[The role of low urethral mucosal and submucosal blood perfusion in patients with artificial urinary sphincters].
BACKGROUND
A common complication following insertion of a bulbar AUS is recurrent incontinence, and once other causes have been ruled out, a diagnosis of urethral atrophy is then made. Urethral atrophy probably occurs to a certain degree in all patients with an AUS but the reappearance of incontinence is often attributed to inadequate pressure transfer from the cuff to the atrophic urethra. The normal urethral closure mechanism depends also on passive forces which rely on the integrity of the urethral mucosa and submucosa.


METHODS
Two groups of patients with a first AUS implant which had been in place for more than 1 year were studied (n = 11). Group I consisted of continent patients (n(I) = 6) whereas Group II had significant incontinence due to urethral atrophy (n(II) = 5). Intraurethral pressures (IP) and blood flux (BF) were measured simultaneously with a micro-tip transducer and a laser Doppler flowmeter in each patient. Positional measurements were recorded proximal, within, and distal to the cuff first with the AUS deactivated and then activated.


RESULTS
Group I patients exhibited similar IP and BF at all positions along the urethra. In Group II the IP was similar along the urethra but the BF within the cuff was qualitatively different (non pulsatile) and decreased significantly when compared to either side of the cuff during.


CONCLUSIONS
Continence in patients with artificial urinary sphincters depends not only on the cuff occlusive force but is also dependent on the viability of the mucosal and submucosal tissues. For a given pressure range mucosal and submucosal blood perfusion is determinant. patients with normal blood perfusion would remain continent whereas patients with impaired perfusion would become incontinent.
García Montes
F
F
Institute of Urology and Nephrology, University College of London. fgmontes@wanadoo.es
Mundy
A R
AR
Knight
S I
SI
Craggs
M D
MD
D006801:Humans; D009092:Mucous Membrane / Q000098:blood supply; D011474:Prosthesis Design; D012039:Regional Blood Flow; D014521:Urethra / Q000098:blood supply*; D016741:Urinary Sphincter, Artificial