Role of anorectal manometry in children with severe constipation

Constipation is one of the most frequent disorders of the digestive tract in children and it can be an important problem in paediatric and surgical practice. Most of the time, the cause is psychological or because of a slowing of colonic transit, but it can be a sign of organic gastrointestinal outlet obstruction. Some patients with chronic constipation are resistant to a medical approach and they present with a severe form of constipation that needs recurrent hospital admission. Anorectal manometry (ARM) is a noninvasive procedure and it helps to explain the mechanisms of defecation disorders. The aim of the present study was to evaluate the role of ARM in children with severe constipation.

From October 2003 to October 2006, in the Paediatric Surgery Unit, 85 children - aged more than 1 year - with severe constipation were seen. The mean age was 5 years (range, 1-13). At presentation, every child had abdominal and rectal examination in order to identify abdominal distension or faecal masses. Bowel preparation with enemas was performed before ARM in patient with a rectal faecaloma. Myoelectric activity of the internal anal sphincter and resting anal tone was recorded; recto-anal inhibitory reflex (RAIR) was tested to exclude Hirschsprung's disease (HD). Anal tone was considered normal until 50 cm H(2)O. When the RAIR was absent, the patient underwent rectal suction biopsies (RSB) for histology and acetylcholinesterase histochemistry. In cases of normal or high anal tone with the RAIR present, the child had bowel cleaning, medical treatment, 2- and 6-month follow-up. Children with ineffective treatment at follow-up underwent RSB. In case of HD, a laparoscopic-assisted endorectal pull-through (ERPT) according to Georgeson's technique was performed.

Seventy per cent of the patients had bowel preparation before ARM. In four patients the ARM was impossible to assess because of crying. In 28 patients, the anal tone result was higher than 50 cm H(2)O and local treatment with anaesthetic agents was used for 8 weeks. Seventeen patients underwent RSB: 11 patients with RAIR absent/unclear, 4 noncooperative children and 2 patients with ineffective medical treatment at follow-up. HD was diagnosed in 2 patients and laparoscopic-assisted ERPT was performed. The remaining patients had good results at 6-month follow-up.

ARM is a noninvasive diagnostic tool to study the mechanism of defecation in children with constipation in order to prescribe the appropriate treatment. This procedure can be used in every child - aged more than 1 year - with severe constipation and assessment of the RAIR can select the cases for RSB.