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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