Upper limb nerve variations may alter clinical diagnosis: a scoping review / Las variaciones nerviosas del miembros superior pueden alterar el diagnóstico clínico: una revisión de alcance

SUMMARY: Upper limb nerve variations may be related to the absence of a nerve, an interconnection between two nerves or a variant course. The purpose of this review is to screen the existing literature on upper limb nerve variations that may alter the neurologic diagnostic process. A scoping review was performed following PRISMA for Scoping Reviews guidelines. Initially, 1331 articles were identified by searching Pubmed and Web of Science until the 22nd of October 2022. After screening, reading, and additional searching 50 articles were included in this review. Variations were divided into two categories: 1) variations causing a different innervation pattern involving sensory, motor, or both types of fibers, and 2) variations causing or related to compression syndromes. Two-thirds of the included articles were cadaver studies. Nine articles were diagnostic studies on symptomatic or healthy individuals involving medical imaging and/or surgery. Nerve variations that may cause a different innervation pattern concern most frequently their interconnection. The connection between the median and musculocutaneous nerve in the upper limb and the connection between the median and ulnar nerve in the forearm (Martin-Gruber) or hand (Riche-Cannieu) may be present in half of the population. Injury to these connections may cause compound peripheral neuropathies a result of variant sensory and motor branching patterns. Muscular, vascular, or combined anomalies in the forearm were reported as causes of entrapment neuropathies. These nerve variations may mimic classical entrapment syndromes such as carpal tunnel syndrome or compression at ulnar canal (Guyon's canal). Knowledge of frequent nerve variations in the arm may be important during the diagnostic process and examination. Variant innervation patterns may explain non-classical clinical signs and/or symptoms during provocative tests. Classical nerve compression syndromes in the arm may warrant for differential diagnosis, especially in the case of persistent or recurrent symptoms.

Las variaciones nerviosas del miembro superior pueden estar relacionadas con la ausencia de un nervio, una interconexión entre dos nervios o un curso variante. El objetivo de esta revisión fue examinar la literatura existente sobre las variaciones de los nervios de los miembros superiores que pueden alterar el proceso de diagnóstico neurológico. Se realizó una revisión de alcance siguiendo las pautas de PRISMA para revisiones de alcance. Inicialmente, se identificaron 1331 artículos mediante la búsqueda en Pubmed y Web of Science hasta el 22 de octubre de 2022. Después de la selección, la lectura y la búsqueda adicional, se incluyeron 50 artículos en esta revisión. Las variaciones se dividieron en dos categorías: 1) variaciones que causan un patrón de inervación diferente que involucra fibras sensoriales, motoras o de ambos tipos, y 2) variaciones que causan o están relacionadas con síndromes de compresión. Dos tercios de los artículos incluidos eran estudios de cadáveres. Nueve artículos fueron estudios de diagnóstico en individuos sintomáticos o sanos que involucraron imágenes médicas y/o cirugía. Las variaciones nerviosas que pueden causar un patrón de inervación diferente se refieren con mayor frecuencia a su interconexión. La conexión entre el nervio mediano y musculocutáneo en el miembro superior y la conexión entre el nervio mediano y ulnar en el antebrazo (Martin-Gruber) o la mano (Riche-Cannieu) puede estar presente en la mitad de la población. La lesión de estas conexiones puede causar neuropatías periféricas compuestas como resultado de patrones de ramificación variantes sensitivos y motores. Se informaron anomalías musculares, vasculares o combinadas en el antebrazo como causas de neuropatías por atrapamiento. Estas variaciones nerviosas pueden imitar los síndromes de atrapamiento clásicos, como el síndrome del túnel carpiano o la compresión en el canal ulnar. El conocimiento de las variaciones nerviosas frecuentes en el brazo puede ser importante durante el proceso de diagnóstico y examen. Los patrones de inervación variantes pueden explicar los signos y/o síntomas clínicos no clásicos durante las pruebas de provocación. Los síndromes clásicos de compresión nerviosa en el brazo pueden justificar el diagnóstico diferencial, especialmente en el caso de síntomas persistentes o recurrentes.

Nervio interóseo posterior: origen, localización y trayecto nervioso: una revisión / Posterior interosseous nerve: origin, location and nerve path: a review

RESUMEN: El nervio interóseo posterior (NIP) ha sido utilizado como sinónimo ocontinuación inmediata del ramo profundo del nervio radial (RPNR) al emerger en el compartimiento posterior del antebrazo. Su origen tampoco es claro, describiéndose como nervio interóseo posterior a su trayecto proximal, intermedio o distal al músculo supinador. El objetivo de esta revisión es detallar la visión de diversos autores respecto al origen y trayecto del NIP, proponiendo una correcta terminología para estas estructuras. Se realizó una revisión bibliográfica de varios textos y de algunos artículos utilizados para la enseñanza de la anatomía humana, publicados entre los años 1800 y la actualidad. En la búsqueda, se determinaron criterios de inclusión que consideraban, anatomía humana, escritos en español, francés o inglés y que aludieran al NIP. Tras la exploración inicial se localizaron 18 libros, procedentes de Francia, Rusia, España, Argentina, Estados Unidos, Canadá, Reino Unido, Alemania, India y México. Una descripción del NIP más precisa, en cuanto al origen, trayecto y función, es aquella postulada por la vertiente francesa, correspondiendo a un origen terminal del ramo profundo del nervio radial, luego de emitir sus ramos musculares. Este delgado nervio transcurre adosado a la membrana interósea para luego avanzar por el cuarto compartimiento extensor, distribuyéndose en las articulaciones dorsales del carpo a quienes inerva sensitiva y propioceptivamente.

SUMMARY: The posterior interosseous nerve (PIN) has been used as a synonym or immediate continuation of the deep branch of the radial nerve as it emerges in the posterior compartment of the forearm. Its origin is not clear either, being described as a posterior interosseous nerve to its proximal, intermediate or distal path to the supinator muscle. The objective of this review is to detail the vision of various authors regarding the origin and path of the PIN, proposing a correct terminology for these structures. A bibliographic review of several texts and some articles used for the teaching of human anatomy, published between the 1800s and the present day, was carried out. In the search, inclusion criteria were determined that considered human anatomy, written in Spanish, French or English and that alluded to the PIN. After the initial exploration, 18 books were located, coming from France, Russia, Spain, Argentina, the United States, Canada, the United Kingdom, Germany, India and Mexico. A more precise description of the PIN, in terms of origin, path and function, is that postulated by the French literature, corresponding to a terminal origin of the deep branch of the radial nerve, after emitting its muscular branches. This thin nerve runs attached to the interosseous membrane to then advance through the fourth extensor compartment, distributing itself in the dorsal carpal joints to which it innervates sensitively and proprioceptively.

Accuracy of sonographic identification of suprascapular nerve at supraclavicular fossa: a cadaveric study / Precisión de la identificación ecográfica del nervio supraescapular en la fosa supraclavicular: un estudio cadavérico

SUMMARY: Sonographic identification of suprascapular nerve (SSN) is essential for diagnosis of suprascapular neuropathy and ultrasound-guided suprascapular nerve block. This study aims to demonstrate the accuracy of identification of SSN at supraclavicular region by ultrasonography in fresh cadavers. Ninety-three posterior cervical triangles were examined. With ultrasonography, SSN emerging from the upper trunk of brachial plexus was identified and followed until it passed underneath the inferior belly of omohyoid muscle. Sonographic visualization of SSN in supraclavicular fossa was recorded. Then, cadaveric dissection was performed to determine the presence or absence of SSN. An agreement between sonographic identification and direct visualization was specified and categorized the following three patterns: "correctly identified" (pattern I), "incorrectly identified" (pattern II), and "unidentified" (pattern III). The identification of SSN using sonography was correct in almost 90 %. The diameter of SSN with pattern I was the largest compared to those of other two patterns. In pattern I, SSN ran laterally from the upper trunk of brachial plexus and passed underneath the inferior belly of omohyoid muscle. Therefore, SSN was easily identified under ultrasonography. In pattern II, nerve identified by ultrasonography was literally the dorsal scapular nerve. In pattern III, SSN was unable to be identified because of its anatomical variation. The accuracy of ultrasonographic identification of SSN at supraclavicular fossa is high and the key sonoanatomical landmarks are the lateral margin of brachial plexus and the inferior belly of omohyoid muscle. The anatomical variants of SSN are reasons of incorrect or unable identification of SSN under ultrasonography.

RESUMEN: La identificación ecográfica del nervio supraescapular (NSE) es esencial para el diagnóstico de neuropatía supraescapular y bloqueo del nervio supraescapular mediante la ecografía. Este estudio tiene como objetivo demostrar la precisión de la identificación de NSE en la región supraclavicular por ecografía en cadáveres frescos. Se examinaron noventa y tres triángulos cervicales posteriores. Se identificó el NSE emergente de la parte superior del tronco del plexo braquial con la ecografía, y se siguió hasta su trayecto por debajo del vientre inferior del músculo omohioideo. Se registró la visualización ecográfica del NSE en la fosa supraclavicular. Luego, se realizó disección cadavérica para determinar la presencia o ausencia de NSE. Se especificó un acuerdo entre la identificación ecográfica y la visualización directa y se categorizaron los siguientes tres patrones: "identificado correctamente" (patrón I), "identificado incorrectamente" (patrón II) y "no identificado" (patrón III). La identificación de NSE mediante ecografía fue correcta en casi el 90 %. El diámetro del NSE con el patrón I fue el más grande en comparación con los de los otros dos patrones. En el patrón I, NSE corría lateralmente desde la parte superior del tronco del plexo braquial y pasaba por debajo del vientre inferior del músculo omohioideo. Por lo tanto, el NSE se identificó fácilmente mediante ecografía. En el patrón II, el nervio identificado por ecografía era literalmente el nervio escapular dorsal; en el patrón III, el NSE no pudo ser identificado debido a su variación anatómica. La precisión de la identificación ecográfica del NSE en la fosa supraclavicular es alta y los puntos de referencia sonoanatómicos clave son el borde lateral del plexo braquial y el vientre inferior del músculo omohioideo. Las variantes anatómicas de NSE son razones de identificación incorrecta o incapaz de NSE bajo ecografía.

Origin and distribution of the lumbosacral plexus anatomy in van cats / Origen y distribución de la anatomía del plexo lumbosacro en gatos van

SUMMARY: The innervation of the pelvic limbs of the Van cat is investigated in this research. The origins of the nerves, the innervated muscles and nerve diameters were shown in a table. Five cat cadavers were used in the study. The pudendal nerve originated from the S1-S2 spinal nerves. The femoral nerve consisted of the ventral branches of the 5th and 6th lumbar nerves in 4 cats The ischiatic nerve was composed of the 6th and 7th lumbar (L6-L7) and S1 spinal nerves in all cadavers. The ischiatic nerve was the thickest branch of sacral plexus (the average diameter on the right side was 3.31 ± 0.27 mm and the average diameter on the left side was 3.28 ± 0.29 mm). The lumbosacral plexus was formed by the ventral branches of the L4-S3 spinal nerves. N.genitofemoralis consisted of only the ventral branches of L4 in all cadavers. N. femoralis did not give rise to a branch to the m. iliopsoas. N.plantaris lateralis was found to give a branch to the 3th finger. The quadriceps femoris muscles did not take any branches from either the ischiadicus nerve or the pudendal nerve. The obturator nerve did not receive any branches from the L4 spinal nerves. There was no branch to the skin from the caudal gluteal nerve. The thinnest nerve was the pudendal nerve. Due to the scarcity of studies on the lumbosacral plexus of cats, it is thought that this study will complete a gap in the field of veterinary anatomy.

RESUMEN: En esta investigación se estudió la inervación de los miembros pélvicos del gato Van. Los orígenes de los nervios, los músculos inervados y los diámetros de los nervios son mostrados en una tabla. En el estudio se utilizaron cinco cadáveres de gatos. En cuatro gatosel nervio pudendo se originaba a partir de los nervios espinales S1-S2. El nervio femoral consistió en los ramos ventrales de los nervios lumbares quinto y sexto. El nervio isquiático estaba compuesto por los nervios espinales sexto y séptimo lumbar (L6-L7) y S1 en todos los cadáveres. El nervio isquiático era el ramo más grueso del plexo sacro (el diámetro medio del lado derecho medía de 3,31 ± 0,27 mm y el diámetro medio izquierdo 3,28 ± 0,29 mm). El plexo lumbosacro estaba formado por los ramos ventrales de los nervios espinales L4-S3. N. genitofemoralis constaba solo de las ramas ventrales de L4 en todos los cadáveres. N. femoralis no dio lugar a un ramo a la m. iliopsoas. Los músculos del cuádriceps femoral no tomaron ningún ramo ni del nervio isquiático ni del nervio pudendo. El nervio obturador no recibió ramos de los nervios espinales L4. No existían ramos a la piel desde el nervio glúteo caudal. El nervio más delgado fue el nervio pudendo. Debido a la escasez de estudios sobre el plexo lumbosacro de los gatos, este estudio completará un vacío en el campo de la anatomía veterinaria.

Anatomical basis for the selective block of the nerve to quadratus femoris by way of percutaneous techniques / Bases anatómicas para el bloque selectivo del nervio del músculo cuadrado femoral a través de técnicas percutáneas

SUMMARY: Hip joint chronic pain can severely compromise patients' life quality. Peripheral nerve blocks play an important role as diagnostic and therapeutic procedures. The aim of this work is to study the anatomy of the nerve to quadratus femoris (NQF) in view of the possibility of its percutaneous selective block. Forty-three gluteal cadaveric regions fixed in formaldehyde solution were dissected. The quadratus femoris, the obturator internus and superior and inferior gemellus were freed from their lateral insertion, exposing thus the posterior aspect of the hip joint. The NQF was identified, and the horizontal distance to the posterior edge of the greater trochanter at its upper, middle and lower thirds was registered. The number of the articular branches of the NQF was identified. Likewise, the horizontal distance to the posterior edge of the greater trochanter and the longitudinal distance to the line through the distal end of the posterior edge of the greater trochanter were measured. The distance between the NQF and the greater trochanter posterior edge at upper, middle and lower thirds was 46 mm, 41 mm and 35 mm, respectively. In most cases (85 %) the NQF presented one or two articular branches. The longitudinal distances between the line through the distal end of the posterior edge of the greater trochanter and the origin of the first, second and third articular branches of the NQF were 14.7 mm (-19.4 - 40), 16.4 mm (-9.3-42) and 27 mm (0-46), respectively. The distances to the posterior edge of the greater trochanter were 43.1 mm (16.3-66), 37.7 mm (6.5-53) and 39.8 mm (26-52), for the first, second and third articular branches, respectively. In conclusion, the articular branches of the nerve to quadratus femoris have a constant and predictable distribution. Our findings allow for generating a coordinate system for the selective block of the NQF by way of percutaneous techniques.

RESUMEN: El dolor crónico de la articulación coxal puede comprometer severamente la calidad de vida de los pacientes. Los bloqueos nerviosos periféricos juegan un papel importante como procedimientos diagnósticos y terapéuticos. El objetivo de este trabajo es estudiar la anatomía del nervio del músculo cuadrado femoral (NCF) en vista de la posibilidad de su bloqueo selectivo percutáneo. Se utilizaron 22 cadáveres fijados en solución de formaldehído. Fueron disecadas en total 43 regiones glúteas. Los músculos cuadrado femoral, obturador interno y los gemelos superior e inferior fueron liberados de su inserción lateral, exponiendo así la cara posterior de la articulación coxal. Se identificó el NCF y se registró la distancia horizontal al margen posterior del trocánter mayor en sus tercios superior, medio e inferior. Se identificó el número de ramas articulares del NQF. Asimismo, se midió la distancia horizontal al margen posterior del trocánter mayor y la distancia longitudinal a la línea que pasa por el extremo distal del margen posterior del trocánter mayor. La distancia entre el NCF y el margen posterior del trocánter mayor en los tercios superior, medio e inferior fue de 46 mm, 41 mm y 35 mm, respectivamente. En la mayoría de los casos (85 %) el NCF presentó una o dos ramas articulares. Las distancias longitudinales entre la línea que pasa por el extremo distal del margen posterior del trocánter mayor y el origen de la primera, segunda y tercera ramas articulares del NQF fueron 14,7 mm (-19,4 - 40), 16,4 mm (-9,3-42) y 27 mm (0-46), respectivamente. Las distancias al margen posterior del trocánter mayor fueron 43,1 mm (16,3-66), 37,7 mm (6,5-53) y 39,8 mm (26-52), para la primera, segunda y tercera ramas articulares, respectivamente. En conclusión, las ramas articulares del nervio al cuadrado femoral tienen una distribución constante y predecible. Nuestros hallazgos permiten generar un sistema de coordenadas para el bloqueo selectivo del NCF por medio de técnicas percutáneas.

Localization of the centers of intramuscular nerve dense regions of the rotator cuff muscles: a guide for botulinum toxin A injection for spasticity accompanied by shoulder pain / Localización de los centros de las regiones densas del nervio intramuscular de los músculos del manguito rotador: una guía para la inyección de toxina botulínica A por espasticidad con dolor de hombro

To accurately localize the centers of intramuscular nerve dense regions (CINDRs) of rotator cuff muscles. Twenty adult cadavers were used. The curves on skin connecting the superior angle of scapula with the acromion, and with the inferior angle of scapula were designed as the horizontal (H) and longitudinal (L) reference lines, respectively. One side of the rotator cuff muscles were removed and subjected to Sihler's staining to show intramuscular nerve dense regions, and the contralateral muscles' CINDRs were labeled with barium sulfate and scanned by computed tomography (to determine body surface projection points (P)). The intersection of the longitudinal line from point P to line H, and that of the horizontal line from point P to line L, were recorded as PH and PL, respectively. The projection of CINDRs on the anterior body surface across the saggital plane was defined as P' and the line connecting P to P' was recorded as Line PP'. Percentage positions of CINDRs of PH and PL on lines H and L, and the depths on line PP' were determined under the Syngo system. Two, four, one, and one CINDRs were identified in supraspinatus, infraspinatus, teres minor, and subscapularis muscles, respectively. The positions of PH of these CINDRs on the H-line are as follows: supraspinatus, 25.43 % and 26.59 %; infraspinatus, 53.85 %, 34.63 %, 35.96 % and 58.17 %; teres minor, 74.50 %; and subscapularis, 20.33 %. The PL on the L-line: supraspinatus, 11.09 % and 14.83 %; infraspinatus, 21.59 %, 27.93 %, 48.55 % and 57.52 %; teres minor, 68.28 %; and subscapularis, 52.82 %. The depth on line PP': supraspinatus, 24.83 % and 25.40 %; infraspinatus, 21.55 %, 16.10 %, 10.01 % and 8.14 %; teres minor, 13.27 %; and subscapularis, 22.88 %. The identification of these CINDRs should provide the optimal target position for injecting botulinum toxin A to treat rotator cuff muscles spasticity accompanied by shoulder pain and to improve the efficiency and efficacy of blocking target localization.

Con el objetivo de localizar con precisión los centros de las regiones densas del nervio intramuscular (CRDNI) de los músculos del manguito rotador, se utilizaron veinte cadáveres adultos. Las curvas en la piel que conectan el ángulo superior de la escápula con el acromion y con el ángulo inferior de la escápula se determinaron como líneas de referencia horizontales (H) y longitudinales (L), respectivamente. Se extrajo de un lado los músculos del manguito rotador y se sometió a la tinción de Sihler para mostrar regiones densas de nervios intramusculares, y los CRDNI de los músculos contralaterales se marcaron con sulfato de bario y se escanearon mediante tomografía computarizada (para determinar los puntos de proyección de la superficie corporal (P)). La intersección de la línea longitudinal desde el punto P a la línea H, y de la línea horizontal desde el punto P a la línea L, se registraron como PH y PL, respectivamente. La proyección de CRDNI en la superficie del cuerpo anterior a través del plano sagital se definió como P 'y la línea que conecta P a P' se registró como Línea PP '. Las posiciones porcentuales de los CRDNI de PH y PL en las líneas H y L, y las profundidades en la línea PP 'se determinaron bajo el sistema Syngo. Se identificaron dos, cuatro, uno y un CINDR en los músculos supraespinoso, infraespinoso, redondo menor y subescapular, respectivamente. Las posiciones de PH de estos CRDNI en la línea H son las siguientes: supraespinoso, 25,43 % y 26.59 %; infraspinatus, 53,85 %, 34,63 %, 35,96 % y 58,17 %; redondo menor, 74,50 %; y subescapular, 20,33 %. El PL en la línea L: supraespinoso, 11.09 % y 14.83 %; infraspinatus, 21,59 %, 27,93 %, 48,55 % y 57,52 %; redondo menor, 68.28 %; y subescapular, 52,82 %. La profundidad en la línea PP ': supraespinoso, 24,83 % y 25,40 %; infraspinatus, 21,55 %, 16,10 %, 10,01 % y 8,14 %; redondo menor, 13.27 %; y subescapularis, 22,88 %. La identificación de estos CRDNI debería proporcionar la posición objetivo óptima para inyectar la toxina botulínica A para tratar la espasticidad de los músculos del manguito rotador acompañada de dolor en el hombro y para mejorar la eficiencia y la eficacia del bloqueo de la localización del objetivo.

The need for supplemental blocks in single versus triple injections in infraclavicular brachial plexus blocks with a medial approach: a clinical and anatomic study / Bloqueio complementar de nervos no bloqueio de plexo braquial infraclavicular com técnica medial de injeção única versus tripla: estudo anátomo-clínico

Abstract Background and objectives: To evaluate the single-injection and triple-injection techniques in infraclavicular blocks with an ultrasound-guided medial approach in terms of block success and the need for supplementary blocks. Methods: This study comprised 139 patients who were scheduled for elective or emergency upper-limb surgery. Patients who received an infraclavicular blocks with a triple-injection technique were included in Group T (n = 68). Patients who received an infraclavicular blocks with a single-injection technique were included in Group S (n = 71). The number of patients who required supplementary blocks or had complete failure, the recovery time of sensory blocks and early and late complications were noted. Results: The block success rate was 84.5% in Group S, and 94.1% in Group T without any need for supplementary nerve blocks. The blocks were supplemented with distal peripheral nerve blocks in 8 patients in Group S and in 3 patients in Group T. Following supplementation, the block success rate was 95.8% in Group S and 98.5% in Group T. These results were not statistically significant. A septum preventing the proper distribution of local anesthetic was clearly visualized in 4 patients. The discomfort rate during the block was significantly higher in Group T (p < 0.05). Conclusion: In ultrasound-guided medial-approach infraclavicular blocks, single-injection and triple-injection techniques did not differ in terms of block success rates. The need for supplementary blocks was higher in single injections than with triple injections. The presence of a fascial layer could be the reason for improper distribution of local anesthetics around the cords.

Resumo Justificativa e objetivos: Avaliar as técnicas de injeção única e tripla no bloqueio infraclavicular, empregando-se acesso medial guiado por ultrassonografia, comparando-se o sucesso do bloqueio e a necessidade de bloqueios complementares. Método: O estudo incluiu 139 pacientes com indicação de cirurgia de membro superior eletiva ou de emergência. O Grupo T (n = 68 pacientes) recebeu bloqueio infraclavicular com técnica de injeção tripla e o Grupo S (n = 71), bloqueio infraclavicular com injeção única. Registrou-se o número de pacientes que necessitaram bloqueio complementar de nervo ou que apresentaram falha completa do bloqueio, o tempo de recuperação do bloqueio sensorial e as complicações precoces e tardias. Resultados: A taxa de sucesso do bloqueio infraclavicular, sem necessidade de bloqueio complementar de nervo, foi 84,5% e 94,1% para os Grupos S e T, respectivamente. No bloqueio infraclavicular foi necessário bloqueio de nervos periféricos distais em 8 e 3 pacientes dos Grupos S e T, respectivamente. Após a complementação, a taxa de sucesso do bloqueio foi 95,8% e 98,5% para os Grupos S e T, respectivamente. Os resultados não foram estatisticamente significantes. Imagem de septo impedindo a distribuição adequada do anestésico local foi claramente visualizada em quatro pacientes. A taxa de desconforto durante a realização do bloqueio foi estatatisticamente mais alta no Grupo T (p< 0,05). Conclusões: As técnicas de injeção única e tripla em bloqueio infraclavicular guiado por ultrasonografia com acesso medial não diferiram quanto à taxa de sucesso. A necessidade de bloqueio complementar foi maior com a técnica de injeção simples. A ocorrência de invólucro de fascia poderia justificar a distribuição inadequada do anestésico local ao redor dos fascículos do plexo.

Origen del nervio subescapular inferior, patrones de ramificación y su contribución a la inervación del músculo subescapular / Origin of the inferior subscapular nerve, branching patterns and its contribution to the subscapular muscle innervation

El nervio subescapular inferior (NSI) inerva parcialmente al músculo subescapular (MSe) e inerva también al músculo redondo mayor (MRM). Diversas publicaciones determinan amplia variación en su origen en el Plexo Braquial (PB), pero existe poca evidencia de estas variaciones y del patrón de inervación del MSe y MRM en individuos latinoamericanos. El propósito de este estudio fue describir el origen del NSI en el PB, determinar número de ramos que le entrega al MSe y los patrones de ramificación. Se utilizaron 30 miembros superiores de individuos adultos, Brasileños; 13 del lado derecho y 17 del izquierdo, fijados en formaldehido al 10 %. Se disecaron las regiones axilares para exponer el fascículo posterior del plexo braquial (FPPB) y sus ramos. Se determinó si el origen del NSI era individual o procedía de un tronco común. Se cuantificó el número de ramos para el MSe, estableciendo patrones de ramificación. El NSI y sus ramos se agruparon según su origen y ramificación. En 3 de los casos (10 %) el NSI procedía de un tronco común con el nervio toracodorsal (NTD), 2 del lado izquierdo (6,6 %) y 1 del derecho (3,3 %); en 27 casos (90 %) procedía del nervio axilar (NAx), 15 del lado izquierdo (50 %) y 12 del derecho (40 %). En ningún caso, el origen fue directo del FPPB. Además, se cuantificó el número de ramos que aportaba a la inervación del MSe, observándose un promedio de 4 ramos (de 1 a 8 ramos) para el MSe. Se identificaron 4 patrones de ramificación del NSI hacia el MSe y el MRM. Tanto el origen como la distribución del NSI presentaron variaciones. Los datos aportados complementarán los conocimientos para la correcta enseñanza, el oportuno diagnóstico y la buena práctica quirúrgica de la zona axilar.

The inferior subscapular nerve (ISN) partially innervates the subscapular muscle (SbM) and also innervates the teres major muscle (TMM). Several publications determine wide variation in their origin from Brachial Plexus (BP), but there is little evidence of these variations and the innervation pattern of SbM and TMMin Latin American individuals. The purpose of this study was to describe the origin of the ISN from PB, to determine the number of branches that it gives to the SbM and the branching patterns. 30 upper limbs of cadavers of the Brazilian adult individuals were used; 13 on the right side and 17 on the left, fixed in 10 % formaldehyde. The axillary regions were dissected to expose the posterior fascicle of the brachial plexus (PFBP) and its branches. It was determined whether the origin of the NSI was individual or came from a common trunk. The number of branches for the SbM was quantified, establishing branching patterns. The ISN and its branches were grouped according to their origin and branching. In 3 of the cases (10 %) the ISN came from a common trunk with the thoracodorsal nerve (TDN), 2 from the left side (6.6 %) and 1 from the right side (3.3 %); in 27 cases (90 %) it came from the axillary nerve (AxN), 15 from the left side (50 %) and 12 from the right side (40 %). In no case, the origin was direct from the PFBP. In addition, the number of branches that contributed to the innervation of the SbM was quantified, with an average of 4 branches (from 1 to 8 branches) being observed for the SbM. Four branching patterns of the ISN towards the SbM and the TMM were identified. Both the origin and the distribution of the ISN presented many variations. The data provided will complement the knowledge for proper teaching, timely diagnosis and good surgical practice of the axillary area.

Anatomical study of the branch of the palmaris longus muscle for its transfer to the posterior interosseous nerve / Estudio anatómico del ramo del músculo palmar largo para su transferencia al nervio interóseo posterior

The objective of the study was to evaluate the anatomical characteristics and variations of the palmaris longus nerve branch and define the feasibility of transferring this branch to the posterior interosseous nerve without tension. Thirty arms from 15 adult male cadavers were dissected after preparation with 20 % glycerin and formaldehyde intra-arterial injection. The palmaris longus muscle (PL) received exclusive innervation of the median nerve in all limbs. In most it was the second muscle of the forearm to be innervated by the median nerve. In 5 limbs the PL muscle was absent. In 5 limbs we identified a branch without sharing branches with other muscles. In 4 limbs it shared origin with the pronator teres (PT), in 8 with the flexor carpi radialis (FCR), in 2 with flexor digitorum superficialis (FDS), in 4 shared branches for the PT and FCR and in two with PT, FCR, FDS. The mean length was (4.0 ± 1.2) and the thickness (1.4 ± 0.6). We investigated whether the branch for PL was long enough to be transferred to the posterior interosseous nerve (PIN). The branch diameter for PL corresponds to 46 % of the PIN. The PL muscle branch presented great variability. The PL branch could be transferred to the PIN proximally to the Froshe arcade without tension in all specimens even with full range of motion of the forearm. In 13 limbs was possible the tensionless transfer to PIN distal to the branches of the supinator muscle.

El objetivo de este estudio fue evaluar las características anatómicas y las variaciones del ramo del músculo palmar largo y definir la posibilidad de transferir este ramo al nervio interóseo posterior sin tensión. Se disecaron 30 miembros superiores de 15 cadáveres de hombres adultos después de su preparación con 20 % de glicerina y formaldehído, inyectados por vía intraarterial. En todos los miembros el músculo palmar largo (PL) recibió inervación exclusiva del nervio mediano. En la mayoría de los casos, fue el segundo músculo del antebrazo inervado por el nervio mediano. En 5 miembros estaba ausente el músculo. En 5 miembros identificamos un ramo sin compartir ramos con otros músculos. En 4 miembros, compartió el origen con el músculo pronador redondo (PR), en 8 con el músculo flexor radial del carpo (FRC), en 2 con el músculo flexor superficial de los dedos (FCSD), en 4 ramos compartidos para el PR y FRC y en dos con PR, FRC, FCSD. La longitud media fue (4,0±1,2 cm) y el grosor (1,4±0,6 cm). Investigamos si el ramo del PL era lo suficientemente largo para ser transferido al nervio interóseo posterior (NIP). El diámetro del ramo para el PL corresponde al 46 % del NIP. El ramo del músculo PL presentó una gran variabilidad. El ramo del PL podría transferirse al NIP proximalmente a la «arcada de Frohse¼, sin tensión, en todas las muestras, incluso con el rango completo de movimiento del antebrazo. En 13 miembros fue posible la transferencia sin tensión al NIP distal a los ramos del músculo supinador.

Descrição anatômica do plexo braquial de Callithrix jacchus e Callithrix penicillata / Anatomic description of brachial plexus of Callithrix jacchus and Callithrix penicillata

Callithrix jacchus e Callithrix penicillata são primatas de pequeno porte cuja utilização como modelo anatômico tem se mostrado cada vez mais frequente, não somente pela praticidade no manuseio como facilidade no trato em criatório e sua taxa de reprodução. Este estudo teve como objetivo descrever os componentes dos plexos braquial em Callithrix jacchus e penicillata. Para tanto, três espécimes com aproximadamente 8 anos e 240 g foram fixados em solução de formaldeído a 10%, e posteriormente dissecados e fotodocumentados. O plexo braquial do Callithrix jacchus e penicillata originou-se dos nervos espinhais C5 a T1 constituindo os troncos cranial, médio e caudal. A composição do plexo braquial destes animais se assemelha ao de outros primatas, bem como a outros mamíferos.(AU)

Callithrix jacchus and Callithrix penicillata are small primates used as anatomic model, not only for convenience in handling as ease in regard to breeding and reproductive rate. The aim of this study was to describe the components of the brachial plexus in Callithrix jacchus and C. penicillata. Three specimens about 8 years old and weighing 240g were fixed in 10% formaldehyde and subsequently dissected and photodocumented. The brachial plexus of Callithrix jacchus and C. penicillata originates from the spinal nerves C5 to T1 in continuation of the cranial, medium and flow trunk. The composition of the brachial plexus of these animals is similar to the one of other primates ands other mammals.(AU)

Nervios digitales palmares comunes del ramo superficial del nervio ulnar y nervios digitales plantares comunes del ramo superficial del nervio plantar lateral: un error anatómico en terminologia anatomica / Common palmar digital nerves from the superficial branch of the ulnar nerve and common plantar digital nerves from superficial branch of the lateral nerve: an anatomical error in terminologia anatomica

Terminologia Anatomica contempla la existencia de nervios digitales palmares comunes del ramo superficial del nervio ulnar y nervios digitales plantares comunes del ramo superficial del nervio plantar lateral. De acuerdo a la mayoría de los textos clásicos y estudios anatómicos de las regiones de la palma de la mano y de la planta del pie, solo existiría un nervio digital palmar común (IV) originado del ramo superficial del nervio ulnar y un nervio digital plantar común (IV) con origen en el ramo superficial del nervio plantar lateral. Realizamos una revisión anatómica de la inervación cutánea de la palma de la mano observando el comportamiento de los nervios mediano y ulnar y de la planta del pie a través de los nervios plantares medial y lateral, comentamos la literatura relacionada y concluimos que debe corregirse la Terminologia Anatomica, en el término A14.2.03.046(Nn. digitales palmares comunes) y en el término A14.2.07.071(Nn. digitales plantares comunes), los cuales deberían denominarse N. digital palmar común y N. digital plantar común, ambos corresponderían al IV nervio digital palmar común y IV nervio digital plantar común, respectivamente.

Terminologia Anatomica contemplates the existence of common palmar digital nerves from the superficial branch of the ulnar nerve and common plantar digital nerves from the superficial branch of the lateral plantar nerve. According to most classical texts and anatomical studies of the regions palmar and plantar, there would only be common palmar digital nerve (IV) originated from the superficial branch of the ulnar nerve and common plantar digital nerve (IV) arising from the superficial branch of lateral plantar nerve. We conducted an anatomical review of the cutaneous innervation of the palm observing the behavior of the median and ulnar nerves, and the foot through the medial and lateral plantar nerves. In this study we discuss the related literature and conclude that Terminologia Anatomica must be corrected in the A14.2.03.046 term (Nn. common palmar digital) and in A14.2.07.071 term (Nn. common plantar digital ), which should be called: common palmar digital nerve and common plantar digital nerve, corresponding to both the IV common palmar digital nerve and IV common plantar digital nerve, respectively.

Sartorial branch of saphenous nerve: anatomical relationship with bony landmarks and great saphenous vein / Ramo sartorial del nervio safeno safeno: relación anatómica con puntos de referencia óseos y de la vena safena magna

Sartorial branch of saphenous nerve (medial crural cutaneous nerve) originates at the medial side of the knee and descends along the great saphenous vein (GSV) to innervate the medial aspect of the leg. Its anatomy is of concern in surgical procedures and anesthetic block. However, the measurement data related to palpable bony landmarks with comparison between sexes and sides are lacking. Dissection was done in 95 lower limbs from both sexes. We found that the nerve pierced the deep fascia alone in most cases (92.6%). This piercing point was always distal to the adductor tubercle with the distance of 5-6 cm which was 15% of the leg length (the distance between the adductor tubercle and medial malleolus). The nerve was 7 cm medial to the tibial tuberosity. At the mid-level of leg length, the nerve was slightly over 4 cm medial to the anterior tibial margin. The nerve terminally divided 7 cm proximal to the medial malleolus. Furthermore, the anatomical relationship between the nerve and the GSV was highly variable. The nerve was constantly anterior, posterior or deep to the GSV in 8.4%, 15.8% and 2.1%, respectively. Crossing between the two structures was observed in 57.9% of specimens and the distance to the medial malleolus was 18 cm. Symmetry was found in most parameters and significant gender differences were observed in some distances. These results are important for avoiding the sartorial nerve injury and locating the nerve during relevant procedures.

El ramo sartorial del nervio safeno (nervio cutáneo medial de la pierna) se origina en el lado medial de la rodilla y desciende a lo largo de la vena safena magna (VSM) para inervar la cara medial de la pierna. Su anatomía es motivo de preocupación en los procedimientos quirúrgicos y en el bloqueo anestésico. Sin embargo, los datos de medición relacionados con puntos de referencia óseos palpables y la comparación entre los lados y en ambos sexos son escasas. Se realizó la disección en 95 miembros inferiores de ambos sexos. Se encontró que el nervio perforó la fascia profunda en la mayoría de los casos (92,6%). Esta punta de perforación fue siempre distal al tubérculo del músculo aductor magno a una distancia de 5-6 cm, que representaba el 15% del largo de la pierna (la distancia entre el tubérculo del aductor magno y el maléolo medial). El nervio se localizaba 7 cm medial a la tuberosidad tibial. Al nivel del tercio medio en ambas piernas, el nervio estaba a una distancia un poco mayor a 4 cm medial al margen anterior de la tibia. El nervio se dividía 7 cm proximal al maléolo medial. Por otra parte, la relación anatómica entre el nervio y la VSM fue muy variable. El nervio era constantemente anterior, posterior o profundo a la VSM en 8,4%, 15,8% y 2,1%, respectivamente. Cruce entre las dos estructuras anatómicas se observó en el 57,9% de las muestras y la distancia hasta el maléolo medial fue de 18 cm. La simetría se encuentra en la mayoría de los parámetros y diferencias de sexo significativas se observaron en algunas distancias. Estos resultados son importantes para evitar la lesión del nervio sartorial y localizar el nervio durante los procedimientos pertinentes.

Bloqueio do nervo supraescapular: procedimento importante na prática clínica / Suprascapular nerve block: important procedure in clinical practice

JUSTIFICATIVA E OBJETIVOS: A dor no ombro é uma queixa frequente que ocasiona grande incapacidade funcional no membro acometido, assim como redução na qualidade de vida dos pacientes. O bloqueio do nervo supraescapular é um método terapêutico eficaz e vem sendo cada vez mais utilizado pelos anestesiologistas tanto para anestesia regional quanto para analgesia pós-operatória de cirurgias realizadas nesta articulação, o que justifica a presente revisão, cujo objetivo principal é descrever a técnica aplicada e as indicações clínicas. CONTEÚDO: Apresenta-se a anatomia do nervo supraescapular, desde a sua origem do plexo braquial até os seus ramos terminais, assim como as características gerais e a técnica empregada na execução do bloqueio deste nervo, as principais drogas utilizadas e o volume e as situações em que se faz jus a sua aplicação. CONCLUSÕES: O bloqueio do nervo supraescapular é um procedimento seguro e extremamente eficaz na terapia da dor no ombro. Também de fácil reprodutibilidade, está sendo muito utilizado por profissionais de várias especialidades médicas. Quando bem indicado, este método deve ser considerado.

BACKGROUND AND OBJECTIVES: Shoulder pain is a frequent complaint that results in great functional disability in the affected shoulder as well as the decrease in patients' quality of life. Suprascapular nerve block is an effective therapeutic method and has been increasingly used by anesthesiologists both for regional anesthesia and postoperative analgesia of surgeries carried out in this articulation, which justifies this review, whose main purpose was to describe the applied technique and clinical indications. CONTENT: It is presented the anatomy of suprascapular nerve, since its brachial plexus origin until its terminal branches, as well as general characteristics and technique employed to carry out the block of this nerve, main drugs used, volume and situations that give rise to its applications. CONCLUSIONS: Suprascapular nerve block is a safe and extremely effective procedure in shoulder pain therapy. It also has an easy reproducibility and has been very used by professionals of many medical specialties. When it is well-indicated, this method must be taken into consideration.

JUSTIFICATIVA Y OBJETIVOS: El dolor en el hombro es un quejido frecuente que ocasiona una gran incapacidad funcional en el miembro perjudicado, como también la reducción en la calidad de vida de los pacientes. El bloqueo del nervio supraescapular es un método terapéutico eficaz y ha venido siendo cada vez más utilizado por los anestesiólogos tanto para la anestesia regional como para la analgesia postoperatoria de cirugías realizadas en esa articulación, lo que justifica la presente revisión cuyo objetivo principal es describir la técnica aplicada y las indicaciones clínicas. CONTENIDO: Presentamos la anatomía del nervio supraescapular, desde su origen, y desde el plexo braquial hasta sus ramas terminales, como también las características generales y la técnica usada en la ejecución del bloqueo de ese nervio, los principales fármacos utilizados y el volumen y las situaciones en que se justifica su aplicación. CONCLUSIONES: El bloqueo del nervio supraescapular es un procedimiento seguro y extremadamente eficaz en la terapia del dolor en el hombro. También es fácilmente reproducible y está siendo muy utilizado por profesionales de varias especialidades médicas. Cuando está bien indicado, el método debe ser tenido en cuenta.

Neuroanatomical Study of Periprostatic Nerve Distributions Using Human Cadaver Prostate

We investigated the distribution and navigation of periprostatic nerve fibers and constructed a 3-dimensional model of nerve distribution. A total of 5 cadaver specimens were serially sectioned in a transverse direction with 0.5 cm intervals. Hematoxylineosin staining and immunohistochemical staining were then performed on whole-mount sections. Three representative slides from the base, mid-part, and apex of each prostate were subsequently divided into 4 sectors: two lateral, one ventral, and one dorsal (rectal) part. The number of nerve fibers, the distance from nerve fiber to prostate capsule, and the nerve fiber diameters were analyzed on each sector from the representative slides by microscopy. Periprostatic nerve fibers revealed a relatively even distribution in both lateral and dorsal parts of the prostate. There was no difference in the distances from the prostate capsule to nerve fibers. Nerve fibers in the ventral area were also thinner as compared to other areas. In conclusion, periprostatic nerve fibers were observed to be distributed evenly in the periprostatic area, with the exception of the ventral area. As the number of nerve fibers on the ventral part is fewer in comparison, an excessive high up incision is insignificant during the nerve-sparing radical prostatectomy.

Anatomical Consideration of the Anterior and Lateral Cutaneous Nerves in the Scalp

To better understand the anatomic location of scalp nerves involved in various neurosurgical procedures, including awake surgery and neuropathic pain control, a total of 30 anterolateral scalp cutaneous nerves were examined in Korean adult cadavers. The dissection was performed from the distal to the proximal aspects of the nerve. Considering the external bony landmarks, each reference point was defined for all measurements. The supraorbital nerve arose from the supraorbital notch or supraorbital foramen 29 mm lateral to the midline (range, 25-33 mm) and 5 mm below the supraorbital upper margin (range, 4-6 mm). The supratrochlear nerve exited from the orbital rim 16 mm lateral to the midline (range, 12-21 mm) and 7 mm below the supraorbital upper margin (range, 6-9 mm). The zygomaticotemporal nerve pierced the deep temporalis fascia 10 mm posterior to the frontozygomatic suture (range, 7-13 mm) and 22 mm above the upper margin of the zygomatic arch (range, 15-27 mm). In addition, three types of zygomaticotemporal nerve branches were found. Considering the superficial temporal artery, the auriculotemporal nerve was mostly located superficial or posterior to the artery (80%). There were no significant differences between the right and left sides or based on gender (P>0.05). These data can be applied to many neurosurgical diagnostic or therapeutic procedures related to anterolateral scalp cutaneous nerve.

Viability of nerve grafts preserved in different storage medium: ultrastructural features

We investigated the ultrastructural organization of transplanted autologous grafts after storage in two different solutions. Male Wistar rats were divided into groups to obtain normal tibial nerves, freshly transplanted nerves, and nerves stored in Wisconsin/Belzer or Collins solution for 24 or 72 hours at 4 °C and transplanted (W1, W3, C1, C3). After storage or transplantation, the specimens were processed for ultrastructural analysis. All grafts showed alterations in collagen fiber organization in the endoneurial space compared to normal nerves. These fibers were more loosely organized among nerve fibers, a finding that was significantly more marked in group C3 compared to groups W1 and W3. Important alterations were also observed in the myelin sheath structure of grafts stored in the two media. These changes were characterized by separation of the lipid lamellae, clearly visible in larger diameter nerve fibers. These findings were more marked and frequent in the C1 and C3 groups compared to the W1 and W3 groups. Ultrastructural analysis showed better preservation of Schwann cells and other elements that support axonal regeneration for grafts stored in Wisconsin/Belzer solution. These results support ongoing studies for the formulation of storage solutions that permit the creation of nerve banks for heterologous transplantation.

Tubo de ácido poliglicólico e GM1 na regeneração de nervos periféricos / Polyglycolic acid tube associated with GM1 in regeneration of peripheral nerves

INTRODUÇÃO: A auto-enxertia de nervo é considerada tratamento de escolha nas grandes perdas de tecido neural que não permitam a reparação através de anastomose primária. Nesses casos, o tubo sintético à base de ácido poliglicólico é uma alternativa para enxertia de nervo. Por outro lado, muitos estudos têm enfatizado a importância dos fatores neurotróficos na regeneração neural: o monossialotetraesosilgangliosídeo (GM1), um dos principais glicoesfingolípides do tecido nervoso de mamíferos, é tido como potencializador dos efeitos desses fatores. OBJETIVO: Comparar, em ratos, o grau de regeneração neural, utilizando análise histológica, contagem do número de axônios mielinizados regenerados e análise funcional com a utilização do neurotubo e do GM1. MÉTODOS: Essa avaliação foi obtida com a interposição de enxerto autógeno (grupo A), tubo de ácido poliglicólico (grupo B) e da associação do tubo de ácido poliglicólico à administração de GM1 (grupo C) em defeitos de 5 mm no nervo ciático. RESULTADOS: Foi observada formação de neuroma apenas no grupo A. Os grupos A e C apresentaram padrões histológicos semelhantes, exceto que os axônios regenerados do grupo C apresentavam-se mais organizados e mielinizados que o grupo A. CONCLUSÃO: Na recuperação funcional, não houve diferença estatisticamente significativa entre os três grupos, a despeito das diferenças histológicas qualitativas e quantitativas verificadas.

INTRODUCTION: Nerve allografting is regarded as a treatment of choice in large neural tissue losses preventing repair by primary anastomosis. In these cases, a synthetic polyglycolic acid tube is an alternative for nerve grafting. On the other hand, several studies have emphasized the importance of neurotrophic factors on neural regeneration, including substances with potential to optimize neural regeneration, especially the GM1, an neurotrophic enhancer factor. OBJECTIVE: to compare, in rats, the neural regeneration degree using histological analysis, regenerated myelinized axons count, and functional analysis with the use of neurotube and GM1. METHODS: This assessment was performed by interposing allograft (group A), polyglycolic acid tube (group B) and polyglycolic acid tube associated to GM1 (group C) on 5-mm sciatic nerve defects. RESULTS: Neuroma formation was found only on group A. Groups A and C showed similar histological patterns, except for the regenerated axons on group C, which were shown to be better organized and myelinized than in group A. CONCLUSION: on functional recovery, no statistically significant difference was found for the three groups, despite of qualitative and quantitative histological differences found.

Estimulación nerviosa periférica: análisis de la respuesta motora en diferentes circunstancias experimentales / Peripheral nerve stimulation: motor response analysis in different experimental circumstances

Introducción. Con una aguja aislada, en aparente contacto nervioso testeado por ultrasonido (US) o por la referencia de una parestesia, no se consigue respuesta motora (RM) a la estimulación nerviosa en un porcentaje variable de casos. El objetivo de nuestros estudios fue observar el comportamiento de la RM a valores < 1mA / 0.1 mseg en diferentes circunstancias experimentales. Aportar evidencia científica que contribuya determinar si con técnica usual de estimulación nerviosa (NS) un nervio puede contactarse o penetrarse sin obtenerse antes una RM. Material y Métodos. Bajo visión directa, doce nervios ciáticos de diferentes animales fueron expuestos y estimulados en dos mitades imaginarias. Observadores ciegos a la intensidad utilizada, consignaron la RM obtenida con 1 mA / 0.1 mseg sin y con contacto nervioso; y con 0.5 mA en contacto; el valor mínimo de intensidad en contacto con que aparece una RM y se obtiene una RM Grado 2, el comportamiento de la RM con la inyección anestésica local (AL) extraneural y la necesidad de aumentar o no la intensidad para obtener una RM de igual intensidad. Luego de colocar la aguja intraneural, se aumentó la intensidad hasta obtener una primer RM y una RM Grado 2. Finalmente se inyectó el AL intraneural y se consignó el comportamiento de la RM. Resultados. Sin contacto nervioso con 1 mA, se obtuvo RM en el 91.6 por ciento de los intentos en ambas mitades del nervio ciático y en el 100 por ciento con contacto neural. Con 0.5 mA en contacto, no se consiguió RM en una mitad en 33.3 por ciento de los intentos (8/24), al recolocarse la aguja, se obtuvo una RM en el 91.6 por ciento en ambas mitades (22/24), en un nervio no se obtuvo RM en ninguna mitad (2/24)... (TRUNCADO)

Introduction. With a needle apparently in contact with a nerve, tested by US or with the reference of a paresthesia, a MR is not observed during nerve stimulation in a variable percentage of the cases. The object of this study was to experimentally observe the behavior of MR within values + 1mA / 0.1 mseg in different circumstances. Provide scientific evidence to contribute to determine if, with the usual nerve stimulation technique (NS) a nerve can be contacted or penetrated without obtaining before a MR. Material and Methods. Under direct visualization, twelve sciatic nerves from different animals were exposed and stimulated in two imaginary halves. Blinded Observers to the intensity, classified the MR at 1 mA/0.1 mseg, with and without nerve contact and with 0.5 mA in contact. Also, minimum intensity value in contact in which a MR appears and when a MR G2 is obtained was determined, the behavior of the MR with the injection of the LA (local anesthetic), extra-neural and the need to increase or not the intensity to obtain a MR at same intensity. After introducing the needle intraneurally, the intensity was increased until a first MR and a Grade 2 was obtained. Finally, LA was injected intraneurally and the behavior of the RM was observed. Results. RM was obtained with 1 mA in 91.6 per cent of the cases in both halves of the Sciatic nerve without contact, and 100 per cent in contact. With 0.5 mA in 33.3 per cent (8/24) of the cases, MR wasn't observed in one half of the nerve. In one case, MR wasn't obtained in any half. After relocalizing the needle a MR was obtained in 91.6 per cent of the cases in both halves (22/24). The mean minimum intensity in contact for a first MR was of 0.16 + 0.08 mA, and 0.36 + 0.08 mA for a MR Grade 2. An intraneural MR was found in 92 per cent with a mean minimum value of 0.19 + 0.08 mA... (TRUNCADO)

Com uma agulha isolada em aparente contato com o nervo, conforme teste de ultra-som (US) ou presença de parestesia, nao é conseguida resposta motora (RM) a estimulação nervosa em uma porcentagem variável de casos. O objetivo de nossos estudos foi observar o comportamento da RM a valores < 1 mA /0.1 mseg em diferentes circunstancias experimentais. Proporcionar evidencia científica que ajude a determinar se com a técnica usual de estimulação nervosa (NS) é possível contatar ou penetrar um nervo sem antes se obter RM. Material e métodos. Sob visão direta, doze nervos ciáticos de diferentes animais foram expostos e estimulados em duas metades imaginárias. Observadores cegos a intensidade utilizada consignaram a RM obtida com 1 mA/0.1 mseg com e sem contato nervoso, e com 0.5 mA em contato; o valor mínimo de intensidade em contato ao qual aparece uma RM e é obtida uma RM grau 2; o comportamento da RM com injeção anestésica local (AL) extraneural e a necessidade de aumentar ou nao a intensidade para se obter uma RM de igual intensidade. Colocada a agulha intraneural, aumentou-se a intensidade até se obter uma primeira RM e uma RM grau 2. Finalmente, foi injetado o AL intraneural e registrado o comportamento da RM. Resultados. Sem contato nervoso e com 1 mA, obteve-se RM em ambas metades do nervo ciático em 91.6 por cento dos intentos, e com contato neural em 100 por cento. Com 0.5 mA em contato, nao se obteve RM em uma metade em 33.3 por cento dos intentos (8/24); recolocada a agulha, obteve-se RM em 91.6 por cento em ambas metades (22/24), e em um nervo nao foi obtida RM em nenhuma metade (2/24). A intensidade mínima em contato para uma primeira RM foi de 0.14 + 0.07 mA, e de 0.31 + 0.11 mA para uma RM grau 2. Houve RM intraneural em 92 por cento com valor mínimo de 0.19 + 0.08 mA. A RM desapareceu com a injeção de anestésico local; nao foi observado deslocamento do nervo da ponta da agulha. (TRUNCADO)