Iatrogenic vertebral fracture in ankylosed spine during liver transplantation: a case report and biomechanical study using finite element method.

Purpose: The occurrence of an iatrogenic vertebral fracture during non-spinal digestive surgery is an exceptional event that has not been previously documented. Our study aims to explain the occurrence of this fracture from a biomechanical perspective, given its rarity. Using a finite element model of the spine, we will evaluate the strength required to induce a vertebral fracture through a hyperextension mechanism, considering the structure of the patient's spine, whether it is ossified or healthy.

Spinal Fractures during Touristic Motorboat Sea Cruises: An Underestimated and Avoidable Phenomenon.

Purpose: Each summer, many vacationers enjoy the Mediterranean Sea shores. Among the recreational nautical activities, motorboat cruise is a popular choice that leads to a significant number of thoracolumbar spine fractures at our clinic. This phenomenon seems to be underreported, and its injury mechanism remains unclear.

When epidemiological databases inform injury mechanisms: biomechanical analysis of injury associations.

Background: Vehicle accidents are still a heavy social burden despite improvements due the latest technologies and policies. To pursue the trend of decrease, having a more detailed view and understanding of the injury patterns would contribute to inform both the rescue team to optimize victim's management and policymakers in order for them to tackle at best this issue.

Methods: Two complementary analyses of injury associations were performed, one using a biomechanical classification and the other an anatomic one, computed on data stratified by car accident type (lateral or frontal).

An Ex Situ Cadaver Liver Training Model Continuously Pressurized to Simulate Specific Skills Involved in Laparoscopic Liver Resection: the Lap-Liver Trainer.

Background: Laparoscopic liver resection (LLR) requires delicate skills. The aim of the study was to develop a training model mimicking as much as possible intraoperative bleeding and bile leakage during LLR. We also assessed the educational value of the training model.

Head-ground impact conditions and helmet performance in E-scooter falls.

Objective: Head injuries are common injuries in E-scooter accidents which have dramatically increased in recent years. The head impact conditions and helmet performance during E-scooter accidents are barely investigated. This study aims to characterize the head-ground impact biomechanics and evaluate bicycle helmet protection in typical E-scooter falls.

Biomechanical evaluation of Back injuries during typical snowboarding backward falls.

To prevent spinal and back injuries in snowboarding, back protector devices (BPDs) have been increasingly used. The biomechanical knowledge for the BPD design and evaluation remains to be explored in snowboarding accident conditions. This study aims to evaluate back-to-snow impact conditions and the associated back injury mechanisms in typical snowboarding backward falls.

Cervical spine injury response to direct rear head impact.

Background: Direct rear head impact can occur during falls, road accidents, or sports accidents. They induce anterior shear, flexion and compression loads suspected to cause flexion-distraction injuries at the cervical spine. However, post-mortem human subject experiments mostly focus on sled impacts and not direct head impacts.

Experimental Bi-axial tensile tests of spinal meningeal tissues and constitutive models comparison.

Introduction This study aims at identifying mechanical characteristics under bi-axial loading conditions of extracted swine pia mater (PM) and dura and arachnoid complex (DAC). Methods 59 porcine spinal samples have been tested on a bi-axial experimental device with a pre-load of 0.01 N and a displacement rate of 0.

Numerical Investigation of Spinal Cord Injury After Flexion-Distraction Injuries at the Cervical Spine.

Flexion-distraction injuries frequently cause traumatic cervical spinal cord injury (SCI). Post-traumatic instability can cause aggravation of the secondary SCI during patient care. However, there is little information on how the pattern of disco-ligamentous injury affects the SCI severity and mechanism.

Biomechanical analysis of the number of implants for the immediate sacroiliac joint fixation.

Purpose: The fusion of the sacroiliac joint (SIJ) is the last treatment option for chronic pain resulting from sacroiliitis. With the various implant systems available, there are different possible surgical strategies in terms of the type and number of implants and trajectories. The aim was to quantify the effect of the number of cylindrical threaded implants on SIJ stabilization.

About some factors influencing safety mattress performances in head impact collisions: A pilot study.

Objectives: In recreational snow sports activities, safety mattresses are placed on obstacles to prevent injuries from a collision with users. However, the performances of these devices in field conditions remain unclear. The objective of this study is to evaluate the effect of mattress thickness, impact speed, impacting mass and atmospheric conditions on head acceleration during an in-field impact on safety mattress.

Instrumentation of the sacroiliac joint with cylindrical threaded implants: A detailed finite element study of patient characteristics affecting fixation performance.

The sacroiliac joint (SIJ) is a known pain generator that, in severe cases, may require surgical fixation to reduce intra-articular displacements and allow for arthrodesis. The objective of this computational study was to analyze how the number of implants affected SIJ stabilization with patient-specific characteristics such as the pelvic geometry and bone quality. Detailed finite element models were developed to account for three pelvises of differing anatomy.

Tensile mechanical properties of the cervical, thoracic and lumbar porcine spinal meninges.

Background: The spinal meninges play a mechanical protective role for the spinal cord. Better knowledge of the mechanical behavior of these tissues wrapping the cord is required to accurately model the stress and strain fields of the spinal cord during physiological or traumatic motions. Then, the mechanical properties of meninges along the spinal canal are not well documented.

Biomechanical comparison of spinal cord compression types occurring in Degenerative Cervical Myelopathy.

Background: Degenerative Cervical Myelopathy results from spine degenerations narrowing the spinal canal and inducing cord compressions. Prognosis is challenging. This study aimed at simulating typical spinal cord compressions observed in patients with a realistic model to better understand pathogenesis for later prediction of patients' evolution.

The predictive capacity of the MADYMO ellipsoid pedestrian model for pedestrian ground contact kinematics and injury evaluation.

Pedestrian injuries occur in both the primary vehicle contact and the subsequent ground contact. Currently, no ground contact countermeasures have been implemented and no pedestrian model has been validated for ground contact, though this is needed for developing future ground contact injury countermeasures. In this paper, we assess the predictive capacity of the MADYMO ellipsoid pedestrian model in reconstructing six recent pedestrian cadaver ground contact experiments.

A Framework of a Lower Limb Musculoskeletal Model With Implemented Natural Proprioceptive Feedback and Its Progressive Evaluation.

Objective: Proprioceptive senses play an important role in human body reflex and movement, so far implementing physiological mathematical models of proprioceptors in the musculoskeletal model and investigating their effects have not been sufficiently investigated. The purpose of the present study was to establish a compact framework for a lower limb musculoskeletal model by considering both ascending signals from central nervous system and descending feedback neural signal from physiologically realistic proprioceptors and evaluate it with progressive experimental data as well as investigating the effects of the proprioceptive feedback on the human movement.

Methods: The simulation framework was established by combining a lower limb musculoskeletal model, the forward dynamic tool from OpenSim codes, and an executive program based on Python codes.

Contribution of injured posterior ligamentous complex and intervertebral disc on post-traumatic instability at the cervical spine.

Posterior ligamentous complex (PLC) and intervertebral disc (IVD) injuries are common cervical spine flexion-distraction injuries, but the residual stability following their disruption is misknown. The objective of this study was to evaluate the effect of PLC and IVD disruption on post-traumatic cervical spine stability under low flexion moment (2 Nm) using a finite element (FE) model of C2-T1. The PLC was removed first and a progressive disc rupture (one third, two thirds and complete rupture) was modeled to simulate IVD disruption at C2-C3, C4-C5 and C6-C7.

Effect of experimental, morphological and mechanical factors on the murine spinal cord subjected to transverse contusion: A finite element study.

Finite element models combined with animal experimental models of spinal cord injury provides the opportunity for investigating the effects of the injury mechanism on the neural tissue deformation and the resulting tissue damage. Thus, we developed a finite element model of the mouse cervical spinal cord in order to investigate the effect of morphological, experimental and mechanical factors on the spinal cord mechanical behavior subjected to transverse contusion. The overall mechanical behavior of the model was validated with experimental data of unilateral cervical contusion in mice.

Cervical Canal Morphology: Effects of Neck Flexion in Normal Condition: New Elements for Biomechanical Simulations and Surgical Management.

Study Design: Continuous measurements and computation of absolute metrics of cervical subarachnoid space (CSS) and spinal cord (SC) geometries proposed are based on in vivo magnetic resonance imaging and 3D reconstruction.

Objective: The aim of the study is to offer a new methodology to continuously characterize and to quantify the detailed morphology of the CSS and the cervical SC in 3D for healthy subjects in both neutral supine and flexion.

Summary Of Background Data: To the best of our knowledge, no study provides a morphological quantification by absolute indices based on the 3D reconstruction of SC and CSS thanks to in vivo magnetic resonance imaging.

Biomechanical analysis of two insertion sites for the fixation of the sacroiliac joint via an oblique lateral approach.

Background: The sacroiliac joint is an important source of low back pain. In severe cases, sacroiliac joint fusion is used to reduce pain, but revision rates can reach 30%. The lack of initial mechanical stability may lead to pseudarthrosis, thus not alleviating the patient's symptoms.

Biomechanical analysis of segmental lumbar lordosis and risk of cage subsidence with different cage heights and alternative placements in transforaminal lumbar interbody fusion.

Cage subsidence in transforaminal lumbar interbody fusion (TLIF) is one of the concerns. The objective was to numerically assess the resulting segmental lumbar lordosis (SLL) and stresses at the bone-cage interface as functions of cage height (8- vs. 10-mm) and cage placement (oblique asymmetric, vs.

Descriptive analysis of the effect of back protector on the prevention of vertebral and thoracolumbar injuries in serious motorcycle accident.

Context And Objective: Among the different products and protective gear used by riders of two-wheeled motorized vehicles, back protectors that are designed to prevent damage to the spinal column are widely used today compared other protections. However, few studies measure their effectiveness. Can their effectiveness be measured? How do they help decrease or change the nature of thoracolumbar traumas that occur? To address these questions and remedy the lack of objective data regarding these products, an epidemiological, clinical, and biomechanical analysis of motorcycle riders who were admitted to a French trauma center after an accident was performed.

Traumatic Spinal Cord Injuries with Fractures in a Québec Level I Trauma Center.

Background: Traumatic spinal cord injuries (TSCI) have devastating consequences on patients' quality of life. More specifically, TSCI with spinal fractures (TSCIF) have the most severe neurological impairment, although limited data are available. This study aimed at providing data and analyzing TSCIF in a level I trauma center in the province of Québec, Canada.