Shear wave elastography of transverse carpal ligament increased with simulated carpal tunnel pressure.

BACKGROUND: Elevation of carpal tunnel pressure is known to be associated with carpal tunnel syndrome. This study aimed to correlate the shear wave elastography in the transverse carpal ligament (TCL) with carpal tunnel pressures using a cadaveric model. METHODS: Eight human cadaveric hands were dissected to evacuate the tunnels. A medical balloon was inserted into each tunnel and connected to a pressure regulator to simulate tunnel pressure in the range of 0-210 mmHg with an increment of 30 mmHg. Shear wave velocity and modulus was measure in the middle of TCL. RESULTS: SWV and SWE were significantly dependent on the pressure levels (p < 0.001), and positively correlated to the tunnel pressure (SWV: R = 0.997, p < 0.001; SWE: R = 0.996, p < 0.001). Regression analyses showed linear relationship SWV and pressure (SWV = 4.359 + 0.0263 * Pressure, R2 = 0.994) and between SWE and pressure (SWE = 48.927 + 1.248 * Pressure, R2 = 0.996). CONCLUSION: The study indicated that SWV and SWE in the TCL increased linearly as the tunnel pressure increased within the current pressure range. The findings suggested that SWV/SWE in the TCL has the potential for prediction of tunnel pressure and diagnosis of carpal tunnel syndrome.

Exploring pathogenic pathways in carpal tunnel syndrome: sterile inflammation and oxidative stress.

OBJECTIVES: The main objective of the current study was to find the association between oxidative stress, inflammatory markers, and electrophysiological profile with symptom severity in patients of carpal tunnel syndrome (CTS). METHODS: Thirty-two carpal tunnel syndrome patients and 32 controls were included in the study. Boston CTS questionnaire along with plasma oxidative stress markers including superoxide dismutase, malondialdehyde, and nitric oxide and inflammatory markers including IL-6 and TNF-α were compared with the electrophysiological parameters derived from nerve conduction studies. Statistical significance of the levels between groups was calculated using unpaired-t test after checking for normality with D'Agostino & Pearson omnibus normality test. RESULTS: We found that the median nerve conduction velocity was prolonged, amplitude was decreased, while the levels of oxidative stress markers like malondialdehyde (MDA), superoxidase dismutase (SOD), and nitric oxide (NO) were increased in CTS patients compared to controls. Inflammatory markers like interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) were also increased in CTS patients. We found that plasma SOD and TNF-α correlated well with the median motor amplitude. There was no other significant correlation between oxidative stress markers and inflammatory markers with nerve conduction studies or disease severity. Patients with mild disease also showed lesser levels of SOD, NO, IL-6, and TNF-α markers than patients with severe disease. CONCLUSIONS: CTS is probably a disease of sterile inflammation and disbalance of oxidative stress, with higher inflammatory and oxidative stress markers pointing to a more severe disease.

Carpal tunnel syndrome.

Carpal tunnel syndrome (CTS) is the most common nerve entrapment disorder worldwide. The epidemiology and risk factors, including family burden, for developing CTS are multi-factorial. Despite much research, its intricate pathophysiological mechanism(s) are not fully understood. An underlying subclinical neuropathy may indicate an increased susceptibility to developing CTS. Although surgery is often performed for CTS, clear international guidelines to indicate when to perform non-surgical or surgical treatment, based on stage and severity of CTS, remain to be elucidated. Neurophysiological examination, using electrophysiology or ultrasonography, performed in certain circumstances, should correlate with the history and findings in clinical examination of the person with CTS. History and clinical examination are particularly relevant globally owing to lack of other equipment. Various instruments are used to assess CTS and treatment outcomes as well as the effect of the disorder on quality of life. The surgical treatment options of CTS - open or endoscopic - offer an effective solution to mitigate functional impairments and pain. However, there are risks of post-operative persistent or recurrent symptoms, requiring meticulous diagnostic re-evaluation before any additional surgery. Health-care professionals should have increased awareness about CTS and all its implications. Future considerations of CTS include use of linked national registries to understand risk factors, explore possible screening methods, and evaluate diagnosis and treatment with a broader perspective beyond surgery, including psychological well-being.

Relationships between the global symptom score and electrophysiological findings after surgical release for carpal tunnel syndrome: Indications and outcomes.

PURPOSE: Regarding surgical indications for carpal tunnel syndrome (CTS), the hypothesis that the recovery processes of subjective symptoms differ among pain, sensory, and motor symptoms and correlate with recovery in objective nerve conduction studies was examined in the present study. METHODS: The global symptom score (GSS) is a method used to assess clinical outcomes and covers subjective symptoms, including pain (pain and nocturnal awakening), sensory (numbness and paresthesia), and motor (weakness/clumsiness) symptoms. The relationships between long-term changes in GSS and recovery in nerve conduction studies were investigated. RESULTS: Forty patients (40 hands) were included (mean age 65 years; 80% female; 68% with moderate CTS: sensory nerve conduction velocity < 45 m/s and motor nerve distal latency > 4.5 ms). Pain and nocturnal awakening rapidly subsided within 1 month after surgery and did not recur in the long term (median 5.6 years). Paresthesia significantly decreased 3 months after surgery and in the long term thereafter. Weakness/clumsiness significantly decreased at 1 year. Sensory nerve distal latency, conduction velocity, and amplitude significantly improved 3 months and 1 year after surgery, and correlated with nocturnal awakening in the short term (3 months) in moderate CTS cases. The patient satisfaction rate was 91%. CONCLUSION: Rapid recovery was observed in pain and nocturnal awakening, of which nocturnal awakening correlated with the recovery of sensory nerve conduction velocity. Patients with pain symptoms due to moderate CTS may benefit from surgical release.

Applications of ultrasound elastography to hand and upper limb disorders.

Ultrasound elastography is a recently developed method for accurate measurement of soft tissue stiffness in addition to the clinician's subjective evaluation. The present review briefly describes the ultrasound elastography techniques and outlines clinical applications for tendon, muscle, nerve, skin and other soft tissues of the hand and upper limb. Strain elastography provides a qualitative evaluation of the stiffness, and shear-wave elastography generates quantitative elastograms superimposed on a B-mode image. The stiffness in degenerative tendinopathy and/or tendon injury was significantly lower than in a normal tendon in several studies. Elastography is also a reliable method to evaluate functional muscle activity, compared to conventional surface electromyography. The median nerve is consistently stiffer in patients with carpal tunnel syndrome than in healthy subjects, on whatever ultrasound elastography technique. Elastography distinguishes normal skin from scars and can be used to evaluate scar severity and treatment. Elastography has huge clinical applications in musculoskeletal tissues. Continued development of systems and increased training of clinicians will expand our knowledge of elastography and its clinical applications in the future.

Expert consensus on the combined investigation of carpal tunnel syndrome with electrodiagnostic tests and neuromuscular ultrasound.

Expert consensus was sought to guide clinicians on the use of electrodiagnostic tests (EDX) and neuromuscular ultrasound (NMUS) in the investigation of suspected carpal tunnel syndrome (CTS). Consensus was achieved using the Delphi method via three consecutive anonymised surveys of 15 experts and was defined as rating agreement ≥ 80%. The panel agreed that combining EDX and NMUS is more informative than using each modality alone. NMUS adds value in patients with clinically suspected CTS with non-localizing or normal EDX, atypical EDX, failed CTS surgery, polyneuropathy, and CTS suspected to be secondary to structural pathology. The median nerve cross-sectional area should be measured at the site of maximal nerve enlargement, and the nerve should be scanned from mid-forearm to the palm. The group also identified those situations where the wrist-to-forearm area ratio and longitudinal scans of the median nerve should also be obtained. EDX should always be performed to quantify CTS severity and in individuals over age 70. This document is an initial step to guide clinicians on the combined investigation of CTS using EDX and NMUS, to be updated regularly with the emergence of new research.

Pathogenic Hydrogel? A Novel-Entrapment Neuropathy Model Induced by Ultrasound-Guided Perineural Injections.

Entrapment neuropathy (EN) is a prevalent and debilitative condition caused by a complex pathogenesis that involves a chronic compression-edema-ischemia cascade and perineural adhesion that results in excessive shear stress during motion. Despite decades of research, an easily accessible and surgery-free animal model mimicking the mixed etiology is currently lacking, thus limiting our understanding of the disease and the development of effective therapies. In this proof-of-concept study, we used ultrasound-guided perineural injection of a methoxy poly(ethylene glycol)-b-Poly(lactide-co-glycoilide) carboxylic acid (mPEG-PLGA-BOX) hydrogel near the rat's sciatic nerve to induce EN, as confirmed sonographically, electrophysiologically, and histologically. The nerve that was injected with hydrogel appeared unevenly contoured and swollen proximally with slowed nerve conduction velocities across the injected segments, thus showing the compressive features of EN. Histology showed perineural cellular infiltration, deposition of irregular collagen fibers, and a possible early demyelination process, thus indicating the existence of adhesions. The novel method provides a surgery-free and cost-effective way to establish a small-animal model of EN that has mixed compression and adhesion features, thus facilitating the additional elucidation of the pathophysiology of EN and the search for promising treatments.

Socioeconomic factors predicting outcome in surgically treated carpal tunnel syndrome: a national registry-based study.

The study aimed to investigate socioeconomic factors in patients with carpal tunnel syndrome (CTS) and to evaluate their impact on outcome following open carpal tunnel release (OCTR). Data from the National Quality Register for Hand Surgery were combined with socioeconomic data (marital status, education level, earnings, migrant status, occupation, sick leave, unemployment, and social assistance) from Statistics Sweden to evaluate OCTRs performed from 2010 to 2016 (total 10,746 OCTRs). Patients completed QuickDASH (short version of Disabilities of Arm, Shoulder and Hand) questionnaires preoperatively (n = 3597) and at three (n = 2824) and 12 months (n = 2037) postoperatively. The effect of socioeconomic factors on QuickDASH scores was analyzed with linear regression analysis. Socioeconomically deprived patients scored higher on the QuickDASH on all occasions than patients with higher socioeconomic status. Being widowed, having a low education level, low earnings, immigrant status, frequent sick leave and dependence on social assistance all increased the postoperative QuickDASH score at 12 months. The change in total score for QuickDASH between preoperative and 12 months postoperatively did not vary between the groups. We conclude that such factors as being widowed, having a lower education level, low earnings, immigrant status, frequent sick leave and social assistance dependence are associated with more symptoms both before and after OCTR for CTS, but these factors do not affect the relative improvement in QuickDASH.

Effect of Age and Body Mass Index on Surgical Treatment Outcomes in Patients with Carpal Tunnel Syndrome.

AIM: To investigate the effect of age, diabetes mellitus, and body mass index (BMI) on the outcomes of carpal tunnel syndrome (CTS) surgery in patients with moderate CTS according to neurophysiological classification. MATERIAL AND METHODS: Postsurgical outcomes were evaluated via a nerve conduction study (NCS) six to nine months after the surgery. Patients were divided into two groups according to neurophysiological classification based on the findings of postsurgical NCS: patients with mild CTS (partial recovery) or normal NCS (complete recovery) were classified as surgical success, and patients with moderate to more severe CTS were defined as surgical failure. RESULTS: Forty-seven patients who underwent surgery for moderate CTS were included in the study. The mean age of the patients with surgical success (47.3 ± 10.9 years) was significantly lower than that of patients with surgical failure (54.3 ± 12.6 years; p=0.048). The mean BMI of the patients with surgical success (31.3 ± 4.03 kg/m2) was significantly lower than that of patients with surgical failure (36.75 ± 5.5 kg/m2; p < 0.001). Multivariate logistic regression analysis demonstrated that higher BMI (p=0.003) and older age (p=0.031) were independent prognostic factors for surgical failure. In addition, there was a statistically significant and strong correlation between postoperative CTS severity and BMI (rho=0.606, p < 0.001). CONCLUSION: Advanced age and high BMI negatively affect the success of surgical treatment in patients with CTS. Ensuring weight loss before surgery in CTS patients who have high BMI may increase the probability of treatment success.

Extracorporeal shock wave therapy versus local corticosteroid injection for the treatment of carpal tunnel syndrome: a meta-analysis.

BACKGROUND: Many studies have demonstrated the effectiveness of extracorporeal shock wave therapy (ESWT) and local corticosteroid injection (LCI) for the treatment of carpal tunnel syndrome (CTS), and some studies showed that the effect of ESWT was superior to LCI. We performed this meta-analysis to compare the clinical effects across the two therapies. METHODS: Relevant randomized controlled trials (RCTs) comparing ESWT and LCI for the treatment of CTS were searched in electronic database. The Cochrane risk bias tool was used for quality assessment. After data extraction and quality assessment of the included studies, a meta-analysis was performed using RevMan 5.3 software. Mean differences (MDs), odds ratios (ORs), and 95% confidence intervals (CIs) were analyzed. The protocol for this systematic review was registered on INPLASY (202080025) and is available in full on the inplasy.com ( https://doi.org/10.37766/inplasy2020.8.0025 ) RESULTS: A total of 5 RCT studies with 204 patients were included from the electronic database. The meta-analysis results showed that two therapies were not significantly different in terms of visual analog scale (VAS) score (P = 0.65), Boston Carpal Tunnel Questionnaire (BQ) score (P = 0.14), sensory distal latency (P = 0.66), and nerve conduction velocity (NCV) of the sensory nerve (P = 0.06). There were significant differences between the results of motor distal latency (P < 0.0001), compound muscle action potential (CMAP) amplitude (P < 0.00001), and sensory nerve action potential (SNAP) amplitude (P = 0.004). CONCLUSIONS: In terms of pain relief and function improvement, the effects of ESWT and LCI are not significantly different. In terms of electrophysiological parameters, LCI has a stronger effect on shortening motor distal latency; ESWT is superior to LCI in improving action potential amplitude. ESWT is a noninvasive treatment with fewer complications and greater patient safety. In light of the heterogeneity and limitations, these conclusions require further research for definitive conclusions to be drawn.

Assessment of grip-motion characteristics in carpal tunnel syndrome patients using a novel finger grip dynamometer system.

BACKGROUND: Grip strength measurement is widely used in daily medical practice, and it has been reported that the grip strength decreases in patients with carpal tunnel syndrome (CTS). However, conventional grip dynamometers evaluate only the maximum power of total grip strength and cannot measure the time course of grip motion. In this report, we aimed to determine the grip characteristics of CTS patients by measuring the time course of each finger's grip motion and to analyze the relationship between finger grip strength and subjective symptoms using this new grip system. METHODS: The grip strength of each finger was measured using the new grip system that has four pressure sensors on the grip parts of each finger of the Smedley grip dynamometer. We analyzed the time course of grip motion and relationship between finger grip strength and subjective symptoms in 104 volunteer and 51 CTS hands. The Japanese Society for Surgery of the Hand version of the Carpal Tunnel Syndrome Instrument (CTSI-JSSH) and the Disability of Arm, Shoulder, and Hand questionnaire (DASH) were used as subjective evaluation scores. RESULTS: In the CTS group, the grip time with the index, middle, and ring fingers was longer, and the time at which strength was lost after reaching the maximum was earlier. Patients with severe subjective symptoms tended to not use the index and middle fingers during grip motion. CONCLUSIONS: This new system that measures each finger's grip strength at one time and record the time course of grip motion could quantify a patient's symptoms easily and objectively, which may contribute to the evaluation of hand function.

Quality of electrodiagnostic testing for carpal tunnel syndrome: adherence to quality measures.

INTRODUCTION: Research has shown that quality of health-care services is often suboptimal. Little is known about the quality of electrodiagnostic testing. METHODS: We prospectively recruited 477 adults with workers' compensation claims for carpal tunnel syndrome (CTS) from 30 occupational health clinics and evaluated whether electrodiagnostic testing adhered to five process-oriented quality measures. RESULTS: Among patients who had surgery for CTS, nearly all underwent recommended preoperative electrodiagnostic testing (measure #1, 170 of 174, 97.7%). Most electrodiagnostic tests included essential components (measure #2, 295 of 379, 77.8%). However, few reports documented skin temperature (measure #3, 93 of 379, 24.5%) and criteria were seldom met for interpreting test findings as consistent with CTS (measure #4, 41 of 284, 14.4%) or "severe" CTS (measure #5, 8 of 46, 17.4%). DISCUSSION: Most patients underwent testing before surgery, but test quality was often suboptimal. This work lays the groundwork for future efforts to monitor and improve the quality of electrodiagnostic testing for CTS.

Screening for Carpal Tunnel Syndrome in Patients With Mucopolysaccharidosis.

Mucopolysaccharidoses (MPSs) are a group of rare lysosomal storage diseases with multisystem manifestations, including carpal tunnel syndrome (CTS). This study comprised a systematic review of literature and hospital guidelines addressing the method and frequency of screening for carpal tunnel syndrome in mucopolysaccharidosis patients and a review of carpal tunnel syndrome in patients seen in the multidisciplinary mucopolysaccharidosis clinic of a pediatric hospital, in order to develop screening recommendations. The literature reported the importance of routine carpal tunnel syndrome screening from early childhood in patients with mucopolysaccharidosis I, II, IV, and VI. Screening methods included physical examination, nerve conduction studies, electromyography, and ultrasonography. Ten of 20 mucopolysaccharidosis patients in our series underwent carpal tunnel syndrome surgery. Given the high incidence of carpal tunnel syndrome at a young age in mucopolysaccharidosis, the authors recommend performing physical examination and obtaining patient and caregiver history for carpal tunnel syndrome every 6 months from the time of mucopolysaccharidosis diagnosis, supplemented by annual nerve conduction studies in cases with poor history or equivocal examination.

Using Carpal Tunnel Questionnaire in clinical practice: A systematic review of its measurement properties.

INTRODUCTION: Carpal Tunnel Questionnaire (CTQ) is widely used for assessing condition-specific impairments in individuals with carpal tunnel syndrome (CTS) or for assessing outcomes after carpal tunnel surgery (carpal tunnel release [CTR]). A systematic review of its measurement properties can greatly facilitate its evidence-based use in clinical practice. The purpose of this study was to systematically locate, appraise, and synthesize the evidence concerning the reliability, responsiveness, validity, minimal detectable change (MDC), and minimal clinically important difference (MCID) for the CTQ and its scales. STUDY DESIGN: This is a systematic review of measurement properties. METHODS: Using predefined keywords, PubMed, CINAHL, PsychInfo, and ProQuest were searched to locate primary studies that assessed measurement properties of the CTQ. The methodological quality of the included studies was assessed using a standardized tool. Data concerning the measurement properties were extracted and synthesized. The pooled estimates for the indices of test-retest reliability, standard error of measurement, responsiveness, MDC, and MCID were calculated from the included studies. RESULTS: A total of 34 articles were deemed eligible and included in this review. The methodological quality of these 34 studies was generally good. Most studies suggested that the CTQ and its scales had good test-retest reliability and internal consistency. However, few studies found that the Symptom Severity Scale had more than one factor. The responsiveness of the CTQ and its scales was excellent across the studies. The pooled estimates for the MDC90 and MCID for Symptom Severity Scale/Functional Status Scale were 0.72/0.79 and 1.05/1.13, respectively. DISCUSSION: The results of this review support the use of CTQ and its scales in assessing conditions-specific impairments in individuals with CTS or after CTR. However, an effort should be made to review and modify the content of the symptom severity scale due to multiple reports challenging its unidimensional structure. CONCLUSIONS: The totality of evidence emerging from this systematic review suggests that the CTQ and its scales provide reliable and valid estimate of impairments resulting from CTS or after CTR.

Comparison of two approaches for carpal tunnel release: Extended versus mini-open technique.

OBJECTIVES: This study aims to describe a retrospective study using prospectively gathered data to compare mini-open and extended open release techniques for moderate to severe carpal tunnel syndrome (CTS). PATIENTS AND METHODS: The data of 198 consecutive patients (139 males, 59 females; mean age 57.0±4.5 years; range, 44 to 75 years) treated for CPS were used. For matching, age, gender and severity of the compression, the Greathouse Ernst Halle Schaffer neurophysiological classification system was used. After matching, 63 observations in each group (group 1: mini-open and group 2: extended open) were used for analysis. A Jamar hydraulic hand dynamometer was used to measure pre- and postoperative third month grip strengths. The key pinch test was performed also at third month. Patients completed the Boston Carpal Tunnel Questionnaire at the last follow-up. RESULTS: Symptom severity and functional status were improved up to half fold in both groups at final follow-up; however, there was no statistically significant clinical difference between the groups (p>0.05). There were totally six patients with paresthesia symptoms (three in each group; 4.7%), which improved in three months. Eight patients (6.3%, one in group 1 and seven in group 2, p=0.032) had dysesthesia and pillar pain. CONCLUSION: Mini-open and extended open carpal tunnel release have similar clinical outcomes without any major complications.

Postoperative diagnostic potentials of median nerve strain and applied pressure measurement after carpal tunnel release.

BAKGROUND: The objective of this study is to investigate the prognostic values of median nerve strain and applied pressure measurement for the assessment of clinical recovery after carpal tunnel release. METHODS: Forty-five wrists, from 45 idiopathic carpal tunnel syndrome patients who treated with open carpal tunnel release, were evaluated by ultrasound. Median nerve strain, pressure applied to the skin, and ratio of pressure-strain were measured at the proximal part of the carpal tunnel. In addition, distal latencies in the motor and sensory nerve conductions studies and cross-sectional area of median nerve were measured. The parameters were compared before and after the open carpal tunnel release. According to patient recovery, the receiver operating characteristic curves were generated to evaluate the prognostic values of the parameters. The areas under the receiver operating characteristic curves were compared among parameters. RESULTS: There was a significant increase in the median nerve strain, and significant decreases in the pressure applied to the skin and ratio of pressure-strain after carpal tunnel release (P < 0.01). There were significant decreases in the distal latencies and the cross-sectional area after carpal tunnel release (P < 0.01). The areas under the curves were 0.689, 0.773, 0.811, 0.668, 0.637, and 0.562 for the pressure, strain, pressure-strain ratio, motor latency, sensory latency, and area, respectively. CONCLUSIONS: The results suggest that elasticity of the median nerve and pressure around the nerve recover quickly after carpal tunnel release. Pressure-strain ratio was the most reliable parameter to reflect clinical recovery. The measurement of strain and applied pressure can be useful indicators to evaluate effectiveness of the carpal tunnel release. TRIAL REGISTRATION: Registered as NCT04027998 at ClinicalTrials.gov. Retrospectively registered on July 22, 2019.

A Comparison of PROMIS Physical Function and Pain Interference Scores in Patients With Carpal Tunnel Syndrome: Research Collection Versus Routine Clinical Collection.

Background: There is a concern that patients may answer patient-reported outcome (PRO) questionnaires differently depending on the purpose-clinical care or research (eg, "Hawthorne effect"). We sought to determine whether Patient-Reported Outcomes Management Information System (PROMIS) scores differ at the same clinic visit based on whether a patient was completing the PRO tool for study or clinical care purposes. Methods: Patients presenting to one surgeon at an academic medical center hand clinic were asked to complete PROMIS Physical Function (PF) and Pain Interference (PI) questionnaires as part of routine care. Those diagnosed with carpal tunnel syndrome from February 2015 to April 2017 were then asked to participate in a clinical research project, which had them complete PROMIS PF and PROMIS PI again. Data from those who completed both routine and research PROs at each visit were compared. Between the 2 settings, test-retest reliability was determined using Pearson correlation coefficients (r), and internal consistency was evaluated using Cronbach α. Results: A total of 128 unique office visits representing 67 patients fit our inclusion criteria. There was a strong correlation between PROMIS PF and PI in the research and patient care setting (PF: r = 0.82, P < .01; PI: r = 0.83, P < .01). Both domains had a Cronbach α of 0.90. The PROMIS PF scores were not different between the 2 groups (P = .19), but the PROMIS PI scores were slightly different (P < .01). Conclusions: Patients appear to be consistent when completing PROMIS for both clinical care and research, supporting the idea that data obtained in either setting are generalizable and appropriate for research purposes.

Visualization of electrophysiological activity at the carpal tunnel area using magnetoneurography.

OBJECTIVE: To establish a noninvasive method to measure the neuromagnetic fields of the median nerve at the carpal tunnel after electrical digital nerve stimulation and evaluate peripheral nerve function. METHODS: Using a vector-type biomagnetometer system with a superconducting quantum interference device, neuromagnetic fields at the carpal tunnel were recorded after electrical stimulation of the index or middle digital nerve in five healthy volunteers. A novel technique for removing stimulus-induced artifacts was applied, and current distributions were calculated using a spatial filter algorithm and superimposed on X-ray. RESULTS: A neuromagnetic field propagating from the palm to the carpal tunnel was observed in all participants. Current distributions estimated from the magnetic fields had five components: leading and trailing components parallel to the conduction pathway, outward current preceding the leading component, inward currents between the leading and trailing components, and outward current following the trailing component. The conduction velocity and peak latency of the inward current agreed well with those of sensory nerve action potentials. CONCLUSION: Removing stimulus-induced artifacts enabled magnetoneurography to noninvasively visualize with high spatial resolution the electrophysiological neural activity from the palm to the carpal tunnel. SIGNIFICANCE: This is the first report of using magnetoneurography to visualize electrophysiological nerve activity at the palm and carpal tunnel.

Differences in characteristics of carpal tunnel syndrome between male and female patients.

BACKGROUND: Sex difference is known to be a risk factor of carpal tunnel syndrome. However, sex differences with regard to the clinical presentation of carpal tunnel syndrome have not received much attention. Thus, this study aimed to detect any difference in the characteristics of carpal tunnel syndrome between male and female and thereby add new insights into disease prevention. METHODS: A total of 647 patients (male 193 hands and female 454 hands) with carpal tunnel syndrome who underwent endoscopic or open carpal tunnel release were retrospectively reviewed. The average age at time of surgery was 66 years. Clinical and electrophysiological data of all patients were collected. Six medical conditions, including trigger finger, diabetes mellitus, hemodialysis, hyperlipidemia, hypertension, and obesity were also investigated. RESULTS: A significant difference was found in the distribution of comorbidities between the male and female groups. Particularly, the prevalence of diabetes mellitus, hemodialysis, and hypertension were significantly higher in the male group than in the female group. Meanwhile, the presence of thenar muscle atrophy was significantly higher in the female group than in the male group. CONCLUSIONS: Women are more likely to experience carpal tunnel syndrome even though they have no comorbidities. We suggest that carpal tunnel syndrome especially in male patients may be reduced by early intervention for diabetes mellitus. Prospective studies are needed to validate the causal relationship between diabetes mellitus and carpal tunnel syndrome.