Mark Driscoll

McGill University | McGill · Department of Mechanical Engineering

Cadaveric studies are considered as the gold standard for spinal biomechanics research and more recently there has been a noticeable increase in finite element modeling applications in the field. But both these methods are not without their limitations. The current research proposes validated alternative methods to these traditional approaches that...

Spine biomechanical testing methods in the past few decades have not evolved beyond employing either cadaveric studies or finite element modeling techniques. However, both these approaches may have inherent cost and time limitations. Cadaveric studies are the present gold standard for spinal implant design and regulatory approval, but they introduc...

Objective: This study investigates the potential for stress shielding within musculoskeletal soft tissues through analysis of stress distributions between lumbar fascial and muscle tissues via mechanical testing. Methods: Using a custom apparatus, 51 posterior thoracolumbar fascia (TLF) samples and 18 erector spinae (ES) cadaveric samples underw...

Mixed-reality surgical simulators are seen more objective than conventional training. The simulators’ utility in training must be established through validation studies. Establish face-, content-, and construct-validity of a novel mixed-reality surgical simulator developed by McGill University, CAE-Healthcare, and DePuy Synthes. This study, approve...

This study aims to understand the impact forces that surgeons apply to the human spine during a posterior spinal fusion procedure towards the development of a novel spine surgical simulator for training medical residents. The foci of this study are impact forces during graft placement and spinal interbody cage insertion. This study examined the lum...

In this article, a robust adaptive impedance control based on the modified function approximation technique, and augmented with a novel integral nonsingular terminal sliding mode control, is proposed for a surgical haptic system. The haptic device is maneuvered by surgeons, whereby the mode of action, motion path, and haptic dynamics are rendered a...

BACKGROUND CONTEXT: The current surgical practices are undergoing the evolutionary adoption of mixed reality-based technologies. Augmented reality (AR) comes into the field as a possible way of augmentation of the real anatomical structure during surgery without any attention drift of the surgeon. Operative error is a major concern during complex s...

BACKGROUND: Analogue biomechanical models are powerful tools to further the understanding of human spine. As opposed to cadaveric studies and finite element models these models are time and cost effective. An effort is made to develop an analogue biomechanical model of human thoracolumbar fascia (TLF) and characterize its mechanical properties. MET...

BACKGROUND CONTEXT Low back pain (LBP) is a public health crisis with nearly 85% of cases considered idiopathic. With the emergence of research analyzing the role of the thoracolumbar fascia (TLF) in spinal biomechanics, it is possible that the fascia may play a role in the progression of LBP. Previous studies have demonstrated changes to the TLF t...

BACKGROUND CONTEXT The unstable nature of the spine motivates the use of optimization and electromyography (EMG) methods to estimate its individual muscles force activation. Conventionally, muscles are modelled as force vectors negating enclosed constituents such as intramuscular pressure (IMP), a parameter that has been previously shown to influen...

BACKGROUND CONTEXT The spine is an inherently unstable structure due to the numerous degrees of freedom it possesses. Yet, its static spinal stability is believed to be maintained by the actions of muscle activations combined with their intramuscular pressure (IMP), intra-abdominal pressure (IAP) generated by the abdominal muscles, and the passive...

Simulation in surgical training is a growing field and this study aims to understand the force and torque experienced during lumbar spine surgery to design simulator haptic feedback. It was hypothesized that force and torque would differ among lumbar spine levels and the amount of tissue removed by ≥ 7%, which would be detectable to a user. Force a...

Many cadaveric studies and Finite Element (FE) models are used to explore the biomechanics of the lumbar spine and spinal stability in the past and yet the pathomechanisms of many low back related diseases are not fully understood. Cadaveric studies often involve assumptions pertaining to patient’s previous medical history [1]. FE studies on the ot...

Background Abdominal compliance is the “measure of ease of abdominal expansion” and determines whether a patient can withstand high intra-abdominal pressures. Thus, high compliance indicates that the abdomen can expand relatively freely, while low compliance restricts abdominal expansion. The global objective of the present work is to evaluate the...

Optimization models are often devised to assess spinal stability via estimating individual muscle forces. However, neglecting muscles' fluidic behavior remains an approximation due to the role of muscle pressure in force transmission. The purpose of this study was to leverage a validated Finite Element (FE) model of the spine, inclusive of Intra-Mu...

Intra-abdominal hypertension has been recorded in between 20 and 50% of intensive care unit patients, with rates increasing in ventilated patients. This increased intra-abdominal pressure (IAP) can reduce blood flow to vital organs, perpetuating further pressure build-up as organs become unable to drain excess fluids. Measurement of IAP for the dia...

Robotic devices are commonly used in surgical simulators to provide tactile, or haptic, feedback. They can provide customized feedback that can be rapidly modified with minimal hardware changes in comparison to non-robotic systems. This work describes the design, development, and evaluation of one such tool: a novel uniaxial torque haptic device fo...

The employment of force-feedback haptic devices in surgical simulators has faced several challenges given the high computational cost. In cases of minimally invasive spinal fusion surgeries, the internal tissue deformation cannot be visually perceived. This presents an opportunity to render haptic forces independent of visual simulation. Hence, thi...

Most surgical simulators leverage virtual or bench models to simulate reality. This study proposes and validates a method for workspace configuration of a surgical simulator which utilizes a haptic device for interaction with a virtual model and a bench model to provide additional tactile feedback based on planned surgical manoeuvers. Numerical ana...

Purpose: The inclusion of muscle pressure in muscle models may have important implications in biomechanics. This notion builds from the known correlation between muscle contractile force and internal pressure. However, this relation is often omitted in numerical models leveraged to study biomechanics. Thus, the purpose of this study was to develop...

Low back pain (LBP) is a common affliction, yet the pathomechanism of LBP continues to allude researchers. With the growing evidence from research surrounding the biomechanical importance of fascia, this tissue may play a role in the progression of LBP. Morphological and material property changes to lumbar muscles whose primary role is to stabilize...

Low back pain is a public health crisis with nearly 85% of cases being unattributed to a specific cause. With the emergence of research concerning fascia’s contributions to spinal biomechanics, fascia may contribute to the progression of low back pain. For example, the thoracolumbar fascia (TLF) has demonstrated increased morphological thickness in...

Study design: Numerical in-silico human spine stability finite element analysis. Objective: The purpose of this study was to investigate the contribution of major torso tissues toward static spine stability, mainly the thoracolumbar fascia (TLF), abdominal wall with its intra-abdominal pressure (IAP), and spinal muscles inclusive of their intram...

Modeling the mechanical behavior of soft tissue probe insertion remains a challenging endeavor due to involved interdependent phenomena comprising tissue nonlinear deformation, contact between the probe and the tissue, crack propagation, and viscoelastic effects. To that matter, cohesive elements allow simulating crack formation and propagation, wh...

Spinal instability remains a complex phenomenon to study while the cause of low back pain continues to challenge researchers. The role of fascia in biomechanics adds to the complexity of spine biomechanics but offers a new window from which to investigate our spines. Specifically, the thoracolumbar fascia may have an important role in spine biomech...

Background Virtual reality surgical simulators are a safe and efficient technology for the assessment and training of surgical skills. Simulators allow trainees to improve specific surgical techniques in risk-free environments. Recently, machine learning has been coupled to simulators to classify performance. However, most studies fail to extract m...

Despite the prevalence of low back pain (LBP) in society, the pathomechanism of LBP continues to elude researchers. LBP patients have demonstrated morphological and material property changes to their lumbar soft tissues, potentially leading to irregular load sharing within the lumbar spine. This study aims to analyze potential stress shielding cons...

Recently, haptics manipulators have grown to become the most significant robotics technology development, being widely used successfully in surgical training simulators. This allows human operators to interact with a virtual reality (VR) environment and enhance the sensory experience. However, this technology remains to be fully exploited and its...

Cupping therapy is a growing treatment option for myofascial pain for its suggested ability to elongate and increase elasticity of biological tissue. However, the effect of suction on deeper tissues' elasticity has not been well documented. As such, elasticity was derived using a novel device that employs a flash cupping technique to move deeper fa...

Introduction The pathomechanism of low back pain (LBP) remains unknown. Unilateral LBP patients have demonstrated ipsilateral morphological and material property changes within the lumbar soft tissues, potentially leading to asymmetric tissue loading. Through the comparison of healthy and unilateral LBP validated finite element models (FEMs), this...

Numerous spine Finite Element (FE) models have been developed to assess spinal tolerances, spinal loadings and low back pain-related issues. However, justified simplifications, in terms of tissue decomposition and inclusion, for such a complex system may overlook crucial information. Thus, the purpose of this research was to develop and validate a...

The following paper presents the design, implementation, and validation of a new adaptive control system based on the Modified Function Approximation Technique (MFAT) augmented with backstepping control for a haptic robot with unknown dynamic and actuator parameters, employed in a spinal surgical simulator. The combination of backstepping control a...

The human body is comprised of a series of pressurized vessels, including muscles, organs, abdominal and thoracic compartments. One such vessel is the intra-abdominal volume, or volume contained by the peritoneum, pressurized by intra-abdominal pressure (IAP). Existing clinically-accepted IAP measurement techniques are invasive and not inter-rater...

This poster is a comparison of energy loss in the hysteresis torque curve during a lumbar discectomy. It can be viewed at: https://www.epostervirtual2020.eurospine.org/cm_data/eposter/P4.PDF

A new adaptive impedance, augmented with backstepping control, time-delay estimation, and a disturbance observer, was designed to perform passive-assistive rehabilitation motion. This was done using a rehabilitation robot whereby humans’ musculoskeletal conditions were considered. This control scheme aimed to mimic the movement behavior of the user...

This paper presents the design, and validation of a new adaptive control system based on quasi-time delay estimation (QTDE) augmented with new integral second-order terminal sliding mode control (ISOTSMC) for a manipulator robot with unknown dynamic uncertainty and disturbances. Contrary to the conventional TDE, the proposed Q-TDE becomes sufficien...

Introduction: Virtual Reality haptic-based surgical simulators for training purposes have been recently receiving increased traction within the medical field. However, its future adoption is contingent on the accuracy and reliability of the haptic feedback. Goal: This study describes and analyzes the implementation of a set of haptic-tailored ex...

Thoracolumbar fascia involvement is often neglected when studying the biomechanics of the spine. The purpose of this study was to develop, validate, and explore the use of a novel finite element model of the spine, inclusive of the Thoracolumbar Fascia, Paraspinal Muscular Compartment (PMC) and the Intra-Abdominal Pressure (IAP) based on published...

A robotic spine model was developed complete with analog bones, pneumatic muscles, and artificial cavities. The model was automated through a control system including automatic valves, a position tracking system, and pressure sensors. This robotic spine model successfully underwent preliminary validation, therefore establishing its relevance as a f...

With the correlation of low back pain (LBP) and augmentation of the morphological and mechanical properties of the lumbar soft tissues, cyclical stress shielding may be introduced into the musculoskeletal system of LBP patients. As such, this study aimed to investigate the potential for a load allocation bias within the musculoskeletal system leadi...

Reflective writing or exam wrappers appear to be a valuable exercise that may benefit students. This notion was evaluated in parallel within five engineering classrooms of different size and subject matter. The improvement or quantifiable impact of the reflective writing exercise differed from class to class. Despite this, overall results suggest t...

Acquiring metacognitive skills, i.e. selfassessment of study behaviors through exam-wrappers, would potentially have concrete positive effects on students learning. The purpose of this study was to assess the link between students’ performance and study behaviors, to analyze their metacognitive skills. Exam-wrappers consisted of 4 fundamental quest...

This work addresses the current lack of robotic haptic torque devices in virtual reality and augmented reality (VR/AR) surgical training platforms. A torque handle that can augment existing haptic force devices has been designed to produce up to 3N-m of continuous torque at 38rpm. This device will be used to expand the scope and perceived realism o...

The minimum belt strain required to support intra-abdominal pressures (IAP) was evaluated for ostomy patients. Recommendations were detailed for males and females, as well as three distinct activity levels.

Acquiring metacognitive skills, i.e. self-assessment of study behaviors through exam-wrappers, would potentially have concrete positive effects on students learning. The purpose of this study was to assess the link between students' performance and study behaviors, to analyze their metacognitive skills. Exam-wrappers consisted of 4 fundamental ques...

Low back pain affects 4/5 individuals at some point in their lifetime. However, the spine is a musculoskeletal system that is not fully understood. To advance musculoskeletal biomechanical research and to study spinal stability, an robotic spine model was designed complete with analog bones, pneumatic muscles, and artificial cavities. A control sys...

Study Design: Biomechanical numerical simulation analysis of implant design and density in adolescent idiopathic scoliosis posterior instrumentation. Objectives: To evaluate the combined effect of pedicle screw design and density on deformity correction and construct load-sharing capacity. Summary of Background Data: Screw density is an area of p...

Although the fascia has been studied for a long time, science has only recently begun to pay more attention to the exploration of this network in our bodies. The essential role the fascia plays for body perception and the mobility of body structures is now being explored. After a brief look at the fascia as a specialized connective tissue, we intro...

This was a poster presented at the Canadian Society for Biomechanics (CSB 2018) about the development of a novel finite element modelling procedure for skeletal muscles using the notion of intra-muscular pressure.

This study evaluated the correlation between intra-abdominal pressure and spinal stability through the use of a robotic spine model. The study aimed to determine the required intramuscular pressure to maintain stability of the robotic spine model when subjected to a compressive load and with varying intra-abdominal pressures.

Obwohl schon lange mit Faszien gearbeitet wird, schenkt die Wissenschaft erst seit Kurzem der Erforschung dieses Netzwerks in unserem Körper zunehmende Beachtung. So wird die wesentliche Rolle erforscht, die Faszien für die Körperwahrnehmung und die Beweglichkeit der Körperstrukturen spielen. Nachdem wir einen kurzen Blick auf die Faszie als spezia...

Invited Editorial

Study Design: In vivo porcine model utilized to evaluate the influence of an intravertebral fusionless growth modulating device (hemi-staple) on intervertebral disks and growth plates. Objective: To evaluate the radiographic and histologic changes in disks and growth plates with the purpose of measuring influence of the explored hemi-staple. Summar...

Hip subluxation in children with Cerebral Palsy (CP) has an incidence of 10-30 %, and children with severe CP having the highest incidence. The condition deteriorates if left untreated. Surgery is the most common method used in managing hip subluxation because standard conservative therapies do not improve it. Surgery may have to be repeated and co...

Ph.D. Thesis pertaining to the design, development and evaluation of a novel fusionless treatment implant for spinal deformities

Study design: A biomechanical spine model was used to evaluate the impact of screw design on screw-vertebra interface loading during simulated surgical corrections of adult scoliosis. Objectives: To evaluate differences in screw-vertebra interface forces during adult scoliosis correction between favored angle (FA) screws with extension tabs and...

A method for installing a surgical device on a spine for applying corrective forces thereon comprises installing at least one anchor on a first vertebra and at least another anchor on a second vertebra. At least one connector is installed on at least one of the first and the second vertebrae. A flexible tether is fixed to one of the anchors. The fl...

Background Mobile smartphones are equipped with inclinometers enabling them to acquire angular clinical measures. The Scolioscreen has been developed in conjunction with a smartphone APP to enable the measure of the angle of trunk inclination (ATI) thus offering a convenient and reliable means to measure and screen for spinal deformities. The objec...

Study design:: In vivo porcine model utilized to evaluate the influence of an intravertebral fusionless growth modulating device (hemi-staple) on intervertebral discs and growth plates. Objective:: Evaluate radiographic and histological changes in discs and growth plates with the purpose of measuring influence of the explored hemi-staple. Summa...

Study DesignBiomechanical finite element models simulated deformity correction using pedicle screw instrumentation and measured forces at the screw–vertebra interface.Objectives Compare 2 different screw designs with respect to reaction forces at screw–vertebra interfaces during scoliosis correction maneuvers.Summary of Background DataPedicle screw...