Spinal Stenosis Fusion Prognosis
The success of surgery for spinal fusion depends on a number of factors and it is important to consider the likely risks and benefits of the procedue (as well as of continuing conservative treatment) prior to consenting to surgery.
Spinal Fusion Indications
A spinal fusion is used when abnormal or excessive motion in a segment of the spine is creating pain. Some of the conditions that commonly create pain for which fusion could be helpful include:
- Cervical disk herniations
- Spondylolisthesis (slipped vertebrae)
- Scoliosis (S-shaped spine)
- Fractured vertebra
- Lumbar deformity
- Spinal instability
Spinal stenosis can be a result of, or in addition to, these conditions in which case a patient would usually have a spinal decompression surgery and fusion. This can mean a laminectomy or laminotomy, a foraminotomy (to open up the foramen in the spine), or other surgery followed by a bone graft to stabilize the spine.
Recovery After Spinal Fusion
After the graft is in place the body is prompted to form new bone to bridge the gap, fusing the vertebra to the new bone to create a strong and stable segment of spine. This fusion helps to prevent the painful motion between vertebra and to maintain the height of the disc space so that spinal nerves are no longer pinched.
Most spinal fusion surgeries are performed over just one or two levels, fusing two or three vertebra and discs together, respectively. However, some patients have discs removed and grafts placed over multiple levels where spinal instability is pronounced.
As with most spine surgeries, spinal fusion can be performed posteriorly (from the back), or anteriorly (from the front). In some cases the surgeon may use both approaches to ensure proper positioning of the graft and the removal of degenerated (herniated) disc material or bone spurs causing spinal stenosis. Cervical spinal fusion is often done using an anterior approach but the decision is based on a variety of tests, imaging results, and the extent of surgery which is to be undertaken.
Spinal Fusion Risks
As with any surgery, spinal fusion poses a variety of risks. Serious back surgery complications are rare however, and there are many ways to mitigate risk and improve surgical outcome. Differences do exist between spine surgery centres and hospitals and patients are encouraged to do their due diligence and check infection rates and complication rates before choosing a facility at which to have their procedure. Serious complications occur in less than 1% of cases and can include:
- Anesthetic problems
Other risks of surgery to fuse the spine include:
- Urinary difficulties
- Absent or decreased intestinal function
- Graft rejection or pseudoarthrosis
- Hardware failure
- Nerve trauma, dural tear, and cerebrospinal fluid leak or infection
One key risk of spinal fusion surgery is simply that the bone will not fuse. This happens in some five to ten percent of cases and is more likely in those who smoke, are obese, or have undergone radiation therapy for cancer. The biggest risk of spinal fusion however, is that the surgery fails to relieve symptoms such as back pain, sciatica, paraesthesia and so on. Some twenty percent of those undergoing fusion continue to have lower back pain symptoms and this is most likely where multiple spinal levels are fused.
The fusion of multiple vertebra can cause the spine to become too rigid which may create its own type of pain. In addition, removal of discs and fusion of the spine can shift stress to the adjacent segments (i.e. those above and below the site of fusion), causing more rapid degeneration of tissues in those areas.
Spinal Fusion Success Rate
Several studies have been carried out to determine the success rate of spinal fusion, with around 90% success typically reported. All this means, however, is that the bone fuses in 90% of cases, not that symptoms are resolved adequately. There is rarely a 90% success rate for pain relief or improved mobility and function. In many cases the road to recovery after spinal fusion is long and arduous, involving careful attention to exercise, diet, and lifestyle to facilitate a good outcome.
It can take weeks, months, or even a year or more to recover from spinal fusion. The more involved the surgery the longer it can take to heal. Those in good general health who don’t smoke, are not obese, and who follow post-surgical guidelines closely will usually do well and recover quickly. It is important not to rush recovery after spinal fusion as shocks to the spine can jolt the graft before it has properly fused. This can be difficult to remember when the initial pain subsides after surgery and patients experience relief from chronic back pain due to the decompression of spinal nerves.
Typically, pain subsides within a few weeks or months of surgery, and mobility and strength are regained over the course of the first year after surgery. A well maintaned physical rehabilitation schedule and good nutrition, as recommended by a physician, greatly increase success rates and can expedite healing.
Successful spinal fusion helps to stabilize and support the spine but does not allow for the natural movement that takes place between unfused vertebra. As such, anyone considering spinal fusion should understand their options for more minimally invasive procedures and appreciate the risks involved before undergoing this type of surgery for spinal stenosis and back pain.