Evidence of invariant lower-limb kinematics in anticipation of ground contact during drop-landing and drop-jumping.

Gravity is a ubiquitous external force that must be considered when producing coordinated movements. Drop-landing is a popular task to study how humans cope with gravity, because anticipatory muscle activations can be released before the estimated ground contact. But the consequences of these anticipatory muscle activations have only been interpreted in terms of stiffening the lower-limbs in preparation for ground contact, without considering potential anticipatory kinematic consequences.

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.

Does IMU redundancy improve multi-body optimization results to obtain lower-body kinematics? A preliminary study says no.

Inertial Measurement Units (IMUs) have been proposed as an ecological alternative to optoelectronic systems for obtaining human body joint kinematics. Tremendous work has been done to reduce differences between kinematics obtained with IMUs and optoelectronic systems, by improving sensor-to-segment calibration, fusion algorithms, and by using Multibody Kinematics Optimization (MKO). However, these improvements seem to reach a barrier, particularly on transverse and frontal planes.

Analysis of the obstetrician's posture and movements during a simulated forceps delivery.

Background: The objective of this study was to identify and qualify, by means of a three-dimensional kinematic analysis, the postures and movements of obstetricians during a simulated forceps birth, and then to study the association of the obstetricians' experience with the technique adopted.

Method: Fifty-seven volunteer obstetricians, 20 from the Limoges and 37 from the Poitiers University hospitals, were included in this multi-centric study. They were classified into 3 groups: beginners, intermediates, and experts, beginners having performed fewer than 10 forceps deliveries in real conditions, intermediates between 10 and 100, and experts more than 100.

The Potential Role of Wearable Inertial Sensors in Laboring Women with Walking Epidural Analgesia.

There is a growing interest in wearable inertial sensors to monitor and analyze the movements of pregnant women. The noninvasive and discrete nature of these sensors, integrated into devices accumulating large datasets, offers a unique opportunity to study the dynamic changes in movement patterns during the rapid physical transformations induced by pregnancy. However, the final cut of the third trimester of pregnancy, particularly the first stage of labor up to delivery, remains underexplored.

Gait kinematics based on inertial measurement units with the sensor-to-segment calibration and multibody optimization adapted to the patient's motor capacities, a pilot study.

Introduction: Inertial Measurement Units (IMUs) offer a promising alternative to optoelectronic systems to obtain joint lower-limb kinematics during gait. However, the associated methodologies, such as sensor-to-segment (S2S) calibration and multibody optimization, have been developed mainly for, and tested on, asymptomatic subjects.

Research Question: This study proposes to evaluate two personalizations of the methodology used to obtain lower-body kinematics from IMUs with pathological subjects: S2S calibration and multibody optimization.

A new approach to assessing the obstetrician's posture and movement during an instrumental forceps delivery.

Introduction: The number of deliveries by forceps decreases significantly in favour of the vacuum. Now, when the use of forceps is necessary, physicians less experimented with this procedure are likely to induce serious and preventable perineal or foetal injuries. Training therefore becomes essential.

The contribution of multibody optimization when using inertial measurement units to compute lower-body kinematics.

Kinematics obtained using Inertial Measurement Units (IMUs) still present significant differences when compared to those obtained using optoelectronic systems. Multibody Optimization (MBO) might diminish these differences by reducing soft-tissue artefacts - probably emphasized when using IMUs - as established for optoelectronic-based kinematics. To test this hypothesis, 15 subjects were equipped with 7 IMUs and 38 reflective markers tracked by 18 optoelectronic cameras.

Inhibition of the CCR6-CCL20 axis prevents regulatory T cell recruitment and sensitizes head and neck squamous cell carcinoma to radiation therapy.

Background:  Radioresistance of HNSCCs remains a major challenge for effective tumor control. Combined radiotherapy (RT) and immunotherapy (IT) treatment improved survival for a subset of patients with inflamed tumors or tumors susceptible to RT-induced inflammation. To overcome radioresistance and improve treatment outcomes, an understanding of factors that suppress anti-tumor immunity is necessary.

Detection of Horse Locomotion Modifications Due to Training with Inertial Measurement Units: A Proof-of-Concept.

Detecting fatigue during training sessions would help riders and trainers to optimize their training. It has been shown that fatigue could affect movement patterns. Inertial measurement units (IMUs) are wearable sensors that measure linear accelerations and angular velocities, and can also provide orientation estimates.

Translaryngeal ultrasound in thyroid surgery: state of the art review.

Background: Clinical voice assessment prior to thyroid and parathyroid surgery is essential, but the paradigm of indirect laryngoscopy (IDL), when indicated, has been challenged by the risk of aerosolised SARS-Cov-2 during endoscopy of the aerodigestive tract. Translaryngeal ultrasound (TLUS) to assess the vocal cords has been proposed as a safe, non-invasive and sensitive alternative. The aim of this review was to verify TLUS as a viable tool for perioperative laryngeal assessment.

Avoidance of primary site adjuvant radiotherapy following transoral robotic surgery: a cohort study.

Background: Post-operative radiotherapy (PORT) volumes and dose to target structures likely influence swallowing function and quality of life following transoral robotic surgery (TORS). The aim of this study is to analyse disease control and swallowing outcomes in patients undergoing TORS for oropharyngeal squamous cell carcinoma (OPSCC) to determine the impact of omitting the primary site from the PORT treatment volume.

Methods: Prospectively collected data from patients that underwent TORS between March 2013 and April 2021 were reviewed.

Cervicofacial and mediastinal emphysema following minor dental procedure: a case report and review of the literature.

Background: Subcutaneous cervical emphysema is a clinical sign associated with many conditions, including laryngotracheal trauma, pneumothorax and necrotizing deep tissue infections.

Case Presentation: We discuss a case of a 76-year-old man presenting with extensive cervical emphysema a few hours after a minor dental filling procedure. The CT-scan revealed a significant amount of air within the cervical and mediastinal spaces, reaching lobar bronchi.

Sensor-to-Segment Calibration Methodologies for Lower-Body Kinematic Analysis with Inertial Sensors: A Systematic Review.

Kinematic analysis is indispensable to understanding and characterizing human locomotion. Thanks to the development of inertial sensors based on microelectronics systems, human kinematic analysis in an ecological environment is made possible. An important issue in human kinematic analyses with inertial sensors is the necessity of defining the orientation of the inertial sensor coordinate system relative to its underlying segment coordinate system, which is referred to sensor-to-segment calibration.

Using accelerations of single inertial measurement units to determine the intensity level of light-moderate-vigorous physical activities: Technical and mathematical considerations.

Quantifying physical activity and estimating the metabolic equivalent of tasks based on inertial measurement units has led to the emergence of multiple methods and data reduction approaches known as physical activity metrics. The present study aims to compare those metrics and reduction approaches based on descriptive and high order statistics. Data were obtained from 147 young healthy subjects wearing inertial measurement units at their wrist or ankle during standing, walking and running, labeled as light, medium or vigorous activities.

Does the McRoberts' manoeuvre need to start with thigh abduction? An innovative biomechanical study.

Background: Guidelines and description about the achievement of the McRoberts manoeuvre are discordant, particularly concerning the need for abduction before the beginning of the manoeuvre. We sought to compare the biomechanical efficiency of the McRoberts' manoeuvre, with and without thigh abduction.

Methods: In a postural comparative study, twenty-three gravidas > 32 weeks of gestational age and not in labour were assessed during three repetitions of two McRoberts' manoeuvre that differed in terms of starting position.

Biomechanical comparison of squatting and "optimal" supine birth positions.

In obstetric science, it is unknown whether the inherent biomechanical features of the squatting position can be achieved and/or transposed to the supine birth position. In this study Biomechanical features of the squatting position were compared with 2 hyperflexed supine positions for giving birth. Thirteen pregnant women past the 32 weeks of gestational age not in labor were assessed first in the squatting position with the feet flat on the floor, then in the hyperflexed supine position, and finally in the optimal supine position "crushing" the hand of the caregiver onto the bed.

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.

Assessment of Pelvic-Lumbar-Thigh Biomechanics to Optimize The Childbirth Position: An "In Vivo" Innovative Biomechanical Study.

The study aimed to assess the associations between the pelvis orientation, lumbar curve and thigh postures throughout pregnancy in a population of healthy women. Additionally, optimal mechanical birth conditions in terms of the pelvic inlet and lumbar curve were researched. The individuals' posture was assessed with three-dimensional motion analysis and the lumbar curve with the Epionics SPINE system.

Is there an impact of feet position on squatting birth position? An innovative biomechanical pilot study.

Background: The squatting birth position is widely used for "natural" birth or in countries where childbirth occurs in non-medical facilities. Squatting birth positions, like others, are roughly defined so a biomechanical assessment is required with the availability of noninvasive technology in pregnant women. In practice, we can observe spontaneously two kinds of squatting birth position: on tiptoes and with feet flat.

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.