Resection is the main treatment for Hirschsprung disease, the purpose of which is to remove the diseased intestinal canal and pull the intestinal canal innervated by the normal nerve to the anus for anastomosis to maintain normal function of the anal sphincter and achieve the purpose of continuity of digestive tract reconstruction[12]. In recent years, the one-stage radical Soave operation of the transanal megacolon[13] has been widely carried out because laparotomy is avoided; there is also less trauma, less bleeding and rapid postoperative recovery. However, it is only suitable for the short segment type and some infants with the common type of megacolon. The application of laparoscopy can resolve the technical limitations of the Soave transanal megacolon and reduce the trauma of laparotomy, which highlights its minimally invasive features.
Although laparoscopic surgery has many advantages, because of the small abdominal cavity in children, abdominal distension often affects the laparoscopic visual field, resulting in abdominal organ injury, defective intestinal tube judgement, and normal laparoscopic operation[14]. We took the following measures to reduce abdominal distension and the difficulty of the operation, which ensured a smooth operation and avoided or reduced the conversion to laparotomy. First, we chose an experienced anaesthesiologist to avoid prolonged mask oxygen supply and repeated tracheal intubation. If there is obvious gas accumulation in the gastric vesicle, we can properly adjust the position of the gastric tube, keep the gastric tube unobstructed, and expel the gas from the stomach. Second, insertion into the anal canal or adult gastric canal through the anus and insertion of the narrow segment into the dilated segment was performed to discharge the intestinal gas. Third, the small intestine often accumulates gas dilatation in the total colon type megacolon. The epidural catheter can be inserted through the abdominal wall to the dilated small intestine to eliminate the gas in the dilated small intestine and eliminate abdominal distension. Through the above measures to eliminate abdominal distension, laparoscopic surgery was successfully completed for all the children in this study, and no cases were converted to open surgery.
Enterocolitis is the most common and serious postoperative complication of Hirschsprung disease, with an incidence of 2-33%[15,16]. Some scholars believe that the occurrence of enterocolitis is related to incomplete colorectal obstruction[17], but we have observed that enterocolitis still occurs despite a smooth operation for most children, standard anal dilatation after the operation, and no obvious stricture or obstruction at the distal end of the colon. Therefore, we believe that in addition to colon obstruction, it is important to have low immunity in the body or intestine, to reduce surgical trauma and to avoid an imbalance of the intestinal flora. All the children in this study were cured after conservative treatment, and some of the children with recurrent enterocolitis recovered gradually with age and improvement in immune function.
Dirty defecation is a common postoperative complication of Hirschsprung disease. The main reasons are injury to the anal sphincter or excessive traction of the anus during the operation. When the colon is pulled out of the anus, the anal sphincter is damaged, leading to dysfunction of the anal sphincter. The occurrence of some dirty defecation is also related to congenital anal sphincter dysplasia[18]. Therefore, the activity in the perineum should be gentle during the operation to avoid excessive traction of the anus; injury of the levator anal muscle should also be avoided during laparoscopic free retroflexion of the intestine. In this study, the children with dirty defecation were not found to have congenital dysplasia or congenital loss of the anal sphincter by MRI, and all were cured after exercise training of the anal sphincter.
The causes of recurrence of constipation after the operation are as follows[19,20]. 1. The rectum muscle sheath without ganglia was retained too long. There was no incision or an insufficient incision of the posterior wall of the rectal muscle sheath during the operation. 2. The resection of the diseased intestine was insufficient, from a long segment megacolon to a short segment or ultra-short segment megacolon. 3. Secondary ganglion cells develop poorly due to improper operation, proximal intestinal injury, or ischaemia. 4. During the operation, the abdominal cavity was widely separated, and the blood vessels were damaged, resulting in spasm caused by insufficient blood supply to the internal sphincter and anal stricture, resulting in constipation recurrence. 5. Enterocolitis is also an important cause of constipation recurrence. In this study, 5 patients with constipation recurrence and 2 with conservative treatment improved after the operation. One patient had recurrent, persistent constipation after the surgery, and radiography showed colon dilatation. Considering that the resection scope was not sufficient, we resected the dilated segment. In one case, frozen pathology revealed a long segment megacolon; the whole colon was pathologically confirmed in paraffin-embedded samples after the operation, and the radical extubation operation was performed again. One case of Hirschsprung disease was complicated with megacolon-like disease with insufficient intestinal resection, resulting in a recurrence of constipation, which was cured by reoperation. Therefore, the cause of abnormal defecation after the operation must be found. After excluding anastomotic stricture, it should be clear whether development of the intestinal nerve is normal and whether it is complicated by megacolon. It has also been suggested that the pathological diagnostic criteria and pathologists’ experience should be emphasized in the radical resection of megacolon.
There are several limitations of our study. First, this was a single-centre study, and more research from multiple centres is needed to assess the effectiveness and complications of this technique. Second, this study was a retrospective review without a control group.