Análisis de los parámetros ecográficos descritos en el estudio del síndrome del túnel del carpo. Una revisión sistemática / Analysis of the echographic parameters described in the study of carpal tunnel syndrome: A systematic review

El síndrome del túnel del carpo (STC) es la mononeuropatía por atrapamiento más frecuente; el diagnóstico se establece mediante pruebas electrodiagnósticas con un número sustancial de falsos positivos/negativos. Presentamos la siguiente revisión sistemática, cuyo objetivo es analizar la literatura más reciente en relación con los parámetros ecográficos descritos para estudiar el STC. Seleccionamos estudios que evaluasen parámetros ecográficos en pacientes con sospecha clínica, siguiendo las recomendaciones del manual Cochrane; incluimos revisiones sistemáticas, metaanálisis, estudios caso-control y de pruebas diagnósticas, valorando estudios retrospectivos y revisiones bibliográficas con buena calidad metodológica. La revisión se hizo de artículos publicados entre 2005-2019. Incluimos 8 artículos (2 revisiones sistemáticas/metaanálisis, 2 estudios caso-control, un estudio de pruebas diagnósticas, 2 revisiones literarias y un estudio retrospectivo). Los parámetros analizados fueron el área de sección transversa del nervio mediano, el índice muñeca-antebrazo, el índice entrada-salida, el rango de adelgazamiento del nervio mediano, el abombamiento del retináculo flexor y la vascularización/movilidad. La evidencia actual permite afirmar que la ecografía tiene utilidad en el cribado del STC.(AU)

Carpal tunnel syndrome (CTS) is the most common entrapment mononeuropathy; the diagnosis is established by electrodiagnostic tests with until 34% of false positives/negatives. We present the following systematic review which objective is to analyze the most recent literature related to the ultrasound parameters described to study CTS. We selected studies that evaluated ultrasound parameters in patients with clinical suspicion following the Cochrane manual's recommendations. We include systematic reviews, meta-analyses, case–control studies and diagnostic tests, evaluating retrospective studies and bibliographic reviews with proper methodological quality. Articles published between 2005 and 2019. We included eight articles (two systematic reviews/meta-analyses, two case–control studies, one diagnostic test study, two literature reviews, and one retrospective). The parameters analyzed were cross-sectional area, wrist–forearm index, entry–exit index, thinning range, palmar bowing of the flexor retinaculum, and vascularity/mobility. Current evidence allows us to affirm that ultrasound is useful in screening for CTS.(AU)

[Analysis of the echographic parameters described in the study of carpal tunnel syndrome: A systematic review]. / Análisis de los parámetros ecográficos descritos en el estudio del síndrome del túnel del carpo. Una revisión sistemática.

Carpal tunnel syndrome (CTS) is the most common entrapment mononeuropathy; the diagnosis is established by electrodiagnostic tests with until 34% of false positives/negatives. We present the following systematic review which objective is to analyze the most recent literature related to the ultrasound parameters described to study CTS. We selected studies that evaluated ultrasound parameters in patients with clinical suspicion following the Cochrane manual's recommendations. We include systematic reviews, meta-analyses, case-control studies and diagnostic tests, evaluating retrospective studies and bibliographic reviews with proper methodological quality. Articles published between 2005 and 2019. We included eight articles (two systematic reviews/meta-analyses, two case-control studies, one diagnostic test study, two literature reviews, and one retrospective). The parameters analyzed were cross-sectional area, wrist-forearm index, entry-exit index, thinning range, palmar bowing of the flexor retinaculum, and vascularity/mobility. Current evidence allows us to affirm that ultrasound is useful in screening for CTS.

Diagnostic utility of anteroposterior measurements of the median nerve on sagittal ultrasonographic images and their correlation with clinical findings in carpal tunnel syndrome.

PURPOSE: To investigate the efficacy of sagittal ultrasonography of the median nerve in diagnosing carpal tunnel syndrome (CTS). METHODS: Seventy-six hands with idiopathic CTS and 80 hands of asymptomatic subjects were included. All patients with CTS underwent ultrasonographic examination, electrodiagnostic testing, and CTS-6 assessment. In the sagittal ultrasonographic examination, the maximum and minimum median nerve diameters (MNDs) were measured at the proximal and distal ends of the carpal tunnel, respectively. The median nerve stenosis rate (MNSR) was computed as (1 - minimum MND/maximum MND) × 100 (%). The cross-sectional area (CSA) of the median nerve at the level of the pisiform was measured. RESULTS: In the sagittal ultrasonographic examination, the mean maximum MNDs were 0.252 cm and 0.202 cm, mean minimum MNDs were 0.145 cm and 0.165 cm, and mean MNSRs were 41.83% and 17.35% in the CTS and control groups, respectively; the mean maximum MND and MNSR were considerably larger in the CTS group. The maximum MND and MNSR were correlated with the electrodiagnostic testing results and CTS-6 score. The MNSR with a cut-off value of 34.0% had a higher sensitivity and specificity than the CSA in diagnosing CTS. CONCLUSIONS: Sagittal ultrasonographic examination is useful in diagnosing CTS.

A Comparative Analysis Between Ultrasound and Electromyographic and Nerve Conduction Studies in Diagnosing Carpal Tunnel Syndrome (CTS): A Systematic Review and Meta-Analysis.

Carpal tunnel syndrome (CTS) is the most common upper extremity neuropathy. The disease initially manifests as a sensory disorder in the form of paresthesia, numbness, or tingling of the fingers. The diagnosis is usually made based on history and clinical symptoms, which are confirmed using nerve conduction studies (NCS) and electromyography. More recently, ultrasound has gained more use in CTS diagnosis due to its advantages, which include patients' comfort during diagnosis, better visualization of anatomy and nerve forms directly, and cost-effectiveness. However, a literature review shows that the diagnostic accuracy of ultrasound over NCS is still in question; therefore, the present systematic review was carried out to compare the diagnostic accuracy of ultrasound to NCS and electromyography. A systematic literature search was performed on five electronic databases: PubMed, Medline, Web of Science, Embase, and Google Scholar. The search strategy limited the retrieval of literature published between 2000 and 2022. Of the 1098 articles retrieved from the electronic databases, only 12 met the inclusion criteria. A meta-analysis of outcomes from the included studies showed that the pooled sensitivity and specificity of the ultrasound were 0.80 (95% CI: 0.73, 0.88) and 0.90 (0.83, 0.96), respectively. On the other hand, combing the outcomes of electromyography and NCS resulted in sensitivity and specificity values of 0.89 (95% CI: 0.84, 0.95) and 0.77 (95% CI; 0.64, 0.90), respectively. The results show that ultrasound has comparable sensitivity and slightly higher specificity than NCS and electromyography; therefore, ultrasound can be used as an alternative diagnostic test for CTS. However, it cannot replace NCS and electromyography since more research needs to be done on doubtful and secondary cases of CTS.

Posterior Border Distance: An Effective Diagnostic Measurement for Carpal Tunnel Syndrome Using Ultrasonography.

Purpose The purpose of this study was to define posterior border distance (PBD), which represents an ultrasonographic diagnosing method of carpal tunnel syndrome (CTS), and to determine the reliability of PBD in comparison with electromyography (EMG) results. Methods Thirty-three patients (mean age: 51.8 ± 9.5 years; 27 females and six males) with CTS were included in this study. Ultrasonography (US) and EMG were performed under blinded conditions. PBD was evaluated by measuring the length of the perpendicular line between the posterior border of the median nerve and the line between the hook of the hamate and trapezoid tubercle. The cross-sectional area, anteroposterior (AP), and transverse diameter of the median nerve were measured. Control US was performed in 20 patients who were available at the first year postoperative follow-up and the results compared with preoperative US values. Correlation analyzes were performed to determine the relationship between electrodiagnostic results and ultrasonographic measurements. Results According to the results of preoperative and postoperative first-year US, there were statistically significant differences in the results of PBD (preoperative: 3.309±1.7472 mm, postoperative: 2.290±0.7867 mm p: 0.013) and AP diameter of the median nerve (preoperative: 3.012±0.7865 mm, postoperative: 2.680±0,5578 mm p: 0.017). There was no statistically significant difference in transverse diameter (preoperative: 6.585±1.9505 mm, postoperative: 6.955±2.2128 mm) and cross-sectional area (preoperative: 14.33±6.513 mm2, postoperative: 11.20±5.830 mm2) results (p>0.05). The cut-off value of PBD was ≥3.6 mm, it yielded 81.48% specificity and 83.33% sensitivity in the diagnosis of CTS. PBD was correlated with motor and sensory latency, anteromedial, and transverse diameter of the median nerve (p<0.05). There was no correlation between EMG values and the results of the cross-sectional area, transverse diameter, and AP diameter of the median nerve (p>0.05). Conclusion PBD is suggested as a reliable ultrasonographic measurement method for the diagnosis of CTS.

Borderline Nerve Conduction Velocities for Median Neuropathy at the Carpal Tunnel.

PURPOSE: Patient knowledge of the frequency with which electrodiagnostic testing (EDx) for suspected median neuropathy at the carpal tunnel addresses nuance in the distinction between normal and abnormal neurophysiology might help them make an informed decision about whether or not to have this test. We reviewed a large set of consecutive EDx for possible carpal tunnel syndrome (CTS) and associated medical records to determine (1) the percentage of EDx measurements within 10% of threshold values; (2) discordance between clinician and EDx diagnosis of CTS using diagnostic performance characteristics; and (3) demographic and disease characteristics independently associated with EDx diagnosis of median neuropathy at the carpal tunnel. METHODS: We retrospectively reviewed nerve conduction study (NCS) results of 537 consecutive patients evaluated for possible idiopathic median neuropathy at the carpal tunnel. We measured the number of patients within 10% of 3 NCS diagnostic thresholds; the diagnostic performance characteristics comparing clinician and EDx diagnosis; and patient and disease characteristics associated with EDx diagnosis of CTS. RESULTS: The 3 NCS parameters were within 10% of the threshold for diagnosis of median neuropathy at the carpal tunnel in 2.6% to 33% of patients. Overall, 76% of EDx results were interpreted as median neuropathy at the carpal tunnel, 19% as normal, and 5% as another diagnosis (eg, cervical radiculopathy). Patients with normal EDx were significantly younger, more likely not to report paresthesias/numbness, more likely to have prior normal EDx, and less likely to have had a previous contralateral carpal tunnel release. CONCLUSIONS: This data set reflecting management strategies for suspected CTS at a large institution confirms inherent diagnostic uncertainty, relatively strong concordance between clinician and EDx diagnosis, and the importance of focusing on paresthesia rather than pain. These findings support the use of clinical prediction rules and may help inform a patient's decision regarding whether or not to have EDx. TYPE OF STUDY/LEVEL OF EVIDENCE: Diagnostic III.

Lambert-Eaton Myasthenic syndrome: early diagnosis is key.

Lambert-Eaton myasthenic syndrome (LEMS) is an uncommon disorder of neuromuscular transmission with distinctive pathophysiological, clinical, electrophysiological and laboratory features. There are two forms of LEMS. The paraneoplastic (P-LEMS) form is associated with a malignant tumor that is most frequently a small cell lung carcinoma (SCLC), and the autoimmune (A-LEMS) form is often related to other dysimmune diseases. Approximately 90% of LEMS patients present antibodies against presynaptic membrane P/Q-type voltage-gated calcium channels (VGCC). These antibodies are directly implicated in the pathophysiology of the disorder, provoke reduced acetylcholine (ACh) at the nerve terminal and consequently lead to muscle weakness. LEMS is clinically characterized by proximal muscle weakness, autonomic dysfunction and areflexia. In clinically suspected cases, diagnoses are confirmed by serological and electrodiagnostic tests. The detection of P/Q-type VGCC antibodies is supportive when there is clinical suspicion but should be carefully interpreted in the absence of characteristic clinical or electrodiagnostic features. Typical electrodiagnostic findings (ie, reduced compound motor action potentials (CMAPs), significant decrements in the responses to low frequency stimulation and incremental responses after brief exercise or high-frequency stimulation) reflect the existence of a presynaptic transmission defect and are key confirmatory criteria. Diagnosis requires a high level of awareness and necessitates the initiation of a prompt screening and surveillance process to detect and treat malignant tumors. In clinically affected patients without cancer and after cancer treatment, symptomatic treatment with 3,4-diaminopyridine or immunosuppressive agents can significantly improve neurologic symptoms and the quality of life. We present a detailed review of LEMS with special emphasis on the pathophysiological mechanisms, clinical manifestation and diagnostic procedure.

Repetitive nerve stimulation test in myasthenic crisis.

INTRODUCTION: Herein we report our experience with the repetitive nerve stimulation (RNS) test in myasthenia gravis (MG) crisis. METHODS: The various parameters of the RNS tests in 26 patients with MG crisis were analyzed. RESULTS: In 18 (69%) patients, MG crisis is the first manifestation of MG. RNS tests were abnormal in 24 (92%) patients by decrement at low-rate stimulation in any of 4 tested muscles. Three patterns of abnormality were found: MG pattern (decrement at low-rate stimulation) in 23 patients; Lambert-Eaton myasthenic syndrome pattern in 1 patient; and cholinergic crisis pattern in 1 patient. DISCUSSION: During MG crisis, the RNS test can serve as a rapid and sensitive diagnostic tool for MG in a majority of patients. Muscle Nerve 59:544-544, 2019.

Raised intracranial pressure in Crouzon syndrome: incidence, causes, and management.

OBJECT Patients with Crouzon syndrome (CS) are at risk for developing raised intracranial pressure (ICP), which has the potential to impair both vision and neurocognitive development. For this reason, some experts recommend early prophylactic cranial vault expansion on the basis that if ICP is not currently raised, it is likely to become so. The aim of this study was to examine the justification for such a policy. This was done by analyzing the incidence, causes, and subsequent risk of recurrence in a series of patients with CS, in whom raised ICP was treated only after it had been diagnosed. METHODS This study was a retrospective review of the medical records and imaging data of patients with a clinical diagnosis of CS. RESULTS There were 49 patients in the study, of whom 30 (61.2%) developed at least 1 episode of raised ICP. First episodes occurred at an average age of 1.42 years and were attributable to craniocerebral disproportion/venous hypertension (19 patients), hydrocephalus (8 patients), and airway obstruction (3 patients). They were managed, respectively, by vault expansion, ventriculoperitoneal shunt insertion, and airway improvement. Fourteen of the 30 patients developed a second episode of raised ICP an average of 1.42 years after treatment for their initial episode, and 3 patients developed a third episode an average of 3.15 years after that. Causes of subsequent episodes of raised ICP often differed from previous episodes and required different management. Patients who were < 1 year old when the first episode was diagnosed were at increased risk of recurrence. CONCLUSIONS Although the incidence of raised ICP in CS is high, it did not occur in nearly 40% of children during the course of this study. The several possible causes of CS require different management and may vary from episode to episode. The authors recommend an expectant policy toward these children with careful clinical, ophthalmological, respiratory, and radiological monitoring for raised ICP, reserving intervention for when it has been detected and the appropriate treatment can be initiated.

Progression of carpal tunnel syndrome according to electrodiagnostic testing in nonoperatively treated patients.

BACKGROUND: This study tested the null hypothesis that nonoperatively treated patients would not show disease progression of carpal tunnel syndrome (CTS) over time according to median nerve distal motor latency (DML) on two electrodiagnostic tests. METHODS: This retrospective study analyzed sixty-two adult nonoperatively treated patients who were diagnosed with CTS confirmed by a minimum of two electrodiagnostic tests at our institution between December 2006 and October 2012. A Wilcoxon signed-rank test was conducted to test the difference between electrodiagnostic measurements between the first and last test. RESULTS: The mean time between the first and last electrodiagnostic test was 26±12 months (range, 12 to 55 months). The only electrodiagnostic measurement that increased significantly was the difference between median and ulnar DML on the same side (r=0.19, P=0.038). The time between the electrodiagnostic tests was significantly longer for patients with at least 10% worsening of the DML at the second test compared to cases of which the DML did not worsen or improve a minimum of 10% (P=0.015). CONCLUSIONS: There is evidence that-on average-idiopathic median neuropathy at the carpal tunnel slowly progresses over time, and this can be measured with electrodiagnostics, but studies with a much longer interval between electrodiagnostic tests may be needed to determine if it always progresses.

Changes in treatment plan for carpal tunnel syndrome based on electrodiagnostic test results.

This study evaluated how often the treatment plan for carpal tunnel syndrome (CTS) changed based on electrodiagnostic test results. Secondly, we assessed factors associated with a change in the treatment plan for CTS. One-hundred-and-thirty English-speaking adult patients underwent electrodiagnostic testing in a prospective cohort study. Treatment plan was recorded before and after testing. Treatment plan changed in 25 patients (19%) based on electrodiagnostic test results. The plan for operative treatment before testing decreased significantly after testing (83% versus 72%). The best logistic regression model for no change in treatment plan included a prolonged or non-recordable median distal sensory latency (normal, prolonged, or non-recordable), and explained 24% of the variation. For surgeons that manage CTS on the basis of objective pathophysiology rather than symptoms, electrodiagnostic test results often lead to changes in recommended treatment.

Electrodiagnostic Methods for Carpal Tunnel Syndrome Combined with Diabetic Polyneuropathy

OBJECTIVE: To find out the most useful method among three electrodiagnostic tests for carpal tunnel syndrome (CTS) in patients with diabetic peripheral polyneuropathy (PPN). METHOD: Eighty-three hands out of seventy-four patients who had diabetic PPN and tingling sensation in their hands were included in this study. They were divided into two groups: Group A, PPN with CTS; Group B, PPN only. Fifty-four hands with CTS in patients without diabetes were included as a control group (Group C). Another forty normal hands were also included as a healthy control group (Group D). Clinical and electrophysiologic information was gathered from those subjects. Sensitivity, specificity and receiver operating characteristic (ROC) curves of the three electrodiagnostic tests, namely, the difference between the median nerve latency to the second lumbrical muscle and the ulnar nerve latency to the second interosseous muscle (L-I difference), ratio of distoproximal latency in median sensory nerve (MW ratio), and difference of distoproximal latency in median sensory nerve (MW difference) to diagnose clinical CTS were obtained. RESULTS: The specificity of L-I difference as a diagnostic test for CTS was highest (87.0%). The area of ROC curve of L-I difference was also highest (0.949) among three different electrodiagnostic tests of CTS with diabetic PPN. CONCLUSION: We suggest that L-I difference as the most useful test with highest specificity for the diagnosis of CTS in the patients with diabetic PPN.

Predictive Value of Sensory Nerve Conduction in Carpal Tunnel Syndrome

OBJECTIVE: Electrodiagnostic test has shown diagnostic sensitivity and specificity in carpal tunnel syndrome(CTS). This study was to evaluate the correlation between clinical outcome of endoscopic carpal tunnel ligament release(ECTR) and the predictive value of sensory nerve conduction. METHODS: From January 1998 to December 2004, 87 patients (44 right hand, 37 left hand, 6 bilateral hands) with CTS who underwent ECTR were followed up in our hospital for an average of 2.4 months. We retrospectively analyzed the results with previous medical records. All patients underwent electrodiagnostic test and ECTR. The patients were divided into three groups according to the electrodiagnostic test results. Group (A) was normal sensory nerve response, Group (B) was slowing sensory response and Group (C) was no sensory response. Improvement of the symptom after ECTR was assessed using a visual analogue scale(VAS) score. RESULTS: Differences between the three groups on the correlation of severity of sensory potential and duration of preoperative symptoms were significant. The mean value of improved VAS scores for the three groups were 6.0+/-0.96 in the Group A, 6.11+/-0.48 in the Group B and 6.14+/-0.53 in the Group C. There was no statistically significant difference between the severity of sensory nerve response and improvement in VAS score after ECTR. Complications included a wound infection, a case of skin necrosis, and two patients with persistent symptoms without any improvement. CONCLUSION: Although electrodiagnostic test has been known to be useful, sensory nerve response is considered not to be a good prognostic value for carpal tunnel syndrome after ECTR.

Brachial Plexopathy Caused by Pancoast Tumor: A case report

Pancoast tumor is a specific lung carcinoma that has symptoms according to the location. It often involves the extrathoracic structure more than parenchyme of lung, that cause shoulder pain. A 61-years old man had been complaining of shoulder pain and limitation of range of motions of shoulder joint. Conservative management of the shoulder pain was not effective with physical therapy and injection therapy and the symptom of right upper extremity radiating pain had been aggravated. We had examination of the eletro-diagnostic test in 17 months after shoulder pain was developed. The findngs of the electrodiagnostic test was suspected as the injury of lower trunk of brachial plexus, so we had checked MRI on brachial view. The pancoast tumor was found in the extrathoracic region that invaded the lower trunk of the brachial plexus. The shoulder pain related with tumor was rare and could cause brachial plexopathy.

Electrodiagnostic Study on Neuropathies in String Players

OBJECTIVE: To determine the frequency, involved nerves and sites of entrapment neuropathy in string players. METHOD: The subjects were 24 string playing musicians and age matched 24 normal controls. Questionnaire, physical examination were taken in the musicians and the electrodiagnostic study was performed in both the musician and the control groups. Electrodiagnostic study included nerve conduction study of median and ulnar nerves. The distal motor latency, segmental motor conduction velocity, distal sensory latency, and amplitude of sensory nerve action potentials were measured. Each parameter of nerve conduction study was compared in two groups and was correlated to the string playing duration. RESULTS: Three musicians (12.5%) were diagnosed as entrapment neuropathy: One, left ulnar neuropathy at the elbow and the wrist and left median neuropathy at the wrist; Two, left ulnar neuropathy at the elbow. Ulnar motor conduction velocity of right forearm segment and left elbow segment were significantly reduced in the musicians compared to those of the controls (P<0.05). The distal sensory latency of left ulnar nerve was significantly prolonged in musicians compared to that of the controls (P<0.05). The string playing duration significantly correlated with the distal motor latency of right median nerve (R=0.632, P<0.05) and the distal sensory latency of left median nerve (R=0.518, P<0.05). CONCLUSIONS: These results suggest that some entrapment neuropathies could be developed due to cumulative trauma in string players. Elbow and wrist segment of left ulnar nerve, forearm segment of right ulnar nerve are possible sites of entrapment neuropathy in string players.

Polyneuropathy by Occupational Exposure to Acrylamide / 대한산업의학회지

Authors report a first Korean case of polyneuropathy in an acrylamide producing factory together with an environmental and epidemiologic survey for the ten workers of the same workplace and 46 workers in the production and manufacturing acrylamide in Ulsan, Korea. The case is 30 years old man who worked in the prcduction of the acrylamide for two years. In August, 1997, he had a weakness of the lower extremity with loss of body weight of 15 Kg which progressed to paresthesia of the limbs, the loss of vibration sense, difficulty in walking, speech disturbance, dysuria, constipation, difficulty in erection and swallowing difficulty. Neurologic examination showed a complete loss of vibration and position sense, and loss of deep tendon reflex in all the limbs. There was a contact dermatitis-like skin lesion on the feet. Electrodiagnostic test showed a generalized polyneuropathy of moderate degree involving motor and sensory component of peripheral and cranial nerves. After 8 months' cessation from exposure and supportive care, his symptoms were completely resolved, but abnormality in electrodiagnostic test and vibrotactile perception threshold still persisted, although much improved than before. There were 11 workers in the same workplace of the case, producing acrylamide by microorganism as a catalyst. Environmental monitoring of the workplace revealed air-borne concentration of the acrylamide to be from 0.05 to 0.23 mg/m(3) by personal sampling and from 7.65 to 11.65 mg/m(3) by area sampling during filter exchanging process, which far exceeds TLV-TWA of 0.03 mg/m(3). However acrylamide was not detected from the plasma of the workers. Symptom questionnaire showed a markedly higher complain of neurologic symptoms, compared to the workers of the other acrylamide producing companies. Electrodiagnostic test showed a several workers are in the lower normal range without definite abnormality. Vibrotactile perception threshold by Vibratron II showed a significantly increased threshold in the workers of the same workplace compared to the other acrylamide workers and significantly decreased test score of color vision compared to normal controls. After improvement of the production process and strict wearing of the protective device, most workers reported the improvement of clinical symptoms, but vibrotactile perception threshold was not improved. These result suggests the need for the effective environmental monitoring together with a periodic biological monitoring. Development of effective screening test is urgently needed to control and assess the skin absorption of acrylamide.