ANORECTAL MANOVOLUMETRY IN THE DIAGNOSIS OF FECAL INCONTINENCE

PURPOSE: This study was designed to investigate rectal reservoir function and anal pressures in patients with fecal incontinence using anorectal manovolumetry and to evaluate the reproducibility of the investigation. METHODS: Forty-eight patients with fecal incontinence were investigated with respect to anal pressures and rectal volume changes and sensibility in response to stepwise increased rectal pressures (5-60 cm of H2O). Patients with known rectal wall diseases were excluded. Results were compared with those of 25 control subjects investigated in a similar manner. In ten individuals in the latter group, investigation was repeated after 5 minutes and 24 hours. RESULTS: Resting pressure (RP), squeezing pressure (SP), and the difference between SP and RP was lower in patients than in controls (P < 0.0001). There was no significant difference between patients and controls concerning rectal sensibility or compliance (P > 0.05), but there was a correlation between RP and rectal compliance (r = 0.25; P < 0.05) and between SP and rectal compliance (r = 0.30; P < 0.01). There was good reproducibility of RP and SP after five minutes (r = 0.88-0.92; P < 0.001). The day-to-day variation was larger for RP (r = 0.52; P > 0.05) compared with SP (r = 0.89; P < 0.001). Rectal compliance at 40 cm of H2O was reproducible after 5 minutes (r = 0.98; P < 0.0001) and 24 hours (r = 0.88; P < 0.01). CONCLUSIONS: These results indicate that the primary defect in incontinent patients is a sphincter dysfunction. Any reduction in rectal compliance is likely to be a secondary phenomenon.