Underfilled or overfilled bladder associated with reduced detrusor contractility in bladder outlet obstruction in men

France: French researchers revealed the mechanisms of urinary retention in men with bladder outlet obstruction. They found from a study that reduced contractility was noticed when the bladder was under or overfilled. The study results were published in the journal Neurourology and Urodynamics. 

Urinary retention and voiding dysfunction are some of the lower urinary tract disorders occurring due to bladder outlet obstruction and impaired detrusor contractility. Bladder outlet obstruction is a progressive detrusor contractility alteration causing urinary retention. As there is not much literature on the relationship between detrusor contractility and bladder filling volume in men with lower urinary tract disorders, French researchers conducted a study to evaluate the impact of bladder filling volume on detrusor contractility in case of bladder outlet obstruction in men. 

A prospective multicenter study was carried out in two pelviperineology departments from January to July 2022. Eligible male patients indicated for urodynamics with an IPSS score > 7 were included. Participants with the absence of bladder outlet obstruction in pressure-flow studies were secondarily excluded. The primary endpoint was the maximum isometric detrusor pressure during a stop-test, corresponding to detrusor contractility, measured at 3 filling volumes (50%, 75%, and 100% of cystometric capacity). 

Key findings: 

• Fifty-two patients performed urodynamics, of whom 12 were excluded because of lack of obstruction or inability to perform the stop-test.
• When compared to 50% and 100% filling capacity, detrusor contractility was significantly higher for a 75% bladder filling, with a mean difference of 19.5 and 12.2 cmH2O respectively (p < 0,01). 
• The change in the desire to void between the stop-test at 50% and 75% of capacity resulted in a greater difference in contractility. 
• Only the time from the onset of the urinary disorder was found to affect bladder contractility when compared to the other possible associated factors. 

Thus, this study was the first of its kind to focus on the influence of bladder filling volume on detrusor contractility in patients with bladder outlet obstruction. 

Further reading: Hermieu N, Chesnel C, Teng M, et al. Effect of bladder filling volume on detrusor contractility in men with bladder outlet obstruction [published online ahead of print, 2022 Dec 15]. Neurourol Urodyn. 2022;10.1002/nau.25113. doi: 10.1002/nau.25113