Scoliosis

Scoliosis is the abnormal sideways curvature of the spine. The spine curves from side-to-side to different degrees, and some of the back bones rotates slightly, making the hips or shoulders appear uneven.

 

Types of Scoliosis:

 

The scoliosis has been classified according to different parameters, some of which are:

 

Classifying Scoliosis by the Shape of the Curve: Scoliosis is often categorized by the shape and rigidity of the curve, as either structural or nonstructural.

 

In structural scoliosis, the spine not only curves from side to side, but the vertebrae also rotate, twisting the spine. As it twists, one side of the rib cage is pushed outward so that the spaces between the ribs widen and the shoulder blade protrudes (producing the rib-cage deformity, or hump). The other half of the rib cage is twisted inward, compressing the ribs.

A nonstructural curve does not twist but is a simple side-to-side curve. These are usually non rigid curve that gets corrected with posture.

 

Classifying Scoliosis by Its Location: Scoliosis most commonly develops in the thoracolumbar region, which is the area between the upper back (the thoracic area) and lower back (lumbar area). It may also occur only in the upper back or lower back.

 

Classifying Scoliosis by Its Direction: The direction of the curve in structural scoliosis is determined by whether the convex (rounded) side of the curve bends to the right or left. For example, a physician will diagnose a patient as having right thoracic scoliosis if the apical vertebra is in the thoracic (upper back) region of the spine and the curve bends to the right.

 

Classifying Scoliosis by Its Magnitude: The magnitude of the curve is determined by taking measurements of the length and angle of the curve commonly known as Cobbs angle on an x-ray view.

 

Classifying Scoliosis by Its Cause (Scoliosis research Society):

 

Idiopathic scoliosis

• Early Onset - before 5yrs of age
• Late onset - after 5yrs of age

Idiopathic kyphosis

• Type 1 - classical thoracic Sheuermann's disease
• Type 2 - 'apprentices spine' - thoracolumbar or lumbar

Neuromuscular deformities

• Cerebral palsy
• Poliomyelitis
• True NMD
• Familial dysautonomia
• Malignant hyperpyrexia
• Deformities associated with Neurofibromatosis
• Mesenchymal deformities
• Connective tissue disorders
• Mucopolysaccharidoses
• Bone Dysplasias
• Metabolic bone disease
• Endocrine disorders

Traumatic

• vertebral
• extravertebral

Infection

• Pyogenic
• TB

Tumours

• Intradural
• Extradural
• Paravertebral

Syringomyelia

Metastases

Spondylolisthesis

• Dysplastic
• Isthmic
• Degenerative
• Traumatic
• Pathological

Spinal deformity in adults

• True adult deformities
• Adult presenting deformities

 

 

Scoliosis Classification According to International Scoliosis Society:

• Idiopathic
• Infantile 
• Juvenile
• Adolescent
• Adult
• Resolving or progressive
• Neuromuscular
• Neuropathic
• Upper Motor neurone Lesions - CP, Spinocerebellar degeneration, cord tumor, cord trauma, other
• Lower Motor Neurone Lesions- polio, trauma, spinal muscular atrophy, myelomeningocoele
• Myopathic - Muscular dystrophies (Duchenne, Limb-Girdle, FSH), Arthrogryphosis, Congenital hypotonia, myotonia dystrophica
• Congenital                                                                                                                                   

Failure of Formation - Partial Unilateral (wedge vertebra), Complete Unilateral (Hemivertebra)

Failure of Segmentation - Unilateral (Unilat. unsegmented bar), Bilateral (Block vertebra)

Mixed 

Others

Neurofibromatosis  

Neural defects - Myelomeningocoele, spinal dysraphism

• Connective Tissue -Marfans, homocystenuria, Ehlers-Danlos
• Traumatic Fracture/dislocation, irradiation
• Tumours
• Bone Dysplasias - Achondroplasia, spondyloepiphyseal dysplasia, diastrophic dwarfism, mucopolysaccharidoses
• Rheumatoid   
• Metabolic - Rickets, juvenile osteoporosis, Osteogenesis imperfecta
• Soft tissue - burns, postempyema
• Functional - postural, leg length, muscle spasm, Hysterical 

 

 

Assessment: Spinal deformity may be assessed clinically and radiologically. The physician attempts to define scoliosis by the following characteristics:

• The shape of the curve.
• Its location.
• Its direction.
• Its magnitude.
• Its causes, if possible

 

Clinical Assessment: Morphometric parameters is measured at each visit. Range of motion and spine flexibility is also assessed. Normally, with the patient standing a plumb line dropped from the spinous process of C7 should fall in the gluteal cleft. The distance from this line to the gluteal cleft is a measure of compensation. 

Adam's Test/Position - patient bends forward. The effect of forward bending on the curve should be noted. A 'rib hump' will appear with a structural scoliosis on the side of the curve convexity.

With the patient sitting & facing away from examiner, pelvic obliquity should be assessed (for structural vs. functional curve)

Neurological examination is essential, with attention to sexual development and associated congenital anomalies. 

With congenital spinal deformity attention should be paid to the cardiac, neurological and genitourinary systems.

 

Radiological Assessment: Standing PA film of whole spine on one film. PA gives less radiation to breasts and ovaries 

Lateral bend films - Supine with maximum voluntary lateral bend. Determines flexibility. Differentiates structural from compensatory curves. Indicated in preoperative evaluation for Double curve, Low curve to see if L4 corrects.

Lateral films Standing - To measure kyphosis and lordosis 

Cobb angle - involves drawing perpendicular lines through the end plates of the most tilted vertebrae of the curve and measuring the angle of the intercept. These vertebrae are known as the end-vertebrae, while the vertebra at the centre of the curve is the apical vertebra. Line drawn along upper end plate of upper end vertebra and lower end plate of lower end vertebra. Perpendiculars drawn from these lines. Angle of intersection measured. For double curve, one vertebra is upper end vertebra for lower end curve and lower end vertebra for upper curve (transitional curve). Only one line drawn on this vertebra. In future, measurement should always be from same vertebrae.  True size of curve demonstrated on film taken perpendicular to plane of apical vertebra (plan d'election') Hypokyphosis demonstrated on film taken at 90o to this It may be used to measure both lateral curves of scoliosis and sagittal curves of kyphosis. It has been said to be an inaccurate description of the deformity in an oblique projection and have little importance in isolation.

 

Cause of Scoliosis:

 

Possible Causes of Idiopathic Scoliosis: In 80% of patients, the cause of scoliosis is unknown. Such cases are called idiopathic scoliosis. (Idiopathic simply means without a known cause.) Idiopathic scoliosis is the most common form of this spinal condition. It is thought to be due to multiple, poorly understood inherited factors, most likely from the mother's side. However, the severity often varies widely among family members who have the condition, suggesting that other factors must be present.

• Endocrine system - Patients with idiopathic scoliosis often taller. Growth hormone levels found to be normal. Studies on somatomedin levels conflicting but significant differences found
• Postural equilibrium - Abnormalities in the vestibular system in the brain stem in scoliotics have been demonstrated. Scoliosis induced in bipedal rats by destruction of brain stem. Proof not conclusive
• Neurotransmitter - Scoliosis experimentally produced by removing pineal gland in chickens. No specific neurotransmitter defect identified
• Genetics - Increased incidence in affected relatives found. Sharp drop from first-, second-, and third-degree relatives. Chance that child will have scoliosis with affected relative:  Mother and father - 80%, Mother and sister - 20%, Mother - 10%, Sister - 3%. Indicative of multifactorial mode of inheritance. 
• Other Biologic Factors. A number of other biologic factors are being investigated for some contribution to scoliosis:

Abnormalities in collagen, the critical structural protein found in muscles and bones. Enzymes known as matrix metalloproteinases are involved in the repair and remodeling of collagen. Researchers have found high levels of the enzymes in the disks of patients with scoliosis, which suggests that the enzymes may contribute to curve progression. Elevated levels of the enzymes can cause abnormalities in components in the spinal disks, contributing to disk degeneration.

A possible defective gene responsible for production of fibrillin, an important component of connective tissue, which makes up bones and muscles.

Abnormalities in a protein called platelet calmodulin that binds to calcium. This protein acts like a tiny muscle and pulls clots together. Measuring levels of this protein may eventually help predict whether scoliosis will worsen.

 

Possible Cause of Congenital Scoliosis: Congenital scoliosis is caused by inborn spinal deformities that may result in the development of absent or fused vertebrae. Kidney problems, particularly having only one kidney, often coincide with congenital scoliosis. The condition usually becomes evident at either age two or between ages eight and 13 as the spine begins to grow more quickly, putting additional stress on the abnormal vertebrae. It is essential to diagnose and monitor such curvatures as early as possible, since they can progress quickly. Early surgical treatment--before age five--may be important in many of these patients to prevent serious complications.

 

Possible Causes of Degenerative Lumbar Scoliosis in Adults:  Degenerative lumbar scoliosis is a condition that typically develops after age 50. With this condition, the lower spine is affected and is usually due to disc degeneration. Osteoporosis, a serious problem in many older adults, is not a risk factor for new-onset scoliosis, but it can be a contributing factor. In most cases, however, it is not known why scoliosis occurs in adults.

 

Possible causes of  Neuromuscular Scoliosis: Scoliosis may be a result of various conditions that affect bones and muscles associated with the spinal column. They include the following:

• Muscle paralysis.
• Muscle deterioration from diseases such as muscular dystrophy, polio, or cerebral palsy.
• Injury to the spinal cord.
• Tumors, growths, or other small abnormalities on the spinal column. For example, syringomyelia, a disorder in which cysts form along the spine, can cause scoliosis. These spinal abnormalities may play a larger role in causing some cases of scoliosis than previously thought.
• Familial dysautonomia, a rare disorder in Jewish children of Ashkenazi descent. (Only about 500 cases have been reported.)
• Stress fractures and hormonal abnormalities that affect bone growth in young, competitive athletes.
• Birth defects, including spina bifida (an open spinal cord) and myelomeningocele (a hernia of the central nervous system).
• Turner's syndrome, a genetic disease in females that affects physical and reproductive development.

 

Other diseases that can cause scoliosis are Marfan's syndrome, Aicardi syndrome, Friedreich ataxia, Albers-Schonberg disease, rheumatoid arthritis, Cushing's syndrome, and osteogenesis imperfecta.

 

Causes of Nonstructural Scoliosis: Nonstructural scoliosis is usually not a serious problem, since the curve is side to side. It can develop from a number of physical problems especially unequal leg length and hamstring spasms.

 

 

Managing Scoliosis:

 

The treatments for scoliosis are not always straightforward. For one, some patients do not treatment at all-- but careful observations. However when there is chance of progression or the curve is severe, treatment is warranted for which there are a number other options, including braces and different surgical procedures.

 

Which patients should be treated?

Usual guideline for treating scoliosis is to monitor the condition if the curve is less than 20 degrees and to consider treating curves greater than 25 degrees or those that progress by 10 degrees while being monitored. Some factors that impact the decision whether to operate the patient or observe for further progression are:

Age and gender:. In general, the older the child the less likely the curve will progress. Scoliosis in a child under 10, for example, is more likely to progress than scoliosis in an adolescent. Girls have a higher risk for progression than boys and also are more likely to perceive the cosmetic deformity, hence the decision to operate is more frequent in this group.

Location of the Curvature. Thoracic curves, those in the upper spine, are more likely to progress than thoracolumbar curves or lumbar curves, those of the middle to lower spine.

Severity of the Curvature. The higher the degree of curvature the more likely the chance of progression and the more likely the lungs will be affected. The curve greater than 45 degrees are more likely to get operated. The curve between 30 and 45 needs to be treated with conservative measures like brace and carefully monitored.

 

Monitoring progression:

 Progression is defined as two sequential x-rays showing more than 5o of change. Not all curves progress. The larger the curve at presentation the more likely it is to progress.

Most likely to progress: 

• Female sex - Incidence of mild scoliosis relatively equal but larger curves more common in females
• Young age at Diagnosis - Significant if chronological and physiological age consistent. If so, risk of progressing 10o or more is 3 times greater under age 12
• Skeletally immature - Risser < 2 - Risk at or before Risser 2 - 50%,  Risk after Risser 2 - <20%
• Sexually immature (premenarche) 
• Significant apical rotation on X Ray.
• Single thoracic curve 
• Large curve
• Cobb angle > 50o
• RVAD > 30o

Growth potential are also evaluated by a number of factors-  Historical, Age, Menarche, Growth spurt (outgrowing shoes and clothes), Height, Tanner's sign (breasts and pubic hair), Risser stage, Hand X-rays  .

 

A rough guideline for treating Scoliosis

	rapid growth	decreased growth
<20o	observation	observation or discharge
20-30o	observation	observation/brace if progressive
30-45o	brace	observation
>45o	surgical	surgical or observation

 

 

Untreated scoliosis can lead to:

• Back pain, which is unrelated to magnitude of curve. Usually not a significant problem 
• Cardiopulmonary dysfunction - Affected in thoracic curves. Inverse correlation between magnitude of curve and FVC. May develop restrictive lung disease. May lead to Respiratory failure, Cor pulmonale and right heart failure. Respiratory function is reduced by: Nil with curve < 60o; 1/3 with curve 60-100o; 1/2 with curve > 100o; Cor pulmonale occurs In 40s and 50s if curve > 80o; Problems more severe with early-onset deformities. Affects development of lungs
• Mortality - Only increased if curve >100o 
• Cosmesis - Appearance is major concern in most patients. Psychosocial effects in adolescents common.

 

 

Non Surgical Measures (conservative Management) in treating Scoliosis:

 

Exercise: Stretching exercises may be beneficial in children whose scoliosis is due to uneven leg lengths or a shortened tendon. ASCO Scoliosis Treatment Method is a Russian approach that consists of isometric and stretching exercises, vibration, spinal manipulation, and electrical muscle stimulation. Breathing exercises may help improve lung function in children with scoliosis and signs of lung problems.

 

Airway Ventilation at Night: Some studies have investigated the use of airways systems, such as nasal continuous positive airflow pressure, for patients with severe scoliosis and reduced lung capacity. Such systems are used during the night to force air into the upper airways and into the lungs. In one study, the use of these devices reduced hospitalization and improved lung function, shortness of breath, and fatigue. Such systems are used in the treatment of sleep apnea, a common sleep disorder.

 

Braces: A brace is often used to prevent further progression of moderate curves of (24 to 40 degrees). It is important to note that a brace will almost never reverse an existing curve and is only used to stop progression. Results vary widely depending on the length of time the brace is worn, the type of brace, and the severity of the curve.Wearing the brace for the prescribed time is difficult but is essential for any success. A team approach, with several health professionals involved, is beneficial and often necessary to support the patient through the bracing process. An orthopedic surgeon interprets the x-rays, assesses the potential progression of the scoliosis, and plans the treatment with the patient and family. If a brace is used, an orthotist measures and fits the patient with the device. A physical therapist tailors an exercise program best suited for the patient. A nurse may also get involved to coordinate the treatment plans and provide physical and emotional support.

Types of Braces:

 

Milwaukee Brace: Developed in 1945 by Blount and Schmidt. Standard orthosis for adolescent thoracic idiopathic scoliosis. It comprises a Pelvic girdle that reduces lumbar lordosis, two posterior uprights and one anterior upright. Neck ring with throat mould anteriorly and two occipital pads posteriorly. Was distraction device in past & caused significant problems with dentition. L-shaped thoracic pad that pushes at apex on convexity. Lumbar pad that similarly pushes at convexity. Provides passive correction by pressure on convex side and active correction by muscle contraction pulling body away from pads. Patient not weaned into brace. Seen after 2-3 weeks for adjustment, Then seen every 3-6 months. Brace adjusted. X-ray taken to assess response, in brace, to assess progression. Brace worn 23 hours a day. Allowed out to play sport. If curve progresses beyond 45o, surgery indicated. Weaning commenced once skeletal maturity reached.

 

Underarm orthoses - Thoracolumbar spinal orthosis (TLSO) [Boston]- If apex of curve below T8 - Made from thermoplastic material, from cast of patient in corrected position. Worn and weaned as for Milwaukee brace. 

 

Exercise and Physical Therapy While Wearing Braces

For children who require braces, an exercise program helps boost well being, improves compliance with treatment, and keeps muscles in tone so that the transition period after brace removal is easier.

An exercise and physical therapy program is important to maintain or achieve the following:

Chest mobility.

Proper breathing. In one study, young girls who wore the Boston brace and performed aerobic exercises for 30 minutes four times a week experienced improved lung function, whereas lung function declined in girls who did not exercise.

Muscle strength (especially in the abdominal muscles).

Flexibility in the spine. One small study showed that patients who performed exercises improving flexibility in the torso experienced less spinal twisting and had improved curvature.

Correct posture. Practicing correct posture, especially in front of a mirror, is an extremely important part of any physical therapy program. A patient who is accustomed to a curved spine may have the sensation of being crooked when first taught to properly align the spine. Practicing in front of a mirror provides a reality check.

Patients must also be taught to conduct daily activities while wearing the brace. Patients tend to comply with physical therapy in the period when the brace is first being used. They typically stop exercising when they have gotten used to the brace, however, and resume exercising only near the time the brace is being removed. It should be noted that patients who don't stay with the program throughout the duration of brace use experience a weakening in the back at the time of removal.

 

Surgical Intervention in Scoliosis:

 

Indications

Curve > 40-45o with documented progression (Special considerations with Double curve Often balances itself out. Does not progress unless > 60o )

Low lumbar curve

Adolescent or young adult

Idiopathic thoracic curve

 

Rationale

Correction of cosmetic defect 

Prevention of respiratory insufficiency

 

Goals

Reduction of rib hump 

Correction of rotation 

Achievement of rigid fixation to obtain solid fusion

 

Surgeries:

 

Fusion: All scoliosis operations involve fusing the vertebrae. The fusion procedure generally is as follows:

The surgeon first slices flaps to expose the backs of the vertebrae that lie along the curve.

The surgeon then removes the processes, the bony outgrowths along the vertebrae that allow the spine to twist and bend. The surgeon lays matchstick-sized bone grafts vertically across the exposed surface of each vertebra, being careful that they touch adjoining vertebrae. The flaps are then folded back to their original position, covering the bone grafts. These grafts will regenerate, grow into the bone, and fuse the vertebrae together.

Graft Materials. Bone grafts are taken from the patient's hip, ribs, spine, or other bones (called autografts). This is the best quality bone. However, because autografts are taken directly from the scoliosis patient, the operation is longer and the patient experiences more pain afterward. Researchers are also investigating allografts, which are bone grafts taken from another person or a cadaver. This would reduce the pain and duration of the operation. Allografts, however, pose an increased risk for infection from the donor. Longer-term studies are needed to determine the seriousness of this risk.

Healing. The healed fusions harden in a straightened position to prevent further curvature, leaving the rest of the spine flexible. It takes about three months for the vertebrae to fuse substantially, although one to two years are required before fusion is complete. Fusion stops growth in the spine, but most growth occurs in the long bones of the body (such as in the legs), anyway. Patients, then, will most likely gain height from both growth in the legs and from the straighter spine. Patients make walk at slightly slower pace after fusion, but balance may improve, and sports activities are not restricted after the procedure.

 

Instrumentation

 

Harrington Procedure. Until ten years ago, the standard instruments used in fusion procedures were those of the Harrington procedure, first developed in the 1960s:

To support the fusion of the vertebrae, the surgeon uses a steel rod, extending from the bottom to the top of the curve. (More than one rod may be used depending on the type of curve and whether kyphosis is present)

The rod is attached by hooks that are suspended from pegs inserted into the bone.

Similar to changing a tire, the steel rod is jacked up and then locked into place to support the spine securely. The surgeon is then ready to fuse the vertebrae together.

After this operation, patients are required to wear a full body cast and lie in bed for three to six months until fusion is complete enough to stabilize the spine.

After one to two years, the steel rod is not really necessary, but it is almost always left in place unless infection or other complications occur.

The Harrington procedure is very difficult to undergo, particularly for young people, and although the operation can achieve a correction of the curve of over 50%, studies have reported a loss in this correction of between 10% to 25% over time. The procedure does not correct the rotation of the spine and, therefore, does not improve an existing rib hump that was caused by the rotation. The operation does not interfere with normal pregnancies and deliveries later in life.

Certain complications may occur from this procedure:

About 40% of Harrington patients have a condition called the flat back syndrome, because the procedure eliminates normal lordosis (the inward curving of the lower back). Flat back syndrome from the Harrington procedure does not cause any immediate pain. In later years, however, the disks may collapse below the fusion, making it difficult to stand erect, and the condition can cause significant pain and emotional distress.

Studies have reported that five to seven years after their surgery, between a fifth and a third of patients who had the Harrington procedure experienced low back pain. (In one study, only 3% had experienced back pain before surgery.) In such cases, however, the pain was not severe enough to interfere with normal activities and did not require additional surgery.

In children younger than 11 whose skeleton is immature and who have the Harrington procedure, there is a fairly high risk for a specific curve progression called the crankshaft phenomenon. This condition occurs after the procedure when the front of the fused spine continues to grow. The spine cannot grow longer, so it twists and develops a curvature. In one study that followed patients for between five and 16 years, crankshaft curve progression was moderate, however, with the Cobb angle averaging 9 degrees and rotation averaging 7 degrees.

 

Cotrel-Dubousset Procedure. The Cotrel-Dubousset procedure not only corrects the curve but may also help to correct rotation, and it does not cause flat back syndrome.

With this procedure, parallel rods are cross-linked for better stability in holding the fused vertebrae. Improvement in correction averaged 66% in one study, with a later correction loss reported to be 5%. (Other studies have reported loss of curvature correction at less than 2%.) Over 95% of patients reported the results to be good or very good (only 86% of patients who had the Harrington procedure experienced the same levels of satisfaction). Patients often go home in five days and may be back in school in three weeks.

Complication rates are similar to the Harrington procedure, but there are some differences:

Operation time and blood loss are greater than with the Harrington procedure.

Cotrel-Dubousset and other procedures that are designed to reverse the rotation of the spine have less risk for flat back syndrome but they have a higher risk for spinal imbalance than the Harrington procedure.

Failure rates after 10 years are about 25%, which is very high. Experts hope that the advances in current scoliosis procedures will help reduce the long-term adverse effects.

 

The Texas Scottish-Rite Hospital (TSRH) Instrumentation. The Texas Scottish-Rite Hospital (TSRH) instrumentation is similar to the Cotrel-Dubousset procedure in that it uses parallel rods and other devices that reverse rotation as well as improve curvature. TSRH, however, uses smooth rods and hooks that are designed to make removal or adjustment easier later on if complications arise. Complications are similar to the Cotrel-Dubousset procedure.

 

Other Instrumentation Systems: Other instrumentation procedures have refined the hardware used in the Harrington and Cotrel-Dubousset operations.

Wisconsin segmental spine instrumentation (WSSI) may also be effective. It is as safe as the Harrington rod and nearly as strong as the Luque instrumentation.

Luque instrumentation was developed to help maintain normal lordosis and experts hoped that bracing would not be needed afterward with this device. A number of studies showed, however, that without braces, correction was lost after this operation, and there also may be a higher risk for spinal cord injury than with standard procedures. Luque instrumentation is used primarily in people whose scoliosis is due to problems of nerves and muscles, such as in children with cerebral palsy.

 

The Dorsal Dynamic Spondylodesis (DDS) system and Dynessys is a semirigid system that allows for greater flexibility of the spine.

 

Instrumentation for Anterior Approach. Specific hardware is needed for the anterior approach, in which the surgeon performs the operation by opening the chest wall. Halm-Zielke instrumentation, for example, uses TSRH instrumentation with bone grafts constructed from ribs to prop open the spaces between the discs. It allows true three-dimensional curve correction. However, it does not solve specific problems with this approach, which are higher risks for kyphosis (an outward curve) and pseudoarthrosis (a false joint at the fusion site). Variants using two rod systems, fusion cages, or other instruments appear to improve this procedure.

 

The Surgical Approach

 

Posterior Approach (Through the Back). Generally, surgeons have used a posterior approach for scoliosis, which reaches the surgical area by opening the back of the patient. It has been the gold standard for decades and is generally used with Harrington instrumentation. The approach has advantages and disadvantages.

Advantages of the Posterior Approach. Surgeons are familiar with it and so fusion rates are excellent, curve correction is good, and it has few complications.

Disadvantages of the Posterior Approach. There is a risk for the crankshaft phenomenon (a worsening of the curve) later on in preadolescent children. (Newer posterior instrumentation, such as the Isola instrumentation, may prevent this occurrence.) The posterior approach also does not always correct hypokyphosis (the loss of normal outward curvature) in the thoracic (upper) spine. The procedure is not always effective for curves in the thoracolumbar region (the region where the upper and lower spine meet) and may even cause spinal abnormalities there.

 

Anterior Approach (Through the Chest Wall). Increasingly surgeons are using the anterior approach, in which the surgeon performs the operation by opening the chest wall (called a thoracotomy). With the anterior approach, the surgeon makes an incision in the chest, deflates the lung, and removes a rib in order to reach the spine. This rib can be used during the operation as a strut to support the spine. It also may be repositioned within the patient until it is used for bone grafting during fusion.

This approach also has its advantages and disadvantages:

Advantages of the Anterior Approach. Because the frontal approach allows the procedure to be performed higher up in the spine than with standard procedures, the patient may have a lower risk for lower-back injury later on. In addition, transfusion rates are much lower with the anterior approach. With increasing experience, the anterior approach is as effective as the posterior approaches.

Disadvantages of the Anterior Approach. It is a more recent procedure than the posterior approach, and in inexperienced surgeons there is a higher risk for complications than in the more standard posterior approach. One study noted poorer lung function two years after surgery than with the posterior approach, possible because the wide chest incision produces impairs the chest muscles, which can affect lung function afterward. Anterior instrumentation poses a risk for hyperkyphosis (exaggerated outward curvature) and a higher risk for pseudoarthrosis, a painful condition in which a false joint develops at the fusion site. Hardware failure rates may also be higher with the anterior than posterior approach. Increasing experience and newer hardware designs are reducing many of these problems.

 

The Combined Anterior-Posterior Approach. The combination approach uses an anterior approach first, which allows better correction of the problems. The fusion part of the operation is done with the posterior approach. This is a very long and complex procedure. It appears to be safe, however, and is proving to be useful, even in very young patients, for preventing the crankshaft phenomenon. It may also be used to correct large rigid curves and for specific severe curves in the thoracic spine.

 

Minimal Access Spinal Approach. Minimal access spinal technologies use a few small incisions and so are far less invasive than the standard so-called open approaches that require wide cuts. The technique uses endoscopy, in which the surgeon makes small incisions and inserts tubes that contain tiny instruments and cameras through the incisions in order to view and execute the procedure. In most cases, the procedure is done in two stages:

First, an anterior approach is employed to remove disk material and loosen the spine.

Secondly, a posterior approach is made for fusion and instrumentation.

Recovery after surgery is rapid. Most patients are out of bed two days after surgery.

Corrections are reaching 68% in some patients. There is a much more cosmetically appealing result (fewer and smaller scars) with endoscopy, and an easier recovery than with the more invasive approaches.

The endoscopic procedure for scoliosis is complicated and few surgeons can perform it yet. Currently, it is generally used only for single curves in the upper back or for patients with a curve in the upper back and a curve in the lower back that compensates for it. Some surgeons are now able to operate on areas below the diaphragm, including the lumbar spine. The patients must still wear a brace for three months afterward. Long-term studies are required to determine how outcomes compare to standard procedures.

 

Possible Complications of Surgical Procedures:

Early complications

• Neurological injury during surgery - Incidence is 1% in adolescents and 2% in adults. May be minimised with spinal cord monitoring. Wake-up test often used
• Blood loss - Risk of transmission of disease with transfusion. Techniques of conservation used = Autologous donation, Hypotensive anaesthesia, Autotransfusion
• Wound infection - Prophylactic antibiotics indicated
• Pneumothorax - Occurs during subperiosteal spine exposure, esp. Area between adjacent thoracic transverse processes on concave side
• Dural tear - During ligamentum flavum removal or hook or wire insertion
• Abnormal sagittal alignment - Inadvertent 'flat-back'
• Incorrect fusion levels - From incorrect preoperative choice or from incorrect intraoperative placement
• Inappropriate ADH secretion - Postoperative SIADH - Decreased urinary output, decreased serum osmolality and increased urine osmolality. If not diagnosed, iatrogenic fluid overload and even death may occur.

 

Late complications

• Pseudarthrosis - Occurs in about 1%, 5% with fusion to sacrum. Solid fusion should occur by 6 months
• Rod or wire breakage - Due to pseudarthrosis or fatigue failure.  If pain persists or correction lost, fixation must be removed
• Back pain - Appears to be due to Fusion below L4 , Loss of lumbar lordosis 

 

Other Complications: Other problems that can occur include, but are not limited to, the following:

• Dislodgment of hooks or fracture of a fused vertebra.
• Gallstones.
• Pancreatitis (inflammation of the pancreas). Among adolescents, this complication tends to occur more often among those who are older or who have a lower body mass index.
• Intestinal obstruction.
• Serious postoperative complications that involve the lungs and circulation. These complications are highest in children whose scoliosis is due to neuromuscular problems, such as spina bifida, cerebral palsy, or muscular dystrophy. Such children may need to be managed in an adult intensive care unit.

 

Postoperative Therapy: Breathing and coughing exercises to rid the lungs of congestion must be performed shortly after the procedure and continued through the recovery process. The patient is usually able to sit up the day after the operation, and most patients can move on their own within a week. A brace may be necessary, depending on the procedure. With the anterior approach in the upper back, patients may have some trouble with activities involving the arms and hands--such as tying shoes and cutting food. In one study, however, occupational therapy using stretching and strengthening exercises allowed for full resumption of daily activities, including dressing, bathing, and grooming, within three months. Patients are often concerned that surgery will stiffen their backs, but most cases of scoliosis affect the upper back, which has only limited movement, so that patients do not notice much difference. It may take a year or more for muscle strength to return. In some cases, the operation cannot completely correct the curve, and one leg may be shorter than the other. Heel lifts may be used in this case.