Composite type split cord malformation: a two-center study and analysis of a series of 25 cases

Split cord malformation (SCM) is a type of congenital spinal dysraphism characterized by the development of a split spinal cord separated by either a bony septum or a membranous/fibrous septum. The presence of two distinct SCMs in the same patient, with segments of normal cord interposed between them, is referred to as a composite-type SCM. This study aims to evaluate the variations of composite-type SCMs, which have been reported only at the case-report level in the literature, and to present the challenges encountered in surgical technique.

The study included 25 patients who underwent surgery for composite-type SCM at two centers. The mean age was 37.48 months. Sixty-four percent of the patients were female. The most common presenting findings were cutaneous stigmata, kyphoscoliosis, and gait disturbances.The most frequent location was the thoracolumbar region. Among the patients, 20% had Type 1 + Type 2 SCM, 12% had Type 1 + Type 1.5, and 68% had Type 1 + Type 1. The most commonly affected vertebrae were between T8 and T11.

The demographic characteristics of composite SCMs were found to be similar to those of classical SCMs. However, cutaneous findings and kyphoscoliosis were more frequently observed in composite SCMs. In terms of localization, composite SCMs tended to occur at higher spinal levels and were more commonly found in the thoracic-thoracolumbar regions compared to classical SCMs. Intraoperative complications related to prolonged operative time and increased risk of bleeding should be anticipated and addressed in the preoperative period. Surgical planning should prioritize starting from the upper SCM, with the final step being the transection of the filum terminale.