FRCS Revision

This site is private

Enter the password to open the revision library.

Personal revision library · not clinical advice
FRCSRevision
Home / Spine Paed / Scoliosis assessment and Cobb angle
Spine Paed

Scoliosis assessment and Cobb angle

Deformity examination, radiographic features, vertebral rotation and Cobb angle measurement.

23 questions 2 source pages

Images appear with the first question taken from each source page — tap a question to open it.

23 questions
Q1What are the indications for MRI in scoliosis?▸
  • Left-sided thoracic curve
  • Short angular curve, angled kyphosis
  • Neurology, pain
  • <10yr + >20 deg (<10 years + >20 degrees)
  • Rapid curve progression
Q2How do you assess maturity and risk of progression?▸
  • Age 9-13 with >2 years before menarche
  • growth rate >2cm/yr (>2cm/year)
  • Risser 0-1, hand XR capped stage (TW III), open triradiate cartilage
  • Risser stages: I prepubertal, II growth spurt, III decreasing growth rate, IV variable
  • Limitations: peak height velocity and 2/3 of growth spurt occur before Risser I; curve may not stop at Risser IV
Q3What is the brace treatment and its evidence?▸
  • The aim of the brace is to slow down curve progression; effect is dosage related (>20 hr/day -> 93% success)
  • Keep bracing till skeletal maturity
  • Weinstein BRAIST trial (NEJM 2013): 72% success vs 48% observation
  • Complications: GI regurgitation, skin irritation/dermatitis/folliculitis, pressure, low self-esteem
Q4What are the indications and aims of surgery in AIS?▸
  • Curves >45 degrees in a growing patient or >50 degrees when growth has stopped
  • Aim: correct deformity, square fusion block with <2cm listing and <20 degree tilt
  • Include all structure curves (i.e. all structural curves) while saving fusion segments
  • Stable fusion and prevent complications
Q5Compare anterior and posterior fusion in AIS.▸
  • Anterior: short segment, increase correction power by discectomy, for hypokyphosis; disadvantage difficult exposure
  • Posterior: easy exposure; disadvantage long segment, difficult full correction
  • Combined indications: stiff curve (>50 residual on FB XR), severe curve (>70), immature (female <10, male <13) to prevent crankshaft
Q6Why operate in AIS (natural history)?▸
  • Progression >50 degrees -> more likely SOB; >70 deg --> decreased lung function; >100 deg increase risk of death
  • Increased mortality and cardiopulmonary compromise
  • Truncal imbalance and back pain
Q7Describe the XR findings in this AIS case.▸
  • Major right thoracic curve, apex T8/9, Cobb angle 40 degrees
  • Shoulders and pelvis level; truncal shift and truncal listing
  • No vertebral anomalies such as hemivertebrae or unsegmented bar, ribs normal; Risser sign 3; Triradiate cartilage status
Q8What history and maturity assessment is needed in AIS?▸
  • Birth history, developmental history and family history of scoliosis
  • Current symptoms: age of onset and progression, pain or neurological symptoms, visceral problems
  • Assess maturity: menarche, growth spurt
Q9What are the components of the general and standing examination in AIS?▸
  • General: body height, arm span, sitting height; cutaneous lesions; ligamentous laxity/marfanoid features; spinal dysraphism
  • Standing coronal: shoulder/pelvis symmetry, rib or loin hump, decompensation (truncal shift and list)
  • Sagittal: hypokyphosis, kyphoscoliosis; bend forward for flexibility; gait (scissoring gait)
  • Sit: postural scoliosis; supine: neuro exam + superficial abdominal reflexes; finish by checking secondary sexual characteristics
Q10Which classifications are used for AIS curves?▸
  • Lenke classification, King classification, Peking Union Medical College (PUMC), Labelle 3D
  • This case is a major thoracic curve
Q11How is a brace weaned in AIS?▸
  • At skeletal maturity: no growth in 18 months, Risser 4, menarche >2 years, DR and DU physis closed
  • Done in a gradual manner - no hard science; e.g. spread over 4 months with stepwise decrease in hours/day
Q12What are the key elements of scoliosis surgery?▸
  • Posterior approach; subperiosteal dissection till transverse processes
  • Identify upper and lower instrumented vertebrae (ASF: end to end; PSF: proximal end; distal Lenke I-II: most distal VB touched by CVSL, III-VI: distal end VB)
  • Pedicle screw insertion; reduction techniques: Harrington forces, cantilever bending, translation, rod rotation, direct vertebral rotation
  • Decortication with bone graft to interlaminar space and into facets
Q13Describe the Hong Kong scoliosis screening programme.▸
  • 3 tier system starting in P5
  • FBT + ATR >=15 -> refer to scoli centre
  • 5-14: Moire topography -> >=2 lines -> XR -> >20 degrees -> refer specialist hospital
  • <5: re-refer to screening programme
Q14What is spinal bifida and what are its risk factors?▸
  • Fetal neural plate fails to completely close
  • Risk factors: folate deficiency, maternal diabetes, chromosomal abnormality
Q15List the forms of spinal bifida.▸
  • Spina bifida occulta: cord and meninges confined
  • Meningocele: protruded sac, no neural elements
  • Myelomeningocele: protruded sac with neural elements
  • Rachischisis: neural elements exposed
Q16What causes neurological deterioration in spinal bifida?▸
  • Tethered cord
  • Hydrocephalus
  • Syringomyelia
Q17How is the functional level assessed in spinal bifida?▸
  • Walk? yes at least L3
  • Ankle equinus? no at least L4
  • Hip abduction? yes at least L5
  • If not walking: check hip control - no at L1 or above, yes with flexion at L2
Q18What are the principles of treatment in spinal bifida?▸
  • Treatment depends on the form and level
  • Aim: maximise function consistent with the level involved and prevent deterioration
  • Multidisciplinary approach with patient and family counselling
  • Community-based treatment, minimise hospital admission
  • Orthosis and physiotherapy for stretching to prevent contracture and maintain muscle power
  • Surgery to balance muscle pull, prevent or correct deformity
Q19How are the hip, knee and ankle managed surgically in spinal bifida?▸
  • Hip: highest dislocation rate at L3/L4 last functional level due to adductor-abductor imbalance
  • Hip surgery is controversial and only applicable with functional quadriceps
  • Knee: flexion contracture release if severe and affecting walking
  • Ankle: can be equinovarus, cavovarus or calcaneovalgus
Q20What are the physical examination findings in spina bifida?▸
  • Very short and slim lower limbs, upper limbs normal, AFO
  • Scar: longitudinal, mostly at the back
Q21How does spina bifida present?▸
  • Deformity due to imbalanced muscle pull (hip dislocation, ankle deformity)
  • Contracture
  • Scoliosis (congenital / muscle imbalance / secondary to unilateral hip dislocation with LLD)
  • Functional deficit (walking difficulty)
  • Neurogenic bladder
  • Foot deformities
Q22What causes scoliosis in spina bifida?▸
  • Congenital curve
  • Muscle imbalance
  • Secondary to unilateral hip dislocation with LLD
Q23At which functional level is hip dislocation the highest risk in spina bifida and why?▸
  • L3 (with L4, the last functional levels) - intact adductor but weak abductor
  • L3 patients are household walkers
← Early-onset scoliosis and growing rodsAdolescent idiopathic scoliosis →