Diastematomyelia in Adults

Diastematomyelia is a congenital malformation in which a band of fibrous or bony tissue extends dorsoventrally through the spinal canal and between the portions of either a partially duplicated or split spinal cord. According to Bremer (2), this represents one manifestation of a persistent accessory neurenteric canal or dorsal intestinal fistula. These fistulas, which in the embryo extend from the enteric cavity to the neural groove, may persist and present clinically as tubular tracts reaching from some portion of the gastrointestinal tract to the skin (7, 9). Others may form cysts and be mistaken for anterior meningoceles or branchial cysts (2). More commonly the fistula disappears, but according to Bremer its former presence may be manifested by: increased breadth of the vertebral bodies; a circular or oval defect extending through the vertebral bodies; development of the vertebra in two halves, which later fuse to form a median bony or cartilaginous spur projecting into the spinal canal and transfixing the spinal cord; a fibrous cord formed by a remaining fragment of the fistula, attached to an inconspicuous midline cutaneous dimple. Bremer's explanation is that the two halves of the spinal cord, which have been separated in a widened spinal canal by the bony or cartilaginous spur, do not attempt to reunite after the fistula disappears but are invested by meninges and continue their development either as the two lateral halves of a spinal cord (diastematomyelia) or as a pair of malformed whole cords (diplomyelia). He feels that these indications of a former median cleft both in the spinal cord and vertebra offer definite proof of the earlier presence of an accessory dorsal intestinal fistula. This malformation was first described in 1837, and in 1940 Herren and Edwards (6) were able to collect 42 cases from the literature. It was not until 1950 that clinical interest was aroused by the report of Neuhauser, Wittenborg and Dehlinger (I3). They described 12 cases, in 10 of which a correct preoperative diagnosis was made. Since their report several additional examples have appeared in the medical literature (1, 3, 4,8, 15, 16). All of the patients in whom a diagnosis is reported to have been made during life have been children, with the exception of a twenty-year-old female described by Hamby (5) . We are presenting here 2 examples in adults aged twenty and thirty-nine years. In the older patient diastematomyelia was correctly diagnosed preoperatively. Case I: E. B. H., a 39-year-old white male, sought medical advice because of numbness in the medial aspect of both thighs for the past six months, occasionally associated with paresthesia. The patient was a pharmacist, who worked in a standing position eleven hours daily, seven days a week, with only slight difficulty.