In the absence of organic pathology, ≥2 of the following must occur for >1 month in a child with developmental age < 4 years [4]
1.≤2 defecations per week
2.At least one episode of incontinence per week after the acquisition of toileting skills
3.History of excessive stool retention
4.History of painful or hard bowel movements
5.Presence of large fecal mass in the rectum
6.History of large diameter stools that may obstruct the toilet Accompanying symptoms may include irritability, decreased appetite, and early satiety, which may disappear immediately following the passage of a large stool
In the absence of organic pathology, ≥2 of the following must occur at least once per week for >2 months in a child with developmental age ≥4 years with insufficient criteria for irritable bowel syndrome [5]
1.≤2 defecations in the toilet per week
2.At least one episode of fecal incontinence per week
3.History of retentive posturing or excessive volitional stool retention
4.History of painful or hard bowel movements
5.Presence of a large fecal mass in the rectum
6.History of large diameter stools that may obstruct the toilet
Epidemiology
True prevalence of childhood constipation is unknown, owing to inconsistent reporting and inconsistent definitions in available literature. Moreover, constipation has often been considered a symptom rather than a primary syndrome or disease, which may lead to further underreporting. A recent systematic review found childhood constipation ranging from 0.7 to 29.6 % [IQR 5.3–17.4 %] [6]. Those authors additionally report an equal distribution between male and female sex. The peak incidence is 4–6 years of age [6]. Longitudinal data suggest that the prevalence of constipation is increasing. Since 1979, in the United States, the number of outpatient visits with a complaint of constipation has doubled. Children under 15 years of age have the greatest number of outpatient visits for constipation as a chief complaint [7]. Finally, 30 % of these patients continue to have symptoms after puberty. Historically, it was thought that constipation was a disease of the developed world, but recent studies in the Asian subcontinent and in Africa have dispelled this myth [6]. Despite high prevalence, only a small proportion of pediatric patients with constipation suffer from intractable constipation requiring surgical intervention.
Pathophysiology
Approximately 95 % of all childhood CIC is a result of a functional disorder without anatomical or physiologic etiology, such as severe idiopathic constipation, psychologic/psychosomatic constipation, nutritional constipation, or colonic inertia. The remaining 5 % of cases have an organic, medical, or anatomic explanation. Hirschsprung disease is the most common of these [3]. Neurogenic causes include myelomeningocele, cerebral palsy, and dysmotility syndromes [3]. Additional neuromuscular disorders are chronic intestinal pseudo-obstruction and intestinal neuronal dysplasia. Anorectal malformations are important to distinguish from others, as the surgical management for these disorders will differ. Anatomic malformations giving rise to CIC include anal fissure, anal stenosis, or imperforate anus [3]. Various endocrine disorders have as a symptom, constipation, which is often corrected with medical management of the primary disorder. These include both hyper- and hypothyroidism, hyperparathyroidism, diabetes mellitus, and diabetes insipidus [3]. Cystic fibrosis (mucoviscidosis) is an example of a genetic disorder causing CIC.
Preoperative Evaluation
A thorough history and physical exam stands at the beginning of every workup, with attention to clinical findings associated with anatomic and neurogenic causes of constipation. Typically, a careful history and a focused physical examination are sufficient to make a diagnosis of a functional disorder giving rise to CIC. It is of highest importance to recognize that patients who present with diarrhea or fecal incontinence as a primary symptom may in fact be experiencing pseudo-incontinence caused by chronic constipation and overflow. There are no telltale physical exam findings associated with idiopathic constipation. Abdominal examination may reveal a firm mass in the abdomen, especially in the left lower quadrant or suprapubic region. A perineal examination is crucial to rule out an anorectal malformation. Digital rectal examination may reveal the presence of stool and give clues about rectal tone.
If there is suspicion of metabolic or endocrine cause for constipation, appropriate laboratory workup should be completed. There are no specific laboratory tests that are necessary for diagnosis of constipation. A recent review found insufficient evidence to support routine use of abdominal radiography or colonic transit time studies to diagnose functional constipation. Moreover, no studies investigating rectal ultrasound, anal manometry, suction biopsy, and barium enema met their inclusion criteria and are thus not recommended for diagnosis [2]. However, for the purposes of surgical planning, abdominal X-ray and/or contrast enema may prove to be particularly valuable and rectal biopsies are indicated in all patients with suggestive symptoms for Hirschsprung disease .
Medical Management
Medical management of CIC depends on the underlying etiology of the condition. A combination of laxatives, stool softeners, and enemas is used to achieve symptomatic relief and help to evacuate the colon and thereby maintain continence. Beginning in 2011, the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition (NASPGHAN) joined the European Society for Pediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) to generate a consensus document regarding treatment of functional constipation [2]. Overall their recommendations favor polyethylene glycol (PEG) for maintenance therapy or lactulose if PEG-enemas are not available [2]. For functional constipation, enemas are not recommended as maintenance therapy in children.
Indications for Surgical Management of Chronic Intractable Constipation
Prior to addressing enteral access for ACE administration, it is important to note that chronic incomplete evacuation can lead to progressive dilation of the rectum and sigmoid which is surgically managed in a different fashion. Four groups of patients may present in this manner:
The first are patients with spinal disorders.
The second are patients with anorectal malformations who have undergone prior repair followed by insufficient postoperative bowel management. In these patients CIC related to colonic hypomotility leads to progressive rectosigmoid dilatation, leading to fecal impaction and eventual overflow pseudo-incontinence. These patients may present with incontinence or diarrhea. This can be easily diagnosed on an abdominal plain film or contrast enema revealing megarectosigmoid colon.
Patients with Hirschsprung disease are a third group, who due to impaired proprioception or inadequate rectal motility may present with CIC and subsequent rectosigmoid dilation.
The final group of patients is those with CIC who have failed medical management.
Patients with status post repair of an anorectal malformation may be able to restore normal evacuation with frequent enemas and an aggressive regimen of stimulant laxatives. For patients with irreversible megarectosigmoid due to unaddressed constipation after anorectal malformation repair, Hirschsprung disease, or idiopathic CIC, segmental resection of the dilated sigmoid with a colo-colonic anastomosis is indicated before evaluating enteral access for ACE administration. Sigmoidectomy can be performed in a conventional open operation, laparoscopically, transanally, or in a hybrid technique [8]. In general, a great proportion of the rectum should be preserved in patients with prior repair of anorectal malformations to allow for a reservoir for stool to produce a feeling of fullness. Patients with idiopathic CIC may undergo more complete rectal resection, as sphincter function and proprioception tend to be intact. Patients who have true fecal incontinence are not well served with sigmoidal resection, as it may convert a tendency toward constipation to one toward softer stools, exacerbated by laxative therapy. Thus patients with CIC and true fecal incontinence are better served with enteral access for ACE administration.
When medical management fails to resolve constipation, patients with neurogenic or neuromuscular causes of chronic constipation, anorectal malformations, and patients with idiopathic CIC utilize daily enemas to achieve evacuation. Adherence to a regular bowel management program can achieve social continence for many of these patients, but as they grow older, it becomes more convenient for them to be able to manage enema administration independently. In these patients, ACE administration has been demonstrated to improve quality of life [9, 10]. Patients who have not demonstrated some degree of success with rectal enemas are unlikely to have additional benefit from antegrade enemas. A careful assessment and preparation of the patients is crucial for the success of an antegrade enema operation. At least a 3-month course of retrograde enemas to prove responsiveness and compliance should be completed prior to consideration of enteral access ACE administration. Moreover, ACE delivery may require a lifelong commitment from the patient. Diverting ostomies and colectomy, except as discussed above, are not discussed in this chapter, but in some cases may be alternative surgical options.
Technique for Surgical Enteral Access for Antegrade Enemas
Antegrade enemas have been shown to be effective, and a variety of enteral access surgeries have been devised based on a flap-valve continence mechanism popularized by Mitrofanoff [11, 12].
Malone Procedure
The Malone procedure for antegrade continence enema (MACE) and its laparoscopic equivalent, laparoscopic antegrade continence enema (LACE) , are widely accepted surgical options first described in 1990. The appendix is used to create a catheterizable stoma, allowing access to the cecum [13, 14]. LACE is recommended if no additional procedure is needed to aid in urinary continence. In the classic MACE procedure, a muscle cutting right lower quadrant incision is made, and the stoma is customarily placed in the right lower quadrant. The stoma may be placed higher if the patient is wheelchair bound for ease of access. In recent years, most pediatric surgeons support the minimally invasive LACE approach. The resultant stoma from a LACE procedure is created in the umbilicus, preferably with a continence valve mechanism. LACE is performed under general anesthesia. The patient is positioned supine. A 5 mm port is placed in the umbilicus, and two additional 5 mm ports are placed either within the bilateral iliac fossae or in the left upper and lower quadrants. The cecum is mobilized such that the appendix can easily reach the umbilicus. Care must be taken to preserve the appendiceal vascular supply during mobilization. Creation of a continence valve using the cecum during a MACE or LACE procedure is recommended to prevent retrograde stool leakage. The cecum is mobilized more extensively and delivered extracorporeally, which may require a longer infraumbilical incision. A mesenteric window is fashioned to preserve the vascular supply the appendix. The appendix is folded along its base and the cecum is plicated around the base of the appendix (Fig. 35.1). The umbilical skin is incised in a V fashion for the appendix to skin V-Y anastomosis, which reduces the incidence of anastomotic strictures. To form the appendicostomy, the umbilicus is everted, and a V-shaped incision is made (vertex at the most distal portion of the umbilicus). The skin flap is then sutured around one half the circumference of the conduit and the remaining portion of the conduit is sutured to the umbilical rim V-Y technique) (Fig. 35.2). The stoma is created around a 10–12 French catheter, which should remain in situ for 4 weeks postoperatively.
Fig. 35.1.
Formation of continent appendicostomy . From left to right: plication of the cecum to create continence valve, final position of ostomy and colon with administration of antegrade enema, and final appearance of the suture continence valve. From Alberto Peña, Andrea Bischoff [15]. Reprinted with permission from Springer.
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