"Horseshoe cord terminus" sans filum around a bone spur: a rare composite of faulty gastrulation with agenesis of secondary neurulation: case report.

Split cord malformation (SCM) is classified based on the presence of a bone spur and double dural sac. The authors report on a 6-year-old child with primary enuresis in whom MRI findings were suggestive of Type I SCM, and who had unique intraoperative findings of a horseshoe-shaped split cord terminus anchored by a bone spur without the normally tapering conus and filum. The typical appearance of cauda equina was absent, with all the roots arising from the horseshoe cord terminus. This composite anomaly is probably due to the rare combination of faulty gastrulation with abnormal persistence of endomesenchymal tract causing SCM, with concurrent agenesis of secondary neurulation in turn causing absence of filum.