S35. Forearm Mixed Median Nerve Action Potential (MNAP): Reference values, influence of carpal tunnel syndrome, and its application in detection of proximal median neuropathy

ABSTRACTWe present a case of carpal tunnel syndrome (CTS) due to compression of the median nerve within the carpal tunnel, caused by cysticercosis. Nerve conduction studies revealed severe CTS. Magnetic resonance imaging suggested an inflammatory mass compressing the median nerve in carpal tunnel. The histological diagnosis was consistent with cysticercosis. The case resolved with conservative treatment. Such solitary presentation of entrapment median neuropathy as CTS caused by cysticercosis is extremely rare. To our knowledge, this is the only case of its kind reported in literature till date.

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Comparison of Borderline Ultrasound and Nerve Conduction Studies for Carpal Tunnel Syndrome

Hand ◽

10.1177/1558944720964963 ◽

2020 ◽

pp. 155894472096496

Author(s):

Cory Demino ◽

John R. Fowler

Keyword(s):

Carpal Tunnel Syndrome ◽

Median Nerve ◽

Carpal Tunnel ◽

Nerve Conduction ◽

Nerve Conduction Studies ◽

Threshold Values ◽

Cutoff Values ◽

Number Of Patients ◽

Tunnel Syndrome ◽

Median Neuropathy

Background Choosing cutoff values for nerve conduction studies (NCS) and ultrasound cross-sectional area (CSA) in the diagnosis of carpal tunnel syndrome (CTS) is critical in determining the diagnostic accuracy of the tests. The goals of this study were to: (1) determine the sensitivity and specificity of various electrodiagnostic and ultrasound threshold values for diagnosis of CTS; and (2) determine the number of hands that underwent NCS and ultrasound that were within 10% of threshold values. Methods A total of 309 hands of 235 patients were included in this study. Diagnosis of median neuropathy was made based on NCS by the independent physician performing the NCS. Criteria analyzed included distal motor latency of 4.4+ ms, distal sensory latency of 3.6+ ms, difference in median-ulnar mixed nerve palmar latency of 0.4+ ms, and CSA of the median nerve of 10+ mm2. Results Median neuropathy was diagnosed in 235 hands, whereas 74 hands were found not to have median neuropathy. Overall, 141 hands (46%) had at least 1 of the 3 electrodiagnostic variables within 10% of the diagnostic cutoff values, and 137 hands (44%) had a median nerve CSA within 10% of 10 mm2. By performing ultrasound in addition to NCS for each patient, an additional 65 hands (21%) had a definitive diagnosis on at least 1 of the 2 diagnostic modalities. Conclusions Ultrasound and NCS yielded a similar number of patients within 10% of their diagnostic threshold values. When used together, the number of patients with a nonborderline diagnosis on at least 1 diagnostic modality was increased substantially.

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31. Amplitude of sensory nerve action potential and transcarpal latency in carpal tunnel syndrome

Clinical Neurophysiology ◽

10.1016/j.clinph.2007.11.081 ◽

2008 ◽

Vol 119 (3) ◽

pp. e36

Author(s):

H. Kwon ◽

D. Kim ◽

K. Ha

Keyword(s):

Carpal Tunnel Syndrome ◽

Action Potential ◽

Carpal Tunnel ◽

Sensory Nerve ◽

Sensory Nerve Action Potential ◽

Nerve Action ◽

Sensory Nerve Action ◽

Tunnel Syndrome

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PO31-FR-21 Carpal tunnel syndrome: correlation between hand dominance and median compound sensory nerve action potential abnormalities

Journal of the Neurological Sciences ◽

10.1016/s0022-510x(09)71239-0 ◽

2009 ◽

Vol 285 ◽

pp. S326 ◽

Cited By ~ 1

Author(s):

A.S. Wee ◽

S.D. Abernathy

Keyword(s):

Carpal Tunnel Syndrome ◽

Action Potential ◽

Carpal Tunnel ◽

Sensory Nerve ◽

Hand Dominance ◽

Sensory Nerve Action Potential ◽

Nerve Action ◽

Sensory Nerve Action ◽

Tunnel Syndrome

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The Effectiveness of Ultrasound-Guided Steroid Injection Combined with Miniscalpel-Needle Release in the Treatment of Carpal Tunnel Syndrome vs. Steroid Injection Alone: A Randomized Controlled Study

BioMed Research International ◽

10.1155/2019/9498656 ◽

2019 ◽

Vol 2019 ◽

pp. 1-9 ◽

Cited By ~ 1

Author(s):

Subo Zhang ◽

Fei Wang ◽

Songjian Ke ◽

Caina Lin ◽

Cuicui Liu ◽

...

Keyword(s):

Carpal Tunnel Syndrome ◽

Action Potential ◽

Median Nerve ◽

Carpal Tunnel ◽

Steroid Injection ◽

Sensory Nerve ◽

Controlled Study ◽

Injection Group ◽

Tunnel Syndrome ◽

Release Group

Objectives. Carpal tunnel syndrome (CTS) is one of the most common nerve entrapment syndromes, which has a serious impact on patients’ work and life. The most effective conservative treatment is steroid injection but its long-term efficacy is still not satisfactory. The aim of this study was to evaluate the effectiveness of steroid injection combined with miniscalpel-needle (MSN) release for treatment of CTS under ultrasound guidance versus steroid injection alone. We hypothesized that combined therapy could be more beneficial. Methods. Fifty-one patients with CTS were randomly allocated into two groups, namely, steroid injection combined with MSN release group and steroid injection group. The therapeutic effectiveness was evaluated using Boston Carpal Tunnel Questionnaire (BCTQ), cross-sectional area (CSA) of the median nerve, and four electrophysiological parameters, including distal motor latency (DML), compound muscle action potential (CMAP), sensory nerve action potential (SNAP), and sensory nerve conduction velocity (SNCV) at baseline, 4 and 12 weeks after treatment. Results. Compared with baseline, all the parameters in both groups showed statistically significant improvement at week 4 and week 12 follow-up, respectively (P<0.05). When compared with steroid injection group, the outcomes including BCTQ, DML, CMAP, SNCV, and CSA of the median nerve were significantly better in steroid injection combined with MSN release group at week 12 after treatment (P<0.05). Conclusions. The effectiveness of steroid injection combined with MSN release for CTS is superior to that of steroid injection alone, which may have important implications for future clinical practice. This Chinese clinical trial is registered with ChiCTR1800014530.

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Cross-sectional Area of the Median Nerve Before Revision Carpal Tunnel Release—A Cross-sectional Study

Operative Neurosurgery ◽

10.1093/ons/opx079 ◽

2017 ◽

Vol 14 (1) ◽

pp. 20-25 ◽

Cited By ~ 3

Author(s):

Stephan Duetzmann ◽

Suleyman Tas ◽

Volker Seifert ◽

Gerhard Marquardt ◽

Thomas Dombert ◽

...

Keyword(s):

Carpal Tunnel Syndrome ◽

Median Nerve ◽

Reference Values ◽

Carpal Tunnel ◽

Cross Sectional Area ◽

Sectional Area ◽

Cross Sectional ◽

Large Patient ◽

Tunnel Syndrome ◽

The Mean

Abstract BACKGROUND High-resolution ultrasound can be used for diagnosis of carpal tunnel syndrome with an equal accuracy to electrodiagnostic studies. Up to date there has been no investigation published that examined the median nerve in a large patient cohort with recurrent or persistent symptoms. Reference and cutoff values are lacking. OBJECTIVE To provide reference values for detection of ongoing or recurrent compression in patients with recurring or persisting symptoms in carpal tunnel syndrome. METHODS One hundred and sixteen patients undergoing revision decompression of the median nerve at the carpal tunnel between January 2010 and October 2015 were studied retrospectively to determine the cross-sectional area of the median nerve at the wrist by the technique of neurosonography. RESULTS In cases of insufficient primary release, the mean cross-sectional area was 20.0 mm2 preop. In cases of scar or synovitis, the mean cross-sectional area was 17.0 mm2 (significantly less than in cases of insufficient primary release, P = .008). Compared to successfully operated patients with de novo carpal tunnel syndrome (n = 74), a cutoff value of 14.5 mm2 yielded a sensitivity of 78% and a specificity of 97% to diagnose ongoing or recurrent compression in case of a typical clinical presentation of ongoing or recurrent symptoms (tested via comparison of patients who are symptom free vs patients with symptoms). CONCLUSION For the first time, we provide reference values in patients with recurring or persisting symptoms in carpal tunnel syndrome based on a large patient population. Ultrasound can aid in the evaluation of patients with entrapment neuropathy of the median nerve and recurring or persisting symptoms.

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Prolonged distal motor latency of median nerve does not improve diagnostic accuracy for CIDP

Journal of Neurology ◽

10.1007/s00415-021-10672-w ◽

2021 ◽

Author(s):

Emanuele Spina ◽

Pietro Emiliano Doneddu ◽

Giuseppe Liberatore ◽

Dario Cocito ◽

Raffaella Fazio ◽

...

Keyword(s):

Carpal Tunnel Syndrome ◽

Diagnostic Accuracy ◽

Median Nerve ◽

Carpal Tunnel ◽

Chronic Inflammatory Demyelinating Polyneuropathy ◽

Distal Motor Latency ◽

Motor Latency ◽

Inflammatory Demyelinating Polyneuropathy ◽

Tunnel Syndrome ◽

Median Neuropathy

AbstractCompression of the median nerve at the carpal tunnel can give demyelinating features and result in distal motor latency (DML) prolongation fulfilling the EFNS/PNS demyelinating criteria for chronic inflammatory demyelinating polyneuropathy (CIDP). Accordingly, being carpal tunnel syndrome (CTS) common in the general population, the EFNS/PNS guidelines recommend excluding the DML of the median nerve when DML prolongation may be consistent with median neuropathy at the wrist from CTS. The main aims of this study were to verify whether the inclusion of DML of the median nerve (when consistent with CTS) could improve electrophysiological diagnostic accuracy for CIDP and if the median nerve at the carpal tunnel was more prone to demyelination. We analyzed electrophysiological data from 499 patients included consecutively into the Italian CIDP Database. According to the EFNS/PNS criteria, 352 patients had a definite, 10 a probable, and 57 a possible diagnosis of CIDP, while 80 were not fulfilling the diagnostic criteria. The inclusion of DML prolongation of median nerve did not improve significantly the diagnostic accuracy for CIDP; overall diagnostic class changed in 6 out of 499 patients (1.2%) and electrodiagnostic class of CIDP changed from not fulfilling to possible in only 2 patients (2.5% of not-fulfilling patients). In conclusion, we can infer that excluding DML prolongation of median nerve does not increase the risk of missing a diagnosis of CIDP thus corroborating the current EFNS/PNS criteria.

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