Neurosurgical treatment in elderly patients with Traumatic brain injury: A 20-year follow-up study.

Introduction: Traumatic brain injury in the elderly population can have a substantial impact on patients' quality of life. In this regard, successful treatment strategies are hard to define to date.

Research Question: In order to facilitate further insight, this study assessed outcomes following acute subdural hematoma evacuation in patients aged ≥65 years in a large patient series.

Profound prospective assessment of radiological and functional outcome 6 months after TBI in elderly.

Background: Recovery after traumatic brain injury (TBI) in older adults is usually affected by the presence of comorbidities, leading to more severe sequelae in this age group than in younger patients. However, there are only few reports that prospectively perform in-depth assessment of outcome following TBI in elderly.

Objective: This study aims at documenting structural brain characteristics and functional outcome and quality of life in elderly patients 6 months after TBI and comparing these data with healthy volunteers undergoing the same assessments.

Probabilistic planning for ligament-balanced TKA-Identification of critical ligament properties.

Total knee arthroplasty (TKA) failures are often attributed to unbalanced knee ligament loading. The current study aims to develop a probabilistic planning process to optimize implant component positioning that achieves a ligament-balanced TKA. This planning process accounts for both subject-specific uncertainty, in terms of ligament material properties and attachment sites, and surgical precision related to the TKA process typically used in clinical practice.

Maximal lateral ligament strain and loading during functional activities: Model-based insights for ankle sprain prevention and rehabilitation.

Background: Although it is generally accepted that sports activities present a high risk of lateral ligament injury, the extent to which ligaments are loaded during functional activities is less explored. This is relevant when considering ankle sprain prevention and staged rehabilitation following ligament sprain or reinforcing surgery. Therefore, anterior talofibular ligament, calcaneofibular ligament and posterior talofibular ligament strain and loading were evaluated, based on a newly developed loading index, during movements executed during daily life and rehabilitation.

Computationally Efficient Optimization Method to Quantify the Required Surgical Accuracy for a Ligament Balanced TKA.

Objective: This study proposes a computationally efficient method to quantify the effect of surgical inaccuracies on ligament strain in total knee arthroplasty (TKA). More specifically, this study describes a framework to determine the implant position and required surgical accuracy that results in a ligament balanced post-operative outcome with a probability of 90%.

Methods: The response surface method is used to translate uncertainty in the implant position parameters to uncertainty in the ligament strain.

Evaluation of Patient-Specific Cranial Implant Design Using Finite Element Analysis.

Background: Various studies have investigated the load-bearing capacity of patient-specific cranial implants. However, little attention has been given to the evaluation of the design of ceramic-titanium (CeTi) implants.

Methods: A biomechanical evaluation of 3 patient-specific cranial implants was performed using finite element analysis.

Skull fracture prediction through subject-specific finite element modelling is highly sensitive to model parameters.

Reliable computer models are needed for a better understanding of the physical mechanisms of skull fracture in accidental hits, falls, bicycle - motor vehicle & car accidents and assaults. The performance and biofidelity of these models depend on the correct anatomical representation and material description of these structures. In literature, a strain energy criterion has been proposed to predict skull fractures.

The sensitivity to inter-subject variability of the bridging vein entry angles for prediction of acute subdural hematoma.

Acute subdural hematoma (ASDH) is one of the most frequent traumatic brain injuries (TBIs) with high mortality rate. Bridging vein (BV) ruptures is a major cause of ASDH. The KTH finite element head model includes bridging veins to predict acute subdural hematoma due to BV rupture.

Anatomical Variation of the Tibia - a Principal Component Analysis.

Conventional anatomically contoured plates do not adequately fit most tibiae. This emphasizes the need for a more thorough morphological study. Statistical shape models are promising tools to display anatomical variations within a population.

Modal frequency and shape curvature as a measure of implant fixation: A computer study on the acetabular cup.

Modal parameters are often investigated in order to assess the initial fixation of an implant. Most of studies are focused on the natural frequencies and frequency response function. Usually the femoral stem is tested although the acetabular cup fixation is important as well.

Biomechanical Effect of Ferrule on Incisors Restored with a Fiberglass Post and Lithium-Disilicate Ceramic Crown after Thermal Cycling and Fatigue Loading.

Purpose: To evaluate the biomechanics of endodontically treated incisors restored with a fiberglass post and a CAD/CAM lithium-disilicate ceramic crown with/without a ferrule after thermal and mechanical aging.

Materials And Methods: Twenty bovine incisors were divided into two groups (n = 10): 1. Fe, with a ferrule of 2 mm, and 2.

A prospective follow up of age related changes in the subchondral bone density of the talus of healthy Labrador Retrievers.

Background: During growth, the skeletal structures adapt to the increased loading conditions and mature to a fully-grown skeleton. Subchondral bone density reflects the effect of long-term joint loading and it is expected to change over time. The aim of this study was to describe the long-term changes in the density distribution of the subchondral bone of the talus of healthy Labrador Retrievers in a prospective study.

Determination of replicate composite bone material properties using modal analysis.

Replicate composite bones are used extensively for in vitro testing of new orthopedic devices. Contrary to tests with cadaveric bone material, which inherently exhibits large variability, they offer a standardized alternative with limited variability. Accurate knowledge of the composite's material properties is important when interpreting in vitro test results and when using them in FE models of biomechanical constructs.

Influence of Connection Types and Implant Number on the Biomechanical Behavior of Mandibular Full-Arch Rehabilitation.

Purpose: To evaluate the influence of different implant numbers and connection types on the biomechanical behavior of mandibular full-arch implant-supported rehabilitation.

Materials And Methods: Computed tomography-based finite element models comprising a totally edentulous mandible and 3.8 × 13-mmdiameter implants, abutments, abutment screws, bar retaining screw, and bar were constructed.

Bone Remodeling Around Implants with External Hexagon and Morse-Taper Connections: A Randomized, Controlled, Split-Mouth, Clinical Trial.

Objectives: To evaluate clinical, radiographic, microbiologic, and biomechanical parameters related to bone remodeling around implants with external hexagon (EH) and Morse-taper (MT) connections.

Materials And Methods: Twelve totally edentulous patients received four custom-made implants in the interforaminal region of the mandible. Two of those implants had the same macroscopic design, but different prosthetic connections.

Control of a hybrid robotic system for computer-assisted interventions in dynamic environments.

Purpose: Minimally invasive surgery is becoming the standard treatment of care for a variety of procedures. Surgeons need to display a high level of proficiency to overcome the challenges imposed by the minimal access. Especially when operating on a dynamic organ, it becomes very difficult to align instruments reliably and precisely.

Consequences of reaming with flat and convex reamers for bone volume and surface area of the glenoid; a basic science study.

Background: The effect of reaming on bone volume and surface area of the glenoid is not precisely known. We hypothesize that (1) convex reamers create a larger surface area than flat reamers, (2) flat reamers cause less bone loss than convex reamers, and (3) the amount of bone loss increases with the amount of version correction.

Methods: Reaming procedures with different types of reamers are performed on similar-sized uniconcave and biconcave glenoids created from Sawbones foam blocks.

Short fibre-reinforced composite for extensive direct restorations: a laboratory and computational assessment.

Objectives: The objective of the study was to evaluate the effectiveness of a short fibre-reinforced composite (FRC) applied in combination with a conventional filler composite (CFC) on the fatigue resistance, fracture strength, failure mode and stress distribution, for restorations of premolars under two loading angles.

Material And Methods: Thirty-two inferior premolars received extensive cavities with removal of the lingual cusp. Teeth were restored directly using 'FRC (EverX Posterior, GC) + CFC (G-aenial, GC)' or 'CFC only' and received two fatigue/fracture loadings at two different angles (0°/45°) (n = 8).

Creating a normative database of age-specific 3D geometrical data, bone density, and bone thickness of the developing skull: a pilot study.

Object: Finite element models (FEMs) of the head are used to study the biomechanics of traumatic brain injury and depend heavily on the use of accurate material properties and head geometry. Any FEM aimed at investigating traumatic head injury in children should therefore use age-specific dimensions of the head, as well as age-specific material properties of the different tissues. In this study, the authors built a database of age-corrected skull geometry, skull thickness, and bone density of the developing skull to aid in the development of an age-specific FEM of a child's head.

Insertion of a pressure sensing arrayminimally affects hindfoot bone kinematics.

Background: Understanding the development of ankle osteoarthritis (OA) is of high importance and interest; however its causality is poorly understood and several links to joint loading conditions have been made. One way of quantifying joint loading conditions is by measuring the intra-articular pressure distribution during gait simulations performed by in-vitro experimental set-ups. However the effect of inserting a pressure sensing array in the ankle joint could potentially disturb the proper kinematics and therefore the loading conditions.

Estimation of optimal pivot point for remote center of motion alignment in surgery.

Purpose: The determination of an optimal pivot point ([Formula: see text]) is important for instrument manipulation in minimally invasive surgery. Such knowledge is of particular importance for robotic-assisted surgery where robots need to rotate precisely around a specific point in space in order to minimize trauma to the body wall while maintaining position control. Remote center of motion (RCM) mechanisms are commonly used, where the RCM point is manually and visually aligned.

Load sharing and ligament strains in balanced, overstuffed and understuffed UKA. A validated finite element analysis.

The aim of this study was to quantify the effects of understuffing and overstuffing UKA on bone stresses, load distribution and ligament strains. For that purpose, a numerical knee model of a cadaveric knee was developed and was validated against experimental measurements on that same knee. Good agreement was found among the numerical and experimental results.

The biomechanical behaviour of the bridging vein-superior sagittal sinus complex with implications for the mechanopathology of acute subdural haematoma.

Background: Traumatic brain injury is expected to become the major cause of death and disability for children and young adults by the year 2020. One of the most frequent and most morbid pathologies resulted from a head trauma is acute subdural haematoma (ASDH). For nearly one third of the ASDH cases the etiopathology directly relates to a bridging vein (BV) rupture.

An evaluation of cardiorespiratory and movement features with respect to sleep-stage classification.

Polysomnography (PSG) is considered the gold standard to assess sleep accurately, but it can be expensive, time-consuming, and uncomfortable, specifically in long-term sleep studies. Actigraphy, on the other hand, is both cheap and userfriendly, but depending on the application lacks detail and accuracy. Our aim was to evaluate cardiorespiratory and movement signals in discriminating between wake, rapid-eye-movement (REM), light (N1N2), and deep (N3) sleep.

Alterated talar and navicular bone morphology is associated with pes planus deformity: a CT-scan study.

We compared bone and articular morphology of the talus and navicular in clinically diagnosed flatfeet and evaluated their potential contribution to talo-navicular joint instability. We used CT images to develop 3D models of talus and navicular bones of 10 clinically diagnosed flatfeet and 15 non-flatfeet. We quantified their global bone dimensions, inclination and dimensions of the articular surfaces and their curvatures.