Archive for abril 2012

Plexo Braquial Síndromes compresivos nerviosos asociados a variaciones anatómicas

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AUTOR: Dr. Antonio García-López

Introducción

Aunque las causas más frecuentes de compresión nerviosa son idiopáticas, inflamatorias, postraumáticas o por lesiones ocupantes de espacio existen, además, ciertas variaciones anatómicas que pueden originar o predisponer a síndromes compresivos. Aunque estas causas se mencionan o se explican cuando tratamos cada patología, pensamos que su frecuencia y sus características propias las hacen merecedoras de un capítulo aparte. Su conocimiento es imprescindible por el cirujano de mano ya que su tratamiento consiste, en la mayoría de los casos, en la extirpación de la anomalía anatómica que origina la compresión.

Anomalías que originan síndrome del estrecho torácico

Figura 1
Figura 1

Costilla cervical

La primera descripción se le atribuye al médico y filósofo griego Galeno que vivió durante los siglos II y III. Se trata de una costilla rudimentaria que puede ser unilateral o bilateral y que surge de la séptima vértebra cervical. Su frecuencia oscila entre el 0,004 y el 1% de la población, es tres veces más frecuente en mujeres que en hombres y la afectación es, en la mitad de los casos, bilateral.1 La longitud de la costilla es variable y es muy raro que sea simétrica de forma bilateral. Oscila entre una simple prolongación de la apófisis transversa a una costilla completa que se comporta en todos los aspectos como una costilla torácica. Su importancia radica en que puede originar un cuadro compresivo, fundamentalmente del tronco inferior del plexo braquial y de la arteria subclavia, lo que se denomina síndrome del estrecho torácico (SET), aunque sólo el 10% de los portadores de esta anomalía llegan a tener síntomas (Figura 1).

Los tipos de costilla han sido clasificados en cuatro tipos por Grubert (1869)2. El tipo 1 corresponde a una costilla cervical corta de menos de 2,5 cm. En el tipo 2 la costilla cervical mide más de 2,5 cm, la punta es afilada y continúa con una banda fibrosa. En el tipo 3 la costilla cervical esta fijada a la segunda costilla. Por último, el tipo 4 es una verdadera costilla completa que se acaba articulando con la primer costilla o con el esternón.

Otra causa de SET son las anomalías de la primera costilla. Proceso poco común con una incidencia de 0,34% y con una afectación similar entre ambos sexos. Estas costillas se sitúan más alto de lo normal dando la apariencia de costilla cervical y se insertan por delante en la segunda costilla en lugar del manubrio esternal3.

Clínica

La clínica es superponible a otros cuadros de SET de otra etiología. En los casos sintomáticos se puede observar clínica neurológica bien del plexo braquial superior (C567) o, más frecuente, del inferior (C8T1). En los tipos vasculares se pueden observar signos de isquemia debidos a compresión de los grandes vasos, sensibilidad al frío y fenómeno de Raynoud.

Además de los signos clínicos comentados en el capítulo anterior, la costilla cervical se pone en evidencia en el estudio radiológico simple de la columna cervical, especialmente en las proyecciones oblicuas (Figuras 2a y 2b).

 

 

Figura 2-A Figura 2-B
Figura 2-A Figura 2-B

 

Figura 2.- A) Radiografía anteroposterior cervical donde se observa costilla cervical derecha. B) Proyección oblicua cervical del mismo paciente donde se evidencia con más claridad la costilla cervical rudimentaria.

Tratamiento

La indicación quirúrgica se realiza por la presencia de síntomas neurológicos o vasculares que no mejoran con las medidas conservadoras como antinflamatorios, modificación postural y fisioterapia. Aunque la presencia de una costilla cervical es un dato objetivo, su única presencia no nos da el diagnóstico de síndrome del estrecho torácico. Por otro lado, la presencia de una costilla cervical no mejora los resultados quirúrgicos. Por tanto, el cirujano debe dar poca importancia a la presencia o ausencia de anormalidades óseas para establecer el diagnóstico y sentar la indicación.

 

Figura 3-A Figura 3-B
Figura 3-A Figura 3-B

 

Las técnicas quirúrgicas y los abordajes de esta patología son discutidos en el capítulo del estrecho torácico. Según Sanders (2002) la resección de la costilla cervical exclusivamente tiene más incidencia de recurrencias que la resección de la costilla cervical y de la primera costilla, conjuntamente3. El autor recomienda, en este caso, la vía supraclavicular transversa (Figuras 3a y 3b). La costilla cervical debe ser extirpada completamente hasta la apófisis transversa de C7 (Figuras 3c y 3d). Posteriormente se introduce el dedo por el estrecho torácico y se moviliza el miembro comprobando que el plexo esta completamente liberado. En caso de que persista la compresión se reseca también la primera costilla de forma extraperióstica, en la parte anterior se divide en la unión costocondral y en la parte posterior se puede dejar 1 cm de la apófisis transversa ya que este pequeño fragmento no interfiere con el primer nervio torácico.

 

Figura 3-C Figura 3-D
Figura 3-C Figura 3-D

 

Figura 3.- A) Abordaje supraclavicular transverso, línea de incisión. B) Se comprueba compresión y acodamiento del tronco inferior por la costilla cervical. C) Se rechaza el tronco inferior, en la imagen con cinta clara, para la identificación y liberación de todas las inserciones musculares de la costilla cervical. D) Una vez extirpada la costilla se comprueba completa liberación de la compresión del tronco inferior (cinta clara) y de la arteria subclavia (cinta oscura).

Anomalías musculares

Además de las anormalidades óseas, ciertas anomalías musculares pueden originar un SET. Existen tres espacios donde se puede observar SET: el triángulo interescalénico, el espacio costoclavicular y la región del pectoral menor. En la primera localización, además de la costilla cervical, se han observado anomalias de los músculos escalenos4, omohioideo y esternocleidomastoideo5 que pueden verse implicados en la patogenia de SET. Las anomalías en los músculos escalenos pueden ser en sus inserciones, en su forma o variaciones en número (escaleno mínimus o ligamento transverso-septo-costal)6. El espacio costoclavicular puede estrecharse por variaciones de la primera costilla y de la clavícula.

Figura 4

Figura 4

Figura 4.- Imagen intraoperatoria donde se observa la inserción del tendón de un pectoral menor accesorio en la base y parte superior de la apófisis coracoides. La localización del músculo más profunda origina una compresión del plexo braquial sintomática.

La existencia de un músculo subclavio supernumerario, el subclavius posticus, ha sido atribuida como causa potencial de SET en este espacio7. La región del pectoral menor puede originar el síndrome de hiper-abducción. El autor ha podido observar la existencia de un pectoral menor accesorio con inserciones en la base de la apófisis coracoides y que originaba una impronta en el plexo braquial infraclavicular (Figura 4).

Compresión del nervio mediano

Proceso supracondíleo y ligamento de Struthers

Figura 5
Figura 5.- Dibujos de Bland-Sutton del húmero fetal de los felinos a la izquierda y el foramen supracondilar en los humanos a la derecha.

Robert Knox describió tal estructura en un artículo en el Edinburgh Medical Journal en 18418. El fallecimiento de un jaguar en el circo permitió a Knox dar una lección de anatomía comparativa del foramen supracondíleo en el húmero de los felinos por donde pasa la arteria braquial y el nervio mediano. Esto fue seguido por la observación de un proceso supracondíleo en un cadáver humano, cedido por la Universidad, que correspondía, de forma muy cercana, al foramen visto en el Jaguar8. Sin embargo, ya se había ilustrado esta estructura en la Tabulae arterium de Tiedmann en 18229. La primera descripción de esta estructura rudimentaria se atribuyó erróneamente al zoólogo y anatomista británico John Struthers en 1948, trabajo por el que tomó gran interés Charles Darwin. Por este motivo, esta estructura también lleva el epónimo de ligamento de Struthers10. Según Bland-Sutton (1920) el proceso o espolón supracondíleo es un remanente vestigial embriológico de un músculo propio de los animales mamíferos trepadores, el dorsoepitroclear (Figura 5)11. Se ha visto en algunos reptiles, felinos, lemures, la mayoría de los marsupiales y monos americanos12. El rango de incidencia observada en humanos oscila entre 0,28-2,7%, siendo más común en los europeos13.

Consiste en un espolón óseo que surge del tercio distal, cara anteromedial del húmero y se orienta hacia la articulación del codo. Se asocia a un ligamento (de Struthers) que se extiende desde la punta del proceso óseo hasta el epicóndilo medial formando un foramen por el que discurre el nervio mediano y la arteria braquial o una de sus ramas14. Generalmente se encuentra a 5-7 centímetros por encima del epicóndilo medial.

Clínica
Figura 6
Figura 6.- Radiografia del húmero distal donde se aprecia un pequeño proceso supracondilar.

Generalmente asintomático, aunque puede palparse como una masa en la cara interna del brazo15. Ocasionalmente, puede producir síntomas de compresión del nervio mediano y de claudicación de la arteria braquial, especialmente cuando el codo está en extensión y el antebrazo en pronación15 o en supinación16. La sintomatología neurológica de afectación del nervio cubital es menos frecuente pero también posible. El signo de Tinel puede ser positivo en el sitio de la compresión. La electroneurofisiología puede ser de utilidad para la localización del sitio de compresión. Cuando se sospeche, debe realizarse una radiografía simple del húmero donde se puede localizar el espolón (Figura 6).

Tratamiento

En los casos sintomáticos el tratamiento es la descompresión quirúrgica. Con manguito de isquemia y exanguinación se realiza un abordaje centrado sobre el espolón. Se identifican la arteria braquial y el nervio mediano, distalmente. Se siguen en la parte proximal hasta localizar el ligamento de Struthers y el proceso supracondíleo que se liberan de los tejidos adyacentes. El espolón se reseca lo más cerca posible del hueso y se coloca cera en la superficie ósea expuesta. El ligamento debe también resecarse completamente para evitar recurrencias tras una sección simple. Tras realizar hemostasia se coloca un vendaje blando compresivo.

Músculo de Gantzer

Especial consideración merece la descripción de un músculo anormal en el antebrazo que se denomina músculo de Gantzer. Este músculo está presente en un 45% de la población. Es un vientre muscular accesorio del flexor pollicis longus que se origina en la apófisis coronoides del cúbito (16,6%) o, con más frecuencia, del epicóndilo medial (55,5%) y se dirige hacia el flexor pollicis longus verdadero, pudiendo comprimir el nervio mediano y, en concreto, el nervio interóseo anterior. Este músculo accesorio origina una parálisis aislada del flexor pollicis longus con una actitud de pinza característica17-20.

Variaciones anatómicas de músculos del antebrazo y mano que originan síndrome del túnel carpiano

Por el túnel del carpo discurren 9 tendones flexores (flexor digitorum superficialis, flexor digitorum profundus y flexor pollicis longus) envueltos por una vaina sinovial que rodea el nervio mediano. La existencia de anomalías o variantes de la musculatura intrínseca o extrínseca de la mano en el interior del canal, así como los cambios morfológicos del carpo por los movimientos repetitivos de la muñeca, pueden originar un conflicto de espacio con el nervio mediano y asociar un síndrome del túnel carpiano (STC) dinámico.

Figura 7
Figura 7.- Palmaris longus profundus. El músculo se origina como un tendón delgado de la fascia del flexor digitorum superficialis (FDS). Se inserta dentro del retináculo flexor en su aspecto dorsal.

Las variantes anatómicas de la músculatura flexora del antebrazo son muy frecuentes y pueden producir compresión sintomática del nervio mediano a nivel del canal carpiano o, con menor frecuencia, a nivel del antebrazo. Si la unión distal del vientre muscular a los tendones se encuentra bajo el ligamento anular del carpo puede originar una compresión del nervio mediano. Esto provoca un STC dinámico al producirse un incremento de presión dentro del túnel cuando el vientre muscular se introduce en él. El nervio mediano tiene una estrecha relación con la musculatura flexora del antebrazo, por lo que cualquier vientre muscular accesorio puede incrementar su volumen con el ejercicio o el uso repetitivo y aumentar la presión sobre el nervio mediano a nivel del túnel carpiano o en cualquier punto de su recorrido. Es fácil que con los sobreesfuerzos repetitivos, estas estructuras entren en conflicto con el resto de elementos y originen la sintomatología del STC.

El palmaris longus (PL) es el músculo más variable de la mano y sus anomalías son frecuentes, aunque generalmente no suelen tener repercusiones clínicas. Estas anomalías varían desde un origen invertido (PL reverso)21, digástrico (con una o dos tendones de inserción)22-23, reverso (con tres cabezas)24, vientre accesorio25, inserción bajo el retináculo flexor26, PL profundus (Figura 7)27, hipertrófico (simulando un pseudotumor)28 o un vientre muscular único sin tendón de inserción. Sin embargo, la anomalía más frecuente es su ausencia, sobre todo en mujeres y en el lado izquierdo. En un estudio de 1.600 antebrazos procedentes de cadáver, Reimann y cols. (1996) encontraron una agenesia del PL en el 13% de los casos29. Esta ausencia tiene una gran variabilidad geográfica y se ha descrito en el 63% de la población de la India, 5% en Japón, 2,2% en China y 8% en caucasianos de Norteamérica30-31. Su existencia se ha demostrado relacionada con determinadas patologías de la mano, como lo demuestra el que los pacientes con enfermedad de Dupuytren tengan una presencia estadísticamente significativa mayor de PL32. El palmaris longus profundus puede causar síndrome del tunel carpiano33-34.

Figura 8
Figura 8.- Vientre muscular accesorio del flexor digitorum superficialis del segundo dedo.

Las variantes de los flexores comunes son menos frecuentes y originan menos trastornos clínicos. Se han descrito flexor digitorum superficialis (FDS) accesorios (Figura 8) o con variantes de prácticamente todos los radios de la mano pero, en general, son hallazgos de necropsia y rara vez ocasionan patología35-38.

El origen proximal de los músculos lumbricales se encuentra en relación con la porción distal del túnel carpiano. En condiciones normales, al extender completamente los dedos, la inserción proximal de los lumbricales se encuentra a 10 mm del borde distal del ligamento anular del carpo (LAC). Con la flexión se introducen, en dirección proximal, hasta 30 mm en profundidad (sobre todo el segundo), llegando a ocupar aproximadamente un 80-90% del túnel carpiano (Figura 9). En jóvenes diagnosticados de STC dinámico se ha comprobado que suelen presentar una inserción más proximal de los lumbricales que origina una mayor introducción dentro del túnel carpiano y la compresión del nervio39. La actividad repetitiva que implica flexoextensión digital con agarre y suelta de fuerza origina una hipertrofia de los músculos lumbricales que, al introducirse bajo el LAC, aumentan la presión dentro del túnel carpiano40, así como la desaparición de este efecto cuando se extirpan experimentalmente41.

Figura 9-A
Figura 9-B
Figura 9.- Inserción proximal de los lumbricales. A) Dedos en extensión máxima donde no se aprecian alteraciones ni ocupación del canal. B) Dedos en máxima flexión, donde se aprecia cómo se rellena el canal con los músculos lumbricales, originando un conflico de espacio.

En la serie de Delgado (2005) de 515 casos, las anomalias más observadas fueron: 3 casos de palmaris longus reverso, 4 casos de vientre accesorio del flexor digitorum superficialis y 6 casos de inserción proximal de músculos lumbricales. En su mayoría, se trataba de pacientes jóvenes, con una edad media de 37 años con trabajos de alta demanda funcional o repetitiva, y con una afectación del miembro dominante en el 61% de los casos42. Esto supone un 2,5% de los pacientes intervenidos por STC, cifra similar a otras series publicadas43.

Otras variantes anatómicas descritas que pueden originar un STC con menor frecuencia son: anomalías de inserción del flexor carpi radialis, del flexor carpi ulnaris, pronador cuadratus en forma de músculo radiocarpiano, opponens digiti mínimi, flexor digitorum sublimis y existencia de músculo flexor carpi radialis accesorio o músculo flexor carpis radialis profundus44.

El diagnóstico de estas anomalías es complejo. Un diagnóstico precoz permite evitar gestos innecesarios como la apertura del canal, reintervenciones o un abordaje más amplio. Sin embargo, su diagnóstico suele hacerse en el momento de la cirugía, en la mayoría de los casos. El cirujano encuentra un vientre muscular dentro del canal carpiano que no siempre sabe identificar. El diagnóstico de sospecha es importante en estos casos. En ocasiones, se puede presentar como pseudomasa en la cara volar que origina dolor y parestesias en territorio del nervio mediano con los movimientos del antebrazo. En pacientes jóvenes con síntomas del nervio mediano agudos o unilaterales, relacionados con actividades manuales repetidas, existencia de una pseudomasa en el antebrazo o con recidiva después de un adecuado destechamiento del ligamento anular, se debe considerar la posibilidad de un músculo anómalo. En estos casos la resonancia magnética (RMN) y el registro de potenciales evocados por electromiograma durante la contracción muscular45, permite el diagnóstico del músculo anómalo o la existencia de tumores de estirpe neural que pueden originar cuadros con sintomatología muy similar46.

El tratamiento de estos casos debe consistir en la extirpación del músculo aberrante evitando, si se puede, el destechamiento del ligamento anular del carpo. Es importante la identificación del PL de inserción radial, ya que la apertura de la fascia antebraquial puede originar la compresión del nervio mediano por el tendón y el paciente no mejorará de los síntomas que le llevaron a la cirugía47.

Compresión del nervio cubital

Síndrome cubital en el codo

Varias anormalidades musculares se han atribuido como causa de síndrome del túnel cubital como el músculo ancóneo-epitroclear accesorio48-50 o una cabeza medial del tríceps braquial abultada o chasqueante50,51. También se ha descrito una anormal inserción de la cabeza medial del tríceps en el cóndilo medial52 y el músculo subanconeus, que es una extensión auxiliar de la porción medial del músculo tríceps que se origina del borde medial del olécranon adyacente al tendón del tríceps y se inserta en el aspecto dorsal del epicóndilo medial53. La presencia de anormalidades del tríceps en el canal epitrócleo-olecraniano se ha relacionado con subluxaciones del nervio cubital54,55.

Figura 10
Figura 10.- Abordaje de nervio cubital en el codo donde se observa músculo ancóneo-epitroclear causante de la compresión del nervio. Se identifica el músculo con un mosquito.

Hemos tenido la ocasión de intervenir algún caso de ancóneo-epitroclear sin tendencia subluxante del nervio cubital (Figura 10) que se ha solucionado seccionando el músculo hasta liberación del nervio. La extirpación del músculo aberrante es suficiente para solucionar la compresión. En caso de un nervio con tendencia subluxante se debe realizar una transposición como gesto asociado.

Síndrome del canal de Guyon

Se han descrito varias anomalías anatómicas que pueden originar compresión del nervio cubital en el canal de Guyon. Variaciones a este nivel son raras pero no excepcionales. Se han descrito anomalías de inserción (proximal) del músculo flexor digiti minimi56, el músculo flexor digiti minimi accesorio57. el músculo abductor digiti minimi longus58, el músculo abductor digiti minimi accesorio59, el músculo adductor hipotenar60, el palmaris brevis profundus61, palmaris brevis accesorio62, palmaris longus reverso63 y palmaris longus accesorio64,65. En los cuadros de compresión del nervio cubital, a la altura de la muñeca, se recomienda realizar un estudio de imagen con resonancia magnética nuclear dada la frecuencia de lesiones ocupantes de espacio y anomalias anatómicas que originan esta patología. La RMN nos alertará de la causa de la compresión por la existencia de una variante anatómica muscular. El tratamiento es quirúrgico con extirpación del músculo anormal que origina la compresión.

Compresión del nervio radial

Menos variaciones anatómicas se han relacionado con síndromes compresivos del nervio radial. A nivel proximal del brazo se ha descrito la existencia de un músculo coracobraquial accesorio que se origina en la apófisis coracoides y se inserta en la parte tendinosa del músculo dorsal ancho. El músculo cruza el nervio radial en la axila causando un síndrome compresivo del nervio radial66. Anomalías del músculo tríceps braquial también se han implicado como causa de compresiones del nervio radial. Una cuarta cabeza del tríceps braquial, que se origina en el aspecto proximal posteromedial de la diáfisis humeral distal a la cápsula del hombro. El tendón de esta cuarta cabeza pasa, a lo largo del aspecto medial del húmero, directamente sobre el pedículo neurovascular, cuando entra en el surco espiral del humero pudiendo contribuir en cuadros compresivos del nervio67. También en el codo se ha descrito un músculo braquioradialis accesorio que origina una compresión de la rama superficial del nervio radial a este nivel68. La extirpación de la cuarta cabeza del tríceps en el brazo, o del braquioradialis accesorio en el codo, elimina la compresión nerviosa.

En la muñeca también se ha descrito una variación anatómica del tendón distal del músculo braquiradialis que causa una compresión de la rama sensitiva del nervio radial (síndrome de Wartenberg). Esta variación consiste en un tendón dividido en dos tiras entre las cuales emerge la rama superficial del nervio radial69,70. Esta variación anatómica no es infrecuente, pudiendo tener una incidencia del 3,3% de la población general y ser la causa de un 5% de los síndromes de Wartenberg70. El tratamiento consiste en la resección de la parte dorsal del tendón supernumerario.

Plexo Braquial Transmanubrial Transclavicular Approach in Tumors of the Brachial Plexus.

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Authors: García-López A, Iborra A.

Abstract: The standard transclavicular approach allows only limited and narrow exposure if the cervical thoracic region for the resection of tumors of the brachial plexus is involved. We report 2 cases of retroclavicular tumors of the brachial plexus. We performed a complete resection in both cases using the transmanubrial transclavicular approach. This approach consists of retracting an osteomuscular flap that involves the medial portion of the clavicle, part of the sternal manubrium, the sternoclavicular joint, and the sternocleidomastoid muscle. We describe and discuss this approach, whichprovides access to the entire brachial plexus and the major vessels, thereby affording excellent control of the vessels; it is the approach of choice for tumors in this location.

Key Words: brachial plexus, connective and soft tissue neoplasms, limb
salvage, paralysis, wound closure techniques
(Ann Plast Surg 2011;67: 387–390)

Tumors of the brachial plexus are difficult to remove, as they involve neural or vascular structures and because of their deep location. Retroclavicular tumors are particularly complex because they also involve the neural structures of the brachial plexus itself, the phrenic and vagus nerves (X), the recurrent laryngeal nerve, the supra-aortic arterial trunks and their branches, the brachiocephalic venous trunks, the chest wall, and the thoracic duct on the left side.

They may extend toward the supraclavicular or infraclavicular region, toward the mediastinum, or the axillary region. Tumor resection that spares the limb is the initial objective of our approach to these tumors located in the area of the cervicothoracic transition.

An approach is required that allows us to fully expose the entire plexus with medial extension toward the origin of the subclavian and carotid vessels, the apex, and chest wall, and the possibility to extend to the axilla.

We report 2 cases of tumors of different types and behavior, in similar locations, and discuss their resection using the transclavicular trans-sternal approach. We describe and discuss this approach, which affords suitable exposure and control of the branching of the brachycephalic vein into the external and internal jugular veins, and the subclavian vein, the most proximal section of the subclavian artery, the vertebral artery, and the recurrent laryngeal
nerve.

CASE REPORTS

Case 1

The patient was an 8-year-old boy whose first symptom was pain in the shoulder after swimming. The patient visited another hospital, after a lump was felt in the left supraclavicular fossa; magnetic resonance imaging (MRI) revealed a tumor affecting the left brachial plexus and the subclavian artery and vein. An incisional
biopsy was performed, leading to postoperative partial loss of feeling in the first and second fingers of the hand. The biopsy results revealed aggressive myofibromatosis and the patient visited several surgical departments that ruled out resection; chemotherapy was therefore instated by the oncology department with methotrexate and vinorelbine.

The patient was referred to our brachial plexus surgery unit for evaluation 5 months after diagnosis. Physical examination revealed a 7-cm horizontal supraclavicular lesion parallel to the clavicle, under which was a hard mass that was strongly adhered to the deep layers. The strength of his pectoralis major, biceps brachii, and brachialis muscles was grade 4 on the Medical Research Council scale and grade 5 in the remaining arm muscles. A Tinel’s sign was elicited in the supraclavicular fossa. Arm joints showed full range of motion. Neurophysiologic studies showed upper trunk plexopathy with denervation potentials present in the biceps brachii.

A new MRI scan was performed, which revealed a tumor in the left retroclavicular region, with complete involvement of the entire brachial plexus at the level of the trunks, divisions and fasciculi, and the subclavian artery, which was inside the tumor, and partial involvement of the subclavian vein. The tumor was in direct contact with the first rib and the lung apex, with no apparent infiltration of the ribcage. Definition of the top of the tumor was lost due to the area of postsurgical fibrosis with tumor infiltrate (Figs. 1A–C).The patient underwent surgery under general anesthesia, with a transsternal transclavicular approach. An incision was made through the scar from the previous biopsy and extended medially to the contralateral sternoclavicular joint and laterally to the deltopectoral groove. The subcutaneous tissue and platysma were cut and 2 large flaps were retracted to provide a broad exposure of the sternal manubrium, the clavicle and sternocleidomastoid muscle, and the entire supraclavicular fossa. The sternocleidomastoid muscle was defined before and after its insertion, as it needed to be spared, together with the periosteum covering the clavicle and the sternum. The pectoralis major muscle was disinserted from the medial lower half of the clavicle and from the upper part of the sternum to reveal the costosternal joint, and the sternoclavicular joint capsule wasspared. Osteotomy of the clavicle was performed after removing a small amount of periosteum from the middle third of the clavicle. An inferior dissection was performed at the incisura jugularis using delicate periosteotomes and blunt dissectors, and a malleable retractor was inserted. The space between the costosternal joints of the first and second ribs was identified and another malleable retractor was inserted until it met the other retractor. The purpose of the retractors was to provide protection while performing 2 delicate L-osteotomies using a fine osteotome or a sternotomy saw on the left upper outside angle of the manubrium, including the sternoclavicular

FIGURE 1. Preoperative MRI of case 1. AFIGURE 1. Preoperative MRI of case 1. A, Coronal image showing the tumor located in the supraclavicular and retroclavicular region, extending from the trunks to the fasciculi of the left brachial plexus. B, Coronal angio-MRI showing involvement of the subclavian vessels. C, Sagittal image showing how the tumor completely encompasses the subclavian artery and partially encompasses the subclavian vein.

Intraoperative photographs of case 1FIGURE 2. Intraoperative photographs of case 1. A, Retraction of the osteomuscular flap with the upper angle of the sternum,
the sternoclavicular joint and the medial half of the clavicle over the sternocleidomastoid muscle, and exposure of the tumor.
B, Intraoperative picture after total resection of the tumor. The image shows the complete liberation of the entire brachial
plexus and the subclavian artery and vein. The iatrogenic lesion of the anterior division of the upper trunk with no severe
functional repercussions can be seen. The osteomuscular flap can be seen in the upper left of the image. C, Intraoperative
photograph after repair of the anterior division of the upper trunk with six 2.5-cm long sural nerve grafts.

joint and the costosternal joint of the first rib, while sparing the entire insertion of the sternocleidomastoid muscle in the clavicle and in the sternum. The costosternal cartilage of the first rib attached to the sternum was cut using a scalpel. The medial half of the clavicle and the left upper outside angle of the sternum were elevated toward the cranium, joined by the sternoclavicular joint on the sternocleidomastoid muscle. The entire osteomuscular flap was wrapped in a damp pad. The sternohyoid muscle and subclavian muscle were exposed. Cutting these muscles made it possible to expose the entire tumor completely surrounding the brachial plexus, from the trunks to the fasciculi. The subclavian artery encompassed completely by the tumor and the subclavian vein partially. The vessels and nerves above and below the tumor were identified. The subclavian artery and vein were first completely freed; this operation required an intratumor access route. All the nerves of the plexus were dissected to reveal a postbiopsy iatrogenic section of the anterior division of the upper trunk, and the tumor was resected completely (Figs. 2A, B). Intraoperative electrostimulation was used in locating the damaged nerve. The lesion was repaired with 6 sural nerve grafts of 2.5-cm taken from the right leg; the grafts were sutured using fibrin glue (Fig. 2C). The sternum was closed using reabsorbable bone sutures and the osteosynthesis of the clavicle was performed using a minifragment titanium plate. The patient’s clinical course revealed that feeling was regained in the first 2 fingers, together with clavicular pseudarthrosis was observed, which required further surgery to perform an iliac-crest bone graft and repeat osteosynthesis;
the osteosynthesis was consolidated and the patient regained function of the limb with no differences compared with the contralateral limb. The 3-year follow-up revealed no symptoms or radiographic signs of tumor recurrence. Medical Research Council grading system graded 5 power in all arm muscles. All arm joints maintained full range of motion.

Microscopic and pathologic examination revealed neoplastic proliferation consisting of fusiform cells with a large cytoplasm, and a large nucleus with a clearly visible nucleolus. Many inflammatory cells were observed between these cells, together with focal presence of osteoclast-like giant cells. The lesion extended to the margin of the resection. Immune staining was positive for vimentin externally and focally positive for ALK-1 and actin. Necrosis foci were observed. Mitosis was rare. Twenty percent of the tumor cells stained positive with Ki-67. The histopathology diagnosis was an inflammatory myofibroblastic tumor (IMT).

Case 2

A 16-year-old boy visited his doctor because of a growth in the left subclavicular region. The patient experienced no pain or neurologic deficiency. He was referred to the thoracic surgery department where an MRI scan of the region was performed; the scan revealed a subclavicular tumor in close contact with the brachial plexus, and the patient was therefore referred to our unit.

FIGURE 3. Preoperative MRI of case 2. A, Axial image showing the tumor located in the retroclavicular and subclavicular region,
extending between the divisions and fasciculi of the left brachial plexus. B, Axial image in another MRI sequence showing
compression of the subclavian vessels and the brachial plexus. C, Coronal image showing how the tumor encompasses
the fasciculi of the brachial plexus.

FIGURE 4. Intraoperative photographs of case 2. A, Transsternal transclavicular approach that allowed for resection of the tumor. The photograph shows the broad exposure of the subclavian vessels from the mediastinum to the axilla and exposure of the entire brachial plexus. B, Photograph of the resected part marked with stitches. C, Intraoperative picture of the reconstruction of the approach, with cerclage wire in the sternum and a DCP in the clavicle.

Tests revealed a tumor measuring 10 x 7.5 cm, which appeared to originate in the pectoralis minor and extend to the retroclaviculararea, from the sternoclavicular joint to the axilla. The upper lateral end of the lesion met with the coracoid apophysis of the scapula and with the deltoid muscle. The tumor was compressing the subclavian vessels, but these were still patent. The brachial plexus was being pushed toward the posterior side, with no visible infiltration, although it was in close contact with the tumor (Figs. 3A–C). An ultrasound-guided percutaneous biopsy was performed in the region of the axilla and revealed low-grade mesenchymal infiltration suggestive of fibromatosis. The patient underwent surgery under general anesthesia, with a transmanubrial transclavicular approach identical to that of the first patient, with osteotomy of the upper quadrant of the sternum and osteotomy of the clavicle. The subclavian vessels and brachial plexus were identified after dissecting and separating the tumor, and no infiltration was observed (Fig. 4A). We performed a subtotal extirpation of the pectoralis major and total of the pectoralis minor; these muscles were infiltrated and the tumor was not exposed at any time. The tumor had also infiltrated the tip of the coracoid apophysis, which therefore required resection at its base (Fig. 4B). Reconstruction of the sternum was performed using cerclage wire and osteosynthesis of the clavicle was performed using a 6-hole dynamic compression plate (Fig. 4C). The results of the anatomic pathology study revealed musculoaponeurotic fibromatosis in contact with the surgical margin at 1 point. The oncology department decided to instate adjuvant radiation therapy in the postoperative period. The postoperative clinical course was satisfactory and the patient experienced no limitations of shoulder movement or neurologic deficiency in the limb. Radiologic examinations in the follow-up period revealed consolidation of the clavicle, which was determined by means of a computed tomography scan a year after the operation. Follow-up clinical and imaging examinations revealed no recurrence 2 years after the resection.

DISCUSSION

IMTs and desmoid tumors are true benign solid tumors; they are rare and affect children and young adults. Although these tumors are histopathologically benign, they cannot be differentiated from malignant tumors due to their local invasiveness and their tendency to recur.1 The location of the IMT in the peripheral nerves is exceptional,2–4 and we have found no reported cases in the brachial plexus. In some cases, IMT may become malignant.5–7 According to the literature, presentation of desmoid tumors in the brachial plexus is not so exceptional.8–9 The only treatment that has been shown to be effective in managing these tumors is total surgical resection in both primary and recurring tumors. In most cases, other measures such as chemotherapy and radiation therapy should be avoided, as they are ineffective and aggressive for a tumor with limited biologic potential.

However, there is a considerable incidence of postoperative recurrence, ranging from 8% to 37%.8–13 Tumor locations that make resection difficult, as in our cases in the brachial plexus, make treatment difficult. Resection of the tumor is associated with a considerable risk to the structures involved or encompassed by the tumor and alternative treatment, such as chemotherapy and radiation therapy, are ineffective on their own and are only used as adjuvant therapy.8 –9,11 Radiation therapy causes fibrosis and makes resection considerably more complicated, particularly in cases of recurrence.

The inability to resect a slow-growing tumor in a young person or child is a dramatic situation that causes anxiety in the patients and their family members. As occurred, in these cases, these are patients who have already experienced multiple visits to doctors and different surgical departments, where they were initially told that the tumor could not be resected.

The decision to operate was taken, although resection of lesions in this location requires experienced surgical teams.The supraclavicular approach frequently used to examine the trunks of the brachial plexus or decompressions in thoracic outlet syndrome does not allow for examination of the retroclavicular plexus. The standard transclavicular approach of Fiolle and Delmas (1921) is usually carried out to examine and repair the brachial plexus in cases of traumatic injury. This approach affords broad access to the entire brachial plexus, but only provides limited access to the more medial and mediastinal structures (lower trunk and divisions), and it does not provide complete exposure of the vascular structures, especially in the more medial part.

In tumors of the brachial plexus that involve the large vessels and the lower trunk and divisions, a more extensive approach such as the transmanubrial transclavicular approach is preferable. The description of this approach has been attributed to Sundaresan, but he resected the bone segment and therefore killed part of the sternal manubrium and the medial portion of the clavicle, which he used as grafts in tumors of the second to fourth dorsal vertebrae.14 However,
the first description of this approach based on the retraction of an osteomuscular flap that allows for reconstruction and spares the sternocostal joint was reported by Bonney in 1976.15 Although a large amount of bone is retracted, vascularization is maintained via the insertion of the sternocleidomastoid muscle. However, it was Birch who published the only series of 17 cases in different applications (spinal tumors, cervicothoracic scoliosis, soft-tissue tumors, T2-T3 disc hernias, osteomyelitis of the first rib, and neuritis of the brachial plexus) and publicized its use in tumors of the brachial plexus.16,17 This approach is technically highly demanding and requires experience in vascular surgery and neurosurgery, and considerableknowledge of the anatomy of the area; however, it does afford excellent exposure of all the structures and control of the proximal great vessels. The complications in the Birch series included pneumothorax in 30% of cases and pseudarthrosis of the clavicle in 23% of cases, although 3 patients died in the follow-up period. We observed pseudarthrosis in the younger patient, in whom we used a mini-fragment titanium plate that broke after a year.

Webelieve that this complication can be minimized by using modern preformed compression plates and locking screws, and by sparing the periosteum connected to the sternocleidomastoid muscle, as performed in the second case. No cases of sternal pseudarthrosis
were observed in the Birch series or in our patients.16,17

We believe that it is an appropriate approach for resecting tumors of the brachial plexus provides broader exposure and allows for decompression and direct viewing of the entire plexus and vascular structures. The approach also allows for suitable reconstruction, with only a moderate risk of clavicular pseudarthrosis.
Familiarity with the anatomy of the area and a careful dissection technique ensure adequate access with the minimum amount of complications.

REFERENCES

  1. Fisher C. Miofibroblastic malignancies. Adv Anat Pathol. 2004;11:190 –201.
  2. Beer T, Carr NJ, Weller RO. Inflammatory pseudotumor of peripheral nerve.Am J Surg Pathol. 1998;22:1035–1036.
  3. Perez-Lo´pez C, Gutierrez M, Isla A. Inflammatory pseudotumor of the median nerve. Case report and review of the literature. J Neurosurg. 2001; 95:124 –128.
  4. Weiland TJ, Scheithauer BW, Rock MG, et al. Inflammatory pseudotumor of nerve. Am J Surg Pathol. 1996;20:1212–1218.
  5. Dishop MK, Warner BW, Dehner LP, et al. Successful treatment of inflammatory myofibroblastic tumor with malignant transformation by surgical resection and chemotherapy. J Pediatr Oncol. 2003;25:153–158.
  6. Donner LR, Tompler RA, White RR. Progression of inflammatory myofibroblastic tumor (inflammatory pseudotumor) of soft tissue into sarcoma after several recurrences. Hum Pathol. 1996;27:1095–1098.
  7. Hedlund GL, Navoi JF, Galliani CA. Aggressive manifestations of inflammatory pulmonary pseudotumor in children. Pediatr Radiol. 1999;29:112–116.
  8. Goubier JN, Teboul F, Oberlin C. Desmoid tumors brachial plexus. Chir Main. 2003;22(4):203–206.
  9. Seinfeld J, Kleinschmidt-DeMasters BK, Tayal S, et al. Desmoid-type fibromatosis involving the brachial plexus. Neurosurg Focus. 2007;15:22:E22.
  10. Cofin CM, Watterson J, Priest JR, et al. Extrapulmonary inflammatory myofibroblastic tumor (Inflammatory pseudotumor). A clinicopathologic and immunohistochemical study of 84 cases. Am J Surg Pathol. 1995;19:859–872.
  11. Kovach SJ, Fischer AC, Katzman PJ, et al. Inflammatory myofibroblastic tumors [review]. J Surg Oncol. 2006;94:385–391.
  12. Meis JM, Enzinger FM. Inflammatory fibrosarcoma of the mesentery and retroperitoneum. A tumor closely simulating inflammatory pseudotumor. Am J Surg Pathol. 1991;15:1146 –1156.
  13. Souid AK, Ziemba MC, Dubansky AS, et al. Inflammatory myofibroblastic tumor in children. Cancer. 1993;72:2042–2048.
  14. Sundaresan N, Shah J, Foley KM, et al. An anterior surgical approach to the upper thoracic vertebrae. J Neurosurg. 1984;61:686–690.
  15. Bonney G. Watson-Jones Lecture, 1976. Some lesions of the brachial plexus. Ann R Coll Surg Eng. 1977;59:298 –306.
  16. Birch R, Bonney G, Marshall RW. A surgical approach to the cervicothoracic spine. J Bone Joint Surg. 1990;72B:904 –907.
  17. Birch R, Bonney G, Wynn Parry CB. Surgical disorders of the peripheral nerves. Edinburgh, United Kingdom: Churchill Livingstone; 1998.

Plexo Braquial Transfer of the Nerve to the Brachioradialis Muscle to the Anterior Interosseous Nerve for Treatment for Lower Brachial Plexus Lesions: Case Report

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AUTHORS:  Antonio García-López, MD, Pablo Sebastian, MD, Francisco Martinez, PhD, David Perea, MD

In lower lesions of the brachial plexus (C8–T1) there is good function of the shoulder, elbow, and wrist, although that of the hand is impaired. Reconstruction of finger flexion is generally obtained by tendon transfer. We present a case report involving transfer of the motor nerve branch of the brachioradialis muscle to the anterior interosseous nerve to restore finger flexion in acute lower brachial plexus lesion. (J Hand Surg 2011;36A:394397. Copyright © 2011 by the American Society for Surgery of the Hand. All rights reserved.)

Key words Brachial plexus, nerve injury, nerve transfer, neurotization, paralysis.

ISOLATED LESIONS OF the lower 2 roots (C8–D1) of the brachial plexus, known as Dejerine-Klumpke, are uncommon lesions and account for 3% of the supraclavicular lesions of the brachial plexus.1 The usual mechanism is traction of the abducted arm, caus­ing tearing of the lower roots. This leads to a functional motor loss that is essentially equivalent to a high me­dian and ulnar nerve paralysis and sensory loss in the territory of the ulnar nerve.

In adults, attempts to restore flexion of the fingers by nerve repair at the plexus level have always been un­successful. Therefore, tendon transfers, tenodesis, and trapeziometacarpal arthrodesis have been done to ob­tain partly effective “automatic” thumb opposition, sim­ilar to that of a tetraplegic hand.2 When no muscle was available, the alternative was transfer of a functional, free gracilis muscle.3,4 Recently, selective nerve trans­fer to the posterior groups of the median nerve of the arm have been performed, using the phrenic nerve in complete lesions5,6 and using the brachialis branch of the musculocutaneous nerve7 with satisfactory results.

From the Upper Limb Unit, Orthopaedic Department, Hospital General Universitario de Alicante,Spain.

Received for publication August 19, 2010; accepted in revised form November 19, 2010.

No benefits in any form have been received or will be received related directly or indirectly to the subject of this article.

Corresponding author: Antonio García-López, MD, Hospital General Universitario de Alicante, Orthopaedic Department, C/ Madre Teresa de Calcuta, 4 B4 E2 4I, Alicante 03016, Spain; e-mail: garcialopez1@hotmail.com.

0363-5023/11/36A03-0003$36.00/0 doi:10.1016/j.jhsa.2010.11.030

The posterior fascicular group (PFG) of the brachial median nerve is composed mainly of the branches to the anterior interosseous nerve and to the palmaris longus, as well as some fine branches to the proximal part of the flexor digitorum superficialis or flexor digitorum pro­fundus.

In an attempt to obtain the maximum number of axons for transference and maximum synergistic effect, and to be as near as possible to the muscles affected, we propose a new technique that involves transferring the brachioradialis muscle branch (BRMB) directly to the anterior interosseous antebrachii nerve (AIN). We pres­ent a detailed description of this technique.

CASE REPORT

A 52-year-old man had injured his left arm in a motor­cycle accident. He was seen by us as an outpatient 4 months after the accident, complaining that he could not move his hand, although there was no problem with movement of his shoulder, elbow, or wrist.

Tinel’s sign was negative for paresthesias in the supraclavicular area. Sensory function was good in the 3 radial digits, but there was anesthesia of the ring and little fingers. There was no Horner’s syndrome and no neuropathic pain. The shoulder, biceps brachii, and triceps had a normal muscle power of M5. The remain­der of motor function was as follows: pronator teres (PT), M5; supinator, M5; brachioradialis, M5; extensor carpi radialis longus and brevis, M4; extensor carpi ulnaris, M5; flexor carpi radialis, M4; and flexor carpi ulnaris, M1. There was neither extension/flexion, ab­duction, or opposition of the thumb (M0). Extension of the index through small fingers was M3. Finger flexion was absent. There was paralysis of the intrinsic muscles of the hand. Magnetic resonance imaging showed left side meningoceles at C8 and T1 levels. Electrophysi­ologic studies were consistent with preganglionic le­sions of the brachial plexus of the roots of C8 and T1. No motor unit potentials were seen in the muscles innervated by the C8 and T1 nerve roots. Nerve con­duction studies showed the presence of sensory action potentials in the C8–T1 territory.

Surgical treatment was performed 5 months after the initial injury. The dissections were carried out under general anesthesia without pharmacologic paralysis, with a pneumatic tourniquet and 4X magnifications. We used a zigzag incision, anterior to the elbow.

The radial nerve was explored as it entered the in­terstitial canal between the biceps brachii and brachio­radialis muscles. In the superior portion of the canal we identified and stimulated the BRMB. As in 33% of the Caucasian population, the motor branch from radial nerve to the biceps brachii was not present8,9 in this patient. Distally, we found the following radial nerve branches: the extensor carpi radialis longus muscle branch and extensor carpi radialis brevis muscle branch, for the supinator, the posterior interosseous nerve and its superficial sensory branch (Fig. 1).

The median nerve was identified in the depths of the internal bicipital canal, along with the vascular bundle. Dissection of the median nerve extended proximally to the junction of the lower and middle thirds of the arm and distally between the 2 heads of the PT muscle, as far as the starting point of the AIN and its entrance into the arch of origin of flexor digitorum superficialis mus­cle. The AIN originates in the dorsoradial aspect of the median nerve and gives off branches to innervate the flexor pollicis longus (FPL), flexor digitorum profundus (FDP)—particularly to the index, middle, and occasion­ally ring fingers—and further distally, the pronator cuadratus. After the origin of the anterior interosseous nerve, we observed the origin of the muscle branch to the flexor digitorum superficialis. More proximally, from the anterior part of the median nerve, the muscle branches for the PT and the flexor carpi radialis were seen, and in this patient, an absence of the palmaris longus muscle and nerve was observed (Fig. 2). Intra­operative electrostimulation is useful in locating these nerves.

Figure 1

FIGURE 1: Identification of the radial nerve at the bottom of the external bicipital canal. Distal on the top. In the left part, the cutaneous antebrachii lateralis nerve and the basilic vein, displaced laterally with a retractor, can be seen. The radial nerve is shown pulled to the right with a rubber band before dividing into its superficial and deep branches. Likewise, the extensor carpi radialis longus muscle branch is shown with a black arrow and the BRMB with a white arrow, which is the one to be used for transference.

The AIN was mobilized proximally by interfascicu-lar dissection and can easily reach the distal third of the upper arm in the posterior part of the median nerve, 1 cm proximal to the origin of the BRMB (Fig. 3). We cut the fascicle of the median nerve corresponding to the AIN with a 1.5 mm neurotome. With the 1.5 mm neurotome, we also cut the BRMB near its entry into the muscle and transferred it to the AIN. Nerve coap­tation without tension was obtained with 9-0 epineural sutures and Tissucol (Baxter AG, Viena, Austria) using a microscope (Fig. 4). During the postoperative period, the arm was immobilized with the elbow in flexion­supination for 6 weeks to prevent muscle contraction or flexion/extension of the elbow, which could cause a suture dehiscence.

At the 3-month follow-up visit, the limb had recov­ered to the preoperative status, with no functional deficit of flexion of the elbow or of supination, following transference of the BRMB. At 5 months after surgery, the patient began to recover flexion of his fingers, and after a year, there was flexion of M3 for the FPL, M2 for the FDP of index and middle fingers, and M1 for the FDP of the ring and small fingers.

TRANSFER OF THE NERVE TO THE BR MUSCLE TO THE AIN

Figure 2 Figure 3
FIGURE 2: An intraoperative photograph of dissection of the median nerve. Distal on the top. To the right there is the PT muscle branch, marked with a black arrow. The AIN is marked with a white arrow. The origin of the flexor digitorum superficialis muscle branch (no marker) can then be seen crossing the AIN toward the flexor digitorum superficialis muscle. FIGURE 3: Proximal interfascicular intraneural dissection of AIN, labeled with a black arrow.

DISCUSSION

In lesions of the lower brachial plexus that involve the last 2 roots (C8, T1), some of the functions of the median nerve are affected. Sensory function is main­tained, and involvement is mainly of the motor function of the PFG and the medial fascicular group of the median nerve, with preservation of the function of the anterior fascicular group (AFG). The AFG is mainly motor, and it innervates the PT and flexor carpi radialis muscles, which still function in lesions of the inferior trunk. The medial fascicular group carries all the sen­sory fibres to the hand and retains this function, but it also contains some motor fascicles of flexor digitorum superficialis and the motor fibers to the hand in which the muscles are paralyzed. The PFG is also mainly motor and carries fibers of the AIN, which innervate the

FDP of the thumb, index, and middle fingers, FPL, and pronator cuadratus.5 The priority in paralysis of the lower 2 roots is to recover flexion of the digits so that the PFG should serve as the recipient for nerve transfer.

The brachioradialis is an accessory muscle for flex­ion of the elbow and an accessory supinator when the arm is maximally pronated. Because it does not play an important part in flexing the elbow, its denervation does not cause functional impairment of this movement.

Figure 4

FIGURE4: Intraoperative photograph showing the coaptation of the BRMB transferred to the AIN. The completed nerve repair rests on the rubber background.

Accioli10 described a technique of nerve transfer of the epitrochlear branch or AFG of the median nerve by direct coaptation with the branch to the brachialis mus­cle.10 However, this technique is useful only in cases involving C7, C8, and T1 roots in which wrist flexion is impaired. More function is established in the hand by restoring flexion of the digits because the goal is to re-establish digital pinch. In some cases in which Ac­cioli’s technique was used, good results were reported in PT muscle function but weakness in FPL muscle activity.11 Gu7 suggested a more functional transfer of the branch to the brachialis muscle for the median nerve.7 After a careful anatomical study, he located in the internal aspect of the arm the nonfunctioning fasci­cles of the flexors of the fingers in the posterior quarter of the median nerve, by dissecting between fascicles and logically giving priority to the neurotization of PFG rather than AFG. Although neurophysiological studies using sensory evoked potential help locate the PFG, the limitation that one does not observe anatomical conti­nuity of the neurotized fascicles with the AIN leaves room for error in the transference. However, Gu’s re­sults were slightly worse than those from our case (M2 for FPL and FDP of index and middle fingers). Nerve transfer of the AIN can be performed more distal than the techniques previously proposed, and therefore, closer to the target muscles, which facilitates rapid reinnervation and better recovery. The site of AIN is more distal, and an intraneural proximal extension is done of the PFG of the median nerve to obtain direct neurorrhaphy with the BRMB. Therefore, it is not sub­ject to location errors, and intraoperative sensory evoked potential studies are unnecessary. The proce­dure, as shown by our clinical experience, is done using a single incision on the anterior aspect of the elbow, is simple, is technically possible to reproduce, and permits recovery of flexion of the first 3 radial digits. The results are obviously more moderate than the nerve transfers that have been made in isolated lesions of the median nerve. This is due to antagonistic mus­cles completely retaining their function.12

This technique is indicated for recovery of flexion of the thumb and fingers in recent lower brachial plexus lesions (C8–T1) without reducing flexor function of the wrist or elbow. This technique could also be applicable in the flexor phase of group 3 to 7 quadriplegia.

REFERENCES

1. Midha R. Epidemiology of brachial plexus injuries in a multitrauma population. Neurosurg 1997;40:1182–1189.

2. Gohritz A, Fridén J, Herold C, Aust M, Spies M, Vogt PM. Tendon transposition to restore muscle function in the hand [in German]. Unfallchirurg 2007;110:759–76.

3. Manktelow RT, Mckee NH. Free muscle transplantation to provide active finger flexion. J Hand Surg 1978;3:416 –421.

4. Doi K, Sakai K, Kuwata N, Ihara K, Kawai S. Reconstruction of finger and elbow function after complete avulsion of the brachial plexus. J Hand Surg 1991;16A:796 –803.

5. Zhao X, Lao J, Hung L-K, Zhang G-M, Zhang L-Y, Gu Y-D. Selective neurotization of the median nerve in the arm to treat brachial plexus palsy. An anatomic study and case report. J Bone Joint Surg 2004;86A:736–742.

6. Zhao X, Lao J, Hung LK, Zhang GM, Zhang LY, Gu YD. Selective neurotization of the median nerve in the arm to treat brachial plexus palsy. J Bone Joint Surg 2005;87A Suppl 1, Part 1:122–135.

7. Gu Y-D, Wang H, Zhang LY, Zhang GM, Zhao X, Chen L. Transfer of brachialis branch of musculocutaneous nerve for finger flexion: anatomic study and case report. Microsurgery 2004;24:358–362.

8. Blackburn SC, Wood CP, Evans DJ, Watt DJ. Radial nerve contri­bution to brachialis in the UK Caucasian population: position is predictable based on surface landmarks. Clin Anat 2007;20:64 –67.

9. Frazer EA, Hobson M, McDonald SW. The distribution of the radial and musculocutaneous nerves in the brachialis muscle. Clin Anat 2007;20:785–789.

10. Accioli De Vasconcellos ZA, Mira JC. Contribution a l’étude des neurotisations intra-et extra-plexuelles du plexus brachial et de ses branches terminales. Étude chez le Rat et chez l’Homme. [Contri­bution to intra and extra brachial plexus and terminal branches neurotisations. Animal and human study]. Thèse. Université de Paris 05, Paris. 1999.

11. Palazzi S, Palazzi JL, Caceres J-P. Neurotization with the brachialis muscle motor nerve. Microsurgery 2006;26:330–333.

12. Hsiao EC, Fox IK, Tung TH, Mackinnon SE. Motor nerve transfers to restore extrinsic median nerve function: case report. Hand 2009; 4:92–97. Epub 2008 Sep 19.

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