4 – Spine deformities

Basics of spine

• Curvatures
  • Lordosis – concave (inward)
  • Kyphosis – convex (outward)
  • Scoliosis – deformity in all 3 planes (not just sideways)
    • Lateral curvature in the coronal plane
    • Lordotic deviation in the sagittal plane
    • Vertebral rotation in the horizontal plane
  • Normal:
    • Cervical lordosis
    • Thoracic kyphosis
    • Lumbar lordosis

Basics of scoliosis

• Scoliosis – deformity in all 3 planes (not just sideways)
  • Lateral curvature in the coronal plane
  • Lordotic deviation in the sagittal plane
  • Vertebral rotation in the horizontal plane
• Most patients with scoliosis have small curves without progression
• Scoliosis causes a characteristic “rib hump” when bending over
  • Due to the rotation of the vertebrae the ribs will be pushed posteriorly
• Scoliosis is a dynamic deformity – annual (or more frequent) follow-ups are mandatory until bony maturation
• Categorization of scoliosis based on onset
  • Congenital (due to vertebral malformations)
  • Early onset (< 9 years)
    • Infantile (< 3 years)
      • Boys > girls
      • 80% spontaneously resolve
    • Juvenile (3 – 9 years)
      • Boys = girls
  • Adolescent (11 – 18 years) (= adolescent idiopathic scoliosis, AIS)
    • Boys < girls (1:7)
  • Adult
    • Rare
    • Due to degenerative disease, trauma, etc.
• Categorization of scoliosis based on vertebral rotation
  • Structural scoliosis – with vertebral rotation
  • Functional scoliosis – without vertebral rotation
    • See topic 30
• Diagnosis
  • Scoliometer
    • = a tool which measures the angle of trunk rotation
  • Coronal balance
    • Patients with scoliosis will compensate in the coronal plane by laterally moving their head or pelvis
    • Computers measure the degree of compensation of scoliosis based on x-ray
    • If the straight line from C7 does not land between the buttocks, the scoliosis is decompensated to one side
    • During treatment the goal is to put the spine into normal coronal and sagittal balance
  • Sagittal balance
    • Patients with scoliosis will compensate in the sagittal plane by anteriorly or posteriorly moving their head or pelvis
    • Computers measure this as well
  • X-ray
    • Of full spine (base of skull to pelvis)
      • To check the pelvic compensation as well
    • AP and lateral views
    • While standing and while bending laterally
    • TRuGA (traction x-ray under general anaesthesia)
      • X-ray while the head and pelvis are pulled in opposite directions
      • Shows how rigid the curve is
  • MRI
    • Only if red flags (like unusual curve) are suspected
    • Can detect tethered cord, syringomyelia, dyasthematomyelia, Chiari malformation
    • If these conditions are not detected before scoliosis surgery paralysis or severe complications can develop
  • 3D CT
    • If congenital vertebral malformations are suspected
• How to measure scoliosis -> measure Cobb angle
  • Cobbs angle is the angle between the following two lines:
    • A line parallel to the superior endplate of the highest affected vertebra
    • A line parallel to the inferior endplate of the lowest affected vertebra
  • A Cobb angle of > 90 degrees has high risk of cardiac or respiratory disease, so surgery is always indicated
    • Depending on the type of scoliosis surgery may be indicated at smaller degrees too

18. Scheuermann’s Disease

• = Scheuermann kyphosis
• Epidemiology
  • Male > female (2:1)
  • Prevalence 4 – 8%
  • Starts around puberty
• Pathology
  • Avascular necrosis of the vertebral body apophysis
• Clinical features
  • Usually affects thoracic spine
  • Rigid, progressive, and painful hyperkyphosis
  • Kyphosis increases when bending forward
  • Subacute back pain
• Signs on X-ray
  • Regular hyperkyphosis (Cobb angle > 40 degrees)
  • Wedging of vertebral bodies
  • Irregular endplates
  • Schmorl herniation
  • Long and narrow vertebral bodies (compared to normal cube shape)
• Treatment
  • Cobb angle 40 – 70 degrees
    • Schroth therapy and Gschwend brace
  • Cobb angle 70 – 80 degrees
    • Surgery if pain is dominant
  • Cobb angle > 80 degrees
    • Surgery

30. Functional scoliosis, postural deformities

• Functional scoliosis = A structurally normal spine that appears to have a lateral curve
  • The spine appears scoliotic due to an underlying problem like:
    • Limb length discrepancy
    • Antalgic posture
      • Disc herniation
      • Sacroiliitis
      • Appendicitis
      • Etc.
    • Hysteriform scoliosis
      • Very rare
      • Some kind of psychosomatic problem in young females?
  • There is NO rotation of the vertebral bodies, unlike in structural (normal) scoliosis
    • -> No rib hump when bending over
    • -> Scoliosis disappears in supine position or when bending to the side
• Postural deformities
  • Normal posture of spine
    • Cervical lordosis
    • Thoracic kyphosis
    • Lumbar lordosis
    • Lumbosacral kyphosis
  • Postural deformities
    • Excessive thoracic kyphosis
    • Excessive lumbar lordosis
  • Treatment
    • By physiotherapy and exercise
    • Surgery not required

42. Scoliosis with known etiology, treatment of

• Structural scoliosis is secondary in 20% of cases
• Compared to idiopathic scoliosis, neuromuscular scoliosis involves
  • Pelvic deformities in addition to the spinal deformities
  • Risk of progression independent of growth (after skeletal maturity)
  • Several comorbidities
  • Neurological problems
  • Problems while sitting
• Etiology
  • Neuromuscular
    • = causing muscle weakness or asymmetry
    • Spinal muscular atrophy
    • Cerebral palsy
    • Duchenne muscular dystrophy
  • Congenital (abnormal vertebrae)
    • Wedge vertebrae
    • Block vertebrae
    • Hemiblock vertebrae
  • Syndromic
    • Neurofibromatosis
      • MRI should be performed to look for neurofibromas
    • Marfan syndrome
    • Ehlers-Danlos syndrome
• Treatment
  • Neuromuscular scoliosis
    • Growing rods until growth is finished
    • Spinal fusion surgery (of Luque)
  • Congenital scoliosis
    • Surgery to correct the congenital abnormality
  • Syndromic scoliosis
    • Same as for adolescent idiopathic scoliosis

51. Idiopathic structural scoliosis

• Structural scoliosis is idiopathic in 80% of cases
• Adolescent idiopathic scoliosis (AIS)
  • 11 – 18 years
  • Lenke classification system
    • The gold standard for classification of AIS
    • Helps plan surgeries
  • Risser sign
    • = degree of ossification of the iliac apophysis across the iliac crest
    • Is used to estimate the skeletal maturity of the vertebral column and to guide treatment
      • -> more mature = less risk of scoliosis progressing
      • -> less mature = more risk of scoliosis progressing
      • Spinal fusion surgery can only be performed on those with mature skeleton
        • If Risser 2 or lower -> conservative treatment
        • If Risser 3 or higher -> spinal fusion surgery
    • Risser 1 = 25% of the iliac crest is ossified
    • Risser 2 = 50%
    • Risser 3 = 75%
    • Risser 4 = 100% of the iliac crest is ossified
    • Risser 5 = the iliac crest is fused to ileum
  • Skeletal maturity can also be planned based on menarche
    • We say that 2 years after menarche the skeleton is mature enough for spinal fusion surgery
  • Poor prognostic factors (factors which increase risk of curve progression)
    • These factors are important to determine how often a check-up should be performed
    • Female
    • Age of onset
    • Greater Cobb angle
    • Scoliosis of upper spine
    • Bigger vertebral rotation
    • Bigger rib-vertebral angle difference (RVAD)
  • Treatment
    • Conservative
      • Used for Risser 2 and below while waiting for skeletal maturity, and for < 50 degree Cobb
      • Schroth therapy
        • = special 3D training exercises
        • These exercises not only stops progression but can cause regression of curve
      • Cheneau brace
        • Should be worn for 20 hours per day
        • Must be combined with physical exercise
        • The brace helps stopping the progression but does not cause regression
    • Surgery
      • Posterior instrumented fusion with direct vertebral rotation
        • A form of spinal fusion surgery
        • Gold standard
        • Involves placement of screws and rods
      • Osteotomies
        • On rigid spines
    • Cobb angle 15 – 20 degrees
      • Night-time brace + Schroth therapy
      • Only observation (if non-progressive curve)
    • Cobb angle 20 – 40 degrees
      • Cheneau brace + Schroth therapy
    • Cobb angle 50 – 65 degrees -> Surgery
      • Surgery at this stage corrects the cosmetic problem and prevents later back pain
    • Cobb angle > 65 degrees -> Surgery
      • Surgery at this stage not only corrects the cosmetic problem and prevents later back pain, but also prevents severe cardiorespiratory complications
• Early onset scoliosis
  • Treatment is not based on fusion (as in AIS) but rather uses unilateral growing rods
  • Many cases resolve spontaneously