|
Scoliosis is a three-dimensional deformity of the spine. This deformity can affect the lumbar spine (low back), the dorsal or thoracic spine (high back) or both. Given the aggressive nature of the surgery to correct the spinal curve, it must only be performed in specific cases. Not all spinal curves must be corrected. The factors that are usually taken into account to decide whether or not to perform surgery are the size of the curvature and in particular the speed of progression, the type of curvature, the symptoms and the age of the patient. This decision must always be taken on the basis of assessment by a surgeon specialised in spine surgery. The purpose of surgery is to correct the curvature. Although total correction is hardly ever achieved, in the majority of cases considerable cosmetic improvement is achieved. Prior to surgery the intervention must be carefully planned, taking into account the number of levels that are to be included in the fusion. In general terms, surgery consists in introducing screws in several vertebrae included in the curvature, joining them by means of rods and applying pressure on these bars to indirectly correct the deformity. Lastly, the vertebrae will be fused together, which will make it possible to maintain the correction achieved with the rods; in consequence, this segment will remain rigid, losing all of its mobility. This surgery requires deep general anaesthesia, and also requires the collaboration of neurophysiologists to monitor the medulla after the anaesthesia has been administered. This is done to avoid medullar damage during the intervention to correct the curvature, since reorienting the vertebrae changes the shape of the medullar cavity and as result may compress or stretch the medulla that passes through the cavity of the vertebrae affected by the deformity. Monitoring consists in placing electrodes on the patient’s head and others on the extremities. When the surgeon requests monitoring, which is usually after performing correction movements, the neurophysiologist sends light electrical discharges to the head, which will be captured by the electrodes on the extremities, verifying in this way that the neurons of the medulla have not been damaged. In the case we present corrections were performed from the back of the spine, although in other cases this has to be done from the front (through the abdomen or thorax). The patient is placed face downwards and an incision is made that includes all the vertebrae which are going to be worked on. The vertebrae are accessed by separating the muscles attached to them. The screws are then inserted in the vertebrae that need them, following the surgeon’s assessment (two per vertebrae, one on each side). This will vary from one patient to another. Once they are inserted, all the screws on one side of the vertebrae are assembled on a rod previously shaped. Initially the screws are not completely tightened on the rod, since there has to be a certain amount of leeway to permit performing corrective movements on the curve. Corrective movements should be performed little by little, and after each one the medulla is checked by means of neurophysiologic monitoring to make sure is has not been damaged. After the desired shape has been achieved, the screws are tightened on the rod, and a second rod is used to join the screws on the other side of the vertebrae, tightening the nuts that join the screws to the bar: this will give solidity to the assembly. Lastly, the surface of the vertebrae is scraped with a chisel and a biological or artificial graft is added to stimulate permanent fusion of the segment corrected. The wound is closed, first with the muscles and then with the skin. A drain is placed to avoid excess blood accumulation. This surgery usually requires several days of hospitalisation to allow the patient to recover and to control possible complications. Sometimes a blood transfusion is necessary to compensate blood loss as a result of the surgery. During the first 48 hours patients are advised to remain in bed, lying flat on their back. Once 48 hours have passed the wound is dressed and the drain is removed. If there are no complications, the patient is encouraged to sit up little by little. On occasions a corset or girdle is used for some time to avoid movements or postures that overload the rods and screws. Following release from hospital, treatment at home will include analgesic and anti-inflammatory drugs to control the pain, as well as daily low molecular weight heparin to prevent blood clots. 2 to 3 weeks after surgery, the clips or stitches are removed. During visits to the out-patient clinic, regular X-ray controls will allow checking the bone fusion of the vertebrae. When evidence shows that this has happened (usually about 3 months following surgery) the patient is authorised to remove the corset or girdle. |