Arterias sigmoideas: bases para una nueva clasificación / Sigmoid arteries: bases for a new classification

Las arterias sigmoideas son ramas de la arteria mesentérica inferior e irrigan al colon sigmoideo. Se originan del tronco de las arterias sigmoideas. Esta es la descripción más frecuente según los autores consultados. El objetivo fue analizar las variaciones en el origen y distribución de las arterias sigmoideas mediante disección. Se utilizaron 13 preparados cadavéricos formolizados al 10 %. Se disecó la cavidad abdominal para identificar a las arterias sigmoideas. Se evidenció su bifurcación paralela al colon sigmoideo. Se lo delimitó mediante reparos palpables. Patrón I: 4 casos (30,8 %). Variante de la arcada sigmoidea como rama colateral de la arteria mesentérica inferior. Tipo Ia: 1 caso (25 %). Sin asociaciones. Tipo Ib: 1 caso (25 %). Asociada al tronco sigmoideo. Tipo Ic: 2 casos (50 %). Asociada a arterias sigmoideas accesorias. Patrón II: 6 casos (46,2 %). Variante del tronco común entre arteria cólica izquierda y arterias destinadas al colon sigmoideo. Tipo IIa: 3 casos (50 %). Sin asociaciones. Tipo IIb: 2 casos (33,3 %). Asociado al tronco sigmoideo. Tipo IIc: 1 caso (16,7 %). Asociado a arterias sigmoideas accesorias. Patrón III: 3 casos (23 %). Variante clásica. Se definió por la ausencia del tronco común con la arteria cólica izquierda y de la arcada sigmoidea. Tipo IIIa: 2 casos (66,7 %). Un número variable de arterias sigmoideas nacen como ramas colaterales de la arteria mesentérica inferior, sin asociarse al tronco sigmoideo. Tipo IIIb: 1 caso (33,3 %). La arteria cólica izquierda emite como rama colateral la primera arteria sigmoidea y se asocia al tronco sigmoideo. 1. El patrón II es el prevalente en este trabajo (46,2 %). 2. La variante clásica no es la predominante en esta investigación (23 %). 3. La arcada sigmoidea tiene 53,8 % de incidencia.

SUMMARY: The sigmoid arteries are branches of the inferior mesenteric artery and supply the sigmoid colon. They originate from the trunk of the sigmoids. This is the most frequent description according to the consulted authors. The objective is to analyze the variations in the origin and distribution of the sigmoid arteries through dissection. 13 cadaveric preparations formalized at 10 % and instruments were used. The abdominal cavity was dissected to identify the sigmoid arteries. Its bifurcation parallel to the sigmoid colon is evident. It is delimited by palpable repairs. Pattern I: 4 cases (30.8 %). Variant of the sigmoid arcade as a collateral branch of the inferior mesenteric artery. Type Ia: 1 case (25 %). No associations. Type Ib: 1 case (25 %). Associated with the sigmoid trunk. Type Ic: 2 cases (50 %). Associated with accessory sigmoid arteries. Pattern II: 6 cases (46.2 %). Variant of the common trunk between the left colic artery and arteries destined for the sigmoid colon. Type IIa: 3 cases (50 %). No associations. Type IIb: 2 cases (33.3 %). Associated with the sigmoid trunk. Type IIc: 1 case (16.7 %). Associated with accessory sigmoid arteries. Pattern III: 3 cases (23 %). Classic variant. It was defined by the absence of the common trunk with the left colic artery and the sigmoid arcade. Type IIIa: 2 cases (66.7 %). A variable number of sigmoid arteries arise as collateral branches of the inferior mesenteric artery, without being associated with the sigmoid trunk. Type IIIb: 1 case (33.3 %). The left colic artery gives off the first sigmoid artery as a collateral branch and is associated with the sigmoid trunk. 1. Pattern II is the most prevalent in this study (46.2 %). 2. The classic variant is not the predominant one in this research (23 %). 3. The sigmoid arcade has a 53.8 % incidence.

Surgical acquired aganglionosis: myth or reality?

PURPOSE: A number of patients operated on for Hirschsprung disease continue to have constipation and abdominal distension for years after surgery. Some authors have proposed that ischemia during surgery may induce secondary aganglionosis. The aim of the present study was to study the effects of ischemia on the enteric nervous system of sigmoid colon in an animal model. METHODS: A surgical model of colonic ischemia was created. 34 adult Sprague-Dawley rats underwent a laparotomy where the marginal arterioles of the sigmoid colon were ligated. After that, a section in the middle segment of the sigmoid colon was performed followed by an anastomosis. The presence of ischemia was assessed by measurement of visible light spectroscopy tissue oximetry and histological examination. Colonic function was assessed by evaluation of stool weight. Rats were killed at 1, 8 and 12 weeks after the operation. 12 rats were sham-operated. Enteric nervous system was evaluated by means of immunohistochemistry with NGFR p75. Quantitative analysis of the number of ganglia and ganglion cells in the myenteric plexus was performed. RESULTS: The surgical model of colonic ischemia significantly decreased tissue oxygenation (pre-surgical = 54.69 ± 7.32 %; post-surgical = 27.37 ± 9.2 %; p < 0.001). There was no disturbance in body-weight gaining in experimental groups and daily stool output did not vary after surgery (pre-surgical = 4.24 ± 0.94 g; post-surgical = 3.82 ± 1 g; p = 0.09). All experimental groups showed persistent ganglia. However, there was a significant decrease in the number of ganglia in all the experimental groups compared to control (1w: 45.91 ± 7.66; 8w: 44.17 ± 10.56; 12w: 36.17 ± 15.06 vs control: 56.88 ± 8.66; p < 0.01). The number of total ganglion cells was significantly reduced only in the experimental group killed at week 12 compared to control (1w: 539 ± 167.58; 8w: 488.58 ± 154.41; 12w: 343.94 ± 161.91 vs control: 513.96 ± 126.97; p < 0.01). The rate of ganglion cells per ganglia was significantly higher in the groups killed at week 1 and 8 versus control group (1w: 11.63 ± 2.53; 8w: 11.11 ± 2.56; 12w: 9.34 ± 1.16 vs control: 9.02 ± 1.81; p < 0.05). CONCLUSION: Long-term follow-up after surgically induced colonic ischemia in the rat showed a decreased number of ganglion cells and ganglia. Nevertheless, it did not produce aganglionosis.

Contribuição à anatomia arterial do cólon sigmóide aplicável a operações de abaixamento / Contribution to arterial anatomy of the sigmoid colon useful for colon lowering down techniques

RACIONAL: A vascularização do sigmóide apresenta variações que podem ser importantes no uso daquele segmento nas operações de intestino grosso. OBJETIVOS: Realizou-se investigação anatômica da vascularização arterial do colón sigmóide para se obter um parâmetro que possa ser aplicado a raciocínio tático nas operações de abaixamento do cólon sigmóide ao períneo, após a ressecção alargada do reto-ânus e seus esfíncteres na neoplasia maligna retoanal. MATERIAL E MÉTODOS: Analisou-se o mesocólon sigmóide de 33 cadáveres formolizados, 22 do sexo masculino e 11 do feminino, através de dissecções destes com os intestinos in situ. Para isso, cateterizou-se a artéria mesentérica inferior, sendo esta contrastada com solução de aguarrás, thinner, látex de cor vermelha e policloreto de vinil. RESULTADOS: A artéria mesentérica inferior originou-se, na maioria dos casos, na face anterior esquerda da aorta abdominal, a uma distância média de 4,3 cm do seu ângulo inferior de bifurcação; a artéria cólica esquerda, em 25 cadáveres, originou-se diretamente da artéria mesentérica inferior. O número de artérias sigmóideas variou de um a cinco. Verificou-se um plano arterial principal que iniciaria na ligadura da artéria mesentérica inferior, abaixo da origem da artéria cólica esquerda, sendo o sigmóide abaixado ao períneo. CONCLUSAO: O conhecimento da vascularização do colón sigmóide e sua observação no transoperatório poderiam orientar a tática e técnica cirúrgica na operação de abaixamento cólico ao períneo e colostomia perineal.

[Arterial anatomy of the sigmoid colon useful for colon take down techniques]. / Contribuição à anatomia arterial do cólon sigmóide aplicável a operações de abaixamento.

BACKGROUND: An anatomic study about the arterial vascularization of the sigmoid was performed in order to obtain guidelines for the surgical treatment of rectal carcinoma. AIM: In the proposed technique, the sigmoid is brought down to the perineum, after radical anal-rectal resection, including sphincterectomy. MATERIAL AND METHODS: Thirty-three anatomical pieces were obtained through in situ dissection of formolized corpses (22 were male and 11 female). Turpentine solution, red marking, polyvinyl chloride were the materials used for preparation after catheterization of the inferior mesenteric artery. RESULTS: The inferior mesenteric artery originated in most cases from the left side of the abdominal aorta, approximately 4.3 cm fromits bifurcation point; the left colonic artery, in 25 cases, originated straight from the inferior mesenteric artery below the left colonic artery, after which the sigmoid would be brought down to the perineum. CONCLUSION: Knowledge about arterial vascularization of the sigmoid could be helpful in the surgical management of rectal cancer.

Consideraciones anatómicas sobre la anastomosis arterial recto-sigmoídea / Anatomical considerations of the recto-sigmoid arterial anastomosis

El conocimiento de la circulación colateral abdominal es importante en las cirugías de la región. Con la finalidad de esclarecer la capacidad de flujos de la anastomosis recto-sigmoídea, su localización y las eventuales variaciones anatómicas, estudiamos las arterias componentes de ella en 43 cadáveres de individuos adultos, brasileños, a los que se inyectó una mezcla de alginato con agua y teñida de tal manera de visualizar su recorrido. Los resultados obtenidos mostraron que la anastomosis recto-sigmoídea está presente en 86.1 por ciento del total de casos; se observó permeable en 70,3 por ciento y se presentó sin permeabilidad en 29,7 por ciento. Estos datos permiten asegurar que esta anastomosis está presente y es funcional en más de la mitad de los casos

A vascularizaçäo arterial do cólon terminal (anatomia cirúrgica da artéria mesentérica inferior) / The arterial vascular supply of the terminal colon (surgical anatomy of the inferior mesenteric artery)

Recorda, o autor, a evoluçäo dos conhecimentos em torno da vascularizaçäo do cólon sigmoide e recto, aplicada à cirurgia desse segmento intestinal. Menciona as primeiras operaçöes de amputaçäo abdómino-perineal do recto e ressecçöes cólicas com anastomose das extremidades intestinais e os primeiros estudos em torno do problema cirúrgicoda vascularizaçäo, feito por SUDECK e ARCHIBALD, em 1908. Após a revisäo dos trabalhos básicos, no assunto, menciona os autores nacionais que têm se interessado pelo estudo da vascularizaçäo do cólon termina, através da contribuiçäo anatômica ou cirúrgica à literatura médica nacional. Descreve a distribuiçäo e as variedades dos ramos da artéria mesentérica inferior. Apresenta o resultado de suas observaçöes, feitas em 100 indivíduos, pós-mortem, relacionando o comprimento do cólon terminal e o número das artérias sigmóideas. Baseado na observaçäo pessoal, apresenta uma classificaçäo e variaçöes das artérias sigmoideas, segundo o número e origem das mesmas, excluídas aquelas que, por suas características especiais possam ser consideradas como anomalias. Descreve a variedade de tipos das artérias sigmoideas, passando depois aos ramos terminais representados nas hemorroidárias superiores e às arcadas marginais. Faz, depois, um estudo da artéria sigmoidea ima e de seu valor anatomo-cirúrgico, esclarecendo e apoiando as razöes que levaram GREGOIRE a substituir a noçäo do "ponto crítico de Sudeck" pela de "zona crítica". O trabalho é ilustrado com vários esquemas e desenhos anatômicos, e acompanhado de vasta bibliografia

Segmented colon ischemia associated with thromboangiitis obliterans

A necrose isquêmica do colo associada à tromboangeíte obliterante é rara e grave, com uma mortalidade elevada. A tromboangeíte abliterante ocorre em pacientes jovens e as manifestaçöes digestivas, raras nesta moléstia, ocorrem posteriormente aos acometimentos dos membros. Relata-se caso de um paciente com necrose segmentar isquêmica de colo com tromboangeite obliterante

Inferior mesenteric artery back pressure and collateral circulation to the distal colon.

The contribution of the hypogastric and superior mesenteric arteries to inferior mesenteric artery collateral (back) pressure (r-IMA) was measured in eight patients who were free from arterial disease and were operated on for small sigmoid carcinoma. Peak and mean r-IMAs were measured after clamping both common iliac arteries and the middle colic artery together with the marginal artery of Drummond. Measurements were repeated after the injection of 50 mg papaverine into the inferior mesenteric artery. For comparison the r-IMA was normalized against the radial artery pressure to create the r-IMA:radial artery pressure ratio. At peak systolic pressure the r-IMA:radial artery pressure was approximately 0.6. This fell with crossclamping of the middle colic artery and marginal artery of Drummond; a slightly greater fall was observed when the common iliac arteries were clamped. The findings were similar when mean pressures were compared. The changes in pressure ratio observed after collateral clamping were slightly amplified by injection of papaverine. These data suggest that the hypogastric arteries make at least as great or a slightly greater contribution to r-IMA than do the middle colic artery plus marginal artery of Drummond. The data also indicate the presence of other substantial collaterals. These findings stress the importance of the hypogastric collateral supplying the sigmoid colon when the inferior mesenteric artery is acutely occluded as it is during aneurysm resection.

[Rectosigmoidal angiodysplasia]. / Angiodisplasia de rectosigmoides.

A case of a three year old child with an angiodysplasia (arterial venous malformation) localized in the sigmoidal rectum is reported. The malformation caused chronic recurrent rectal hemorrhaging. Colonoscopy was the procedure used to diagnose the problem which was later corroborated by arteriography. The affected area was removed.