Hemimyelomeningocele: a systematic review and meta-analysis of the literature.

Hemimyelomeningocele (HMM) is a rare split cord malformation where only one hemicord forms a myelomeningocele-like sac, and the opposite hemicord undergoes normal neurulation. We aimed to compile all published HMM cases to concisely summarize embryology, presentation, imaging, associated anomalies, management, and outcomes of the disorder. Following PRISMA 2020, we searched PubMed/MEDLINE, Scopus, Web of Science, and Google Scholar (1968-Feb 2025) for studies with confirmed human HMM, extracting clinical, radiological, surgical, and follow-up data. Of 688 records screened, 25 articles met inclusion criteria, encompassing 67 patients. Most publications were single-patient case reports. Presentation occurred predominantly in newborns or early infancy. The dysraphic sac was lumbosacral in most cases, and type I split cord malformation with a bony spur outnumbered type II. Hemivertebrae and congenital scoliosis were the common vertebrae anomalies. Nearly all patients underwent surgery combining sac excision, detethering, and bony spur removal. Postoperative neurological outcomes were favorable: the majority improved, and the other ones remained stable; no surgery-related mortality was reported. HMM can be recognized as a distinct clinic radiological entity within the split-cord spectrum. Early, ideally prenatal diagnosis, timely microsurgical repair, and coordinated multidisciplinary care yield favorable functional outcomes in most patients. This first systematic review compiles the available evidence and provides a practical basis for future diagnostic and treatment decisions.