An evaluation of gender, body mass index, wrist circumference and wrist ratio as independent risk factors for carpal tunnel syndrome

Carpal tunnel syndrome prediction with machine learning algorithms using anthropometric and strength-based measurement

OBJECTIVES

Carpal tunnel syndrome (CTS) stands as the most prevalent upper extremity entrapment neuropathy, with a multifaceted etiology encompassing various risk factors. This study aimed to investigate whether anthropometric measurements of the hand, grip strength, and pinch strength could serve as predictive indicators for CTS through machine learning techniques.

METHODS

Enrollment encompassed patients exhibiting CTS symptoms (n = 56) and asymptomatic healthy controls (n = 56), with confirmation via electrophysiological assessments. Anthropometric measurements of the hand were obtained using a digital caliper, grip strength was gauged via a digital handgrip dynamometer, and pinch strengths were assessed using a pinchmeter. A comprehensive analysis was conducted employing four most common and effective machine learning algorithms, integrating thorough parameter tuning and cross-validation procedures. Additionally, the outcomes of variable importance were presented.

RESULTS

Among the diverse algorithms, Random Forests (accuracy of 89.474%, F1-score of 0.905, and kappa value of 0.789) and XGBoost (accuracy of 86.842%, F1-score of 0.878, and kappa value of 0.736) emerged as the top-performing choices based on distinct classification metrics. In addition, using variable importance calculations specific to these models, the most important variables were found to be wrist circumference, hand width, hand grip strength, tip pinch, key pinch, and middle finger length.

CONCLUSION

The findings of this study demonstrated that wrist circumference, hand width, hand grip strength, tip pinch, key pinch, and middle finger length can be utilized as reliable indicators of CTS. Also, the model developed herein, along with the identified crucial variables, could serve as an informative guide for healthcare professionals, enhancing precision and efficacy in CTS prediction.

An Evaluation of Variations in the Carpal Tunnel Dimensions of Adult Subjects in a Hospital-Based Population: An Ultrasonographic Cross-Sectional Study

Background The carpal tunnel is a groove that spans the palm as a 'U.' The ulnar and radial sides of the wrist are made up of the scaphoid tubercle and trapezium while the palmar aspect is made up of carpal bones. Our study aimed to see whether there were differences in carpal tunnel size between men and women. Material and methods The study was conducted on 65 healthy adults, 13 (20%) were males and 52 (80%) were females (both non-pregnant and pregnant). Inclusion criteria were healthy adults and bilaterally symmetrical limbs. Exclusion criteria were chronic disease, diabetes, hypertension, immunological disorders, any visible abnormalities, and a history of upper extremity pain on either side. A high-resolution ultrasound machine with a linear transducer was used to perform an ultrasound scan of the carpal tunnel. The anteroposterior dimension was measured at the midline, or along the axis of the middle finger, and the transverse diameter was measured at the midpoint of the flexor retinaculum. The cross-sectional area of the tunnel was measured at its largest diameter within the carpal tunnel. All the dimensions were measured in centimeters. Results The mean transverse diameter of the right side was 1.824 ± 0.223 cm (p-value 0.002) and of the left side was 1.742 ± 0.197 cm (p-value 0.004). The mean cross-sectional area of the carpal tunnel on the right side was 1.417 ± 0.379 cm2 (p-value 0.008) and on the left side was 1.306 ± 0.303 cm2 (p-value 0.004), respectively. Age, sex, weight, and BMI were discussed. The carpal tunnels of females were found to be comparatively squarer and smaller than those of males. Conclusion The transverse diameter and cross-sectional area of the carpal tunnel and their correlation with carpal tunnel syndrome are predicted by age, sex, weight, and BMI. Both sexes had the same wrist ratio.

External wrist ratio is not a proxy for internal carpal tunnel shape: Implications for evaluating carpal tunnel syndrome risk

Carpal tunnel syndrome (CTS) is highly prevalent, resulting in decreased function and increased need for costly healthcare services. External wrist ratio (depth/width >0.70) is a strong predictor of the development of CTS and has been suggested to be a proxy for internal carpal tunnel (CT) shape. Conversely, sonography can more directly evaluate CT shape. The purpose of our study was to explore the relationship between wrist ratio and sonographic CT measurements to (1) evaluate the reliability of sonographic CT measurements and (2) explore how external wrist measures relate to anthropometric features of the CT. We used sonographic imaging on a sample of healthy participants (n = 226) to measure CT cross-sectional area, depth, width, and depth/width ratio. We conducted exploratory correlation and regression analyses to identify relationships of these measures with external wrist ratio. Reliability for dominant and nondominant sonographic CT measures ranged from good to excellent (0.79-0.95). Despite a moderate correlation between CT width and depth and their external wrist counterparts (0.33-0.41, p < 0.001), wrist ratio and CT ratio demonstrated weak to no correlation (dominant: r = 0.12, p = 0.053; nondominant: r = 0.20, p = 0.002) and the mean CT ratio was far lower than the mean wrist ratio (0.45 vs. 0.71 bilaterally). Supporting this, we observed several key differences in the relationship between external wrist measures compared to corresponding CT measures. Additionally, regression analyses combining participant factors and CT measurements produced models accounting for less than 15% of the variability in external wrist ratio (linear models) or correctly predicting less than 68% of wrist ratio-based risk categorization (logistic models). Overall, among healthy young adults, wrist shape is not an adequate proxy for CT shape.

A literature review of carpal tunnel syndrome and its association with body mass index, wrist ratio, wrist to palm ratio, and shape index

STUDY DESIGN

Systematic literature review of case-controlled studies.

INTRODUCTION

Carpal tunnel syndrome (CTS) is one of the most common tubular neuropathies where certain anatomical variations may be accounted for as risk factors for CTS, including body mass index (BMI), wrist ratio (WR), wrist to palm ratio (WPR), shape index (SI), and digit length.

PURPOSE OF THE STUDY

To assess case-control studies examining the association between specific anatomical variations of the wrist as risk factors for developing CTS and whether this effect is the same for both genders.

METHODS

The literature search was conducted between February-June 2020 through PubMed, Cochrane Library, CINAHL Plus and PEDro. The literature search yielded 149 potential publications, fifteen of which were filtered in accordance with eligibility criteria. The methodological quality was assessed by using the Newcastle-Ottawa Quality Assessment Form for Case-Control Studies (NOS).

RESULTS

The total number of subjects included in this review was n=4299. The largest sample was n=1117 participants and the smallest n=54. All studies included patients who had a clinical diagnosis of CTS confirmed with nerve conduction studies and or ultrasonography. CTS was significantly higher in patients with higher BMI, WR, WPR compared to control groups. BMI and WR were the only indicators that can be considered as strong risk factors.

CONCLUSIONS

Discussion: Despite the general patterns on the association of BMI, WPR, WR and SI as risk factors for the development of CTS, there were exceptions to the accepted results and conclusions.

CONCLUSION

Clinicians are recommended to conduct more research to confirm anthropometric measurements as risk factors for the development of CTS, mainly SI and WPR. When determining the cut-off values for BMI and WR, it is recommended to take into account additional risk factors such as occupation.

How to Differentiate Pronator Syndrome from Carpal Tunnel Syndrome: A Comprehensive Clinical Comparison

The diagnostic process that allows pronator syndrome to be differentiated reliably from carpal tunnel syndrome remains a challenge for clinicians, as evidenced by the most common cause of pronator syndrome misdiagnosis: carpal tunnel syndrome. Pronator syndrome can be caused by compression of the median nerve as it passes through the anatomical structures of the forearm, while carpal tunnel syndrome refers to one particular topographic area within which compression occurs, the carpal tunnel. The present narrative review is a complex clinical comparison of the two syndromes with their anatomical backgrounds involving topographical relationships, morphology, clinical picture, differential diagnosis, and therapeutic options. It discusses the most frequently used diagnostic techniques and their correct interpretations. Its main goal is to provide an up-to-date picture of the current understanding of the disease processes and their etiologies, to establish an appropriate diagnosis, and introduce relevant treatment benefiting the patient.

Independent risk factors of carpal tunnel syndrome: Assessment of body mass index, hand, wrist and finger anthropometric measurements

BACKGROUND: The most prevalent neuropathy in the upper extremity is carpal tunnel syndrome (CTS). A variety of related risk factors such as biomechanical exposures, body mass index (BMI), sex and hand shape are reported to be related to CTS. OBJECTIVE: We aimed to identify the role of BMI, hand, wrist and finger anthropometric dimensions in the development of CTS, and to compare these measured variables between control and CTS participants. METHODS: A cross-sectional, case control study (n = 240, CTS = 120, controls = 120) with participants recruited from a convenience sample diagnosed with CTS and referred for anthropometric measurements. The control participants were matched by age and sex. The body height, weight, hand width, hand length, wrist depth, wrist width, wrist circumference, and finger length were measured. Hand, wrist and finger indices, hand to height ratio, and BMI were calculated. Mean values of all dimensions were compared between cases and controls, and the role of independent risk factors were determined by logistic regression analysis. RESULTS: The mean BMI, age, weight, sex and height were not significant between the two groups. Among the measured dimensions and calculated indices the significantly different variables between two groups were the wrist width, wrist depth, wrist circumference, hand index, hand to height index, and wrist index. Regression analysis showed that the wrist index (β=-1.7, p = 0.0001), wrist depth (β=0.25, p = 0.0001) and wrist width (β=0.21, p = 0.0001) were the strongest factors in CTS development in the sample. CONCLUSION: Wrist parameters have a strong role in predicting the development of CTS, while BMI was not confirmed as an independent risk factor.

Metabolic syndrome and anthropometric indices in CTS hands: an electrophysiological study

INTRODUCTION

This study aims to evaluate the effect of metabolic syndrome (MetS) and anthropometric indices on carpal tunnel syndrome (CTS).

METHODS

Forty-three healthy controls and 41 CTS patients were enrolled. Complaints of patients were assessed by Boston Questionnaire (BQ). MetS components were investigated. Wrist circumference, wrist depth, wrist width, palm width, and palm length were measured. Routine nerve conduction studies of median and ulnar nerves as well as the "sensitive" comparison tests were performed. Cutaneous silent period (CuSP) was studied by stimulating both second and fifth digital nerves while recording over thenar muscles.

RESULTS

The vast majority of the participants were female and right-handed. CTS was bilateral in 61% of patients. Data of 109 hands were analyzed. MetS was more frequent in CTS patients. BQ scores were not related to MetS. Waist circumference, serum TG, and fasting glucose levels were higher in CTS patients. CTS hands with MetS had lower median CMAP amplitudes and increased sensory thresholds. Sensory thresholds were increased with both median and ulnar nerve stimulations suggesting a wider spread of peripheral nerve excitability changes in MetS presence. CuSPs were recorded from all 109 hands. CuSP latencies and durations were similar between controls and CTS patients. Wrist ratio was the only anthropometric index that was a statistically significant predictor for CTS development.

CONCLUSION

MetS was more prevalent in CTS patients. Some clinical and electrophysiological features (mainly sensory thresholds) may worsen in presence of MetS, but not the wrist ratio.

Demographical, Anatomical, Disease-Related, and Occupational Risk Factors for Carpal Tunnel Syndrome

Background: Carpal tunnel syndrome (CTS) is the most common focal mononeuropathy. It causes characteristic symptoms, including numbness and paresthesia in hand due to median nerve compression at the wrist. Objectives: We aimed to investigate CTS prevalence and personal, psychosocial, biomedical, and occupational factors related to it comprehensively, according to scattered publications, without the simultaneous evaluation of all CTS risk factors. Methods: A total of 345 patients referred to a hand clinic with a complaint of paresthesia in upper extremities and suspected CTS. The patients underwent neurological assessment and electrodiagnostic (EDX) tests to confirm the diagnosis. The demographic information, past medical history, past trauma history, and occupational history of all the patients were recorded and finally analyzed with SPSS software. Results: Of the patients, 213 (67.1%) met the criteria for CTS, of whom 160 (75%) were female. Females were significantly more affected by CTS than males (P < 0.05). The mean age was higher in the CTS patients (53.80 ± 11.57 years) than in non-patients (42.39 ± 12.31 years, P < 0.001). No statistical relevance was found between CTS prevalence with occupational history, underlying medical conditions, positive Tinel’s and Phalen's tests, and muscle atrophy. Conclusions: We recognized age and gender as main determinants in developing CTS. We also found that older age was related to higher CTS intensity.

The relationship of serum lipid profiles and obesity with the severity of carpal tunnel syndrome

INTRODUCTION

Carpal tunnel syndrome (CTS) is a prominent compressive neuropathy. There are a number of risk factors for creating CTS but the effect of these factors on the severity of CTS is unclear. In this study, we aimed to assess the correlation of serum lipid profile and obesity with the severity of CTS.

METHODS

this cross-sectional study was conducted on 118 patients with idiopathic CTS. Blood samples were obtained for determining the serum levels of total cholesterol (TC), triglyceride (TG), low-density lipoprotein (LDL-C), and high-density lipoprotein (HDL-C) after 12 hours of overnight fasting. The participants were then divided into two groups of normal and abnormal serum lipids. Body mass index ≥ 30 kg/m2 was considered as obesity. The severity of CTS was determined based on the electrophysiological results and Boston CTS Questionnaire (BCTSQ) that evaluates symptoms severity (SSS) and functional status (FSS) of patients.

RESULTS

out of 118 participants, 108 patients performed lipid profile test that 41.17%, 50.42%, 25.21%, and 20.16% of them had TC ≥ 200, TG ≥ 150, LDL-C ≥ 130, and HDL-C < 60 milligrams per deciliter (mg/dl), respectively. The mean scores of SSS in patients with dyslipidemia including the high level of TC, TG, LDL-C, and low level of LDL-C were 34.59±7.86, 34.05±8.73, 34.93±8.21, and 33.48±7.56, respectively. There was no significant association between lipid profile and the symptom severity scale of CTS (p-value > 0.05). The mean BMI of participants was 31.35±5.35 kg/m2, and 58.5% of them had a BMI ≥ 30 kg/m2. The mean score of SSS and FSS was 33.18±8.24 and 24.43±7.12 in obese patients (BMI ≥ 30 kg/m2), and was 34.06±7.85 and 23.06±7.67 in patients with BMI < 30 kg/m2. We found no significant association between obesity with the SSS and FSS (p-value = 0.53 and 0.32, respectively). In terms of the relationship between electrophysiological grading with obesity, 44 (63.8%) of patients with BMI ≥ 30 kg/m2 and 22 (45.8%) patients with BMI < 30 kg/m2 had severe to extreme severe CTS. There was no significant association between obesity and the severity of CTS (p-value = 0.054).

CONCLUSION

the results of this study did not demonstrate an association between serum lipid profile and obesity with the severity of carpal tunnel syndrome. The findings of this study may not be extrapolated to other populations. Further studies with more samples are needed to investigate this association.

Do carpal Tunnel Hands Have Different Shape Compare to Normal Hands?

Background

Given the fact that the carpal tunnel syndrome (CTS) happens as a consequence of the median nerve entrapment, besides other known factors, the shape and anthropometric characteristics of the carpal tunnel, wrist, and hand could be considered as a predisposing risk factor for idiopathic CTS. The aim of this study was to evaluate the morphology and radiologic scales in CTS hands.

Methods

In this prospective study, patients who underwent upper extremity electrodiagnostic studies were enrolled for hand morphologic and radiographic indexes. Patients were divided into CTS suffering and CTS symptom-free groups according to nerve conduction velocity (NCV) findings. A true posteroanterior radiograph of the hands was pas performed for each participant. Metacarpal length to wrist length index (carpal ratio), metacarpal length to metacarpal width index, third to first metacarpal length, hand length index, and hand volume index were measured in both groups.

Results

Significant differences were seen between the two groups regarding the body mass index (P< 0.001), metacarpal length divided by metacarpal width index (P=0.08), first metacarpal length divided by third metacarpal length (P=0.002), wrist circumference divided by distal flexor wrist crease to the tip of the third finger (P< 0.001), distal flexor wrist crease to the tip of the third finger divided by hand volume (P=0.05), and distal flexor wrist crease to the tip of the third finger divided by wrist circumference (P< 0.001). Multivariable analysis of hand indices were statically significant for the first metacarpal length divided by third metacarpal length (P=0.00), wrist circumference divided by distal flexor wrist crease to the tip of the third finger (P=0.138), and distal flexor wrist crease to the tip of the third finger divided by wrist circumference (P=0.117). However, first metacarpal length divided by third metacarpal length and third metacarpal length divided by palm height were associated with higher CTS occurrences. Receiver operating characteristic curve analysis demonstrated cutoff points which were possible to estimate only for first metacarpal length divided by third metacarpal length and wrist circumference divided by distal flexor wrist crease to the tip of the third finger.

Conclusion

Based on our findings, CTS hand is characterized by shorter fingers compared to thumb and wrist (metacarpal length to wrist length and hand length indexes), wider (metacarpal length to metacarpal width index), and bulkier (hand volume index) compared to non-CTS hands. The severity of CTS was correlated with a higher carpal ratio. In conclusion, CTS hands are bulkier with wider palms and shorter fingers compared to thumb. In this study, the thumb to the third metacarpal length was proved to be the best index for diagnosis of "CTS hand".

The effect of social deprivation on the incidence rate of carpal and cubital tunnel syndrome surgery

We sought to establish whether carpal and cubital tunnel syndrome requiring surgery is associated with deprivation in England. Data from 10,496 adult patients who were treated in our hand unit over a 20-year period were reviewed. The Index of Multiple Deprivation was used to measure deprivation from the patients' postcode. The mean age at surgery in the most deprived three quintiles was significantly lower than in the least deprived two quintiles for carpal tunnel release (55 vs 59 years, respectively) and cubital tunnel release (52 vs 57 years, respectively). The incidence rate was significantly lower for the three least deprived quintiles when compared with the most deprived quintile for both conditions. The incidence rate ratio of the least deprived quintile compared with the most deprived quintile for carpal tunnel release was 0.70 for men and 0.76 for women. The incidence rate ratio of the least deprived quintile compared with the most deprived quintile for cubital tunnel release was 0.79 for men and 0.49 for women. Carpal tunnel and cubital tunnel syndrome requiring surgery is more common in deprived patients and occurs at an earlier age.Level of evidence: IV.

A Review of Carpal Tunnel Syndrome and Its Association with Age, Body Mass Index, Cardiovascular Risk Factors, Hand Dominance, and Sex

Carpal tunnel syndrome (CTS) is one of the most common compressive, canalicular neuropathies of the upper extremities, causing hand pain and impaired function. CTS results from compression or injury of the median nerve at the wrist within the confines of the carpal tunnel. Parameters such as age, sex, and body mass index (BMI) could be risk factors for CTS. This research work aimed to review the existing literature regarding the relationship between CTS and possible risk factors, such as age, sex, BMI, dominant hand, abdominal circumference, respiratory rate, blood pressure, and cardiac rate to determine which ones are the most influential, and therefore, take them into account in subsequent applied research in the manufacturing industry. We performed a literature search in the PubMed, EBSCO, and ScienceDirect databases using the following keywords: carpal tunnel syndrome AND (age OR sex OR BMI OR handedness OR abdominal circumference OR respiratory rate OR blood pressure OR cardiac rate). We chose 72 articles by analyzing the literature found based on selection criteria. We concluded that CTS is associated with age, female sex, and high BMI. Trends and future challenges have been proposed to delve into the relationship between risk factors and CTS, such as correlation studies on pain reduction, analysis of weight changes to predict the severity of this pathology, and its influence on clinical treatments.

Rates of Complications and Secondary Surgeries of Mini-Open Carpal Tunnel Release

Background: The purpose of this study was to determine the rates and types of complications and secondary surgeries after mini-open carpal tunnel release. Methods: A retrospective cohort study was performed for 1,328 patients who underwent mini-open carpal tunnel release from August 2008 to July 2013. Patients were excluded for acute trauma, the index procedure being revision surgery, neoplasm, age less than 18 years, incomplete records, and postoperative follow-up less than 1 month, which yielded 904 patients who underwent 1,144 surgeries. Results: Of 1,144 carpal tunnel releases performed, 14 (1.2%) were noted to have a complication at final follow-up, with no cases of major nerve or vessel injury. Fourteen patients (1.2%) underwent secondary surgery, including 11 cases for persistent or recurrent carpal tunnel syndrome and 3 cases for infection or hematoma. Chronic kidney disease was associated with an increased risk of complication. Diabetes mellitus, chronic kidney disease, and cervical radiculopathy were associated with an increased risk of secondary surgery. Conclusions: The short-term complication and secondary surgery rates of mini-open carpal tunnel release are low. Patients with diabetes mellitus, chronic kidney disease, and cervical radiculopathy should be counseled regarding risks of complication and secondary surgery.

Variations in Hook of Hamate Morphology: A Cadaveric Analysis

PURPOSE

The hook of the hamate is an anatomical structure that separates the ulnar border of the carpal tunnel from Guyon's canal and serves as a landmark for surgeons. The hook of the hamate is also subject to fracture from injury. We hypothesize that there are variations in the hook of the hamate in the general population.

METHODS

One thousand pairs of hamates (2,000 hamates) from the Hamann-Todd Collection at the Cleveland Natural History Museum were analyzed. The height of the hook of the hamate and the total height of the hamate bone were measured using digital calipers. The hook height ratio was defined as the hook height divided by the total height of the hamate. Statistical analysis was performed using unpaired Student's t test to determine differences in sex and race.

RESULTS

The mean hook height was 9.8 ± 1.4 mm (range, 2.5-15.9 mm), whereas the mean hook height ratio was 0.42 ± 0.04 (range, 0.15-0.56). There was a 3.1% (62/2,000) incidence of abnormally small hooks, which we classified as hypoplastic and aplastic. Of the hypoplastic hooks, 55% (24/44) were bilateral, whereas 44% (8/18) of the aplastic hooks were bilateral. The incidence of variation in size in the hook of the hamate was highest in white females (9.3%) and lowest in black males (1.4%).

CONCLUSIONS

Abnormalities in hook of hamate anatomy are common in the general population, especially in white females.

CLINICAL RELEVANCE

Knowledge of anatomic variation in the hook of the hamate may provide additional insight into surgeons' palpation of bony anatomy, interpretation of imaging studies, and use of the hook as a landmark during surgery.

Observed Differences between Males and Females in Surgically Treated Carpal Tunnel Syndrome Among Non-manual Workers: A Sensitivity Analysis of Findings from a Large Population Study

Objectives

We aimed at assessing whether differences among males and females in carpal tunnel syndrome (CTS) epidemiology might be attributable to segregation with respect to occupational biomechanical exposures or differential access to care by sex.

Methods

We analysed surgically treated cases of CTS occurring among non-manual workers in Tuscany between 1997 and 2000. We conducted a Monte Carlo simulation to estimate the difference in occupational biomechanical exposures between males and females necessary to explain the observed incidence rate ratios. We also accounted for the sex-specific probability of receiving surgery after the diagnosis of CTS, as women were reported to be more likely to undergo surgery in a subset of our study population. We quantified the hypothetical biomechanical overload through the hand activity level (HAL) metric proposed by the American Conference of Governmental Industrial Hygienists. To quantify the effect of HAL on CTS risk, we assumed a prior distribution based on findings from two large cohort studies of industrial workers.

Results

After adjustment for the probability of receiving surgery, women showed a 4-fold incidence of CTS as compared with men. To explain this association among non-manual workers, women should have an average value of HAL at least 5 points higher.

Conclusions

Our analysis does not support the hypothesis that the difference in CTS incidence between males and females is entirely attributable to occupational risk factors or to differential access to surgery. The causal pathway between sex and CTS might include more determinants such as hormonal factors, anthropometric characteristics, and non-occupational exposure to biomechanical overload (e.g. household tasks).

Effects of Anthropometric Measurements on Treatment Outcomes in Patients with Carpal Tunnel Syndrome

BACKGROUND

The purpose of this study was to investigate the relationship between anthropometric hand/wrist measurements and outcomes following static wrist splintage in patients with mild-to-moderate carpal tunnel syndrome (CTS).

METHODS

Thirty nine patients with mild-to-moderate CTS were enrolled in this study. Anthropometric measurements of hand and wrist including wrist width, wrist depth, palm length, hand length, wrist ratio (wrist depth/wrist width) and wrist/palm ratio (wrist depth/palm length) were recorded as well as body mass index and ultrasonographic cross sectional area of median nerve. Patients were treated with static wrist splints and evaluated at 2^nd, 4^th and 12^th weeks with Boston Carpal Tunnel Questionnaire, median nerve nerve conduction studies, Visual Analog Scale for pain and Likert Scale for numbness.

RESULTS

Following treatment with a static wrist splint, the wrist ratio was correlated significantly with improvements in Boston Functional Status Scale at the second and forth weeks (r = -0.354, p = 0.027 and r = -0.320, p = 0.050 respectively) and Visual Analog Scale at the forth and 12^th weeks (r = -0.352, p = 0.030 and r = -0.360, p = 0.029 respectively).

CONCLUSIONS

Splinting provides symptomatic improvement in mild-to-moderate CTS and this study suggests that the wrist anthropometric measurements may influence treatment outcomes.

High wrist ratio is a risk factor for carpal tunnel syndrome

Carpal tunnel syndrome (CTS) is the most common upper extremity entrapment neuropathy and various risk factors have been implicated in the etiology. In this study, we aimed to determine whether anthropometric measurements are independent risk factors for CTS. Patients with symptoms of CTS (n = 27) and asymptomatic controls (n = 27) were enrolled following electrophysiological confirmation. Body mass index (BMI) was recorded and anthropometric measurements of the hand were made by a digital caliper. BMI, wrist width, wrist depth, palm length, hand width, wrist ratio, wrist/palm ratio, and wrist/hand ratio were significantly higher in the CTS group. BMI, wrist ratio, wrist/palm ratio, and wrist/hand ratio were independent variables in the logistic regression analysis; wrist ratio was the only significant predictor of CTS. Patients with a wrist ratio higher than 0.69 were 8.2 times more likely to have CTS. This study suggests that wrist ratio may be considered as an independent risk factor for CTS. Clin. Anat. 31:698-701, 2018. © 2018 Wiley Periodicals, Inc.

Inter-Rater and Intra-Rater Reliability of Sonographic Median Nerve and Wrist Measurements

Background:

Electrophysiologic studies have been considered the “gold standard” in diagnosing carpal tunnel syndrome (CTS); however, reports of false-negative results, as well as discomfort for the patient during the procedure has paved the use of ultrasound, being a painless and cost-efficient tool, as an alternative means for its diagnosis. Various ultrasound parameters assessing the median nerve and wrist dimensions have been described, but description of landmarks to assess these in a reliable manner has been lacking.

Methodology:

A systematic search of different databases yielded data regarding ultrasound parameters for CTS diagnosis, the landmarks used, and presence of reliability testing. Based on this, three sonologists discussed the external and sonographic landmarks that will be used in measuring the median nerve measurements, bowing of the flexor retinaculum and the carpal tunnel dimensions. A pilot test with two consecutive healthy participants using the discussed ultrasound parameters was carried out, and results were subjected to inter- and intra-rater reliability testing. Modifications were accordingly made on the acquisition of ultrasound image using external landmarks. The reliability testing proper was done with ten consecutive healthy participants.

Results:

Based on the systematic review and the pilot study, external landmarks were used to locate the median nerve in the forearm, carpal tunnel inlet and outlet. For the forearm measurement, it was taken 10 cm proximal from the distal palmar crease. The distal palmar crease was the external landmark used for the carpal tunnel inlet, while for the carpal tunnel outlet; it was measured 1 cm distal to the distal palmar crease. Instead of using the inner edge of the hook of hamate and trapezium, the apices of these bones were used as the landmarks in measuring the carpal tunnel outlet dimensions. There was excellent intra-rater reliability (mid-forearm, carpal tunnel inlet and outlet) except for the following: cross-sectional area (CSA) of the median nerve at the carpal tunnel inlet and outlet; and bowing of the flexor retinaculum. All the parameters had an excellent inter-rater reliability measured at the three levels (intraclass correlation [ICC]: Of 0.77–0.99) except for CSA of the median nerve at the levels of the forearm (fair-to-good with ICC of 0.71) and the carpal tunnel inlet (fair-to-good reliability of ICC: 0.43).

Conclusion:

There was an improved inter- and intra-rater reliability when external landmarks were used instead of sonographic landmarks.

Comparing indices of median nerve among diabetic patients with or without metabolic syndrome

BACKGROUND

Metabolic syndrome is highly prevalent among patients with type II diabetes and is reported as a strong risk factor for cardiovascular diseases as well as carpal tunnel syndrome (CTS). The aim of the current study was to compare median nerve indices among diabetic patients with and without metabolic syndrome.

METHODS

This cross-sectional study was conducted on 105 patients with type II diabetes whom participated in the coronary artery disease risk factor study in Kerman, Iran (KERCARDS). Patients with type II diabetes were called and those with clinical symptoms of CTS were included in the study, and median nerve indices were measured according to standard electro diagnosis tests. GEE statistical model was used to compare median nerve indices among diabetic patients with and without metabolic syndrome. All statistical analysis was done using SPSS 20.0.

RESULTS

The mean age of participants was 57.57±9.53. There was no significant difference between the left and right hand regarding median nerve indices except median nerve motor amplitude (MA). Furthermore, components of metabolic syndrome including BMI and LDL were determined as risk factors for CTS according to several indices.

CONCLUSION

Components of metabolic syndrome had more influence on sensory indices than motor indices and primary control of these components might prevent dysfunction of sensory neurons and also motor neurons in advanced stages among diabetic patients.

Surgical Demographics of Carpal Tunnel Syndrome and Cubital Tunnel Syndrome Over 5 Years at a Single Institution

PURPOSE

Carpal tunnel and cubital tunnel syndrome are the 2 most common upper-limb compressive neuropathies. However, whether the characteristics of patient populations undergoing surgery for these conditions are similar is unclear in terms of demographics and concomitant pathologies. Our null hypothesis was that there are no identifiable differences between these patient populations.

METHODS

A retrospective cohort study was performed by billing system query using Common Procedural Terminology (CPT) codes for all patients who underwent open carpal tunnel release (CTR) (CPT code 64721) and/or open cubital tunnel surgery (CPT code 64718) by 1 of 4 hand surgeons from August 2008 to July 2013. Application of exclusion criteria of acute trauma, revision surgery, neoplasm, age less than 18 years, and inaccurate or insufficient records resulted in identification of 1,114 patients who underwent CTR, 264 patients who underwent cubital tunnel surgery, and 76 patients who underwent both. Computerized medical records were analyzed for demographic variables, medical comorbidities, and other procedures performed under the same anesthetic.

RESULTS

In the multivariable analysis, older age, female sex, higher body mass index, trigger finger, and de Quervain tenosynovitis were associated with CTR. Prior trauma to the anatomic site was more common in the cubital tunnel group. Diabetes mellitus was associated with patients who had both procedures.

CONCLUSIONS

The populations of patients who undergo surgery for different upper-extremity compressive neuropathies are not homogenous: CTR is associated with older age, female sex, higher body mass index, and hand tendinopathies. Cubital tunnel decompression is associated with prior trauma to the anatomic site. Diabetic patients are more likely to have both procedures. Diabetic patients undergoing either procedure should be evaluated for other peripheral nerve compression pathologies.

TYPE OF STUDY/LEVEL OF EVIDENCE

Diagnostic IV.

Association between wrist ratio and carpal tunnel syndrome: Effect modification by body mass index

INTRODUCTION

Previous studies have reported higher wrist ratios (WR) related to carpal tunnel syndrome (CTS) but have not assessed effect modification by obesity and may have inadequately controlled for confounders.

METHODS

Baseline data of a multicenter prospective cohort study were analyzed. CTS was defined by nerve conduction study (NCS) criteria and symptoms.

RESULTS

Among the 1,206 participants, a square-shaped wrist was associated with CTS after controlling for confounders (prevalence ratio = 2.27; 95% confidence interval [95% CI], 1.33-3.86). Body mass index (BMI) was a strong effect modifier on the relationship between WR and both CTS and abnormal NCS results, with normal weight strata of rectangular versus square wrists = 8.18 (95% CI, 1.63-49.96) and 7.12 (95% CI, 2.19-23.16), respectively.

DISCUSSION

A square wrist is significantly associated with CTS after controlling for confounders. Effect modification by high BMI masked the eightfold magnitude adjusted relationship seen between WR and CTS among normal weight participants. Muscle Nerve 56: 1047-1053, 2017.

Carpal tunnel syndrome: Investigating the sensitivity of initial-diagnosis with electro-diagnostic tests in 600 cases and associated risk factors especially manual milking

BACKGROUND

Electro-diagnostic studies are the most reliable methods in diagnosis of carpal tunnel syndrome (CTS). Although there are many risk factors associated with CTS, there are a limited number of studies in the literature indicating that manual milking, which is frequently seen in Turkey, is a risk factor for CTS.

OBJECTIVE

The purpose of this study was to evaluate demographic findings of cases referred due to initial diagnosis of CTS as well as aetiological data especially manual milking and to investigate the sensitivity of initial diagnosis of CTS.

METHODS

Six hundred patients, who were referred to our electromyography laboratory due to initial diagnosis of CTS, were included. Demographic findings, duration of complaints, existence of diabetes mellitus, and manual milking histories of all patients were recorded. Sensitivity of initial diagnosis was investigated based on electro-diagnostic test results.

RESULTS

According to electro-diagnostic test results, 289 of the patients were diagnosed with CTS (48.17%). 110 (18.3%) of 600 patients had a history of manual milking. In 94 of this group (85.4%), CTS was detected. Statistically significant correlation was found between CTS and age, female gender, duration of complaints, obesity and manual milking.

CONCLUSIONS

This study confirms that manual milking is an important risk factor for CTS in addition to female gender, age, symptom duration and obesity. The fact that sensitivity of initial diagnosis of CTS was found to be low according to electro-diagnostic test results indicates importance of detailed clinical evaluation.

Outcomes and Satisfaction with Endoscopic Carpal Tunnel Releases and the Predictors - A Retrospective Cohort Study

Background:

Patient’s final satisfaction with endoscopic carpal tunnel release (ECTR) is still unpredictable. The study aims to find the predictive factors for satisfaction in patients with carpal tunnel syndrome (CTS) treated by ECTR using the Boston CTS questionnaire.

Methods:

We conducted a retrospective chart review of 37 patients (55 hands) who received ECTR and completed Boston carpal tunnel questionnaire at preoperative visit, 1 month and 6 months after operation while a telephone interview was conducted at 2 years after operation. Independent risk variables, including mean symptom severity scale, functional status scale, each item in questionnaire at all the time points, ASA physical status scale, age, gender, dominant site lesion, bilateral lesions, duration of symptoms and anesthesia method were recorded. Final outcome was determined by the patient’s satisfaction at the interval of 2 years. Predictors to outcome were analyzed by stepwise multiple regression analysis and tested with Pearson correlation test. A p value of less than 0.05 was considered significant.

Results:

The severity of hand or wrist numbness during the daytime (Q6, explained 6.5% variances), the severity of numbness or tingling at night (Q9, explained 16.2% variances), the functional status of writing (q1, explained 13.9% variances), carrying grocery bags (q7, explained 13.6% variances) had significant predictive value (p<0.001). Other factors were not significant in the analysis including ASA, gender, age, dominant site lesion, bilateral lesions, anesthesia method and duration of symptoms.

Conclusions:

Boston questionnaire is a simple and reliable tool with high predictive values to evaluate patient’s outcome and satisfaction in ECTR.

Multifocal Neuropathy: Expanding the Scope of Double Crush Syndrome

Double crush syndrome (DCS), as it is classically defined, is a clinical condition composed of neurological dysfunction due to compressive pathology at multiple sites along a single peripheral nerve. The traditional definition of DCS is narrow in scope because many systemic pathologic processes, such as diabetes mellitus, drug-induced neuropathy, vascular disease and autoimmune neuronal damage, can have deleterious effects on nerve function. Multifocal neuropathy is a more appropriate term describing the multiple etiologies (including compressive lesions) that may synergistically contribute to nerve dysfunction and clinical symptoms. This paper examines the history of DCS and multifocal neuropathy, including the epidemiology and pathophysiology in addition to principles of evaluation and management.

Severity of Carpal Tunnel Syndrome and Diagnostic Accuracy of Hand and Body Anthropometric Measures

Objective

To study the diagnostic properties of hand/wrist and body measures according to validated clinical and electrophysiological carpal tunnel syndrome (CTS) severity scales.

Methods

We performed a prospective case-control study. For each case, two controls were enrolled. Two five-stage clinical and electrophysiological scales were used to evaluate CTS severity. Anthropometric measurements were collected and obesity indicators and hand/wrist ratios were calculated. Area under the receiver operating characteristic curves (AUC), sensitivity, specificity, and likelihood ratios were calculated separately by gender.

Results

We consecutively enrolled 370 cases and 747 controls. The wrist-palm ratio, waist-hip-height ratio and waist-stature ratio showed the highest proportion of cases with abnormal values in the severe stages of CTS for clinical and electrophysiological severity scales in both genders. Accuracy tended to increase with CTS severity for females and males. In severe stage, most of the indexes presented moderate accuracy in both genders. Among subjects with severe CTS, the wrist-palm ratio presented the highest AUC for hand measures in the clinical and electrophysiological severity scales both in females (AUC 0.83 and 0.76, respectively) and males (AUC 0.91 and 0.82, respectively). Among subjects with severe CTS, the waist-stature ratio showed the highest AUC for body measures in the clinical and electrophysiological severity scales both in females (AUC 0.78 and 0.77, respectively) and males (AUC 0.84 and 0.76, respectively). The results of waist-hip-height ratio AUC were similar.

Conclusions

Wrist-palm ratio, waist-hip-height ratio and waist-stature ratio could contribute to support the diagnostic hypothesis of severe CTS that however has to be confirmed by nerve conduction study.

Development of Kinematic Graphs of Median Nerve during Active Finger Motion: Implications of Smartphone Use

Background

Certain hand activities cause deformation and displacement of the median nerve at the carpal tunnel due to the gliding motion of tendons surrounding it. As smartphone usage escalates, this raises the public’s concern whether hand activities while using smartphones can lead to median nerve problems.

Objective

The aims of this study were to 1) develop kinematic graphs and 2) investigate the associated deformation and rotational information of median nerve in the carpal tunnel during hand activities.

Methods

Dominant wrists of 30 young adults were examined with ultrasonography by placing a transducer transversely on their wrist crease. Ultrasound video clips were recorded when the subject performing 1) thumb opposition with the wrist in neutral position, 2) thumb opposition with the wrist in ulnar deviation and 3) pinch grip with the wrist in neutral position. Six still images that were separated by 0.2-second intervals were then captured from the ultrasound video for the determination of 1) cross-sectional area (CSA), 2) flattening ratio (FR), 3) rotational displacement (RD) and 4) translational displacement (TD) of median nerve in the carpal tunnel, and these collected information of deformation, rotational and displacement of median nerve were compared between 1) two successive time points during a single hand activity and 2) different hand motions at the same time point. Finally, kinematic graphs were constructed to demonstrate the mobility of median nerve during different hand activities.

Results

Performing different hand activities during this study led to a gradual reduction in CSA of the median nerve, with thumb opposition together with the wrist in ulnar deviation causing the greatest extent of deformation of the median nerve. Thumb opposition with the wrist in ulnar deviation also led to the largest extent of TD when compared to the other two hand activities of this study. Kinematic graphs showed that the motion pathways of median nerve during different hand activities were complex.

Conclusion

We observed that the median nerve in the carpal tunnel was rotated, deformed and displaced during the hand activities that people may be performed when using a smartphone, suggesting an increased risk of carpal tunnel syndrome (CTS). In addition, the kinematic graphs of median nerve developed in the present study provide new clues for further studies on the pathophysiology of CTS, and alerting smartphone users to establish proper postural habits when using handheld electronic devices.

Determination of the longitudinal median nerve mobility in different neurodynamic techniques

Background

Neurodynamic techniques which include tensioning and gliding techniques are being employed in the treatment of carpal tunnel syndrome. There are few in vivo studies that have assessed the longitudinal mobility of the nerve using these techniques. The objective of this study was to determine the longitudinal excursion of the median nerve at the level of the wrist and distal arm by having the cervical spine lateral flexion or the wrist extension as terminal movement.

Method

Twenty healthy participants were included in the study. Techniques 1 and 2 had wrist extension as its terminal movement while techniques 3 and 4 had ipsilateral and contralateral neck lateral flexion as its terminal motion. Median nerve longitudinal excursion was determined using dynamic ultrasound and was measured by a motion tracking analysis program employing a fast template tracking method.

Results

Regardless of neurodynamic techniques, longitudinal mobility is highest at the wrist and arm level if the terminal movement is wrist extension. Median nerve excursion at the wrist and arm levels is 15.53 ± 7.04 mm and 6.82 ± 2.97 mm for technique 1 and 13.43 ± 5.64 and 5.33 ± 2.37 mm for technique 2, respectively. There was a significant decrease in median nerve excursion at the wrist level when the terminal movement was at the cervical spine.

Conclusion

The largest median nerve excursion in the arm and wrist occurred when wrist extension is the terminal movement. Contralateral cervical lateral flexion with a prepositioned extended wrist produced the least motion of the median nerve at both sites.

Anthropometric measurements as a screening test for carpal tunnel syndrome: receiver operating characteristic curves and accuracy

OBJECTIVE

To identify optimal cutoff values for body, hand, and wrist measurements in order to correctly identify individuals with carpal tunnel syndrome (CTS), using receiver operating characteristic (ROC) curves.

METHODS

We enrolled patients with CTS and control subjects at a 1:2 ratio, regardless of age and sex. The diagnosis of CTS was based on clinical findings and delayed distal conduction velocity of the median nerve. The anthropometric measurements included weight, height, waist circumference, hip circumferences, wrist depth/width, third digit length, and palm length/width. Obesity indicators and hand/wrist ratios were calculated. Area under the ROC curve (AUC), sensitivity, specificity, and likelihood ratios were calculated separately according to sex. To assess the role of multiple anthropometric measurements, we fit multivariable logistic regression models including age, wrist ratio, shape index, body mass index, and waist-to-hip ratio.

RESULTS

The study group comprised 1,117 subjects (250 female patients and 474 female controls; 120 male patients and 273 male controls). In women, the accuracy of all anthropometric measures was low (AUC ≤0.64). In men, the accuracy of the hand ratio, shape index, and wrist-to-palm ratio was moderate (AUC = 0.75). The estimates from the multivariable models confirmed the well-known associations between the selected variables and the risk of CTS, but the use of multiple predictors did not dramatically improve the diagnostic performance observed for single anthropometric indexes.

CONCLUSION

In clinical practice, the cutoff values for many anthropometric measurements have limited value as tools for the diagnosis of CTS.

Ultrasound evaluation on carpal tunnel syndrome before and after bariatric surgery

OBJECTIVE

To evaluate the prevalence of carpal tunnel syndrome in candidates for bariatric surgery comparing with the non-obese population and verify the effects on it of bariatric treatment.

METHODS

We studied three groups of individuals: 1) patients waiting for bariatric surgery (preoperative); 2) individuals who had already undergone the procedure (postoperative); and 3) control group. We collected demographic and clinical data of carpal tunnel syndrome. The Ultrasound examination was carried out to diagnose the syndrome by measuring the median nerve area.

RESULTS

We included 329 individuals (114 in the preoperative group, 90 in the postoperative group and 125 controls). There was a higher prevalence of paresthesias (p=0.0003), clinical tests (p=0.0083) on the preoperative group when compared with controls (p<0.00001). There were lowe levels of paresthesias (p=0.0002) and median nerve area (p=0.04) in postoperative patients but with no significant difference in general. A significant difference was found between the preoperative and postoperative groups (p=0.05) in those who performed non-manual work.

CONCLUSION

There was a higher prevalence of carpal tunnel syndrome in the preoperative group compared with the control one, but no significant difference was observed between the pre and postoperative groups in general. There was difference between pre and postoperative groups for non-manual workers.

Outcome of carpal tunnel release--correlation with wrist and wrist-palm anthropomorphic measurements

Wrist and wrist-palm measurements have been associated with the diagnosis of carpal tunnel syndrome. We found no reported study about how this correlation affects the outcome after surgery. We investigated the role of the measurements in predicting outcome after open carpal tunnel release. A total of 131 patients (88 female, 43 male) responded to our postal questionnaire using the Boston Carpal Tunnel assessment (65% response rate) at a minimum of 9 months post-operatively. Symptom and functional scores showed a strong correlation. There was no statistical difference in the outcome between wrist ratio (≥0.7 vs <0.7), wrist-palm ratio (≥0.41 vs <0.41) and gender, but a better functional score was very weakly correlated with a higher wrist ratio. A very large study would be needed to show any statistical correlation between both measurement and outcome.

The deformation and longitudinal excursion of median nerve during digits movement and wrist extension

The use of electronic devices, such as mobile phones and computers, has increased drastically among the young generation, but the potential health effects of carpal tunnel syndrome (CTS) on university students has not been comprehensively examined. Thirty-one university students aged 18 to 25 y with no symptoms of CTS were successfully recruited in this study. By using noninvasive ultrasonography, the morphological characteristics of the median nerve of each volunteer, and the extent of its longitudinal excursion movement under experimental conditions, in which a real operating environment of electronic devices was simulated, were quantified. The results demonstrated that the median nerve at the carpal tunnel inlet was flattened during wrist extension: the flattening ratio increased from 3.40 ± 0.91 at the neutral position to 4.10 ± 1.11 at the angle of 30° and 4.09 ± 1.11 at the angle of 45°. In addition, the median nerve became swollen after the students performed rapid mobile-phone keying for 5 min, indicated by a significant increase in the cross-sectional area from 6.05 ± 0.97 mm(2) to 7.56 ± 1.39 mm(2). Passive longitudinal excursion was observed at the median nerve when the students performed mouse-clicking (2.4 ± 1.0 mm) and mobile-phone keying tasks (1.7 ± 0.6 mm), with the mouse-clicking task generating a greater extent of longitudinal excursion than the mobile-phone keying task did. In conclusion, the findings of the present study verify the potential harm caused by using electronic devices while maintaining an inappropriate wrist posture for a substantial period.

Waist circumference and waist-to-hip ratio in carpal tunnel syndrome: a case-control study

BACKGROUND

The association between carpal tunnel syndrome (CTS) and high body mass index (BMI) and some hand measures is well known. No study has been specifically focused on waist circumference (WC) and waist-to-hip-ratio (WHR). The aim of this prospective case-control study is to evaluate the association between CTS and WC, WHR and other body and hand anthropometric measures.

METHODS

We consecutively enrolled one "idiopathic" CTS case for two controls in 3 outpatient electromyography labs. The main anthropometric measures were BMI, WC, WHR, wrist ratio (WR) and hand ratio (HR). We performed univariate and multivariate analyses.

RESULTS

Female cases and controls were 250 and 474 and male cases and controls were 120 and 273, respectively. At univariate analysis there were differences in many anthropometric measures between cases and controls. At multivariate logistic regression analyses high BMI, WC and WHR and abnormal HR and WR were independent risk factors for CTS. Crossing two categories between BMI, WC and WHR, the overweight subjects, especially females, were at risk only if they had very high WC or high WHR. The risk increased if they were obese.

CONCLUSIONS

High WC/WHR doubles the risk of CTS, the risk further increased if overweight/obese subjects have also very high WC or high WHR. The obese subjects were always at risk regardless of WC and WHR values. Metabolic causes of this association with CTS were hypothesised. BMI is not the only and most powerful body predictor of "idiopathic" CTS, but also WHR and WC should be considered. These measures may not be interchangeable and it may be desirable to consider the utility of their joint use.

Relationship of age, body mass index, wrist and waist circumferences to carpal tunnel syndrome severity

Carpal tunnel syndrome (CTS) has a multifactorial etiology involving systemic, anatomical, idiopathic, and ergonomic characteristics. In this study, an investigation of the relationship between the CTS degree established by electrophysiological measurements in patients with clinical CTS prediagnosis, and age, gender, body mass index (BMI), hand wrist circumference, and waist circumference measurements has been done. On 547 patients included in the study, motor and sensory conduction examinations of the median and ulnar nerve were done on one or two upper extremities thought to have CTS. In terms of CTS severity, the patients were divided into four groups (normal, mild, medium, and severe CTS). A total of 843 electrophysiological examinations were done consisting of 424 on the right hand wrist and 419 on the left hand wrist. When the age group of 18–35 years is taken as the reference group, the CTS development risk independent of BMI has been found to have increased by a factor of 1.86 for ages 36–64 years, and by 4.17 for ages 65 years and higher after adjustment for BMI. With respect to normal degree CTS group, the BMI were significantly different in groups with mild, medium, and severe CTS. The waist circumferences of groups with mild, medium, and severe CTS severity were found to be significantly higher in comparison to the normal reference group. When this value was corrected with BMI and re-examined the statistically significant differences persisted. The study identified a significant relationship between the CTS severity and age, BMI, waist circumference.

Importance of tissue morphology relative to patient reports of symptoms and functional limitations resulting from median nerve pathology

Significant data exist for the personal, environmental, and occupational risk factors for carpal tunnel syndrome. Few data, however, explain the interrelationship of tissue morphology to these factors among patients with clinical presentation of median nerve pathology. Therefore, our primary objective was to examine the relationship of various risk factors that may be predictive of subjective reports of symptoms or functional deficits accounting for median nerve morphology. Using diagnostic ultrasonography, we observed real-time median nerve morphology among 88 participants with varying reports of symptoms or functional limitations resulting from median nerve pathology. Body mass index, educational level, and nerve morphology were the primary predictive factors. Monitoring median nerve morphology with ultrasonography may provide valuable information for clinicians treating patients with symptoms of median nerve pathology. Sonographic measurements may be a useful clinical tool for improving treatment planning and provision, documenting patient status, or measuring clinical outcomes of prevention and rehabilitation interventions.

Conceptual heuristic models of the interrelationships between obesity and the occupational environment

OBJECTIVE

Research and interventions targeting the relationship between work, its attendant occupational hazards, and obesity are evolving but merit further consideration in the public health arena. In this discussion paper, conceptual heuristic models are described examining the role of obesity as both a risk factor and health outcome in the occupational setting.

METHODS

PubMed was searched using specific criteria from 2000 and onwards for evidence to support conceptual models in which obesity serves as a risk factor for occupational disease or an outcome of occupational exposures. Nine models are presented: four where obesity is a risk factor and five where it is an adverse effect.

RESULTS

A broad range of work-related health effects are associated with obesity including musculoskeletal disorders, asthma, liver disease, and cardiovascular disease, among others. Obesity can be associated with occupational hazards such as shift work, sedentary work, job stress, and exposure to some chemicals.

CONCLUSION

Identification of combinations of risk factors pertinent to obesity in the occupational environment will provide important guidance for research and prevention.

The effect of aging on muscle activation and postural control pattern for young and older computer users

A lot of older adults try to learn to use computers and might use different ways to perform a computer task compared to younger people. Fifteen healthy young and 15 healthy older adults participated in this study and all performed a series of mouse tasks. A three dimensional motion capture system and electromyographic analysis were used to obtain kinematic and kinetic data during performing the computer tasks. Three-way analysis of variance with repeated measures on task and time factors was used to analyze all dependent measurements. Older adults had higher RMS of forearm muscles compared to the young adults. The RMS of the finger extensor was highest when performing a dragging task. Compared with young adults, the older adults had greater cranial-cervical angle and neck flexion, but smaller head flexion, shoulder angle, elbow angle and ulnar deviation. Consequently, the older adults might have a greater risk of developing musculoskeletal disorder.

Carpal tunnel syndrome: the role of occupational factors among 906 workers

Background

Carpal tunnel syndrome (CTS) is common in the industrial setting. However,there is a controversy about the sole role of occupational ergonomic hazards in CTS.

Objectives

This study was conducted among assembling workers of a detergent factory and computer users with the aims of A) determination of CTS prevalence and B) evaluation of personal risk factors and level of exposure to occupational risk factors via Quick Exposure Check (QEC).

Materials and Methods

In this descriptive cross-sectional study, 906 cases (332 assembling workers and 574 computer workers) were enrolled. CTS was assessed by symptoms on the Katz hand diagram and physical examination. QEC technique was applied to evaluate physical exposure to the risk factors.

Results

According to this study, the prevalence of probable CTS was 14% in men and 8.9% in women; the rate of probable CTS was significantly higher in assembly workers than in computer users (P < 0.001). Mean age and work duration in the probable CTS group was statistically higher than in non-CTS group. But both groups were in the same range (fewer than 30, P = 0.024, 0.004); BMI in the probable CTS group was slightly lower than in non CTS group, but BMI in both groups were in the normal range. Wrist ratio > 0.7 correlated with increased risk of probable CTS (P < 0.001) Prevalence of probable CTS was significantly higher in third and fourth levels of QEC (P < 0.001).

Conclusions

Although this article had limitations, our findings suggest that the level of occupational exposure is an indicator of CTS development.

The WISTAH hand study: a prospective cohort study of distal upper extremity musculoskeletal disorders

Background

Few prospective cohort studies of distal upper extremity musculoskeletal disorders have been performed. Past studies have provided somewhat conflicting evidence for occupational risk factors and have largely reported data without adjustments for many personal and psychosocial factors.

Methods/design

A multi-center prospective cohort study was incepted to quantify risk factors for distal upper extremity musculoskeletal disorders and potentially develop improved methods for analyzing jobs. Disorders to analyze included carpal tunnel syndrome, lateral epicondylalgia, medial epicondylalgia, trigger digit, deQuervain’s stenosing tenosynovitis and other tendinoses. Workers have thus far been enrolled from 17 different employment settings in 3 diverse US states and performed widely varying work. At baseline, workers undergo laptop administered questionnaires, structured interviews, two standardized physical examinations and nerve conduction studies to ascertain demographic, medical history, psychosocial factors and current musculoskeletal disorders. All workers’ jobs are individually measured for physical factors and are videotaped. Workers are followed monthly for the development of musculoskeletal disorders. Repeat nerve conduction studies are performed for those with symptoms of tingling and numbness in the prior six months. Changes in jobs necessitate re-measure and re-videotaping of job physical factors. Case definitions have been established. Point prevalence of carpal tunnel syndrome is a combination of paraesthesias in at least two median nerve-served digits plus an abnormal nerve conduction study at baseline. The lifetime cumulative incidence of carpal tunnel syndrome will also include those with a past history of carpal tunnel syndrome. Incident cases will exclude those with either a past history or prevalent cases at baseline. Statistical methods planned include survival analyses and logistic regression.

Discussion

A prospective cohort study of distal upper extremity musculoskeletal disorders is underway and has successfully enrolled over 1,000 workers to date.

The Strain Index (SI) and Threshold Limit Value (TLV) for Hand Activity Level (HAL): risk of carpal tunnel syndrome (CTS) in a prospective cohort

A cohort of 536 workers was enrolled from 10 diverse manufacturing facilities and was followed monthly for six years. Job physical exposures were individually measured. Worker demographics, medical history, psychosocial factors, current musculoskeletal disorders (MSDs) and nerve conduction studies (NCS) were obtained. Point and lifetime prevalence of carpal tunnel syndrome (CTS) at baseline (symptoms + abnormal NCS) were 10.3% and 19.8%. During follow-up, there were 35 new CTS cases (left, right or both hands). Factors predicting development of CTS included: job physical exposure (American conference of governmental industrial hygienists Threshold Limit Value (ACGIH TLV) for Hand Activity Level (HAL) and the Strain Index (SI)), age, BMI, other MSDs, inflammatory arthritis, gardening outside of work and feelings of depression. In the adjusted models, the TLV for HAL and the SI were both significant per unit increase in exposure with hazard ratios (HR) increasing up to a maximum of 5.4 (p = 0.05) and 5.3 (p = 0.03), respectively; however, similar to other reports, both suggested lower risk at higher exposures. Data suggest that the TLV for HAL and the SI are useful metrics for estimating exposure to biomechanical stressors.

PRACTITIONER SUMMARY

This study was conducted to determine how well the TLV for HAL and the SI predict risk of CTS using a prospective cohort design with survival analysis. Both the TLV for HAL and the SI were found to predict risk of CTS when adjusted for relevant covariates.