Scoliosis

• Abnormal sideways curvature of the spine in an S or C shape resulting in uneven shoulders and hips
• Deformity of spine in 3 places – rotation, lateral bending, lordosis

Epidemiology

• Age of onset is usually 10-15 years
• More common in females

Etiology

• Combination of genetic and environmental factors
• 65% of cases are idiopathic, 15% are congenital, 10% are secondary to other conditions

Pathology

• The main pathology is the lateral curvature of the spine – called the primary curve
• There may be compensatory curvature above or below the primary curve – called the secondary curves
• Lateral curvature is due to rotation of the vertebrae
  • When thoracic spine is affected, rotation leads to prominence of the rib cage on the convex side, giving the appearance of a ‘rib hump’
  • Lumbar spine can also be affected
• Risk factors for curve progression
  • Female sex
  • Young age
  • Premenarche
  • Skeletal immaturity – assessed by Risser classification
  • Cobb’s angle >50^o
  • Progression >5^o over two consecutive X-rays

Classification

• Idiopathic scoliosis – most common. Associated with CHD7 and MATN1 genes
  • Infantile – below 3 years
  • Juvenile – 3-10 years
  • Adolescent – over 10 years
• Congenital scoliosis
  • Due to failure of normal vertebral development during 4-6^th gestational week
• Neurogenic scoliosis
  • Secondary to neuromuscular conditions – muscular dystrophy, poliomyelitis, celebral palsy
• Syndromic
  • Associated with other syndromes –  Ehlers-Danlos syndrome , fragile X, Marfan’s syndrome Prader-Willi etc

Clinical features

• Idiopathic scoliosis most commonly shows visible deformity but no pain
• Pain in back, shoulders, neck and ribs
• Respiratory problems
• Rib prominence/hump – in thoracic scoliosis
• Uneven leg length
• Café-au-lait spots – in neurofibromatosis
• Limited mobility
• Slow reflexes

Diagnosis

Physical exam

• Adams forward bending test – ask patient to bend forward at the waist and examiner looks at the level of the scapulae from behind the patient

X-ray

• Measurement of Cobb’s angle
  • Two lines are drawn perpendicular between uppermost and lowest vertebrae involved in the primary curvature
  • The angle between the intersecting lines is Cobb’s angle
• Interpretation of Cobb’s angle
  • <10^o = non-scoliosis
  • 10-30^o = mild
  • 30-45^o = moderate
  • >45^o = severe

MRI 

• To rule out intraspinal anomalies
• Indications
  • Atypical curve pattern
  • Rapid progression
  • Neurologic symptoms
  • Foot deformities
  • Asymmetric abdominal reflexes

Treatment

• Based on the Cobb angle
• Observation – <25^o
• Bracing – 25-45^o
  • Aims to stop progression, rather than correct deformity
  • Recommended for between 16-23 hours a day until skeletal maturity
  • Obesity and non-compliance reduce outcomes
• Surgery – >45^o
  • Posterior spinal  fusion – gold standard for thoracic and double major curves
  • Anterior spinal fusion – for thoracolumbar and lumbar curves
  • Anterior and posterior spinal fusion – for Cobb’s angle >75^o

Complications

• Neurologic injury
• Infection
• Flat back syndrome
• Superior Mesenteric Artery syndrome