Compressive Structures of the Median Nerve at the Elbow / Estructuras Compresivas del Nervio Mediano en el Codo

SUMMARY: The objective of this study was to analyze the potential for compression of the median nerve (MN) caused by the bicipital aponeurosis (BA), the humeral and ulnar heads of the pronator teres muscle (PTM) and the arcade of the flexor digitorum superficialis muscle (FDS) in recently deceased cadavers. In this analysis 20 forearms of 10 recently deceased adult male cadavers were dissected. Dissections were performed in the institution's autopsy room or anatomy laboratory. The short and long heads of the biceps brachii muscle, as well as the BA were identified in all upper upper limbs. The BA received contribution from the short and long heads of the biceps brachii muscle. In 12 upper limbs the BA was wide and thickened and in 8 it was supported by the MN. In 5 upper limbs, the BA was wide but not very thick, and in 3 it was narrow and not very thick. We identified the existence of the FDS muscle arcade in all dissected upper limbs. A fibrous arcade was identified in 4 forearms, a muscular arcade in 14 and a transparent arcade in 2 upper limbs. In all of them, we recorded that the arcade was in contact with the MN. We recorded the humeral and ulnar heads of the PTM in all dissected upper limbs, with the presence of fibrous beams between them along their entire length. The MN was positioned between the humeral and ulnar heads of the PTM in all upper limbs. In eight upper limbs (40 %), we identified that the BA had thickness and contact with the MN with the potential to cause its compression. Compression between the humeral and ulnar heads of the PTM by the fibrous connections has the potential to cause nerve compression in all upper limbs (100 %). We did not identify that the anatomical structure of the FDS arcade had the potential to cause compression in the MN.

El objetivo de este estudio fue analizar la potencial compresión del nervio mediano (NM) causado por la aponeurosis bicipital (AB), las cabezas humeral y cubital del músculo pronador redondo (MPR) y la arcada del músculo flexor superficial de los dedos (MFS). En este análisis se diseccionaron 20 antebrazos de 10 cadáveres masculinos de individuos adultos fallecidos recientemente. Las disecciones se realizaron en la sala de autopsias o en el laboratorio de anatomía de la Institución. En todos los miembros superiores se identificaron las cabezas corta y larga del músculo bíceps braquial, así como la AB. La AB recibió contribución de las cabezas corta y larga del músculo bíceps braquial. En 12 miembros superiores la AB era ancha y engrosada y en 8 estaba sostenida por el NM. En 5 miembros superiores la AB era ancha pero poco gruesa, y en 3 era estrecha y de menor grosor. Identificamos la existencia de la arcada muscular MFS en todos los miembros superiores disecados. Se identificó una arcada fibrosa en 4 antebrazos, una arcada muscular en 14 y una arcada delgada y transparente en 2 miembros superiores. En todos ellos registramos que la arcada estaba en contacto con el NM. Registramos las cabezas humeral y cubital del MPR en todos los miembros superiores disecados, con presencia de haces fibrosos entre ellas en toda su longitud. El NM estaba situado entre las cabezas humeral y cubital del MPR en todos los miembros superiores. En ocho miembros superiores (40 %), identificamos que la AB era gruesa y tenía contacto con el NM con potencial para causar su compresión. La compresión entre las cabezas humeral y ulnar del MPR, por las conexiones fibrosas, tiene el potencial de causar compresión nerviosa en todos los miembros superiores (100 %). No identificamos que la estructura anatómica de la arcada MFS tuviera el potencial de causar compresión del NM.

Efecto del ácido láctico en la respuesta celular del sistema inmunitario durante la fase inflamatoria temprana en el nervio isquiático dañado por compresión / Effect of lactic acid on the cellular response of the immune system during the early inflammatory phase in the sciatic nerve damaged by compression

En órganos dañados, el ácido láctico (AL) modifica la respuesta inmune innata e inflamatoria, induciendo una menor expresión de citoquinas pro-inflamatorias, que provocan, la modulación del reclutamiento de células inmunes. El daño por compresión del nervio isquiático (NI) desencadena una respuesta inflamatoria y un aumento exponencial del infiltrado inflamatorio de células inmunes, produciendo la destrucción de axones y pérdida funcional del nervio. El objetivo de este estudio es evaluar el efecto agudo de la inyección de AL, sobre la proporción de células inmunes en la fase inflamatoria temprana, en el sitio de lesión del NI post compresión. Para ello, se utilizaron 15 ratas machos Sprague Dawley adultas, en tres grupos de compresión nerviosa. Un grupo control, un grupo control negativo con placebo (100 µL PBS) y un grupo experimental con inyección de 100 µL de AL [20mM]. Al tercer día los NI se analizaron histológicamente y se estableció la proporción de células inmunes en el sitio de lesión. Los resultados muestran que la inyección intraneural de AL provoca una disminución en el porcentaje de linfocitos y un aumento en el porcentaje de macrófagos. Este es el primer trabajo de inyección intraneural de AL y demuestra el efecto modulador del AL sobre las células inmunes en el sistema nervioso periférico.

In damaged organs, lactic acid (LA) modifies the innate and inflammatory immune response, inducing a lower expression of pro-inflammatory cytokines, which provoke the modulation of immune cell recruitment. Damage by compression of the sciatic nerve (SN) triggers an inflammatory response and an exponential increase in the inflammatory infiltrate of immune cells, producing the destruction of axons and functional loss of the nerve. The objective of this study is to evaluate the acute effect of the injection of LA, on the proportion of immune cells in the early inflammatory phase, in the site of SN post-compression injury. For this, 15 adult Sprague Dawley rats were used in three groups of nervous compression. A control group, a negative control group with placebo (100 mL PBS) and an experimental group with injection of 100 mL of LA [20mM]. On the third day, the SNs were histologically analyzed and the proportion of immune cells at the injury site was established. The results show that the intraneural injection of LA causes a decrease in the percentage of lymphocytes and an increase in the percentage of macrophages. This is the first work of intraneural injection of LA and demonstrates the modulating effect of LA on immune cells in the peripheral nervous system.

Analysis of the muscle tissue of Wistar rats submitted to the sciatic nerve compression model and cryotherapy / Análise do tecido muscular de ratos Wistar submetidos ao modelo de compressão do nervo isquiático e à crioterapia

ABSTRACT Objective: To evaluate the effects of right sciatic nerve compression and cryotherapy on muscle tissue. Methods: We used 42 male Wistar rats, subdivided in the following Groups Control, Injury 3, Injury 8 and Injury 15 submitted to nerve compression and euthanized in the 3rd, 8th and 15th day after surgery. The Cryotherapy Injury 3 was entailed treatment with cryotherapy by immersion of the animal in recipient for 20 minutes during 1 day, then animals were euthanized at the 3rd day after surgery, and the Cryotherapy Injury 8 and the Cryotherapy Injury 15 was treated for 6 days, and euthanized at the 8th and 15th day after surgery. Functional evaluation was performed by the grasping strength of the right pelvic limb. The right tibialis anterior muscles were evaluated for mass, smaller diameter and cross-sectional area. In the Cryotherapy Injury 8 and the Cryotherapy Injury 15 groups, the hydroxyproline was dosed in the right soles. Results: In the compression there was a significant difference in the Injury Groups compared with the Control Group (p<0.05). In the smaller diameter, the compression in Control Group was higher than Injury 8 (p=0.0094), Injury 15 (p=0.002) and Cryotherapy Injury 15 (p<0.001) groups. The comparison between groups with euthanasia in the same post-operative period, a significant difference (p=0.0363) was seen in day 8th after surgery, and this result in Cryotherapy Injury Group was greater than Injury Group. In the fiber area, Control Group was also higher than the Injury 8 (p=0.0018), the Injury 15 (p<0.001) and the Cryotherapy Injury 15 (p<0.001). In hydroxyproline, no significant difference was seen between groups. Conclusion: Nerve damage resulted in decreased muscle strength and trophism, the cryotherapy delayed hypotrophy, but this effect did not persist after cessation of treatment.

RESUMO Objetivo: Avaliar os efeitos da compressão nervosa do isquiático direito e da crioterapia no tecido muscular. Métodos: Foram utilizados 42 ratos Wistar machos, subdivididos nos Grupos Controle, Lesão 3, Lesão 8 e Lesão 15, submetidos a compressão nervosa e eutanasiados, respectivamente, no 3°, 8° e 15° dias pós-operatório; Lesão Crioterapia 3, tratado com crioterapia, por imersão durante 20 minutos, por 1 dia, e eutanasiados no 3° dia pós-operatório; e Lesão Crioterapia 8 e Lesão Crioterapia 15, tratados durante 6 dias e eutanasiados no 8° e 15° dias pós-operatório. A avaliação funcional foi realizada pela força de preensão do membro pélvico direito. Os músculos tibiais anteriores direitos foram avaliados quanto a massa, menor diâmetro e área de secção transversa. Em Lesão Crioterapia 8 e Lesão Crioterapia 15, foi dosada a hidroxiprolina nos sóleos direitos. Resultados: Na preensão, houve diferença significativa nos Grupos Lesão quando comparados ao Grupo Controle (p<0,05). No menor diâmetro, o Grupo Controle foi maior que Lesão 8 (p=0,0094), Lesão 15 (p = 0,002) e Lesão Crioterapia 15 (p<0,001). Na comparação entre os grupos com eutanásia no mesmo pós-operatório, houve diferença significativa (p=0,0363) no 8° pós-operatório, sendo Lesão Crioterapia maior que Lesão. Na área das fibras, o Grupo Controle também foi maior que Lesão 8 (p=0,0018), Lesão 15 (p<0,001) e Lesão Crioterapia 15 (p<0,001). Na hidroxiprolina, não houve diferença significativa entre os grupos. Conclusão: A lesão nervosa resultou na diminuição da força e em trofismo muscular, e a crioterapia retardou a hipotrofia, porém este efeito não se manteve após o tratamento cessar.

Consideraciones anátomo-clínicas sobre el nervio radial en el codo / Anatomical and clinical considerations about the radial nerve in the elbow

El recorrido del nervio radial a través del codo constituye, para este elemento nervioso, un camino con riesgo de lesiones intrínsecas o extrínsecas. Cambios de la morfología de las estructuras osteomusculares que constituyen el desfiladero del nervio radial, tanto patológicos como traumáticos, pueden determinar el atrapamiento y compresión del mismo, determinando el daño del nervio y/o la inflamación localizada a nivel de las estructuras circundantes. Mediante la disección de 30 preparados, formolizados al 10 por ciento, y el análisis subsecuente de la disposición de las estructuras musculares e inserción de las mismas, se determinaron los posibles puntos de riesgo anatómico que pudiesen alterar al nervio radial o a sus ramos en la canal bicipital lateral o en su ingreso y distribución en el parte proximal del antebrazo (relación con el músculo supinador y los músculos extensores radial largo y corto). Definimos 4 zonas de posible atrapamiento y compresión del nervio radial y sus ramos: 1. Septo intermuscular lateral. 2. Músculo extensor radial corto. 3. Músculo supinator, a nivel de la Arcada de Frohse. 4. Músculo supinator, a la salida de la masa muscular, en el dorso del antebrazo. La compresión del nervio radial a nivel del codo es una de las neuropatías del miembro superior, más frecuentes. El objetivo de este trabajo fue analizar las implicancias anatómicas del recorrido del nervio radial en su pasaje desde el brazo al antebrazo, especialmente las relaciones con las estructuras osteomusculares, cuyas alteraciones pueden ser las responsables de patologías compresivas del nervio radial que puedan llevar a dolor, parestesias, con o sin pérdida sensorial y/o impotencia funcional.

The radial nerve route through elbow constitutes, for this nervous element, a way with risk of intrinsic or extrinsic injuries. Morphologic changes of the structures that constitute the denle of the radial nerve, pathological as much traumatic, can determine it atrapment and compression, determining the damage of the nerve and/or the inflammation located at level of the surrounding structures. 30 forearm-elbow, preserved with formol to 10 percent, were dissected, and the subsequent analysis of the disposition of the muscular structures and insertion of the same ones, will determine the possible points of anatomical risk that they will affect the radial nerve or its branches in the brachial track or in the proximal forearm (relation with the supinator muscle and extensor carpi radialis longus and brevis muscles).We defined 4 zones of atrapment and compression of the radial nerve and its branches: 1. External intermuscular setum; 2. Extensor carpi radialis brevis muscle; 3. Supinator muscle , atlevelof theFrohse's Arch;4. Supinator muscle, when coming out of the muscular mass, in the back of the forearm. The compression of the radial nerve at level of the elbow is one of the frequent neuropathies of the superior member. It is for that reason that the objective of this work consists of analyzing the anatomical aspects of the route of the radial nerve in its passage from the arm to the forearm, specially relations with morphological structures, whose alterations determines pathologies of the radial nerve which can take to pain, parestesies, with lost sensorial and functional impotence.

A Case of Femoral Compressive Neuropathy in AL Amyloidosis

We describe a case of a 54-yr-old AL amyloidosis patient who developed femoral compressive neuropathy due to iliopsoas pseudohypertrophy. The patient, who presented with end stage renal disease, was referred to our clinic because of lower extremity weakness and polyarthritis. Finally, he was diagnosed as having kappa-AL amyloidosis, complicated by femoral compressive neuropathy, hypertrophic amyloid myopathy, amyloid arthropathy, carpal tunnel syndrome, and end stage renal disease. Femoral compressive neuropathy has never been reported in association with amyloid induced iliopsoas hypertrophic myopathy. This report expands the clinical spectrum of AL amyloidosis.

Experimental chronic entrapment of the sciatic nerve in adult hamsters: an ultrastructural and morphometric study

Entrapment neuropathy is a group of clinical disorders involving compression of a peripheral nerve and interference with nerve function mostly through traction injury. We have investigated the chronic compression of peripheral nerves as an experimental procedure for detecting changes in ultrastructural nerve morphology. Adult hamsters (Mesocricetus auratus, N = 30) were anesthetized with a 25 percent pentobarbital solution and received a cuff around the right sciatic nerve. Left sciatic nerves were not operated (control group). Animals survived for varying times (up to 15 weeks), after which they were sacrificed and both sciatic nerves were immediately fixed with a paraformaldehyde solution. Experimental nerves were divided into segments based upon their distance from the site of compression (proximal, entrapment and distal). Semithin and ultrathin sections were obtained and examined by light and electron microscopy. Ultrastructural changes were qualitatively described and data from semithin sections were morphometrically analyzed both in control and in compressed nerves. We observed endoneurial edema along with both perineurial and endoneurial thickening and also the existence of whorled cell-sparse structures (Renaut bodies) in the subperineurial space of compressed sciatic nerves. Morphometric analyses of myelinated axons at the compression sites displayed a remarkable increase in the number of small axons (up to 60 percent) in comparison with the control axonal number. The distal segment of compressed nerves presented a distinct decrease in axon number (up to 40 percent) comparatively to the control group. The present experimental model of nerve entrapment in adult hamsters was shown to promote consistent histopathologic alterations analogous to those found in chronic compressive neuropathies

Sindrome de compresión medular / Spinal cord compression syndrome

Los autores realizan una revisión retrospectiva de 105 casos tratados en el Departamento de Radioterapia del instituto de Enfermedades Neoplásicas atendidos entre 1973 y 1992. La finalidad de la presente evaluación fue determinar la influencia del tratamiento de radiaciones en los pacientes con síndrome de compresión medular en lo referente a paliación de la sintomatología (dolor) y mejoría del déficit funcional (deambulación) porpio de este síndrome. Se recurrió a las fichas de tratamiento del archivo del Departamento de Radioterápia del INEN que tenían el diagnóstico de síndrome de compresión medular y con los números de las historias clínicas procedimos a recolectar los datos que en ella se reportan. Treitidós, de treitinueve pacientes (82 por ciento), que acudieron por sus propios medios a recibir tratamiento luego del diagnóstico de síndrome de compresión medular, continuaron caminando luego de recibir tratamiento. Ocho de sesentiseís pacientes (12 por ciento) que acudieron en silla de ruedas o cama, a recibir tratamiento, pudieron movilizarse por sus propios medios una vez finalizado el tratamiento con radiaciones. Cuarentiún pacientes (64 por ciento) tuvieron mejoría parcial del dolor y quince (24 por ciento) total, luego de recibir tratamiento. En los pacientes que acudieron por sus propios medios y no perdieron esta característica luego del tratamiento, se observó mejoría en su funcionalidad. Concluimos que el tratamiento con radiaciones ofrece beneficio paliativo en los pacientes con síndrome de compresión medular.