[Etiological analysis and surgical method selection of adult megacolon]

Adult megacolon is a rare disease with heterogeneneous etiology. The treatment schemes of megacolon caused by different causes are also different, but surgery is the final and the most effective method. Due to the lack of early understanding of the disease, many patients have not been clearly diagnosed as adult megacolon and have not been properly treated. This article classifies adult megacolon according to the etiology and summarizes its surgical options. For adult Hirschsprung's disease, modified Duhamel, the Jinling procedure, low anterior resection, or pull-through low anterior resection can be used. For patients with idiopathic megacolon, one-stage subtotal colorectal resection can be selected with adequate preoperative preparations. Some patients admitted to the hospital with emergency intestinal obstruction can be treated with conservative treatment or decompression under colonoscopy followed by selective surgery. For patients with aganglionosis, the procedure is subtotal colorectal resection, the same as that of idiopathic megacolon. The procedure is to remove both the dilated proximal intestine and the stenotic distal intestine, then an ileorectal anastomosis or ascending colon rectal anastomosis is performed. For toxic megacolon, colostomy can be done for mild cases, and for severe infections, subtotal colorectal resection is required. Latrogenic megacolon is mostly caused by segmental stenosis or lack of peristalsis, resulting in chronic dilatation of the proximal end and the formation of megacolon. It is necessary to choose a reasonable surgical procedure according to the specific conditions of the patient. The first choice for the treatment of acute colonic pseudo-obstruction syndrome is decompression under colonoscopy. For those with the secondary changes in the intestine, ostomy is still the most effective surgical procedure, but should be performed with caution.