Minimally invasive correction of Hirschsprung disease (congenital megacolon) may be employed in nearly all affected children. Approximately 80% of children afflicted with Hirschsprung disease will have aganglionosis confined to the rectum and rectosigmoid. The principles of operation for Hirschsprung disease are to remove the aganglionic section of the rectum and sigmoid and to perform a coloanal anastomosis in a portion of the colon with biopsy-proven ganglion cells present. In order to define the point of resection and pull-through, biopsies must be obtained. Often a clear transition from spastic, narrow distal bowel to the often thickened, dilated colon can be visualized (Figure 1).
Five percent of patients will have longer segment disease, especially when associated with a syndrome (Down—10%, congenital central hypoventilation, or Von Wardenburg) or a strong family history (5%). Hirschsprung disease is four times more common in boys than in girls. Over 80% of Hirschsprung patients will present with failure to pass meconium in the first 24 hours of life, whereas the remainder may have enterocolitis or varying degrees of chronic constipation. A small percentage will escape detection early in life and may reach adolescence or adulthood and present to adult general surgeons.
Although the vast majority of children may be candidates for corrective operation using MIS techniques, there are a few relative contraindications including active enterocolitis, chronic and severe colonic dilatation, and extension of aganglionosis beyond the terminal ileum.
In many cases, pull-through procedures may be completed by a transanal method alone. Circumstances where laparoscopic assistance is beneficial include transition zones that are unclear or are proximal to the sigmoid colon, difficult transanal mobilization, or concern for bleeding from mesenteric vessels.
Though the majority of children with this disorder have no associated significant anatomic or physiologic derangements, a complete history and physical is required to determine the coincidence of Down syndrome and its associates, neural cristopathies, and family history of Hirschsprung disease or lifelong constipation. Special attention should be paid to the child’s nutritional state, degree of abdominal distension, and signs or symptoms of enterocolitis.
In general, mechanical bowel preparation is not required in neonates. However, older children may have a significant amount of stool stored within the colon that must be washed out by both antegrade and retrograde means. A complete blood count with or without a type and cross are obtained to ensure adequate red cell mass. Urinalysis may be needed if symptoms are evident, as urinary stasis and infection may coexist in a child with chronic megarectum. Single-agent preoperative antibiotics such as a second-generation cephalosporin should be administered. In the operating room after the induction of anesthesia, the surgeon should perform rectal irrigations until the effluent is clear prior to initiation of the operation.