Split cord malformation type I: Technical notes on the subject of a rare variant of a rare malformation

Abstract

Background: Split cord malformation type I is a rare form of occult spinal dysraphism. A median septum arising from vertebral arches is an exceedingly rare variant with only a few cases described. Methods: Description of clinical case and surgical technique. Results: We describe the case of a neurologically intact 2-year-old boy who was diagnosed with a split cord malformation type I. Radiological examination revealed an osseous septum in the vertebral canal arising from L2 and L3 arches and separating two independent hemicords. Septum removal, cord partial untethering and duramater reconstruction were performed without associated morbidity. The patient has been followed by a multidisciplinary team for five years. A subtle and non progressive left foot deformity was observed. We review practical aspects of the surgical treatment of this malformation. Conclusion: The diagnosis of associated vertebral malformations and tethering lesions is critical. Paramedian laminectomy, subperiosteal spur dissection and watertight reconstruction of posterior duramater represent important technical variations related to the posterior origin of the median septum.