Congenital Constriction Bands (Amniotic Band Syndrome)

• Ruptured amnion: Amnion tears early in pregnancy
• Fibrous bands: Amniotic bands wrap around developing limbs
• Constriction: Bands constrict blood flow and growth
• Variable severity: Depends on timing and tightness of constriction
• Not genetic: Sporadic, not inherited

• Maternal factors: Trauma, infection, drug use (controversial)
• Early amnion rupture: More severe if occurs early in pregnancy
• Multiple gestations: Slightly increased risk
• Most cases: No identifiable risk factor (idiopathic)

Amnion tears early in pregnancy (often first trimester):

• Amniotic fluid leaks, amnion separates from chorion
• Fibrous bands form from torn amnion
• Bands float in amniotic fluid and can wrap around developing fetus
• Constriction occurs as fetus grows

Severity depends on:

• Timing of amnion rupture (earlier = more severe)
• Tightness of band constriction
• Location of constriction (digits vs limb)
• Duration of constriction before birth
• May cause vascular compromise, lymphatic obstruction, or complete amputation

• Prenatal history: Maternal trauma, infection, drug use?
• Birth history: Normal delivery? Any complications?
• Family history: Other congenital anomalies? (Usually negative - not genetic)
• Progression: Is constriction getting worse? (Grade 2 may progress)
• Symptoms: Pain, swelling, functional limitations?
• Multiple sites: Check all limbs and digits

• Distal swelling: Indicates Grade 2, needs urgent assessment
• Color changes: Blue/purple distal to band suggests vascular compromise
• Progressive constriction: May indicate active band tightening
• Multiple severe bands: May be part of more complex syndrome

• AP and lateral views: Assess bone structure, any underlying anomalies
• Distal hypoplasia: May see shortened or underdeveloped bones
• Fusion: In Grade 3, may see bony fusion of digits
• Not diagnostic: Clinical diagnosis, X-rays confirm extent

• Vascular assessment: If Grade 2 with edema, assess arterial flow
• Lymphatic obstruction: May see dilated lymphatics
• Not routine: Usually clinical diagnosis sufficient

• Managed in paediatric orthopaedic/plastic hand units with multidisciplinary limb-deficiency clinics
• Antenatal ultrasound increasingly detects bands and threatened limbs; selected fetoscopic release offered in a few fetal-surgery centres (Cincinnati, European units) for progressive limb or cord constriction
• Microsurgical toe-to-hand transfer and prosthetics available for severe loss

• Frequently diagnosed only postnatally (limited antenatal screening) — case reports from Somalia and Burkina Faso illustrate first documented presentations
• Emphasis on simple band release / Z-plasty under local or topical anaesthesia where theatre access is limited
• Prosthetic provision and staged reconstruction often constrained; early simple release of threatening Grade 2 bands remains the priority intervention

• Patterson classification as the shared language
• Urgent release of bands with distal lymphoedema/vascular threat
• Single- or two-stage circumferential excision with opposing flaps (Z-plasty or Y-to-V) preferred over piecemeal release
• Sporadic aetiology — reassurance regarding negligible recurrence risk

• Patient selection for fetoscopic release (limb salvage vs PPROM risk) is undefined
• Optimal timing of acrosyndactyly separation (early neonatal vs 3-6 months) is debated
• Best technique to avoid residual hourglass deformity after circumferential release
• Whether maternal medication associations are causal or confounded