Urethral sphincter volumes in women with obstructed voiding and abnormal sphincter electromyographic activity

Fowler's Syndrome-The Cause of Urinary Retention in Young Women, Often Forgotten, but Significant and Challenging to Treat

Urinary retention in young women is a relatively rare clinical problem and is often underdiagnosed. In particular, functional causes of urinary retention pose a diagnostic challenge. One of them is Fowler's syndrome, which is associated with impaired urethral relaxation. Fowler's syndrome is characterized by a large bladder capacity, reduced sensation, increased maximal urethral closure pressure, and detrusor underactivity. Several hypotheses have arisen to explain the cause of urethral relaxation disorders: hormonal changes characteristic of Polycystic Ovary Syndrome (PCOS), causing abnormal stabilization of the muscle membrane, primary failure of relaxation of the striated muscle of the urethra sphincter, and increased urethral afferent activity, inhibiting the bladder afferent signals from reaching the brain by potentiating a spinal mechanism of urinary continence. Currently, sacral neuromodulation is the only intervention that can restore an atypical voiding pattern in women with Fowler's syndrome. The therapeutic effectiveness exceeds 70%, although the revision rate is relatively high, exceeding 50%. Well-designed, long-term prospective studies comparing sacral neuromodulation (SNM) with other therapies such as pelvic floor muscle physiotherapy are warranted to offer the best patient-tailored treatment.

Urethral sphincter volume and urodynamic diagnosis

AIM

To compare urethral sphincter measurements in women with different urodynamic diagnoses using three-dimensional transperineal ultrasound (TPU).

METHODS

Women with lower urinary tract dysfunction having urodynamic studies (UDS) were prospectively recruited to this study. A detailed history and vaginal examination were conducted. Saline cystometry was performed and the women were divided into groups according to their urodynamic diagnosis, which were nondiagnostic urodynamics (NUDS), pure detrusor overactivity (PureDO), pure urodynamic stress incontinence (PureUSI) and mixed urinary incontinence (MUDS). Three-dimensional TPU was performed to measure total urethral sphincter volume, striated sphincter volume, core volume, sphincter length and maximum cross-sectional area. The ultrasound measurements were compared with the diagnostic urodynamics.

RESULTS

One hundred fifty women were included in the study. There were 37, 53, 22 and 38 women in the groups of NUDS, PureDO, PureUSI and MUDS respectively. The average striated sphincter volumes in these groups were 1.84 ml, 2.24 ml, 1.32 ml and 1.98 ml respectively. There was no difference in average age, body mass index or presence of prolapse in these groups. All measurements were larger in the PureDO and smaller in the PureUSI group compared with the NUDS group. The measurements in the MUDS group were larger than in the NUDS group and smaller than in the PureDO group but this difference was not statistically significant.

CONCLUSION

The urethral sphincter of women with PureDO is larger than in women with PureUSI. The value in women with MUDS was between the two. The size of the urethral sphincter appears to be related to the pathophysiology.

Clinical and video urodynamic characteristics of adult women with dysfunctional voiding

BACKGROUND/PURPOSE

Dysfunctional voiding (DV) is an abnormality of bladder emptying in neurologically normal individuals where the external sphincter activity increases during voiding. This study investigated the clinical presentations and videourodynamic characteristics of adult women with DV.

METHODS

A total of 1605 women with lower urinary tract symptoms (LUTS) were investigated with videourodynamic (VUD) studies from 1997 to 2010. The clinical urinary symptoms and VUD characteristics of DV were compared with a group of urodynamically normal controls. Antimuscarinic or alpha-blocker treatment according to the chief complaint of storage or voiding LUTS was respectively given.

RESULTS

There were 168 women diagnosed with DV. Detrusor overactivity (DO) occurred in 69% of women with DV. Patients with DV had significantly lower cystometric bladder capacity, higher detrusor pressure, lower maximum flow rate, and larger post-void residual volume than the controls. A total of 114 (67.9%) patients had storage symptoms and 54 (32.1%) had voiding symptoms as their chief complaints among those with DV. Among them, urinary frequency (n = 69, 41.1%) was the most common chief complaint, followed by dysuria (n = 53, 32.1%), and urgency incontinence (n = 26, 15.5%). The incidence of urgency incontinence and dysuria were significantly greater than that in the control group, however, the incidence of frequency, urgency, or nocturia showed no significant difference between DV and control groups. The success rates were 41.2% (n = 47) for antimuscarinic therapy and 51.9% (n = 28) for alpha-blocker therapy in patients with storage and voiding LUTS, respectively (p = 0.366).

CONCLUSION

DO and storage LUTS commonly occurred in women with DV, suggesting DO could be one of the etiology in the pathophysiology of DV. VUD studies yielded a high diagnostic rate for DV in women with LUTS.

Preoperative hesitating urinary stream is associated with postoperative voiding dysfunction and surgical failure following Burch colposuspension or pubovaginal rectus fascial sling surgery

INTRODUCTION AND HYPOTHESIS

We hypothesized that certain preoperative voiding symptoms would be correlated with poorer post-continence surgery outcomes in women.

METHODS

Preoperative voiding symptoms from 655 women were assessed with questionnaires. Outcomes (overall failures, stress-specific failures, and voiding dysfunction) after Burch or sling surgery were measured. Logistic regression models were used to associate preoperative voiding symptoms with postoperative outcomes.

RESULTS

Hesitating urinary stream was associated with voiding dysfunction [OR 2.22, p=0.01], overall [OR 1.57, p=0.03], and stress-specific [OR 1.67, p=0.009] failures. A ten-point increase in preoperative Urogenital Distress Inventory-obstructive (UDI-O) subscore was associated with overall [OR 1.10, p=0.049] and stress-specific [OR 1.21, p<0.0001] failures. Even controlling for severity of POPQ stage, significant associations of hesitating urinary stream with voiding dysfunction, overall and stress-specific failures remained.

CONCLUSIONS

Preoperative hesitating urinary stream and obstructive voiding symptoms were associated with poorer surgical outcomes. Further studies in this area may be fruitful.

[The primary disorder of sphincter relaxation or Fowler's syndrome]

The primary disorder of sphincter relaxation or Fowler's syndrome constitutes the first cause of urinary retention in young women after ruling neurological, iatrogenic and local origins out. It includes painless urinary retention, polycystic ovaries in more than 50% of the cases, high maximum urethral closure pressure, increase in sphincter volume and striated urethral sphincter electromyography abnormalities. So far, the only treatment restoring micturation in this condition is sacral neuromodulation.

Evidence of occult dysautonomia in Fowler's syndrome: alteration of cardiovascular autonomic function tests in female patients presenting with urinary retention

OBJECTIVE

To assess the hypothesis that an occult impairment of the autonomic system might represent one of the mechanisms of urinary disturbance in Fowler's syndrome (FS), in which the pathophysiology of urinary retention is the predominant feature.

PATIENTS AND METHODS

We prospectively investigated 10 women (mean age 43.7 years) with FS, diagnosed by assessing both voiding-phase dysfunction (complete or incomplete retention with a residual urine volume of >150 mL, and a maximum flow rate of <15 mL/s), abnormalities of striated urethral sphincter electromyography (decelerating bursts and complex repetitive discharges), the presence of polycystic ovaries and absence of any apparent usual causes (obstructive, neurological diseases). The women had a urodynamic investigation, electromyographic examination, cystoscopy, brain and spinal cord magnetic resonance imaging (MRI) and cardiovascular autonomic function tests (CAFTs, i.e. heart rate variability to deep breathing, cold-pressor test, Valsalva ratio, blood pressure response to standing, and sympathetic skin responses), for parasympathetic and sympathetic functions. Evidence of dysautonomia, as classically described, was defined by two or more positive CAFTs.

RESULTS

The mean duration of symptoms was 7.9 years; there was urinary retention in six patients (one complete and five incomplete) and the other four complained of straining to void, diminished stream and hesitancy. Five patients were using intermittent self-catheterization. Six patients had two or more positive CAFTs and were considered to have dysautonomia. In all 10 women the clinical neurological and urological examinations were normal with no apparent clinical symptoms of dysautonomia (blurred vision, pupil abnormalities, clinical manifestations of postural hypotension, gastrointestinal symptoms). Brain and spinal cord MRI, cystoscopy, bladder and kidney ultrasonography, sacral-evoked latencies and cortical-evoked responses after pudendal nerve stimulation were normal.

CONCLUSION

There was an occult impairment of the autonomic system in women with FS; this condition might be a pure bladder expression of a generalized but occult dysautonomia, which in some cases might be diagnosed using CAFTs.

The management of female voiding dysfunction: Fowler's syndrome -- a contemporary update

PURPOSE OF REVIEW

Several aspects of voiding dysfunction in women remain under investigation, including standardization of the diagnosis and management of bladder outflow obstruction. This article describes a specific cause of urinary retention in young women, associated with a failure of urethral sphincter relaxation, and a treatment option that can restore voiding in this group of patients - sacral nerve electrical stimulation therapy. Recently there have been advances in the stimulator implantation technique, as well as in our appreciation of its mechanism of action.

RECENT FINDINGS

Advances include the use of ancillary investigations such as urethral function tests as well as better understanding of the clinical profile of these patients. Improvements in the surgical technique include better methods of lead fixation and a less invasive surgical approach. Research suggests the action of neuromodulation is on the afferent pathway, though it remains to be shown whether this is at a spinal or supraspinal level. It is likely that sacral nerve stimulation has an indirect modulatory effect on detrusor contractility rather than a direct effect on the sphincter.

SUMMARY

Experience of sacral nerve stimulation has increased over the past few years, and its application is expanding to other clinical domains. This knowledge has helped improve the therapy, which is particularly effective in the treatment of women with urinary retention. Although how it works is still not fully understood, this is something that is being addressed by ongoing research.

Maximum urethral closure pressure and sphincter volume in women with urinary retention

PURPOSE

In 1988 a syndrome of isolated urinary retention in young women that is associated with electromyographic abnormality of the striated urethral sphincter was described. It was hypothesised that urinary retention resulted from a failure of sphincter relaxation. The electromyographic abnormality causes overactivity of the muscle and may induce changes of work hypertrophy. If the hypothesis that the electromyographic abnormality is the cause of urinary retention is correct, we would expect the urethral sphincter to be enlarged and the urethral pressure profile to be increased in these women. We evaluated the role of static urethral pressure profilometry and transvaginal ultrasound in women in urinary retention.

MATERIALS AND METHODS

A total of 66 women in complete or partial urinary retention underwent electromyography of the striated urethral sphincter using a concentric needle electrode, followed by urethral pressure profile and/or urethral sphincter volume measurement by transvaginal ultrasound.

RESULTS

Maximum urethral closure pressure plus or minus standard deviation was significantly increased in patients with versus without the electromyographic abnormality (103 +/- 26.4 versus 76.7 +/- 18.4 cm. water, p <0.001). Maximum urethral sphincter volume was also increased in women with versus without the abnormality (2.29 +/- 0.64 versus 1.62 +/- 0.32 cm.3, p <0.001).

CONCLUSIONS

The results of this study are consistent with the hypothesis that a local sphincter abnormality is the cause of urinary retention in a subgroup of women. Urethral pressure profilometry and sphincter volume measurement are useful for assessing these cases, especially when sphincter electromyography is not readily available.

Isolated urinary retention in young women, or Fowler's syndrome

A group of women with otherwise unexplained urinary retention occurring as an isolated phenomenon have been shown to have abnormal urethral sphincters, as assessed by electromyography, transvaginal ultrasonographic volume and pressure profile. A questionnaire survey of a number of women diagnosed with the disorder showed that there was a common natural history, and from the results it was possible to build up a profile of the "typical" patient. She is likely to be between 20 and 35 years old and also to have polycystic ovaries. Before the onset of retention she is likely to have had a relatively mild voiding dysfunction, such as infrequent voiding or an intermittent stream. Commonly her first retention episode will follow a triggering event such as an operation or childbirth. The retention is unlikely to resolve but is not associated with the development of other disorders. Neuromodulation of the sacral nerves is the only intervention that has been demonstrated to restore voiding.

Three-dimensional ultrasound: a novel technique for investigating the urethral sphincter in the third trimester of pregnancy

OBJECTIVES

To measure urethral sphincter volume by three-dimensional (3D) ultrasound. To assess the reproducibility of this measurement technique and to compare volumes obtained using 3D ultrasound with volumes calculated from a formula based on 2D ultrasound measurements.

METHODS

Women were recruited as part of an ongoing study of changes to the pelvis resulting from pregnancy and childbirth. One hundred and eleven women in the third trimester of pregnancy (between 32 and 41 completed weeks' gestation) underwent a 3D transvaginal ultrasound scan of the urethra. In 10 cases the scan was analyzed twice by different observers to assess the reproducibility of the measurements from the scans and the results were analyzed using limits of agreement.

RESULTS

The interobserver error was consistent between all the linear, 2D and 3D measurements obtained from the area scanned. There was a significant difference between volumes calculated directly by 3D ultrasound and the approximated volumes from conventional 2D measurements.

CONCLUSIONS

Three-dimensional ultrasound appears to be a useful tool in measuring urethral sphincter volume. The error is consistent with that of linear and 2D imaging. However, the increase in normal range generated by biological variation in all three planes makes 3D ultrasound a more sensitive method of evaluating change to the urethral sphincter.

Dysfunctional voiding in women: which muscles are responsible?

OBJECTIVE

To analyse the striated external urethral sphincter (EUS) and pelvic floor muscles using two different electromyography (EMG) techniques in women with dysfunctional voiding and/or urinary retention.

PATIENTS AND METHODS

Fifteen women (mean age 38.2 years, range 18-61) with dysfunctional voiding and/or unexplained voiding dysfunction associated with urinary retention were examined neurologically and urologically; urodynamics and kinesiological EMG of the bilateral pubococcygeal and external urethral striated sphincter muscles were obtained. In an additional neurophysiological session, concentric-needle EMG of the external urethral sphincter was performed.

RESULTS

Kinesiological EMG recordings revealed inappropriate pelvic floor muscle activation during voiding in 11 and EUS activation in four women. Concentric needle EMG of the EUS revealed complex repetitive discharges in the four women with inappropriate urethral sphincter activation recorded by kinesiological EMG during voiding. Biofeedback training led to improvement in women with inappropriate pubococcygeal activation but not in those with urethral sphincter complex repetitive discharges.

CONCLUSION

Urodynamic examinations in combination with kinesiological EMG examination of the pubococcygeal and external urethral sphincter muscles revealed two groups of women with dysfunctional voiding. Further diagnostic evaluation of such patients with concentric-needle EMG is mandatory. The differentiation of the two groups is therapeutically relevant.