High Yield Overview
Spina Bifida
Myelomeningocele and Orthopaedic Care
1-2 per 1000 (pre-folate)Incidence
Folate SupplementationPrevention
—Ambulatory Depends on Level
UniversalOrthopaedic Issues
Ambulatory Potential by Level
Thoracic
PatternNo lower limb function.
TreatmentWheelchair
L1-L2 (High Lumbar)
PatternHip flexion only.
TreatmentStanding frames, limited ambulation
L3-L4 (Mid Lumbar)
PatternKnee extension present.
TreatmentCommunity ambulation with aids
L5-Sacral
PatternAnkle function present.
TreatmentCommunity ambulation, minimal aids
Critical Must-Knows
- Neurological Level: Determines ambulatory potential.
- Hip Dysplasia: Common but treatment controversial.
- Clubfoot: Often rigid, surgical.
- Scoliosis: Congenital and neuromuscular types.
- Fractures: Insensate limbs prone to pathological fractures.
Examiner's Pearls
- "Level determines function
- "Hip surgery controversial
- "Clubfoot needs surgery
- "Insensate = fracture risk
Clinical Imaging
Imaging Gallery
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Insensate Limbs
Patients with Spina Bifida have INSENSATE lower limbs below the lesion level.
- Pathological fractures occur with minimal trauma.
- Pressure sores are common - careful orthotic fitting essential.
- Post-operative cast care must be meticulous.
- Teach patients/families to check skin daily.
At a Glance
| Feature | Details |
|---|---|
| Definition | Neural tube defect with failure of spinal column closure |
| Incidence | 0.5-1 per 1000 live births (Australia) |
| Prevention | Folic acid supplementation (400-800 mcg/day periconceptually) |
| Key Determinant | Neurological level determines ambulatory potential |
| Peak Presentation | Diagnosed prenatally or at birth |
| Orthopaedic Issues | Universal - hip, spinal deformity, feet, fractures |
Ambulatory Potential by Level
| Level | Key Muscle | Ambulatory Potential |
|---|---|---|
| None below | Wheelchair | |
| Hip flexors | Standing frames only | |
| Quadriceps | Community with AFOs | |
| Ankle dorsiflexion/plantar flex | Community, minimal aids |
Mnemonic
Neurological Level and Function
L1
Hip Flexion
Iliopsoas
L2
Hip Adduction
Adductors
L3
Knee Extension
Quadriceps
L4
Ankle Dorsiflexion
Tibialis Anterior
L5
Ankle Eversion
Peroneals
S1
Plantar Flexion
Gastrocnemius
Memory Hook:L1-2-3-4-5, S1 = Hip Flex/Add, Knee Ext, Ankle Dorsi/Evert, Plantar Flex.
Mnemonic
Orthopaedic Issues
H
Hips
Dysplasia, subluxation
S
Spine
Scoliosis (congenital/neuromuscular)
F
Feet
Clubfoot, vertical talus
K
Knees
Contractures
Memory Hook:HSFK - Hips, Spine, Feet, Knees.
Mnemonic
Hip Treatment Controversy
R
Reduction doesn't change walking
Old studies
C
Controversial
Some advocate for sitting balance
F
Functional needs
Consider individual patient
Memory Hook:RCF - Reduction controversial, consider function.
Overview/Epidemiology
Spina Bifida is a neural tube defect where the spinal column fails to close during the first 28 days of embryonic development.
Types of Spina Bifida
-
Myelomeningocele (95% of cases):
- Most severe open form - exposed neural placode
- Spinal cord and meninges herniate through defect
- Associated with significant neurological deficit
- Requires immediate surgical closure after birth
- Nearly always associated with Chiari II malformation
-
Meningocele (4%):
- Meninges herniate through defect, spinal cord intact
- Usually better neurological function
- May present as lumbosacral mass at birth
- Surgical closure required
-
Spina Bifida Occulta (1%):
- Minor posterior arch defect without herniation
- Often asymptomatic, incidental finding
- Skin markers: Hair tuft, dimple, lipoma, hemangioma
- May be associated with tethered cord
Epidemiology
- Incidence: 0.5-1 per 1000 live births in Australia (reduced with folate fortification)
- Historical incidence: 2-4 per 1000 pre-folate supplementation
- Sex ratio: Slight female predominance
- Geographic variation: Higher in Celtic populations
Prevention - Australian Context
- Mandatory flour fortification: Since 2009 in Australia/New Zealand
- Periconceptual supplementation: 400-800 mcg folic acid daily
- High-risk women: 5 mg daily (previous NTD pregnancy, epilepsy medications)
- Reduction achieved: 40-60% reduction in NTD rates
Associated Conditions
- Chiari II Malformation: Nearly 100% with myelomeningocele
- Hydrocephalus: 80-90% require VP shunt
- Tethered Cord: May develop progressively
- Syringomyelia: Common finding on MRI
- Neurogenic Bladder: Universal below lesion level
- Neurogenic Bowel: Requires bowel management program
- Cognitive Impairment: Variable, often preserved intelligence
Anatomy and Pathomechanics
Neurological Level and Motor Function
- The level of the lesion determines muscle function below
- Motor function is predictable based on spinal level
- Sensation is typically absent below the lesion
- The motor level often differs from the sensory level
| Nerve Root | Key Muscle | Function | Clinical Test |
|---|---|---|---|
| L1 | Iliopsoas | Hip flexion | Observe hip flexor power |
| L2 | Iliopsoas, Adductors | Hip flexion/adduction | Hip adduction against resistance |
| L3 | Quadriceps | Knee extension | Knee extension against gravity |
| L4 | Tibialis Anterior | Ankle dorsiflexion | Walk on heels |
| L5 | EHL, Peroneals | Great toe extension, eversion | Great toe dorsiflexion |
| S1 | Gastrocnemius | Ankle plantarflexion | Single leg heel raise |
| S2-4 | Bladder/Bowel | Continence | Urodynamics |
Pathogenesis of Orthopaedic Deformities
Muscle Imbalance Principle
- Active muscles without functioning antagonists cause progressive deformity
- Example: Active hip flexors (L1-L2) without extensors (L5-S1) = hip flexion contracture
- Example: Active quadriceps (L3) without hamstrings = knee hyperextension
Specific Deformity Patterns by Level
-
Thoracic Level:
- No lower limb motor function
- Paralytic hip dislocation (both hips)
- Spinal deformity common (100% have scoliosis)
- Severe kyphosis may interfere with sitting
-
High Lumbar (L1-L2):
- Hip flexors active, extensors absent → flexion contracture
- Hip adductors active without abductors → adduction contracture
- Progressive hip subluxation/dislocation (muscle imbalance)
- Knee flexion contractures common
-
Mid Lumbar (L3-L4):
- Quadriceps active → community ambulators
- Hip instability less severe
- Knee extension possible but may have hyperextension
- Foot deformities common (clubfoot, calcaneus)
-
Low Lumbar (L5-S1):
- Near-normal motor function
- Mild foot deformities (pes cavus, clawing)
- Good ambulatory potential
- Less severe spinal issues
Why Orthopaedic Issues Are Universal
- Muscle Imbalance: Drives most deformities
- Lack of Sensation:
- No protective sensation → unrecognized trauma
- Pressure sores under braces and casts
- Pathological fractures present with swelling (no pain)
- Gravity and Positioning:
- Unopposed forces create contractures
- Hip flexion contracture from prolonged sitting
- Osteoporosis:
- Insensate, non-weight-bearing limbs become osteoporotic
- High fracture risk with minimal trauma
Classification Systems
Classification by Neurological Level
- Thoracic: No lower limb motor function. Wheelchair-bound.
- High Lumbar (L1-L2): Hip flexion only. Standing frames.
- Mid Lumbar (L3-L4): Quadriceps active. Community ambulation with AFOs.
- Low Lumbar (L5): Ankle dorsiflexion. Good ambulators.
- Sacral: Ankle plantar flexion. Near-normal walking.
Clinical Assessment
History
Essential Information
- Neurological level: Documented motor and sensory level
- Ambulatory status: Current and best function achieved
- Bladder/bowel function: Clean intermittent catheterization, bowel program
- Prior surgeries: Closure, shunt, orthopaedic procedures
- Shunt status: Type, last revision, symptoms of malfunction
Red Flags to Identify
- Shunt malfunction symptoms: Headache, vomiting, irritability, decreased consciousness
- Tethered cord symptoms: Deteriorating gait, new weakness, increasing scoliosis, change in bladder function
- Skin breakdown: Location, duration, prior wounds
- Recent fractures: Often missed due to lack of pain
Physical Examination
Neurological Assessment
- Motor level: Test each myotome systematically
- Sensory level: Light touch and pinprick
- Reflexes: May be variable depending on level
- Document baseline for comparison
Spine Examination
- Scoliosis assessment: Adam's forward bend test, trunk shift
- Kyphosis: Lumbar kyphosis common, rigid vs flexible
- Skin over spine: Scars, sinus tracts
- Sitting balance: Essential for wheelchair users
Hip Examination
- Range of motion: Document flexion contracture (Thomas test)
- Hip stability: Barlow/Ortolani in infants, assess with motion
- Gait: If ambulatory, observe pattern
- Sitting posture: Pelvic obliquity from hip problems
Knee Examination
- Flexion contractures: Common, limit ability to use orthoses
- Hyperextension: May occur with quadriceps function
- Extension lag: Quadriceps strength assessment
Foot Examination
- Deformity type: Clubfoot, vertical talus, calcaneus, cavus
- Rigidity: Assess correctability
- Skin: Pressure points, calluses, ulcers
- Braceable: Can foot fit in AFO without pressure issues?
Skin Examination
- Critical assessment - insensate skin very vulnerable
- Under braces and orthoses
- Bony prominences
- Prior wound sites
- Signs of infection
Ambulatory Classification
| Level | Motor Function | Ambulatory Potential | Orthotic Needs |
|---|---|---|---|
| Thoracic | None below | Wheelchair only | Standing frame (therapeutic) |
| L1-L2 | Hip flexors | Standing frames | HKAFO, wheelchair primary |
| L3-L4 | Quadriceps | Community ambulation | KAFO or AFO |
| L5 | Ankle dorsiflexion | Community, minimal aids | AFO, often supramalleolar |
| Sacral | Plantarflexion | Near-normal | Shoe inserts only |
Investigations
Imaging:
- Spine X-ray: Scoliosis, kyphosis, vertebral anomalies.
- Hip X-ray: DDH, subluxation.
- Foot X-ray: Clubfoot, talus position.
- MRI Spine: Tethered cord (before scoliosis surgery).
Other:
- EMG: If level unclear.
- Urodynamics: Bladder function.
Management Algorithm
Hip Management
- High Lumbar (L1-L2): Treatment controversial. Many do not operate.
- Mid-Low Lumbar: May benefit from reduction if ambulatory potential.
- Surgical Options: Open reduction, femoral/pelvic osteotomy.
- Salvage: McHale (proximal femoral resection-interposition).
Surgical Techniques
Scoliosis Surgery in Spina Bifida
Indications
- Progressive curve greater than 40-50 degrees
- Declining sitting balance affecting function
- Trunk imbalance causing pain or skin breakdown
- Pulmonary compromise (rare)
Pre-operative Planning
- MRI Spine: Exclude tethered cord - if present, release first
- Neurosurgery consultation: Shunt assessment
- Latex-free OR: Pre-order all equipment
- Blood typing: High blood loss procedure
- Nutritional optimization: Many are malnourished
Surgical Technique
- Posterior spinal fusion: Standard approach
- Fusion levels: T2 to pelvis for wheelchair users
- Pelvic fixation: Iliac screws or Galveston technique
- Avoid short fusions: High failure rate
- Bone graft: Consider allograft supplementation
Key Considerations
- Latex allergy: Universal precautions
- Poor bone quality: Larger, longer screws needed
- Skin closure: May be difficult over kyphosis
- Shunt: Position carefully, avoid kinking
- Post-op: Custom seating may be needed
Complications
Complications of Spina Bifida - Orthopaedic Focus
| Complication | Incidence | Presentation | Management |
|---|---|---|---|
| Pressure Sores | Very common | Skin breakdown over bony prominence | Prevention, wound care, plastic surgery |
| Pathological Fractures | 20-30% | Swelling, warmth (mimics infection) | Gentle splinting, avoid immobilization |
| Latex Allergy | 30-70% | Anaphylaxis, urticaria | Latex-free OR environment |
| Tethered Cord | Progressive | New weakness, scoliosis progression | MRI, neurosurgical release |
| Shunt Malfunction | Variable | Headache, vomiting, altered consciousness | Urgent neurosurgery |
Pressure Sores - Critical Issue
High-Risk Areas
- Under braces and orthoses
- Ischial tuberosities (wheelchair users)
- Sacrum and coccyx
- Heels and malleoli
- Over prominent hardware
Prevention Strategies
- Regular skin checks (daily for at-risk areas)
- Properly fitted orthoses - check at every visit
- Pressure-relieving cushions for wheelchairs
- Weight shifts and position changes
- Patient/family education
Management When Present
- Remove all pressure from area
- Wound care (may need plastic surgery)
- Underlying osteomyelitis may require debridement
- Can take months to heal
Pathological Fractures
Why They Occur
- Insensate, osteoporotic bone
- Minimal or no trauma recognized
- Common in femur, tibia
Presentation
- Swelling and warmth (no pain)
- Often mistaken for infection
- May have low-grade fever (fracture hematoma)
Management
- Gentle splinting only
- Avoid prolonged immobilization - worsens osteoporosis
- Limited casting (causes pressure sores)
- Healing usually occurs but may be slow
Perioperative Complications
Latex Allergy
- Present in 30-70% of spina bifida patients
- Due to repeated procedures and latex exposure
- Mandatory latex-free OR for all procedures
- Pre-operative antihistamines in known cases
Shunt Considerations
- Inform neurosurgery of planned surgery
- Position to avoid pressure on shunt
- Monitor for signs of malfunction post-op
- May need shunt adjustment for positioning
Wound Healing
- Poor skin quality common
- Increased infection risk
- Consider plastic surgery involvement for complex closures
- Extended antibiotics often required
Postoperative Care
Immediate Postoperative Period
Skin Monitoring
- Critical in first 48-72 hours
- Cast windows for skin inspection
- Bivalved casts when possible
- Daily skin checks by nursing staff
- Teach family to inspect on discharge
Positioning
- Avoid pressure on shunt
- Pressure-relieving mattress
- Regular turning (every 2 hours minimum)
- Heel protection mandatory
Pain Management
- May have diminished pain perception
- But still need adequate analgesia - central processing intact
- Watch for signs of discomfort (irritability, vital signs)
- Regional blocks can be effective
Cast Care in Spina Bifida
Special Considerations
- Insensate limbs cannot report problems
- Window cast to inspect wound and skin
- Well-padded, especially at bony prominences
- Not too tight - allow for swelling
- Parents must check edges daily
Duration
- Often shorter than typical (skin tolerance)
- Transition to orthosis when safe
- Careful molding to prevent pressure points
Rehabilitation
Goals by Level
- Thoracic: Maximize upper body strength, wheelchair skills
- L1-L2: Standing program if appropriate, transfers
- L3-L4: Gait training with appropriate orthoses
- L5-Sacral: Optimize gait efficiency, minimize energy expenditure
Orthotic Management
- Fitted by experienced orthotist
- Check fit at every clinic visit
- Anticipate growth - regular adjustments
- Replace when worn or outgrown
Outcomes/Prognosis
Ambulatory Outcomes by Level
| Level | Community Ambulation Rate | Long-term Mobility |
|---|---|---|
| Thoracic | 0% | Wheelchair-dependent |
| L1-L2 | 0-10% | Standing frames, wheelchair primary |
| L3-L4 | 50-80% | Community ambulation common |
| L5-Sacral | 80-100% | Near-normal ambulation |
Factors Affecting Outcome
Positive Prognostic Factors
- Lower neurological level (L4-Sacral)
- Preserved cognition
- Strong family support
- Access to multidisciplinary care
- Early intervention for deformities
Negative Prognostic Factors
- Higher lesion level
- Significant cognitive impairment
- Multiple shunt revisions
- Severe scoliosis
- Recurrent pressure sores
Life Expectancy
- Significantly improved with modern care
- Most patients with myelomeningocele reach adulthood
- Main causes of death: Shunt-related, renal failure, respiratory
- Quality of life can be excellent with appropriate support
Transition to Adult Care
- Plan transition from age 14-16 years
- Identify adult orthopaedic surgeon experienced with spina bifida
- Ongoing surveillance for:
- Skin breakdown
- Progressive deformity
- New weakness (tethered cord)
- Spina Bifida Foundation support services
Evidence Base
Landmark
📚 Sharrard
Key Findings:
- Classification by neurological level
- Motor function prediction
- Foundation for understanding
Clinical Implication: Level determines function.
Source: JBJS Br 1964
Level IV
📚 Wright
Key Findings:
- Hip surgery in spina bifida
- Does not improve walking
- Controversy remains
Clinical Implication: Hip surgery is controversial.
Source: J Pediatr Orthop 2011
Review
📚 Dias
Key Findings:
- Comprehensive orthopaedic care in SB
- Multidisciplinary approach
- Focus on function
Clinical Implication: Function is the goal.
Source: J Pediatr Orthop 2020
Level IV
📚 Alman et al
Key Findings:
- Fractures in myelomeningocele
- High incidence
- Avoid immobilization
Clinical Implication: Gentle splinting for fractures.
Source: J Pediatr Orthop 1999
Level IV
📚 Menelaus
Key Findings:
- Ambulatory potential by level
- Mid-lumbar = community ambulation
- Orthotics essential
Clinical Implication: Match treatment to potential.
Source: JBJS Br 1971
Viva Scenarios
Practice these scenarios to excel in your viva examination
VIVA SCENARIOStandard
L3 Level Spina Bifida
EXAMINER
"5-year-old with L3 level spina bifida. Ambulant with AFOs. Presents with bilateral hip subluxation."
EXCEPTIONAL ANSWER
This child has **L3 level** with quadriceps function and is a **community ambulator**. The hip subluxation is common due to muscle imbalance. Management is **controversial**. Traditional teaching is that reduction does not improve walking outcomes. However, for a child who is walking, I would discuss options with the family. If the hips are **painful or affecting sitting**, I would consider reconstruction. If asymptomatic and ambulation is good, I would observe. Seating modifications may help.
KEY POINTS TO SCORE
L3 = quadriceps = ambulator
Hip surgery controversial
Observe if asymptomatic
COMMON TRAPS
✗Rushing to hip surgery
✗Ignoring ambulatory potential
LIKELY FOLLOW-UPS
"What determines ambulatory potential?"
VIVA SCENARIOStandard
Clubfoot in Spina Bifida
EXAMINER
"Same child also has rigid bilateral clubfoot. How would you manage?"
EXCEPTIONAL ANSWER
Clubfoot in spina bifida is often **rigid** and does not respond well to Ponseti casting alone. Management: I would attempt **Ponseti casting** but expect to need surgery. **Surgical options** include extensive posterior-medial release (PMR). In severe cases, a **talectomy** may be needed. The goal is a **plantigrade foot** that can be braced for ambulation. Given the insensate feet, careful postoperative skin monitoring is essential.
KEY POINTS TO SCORE
Rigid clubfoot
Surgery usually needed
Goal: plantigrade foot
COMMON TRAPS
✗Assuming Ponseti will work
✗Not monitoring skin
LIKELY FOLLOW-UPS
"What special precautions are needed for surgery?"
VIVA SCENARIOStandard
Scoliosis in Spina Bifida
EXAMINER
"10-year-old with thoracic level spina bifida. Wheelchair-bound. Thoracolumbar scoliosis 60 degrees with pelvic obliquity."
EXCEPTIONAL ANSWER
This patient has a significant scoliosis affecting sitting balance. Pre-operatively, I would order an **MRI spine to exclude tethered cord**. If present, neurosurgical release first. For surgery, I would perform **posterior spinal fusion from T2 to pelvis** with pelvic fixation. **Latex allergy** is common in spina bifida - ensure a **latex-free** OR. High complication rate due to poor skin, shunt issues. Goal is improved sitting balance.
KEY POINTS TO SCORE
MRI to exclude tethered cord
Fusion to pelvis
Latex-free environment
COMMON TRAPS
✗Not checking for tethered cord
✗Not being latex-free
LIKELY FOLLOW-UPS
"What is the shunt complication rate?"
VIVA SCENARIOStandard
Pathological Fracture
EXAMINER
"8-year-old with L2 level spina bifida presents with swelling and warmth of the left thigh. No history of trauma. Parents worried about infection."
EXCEPTIONAL ANSWER
The clinical picture suggests a **pathological fracture** rather than infection. Key differentiating features: no fever typically, swelling is circumferential, no point tenderness (insensate). I would obtain **X-rays of the femur** to confirm fracture. Blood tests (WCC, CRP) may be mildly elevated with fracture hematoma. If confirmed fracture, management is **gentle splinting** only - avoid prolonged immobilization which worsens osteoporosis. The fracture will heal but may take longer than normal. I would educate the family about fracture prevention and handling of insensate limbs.
KEY POINTS TO SCORE
Pathological fracture mimics infection
X-ray confirms diagnosis
Gentle splinting, avoid immobilization
COMMON TRAPS
✗Assuming infection without imaging
✗Prolonged casting causing pressure sores
LIKELY FOLLOW-UPS
"How do you manage casting in insensate limbs?"
MCQ Practice Points
Level MCQ
Q: A patient with L3 spina bifida has which muscle function? A: Quadriceps (knee extension). Can be a community ambulator.
Hip MCQ
Q: Does hip reduction improve walking in spina bifida? A: Controversial - traditional view is no improvement.
Foot MCQ
Q: What is the goal of foot surgery in spina bifida? A: Plantigrade foot that can be braced.
Safety MCQ
Q: What allergy is common in spina bifida? A: Latex allergy.
Spine MCQ
Q: What must be excluded before scoliosis surgery in spina bifida? A: Tethered cord - requires pre-operative MRI and neurosurgical release if present.
Fracture MCQ
Q: How does a pathological fracture present in spina bifida? A: Swelling and warmth without pain - mimics infection but occurs due to insensate osteoporotic bone.
Australian Context
Prevention in Australia
Mandatory Fortification Program
- Bread flour fortified with folic acid since 2009
- Required level: 2-3 mg per kg flour
- Estimated 40-60% reduction in neural tube defects
- Similar program in New Zealand
Periconceptual Supplementation Guidelines
- All women planning pregnancy: 400-800 mcg folic acid daily
- High-risk women (previous NTD, epilepsy medications): 5 mg daily
- Begin at least 1 month before conception
- Continue through first trimester
Australian Healthcare Resources
Multidisciplinary Spina Bifida Clinics
- Royal Children's Hospital Melbourne: Comprehensive spina bifida service
- Sydney Children's Hospital Network: Myelomeningocele clinic
- Queensland Children's Hospital: Spina bifida multidisciplinary team
- Women's and Children's Hospital Adelaide: Neural tube defect clinic
- Perth Children's Hospital: Spina bifida service
Team Composition
- Paediatric orthopaedic surgeon
- Neurosurgeon
- Paediatric urologist
- Developmental paediatrician
- Physiotherapist
- Occupational therapist
- Orthotist
- Social worker
- Spina Bifida nurse coordinator
Support Organizations
Spina Bifida Foundation of Australia
- Patient and family support
- Educational resources
- Advocacy
- State-based chapters
- Transition support programs
Equipment Funding
- NDIS funding available for:
- Wheelchairs and mobility aids
- Orthoses (AFOs, KAFOs)
- Home modifications
- Personal care support
- Aids and Equipment Programs (state-based)
- Medicare covers some orthotic costs
SPINA BIFIDA
High-Yield Exam Summary
LEVELS
- •L1-L2: Hip flexors
- •L3-L4: Quads (ambulator)
- •L5: Ankle dorsiflexion
- •Thoracic: Wheelchair
ORTHOPAEDIC
- •Hips: Controversial
- •Spine: Scoliosis/Kyphosis
- •Feet: Clubfoot
- •Fractures: Insensate
SURGERY ISSUES
- •Latex allergy
- •Tethered cord
- •Pressure sores
- •Shunt malfunction
GOALS
- •Maximize function
- •Plantigrade feet
- •Sitting balance
- •Prevent sores