following rare complications:
- bin the treated vertebrae or wound
- Damage to a spinal nerve, which can cause weakness, pain, and bowel or bladder problems
- Additional stress on the bones adjacent to the fused vertebrae
- Persistent pain at the bone graft site
- Blood clots in the legs that can be life-threatening if they travel to the lungs
Physical activity too soon after surgery can result in pseudarthrosis (a bone fracture that has no chance of mending without intervention), which may prompt a second surgery. Smoking, diabetes, and advanced age can also increase the risk of developing pseudarthrosis.
The most serious complications are blood clots and infection, which are most likely to occur during the first weeks following surgery.
In certain cases, the implant of plates, screws, and rods will need to be removed if it’s causing pain or discomfort.
Implant Failure in Spine Surgery
An instrumented fusion can fail if there is not enough support to hold the spine while it is fusing. Therefore, spinal hardware may be used as an internal splint to hold the spine while it fuses after spine surgery. However, like any other metal it can fatigue and break (sort of like when one bends a paper clip repeatedly). In very unstable spines, it is therefore a race between the spine fusing (and the patient’s bone then providing support for the spine), and the metal failing.
Implant failure especially early in the postoperative course after back surgery, is an indicator of continued gross spinal instability. The larger a patient is and the more segments that are fused, the higher the likelihood of implant failure.
Spinal fusion can be an effective treatment for fractures, deformities or instability in the spine. But study results are more mixed when the cause of the back or neck pain is unclear. In many cases, spinal fusion is no more effective than nonsurgical treatments for nonspecific back pain.
It can be difficult to be certain about what exactly is causing back pain, even if a herniated disk or bone spurs show up on X-rays. Many people have X-ray evidence of back issues that have never caused them any pain. So back pain might not be associated with whatever problem has been revealed on a patient’s imaging scans.
Even when spinal fusion provides symptom relief, it does not prevent a patient from developing more back pain in the future. Most of the degenerative conditions in the spine are caused by arthritis, and surgery will not cure a body of that disease – though it may offer greater long-term comfort for some.
Immobilizing a section of the spine places additional stress and strain on the areas around the fused portion. This may increase the rate at which those areas of the spine degenerate, which may lead to additional spinal surgery in the future.
Alternative Treatments to Spinal Fusion
Stem cell therapies are an exciting treatment alternative to spinal fusion and lumbar disc replacement. In many cases, a patient’s own adult stem cells may be able to replace the need for surgery.
This minimally invasive treatment can lead to dramatic improvement in low back pain, while significantly decreasing the risks and recovery time associated with traditional invasive back surgery. The back injection administered into a damaged disc during the stem cell procedure may decrease painful inflammation, repair damaged disc cartilage and improve hydration and disc height.
Stem cell therapy can dramatically reduce the number of days lost to disability and return patients to work and recreation much quicker when compared to spinal fusion surgery.
This type of therapy also offers relief for patients who have already undergone spinal fusion surgery by helping the fusion heal.
Spinal fusion surgery changes how the spine works by immobilizing one portion of it, the areas above and below the fusion are at an increased risk for wear and tear. They may become painful if they deteriorate and it can lead to additional problems.
Stem cells and other regenerative medicine work not to immobilize but rather regenerate the injured parts of the back. Regenerative medicine can also help patients who suffer from spinal fusion side effects and complications.