Low back biomechanics during manual materials handling of beer kegs

2017 Fall.Includes bibliographical references.Biomechanical risk factors such as heavy loads and awkward trunk postures have been associated with occupational low back pain. Those same risk factors are commonly experienced among workers handling beer kegs. The present study used a 3-dimensional motion capture system as a tool to investigate the low back biomechanics during keg handling at a working brewery. Specifically, five workers transferred spent kegs from a pallet to a conveyor to be cleaned and filled with beer in the present study. Data was collected during the portion of the shift workers handled kegs. Low back angular displacements were assessed during keg handling at two heights. Kegs originated from a high or low position and were defined as a high or low lift. Kinematic data from the study was used to estimate compressive and shear forces at the lumbosacral joint from a 2-dimensional static biomechanical model. Repeated measures analyses were performed with each low back angular displacement variable as a function of lift condition. Differences in low back biomechanics between high and low lifts were identified. During low lifts, torso flexion was significantly greater than high lifts. The magnitudes of flexion achieved during low lifts significantly exceeded those of high lifts. Differences between left axial rotation where significant with larger magnitudes of rotation occurring during high lifts. A broader range of angular displacements was observed in high lifts. In both lifting conditions, estimated kinetics exceeded recommended action limits, potentially putting workers at an increased risk for developing low back pain. Work design (lift condition) influenced low back motion during keg handling. Data collection during operational hours was feasible due to the portability and small design of inertial measurement units. Results from the study can help improve workplace design in a craft brewery, reduce risk, and create safer work

Commercial and research-based wearable devices in spinal postural analysis: A systematic review

The widespread use of ubiquitous computing has led to people spending more time in front of screens, causing poor posture. The COVID-19 pandemic and the shift towards remote work have only worsened the situation, as many people are now working from home with inadequate ergonomics. Maintaining a healthy posture is crucial for both physical and mental health, and poor posture can result in spinal problems. Wearable systems have been developed to monitor posture and provide instant feedback. Their goal is to improve posture over time by using these devices. This article will review commercially available, and research-based wearable devices used to analyse posture. The potential of these devices in the healthcare industry, particularly in preventing, monitoring, and treating spinal and musculoskeletal conditions, will also be discussed. The findings indicate that current devices can accurately assess posture in clinical settings, but further research is needed to validate the long-term effectiveness of these technologies and to improve their practicality for commercial use

Design of Novel Experiments and Analyses for Head and Spine Trauma Biomechanics

Previous biomechanics research studies have used both whole-body and isolated postmortem human surrogate experiments to define human injury tolerances, advance safety in injury producing environments, and promulgate standards for design of injury mitigating systems. Recent developments in transportation and sports-related fields have led to an increasing need to determine tolerances for combined loading (multi-axis) scenarios. This dissertation demonstrates the efficacy of the novel experimental design and analysis to head and spine trauma in these modalities. The first topic was the design of a novel experiment to examine the effect oblique loading on the tension tolerance of the lumbar spine. To examine this injury tolerance, isolated lumbosacral spine experiments were used with a custom six degree-of-freedom spinal alignment device. The isolated experiment injury matched previous whole-body tests and failure kinetics were obtained. The second topic was the design of a novel experiment to measure the response of the head and neck to off axis moment loading at the occipital condyle joint. A dynamic rotational system applied angular displacement centered at the OC joint in an orientation that resulted in combined flexion-extension/lateral-bending/and axial rotation of the head. Region-specific anatomic kinetics were determined using load cells and a motion capture system. The third topic was the design of a novel experiment model to assess the accuracy of wearable sensors for concussion research. The goal of this topic was to design a new technique which placed a custom sensor near the head-center-of-gravity in whole-body and isolated head/head-neck PMHS. Tests were conducted to benchmark current wearable sensors in the sport and military environments. The measured head kinematics from the in-PMHS sensor serves as the gold standard for these tests. The fourth topic was design of a novel technique to compute three-dimensional time-varying global response kinematics of the head, spine, and pelvis in oblique frontal impacts. Collected data were combined to create three-dimensional temporal global kinematic corridors which are needed to validate current and future finite element models of the components/subsystems, human body models, and they can also be used for benchmarking different computational models

Studies on Spinal Fusion from Computational Modelling to ‘Smart’ Implants

Low back pain, the worldwide leading cause of disability, is commonly treated with lumbar interbody fusion surgery to address degeneration, instability, deformity, and trauma of the spine. Following fusion surgery, nearly 20% experience complications requiring reoperation while 1 in 3 do not experience a meaningful improvement in pain. Implant subsidence and pseudarthrosis in particular present a multifaceted challenge in the management of a patient’s painful symptoms. Given the diversity of fusion approaches, materials, and instrumentation, further inputs are required across the treatment spectrum to prevent and manage complications. This thesis comprises biomechanical studies on lumbar spinal fusion that provide new insights into spinal fusion surgery from preoperative planning to postoperative monitoring. A computational model, using the finite element method, is developed to quantify the biomechanical impact of temporal ossification on the spine, examining how the fusion mass stiffness affects loads on the implant and subsequent subsidence risk, while bony growth into the endplates affects load-distribution among the surrounding spinal structures. The computational modelling approach is extended to provide biomechanical inputs to surgical decisions regarding posterior fixation. Where a patient is not clinically pre-disposed to subsidence or pseudarthrosis, the results suggest unilateral fixation is a more economical choice than bilateral fixation to stabilise the joint. While finite element modelling can inform pre-surgical planning, effective postoperative monitoring currently remains a clinical challenge. Periodic radiological follow-up to assess bony fusion is subjective and unreliable. This thesis describes the development of a ‘smart’ interbody cage capable of taking direct measurements from the implant for monitoring fusion progression and complication risk. Biomechanical testing of the ‘smart’ implant demonstrated its ability to distinguish between graft and endplate stiffness states. The device is prepared for wireless actualisation by investigating sensor optimisation and telemetry. The results show that near-field communication is a feasible approach for wireless power and data transfer in this setting, notwithstanding further architectural optimisation required, while a combination of strain and pressure sensors will be more mechanically and clinically informative. Further work in computational modelling of the spine and ‘smart’ implants will enable personalised healthcare for low back pain, and the results presented in this thesis are a step in this direction

Sensores em fibra ótica para o estudo biomecânico do disco intervertebral

Doutoramento em Engenharia MecânicaO presente trabalho teve como objetivo principal estudar o comportamento mecânico do disco intervertebral recorrendo a sensores em fibra ótica. Na expetativa de efetuar o melhor enquadramento do tema foi efetuada uma revisão exaustiva das várias configurações de sensores em fibra ótica que têm vindo a ser utilizadas em aplicações biomédicas e biomecânicas, nomeadamente para medição de temperatura, deformação, força e pressão. Nesse âmbito, procurou-se destacar as potencialidades dos sensores em fibra ótica e apresentá-los como uma tecnologia alternativa ou até de substituição das tecnologias associadas a sensores convencionais. Tendo em vista a aplicação de sensores em fibra ótica no estudo do comportamento do disco intervertebral efetuou-se também uma revisão exaustiva da coluna vertebral e, particularmente, do conceito de unidade funcional. A par de uma descrição anatómica e funcional centrada no disco intervertebral, vértebras adjacentes e ligamentos espinais foram ainda destacadas as suas propriedades mecânicas e descritos os procedimentos mais usuais no estudo dessas propriedades. A componente experimental do presente trabalho descreve um conjunto de experiências efetuadas com unidades funcionais cadavéricas utilizando sensores convencionais e sensores em fibra ótica com vista à medição da deformação do disco intervertebral sob cargas compressivas uniaxiais. Inclui ainda a medição in vivo da pressão intradiscal num disco lombar de uma ovelha sob efeito de anestesia. Para esse efeito utilizou-se um sensor comercial em fibra ótica e desenvolveu-se a respetiva unidade de interrogação. Finalmente apresenta-se os resultados da investigação em curso que tem como objetivo propor e desenvolver protótipos de sensores em fibra ótica para aplicações biomédicas e biomecânicas. Nesse sentido, são apresentadas duas soluções de sensores interferométricos para medição da pressão em fluídos corporais.The present work aimed to study the mechanical behavior of the intervertebral disc using fiber optic sensors. To address the theme an exhaustive review of the various configurations of fiber optic sensors that have been used in biomechanical and biomedical applications, in particular for measuring temperature, strain, force and pressure, was conducted. In this context, an effort was made to highlight the advantages of fiber optic sensors and present them as an alternative or even a substitution technology to conventional sensors. In view of the application of fiber optic sensors to study intervertebral disc behavior an exhaustive review of the spine and, particularly, of the spinal motion segment was made. Along with an anatomical and functional description of the intervertebral disc, the adjacent vertebrae and spinal ligaments, their mechanical properties were also highlighted as well as the most common procedures and guidelines followed in the study of these properties. The experimental section of the present work describes a set of tests performed with cadaveric spinal motion segments using conventional and fiber optic sensors to assess strain of the intervertebral disc under uniaxial compressive loads. This section also includes an experience reporting in vivo pressures measured in the lumbar disc of a sheep under general anesthesia. In this case, a commercial fiber optic sensor and a purpose-built interrogation unit were used. Finally, the results of ongoing research aiming to develop fiber optic sensors prototypes for biomedical and biomechanical applications are presented. Thus, the proof of concept of two possible interferometric configurations intended for pressure measurement in body fluids was presented

Spinal Cord Injury and Transcutaneous Spinal Cord Stimulation

Recent research of epidural and transcutaneous electrical spinal cord stimulation has demonstrated unprecedented improvements in motor function thought to be irreversibly lost due to chronic, severe spinal cord injury. Studies in parallel assess these methods for spasticity management as an alternative to medications that are often accompanied by deleterious side effects. As a noninvasive intervention, transcutaneous spinal cord stimulation holds the great potential to find its way into wide clinical application. Its firm establishment and lasting acceptance as clinical practice in spinal cord injury will not only hinge on the demonstration of safety and efficacy, but also on the delineation of a conceptual framework of the underlying physiological mechanisms. This will also require advancing our understanding of immediate and temporary effects of transcutaneous spinal cord on neuronal circuits in the intact and injured spinal cord. The purpose of this collection of papers is to bring together peers in the field to share—and eventually fuse—their pertinent research into current neurorehabilitation practice by providing a clinical perspective and novel insights into the underlying mechanisms

Efficacy of a Novel Thoracopelvic Orthosis in Reducing Lumbar Spine Loading and Muscle Fatigue in Flexion: A Study with Weighted Garments.

The purpose of this thesis was to design and test a novel electromechanical thoracopelvic orthosis called the Exoskeletal Spinal Support, or ESS. We tested the overall hypothesis that the activity of the postural muscles of the lower back in erect and flexed postures, while wearing and not wearing a weighted garment, can be reduced by the ESS. Two experiments informed the design of the ESS. The first experiment was a repeated-measures study of the effect of a weighted garment (a lead vest) on shoulder and lower back muscle activity of 19 young healthy adults. The results showed that use of the lead vest did not significantly increase muscle activity in any of the three muscle groups studied. The second experiment was a repeated-measures study of factors contributing to the normal contact stress developed at the interface between a partial thoracic orthosis and the skin of 20 healthy young men. The ESS was designed and programmed so that its microcontroller monitored the interface contact stress and commanded its four linear actuators to adjust the orthosis configuration so as to maintain a near-constant trunk extensor moment over a range of trunk flexion. The final experiment was a preliminary validation study of the ESS on a single subject in a variety of loading conditions and flexed postures, with lumbar muscle activity as the primary outcome. The results suggest that at 5° forward flexion, the ESS reduced normalized erector spinae muscle activity by up to 11%. However, when the lead vest was worn over the ESS, muscle activity increased, perhaps due to a change in spine posture or an artifact. Nonetheless we conclude that the ESS has promise as the first “active” orthosis. Its mechanical interactions with the trunk can be programmed via software alone. These interactions include the use of the constant corrective moment used here, but also include the ability to change the damping behavior and program any linear or curvilinear relationship between applied moment and thorax inclination in the sagittal or coronal planes. This technology allows for the possibility of telemanaging orthotic treatment in the future.Ph.D.Mechanical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/91450/1/danijohn_1.pd