Congenital megacolon was first described by Hirschsprung in 1886 and is also known as Hirschsprung’s disease according to the name of its discoverer. Dr. Swenson started the treatment of congenital megacolon in 1948 by resection of the stenotic and dilated segments and by dragging out the colon and anastomosis of the anal canal. Over the past decades, pediatric surgeons from different countries have made significant progress and improvements in the etiology, pathology, histochemistry and genetic research of megacolon, as well as in the innovation and improvement of surgical techniques, so that the research on the etiology of congenital megacolon, diagnostic methods, surgical results and prevention of complications have been improved. In 1994, Dr. Smith’s laparoscopic-assisted Duhamel megacolon radical surgery and Georgeson’s laparoscopic Soave megacolon radical surgery in 1995 opened the era of minimally invasive megacolon radical surgery. In 1998, Dr. Torre D. L., a Mexican surgeon, proposed a purely transanal megacolon resection, achieving a truly minimally invasive treatment. Minimally invasive is always a consistent principle for surgeons to follow. In our country, laparoscopic megacolon radical surgery and simple transanal Soave have been performed in major hospitals one after another. Compared with open surgery, laparoscopic assisted megacolon radical surgery has well-known advantages such as small incision, good surgical results, less postoperative pain, quicker recovery and shorter hospital stay, etc. Its advantages in intraoperative biopsy of the colon wall, determination of the scope of resection of the intestinal canal and freeing of long segmental megacolon cannot be replaced by other procedures. The advantages of laparoscopic surgery cannot be replaced by other procedures. Laparoscopic surgery is at a very young age, especially for long-segment megacolon and megacolon homoeopathy, where traditional surgical methods have been tested by time, while laparoscopic surgery is at a rapid stage of development and complications are inevitable. Understanding the factors related to the occurrence of complications and mastering their clinical manifestations as well as preventive and therapeutic measures can effectively reduce the occurrence of complications and their serious consequences. Complications associated with laparoscopic-assisted radical megacolon surgery include: internal bleeding, intestinal torsion, anastomotic fistula, anastomotic stricture, small bowel colitis, urinary retention, constipation, fecal contamination, diarrhea, rectal mucosal prolapse, etc. (i) Internal bleeding: mainly mesenteric vascular bleeding and presacral vascular bleeding, rectal muscle sheath bleeding, etc. Laparoscopic megacolon surgery colonic mesentery freeing are done with ultrasonic knife. Proper use of the ultrasonic knife for separation rarely results in bleeding. The following points should be noted in the use of ultrasonic knife in megacolon surgery: ① Vessels below 5 mm can be effectively coagulated. All vessels that are separated from the colonic mesentery can be stopped by using the ultrasonic knife instead of ligation, superior clamping or electrocautery. ② Proper application of cutting and coagulation. The perirectal tissues are loose and the blood vessels are thin, so the cutting speed can be accelerated; the blood vessels at the root of the mesentery are thicker, so it is appropriate to use the method of coagulation before cutting; ③ Correct selection and use of the knife head, it is appropriate to use a 5 mm curved knife head for giant colon surgery, and if thicker blood vessels are encountered, they can be sealed first and then cut off. The pre-sacral freeing is intended to be carried out close to the rectum, and should not be too deep to avoid damage to the pre-sacral vascular plexus on the one hand, and also to avoid nerve injury. Laparoscopic megacolon radical surgery includes Duhamel, Soave, and Swenson surgery, and Soave is currently used more often because it requires stripping the rectal mucosa, and incomplete hemostasis in the muscular sheath is also one of the causes of postoperative internal bleeding. The use of indirect electrocoagulation mucosal stripping method can better control bleeding. (ii) Colonic torsion: Intestinal torsion mostly occurs during the completion of free, colonic dragging out through the anus. The mesenteric side of the dragged out colon should be to the dorsal side; intestinal torsion can lead to poor blood supply to the intestine, intestinal necrosis, anastomotic fistula, etc. It is most likely to occur during laparoscopic subtotal resection of the colon with the ascending colon turned over. Postoperative manifestations of incomplete bowel obstruction may occur in cases of intestinal torsion up to 1800. The management of the free colon in the closed abdominal cavity is a difficult and critical step in this procedure. The main points of treatment are: clamp the root of the appendix, lift the right side of the transverse colon, drag the ileocecal part from the posterior side of the free transverse colon to the subhepatic side, while the assistant pushes the intestinal canal below the transverse colon to the right lower abdomen and drags the small intestine to the left side of the abdomen, with the colonic mesenteric margin vessels against the posterior abdominal wall. The whole process of dragging out and rotation should be monitored under lumpectomy, so that the intra-abdominal intestine and the extra-anal intestine can be rotated at the same angle. (iii) Anastomotic fistula and stenosis: The incidence of anastomotic fistula after laparoscopic megacolon surgery is about 1-2%, and it occurs mostly after subtotal colectomy, which is caused by: insufficient freeing of the towed-out colonic mesentery, high tension of the towed-out colon, which affects the healing of the anastomosis; poor blood supply to the colon (towed-out colon torsion, marginal vascular injury, etc.); infection in the rectal muscle sheath; poor nutritional status and the anastomotic technique. Prevention and treatment: the operation must make the colon dragged down without tension, the colon do not twist, ensure good blood supply to the colon, complete hemostasis in the rectal muscle sheath, prevent infection, and improve the anastomosis technique. Anastomotic stenosis is a late postoperative complication with an incidence of about 5.1%, which is related to anastomotic retraction and torsion, irregular postoperative anus expansion and anastomotic technique. After laparoscopic Soave method radical megacolon resection, the anus should be routinely dilated for more than 6 months, and standardized dilatation should be applied with an anus expander. Stenosis can be effectively treated by dilation. (iv) Small bowel colitis: Small bowel colitis (EC) is one of the most common complications after congenital megacolon surgery and has a high incidence and mortality rate. The incidence is reported to be 20%-40%, and the mortality rate is 3.0%-30.0%, EC can occur before and after radical drag-out surgery. The causes of postoperative small bowel colitis are: postoperative anastomotic stricture, persistent spasm of the internal sphincter, retention of stool, and damage to the intestinal mucosal barrier. Prevention and treatment: regular postoperative anal dilation for 3-6 months; diet abstinence, anti-inflammatory, maintenance of water-electrolyte balance, warm saline enema, etc. (v) Postoperative urinary retention: the incidence is about 3.4%, which may be related to the damage of pelvic plexus during surgery. The ultrasonic knife should not be close to the bladder as much as possible when freeing the rectum, so as not to affect the postoperative bladder emptying by heat conduction. At the same time, the posterior wall of the rectum should be released as close as possible to the intestinal wall to avoid damaging the pelvic plexus and affecting the bladder function, leading to urinary retention. Postoperative catheters are routinely left in place and opened regularly, and then removed when bladder function is restored. (vi) Fecal soiling, constipation and fecal incontinence: The incidence of postoperative fecal soiling is about 12%, manifested by normal defecation and control, but often small amounts of feces and fecal juice stain the underwear. The recent postoperative anal feces is mainly related to the relaxation and paralysis of the internal anal sphincter, which is mostly recovered within 2-3 months. Constipation and incontinence may occur in all types of radical surgery for congenital megacolon (about 5%), and the causes vary. The causes of fecal incontinence in laparoscopic Soave megacolon resection are: 1. the presence of a large number of receptors within about 1.5 cm above the dentate line, which may be damaged during megacolon resection; 2. damage to the internal sphincter (e.g., violent dilation, pulling, etc.) or even removal of the internal sphincter; 3. the function of storing stool in the rectal potbelly, which is removed during laparoscopic Soave megacolon resection The laparoscopic Soave megacolon resection removes the entire rectum, resulting in some impact on stool storage and sensory function, and short-term postoperative anal incontinence. 4. Postoperative rectal mucosal prolapse causes fecal incontinence. The main causes of constipation are: residual presence or absence of ganglion cell intestinal segment; anastomotic stenosis; unincised rectal muscle sheath, etc. Avoid excessive stretching of the sphincter during surgery, adequate resection of the diseased colon, “V” shaped resection of the posterior wall of the rectal muscle sheath, and standardized postoperative anal dilation treatment can prevent such complications. (vii) Diarrhea Frequent bowel movements may occur after megacolon surgery due to colonic resection. It is mostly seen after laparoscopic subtotal resection of the colon via anal dragging, and the residual colon is not compensated enough; the number of stools can be as many as 40 or more times, and it can generally return to 2-3 times a day in about 6 months. Most of the absorption function of the colon is in the right hemicolectomy, and the descending colon and sigmoid colon mainly store feces, so the presence of the right hemicolectomy ensures the absorption of water and electrolytes; at the same time, the ileocecal valve is preserved by the subtotal resection of the colon, thus ensuring the absorption and utilization of nutrients in the ileum. Nutritional disorders do not usually occur. Severe perioperative diarrhea can lead to perianal redness, swelling and erosion, which can mostly be cured after local care; meanwhile, intravenous rehydration usually does not lead to disturbance of water, electro-mediator and acid-base balance, and some cases are relieved by oral antidiarrheal agents. (viii), anal canal, rectal mucosal prolapse: the causes of occurrence: the abdominal cavity has been free intestinal tube not all dragged out of the resection during surgery, so that after the anastomosis of the colon and the anal dentate line, with intestinal peristalsis and defecation, so that the loose free intestinal tube nesting prolapse; severe malnutrition children, pelvic floor tissue loosening, rectal prolapse may; postoperative diarrhea, especially after subtotal colectomy stool, can lead to rectal mucosal prolapse; rectal Excessive resection of the muscle sheath. Prevention and treatment: avoid excessive resection of rectal muscle sheaths during surgery, postoperative nutritional support and symptomatic treatment; rectal mucosal resection and anal loop banding are feasible in cases of prolapse.