Rectosigmoid aganglionosis
Despite successful removal of the aganglionic segment, children with HSCR are at risk for long-term complications affecting bowel function following surgery, including fecal incontinence, obstructive symptoms or constipation, and Hirschsprung-associated enterocolitis (HAEC).1–4 9
Following pull-through surgery for HSCR, typical long-lasting manifestations of impaired bowel control include difficulties to recognize the need to defecate and fecal soiling, while fecal accidents occur less frequently.1 2 4 9 10 Fecal soiling, escape of small amounts of liquid or soft stool, is a common long-term complication affecting up to 50% of adult patients after surgery for HSCR.1 3 5 9 11 12 Fecal soiling often associates with increased defecation frequency especially after endorectal pull-through due to active propulsive peristalsis in the pulled through bowel transversing to the anus in the absence of a normal rectum to serve as a fecal reservoir.13–15 The absence of rectal reservoir in combination with variably impaired sphincter performance and anal canal sensation may result in fecal soiling.13 15 True incontinence, with the inability to hold back defecation, is due to insufficient anorectal sensory and/or sphincter function and is treated with bowel management or a diverting enterostomy.16 In contrast, patients with fecal impaction with resulting overflow incontinence should be considered in the category of obstructive symptoms and approached as described below.15 16
Different aspects of bowel control including prevalence and severity of fecal soiling seem to improve along with age by adulthood,1 3 9 10 although improvement of fecal soiling was not observed in a longitudinal assessment of the same patients at median age of 7.7 and 15 years.17 Among young adults (age ≥18 years), the patient-reported prevalence of fecal soiling and accidents after endorectal pull-through were comparable to general population.1 Still, around 10% of adult patients reported more problematic fecal soiling, occurring at least weekly or requiring use of protective aids, while less than 25% of patients reported any occurrence of fecal accidents.2 5 9 12 In a large Dutch study including 346 patients, prevalence of any type of fecal incontinence, including fecal soiling, was 65% in pediatric and 29% in adult (age ≥18 years) patients, clearly exceeding the prevalence of normal population controls.10
Obstructive symptoms refer to severe difficulty evacuating typically associated with abdominal distension.4 15 18 Although being relatively common during the first years of life, obstructive symptoms are rarely encountered as such beyond childhood unlike constipation.13 15 18 Among adults, constipation occurs in 30%–40% of patients following Duhamel pull-through but only rarely after endorectal pull-through.1–3 5 9 10 12 However, in relation to normal controls, the overall constipation prevalence of 38% was not significantly higher among adult patients, who had mostly undergone Duhamel or Rehbein reconstruction.10 Multiple overlapping factors may cause obstructive defecation and constipation following a pull-through. Mechanical reasons include mainly surgical complications such as anastomotic stricture, twisting of the pull-through and a tight muscular cuff following endorectal pull-through or rectal spur after a Duhamel pull-through. Neural causes include persistently abnormal innervation of the internal anal sphincter with absent rectoanal inhibitory reflex and deficient relaxation, and colonic dysmotility secondary to abnormal enteric innervation of the seemingly normal ganglionated bowel even after adequate pull-through surgery, and a transition zone pull-through, in which the abnormally innervated transition zone was not inadvertently removed.15 18–20 A thorough evaluation of a patient with obstructive symptoms or severe constipation includes anorectal examination, endoscopy, contrast enema, repeat rectal biopsy, anorectal manometry, and colonic manometry. The aim is to establish the underlying pathology for a targeted treatment strategy.15 19 21
Depending on the definition, up to 50% of patients experience HAEC at some point after endorectal pull-through.4 21 However, apart from patients with total colonic aganglionosis (TCA), most enterocolitis episodes are encountered during the first years after the surgery before school age and become exceptional after puberty.1 22 23
Although overall long-term bowel function outcomes seem comparable after endorectal pull-through and Duhamel, some procedure-related differences exist.12 HAEC episodes are over twice as frequent and stooling frequency remains persistently elevated after endorectal pull-through in contrast to Duhamel.5 9 12 24 In addition to clearly higher prevalence of constipation, defects in fecal control may also be slightly more frequent in adults who have undergone Duhamel pull-through likely related to fecal impaction and overflow in aganglionic rectal pouch.12
Extended aganglionosis
In relation to a shorter segment disease, TCA carries markedly more challenging outlook in the long term related to bowel dysfunction and other associated morbidity, and these patients in particular benefit from close individualized multidisciplinary follow-up also in adulthood.25 26 With increasing length of small intestinal aganglionosis, greater attention to diarrhea, growth and nutritional issues is required.22 Patients with near total or total intestinal aganglionosis should be followed up by an intestinal failure unit as they require prolonged or permanent parenteral nutrition and may benefit from complex intestinal reconstructive procedures or even intestinal transplantation.22 23 26–28
In addition to obstructive symptoms, TCA predisposes to more severe and recurrent HAEC episodes, which can localize in the unused bowel distal to a diverting enterostomy, supporting timely removal of the excluded aganglionic bowel.23 29–32 A nationwide Swedish study reported 31% prevalence of obstructive symptoms in patients with TCA at median age of 10 years.33 A greater loss of bowel including a variable segment of the distal ileum with accelerated intestinal transit and decreased fluid absorption leads to frequent loose stools further increasing the possibility of fecal soiling and incontinence.34 Overall, 30%–80% of older children or adolescents with TCA suffered from different degrees of fecal incontinence.35–38
Duhamel and straight ileoanal anastomosis are the mostly used surgical techniques for TCA with no major differences in functional outcomes other than a lower stooling frequency after Duhamel.22 39 While ileoanal anastomosis with J-pouch has provided promising functional results, further studies are needed to clarify whether inclusion of J-pouch increases the likelihood of obstructive symptoms with associated HAEC.26 40 41