Anterior Fixation of Floating Facet Fractures in the Cervical Spine: A Prospective Case Series and Biomechanical Analysis.

Background: Unilateral fractures involving complete separation of the lateral mass from the vertebra and lamina (floating lateral mass fractures) are a unique subset of cervical spine fractures. These injuries are at significant risk for displacement without operative fixation. Posterior fixation has proven to facilitate adequate fusion.

An In Vitro Evaluation of Fracture Reduction Achieved by Inflatable Bone Tamps Under Simulated Physiological Load.

Study Design: An in vitro biomechanical study.

Objective: To determine the fracture reduction achieved by a novel inflatable bone tamp under simulated physiological load.

Summary Of Background Data: Previous biomechanical studies have showed that kyphoplasty allows near-total restoration of lost vertebral height in unloaded conditions and partial height restoration under simulated physiological loads.

Axial pullout strength comparison of different screw designs: fenestrated screw, dual outer diameter screw and standard pedicle screw.

Background: The pullout strength of pedicle screws is influenced by many factors, including diameter of the screws, implant design, and augmentation with bone cement such as PMMA. In the present study, the pullout strength of an innovative fenestrated screw augmented with PMMA was investigated and was compared to unaugmented fenestrated, standard and dual outer diameter screw.

Methods: Twenty four thoracolumbar vertebrae (T10-L5, age 60 to 70 years) from three cadavers were implanted with the four different pedicle screws.

Additional sagittal correction can be obtained when using an expandable titanium interbody device in lumbar Smith-Peterson osteotomies: a biomechanical study.

Background Context: Insertion of intervertebral fusion devices between consecutive Smith-Peterson osteotomies (SPOs) provides an anterior fulcrum during compression, which has been documented to improve achievable Cobb angle correction. Extension of these principles to an expandable device would theoretically provide greater surgical adjustment for flatback and scoliotic cases than a static cage.

Purpose: To investigate whether an expandable titanium interbody device would produce greater sagittal correction than a static spacer when used during SPO procedures.

Pedicle Screw Configuration for Thoracolumbar Burst Fracture Treatment: Short versus Long Posterior Fixation Constructs with and without Anterior Column Augmentation.

Study Design: An in-vitro study.

Purpose: The current study is aimed at investigating the differences in stability between short posterior fixation (SPF), hybrid posterior fixation (HPF), and long posterior fixation (LPF) with and without anterior column augmentation using calcium phosphate bone cement (CaP) for treating burst fractures (BFs).

Overview Of Literature: The ideal treatment for thoracolumbar BF is controversial regarding the use of short or LPF constructs.

Comparison of fatigue strength of C2 pedicle screws, C2 pars screws, and a hybrid construct in C1-C2 fixation.

Study Design: A biomechanical study comparing the fatigue strength of different types of C2 fixation in a C1-C2 construct.

Objective: To determine the pullout strength of a C2 pedicle screw and C2 pars screw after cyclical testing and differentiate differences in stiffness pre- and post-cyclical loading of 3 different C1-C2 fixations.

Summary Of Background Data: Some surgeons use a short C2 pars screw in a C1-C2 construct, because it is less technically demanding and/or when the vertebral artery is high riding.

In vitro biomechanical study to quantify range of motion, intradiscal pressure, and facet force of 3-level dynamic stabilization constructs with decreased stiffness.

Study Design: An in vitro biomechanical study.

Objective: To perform in vitro biomechanical testing on a lumbar spine using a 6-degree-of-freedom machine. To compare the range of motion (ROM), intradiscal pressure, and facet force of different 3-level dynamic stabilization constructs with traditional rigid constructs.

Biomechanical evaluation of a novel posterior integrated clamp that attaches to an existing posterior instrumentation for use in thoracolumbar revision.

Study Design: An in vitro biomechanical study.

Purpose: To evaluate the biomechanics of a novel posterior integrated clamp (IC) that extends on an already implanted construct in comparison to single long continuous bilateral pedicle screw (BPS) and rod stabilization system.

Overview Of Literature: Revision surgery in the thoracolumbar spine often necessitates further instrumentation following a failed previous back surgery.

Biomechanical comparison of spinopelvic reconstruction techniques in the setting of total sacrectomy.

Study Design: An in vitro biomechanical study.

Objective: To biomechanically test and evaluate 4 different methods of spinopelvic reconstruction techniques and determine the most biomechanically stable construct for stabilization of the spinopelvic junction after total sacrectomy.

Summary Of Background Data: Total sacrectomy is necessary to treat a sacral tumor when it involves the S1 vertebra.

Kinematics of a selectively constrained radiolucent anterior lumbar disc: comparisons to hybrid and circumferential fusion.

Background: Despite encouraging clinical outcomes of one-level total disc replacements reported in literature, there is no compelling evidence regarding the stability following two-level disc replacement and hybrid constructs. The current study is aimed at evaluating the multidirectional kinematics of a two-level disc arthroplasty and hybrid construct with disc replacement adjacent to rigid circumferential fusion, compared to two-level fusion using a novel selectively constrained radiolucent anterior lumbar disc.

Methods: Nine osteoligamentous lumbosacral spines (L1-S1) were tested in the following sequence: 1) Intact; 2) One-level disc replacement; 3) Hybrid; 4) Two-level disc replacement; and 5) Two-level fusion.

A comparative biomechanical study of a novel integrated plate spacer for stabilization of cervical spine: an in vitro human cadaveric model.

Background: Integrated plate-spacer may provide adequate construct stability while potentially lowering operative time, decreasing complications, and providing less mechanical obstruction. The purpose of the current study was to compare the biomechanical stability of an anatomically profiled 2-screw integrated plate-spacer to a traditional spacer only and to a spacer and anterior cervical plate construct. In addition, the biomechanical stability of 2-screw integrated plate-spacer was compared to a commercially available 4-screw integrated plate-spacer.

Pedicle screw instrumentation of thoracolumbar burst fractures: Biomechanical evaluation of screw configuration with pedicle screws at the level of the fracture.

Background: Posterior fixation alone may not be adequate to achieve and maintain burst fracture reduction. Adding screws in the fractured body may improve construct stiffness. This in vitro study evaluates the biomechanical effect of inserting pedicle screws in the fractured body compared with conventional short- and long-segment posterior fixation.

Cyclic loads do not compromise functionality of the interspinous spacer or cause damage to the spinal segment: an in vitro analysis.

Study Design: A biomechanical study to evaluate the effects of interspinous spacer under cyclic complex loading.

Objectives: To determine the risk of device migration and to assess damage on the device and specimen under extreme coupled motion. Another objective was to evaluate the effect on vertebral foramen and canal dimensions after spacer implantation.