PURPOSE: Intrinsic sphincter deficiency may cause disabling stress urinary incontinence. While some pelvic operations are implicated as a cause of this condition, simple hysterectomy for benign disease is not recognized as one of them. We evaluated the association of simple hysterectomy with intrinsic sphincter deficiency.

MATERIALS AND METHODS: We performed a case control study to assess the association of simple hysterectomy with intrinsic sphincter deficiency in a consecutive group of 387 incontinent women. From 1995 to 1997 we identified 67 patients with and 67 controls without a history of hysterectomy. Further comparison was done after forming a subgroup at low risk for intrinsic sphincter deficiency. All patients were evaluated by a fluoroscopic urodynamic technique and abdominal leak point pressure was determined.

RESULTS: Intrinsic sphincter deficiency was present in 48% of the 67 patients and 24% of the 67 controls. In the lower risk subgroup we noted this condition in 29 patients (52%) and 53 controls (21%).

Intrinsic sphincter deficiency, also called type III stress urinary incontinence, usually causes severe urinary leakage. It may result from radical hysterectomy due to urethral denervation from extensive pelvic dissection (1) . Other cause is urethral vascular damage, as in urethral diverticulectomy or prolonged catheter drainage and pelvic irradiation (2).

When considering case-control studies, it´s important that both groups been similar in all important ways other than the treatment. In other way, the treatment group may not differ from the control group in important determinants of the outcome. In the hysterectomy group a high proportion of patients had a history of stress incontinence surgery (49%). In contrast, controls underwent relatively minimal surgery for stress urinary incontinence. Based on this, a subgroup of patients and controls with no recognized risk factor was created looking for the association between intrinsic sphincter deficiency and simple hysterectomy. But, for us, some nonanswerable questions remains. What´s the number of hysterectomy patients without urethral disfunction ? It has some independent risk value ?