Spine Surgery :: Spine Fusion, General
Low back pain is one of the most common ailments of western societies.
Many patients suffering of chronic low back pain think that a spinal fusion is the universal answer to their problems. Yet, this surgery is only successful if it is done for the correct reasons. Chronic low back pain is often secondary to deep ligament and muscle injuries that cannot be helped by surgery.
To make matters more confusing, about 30% of the normal population that have never had any back problems have abnormal findings on imaging studies such as MRI, CT scan, myelograms and plain X-rays. The real art of the practitioner is therefore to figure out whether the abnormality seen on the imaging study is really the cause of the pain.
Common spine problems that usually respond well to fusion surgery are:
- Gross instability of the spine (abnormal motion).
- Severe degenerative disc disease with hypermobility.
- Spondylolisthesis (slippage of one vertebra over another).
- Facet (joint) disease that has not responded to other treatments.
- Fractures or tumors.
Finally, there is the problem of discogenic pain! This means pain that originates from the discs of the spine. By large, this is the area that is the most controversial.
In general, a disc that responds positively to a provocative discogram is considered to be a pain generator. The treatment consists of removing the disc and fusing the vertebra above and below the disc together.
A provocative discogram consists of introducing a thin needle into the disc (with the patient awake and lightly sedated) and increasing the pressure in the disc by injecting saline solution or X-ray dye. X-rays and/or a CT scan are usually done at the same time to study the internal anatomy of the disc.
Many spine fusions have been done solely on the basis of this test with functional results that have not always been good despite a successful anatomical fusion. Recent studies have shown the following:
- A disc that appears to be causing pain but that has normal or near normal internal structure does not respond well to fusion.
- Fusion works best when the disc is so abnormal that the space between the vertebras has collapsed 50% or more.
- Actually, the best results appear to be obtained when the disc is so abnormal and collapsed that the surrounding bone becomes irritated.
In the cases where the disc is near normal but causing pain, the best surgical treatment might be thermocoagulation where a thin wire is introduced in the disc space to coagulate and seal the fissures in the disc and, at the same time, destroy the sensitive nerve endings within it. This surgery does not work as well when the disc is significantly collapsed, which is where fusion surgery has more success! However, in the case of discogenic pain, fusing more than two levels have not shown good outcomes.
Therefore, if one or two discs of the spine are proven to cause pain, thermocoagulation might be of help if the discs are near normal and fusion surgery might be of help if the discs are significantly collapsed.
Please bear in mind that those procedures are options of last resort. Back pain of all causes responds well to non-surgical treatments and one has to have exhausted all other treatment options before considering surgery.
In fact, surgery should only be considered if there has been at least 3 months of non-surgical treatment including active back strengthening exercises, not solely flexibility exercises, rest or medications.
Finally, one must view one’s back like a car. After being fixed, it still needs to be maintained. Do you think your car will be able to run without gas or oil once the mechanic has repaired the engine? After surgery, there will be a need for an active exercise program, weight loss if necessary and use of good back mechanics.
