Influence of vertebral column distraction on spinal cord volume: an experimental study in a goat model

Introduction Spinal cord injury may be related to excessive distraction of the spinal cord during surgical correction of spinal deformities by vertebral column resection. This study aimed to investigate how vertebral column distraction influences spinal cord volume to establish the safe range in a goat model. Materials and methods A vertebral column resection was performed on the tenth thoracic vertebra of 11 goats. The spinal cord was distracted until the somatosensory evoked potential signals were decreased to 50 % from baseline amplitude or were delayed by 10 % of the baseline peak latency. The osteotomy segment was stabilized with a PEEK mesh cage filled with bone graft, and the pedicle screws on the rods were then tightened in this position. Spinal cord volume was calculated using Mimics software, and T10 height, disk height, osteotomy segment height, and spinal segment height were measured using the MRI image workstation. Results Three goats were excluded, and data obtained from the eight remaining goats were analyzed. The safe limit of distraction distance was 11.8 ± 3.65 mm, and the distraction distance was strongly correlated with the difference between the pre- and postoperative measurements ( d value) of spinal cord volume per 1 mm of osteotomy segment height ( r = −0.952, p