The effect of rectal distension on bladder function in patients with overactive bladder

Aims To investigate the effect of rectal distension on bladder sensation volumes and the number of detrusor contractions in patients with overactive bladder (OAB) symptoms. Methods A prospective randomized study included patients with OAB symptoms. Multichannel urodynamic studies were completed with and without rectal balloon distension. Bladder sensation volumes and detrusor contractions were compared. Results Twenty-six patients were included in the study. The mean age was 67 years and mean BMI was 28.3kg/m ². Bladder sensation volumes were lower with rectal distention as follows: normal desire to void (139ml SD, ±114 vs. 197ml SD ±150, P=0.01), strong desire to void (260ml SD ±171 vs. 330ml SD ±172, P=0.01), and maximum cystometric capacity (326ml SD ±183 vs. 403ml SD ±180, P=0.0001). There was no difference in the number of detrusor contractions or the bladder volume at which the first detrusor contraction had occurred with and without rectal distension. Conclusion Rectal distention in patients with OAB symptoms significantly lowered bladder sensation volumes (normal desire, strong desire, and maximal capacity).