Urethral obstruction sequence and lower limb deficiency: evidence for the vascular disruption hypothesis.

We reviewed five unreported examples and 23 previously reported cases of urethral obstruction sequence with associated lower limb deficiency. There was no evidence of amniotic bands or exposure to vasoactive drugs during pregnancy in any case. In three infants a gangrenous lesion at the distal part of the affected leg was found; in another three infants, necrotic tissue was noted in the stump of the affected leg. This type of lesion can be explained only on a vascular ischemic basis. In five cases, signs of compression of the external iliac artery by the grossly distended bladder, by grossly distended ureters, or both were found. A vascular disruption in the territory of the external iliac artery caused by compression by the distended urinary tract is the proposed mechanism for the associated limb deficiency.