M. S. FLOYD JR ET AL.
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risk factor for sphincteric erosions and continence rates
are lower in patients presenting for revision surgery for
erosions compared to other causes such as previous ra-
diation therapy. Lai et al. [10] followed four specific
patient groups who underwent artificial sphincter inser-
tion and found the rate of cuff erosion to be 6% occur-
ring at a mean of 19.8 months [3]. However, the four
groups (rad iated, non rad iated, neurogen ic and second ary)
displayed no difference in the rate of complications or
the need for device explant. However, the risk of atrophy,
mechanical failure and the need for revision (compared
to the risks of infection and erosion) did increase as the
study progressed with sphincter cuff atrophy being the
commonest complication.
Two complication types require a surgical approach.
Complications such as infections and urethrocutaneous
erosions require device removal. Separately, complica-
tions such as disconnection or leakage causing fluid ex-
travasation with a resultant pressure fluctuation within
the artificial sphincter frequently require repair, but not
necessary removal [11].
There are reports of unusual presentations of urethral
erosions in patients on steroid therapy who have under-
gone repeated urethral catheterisations without cuff de-
flation in the intensive care setting and who have subse-
quently presented with delayed erosions and worsening
incontinence [12]. Previous authors have alluded to the
role of trauma as a potential aetiological factor in artifi-
cial sphincter erosion but do not mention the mechanism.
[8] Similar to this case all patients were initially man-
aged by removing the infected device.
In this case we report a case of erosion of a urinary
sphincter following blunt trau ma to the scrotum by a dog
necessitating removal of the device and reinsertion of a
fifth sphincter six months later. We believe this to be the
only recorded case of sphincter extrusion caused by blunt
trauma from a domestic animal. Similar to other cases of
delayed erosion due to infection our patient was man-
aged with a staged approach, involving explant of the
damaged sphincter and reinsertion of a new sphincter
after a period of wound healing. Given the previous his-
tory of AUS insertion in our patient and visible cutane-
ous erosion, repair of the affected components was not a
viable surgical option.
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