Individual measurement of normal sagittal curvature and its clinical application for thoracolumbar burst fractures

Abstract

Objective To explore the methods of measuring the normal sagittal curvature individually and its clinical application in the treatment of thoracolumbar burst fractures.Methods From June 2010 through January 2012,69 patient with thoracolumbar burst fracture were treated in our department.They were 41 men and 28 women,aged from 18 to 71 years (mean,39.3 years).Fracture levels:T11 in 6,T12in 22,L1 in 20,L2 in 12,L3 in 6,and L4 in 3 cases.The preoperative neural function by the American Spinal Injury Association (ASIA) system:grade A in 2,grade B in 4,grade C in 8,grade D in 20 and grade E in 35 cases.In the individualized surgical simulation before operation,the restored normal sagittal curvature of the patient was measured and the values were used for pre-bending of the connection rod.The compression ratio of anterior border heights of the injured vertebra,angle of sagittal curvature loss of the fixated segment and spinal canal compromise were recorded and compared preoperation,immediate post-operation and at the last follow-up.Results The operation time ranged from 100 to 200 minutes in this series (average,137minutes).All the patients were followed up for 12 to 25 months (average,14.3 months).There were significant differences between preoperation and postoperation regarding the compression ratio of anterior border heights of the injured vertebra,angle of sagittal curvature loss of the fixated segment and spinal canal compromise (P ＜ O.05),but no significant differences between immediate postoperation and last follow-up (P ＞ 0.05).There was no breakage of the pedicle screw or loosening of the implant.The neural malfunction did not deteriorate post-operation.All the 67 patients with incomplete paraplegia had more than one grade improvement in ASIA grading.Conclusions Individual measurement of normal sagittal curvature in a surgical simulation before operation can yield valuable values for prebending of the connection rod to facilitate better restoration of vertebral height and sagittal curvature in the treatment of thoracolumbar burst fracture.Recovery of normal sagittal curvature can significantly reduce loss of sagittal angle of the fixated segment and breakage and loosening of implants. Key words: Spinal injuries; Fracture; Imaging, three-dimensional; Sagittal plane curves; Surgical simulation