Validation of a surveillance case definition of carpal tunnel syndrome

Electrodiagnostic signs of carpal tunnel syndrome in ocular pseudoexfoliation syndrome

PURPOSE

To assess the occurrence and severity of electrodiagnostic signs of carpal tunnel syndrome (ED-CTS) in patients with ocular pseudoexfoliation (PEX) and compare them with normal subjects.

METHOD

A cross-sectional study with comparison group was designed and 60 patients with PEX were recruited from May 2019 to February 2021, and the findings were compared with 59 healthy subjects. All patients underwent complete ophthalmologic examination and nerve conduction velocity test at the median nerve was used to assess the occurrence and severity of ED-CTS in both hands.

RESULTS

The mean age of participants was 59.8 ± 4.5 years. Occurrence of ED-CTS was 38.3% in PEX patients and 20.3% in control subjects (P = 0.025). There was also a significant difference in the severityand presence of asymptomatic CTS (P < 0.05). Adjusting other variables, including; age and sex, having severe ED-CTS showed a 3.07fold higher chance in the PEX group (P = 0.005).

CONCLUSION

According to our finding, it seems there is a direct association between PEX and the occurrence, as well as severity of ED-CTS.

The effect of median nerve mobilization on two point discrimination

[Purpose] Two-point discrimination (TPD) is expressed as the minimum distance at which two mechanical stimuli applied simultaneously to the skin can be perceived as two separate points. The aim of this study was to investigate the effect of median nerve mobilization on TPD in healthy adults. [Participants and Methods] This study included 120 healthy adults. Participants were randomized according to their gender into the Neural Mobilization Group (NMG) and Control Group (CG). Demographic data of the participants (gender, age, height, weight, BMI, smoking) were recorded and TPD measurement was performed with baseline aesthesiometer on the palm with distal phalanges of the thumb, index and middle finger on the right-left hand. After the baseline TPD test, participants in the NMG performed Median Nerve Mobilization for 14 days. Measurements were taken before and after training. [Results] A statistically significant difference was found in all other measurements in both groups, except for the right and left palm TPD measurements in the control group. [Conclusion] It is thought that it would be beneficial to investigate the healing effects of the neural mobilization applications, which include all parts of the nerve line in disease conditions.

Accuracy of diagnostic clinical tests and questionnaires in screening for carpal tunnel syndrome among workers- A systematic review

OBJECTIVE

To synthesize and appraise the evidence on the diagnostic accuracy of the clinical examination tests and questionnaires for screening carpal tunnel syndrome (CTS) among workers.

DESIGN

Systematic review of diagnostic test accuracy METHODS: Electronic search of 3 online databases (CINAHL, Embase, Medline) was done on August 31, 2020. Studies reporting the diagnostic accuracy of clinical examination tests in workers, compared to a reference standard test, were included. Diagnostic accuracy measures such as sensitivity (Sn) and specificity (Sp) were extracted and reported for different clinical examination tests. The risk of bias and applicability concerns were rated using the Quality Assessment of Diagnostic Accuracy Studies-2 tool by 2 independent reviewers. Diagnostic tests accuracy extension of the PRISMA guidelines were followed.

RESULTS

Twelve studies reporting on the diagnostic accuracy of the clinical examination tests for workers suspected of CTS were included. Fourteen different clinical examination tests were evaluated in the studies, including sensorimotor, provocative maneuvers, questionnaires, and hand symptom diagrams (HSD). Ten of the included studies had an either unclear or high risk of bias. The most accurate tests to diagnose CTS in workers were the Katz HSD (with Sn ranging from 38%-93%, and Sp ranging from 25%-89%) and Kamath and Stothard questionnaire (Sn and Sp = 100%). Combination of Katz HSD with either the Phalen's maneuver or the Tinel's sign resulted in excellent Sp (83% and 89%, respectively).

CONCLUSIONS

Low to moderate quality evidence indicates variability in individual clinical examination tests used to screen for CTS in workers. Diagnostic self-report tools consisting of hand diagrams and/or diagnostic questions provide low burden and high accuracy. Still, they require more rigorous investigation about their value alone or in combination with clinical assessment tests.

The Value of the History in the Diagnosis of Carpal Tunnel Syndrome

Details of the clinical history were elicited by questionnaire from 8,223 patients with suspected carpal tunnel syndrome and compared with the neurophysiological findings. Distribution of symptoms to the radial part of the hand and nocturnal exacerbation of symptoms showed the strongest individual correlations with positive nerve conduction studies. The regression model derived from the complete questionnaire achieved an overall sensitivity of 79% and specificity of 55% for the diagnosis of carpal tunnel syndrome when compared with the nerve conduction study results as a gold standard. A simple regression model for evaluating the history compares favourably with widely used clinical signs in its ability to predict the findings of nerve conduction studies.

'Cuff Sign' a new maneuver for decision-making in patients with carpal tunnel syndrome

BACKGROUND

Carpal tunnel syndrome (CTS) is the most common entrapment neuropathy that results from compression of the median nerve within the carpal tunnel. In most patients, the diagnosis can be proposed based on patient history and clinical symptoms, with physical findings being attributed only in more severely affected patients. The purpose of this study is to introduce a reliable and accurate method for the proper selection of patients with mild carpal tunnel syndrome (CTS), for surgery.

MATERIALS AND METHODS

Electerodiagnostic studies are performed before and after placement of the cuff of the sphygmomanometer at the arm (Cuff sign), at a mean arterial pressure, for three minutes. Thirty symptomatic patients with mild findings on electrodiagnostic studies and 49 asymptomatic control hands have been included.

RESULTS

Fifteen patients reported good pain relief on the first postoperative day (50%), which increased to 21 on the fouteenth postoperative day (70%). The sensory latency changes were significantly higher in the pain relief group, both on the first and fourteenth postoperative days.

CONCLUSION

Considering the fact that cooperation of the patients is not necessary and the double effects of direct pressure and ischemia over the proximal parts of the median nerve leads to prolonged latencies, this test is a useful method for decision-making in patients with severe symptoms of CTS, despite the mild electrodiagnostic findings.

Feasibility of a novel functional sensibility test as an assisted examination for determining precision pinch performance in patients with carpal tunnel syndrome

To understand the feasibility of a novel functional sensibility test for determining precision pinch performance in patients with carpal tunnel syndrome, this study investigates the validity, sensitivity and specificity of functional sensibility derived from a pinch-holding-up activity (PHUA) test. Participants include 70 clinically defined carpal tunnel syndrome (CTS) patients with 119 involved hands and 70 age- and gender-matched controls. To examine the discriminating ability of the functional sensibility test, the differences in the ability of pinch force adjustments to the inertial load of handling object between CTS and control subjects are analyzed. The results of functional sensibility are correlated with the severity of CTS to establish concurrent validity. The receiver operating characteristic (ROC) curve is constructed to demonstrate the accuracy of the proposed test. The functional sensibility score significantly discriminates the patients and control groups (respectively, 12.94±1.72 vs. 11.51±1.15N in peak pinch force (FP_Peak), p<0.001; 2.92±0.41 vs. 2.52±0.24 in force ratio, p<0.001) and is moderately correlated (r = 0.42–0.54, p<0.001) with the results of traditional sensibility tests (touch-pressure threshold and two-point discrimination test). In addition, there is a statistical difference in the results of functional sensibility (p<0.001) among the subgroups of CTS severity based on electrophysiological study. The sensitivity and specificity are 0.79 and 0.76, respectively, for the functional sensibility test. The areas under the ROC curve are 0.85 and 0.80 for the force ratio and FP_Peak, respectively. In conclusion, the functional sensibility test could be feasibly used as a clinical tool for determining both the sensibility and precision pinch performance of hands for the patients with CTS.

Ultrasound-guided carpal tunnel release using the manos CTR system

PURPOSE

Ultrasound (US) has been used in the management of carpal tunnel syndrome since the 1980s. The first report of US-guided carpal tunnel release (CTR) was published in 1997, with cadaver and clinical reports confirming the safe navigation of surgical tools with US for division of the transverse carpal ligament. The MANOS CTR device was recently reported as a minimally invasive tool for CTR, and may be well suited for use with US guidance.

PATIENTS AND METHODS

The authors report three cases of US-guided CTR using the MANOS CTR device. The MANOS device was inserted in a blunt configuration into the safe zone, and the cutting surface was deployed with a thumb-activated trigger that simultaneously ejected a sharp through the palm. The transverse carpal ligament was divided safely and confirmed with US.

RESULTS

US allowed for clear identification of the median nerve, safe zones, transverse carpal ligament, and the MANOS CTR device in relation to all pertinent structures of the carpal tunnel. Complete division of the transverse carpal ligament was confirmed in all three cases. There were no median nerve, vessel, tendon injuries, or chronic regional pain syndrome in any of the three cases.

CONCLUSIONS

US-guided CTR with the MANOS CTR device appears to be a safe technique and successful in confirming complete release.

Comparison of research case definitions for carpal tunnel syndrome

OBJECTIVE

The aim of this study was to assess agreement between different case definitions of carpal tunnel syndrome (CTS) for epidemiological studies.

METHODS

We performed a literature search for papers suggesting case definitions for use in epidemiological studies of CTS. Using data elements based on symptom questionnaires, hand diagrams, physical examinations, and nerve conduction studies collected from 1107 newly-hired workers, each subject in the study was classified according to each of the case definitions selected from the literature. We compared each case definition to every other case definition, using the Kappa statistic to measure pair-wise agreement on whether each subject met the case definition.

RESULTS

We found six unique papers in a 20-year period suggesting a case definition of CTS for use in population-based studies. We extracted seven case definitions. Definitions included different parameters: (i) symptoms only, (ii) symptoms and physical examination, (iii) symptoms and either physical examination or median nerve conduction study, and (iv) symptoms and nerve conduction study. When applied to our study population, the prevalence of CTS using different case definitions ranged from 2.5-11.0%. The percentage of misclassification was between 1-10%, with generally acceptable levels of agreement (kappa values ranged from 0.30-0.85).

CONCLUSIONS

Different case definitions resulted in widely varying prevalences of CTS. Agreement between case definitions was generally good, particularly between those that required very specific symptoms or the combination of symptoms and physical examination or nerve conduction. The agreement observed between different case definitions suggests that the results can be compared across different research studies of risk factors for CTS.

The burden and determinants of neck pain in the general population: results of the Bone and Joint Decade 2000-2010 Task Force on Neck Pain and Its Associated Disorders

STUDY DESIGN

Best evidence synthesis.

OBJECTIVE

To undertake a best evidence synthesis of the published evidence on the burden and determinants of neck pain and its associated disorders in the general population.

SUMMARY OF BACKGROUND DATA

The evidence on burden and determinants of neck has not previously been summarized.

METHODS

The Bone and Joint Decade 2000-2010 Task Force on Neck Pain and Its Associated Disorders performed a systematic search and critical review of literature published between 1980 and 2006 to assemble the best evidence on neck pain. Studies meeting criteria for scientific validity were included in a best evidence synthesis.

RESULTS

We identified 469 studies on burden and determinants of neck pain, and judged 249 to be scientifically admissible; 101 articles related to the burden and determinants of neck pain in the general population. Incidence ranged from 0.055 per 1000 person years (disc herniation with radiculopathy) to 213 per 1000 persons (self-reported neck pain). Incidence of neck injuries during competitive sports ranged from 0.02 to 21 per 1000 exposures. The 12-month prevalence of pain typically ranged between 30% and 50%; the 12-month prevalence of activity-limiting pain was 1.7% to 11.5%. Neck pain was more prevalent among women and prevalence peaked in middle age. Risk factors for neck pain included genetics, poor psychological health, and exposure to tobacco. Disc degeneration was not identified as a risk factor. The use of sporting gear (helmets, face shields) to prevent other types of injury was not associated with increased neck injuries in bicycling, hockey, or skiing.

CONCLUSION

Neck pain is common. Nonmodifiable risk factors for neck pain included age, gender, and genetics. Modifiable factors included smoking, exposure to tobacco, and psychological health. Disc degeneration was not identified as a risk factor. Future research should concentrate on longitudinal designs exploring preventive strategies and modifiable risk factors for neck pain.

Development and validation of diagnostic criteria for carpal tunnel syndrome

PURPOSE

To develop clinical diagnostic criteria for carpal tunnel syndrome (CTS) that modeled the clinical diagnostic practices of experts.

METHODS

Fifty-seven clinical findings associated with CTS had been ranked previously in order of diagnostic importance using Delphi as a method of establishing consensus among a panel of expert clinicians. The 8 most highly ranked criteria then were placed into all possible combinations to create 256 unique case histories. Two new panels of experts rated these case histories. One panel made a binary evaluation as to whether the case history did or did not represent CTS. This allowed the development of a logistic regression model that had the probability of carpal tunnel syndrome as the dependent variable and the weighted diagnostic criteria as the independent variables. This model then was validated against the judgments of the second panel of clinicians who estimated the probability of CTS for each of the same case histories.

RESULTS

The correlation between the probability of CTS predicted by the model and the panel of clinicians was 0.71.

CONCLUSIONS

The most important clinical diagnostic criteria for CTS as identified from a larger pool of potential diagnostic items through a consensus approach using Delphi were weighted and found to correlate well with the judgments of a new panel of clinicians. By improving the consistency of the diagnosis of CTS these criteria should lead to more effective treatment and a better understanding of the effect of workplace exposures in the development of this condition. A methodology that emphasizes a rigorous approach to item generation and item reduction through expert consensus, followed by validation, may represent a template for establishing consensus among experts on other controversial clinical issues.

TYPE OF STUDY/LEVEL OF EVIDENCE

Diagnostic, Level I.

Evaluation of work-related carpal tunnel syndrome

OBJECTIVES

Carpal tunnel syndrome (CTS) is common in the industrial setting but there are still some advocates who argue that CTS is not a work related problem. There are also controversies about the proper way to establish the diagnosis and whether screening for CTS in the industrial setting is warranted.

METHODS

A comprehensive literature review.

RESULTS

The literature does demonstrate that the prevalence of CTS in the industrial setting is significantly higher than in the general population. Numerous epidemiologic studies have identified independent risk factors, which include repetitiveness of work, forceful exertions, mechanical stress, posture, and vibration as well as several personal co-factors. The strength of these associations are discussed. The diagnostic criteria for establishing work-related CTS are discussed as well as the effectiveness of various screening methods that are commonly used in the workplace. The sensitivity and specificity of nerve conduction studies to establish or confirm the diagnosis of CTS is presented along with normative data for the industrial worker.

CONCLUSIONS

CTS has both work-related and personal risk factors. The diagnosis is best established using a combination of history, symptom distribution and confirmation using the relative latency of median sensory testing using normative data. Screening for CTS in the industrial setting has questionable benefit.

Levels of agreement of nerve conduction studies and symptoms in workers at risk of carpal tunnel syndrome

OBJECTIVE

Information is required on levels of agreement between different sets of median nerve conduction studies (NCS) and symptoms of carpal tunnel syndrome (CTS) in at-risk subjects.

METHODS

We performed a reanalysis of an extensive data set from a population of 114 "highly exposed" meat workers (without prior diagnosis of CTS), who were interviewed for the presence of current symptoms typical of CTS and systematically submitted to median NCS.

RESULTS

Agreement between presence/absence of symptoms and NCS normal/abnormal findings ranged from 81% for wrist sensory latency (WSL) to 49% for motor conduction velocity wrist-to-palm (MCV-WP) in the nondominant hands (from 60% to 50%, respectively, in the dominant hands). Mean values of WSL, sensory conduction velocity-WP (SCV-WP), wrist motor latency, MCV-WP, and the SCV-WP/SCV-elbow-to-wrist ratio all showed significant differences between symptomatic and asymptomatic workers. In nondominant hands, these parameters all reached significant P values at chi-squared tests for kappa coefficients of agreement, the best kappa coefficients being 0.57 for WSL and 0.40 for SCV-WP. However, in the dominant hand only SCV-WP reached significance (kappa coefficient=0.20).

CONCLUSIONS

Given the importance of the dominant hand in working populations, these data support use of SCV-WP (or WSL) as an informative NCS parameter for occupational studies on CTS.

Ergonomic stressors and upper extremity musculoskeletal disorders in automobile manufacturing: a one year follow up study

AIMS

To estimate the one year cumulative incidence and persistence of upper extremity (UE) soft tissue disorders, in a fixed cohort of automotive manufacturing workers, and to quantify their associations with ergonomic exposures.

METHODS

At baseline and at follow up, cases of UE musculoskeletal disorders were determined by interviewer administered questionnaire and standardised physical examination of the upper extremities. The interview obtained new data on psychosocial strain and updated the medical and work histories. An index of exposure to ergonomic stressors, obtained at baseline interview, was the primary independent variable. Cumulative incidence and persistence of UE disorders (defined both by symptoms and by physical examination plus symptoms) were analysed in relation to baseline ergonomic exposures, adjusting for other covariates. The incidence of new disorders was modelled using multivariate proportional hazards regression among workers who were not cases in the first year and the prevalence on both occasions was modelled by repeated measures analysis.

RESULTS

A total of 820 workers (69% of eligible cohort members) was examined. Follow up varied slightly by department group but not by baseline exposure level or other characteristics. Among the non-cases at baseline, the cumulative incidence of UE disorders was 14% by symptoms and 12% by symptoms plus examination findings. These rates increased with index of physical exposures primarily among subjects who had the same jobs at follow up as at baseline. Increased exposure during follow up increased risk of incidence. The persistence of UE disorders from baseline to follow up examination was nearly 60% and somewhat associated with baseline exposure score.

CONCLUSIONS

These longitudinal results confirm the previous cross sectional associations of UE musculoskeletal disorders with exposure to combined ergonomic stressors. The exposure-response relation was similar for incident cases defined by symptoms alone and those confirmed by physical examination.

Pyridoxine hydrochloride treatment of carpal tunnel syndrome: a review

It has been hypothesized that idiopathic carpal tunnel syndrome (CTS) is a manifestation of vitamin B6 deficiency. Some claim that B6 supplementation can alleviate symptoms. Others argue that pain relief occurs because of vitamin B6's anti-nociceptive properties or because B6 supplementation addresses an unrecognized peripheral neuropathy. Few studies on CTS and B6 employed electrodiagnostic techniques in diagnosis, and few showed a correlation between symptoms and improved electrodiagnostic parameters with supplementation. Other studies failed to measure or estimate B6 levels. Nevertheless, it appears reasonable to recommend vitamin B6 supplementation to people with CTS. Some patients will improve symptomatically with low risks of toxicity in recommended doses.

Peripheral Neuropathy

This chapter focuses on peripheral neuropathy, which is the third or fourth most common neurologic disorder, even among the elderly. It begins with a description of the classification system for peripheral neuropathies. Because the underlying etiology or precipitating events of peripheral neuropathy are identifiable for the majority of affected individuals, epidemiologic research has largely focused on descriptive studies of disease frequency or on identifying the factors that modify the influence of the already existing risk factors. Three of the most common neuropathies are covered in detail: diabetic neuropathy, carpal tunnel syndrome, and Guillain–Barré syndrome. Each of these conditions is discussed in terms of distribution and risk factors, and is concluded with a discussion of future research directions to address unanswered questions. The chapter emphasizes methodologic approaches that that could be employed to improve the rigor of studies of these conditions.

Clinical surveillance of carpal tunnel syndrome in two areas of the United Kingdom, 1991-2001

OBJECTIVE

To study the demographic characteristics of patients with carpal tunnel syndrome and changes in incidence over time.

METHODS

Prospective collection of neurophysiological and clinical data on all patients presenting to the subregional department of clinical neurophysiology in Canterbury, UK, from 1992 to 2001 and to the electromyography clinic in St Luke's Hospital, Huddersfield, UK, from 1991 to 1993.

RESULTS

6245 new cases of neurophysiologically confirmed carpal tunnel syndrome were identified in Canterbury and 590 in Huddersfield. The average annual incidences (per 100,000) were 139.4 for women and 67.2 for men in East Kent, and 83.2 for women and 48.0 for men in Huddersfield. Corrected to the WHO European standard population these rates were 120.5 for women and 60.0 for men in East Kent, and 61.5 for women and 35.0 for men in Huddersfield. Between 1992 and 2001 there was an increase in the number of confirmed cases in East Kent but a decrease in their average severity. The age distributions were bimodal with a peak in the 50-54 age group and a second peak between 75 and 84 years. Over half the cases were bilateral. The disorder was consistently worse in the elderly, and more severe in men than in women in all age groups.

CONCLUSIONS

The age distributions of unselected cases of carpal tunnel syndrome in both clinics differ markedly from that usually portrayed in surgical series. There was a significant increase in cases diagnosed between 1992 and 2001 in Canterbury, probably the result of increased ascertainment of milder cases. Median nerve impairment is more severe in the elderly and in men at all ages.

Relationship Between Carpal Tunnel Syndrome and Wrist Angle in Computer Workers

Carpal tunnel syndrome (CTS) is the most widely known entrapment neuropathy. The aim of this study was to assess the incidence of CTS in a group of computer workers by typical symptoms, median nerve conduction studies, and their combinations. The posture of extended wrists while typing on a computer keyboard seems to be a predisposing factor for CTS. However, the correlation between wrist extension angle and the incidence of CTS is not well known. Forty-five subjects (mean age, 38.8 +/- 7.8 years) who used a computer for more than 6 hours daily in a medical center in southern Taiwan were studied. All completed questionnaires to ascertain their age, employment duration, dominant hand, and the severity of symptoms. Physical examinations (Tinel's sign and Phalen's test) were performed by a physician. The maximal wrist extension angle when typing on a computer keyboard was also measured by the same physician. Nerve conduction studies were performed on each subject to determine the severity of CTS. Results showed that the incidence of CTS in the computer workers was 16.7% (15 of 90 hands). Twelve subjects showed electrodiagnostic evidence of CTS: it involved the dominant hand in seven, the non-dominant hand in two, and bilateral hands in three. The severity of clinical symptoms was compatible with the findings of the nerve conduction studies. Among the major predisposing factors, we found significant correlation between CTS development and the wrist extension angle while typing on a computer keyboard. Computer workers who kept their wrists extended by more than 20 degrees were at greater risk of developing CTS.

Neurobehavioral performance and work experience in Florida farmworkers

Farmworkers experience many work-related hazards, including exposure to neurotoxicants. We compared neurobehavioral performance of 288 farmworkers in central Florida who had done farm work for at least 1 month with 51 controls who had not. Most of the farmworkers had worked in one or more of three types of agriculture: ornamental ferns, nurseries, or citrus fruit. We collected information on farm work history in a structured interview and evaluated neurobehavioral performance using a battery of eight tests. Analyses were adjusted for established confounders including age, sex, education, and acculturation. Ever having done farm work was associated with poor performance on four tests--digit span [odds ratio (OR) = 1.90; 95% confidence interval (CI), 1.02-3.53], tapping (coefficient = 4.13; 95% CI, 0.00-8.27), Santa Ana test (coefficient = 1.34; 95% CI, 0.29-2.39), and postural sway (coefficient = 4.74; 95% CI, -2.20 to 11.7)--but had little effect on four others: symbol digit latency, vibrotactile threshold, visual contrast sensitivity, and grip strength. Associations with farm work were similar in magnitude to associations with personal characteristics such as age and sex. Longer duration of farm work was associated with worse performance. Associations with fern work were more consistent than associations with nursery or citrus work. Deficits related to the duration of work experience were seen in former as well as current farmworkers, and decreased performance was related to chronic exposure even in the absence of a history of pesticide poisoning. We conclude that long-term experience of farm work is associated with measurable deficits in cognitive and psychomotor function.

Functional deficits in carpal tunnel syndrome

BACKGROUND

Carpal tunnel syndrome (CTS) is a major occupational illness in the US. The Wisconsin Test is a quantitative computer-controlled test battery designed for measuring sensory and psychomotor function. Subjects were recruited from industrial jobs at high-risk for CTS to determine if subtle sensory and motor deficits were observable in a working population. Outcomes were studied for potential use as an injury surveillance instrument.

METHODS

A total of 208 subjects participated (72 males and 136 females). Participants completed a symptom survey, were given a physical examination, administered nerve conduction tests, and were tested using the Wisconsin Test battery.

RESULTS

The greatest functional deficits were observed when nerve conduction findings were positive and were accompanied by either positive symptom survey outcomes or positive physical exam findings. The presence of symptoms alone were not significantly associated with motor deficits and no significant sensory threshold differences were observed among subjects categorized using any single criterion (i.e., nerve conduction, symptom reports, or examination).

CONCLUSIONS

Measurable and quantifiable sensory and psychomotor deficits were observed in a working industrial population, and were greatest when positive symptoms or physical exam was accompanied by positive nerve conduction test findings. These data show that clinical criteria used in the diagnosis of CTS corresponds with functional psychomotor and sensory impairments measured in these tests.

[Paresthesia and/or pain affecting the hand and/or wrist as a referral for electrodiagnostic studies]

To study the reasons for referral to electrodiagnostic evaluation, 490 patients referred for electrodiagnostic evaluation to two laboratories (UNIFESP and UNEF) answered the following question: "What was the reason that brought you to look for a physician and that led him to ask this examination?" Paresthesia and/or pain were answered as the main reason by 175 of them (26% UNIFESP and 40% UNEF). The electromyographical examinations were normal in 30.8% and 35.3% and involvement of the median nerve at the wrist was detected in 5 9% and 51.5% of them. Nocturnal symptoms and paresthesia were commonly noted in both groups of patients; they, however, were not able to separate the patients with and without median nerve compression at the wrist. The question asked seems to be a useful selection instrument, to select two similar symptomatic samples of patients from two laboratories serving with very different target populations.

Ultrasonographic measurement of median nerve cross-sectional area in idiopathic carpal tunnel syndrome: Diagnostic accuracy

Severity-correlated enlargement of the median nerve occurs in idiopathic carpal tunnel syndrome (CTS). We determined whether measurement of the nerve cross-sectional area was useful in making the diagnosis of CTS. In 414 wrists of 275 patients with clinically diagnosed idiopathic CTS and 408 wrists of 408 controls, we made ultrasonographic measurements of the nerve area at the distal (distal edge of the flexor retinaculum), mid (hook of the hamate), and proximal carpal tunnel (wrist crease). Criteria based on the area at a single level yielded sensitivities of 43-57% and specificities of 96-97%. Use of the mean carpal nerve area (average of the areas at the three levels) improved the results (sensitivity, 67%; specificity, 97%), which was as sensitive as the nerve conduction studies (NCS). In the NCS, we obtained sensitivities of 66% for the distal motor nerve latency and 67% for the distal sensory nerve latency, with specificities of 97% for each. A combination of the mean carpal nerve area and NCS criteria yielded a sensitivity of 84% and a specificity of 94%. The clinical implications of these findings for the diagnosis of CTS are discussed.

Active epidemiological surveillance of musculoskeletal disorders in a shoe factory

AIMS

(1) To evaluate an active method of surveillance of musculoskeletal disorders (MSDs). (2) To compare different criteria for deciding whether or not a work situation could be considered at high risk of MSDs in a large, modern shoe factory.

METHODS

A total of 253 blue collar workers were interviewed and examined by the same physician in 1996; 191 of them were re-examined in 1997. Risk factors of MSDs were assessed for each worker by standardised job site work analysis. Prevalence and incidence rates of carpal tunnel syndrome, rotator cuff syndrome, and tension neck syndrome were calculated for each of the nine main types of work situation. Different criteria used to assess situations with high risk of MSDs were compared.

RESULTS

On the basis of prevalence data, three types of work situation were detected to be at high risk of MSDs: cutting, sewing, and assembly preparation. The three types of work situations identified on the basis of incidence data (sewing preparation, mechanised assembling, and finishing) were different from those identified by prevalence data. At least one recognised risk factor for MSDs was identified for all groups of work situations. The ergonomic risk could be considered as serious for the four types of work situation having the highest ergonomic scores (sewing, assembly preparation, pasting, and cutting).

CONCLUSION

The results of the health surveillance method depend largely on the definition of the criteria used to define the risk of MSDs. The criteria based on incidence data are more valid than those based on prevalence data. Health and risk factor surveillance must be combined to predict the risk of MSDs in the company. However, exposure assessment plays a greater role in determining the priorities for ergonomic intervention.

Carpal tunnel syndrome in railroad workers

OBJECTIVE

To determine, within a specific industry, if carpal tunnel syndrome (CTS) is associated with job classification or other personal risk factors. To determine if surgical intervention for the treatment of CTS is indicated on the basis of electrodiagnostic criteria.

DESIGN

More than 2500 claimants who screened positive for CTS were subjected to a formal history, physical examination, and electrodiagnostic studies. A total of 900 subjects were randomly selected for this study. The presence of CTS was determined by a method of comparing median minus ulnar nerve distal latency differential (MUD).

RESULTS

There was a statistically significant relationship between CTS and body mass index (P < 0.001), wrist index (P < 0.001), and age (P < 0.001). A total of 43.4% of the participants (391/900) and 38.6% of the wrists (694/1800) had either positive or borderline findings for CTS. There was no difference between the left and right hands. There was no association between job classification and the presence of CTS. Using MUD criteria, more than half of the participants presumed to have CTS did not meet the requirements for diagnosis. Applying the same MUD criteria to all surgical cases, the indication for surgery could not be determined in one-third of the cases (33%, 83/248).

CONCLUSIONS

In the population claiming CTS caused by railroad occupations, there was a significant association between CTS and body mass index, age, and wrist index, but not job classification. More than half of the study group and one-third of the surgical subset had normal MUD data.

Transient hand paresthesias in Champagne vineyard workers

BACKGROUND

The aim of the study was to assess the prevalence of hand paresthesias (HP) and their relationship with pruning activities.

METHODS

A cross-sectional study was conducted among 537 workers pruning grapevines in the region of Champagne. All workers completed a questionnaire about nocturnal HP and musculoskeletal pain during the preceding 12-month period.

RESULTS

The 12-month prevalence of nocturnal HP and hand-wrist pain were 37 and 12%, respectively. HP, predominantly affecting the dominant hand, only began during the pruning period and ended after the pruning season in 90% of cases. HP were transient in most cases, with a mean duration of symptoms of 3.3 +/- 3.2 months. Risk factors associated with HP were: female gender (OR = 2.3 [1.3-3.0]), being overweight (OR = 1.6 [1.1-2.5]), payment on a piecework basis (OR = 2.0 [1.2-2.3]) and traditional blade sharpening method (OR = 1.7 [1.1-2.7]). HP were less frequent in employees who used electric pruning shears (OR = 0.5 [0.2-1.6], P = 0.09).

CONCLUSIONS

The development of HP, which affected a third of employees, was different from HP observed in industrial workers since most vineyard workers recovered without medical treatment after the pruning season.

[Carpal tunnel syndrome: controversies regarding clinical and electrodiagnosis and its work-relatedness]

The diagnosis of carpal tunnel syndrome (CTS) may be difficult because paresthesias and tingling in the upper limbs are commonly reported in the general population. These symptoms are poorly correlated with changes of nerve conduction studies of the median nerve. CTS should be diagnosed only when typical symptoms are associated with significant electrophysiological abnormalities. The association of CTS with work is highly controversial.

The Southampton examination schedule for the diagnosis of musculoskeletal disorders of the upper limb

OBJECTIVES

Following a consensus statement from a multidisciplinary UK workshop, a structured examination schedule was developed for the diagnosis and classification of musculoskeletal disorders of the upper limb. The aim of this study was to test the repeatability and the validity of the newly developed schedule in a hospital setting.

METHOD

43 consecutive referrals to a soft tissue rheumatism clinic (group 1) and 45 subjects with one of a list of specific upper limb disorders (including shoulder capsulitis, rotator cuff tendinitis, lateral epicondylitis and tenosynovitis) (group 2), were recruited from hospital rheumatology and orthopaedic outpatient clinics. All 88 subjects were examined by a research nurse (blinded to diagnosis), and everyone from group 1 was independently examined by a rheumatologist. Between observer agreement was assessed among subjects from group 1 by calculating Cohen's kappa for dichotomous physical signs, and mean differences with limits of agreement for measured ranges of joint movement. To assess the validity of the examination, a pre-defined algorithm was applied to the nurse's examination findings in patients from both groups, and the sensitivity and specificity of the derived diagnoses were determined in comparison with the clinic's independent diagnosis as the reference standard.

RESULTS

The between observer repeatability of physical signs varied from good to excellent, with kappa coefficients of 0.66 to 1.00 for most categorical observations, and mean absolute differences of 1.4 degrees -11.9 degrees for measurements of shoulder movement. The sensitivity of the schedule in comparison with the reference standard varied between diagnoses from 58%-100%, while the specificities ranged from 84%-100%. The nurse and the clinic physician generally agreed in their diagnoses, but in the presence of shoulder capsulitis the nurse usually also diagnosed shoulder tendinitis, whereas the clinic physician did not.

CONCLUSION

The new examination protocol is repeatable and gives acceptable diagnostic accuracy in a hospital setting. Examination can feasibly be delegated to a trained nurse, and the protocol has the benefit of face and construct validity as well as consensus backing. Its performance in the community, where disease is less clear cut, merits separate evaluation, and further refinement is needed to discriminate between discrete pathologies at the shoulder.

The value of diagnostic testing in carpal tunnel syndrome

The purpose of this study was to determine the validity of tests or a combination of tests for the diagnosis of carpal tunnel syndrome. Three groups of 50 subjects each were studied: group 1 had definite carpal tunnel syndrome as defined by history, clinical presentation, and improvement of symptoms following carpal tunnel release; group 2 had a variety of nontraumatic upper extremity disorders other than carpal tunnel syndrome; and group 3 subjects were asymptomatic healthy volunteers. Subjects submitted a self-administered hand diagram, and were queried about night pain, symptom duration, and coexistent medical conditions. Phalen's test, Tinel's sign, Durkan's compression test, and Semmes-Weinstein monofilament testing both before and after a Phalen's maneuver for 5 minutes were performed on each subject. Grip and pinch strengths were measured. Univariate analysis of groups 1 and 2 showed that the tests with the highest sensitivity were Durkan's compression test (89%), Semmes-Weinstein testing after Phalen's maneuver (83%), and hand diagram scores (76%). Night pain was a sensitive symptom predictor (96%). The most specific tests were the hand diagram (76%) and Tinel's sign (71%). Analysis of groups 1 and 3 without group 2 increased the specificity and predictive value of a positive test. A regression model was used to develop a multivariate equation with 4 variables. If a patient has an abnormal hand diagram, abnormal sensibility by Semmes-Weinstein testing in wrist-neutral position, a positive Durkan's test, and night pain, the probability that carpal tunnel syndrome will be correctly diagnosed is 0.86. If all 4 of these conditions are normal, the probability that the patient has carpal tunnel syndrome is 0.0068. We found that the addition of electrodiagnostic tests did not increase the diagnostic power of the combination of 4 clinical tests.

Prevalence and incidence of carpal tunnel syndrome in a meat packing plant

OBJECTIVES

To determine prevalence and incidence of carpal tunnel syndrome (CTS) in a modern meat packing plant. The secondary objective was to explore the relation between ethnicity and CTS.

METHODS

Six hundred and sixty five workers were interviewed and examined to find the prevalence of CTS. Subsequently, 421 workers without CTS were followed up and examined at a median interval of 253 days; of those, 333 remained without CTS and were again examined at a median interval of 148 days.

RESULTS

The prevalence and incidence of CTS was 21% and 11/100 person-years, respectively. The incidence for Asian mixed, white, and other ethnicities was 12.0, 12.2, and 7.2 cases/100 person-years, respectively. The observed incidence for men and women was 9.7 and 18.4 cases/100 person-years, respectively. This difference was not quite significant (p = 0.068) with an estimated relative risk (women v men) of 1.9 (95% confidence interval (95% CI) 0.9 to 3.8). The interaction between sex and use of tools was significant (p = 0.04), however, although the relative risk for CTS in women who used tools was 4.2 the numbers were small and not significant. The relative risk for men who used tools was 0.64 and not significant. The percentage of incident cases with comorbid disease was only 6.3% (3/47).

CONCLUSIONS

The prevalence and incidence of CTS in this workforce were higher than in the general population. However, the prevalence of CTS in this modern, mechanised plant was not significantly different from that reported in older plants. No relation was found between ethnicity, age, body mass index, and CTS for either prevalence or incidence. Comorbid disease among the cases of CTS is significantly less than that found in other industry.

Occupational upper extremity disorders in the federal workforce. Prevalence, health care expenditures, and patterns of work disability

Upper extremity disorders (UEDs) account for a significant number of work-related illnesses in the US workforce. Little information exists on the distribution of UEDs, their associated health care and indemnity costs, or patterns of work disability. The study presented is an analysis of upper extremity claims within the federal workforce. In this study, the universe consisted of all claims accepted by the US Department of Labor, Office of Workers' Compensation Programs (OWCP), from October 1, 1993, through September 30, 1994. A total of 185,927 claims of notices of injury were processed during the study period, and of these, 8,147 or 4.4% had an UED diagnosis coded according to the International Classification of Diseases, Clinical Modification (ICD-9-CM). 5,844 claims involved a single UED diagnosis and were the only claims field by these employees between October 1, 1990, and September 30, 1994. These single claims with single diagnoses comprised the sample for further analysis. Mononeuritis and enthesopathies of the upper limb were the most common diagnoses, accounting for 43% and 31% of the claims, respectively. Women had a higher proportion of carpal tunnel syndrome, "unspecified" mononeuritis, and "unspecified" enthesopathies. The majority of claimants for both the mononeuritis- and enthesopathy-related diagnoses were between 31 and 50 years of age, received only health care benefits, and did not incur wage loss. Health care costs for mononeuritis and enthesopathy claims were $12,228,755 (M = $2,849). Carpal tunnel syndrome (CTS) and enthesopathy of the elbow were the most costly diagnoses, accounting for 57% and 16% of the total, respectively. Surgical services represented the highest expenditures in CTS claims. Physical therapy accounted for the majority of health care costs for enthesopathy cases. The mean number of workdays lost for CTS and enthesopathy claims were 84 and 79, and the average indemnity costs were $4,941 and $4,477, respectively. These findings indicate that while UEDs represent a relatively small percentage of all workers' compensation cases, the health care and indemnity costs are considerable. Also mean duration and pattern of work disability revealed that these disorders can result in chronic work disability similar to that observed in low back pain. The results highlight the need to determine whether interventions that account for the majority of costs significantly impact long-term outcomes. There is also a need to identify risk factors for prolonged disability in those who experience problems with delayed recovery.

Preliminary evaluation of a sensory and psychomotor functional test battery for carpal tunnel syndrome: Part 1--Confirmed cases and normal subjects

Two new computer-controlled functional tests were developed, known as the Wisconsin test battery, for carpal tunnel syndrome (CTS). The gap detection sensory test quantifies tactile thresholds for areas of the hand innervated by the median nerve. The rapid pinch and release psychomotor test measures the initiation and control of specific muscles innervated by the median nerve motor branch. Ten confirmed CTS patients (based on electrophysiological parameters and examination; 18 CTS hands) and eight confirmed normal subjects (16 hands) with a similar average age were administered both tests. The CTS patients showed significant functional deficits for both tactility and psychomotor tests. Average CTS performance was 24 to 104% poorer than for the normal subjects, depending on the performance measure. The results indicated high correlations (r = 0.5 to 0.8) between median nerve electrophysiological parameters and tactility or psychomotor performance variables. No single functional test variable had sufficient sensitivity for detecting CTS among the subject pool. The combination of the two tests using 95% confidence level cutoff points achieved a sensitivity of 0.78 and a specificity of 0.81. Stepwise discriminant analysis resulted in two performance variables capable of a sensitivity of 0.72 and a specificity of 0.94 for differentiating well-defined CTS subjects from normal subjects. Despite these promising results, limitations of the study include small sample size and subject selection bias. Further studies are needed for verifying the utility of the functional test battery for detecting CTS in a general population.

Ergonomic risk exposure and upper-extremity cumulative trauma disorders in a maquiladora medical devices manufacturing plant

Workers at a Nogales, Mexico, maquiladora plant that assembles medical devices were studied to determine the prevalence of upper-extremity cumulative trauma disorders (CTD). Subjects included production workers employed 6 months or longer; of the 148 eligible workers, 145 (98%) participated. Subjects had a mean age of 24.6 years (SD = 5.2; range, 17 to 45) and the mean length of employment was 3.5 years (SD = 2.5; range, 0.5 to 14). Job tasks were videotaped and analyzed for ergonomic risk factors, using pre-defined criteria. All jobs performed by study subjects were found to involve one or more ergonomic risk factors associated with the development of CTD. A CTD questionnaire and screening physical examination format, similar to that used by the National Institute of Occupational Safety and Health (NIOSH) in a chicken processing plant study, were administered. Period prevalence of CTD within the previous year, as reported on the questionnaire, was 28%. Prevalence of CTD was 17%, using data from the screening physical examination. Point prevalence (current pain data from the questionnaire plus positive symptoms on the screening physical examination) was 15%. CTD was reported more frequently in women than men (46% and 25%, respectively; P < 0.05) and in subjects who had worked at the plant less than one year (50%; P < 0.05). Workforce turnover (3% monthly) may have resulted in those affected by CTD leaving employment, reducing the apparent CTD rate in experienced workers.

Long-term symptom outcomes of carpal tunnel syndrome and its treatment

A retrospective follow-up study of a population-based case series was conducted to determine the clinical course and outcomes of carpal tunnel syndrome (CTS). A total of 425 cases first diagnosed between 1979 and 1988 were followed through 1993. Among patients who did not have surgery, median duration of symptoms was between 6 and 9 months, but 22% had symptoms for 8 years or longer. Patients who had surgery were about 6 times more likely to have resolution of their symptoms than were patients who did not have surgery. Patients who had surgery 3 or more years after their initial diagnosis of CTS were less than half as likely to have symptom resolution than were patients who had surgery within 3 years of diagnosis. The results indicate that surgery is a highly effective treatment, but duration of CTS prior to surgery is a key determinant of surgical outcome.

Outcome assessment for carpal tunnel surgery: the relative responsiveness of generic, arthritis-specific, disease-specific, and physical examination measures

Clinical evaluation of outcome after treatment of carpal tunnel syndrome has not been standardized. To assess the value of various clinical and questionnaire measures for the assessment of outcome after carpal tunnel surgery, we surveyed 22 patients 1 day before and 3 months after carpal tunnel release with the following measures: the Medical Outcomes Study 36-item short form health survey, the Arthritis Impact Measurement Scale, the Brigham and Women's Hospital carpal tunnel questionnaire, wrist range of motion, power pinch grip strength, pressure sensibility, and dexterity. Significant changes, all in the direction of improved health status postoperatively, were noted in the following scales or measures: the Arthritis Impact Measurement Scale pain, satisfaction, health perception, arthritis impact, and symptom scales; the Brigham and Women's Hospital symptom and function scales; the short form health survey's physical role, emotional role, and bodily pain scales; and the measurement of dexterity. In this study, standardized questionnaires were more sensitive to the clinical change produced by carpal tunnel surgery than many commonly performed physical measures of outcome. The condition-specific questionnaire was more sensitive to change than were more generic questionnaires.

Cumulative trauma disorders and carpal tunnel syndrome: Sorting out the confusion

Chronic work injury will be implicated as a cause of upper extremity musculoskeletal disorders in increasing numbers of patients. A wide variety of conditions, some with a specific diagnosis (eg, carpal tunnel syndrome) and a known response to treatment in contrast to more generalized disorders (eg, tendonitis) where the prognosis is uncertain form part of the spectrum. Experience has demonstrated that as the diagnosis becomes less specific, job related and emotional factors can significantly affect the patient's presentation, response to treatment and timing to return to work. Care needs to be exercised in implicating work in the etiology. General terms such as ‘cumulative trauma disorder’ and ‘repetitive strain injury’ need to be avoided.

Upper extremity disorders: a literature review to determine work-relatedness

The objective of this review is to establish whether the medical literature validates a causal relationship between upper extremity disorders and work activities. Selected articles were reviewed using a Diagnostic Medical Criteria. Articles meeting this criteria were further reviewed for validity. Only 14 of 52 reviewed articles were felt to encompass medical criteria. However, these articles also contained what appear to be major validity flaws. Very little of the written material dealing with the issue of work-related upper extremity conditions incorporates what are felt to be sound medical diagnostic criteria in the definition and identification of these conditions. None of the reviewed studies have established a causal relationship between distinct medical entities and work activities. Further research using well constructed studies that incorporate reliable epidemiologic and accepted diagnostic criteria is needed. In this manner, the best of the medical and epidemiologic fields can be applied to solving these problems.

Psychophysical studies of repetitive wrist flexion and extension

The purpose of this experiment was to investigate the feasibility of using psychophysical methods to determine maximum acceptable forces for various types and frequencies of repetitive wrist motion. Four adjustable work stations were built to simulate repetitive wrist flexion with a power grip, wrist flexion with a pinch grip, and wrist extension with a power grip. The study consisted of two separate experiments. Subjects worked for two days per week during the first experiment, and five days per week during the second experiment. Fifteen women completed the first experiment, working seven hours each day, two days per week, for 20 days. Repetition rates of 2, 5, 10, 15 and 20 motions per minute were used with each flexion and extension task. Maximum acceptable torques were determined for the various motions, grips, and repetition rates without dramatic changes in wrist strength, tactile sensitivity, or number of symptoms. Fourteen different women completed the second experiment, performing a wrist flexion motion (power grip) fifteen times per minute, seven hours per day, five days per week, for 23 days. There were no significant differences in maximum acceptable torque from day to day. However, the average maximum acceptable torque for a five days per week exposure was 36.3% lower than for the same task performed two days per week. Assuming that maximum acceptable torques decrease 36.3% for other repetition rates and motions, tables of maximum acceptable force were developed for female wrist flexion (power grip), female wrist flexion (pinch grip), and female wrist extension (power grip).

Surveillance and prevention of work-related carpal tunnel syndrome: an application of the Sentinel Events Notification System for Occupational Risks

In response to limitations in state-based, occupational disease surveillance, the California Department of Health Services developed a model for provider- and case-based surveillance of work-related carpal tunnel syndrome. The objectives were to enhance case reporting, identify risk factors and high-risk work sites, and link preventive interventions to work sites and the broader community. Using elements from surveillance of communicable diseases and sentinel health events, a model was integrated into the pre-existing reporting system in one California county. Between 1989 and 1991, 54 Santa Clara County health care providers reported 382 suspected cases, of which 365 from 195 work sites met reporting guidelines. Risk factors were profiled from interviews of 135 prioritized cases and 38 employers. Of 24 work sites prioritized for a free, voluntary, nonenforcement inspection, 18 refused and 6 completed an on-site visit. Sentinel Event Notification System for Occupational Risks (SENSOR) captured many cases not reported to the pre-existing reporting system. Case interviews indicated a profile of symptoms and signs, treatment, and exposure to uncontrolled occupational risk factors, including a lack of training on ergonomics hazards. Employer health insurance, rather than workers' compensation, was the apparent source of payment for most medical bills. Employers lacked knowledge and motivation to reduce ergonomic risks. Governmentally mandated occupational ergonomics standards are urgently needed.

Outcome of carpal tunnel surgery in Washington State workers' compensation

All cases of occupational carpal tunnel syndrome (OCTS) who received surgery for this condition in the Washington State workers' compensation system were identified using claim and physician billing databases. One hundred ninety-one incident surgical cases were identified between July 1, 1987 and December 31, 1987, and were followed up a mean of 3 years postoperatively for clinical, disability, and return to work outcomes. Medical record and claim file review was required for clinical and employment information. The mean age of all patients was 36.6 years, 48% were female, and 40% received bilateral surgery. The mean time from claim filing to surgery was 187 days. Ninety-eight percent of cases met the National Institute for Occupational Safety and Health (NIOSH) case definition for OCTS. Relief of pain was complete or modest in 86% (124/145) and only 14% of cases reported no improvement in symptoms. Mean duration of disability (time loss) postoperatively was nearly 4 months, and 8% of cases exceeded 1 year of time loss. The majority of cases returned to their same job (67%) or to a different job (15%). Workers in high risk occupations were less likely to return to the same job after CTS surgery compared to those in lower risk occupations (61% vs. 75%, p = 0.08). In this population, no association was seen between any outcome and age, gender, marital status, or baseline wage. Duration of disability was not significantly related to preoperative severity of OCTS or to more specific case criteria for this condition.(ABSTRACT TRUNCATED AT 250 WORDS)