Significance of rectal contractions noted on multichannel urodynamics.

Independent rectal contractions are frequently noted when performing multichannel urodynamics and are often considered to be artifactual. In an effort to determine if this activity is indeed significant, we reviewed 430 consecutive multichannel urodynamic studies performed on 289 patients. All studies were performed using an analog recorder at 0.5 mm/sec paper speed. Multichannel pressures included total vesical pressure measured by a urethral catheter, total abdominal pressure measured by a rectal balloon catheter, subtracted detrusor pressure (vesical minus abdominal), and uroflow measurement when possible. Rectal contractions were defined as multiple fluctuations in abdominal pressure as measured by the rectal balloon catheter which were independent of changes in total vesical pressure. These fluctuations could not be reproduced by abdominal stressing or Kegel-type maneuvers. Contractions were noted to be of high or low amplitude, continuous or intermittent. Of the 289 patients, 109 (38%) had a study positive for rectal contractions. Similarly, 168 of 430 studies (38%) were positive. In patients with neurologic disease, rectal contractions were noted in 61/120 (51%). In patients with no history of neurologic disease, 48/169 (29%) had rectal contractions (P < 0.001). Furthermore, when patients without a history of neurologic disease were evaluated with respect to the presence of detrusor instability, a positive study was noted in 27/67 (40%) with instability but in only 21/102 (21%) of patients without instability (P = 0.005). Rectal contractions also occurred with a higher frequency in patients with bladder hyperactivity of any etiology.(ABSTRACT TRUNCATED AT 250 WORDS)