Characterizing soft tissue stress for ameliorating injury in performing process

Abstract

To obtain material scientific properties of soft tissue for use in a damage model for ameliorating injuries in an individual performing a process.SOLUTION: A method can include obtaining physical parameters characterizing the soft tissue of the individual under each of multiple loading conditions, fitting a soft tissue damage model based on the parameters, and ameliorating injuries in performing the process by implementing guidelines based on the soft tissue damage model.SELECTED DRAWING: None

Description

Technical Field

[0001]

[0001] The subject matter described herein generally relates to ergonomics and industrial hygiene. More specifically, the subject matter disclosed herein relates to the acquisition of physical parameters used to create guidelines for preventing or reducing repetitive stress injuries to soft tissue.

Background Art

[0002]

[0002] Injuries due to overuse, particularly of the shoulder (including the supraspinatus tendon), are among the most serious of ergonomic injuries. Thus, in order to address the tasks or task repetitions that cause the injury, it is necessary to understand the dynamics of the workplace or other activities that contribute to and can cause stress on tendons, for example.

[0003]

[0003] Existing ergonomic analyses and recommendations typically rely on theoretical constructs based on an overly simplified characterization of the shoulder joint complex. These may rely on psychophysical estimates of acceptable levels of motion or the generalization of forces to the shoulder joint from a single moment load at a point. Existing approaches provide only limited estimates of risk and have limited practical use.

[0004]

[0004] Furthermore, medical, therapeutic, and pharmacological research is dedicated to (or focuses on) individuals after an injury has occurred, namely surgical interventions, physiotherapy regimens, and treatments to accelerate recovery. Injury detection is focused not on screening for risk before an injury occurs, but after a patient has self-reported an injury. Conventional ergonomic practices attempt to prevent injuries, but this is done, or has been done, only at a macro level using epidemiological methods. That is, based on estimated work exposure, estimates are made of when a person will self-report an injury based on the level of discomfort or pain, and guidelines are made to fall below that threshold. And most injuries are defined by general body areas such as the shoulder, knee, or entire back, rather than by individual components. [Overview of the Initiative]

[0005]

[0005] This disclosure includes examples provided in the following clauses.

[0006]

[0006] Clause 1. A method for obtaining material science properties of soft tissue for use in an injury model to improve injuries of an individual performing a process, comprising obtaining physical parameters characterizing the individual's soft tissue under each of a plurality of load conditions, fitting a soft tissue injury model based on the parameters, and implementing guidelines based on the soft tissue injury model to improve injuries when performing the process.

[0007]

[0007] Clause 2. The method according to Clause 1, wherein obtaining physical parameters includes measuring at least one parameter of soft tissue using an ultrasound device.

[0008]

[0008] Clause 3. The method according to either Clause 1 or 2, wherein the ultrasonic device includes a shear wave ultrasonic device and the parameter includes the shear modulus.

[0009]

[0009] Clause 4. The method according to any one of Clauses 1, 2, or 3, wherein the ultrasonic device includes a longitudinal ultrasonic device, and the parameters include at least one of Young's modulus or the cross-sectional area of ​​soft tissue.

[0010]

[0010] Clause 5. The method according to any one of Clauses 1 to 4, wherein the multiple load conditions include multiple postures of an individual.

[0011]

[0011] Clause 6. The method according to any of Clauses 1 to 5, wherein multiple load conditions include multiple positions of an individual.

[0012]

[0012] Clause 7. The method according to any one of Clauses 1 to 6, wherein the soft tissue includes tendons, connective tissue, intervertebral discs, ligaments, or muscles.

[0013]

[0013] Clause 8. The method according to any one of Clauses 1 to 7, wherein the soft tissue injury model includes a finite element method model for characterizing the soft tissue.

[0014]

[0014] Clause 9. The method according to any one of Clauses 1 to 8, wherein the soft tissue injury model comprises at least two injury regimes, each of which comprises one of the following: an uninjured regime, a subtear injury regime, or a crack propagation regime.

[0015]

[0015] Clause 10. The method according to any one of Clauses 1 to 9, wherein the guidelines based on the soft tissue injury model include limitations on at least one of the following: soft tissue posture, number of repetitions of soft tissue movement, force applied to the soft tissue, duration of maintaining the soft tissue posture, duration of repetitions of soft tissue movement, or duration of force applied to the soft tissue.

[0016]

[0016] Clause 11. A system for obtaining material science properties of soft tissue for use in a damage model to improve injuries of an individual performing a process, the system comprising at least one electronic processor that executes instructions for performing a process including obtaining physical parameters characterizing the individual's soft tissue under each of a plurality of load conditions and fitting a soft tissue damage model based on the parameters, wherein injuries during the process are improved by implementing guidelines based on the soft tissue damage model.

[0017]

[0017] Clause 12. The method according to Clause 11, further comprising an ultrasonic device, wherein obtaining physical parameters includes measuring at least one parameter of soft tissue using the ultrasonic device.

[0018]

[0018] Clause 13. The method according to either Clause 11 or 12, wherein the ultrasonic device includes a shear wave ultrasonic device and the parameter includes the shear modulus.

[0019]

[0019] Clause 14. The method according to any one of Clauses 11 to 13, wherein the ultrasonic device includes a longitudinal ultrasonic device, and the parameters include at least one of Young's modulus or the cross-sectional area of ​​soft tissue.

[0020]

[0020] Clause 15. The method according to any one of Clauses 11 to 14, wherein multiple load conditions include multiple postures of an individual.

[0021]

[0021] Clause 16. The method according to any of Clauses 11 to 15, wherein multiple load conditions include multiple positions of an individual.

[0022]

[0022] Clause 17. The method according to any one of Clauses 11 to 16, wherein the soft tissue includes tendons, connective tissue, intervertebral discs, ligaments, or muscles.

[0023]

[0023] Clause 18. The method according to any one of Clauses 11 to 17, wherein the soft tissue injury model includes a finite element method model for characterizing the soft tissue.

[0024] Article 19. The method according to any one of Articles 11 to 18, wherein the soft tissue injury model includes at least two injury regimes, and each of the at least two injury regimes includes one of a non-injured regime, a sub-fracture injury regime, or a crack propagation regime.

[0025] Article 20. The method according to any one of Articles 11 to 19, wherein the guidelines based on the soft tissue injury model include restrictions on at least one of the posture of the soft tissue, the number of repetitions of the movement of the soft tissue, the force applied to the soft tissue, the duration of maintaining the posture of the soft tissue, the duration of the repetition of the movement of the soft tissue, or the duration of the force applied to the soft tissue.

[0026] Article 26. The above and / or other aspects and advantages will become more apparent and be more easily understood from the detailed description of the following examples in conjunction with the accompanying drawings. Brief Description of the Drawings

[0027] [Figure 1] It is a schematic hybrid diagram showing exemplary system elements and method steps according to various examples. [Figure 2] It is a schematic diagram showing various postures according to various examples. [Figure 3] It is a schematic diagram showing various positions according to various examples. [Figure 4] It is a flowchart showing an exemplary method for obtaining the material science properties of soft tissue for use in an injury model to improve the injury of an individual performing a process according to various examples. [Figure 5] It is a schematic diagram of a system for obtaining the material science properties of soft tissue for use in an injury model to improve the injury of an individual performing a process according to various examples. Mode for Carrying Out the Invention

[0028]

[0032] Next, exemplary embodiments will be described more fully with reference to the accompanying drawings. However, the examples of this disclosure can be embodied in many different forms and should not be construed as being limited to the examples described herein. Rather, these examples are provided so that this disclosure may be thorough and complete and so as to convey its scope to those skilled in the art. In the drawings, some details may be simplified and / or drawn to facilitate understanding rather than maintaining strict structural accuracy, detail, and / or scale.

[0029]

[0033] I. Introduction

[0034] This disclosure relates to methods, systems, and computer-readable media for collecting information used to develop models for determining and predicting soft tissue injuries. The models can apply physical and chemical principles related to the strength and resilience of human tissues to predict injuries. For example, the models can apply principles of materials science to human tissues based on new criteria such as dimensions (e.g., cross-sectional area of ​​soft tissue), forces (e.g., in various postures), stress distribution, combined stress, and soft tissue performance parameters (e.g., healthy state, healing, injury accumulation, injury). In examples, ultrasound and other technologies and devices can be used to obtain empirical measurements of physical parameters used to fit the models. In some applications, predictive models are used when addressing ergonomic issues related to tasks where guidelines should be communicated and established to prevent or mitigate potential injuries.

[0030]

[0035] While some examples presented herein relate to shoulder injuries and the supraspinatus tendon, the methods and related embodiments disclosed herein can also be applied to essentially any soft tissue, such as intervertebral discs, ligaments, tendons, and tendinous systems of interest, as well as to biomimetic applications such as the design of artificial tendons. Furthermore, essentially any tendon can be evaluated as part of the techniques disclosed herein. Tendons may include mammalian tendons, such as human tendons. Examples of tendons include the teres minor tendon, infraspinatus tendon, supraspinatus tendon, subscapularis tendon, deltoid tendon, biceps tendon, triceps tendon, brachioradialis tendon, supinator tendon, flexor carpi radialis tendon, flexor carpi ulnaris tendon, extensor carpi radialis tendon, extensor carpi radialis brevis tendon, iliopsoas tendon, obturator internus tendon, adductor longus tendon, adductor brevis tendon, adductor magnus tendon, gluteus maximus tendon, gluteus medius tendon, quadriceps, patellar tendon, hamstring tendons, sartorius tendon, gastrocnemius tendon, Achilles tendon, soleus tendon, tibialis anterior tendon, peroneus longus tendon, flexor digitorum longus tendon, and interosseous tendons. This includes the tendons of the flexor digitorum profundus, abductor digiti minimi, opponens pollicis, flexor pollicis longus, extensor tendons, abductor pollicis, flexor pollicis longus, flexor digitorum brevis, lumbrical tendons, abductor pollicis, flexor digitorum longus, abductor digiti minimi, oculi tendons, levator palpebrae superioris tendons, masseter tendons, temporalis tendons, trapezius tendons, sternocleidomastoid tendons, semispinalis capitis tendons, splenius capitis tendons, mylohyoid tendons, thyrohyoid tendons, sternohyoid tendons, rectus abdominis tendons, external oblique tendons, transversus abdominis tendons, latissimus dorsi tendons, erector spinae tendons, and combinations thereof. Therefore, using these examples, models can be developed to generate injury improvement guidelines for any activity involving any part of the body and any soft tissue.

[0031]

[0036] Furthermore, using the shoulders to perform tasks in the workplace presents challenges in extreme work environments. The positioning, function, and control of the hands—the most useful part of the human body for manual and tool-intensive assembly work—are made possible by the shoulder mechanism. The hands, and therefore the arms and shoulders, move for welding, painting, drilling, cutting, gutting fish, or handling materials. The system of tools, hands, and shoulders is often positioned overhead or in hard-to-reach places. The shoulder complex must support the weight of the arms, the tools held to perform the work, and the applied forces. Most manual work using tools involves tasks that are repeated many times during the work period. Shoulder injuries are not limited to those sustained through work. They often occur outside the workplace, for example, at home or while participating in sports or other human activities.

[0032]

[0037] The neutral position of the shoulder is when the upper arm is straight and hangs at the side of the body. Each time the shoulder moves away from the neutral position, the tendons are subjected to tensile forces, and stress is generated within the tendons. Each time the shoulder moves away from the neutral position, forces and repetitions occur, exposing the tendons to cumulative fatigue damage. Note that the term "fatigue" used throughout this disclosure is in the mechanical sense (structural deterioration due to repeated forces), not the physiological fatigue that prevents activity due to decreased muscle contraction force.

[0033]

[0038] Studies linking shoulder pain and rotator cuff injuries to workplace factors have identified overhead work (defined as elbows above shoulders), applied force, repetitive movements, and physical load as significant contributing factors. However, the quality of these studies has varied, and the evidence has not consistently demonstrated a significant dose-response relationship.

[0034]

[0039] As a result, currently published guidelines on the risk of shoulder strain injuries are insufficient for use in occupational ergonomic injury prevention programs. Existing guidelines are inadequate because they are based on previous workplace studies that focused on self-reported pain and discomfort. They are even more inadequate because they do not provide clear and acceptable limits for shoulder-based work activities in the workplace, and they do not account for the interaction of posture, force, and repetition, nor the interaction of posture, force, repetition, duration, and vibration. Instead, existing guidelines recommend reducing or eliminating postures where the shoulder is overhead or the shoulder is extended. Professionals are faced with a degree of unknown risk. Such unknown risks limit the scope for solutions for effective interventions.

[0035]

[0040] In some industries, eliminating repetitive, cumbersome, or strainful shoulder use is impossible, but it can be mitigated. Where there is no sufficient risk threshold, the question remains: how much do these risk factors need to be reduced to improve or prevent injury? The issue is further complicated by the fact that this type of work may involve many repetitive movements (e.g., painting) and / or forces (e.g., drilling) and / or loads (e.g., welding). Therefore, guidelines may take into account the interaction of risk factors and work / rest cycles.

[0036]

[0041] Given that epidemiological data alone cannot establish causality, an alternative approach is needed. The models and related embodiments disclosed herein fill many of the gaps that conventional epidemiological studies have failed to fill, instead using fatigue models of cumulative injury to predict and prevent injury in certain embodiments.

[0037]

[0042] This is a novel approach to model and characterize stresses on musculoskeletal soft tissues (connective tissue, shoulder tendons, intervertebral discs, ligaments, muscles, etc.) exposed to various stimuli and conditions, thereby revealing the fatigue failure characteristics of soft tissues. The model's results can be used to characterize "good," "bad," and "worse" postures during work or other daily activities (hobbies, sports, etc.). Using the model involves collecting and interpreting physical parameters (such as Young's modulus, shear modulus, strain, and cross-sectional area of ​​the tissue) under various stimuli and conditions within the body. This model is based on the methodology of materials science.

[0038]

[0043] Fatigue models for soft tissue materials can be provided as finite element representations of the material behavior of soft tissues (such as tendons). The reliability of the models is expected to increase by incorporating nonlinear behavior and adding complex loads and soft tissue vibration / fatigue cycles. This has been shown to lead to complex effects that contribute to injury with distinct multipliers, previously unknown or misunderstood in the field of ergonomics.

[0039]

[0044] The results of the modeling can determine criteria that can be used to create guidelines for systematizing activities so that subjects are not exposed to overuse that could lead to injury if not improved. Using the model, exposure limits can be set, and usable work / rest cycles can be created to predict and prevent overuse injuries, which can bring about significant changes to current approaches to injury improvement and mitigation. This enables analyses and final results that were not previously possible (not possible with existing knowledge or models). The examples disclosed herein are advantageous for heavy industry (especially when overhead work, repetition, and force are present) and sports. Using the examples, work methods that exceed common-sense thresholds of tendon strain or stress can be redesigned, work-rest cycles can be created based on collagen damage and repair rates, individuals for whom the model is not conservative can be identified, and strength training can be implemented to improve tendon material properties.

[0040]

[0045] In short, it is necessary to analyze and determine what factors lead to musculoskeletal and soft tissue injuries. Specifically, it is necessary to determine the parameters used to create the injury models disclosed herein. Such parameters include, for example, one or more of the following: Young's modulus, shear modulus, strain, and cross-sectional area of ​​the soft tissue. As described in detail herein, ultrasound surveys can estimate the material acoustic properties of biological materials in vivo, which can be correlated with certain mechanical properties such as Young's modulus. These and other methods are described in detail below.

[0041]

[0046] II. Exemplary Methods

[0047] Figure 1 is a schematic hybrid diagram 100 showing exemplary system elements and method steps in various examples. At the center of Figure 100 is the damage model 102.

[0042]

[0048] A. Damage models and damage regimes

[0049] Model 102 can consist of one or more of the following sequential soft tissue injury regimes: (1) no injury, (2) accumulation of subtear injury (microcracks), (3) accumulation of injury in the form of growing cracks or tears, cellular matrix damage, or other forms of biological injury, or (4) a state of catastrophic destruction or separation of tendon structure. Model 102 can determine when a transition occurs from one injury regime to the next in the sequence.

[0043]

[0050] To this end, Model 102 uses damage regime information 112. Damage regime information 112 can be in the format of a computer file, for example, tab-separated or comma-separated values ​​(CSV) format. Damage regime information 112 can be obtained during use of the example by being read by a computer from a persistent electronic storage device or by the data being entered into a file format and stored on the computer, as is not an exhaustive example.

[0044]

[0051] Damage regime information 112 can be generated based on empirical measurements of the material science properties of soft tissue, for example, on ultrasound data, computed tomography (CAT) scan data, magnetic resonance imaging (MRI) scan data, fracture test data, cadaver material, animal material, polymer surrogate material, molecular dynamics modeling (MDM) data, publicly available data, or a combination thereof.

[0045]

[0052] Damage regime information 112 may take the form of a separate set of damage regime information for each damage regime. Each set of damage regime information can quantify the number of repetitions at a given stress for the soft tissue to transition from each damage regime. For example, the first set of information can quantify the number of repetitions per given stress for the soft tissue to transition from the first damage regime. The second set of information can quantify the number of repetitions per given stress for the soft tissue to transition from the second damage regime. In an example including a third damage regime, the third set of information can quantify the number of repetitions per given stress for the soft tissue to transition from the third damage regime.

[0046]

[0053] Each injury regime information can be in the form of a curve that quantifies the number of repetitions at a given stress for the soft tissue to transition out of each injury regime, where the curve is, for example, independent of stress and dependent on repetitions. For example, according to various examples, each piece of information can be in the form of an S-N curve. When stored on a computer, such information can be in the form of a set of ordered pairs (S, N), where S represents stress and N represents the number of repetitions for transitioning out of each regime.

[0047]

[0054] In various examples, the first injury regime may be a no-injury regime, the second injury regime may be a subtear injury regime, and in examples including that, the third injury regime may be a crack propagation regime. (Note that, in various examples, not limited to those explicitly shown, any combination of at least two injury regimes can be used.) The no-injury regime can represent a situation in which micro-injuries (e.g., subtears) occur in the soft tissue at substantially the same rate as healing. A transition from the no-injury regime can represent the accumulation of subtears at a rate faster than the healing rate for each piece of soft tissue. The subtear regime can represent a situation in which micro-injuries (e.g., subtear injuries) are accumulating, but macroscopic cracks have not yet formed. A transition from the subtear regime can represent the formation of macroscopic cracks. The crack propagation regime can represent a situation in which cracks have formed and are propagating through the soft tissue. A transition from the crack propagation regime can represent the complete rupture of the soft tissue.

[0048]

[0055] In cases incorporating either or both of the no-injury regime and the sub-tear regime, it should be noted that soft tissue damage to the subject can be predicted before the subject becomes aware of the injury. For example, the soft tissue in these regimes may be damaged, but it does not cause pain or discomfort to the subject.

[0049]

[0056] It should be noted that soft tissues such as tendons behave like materials with predictable fatigue failure at a given stress level and cycle, but they can also self-repair. When people engage in physical activity, the repeated stress on soft tissues results in small tears, which are referred to herein as microtraumas or subtears. Subtears themselves do not harm the body, as the body repairs itself and becomes stronger if given sufficient recovery time. This is the fundamental benefit of exercise. If the recovery time is insufficient, the tendon is damaged, and eventually injury occurs. Therefore, model 102 can take into account the rest period during which the soft tissue self-repairs. Thus, injury regime information 112 is also based on healing data 116. Healing data 116 may include data representing the healing rates of various soft tissues. For example, healing data 116 may include the respective healing rates of various tendons. Also, healing data 116 may be arranged according to demographic information. For example, healing data may include the healing rate of the supraspinatus tendon for various age groups (e.g., 18-30 years, 30-40 years, 40-50 years, and 50-60 years).

[0050]

[0057] The damage model 102 can determine whether damage has occurred or predict that damage will occur by evaluating the task information 114 in light of its damage estimation and damage prediction. The task information 114 can be in the format of a computer file, for example, tab-separated or comma-separated values ​​(CSV) format. In non-limiting examples, the task information 114 can be obtained by being read by a computer from a persistent electronic storage device, or by inputting the data into a file format and storing it on a computer.

[0051]

[0058] Task information 114 can represent the exposures that a subject may (or has) accumulated in the process of completing a task that forms part of an overall process, such as a manufacturing process. The exposures can take the form of the number of repetitions, the corresponding time intervals in which the repetitions are performed, and a description of the movements in each repetition (e.g., in descriptive form). As some examples show, task information 114 can consist of multiple types of movements.

[0052]

[0059] To evaluate the task information 114 in light of the damage estimation and damage prediction of Model 102, the combined stress 104 for each cycle under multiple load conditions can be determined. As described in detail below, this data can be combined with the task information 114 and the damage regime information 112 to determine the cumulative damage over the course of the task.

[0053]

[0060] B. Combined stress

[0061] To determine whether soft tissue damage has occurred or is about to occur, the damage model 102 uses task information 114, which shows the repeated injury exposures the subject has suffered (or will suffer) while performing a task, compared with damage regime information 112. To do this, the damage model 102 first determines the combined stress 104 for each movement represented in the task information 114. Then, based on the combined stress 104 and the task information 114, and using the damage regime information 112, the model 102 determines whether the soft tissue has transitioned (or will transition) to a different damage regime.

[0054]

[0062] The combined stress 104 can be determined by first determining the combined forces. The term “combined forces” refers to the combination of forces acting on soft tissue during work, including posture, position, vibration, tool weight, force vector applied to the hand, and arm weight. Tensile forces are associated with the shoulder, but other soft tissues, such as intervertebral discs, can be subjected to compressive forces. Other types of soft tissue can be subjected to both compressive and tensile forces. Forces can be determined by observation and empirical measurements, as detailed below, or by estimation and / or modeling techniques such as finite element modeling (FEM) and / or electromyography (EMG). For example, forces can be expressed in Newtons, and stresses can be expressed in megapascals (MPa).

[0055]

[0063] Stress increases under specific postures and load conditions. Certain muscle / tendon structures have relationships or correlations with the tissues involved in the task. Therefore, stress can be determined under several different load conditions (e.g., posture and / or position). Posture and position are illustrated with reference to Figures 2 and 3.

[0056]

[0064] Figure 2 is a schematic diagram showing various postures 202 by various examples. "Posture" can refer to the qualitative characterization of a subject's body or a part thereof. Posture can be defined by the relative position of identified landmarks. For example, a particular posture called "overhead work" can be defined as a situation where the subject's elbows are above their shoulders. In general, posture can be defined qualitatively, so that the position of the body can be observed and compared to another observation or position. The position of a subject (or a part of the subject's body) can be determined by observational studies by an ergonomist or industrial engineer, according to various examples.

[0057]

[0065] Figure 3 is a schematic diagram showing various positions 302 by various examples. Here, “position” can refer to the quantitative characterization of the subject’s body or a part thereof. For example, a position can be defined using measuring instruments in units such as length, angle, and xyz coordinates. For example, the position of a tendon is defined by coordinates (0cm, 5cm, 1cm), where the origin (0cm, 0cm, 0cm) is where the tendon attaches to the humerus, and the coordinates correspond to positions in the following planes: x = sagittal plane, y = transverse plane, z = coronal plane. As shown in Figure 3, for example, several virtual shelves distributed throughout the entire three-dimensional space around (e.g., surrounding) the subject can define multiple positions of the subject’s arm and hand.

[0058]

[0066] The position and orientation of a subject (or part of the subject's body) can be determined using motion tracking 111, according to various examples. Such motion tracking 111 can be performed by a motion tracking system that continuously tracks the subject's limbs or other body parts in three-dimensional space using transmitters or reflectors using light (e.g., infrared), sound waves (e.g., ultrasound), or radio frequency (RF), and corresponding sensors. Such sensors are distributed three-dimensionally in the space where the subject is located, and the transmitters / reflectors may be attached to the subject. This description represents "outside-in" tracking. Alternatively, according to some examples, the motion tracking system can utilize "inside-out" tracking, where the sensors are placed on the subject and the transmitters / reflectors are distributed in space. Some examples utilize motion tracking that does not involve transmitters or reflectors. In such examples, one or more video cameras and, for example, computer vision analysis can be used to track movement. Regardless of the type, the motion tracking system can determine orientation by matching a predetermined location of the subject's body or part of it with data associated with various locations. A motion tracking system can determine a subject's position by specifically measuring the distance associated with their movement.

[0059]

[0067] Returning to the explanation of Figure 1, the combined stress 104 of a single cycle can be determined by dividing the combined force in that cycle by the area of ​​the cross-section of the affected soft tissue. Therefore, determining the combined stress 104 may involve determining the cross-sectional area of ​​the affected soft tissue. In the example, various methods can be used to determine such an area.

[0060]

[0068] In some examples, the cross-sectional area of ​​the affected soft tissue is determined based on a geometric model 108. Such a model can approximate the shape of the cross-sectional area as circular, elliptical, or another two-dimensional geometric shape. The geometric model 108 can be based on past studies on the shapes of various soft tissue cross-sections. Furthermore, the geometric model 108 can consist of the subject's age, sex, size, and other specific demographic strata, based on past empirical measurements made on individuals with similar characteristics. Thus, the soft tissue cross-sectional area of ​​the geometric model 108 can be based on the average cross-sectional area of ​​various soft tissue types, specific cross-sectional areas for each demographic combination (e.g., sex, age, gender, height, weight, etc.), or a combination of such data.

[0061]

[0069] In some examples, ultrasound 106 is used to determine the cross-sectional area of ​​the affected soft tissue. For example, longitudinal ultrasound can be used to directly measure the dimensions of the cross-sectional area using a longitudinal ultrasound device. Alternatively, or in addition to longitudinal ultrasound, the Young's modulus of the soft tissue can be measured using longitudinal ultrasound. The stress can then be calculated from the measured Young's modulus. Whether it is the cross-sectional area or the Young's modulus, the measurement can be performed in various positions and orientations 110. This is helpful for a more accurate stress estimation because soft tissues such as tendons usually change their properties with changes in position; for example, tendons tend to stiffen as they are stretched.

[0062]

[0070] Alternatively, or in addition, as shown in some examples, shear wave ultrasound can be used with a shear wave ultrasound device. For example, shear wave ultrasound can be used to measure the shear modulus. Then, stress can be calculated from the measured shear modulus. In this case as well, these measurements can be calculated for various positions and orientations 110.

[0063]

[0071] C. Damage prediction and guideline generation

[0072] Based on the combined stress 104, the damage model 102 can determine whether damage has occurred or is about to occur. The determination can utilize the material science properties of the soft tissue. According to some examples, the determination can be performed as follows. For the sake of explanation, the determination is described in terms of prediction. However, this determination can also be used to detect damage that has already occurred. Firstly, the combined stress 104 can be determined as described above. In detail, the combined stress 104 for each iteration (and / or each subsequent iteration) can be determined. Secondly, the cumulative combined stress can be calculated by multiplying the combined stress 104 for a particular iteration by the number of iterations that have been performed or are scheduled to be performed, as indicated in the task information 114. Thirdly, the cumulative combined stress is compared with damage regime information 112, as indicated by the healing data 116. For example, in the case of cumulative stress, where each represents R repetitions of stress level S, the cumulative stress ΣS can be considered an independent variable in the information representing the current injury regime of the soft tissue, and a corresponding dependent variable R' relating to the number of repetitions for transition from the injury regime can be identified. Fourth, the number of repetitions R' of the identified dependent variable is compared with the number of repetitions R described in the task information 114. If the former is greater than the latter, the soft tissue is predicted to remain in the current injury regime, and therefore no additional injury is predicted. However, if the former is less than or equal to the latter, the soft tissue is predicted to transition from the respective injury regime. In that case, the soft tissue is predicted to be injured. Thus, the soft tissue is predicted to be injured when the number of repetitions R described in the task information 114 at stress level S satisfies or exceeds the number of repetitions R' corresponding to S, which is described in the injury regime information 112 notified by the healing data 116, and which characterizes the current injury regime for transition from the current injury regime.

[0064]

[0073] This process may include multiple tasks, as shown in task information 114. For example, the product of the number of repetitions and the stress level can be summed. This sum can be compared with the damage regime information 112. If the sum is greater, the soft tissue is predicted to be damaged, i.e., to transition to a new damage regime. Otherwise, the soft tissue is predicted to remain in its current damage regime.

[0065]

[0074] An example of using Model 102 to predict damage (or to determine if damage has already occurred) is shown. According to this example, task information 114 includes the following:

[0075] Repeats of Task A: 50

[0076] Repeat Task B: 500

[0077] Repeat Task C: 5000

[0066]

[0078] The combined force in each iteration of the task may be determined as described in task information 114 or as part of calculating the combined stress 104, as follows:

[0079] Force in Task A: 150N

[0080] Force in Task B: 100N

[0081] Force for Task C: 50N

[0067]

[0082] The stress is the force divided by the cross-sectional area of ​​the tendon, which can be determined from ultrasound 106 and / or geometric model 108. In this example, the cross-sectional area is 50 mm². 2 Therefore, per iteration, the stress for task A is 3 MPa, the stress for task B is 2 MPa, and the stress for task C is 1 MPa. In this example, the damage regime information may indicate that the transition from the undamaged regime occurs at 1000 cycles at 4 MPa (this is a single point along the curve).

[0068]

[0083] The stress from the task can be compared to the limit of the no-damage regime, such as 3MPa*50 + 2MPa*500 + 1MPa*5000 > 4MPa*1000. This means that it exceeds the no-damage regime. Therefore, calculations must be performed up to the next regime (e.g., subtear), and in some cases, up to the next regime, and so on, up to the fracture regime. Note that if multiple tasks are combined with rest periods between them, healing data 116 may also be applied (e.g., percentage reduction in exposure, shift to a lower point on the curve, etc.).

[0069]

[0084] In this example, the calculation shown above provides a point solution (only one number and one answer) for one iteration. To increase the confidence of the model, this iteration can be run many times and sampled from, for example, the distribution of soft tissue shape, the distribution of forces acting on soft tissue, and the distribution of potential variability in the iterations. For example, this can be a model run multiple times with slightly different stochastic inputs, similar to a Monte Carlo simulation. This provides a risk output with several boundaries or bands around it (e.g., a 95% confidence interval). Optionally, other variables, such as demographic layers, can also be added to the model.

[0070]

[0085] Based on the injury model, an example may be created to develop guidelines 118 for avoiding or mitigating soft tissue injury. As used herein, the term “guidelines” includes an evidence-based set of recommended limits relating to one or more of the following: force (e.g., vibration, tool weight, force vector applied to the hand, arm weight, etc.), posture, position, frequency, duration, and / or recovery, which are intended to protect human tissue materials from the risk of injury due to tendon injury during human activities such as manufacturing or other processes. Generally, each guideline may reduce the number of repetitions and / or the amount of stress corresponding to an action in task information 114. Thus, each guideline may specify the posture or position of the soft tissue, the number of repetitions of a given movement of the soft tissue, the force applied to the soft tissue, the duration of maintaining a given posture or position of the soft tissue, the duration of a (single) repetition of a given movement of the soft tissue, the duration of a given force applied to the soft tissue, or a combination thereof. Such parameters may be specified such that the calculations above predict that no injury will occur. The parameters thus specified may form all or part of a guideline.

[0071]

[0086] Generally, guidelines suggest that stress on soft tissue can be reduced by reducing the force on the soft tissue in one of several ways. The force on soft tissue can be a composite force acting on the soft tissue, and the force is a result of factors such as posture (or position), weight (e.g., the weight of an arm and / or the weight of holding an object such as a tool), applied force vector (e.g., pushing with a hand), and vibration (due to holding a vibrating object such as a hand tool). According to some examples, the force can be reduced by imposing restrictions on any of the above parameters.

[0072]

[0087] Forces on soft tissues can be reduced, or in addition, by imposing restrictions on the position and / or posture of the subject's body or parts thereof, thereby influencing the position and / or posture of the soft tissues. According to various examples, guidelines may include restrictions on at least one of the position and / or posture of the soft tissues.

[0073]

[0088] Alternatively, or in addition, forces acting on soft tissues can be reduced by limiting the duration of movement, position, or posture. That is, guidelines may impose limits on the duration of soft tissue maintaining a given posture, the duration of soft tissue maintaining a given position, the duration of repeated movements of soft tissue, and / or the duration of a given force applied to soft tissue, or any combination thereof.

[0074]

[0089] According to some examples, guidelines may include imposing rest periods. Such examples may utilize representations of the healing process that counteracts micro- or major damage. The rest period may represent sufficient time for such healing processes to counteract the accumulated damage.

[0075]

[0090] The created guidelines can be output and used in processes such as manufacturing processes. Guidelines can be output in various formats. According to some examples, guidelines can be output in a narrative format using pre-created narrative templates. For example, if calculations show that the number of repetitions needs to be reduced from 1000 to 725, the guideline could be a template that reads, "The number of repetitions of action X needs to be reduced from Y to Z," into which these numbers can be entered, with X replaced by the action description, Y by 1000, and Z by 725. The formatted guidelines can be output by displaying them on a computer monitor, by email, or by other means of providing information to individuals or processes.

[0076]

[0091] Implementing guidelines in a process can include providing guidelines to assembly line workers, for example, if the process is a manufacturing process. Workers can then modify their tasks accordingly. In an example where the process is an exercise training process, guidelines can be provided to trainers, who can then modify the athletes' training plans accordingly. Furthermore, guidelines can be used to design production systems, products, work tasks, training plans, and so on.

[0077]

[0092] Figure 4 is a flowchart illustrating an exemplary method 400 for obtaining material science properties of soft tissue for use in injury models to improve injuries to individuals performing a process, using various examples. Method 400 can reduce the likelihood of injury to a person performing a process by utilizing the material science properties of soft tissue. For example, each worker may have one or more tasks that form part of a manufacturing process, for example, on an assembly line. Each worker's task can be modified by one or more guidelines created by Method 400. Alternatively, Method 400 can be used to improve repetitive stress injuries in athletes performing a training program, for example. The athlete may perform one or more exercises that constitute part of the training program. The exercises can be modified by one or more guidelines created by Method 400. In general, Method 400 can be implemented to improve repetitive stress injuries in any type of process involving repetitive movements by a person, not limited to manufacturing or exercise processes.

[0078]

[0093] Method 400 can be used to improve various soft tissue injuries. According to some examples, Method 400 can be used to improve injuries to tendons or tendon complexes. Examples of such tendons and tendon complexes are shown above with reference to Figures 1-3. Alternatively, Method 400 can be used to improve injuries to connective tissue or musculoskeletal soft tissue. Generally, non-limited examples of soft tissues to which the method can be performed include tendons, tendon complexes, intervertebral discs, and ligaments.

[0079]

[0094] Method 400 may be carried out using a system 500 as shown and described below with reference to Figure 5. Method 400 includes non-computer actions that bring about improvements in the field of industrial hygiene. Such actions include, for example, acquiring physical parameters using ultrasonic and / or motion detection devices.

[0080]

[0095] In 402, method 400 obtains physical parameters characterizing the individual's soft tissue under each of several load conditions. These physical parameters may include dimensions of the soft tissue, such as cross-sectional area, Young's modulus, and / or shear modulus. These physical parameters may be obtained using an ultrasonic device, such as a longitudinal or shear wave ultrasonic device, as described above with reference to Figure 1. These physical parameters may also be obtained using a motion tracking system, as described above with reference to Figure 1. These physical parameters may be obtained for multiple load conditions, e.g., for various positions and / or orientations. Essentially arbitrary physical parameters that contribute to determining the composite stress (e.g., composite stress 104 shown and described above with reference to Figure 1) may be obtained.

[0081]

[0096] In 404, method 400 involves fitting a soft tissue injury model based on the physical parameters of 402. Fitting the model may involve adapting the model to the physical parameters of 402. The soft tissue injury model may be based on finite element method (FEM) simulations of soft tissue. The soft tissue injury model may consist of at least two injury regimes, e.g., no-injury regime, sub-tear regime, and crack propagation regime, as shown and described above with reference to Figure 1.

[0082]

[0097] In 406, Method 400 improves the risk of injury to subjects performing the process under consideration. To do so, Method 400 may include the creation of guidelines and the implementation of the guidelines in the process. The guidelines may include limits on at least one of the following, as shown and described above with reference to Figure 1: the posture of the soft tissue, the number of repetitions of a given movement of the soft tissue, the force applied to the soft tissue, the duration of maintaining a given posture of the soft tissue, the duration of repetitions of a given movement of the soft tissue, or the duration of a given force applied to the soft tissue. The guidelines can be implemented, for example, by providing them to workers on an assembly line. Thus, by following the guidelines, the risk of soft tissue injury to subjects due to repetitive stress injuries is improved.

[0083]

[0098] III. Exemplary Systems and Computer-Readable Media

[0099] Figure 5 is a schematic diagram of a system 500 for obtaining soft tissue material science properties for use in injury models to improve injuries of individuals performing the process, by various examples. For example, Figure 5 shows various hardware, software, and other resources that may be used in the implementation of method 400 by the disclosed examples.

[0084]

[0100] In the example shown, system 500 includes a computer 501, an ultrasonic device 516 (including an ultrasonic transducer 518), and a motion tracking device 502 (including a sensor 520, e.g., a camera, and a transmitter or reflector 524 attached to the body of a subject 522). The ultrasonic device 516 may be, for example, a shear wave ultrasonic device or a longitudinal wave ultrasonic device. The computer 501 may be integrated into one or more servers, clusters, or other computers or hardware resources, or may be implemented using cloud-based resources. The computer 501 includes volatile memory 514 and persistent memory 512, the latter of which can store computer-readable instructions, and the computer 501 is configured to at least partially perform a method (e.g., method 400 as shown and described herein) when executed by an electronic processor 510. Computer 501 is communicatively coupled to the ultrasonic device 516 and the motion tracking device 502 via a network interface 508, such as Ethernet or a wireless data connection, which can communicate over one or more networks 504, such as the Internet or other public or private networks. According to some examples, data from the ultrasonic device 516 and / or the motion tracking device 502 is permanently stored on a computer communicatively coupled to computer 501 via network 504 and retrieved by computer 501. Computer 501 also includes a monitor on which generated guidelines may be displayed. Other configurations of the system 500, associated network connections, and other hardware, software, and service resources are possible.

[0085]

[0101] While the foregoing disclosure has been described in some detail for clarity and understanding, it will be apparent to those skilled in the art that various changes in form and detail can be made without departing from the true scope of the disclosure and can be implemented within the scope of the attached claims. For example, all methods, systems, and / or components or other embodiments thereof can be used in various combinations. All patents, patent applications, websites, other publications or documents, etc., referenced herein are incorporated by reference in whole for all purposes as if each individual item were specifically and individually indicated to be incorporated by reference.

Claims

1. 1. A method (400) for obtaining material science properties of soft tissue for use in an injury model for ameliorating injury in an individual performing a process, comprising: obtaining (402) physical parameters characterizing the soft tissue of the individual under each of a plurality of loading conditions; Fitting (404) a soft tissue damage model (102) based on the parameters; and Improving injury during execution of said process (406) by implementing guidelines (118) based on said soft tissue injury model; The method includes:

2. The method of claim 1 , wherein obtaining the physical parameter comprises measuring at least one parameter of the soft tissue using an ultrasound device (516).

3. the ultrasound device comprises a shear wave ultrasound device and the parameter comprises a shear modulus; and / or The method of claim 2 , wherein the ultrasound device comprises a longitudinal wave ultrasound device and the parameters include at least one of a Young's modulus or a cross-sectional area of ​​the soft tissue.

4. The method of claim 1 , wherein the plurality of loading conditions comprises a plurality of postures (110) of the individual and / or a plurality of positions of the individual.

5. The method of claim 1 , wherein the soft tissue comprises a tendon, connective tissue, intervertebral disc, ligament, or muscle.

6. The method of claim 1 , wherein the soft tissue damage model comprises a finite element model characterizing the soft tissue.

7. 7. The method of claim 1, wherein the soft tissue damage model comprises at least two damage regimes, each of the at least two damage regimes comprising one of an undamaged regime, a sub-fracture damage regime, or a crack propagation regime.

8. 8. The method of claim 1 , wherein the guidelines based on the soft tissue damage model include limitations on at least one of the following: posture of the soft tissue, the number of iterations of the soft tissue movement, the force applied to the soft tissue, the duration of maintaining the soft tissue posture, the duration of the iterations of the soft tissue movement, or the duration of the force applied to the soft tissue.

9. 1. A system (500) for obtaining material science properties of soft tissue for use in an injury model for ameliorating an injury in an individual performing a process, the system comprising: obtaining (402) physical parameters characterizing the soft tissue of the individual under each of a plurality of loading conditions; and Fitting (404) a soft tissue damage model (102) based on the parameters; at least one electronic processor (510) for executing instructions to perform a process including Implementing guidelines (118) based on the soft tissue injury model improves (406) injury when performing the process.

10. 10. The system of claim 9, further comprising an ultrasound device (516), and wherein obtaining the physical parameter comprises measuring at least one parameter of the soft tissue using the ultrasound device.

11. the ultrasound device comprises a shear wave ultrasound device and the parameter comprises a shear modulus; and / or The system of claim 10 , wherein the ultrasound device comprises a longitudinal wave ultrasound device and the parameters include at least one of a Young's modulus or a cross-sectional area of ​​the soft tissue.

12. The system of claim 9 , wherein the plurality of loading conditions comprises a plurality of postures (110) of the individual and / or the plurality of loading conditions comprises a plurality of positions of the individual.

13. The system of claim 9 , wherein the soft tissue comprises a tendon, connective tissue, intervertebral disc, ligament, or muscle.

14. The system of claim 9 , wherein the soft tissue damage model comprises a finite element model characterizing the soft tissue.

15. A system described in any one of claims 9 to 14, wherein the soft tissue damage model includes at least two damage regimes, each of the at least two damage regimes including one of an undamaged regime, a sub-fracture damage regime, or a crack propagation regime.

16. 16. The system of claim 9, wherein the guidelines based on the soft tissue damage model include limitations on at least one of the following: posture of the soft tissue, number of repetitions of the soft tissue movement, force applied to the soft tissue, duration of maintaining the soft tissue posture, duration of repetitions of the soft tissue movement, or duration of force applied to the soft tissue.

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