Vector volume manometry – methods and normal values

Background Vector volume manometry (VVM) can be used to assess patients with fecal incontinence. The VVM may be performed using a station pull through, or an automated technique. Currently no standard technique or equipment exists to assess anal canal VVM. This study aimed to assess the different techniques to produce repeatable results, and generate normal values for the vector volume profile. Methods Anal canal VVM was performed using a water‐perfused system on 12 male and 12 nulliparous female volunteers. Manometry was performed with an automated puller withdrawn at 3 and 25 mm s−1 using a station technique. The VVM profiles were calculated using 4, 8, and 16 channels. Key Results The greatest repeatability of vector volume profile was seen with faster puller speed (25 mm s−1) and with an 8‐channel catheter. Men had higher squeeze volumes, maximal squeeze pressure, average squeeze pressure, and squeeze high pressure zone length. Women had a significantly greater anal canal asymmetry on both station and automated pull through at rest and when squeezing. Squeeze vector volume of pressure, mean maximum squeeze pressure, and the average squeeze pressure were significantly higher when calculated using the station technique. Conclusions & Inferences The faster puller speed has improved agreement between vector profiles, which is most marked during active contraction. The 8‐channel catheters have the greatest agreement between profiles. There is variation in values between automated manometry and the stationary pull through technique. The improved repeatability in automated VVM for healthy controls should improve its diagnostic utility in patients with incontinence.