Classic history and presentation: Patients present at birth with constrictive bands perpendicular to the longitudinal axis of the limb. Diagnosis can be made in utero during anatomic ultrasound scans.
Prevalence: 1:15 000 live births
- Age – Diagnosed at birth.
- Sex / gender – Males and females are equally predisposed.
Pathophysiology: There is no well-established etiology; however, most experts agree that the disrupted amnion releases fibrous membranous strands. These strands wrap around the developing limb circumferentially, which restricts the remaining growth of that limb.
Grade / classification system: Patterson classification.
- Type 1: Simple constriction ring.
- Type 2: Deformity distal to ring (hypoplasia, lymphedema) with or without edema.
- Type 3: Fusions distally (such as syndactyly or acrosyndactyly).
- Type 4: Amputation.