Carpal tunnel syndrome: role of carpal canal size

Nerve sonography in the diagnostic evaluation of primary and secondary carpal tunnel syndrome in rheumatoid arthritis

BACKGROUND AND PURPOSE

Carpal tunnel syndrome (CTS) is the most common entrapment neuropathy and extra-articular manifestation of rheumatoid arthritis (RA). However, in patients with RA, it is not always possible to clinically distinguish an actual CTS from other RA-based complaints.

METHODS

We evaluated the diagnostic role of nerve ultrasound (NUS) as supportive tool in the diagnostic process of CTS in patients with RA and tried to provide etiological clarification in cases of secondary CTS. Fifty-eight patients with RA and clinical suspicion of CTS were enrolled. All patients underwent a standardized clinical-neurological, electrophysiological (nerve conduction studies [NCS]), and NUS examination and completed the Boston CTS Questionnaire (BCTQ).

RESULTS

In 96 of 116 hands examined, a clinical suspicion of CTS was documented. In 43 of 96 (44.8%) CTS-positive hands, the diagnosis was primarily confirmed by NCS, whereas in another 16 of 96 (30.2%) hands, the diagnosis could only be verified by NUS, leading to a diagnosis of CTS in 59 of 116 (50.8%) hands. In 19 of 59 (32.3%) CTS-positive hands, tenosynovial hypertrophy was observed, and in 7 of 59 (11.8%), a cystic mass was identified as the underlying cause of secondary CTS. A good correlation between NCS and NUS findings was documented, but no significant correlation was found between NCS, NUS, and clinical findings/BCTQ.

CONCLUSIONS

In people with RA, a diagnosis of CTS purely on a clinical basis is nonspecific and should be supported by NCS and/or NUS. NUS markedly facilitates the diagnosis of CTS in these patients and enables differentiation between primary and secondary causes.

Carpal Tunnel Anthropometrics Using Acrylic Casts: A Cadaveric Study With Implications for Carpal Tunnel Release

BACKGROUND

Abundant literature exists on the morphology of the carpal tunnel. Despite this, the shape of the carpal tunnel has been reported erratically, and most studies did not attempt to correlate findings with measurements taken from cadavers. The objective of this study was to perform a morphological analysis, determine the shape and mean dimensions of the carpal tunnel, determine the level of the narrowest area of the tunnel, and establish a set of values capable of serving as a reference for carpal tunnel release.

METHODS

The carpal tunnels of 20 fresh cadaveric hands were dissected, and acrylic casts were created and measured using industrial computed tomography.

RESULTS

Of the 20 casts, 19 were shaped like elliptic cylinders, with little variation in their measurements along the length. The location of the narrowest section of the carpal tunnel is very different among casts, and the length of the roof of the carpal tunnel ranged from 21.26 to 29.86 mm.

CONCLUSIONS

The most common shape of the carpal tunnel is an elliptic cylinder. Because of the unpredictability of the location of the narrowest area of the carpal tunnel, carpal tunnel release must continue through all extension of its roof. We advise that the release should rarely be extended distally more than 30 mm from the distal palmar wrist crease, which corresponds, in most cases, to the middle of the pisiform.

Carpal tunnel mechanics and its relevance to carpal tunnel syndrome

The carpal tunnel is an elaborate biomechanical structure whose pathomechanics plays an essential role in the development of carpal tunnel syndrome. The purpose of this article is to review the movement related biomechanics of the carpal tunnel together with its anatomical and morphological features, and to describe the pathomechanics and pathophysiology associated with carpal tunnel syndrome. Topics of discussion include biomechanics of the median nerve, flexor tendons, subsynovial tissue, transverse carpal ligament, carpal tunnel pressure, and morphological properties, as well as mechanisms for biomechanical improvement and physiological restoration. It is our hope that the biomechanical knowledge of the carpal tunnel will improve the understanding and management of carpal tunnel syndrome.

Deep Learning Estimation of Median Nerve Volume Using Ultrasound Imaging in a Human Cadaver Model

Median nerve swelling is one of the features of carpal tunnel syndrome (CTS), and ultrasound measurement of maximum median nerve cross-sectional area is commonly used to diagnose CTS. We hypothesized that volume might be a more sensitive measure than cross-sectional area for CTS diagnosis. We therefore assessed the accuracy and reliability of 3-D volume measurements of the median nerve in human cadavers, comparing direct measurements with ultrasound images interpreted using deep learning algorithms. Ultrasound images of a 10-cm segment of the median nerve were used to train the U-Net model, which achieved an average volume similarity of 0.89 and area under the curve of 0.90 from the threefold cross-validation. Correlation coefficients were calculated using the areas measured by each method. The intraclass correlation coefficient was 0.86. Pearson's correlation coefficient R between the estimated volume from the manually measured cross-sectional area and the estimated volume of deep learning was 0.85. In this study using deep learning to segment the median nerve longitudinally, estimated volume had high reliability. We plan to assess its clinical usefulness in future clinical studies. The volume of the median nerve may provide useful additional information on disease severity, beyond maximum cross-sectional area.

Correlation between Electrodiagnostic Study and Imaging Features in Patients with Suspected Carpal Tunnel Syndrome

Electrodiagnostic studies (EDXs) are the confirmative diagnostic tool for carpal tunnel syndrome (CTS). Previous studies have evaluated the relationship between EDXs and ultrasonography (US) but not with X-rays. Recently, many studies on the diagnostic value of X-rays in various diseases have been reported, but data on CTS are lacking. We evaluated the relationship between electrodiagnostic parameters and roentgenographic and ultrasonographic features in CTS and investigated the usefulness of X-rays and US for CTS. This retrospective study included 97 wrists of 62 patients. All patients with suspected CTS underwent EDXs, wrist US, and wrist X-rays. The CTS patients were classified into mild, moderate, and severe groups. The roentgenographic features included the ulnar variance (UV) and the anteroposterior diameter of the wrist (APDW), and the ultrasonographic features included the flattening ratio (FR) and the thickest anteroposterior diameter of the median nerve (TAPDM). Most EDX parameters showed significant correlations with roentgenographic and US features. The electrodiagnostic severity was also correlated with all imaging features. Therefore, both wrist X-rays and wrist US can be useful for the diagnosis of CTS as supplements to EDXs.

Sonographic Diagnosis of Carpal Tunnel Syndrome

Diagnostic ultrasound in the diagnosis of carpal tunnel syndrome is firmly established. Preoperative evaluation is based on quantitative parameters such as measurement of the pathologically enlarged cross-sectional area of the nerve. The value of postoperative ultrasound lies in the visualization of the anatomy and the conclusions that can be drawn from it. It focuses on the semiquantitative sonographic parameters of nerve compression. Nerve lesions and persistent strictures can be visualized and clearly localized. In recurrent disease, the primary focus is to dynamically exclude postoperative scarring, which results in a reduction of nerve gliding.

Carpal Dimensions by Plain Wrist Radiography in Patients with Severe Carpal Tunnel Syndrome

In this study, we evaluated the diagnostic value of carpal dimensions in wrist plain radiography for the screening of carpal tunnel syndrome (CTS). This is a case-control diagnostic probe in which patients with severe CTS documented by electrodiagnostic study and healthy subjects as controls were enrolled. In the posteroanterior view of the wrist plain radiography in both groups, we defined and measured the carpal ratio, and the results were analyzed deploying statistical software. In this study, 119 participants, including 50 patients and 69 healthy subjects, were recruited. According to the ROC chart, the cutoff points, positive and negative predictive values, and the diagnostic accuracy for the cutoff points were calculated.

Study of Wrist Ratio and Wrist-to-Palm Index Radio in Individuals Suffering from Carpal Tunnel Syndrome

Background:

Carpal tunnel syndrome (CTS) is the commonest median nerve entrapment neuropathy, with preponderance in females.

Aims and Objective:

The aim of the present study was to find out wrist ratio (WR) and wrist/palm ratio (WPR) in clinically diagnosed patients of CTS.

Methodology:

One hundred individuals (fifty patients of CTS and fifty as control group) aged between 30 and 50 years were recruited for the study. Early confirmation of clinically suspected patients of CTS was done by performing electrodiagnostic tests of median and ulnar nerves. Motor and sensory conduction velocities, distal motor and sensory latencies, and F-wave latencies were performed in the recruited volunteers.

Results:

The values for mean wrist ratio in control groups were 0.694, 0.703 respectively, and in patients with carpal tunnel syndrome, it was 0.704 and 0.719 respectively in moderate and severe type. The mean wrist to palm ratio (WPR) in control group was 0.371, while in patients with CTS, it was 0.374, 0.382, 0.387, and 0.401 based on progression of severity. Both were statistically significant for the last two groups (wrist to index finger [WIF] >4.4 m/s, moderate, and WIF nonrecordable, severe). Statistically significant (P < 0.001) decrease of motor conduction velocities for median nerve was seen in the CTS group as compared to control group. Statistically significant (P < 0.001) increase in distal motor and sensory latencies was observed for both median and ulnar nerves in CTS group with more increase in distal motor latency than sensory latency. Increase in F-wave latencies of both nerves was seen in CTS group.

Conclusion:

The study results confirm selective slowing of sensory and motor conduction within wrist-to-palm segment in patients of CTS. Both WR and WPR have a progressive correlation with the severity of CTS, but statistically significant changes were seen in the groups with moderate and severe CTS. Thus, WR/WPR can act as one of the essential parameters in the diagnosis of CTS with moderate-to-severe CTS.

Importance of Recognizing Carpal Tunnel Syndrome for Neurosurgeons: A Review

Idiopathic carpal tunnel syndrome (CTS) is a common complaint, reflecting entrapment neuropathy of the upper extremity. CTS produces symptoms similar to those of other conditions, such as cervical spondylosis or ischemic or neoplastic intracranial disease. Because of these overlaps, patients with CTS are often referred to a neurosurgeon. Surgical treatment of CTS was started recently in our department. Through this experience, we realized that neurosurgeons should have an increased awareness of this condition so they can knowledgeably assess patients with a differential diagnosis that includes CTS and cervical spinal and cerebral disease. We conducted a literature review to gain the information needed to summarize current knowledge on the clinical, pathogenetic, and therapeutic aspects of CTS. Because the optimal diagnostic criteria for this disease are still undetermined, its diagnosis is based on the patient’s history and physical examination, which should be confirmed by nerve conduction studies and imaging modalities such as magnetic resonance imaging and ultrasonography. Treatment methods include observation, medication, splinting, steroid injections, and surgical intervention. Understanding the clinical features and pathogenesis of CTS, as well as the therapeutic options available to treat it, is important for neurosurgeons if they are to provide the correct management of patients with this disease.

Physiological factors influencing median nerve mobility in normal subjects

INTRODUCTION

The purpose of this study was to assess the mobility of the median nerve in the axial plane in normal healthy subjects and to evaluate physiological factors associated with lesser degrees of mobility.

METHODS

Our study included 80 healthy volunteers between 20 and 60 years of age. For all subjects, mobility of the median nerve was assessed with ultrasound at the carpal tunnel.

RESULTS

With wrist and finger flexion, the median nerve moved in all 160 wrists; in 78, the nerve dove deep to the flexor tendons (full), and in 82 it made a partial turn, but did drop below the tendons (partial). Among all demographic factors and sonographic measurements, only height was significantly related to partial mobility.

CONCLUSIONS

Full or partial mobility of the median nerve with wrist flexion is an attribute of normal subjects; partial mobility is common, particularly in taller individuals. Muscle Nerve 54: 883-886, 2016.

The Anatomical Site of Constriction of the Median Nerve in Patients with Severe Idiopathic Carpal Tunnel Syndrome

During open carpal tunnel release in patients with severe idiopathic carpal tunnel syndrome, an area of constriction in the substance of the median nerve is frequently noted. In a prospective study of 30 patients, the central point of the constricted part of the nerve was determined intraoperatively and found to be, on average, 2.5 (range 2.2–2.8) cm from the distal wrist crease. This point always corresponded to the location of the hook of the hamate bone. These intraoperative findings were compared with the “narrowest” point of the carpal canal as determined by anatomical and radiological studies in the literature.

Carpal Tunnel Syndrome: A Question of Hand and Wrist Configurations?

This study investigated whether there is an association between hand and wrist configurations and the occurrence of carpal tunnel syndrome. The external hand and wrist dimensions of 50 subjects with carpal tunnel syndrome and 50 healthy volunteers were measured and compared. In addition carpal tunnel depth and width were determined with ultrasound. Our results showed that the hand length was significantly higher in the control group (hand length, 19.0; SD, 1.0 cm: patients’ hand length, 18.2; SD, 1.1 cm) and the palm width was significantly greater in the patients’ group (palm width, 9.1; SD, 0.7 cm: controls palm width, 8.6; SD, 0.6 cm). Carpal tunnel syndrome patients had a squarer wrist (wrist ratio, 0.72; SD, 0.1) and carpal tunnel (carpal tunnel ratio, 0.48; SD, 0.1) than the controls (wrist ratio, 0.68; SD, 0.1; carpal tunnel ratio, 0.42; SD, 0.1). These findings indicate that the anatomy of the hand, wrist and carpal tunnel may predispose to carpal tunnel syndrome.

Gender differences in carpal tunnel relative cross-sectional area: a possible causative factor in idiopathic carpal tunnel syndrome

Previous research has not established a consistent difference in hand size or carpal tunnel cross-sectional area between patients with and without carpal tunnel syndrome. We tested the hypothesis that there would be no difference in relative carpal tunnel sizes between men and women. We defined relative carpal tunnel size as the cross-sectional areas at the inlet (level of the pisiform) and outlet (level of the hook of the hamate) of the carpal tunnel divided by the length of the capitate (as a measure of hand size). We made the measurements on the magnetic resonance imaging scans of 50 men and 50 women taken for symptoms unrelated to carpal tunnel syndrome. The mean relative cross-sectional area was appreciably smaller in women than men (p < 0.05). This suggests that the carpal tunnel cross-sectional area relative to the size of the hand is constitutionally smaller in women than in men. This could in theory be a significant factor in patients developing carpal tunnel syndrome.

LEVEL OF EVIDENCE

V.

An Anechoic Space at the Carpal Tunnel Inlet is a Consistent Ultrasonographic Entity which Accommodates Tendon Displacement during Finger Flexion

Background: We consistently observed the presence of anechoic spaces on standard ultrasonographic imaging of the carpal tunnel inlet in normal subjects. These spaces change in size during finger flexion and have not been characterized in a large sample of normal individuals. Ultrasonographic quantification of these spaces may indicate the available space in the region of the carpal tunnel, which allows the normal motion of tendons and the median nerve.

Methods: Transverse ultrasonographic images of the carpal tunnel inlet from 33 asymptomatic volunteers were obtained at Position A (fingers in extension) and B (fingers in flexion). Cross-sectional area (CSA), perimeter and position of anechoic space relative to median nerve were recorded.

Results: Analysis showed a 75.4% prevalence rate of a single anechoic space. Two discrete patterns were observed. 89.1% had a decrease in CSA and perimeter of anechoic space from Position A to B while 10.9% exhibited an increase. Mean position of the anechoic space is ulnar (7.49 ± 3.57 mm) and dorsal (2.18 ± 1.28 mm) to the median nerve.

Conclusions: A consistent anechoic space at the carpal tunnel inlet is seen in 75.4% of normal hands and can be quantified (cross sectional area 11.75 ± 7.36 mm2). It allows for the accommodation of flexor tendons during finger flexion.

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.

Narrowing carpal arch width to increase cross-sectional area of carpal tunnel--a cadaveric study

BACKGROUND

Carpal tunnel morphology plays an essential role in the etiology and treatment of carpal tunnel syndrome. The purpose of this study was to observe the morphological changes of the carpal tunnel as a result of carpal arch width narrowing. It was hypothesized that carpal arch width narrowing would result in increased height and area of the carpal arch.

METHODS

The carpal arch width of eight cadaveric hands was narrowed by a custom apparatus and cross-sectional ultrasound images were acquired. The carpal arch height and area were quantified as the carpal arch width was narrowed. Correlation and regression analyses were performed for the carpal arch height and area with respect to the carpal arch width.

FINDINGS

The carpal tunnel became more convex as the carpal arch width was narrowed. The initial carpal arch width, height, and area were 25.7 (SD1.9) mm, 4.1 (SD0.6) mm, and 68.5 (SD14.0) mm(2), respectively. The carpal arch height and area negatively correlated with the carpal arch width, with correlation coefficients of -0.974 (SD0.018) and -0.925 (SD0.034), respectively. Linear regression analyses showed a 1mm narrowing of the carpal arch width resulted in proportional increases of 0.40 (SD0.14) mm in the carpal arch height and 4.0 (SD2.2) mm(2) in the carpal arch area.

INTERPRETATION

This study demonstrates that carpal arch width narrowing leads to increased carpal arch height and area, a potential mechanism to reduce the mechanical insult to the median nerve and relieve symptoms associated with carpal tunnel syndrome.

Carpal Tunnel Cross-Sectional Area Affected by Soft Tissues Abutting the Carpal Bones

The carpal tunnel accommodates free movement of its contents, and the tunnel's cross-sectional area is a useful morphological parameter for the evaluation of the space available for the carpal tunnel contents and of potential nerve compression in the tunnel. The osseous boundary of the carpal bones as the dorsal border of the carpal tunnel is commonly used to determine the tunnel area, but this boundary contains soft tissues such as numerous intercarpal ligaments and the flexor carpi radialis tendon. The aims of this study were to quantify the thickness of the soft tissues abutting the carpal bones and to investigate how this soft tissue influences the calculation of the carpal tunnel area. Magnetic resonance images were analyzed for eight cadaveric specimens. A medical balloon with a physiological pressure was inserted into an evacuated tunnel to identify the carpal tunnel boundary. The balloon-based (i.e. true carpal tunnel) and osseous-based carpal tunnel boundaries were extracted and divided into regions corresponding to the hamate, capitate, trapezoid, trapezium, and transverse carpal ligament (TCL). From the two boundaries, the overall and regional soft tissue thicknesses and areas were calculated. The soft tissue thickness was significantly greater for the trapezoid (3.1±1.2mm) and trapezium (3.4±1.0mm) regions than for the hamate (0.7±0.3mm) and capitate (1.2±0.5mm) regions. The carpal tunnel area using the osseous boundary (243.0±40.4mm²) was significantly larger than the balloon-based area (183.9±29.7mm²) with a ratio of 1.32. In other words, the carpal tunnel area can be estimated as 76% (= 1/1.32) of the osseous-based area. The abundance of soft tissue in the trapezoid and trapezium regions can be attributed mainly to the capitate-trapezium ligament and the flexor carpi radialis tendon. Inclusion of such soft tissue leads to overestimations of the carpal tunnel area. Correct quantification of the carpal tunnel area aids in examining carpal tunnel stenosis as a potential risk factor for median nerve compression.

Comparison of the Diagnostic Utility of Electromyography, Ultrasonography, Computed Tomography, and Magnetic Resonance Imaging in Idiopathic Carpal Tunnel Syndrome Determined by Clinical Findings

Background:

Carpal tunnel syndrome (CTS) is the most common nerve entrapment syndrome. It is sometimes difficult to diagnose, and a late diagnosis may result in permanent nerve damage. Electromyography (EMG), ultrasonography (US), magnetic resonance imaging (MRI), and computed tomography (CT) may be performed for the diagnosis. The diagnostic accuracy of these tests is well documented, but most of these studies accept EMG as the gold standard.

Objective:

To evaluate the diagnostic accuracy of EMG, MRI, CT, and US for the diagnosis of carpal tunnel syndrome with the use of clinical findings as the gold standard.

Methods:

Patients suspected to have CTS on presentation to the outpatient clinic were evaluated. The tests were performed after a detailed physical examination. Both wrists of the 69 patients in the study were investigated.

Results:

The diagnostic accuracies of all the tests were found to be sufficient. Although EMG seemed to have the highest sensitivity and specificity, there was no statistically significant difference between the tests.

Conclusion:

EMG or US could be used as the first-step test in most cases. If they are both available, EMG should be the first choice. They may be performed together when diagnosis is challenging. CT may especially be preferred for bone-related pathological conditions, whereas MRI may be preferred for soft tissue-related pathological conditions. Even though imaging studies have been proven to be powerful diagnostic tools for CTS, no conclusive information currently exists to support replacing EMG with imaging studies.

Ultrasonographic examination of the carpal canal in dogs

The aim of this study was to determine the course of the median nerve and its adjacent structures in the carpal canals of 8 healthy dogs by using high-frequency transducers. Before performing ultrasonography, the transverse and posteroanterior diameters as well as the perimeter of the carpus were measured at just proximal to the side of the carpal pad. The anatomical structures were then determined at two levels of the carpal canal, which were named the proximal and distal levels, on the transverse sonograms. The cross-sectional areas, perimeters and the transverse and posteroanterior diameters of the median nerve were measured at these levels. Although all the measurements were larger at the proximal level, significant differences between the proximal and distal levels were determined for the cross-sectional area, the perimeter and the transverse diameter of the median nerve. On the transverse sonogram, the deep digital flexor tendon was seen in almost the center of the carpal canal like a comma shape and also it had a small concavity on the caudal side. The superficial digital flexor tendon was seen as an ovoid shape on the transverse sonograms and it was located nearly at the posterior side of the carpal canal. Both tendons were seen as intermediate-grade echogenic structures. The median artery was located inside of the concavity of the deep digital flexor tendon. Also, the median nerve was seen at the posteromedial side of the median artery. As a result of this study, the cross-sectional areas of the median nerve ranged between 1.01-2.68 mm² at the proximal level and between 0.93-1.91 mm² at the distal level.

Entrapment and compressive neuropathies

Entrapment and compressive neuropathies of the upper and lower extremities are frequently encountered disorders in the office. Certain clinical clues in the history and examination, along with electrodiagnostic testing and imaging studies, often suggest the correct diagnosis. Some of the more common neuropathies are discussed, along with suggestions regarding testing and treatment.

Wrist and carpal tunnel size and shape measurements: effects of posture

BACKGROUND

Wrist anthropometrics and posture have been implicated in the development of carpal tunnel syndrome, yet it remains unclear how external measurements relate to carpal tunnel parameters in neutral and non-neutral postures. The purposes of this study were (i) to evaluate the effect of slice orientation on several indices of carpal tunnel size and shape and (ii) to examine the relationship between carpal tunnel and external wrist dimensions.

METHODS

Three-dimensional static models were generated to measure carpal tunnel and wrist parameters for six wrists in three wrist postures (30 degrees flexion, neutral and 30 degrees extension). A simulated imaging plane enabled measurement of four carpal tunnel dimensions and two shape indices throughout the tunnel length, using "axial" and "tunnel" slice orientations (perpendicular to forearm and tunnel, respectively).

FINDINGS

Correction for tunnel orientation eliminated posture-related changes in tunnel size and shape noted at the distal end using "axial" alignment. "Tunnel" alignment reduced average carpal tunnel area and depth by nearly 15% in extension, but generally less than 5% in neutral and 2% in flexion. Subsequently, "tunnel" alignment also decreased carpal tunnel and non-circularity ratios to reveal a flatter, more elliptical shape throughout the tunnel in extension than neutral and flexion. Wrist dimensions correlated significantly with tunnel dimensions, but not tunnel shape, while wrist shape correlated significantly with tunnel shape, area and depth.

INTERPRETATIONS

Slice alignment with the carpal tunnel may improve the consistency of findings within and between patient and control populations, and enhance the diagnostic utility of imaging in clinical settings.

The role of wrist anthropometric measurement in idiopathic carpal tunnel syndrome

Anthropometric wrist measurement ratios were examined for an association with idiopathic carpal tunnel syndrome (CTS). Wrist measurements were recorded in 67 patients with CTS and in a matched control group of 67 healthy volunteers. The Wrist Ratio (WR) (wrist anterior to posterior dimension/wrist medial-lateral dimension) and the Wrist Palm Ratio (wrist anterior to posterior dimension/palm length) were calculated for each case. We found that a WR of > or =0.70 and a Wrist Palm Ratio of >0.342 were significantly associated with idiopathic CTS.

Carpal tunnel volume changes of the wrist under distraction

This study attempts to determine changes in carpal canal volume with distraction across the wrist. Uniform longitudinal distraction was maintained with two external fixators on the radial and ulnar aspects of the forearm axis of five cadaver specimens. After CT scanning, volume determinations were made at 5 mm increments beginning at the lunocapitate joint to a point 1.5 cm distal to the middle finger carpometacarpal joint. There was a statistically significant decrease of the mean total carpal canal volume from 0 to 4.54 kg of distraction, with no statistically significant decrease from 0 to 2.27 kg or 2.27 to 4.54 kg. The largest decrease occurred at 15 and 20 mm distal to the proximal edge of the transverse carpal ligament corresponding to the level of the hamate hook. Reduction in mean carpal canal volume was 10.2% and 7.5% at these distances, respectively, from 0 to 4.54 kg of distraction. Progressive distraction across the wrist causes a decrease in total carpal canal volume.

Disparity between popular (Internet) and scientific illness concepts of carpal tunnel syndrome causation

PURPOSE

To determine whether there are notable disparities between popular (Internet) and scientific (Index Medicus) theories of carpal tunnel syndrome (CTS) causation.

METHODS

Reports from 3 sources were evaluated with regard to support for etiological theories of CTS: 1) patient-oriented information on CTS from the Internet, 2) recent physician-oriented information on CTS from medical journals indexed on Index Medicus, and 3) articles addressing the etiology of CTS from the 1997 National Institute for Occupational Safety and Health report. Multiple logistic regression analyses evaluated differences in etiological theories from the 3 sources.

RESULTS

Internet sites implicated vitamin B(6) deficiency, tenosynovitis, and typing or computer use as causes for idiopathic CTS considerably more often and genetic predisposition considerably less often than recent Index Medicus scientific reports and reports reviewed by the National Institute for Occupational Safety and Health.

CONCLUSIONS

There are notable disparities between popular (Internet) and scientific (Index Medicus) theories of CTS causation.

The quality and strength of evidence for etiology: example of carpal tunnel syndrome

PURPOSE

The purpose of this investigation was to evaluate the quality and strength of scientific evidence supporting an etiologic relationship between a disease and a proposed risk factor using a scoring system based on the Bradford Hill criteria for causal association.

METHODS

A quantitative score based on the Bradford Hill criteria (qBHs) was used to evaluate 117 articles presenting original data regarding the etiology of carpal tunnel syndrome: 33 (28%) that evaluated biological (structural or genetic) risk factors, 51 (44%) that evaluated occupational (environment or activity-related) risk factors, and 33 (28%) that evaluated both types of risk factors.

RESULTS

The quantitative Bradford Hill scores of 2 independent observers showed very good agreement, supporting the reliability of the instrument. The average qBHs was 12.2 points (moderate association) among biological risk factors compared with 5.2 points (poor association) for occupational risk factors. The highest average qBHs was observed for genetic factors (14.2), race (11.7), and anthropometric measures of the wrist (11.3 points) with all studies finding a moderate causal association. The highest average qBHs among occupational risk factors was observed for activities requiring repetitive hand use (6.5 points among the 30 of 45 articles that reported a causal association), substantial exposure to vibration (6.3 points; 14 of 20 articles), and type of occupation (5.6 points; 38 of 53 articles), with the findings being much less consistent.

CONCLUSIONS

According to a quantitative analysis of published scientific evidence, the etiology of carpal tunnel syndrome is largely structural, genetic, and biological, with environmental and occupational factors such as repetitive hand use playing a minor and more debatable role. Speculative causal theories should be analyzed through a rigorous approach prior to wide adoption.

Magnetic resonance imaging of idiopathic carpal tunnel syndrome: correlation with clinical findings and electrophysiological investigation

OBJECTIVE

To compare clinical evaluation, electrophysiological investigation and magnetic resonance findings in assessing the severity of idiopathic carpal tunnel syndrome.

PATIENTS AND METHODS

Seventy-four patients with idiopathic carpal tunnel syndrome were prospectively recruited. Clinical evaluation included symptoms severity score and two-point discrimination, sensory and motor nerve conduction velocities were determined by electroneuromyography and imaging parameters were obtained after wrist magnetic resonance. The Wilcoxon test was used to define the differences between measurements of median nerve area. The Pearson and Spearman correlation tests were used to determine the relationships between all the measured parameters.

RESULTS

Cross-sectional area of median nerve was smaller at hamate level than at radio-ulnar joint and pisiform levels (p<0.001). With exception of median nerve area at hamate level, there was a lower degree of correlation between MRI parameters and findings obtained by clinical assessments and electrophysiological measurements. The median nerve area at hamate level correlated negatively with duration of symptoms, two-point discrimination, symptoms severity score and positively with sensory nerve conduction velocity (p<0.01).

CONCLUSION

In patients with idiopathic carpal tunnel syndrome, median nerve area measured by wrist magnetic resonance at hamate level may be considered as a valuable indicator to grading the severity of disease.

Ultrasonographic measurements in cubital tunnel syndrome

The cubital tunnel is the most common site of ulnar nerve entrapment. Previous ultrasound studies have demonstrated enlargement of the ulnar nerve in cubital tunnel syndrome but did not report on the cubital tunnel itself. Twenty-two individuals with cubital tunnel syndrome were evaluated with nerve conduction studies and ultrasound. The ultrasound measurement that most strongly correlated with conduction velocity was the ratio of ulnar nerve to cubital tunnel cross-sectional area with the elbow flexed. Measurement of this ratio may improve the diagnostic accuracy of ultrasound in cubital tunnel syndrome, although further investigation is needed.

Frequency and severity of carpal tunnel syndrome according to level of cervical radiculopathy: Double crush syndrome?

OBJECTIVE

The double crush hypothesis (DC) proposes that a proximal lesion along an axon predisposes it to injury at a more distal site along its course through impaired axoplasmic flow. The frequency and severity of carpal tunnel syndrome (CTS) according to the level of cervical radiculopathy were investigated to evaluate the hypothesis of DC.

METHODS

The frequency of CTS was investigated in 277 patients with C6, C7 or C8 radiculopathies and correlation between CTS and radiculopathy level was determined. We also investigated whether the degrees of abnormal sensory responses were more severe in C6, C7 radiculopathies and whether motor responses were more severe in C8 radiculopathy.

RESULTS

Thirty-nine patients were diagnosed with CTS and concomitant cervical radiculopathy at the C6, 7, or C8 root levels. The frequency of coexisting CTS was not statistically different according to the level of radiculopathy. The electrophysiologic results revealed no significant correlation between median sensory parameters and C6, C7 cases, and no relationship was observed between median motor responses and C8 radiculopathy.

CONCLUSIONS

The frequency and electrophysiologic data of CTS analyzed according to cervical radiculopathy level do not support a neurophysiological explanation.

SIGNIFICANCE

Based on this study, the DC hypothesis could not be supported.

Evaluation of work-related carpal tunnel syndrome

OBJECTIVES

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

METHODS

A comprehensive literature review.

RESULTS

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

CONCLUSIONS

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

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

OBJECTIVES

The aim of this study was to evaluate the role of gender, body mass index (BMI), wrist ratio (WR) and wrist circumference as independent risk factors for carpal tunnel syndrome (CTS) and to analyze the strength of association of these factors.

METHODS

We have undertaken a case-control study in 128 CTS patients and 109 controls. Based on clinical and electrophysiologic criteria, 109 female and 19 male CTS patients as well as 62 female and 47 male control subjects were selected from patients and their relatives referred to our hospital. In total, 179 hands with CTS in three groups of severity (mild, moderate and severe) were examined. Height, weight, BMI, wrist width, depth, circumference and ratio were measured in all patients and control group. Mean values of different risk factors for CTS group and controls were measured. A logistic regression analysis was conducted to evaluate odds ratio of different risk factors.

RESULTS

The mean values for BMI and WR were greater in CTS patients than in the subject group. Thirty-four, 89 and 57 patients had mild, moderate and severe CTS, respectively. Mean age, BMI, wrist circumference and ratio were not statistically significant in the three groups. Female gender, increased BMI and increased WR had odds ratio of 9.95, 1.75 and 1.12, respectively.

CONCLUSION

Our study confirms that female gender, obesity and square wrists are independent risk factors for CTS.

Pathomechanics of peripheral nerve loading. Evidence in carpal tunnel syndrome

Peripheral nerve injury is a common occurrence, with carpal tunnel syndrome (CTS) receiving the most attention. Nerve dysfunction associated with compression syndromes results from an interruption or localized interference of microvascular function due to structural changes in the nerves or surrounding tissues. This article reviews the physiologic, pathophysiologic, and histologic effects of compressing peripheral nerves in animal models, and then examines the evidence for similar processes in humans using CTS as a model.

Quantitative MRI of the wrist and nerve conduction studies in patients with idiopathic carpal tunnel syndrome

OBJECTIVE

To correlate morphological findings of idiopathic carpal tunnel syndrome (CTS) with the function of the median nerve.

METHODS

In this study, 105 wrists of 105 women patients with idiopathic CTS, and 36 wrists of 36 female volunteers were subjected to nerve conduction studies and MRI. Cross sectional area, signal intensity ratio, and the flattening ratio of the median nerve, carpal tunnel area, flexor tendon area, synovial area, and intersynovial space, and the palmar bowing of the transverse carpal ligament (TCL) were quantified by MRI and correlated with the severity of the disease determined by nerve conduction studies.

RESULTS

Cross sectional areas of the median nerve, flexor tendons, and carpal tunnel, and the palmar bowing of the TCL of the CTS groups were greater than in the control group, but differences were not detected among the CTS groups for the area of the flexor tendons and the carpal tunnel. Enlargement, flattening, and high signal intensity of the median nerve at the distal radioulnar joint level were more significant in the advanced than in the earlier stages of the disease. Increase in palmar bowing of the TCL was less prominent in the most advanced group. Linear correlation between the area of the carpal tunnel and palmar bowing of the TCL was noted.

CONCLUSION

Severity of the disease could be judged by evaluating not only longitudinal changes of signal intensity and configuration of the median nerve, but also palmar bowing of the TCL. Increased palmar bowing of the TCL was found to be associated with an increase in the area of the carpal tunnel.

Diagnostic Precision of Ultrasonography in Patients with Carpal Tunnel Syndrome

OBJECTIVE

To evaluate the diagnostic value of ultrasonography in patients with electrophysiologically confirmed carpal tunnel syndrome.

DESIGN

A prospective ultrasonographic study of 35 wrists with electrophysiologically confirmed carpal tunnel syndrome and of 40 normal wrists. Receiver-operating-characteristics curves for the ultrasonographic measurements of median nerve were plotted to identify the most optimal cutoff values.

RESULTS

The ultrasonographic measurements of median nerves were found to be increased significantly in patients with carpal tunnel syndrome when compared with controls, particularly in terms of cross-sectional area (P<0.001) and the bowing of the flexor retinaculum (P<0.01) but not in the flattening ratio (P>0.05). According to receiver-operating-characteristics curve results, the most optimal cutoff value for the cross-sectional area of the median nerve was obtained at the level of middle carpal tunnel, which was 9.3 mm, with a sensitivity of 80% and specificity of 77.5%. The optimal cutoff value for the bowing of the flexor retinaculum was 3.7 mm, with a sensitivity of 71.4% and specificity of 55%. No optimum cutoff value could be identified from the receiver-operating-characteristics curves for the flattening ratio of median nerve.

CONCLUSION

Ultrasonographic examination of the median nerve seems to be a promising method in the diagnosis of carpal tunnel syndrome, evaluating the morphologic changes of the median nerve in patients with clinical signs and symptoms. Further studies with wider series are needed to confirm our preliminary results.

Ultrasonographic evaluation of age-related changes in bowing of the flexor retinaculum

The effects of age, gender, and hand dominance on bowing of the flexor retinaculum, used in diagnosing carpal tunnel syndrome, were analyzed. Forty men aged 23-58 years old (39.7 +/- 11.2) and 40 women aged 20-57 years old (39.6 +/- 11.3) were the normal subjects. A total of 160 wrists was examined with a linear array transducer. Bowing of the flexor retinaculum was measured as the distance from a line drawn between the trapezium and the hamate to the palmar apex of the outer surface of the flexor retinaculum. It was 0.5-3.7 mm (2.00 +/- 0.64) for all hands, 0.6-3.7 mm (2.06 +/- 0.62) for men, 0.5-3.4 mm (1.96 +/- 0.67) for women, 0.5-3.4 mm (1.00 +/- 0.64) for dominant, and 0.6-3.7 mm (2.03 +/- 0.65) for nondominant hands. There was no difference between genders or dominant vs non-dominant hands regarding this parameter. However, it was highly correlated with age (r=0.59, p<0.0001). In conclusion, bowing of the flexor retinaculum measurements should be carefully compared with the standardized values when diagnosing carpal tunnel syndrome.

Postoperative Morphologic Analysis of Carpal Tunnel Syndrome Using High-Resolution Ultrasonography

The authors evaluated the morphologic changes that follow division of the transverse carpal ligament in patients with carpal tunnel syndrome (CTS) using high-resolution ultrasonography. Ten patients, for a total of 20 hands, underwent high-resolution ultrasonographic studies before the operation and 8 months after the operation. They were all diagnosed with bilateral idiopathic CTS. The authors evaluated the configuration of the median nerve and carpal tunnel at 3 different levels of the wrist: the distal radiocarpal joint level, the pisiform level, and the hook of hamate level. The median nerve gained in thickness to a remarkable extent at 2 distal levels after the operation. The change in morphology of the carpal tunnel at these 2 distal levels was obvious, but the cross-sectional area of the carpal tunnel was increased significantly only at the hook of hamate level. The transverse diameters of the carpal tunnel were not significantly changed. As mentioned, the authors found that the median nerve gained significantly in volume at the distal part of the carpal tunnel postoperatively, and the volumetric increase in the carpal tunnel appears to have resulted from an anterior displacement of newly formed transverse carpal ligament, rather than from a widening of the bony carpal arch.

Correlation of High-Resolution Ultrasonographic Findings With the Clinical Symptoms and Electrodiagnostic Data in Carpal Tunnel Syndrome

There are several different imaging methods that are helpful in the diagnosis of carpal tunnel syndrome, including traditional radiography, computed tomography (CT), and magnetic resonance imaging (MRI). CT and MRI offer the advantage of providing direct visualization of the structural abnormality of the carpal tunnel and median nerve, but both of these modalities are expensive and time-consuming. Recently, high-resolution ultrasonography has been reported to be effective in the study of the musculoskeletal system. The authors designed a case-control study to assess the diagnostic value of high-resolution ultrasonography. Forty-eight patients, for a total of 96 hands, whose diagnosis was confirmed by self-administered questionnaire and electrodiagnostic tests, underwent high-resolution ultrasonographic studies. The authors compared the sonographic findings with the electromyographic data and the patients' severity scores on the self-questionnaires. Proximal swelling of the median nerve at the entrance to the carpal tunnel was found to correlate with the nerve conduction data. Also, compression of the median nerve under the transverse carpal ligament was found to correlate with the subjective symptoms. Although ultrasonography is not an ideal method of diagnosis for carpal tunnel syndrome, it may be helpful for estimating the symptom severity and nerve conduction deficit.

Entrapment and compressive neuropathies

Entrapment and compressive neuropathies of the upper and lower extremities are frequently encountered disorders in the office. Certain clinical clues in the history and examination, along with electrodiagnostic testing and imaging studies, often suggest the correct diagnosis. Some of the more common neuropathies are discussed, along with suggestions regarding testing and treatment.

Computed tomography and morphometry of the carpal canal in the dog

This study has been carried out to determine the normal size and shape of the carpal canal in the dog and to describe the salient anatomic structures with the aid of computed tomography. Computed tomographic examination of the carpal region was performed in the left and right forelimbs of 5 male and 5 female healthy German shepherd dogs, respectively. Areas, depths and widths of the carpal canal and identification of the anatomical structures were determined at two levels of the carpal region. The frozen forelimbs of two cadavers were sectioned with a saw to correlate the CT images with these sections. All scans were studied using both bony and soft tissue windows. The measurements of the right and left carpal canals did not differ significantly in male or female dogs, respectively although they were larger in the male than female dogs. In addition to this, the measurements of the carpal canal were larger in the distal than the proximal slice. The lateral tip of the deep digital flexor tendon was located more cranially in the distal part than in the proximal part of the carpal canal. Thus, the distance between the bones and the deep digital flexor tendon decreased and the distance between the deep and superficial digital flexor tendons increased. This localization is important in regard to neuropathy because the median nerve was located between the deep and superficial flexor tendons and this region was wider at the distal than the proximal part of the carpal canal. As a result of this study, it was found that the carpal canal of the dog much resembled that of humans and this similarity can easily generate a predisposition to focal neuropathy namely, carpal tunnel syndrome in dogs.

Does carpal canal stenosis predict outcome in women with carpal tunnel syndrome?

OBJECTIVE

We investigated the role of carpal canal stenosis as a predictor of outcome in patients who underwent surgical treatment for carpal tunnel syndrome (CTS).

METHODS

We performed magnetic resonance imaging (MRI) of the wrist in 31 female patients with clinically and neurophysiologically confirmed CTS. With a computerized analyser we quantitatively calculated the focal narrowest point of the tunnel. Patient's assessment of CTS-related symptoms were obtained by using a visual analogue scale before, and 6 months after treatment.

RESULTS

Seventeen (56%) patients improved in all symptoms after treatment. The focal narrowest point of the tunnel was identified at its distal third in all patients, at 8 mm from the outlet. The median area of the narrowest point in those who improved clinically (n=17) was 238.9 mm2 compared with 269.8 mm2 in others (n=14), P=0.046.

CONCLUSION

Identification of carpal canal stenosis may be important in selecting candidates for treatment in symptomatic CTS.

The relationship between basal joint arthritis and carpal tunnel syndrome: an MRI pilot study

PURPOSE

This investigation explored 2 questions. First, does basal joint arthritis lead to morphologic alterations that significantly narrow the carpal tunnel? Second, does trapezial excision alter the morphology of the carpal tunnel and decompress the median nerve?

METHOD

Four patients with basal joint arthritis alone were treated with ligament reconstruction and tendon interposition (LRTI) arthroplasty. Three patients with basal joint arthritis and carpal tunnel syndrome were treated with LRTI and carpal tunnel release. Preoperative and postoperative magnetic resonance imaging (MRI) scans were obtained to assess differences in carpal tunnel volume and morphology between the groups before and after surgery.

RESULTS

The difference in preoperative carpal tunnel volume between groups was not significantly different. Carpal tunnel volume increased by 7% with LRTI and by 24% after LRTI and carpal tunnel release. The anteroposterior diameter of the carpal canal increased in both groups to allow a volar migration of the median nerve.

CONCLUSION

LRTI increases the anteroposterior diameter and volume of the carpal tunnel. A larger comparative study would be necessary to determine whether LRTI is sufficient to decompress the carpal tunnel.

Medical history of carpal tunnel syndrome

The anatomical configuration of the carpal tunnel is that of an inelastic channel. Consequently, any increase in its volume or alteration in shape will usually result in a significant increase in interstitial pressure. At a pressure threshold of 20 mm Hg to 30 mm Hg, epineurial blood flow is compromised. When that pressure is sustained, the symptoms and physical findings associated with CTS appear. Typically, patients present with intermittent pain and paresthesias in all or part of the median nerve distribution of their hand(s). As weeks and months pass, symptoms progressively increase in frequency and severity. Eventually, thenar muscle weakness develops that initially manifests itself as "fatigue," or "tiredness." The progressive increase in symptoms and physical findings, usually accompanied by a progressive deterioration in electrodiagnostic studies, facilitates the classification of the condition into early, intermediate, and advanced stages. The increase in interstitial pressure in the carpal tunnel is in the vast majority of cases idiopathic (spontaneous). It can also be caused by a myriad of other conditions that can be classified into three other categories: intrinsic factors that increase the volume of the tunnel (outside and inside the nerve), extrinsic factors that alter the contour of the tunnel, and repetitive/overuse conditions. In addition, there is another category of neuropathic factors that affect the nerve without increasing interstitial pressure. In rare situations CTS can present as an acute problem. Far less common than the chronic form of the condition, it can follow acute wrist trauma, rheumatologic disorders, hemorrhagic problems, vascular disorders affecting a patent median artery, and high pressure injection injuries. Prompt recognition is important, followed in most cases by urgent surgical decompression of the median nerve.

Carpal tunnel syndrome in radial dysplasia

We treated three patients for carpal tunnel syndrome which developed more than 10 years after reconstructive surgery for radial dysplasia. All responded to decompressive surgery. The radial carpal bones were hypoplastic in all cases, and in two we measured the carpal tunnel with computed tomography (CT). This showed that the anteroposterior diameter and cross-sectional area of the carpal tunnel were small because of the hypoplasia of the carpal bones. We believe carpal tunnel syndrome occurs with radial dysplasia because of the narrow anteroposterior diameter and small cross-sectional area of the carpal tunnel.

Carpal tunnel syndrome and hand configuration

The likelihood that hand configuration is related to the development of carpal tunnel syndrome (CTS) was examined in this study. Based on neurophysiological criteria, 50 female subjects with CTS and 50 healthy female controls were selected and their external hand dimensions were measured. Our results showed that the palm length and third digit length were significantly shorter and the palm width larger in the subjects with CTS compared with controls. Regression analysis demonstrated that the hand ratio [(palm + third digit length)/palm width] was significantly correlated with median nerve conduction measurements. The hand ratio may be a simple and useful predictive measurement in determining the tendency for CTS.

Increased risk of median nerve dysfunction in floor cleaners: a controlled clinical and neurophysiological study

We studied median nerve involvement in a group of asymptomatic handworkers at risk for carpal tunnel syndrome, and we evaluated damage to thin and thick nerve fibres in the distribution area of the median nerve. Considering floor cleaners as workers at high risk of developing cumulative traumatic disorders in the wrist, we included 42 cleaners and 41 controls. We assessed nerve conduction studies, vibration threshold, and temperature and pain thresholds of the median nerve. The cleaners had significantly impaired motor nerve conduction velocity (p = 0.006), longer sensory distal latency (p = 0.01), lower sensory amplitude (p = 0.0005), and increased difference in heat and cold threshold of the median nerve (p = 0.0002). Increased temperature threshold was associated with prolonged sensory distal latency of the median nerve in the cleaners. In conclusion, impaired neurophysiological variables in the median nerve in floor cleaners compared with controls confirm the hypothesis that those workers are at risk of developing median nerve dysfunction. Sensory nerves seem to be more susceptible to injury than motor branches.