Transballoon cystometry: a new technique to assess detrusor function after urinary retention

To validate a new urodynamic technique to assess detrusor function in patients presenting with acute urinary retention, using the balloon channel of their Foley catheter (transballoon cystometry), and to use the technique to assess patients presenting in acute retention.

The technique of transballoon cystometry is described and validated in vitro using a specially constructed water manometer, and in vivo on five patients who had a suprapubic catheter in addition to the urethral Foley catheter. Fifty-two patients presenting in acute retention underwent transballoon cystometry one week after catheterization; they were divided according to their clinical presentation into uncomplicated acute retention (41 patients) and acute-on-chronic retention (11 patients). The results from transballoon cystometry were compared between these groups.

The pressure recorded through the balloon channel was equal to that recorded through the lumen of the catheter, both in vitro and in vivo. Patients with acute-on-chronic retention had a larger volume at first sensation, a larger maximum cystometric capacity, higher end-filling pressure and lower maximum detrusor pressure during isometric contraction than patients in uncomplicated retention.

Transballoon cystometry is accurate and easy to perform. The clinical distinction between uncomplicated acute retention and acute-on-chronic retention was supported by the urodynamic data. This test could be used before surgery to identify patients with detrusor failure.