Analgesic Effects and Neuropathology Changes of Electroacupuncture on Curing a Rat Model of Brachial Plexus Neuralgia Induced by Cobra Venom.

BACKGROUND: Electroacupuncture (EA) is widely applied to treat neuropathic pain. Brachial plexus neuralgia (BPN) is a common form of chronic persistent pain. Few studies have evaluated the analgesic effects and mechanism of EA using the novel animal model of BPN. OBJECTIVE: To observe the curative effects of repeated EA on curing BPN induced by administration of cobra venom to the lower trunk of the right brachial plexus. STUDY DESIGN: Controlled animal study. SETTING: Department of Anesthesiology, Pain Medicine & Critical Care Medicine, Aviation General Hospital of China Medical University. METHODS: Sixty-six adult male Sprague-Dawley rats were equally and randomly divided into the following groups: normal control (NC), brachial plexus neuralgia (BPN), BPN with sham EA stimulation, BPN with EA stimulation starting on postoperative day 1 (EA1), and BPN with EA stimulation starting on postoperative day 12 (EA12). The BPN model was established by administration of cobra venom to the lower trunk of the right brachial plexus. On postoperative day 1 or day 12, EA (constant aquare wave, 2 Hz and 100 Hz alternating frequencies, intensities ranging from 1 - 1.5 - 2 mA) was applied to the right "Shousanli" (LI10) and "Quchi" (LI11) acupoints for 30 minutes, once every other day for 12 times in both groups. Mechanical withdrawal thresholds (MWT) were tested with von Frey filaments. Video recordings were conducted to analyze the spontaneous exploratory behaviors. Moreover, the organizational and structural alterations of the right brachial plexus and cervical cord (C8-T1) were examined via light and electron microscopy. RESULTS: Following the production of the BPN model, the MWT of both ipsilateral and contralateral paws demonstrated a profound decrease (P < 0.05). But after EA interventions, the MWT showed a significant increase (P < 0.05). In comparison to the EA12 group, the analgesic effects of the EA1 group were more significant, and similar results were observed in exploratory behaviors. However, grooming behaviors did not demonstrate significant differences. Meanwhile, on day 12 after surgery it was observed under light microscopy that the inflammatory response in the right brachial plexus and cervical cord (C8-T1) were significantly attenuated after EA stimulation. Furthermore, the demyelination of the brachial plexus and cervical cord (C8-T1) were also reversed. LIMITATIONS: Limitations include the fact that there was demyelination of the cervical cord (C8-T1) in the control group because of inappropriate manipulation. CONCLUSION: Repeated EA contributes significant analgesic effects in the treatment of BPN.

Comparison of two techniques for ultrasound-guided axillary brachial plexus blockade in cats.

Axillary blockade of the brachial plexus (BP) is advocated in humans and dogs for surgical procedures carried out on the foot, carpus and elbow as it provides complete analgesia distally from above the elbow joint. The aim of this study was to develop an ultrasound (US)-guided approach to block the BP in cats. Two groups of 12 feline cadavers each were used to compare two different techniques to block the BP at the axillary level. The reliability of the techniques was assessed by anatomical and computed tomography (CT) studies. Cadavers of the first group were positioned in dorsal recumbency with the forelimb to be blocked adducted (thoracic limbs flexed and orientated caudally) (FAD technique). The second group was positioned in dorsal recumbency with the forelimb abducted 90° (FAB technique). The accuracy of the techniques was determined by US after injecting 1 ml blue ink along the BP nerves, and by CT after injecting 1 ml of an iodinated contrast medium. The anatomical and CT studies confirmed the accuracy of the US location of the BP nerves. Staining of the axillaris, musculocutaneous, radialis, medianus and ulnaris nerves was observed in 100% of cats using the FAB technique and in 66% of the cats using the FAD technique. Rate of complications was higher in the FAD technique. In conclusion, a US-guided axillary approach to the BP by the use of a FAB technique is a safe and feasible procedure to block the BP in the cat. Further studies are needed to ascertain whether the technique can be applied in a clinical setting.

Study of sensory and motor fascicles in brachial plexus and establishment of a digital three-dimensional graphic model.

To investigate a 3-dimensional (3D) model of human brachial plexus including its topography of sensory and motor fascicles with the assistance of the computer technology, 2 brachial plexus were serially horizontally sliced. Each slice was stained by Karnovsky-Roots acetylcholinesterase histochemical method. The stained sections were scanned, and the image was put into the computer serially. At last, the 3D diagram of brachial plexus was made. The internal structure of the brachial plexus was found to be very complicated. The fascicles bifurcated and recombined with one another with no fixed rules. All fascicles were mixed sensory and motor fibers. Acetylcholinesterase histochemical staining from a serial tissue section is a useful technique to distinguish sensory fibers from motor ones. The 3D visualization of the brachial plexus may help to develop a computerized database of the fascicle topography to provide an anatomical reference in fascicular repair of brachial plexus.

Incidence of humeral head of biceps brachii muscle: anatomical insight / Incidencia de la cabeza humeral del músculo bíceps braquial - visión anatómica

Biceps brachii is stated as one of the muscles that shows most frequent anatomical variations. Its most commonly reported anomaly is the presence of an accessory fascicle arising from the humerus which is termed as the humeral head of biceps brachii. Evidence shows a clear racial trend in the incidence of the humeral head of biceps brachii. Therefore, detailed knowledge of this variation in different populations is important for surgical interventions of the arm, nerve compression syndromes and in unexplained pain syndromes in the arm or shoulder region. The goal of this study was to elucidate the incidence and morphological features of this muscle in an adult Sri Lankan population. Upper extremities of the total of one hundred thirty five cadavers were dissected and studied for the presence of accessory heads of the biceps brachii muscle. The proximal and distal attachments of the humeral heads as well as their cranio-caudal, antero-posterior and medio-lateral dimensions were recorded. The incidence of humeral head of biceps brachii was found to be 3.7 percent. In all cases, it was found unilaterally and only in male subjects. The humeral head originated from the antero-medial aspect of the humeral shaft and descended and merged with the other two heads to form a common tendon. The results of the present study further highlight the racial variations in the incidence of humeral head of biceps brachii among Sri Lankans. Knowledge of the occurrence of humeral head of biceps brachii may facilitate preoperative diagnosis as well as the surgical procedures of the upper limb thus avoiding iatrogenic injuries.

El músculo bíceps braquial se conoce como uno de los músculos que muestra las variaciones anatómicas más frecuentes. Su anomalía más común es la presencia de un fascículo accesorio proveniente del húmero, que se denomina cabeza humeral del músculo bíceps braquial. La evidencia muestra una clara tendencia racial en la incidencia de la cabeza humeral del músculo bíceps braquial. El conocimiento acabado de esta variación, en las diferentes poblaciones, es importante para las intervenciones quirúrgicas del brazo, en los síndromes de compresión nerviosa y en los síndromes de dolor inexplicable en la región del brazo o del hombro. El objetivo de este estudio fue determinar la incidencia y las características morfológicas de este músculo en una población adulta de Sri Lanka. Fueron estudiados los miembros superiores en 135 cadáveres, disecados para evaluar la presencia de las cabezas del músculo bíceps braquial accesorio. Fueron registrados el origen e inserción de la cabeza humeral del músculo bíceps braquial, así como su dimensión cráneo-caudal, anteroposterior y mediolateral. La incidencia de la cabeza humeral del músculo bíceps braquial se encontró en el 3,7 por ciento de los miembros estudiados. En todos los casos, su presencia era unilateral y sólo presente en hombres. La cabeza humeral se originó en la región antero-medial de la diáfisis del húmero, descendió y se fusionó con las otras dos cabezas para formar un tendón común. Los resultados de este estudio resaltan aún más las variaciones raciales en la incidencia de la cabeza humeral del músculo bíceps braquial, entre los habitantes de Sri Lanka. El conocimiento de la presencia de la cabeza humeral del músculo bíceps braquial puede facilitar el diagnóstico preoperatorio, así como los procedimientos quirúrgicos del miembro superior, evitando las lesiones iatrogénicas.

Effect of body mass index on the ED50 volume of bupivacaine 0.5% for supraclavicular brachial plexus block.

BACKGROUND: The aim of this study was to determine whether the ED(50) dose of bupivacaine 0.5% for supraclavicular brachial plexus block increases with increasing body mass index (BMI). METHODS: This double-blind, non-randomized trial followed an up-and-down sequential allocation design. Adult patients undergoing elective upper limb surgery under ultrasound-guided supraclavicular brachial block were recruited. A preliminary study was used to guide the dosing schedule for the main study in which patients were divided into three groups according to their BMI (Group A, BMI >27 kg m(-2); Group B, BMI 24-27 kg m(-2); Group C, BMI <24 kg m(-2)). The study design and analysis followed Dixon's small sample model using a 'nominal' sample size of six per group. RESULTS: Twenty-one patients were recruited to the preliminary study. Using isotonic regression, the ED(50) for bupivacaine 0.5% was estimated to be 8.9 ml [95% confidence interval (CI) 7.8-15.9]. In comparison, the ED(50) volume was found to be 10.8 ml (95% CI 5.9-19.7) using the Dixon-Massey formula. In the main study, six patients were recruited in each group with mean (range) BMI of 31.5 (27.2-38.8) kg m(-2) in Group A, 25.6 (24.4-26.3) kg m(-2) in Group B, and 21.6 (19.7-23.8) kg m(-2) in Group C. The ED(50) (95% CI) for Groups A, B, and C were 8.9 (6.2-12.7), 10.7 (7.5-15.4), and 13.4 (9.3-19.1) ml, respectively (P=0.05 for Group A vs Group C). CONCLUSIONS: Our study demonstrates that the ED(50) of bupivacaine 0.5% does not increase with an increase in BMI. We found evidence of a possible inverse relationship between ED(50) and BMI.

Padrones de inervación y localización biométrica de los puntos motores del músculo bíceps braquial en el hombre / Innervation patterns and biometric localization of the motor points of the brachial biceps muscle in man

La inervación del músculo bíceps braquial se torna importante debido a su constitución y a la acción que ejerce a nivel del codo, sobretodo cuando existen lesiones en nervios espinales o médula espinal alta. Con el objetivo de conocer con detalles la disposición de sus nervios y localizar desde el punto de vista biométrico sus puntos motores, se estudiaron 46 miembros superiores de 23 cadáveres formolizados de individuos brasileños, adultos, en los cuales se consideró el número de ramos, longitud, nivel de origen y puntos de penetración en el vientre muscular respecto a una línea trazada entre los epicóndilos humerales (LBE). El nervio musculocutáneo envía un ramo para el músculo en estudio como un ramo común que luego se dividió para sus dos cabezas en 19 casos (41,3%); ramos independientes para cada cabeza se encontraron en las muestras restantes (58,7%). Con respecto al número de ramos, la cabeza larga recibió un ramo (R1) en 35 casos (76,1%), dos ramos (R1 y R2) en 9 casos (19,6%) y tres (R1,R2 y R3) en 2 casos (4,3%); para la cabeza corta se observó un ramo en 39 casos (84,7%), dos en 5 casos (10,9%) y tres en 2 casos (4,3%). Cada uno de los ramos dirigidos a las cabezas del músculo bíceps se dividió en ramos secundarios (RS). Para la cabeza corta, el ramo principal se dividió en 2 RS en 20 casos; en 3 RS en13 casos; en 4 RS en 4 casos, siendo directo sin dividirse en 2 casos. Para la cabeza larga el ramo principal se dividió en 2 RS en 16 casos; en 3 RS en 13; en 4 RS en 3; en 5 RS en un caso y en 6 RS en 1 caso y en una muestra, el ramo principal penetró en el vientre muscular sin dividirse. Los RS penetraron a niveles variables en el vientre muscular. Los resultados obtenidos pueden servir de referencia para procedimientos de punción en los puntos motores o en estudios electromiográficos.

The biceps brachii muscle innervation is important due to its constitution and its function in the elbow joint, mainly when there are in spinal nerves damages or high spinal cord. The purpose of this study was determine with details the nerves disposition of this muscle and locate its motor points. The upper limbs of 23 formolized cadavers of adult Brazilian individuals were studied, in whose it recorded the number of branches, length, origin levels and motor point localization. The localization were recorded using as reference point a line between the humerus epicondyles. The musculocutaneous nerve send a branch for a studied muscle as a common trunk that divides in two branches, each to a different head of the biceps in 19 cases (41.3%); independent branches for each head were observed in the other cases (58.7%). The long head received one branch in 35 cases (76.1%); two branches (B1, B2) in 9 cases (19.6%) and three branches (B1, B2, B3) in 2 cases (4.3%). Each branch divided in secondary branches (SB). In the short head the principal branch divided in two SB in 20 cases; in three SB in 13 cases; in fourth SB in 4 cases and not dividing in 2 cases. In the long head, the principal branch divided in two SB in 16 cases; in three SB in 13 cases; in fourth SB in 3 cases; in five SB in one case and in sixth SB in one case and not dividing in one case. The SB pierce in the muscular belly to different levels. These results can be to use as reference for the puncture procedures in the motor points or in electromyography studies.

Origen y trayecto anómalos del nervio musculocutáneo / Anomalus origin and traject of musculocutaneous nerve

El nervio musculocutáneo se origina del fascículo lateral en el plexo braquial y sus fibras emergen principalmente de las raíces nerviosas anteriores de C5 y C6. Durante la disección de rutina del plexo braquial en un cadáver formolizado, fue encontrada una variación del origen y trayecto de este nervio. El nervio musculocutáneo se originaba de la cara lateral del nervio mediano y después del origen, cruzaba anteriormente al músculo coracobraquial, sin perforarlo, de medial hacia lateral y de proximal hacia distal, para después ramificarse. Las variaciones anatómicas encontradas contribuyen para el estudio de la anatomía y sirven para el cirujano en intervenciones en la fosa axilar y en la parte anterior del brazo, previniendo, así, complicaciones operatorias.

The musculocutaneous is originated from the lateral fascicle in the brachial plexus and its fibers emerge mainly from the anterior nervous roots C5 and C6. During the routine dissection of the brachial plexus in a formolized corpse, its origin variation and passage was found. The nerve was originated on the lateral face of the median nerve and after its origin, crossed anteriorly to the coracobrachial muscle, without perforating it, from medial to lateral, proximal to distal, after to branch off. The anatomical variations found contribute to the anatomy study and they serve as alert for the surgeon in interventions in the axillary's cavity and in the previous store of the arm, preventing, thus, operational complications.

Wartenberg's migrant sensory neuritis.

We describe a patient with the sudden onset of a painful, purely sensory, mononeuritis multiplex. Investigations showed no evidence for any underlying systemic condition. A nerve biopsy showed fascicular wallerian degeneration with perineurial thickening, inflammatory cells, and immunoglobulin G (IgG) deposition. His painful sensory deficits persisted, with no improvement after treatment with prednisone. The clinical characteristics in this case were very similar to those originally described by Wartenberg, and subsequently by other investigators. The investigations in our case strongly suggest that there may be an underlying immune pathogenesis for cases of Wartenberg's migrant sensory neuritis.

Axonal regrowth through a collagen guidance channel bridging spinal cord to the avulsed C6 roots: functional recovery in primates with brachial plexus injury.

Intraspinal implantation of a collagen guidance channel (CGC) to promote axon regeneration was investigated in marmosets with brachial plexus injury. After avulsion of the right C5, C6 and C7 spinal roots, a CGC containing (group B) or not (group A) a nerve segment, or a nerve graft (group C), was ventro-laterally implanted into the cord to bridge the ventral horn and the avulsed C6 roots. No spinal cord dysfunction was observed following surgery. Two months later, the postoperative flaccid paralysis of the lesioned arm improved. In five months, a normal electromyogram of the affected biceps muscle was recorded in all repaired animals. Motor evoked potentials were obtained with a mean amplitude of 13.37 +/- 13.66 microV in group A, 13.21 +/- 5.16 microV in group B and 37.14 +/- 35.16 microV in group C. The force of biceps muscle contraction was 27.33 +/- 20.03 g (group A), 24.33 +/- 17.03 g (group B) and 37.38 +/- 21.70 g (group C). Retrograde tracing by horseradish peroxidase showed labelled motoneurons ipsilaterally located in the C5 and C6 ventral horn, nearby the implantation site. The mean labelled neurons was 32.33 +/- 21.13, 219.33 +/- 176.29 and 64.33 +/- 23.54 in group A, B and C respectively. Histological analysis presented numerous myelinated and unmyelinated regenerating axons in the implant of these animals. Statistical analysis did not show significant difference among the three repaired groups. Our results indicate that spinal neurons can regenerate through a CGC to avulsed nerve roots and induce motor recovery in primates.

[Transmission electron microscope observation of morbid nerve segments in neurocausalgia].

The authors report the observations by TEM of morbid nerve segment from 3 cases of typical neurocausalgia. It was discovered that a lot of collagen fibrils proliferation, myelin sheaths compressed partly or completely disintegrated and exposed axons. A great number of no myelinic nerve fibers, remained and a great number of macrophages were present, which are morphological characteristics of neurocausalgia.

Brachial plexus meningioma, report of a case with immunohistochemical and ultrastructural examination.

Peripheral nerve meningiomas are exceedingly rare neoplasms of controversial origin; only four cases have been reported. Proposed origins of ectopic meningiomas include extradural trapping of arachnoid cells during embryogenesis, ectopic migration of arachnoid cell nests with the developing peripheral nerve, and metaplasia of mature peripheral nerve sheath cells or a common progenitor cell. In this report of a meningioma of the brachial plexus, immunohistochemical and ultrastructural examinations of the tumor matched all the criteria of a traditional meningioma but failed to clarify the origins of such neoplasms.

Hypertrophic brachial plexus neuritis: a pathological study of two cases.

Two patients with brachial plexus neuropathy had recurrent symptoms for years that culminated in the development of a painful lower cervical mass. On macroscopic examination the affected nerves had a fusiform segmental enlargement, suggestive of a nerve sheath tumor, that was excised. Histologically, marked endoneurial edema, florid focal chronic inflammation, extensive onion bulb formation, and perineurial sparing were seen. Electron microscopic studies on one patient revealed microvasculitis; frequent tubuloreticular inclusions in endothelial cells, histiocytes, and lymphocytes; and cylindrical confronting cisternae in lymphocytes. We conclude that some cases of recurrent brachial plexus neuropathy are due to a localized chronic inflammation that may be related to autoimmunity or to a viral infection.