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Pruebas nerviosas y estudios de conducción nerviosa
What nerve conduction studies and EMG are, why they are done for carpal tunnel and other nerve problems, what to expect, and how accurate they are.
¿Qué es?¶
Las pruebas nerviosas miden lo bien que los nervios transmiten las señales eléctricas. Existen dos métodos eléctricos para comprobar el funcionamiento de los nervios, y ambos han demostrado ser útiles en la práctica [1]. La prueba principal se llama estudio de conducción nerviosa. Un pequeño aparato envía un impulso diminuto al nervio y registra a qué velocidad viaja la señal. Si un nervio está comprimido o dañado, la señal se ralentiza o se debilita.
Estas pruebas se utilizan sobre todo en el síndrome del túnel carpiano, en el que el nervio de la parte delantera de la muñeca está sometido a presión. Se consideran una parte indispensable de la valoración antes de operar esta afección [2]. La mayoría de los médicos no operan sin esta confirmación [3]. Las pruebas también pueden ayudar con otros problemas nerviosos, como la presión sobre el nervio a la altura del codo (síndrome del túnel cubital) [4].
Normalmente se le hará una segunda prueba en la misma visita. Para ello, se introduce una aguja fina en algunos músculos. Esta prueba comprueba lo bien que responden los músculos a los nervios que los controlan. En conjunto, se denominan estudios electrodiagnósticos, lo que simplemente significa pruebas que utilizan la electricidad para estudiar los nervios y los músculos.
Las pruebas funcionan porque los nervios transmiten señales igual que los cables conducen la corriente. Un nervio comprimido se comporta como un cable pellizcado, de modo que la señal que lo recorre se retrasa o se reduce. Los resultados dan una medida de lo afectado que está el nervio, y este es el mejor indicador disponible de la gravedad global de la enfermedad [5]. El valor de estas pruebas está en acertar con el diagnóstico y valorar su gravedad, más que en predecir cómo se sentirá usted después de la cirugía [6].
Conviene saber una cosa: una prueba normal no descarta el síndrome del túnel carpiano, porque la compresión del nervio puede ir y venir.
¿Funciona?¶
La respuesta sincera es que estas pruebas son buenas para algunas cosas y limitadas para otras. Son un complemento útil para comprobar si existe un síndrome del túnel carpiano, sobre todo cuando las pruebas habituales salen normales [7]. Un estudio sobre una prueba nerviosa especial observó que detectaba la afección en el 69% de los casos, y que todos los resultados positivos eran correctos. Cuando esa prueba se combinó con otra forma de medir la sensibilidad, detectó el 84% de los casos [8].
Las pruebas también ayudan a confirmar el diagnóstico antes de la cirugía. Cuando sus signos y síntomas apuntan a una presión de leve a moderada sobre el nervio y se está considerando la cirugía, las pruebas adicionales pueden aumentar la probabilidad de que la cirugía se dirija a un problema real y tratable [9]. Un estudio encontró una gran diferencia entre el número de personas diagnosticadas solo por los síntomas (73%) y el número confirmado mediante estas pruebas y la ecografía (51%) [10]. Esa diferencia es precisamente la razón por la que las pruebas son importantes: permiten distinguir quién tiene realmente un problema nervioso que la cirugía puede ayudar.
Tienen sus límites. La calidad de estas pruebas varía de un profesional a otro, y algunos informes dan más detalle que otros [11]. Los criterios para interpretarlas también necesitan una definición más precisa, para que los diagnósticos sean exactos y no se operen casos que no lo necesitan [12]. Y las pruebas no pueden decirle todo. Miden el nervio, no sus síntomas.
Algunos resultados son contradictorios. Los cambios en los resultados de las pruebas tras una inyección de corticoides no fueron significativos a los dos años [13]. Por otro lado, una buena respuesta a una inyección es una señal útil sobre cómo puede ir la cirugía [14]. Una de las medidas de las pruebas, llamada latencia motora distal, que es simplemente el tiempo que tarda la señal en llegar a un músculo, tiene cierto valor para predecir cómo le irá después de la cirugía [15].
Así pues, las pruebas funcionan bien como herramienta de diagnóstico. Son menos fiables como bola de cristal para predecir su recuperación.
¿Cuáles son los riesgos?¶
Las pruebas nerviosas son seguras, pero conviene que sepa qué esperar. El efecto más frecuente son las molestias durante la propia prueba. Los impulsos eléctricos se notan como pequeños golpecitos o punzadas. Si se introduce una aguja fina en un músculo, notará un pinchazo breve, y el músculo puede dolerle durante uno o dos días después. La versión de la prueba en el dedo anular es rápida y le supone un esfuerzo mínimo [16].
Los impulsos eléctricos no dejan efectos duraderos en la piel ni en los tejidos. Los impulsos son pequeños y atraviesan la piel sin dañarla. Si le hacen una prueba con aguja, las zonas de punción pueden quedar ligeramente sensibles y puede aparecer un pequeño moretón. Esto se resuelve por sí solo.
Los estudios no describen efectos en el resto del cuerpo, ni describen complicaciones raras pero graves de estas pruebas. Merece la pena decirlo con claridad: los estudios en los que se basa esta página informan de lo bien que las pruebas diagnostican y predicen, no de sus daños, por lo que la información que aquí se ofrece sobre riesgos graves es limitada.
Hay un riesgo que no es físico. Distintos profesionales pueden interpretar las pruebas de forma diferente, y algunos informes dan más detalle que otros [11]. Un informe que enumera pequeñas anomalías sin explicarlas puede llevar a una conclusión equivocada [17]. Los criterios para interpretar las pruebas también necesitan una definición más precisa, para que los diagnósticos sean exactos y no se operen casos que no lo necesitan [12]. Esto es lo principal que puede salir mal: no la prueba en sí, sino un diagnóstico basado en un informe incompleto o poco claro.
Si le han puesto una inyección de corticoides para el síndrome del túnel carpiano, los cambios en los resultados de las pruebas tras esa inyección no fueron significativos a los dos años [13]. Esto significa que la inyección no parece cambiar lo que muestran las pruebas a largo plazo, por lo que repetir la prueba después de una inyección debería seguir dando una imagen fiel de su nervio.
Pida a su médico o a la persona que le hace la prueba que le explique el informe. Una descripción clara de lo que encontró la prueba, y de lo que significa, forma parte de un buen resultado.
¿Es adecuado para usted?¶
Si sus síntomas apuntan a un síndrome del túnel carpiano y se plantea la cirugía, estas pruebas suelen formar parte del plan. La mayoría de los médicos no operan sin esta confirmación [3]. Las pruebas adicionales pueden aumentar la probabilidad de que la cirugía se dirija a un problema nervioso real y tratable [9]. Esto es importante, porque las pruebas aciertan con el diagnóstico y muestran la gravedad de la presión sobre el nervio [6].
Pueden ser menos útiles si sus síntomas son imprecisos o van y vienen. La compresión del nervio puede pasar desapercibida el día de la prueba. Un resultado normal no descarta el síndrome del túnel carpiano. Las pruebas tampoco pueden predecir cómo se sentirá después de la cirugía, así que son una herramienta para el diagnóstico, no una promesa sobre su recuperación [6].
La principal alternativa es la ecografía, que también puede comprobar si hay presión sobre el nervio [9]. Su médico puede proponerle una de ellas o ambas. Cada una tiene sus puntos fuertes, y la elección adecuada depende de sus síntomas y de la exploración.
Debe ser una decisión compartida con su médico. Pregunte qué se espera que muestre la prueba y qué ocurrirá si el resultado es normal. Si tiene preguntas sobre los riesgos de la propia prueba, lea el apartado anterior sobre los riesgos.
Conclusión¶
Si se está considerando la cirugía del síndrome del túnel carpiano, merece la pena hacerse estas pruebas. Confirman si la presión sobre el nervio es real y muestran su gravedad [6]. Las pruebas adicionales pueden aumentar la probabilidad de que la cirugía se dirija a un problema real y tratable [9]. Hágalas con expectativas realistas: las pruebas son buenas para el diagnóstico, pero no pueden predecir cómo se sentirá después de la cirugía [6]. La advertencia más importante es que un resultado normal no descarta el síndrome del túnel carpiano, porque la compresión del nervio puede ir y venir. Pida una explicación clara de su informe antes de tomar cualquier decisión.
Referencias¶
[1] Sensory threshold and conductance testing in nerve injuries. The Journal of Hand Surgery: Journal of the British Society for Surgery of the Hand. 1986. DOI: 10.1016/0266-7681(86)90252-4
[2] Correlation of Clinical Signs with Nerve Conduction Tests in the Diagnosis of Carpal Tunnel Syndrome. Journal of Hand Surgery. 1994. DOI: 10.1016/0266-7681(94)90244-5
[3] Current Practice in the Use of Nerve Conduction Studies in Carpal Tunnel Syndrome by Surgeons in the Netherlands. Journal of Hand Surgery (European Volume). 2007. DOI: 10.1016/j.jhse.2007.09.007
[4] Diagnosis of Ulnar Neuropathy at the Elbow Using Ultrasound — A Comparison to Electrophysiologic Studies. The Journal of Hand Surgery. 2023. DOI: 10.1016/j.jhsa.2023.08.014
[5] Use of nerve conduction studies in carpal tunnel syndrome. Journal of Hand Surgery (European Volume). 2023. DOI: 10.1177/17531934231191685
[6] Electrical studies as a prognostic factor in the surgical treatment of carpal tunnel syndrome. The Journal of Hand Surgery. 1996. DOI: 10.1016/s0363-5023(96)80384-4
[7] Provocative motor nerve conduction testing in presumptive carpal tunnel syndrome unconfirmed by traditional electrodiagnostic testing. The Journal of Hand Surgery. 1997. DOI: 10.1016/s0363-5023(97)80045-7
[8] The utility of portable nerve conduction testing for patients with carpal tunnel syndrome: A prospective clinical study. The Journal of Hand Surgery. 1992. DOI: 10.1016/0363-5023(92)90117-8
[9] Diagnosis of Mild-to-moderate Idiopathic Median Neuropathy at the Carpal Tunnel Based on Signs and Symptoms is Discordant From Diagnosis Based on Electrodiagnostic Studies and Ultrasound. Clinical Orthopaedics & Related Research. 2023. DOI: 10.1097/corr.0000000000002751
[10] CORR Insights®: Diagnosis of Mild-to-moderate Idiopathic Median Neuropathy at the Carpal Tunnel Based on Signs and Symptoms is Discordant From Diagnosis Based on Electrodiagnostic Studies and Ultrasound. Clinical Orthopaedics & Related Research. 2023. DOI: 10.1097/corr.0000000000002822
[11] Electrodiagnostic reports of median neuropathy at the wrist. The Journal of Hand Surgery. 1998. DOI: 10.1016/s0363-5023(98)80089-0
[12] Electrodiagnostic testing and carpal tunnel release outcome. The Journal of Hand Surgery. 1997. DOI: 10.1016/s0363-5023(05)80209-6
[13] Nerve Conduction Studies after Treatment for Carpal Tunnel Syndrome. Journal of Hand Surgery. 1992. DOI: 10.1016/0266-7681(92)90191-4
[14] Diagnostic and therapeutic value of carpal tunnel injection. The Journal of Hand Surgery. 1984. DOI: 10.1016/s0363-5023(84)80065-9
[15] Carpal Tunnel Syndrome: Neurophysiological Results of Surgery Based on Preoperative Electrodiagnostic Testing. Journal of Hand Surgery. 1997. DOI: 10.1016/s0266-7681(97)80355-5
[16] Relative slowing of the median antidromic sensory nerve conduction velocity to the ring finger in screening for carpal tunnel syndrome. The Journal of Hand Surgery. 2004. DOI: 10.1016/j.jhsa.2004.04.026
[17] Electrodiagnostic testing in hand surgery. The Journal of Hand Surgery. 1996. DOI: 10.1016/s0363-5023(96)80298-x
Evidence & references
This is the clinical evidence summary written for health professionals. It is technical, and it lists the research this page was built from. You do not need to read it to understand your treatment or to make a decision about it.
Overview¶
- Nerve conduction studies serve as a measure of impaired nerve function and are the best available indicator of overall disease severity with some prognostic value for surgical outcome [1].
- Nerve conduction studies are considered an indispensable part of the pre-operative evaluation for carpal tunnel syndrome [2].
- Provocative nerve conduction testing is a useful and simple addition to the overall evaluation of patients with carpal tunnel syndrome, particularly those with otherwise normal findings on traditional electrodiagnostic studies [3].
- The selection of an appropriate electrical screening test for peripheral nerve injury depends on the prevalence and seriousness of the target disease and the relative consequences of over- and underdiagnosis [4].
- The absence of any real difference in nerve conduction time between a working group with symptoms and a group with diagnosed carpal tunnel syndrome indicates a high probability that many participants with symptoms would have had abnormal findings on standard electrodiagnostic tests [5].
- The value of preoperative nerve conduction studies lies in obtaining the correct diagnosis and determining the severity of the median nerve disease, not in predicting postoperative outcome [6].
- Electrodiagnostic criteria used in some referenced studies were inadequate and not the most sensitive available, potentially leading to the erroneous conclusion that electrodiagnostic studies offer no additional diagnostic power in carpal tunnel syndrome [7].
- The value of electrodiagnostic testing is not negated by findings that it does not predict postoperative outcome [8].
- When signs and symptoms suggest mild-to-moderate median neuropathy and surgery is being considered, patients and clinicians might consider additional testing, such as electrodiagnostic studies or ultrasound, to increase the probability of actual median neuropathy that can benefit from surgery [9].
- Clinical, electrodiagnostic, and physical examination criteria need better definition to avoid inaccurate diagnoses and unnecessary surgeries [10].
- Highly sensitive tests are required to assess or exclude the diagnosis in one quarter of cases of carpal tunnel syndrome [11].
- Nerve conduction studies were more sensitive than sensibility testing in confirming the diagnosis of carpal tunnel syndrome [13].
- The combination of nerve conduction studies and sensibility testing is more sensitive than either test alone in confirming the diagnosis of carpal tunnel syndrome [13].
- Given specific clinical criteria for establishing the diagnosis of carpal tunnel syndrome, electrodiagnostic testing does not appear to correlate with improved final symptomatic outcome after carpal tunnel release [20].
- Surgical intervention is advocated for patients with symptoms only, even when electrodiagnostic studies are normal, in the context of cubital tunnel syndrome [21].
- The majority of neurosurgeons and orthopaedic surgeons seldom operate without electrodiagnostic confirmation in line with the Dutch consensus guideline on this subject [29].
- When used together, Semmes-Weinstein monofilament mappings and sensory nerve conduction parameters present a clearer picture of the patient's sensory status than either test used alone [31].
- Receiver operating characteristic curves showed distal sensory latency measurement to be a superior diagnostic test for carpal tunnel syndrome, with 3.3 ms as optimal upper limit of normal, giving a sensitivity of 74% and a specificity of 87% [45].
How It Works¶
Diagnostic Utility and Role¶
- The clinical, electrodiagnostic, and physical examination criteria need better definition to avoid inaccurate diagnoses and unnecessary surgeries [10].
- Electrodiagnostic studies are used as part of a clinical evaluation process and are considered a reasonable way to practice medicine [12].
Sensitivity and Specificity¶
- Nerve conduction studies were more sensitive than sensibility testing in confirming the diagnosis of carpal tunnel syndrome, but the combination of the two studies is more sensitive than either test alone [13].
- The sensitivity of the neurometer test alone was 69% and specificity was 100%, increasing to 84% sensitivity when combined with quantitative sensibility testing [28].
- The relative slowing of the antidromic sensory conduction velocity of the median nerve to the ring finger is determined easily and efficiently and imposes minimal strain on the patient [34].
Prognostic Value and Outcomes¶
- Compound muscle action potential amplitude, but not other conventional electrodiagnostic parameters, was predictive of functional outcomes after in situ decompression of the ulnar nerve [22].
- Suprascapular nerve dysfunction, evidenced by reduced nerve amplitudes and supraspinatus muscle atrophy, significantly predicts poor functional outcomes following shoulder hemiarthroplasty, even when tuberosities are well healed [19].
- This strength recovers gradually as the median nerve heals, but never returns to normal, indicating that this test can be extrapolated to the reinnervation of the abductor pollicies brevis [23].
Technical Considerations and Reporting¶
- There is variability with respect to the thoroughness of electrodiagnostic studies and in the quality of information in the reports [16].
- Electrodiagnostic reports should specifically indicate abnormalities of latency and conduction and present a clear description of the probable pathophysiologic processes rather than just compiling slight abnormalities [26].
- The conduction velocity of the ulnar nerve after an anterior transposition is determined by both the position of the elbow and the location for the measurement of the skin distance [37].
Physiological Mechanisms and Intraoperative Findings¶
- When in situ nerve strain reached 8.1 ± 0.5%, the compound muscle action potential was not evoked [33].
- Intraoperative conduction latencies indicated a dramatic and immediate reduction in the conduction latency across the carpal canal in all but seven patients, two of whom had diabetes [36].
- Electrodiagnostic studies revealed an acute median nerve lesion at the wrist with motor and/or sensory conduction blocks in 20/30 women with pregnancy-related carpal tunnel syndrome [18].
Comparative Modalities¶
- Ultrasound is a valid alternative confirmatory test compared with electrodiagnostic studies in detecting ulnar neuropathy at the elbow [14].
- The study confirms the high diagnostic value of the pre-operative antidromic sensory conduction velocity findings [25].
What the Evidence Shows¶
Diagnostic Role and Sensitivity¶
- The absence of any real difference in nerve conduction time between the working group with symptoms and the group with diagnosed carpal tunnel syndrome indicates a high probability that many participants with symptoms would have had abnormal findings on standard electrodiagnostic tests [5].
- There is a severe discordance between the estimated prevalence of mild-to-moderate carpal tunnel syndrome based on clinical signs and symptoms (73%) versus electrodiagnostic studies and ultrasound (51%) [27].
- The authors argue that the electrodiagnostic criteria used in the referenced study were inadequate and not the most sensitive available, potentially leading to the erroneous conclusion that electrodiagnostic studies offer no additional diagnostic power in carpal tunnel syndrome [7].
- Carpal tunnel injection is a reasonably accurate diagnostic test, as a good response to injection is an excellent diagnostic and prognostic sign for surgical treatment [42].
Prognostic Value and Outcomes¶
- Upper arm motor nerve conduction velocity might be a useful predictor of poor surgical outcome in cubital tunnel syndrome [32].
- Distal motor latency is a simple test with a predictive value of the postoperative neurophysiological and clinical outcome of carpal tunnel syndrome [39].
- The changes in electrophysiological findings occurring spontaneously in carpal tunnel syndrome and after treatment by injection are not statistically significant at two years [38].
Clinical Application and Reporting¶
- The author continues to use electrodiagnostic studies as part of a clinical evaluation process and considers this a reasonable way to practice medicine [12].
- The author proposes that the clinical, electrodiagnostic, and physical examination criteria need better definition to avoid inaccurate diagnoses and unnecessary surgeries [10].
- The study confirms the high diagnostic value of the pre-operative antidromic sensory conduction velocity findings in carpal tunnel syndrome [25].
- Surgical intervention is advocated for patients with symptoms only, even when electrodiagnostic studies are normal, in cases of cubital tunnel syndrome [21].
- The incidence of abnormal conduction times was not reliably correlated with either age or duration of paralysis in the paraplegic hand [24].
- In primates, there is no significant difference in the conduction velocity of peripheral nerves repaired in adults and those repaired in early life [15].
- Although there are essential differences between Semmes-Weinstein monofilament mappings and sensory nerve conduction parameters, when used together they present a clearer picture of the patient's sensory status than either test used alone [31].
- The strength of the abductor pollicis brevis recovers gradually as the median nerve heals but never returns to normal, indicating that this test can be extrapolated to the reinnervation of the abductor pollicis brevis [23].
- Chitosan phonophoresis demonstrated significant improvements in nerve conduction, pain reduction, and enhancement of hand function for mild to moderate cubital tunnel syndrome [17].
- All patients had good clinical and electrophysiological recovery at 6 months following single-stage opponensplasty added at the time of release for severe carpal tunnel syndrome [41].
- Three weeks after the operation, 77% of the patients in the tourniquet group had denervation in other than thenar muscles [46].
Practical Considerations¶
Diagnostic Interpretation and Utility¶
- Nerve conduction studies serve as a measure of impaired nerve function and the best available indicator of overall disease severity, rather than a test that determines the diagnosis [1].
- The value of preoperative nerve conduction studies lies in obtaining the correct diagnosis and determining the severity of median nerve disease, not in predicting postoperative outcome [6].
- Electrodiagnostic testing does not appear to correlate with improved final symptomatic outcome after carpal tunnel release given specific clinical criteria for establishing the diagnosis [20].
- When signs and symptoms suggest mild-to-moderate median neuropathy and surgery is being considered, patients and clinicians might consider additional testing, such as EDS or US, to increase the probability of actual median neuropathy that can benefit from surgery [9].
- The authors argue that the electrodiagnostic criteria used in the referenced study were inadequate and not the most sensitive available, potentially leading to the erroneous conclusion that electrodiagnostic studies offer no additional diagnostic power in CTS [7].
- This does not negate the value of electrodiagnostic testing [8].
Testing Variations and Screening¶
- Provocative nerve conduction testing is a useful and simple addition to the overall evaluation of patients with CTS, particularly those with otherwise normal findings on traditional electrodiagnostic studies [3].
- The absence of any real difference in nerve conduction time between the working group with symptoms and the group with diagnosed CTS indicates a high probability that many of the participants with symptoms would have had abnormal findings on standard electrodiagnostic tests [5].
- There is a significant discrepancy between the practice recommended by the Danish Society of Neurophysiology of performing neurophysiological investigations in all cases of suspected CTS and what is actually done in most surgical departments [35].
Specific Clinical Scenarios¶
- Upper arm motor nerve conduction velocity (MNCV) might be a useful predictor of poor surgical outcome in cubital tunnel syndrome [32].
- Surgical intervention is advocated for patients with symptoms only, even when electrodiagnostic studies are normal, in cases of electrodiagnostic-negative cubital tunnel syndrome [21].
- SSN dysfunction, evidenced by reduced nerve amplitudes and supraspinatus muscle atrophy, significantly predicts poor functional outcomes following shoulder hemiarthroplasty, even when tuberosities are well healed [19].
- The incidence of abnormal conduction times in the paraplegic hand was not reliably correlated with either age or duration of paralysis [24].
- Intraoperative electrodiagnosis may offer limited value in neonatal brachial plexus palsy surgery, but there is insufficient evidence to reach robust conclusions [44].
- This underscores the need for surgeons to carefully evaluate suprascapular nerve integrity in cases of rotator cuff tear [40].
Methodological and Prognostic Notes¶
- Only studies with randomization, blinding, and sham injection or sham surgery can address subjective symptoms and satisfaction reliably and accurately [30].
Key Evidence¶
- [L5] Nerve conduction studies should be understood not as a test that determines the diagnosis but as a measure of impaired nerve function, serving as the best available indicator of overall disease severity with some prognostic value for surgical outcome. [1] (10.1177/17531934231191685)
- [L3] We consider nerve conduction studies to be an indispensable part of the pre-operative evaluation. [2] (10.1016/0266-7681(94)90244-5)
- [L2] Provocative nerve conduction testing is a useful and simple addition to the overall evaluation of patients with CTS, particularly those with otherwise normal findings on traditional electrodiagnostic studies. [3] (10.1016/s0363-5023(97)80045-7)
- [L3] The selection of an appropriate electrical screening test for peripheral nerve injury, such as entrapment neuropathy, depends on the prevalence and seriousness of the target disease and the relative consequences of over- and underdiagnosis. [4] (10.1016/s0363-5023(96)80165-1)
- [L3] The absence of any real difference in nerve conduction time between the working group with symptoms and the group with diagnosed CTS indicates a high probability that many of the participants with symptoms would have had abnormal findings on standard electrodiagnostic tests. [5] (10.1016/0363-5023(92)90116-7)
- [L5] The value of preoperative nerve conduction studies lies in obtaining the correct diagnosis and determining the severity of the median nerve disease, not in predicting postoperative outcome. [6] (10.1016/s0363-5023(96)80384-4)
- [L5] The authors argue that the electrodiagnostic criteria used in the referenced study were inadequate and not the most sensitive available, potentially leading to the erroneous conclusion that electrodiagnostic studies offer no additional diagnostic power in CTS. [7] (10.1067/jhsu.2000.jjhsu00025a1le01)
- [L5] This does not negate the value of electrodiagnostic testing. [8] (10.1016/s0363-5023(96)80222-x)
- [L3] When signs and symptoms suggest mild-to-moderate median neuropathy and surgery is being considered, patients and clinicians might consider additional testing, such as EDS or US, to increase the probability of actual median neuropathy that can benefit from surgery. [9] (10.1097/corr.0000000000002751)
- [L5] The author proposes that the clinical, electrodiagnostic, and physical examination criteria need better definition to avoid inaccurate diagnoses and unnecessary surgeries. [10] (10.1016/s0363-5023(05)80209-6)
- [L3] Highly sensitive tests are required to assess or exclude the diagnosis in one quarter of cases of carpal tunnel syndrome. [11] (10.1016/0266-7681(94)90245-3)
- [L5] The author continues to use electrodiagnostic studies as part of a clinical evaluation process and considers this a reasonable way to practice medicine. [12] (10.1016/s0363-5023(96)80380-7)
- [L4] The results indicate that nerve conduction studies were more sensitive than sensibility testing in confirming the diagnosis of carpal tunnel syndrome, but the combination of the two studies is more sensitive than either test alone. [13] (10.1016/s0363-5023(82)80176-7)
- [L4] Ultrasound is a valid alternative confirmatory test compared with electrodiagnostic studies in detecting ulnar neuropathy at the elbow. [14] (10.1016/j.jhsa.2023.08.014)
- [L3] The study demonstrates that in primates there is no significant difference in the conduction velocity of peripheral nerves repaired in adults and those repaired in early life. [15] (10.1016/s0363-5023(83)80199-3)
- [L4] There is variability with respect to the thoroughness of electrodiagnostic studies and in the quality of information in the reports. [16] (10.1016/s0363-5023(98)80089-0)
- [L1] This approach demonstrated significant improvements in nerve conduction, pain reduction, and enhancement of hand function. [17] (10.1016/j.jht.2024.02.006)
- [L4] Electrodiagnostic studies revealed an acute median nerve lesion at the wrist with motor and/or sensory conduction blocks in 20/30 women. [18] (10.1016/s0266-7681(98)80232-5)
- [L3] SSN dysfunction, evidenced by reduced nerve amplitudes and supraspinatus muscle atrophy, significantly predicts poor functional outcomes following SHA, even when tuberosities are well healed. [19] (10.1016/j.jse.2025.07.001)
- [L3] Given specific clinical criteria for establishing the diagnosis of carpal tunnel syndrome, electrodiagnostic testing does not appear to correlate with improved final symptomatic outcome after carpal tunnel release. [20] (10.1016/s0363-5023(96)80164-x)
- [L2] We advocate surgical intervention for patients with symptoms only, even when electrodiagnostic studies are normal. [21] (10.1053/jhsu.2001.26327)
- [L2] Compound muscle action potential amplitude, but not other conventional electrodiagnostic parameters, was predictive of functional outcomes after in situ decompression of the ulnar nerve. [22] (10.1016/j.jhsa.2022.10.008)
- [L5] This strength recovers gradually as the median nerve heals, but never returns to normal, indicating that this test can be extrapolated to the reinnervation of the abductor pollicies brevis. [23] (10.1016/s0266-7681(03)00022-6)
- [L4] The incidence of abnormal conduction times was not reliably correlated with either age or duration of paralysis. [24] (10.1016/s0363-5023(88)80132-1)
- [L4] The study confirms the high diagnostic value of the pre-operative antidromic sensory conduction velocity findings. [25] (10.1016/0266-7681(88)90161-1)
- [L5] EDX reports should specifically indicate abnormalities of latency and conduction and present a clear description of the probable pathophysiologic processes rather than just compiling slight abnormalities. [26] (10.1016/s0363-5023(96)80298-x)
- [L5] There is a severe discordance between the estimated prevalence of mild-to-moderate carpal tunnel syndrome based on clinical signs and symptoms (73%) versus electrodiagnostic studies and ultrasound (51%), calling into question whether clinicians can confidently diagnose patients with mild-to-moderate CTS. [27] (10.1097/corr.0000000000002822)
- [L3] The sensitivity of the neurometer test alone was 69% and specificity was 100%, increasing to 84% sensitivity when combined with quantitative sensibility testing. [28] (10.1016/0363-5023(92)90117-8)
- [L4] The majority of neurosurgeons and orthopaedic surgeons seldom operate without electrodiagnostic confirmation in line with the Dutch consensus guideline on this subject. [29] (10.1016/j.jhse.2007.09.007)
- [L4] Although there are essential differences in these two tests, when used together they present a clearer picture of the patient's sensory status than either test used alone. [31] (10.1016/s0894-1130(87)80010-8)
- [L3] Upper arm motor nerve conduction velocity (MNCV) might be a useful predictor of poor surgical outcome. [32] (10.1177/17585732241293360)
- [Paper] The results showed that when the in situ nerve strain reached 8.1 ± 0.5%, the compound muscle action potential was not evoked. [33] (10.1016/s0736-0266(02)00080-3)
- [L3] The relative slowing of the antidromic sensory conduction velocity of the median nerve to the ring finger is determined easily and efficiently and imposes minimal strain on the patient. [34] (10.1016/j.jhsa.2004.04.026)
- [L4] There is a significant discrepancy between the practice recommended by the Danish Society of Neurophysiology of performing neurophysiological investigations (NI) in all cases of suspected CTS and what is actually done in most surgical departments. [35] (10.1016/s0266-7681(97)80443-3)
- [L4] The results of intraoperative conduction latencies indicated a dramatic and immediate reduction in the conduction latency across the carpal canal in all but seven patients, two of whom had diabetes. [36] (10.1016/s0363-5023(78)80119-1)
- [L4] The conduction velocity of the ulnar nerve after an anterior transposition is determined by both the position of the elbow and the location for the measurement of the skin distance. [37] (10.1016/s0363-5023(87)80051-5)
- [L3] The changes in electrophysiological findings occurring spontaneously in carpal tunnel syndrome and after treatment by injection are not statistically significant at two years. [38] (10.1016/0266-7681(92)90191-4)
- [L3] DML is a simple test with a predictive value of the postoperative neurophysiological and clinical outcome of carpal tunnel syndrome. [39] (10.1016/s0266-7681(97)80355-5)
- [L5] This underscores the need for surgeons to carefully evaluate suprascapular nerve integrity in such cases. [40] (10.1186/s12891-025-09195-6)
- [L3] All patients had good clinical and electrophysiological recovery at 6 months. [41] (10.1177/1558944716660555fx)
- [L4] Results suggest that carpal tunnel injection is also a reasonably accurate diagnostic test, as a good response to injection is an excellent diagnostic and prognostic sign for surgical treatment. [42] (10.1016/s0363-5023(84)80065-9)
- [L4] Intraoperative electrodiagnosis may offer limited value in neonatal brachial plexus palsy surgery, but there is insufficient evidence to reach robust conclusions. [44] (10.1177/17531934261478357)
- [L3] Receiver operating characteristic curves showed distal sensory latency measurement to be a superior diagnostic test, with 3.3 ms as optimal upper limit of normal, giving a sensitivity of 74% and a specificity of 87%. [45] (10.1016/s0363-5023(96)80020-7)
- [L1] Three weeks after the operation 77% of the patients in the tourniquet group had denervation in other than thenar muscles. [46] (10.1016/s0363-5023(89)80011-5)
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