No role for increased rectal compliance in pediatric functional constipation

Increased rectal compliance has been proposed to contribute to pediatric functional constipation (FC). We evaluated the clinical relevance of increased rectal compliance and assessed whether regular use of enemas improves rectal compliance in children with FC.

A prospective longitudinal study was conducted on children (8-18 years old) with FC. Pressure-controlled rectal distensions were performed at baseline and at 1 year. Rectal compliance was categorized into 3 groups: normal, moderately increased, or severely increased. Patients were randomly assigned to groups given conventional therapy or rectal enemas and conventional therapy. Clinical success was defined as >or=3 spontaneous defecations per week and fecal incontinence <1 per week.

Baseline measurements were performed in 101 children (11.0 +/- 2.1 years); rectal compliance was normal in 36%, moderately increased in 40%, and severely increased in 24%. Patients with severely increased rectal compliance had lower defecation frequency (P = .03), more fecal incontinence (P = .04), and more rectal fecal impaction (P < .001). After 1 year, success values were similar between groups: 42% normal, 41% moderately increased, and 40% with severely increased compliance. Barostat studies performed after 1 year in 80 children (37 conventional therapy and 43 rectal enemas in addition to conventional therapy) revealed that rectal compliance had not changed in either group and had not improved in successfully treated patients.

Constipated children with severely increased rectal compliance have severe symptoms. However, increased rectal compliance is not related to treatment failure. Regular use of enemas to avoid rectal fecal impaction does not improve rectal compliance in pediatric FC.