MRI delineation of the morphometric characteristics of type I split cord malformations: a retrospective analysis of 29 cases

Objective: The purpose of this study was to elucidate the morphometric characteristics by magnetic resonance imaging (MRI) of type I split cord malformation (SCM) patients.Methods: All subjects received conventional MRI with the Achieva 3.0T system (Philips Healthcare, Andover, MA, USA), including T1WI/axial and sagittal T2WI/axial FLAIR. Transverse diameter (TD) and sagittal diameter (SD) of the split cord, TD of the convex (TDconvex) and the concave (TDconcave), cranial SD (SDcranial), and caudal SD (SDcaudal) were recorded on the sagittal image combined with the two-dimensional view. Statistical comparison was performed within and between the groups.Results: Twenty-nine type I SCM patients were included, 24 (82.8%) of whom had scoliosis. Mean TD and SD of the split cord were 0.55±0.31 cm and 7.52±4.03 cm, respectively. No statistically significant difference was observed in TD, SD, and other parameters among the 3 groups. However, mean TD of the split cord in type I SCM patients with congenital scoliosis (0.49±0.29 cm) was significantly greater than in those without congenital scoliosis (0.18±0.44 cm) (p<0.05). TDconvex was significantly smaller than TDconcave in type I SCM patients with congenital scoliosis (p<0.05). Additionally, there was no statistically significant difference between SDcranial and SDcaudal in type I SCM patients with congenital scoliosis (p>0.05); however, SDcranial was significantly smaller than SDcaudal in Group 2.Conclusion: Our study provides the first MRI characterization of the morphometric features of type I SCM, and our findings will help orthopedic surgeons in better navigating the surgical field in corrective surgery of congenital scoliosis of type I SCM patients.

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