Finite element analysis part 2 of 2: Glenohumeral bone stress distribution depends on implant configuration for anatomic and reverse stemless shoulder implants.

Purpose: Our purpose was to quantify stresses in the bone surrounding stemless implants in various configurations.

Methods: A detailed finite element model of the glenohumeral joint was used to simulate abduction kinematics before and after arthroplasty and to measure bone stresses around the implants. Two digital patients were simulated: one healthy and one with supraspinatus muscle impairment (deficiency).

Finite element analysis part 1 of 2: Influence of short stem implant polyethylene configuration on glenohumeral joint biomechanics.

Purpose: Stress shielding in short-stem arthroplasty can cause critical metaphyseal bone loss. If the size and shape of the humeral shaft are important factors, it is unknown whether the shape of the polyethylene component in reverse shoulder arthroplasty (RSA) affects bone stress around or within the stem. We explored the impact of polyethylene shape on humeral and scapular stress distribution using a finite element model.

Biomechanical comparison of sacral and transarticular sacroiliac screw fixation.

Study Design: A detailed finite element analysis of screw fixation in the sacrum and pelvis.

Objective: To biomechanically assess and compare the fixation performance of sacral and transarticular sacroiliac screws. Instrumentation constructs are used to achieve fixation and stabilization for the treatment of spinopelvic pathologies.

Effect of impact velocity and ligament mechanical properties on lumbar spine injuries in posterior-anterior impact loading conditions: a finite element study.

Traumatic events may lead to lumbar spine injuries ranging from low severity bony fracture to complex fracture dislocation. Injury pathomechanisms as well as the influence of loading rate and ligament mechanical properties were not yet fully elucidated. The objective was to quantify the influence of impact velocity and ligament properties variability on the lumbar spine response in traumatic flexion-shear conditions.

Biomechanical Analysis of Acute Proximal Junctional Failure After Surgical Instrumentation of Adult Spinal Deformity: The Impact of Proximal Implant Type, Osteotomy Procedures, and Lumbar Lordosis Restoration.

Study Design: Computer biomechanical simulations to analyze risk factors of proximal junctional failure (PJF) following adult scoliosis instrumentation.

Objective: To evaluate the biomechanical effects on the proximal junctional spine of the proximal implant type, tissue dissection, and lumbar lordosis (LL) restoration.

Summary Of Background Data: PJF is a severe proximal junctional complication following adult spinal instrumentation requiring revision surgery.

Biomechanical analysis of proximal junctional failure following adult spinal instrumentation using a comprehensive hybrid modeling approach.

Background: Proximal junctional failure is a severe proximal junctional complication following adult spinal instrumentation and involving acute proximal junctional kyphotic deformity, mechanical failure at the upper instrumented vertebra or just above, and/or proximal junctional osseoligamentous disruption. Clinical studies have identified potential risk factors, but knowledge on their biomechanics is still lacking for addressing the proximal junctional failure issues. The objective of this study was to develop comprehensive computational modeling and simulation techniques to investigate proximal junctional failure.

Finite Element Analysis of Sacroiliac Joint Fixation under Compression Loads.

Background: Sacroiliac joint (SIJ) is a known chronic pain-generator. The last resort of treatment is the arthrodesis. Different implants allow fixation of the joint, but to date there is no tool to analyze their influence on the SIJ biomechanics under physiological loads.

Strain rate dependent behavior of the porcine spinal cord under transverse dynamic compression.

The accurate description of the mechanical properties of spinal cord tissue benefits to clinical evaluation of spinal cord injuries and is a required input for analysis tools such as finite element models. Unfortunately, available data in the literature generally relate mechanical properties of the spinal cord under quasi-static loading conditions, which is not adapted to the study of traumatic behavior, as neurological tissue adopts a viscoelastic behavior. Thus, the objective of this study is to describe mechanical properties of the spinal cord up to mechanical damage, under dynamic loading conditions.

Morphometrics of the entire human spinal cord and spinal canal measured from in vivo high-resolution anatomical magnetic resonance imaging.

Study Design: Measurements of cervical and thoracolumbar human spinal cord (SC) geometry based on in vivo magnetic resonance imaging and investigation of morphological "invariants."

Objective: The current work aims at providing morphological features of the complete in vivo human normal SC and at investigating possible "invariant" parameters that may serve as normative data for individualized study of SC injuries.

Summary Of Background Data: Few in vivo magnetic resonance image-based studies have described human SC morphology at the cervical level, and similar description of the entire SC only relies on postmortem studies, which may be prone to atrophy biases.

Biomechanics of thoracolumbar junction vertebral fractures from various kinematic conditions.

Thoracolumbar spine fracture classifications are mainly based on a post-traumatic observation of fracture patterns, which is not sufficient to provide a full understanding of spinal fracture mechanisms. This study aimed to biomechanically analyze known fracture patterns and to study how they relate to fracture mechanisms. The instigation of each fracture type was computationally simulated to assess the fracture process.