Surgical Treatment of scoliosis

Surgical treatment is reserved for a small subset of patients who have failed all reasonable conservative (non-operative) measures. They generally have disabling back and/or leg pain and spinal imbalance. Their functional activities are severely restricted and their overall quality of life has reduced substantially.
The goals of surgery are to restore spinal balance and reduce pain and discomfort by relieving pressure off the nerves (decompression) and maintaining corrected alignment by fusing and stabilizing the spinal segments. In some instances, minimally invasive decompressions may be all that is necessary. Surgical stabilization involves anchoring hooks, wires or screws to the spinal segments and using metal rods to link the anchors together (Figure 1). They act as a tether and allow the spine to fuse in the corrected position. Fusion is performed by using the patient’s own bone or using cadaver or synthetic bone substitutes. In more severe cases, spinal segments have to be cut and realigned (osteotomy) or entire segments may have to be removed prior to realigning the spine (vertebral column resection) (Figure 2). There are many different types of surgical procedures designed to treat adult spinal deformities. Surgeons need to customize the surgery for each patient depending on their needs. When larger surgeries are necessary (greater than 8 hours), surgery may be divided into two surgeries 5-7 days apart.
It is important to note that surgery in adults is riskier than in the adolescent. The complication rate is significantly higher and the recovery is a lot slower. Therefore, surgery should only be undertaken as a last resort and only after the patient has a clear understanding of the risks and benefits. All reasonable non-surgical measures should be attempted first. At the same time, when patients are carefully chosen and are mentally well-prepared for the surgery, excellent functional outcomes can be obtained which at times can be a positive life changing experience for a given individual patient.
Recent advances in surgical techniques include less invasive approaches by making smaller incisions as well as using biologic substances to accelerate the fusion process. Use of computer-assisted navigation systems and various forms of spinal cord and nerve monitoring may help in improving surgical precision and accuracy.

Figure 1: A&B) Front and Side X-rays of a patient with post-laminectomy scoliosis. C&D) Postoperative front and side X-rays showing a fusion from the upper thoracic spine to the sacrum.

Figure 2: A) The pink and blue areas represent the areas of bone resection in a vertebral column resection. B) After the vertebra is removed from the back of the spine, a supportive cage is placed between the segments. C&D) Front and side X-rays of a woman with fixed, rigid scoliosis. E&F) Postoperative front and side X-rays show her improved alignment.

Adult Spinal Deformity

Adult spinal deformity refers to abnormal curvatures of the spine in patients who have completed their growth. Thus they are typically seen in males and females over the age of eighteen. The age range of patients seeking treatment for adult scoliosis and other deformities varies widely, however. It is not unusual for patients who are well into their sixties, seventies or even eighties present with symptoms of pain and functional limitations. With increasing life expectancy along with more active lifestyles, the number of older adults requiring treatment has also gone up. Unlike the younger or adolescent patient with a spinal deformity, the older adult presents with a completely different set of problems and challenges to the treating physician.

Causes

There are many different causes of spinal deformity in the adult. The most common varieties include idiopathic scoliosis that was present during adolescence (teenage years) and then became worse during adulthood, deformity that began in adulthood due to degenerative (wear and tear) changes in the spine and deformity that developed later in life after previous surgery during teenage years. Other less frequent causes include curvatures due to osteoporosis (brittle bones), previous fractures of the spine due to an accident, spondylolisthesis (slipped vertebrae) and rarely, infections and tumors of the spine. Adult idiopathic scoliosis:
This is a slow increase in curvature that began during teenage years in an otherwise healthy individual and progressed during adult life. Some of these patients may have had brace treatment during adolescence while others may have never sought treatment during their teenage years. This can occur in the thoracic (upper) and lumbar (lower) spine and has the same basic appearance as that seen in teenagers. They include shoulder asymmetry, a rib hump or a prominence of the lower back on the convex side of the curvature. These curves can get worse in the older patient due to degeneration of the discs which results in settling of the vertebrae (spinal segments). Additionally, arthritis sets in the joints of the spine (facets) which leads to the formation of bone spurs. This can result in pain and stiffness of the back. In more severe cases, patients may also develop shooting pain and numbness down the legs due to pinched nerves.
Adult degenerative scoliosis:
This condition also goes by the name, “de novo” scoliosis. As the name implies, this variety begins in the adult patient due to degeneration of the discs, arthritis of the adjacent facet joints and collapse and wedging of the disc spaces. It is typically seen in the lumbar spine (lower back). It is usually accompanied by straightening of the spine from the side (loss of lumbar lordosis). Pain, stiffness, numbness and shooting pain down the legs are seen in symptomatic patients.
Post-surgical deformity:
This type is seen in patients who had previously undergone spinal surgery either for scoliosis or for degenerative low back conditions. These patients develop a condition called “Flat Back Syndrome” where the lower back has lost its normal inward curvature or lordosis. As a result, patients with this condition are unable to stand upright and are usually “pitched forward”. They are typically seen in patients who have had long fusions of the spine in the past. Another category of post-surgical deformity is “Junctional Kyphosis” which is an angular deformity (kyphosis) that develops just above or below a previous spinal fusion. Both these conditions result in an imbalance of the spine from the side (sagittal imbalance) and lead to progressive low back pain and stiffness.

Symptoms

Unlike teenagers with spinal deformity who rarely complain of pain, adult patients with deformity present with a variety of symptoms. Low back pain and stiffness are the two most common symptoms. In addition, numbness and cramping in the legs and shooting leg pain due to pinched nerves can occur. These symptoms are due to degeneration of the discs and joints leading to narrowing of the openings for the spinal sac and nerves (spinal stenosis). Loss of sagittal balance causes the patients to compensate by bending their hips and knees to try and maintain an upright posture. This puts greater strain on the muscles of the lower back and legs causing the patients to fatigue early. There is a gradual loss of function and a decrease in the activities of daily living.