Tether pre-tension within vertebral body tethering reduces motion of the spine and influences coupled motion: a finite element analysis.

Anterior Vertebral Body Tethering (VBT) is a novel fusionless treatment option for selected adolescent idiopathic scoliosis patients which is gaining widespread interest. The primary objective of this study is to investigate the effects of tether pre-tension within VBT on the biomechanics of the spine including sagittal and transverse parameters as well as primary motion, coupled motion, and stresses acting on the L2 superior endplate. For that purpose, we used a calibrated and validated Finite Element model of the L1-L2 spine.

Posterior three-column osteotomies for the treatment of rigid thoracic kyphosis - a case series.

Objective: To evaluate the results and complications of a series of patients who underwent three-column osteotomy using the posterior approach for correction of complex cases of rigid dorsal kyphotic deformity.

Methods: Review of clinical records and images of 15 consecutive cases of pedicle subtraction osteotomies, bone-disk-bone osteotomies, or vertebral column resection, recording the etiology, type and level of osteotomy, extension of fixation, complications, and pre- and post-surgical measurements of the sagittal curves and pelvic parameters.

Results: Six pedicle subtraction osteotomies were performed, one of which in two adjacent vertebrae, as well as two bone-disk-bone osteotomies and seven vertebral column resection, two of which were performed in two adjacent vertebrae.