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Research Article  |   January 2013
Importance of Tissue Morphology Relative to Patient Reports of Symptoms and Functional Limitations Resulting From Median Nerve Pathology
Author Affiliations
  • Shawn C. Roll, PhD, OTR/L, CWCE, is Assistant Professor, Division of Occupational Science and Occupational Therapy, University of Southern California, 1540 Alcazar Street, CHP 133, Los Angeles, CA 90089-9003; sroll@usc.edu. At the time of the study, he was Doctoral Candidate, The Ohio State University, Columbus
  • Kevin D. Evans, PhD, RT(R)(M)(BD), RDMS, RVS, FSDMS, is Associate Professor and Chair, Radiologic Sciences and Respiratory Therapy, The Ohio State University, Columbus
  • Xiaobai Li, PhD, is Biostatistical Scientist, Center for Biostatistics, The Ohio State University, Columbus
  • Carolyn M. Sommerich, PhD, is Associate Professor, Department of Integrated Systems Engineering, The Ohio State University, Columbus
  • Jane Case-Smith, EdD, is Professor and Chair, Occupational Therapy Division, The Ohio State University, Columbus
Article Information
Hand and Upper Extremity / Musculoskeletal Impairments / Work and Industry / Rehabilitation, Disability, and Participation
Research Article   |   January 2013
Importance of Tissue Morphology Relative to Patient Reports of Symptoms and Functional Limitations Resulting From Median Nerve Pathology
American Journal of Occupational Therapy, January/February 2013, Vol. 67, 64-72. doi:10.5014/ajot.2013.005785
American Journal of Occupational Therapy, January/February 2013, Vol. 67, 64-72. doi:10.5014/ajot.2013.005785
Abstract

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.

Carpal tunnel syndrome (CTS), the most frequently occurring of all compression neuropathies, primarily occurs as a result of compression of the median nerve in the carpal tunnel, which eventually leads to sensorimotor and occupational performance deficits. Significant research has investigated physical, occupational exposure, and personal factors related to CTS, and limited research has investigated the impact of psychosocial risk factors. However, little research has evaluated how these factors relate to the physiological status of the median nerve among people with varying levels of symptomatology.
Hazardous occupational exposures, such as vibration, direct compression, and prolonged highly repetitive and forceful hand–wrist tasks, are the most common risk factors researched for CTS (Barr, Barbe, & Clark, 2004; Bongers, Ijmker, van den Heuvel, & Blatter, 2006). Additionally, evidence has indicated that increased compression of the median nerve occurs as a result of various wrist positions (Viikari-Juntura & Silverstein, 1999). Forearm pronation and supination increase pressure in the carpal tunnel (Rempel, Bach, Gordon, & So, 1998), wrist flexion and extension can reduce the area within the carpal tunnel (Skie, Zeiss, Ebraheim, & Jackson, 1990), and prolonged or repetitive ulnar deviation of the wrist causes lateral compression of the median nerve (Hägg, Oster, & Byström, 1997). Of all positions, the anterior movement of the large flexor tendons during wrist flexion, combined with decreased space in the canal, creates the greatest compression of the median nerve (Keir, 2001).
Gender and anthropometry are two personal factors with the highest association with CTS (Feuerstein, Shaw, Nicholas, & Huang, 2004; Huang, Feuerstein, & Sauter, 2002). The prevalence of musculoskeletal disorders is 2–4 times higher among women (Lundberg, 2002; Park, Krebs, & Mirer, 1996), and women are significantly more likely to develop symptoms in the hand and wrist (Hagberg, Vilhemsson, Tornqvist, & Toomingas, 2007). Secondary to gender, wrist ratio (anterioposterior depth divided by mediolateral width) is one of the primary factors with a strong relationship to CTS (Gordon, Johnson, Gatens, & Ashton, 1988; Kamolz et al., 2004; Radecki, 1994). Among people with CTS, >75% have a square-shaped wrist (ratio >0.70; Radecki, 1994), and as the ratio increases (>0.75), so does the association with CTS (Lim, Tan, & Ahmad, 2008).
Despite the extent of hazardous occupational exposures and contributory personal factors, an increase in exposure to psychological stressors in the environment can be related to musculoskeletal symptoms (Devereux, Vlachonikolis, & Buckle, 2002). Negative psychological stress is correlated with a significant increase in motor unit activation in muscles of the upper extremity (Rissén, Melin, Sandsjö, Dohns, & Lundberg, 2000), and psychological demands of a job and the ability to control work tasks have been linked to changes in health (Bongers, Kremer, & ter Laak, 2002). Additionally, increased psychological strain can have a fundamental impact on quality of life and health across various occupations (Brisson et al., 1999; Edimansyah, Rusli, Naing, Mohamed Rusli, & Winn, 2007; Kawakami, Kobayashi, Araki, Haratani, & Furui, 1995).
Physiological changes in the median nerve leading to increased incidence of CTS are likely the result of a combination of occupational, personal, and environmental factors. Although a plethora of researchers have evaluated the predictive relationship of various personal and physical exposures to subjective symptoms (Farmer & Davis, 2008; Mattioli et al., 2009; Moghtaderi, Izadi, & Sharafadinzadeh, 2005; Sharifi-Mollayousefi et al., 2008), no studies have commented on the relationship of risk factors to median nerve morphology as predictors of these subjective reports.
Diagnostic ultrasonography is an accepted tool for observing median nerve morphology for diagnosis of CTS (Roll, Case-Smith, & Evans, 2011), and ultrasonography may be a valuable screening tool to identify median nerve pathology in an acute stage (Roll, Evans, Li, Freimer, & Sommerich, 2011). Ultrasonography is a pain-free, relatively inexpensive, and portable technology that can provide real-time images of tissues under the skin. Using ultrasonography, the size, shape, and overall appearance of the median nerve can be visualized, documented, and measured. Sonographic measurements are correlated to subjective symptoms of median nerve pathology (Kaymak et al., 2008), and these measures provide a method for documenting outcomes after carpal tunnel release (Mondelli, Filippou, Aretini, Frediani, & Reale, 2008). No studies have investigated the relationship of acute median nerve morphology to various risk factors, nor has it been investigated as an outcome measure for conservative treatments.
Successful prevention and rehabilitation techniques for median nerve pathology require an understanding of the acute physiology of the median nerve. The objectives of this research were to identify risk factors that may be predictive of subjective reports of symptoms or functional deficits and to determine the utility of including a measurement of morphology when planning or providing interventions for median nerve pathology. Our primary research question was, What is the relationship between current evidence-based risk factors for CTS and innovative measures of median nerve morphology, using gray-scale diagnostic ultrasonography, among people with varying symptomatology?
Method
The biomedical institutional review board of The Ohio State University approved the protocol, and all participants provided signed consent to participate.
Participants
The study sample was heterogeneous, maximizing the distribution and variability of data for an exploratory regression analysis. The sample included patients referred to a neurology clinic for evaluation of median nerve pathology and participants from a convenience population of nonpatient working adults. To be included, participants had to be of working age (18–65 yr old). Before consent, history of fracture or surgery in the dominant wrist, pregnancy or ≤3 mo postpartum, or any known rheumatic disorder, polyneuropathy, or uncontrolled thyroid disorder led to participant exclusion. The discovery of anatomic anomalies during data collection (i.e., bifurcated median nerve or Martin Gruber anastomosis) was a cause for exclusion after consent.
Independent Variables
A chart review provided each participant’s gender and date of birth for calculation of age (in years). Participants provided hand dominance, level of education, and occupational information on a questionnaire. Level of education was categorized as high school, college (i.e., associate’s or bachelor’s degree), or graduate education (i.e., master’s or doctoral degree). Participants indicated their level of employment (i.e., unemployed, part time, full time, retired) and provided their occupational title. Body mass index (BMI) was calculated for each participant on the basis of height (cm) and mass (kg). Researchers used an electronic caliper to measure the dominant wrist. We calculated wrist ratio as the depth (mm) divided by the width (mm) of the wrist.
We used a modified version of the Job Content Questionnaire (JCQ; Karasek et al., 1998) to obtain ratings of psychosocial strain in the workplace on the basis of decision latitude (control) and psychological demands. The JCQ has high validity (αs = .73–.74), and responses to psychological demands have a moderate correlation to job control (rs = .220–.293), making it a good tool for categorizing job strain in various occupations (Karasek et al., 1998). Job control and psychological demand scores on the modified version of the questionnaire can range from 12 to 48. Participants categorized as having active jobs had both control and demands scale scores >30 points, and those in passive occupations had scores <30 on both scales. Participants who indicated having high control and low demands were categorized as having low-strain occupations, and participants who indicated having high demands and low control were categorized as having high-strain occupations.
A Logiq i hand-carried ultrasound console with a 12-MHz linear array transducer (GE Healthcare Ultrasound, Milwaukee, WI) was used to collect images of the median nerve for every participant. Ultrasonography was completed using a previously published protocol (Roll & Evans, 2009). Locations for collection of cross-sectional images in the dominant upper extremity of each participant included (1) forearm 6 cm from the distal wrist crease, (2) middle carpal tunnel at the level of the pisiform, and (3) distal carpal tunnel at the hook of the hamate.
After collection of the three cross-sectional images, researchers blinded to participant complaints completed measurements of the median nerve images. Median nerve morphology was observed using three different measures:
  1. 1.A direct trace along the inner hypoechoic (i.e., bright) border of the median nerve provided a measurement of the cross-sectional area (CSA) of the median nerve in forearm and mid–carpal tunnel.
  2. 2.Subtracting the CSA at the pisiform from the CSA in the forearm provided a measurement of the change in CSA, an indication of median nerve swelling.
  3. 3.Measurement of the perpendicular distance from the outer edge of the flexor retinaculum to a line drawn from the insertion points of the ligament on the trapezium and hook of the hamate indicated the amount of anterior bulging of the retinaculum.
To minimize error resulting from overestimating or underestimating the measures, the researchers completed each measurement 5 times, dropped the highest and lowest measures, and averaged the remaining three measures.
Dependent Variable
Subjective report of symptoms or functional deficit resulting from median nerve pathology (e.g., numbness and pain, decreased ability to complete fine motor tasks) provided a grouping mechanism that served as the dependent measure in the regression model. Participants completed the Boston Carpal Tunnel Questionnaire (BCTQ; Levine et al., 1993) to provide a measure of subjective symptom and functional status in the dominant hand. Cronbach’s α values for the BCTQ range from .80 to .90 for the Symptom Severity scale and from .88 to .93 for the Functional Status scale, and both scales have high test–retest reliability (rs = .91 and .93, respectively; Leite, Jerosch-Herold, & Song, 2006). Respondents to this questionnaire provide a rating that indicates severity of symptoms or functional deficits resulting from median nerve pathology on a scale ranging from 1 to 5, where 1 = no symptoms or limitations and 5 = maximum symptoms or limitations. Participant responses to questions on each scale were coded, and average scores for both symptom severity and functional status were obtained. Categorization as having complaints of median nerve pathology included those participants with average symptom severity or functional status scores >1.0, and participants with average scores of 1.0 on both scales had no complaints related to median nerve pathology.
Statistical Analysis
We calculated descriptive statistics for each independent variable, and participants were categorized on the basis of BCTQ results. Occupations were categorized on the basis of JCQ results to obtain a descriptive grouping for qualitative discussion and comparison. We evaluated differences between participants with and without complaints for each independent variable, using t tests or χ2 analysis as indicated by the level of measurement. Unadjusted odds ratios were calculated for the contribution of each individual variable to the BCTQ grouping outcome. Variables with small units of measure were adjusted to provide appropriate odds ratios relative to the other variables. Multicollinearity analysis was completed to ensure that no variables were highly correlated.
An exploratory stepwise binary logistic regression analysis was completed to evaluate the relationship of the independent variables to complaints of median nerve pathology. We entered variables into the stepwise model on the basis of unadjusted odds ratios. Because of published literature relating gender, age, and wrist ratio to symptoms, these variables were included in the final stepwise regression regardless of individual significance to ensure the model controlled for the contribution of these factors to the other variables. Final odds ratios were calculated for variables that met the selection criteria (p = .10) and that remained in the model after forward and backward stepwise iterations.
Results
Ninety-five participants consented to participate in the study; anatomic anomalies led to the exclusion of 7 participants after consent. On the basis of BCTQ scores, 56 of the remaining 88 participants (63.6%) reported symptoms or functional limitations in their dominant hand. The t tests and χ2 analyses indicated no differences in age, gender, hand dominance, height, or wrist ratio between the two groups (Table 1). Participants with complaints had less education and higher BMI (p < .05). Additionally, participants with complaints of symptoms and functional deficits had larger median nerve measurements than participants without complaints.
Table 1.
Participant Demographic Characteristics, by Subjective Complaints of Symptoms or Functional Deficits (N = 88)
Participant Demographic Characteristics, by Subjective Complaints of Symptoms or Functional Deficits (N = 88)×
CharacteristicParticipants With Complaints (n = 56)Participants Without Complaints (n = 32)p
Frequencies
Gender, female:male44:1222:10.306
Hand dominance, right:left51:527:5.341
Education, high school:college:graduate27:18:115:17:10.001
Mean (Standard Deviation)
Age, yr44.4 (11.5)40.8 (12.3).163
Height, cm166.3 (8.4)169.0 (8.6).155
Mass, kg88.5 (21.6)74.2 (17.5).002
Body mass index32.1 (7.7)26.0 (6.1)<.001
Wrist ratio0.726 (0.044)0.717 (0.044).351
Cross-sectional area
 Forearm, mm26.06 (1.30)5.55 (0.94).038
 Pisiform, mm211.11 (4.01)8.32 (1.68)<.001
 Change, mm25.06 (3.82)2.77 (1.62)<.001
Retinacular bulge, mm3.26 (0.49)2.86 (0.49).001
Table 1.
Participant Demographic Characteristics, by Subjective Complaints of Symptoms or Functional Deficits (N = 88)
Participant Demographic Characteristics, by Subjective Complaints of Symptoms or Functional Deficits (N = 88)×
CharacteristicParticipants With Complaints (n = 56)Participants Without Complaints (n = 32)p
Frequencies
Gender, female:male44:1222:10.306
Hand dominance, right:left51:527:5.341
Education, high school:college:graduate27:18:115:17:10.001
Mean (Standard Deviation)
Age, yr44.4 (11.5)40.8 (12.3).163
Height, cm166.3 (8.4)169.0 (8.6).155
Mass, kg88.5 (21.6)74.2 (17.5).002
Body mass index32.1 (7.7)26.0 (6.1)<.001
Wrist ratio0.726 (0.044)0.717 (0.044).351
Cross-sectional area
 Forearm, mm26.06 (1.30)5.55 (0.94).038
 Pisiform, mm211.11 (4.01)8.32 (1.68)<.001
 Change, mm25.06 (3.82)2.77 (1.62)<.001
Retinacular bulge, mm3.26 (0.49)2.86 (0.49).001
×
Categorization of the reported occupations by JCQ scores resulted in most participants being categorized as having active (42.0%; n = 37) or low-strain jobs (36.4%; n = 32). Ten participants (11.4%) reported being unemployed and were not included in the descriptive report. Nearly all participants with high-strain or passive jobs (10.2%; n = 9) were in the complaint group. Approximately two-thirds of participants with active jobs (e.g., nurse assistant, registered nurse, attorney) fell into the complaint group, whereas only half of participants with low-strain jobs (e.g., occupational therapists, physical therapists, professor) had complaints. Table 2 provides a descriptive listing of all the occupational titles reported by participants, categorized by responses on the JCQ and BCTQ.
Table 2.
Occupations Reported by Participants With and Without Complaints of Symptoms or Functional Deficits, by Job Content Questionnaire Results
Occupations Reported by Participants With and Without Complaints of Symptoms or Functional Deficits, by Job Content Questionnaire Results×
Active (n = 37)Passive (n = 2)Low Strain (n = 32)High Strain (n = 7)
Participants With Complaints
Administrative assistant (2)Personal bankerAdministrative assistant (2)Bus driver (2)
AttorneySurgical technicianBabysitterRegistered nurse (3)
AudiologistCustomer service representativeTelemarketing representative
Cook, food service (2)Dock worker
Educator, faculty (5)Fellowship coordinator
Hospital administratorHome health aide
LifeguardHomemaker
Lift operatorInsurance broker
Medical technologistJanitor
Nurse anesthetistPhysical therapist
Nurse assistantPhysical therapist assistant
Painter, drywall (union)Respiratory therapist
ParamedicSchool librarian
PharmacistTherapy attendant
Registered nurse (2)
Scheduler
Service manager
Sprinkler fitter
Participants Without Complaints
AccountantAdministrative assistant (3)Undergraduate student
Administrative assistantElectromyography technician
Educator, faculty (3)Graduate student (5)
Finance directorManager
Medical transcriptionistOccupational or physical therapist (2)
Nurse case managerPhysical therapist assistant (2)
Registered nurseProfessor
Sonographer (2)Speech–language pathologist
Tax reporting managerSubstitute teacher, emergency medical technician
Table Footer NoteNote. N = 88; 10 participants were unemployed and not included in the analyses.
Note. N = 88; 10 participants were unemployed and not included in the analyses.×
Table 2.
Occupations Reported by Participants With and Without Complaints of Symptoms or Functional Deficits, by Job Content Questionnaire Results
Occupations Reported by Participants With and Without Complaints of Symptoms or Functional Deficits, by Job Content Questionnaire Results×
Active (n = 37)Passive (n = 2)Low Strain (n = 32)High Strain (n = 7)
Participants With Complaints
Administrative assistant (2)Personal bankerAdministrative assistant (2)Bus driver (2)
AttorneySurgical technicianBabysitterRegistered nurse (3)
AudiologistCustomer service representativeTelemarketing representative
Cook, food service (2)Dock worker
Educator, faculty (5)Fellowship coordinator
Hospital administratorHome health aide
LifeguardHomemaker
Lift operatorInsurance broker
Medical technologistJanitor
Nurse anesthetistPhysical therapist
Nurse assistantPhysical therapist assistant
Painter, drywall (union)Respiratory therapist
ParamedicSchool librarian
PharmacistTherapy attendant
Registered nurse (2)
Scheduler
Service manager
Sprinkler fitter
Participants Without Complaints
AccountantAdministrative assistant (3)Undergraduate student
Administrative assistantElectromyography technician
Educator, faculty (3)Graduate student (5)
Finance directorManager
Medical transcriptionistOccupational or physical therapist (2)
Nurse case managerPhysical therapist assistant (2)
Registered nurseProfessor
Sonographer (2)Speech–language pathologist
Tax reporting managerSubstitute teacher, emergency medical technician
Table Footer NoteNote. N = 88; 10 participants were unemployed and not included in the analyses.
Note. N = 88; 10 participants were unemployed and not included in the analyses.×
×
Of the unadjusted odds ratios, those for BMI, education, and all sonography measures were significant predictors of symptoms or functional deficits (p < .05). CSA change was highly correlated with CSA at the pisiform and CSA in the forearm, but the latter two measures were not highly correlated. Therefore, the evaluation of the final model did not include CSA change because of the assumption that this measure shared too much information with the other uncorrelated variables. Although age, gender, and wrist ratio were not individually significant, previous literature dictated consideration of these variables in the final regression model. Independent variables were entered into the iterative stepwise model on the basis of the unadjusted odds ratios (Table 3) for predicting complaints of median nerve pathology on the basis of BCTQ responses.
Table 3.
Unadjusted Odds Ratios of Predicting Symptoms and Functional Deficits on the Basis of Individual Characteristic Variables (N = 88)
Unadjusted Odds Ratios of Predicting Symptoms and Functional Deficits on the Basis of Individual Characteristic Variables (N = 88)×
VariableOdds Ratio95% Confidence Intervalp
Age1.0270.989, 1.067.163
Gender (female vs. male)1.6670.624, 4.454.308
Body mass index1.1461.057, 1.242<.001
Education
 High school vs. graduate4.9091.362, 17.692.015
 Undergraduate vs. graduate0.9630.326, 2.843.945
Wrist ratio (×100)1.0500.949, 1.163.345
CSA at pisiform1.3901.137, 1.699.001
Retinacular bulge (×10)1.1931.069, 1.331.002
CSA change forearm–pisiform1.3261.091, 1.611.005
Table Footer NoteNote. CSA = cross-sectional area.
Note. CSA = cross-sectional area.×
Table 3.
Unadjusted Odds Ratios of Predicting Symptoms and Functional Deficits on the Basis of Individual Characteristic Variables (N = 88)
Unadjusted Odds Ratios of Predicting Symptoms and Functional Deficits on the Basis of Individual Characteristic Variables (N = 88)×
VariableOdds Ratio95% Confidence Intervalp
Age1.0270.989, 1.067.163
Gender (female vs. male)1.6670.624, 4.454.308
Body mass index1.1461.057, 1.242<.001
Education
 High school vs. graduate4.9091.362, 17.692.015
 Undergraduate vs. graduate0.9630.326, 2.843.945
Wrist ratio (×100)1.0500.949, 1.163.345
CSA at pisiform1.3901.137, 1.699.001
Retinacular bulge (×10)1.1931.069, 1.331.002
CSA change forearm–pisiform1.3261.091, 1.611.005
Table Footer NoteNote. CSA = cross-sectional area.
Note. CSA = cross-sectional area.×
×
A significant stepwise binary logistic regression model (r2 = .281, p = .002) combined BMI, education, and CSA at the pisiform to predict the presence of complaints of symptoms or decreased function among the participants (Table 4). For every 1 mm2 increase in CSA at the pisiform, participants were 1.3 times more likely to complain of symptoms, and odds were 1.1 times higher for each unit increase in BMI. Although not significant, this exploratory model indicated a trend resulting from education whereby individuals with a high school education were 3.5 times more likely to complain of symptoms or functional limitations than those with graduate-level education.
Table 4.
Final Stepwise Binary Logistic Regression Odds Ratios for Factors Predictive of Symptoms and Functional Deficits (N = 88)
Final Stepwise Binary Logistic Regression Odds Ratios for Factors Predictive of Symptoms and Functional Deficits (N = 88)×
FactorOdds Ratio95% Confidence Intervalp
Body mass index1.0971.003, 1.200.043
Cross-sectional area at pisiform1.33381.071, 1.672.010
Education
 High school vs. graduate3.4890.823, 14.796.090
 Undergraduate vs. graduate0.8220.236, 2.861.758
Table Footer NoteNote. Model statistics: r2 = .281, p = .002.
Note. Model statistics: r2 = .281, p = .002.×
Table 4.
Final Stepwise Binary Logistic Regression Odds Ratios for Factors Predictive of Symptoms and Functional Deficits (N = 88)
Final Stepwise Binary Logistic Regression Odds Ratios for Factors Predictive of Symptoms and Functional Deficits (N = 88)×
FactorOdds Ratio95% Confidence Intervalp
Body mass index1.0971.003, 1.200.043
Cross-sectional area at pisiform1.33381.071, 1.672.010
Education
 High school vs. graduate3.4890.823, 14.796.090
 Undergraduate vs. graduate0.8220.236, 2.861.758
Table Footer NoteNote. Model statistics: r2 = .281, p = .002.
Note. Model statistics: r2 = .281, p = .002.×
×
Discussion
This preliminary study indicates that measures of median nerve morphology (i.e., CSA) may be more valuable for understanding symptoms of median nerve pathology than other previously studied factors. Previously, gender and wrist ratio were the primary personal factors studied for their relationship to CTS, whereas this analysis indicates that physiological measures of the median nerve using diagnostic ultrasonography have a stronger contribution to this disorder when considered with a patient’s BMI and level of education.
The outcomes of this exploratory analysis contrast with the results of previous studies exploring the predictability of sonographic measures. Kaymak et al. (2008)  indicated that CSA measurements of the median nerve in the carpal tunnel had no correlation to the BCTQ symptom severity and functional status scales (−0.04–0.18). Similarly, Mondelli et al. (2008)  found no direct correlation between sonographic measures and the BCTQ in a surgical population with median nerve pathology. However, after including additional personal and occupational factors in a regression analysis of the same data, a relationship of sonographic measures to subjective reports was found (Mondelli et al., 2008). For every reduction in 1 mm2 of CSA after surgery, the odds of subjective symptoms being normalized on the BCTQ increased by 20%–24%. Although this regression may support the success of surgical intervention rather than the relationship of physiology to symptoms, when combined with the results of our study, the data support continued investigation of the utility of sonographic measures in clinical practice.
The results in our study support previous research identifying BMI as a significant predictor of median nerve pathology. Our regression analysis indicated a slightly increased chance of symptoms with each unit increase in BMI, but the increased risk of CTS per unit increase in BMI has been noted to be as much as nearly double (Moghtaderi et al., 2005). Although the current study sample was not large enough to allow for a stratified comparison of various BMI levels, those with BMI >30 may be 4–9 times more likely to require surgical intervention for CTS than those with BMI <25 (Mattioli et al., 2009). Further evaluation is needed to better understand the relationship of BMI to tissue morphology and the presence of symptoms or functional deficits.
The significant influence of education on subjective reports was an unexpected outcome. Although we did not control for occupation, in theory more physically demanding jobs frequently require less education, whereas college and graduate education often lead to less physical occupations. Workers in blue-collar occupations may be up to 9 times more likely to have been surgically treated for CTS than workers in white-collar jobs (Mattioli et al., 2009). In a study of medical transcriptionists, those without a college education self-reported more upper-extremity symptoms than those with college education (Gelfman, Beebe, Amadio, Larson, & Basford, 2010). In our study, although the limited distribution of data from the JCQ disqualified those data from inclusion in the regression analysis, blue-collar occupations tended to be more typically associated with complaints. However, on the basis of the descriptive data set, many participants with skilled occupations also had complaints.
Although interesting, because none of these studies measured physical exposure, the relative importance of educational level and other occupational exposure data in development of pathology remains unclear. Moreover, the relative relationship of all personal, environmental, and occupational factors to tissue morphology requires further investigation. Use of sonography to measure CSA of the median nerve within the carpal tunnel appears to have value for predicting symptoms and functional deficits. Future studies using linear regression of the various independent factors on sonographic measures would provide stronger evidence and understanding of these relationships.
Limitations
A small, heterogeneous sample limits the ability to make broad generalizations on the basis of the results. Because of the disproportionate ratio of female to male participants in our sample, statistical power may not have been adequate to identify the contribution of gender. Matching participants on age and gender between clinical and nonclinical populations would provide better control of variables previously considered important. Categorization of participants relied on subjective reports, and diagnosis by electrodiagnostic studies was not considered; therefore, the study’s results are more applicable to an acute, clinical population with symptoms of median nerve pathology instead of a population with a chronic disorder. Finally, inclusion of precise psychosocial and physical exposure variables may enhance the interpretation of this study’s results.
Implications for Occupational Therapy Practice
The goal of rehabilitation research is to inform interventions that will prevent, reduce, or remediate disorders. CTS is often managed with splinting (Rempel, Dahlin, & Lundborg, 1999), but protective equipment alone will usually not completely remediate the problem. Similarly, effectiveness of workplace redesign to reduce physical loads remains inconclusive (van den Heuvel, de Looze, Hildebrandt, & Thé, 2003). A better understanding of physiology and tissue morphology may provide valuable information to improve or validate positive effects of therapeutic treatments.
The results of this cross-sectional data collection indicate that the physiological state of the median nerve is related to a person’s subjective experiences and occupational performance. Diagnostic ultrasonography has been successfully used in the workplace to quickly collect images of median nerve physiology without being obtrusive (Evans, Roll, Li, & Sammet, 2010), demonstrating significant implications for clinical practice. With the ability to visualize and appreciate swelling of the median nerve at the start of treatment, a therapist can confirm the pathophysiology that requires treatment.
The portability and advancing quality of sonographic equipment situates this technology perfectly for documentation of physiological changes within rehabilitation clinical practice (Roll & Evans, 2009). Continuous innovation in equipment designs and development of preset sonography parameters is making sonography equipment easier for nontraditional users to adopt. Sonography could be a highly useful tool for monitoring changes in the median nerve resulting from various physical exposures (Missere et al., 1998), and it follows that it could be useful in monitoring changes resulting from treatment exposure.
To summarize, the results of this study have the following implications for occupational therapy practice:
  • Clinicians providing interventions for carpal tunnel syndrome and other work-related musculoskeletal disorders should consider how to best target these interventions to the underlying physiological mechanisms, an approach that may ultimately affect symptoms and functional status.

  • Real-time visualization of pathophysiology and tissue morphology may improve the evaluation and interpretation of personal, environmental, or occupational risk factors for musculoskeletal disorders, leading to improved individualized treatment planning.

  • Sonographic imaging is highly portable and can provide real-time visualization of tissue morphology. It may be a valuable clinical and research tool to enhance decision making and monitor changes in tissue morphology subsequent to therapeutic interventions.

Conclusion
In summary, this study demonstrates that morphology of the median nerve measured with diagnostic ultrasonography has an important relationship to subjective complaints of symptoms and functional limitations resulting from median nerve pathology. Additional research with larger samples is required to understand the interrelationship of various personal, environmental, and occupational factors with physiological changes. This study provides preliminary evidence for the use of sonography as a clinical tool for evaluating and monitoring median nerve pathology and measuring intervention outcomes.
Acknowledgments
We could not have completed this research without the generous equipment support of GE Healthcare Ultrasound and statistical and ethical support through the National Institutes of Health Clinical and Translational Science Award to The Ohio State University. Shawn C. Roll presented portions of the data included in this article at the 13th Congress of the World Federation for Ultrasound in Medicine and Biology, August 2011, Vienna, Austria. Shawn C. Roll was funded by the National Institutes of Health Rehabilitation Research Career Development Program Grant K12 HD055929 at the time this manuscript was prepared. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the NIH.
References
Barr, A. E., Barbe, M. F., & Clark, B. D. (2004). Work-related musculoskeletal disorders of the hand and wrist: Epidemiology, pathophysiology, and sensorimotor changes. Journal of Orthopaedic and Sports Physical Therapy, 34, 610–627. [Article] [PubMed]
Barr, A. E., Barbe, M. F., & Clark, B. D. (2004). Work-related musculoskeletal disorders of the hand and wrist: Epidemiology, pathophysiology, and sensorimotor changes. Journal of Orthopaedic and Sports Physical Therapy, 34, 610–627. [Article] [PubMed]×
Bongers, P. M., Ijmker, S., van den Heuvel, S., & Blatter, B. M. (2006). Epidemiology of work related neck and upper limb problems: Psychosocial and personal risk factors (Part I) and effective interventions from a bio behavioural perspective (Part II). Journal of Occupational Rehabilitation, 16, 272–295. http://dx.doi.org/10.1007/s10926-006-9044-1 [Article]
Bongers, P. M., Ijmker, S., van den Heuvel, S., & Blatter, B. M. (2006). Epidemiology of work related neck and upper limb problems: Psychosocial and personal risk factors (Part I) and effective interventions from a bio behavioural perspective (Part II). Journal of Occupational Rehabilitation, 16, 272–295. http://dx.doi.org/10.1007/s10926-006-9044-1 [Article] ×
Bongers, P. M., Kremer, A. M., & ter Laak, J. (2002). Are psychosocial factors risk factors for symptoms and signs of the shoulder, elbow, or hand/wrist? A review of the epidemiological literature. American Journal of Industrial Medicine, 41, 315–342. http://dx.doi.org/10.1002/ajim.10050 [Article] [PubMed]
Bongers, P. M., Kremer, A. M., & ter Laak, J. (2002). Are psychosocial factors risk factors for symptoms and signs of the shoulder, elbow, or hand/wrist? A review of the epidemiological literature. American Journal of Industrial Medicine, 41, 315–342. http://dx.doi.org/10.1002/ajim.10050 [Article] [PubMed]×
Brisson, C., Laflamme, N., Moisan, J., Milot, A., Mâsse, B., & Vézina, M. (1999). Effect of family responsibilities and job strain on ambulatory blood pressure among white-collar women. Psychosomatic Medicine, 61, 205–213. [PubMed]
Brisson, C., Laflamme, N., Moisan, J., Milot, A., Mâsse, B., & Vézina, M. (1999). Effect of family responsibilities and job strain on ambulatory blood pressure among white-collar women. Psychosomatic Medicine, 61, 205–213. [PubMed]×
Devereux, J. J., Vlachonikolis, I. G., & Buckle, P. W. (2002). Epidemiological study to investigate potential interaction between physical and psychosocial factors at work that may increase the risk of symptoms of musculoskeletal disorder of the neck and upper limb. Occupational and Environmental Medicine, 59, 269–277. http://dx.doi.org/10.1136/oem.59.4.269 [Article] [PubMed]
Devereux, J. J., Vlachonikolis, I. G., & Buckle, P. W. (2002). Epidemiological study to investigate potential interaction between physical and psychosocial factors at work that may increase the risk of symptoms of musculoskeletal disorder of the neck and upper limb. Occupational and Environmental Medicine, 59, 269–277. http://dx.doi.org/10.1136/oem.59.4.269 [Article] [PubMed]×
Edimansyah, B. A., Rusli, B. N., Naing, L., Mohamed Rusli, B. A., & Winn, T. (2007). Relationship of psychosocial work factors and health-related quality of life in male automotive assembly workers in Malaysia. Industrial Health, 45, 437–448. http://dx.doi.org/10.2486/indhealth.45.437 [Article] [PubMed]
Edimansyah, B. A., Rusli, B. N., Naing, L., Mohamed Rusli, B. A., & Winn, T. (2007). Relationship of psychosocial work factors and health-related quality of life in male automotive assembly workers in Malaysia. Industrial Health, 45, 437–448. http://dx.doi.org/10.2486/indhealth.45.437 [Article] [PubMed]×
Evans, K. D., Roll, S. C., Li, X., & Sammet, S. (2010). A holistic evaluation of risk factors for work-related musculoskeletal distress among asymptomatic sonographers performing neurosonology: A pilot study. Journal of Diagnostic Medical Sonography, 26, 64–78. http://dx.doi.org/10.1177/8756479309352360 [Article]
Evans, K. D., Roll, S. C., Li, X., & Sammet, S. (2010). A holistic evaluation of risk factors for work-related musculoskeletal distress among asymptomatic sonographers performing neurosonology: A pilot study. Journal of Diagnostic Medical Sonography, 26, 64–78. http://dx.doi.org/10.1177/8756479309352360 [Article] ×
Farmer, J. E., & Davis, T. R. (2008). Carpal tunnel syndrome: A case-control study evaluating its relationship with body mass index and hand and wrist measurements. Journal of Hand Surgery, 33, 445–448. http://dx.doi.org/10.1177/1753193408090142 [Article] [PubMed]
Farmer, J. E., & Davis, T. R. (2008). Carpal tunnel syndrome: A case-control study evaluating its relationship with body mass index and hand and wrist measurements. Journal of Hand Surgery, 33, 445–448. http://dx.doi.org/10.1177/1753193408090142 [Article] [PubMed]×
Feuerstein, M., Shaw, W. S., Nicholas, R. A., & Huang, G. D. (2004). From confounders to suspected risk factors: Psychosocial factors and work-related upper extremity disorders. Journal of Electromyography and Kinesiology, 14, 171–178. http://dx.doi.org/10.1016/j.jelekin.2003.09.016 [Article] [PubMed]
Feuerstein, M., Shaw, W. S., Nicholas, R. A., & Huang, G. D. (2004). From confounders to suspected risk factors: Psychosocial factors and work-related upper extremity disorders. Journal of Electromyography and Kinesiology, 14, 171–178. http://dx.doi.org/10.1016/j.jelekin.2003.09.016 [Article] [PubMed]×
Gelfman, R., Beebe, T. J., Amadio, P. C., Larson, D. R., & Basford, J. R. (2010). Correlates of upper extremity disability in medical transcriptionists. Journal of Occupational Rehabilitation, 20, 340–348. http://dx.doi.org/10.1007/s10926-010-9235-7 [Article] [PubMed]
Gelfman, R., Beebe, T. J., Amadio, P. C., Larson, D. R., & Basford, J. R. (2010). Correlates of upper extremity disability in medical transcriptionists. Journal of Occupational Rehabilitation, 20, 340–348. http://dx.doi.org/10.1007/s10926-010-9235-7 [Article] [PubMed]×
Gordon, C., Johnson, E. W., Gatens, P. F., & Ashton, J. J. (1988). Wrist ratio correlation with carpal tunnel syndrome in industry. American Journal of Physical Medicine and Rehabilitation, 67, 270–272. http://dx.doi.org/10.1097/00002060-198810000-00013 [Article] [PubMed]
Gordon, C., Johnson, E. W., Gatens, P. F., & Ashton, J. J. (1988). Wrist ratio correlation with carpal tunnel syndrome in industry. American Journal of Physical Medicine and Rehabilitation, 67, 270–272. http://dx.doi.org/10.1097/00002060-198810000-00013 [Article] [PubMed]×
Hagberg, M., Vilhemsson, R., Tornqvist, E. W., & Toomingas, A. (2007). Incidence of self-reported reduced productivity owing to musculoskeletal symptoms: Association with workplace and individual factors among computer users. Ergonomics, 50, 1820–1834. http://dx.doi.org/10.1080/00140130701674539 [Article] [PubMed]
Hagberg, M., Vilhemsson, R., Tornqvist, E. W., & Toomingas, A. (2007). Incidence of self-reported reduced productivity owing to musculoskeletal symptoms: Association with workplace and individual factors among computer users. Ergonomics, 50, 1820–1834. http://dx.doi.org/10.1080/00140130701674539 [Article] [PubMed]×
Hägg, G. M., Oster, J., & Byström, S. (1997). Forearm muscular load and wrist angle among automobile assembly line workers in relation to symptoms. Applied Ergonomics, 28, 41–47. http://dx.doi.org/10.1016/S0003-6870(96)00033-6 [Article] [PubMed]
Hägg, G. M., Oster, J., & Byström, S. (1997). Forearm muscular load and wrist angle among automobile assembly line workers in relation to symptoms. Applied Ergonomics, 28, 41–47. http://dx.doi.org/10.1016/S0003-6870(96)00033-6 [Article] [PubMed]×
Huang, G. D., Feuerstein, M., & Sauter, S. L. (2002). Occupational stress and work-related upper extremity disorders: Concepts and models. American Journal of Industrial Medicine, 41, 298–314. http://dx.doi.org/10.1002/ajim.10045 [Article] [PubMed]
Huang, G. D., Feuerstein, M., & Sauter, S. L. (2002). Occupational stress and work-related upper extremity disorders: Concepts and models. American Journal of Industrial Medicine, 41, 298–314. http://dx.doi.org/10.1002/ajim.10045 [Article] [PubMed]×
Kamolz, L. P., Beck, H., Haslik, W., Högler, R., Rab, M., Schrögendorfer, K. F., & Frey, M. (2004). Carpal tunnel syndrome: A question of hand and wrist configurations. Journal of Hand Surgery, 29, 321–324. http://dx.doi.org/10.1016/j.jhsb.2003.09.010 [Article]
Kamolz, L. P., Beck, H., Haslik, W., Högler, R., Rab, M., Schrögendorfer, K. F., & Frey, M. (2004). Carpal tunnel syndrome: A question of hand and wrist configurations. Journal of Hand Surgery, 29, 321–324. http://dx.doi.org/10.1016/j.jhsb.2003.09.010 [Article] ×
Karasek, R., Brisson, C., Kawakami, N., Houtman, I., Bongers, P., & Amick, B. (1998). The Job Content Questionnaire (JCQ): An instrument for internationally comparative assessments of psychosocial job characteristics. Journal of Occupational Health Psychology, 3, 322–355. http://dx.doi.org/10.1037/1076-8998.3.4.322 [Article] [PubMed]
Karasek, R., Brisson, C., Kawakami, N., Houtman, I., Bongers, P., & Amick, B. (1998). The Job Content Questionnaire (JCQ): An instrument for internationally comparative assessments of psychosocial job characteristics. Journal of Occupational Health Psychology, 3, 322–355. http://dx.doi.org/10.1037/1076-8998.3.4.322 [Article] [PubMed]×
Kawakami, N., Kobayashi, F., Araki, S., Haratani, T., & Furui, H. (1995). Assessment of job stress dimensions based on the job demands–control model of employees of telecommunication and electric power companies in Japan: Reliability and validity of the Japanese version of the Job Content Questionnaire. International Journal of Behavioral Medicine, 2, 358–375. http://dx.doi.org/10.1207/s15327558ijbm0204_5 [Article] [PubMed]
Kawakami, N., Kobayashi, F., Araki, S., Haratani, T., & Furui, H. (1995). Assessment of job stress dimensions based on the job demands–control model of employees of telecommunication and electric power companies in Japan: Reliability and validity of the Japanese version of the Job Content Questionnaire. International Journal of Behavioral Medicine, 2, 358–375. http://dx.doi.org/10.1207/s15327558ijbm0204_5 [Article] [PubMed]×
Kaymak, B., Ozçakar, L., Cetin, A., Candan Cetin, M., Akinci, A., & Hasçelik, Z. (2008). A comparison of the benefits of sonography and electrophysiologic measurements as predictors of symptom severity and functional status in patients with carpal tunnel syndrome. Archives of Physical Medicine and Rehabilitation, 89, 743–748. http://dx.doi.org/10.1016/j.apmr.2007.09.041 [Article] [PubMed]
Kaymak, B., Ozçakar, L., Cetin, A., Candan Cetin, M., Akinci, A., & Hasçelik, Z. (2008). A comparison of the benefits of sonography and electrophysiologic measurements as predictors of symptom severity and functional status in patients with carpal tunnel syndrome. Archives of Physical Medicine and Rehabilitation, 89, 743–748. http://dx.doi.org/10.1016/j.apmr.2007.09.041 [Article] [PubMed]×
Keir, P. J. (2001). Magnetic resonance imaging as a research tool for biomechanical studies of the wrist. Seminars in Musculoskeletal Radiology, 5, 241–250. http://dx.doi.org/10.1055/s-2001-17542 [Article] [PubMed]
Keir, P. J. (2001). Magnetic resonance imaging as a research tool for biomechanical studies of the wrist. Seminars in Musculoskeletal Radiology, 5, 241–250. http://dx.doi.org/10.1055/s-2001-17542 [Article] [PubMed]×
Leite, J. C., Jerosch-Herold, C., & Song, F. (2006). A systematic review of the psychometric properties of the Boston Carpal Tunnel Questionnaire. BMC Musculoskeletal Disorders, 7, 78. http://dx.doi.org/10.1186/1471-2474-7-78 [Article] [PubMed]
Leite, J. C., Jerosch-Herold, C., & Song, F. (2006). A systematic review of the psychometric properties of the Boston Carpal Tunnel Questionnaire. BMC Musculoskeletal Disorders, 7, 78. http://dx.doi.org/10.1186/1471-2474-7-78 [Article] [PubMed]×
Levine, D. W., Simmons, B. P., Koris, M. J., Daltroy, L. H., Hohl, G. G., Fossel, A. H., & Katz, J. N. (1993). A self-administered questionnaire for the assessment of severity of symptoms and functional status in carpal tunnel syndrome. Journal of Bone and Joint Surgery, 75, 1585–1592. [PubMed]
Levine, D. W., Simmons, B. P., Koris, M. J., Daltroy, L. H., Hohl, G. G., Fossel, A. H., & Katz, J. N. (1993). A self-administered questionnaire for the assessment of severity of symptoms and functional status in carpal tunnel syndrome. Journal of Bone and Joint Surgery, 75, 1585–1592. [PubMed]×
Lim, P. G., Tan, S., & Ahmad, T. S. (2008). The role of wrist anthropometric measurement in idiopathic carpal tunnel syndrome. Journal of Hand Surgery, 33, 645–647. http://dx.doi.org/10.1177/1753193408093326 [Article] [PubMed]
Lim, P. G., Tan, S., & Ahmad, T. S. (2008). The role of wrist anthropometric measurement in idiopathic carpal tunnel syndrome. Journal of Hand Surgery, 33, 645–647. http://dx.doi.org/10.1177/1753193408093326 [Article] [PubMed]×
Lundberg, U. (2002). Psychophysiology of work: Stress, gender, endocrine response, and work-related upper extremity disorders. American Journal of Industrial Medicine, 41, 383–392. http://dx.doi.org/10.1002/ajim.10038 [Article] [PubMed]
Lundberg, U. (2002). Psychophysiology of work: Stress, gender, endocrine response, and work-related upper extremity disorders. American Journal of Industrial Medicine, 41, 383–392. http://dx.doi.org/10.1002/ajim.10038 [Article] [PubMed]×
Mattioli, S., Baldasseroni, A., Bovenzi, M., Curti, S., Cooke, R. M., Campo, G., … Violante, F. S. (2009). Risk factors for operated carpal tunnel syndrome: A multicenter population-based case-control study. BMC Public Health, 9, 343. http://dx.doi.org/10.1186/1471-2458-9-343 [Article] [PubMed]
Mattioli, S., Baldasseroni, A., Bovenzi, M., Curti, S., Cooke, R. M., Campo, G., … Violante, F. S. (2009). Risk factors for operated carpal tunnel syndrome: A multicenter population-based case-control study. BMC Public Health, 9, 343. http://dx.doi.org/10.1186/1471-2458-9-343 [Article] [PubMed]×
Missere, M., Lodi, V., Naldi, M., Caso, M. A., Prati, F., & Raffi, G. B. (1998). Use of ultrasonography in monitoring work-related carpal tunnel syndrome: A case report. American Journal of Industrial Medicine, 33, 560–564. http://dx.doi.org/10.1002/(SICI)1097-0274(199806)33:6<560::AID-AJIM6>3.0.CO;2-U [Article] [PubMed]
Missere, M., Lodi, V., Naldi, M., Caso, M. A., Prati, F., & Raffi, G. B. (1998). Use of ultrasonography in monitoring work-related carpal tunnel syndrome: A case report. American Journal of Industrial Medicine, 33, 560–564. http://dx.doi.org/10.1002/(SICI)1097-0274(199806)33:6<560::AID-AJIM6>3.0.CO;2-U [Article] [PubMed]×
Moghtaderi, A., Izadi, S., & Sharafadinzadeh, N. (2005). An evaluation of gender, body mass index, wrist circumference and wrist ratio as independent risk factors for carpal tunnel syndrome. Acta Neurologica Scandinavica, 112, 375–379. http://dx.doi.org/10.1111/j.1600-0404.2005.00528.x [Article] [PubMed]
Moghtaderi, A., Izadi, S., & Sharafadinzadeh, N. (2005). An evaluation of gender, body mass index, wrist circumference and wrist ratio as independent risk factors for carpal tunnel syndrome. Acta Neurologica Scandinavica, 112, 375–379. http://dx.doi.org/10.1111/j.1600-0404.2005.00528.x [Article] [PubMed]×
Mondelli, M., Filippou, G., Aretini, A., Frediani, B., & Reale, F. (2008). Ultrasonography before and after surgery in carpal tunnel syndrome and relationship with clinical and electrophysiological findings: A new outcome predictor. Scandinavian Journal of Rheumatology, 37, 219–224. http://dx.doi.org/10.1080/03009740801914850 [Article] [PubMed]
Mondelli, M., Filippou, G., Aretini, A., Frediani, B., & Reale, F. (2008). Ultrasonography before and after surgery in carpal tunnel syndrome and relationship with clinical and electrophysiological findings: A new outcome predictor. Scandinavian Journal of Rheumatology, 37, 219–224. http://dx.doi.org/10.1080/03009740801914850 [Article] [PubMed]×
Park, R. M., Krebs, J. M., & Mirer, F. E. (1996). Occupational disease surveillance using disability insurance at an automotive stamping and assembly complex. Journal of Occupational and Environmental Medicine, 38, 1111–1123. http://dx.doi.org/10.1097/00043764-199611000-00011 [Article] [PubMed]
Park, R. M., Krebs, J. M., & Mirer, F. E. (1996). Occupational disease surveillance using disability insurance at an automotive stamping and assembly complex. Journal of Occupational and Environmental Medicine, 38, 1111–1123. http://dx.doi.org/10.1097/00043764-199611000-00011 [Article] [PubMed]×
Radecki, P. (1994). A gender-specific wrist ratio and the likelihood of a median nerve abnormality at the carpal tunnel. American Journal of Physical Medicine and Rehabilitation, 73, 157–162. http://dx.doi.org/10.1097/00002060-199406000-00003 [Article] [PubMed]
Radecki, P. (1994). A gender-specific wrist ratio and the likelihood of a median nerve abnormality at the carpal tunnel. American Journal of Physical Medicine and Rehabilitation, 73, 157–162. http://dx.doi.org/10.1097/00002060-199406000-00003 [Article] [PubMed]×
Rempel, D., Bach, J. M., Gordon, L., & So, Y. (1998). Effects of forearm pronation/supination on carpal tunnel pressure. Journal of Hand Surgery, 23, 38–42. http://dx.doi.org/10.1016/S0363-5023(98)80086-5 [Article] [PubMed]
Rempel, D., Bach, J. M., Gordon, L., & So, Y. (1998). Effects of forearm pronation/supination on carpal tunnel pressure. Journal of Hand Surgery, 23, 38–42. http://dx.doi.org/10.1016/S0363-5023(98)80086-5 [Article] [PubMed]×
Rempel, D., Dahlin, L., & Lundborg, G. (1999). Pathophysiology of nerve compression syndromes: Response of peripheral nerves to loading. Journal of Bone and Joint Surgery, 81, 1600–1610. [PubMed]
Rempel, D., Dahlin, L., & Lundborg, G. (1999). Pathophysiology of nerve compression syndromes: Response of peripheral nerves to loading. Journal of Bone and Joint Surgery, 81, 1600–1610. [PubMed]×
Rissén, D., Melin, B., Sandsjö, L., Dohns, I., & Lundberg, U. (2000). Surface EMG and psychophysiological stress reactions in women during repetitive work. European Journal of Applied Physiology, 83, 215–222. http://dx.doi.org/10.1007/s004210000281 [Article] [PubMed]
Rissén, D., Melin, B., Sandsjö, L., Dohns, I., & Lundberg, U. (2000). Surface EMG and psychophysiological stress reactions in women during repetitive work. European Journal of Applied Physiology, 83, 215–222. http://dx.doi.org/10.1007/s004210000281 [Article] [PubMed]×
Roll, S. C., Case-Smith, J., & Evans, K. D. (2011). Diagnostic accuracy of ultrasonography vs. electromyography in carpal tunnel syndrome: A systematic review of literature. Ultrasound in Medicine and Biology, 37, 1539–1553. http://dx.doi.org/10.1016/j.ultrasmedbio.2011.06.011 [Article] [PubMed]
Roll, S. C., Case-Smith, J., & Evans, K. D. (2011). Diagnostic accuracy of ultrasonography vs. electromyography in carpal tunnel syndrome: A systematic review of literature. Ultrasound in Medicine and Biology, 37, 1539–1553. http://dx.doi.org/10.1016/j.ultrasmedbio.2011.06.011 [Article] [PubMed]×
Roll, S. C., & Evans, K. (2009). Feasibility of using a hand-carried sonographic unit for investigating median nerve pathology. Journal of Diagnostic Medical Sonography, 25, 241–249. http://dx.doi.org/10.1177/8756479309345284 [Article]
Roll, S. C., & Evans, K. (2009). Feasibility of using a hand-carried sonographic unit for investigating median nerve pathology. Journal of Diagnostic Medical Sonography, 25, 241–249. http://dx.doi.org/10.1177/8756479309345284 [Article] ×
Roll, S. C., Evans, K. D., Li, X., Freimer, M., & Sommerich, C. M. (2011). Screening for carpal tunnel syndrome using sonography. Journal of Ultrasound in Medicine, 30, 1657–1667. [PubMed]
Roll, S. C., Evans, K. D., Li, X., Freimer, M., & Sommerich, C. M. (2011). Screening for carpal tunnel syndrome using sonography. Journal of Ultrasound in Medicine, 30, 1657–1667. [PubMed]×
Sharifi-Mollayousefi, A., Yazdchi-Marandi, M., Ayramlou, H., Heidari, P., Salavati, A., Zarrintan, S., & Sharifi-Mollayousefi, A. (2008). Assessment of body mass index and hand anthropometric measurements as independent risk factors for carpal tunnel syndrome. Folia Morphologica, 67, 36–42. [PubMed]
Sharifi-Mollayousefi, A., Yazdchi-Marandi, M., Ayramlou, H., Heidari, P., Salavati, A., Zarrintan, S., & Sharifi-Mollayousefi, A. (2008). Assessment of body mass index and hand anthropometric measurements as independent risk factors for carpal tunnel syndrome. Folia Morphologica, 67, 36–42. [PubMed]×
Skie, M., Zeiss, J., Ebraheim, N. A., & Jackson, W. T. (1990). Carpal tunnel changes and median nerve compression during wrist flexion and extension seen by magnetic resonance imaging. Journal of Hand Surgery, 15, 934–939. http://dx.doi.org/10.1016/0363-5023(90)90019-N [Article] [PubMed]
Skie, M., Zeiss, J., Ebraheim, N. A., & Jackson, W. T. (1990). Carpal tunnel changes and median nerve compression during wrist flexion and extension seen by magnetic resonance imaging. Journal of Hand Surgery, 15, 934–939. http://dx.doi.org/10.1016/0363-5023(90)90019-N [Article] [PubMed]×
van den Heuvel, S. G., de Looze, M. P., Hildebrandt, V. H., & Thé, K. H. (2003). Effects of software programs stimulating regular breaks and exercises on work-related neck and upper-limb disorders. Scandinavian Journal of Work, Environment and Health, 29, 106–116. http://dx.doi.org/10.5271/sjweh.712 [Article]
van den Heuvel, S. G., de Looze, M. P., Hildebrandt, V. H., & Thé, K. H. (2003). Effects of software programs stimulating regular breaks and exercises on work-related neck and upper-limb disorders. Scandinavian Journal of Work, Environment and Health, 29, 106–116. http://dx.doi.org/10.5271/sjweh.712 [Article] ×
Viikari-Juntura, E., & Silverstein, B. (1999). Role of physical load factors in carpal tunnel syndrome. Scandinavian Journal of Work, Environment and Health, 25, 163–185. http://dx.doi.org/10.5271/sjweh.423 [Article]
Viikari-Juntura, E., & Silverstein, B. (1999). Role of physical load factors in carpal tunnel syndrome. Scandinavian Journal of Work, Environment and Health, 25, 163–185. http://dx.doi.org/10.5271/sjweh.423 [Article] ×
Table 1.
Participant Demographic Characteristics, by Subjective Complaints of Symptoms or Functional Deficits (N = 88)
Participant Demographic Characteristics, by Subjective Complaints of Symptoms or Functional Deficits (N = 88)×
CharacteristicParticipants With Complaints (n = 56)Participants Without Complaints (n = 32)p
Frequencies
Gender, female:male44:1222:10.306
Hand dominance, right:left51:527:5.341
Education, high school:college:graduate27:18:115:17:10.001
Mean (Standard Deviation)
Age, yr44.4 (11.5)40.8 (12.3).163
Height, cm166.3 (8.4)169.0 (8.6).155
Mass, kg88.5 (21.6)74.2 (17.5).002
Body mass index32.1 (7.7)26.0 (6.1)<.001
Wrist ratio0.726 (0.044)0.717 (0.044).351
Cross-sectional area
 Forearm, mm26.06 (1.30)5.55 (0.94).038
 Pisiform, mm211.11 (4.01)8.32 (1.68)<.001
 Change, mm25.06 (3.82)2.77 (1.62)<.001
Retinacular bulge, mm3.26 (0.49)2.86 (0.49).001
Table 1.
Participant Demographic Characteristics, by Subjective Complaints of Symptoms or Functional Deficits (N = 88)
Participant Demographic Characteristics, by Subjective Complaints of Symptoms or Functional Deficits (N = 88)×
CharacteristicParticipants With Complaints (n = 56)Participants Without Complaints (n = 32)p
Frequencies
Gender, female:male44:1222:10.306
Hand dominance, right:left51:527:5.341
Education, high school:college:graduate27:18:115:17:10.001
Mean (Standard Deviation)
Age, yr44.4 (11.5)40.8 (12.3).163
Height, cm166.3 (8.4)169.0 (8.6).155
Mass, kg88.5 (21.6)74.2 (17.5).002
Body mass index32.1 (7.7)26.0 (6.1)<.001
Wrist ratio0.726 (0.044)0.717 (0.044).351
Cross-sectional area
 Forearm, mm26.06 (1.30)5.55 (0.94).038
 Pisiform, mm211.11 (4.01)8.32 (1.68)<.001
 Change, mm25.06 (3.82)2.77 (1.62)<.001
Retinacular bulge, mm3.26 (0.49)2.86 (0.49).001
×
Table 2.
Occupations Reported by Participants With and Without Complaints of Symptoms or Functional Deficits, by Job Content Questionnaire Results
Occupations Reported by Participants With and Without Complaints of Symptoms or Functional Deficits, by Job Content Questionnaire Results×
Active (n = 37)Passive (n = 2)Low Strain (n = 32)High Strain (n = 7)
Participants With Complaints
Administrative assistant (2)Personal bankerAdministrative assistant (2)Bus driver (2)
AttorneySurgical technicianBabysitterRegistered nurse (3)
AudiologistCustomer service representativeTelemarketing representative
Cook, food service (2)Dock worker
Educator, faculty (5)Fellowship coordinator
Hospital administratorHome health aide
LifeguardHomemaker
Lift operatorInsurance broker
Medical technologistJanitor
Nurse anesthetistPhysical therapist
Nurse assistantPhysical therapist assistant
Painter, drywall (union)Respiratory therapist
ParamedicSchool librarian
PharmacistTherapy attendant
Registered nurse (2)
Scheduler
Service manager
Sprinkler fitter
Participants Without Complaints
AccountantAdministrative assistant (3)Undergraduate student
Administrative assistantElectromyography technician
Educator, faculty (3)Graduate student (5)
Finance directorManager
Medical transcriptionistOccupational or physical therapist (2)
Nurse case managerPhysical therapist assistant (2)
Registered nurseProfessor
Sonographer (2)Speech–language pathologist
Tax reporting managerSubstitute teacher, emergency medical technician
Table Footer NoteNote. N = 88; 10 participants were unemployed and not included in the analyses.
Note. N = 88; 10 participants were unemployed and not included in the analyses.×
Table 2.
Occupations Reported by Participants With and Without Complaints of Symptoms or Functional Deficits, by Job Content Questionnaire Results
Occupations Reported by Participants With and Without Complaints of Symptoms or Functional Deficits, by Job Content Questionnaire Results×
Active (n = 37)Passive (n = 2)Low Strain (n = 32)High Strain (n = 7)
Participants With Complaints
Administrative assistant (2)Personal bankerAdministrative assistant (2)Bus driver (2)
AttorneySurgical technicianBabysitterRegistered nurse (3)
AudiologistCustomer service representativeTelemarketing representative
Cook, food service (2)Dock worker
Educator, faculty (5)Fellowship coordinator
Hospital administratorHome health aide
LifeguardHomemaker
Lift operatorInsurance broker
Medical technologistJanitor
Nurse anesthetistPhysical therapist
Nurse assistantPhysical therapist assistant
Painter, drywall (union)Respiratory therapist
ParamedicSchool librarian
PharmacistTherapy attendant
Registered nurse (2)
Scheduler
Service manager
Sprinkler fitter
Participants Without Complaints
AccountantAdministrative assistant (3)Undergraduate student
Administrative assistantElectromyography technician
Educator, faculty (3)Graduate student (5)
Finance directorManager
Medical transcriptionistOccupational or physical therapist (2)
Nurse case managerPhysical therapist assistant (2)
Registered nurseProfessor
Sonographer (2)Speech–language pathologist
Tax reporting managerSubstitute teacher, emergency medical technician
Table Footer NoteNote. N = 88; 10 participants were unemployed and not included in the analyses.
Note. N = 88; 10 participants were unemployed and not included in the analyses.×
×
Table 3.
Unadjusted Odds Ratios of Predicting Symptoms and Functional Deficits on the Basis of Individual Characteristic Variables (N = 88)
Unadjusted Odds Ratios of Predicting Symptoms and Functional Deficits on the Basis of Individual Characteristic Variables (N = 88)×
VariableOdds Ratio95% Confidence Intervalp
Age1.0270.989, 1.067.163
Gender (female vs. male)1.6670.624, 4.454.308
Body mass index1.1461.057, 1.242<.001
Education
 High school vs. graduate4.9091.362, 17.692.015
 Undergraduate vs. graduate0.9630.326, 2.843.945
Wrist ratio (×100)1.0500.949, 1.163.345
CSA at pisiform1.3901.137, 1.699.001
Retinacular bulge (×10)1.1931.069, 1.331.002
CSA change forearm–pisiform1.3261.091, 1.611.005
Table Footer NoteNote. CSA = cross-sectional area.
Note. CSA = cross-sectional area.×
Table 3.
Unadjusted Odds Ratios of Predicting Symptoms and Functional Deficits on the Basis of Individual Characteristic Variables (N = 88)
Unadjusted Odds Ratios of Predicting Symptoms and Functional Deficits on the Basis of Individual Characteristic Variables (N = 88)×
VariableOdds Ratio95% Confidence Intervalp
Age1.0270.989, 1.067.163
Gender (female vs. male)1.6670.624, 4.454.308
Body mass index1.1461.057, 1.242<.001
Education
 High school vs. graduate4.9091.362, 17.692.015
 Undergraduate vs. graduate0.9630.326, 2.843.945
Wrist ratio (×100)1.0500.949, 1.163.345
CSA at pisiform1.3901.137, 1.699.001
Retinacular bulge (×10)1.1931.069, 1.331.002
CSA change forearm–pisiform1.3261.091, 1.611.005
Table Footer NoteNote. CSA = cross-sectional area.
Note. CSA = cross-sectional area.×
×
Table 4.
Final Stepwise Binary Logistic Regression Odds Ratios for Factors Predictive of Symptoms and Functional Deficits (N = 88)
Final Stepwise Binary Logistic Regression Odds Ratios for Factors Predictive of Symptoms and Functional Deficits (N = 88)×
FactorOdds Ratio95% Confidence Intervalp
Body mass index1.0971.003, 1.200.043
Cross-sectional area at pisiform1.33381.071, 1.672.010
Education
 High school vs. graduate3.4890.823, 14.796.090
 Undergraduate vs. graduate0.8220.236, 2.861.758
Table Footer NoteNote. Model statistics: r2 = .281, p = .002.
Note. Model statistics: r2 = .281, p = .002.×
Table 4.
Final Stepwise Binary Logistic Regression Odds Ratios for Factors Predictive of Symptoms and Functional Deficits (N = 88)
Final Stepwise Binary Logistic Regression Odds Ratios for Factors Predictive of Symptoms and Functional Deficits (N = 88)×
FactorOdds Ratio95% Confidence Intervalp
Body mass index1.0971.003, 1.200.043
Cross-sectional area at pisiform1.33381.071, 1.672.010
Education
 High school vs. graduate3.4890.823, 14.796.090
 Undergraduate vs. graduate0.8220.236, 2.861.758
Table Footer NoteNote. Model statistics: r2 = .281, p = .002.
Note. Model statistics: r2 = .281, p = .002.×
×