Biomechanical stability of transverse connectors in the setting of a thoracic pedicle subtraction osteotomy.

Background Context: Transverse connectors (TCs) are often used to improve the rigidity of posterior spinal instrumentation as previous investigations have suggested that TCs enhance torsional rigidity in long-segment thoracic constructs. Posterior osteotomies, such as pedicle subtraction osteotomy (PSO), are used in severe thoracic deformities and provide a significant amount of correction; as a consequence, however, PSOs also induce three-column spinal instability. In theory, augmentation of longitudinal constructs with TC after a thoracic PSO may provide additional rigidity, but the concept has not been previously evaluated.

Do stand-alone interbody spacers with integrated screws provide adequate segmental stability for multilevel cervical arthrodesis?

Background Context: Some postoperative complications after anterior cervical fusions have been attributed to anterior cervical plate (ACP) profiles and the necessary wide operative exposure for their insertion. Consequently, low-profile stand-alone interbody spacers with integrated screws (SIS) have been developed. Although SIS constructs have demonstrated similar biomechanical stability to the ACP in single-level fusions, their role as a stand-alone device in multilevel reconstructions has not been thoroughly evaluated.

The ventral lamina and superior facet rule: a morphometric analysis for an ideal thoracic pedicle screw starting point.

Background Context: With the increasing popularity of thoracic pedicle screws, the freehand technique has been espoused to be safe and effective. However, there is currently no objective, definable landmark to assist with freehand insertion of pedicle screws in the thoracic spine. With our own increasing surgical experience, we have noted a reproducible and unique anatomic structure known as the ventral lamina.

The biomechanical consequences of rod reduction on pedicle screws: should it be avoided?

Background Context: Rod contouring is frequently required to allow for appropriate alignment of pedicle screw-rod constructs. When residual mismatch is still present, a rod persuasion device is often used to achieve further rod reduction. Despite its popularity and widespread use, the biomechanical consequences of this technique have not been evaluated.

What is the best way to optimize thoracic kyphosis correction? A micro-CT and biomechanical analysis of pedicle morphology and screw failure.

Study Design: A human cadaveric biomechanical analysis.

Objective: The purpose of this study was to evaluate the bone density/trabecular width of the thoracic pedicle and correlate that with its resistance against compressive loading used during correction maneuvers in the thoracic spine (i.e.

The biomechanical effect of pedicle screw hubbing on pullout resistance in the thoracic spine.

Background Context: The biomechanical fixation strength afforded by pedicle screws has been strongly correlated with bone mineral density. It has been postulated that "hubbing" the head of the pedicle screw against the dorsal laminar cortex provides a load-sharing effect, thereby limiting cephalocaudad toggling and improving the pullout resistance of the pedicle screw.

Purpose: To evaluate the pullout strength (POS) of monoaxial hubbed pedicle screws versus standard fixation in the thoracic spine.

Structures at risk from pedicle screws in the proximal thoracic spine: computed tomography evaluation.

Background Context: Pedicle screw placement in the proximal thoracic spine may result in unwanted bicortical breach. An understanding of the potential structures at risk is paramount to safe screw placement.

Purpose: To assess the anatomic location of structures at risk with the placement of bicortical pedicle screw fixation in the proximal thoracic spine.

Does catastrophic midline failure of upper thoracic lamina screws violate the spinal canal? A cadaveric biomechanical analysis using two lamina screw techniques.

Background Context: Lamina screws have been reported to be a biomechanically sound alternative to pedicle screws in the proximal thoracic spine. However, concerns have been raised that midline failure may result in a spinal canal breach.

Purpose: To evaluate the catastrophic failure of proximal thoracic lamina screws using two techniques for lamina screw purchase.