Myelomeningocele

The insensate, osteopenic lower limb in MMC fractures easily and deceptively - a trap examiners love.

• Why: disuse osteopenia (limited weight-bearing) plus insensate bone means a low-energy fracture, classically of the distal femoral or proximal tibial metaphysis/physis, often appearing after a period of cast immobilisation (which worsens the osteopenia) once the cast is removed.
• The trap: because the limb is insensate the child has little or no pain. The fracture instead presents as a warm, swollen, erythematous limb, often with a low-grade fever and raised inflammatory markers - readily mistaken for osteomyelitis or cellulitis (and sometimes a Charcot/neuropathic process). The radiograph (showing the fracture and, later, exuberant callus) is the key to the diagnosis.
• Management: gentle, well-padded immobilisation (a soft splint or bandage rather than a tight cast) - the fracture heals rapidly with abundant callus - while obsessively protecting the insensate skin from pressure sores. Aggressive surgery and unnecessary antibiotics are avoided.

Clinical Imaging Atlas

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The visible back lesion and the pattern of neurological deficit must be distinguished from other dysraphic and neuromuscular conditions, because management and prognosis differ sharply.

Latex Allergy:

• Affects 30-70% of MMC patients (depending on definition).
• Sensitization occurs from repeated mucosal exposures (surgeries, catheterizations).
• Prevention: Latex-free environment from birth.
• Signs: Urticaria, Angioedema, Bronchospasm, Anaphylaxis.

Renal failure from an untreated neurogenic bladder is a leading cause of late death in MMC - the bladder, not the legs, often determines survival.

• The hostile bladder: the danger is a high-pressure system - a poorly-compliant or hyperreflexic detrusor working against a closed sphincter (detrusor-sphincter dyssynergia). Sustained high storage pressure (a detrusor leak-point pressure above about 40 cmH2O is the classic threshold) is transmitted to the upper tracts, causing vesico-ureteric reflux, hydronephrosis and progressive renal scarring.
• Surveillance: baseline and serial urodynamics plus renal ultrasound identify the hostile bladder before the kidneys are damaged - a silent process, because the child cannot feel it.
• Management ladder: clean intermittent catheterisation (CIC) plus anticholinergics to keep storage pressures low is first-line; escalate to intradetrusor botulinum toxin, then augmentation cystoplasty - often with a continent catheterisable Mitrofanoff channel, and a MACE/antegrade continence enema for the bowel - for the refractory hostile bladder.

• Wound Care: Paramount due to insensate skin. Padding. Frequent skin checks.
• Latex Free: Non-latex catheters, gloves, IV tubing.
• Positioning: Avoid pressure on surgical sites and insensate areas.
• Rehabilitation: Intensive physio for gait training post lower limb surgery.

• Survival: Greater than 80% survive to adulthood with modern care.
• Ambulation: Sacral levels walk independently. Thoracic levels are wheelchair-dependent.
• Cognition: Approximately 80% have normal IQ, though learning disabilities are common.
• Quality of Life: Can be excellent with multidisciplinary support.
• Mortality: Primarily from renal failure and shunt complications.

Global Epidemiology:

• NTD birth prevalence varies widely with diet, fortification policy and prenatal screening: roughly 0.5-1 per 1000 in fortified, high-income settings, but markedly higher in regions without fortification (parts of South Asia, the Middle East and sub-Saharan Africa report several per 1000).
• Mandatory folic-acid fortification of staple flour (adopted by the USA, Canada, Australia, much of Latin America and a growing number of African and Asian countries) has reduced NTD prevalence by an estimated 30-50% at population level. Many European countries still rely on voluntary supplementation alone, where uptake is incomplete.

Side-by-Side Guidance (where recommendations differ):

• Timing and selection for fetal repair: MOMS/MOMS2 established benefit, but eligibility is narrow and maternal/obstetric risk (preterm birth, uterine dehiscence) is real. Fetoscopic techniques aim to reduce maternal morbidity, but comparative long-term neurological data versus open repair remain immature.
• Prophylactic vs symptomatic untethering: Almost all repaired cords are radiologically "tethered". There is no consensus to operate on a radiologically low conus in the absence of clinical or urodynamic deterioration - surveillance, not the MRI appearance alone, drives surgery.
• The dislocated hip: Whether to reduce a unilateral or bilateral dislocation in a mid-lumbar (L3-L4) ambulator is genuinely contested; many units now prioritise a level pelvis and balanced sitting over radiographic reduction.
• Kyphectomy: Effective for severe rigid gibbus interfering with sitting and skin integrity, but carries high rates of wound breakdown, implant failure and blood loss; indications and fixation strategy vary between centres.
• Folic-acid dosing for prevention vs recurrence: 0.4 mg/day for general prevention vs 4-5 mg/day for women with a prior affected pregnancy; the optimal dose and the role of universal fortification in voluntary-supplementation countries remain debated.