Sensibilidad y especificidad de tres métodos complementarios para el diagnóstico de síndrome de túnel carpiano / Sensitivity and specificity of three complementary methods in the diagnosis of carpal tunnel syndrome

Resumen: Introducción: Actualmente, no existe un estándar de referencia aceptado universalmente para el diagnóstico del síndrome de túnel carpiano, por lo que se le considera una patología de «clase latente¼, es decir, que carece de alguna prueba diagnóstica que dé certeza absoluta de la presencia de la enfermedad. Métodos: Estudio prospectivo, observacional y analítico en el cual se evaluaron los tres métodos diagnósticos utilizados para el síndrome de túnel carpiano (examen clínico, ecografía y electromiografía). En él, se establecieron valores de normalidad para cada método diagnóstico. Resultados: Se evaluó un total de 50 personas (14 hombres y 36 mujeres). El examen clínico presentó correlación positiva y significativa con el diámetro del nervio mediano afectado (ecografía) (R = 0.694 y p = 0.032). Los valores del área bajo la curva (AUC, por sus siglas en inglés) para la velocidad de conducción del nervio mediano (VCNM), velocidad de conducción de nervio cubital (VCNC) y latencia distal motora (LDM) por electromiografía fueron de 0.60, 0.519 y < 0.50, respectivamente, lo cual determinó que el valor diagnóstico de las características por electromiografía es malo. Conclusión: Nuestro trabajo establece al examen clínico como una herramienta de buena calidad, siendo el método más sensible para el diagnóstico de síndrome de túnel carpiano. Si existiera la necesidad de realizar una confirmación diagnóstica, la ecografía mostró ser un estudio altamente satisfactorio, el cual genera menos estrés, dolor e invasión al paciente, disminuyendo, a su vez, el gasto de salud y agilizando el proceso.

Abstract: Introduction: Currently there is no universally accepted standard of reference for the diagnosis of carpal tunnel syndrome so it is considered a «latent class¼ pathology, that is, it lacks any diagnostic tests that absolutely certain the presence of disease. Methods: Prospective, observational and analytical study evaluating the three diagnostic methods used for carpal tunnel syndrome (clinical examination, ultrasound and electromyography). Normality values were set for each diagnostic method. Results: 50 people (14 men and 36 women) were evaluated. The clinical examination showed a positive and significant correlation with the diameter of the affected median nerve (ecography) (R = 0.694, p = 0.032). The values of the under the curve area (UCA) for median nerve conduction speed (MNCS), cubital nerve conduction speed (CNCS), and distal latency (DL) by electromyography were 0.60, 0.519 and less than 0.50 respectively. This states that the diagnostic value of electromyography characteristics is bad. Conclusion: Our work establishes clinical examination as a good quality tool being the most sensitive method for diagnosing carpal tunnel syndrome. If there was a need for diagnostic confirmation, the ultrasound proved to be a highly satisfactory study generating less stress, pain and invasion to the patient, decreasing health expenditure and speeding up the process.

Potencial de ação duplo e alterações ecográficas do nervo mediano em doentes com síndrome do túnel cárpico / Double peak action potential and ultrasonography nerve evaluation in patients with carpal tunnel syndrome

Introdução: A síndrome do túnel cárpico (STC) é sustentada pela presença de lentificação do potencial de ação do nervo mediano no estudo ortodrómico de condução nervosa sensitiva em comparação com o nervo radial (EC-MR). Uma técnica modificada de registo simultâneo de ambos os nervos (EC-MRsimul) pode ser utilizada, detetando a lentificação do nervo mediano através da presença de potencial de ação sensitivo duplo (PAS-D). O objetivo deste estudo é correlacionar o PAS-D com os achados de EC-MR e com o edema perineural em doentes com diagnóstico de STC. Métodos: Indivíduos saudáveis e doentes com STC há menos de 12 meses foram submetidos a avaliação eletrofisiológica, incluindo o EC-MR e o EC-MRsimul. Foi também realizada ultrassonografia para registo da área seccional do nervo mediano (AS-NM) no punho e antebraço e, respetivo índice punho-antebraço (I-PA). Resultados: Foram recrutados 38 doentes com idade média de 54,8 ± 15,3 anos com STC e 18 indivíduos saudáveis. A diferença de latência distal entre o nervo mediano e radial foi superior nos doentes (0,80 ± 0,30ms vs. 0,15 ± 0,20ms; p=0,015). O EC­MRsimul demonstrou a presença de PAS-D nos indivíduos sintomáticos. A AS­NM no punho foi também superior nos doentes (8,9 ± 0,9mm2 vs. 6,6 ± 0,7mm2; p<0.003), tendo sido identificado um quisto sinovial e um neurinoma. O edema perineural traduzido pela AS-SM correlacionou-se positivamente com a diferença de latência interpico no EC-MR e com a presença de PAS-D. Conclusão: O PAS-D está associado à presença de lentificação da condução e ao edema perineural do nervo mediano no contexto de STC ou devido a lesões ocupantes de espaço. (AU)

Introduction: Carpal tunnel syndrome (CTS) is characterized by median nerve action potential slowing, which can be shown in comparative orthodromic sensory nerve conduction studies between median and radial nerve (NCS-MR). A modified technique with simultaneous recording of both nerves (NCS-MRsimul) can also be used to detect median nerve slowing through the presence of double peak action potential (DPp). The study aims to correlate the presence of DPp with NCS-MR findings and with perineural edema in patients diagnosed with STC. Methods: Healthy individuals and patients with CTS for less than 12 months underwent NCS-MR and MRsimul. An ultrasonography evaluation was also performed to record the medial nerve sectional area (SA-MN) on the wrist and forearm, and the wrist-to-forearm ratio (WFR) was calculated. Results: We recruited 38 patients with CTS whose mean age was 54.8 ± 15.3 years and 18 healthy individuals. Distal latency difference between the median and radial nerves was higher in patients with CTS (0.80 ± 0.30 ms vs. 0.15 ± 0.20 ms, p = 0.015). NCS-MRsimul showed DPp in symptomatic individuals. SA-MN in the wrist was also higher in patients with CTS (8.9 ± 0.9 mm2 vs. 6.6 ± 0.7 mm2 , p <0.003). Ultrasonography evaluation identified a synovial cyst and a neurinoma. Perineural edema traduced by higher SA-MN and WFR correlated positively with interpeak latency difference in NCS-MR and with the presence of DPp. Conclusions: DPp was associated with median nerve sensory action potential slowing and with perineural edema due to either CTS or to space-occupying lesions. (AU)

Cambios morfológicos y dimensionales en el túnel del carpo por resonancia magnética (preoperatorios y postoperatorios) / Morphological and dimensional changes of the magnetic resonance imaging in the carpal tunnel (pre- and postoperatively)

Resumen: Introducción: El síndrome del túnel de carpo es la neuropatía por compresión más frecuente de la extremidad superior y la liberación del nervio mediano es el tratamiento quirúrgico que se aplica. Existen diversas técnicas quirúrgicas que se utilizan para tratar este padecimiento; sin embargo, esa cavidad virtual a la que llamamos túnel del carpo sufre diversos cambios morfológicos y dimensionales previo y posterior a la cirugía con el uso de diversas técnicas que el cirujano elige. Material y métodos: Estudio observacional, prospectivo y longitudinal realizado en el período comprendido de Marzo a Noviembre de 2009. Se estudiaron pacientes de ambos sexos con diagnóstico de síndrome del túnel del carpo, a los cuales se les realizaron estudios de resonancia magnética antes y después de la cirugía para obtener mediciones y análisis. Resultados: Se evaluaron 25 pacientes con una media de 40 años, 14 pacientes femeninos y 11 masculinos, encontrándose un desplazamiento palmar del nervio posterior a la cirugía con un diámetro de 6.2 mm manteniendo cambios de la forma oval a una circular. Discusión: Existen cambios morfológicos y dimensionales evaluados por resonancia magnética después de la liberación, por lo cual se relaciona la respuesta clínica favorable posterior a la cirugía; sin embargo, encontramos un diámetro mayor del nervio, esto debido a que se les realizó neurólisis.

Abstract: Introduction: Carpal tunnel syndrome is the most common compression neuropathy of the upper limb, and the release of the median nerve is the surgical treatment that is carried out. There are several surgical techniques used to treat this condition; However, this virtual cavity, which we call the carpal tunnel, undergoes several morphological and dimensional changes, prior to surgery and after surgery using the various techniques that the surgeon has a predilection for. Material and methods: Observational, prospective and longitudinal study conducted in the period from March to November 2009. We studied patients of both sex, with a diagnosis of carpal tunnel syndrome, who underwent MRI pre and post-surgery studies, to which measurements and analysis of it were made. Results: We evaluated 25 patients with an average of 40 years, 14 female patients and 11 male, finding a palmar displacement of the nerve after surgery with a diameter of 6.2 mm, maintaining changes from the oval to a circular shape. Discussion: There are morphological and dimensional changes, evaluated by magnetic resonance after the release, for which the favorable clinical response after surgery is related; however, we found a larger diameter of the nerve due to the fact that they underwent neurolysis.

Variantes anatómicas del canal carpiano y distancias de estructuras vasculares en ecografía / Anatomical variants the carpal tunnel and distances of vascular structures in ultrasound

El síndrome de canal carpiano es una patología frecuente. Si bien el diagnóstico es clínico, la ecografía cumple un rol en caso de duda diagnóstica y como apoyo a proce-dimientos intervencionales.Existen variables anatómicas y distancias de estructuras vasculares útiles de conocer antes de planear un gesto quirúrgico o de infiltración para disminuir el riesgo de lesiones secundarias, en donde la ecografía podría tener un rol.Estudiamos una muestra de 267 ecografías de muñeca con especial hincapié en va-riantes neurogénicas, vasculares o tendinosas que podrían resultar lesionadas en relación a algún procedimiento.

Carpal tunnel syndrome is a frequent pathology. Although the diagnosis is clinical, ultrasound plays a role in case of diagnostic doubt and as support and guide for inter-ventional procedures.There are anatomical variants and distances of vascular structures that may be useful to know before planning a surgical or infiltration procedure to reduce the risk of iat-rogenic injuries, where ultrasound could play a role.We studied a sample of 267 wrists ultrasounds with special emphasis on neurogenic, vascular or tendinous variants that could be injured in relation to procedures.

Sonographic Findings of the Bifid Median Nerve and Persistent Median Artery in Carpal Tunnel: A Preliminary Study in Chinese Individuals

OBJECTIVE: The aim of this study was to investigate the prevalence of anatomic variations of the bifid median nerve, persistent median artery and persistent median vein in Chinese individuals and their relationship with carpal tunnel syndrome. METHODS: One hundred and sixty median nerves were examined using ultrasonography and colour Doppler ultrasonography. The location, shape, and size of the bifid median nerve, persistent median artery and persistent median vein were recorded. The cross-sectional area of the bifid median nerve (two trunks) was measured at the level of the pisiform. RESULTS: Among the 160 wrists examined, a bifid median nerve was observed in 15 (9.4%) wrists, and a persistent median artery was observed in 12 (7.5%) wrists. These two variations either coexisted or were observed independently, and the probability of coexistence (6.3%) was higher than the probability of existing independently (bifid median nerve only 3.1%, persistent median artery only 1.3%). The cross-sectional area of the radial trunk was greater than (13 in 15, 86.7%) the cross-sectional area of the ulnaris trunk. Persistent median vein was observed in 9 wrists (5.6%). CONCLUSIONS: The persistent median artery and bifid median nerve tend to coexist, and the persistent median vein sometimes runs parallel to the persistent median artery. Their positional relationship in carpal tunnel is uncertain, and thus, preoperative ultrasound is necessary. These three variations do not present any additional risk for the development of carpal tunnel syndrome.

Changes in Clinical Symptoms, Functions, and the Median Nerve Cross-Sectional Area at the Carpal Tunnel Inlet after Open Carpal Tunnel Release

BACKGROUND: The aim of this study was to investigate the relationship between clinical symptoms and cross-sectional area (CSA) of the median nerve at the carpal tunnel inlet before and after open carpal tunnel release (CTR). METHODS: Thirty-two patients (53 hands) that underwent open CTR for idiopathic carpal tunnel syndrome were prospectively enrolled. Median nerve CSA at the carpal tunnel inlet was measured preoperatively and at 2 and 12 weeks after CTR by high resolution ultrasonography. The Boston carpal tunnel questionnaire (BCTQ) was also completed at these times. RESULTS: BCTQ symptom (BCTQ-S) score was significantly improved at 2 weeks postoperatively, but BCTQ function (BCTQ-F) score and CSA were significantly improved at 12 weeks postoperatively. Preoperative CSA was significantly correlated with preoperative BCTQ-S and BCTQ-F scores but was not significantly correlated with postoperative BCTQ scores or postoperative changes in BCTQ scores. Postoperative median nerve CSA was not significantly correlated with postoperative BCTQ-S or BCTQ-F scores, and postoperative changes in median nerve CSA were not significantly correlated with postoperative changes in BCTQ-S or BCTQ-F scores. CONCLUSIONS: The study shows clinical symptoms resolve rapidly after open CTR, but median nerve swelling and clinical function take several months to recover. In addition, preoperative median nerve swelling might predict preoperative severities of clinical symptoms and functional disabilities. However, postoperative reductions in median nerve swelling were not found to reflect postoperative reductions in clinical symptoms or functional disabilities.

Schwannoma como etiologia de síndrome do túnel do carpo ­ relato de caso / Schwannoma as a Cause of Carpal Tunnel Syndrome ­ a Case Report

A síndrome do túnel do carpo (STC) é uma condição clínica resultante da compressão do nervo mediano no túnel do carpo. É a neuropatia de maior incidência no membro superior e apresenta diferentes etiologias, entre elas o distúrbio osteomuscular relacionado ao trabalho (DORT) e, mais raramente, a tumores de nervo periférico. O DORT é a etiologiamais comum da STC e vemaumentando sua incidência por causa de sua associação com o trabalho. Eentre os tumores que envolvem o nervo mediano está o schwannoma, ou neurilemoma, que também é o tumor benigno mais comum de nervos periféricos. Este relato almeja descrever um caso de schwannoma como etiologia da STC.

The carpal tunnel syndrome (CTS) is a clinical condition resulting from compression of the median nerve in the carpal tunnel. It is the neuropathy of higher incidence in the upper limb and as different etiologies, is related to work-related musculoskeletal disorders (WMSDs) and rarely tumors of peripheral nerve. The WMSDs are the most common, and its incidence is increasing more andmore due to the intimate association with type of work. Among the tumors involving median nerve is the Schwannoma, or neurilemoma. The Schwannoma is the most common benign tumor of the peripheral nerve. This report aims to describe a case of schwannoma as a cause of CTS.

Ultrassonografia no diagnóstico da síndrome do túnel do carpo / Ultrasonography as a tool in diagnosis of carpal tunnel syndrome

RESUMOObjetivoDeterminar a importância da ultrassonografia (US) no diagnóstico da síndrome do túnel do carpo (STC).MétodosDuzentos pacientes (400 mãos) foram submetidos a uma US do punho para medir a área do nervo mediano (ANM). Foram perguntados quanto à presença de parestesia e dor no território do nervo mediano e submetidos aos testes de Tinel e Phalen. Uma ANM > 9 mm2 foi considerada diagnóstica de STC.ResultadosO valor da ANM medida pela US foi > 9 mm2 em 27% das mãos. Foram encontrados uma boa associação com a dor (p < 0,0001), parestesia (p < 0,0001), teste de Tinel (p < 0,0001) e teste de Phalen (p < 0,0001). De acordo com os critérios clínicos para a classificação da STC da American Academy of Neurology, a ANM medida pela US teve 64,8% de sensibilidade e 77% de especificidade nessa amostra.ConclusãoA mensuração da ANM pela US é adequada e pode ser usada como primeira opção para a investigação de pacientes com STC.

ABSTRACTObjectiveWe aimed to determine the value of ultrasonography (US) in the diagnosis of carpal tunnel syndrome (CTS).MethodsTwo hundred patients (400 hands) were submitted to wrist US to measure median nerve area (MNA), questioning on paresthesia and pain in the median nerve territory, Tinel and Phalen maneuvers. An MNA >9 mm2 was considered diagnostic of CTS.ResultsMeasurement of MNA by US was >9 mm2 in 27% of the hands. A good association with pain (p < 0.0001), paresthesia (p < 0.0001), Tinel test (p < 0.0001) and Phalen test (p < 0.0001) was found. According to the clinical criteria for classification of CTS from American Academy of Neurology the MNA by US had 64.8% of sensibility and 77.0% of specificity in this sample.ConclusionMeasurement of MNA by US performs well and can be used as first option for the investigation of patients with CTS.

Ultrasound evaluation on carpal tunnel syndrome before and after bariatric surgery / Avaliação ultrassonográfica da síndrome do túnel do carpo antes e após cirurgia bariátrica

Objective: To evaluate the prevalence of carpal tunnel syndrome in candidates for bariatric surgery comparing with the non-obese population and verify the effects on it of bariatric treatment. Methods: We studied three groups of individuals: 1) patients waiting for bariatric surgery (preoperative); 2) individuals who had already undergone the procedure (postoperative); and 3) control group. We collected demographic and clinical data of carpal tunnel syndrome. The Ultrasound examination was carried out to diagnose the syndrome by measuring the median nerve area. Results: We included 329 individuals (114 in the preoperative group, 90 in the postoperative group and 125 controls). There was a higher prevalence of paresthesias (p=0.0003), clinical tests (p=0.0083) on the preoperative group when compared with controls (p<0.00001). There were lowe levels of paresthesias (p=0.0002) and median nerve area (p=0.04) in postoperative patients but with no significant difference in general. A significant difference was found between the preoperative and postoperative groups (p=0.05) in those who performed non-manual work. Conclusion: There was a higher prevalence of carpal tunnel syndrome in the preoperative group compared with the control one, but no significant difference was observed between the pre and postoperative groups in general. There was difference between pre and postoperative groups for non-manual workers. .

Objetivo: verificar a prevalência da STC em pacientes obesos candidatos à cirurgia bariátrica comparada com a prevalência em indivíduos não obesos e em pacientes já submetidos ao procedimento cirúrgico para verificar se as medidas de perda de peso influem na prevalência e gravidade dos sintomas. Métodos: três grupos de indivíduos foram estudados: 1) candidatos à cirurgia bariátrica (pré-operatório); 2) já submetidos ao tratamento cirúrgico bariátrico (pós-operatório) e 3) grupo controle. Foram coletados dados demográficos e clínicos referentes à síndrome do túnel do carpo. Foi realizada ultrassonografia para medição da área da secção transversa do nervo mediano para o diagnóstico da síndrome. Resultados: foram incluídos 329 indivíduos (114 no grupo pré-operatório, 90 no grupo pós-operatório e 125 controles). Houve maior prevalência de parestesias quando se comparou o grupo pré-operatório com o controle (p<0,00001). Houve diminuição das parestesias (p=0,0002) e da área da secção transversa do nervo mediano (p=0.04) nos pacientes do pós-operatório, mas não houve diferença significativa na prevalência geral da síndrome do túnel do carpo. Foi observada diferença significativa entre os grupos pré e pós-operatório (p=0,05) nos indivíduos que realizavam trabalho não manual. Conclusão: houve maior prevalência da síndrome do túnel do carpo entre o grupo pré-operatório comparado com o controle, mas não se observou diferença significativa entre os grupos pré e pós-operatório no geral. Houve diferença entre os grupos pré e pós-operatório dentre os trabalhadores não manuais. .

RE: Value of Power Doppler and Gray-Scale US in the Diagnosis of Carpal Tunnel Syndrome: Contribution of Cross-Sectional Area just before the Tunnel Inlet as Compared with the Cross-Sectional Area at the Tunnel

No abstract available.

Value of Power Doppler and Gray-Scale US in the Diagnosis of Carpal Tunnel Syndrome: Contribution of Cross-Sectional Area just before the Tunnel Inlet as Compared with the Cross-Sectional Area at the Tunnel

OBJECTIVE: To determine the value of gray-scale and power Doppler ultrasonography in the evaluation of carpal tunnel syndrome (CTS). MATERIALS AND METHODS: Median nerves at the carpal tunnel were evaluated by using gray-scale and power Doppler ultrasonography and by using accepted and new criteria in 42 patients with CTS (62 wrists) confirmed by electromyogram and 33 control subjects. We evaluated the cross-sectional area of the nerve just proximal to the tunnel inlet (CSAa), and at mid level (CSAb). We then calculated the percentage area increase of CSAb, and area difference (CSAb-CSAa). We measured two dimensions of the nerve at the distal level to calculate the flattening ratio. The power Doppler ultrasonography was used to assess the number of vessels, which proceeded to give a score according to the vessel number, and lastly evaluated the statistical significance by comparing the means of patients with control subjects by the Student t test for independent samples. Sensitivities and specificities were determined for sonographic characteristics mentioned above. We obtained the receiver operating characteristic (ROC) curve to assess the optimal cut-off values for the diagnosis of CTS. RESULTS: A statistically significant difference was found between patients and the control group for mean CSAb, area difference, percentage area increase, and flattening ratio (p < 0.001, p < 0.001, p < 0.001, p < 0.05, respectively). From the ROC curve we obtained optimal cut-off values of 11 mm2 for CSAb, 3.65 for area difference, 50% for the percentage of area increase, and 2.6 for the flattening ratio. The mean number of vessels obtained by power Doppler ultrasonography from the median nerve was 1.2. We could not detect vessels from healthy volunteers. Mean CSAbs related to vascularity intensity scores were as follows: score 0: 12.3 +/- 2.8 mm2, score 1: 12.3 +/- 3.1 mm2, score 2: 14.95 +/- 3.5 mm2, score 3: 19.3 +/- 3.8 mm2. The mean PI value in vessels of the median nerve was 4.1 +/- 1. CONCLUSION: Gray-scale and power Doppler ultrasonography are useful in the evaluation of CTS.