Monday, January 26, 2009

SCOLIOSIS



SCOLIOSIS

Nam H. Tran, MD
November 9, 1997
Stanford Medical Center



I. HISTORICAL PERSPECTIVE:
Spinal deformities afflicted early man as documented in cave drawings.
“Skoliosis” is used by Hippocrates to denote any curvature of the spine. Many forms of treatment were attempted.
Paul Aegina tried bandaging as a form of bracing in the 7th century.
1914: first fusion performed by Russell Hibbs
1946: Milwaukee brace was designed by Blount and Schmidt.

II. DEFINTION:
Scoliosis: any lateral curvature of the spine.
Scoliosis can be further described as:
Right or Left: sidedness defined by the side of convexity of the curve, ie, right scoliosis has the convex side toward the right.
Cervical, cervicothoracic, thoracic, thoracolumbar, lumbar.
Single vs Compound: single has one sided spinal deviation whereas compound has both right and left spinal deviations.
Primary vs Secondary (compensatory): primary describes the initial curve that can later be compensated for by a curve in the other direction (secondary scoliosis).
Major vs Minor: major curve denotes the greatest curve which often accompanied by a minor curve, usually a compensatory curve(s) in the other direction above and below the major curve. Sometimes, the compensatory curve is as large as the major curve; in which case, this is called a double major curve.
Nonstructural vs Structural: nonstructural curve will be corrected with lateral bending toward the convex side. In structural scoliosis, the curve remains with side bending.


III. ETIOLOGY:

IV. PATHOLOGY:
The vertebra turn toward the convex side and spinous processes rotate toward the concave side in the area of the major curve.
As the vertebra rotate, they push the ribs on the convex side posteriorly and at the same time, crowd the ribs on the concave side together as well as push them anteriorly. The posterior displaced ribs cause the characteristic hump in the back with forward flexion. Young girls with scoliosis would often complain of unequal breasts. This is due to recess of the chest wall on the convex side of the curve.
Disc space is narrower on the concave side and wider on the convex side.
The vertebra may become wedged on the concave side in serve cases. The lamina and pedicles are also shorter.
Vertebral canal is narrower on the concave side. Spinal cord compression is rare even in serve cases.
Physiological changes include:
Decrease in lung vital capacity due to a compressed intrathoracic cavity on the convex side.
With left scoliosis, the heart is displaced downward; and in conjunction with intrapulmonary obstruction, this can result in right cardiac hypertrophy.

V. EVALUATION:

A. HISTORY:
B. Chronological age
C. Age at recognition of deformity. The longer the muscle imbalance, the more the distortion.
D. Impression of the rate of progression
E. Associated symptoms: pain, fatigue, cardiopulmonary symptoms. History of night pain resolved with ASA is concerning for osteoid osteoma. Back pain in young children can be due to spondylosis or spondylolisthesis and disc herniation.
F. Developmental factors: rate of growth, appearance of 2nd sexual characteristics (menarche). Rapid scoliotic curve changes occurs during rapid spine growth period. Progression usually halts or is much slower at skeletal maturity.
G. Genetic factors: racial origin. Infantile idiopathic scoliosis is more common in Britain and Europe.

H. PHYSICAL EXAMINATION:
I. GENRAL EXAMINATION should include the following:
J. Cardiopulmonary function is compromised in extreme thoracic curve, paralytic curve, and congenital scoliosis. Pulmonary and cardiac studies should be performed. Cardiac defects are common in Marfan’s syndrome.
K. Developmental status and Secondary Sexual Characteristics can be assessed by noting the patient’s height compared with parents and siblings. This can be significant in predicting future growth. Dentition maturity is also helpful.
L. Underlying causes: Skin manifestations, ie, café aulait spots are suggestive of neurofibromatosis, and hairy back patches are clues to spinal dysraphism (spinal bifida).
M. Genitourinary development and status can be affected in congenital conditions.
N. EXAMINATION OF DEFORMITY:
O. Standing position: From behind the patient, begin with an evaluation of truncal alignment noting for overall balance and torso displacement.. Asymmetry can be easily noted as evident by asymmetry of the shoulder height, infolding of skin and prominence of the iliac crest on the concave side, shifting of the thoracic cage and prominence of the anterior chest on the convex side (due to anterior rotation on the convex side). Drop a plumb line from the occiput which should line up with the gluteal cleft. Be aware that in a compensated double major curves, the alignment may be normal.
P. Symmetry of Shoulder Girdle: neck shoulder angle distortion is due to trapezius asymmetry from cervical or high thoracic curves.
Q. Assessment of specific curves:
R. Types of curves are noted, ie, left vs right, C-T-L or combination.
S. Flexibility vs rigidity of the curves can be assessed by side bending or head distraction. This is important for planing surgery.
T. Degree of rotation is assessed in the bent postion by noting prominences in the thoracic and lumbar areas.
U. Pelvic obliquity and stability: Pelvic obliquity can be non-structural due to habits or structural due to leg length discrepancy or contracture of muscle groups.
V. Neurologic examination includes reflexes, sensation, motor strength to ensure that there are no deficits or deterioration of baseline deficits. Isolated decreased vibratory sensation is frequent in idiopathic scoliosis and does not warrant further work up.
W. IMAGING ASSESSMENT:
A single standing P-A film taken from occiput to sacrum is adequate. Radiographic imaging may not be needed in children with very mild curves detected on routine school screening examination. These children can be followed by physical examination with scoliometer. If there is a significant change over the previous 6 months or if there is a severe rib rotation, Xray is then warranted.
In general, young patients with mild scoliosis can be safely seen in follow up and Xray done every 6-9 months. For faster progressive curves, Xray every 3 months is recommended. In adolescents, a progression of 1 degree/month is normal, where as a significant progression is 3-5 degree/month.
Spot lateral view is useful to assess for spondylolisthesis and spondylosis which can occur in 30-35% of children with Scheuermann’s disease (occurs in 5% of idiopathic scoliosis which is the same as that of the general population).
Side bending Xray is useful to determine the rigidity of scoliosis, an important consideration for surgical planning. It will also help to delineate structural from non structural scoliosis (non-structural curves with uncoil with bending to the convex side).
4. CURVE MEASUREMENT:
5. Cobb method: This method relies on the accuracy of identifying the vertebra at the upper and lower end of the curve. These end vertebrae are those with maximal tilt toward the concave side. Horizontal lines are then drawn at the superior border of the superior end vertebrae and at the inferior border of the inferior end vertebrae. Perpendicular lines to these two horizontal lines will intersect. The angle formed is the Cobb angle, the degree of scoliosis. The advantage of the Cobb method is that it has high inter-rater reliability.
6. Risser-Ferguson method: Straight lines are drawn from the middle of the end vertebra to the middle of the vertebrae at the apex of the curve. This method is not frequently used.
7. ROTATION ASSESSMENT: Rotation is an inherent structural change in scoliosis. It correlates with the degree of resistance to corrective therapy. Rotation can be recorded in two ways:
8. Displacement of Pedicles: On A-P view, one pedicle rotates toward the midline and the other rotates to the lateral border of the vertebra.
(+) pedicle slightly toward midline
(++) pedicle 2/3 toward midline
(+++) pedicle at midline
(++++) pedicle moves beyond midline
Note: rotation is toward the concave side.
b) Displacement of Spinous Processes: (+) rotation is a displacement of one width of the spinous process from the midline, and so forth. This method is not accurate since the spinous processes are often deformed (bent toward the concave side).
c) SKELETAL MATURITY: Scoliotic progression slows significantly at full maturity. It is therefore essential to know when skeletal growth is complete to plan for therapy, follow up frequency, and cessation of therapy. In general, girls mature at about 16 ½ years old, and boys about age of 18. Reviewing the radiographs can reasonably predict skeletal maturity:
Left hand and wrist films for comparison with Greulich and Pyle atlas.
Excursion of the iliac crest described by Risser. Ossification of the crest starts laterally and meets with the SI junction as well as fuses with the ilium at full maturity.
Growth plate of the vertebra form a solid union at full maturation. At 6-8 years of age in girls (7-9 years old in boys), a calcific ring develops at the superior and inferior aspect of the vertebra. This ring gradually fuses with the vertebral body at the age of 14-15. Complete fusion occurs at age 21-25.

VI. PROGNOSIS:

It is important to know the natural course of the curve to determine the appropriate course of management. At the end of longitudinal growth, significant scoliotic progression usually ends. However, the gravest error that a treating physician can make is to assume that curve progression halts. In some cases, scoliosis continues to progress approximately 1 to 2 degrees per year through adult life causing significant disability at old age. These include patients with significant curves of more than 40 degrees, poor muscle tone, and women near menopause with osteoporosis. Adults with curves less than 30 degrees usually do not progress.

Some authors feel that childhood scoliosis has a strong genetic inheritance. As such, the scoliotic curve will progress to a predetermined severity unless the course is altered by intervention with bracing, exercise, and/or surgery.

In general, the following rules apply:
a) Thoracic curves causes more deformity and disability.
b) The earlier the age of onset, the greater the deformity and disability later in life.
c) Some prognostic signs of xray for active progression of scoliosis are: osteopenia of the vertebra near the apex of the curve, narrowed intervertebral disc space, and wedging of the apical vertebra.

VII. IDIOPATHIC SCOLIOSIS:

A. GENERAL:
Accounts for 70% of all scoliosis.
Overall incidence is equal for boys and girls.
Progression is much more severe in girls, and seven times more frequent.

B. ETIOLOGY:
C. Genetic: Probably sex linked inheritance with variable penetrance and expressivity. If a person with scoliosis has children, one of three offspring will probably develop scoliosis.
D. Nervous System Dysfunction: It is believed that brainstem dysfunction can cause scoliosis. Also lesions in the posterior column can result in postural imbalance. The dysfunction of the balancing mechanism is felt to result in scoliosis. Others feels that it is due to “lack of synchronization of thegrowth of the neuro-axis and the neural canal”.
E. Nutrition: Poor nutrition may cause scoliosis as suggested by animal research data.
F. In conclusion: Cause is still not known.

C. CLASSIFICATION: Idiopathic scoliosis occurs at three separate developmental time periods with different characteristic deformities and prognosis.
D. Infantile: Occurs between birth and 3 years of age. Usually noticed in the first year of life. More common in boys particularly from England. Left thoracic curve occurs more common, and often resolves spontaneously. Few patients will have progressive curves which can be quite severe requiring early bracing and even surgery.
E. Juvenile: Occurs between 4-10 years of age. Incidence is equal for boys and girls. Most curves are right thoracic. Curves are progressive in nature and need close follow up.
F. Adolescent: Usually diagnosed at the age of 10. Most curves are right thoracic and thoracolumbar. Curves have a strong tendency to progress during adolescent growth spurt. Extremely active, athletic teenage girls with delayed menses are most of risk for curve progression.

D. CURVE PATTERN:
E. Right thoracic curves are most common. The can develop rapidly and must be treated early or severe cosmetic deformity. Cardiopulmonary compromise will ensue when curves reach 60 degree.
F. Thoracolumbar curves are also common. They are usually not as deforming.
G. Lumbar major curves are less common. Most (65%) are left lumbar curves. They are not deforming but can lead to disabling back pain in later life and during pregnancy.

H. NATURAL HISTORY:
Lonstein & Carlson (1984): 729 patients with idiopathic scoliosis of less than 30 degrees were followed without bracing. Likelihood of progression of a thoracic scoliosis was compared with curve magnitude and Risser sign.

Scoliosis Risser Chance of Progression

<19 0 or 1 22%
<19 2,3 or 4 1.6%
20-29 0-1 68%
20-29 2,3 or 4 22%

F. TREATMENT:
G. School screening: Best treatment is early detection. School screening should start in the fifth grade (age 10-11), and every 6 to 9 months thereafter. Screening can be done quickly by having the child bend from the waist with arms hang freely. If scoliosis is detected in a child, all siblings should be screened due to the hereditary nature of the condition. The downside with school screening is that it can pick up extremely mild curves that do not progress, and can cause needless anxiety in parents.
H. Exercises: It does not prevent or cure scoliosis and is not a substitute for bracing or surgery.
I. Spinal bracing:
J. In 1945, Blount developed the Milwaukee brace, which has undergone several modification to reduce weight and bulkiness. Bracing was enthusiastically endorsed in the 1960’s. Sentiment shifted in the 1980’s to the extreme that Professor Robert Dickson of Leeds, England, stated that there was no place for bracing in the treatment of idiopathic scoliosis. Since then, the pendulum has swung back. Several good studies looking at the natural progression of scoliosis and bracing for each specific curve patterns and age groups clearly demonstrated the effectiveness of bracing in preventing the progression of scoliosis.
K. Based on study on the natural history by Lonstein, it is obvious that bracing is not needed for curve less than 19 with a Risser of 2,3, or 4. In contrast, a child with a Risser 0 or 1 with a curve between 20-29 degrees is at a significant risk of curve progression.
L. Three studies that set the standards of bracing for this high risk group:
Lonstein and Winter: 1020 patients treated with Milwaukee brace. Those patients with thoracic curves of 20-29 degrees and Risser 0-1, only 40% showed progression at the end of bracing (vs 68% if not braced).
Bassett: 71 patients with curves 20-29 degrees and Risser 0-1. Only 36% of those with thoracic curves progressed.
Durand: 477 patients. At 2-5 year follow up, only 21% of patients had progressed.
d) In summary:
Milwaukee brace for thoracic curves and TLSO for lumbar or thoracolumbar curves.
No bracing needed for curves less than 20 degrees.
Curves of 20-29 degrees need bracing when 2 or more years of growth remain or if there is evidence of progression.
Curves or 30-39 degrees should be braced at the first visit if growth remain.
No bracing needed for patients with Risser 4 or 5.
Brace should be worn 20-22 hours per day and taken off for hygiene and strengthening exercises.
Patients should be seen on a monthly basis for brace adjustment with Xray taken every 6 months.
Weaning off brace: When the child is more mature and the curve holds its position, the child is allow more time out of the brace. The weaning period takes about 2-3 years until the age of 15 in girls and 16 ½ in boys.
4) Surgical Treatment:
5) Indications:
Adolescents with curve more than 45 degrees.
Relentless curve progression
Major curve progression in spite of bracing
Inability to wean the patient from the brace
Significant thoracic and lumbar pain
Progressive loss of pulmonary function.
Emotional or psychological inability to accept the brace.
Severe cosmetic changes in the shoulder and trunk.
b) Goals:
To achieve solid fusion
To stabilize the curve with a compensated trunk both in the frontal and sagittal planes
To correct the curves (though this is not as important)
c) Surgical Techniques:
Fusion can be done through the anterior or posterior approach. The posterior approach is preferred. In cases like myelomeningocele where posterior spinal elements are absent, then the anterior is approach is used..
The posterior approach was first performed in 1911. The techniques have changed somewhat with the introduction of spinal instrumentation in the past 40 years. But in general, the principles are as followed:
i) The outer cortex of the laminae and spinous processes are removed so that raw cancerous bone is exposed.
ii) Posterior facet joints are destroyed.
iii) Great quantity of iliac autografts are laid on the prepared bed.
iv) The fusion extends one vertebrae above the superior end vertebrae and two below the inferior end vertebrae.
v) A combination of Harrington instrumentation and are used to decrease rotation and increase internal stabilization of the spine. Intersegmental wires can be secured through the spinous processes (Drummon/Keene technique) or through the lamina of each vertebrae (Luque technique). The combination of rods and wires provides rigid fusion and is very effective in treating collapsing type scoliosis, especially in neuromuscular scoliosis.
vi) Post op care:
vii) Post op bracing is not necessary with the new technique of internal fixation. However, a low profile brace is recommended for several months to protect patients against accidents.
viii) Most patients can return to school or work within 2-3 weeks.
ix) Strenuous exercises are not recommended for the first few months. Light sports such as tennis can be resumed at 3-4 months.
x) At one year when fusion has mature, all forms of exercises can be resumed, though patient should avoid heavy contact sports.

VIII. CONGENITAL SCOLIOSIS:
A. Etiology: due to an insult to the zygote or embryo during early development
B. Associated conditions: 20% have urinary tract problems and 15% have cardiac anomalies.
C. Classification: Closed vs open
D. Open types are caused by myelomeningocele which can be severe.
E. Closed types can be classified according to etiology:
F. Partial unilateral failure of vertebral formation (wedge vertebrae)
G. Complete unilateral failure of vertebral formation (hemivertebrae)
H. Unilateral failure of segmentation (congenital bar)
I. Bilateral failure of segmentation (block vertebrae)
J. Prognosis: Hemivertebrae and unilateral can cause severe curvature.
K. Treatment: In situ spinal fusion should be performed promptly for progressive curves.

L. OTHER CAUSES OF SCOLIOSIS:

M. NEUROMUSCULAR DISEASES:
Caused by neuropathic disorders like poliomyelitis or cerebral palsy secondary to muscle imbalance. The resultant curves are usually long C shape.
Static myopathic disorder like muscular dystrophy can develop collapsing scoliosis due to severe muscle weakness and imbalance. A 10 degree curve can often become 90 degrees on sitting or standing.

A. NEUROFIBROMATOSIS:
First described by Kolliker in 1860, but von Recklinghausen coined the term in 1882.
Associated with peripheral nerves, causing cutaneous and subQ manifestations.
High incidence of kyphosis and scoliosis. Etiology ??? but may be due to neurofibromas enlargement in the foramina between vertebral bodies.
Spinal deformities must be treated aggressively with anterior and posterior fusion.

A. MESENCHYMAL DISORDERS:
Marfan’s syndrome, rhematoid arthritis (Still’s disease), and osteogenesis imperfecta can cause scoliosis.

A. TRAUMA:
Fracture causing wedging of the spine.
Tumor causing stunning of vertebral growth.
Radiation for tumor arresting vertebral growth plate
Burns or rib resection.






References:

1. Royo-Salvador MB.
[Platybasia, basilar groove, odontoid process and kinking of the
brainstem: a common etiology with idiopathic syringomyelia, scoliosis and
Chiari malformations].
Revista de Neurologia, 1996 Oct, 24(134):1241-50.

6. Worthington V; Shambaugh P.
Nutrition as an environmental factor in the etiology of idiopathic
scoliosis.
Journal of Manipulative and Physiological Therapeutics, 1993 Mar-Apr,
16(3):169-73.

4. Winter RB.
The pendulum has swung too far. Bracing for adolescent idiopathic
scoliosis in the 1990s.
Orthopedic Clinics of North America, 1994 Apr, 25(2):195-204.

5. Pinto WC
Common Sense in the Management of Adolescent Idiopathic Scoliosis, Orthopedic Clinics of North America, 1994 April, 25(2):215-223






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