Clinical commentary: pathogenesis of cumulative trauma disorder

Multiple Concurrent Decompressions for the Treatment of Upper Extremity Pain

Purpose

Neuropathic pain can be life altering and difficult to treat. Nerves can be compressed along their path in the upper extremities, resulting in chronic neuropathic pain. This study was performed to evaluate the effectiveness and safety of multiple concomitant distal nerve decompressions for the treatment of upper extremity nerve pain.

Methods

A retrospective review of patients from a single surgeon's academic practice was performed to identify those undergoing nerve decompressions for an indication of "pain" as the referring diagnosis between April 2020 and June 2021. The primary outcomes included patient-reported severity of pain using the Visual Analog Scale and quality-of-life measures, including level of frustration, depression, and impact on quality of life attributable to pain on a similar 0-10 Likert scale. Complications, if any, were also determined.

Results

Eleven patients were identified to have undergone multiple concurrent nerve decompressions for the indication of upper extremity pain. All sites chosen for decompression were found to be provocative, ie, elicited increased pain on examination with compression. The median number of decompressions performed was 5 (interquartile range, 4-6), ranging from 3 to 7. The mean follow-up time was 5 months (SD, 3.43 months). The average pain over the last month and the average pain over the past week had significant improvement at the final follow-up, and there was a statistically significant decrease in the patient-reported mean impact of pain on quality of life following decompressions (preoperative, 5.8; postoperative, 3.6; P = .017; 95% confidence interval, 0.2-4.3). No complications were identified.

Conclusions

Performing multiple concomitant nerve decompressions of the upper extremities is safe and effective in the treatment of chronic neuropathic pain following upper extremity trauma.

Type of study/level of evidence

Therapeutic IV.

Proximal Median Nerve Compression in the Differential Diagnosis of Carpal Tunnel Syndrome

Carpal tunnel syndrome (CTS) is the most common median nerve compression neuropathy. Its symptoms and clinical presentation are well known. However, symptoms at median nerve distribution can also be caused by a proximal problem. Pronator syndrome (PS) and anterior interosseous nerve syndrome (AINS) with their typical characteristics have been thought to explain proximal median nerve problems. Still, the literature on proximal median nerve compressions (PMNCs) is conflicting, making this classic split too simple. This review clarifies that PMNCs should be understood as a spectrum of mild to severe nerve lesions along a branching median nerve, thus causing variable symptoms. Clear objective findings are not always present, and therefore, diagnosis should be based on a more thorough understanding of anatomy and clinical testing. Treatment should be planned according to each patient's individual situation. To emphasize the complexity of causes and symptoms, PMNC should be named proximal median nerve syndrome.

Aberrant Neuronal Activity in a Model of Work-Related Upper Limb Pain and Dysfunction

Work-related musculoskeletal disorders associated with intense repetitive tasks are highly prevalent. Painful symptoms associated with such disorders can be attributed to neuropathy. In this study, we characterized the neuronal discharge from the median nerve in rats trained to perform an operant repetitive task. After 3-weeks of the task, rats developed pain behaviors and a decline in grip strength. Ongoing activity developed in 17.7% of slowly conducting neurons at 3-weeks, similar to neuritis. At 12-weeks, an irregular high frequency neuronal discharge was prevalent in >88.4% of slow and fast conducting neurons. At this time point, 8.3% of slow and 21.2% of fast conducting neurons developed a bursting discharge, which, combined with a reduction in fast-conducting neurons with receptive fields (38.4%), is consistent with marked neuropathology. Taken together, we have shown that an operant repetitive task leads to an active and progressive neuropathy that is characterized by marked neuropathology following 12-weeks task that mainly affects fast conducting neurons. Such aberrant neuronal activity may underlie painful symptoms in patients with work-related musculoskeletal disorders. PERSPECTIVE: Aberrant neuronal activity, similar to that reported in this study, may contribute to upper limb pain and dysfunction in patients with work-related musculoskeletal disorders. In addition, profiles of instantaneous frequencies may provide an effective way of stratifying patients with painful neuropathies.

Physical work conditions and disparities in later life functioning: Potential pathways

Research in the US on the social determinants of reduced physical functioning at older ages has typically not considered physical work conditions as contributors to disparities. We briefly describe a model of occupational stratification and segregation, review and synthesize the occupational health literature, and outline the physiological pathways through which physical work exposures may be tied to long-term declines in physical functioning. The literature suggests that posture, force, vibration, and repetition are the primary occupational risk factors implicated in the development of musculoskeletal disorders, through either acute injuries or longer-term wear and tear. Personal risk factors and environmental and structural work characteristics can modify this association. In the long-term, these musculoskeletal disorders can become chronic and ultimately lead to functional limitations and disabilities that interfere with one's quality of life and ability to remain independent. We then use data on occupational characteristics from the Occupational Information Network (O*NET) linked to the 2019 American Community Survey (ACS) to examine disparities among sociodemographic groups in exposure to these risk factors. Occupations with high levels of these physical demands are not limited to those traditionally thought of as manual or blue-collar jobs and include many positions in the service sector. We document a steep education gradient with less educated workers experiencing far greater physical demands at work than more educated workers. There are pronounced racial and ethnic differences in these exposures with Hispanic, Black, and Native American workers experiencing higher risks than White and Asian workers. Occupations with high exposures to these physical risk factors provide lower compensation and are less likely to provide employer-sponsored health insurance, making it more difficult for workers to address injuries or conditions that arise from their jobs. In sum, we argue that physical work exposures are likely an important pathway through which disparities in physical functioning arise.

A primary care team approach to secondary prevention of work-related musculoskeletal disorders: Physical therapy perspectives

BACKGROUND

Among work-related conditions in the United States, musculoskeletal disorders (MSDs) account for about thirty-four percent of work absences. Primary care physicians (PCPs) play an essential role in the management of work-related MSDs. For conditions diagnosed as work-related, up to seventeen percent of cases are PCP managed; within these conditions, up to fifty-nine percent are diagnosed as musculoskeletal. Negative factors in treatment success confronting PCPs include time constraints and unfamiliarity with work-related MSDs. A multidimensional team approach to secondary prevention, where PCPs can leverage the expertise of allied health professionals, might provide a useful alternative to current PCP practices for the treatment of work-related MSDs.

OBJECTIVE

Provide the structure of and rationale for an "extended care team" within primary care for the management of work-related MSDs.

METHODS

A systematic literature search, combining medical subject headings and keywords, were used to examine eight peer-reviewed literature databases. Gray literature, such as government documents, were also used.

RESULTS

An extended care team would likely consist of at least nine stakeholders within primary care. Among these stakeholders, advanced practice orthopedic physical therapists can offer particularly focused guidance to PCPs on the evaluation and treatment of work-related MSDs.

CONCLUSIONS

A multidimensional approach has the potential to accelerate access and improve quality of work-related outcomes, while maintaining patient safety.

Association between carpal tunnel syndrome and trigger finger: a clinical and electrophysiological study

Background

Carpal tunnel syndrome is a prevalent mononeuropathy. Trigger finger is a flexor stenosing tenosynovitis. The aim of the study was to assess the concomitant occurrence of carpal tunnel syndrome and trigger finger in the same hand among patients presented with idiopathic carpal tunnel syndrome or idiopathic trigger finger. The study included 110 hands (75 patients) presented with carpal tunnel syndrome or trigger finger and 60 asymptomatic hands (46 apparently healthy individuals). Clinical assessment and neurophysiological evaluation were done.

Results

Regarding the presenting clinical complaints, there were 76 hands (69.1%) from 48 patients (64.0%) presented with idiopathic carpal tunnel syndrome. There 34 hands (30.9%) from 27 patients (36.0%) presented with idiopathic trigger finger. Classification of the patients into three groups depending on the final diagnosis: (I) carpal tunnel syndrome group, 57 hands (51.8%) with only carpal tunnel syndrome from 36 patients (48.0%); (II) trigger finger group, 25 hands (22.7%) with only trigger finger from 22 patients (29.3%); and (III) carpal tunnel syndrome with trigger finger group, 28 hands (25.5%) with both conditions from 24 patients (32.0%); and among them, seven patients had contralateral hand carpal tunnel syndrome only. The duration of complaints among the carpal tunnel syndrome with trigger finger group was significantly shorter than that in the other two groups. There were statistically significantly higher values of patient global assessment of hand symptoms and effect of hand symptoms on function and quality of life among the carpal tunnel syndrome with trigger finger group versus the other two groups. There was no statistically significant difference between the carpal tunnel syndrome with trigger finger group versus the carpal tunnel syndrome group regarding different classes of the Padua neurophysiological classification scale. The most common digit to have trigger finger was the middle finger in 19 hands (35.8%).

Conclusions

The concurrent presentation of idiopathic carpal tunnel syndrome and idiopathic trigger finger in the same hand is common. Each of them could be associated with the other one. The symptoms of one of them usually predominate the patient’s complaints. The identification of this association is essential for proper diagnosis and comprehensive management of patients presented with these conditions.

Update on the thoracic outlet syndrome and plexus brachial syndrome: Specific clinical examination (for all) and rehabilitation protocol

The diagnosis of uncomplicated forms of thoracobrachial outlet syndrome (TOS) and brachial plexus stretching syndrome (BPSS) is imprecise due to the lack of clear differentiation between dynamic vascular or neurological compression and brachial plexus stretching without vascular compression. After a review of literature, we propose and describe a simple way for clinical assessment of TOS, BPSS or association of both comprising 1 clinical sign and 2 manoeuvres. This clinical assessment can be performed by the medical doctor, the physiotherapist and the surgeon. The clinical diagnosis is essential because it will dictate the rehabilitation treatment. We propose and describe also a rehabilitation protocol comprising 10 phases with modulation of exercises according to clinical form (TOS, BPSS or association) and/or severity of symptoms. The physiotherapist has a capital role and is the guarantor of the effectiveness of the medical treatment. In France, a training is now available thanks to personal continuous development for diagnosis and treatment of TOS and BPSS. This is essential in order to propose an optimal care to patients.

Thoracic Outlet Syndrome: A Narrative Review

Thoracic outlet syndrome comprises a group of disorders that result in compression of the brachial plexus and subclavian vessels exiting the thoracic outlet. Symptoms include pain, paresthesia, pallor, and weakness depending upon the compromised structures. While consensus in diagnostic criteria has not yet been established, a thorough patient history, physical exam, and appropriate imaging studies are helpful in diagnosis. General first-line therapy for thoracic outlet syndrome is a conservative treatment, and may include physical therapy, lifestyle modifications, NSAIDs, and injection therapy of botulinum toxin A or steroids. Patients who have failed conservative therapy are considered for surgical decompression. This article aims to review the epidemiology, etiology, relevant anatomy, clinical presentations, diagnosis, and management of thoracic outlet syndrome.

Which Sung Pitch Range is Best for Boys During Voice Change?

The question of how and what boys should sing during adolescent voice change has challenged educators and choir leaders for the last century. As the larynx enlarges during adolescence, most boys will follow the descending pitch of their speaking voice and move to singing vocal parts with a lower pitch range. Occasionally a boy may continue to sing in his treble (soprano) range while his larynx is growing and his speaking pitch is lowering. There is much opinion on the wisdom of such practices, but until now there has been no quantifiable evidence to illustrate the discussion. The established historic and cultural practices can now be reassessed in the light of quantitative analyses of vocal function. This longitudinal case study used electroglottographic measures from one boy over a 3-year period to investigate the efficiency of vocal fold adductory behavior in both prechange and midchange singing. In the first recording, he is aged 10 years old and has an unchanged voice. In the second recording, he is aged 13 years old and has a speaking voice in the Cooksey Stage III of voice change. Up to and including the time of the second recording, he had chosen to remain singing exclusively in his treble (soprano) range. The comparison between the two recordings of the observed regularity and efficiency of vocal fold adduction suggests that singing in this pitch range has become less healthy and effective; this is also represented in the overall perceived vocal comfort levels heard in the recordings. The implications for educators are that the longitudinal development of singing habits will be enhanced for boys who move to singing with their new baritone range as their larynx grows, rather than remaining in a treble range.

Comparison of maximal isometric forearm supination torque in two elbow positions between subjects with and without limited forearm supination range of motion

Study Design: Cross-sectional comparison. Introduction: Forearm supination range of motion is often limited by short or stiff pronators. Many studies have examined maximal isometric forearm supination torque (MIFST). However, there is little research comparing MIFST in two elbow positions between subjects with and without limited forearm supination range of motion (LSR). Purpose of the Study: The purpose of this study was to compare MIFST in two elbow positions (90º flexed elbow, extended elbow) between subjects with and without LSR. Methods: Thirteen right-handed subjects (seven men, six women) with LSR and 13 age- and gender-matched healthy controls participated in this study. The forearm supination range of motion and MIFST were measured using a Smart KEMA system. Two-way repeated-measures analysis of variance was used to compare MIFST in two elbow positions between subjects with and without LSR. Results: No significant difference between groups (p > .05) was found. However, there was an interaction effect between elbow position and group on MIFST (p < .05). Independent t-tests were used to confirm the simple effects. In the LSR group, the value of MIFST was significantly lower in the elbow-extended position than in the group without LSR (p < .05). Conclusions: These findings indicate that elbow position should be considered when assessing the strength or increasing the strength of the supinator muscle, especially in patients with LSR.

Preferences in Sleep Position Correlate With Nighttime Paresthesias in Healthy People Without Carpal Tunnel Syndrome

BACKGROUND

Carpal tunnel syndrome has been associated with sleep position preferences. The aim of this study is to assess self-reported nocturnal paresthesias and sleeping position in participants with and without carpal tunnel syndrome diagnosis to further clinical knowledge for preventive and therapeutic interventions.

METHODS

A cross-sectional survey study of 396 participants was performed in young adults, healthy volunteers, and a patient population. Participants were surveyed on risk factors for carpal tunnel syndrome, nocturnal paresthesias, and sleep preferences. Binary logistic regression analysis was performed comparing participants with rare and frequent nocturnal paresthesias. Subanalyses for participants without carpal tunnel syndrome under and over 21 years of age were performed on all factors significantly associated with subclinical compression neuropathy in the overall population.

RESULTS

Thirty-three percent of the study population experienced nocturnal paresthesias at least weekly. Increased body mass index ( P < .001) and sleeping with the wrist flexed ( P = .030) were associated with a higher frequency of nocturnal paresthesias. Side sleeping was associated with less frequent nocturnal symptoms ( P = .003). In participants without carpal tunnel syndrome, subgroup analysis illustrated a relationship between nocturnal paresthesias and wrist position. In participants with carpal tunnel syndrome, sleeping on the side had a significantly reduced frequency of nocturnal paresthesias.

CONCLUSION

This study illustrates nocturnal paresthesias in people without history of carpal tunnel syndrome including people younger than previously reported. In healthy patients with upper extremity subclinical compression neuropathy, sleep position modification may be a useful intervention to reduce the frequency of nocturnal symptoms prior to developing carpal tunnel syndrome.

Cumulative trauma disorders: A review

BACKGROUND

Cumulative trauma disorder (CTD) is a term for various injuries of the musculoskeletal and nervous systems that are caused by repetitive tasks, forceful exertions, vibrations, mechanical compression or sustained postures. Although there are many studies citing incidence of CTDs, there are fewer articles about its etiology, pathology and management.

OBJECTIVE

The aim of our study was to discuss the etiology, pathogenesis, prevention and management of CTDs.

METHODS

A literature search was performed using various electronic databases. The search was limited to articles in English language pertaining to randomized clinical trials, cohort studies and systematic reviews of CTDs.

RESULTS

A total of 180 papers were identified to be relevant published since 1959. Out of these, 125 papers reported about its incidence and 50 about its conservative treatment.

CONCLUSIONS

Workplace environment, same task repeatability and little variability, decreased time for rest, increase in expectations are major factors for developing CTDs. Prevention of its etiology and early diagnosis can be the best to decrease its incidence and severity. For effective management of CTDs, its treatment should be divided into Primordial, Primary, Secondary and Tertiary prevention.

Comparison of muscle activity of wrist extensors and kinematics of wrist joint during wrist extension in automobile assembly line workers with and without lateral epicondylitis

BACKGROUND

Overuse of the extensor carpi radialis (ECR) may play a role in the development of lateral epicondylitis (LE). However, no studies have investigated the muscle activity ratio between the ECR and extensor carpi ulnaris (ECU) associated with the kinematics during wrist extension in workers with LE.

OBJECTIVE

We compared the ratio (ECR/ECU) of muscle activity between the ECR and ECU and the kinematics of the wrist during wrist extension between workers with and without LE.

METHODS

Fifteen automobile assembly line workers with LE and 15 workers without LE participated in this study. The ratio of muscle activity was measured using surface electromyography, and wrist kinematics were measured by a three-dimensional motion analysis system while the workers extended their wrists actively to the maximum range to which they did not feel uncomfortable.

RESULTS

Significantly greater ratios of muscle activity, ranges of radial deviation, and combined motion of radial deviation and extension (CMDE) were shown in workers with LE compared to those without LE. Also, the range of wrist extension was significantly lower in workers with LE than in those without LE.

CONCLUSIONS

Quantifying the ratio of muscle activity with altered kinematics of wrist extension may help researchers to understand why overuse of ECR is occurring and explain LE development in automobile assembly line workers.

The "hierarchical" Scratch Collapse Test for identifying multilevel ulnar nerve compression

BACKGROUND

The Scratch Collapse Test (SCT) is used to assist in the clinical evaluation of patients with ulnar nerve compression. The purpose of this study is to introduce the hierarchical SCT as a physical examination tool for identifying multilevel nerve compression in patients with cubital tunnel syndrome.

METHODS

A prospective cohort study (2010-2011) was conducted of patients referred with primary cubital tunnel syndrome. Five ulnar nerve compression sites were evaluated with the SCT. Each site generating a positive SCT was sequentially "frozen out" with a topical anesthetic to allow determination of both primary and secondary ulnar nerve entrapment points. The order or "hierarchy" of compression sites was recorded.

RESULTS

Twenty-five patients (mean age 49.6 ± 12.3 years; 64 % female) were eligible for inclusion. The primary entrapment point was identified as Osborne's band in 80 % and the cubital tunnel retinaculum in 20 % of patients. Secondary entrapment points were also identified in the following order in all patients: (1) volar antebrachial fascia, (2) Guyon's canal, and (3) arcade of Struthers.

CONCLUSION

The SCT is useful in localizing the site of primary compression of the ulnar nerve in patients with cubital tunnel syndrome. It is also sensitive enough to detect secondary compression points when primary sites are sequentially frozen out with a topical anesthetic, termed the hierarchical SCT. The findings of the hierarchical SCT are in keeping with the double crush hypothesis described by Upton and McComas in 1973 and the hypothesis of multilevel nerve compression proposed by Mackinnon and Novak in 1994.

Social impact of peripheral nerve injuries

BACKGROUND

Disorders involving the peripheral nervous system can have devastating impacts on patients' daily functions and routines. There is a lack of consideration of the impact of injury on social/emotional well-being and function.

METHODS

We performed a retrospective database and chart review of adult patients presenting between 2010 and 2012 with peripheral nerve compression, brachial plexus injury, thoracic outlet syndrome (TOS), or neuromas. At the initial assessment, patients completed a questionnaire used to obtain demographic and psychosocial variable data including the (1) average level of pain over the last month, (2) self-perceived depression, (3) how much pain impacts quality of life (QoL), (4) current level of stress, and (5) ability to cope with stress. Statistical analyses were used to assess the differences between the dependent variables and diagnostic and demographic groups.

RESULTS

This study included 490 patients (mean age 50 ± 15 years); the most common diagnosis was single nerve compression (n = 171). Impact on QoL was significantly greater in patients with TOS, cutaneous peroneal compressions, and neuroma versus single site nerve compressions. Average pain, impact on QoL, and stress at home were significantly higher in females versus males. Impact on QoL was correlated with average pain, depression, stress at home, and ability to cope with stress at home.

CONCLUSIONS

Our study demonstrates that patients with single site nerve compression neuropathies experience fewer negative psychosocial effects compared to patients with more proximal upper extremity peripheral nerve disorders and neuromas. The impact on QoL was strongly correlated with pain and depression, where patients with neuromas and painful peroneal nerve entrapments reported greater detriments to QoL.

Chiropractic management of a patient with ulnar nerve compression symptoms: a case report

OBJECTIVE

The purpose of this case report is to describe chiropractic management of a patient with arm and hand numbness and who was suspected to have ulnar nerve compression.

CLINICAL FEATURES

A 41-year-old woman presented with hand weakness and numbness along the medial aspect of her right forearm and the 3 most medial fingers. The onset of symptoms presented suddenly, 3 weeks prior, when she woke up in the morning and assumed she had "slept wrong." The patient's posture showed protracted shoulders and moderate forward head carriage. Orthopedic assessment revealed symptomatic right elevated arm stress test, grip strength asymmetry, and a Tinel sign at the right cubital tunnel.

INTERVENTION AND OUTCOME

The patient was treated using chiropractic care, which consisted of manipulative therapy, myofascial therapy, and elastic therapeutic taping. Active home care included performing postural exercises and education about workstation ergonomics. She demonstrated immediate subjective improvement of her numbness and weakness after the first treatment. Over a series of 11 treatments, her symptoms resolved completely; and she was able to perform work tasks without dysfunction.

CONCLUSION

Chiropractic treatment consisting of manipulation, soft tissue mobilizations, exercise, and education of workstation ergonomics appeared to reduce the symptoms of ulnar nerve compression symptoms for this patient.

Thoracic outlet syndrome: a 50-year experience at Baylor University Medical Center

During the past 5 decades, the recognition and management of thoracic outlet syndrome (TOS) have evolved. This article elucidates these changes and improvements in the diagnosis and management of TOS at Baylor University Medical Center. The most remarkable change over the past 50 years is the use of nerve conduction velocity to diagnose and monitor patients with nerve compression. Recognition that procedures such as breast implantation and median sternotomy may produce TOS has been revealing. Prompt thrombolysis followed by surgical venous decompression for Paget-Schroetter syndrome has markedly improved results compared with the conservative anticoagulation approach; thrombolysis and prompt first rib resection is the optimal treatment for most patients with Paget-Schroetter syndrome. Complete first rib extirpation at the initial procedure markedly reduces the incidence of recurrent neurologic symptoms or the need for a second procedure. Chest pain or pseudoangina can be caused by TOS. Dorsal sympathectomy is helpful for patients with sympathetic maintained pain syndrome or causalgia and patients with recurrent TOS symptoms who need a second procedure.

Thoracic outlet syndrome: definition, aetiological factors, diagnosis, management and occupational impact

INTRODUCTION

Thoracic outlet syndrome is a controversial cause of neck and shoulder pain due to complex mechanisms involving muscular dysfunction and nerve compression. Although management of thoracic outlet syndrome must be based on a multidisciplinary approach, physicians and occupational therapist should be familiar with the principles of diagnosis and treatment.

METHOD, RESULTS AND CONCLUSION

The purpose of this article is to review the definitions, diagnosis and management of this syndrome. A particular emphasis was described on the links between the workplace and the individual in the pathogenesis, prevalence in the workforce and the course of this disease.

Cluster analysis of symptoms among patients with upper extremity musculoskeletal disorders

INTRODUCTION

Some musculoskeletal disorders of the upper extremity are not readily classified. The study objective was to determine if there were symptom patterns in self-identified repetitive strain injury (RSI) patients.

METHODS

Members (n = 700) of the Dutch RSI Patients Association filled out a detailed symptom questionnaire. Factor analysis followed by cluster analysis grouped correlated symptoms.

RESULTS

Eight clusters, based largely on symptom severity and quality were formulated. All but one cluster showed diffuse symptoms; the exception was characterized by bilateral symptoms of stiffness and aching pain in the shoulder/neck.

CONCLUSIONS

Case definitions which localize upper extremity musculoskeletal disorders to a specific anatomical area may be incomplete. Future clustering studies should rely on both signs and symptoms. Data could be collected from health care providers prospectively to determine the possible prognostic value of the identified clusters with respect to natural history, chronicity, and return to work.

The effect of forearm posture on wrist flexion in computer workers with chronic upper extremity musculoskeletal disorders

Background

Occupational computer use has been associated with upper extremity musculoskeletal disorders (UEMSDs), but the etiology and pathophysiology of some of these disorders are poorly understood. Various theories attribute the symptoms to biomechanical and/or psychosocial stressors. The results of several clinical studies suggest that elevated antagonist muscle tension may be a biomechanical stress factor. Affected computer users often exhibit limited wrist range of motion, particularly wrist flexion, which has been attributed to increased extensor muscle tension, rather than to pain symptoms. Recreational or domestic activities requiring extremes of wrist flexion may produce injurious stress on the wrist joint and muscles, the symptoms of which are then exacerbated by computer use. As these activities may involve a variety of forearm postures, we examined whether changes in forearm posture have an effect on pain reports during wrist flexion, or whether pain would have a limiting effect on flexion angle.

Methods

We measured maximum active wrist flexion using a goniometer with the forearm supported in the prone, neutral, and supine postures. Data was obtained from 5 subjects with UEMSDs attributed to computer use and from 13 control subjects.

Results

The UEMSD group exhibited significantly restricted wrist flexion compared to the control group in both wrists at all forearm postures with the exception of the non-dominant wrist with the forearm prone. In both groups, maximum active wrist flexion decreased at the supine forearm posture compared to the prone posture. No UEMSD subjects reported an increase in pain symptoms during testing.

Conclusion

The UEMSD group exhibited reduced wrist flexion compared to controls that did not appear to be pain related. A supine forearm posture reduced wrist flexion in both groups, but the reduction was approximately 100% greater in the UEMSD group. The effect of a supine forearm posture on wrist flexion is consistent with known biomechanical changes in the distal extensor carpi ulnaris tendon that occur with forearm supination. We infer from these results that wrist extensor muscle passive tension may be elevated in UEMSD subjects compared to controls, particularly in the extensor carpi ulnaris muscle. Measuring wrist flexion at the supine forearm posture may highlight flexion restrictions that are not otherwise apparent.

Upper limb muscle imbalance in tennis elbow: a functional and electromyographic assessment

The purpose of this study was to investigate strength, fatigability, and activity of upper limb musculature to elucidate the role of muscular imbalance in the pathophysiology of tennis elbow. Sixteen patients clinically diagnosed with tennis elbow, recruited from a university hospital upper limb orthopedic clinic, were compared with 16 control subjects with no history of upper limb musculoskeletal problem, recruited from university students and staff. Muscle strength was measured for grip, metacarpophalangeal, wrist, and shoulder on both sides. Electromyographic activity (RMS amplitude) and fatigue characteristics (median frequency slope) of five forearm and two shoulder muscles were measured during isometric contraction at 50% maximum voluntary contraction. All strength measurements showed dominance difference in C, but none in TE. In tennis elbow compared to controls, hand/wrist and shoulder strength and extensor carpi radialis (ECR) activity were reduced (p < 0.05), while fatigue was normal. A global upper limb weakness exists in tennis elbow. This may be due to disuse and deconditioning syndrome caused by fear avoidance, and needs to be addressed in prevention and treatment. Activation imbalance among forearm muscles (reduced extensor carpi radialis activity) in tennis elbow, probably due to protective pain-related inhibition, could lead to a widespread upper limb muscle imbalance.

Management of radial tunnel syndrome: a therapist's clinical perspective

Current best evidence for the conservative management of radial tunnel syndrome (RTS) consists primarily of expert opinion and inferences taken from studies on other nerve compressions and related syndromes. There are limited data reported in the literature of this particular disorder. This article reviews literature on modalities, therapeutic exercise, ergonomic interventions, and cortical reorganization, and how they may be considered for intervention with RTS. The author's preferred method of treatment, as based on theoretical constructs, for RTS is presented. Definitive evidence in the literature to support the conservative interventions suggested is lacking. Suggestions for clinical management and study are included in this therapist's clinical perspective.

Evaluation of nerve injury and nerve compression in the upper quadrant

Evaluation of the patient with nerve compression and/or nerve injury should include a complete motor and sensory evaluation to establish the level and degree of injury and/or compression. No one test has been accepted as the standard procedure for the evaluation of sensibility. The various sensory tests available for patient assessment will yield different information regarding the integrity of the quickly and slowly adapting sensory receptors. Tests such as provocative maneuvers and sensory thresholds (cutaneous and vibration) will be more sensitive in the evaluation of patients with nerve compression, and other discriminatory measures will yield better functional information in patients with nerve injury.

Repetitive motion in perception of tactile sensation in the fingers of string players

Little is known about the mechanisms that underlie the pathophysiology involved in the development of cumulative trauma disorders. Musicians, specifically string players, may be a useful model to examine the cumulative effects of repetitive motion given the highly attended movements of their left hands and the stereotypical grasp of their right hands. Musculoskeletal disorders related to playing are experienced by 39% to 87% of musicians, making musicians a potentially good model for the study of factors involved in development of cumulative trauma disorders. Sensory thresholds for two-point discrimination and light touch were measured in all phalanges of each digit, of each hand. Comparisons were made within and between a control group of 10 nonmusicians who did not engage in repetitive motion and 10 healthy musicians who did. There were 5 violinists, 2 violists, and 3 cellists. The Non-musician group perceived two-points and light touch at significantly lower thresholds in the proximal phalanges of the left hand than the right hand. Significant differences were not present between right and left hands for the means of distal, middle, and proximal phalanges of the Musician group. This lack of significant difference may be due to higher sensory thresholds associated with repetitive use of the left hand of the musicians.

Glutamate and prostaglandin E2 in the trapezius muscle of female subjects with chronic muscle pain and controls determined by microdialysis

Much is still unknown concerning the mechanisms underlying the development of chronic muscle pain. The presence and magnitude of inflammatory substances and neurotransmitters in chronic painful conditions is not clear. The aims of the present study were to determine, with the use of microdialysis, the interstitial concentrations and the equilibration times for PGE2 and glutamate in the trapezius muscles of nine female subjects with chronic muscle pain, and nine pain-free age-matched controls. A microdialysis probe was implanted in the upper part of the trapezius muscle and perfused with Ringer-acetate solution at a flow rate of 0.3 microL/min. Samples were obtained every 30 min, during a 4-h rest period. At equilibration, the mean concentrations (+/-SE) of PGE2 were 0.71 (+/-0.11) ng/mL for the pain-group and 0.97 (+/-0.35) ng/mL for the controls. For glutamate the mean concentrations for the pain-group were 66.3 (+/-13.3) micromol/L and 60.6 (+/-22.9) micromol/L for the controls. For the pain group and the control group, respectively, equilibration for PGE2 was reached at 180 and 150 min, and for glutamate at 150 and 120 min. The present study showed no differences between groups in the concentrations of PGE2 and glutamate in the trapezius muscle. Further, it revealed that when using the slow-flow method, a period of at least 2.0-2.5 h is needed, after probe insertion, to reach steady state for glutamate and PGE2.

The relationship between symptoms and electrophysiological detected compression of the median nerve at the wrist

OBJECTIVE

The aim of this study was to evaluate the relationship between carpal tunnel syndrome symptoms and compression of the median nerve at the wrist in symptomatic patients.

METHODS

A total of 250 patients were selected among those referred for electrodiagnostic evaluation with complaints involving hand or wrist. Primary and secondary symptoms were extracted from the answers to the instrument proposed by Levine et al. [J Bone Joint Surg Am 1993;75:1585]. The association of symptoms and the presence of compression of the median nerve at the wrist were ascertained through a multiple logistic regression test.

RESULTS

Secondary symptoms (pain and weakness) were inversely associated with the presence of median nerve compression. Furthermore, primary symptoms (paresthesia, disability and nocturnal symptom) occurred similarly in patients with and without electrophysiologic findings of median nerve compression at the wrist.

Upper extremity work-related musculoskeletal disorders: a treatment perspective

Numerous terms, including repetitive-stress injuries and cumulative-trauma disorders, have been used to describe what is now commonly termed work-related musculoskeletal disorders. The etiology of work-related musculoskeletal disorders is multifactorial and includes physical, individual, and psychosocial factors that contribute to the presenting symptoms. Prolonged positioning away from the ideal posture will affect neural and other soft tissues in the upper extremity. Abnormal postures and positions may result in chronic nerve compression or may shorten muscles and, if the muscle crosses over a nerve, compression may occur. These postures may also contribute to muscle imbalance. A thorough clinical evaluation is necessary to identify all sites of nerve compression, muscle imbalance, and factors affecting patient symptoms so that appropriate intervention can be instituted. Management must include patient education, postural correction, and a specific physical therapy program to address the multiple levels of nerve compression and cervicoscapular muscle imbalance. In addition to physical therapy intervention, behavioral modification at home and at work may be necessary for successful management.

Work-related musculoskeletal disorders: the epidemiologic evidence and the debate

The debate about work-relatedness of musculoskeletal disorders (MSDs) reflects both confusion about epidemiologic principles and gaps in the scientific literature. The physical ergonomic features of work frequently cited as risk factors for MSDs include rapid work pace and repetitive motion, forceful exertions, non-neutral body postures, and vibration. However, some still dispute the importance of these factors, especially relative to non-occupational causes. This paper addresses the controversy with reference to a major report recently commissioned by the US Congress from the National Research Council (NRC) and Institute of Medicine (IOM) (2001). The available epidemiologic evidence is substantial, but will benefit from more longitudinal data to better evaluate gaps in knowledge concerning latency of effect, natural history, prognosis, and potential for selection bias in the form of the healthy worker effect. While objective measures may be especially useful in establishing a more secure diagnosis, subjective measures better capture patient impact. Examination techniques still do not exist that can serve as a "gold standard" for many of the symptoms that are commonly reported in workplace studies. Finally, exposure assessment has too often been limited to crude indicators, such as job title. Worker self-report, investigator observation, and direct measurement each add to understanding but the lack of standardized exposure metrics limits ability to compare findings among studies. Despite these challenges, the epidemiologic literature on work-related MSDs-in combination with extensive laboratory evidence of pathomechanisms related to work stressors-is convincing to most. The NRC/IOM report concluded, and other reviewers internationally have concurred, that the etiologic importance of occupational ergonomic stressors for the occurrence of MSDs of the low back and upper extremities has been demonstrated.

Evaluation of the nerve-injured patient

The evaluation of patients with nerve injury or nerve compression requires an accurate history and subjective report to determine the tests that are the most useful in providing the essential information. Motor and sensory evaluation is necessary inglobal mixed-nerve injuries, but in cases of nerve compression, tests of provocation give more accurate information for detecting the site of nerve compression. There is no gold standard test in the evaluation of patients with nerve injury or compression; therefore, a battery of valid and reliable sensory and motor tests provides the most complete information to formulate a treatment plan.

Thoracic outlet syndrome

Success in conservative management depends upon an accurate assessment and development of a treatment plan relative to the irritability of the patient's condition. Postural correction and avoidance of irritating positions must begin early in the rehabilitation phase to retrain the patient in symptom-reducing postures. Treatment addressing only the neurovascular structures may produce temporary relief of symptoms, but postural correction cannot be maintained without correction of the associated muscle imbalance in the cervicoscapular region. Long-term success of conservative management depends on patient compliance to a home exercise program and behavior modification at home and at work. Surgical decompression should be reserved for patients who fail to improve with conservative management.

[Translation and validation of an instrument for evaluation of severity of symptoms and the functional status in carpal tunnel syndrome]

The objective of the present study was to translate, to do cultural equivalence and validation of the Levine et al. (1993) or Boston Carpal Tunnel Questionnaire (BCTQ) to Portuguese. The BCTQ application to patients, selected by the question "What was the reason that brought you to look for a physician and that led him to ask this examination?" showed very good reproducibility. The validity was measured through the comparison of the severity symptoms scores (SSS) and the functional status scores (FSS) with the results of grip forces, Minnesota, two point discrimination, Semmes-Weinstein filaments perception and sensory conduction at the median nerve. The internal consistency was evaluated through Chronbach's alpha coefficient comparing the SSS and the FSS. The measuring properties were evaluated through paired t-test between pre and pos-surgical scores. Reproducibility, internal consistency, validation and measuring properties of the translated BCTQ were similar to those found by Levine et al. with the original version.

Abordagem clínica e psicossocial das Lesões por Esforços Repetitivos LER / DORT

Revisão bibliográfica, com abordagem clínica, psicológica e social dos problemas causados pelas Lesões por Esforços Repetitivos - LER, hoje melhor definidas como Distúrbio Osteomusculares Relacionados ao Trabalho - DORT. São discutidos neste texto, a sinonímia utilizada em toda a literatura pesquisada, alguns dados epidemiológicos, em nível mundial e nacional, quanto à distribuição da doença segundo algumas varáveis tais como: sexo, idade, tipo de atividade, tempo e localização anatômica das queixas, afastamento do trabalho etc. Além desses pontos, são enfocados estudos sobre fatores etiológicos e fisiopatológicos das LER / DORT. Por fim, buscou-se uma correlação entre todos estes fatores anteriormente citados e o psicossocial, pontuando os elementos que influenciam diretamente no aparecimento e/ou manutenção desta enfermidade multifatorial, salientado a importância da organização do trabalho na sua prevenção.

Pathomechanisms of work-related musculoskeletal disorders: conceptual issues

Work-related musculoskeletal disorders (WRMSDs) by definition are a subset of musculoskeletal disorders (MSDs) that arise out of occupational exposures. While traditional exposure assessment techniques have proved to be successful in identifying ergonomic exposures that are epidemiologically linked to these disorders, some are troubled by the lack of one-to-one correspondence between specific occupational exposure profiles and specific MSDs. In the absence of more sophisticated hypotheses that might explain the occurrence of WRMSDs in a variety of exposure patterns, the aetiologic relationships may (again) be called into question. Another unanswered question is whether specific types of WRMSDs have qualitatively different exposure-response relationships. A clearer understanding of the underlying pathomechanisms associated with specific WRMSDs could help future researchers better determine how and when various occupational exposure profiles become pathogenic. Such knowledge could also be used to design exposure assessment tools to capture exposure information more relevant to the risk of WRMSDs. The main goals of this paper are to summarize several recently described pathomechanisms, most of which have been discussed primarily in clinical and experimental literature that might not be widely read by occupational health scientists. Suggestions are made as to how future research could evaluate whether these phenomena are relevant to the effects of physical exposures and the underlying disease processes of common WRMSDs.

Multilevel nerve compression and muscle imbalance in work-related neuromuscular disorders

BACKGROUND

Work-related upper limb disorders have come under increasing scrutiny and become a frustrating problem.

METHODS

A unifying hypothesis to explain the multiplicity of symptoms with work related neuromuscular disorders is outlined. This multifactorial problem includes physical, individual, and psychosocial factors. Abnormal postures and positions may compress nerves or may alter muscle length resulting in secondary compressive forces on nerves or in muscle imbalances. Evaluation should identify all nerve compression levels and muscle imbalance in the arm and cervicoscapular region. Management must include patient education, postural correction, and an exercise program to address the multiple nerve compression levels and muscle imbalance.

RESULTS AND CONCLUSIONS

The etiology of work related neuromusculoskeletal disorders is multifactorial and successful management must address all contributing factors. Appropriate conservative management will relieve symptoms in most patients. Surgery should be reserved for those few patients with evidence of a specific diagnosis who have failed conservative management.

Multiple Entrapment Neuropathy in the Upper Extremity

Multiple entrapment neuropathy is compression of more than two nerves in the same extremity. In this case series, 169 patients (208 upper extremities) with this condition were identified, and 124 patients (138 upper extremities) had surgical decompression after an ineffective course of conservative treatment. There were 31 men and 93 women. Average age was 41 years (range 20-87 years). Follow-up averaged 23 months (range 12 to 60 months). Our rating system included patients' self-assessment of overall symptom improvement and return to activity and a physician assessment of strength (grip and pinch) and sensibility (recovery of two-point discrimination). A total of 92 patients (67%) achieved good to excellent results. The clinical features of multiple entrapment neuropathy in our series were presented with a variety of nerve compression syndromes and with a high incidence of regional musculotendinous syndromes. In our surgical treatment, we emphasise simultaneous release of all possible compression sites with a minimally invasive endoscopic approach to achieve better results.

Wrist posture during computer pointing device use

OBJECTIVE

This research examines individual differences in the wrist postures adopted during the use of two pointing devices (mouse and trackball).

DESIGN

A multiple case study of twelve participants was employed.

BACKGROUND

The use of pointing devices may lead to musculoskeletal discomfort and injury as a consequence of prolonged exposure to postures involving wrist extension and ulnar deviation.

METHODS

Wrist flexion/extension and radial/ulnar deviation was measured while twelve participants completed two standardised tasks involving horizontal and vertical cursor movements respectively.

RESULTS

Exposure to extreme ulnar deviation and wrist extension was observed in the use of computer mouse and trackball. The trackball involved decreased ulnar deviation and increased wrist extension, however considerable individual differences were observed.

CONCLUSIONS

Some users may be placed at risk of injury by prolonged exposure to the use of such devices, while others may not. A trackball may reduce the exposure to extreme ulnar deviation, but in some cases, a trackball may increase exposure to extreme wrist extension.

Carpal tunnel syndrome: clinical outcome after low-level laser acupuncture, microamps transcutaneous electrical nerve stimulation, and other alternative therapies--an open protocol study

OBJECTIVE

Outcome for carpal tunnel syndrome (CTS) patients (who previously failed standard medical/surgical treatments) treated primarily with a painless, noninvasive technique utilizing red-beam, low-level laser acupuncture and microamps transcutaneous electrical nerve stimulation (TENS) on the affected hand; secondarily, with other alternative therapies.

DESIGN

Open treatment protocol, patients diagnosed with CTS by their physicians.

SETTING

Treatments performed by licensed acupuncturist in a private practice office.

SUBJECTS

Total of 36 hands (from 22 women, 9 men), ages 24-84 years, median pain duration, 24 months. Fourteen hands failed 1-2 surgical release procedures. INTERVENTION/TREATMENT: Primary treatment: red-beam, 670 nm, continuous wave, 5 mW, diode laser pointer (1-7 J per point), and microamps TENS (< 900 microA) on affected hands. Secondary treatment: infrared low-level laser (904 nm, pulsed, 10 W) and/or needle acupuncture on deeper acupuncture points; Chinese herbal medicine formulas and supplements, on case-by-case basis. Three treatments per week, 4-5 weeks.

OUTCOME MEASURES

Pre- and posttreatment Melzack pain scores; profession and employment status recorded.

RESULTS

Posttreatment, pain significantly reduced (p < .0001), and 33 of 36 hands (91.6%) no pain, or pain reduced by more than 50%. The 14 hands that failed surgical release, successfully treated. Patients remained employed, if not retired. Follow-up after 1-2 years with cases less than age 60, only 2 of 23 hands (8.3%) pain returned, but successfully re-treated within a few weeks.

CONCLUSIONS

Possible mechanisms for effectiveness include increased adenosine triphosphate (ATP) on cellular level, decreased inflammation, temporary increase in serotonin. There are potential cost-savings with this treatment (current estimated cost per case, $12,000; this treatment, $1,000). Safe when applied by licensed acupuncturist trained in laser acupuncture; supplemental home treatments may be performed by patient under supervision of acupuncturist.

Overuse tendinitis of the intrinsic muscles

Repetitive strain injuries are currently the leading cause of occupational illnesses. This report describes seven patients who presented with the sole symptom of hand pain and subsequently were diagnosed with intrinsic tendinitis. Six of the 7 patients were given injections of a local anesthetic and steroid solution into the region of the lumbrical tunnels for both diagnostic and therapeutic purposes. All 6 patients had immediate short-term resolution of their symptoms in the office, thereby confirming the diagnosis. Complete resolution of symptoms after both the injection and other treatment interventions occurred in 4 patients, and partial resolution of symptoms occurred in the remaining two patients. Follow-up ranged from 3 to 20 months for 6 patients, and the seventh patient was lost to follow-up. The clinical presentation, diagnostic work-up, and treatment of intrinsic tendinitis are described.

Repetitive use and static postures: a source of nerve compression and pain

Nerve compression or musculoskeletal diagnoses require consideration of both the repetitive movements and static postures that may be contributing to the problem. Certain postures and positions assumed at home, at work, and during sleep will have three major influences: (1) directly increasing pressure on nerves at entrapment sites; (2) placing muscles in shortened positions so that adaptive muscle shortening may then secondarily compress nerves; and (3) placing some muscles in elongated and weakened positions, resulting in other muscles being over-used, thus creating the cycle of muscle imbalance. Successful management of the patient with upper extremity pain, paresthesia, and numbness should begin with initial identification of all sites that are contributing to the presenting symptoms. Treatment must then be directed toward the sources of nerve compression and musculoskeletal dysfunction. Upper quadrant symptomatology can be alleviated with an appropriate therapy program, even in the patient with chronic symptoms, but only with patient education, compliance with an exercise program, and behavioral modification at home, work, and during sleep.

Relation of preoperative nerve-conduction values to outcome in workers with surgically treated carpal tunnel syndrome

Ninety-three workers having undergone carpal tunnel decompression were assessed 16 to 100 months after surgery. The results of outcomes pertaining to symptoms of numbness, nocturnal awakening, and pain as well as job status were compared to the patients' preoperative nerve conduction study findings. Significant differences in preoperative nerve-conduction values (NCVs) were found between groups reporting poor results and those reporting good results. These differences were such that those reporting poor results had more normal NCVs. Those reporting job changes because of carpal tunnel syndrome also had more normal preoperative nerve-conduction results. Data indicate that those with terminal latencies 1 ms greater than the testing facility normal value or with sensory conduction velocity 10 ms less than the facility norm were more likely to benefit from surgery. This study suggests the need for caution when considering carpal tunnel surgery in workers with normal or near normal nerve-conduction results.