Significance of rectal contractions during multichannel urodynamic study

BACKGROUND: The influence of rectal contractions on urination was examined using multichannel urodynamic study. METHODS: We reviewed a total of 246 consecutive urodynamic studies. Each study consisted of a uroflow measurement and multi-channel urodynamic study, evaluating total vesical pressure, abdominal (rectal) pressure, subtracted detrusor pressure and perianal electromyography. Rectal contractions were defined as periodic fluctuations over 5 cmH2O in abdominal pressure detected by a rectal balloon catheter. No relationship of these contractions with cough and breathing was observed. RESULTS: Of the 246 patients, 17 (6.9%) had a positive study for rectal contractions. The patients, who had positive rectal contractions, averaged 70-year-old were older than negative subjects averaged 62-year-old. In multichannel urodynamics, the flow rate was significantly decreased, and electromyographic activity was increased at the moment of each rectal contractions. CONCLUSIONS: The rectal contractions are not artifactual and may be regarded as one of causes responsible for urinary difficulty in the elderly.