Humeral congenital constriction band in an extremely preterm infant: single-stage circumferential release and neurovascular decompression using multiple Z-plasties.

Background: Amniotic band syndrome (ABS) is a rare sporadic disorder in which fibrous bands of amniotic origin encircle and progressively constrict developing fetal structures. Humeral involvement is exceptionally rare and threatens the brachial neurovascular bundle. Case presentation: A male infant born at 28 weeks and 4 days of gestation was referred at 6 months of chronological age with a single circumferential constriction band of the proximal third of the left humerus (Patterson type 2). Active motion was globally restricted at the shoulder, elbow and wrist, with moderate distal lymphoedema, active finger flexion reduced but present, preserved finger extension and no wrist drop. Perfusion and withdrawal to tactile stimulation were preserved in all digits; the thenar eminence was hypotrophic and the affected hand was smaller than the contralateral hand. Preoperative radiographs confirmed maintained osseous alignment. Surgery was undertaken at 9 months of chronological age, approximately 6.5 months corrected. The band was excised in its entirety using multiple interdigitating Z-plasties; the brachial artery and the radial, median and ulnar nerves were individually identified and decompressed, were normal in calibre, and neurolysis was not required. At 16 months the wounds were healed, all flaps viable, the distal lymphoedema resolved and the groove fully effaced. Electrodiagnostic studies were not performed preoperatively; nerve conduction studies have since been requested. Conclusions: Single-stage circumferential Z-plasty release with decompression of the brachial neurovascular bundle can be performed safely at the humeral level in an extremely preterm infant. We make no claim regarding neurological recovery, since electrodiagnostic studies were not obtained; the coexisting thenar hypotrophy and reduced hand size raise the possibility of a distal developmental component that decompression would not address, underlining the value of an objective neurological baseline at first presentation.