Published in Panorama
Fusion Surgery to Correct Spinal Deformities
With the increasing incidence of vertebral and spinal injuries occurring from road accidents and sports activities, spinal fusion surgery has acquired a significant role in setting right the deformities occasioned by these accidents.
What are the conditions for which spinal fusion is indicated? The surgery is used to treat deformity of the spine as in Scoliosis or bone damage caused by tumour, trauma and infection. It is indicated in instances where there is intractable back pain due to disc degeneration or instability which impairs the patient’s quality of life and the condition does not improve with non surgical measures. Often, narrowing or collapse of the disc may result in nerve impingement in some patients, thus producing radiating pain. These candidates are again suitable for fusion surgery. Fusion surgery is effective in treating Spondilolysis and Spondylolisthesis, a condition in which severe pain is caused on account of the forward slippage of one vertebra on the adjacent vertebra. 5% of any general population has this problem, the cause of which is unknown in most instances, though it can result from injury as well, explains Dr.Chandy Chief of Orthopedics, HOSMAT Hospital, Bangalore.
Ideal candidates for spinal fusion are individuals between the ages of 35 and 65 suffering from severe back or neck pain resulting in deteriorated quality of life and in whom all possible nonsurgical treatment modalities have failed to produce desirable outcome. The procedure, however, will trade the pain for some loss of motion.
What is spinal fusion and what does this surgery involve?
Spinal fusion is a surgical procedure aimed to join two vertebrae bones to relieve pain in the back and restore the load-bearing function of the spinal column, explains Dr.Thomas Chandy. The surgery which is extensive and difficult, is performed by a team involving neurosurgeons and orthopaedic surgeons with special training in spine surgery. The procedure involves bridging together one or more sections of the spine that are normally mobile, with bone. This stabilizes the broken spinal bone, allowing the spinal cord to heal with medication. To achieve the stabilization, various kinds of plates, rods and screws made from Titanium, are used and left in the body. These instrumentation items are biocompatible in that they are non-allergic, non-infective and non-irritant, reveal Dr.J.Lakshmikanth, Specialised Spine Surgeon and Dr.Madhusudan, Specialised Neuro Spine Surgeon, HOSMAT, Bangalore.
The use of screws and rods in the spine, for the purpose of spinal fusion, significantly enhances fusion rate and allows patients to mobilize and perform activities more freely, while the fusion process is occurring after surgery.
The bone graft done in such a surgery may be ideally taken from the patient’s own pelvic area. While 90-95% of patients have successful fusion with autograft, the process has its own disadvantages in that another incision is required in the patient’s body – the hip, to harvest the bone graft. This involves greater surgical time, hip pain which could become chronic, bleeding and infection at the site or even damage to the nerve that supplies sensation to the front of the thigh, reveal the doctors.
Alternatively, Allograft may be the answer to these problems, wherein the required amounts of bones are obtained from the bone bank. There are no cells in the bone graft, so there is no chance of a graft rejection but healing is slower than in an autograft bone fusion. Yet another option is using Synthetic Bone Graft Substitutes made from ceramic spheres and coral, materials which are biocompatible, stable in body fluids and are amenable to be shaped suitably as per requirements.
The neck, middle and lower back are commonly the regions where fusion surgery is done, depending on the level of injury, infection or deformity. The success of a spinal surgery largely depends on the solid fusion between selected intervertebral segments, explains Dr.Chandy. The rate of fusion failure, according to the surgeons, ranges from 5% - 35%. The fusion of the bone itself is dependent upon several factors including the patients’ general health condition, whether they have any systemic disorders, hormonal imbalances, nutritional deficiencies, whether they are addicted to smoking, the type of bone graft used and the instrumentations used in surgery. Fusion failure is believed to be higher in smokers, reveals Dr.Chandy.
The surgery which is all-guided with neuro-navigation and use of image intensifier, is not without its own risks, though these are minimal, thanks to technology. Complications include infection, spinal fluid leak, nerve injury, bleeding, failure to fuse, implant failure or the need to re-operate. The major risk is that some patients may not find relief from pain even after surgery, reveal the surgeons.
The surgeons explain that there could be graft overgrowth with possibility of compression on neural structures, there could be secondary spinal canal stenosis and disc or facet joint lesion above or below the fused spinal segments and the fusion itself could take place at the wrong level.
What about the act of bending, and mobility of the patient following surgery? The surgeons reassure that patients will usually be able to do most of their work. Dr.Chandy explains, “The aim of fusion operation is to make the affected area strong and at that level of the vertebra, we do not want any movement; rather, it will be the segments above and below the fused area that will take all the movement. For instance, if two out of the 33 vertebrae are fused, the rest 31 will be moving. If you fuse a larger section, there will be more restriction of movement, not otherwise. If the required fusion is successful then that portion of the spine that you fused will not bend, but you will bend above and below and sometimes because your symptoms are better, you actually can bend more than before surgery!”
The other side of the coin, of course, implies that the demand for movement on the levels above and below the fused levels will be greater and hence the chance of wear and tear at these levels increases; they can degenerate further. However, with proper body mechanics through physio therapy, exercise and weight control, this problem can be dealt with successfully, explain the surgeons.
What about resuming normal sporting activities for sportspersons, following spinal surgery? Dr.Madhusudan is reassuring: “Yes, it’s possible for sportspeople in non-collision sports to go back to their game. But this is not so for those involved in contact sports for high contact sports may bring on problems. Those playing tennis, racquet sports, swimming, jogging can continue as before.”
Can spinal fusion surgery be done in all age groups of people? Once again, the answer is in the affirmative, especially in conditions like Scoliosis where the surgery may be performed on the very young.
Is spinal surgery contraindicated in certain individuals? “No, not unless they have an active infection, in which case we first tackle the infection and then proceed with the surgery,” says Dr.Lakshmikanth.