Kathleen Denis

KU Leuven | ku leuven · Department of Mechanical Engineering

The study aim was to compare the geometric accuracy of three-dimensional (3D) surface model reconstructions between five Cone Beam Computed Tomography (CBCT) scanners and one Multi-Slice CT (MSCT) system. A dry human mandible was scanned with five CBCT systems (NewTom 3G, Accuitomo 3D, i-CAT, Galileos, Scanora 3D) and one MSCT scanner (Somatom Sens...

Background: Accurate pre-clinical evaluation of the initial stability of new cementless hip stems using in vitro micromotion measurements is an important step in the design process to assess the new stem's potential. Several measuring systems, linear variable displacement transducer-based and other, require assuming bone or implant to be rigid to...

The initial stability of cementless total hip arthroplasty (THA) implants is obtained by an interference fit that allows osseointegration for a long term secondary stability of the implant. Yet, finding the insertion endpoint that corresponds to an appropriate initial stability is currently often based on a number of subjective experiences of the o...

Replicate bones are widely used as an alternative for cadaveric bones for in vitro testing. These composite bone models are more easily available and show low inter-specimen variability compared to cadaveric bone models. The combination of in vitro testing with in silico models can provide further insights in the evaluation of the mechanical behavi...

The total number of total hip arthroplasties is increasing every year, and approximately 10% of these surgeries are revisions. New implant design and surgical techniques are evolving quickly and demand accurate preclinical evaluation. The initial stability of cementless implants is one of the main concerns of these preclinical evaluations. A broad...

Bone conduction implants enable patients to hear via vibrations transmitted to the skull. The main constraint of current bone conduction implants is their maximum output force level. Stimulating closer to the cochlea is hypothesized to increase efficiency and improve force transfer, addressing this limitation. This study evaluated stimulation at fo...

Skeletal gyroid structures possess promising applications in biomedical implants, owing to their smooth and continuously curved surfaces, open porosity, and customisable mechanical properties. This study simulated the geometric properties of Ti6Al4V skeletal gyroid structures, with relative densities ranging from 1.83% to 98.17%. The deformation be...

Ti6Al4V Voronoi structures are unique lattice structures with high potential in biomedical applications, owing to their tuneable mechanical properties and superior biocompatibility. Unlike unit cell-based lattice structures, Voronoi structures have struts that are oriented in any direction relative to the build direction, which impedes process opti...

The study evaluates the accuracy of predicting intracochlear pressure during bone conduction stimulation using promontory velocity and ear canal pressure, as less invasive alternatives to intracochlear pressure. Stimulating with a percutaneous bone conduction device implanted in six human cadaveric ears, measurements were taken across various inten...

In the research field of robotic spine surgery, there is a big upcoming momentum for surgeon-like autonomous behaviour and surgical accuracy in robotics which goes beyond the standard engineering notions such as geometric precision. The objective of this review is to present an overview of the state of the art in non-visual, non-radiative spine sen...

Lumped element models facilitate investigating the fundamental mechanisms of human ear sound conduction. This systematic review aims to guide researchers to the optimal model for the investigated parameters. For this purpose, the literature was reviewed up to 12 July 2023, according to the PRISMA guidelines. Seven models are included via database s...

Pedicle drilling is a complex and critical spinal surgery task. Detecting breach or penetration of the surgical tool to the cortical wall during pilot-hole drilling is essential to avoid damage to vital anatomical structures adjacent to the pedicle, such as the spinal cord, blood vessels, and nerves. Currently, the guidance of pedicle drilling is d...

(1) Background: Many professional and recreational cyclists experience that neck extension in time trial position negatively impacts either speed, comfort, or power production—especially at high cycling speeds or for long distances. We conducted a feasibility study with one subject to assess whether redirecting the sight of a cyclist while in time...

The mechanical properties of an electrospun membrane by adding a lamination process to its production are improved. The aim is to improve the maximum force and the deformation energy obtained during a uniaxial tensile test. The investigated parameters for the lamination process are the towing velocity, number of layers, lamination time and temperat...

Accurate tissue differentiation during orthopedic and neurological surgeries is critical, given that such surgeries involve operations on or in the vicinity of vital neurovascular structures and erroneous surgical maneuvers can lead to surgical complications. By now, the number of emerging technologies tackling the problem of intraoperative tissue...

This paper presents a review of surgical simulators, developed to enhance the learning process of surgical procedures, that involves bones, ranging from musculoskeletal system (orthopedics) and the skull (ENT and neurosurgeries). The paper highlights the specific challenges in terms of the extended reality representation of surgical training along...

In cementless Total Hip Arthroplasty (THA), achieving high primary implant fixation is crucial for the long-term survivorship of the femoral stem. While orthopedic surgeons traditionally assess fixation based on their subjective judgement, novel vibration-analysis fixation-monitoring techniques show promising potential in providing the surgeon with...

This study presents a new design for the jaws used in the uniaxial tensile testing of PA6 electrospun membranes. The aims of the new design are both to accelerate the clamping process and additionally reduce the paper waste created by paper frames. In order to validate the efficiency of the new design, the newly developed jaws were compared both wi...

Aseptic loosening due to periprosthetic osteolysis has been accepted as one of the leading causes of revision procedures in patients with previous joint arthroplasty. Recently, several strategies for suppression of osteolysis were proposed, mostly based on biological treatment such as mitigation of chronic inflammatory reactions. However, these bio...

Objective: The level of primary implant fixation in cementless total hip arthroplasty is a key factor for the longevity of the implant. Vibration-based methods show promise for providing quantitative information to help surgeons monitor implant fixation intraoperatively. A thorough understanding of what is driving these changes in vibrational beha...

Electrospun membranes are being found in many applications and one of them is filtration. Their performance shows a high filtration efficiency that reaches almost 100% for particles below 2.5 μm. The main focus of this study was to firstly experimentally measure the filtration characteristics of electrospun membrane, i.e. pressure drop as a functio...

In this work, a new model for filtration is developed using statistical capturing mechanisms. The model can be used in the macroscale simulation of filtration processes and can replace the current semi-empirical models based on the Single Fibre Efficiency. To validate the new model, firstly, simulation of the filtration process itself is implemente...

The emergence of steerable flexible instruments has widened the uptake of minimally invasive surgical techniques. In sinus surgery, such flexible instruments could enable the access to difficult-to-reach anatomical areas. However, design-oriented metrics, essential for the development of steerable flexible instruments for maxillary sinus surgery, a...

The instruments currently used by surgeons for in utero treatment of the twin-to-twin transfusion syndrome (TTTS) are rigid or semi-rigid. Their poor dexterity makes this surgical intervention risky and the surgeon’s work very complex. This paper proposes the design, assembly and quantitative evaluation of an add-on system intended to be placed on...

Purpose: Smaller incisions and reduced surgical trauma made minimally invasive surgery (MIS) grow in popularity even though long training is required to master the instrument manipulation constraints. While numerous training systems have been developed in the past, very few of them tackled fetal surgery and more specifically the treatment of twin-...

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. The results of implant stability assessment are inconsistent and seem to...

Surgical interventions are increasingly executed minimal invasively. Surgeons insert instruments through tiny incisions in the body and pivot slender instruments to treat organs or tissue below the surface. While a blessing for patients, surgeons need to pay extra attention to overcome the fulcrum effect, reduced haptic feedback and deal with lost...

The preoperative diagnosis of loosening of cemented tibial knee implants is challenging. This feasibility study explored the basic potential of a vibration-based method as an alternative diagnostic technique to assess the fixation state of a cemented tibia implant and establish the method's sensitivity limits. A combined in vitro and in silico appr...

In cementless total hip arthroplasty (THA), the initial stability is obtained by press-fitting the implant in the bone to allow osseointegration for a long term secondary stability. However, finding the insertion endpoint that corresponds to a proper initial stability is currently based on the tactile and auditory experiences of the orthopedic surg...

In cases of severe rheumatoid arthritis or osteoarthritis, the hip joint is substituted by an artificial joint composed of a femoral stem fitted with a spherical head that can rotate inside a cup inserted in the acetabulum. This procedure is called total hip replacement (THR) and is one of the most frequently performed orthopaedic surgeries. For a...

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...

During cementless total hip arthroplasty (THA) the implant is press-fitted into the bone, this initial fixation is crucial to allow bone ingrowth for a long term stability of the implant. The point of optimal initial fixation is currently found by the tactile and auditory experience of the orthopedic surgeon, which can be challenging. A real-time a...

Background: Glenoid dissociation is a rare postoperative complication in reverse shoulder arthroplasty that has severe consequences for the patient and requires revision in most cases. A mechanically compromised Morse taper is hypothesized to be the main cause of this complication, with bony impingements and soft tissue interpositioning being cite...

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: Reamin...

Sawbones fourth-generation composite bones are used extensively for in vitro testing of boneimplant constructs. These composite bones have been developed in order to closely mimic the mechanical properties of human bone. The in vitro tests are often complemented with FE models in order to better understand the test results. It is crucially importan...

A large number of cementless total hip arthroplasties (THA) are performed every year, during which the hip joint is replaced by an artificial implant. The primary fixation of the femoral component of a cementless THA is obtained by press-fitting the implant in the femur. At present, this primary fixation is determined by the subjective auditive and...

Micromotions are cyclic implant-bone relative displacements induced by physiological loads. This phenomenon may trigger the loosening process or at least contribute to it if the relative micromovements exceed 150 μm [Viceconti 2000]. Therefore, measuring the micromotion is a method to assess the stability of the implant-bone structure. The existing...

A large number of total knee arthroplasties are performed every year, during which the knee joint is replaced by an artificial implant. Although literature shows high survival rates, the number of revisions is high, due to the large number of primary TKA’s: approximately 5 to 10% of the prostheses need to be replaced within 10 to 15 years. Loosenin...

A large number of total knee arthroplasties are performed every year, during which the knee joint is replaced by an artificial implant. Although literature shows high survival rates, the number of revisions is high, due to the large number of primary TKR’s: approximately 5 to 10% of the prostheses need to be replaced within 10 to 15 years. Loosenin...

Group T University College (Leuven, Belgium) organizes academic engineering programs with following majors: electromechanical engineering, electronics engineering, chemical engineering and biochemical engineering. The main mission of the University College is education, but also applied research, internationalization and cooperation with (especiall...

To evaluate image quality by examining segmentation accuracy and assess radiation dose for cone beam CT (CBCT) scanners. A skull phantom, scanned by a laser scanner, and a contrast phantom were used to evaluate segmentation accuracy. The contrast phantom consisted of a polymethyl methacrylate (PMMA) cylinder with cylindrical inserts of air, bone an...

We present a protocol for the evaluation of the geometric accuracy of bone segmentation algorithms in multi-slice and conebeam computed tomography (CT) Three important issues are resolved in this protocol: construction of a skull phantom with an accurate geometrical description serving as gold standard; registration between this geometric model and...

Bone cutting in total joint reconstructions requires a high accuracy to obtain a well-functioning and long-lasting prosthesis. Hence robot assistance can be useful to increase the precision of the surgical actions. A drawback of current robot systems is that they autonomously machine the bone, in that way ignoring the surgeon's experience and intro...

This paper presents a novel measuring system for the detection of moving skeletal structures. The system uses white light raster line triangulation in combination with biomechanical modeling techniques. White light raster line triangulation visualizes surfaces (e.g. the back surface) in an accurate and repeatable way, without detrimental effects, a...

An abstract is not available.

The authors have implemented registration procedures by means of an intramedullary rod and by means of surface matching in their robot-assisted procedure for milling the tibia in TKA. Registration by means of an intramedullary rod is a simple and fast procedure that does not need CT-images. The accuracy is better than 2° in the frontal plane. In ca...

A robot-assisted procedure using force control for machining the tibia in total knee arthroplasty (TKA) has been developed. A registration method based on surface matching has been implemented. This method uses an algorithm based on the iterative closest point algorithm. The implemented algorithm matches a set of points, intraoperatively digitized...

A robot-assisted procedure using force control for machining the tibia in total knee arthroplasty (TKA) has been developed. A registration method based on surface matching has been implemented. This method uses an algorithm based on the iterative closest point algorithm. The implemented algorithm matches a set of points, intraoperatively digitized...

Technology is being integrated more and more in surgery to increase the quality of patient treatment. The surgeon’s manual skills are complemented by navigation systems, surgical robots or individualised mechanical guides. Navigation systems track the motion of surgical instruments relative to the patient’s organs. Surgical robots have been develop...

In a robot-assisted procedure for preparing the tibia in total knee arthroplasty, developed in the authors' laboratory, an intramedullary rod is used to register the tibia. In 18 formalin-fixed tibias, the difference in orientation was calculated between the intramedullary rod and several longitudinal tibial axes used in clinical practice. This was...

The authors have developed a robot-assisted procedure to prepare the tibial surface in total knee arthroplasty (TKA). Using hybrid force/velocity control, the surgeon machines the bone by means of an end mill attached to the robot-arm. The milling forces can give information on the local bone quality intra-operatively. This paper describes experime...

Total knee arthroplasty requires accurate preparation of the bone surfaces to maximize bone implant contact area in cementless surgery and to obtain proper joint kinematics and ligament balancing. Robots can make the cuts with the necessary high precision. The purpose of this article is threefold: to propose an alternative method for intraoperative...