Purpose of the study: Diastematomyelia is a rare spinal cord malformation defined as the presence of two separate spinal cords separated or not by an osseous, cartilaginous, or fibrous septum. Spinal malformations are almost always associated, raising difficult therapeutic challenges.
Material and method: We report three cases of congenital kyphoscoliosis associated with diastematomyelia in three girls aged 12, 14 and 15 years. The diastematomyelia was dorsal in one case, thoracolumbar in one and lumbar in the third. For all three patients, the indication for surgery was progression of the scoliosis with development of neurological signs of recent progressive aggravation. Preoperative distraction with a plaster cast was pursued for several months prior to posterior instrumentation. No attempt was made to correct the cord malformation nor achieve major correction of the spinal malformation. The instrumentation bridged the thoracolumbar scoliosis in one case and stopped above the malformation in the two others.
Results: The postoperative period was uneventful. There were no neurological complications. Preoperative neurological signs improved after surgery. Control radiographs showed an improvement in the deformity. At mean 6 years follow-up, these patients were not bothered in their everyday life. They had stable deformities which a globally balanced trunk. There were no signs of neurological evolution.
Discussion: The therapeutic strategy for diastematomyelia remains a subject of debate. For some authors, the spinal cord should be released systematically which for the majority, this is not necessary except if spinal distraction is planned or if there is a neurological problem. If there is an indication for spinal cord release, any spurs must be removed followed by the necessary dura mater plasty. In our three patients, and in agreement with the neurosurgery team, there was no need for neurosurgical release. The recent development of neurological deficits was explained by the important kyphosis rather by the intramedullary anomaly. Our therapeutic strategy thus focused on treatment of the scoliosis. This enabled us to stabilise the spine, protecting these patients from worsening neurological involvement and enabling good functional outcome. The zone of the malformation was not instrumented in all cases because the posterior arcs were deformed, but also to avoid compromising any future neurosurgical intervention.
