Pacientes com megacólon adquirido sofrem dupla disfunção: a)discinesia e dilatação do cólon, levando-o à inércia e b) a falha na inervação e sensibilidade retal, abolição do reflexo inibitório reto-anal e acalasia. Há vários métodos para quantificar a disfunção da defecação, e os resultados permitem avaliar o grau do distúrbio. Do ponto de vista da fisiologia anal, os métodos existentes são avaliação de sensibilidade por distensão por balão, pesquisa do reflexo reto-anal e proctografia quantitativa. O objetivo foi comparar estes métodos em 29 pacientes com megacólon avançado. Foram examinadas a sensibilidade retal, o reflexo inibitório reto-anal e feitas proctografias. Resultou que o reflexo inibitório reto-anal estava ausente em 79%, e a sensibilidade retal estava prejudicada em todas as medidas. Contudo, não houve correlação entre as alterações da sensibilidade e a presença ou ausência do reflexo. A sensibilidade foi comparada à medida do esvaziamento retal à proctografia. Também aqui o teste de correlação entre a perda de sensibilidade e porcentual de esvaziamento retal não mostrou significância estatística (p=0,382). Concluímos que, embora a quantificação da defecação seja melhor expressada pela proctografia, os exames de fisiologia nestes casos não são correlatos.
Patients with acquired megacolon suffer from a double dysfunction: a) dilatation and inertia of the colon and b) low rectal sensitivity, inhibition of the anorectal reflex and achalasia. There are several methods to evaluate dysfunctions in defecation. However, from an anal physiology point of view, the most appropriate methods are: rectal sensitivity measurement with an air baloon, anorectal reflex verification and quantitative defecography. Our objective was to compare these methods in 29 patients with severe acquired megacolon. The results depicted that the anorectal reflex was absent in 79% of the cases and the rectal sensitivity was reduced in all cases. However, there was no correlation between the inhibition of the anorectal reflex, loss of sensitivity and defecography. The conclusion was that quantitative defecography was a more reliable method for these patients.
The healing of colorectal anastomoses after irradiation therapy continues to be a major concern. The authors evaluated the healing of rectal anastomoses in a rat model after a preoperative 500-cGy dose of cobalt60 irradiation. Thirty-six male Wistar rats were divided into two equal groups: control (group A), and irradiation group (group B). Group B received a single 500-cGy dose of irradiation, and a rectal resection and end-to-end anastomosis was performed in both groups on the 7th day after irradiation. Parameters of the healing process included bursting pressure and collagen content on the 5th, 7th, and 14th days after surgery. In the irradiation group, the mean bursting pressure on the 5th, 7th, and 14th days was 116, 218, and 273 mmHg, respectively. The collagen content assessed by histomorphometry was 9.0, 20.8, and 32%, respectively. In contrast, the control group had a mean bursting pressure of 175, 225 and 263 mmHg, and a collagen content of 17.8, 28.1, and 32.1%, respectively. The adverse effect of irradiation on healing was detectable only on the 5th postoperative day, as demonstrated by lower bursting pressure (P < 0.013) and collagen content (P < 0.008). However, there was no failure of anastomotic healing such as leakage or dehiscence due to irradiation. We conclude that a single preoperative 500-cGy dose of irradiation delays the healing of rectal anastomosis in rats.