Urinary retention in women: its causes and management

OBJECTIVE: To report the experience of the last 4 years from a centre to which women with voiding difficulties and urinary retention were referred nationally, describing what investigations were helpful in making a diagnosis and the management strategies used. PATIENTS AND METHODS: Women with voiding difficulties and urinary retention remain a diagnostic and management challenge, and those with no anatomical or neurological basis for their symptoms may be dismissed, assuming that their retention has a psychogenic basis. The finding of an electromyographic (EMG) abnormality of the striated urethral sphincter explaining their disorder (Fowler's syndrome) has led to the referral of women for consideration of that diagnosis. Thus we audited the referrals to the centre over a 4-year period of such women. RESULTS: In all, 247 women (mean age 35 years) with complete (42%) or partial retention (58%) were referred; 175 (71%) had urethral pressure profilometry, 141 (57%) had a transvaginal ultrasonographic measurement of the sphincter volume, and 95 (39%) had sphincter EMG. The mean maximum urethral closure pressure difference between patients with an EMG abnormality (101.5 cmH(2)O) and the patients with known other causes of voiding dysfunction (66.2 cmH(2)O) was 35.3 cmH(2)O (P < 0.05). In patients with complete retention there was a significant difference in sphincter volume between those who were EMG-positive (2.14 mL) or EMG-negative (1.64 mL) (P < 0.05). CONCLUSION: These investigations helped to classify the cause of retention in two-thirds of cases. The commonest diagnosis was Fowler's syndrome, in which sacral nerve stimulation is the only intervention that restores voiding.     

Urodynamic prolapse reduction alters urethral pressure but not filling or pressure flow parameters

PURPOSE: To test the hypothesis that advanced stages of pelvic organ prolapse can result in a functional obstruction of the urethra, we studied the effects of manual prolapse reduction on urodynamic and urethral electromyographic parameters in women with stage III and IV pelvic organ prolapse. MATERIALS AND METHODS: Women with advanced pelvic organ prolapse undergoing clinical multichannel urodynamics with concentric needle electromyography of the urethra were invited to participate in this institutional review board approved study. Women underwent filling cystometry and electromyography with prolapse everted and with prolapse reduced. Women were randomized to cystometry order (reduced vs everted). All subjects underwent a third study with prolapse reduction. Maximum urethral closure pressure and quantitative electromyography of the striated urethral sphincter were determined at maximum cystometric capacity. During the pressure flow study voiding parameters, including urethral electromyography quieting, were determined. The nonparametric paired sign test was used to evaluate differences in urodynamic parameters and quantitative electromyography with pelvic organ prolapse reduced and unreduced. Results were considered significant at the 5% level. RESULTS: The 31 participants had mean age of 60 years (range 36 to 78) and 83% were white. There were no clinically significant differences in maximum cystometric capacity, voided volume, maximal flow and detrusor pressure at maximal flow or time to maximal flow between the reduced and everted prolapse states. Prolapse reduction resulted in a clinically and statistically significant decrease in maximum urethral closure pressure (-31%) but it had no impact on quantitative urethral electromyography. CONCLUSIONS: These findings demonstrate that, although prolapse reduction significantly decreases maximum urethral closure pressure, it does not alter intrinsic neuromuscular activity of the striated urethral sphincter. Prolapse reduction does not alter any other filling or pressure flow parameter.     

Urodynamic study of women in urinary retention treated with sacral neuromodulation

PURPOSE: We investigated the action of sacral neuromodulation in restoring voiding function in women with urinary retention attributable to sphincter overactivity (Fowler's syndrome). MATERIALS AND METHODS: We recruited women within retention who were able to void following neuromodulation by temporary test stimulation or a permanent implant. Urethral pressure profiles, cystometry and sphincter electromyography were performed before and after neuromodulation. RESULTS: A total of 30 women 19 to 52 years old were recruited, including 21 with a permanent implant and 9 undergoing temporary stimulation. Mean maximum urethral closure pressure was elevated compared to expected pressure and it did not change significantly after neuromodulation. The electromyographic abnormality persisted during neuromodulation and voiding was often done with an interrupted flow. There was a slight increase in detrusor contractility. CONCLUSIONS: This evidence suggests that neuromodulation does not restore voiding in these patients by a direct relaxant effect on the sphincter. The modest increase in detrusor pressure appears to be sufficient to overcome the resistance of the overactive sphincter.     

The cause and natural history of isolated urinary retention in young women.

PURPOSE: Using a questionnaire mailed to patients we evaluated the course and natural history of urinary retention in women, of which the cause is attributed to electromyography abnormality of the striated urethral sphincter. Previously urinary retention in young women has often been considered to be due to multiple sclerosis or a manifestation of a psychogenic disorder. MATERIALS AND METHODS: A questionnaire was mailed to 216 women with abnormal sphincter electromyography and urinary retention. Of the 112 responses we analyzed the 91 from those who had been in complete urinary retention. RESULTS: Mean patient age at the onset of complete retention was 27.7 years (range 10 to 50). No patients had neurological features indicating a cauda equina lesion or central demyelination and none had progressed to features of a general neurological disorder. Mean maximum bladder capacity at the initial episode of complete retention was 1,208 ml. Of the women 65% reported an event that had apparently precipitated urinary retention, most commonly a gynecologic surgical procedure using general anesthesia. Sacral neuromodulation was the only therapeutic intervention that restored voiding. CONCLUSIONS: The concept of an organic cause of urinary retention in otherwise healthy young women has considerable importance in terms of correct management. Neurological investigation in these women does not reveal underlying neurological disease. It is thought that this disorder is due to a primary failure of relaxation of the striated urethral sphincter.     

Carbon dioxide urethral pressure profilometry before and after external sphincterotomy in spinal cord injury patients

Seven spinal cord injury patients were studied before and after transurethral external sphincterotomy with combined electromyographic and gas urethral pressure profilometry. The technique was simple, rapid, accurate and reproducible in evaluating the completeness of external sphicterotomy. A significant reduction in maximum urethral closure pressure, as well as in the residual urine volume, was a consistent after spincterotomy. The electromyographic profile showed evidence of periurethral striated muscle activity preoperatively in 2 patients with lower motor neuron lesions in whom the bulbocavernosus reflex could not be elicited. Thus, absence of the bulbocavernosus reflex did not eliminate sphincter reflex activity.     

A study of the continence mechanism of the external urethral sphincter with identification of the voluntary urinary inhibition reflex

PURPOSE: The role of the external urethral sphincter in the opposition and interruption of the act of voiding was investigated. MATERIALS AND METHODS: The study included 7 men and 5 women with a mean age plus or minus standard deviation of 38.6 +/- 11.2 years. The bladder was filled with saline up to the urge sensation. Detrusor and posterior urethral pressures were recorded before and upon resisting the reflex detrusor contraction, and upon interrupting voiding by voluntary external urethral sphincter contraction. The test was repeated by interrupting the urinary stream with external urethral sphincter electrostimulation. The electromyography response of the internal urethral sphincter to the suppression and interruption of voiding was documented before and after internal urethral sphincter anesthetization. RESULTS: Suppression of the reflex detrusor contraction as well as of urinary stream interruption by external urethral sphincter contraction voluntarily or by electrostimulation resulted in a significant detrusor pressure decrease (p <0.01) and urethral pressure increase (p <0.001). Internal urethral sphincter electromyography activity, which normally disappears during voiding, was still present. After internalurethral sphincter anesthetization subjects suppressed the reflex detrusor contraction by voluntary external urethral sphincter contraction for a mean of 62.6 +/- 9.6 seconds, after which involuntary voiding occurred. The internal urethral sphincter showed no electromyography activity. CONCLUSIONS: The external urethral sphincter induces continence by preventing internal urethral sphincter relaxation at the detrusor contraction, which is suggested to be reflex in nature and is called the voluntary urinary inhibition reflex, and by mechanically compressing the urethra. Contraction of the external urethral sphincter, which is a striated muscle, mechanically occludes the urethra for a few seconds, by which time the detrusor has relaxed as an effect of the voluntary inhibition reflex.     

Carbon dioxide urethral pressure profiles in males

Carbon dioxide urethral pressure profiles were obtained in a group of continent and incontinent male patients. Cystometry, needle electromyography of the striated urinary sphincter, and cystourethroscopy were also performed in most patients. A characteristic reproducible urethral pressure profile can be obtained in the continent, obstructed, and incontinent groups. The results also showed that the urethral pressure profile is influenced by the activity of the periurethral striated muscle. The urethral profile when performed with other established urodynamic procedures is a useful test in delineating normal and abnormal urinary sphincter function.     

Abnormal electromyographic activity (decelerating burst and complex repetitive discharges) in the striated muscle of the urethral sphincter in 5 women with persisting urinary retention

In five women with urinary retention, recordings from the striated muscle of the urethral sphincter revealed highly abnormal electromyographic (EMG) activity. Using a concentric needle electrode, recordings revealed very striking bursts of activity, referred to here as decelerating burst (DB) and complex repetitive discharges (CRD). Such EMG activity is exceedingly unusual in skeletal striated muscle and resembles most closely the rarely encountered condition of "pseudomyotonia". We suggest that this abnormal activity is associated with a failure of relaxation of the striated muscle of the urethral sphincter, which results in chronic retention.     

Botulinum toxin in the treatment of chronic urinary retention in women.

Six women were identified as having difficulty in voiding or complete urinary retention due to abnormal myotonic-like electromyographic (EMG) activity in the striated muscle of the urethral sphincter. An attempt was made to improve voiding by injection of botulinum toxin into the striated sphincter muscle. Although 3 patients then developed transient stress incontinence, demonstrating that sufficient botulinum toxin had been given to cause sphincter weakness, no patient had significant symptomatic benefit.     

Urethral sphincter electromyography with vaginal surface electrodes: a comparison with sphincter electromyography recorded via periurethral coaxial, anal sphincter needle and perianal surface electrodes

Urethral sphincter electromyography recording via vaginal surface electrodes was compared to simultaneous sphincter electromyographic registrations obtained with a periurethral coaxial needle electrode and perianal surface or needle electrodes in 10 neurologically intact women. Qualitative similarity of the vaginal surface and periurethral needle electrode recordings was found. Based on this and our previous studies, we conclude that electromyographic recording with vaginal surface electrodes offers a simple and reliable technique to evaluate the striated urethral sphincter during routine urodynamic studies in women.     

Female urethral syndrome: Clinical and urodynamic perspectives

Eighteen women with the urethral syndrome were studied urodynamically with synchronous video-pressure flow studies and electromyography of the external urethral sphincter (EUS). When compared with an age and sex matched control group, the most striking finding was a significantly higher than normal maximum urethral closure pressure. Abnormal and low urinary flow rates, instability of the intraurethral pressure at rest, incomplete funnelling of the bladder neck, and distal urethral narrowing during voiding constitute other typical urodynamic findings in the female urethral syndrome. Detrusor-striated sphincter dyssynergia or primary striated sphincter spasm was not observed. Even though striated E US spasticity cannot be excluded as a cause of this syndrome in some patients, an autonomically mediated spasm of the smooth muscle sphincter seems plausible to explain both our urodynamic findings and a favorable response of 4 patients treated with alpha-blocking agents.     

Disposable vaginal surface electrode for urethral sphincter electromyography

During the last 2 years we have developed a disposable vaginal surface electrode for electromyographic (EMG) recording from the urethral striated sphincter. We describe the design of the electrode and report the results of laboratory testing, including directional selectivity of the electrode, electrode impedance, testing for movement artefacts and stability of position. Clinical studies which included 138 cystometries with sphincter EMG, 133 pressure-flow EMG studies and four urethral pressure profile studies with sphincter EMG, demonstrated that the electrode gave technically good and reliable electromyographic data. The registration caused no discomfort to the patient and did not disturb the act of micturition. We recommend this technique for the evaluation of urethral striated muscle activity during urodynamic studies in women, since it is simple, inexpensive and reliable.     

Transvaginal ultrasound of urethral sphincter at the mid urethra in continent and incontinent women

PURPOSE: Few studies are available on imaging the urethral sphincter. We performed transvaginal ultrasonography to examine the muscle in continent and incontinent women. MATERIALS AND METHODS: Transvaginal ultrasonography was performed using a 7.5 MHz. transrectal probe in 19 continent and 69 incontinent supine women. Incontinent cases were classified as urge (14) and stress (55), and included urethral hypermobility (22) and intrinsic sphincter deficiency (33). Cadaver specimens were also examined to confirm the anatomy of ultrasound images. RESULTS: Transvaginal ultrasonography showed the urethra as a round structure consisting of a relatively high echogenic central zone and a relatively low echogenic peripheral zone. Matching ultrasound images with the anatomy of cadaver specimens indicated that the peripheral zone represents rhabdosphincter most reliably at the lateral aspects. Thus, its thickness was measured at the 9 o'clock position of the mid urethra. Mean thickness plus or minus standard error of mean was significantly decreased in stress incontinence compared with continence and urge incontinence (2.14 +/- 0.04, 2.78 +/- 0.08 and 2.87 +/- 0.11 mm., respectively, p <0. 001), while in intrinsic sphincter deficiency it was thinner than in hypermobility (2.00 +/- 0.05 versus 2.35 +/- 0.06 mm., p <0.01). There was no difference in central zone thickness according to continence status. CONCLUSIONS: Urethral structures may be visualized by transvaginal ultrasonography. The rhabdosphincter image was thinner in stress incontinence, especially in intrinsic sphincter deficiency. Transvaginal ultrasonography may be a useful clinical test for examining the morphology of the urethral sphincter muscle in women.     

The etiology of urinary retention after surgery for genuine stress incontinence

Transient postoperative urinary retention after stress incontinence surgery is common, and there is no widely accepted method of hastening the return to normal voiding. The etiology of this retention is poorly understood. Failure of the relaxation of the striated external urethral sphincter has been proposed as an etiologic agent, but has not been documented. Ten patients about to undergo a Burch colposuspension or sub-urethral sling, who demonstrated normal preoperative voiding, were recruited to a study of postoperative retention. Hook-wire electromyographic (EMG)probes were placed into the external urethral sphincter while the patients were under anesthesia, and a suprapubic catheter was placed. We performed instrumented voiding trials 1 or 2 days after surgery while continuously recording urethral EMG and intravesical pressure. Two patients demonstrated normal voiding. Two patients were able to void but demonstrated no EMG silencing. Six patients were unable to void and demonstrated persistent EMG activity. Four of these demonstrated no detrusor contraction, whereas two demonstrated detrusor contractions. All patients resumed normal voiding by clinical parameters within 14 days of surgery. Our study supports other research that suggests that failure of relaxation of the striated urethral sphincter contributes to postoperative urinary retention.     

The neurophysiology of urinary retention in young women and its treatment by neuromodulation

Urinary retention occurring in young women as an isolated phenomenon was often thought to be psychogenic in origin. However, in 1988, Fowler et al. described a syndrome in young women in which urinary retention was the predominant feature and in which electromyography (EMG) of the striated urethral sphincter revealed a striking abnormality. This abnormality, it was postulated, would result in an inability of the sphincter to relax and retention would therefore result. Until recently there was no effective treatment for this disorder except management by clean intermittent self-catheterisation. However, preliminary results of neuromodulation using a Medtronic sacral nerve stimulator have been particularly promising in this group of patients. The response is often spectacular; a woman who has not passed urine per urethram for many months or years will frequently find that within a few hours of insertion of the percutaneous nerve evaluation (PNE) lead, she can void quite normally with little or no residual urine. The precise mechanism of action is yet to be defined, but measurements of the latency of anal sphincter contraction on S3 stimulation during PNE are so prolonged that they can only be the result of an afferent-mediated reflex.     

Electromyographic study of the striated urethral sphincter in type 3 stress incontinence: evidence of myogenic-dominant damages

Objectives. To determine the electromyographic features of the striated urethral sphincter in patients with type 3 stress incontinence (SI) due to intrinsic sphincteric deficiency (ISD).Methods. We performed electromyography (EMG) of the striated urethral sphincter muscle and urodynamic studies in a total of 51 women, 41 female patients with type 3 SI and 10 women with normal urinary control (NUC). The results were analyzed in both groups, and the correlation of EMG findings with the patient characteristics and urodynamic parameters was evaluated.Results. Motor unit potentials (MUP) of SI patients showed significantly shorter duration (P = 0.0014), lower amplitude (P = 0.0008), and larger number of phases (P = 0.0022) compared with those in the NUC group. Thirty (73%) of the SI patients showed an obvious low amplitude (less than 350 μV)/short duration (less than 4.5 milliseconds)/polyphasic pattern and early recruitment of interference activity with low amplitude at voluntary contraction of the striated sphincter, both indicating existence of myogenic damages. These patients showing myogenic damages had significantly lower Valsalva leak point pressure (P = 0.002) and more leakage in the pad-weigh test (P = 0.010) compared with the SI patients without myogenic damage findings.Conclusions. These results suggested that myogenic-dominant damages of the striated urethral sphincter may contribute to the etiology of ISD in most patients with type 3 SI.     

Overactive bladder inhibition in response to pelvic floor muscle exercises

A recent study by the senior author demonstrated that striated urethral sphincter contraction effected the inhibition of vesical contraction and suppression of the desire to micturate, an action suggested to be mediated through the "voluntary urinary inhibition reflex". We hypothesized that the effect of pelvic floor muscle (PFM) exercises on the overactive bladder was mediated through this reflex action. The current communication investigates this hypothesis. A total of 28 patients (mean age 44.8+/-10.2 years, 18 men, 10 women) with overactive bladder and 17 healthy volunteers (mean age 42.6+/-9.8 years, 12 men, 5 women) were enrolled in the study. The vesical and posterior urethral pressures were determined before and after vesical filling reached the volume at which urge in control subjects, and involuntary voiding in the patients, occurred. Intra-abdominal pressure was recorded to obtain detrusor pressure readings. The bladder was refilled to the above volume and the subject asked to hold PFM contractions for 10 s during which the vesical and posterior urethral pressures were recorded. In healthy volunteers, the mean detrusor and posterior urethral pressures at urge to void were 30.6+/-4.8 SD and 18.7+/-3.3 cm H(2)O, respectively. On PFM contraction, the detrusor pressure declined to 11.6+/-1.4 cm H(2)O (P<0.01) and urethral pressure increased to 139.8+/-17.4 cm H(2)O (P<0.001). In patients, the mean detrusor and posterior urethral pressure readings when the bladder was filled to the volume which induced involuntary incontinence, were 28.2+/-4.2 and 17.3+/-3.4 cm H(2)O, respectively; on PFM contractions, the detrusor pressure decreased to 10.6+/-2.1 cm H(2)O (P<0.01), while urethral pressure increased to 86.6+/-7.9 cm H(2)O (P<0.001) and voiding did not occur. In conclusion, PFM contractions led to a decline of detrusor and increase of urethral pressures and suppressed the micturition reflex. These contractions appear to induce their effect by preventing internal sphincter relaxation produced by the micturition reflex. Failure of the internal sphincter to relax seems to cause reflex detrusor relaxation, an action presumably mediated through the "voluntary urinary inhibition reflex". The results of the current study encourage the treatment of overactive bladder with PFM contractions.     

Electromyographic abnormalities in the urethral and anal sphincters of women with idiopathic retention of urine.

Previous concentric needle studies of the urethral sphincter in women with idiopathic urinary retention have found evidence of denervation and reinnervation as well as abnormal patterns of muscle fibre discharge--complex repetitive discharges (CRDs). In order to test the hypothesis that these abnormalities represented a more widespread disease process of pelvic floor function, we carried out an electromyographic (EMG) study of both anal and urethral sphincters in 18 women with idiopathic urinary retention. The urethral sphincter EMG was abnormal in 15 patients. These abnormalities included polyphasic and long duration potentials. Complex repetitive discharges were identified in 8 women. However, abnormalities of the anal sphincter were found in 14 of the 15 patients with abnormal urethral sphincter EMGs, polyphasic and abnormally long duration potentials being found in the anal sphincters of all 14 patients. In addition, 7 of the 8 women who had complex repetitive discharges in the urethral sphincters had similar complex repetitive discharges in their anal sphincters. Women with complex repetitive discharges had a significantly greater proportion of abnormal potentials than women with no such repetitive discharges. These results support the previous findings of electromyographic urethral sphincter abnormalities in women with idiopathic urinary retention, but also suggest that these abnormalities reflect a widespread disease process involving the pelvic floor in such patients.     

Urodynamics in spinal shock patients

We investigated 17 spinal shock patients with traumatic complete cord lesions with cystometry, urethral pressure profile, anal and rectal pressure recordings, and electromyography of the pelvic floor sphincters. Bladder filling was accompanied by an elevation of resistance in the bladder neck area, with a concomitant increase of pressure in the external sphincter zone but without a simultaneous increase of the electromyographic activity. These results indicate an increased sympathetic activity in the smooth muscle component of the entire urethra. In the majority of patients the continuous withdrawal pressure profile had higher values in the membranous urethra than the interrupted withdrawal pressure profile had higher values in the membranous urethra than the interrupted withdrawal pressure profile, revealing the importance of sensory afferents from the urethral mucosal receptors in producing artifactual reflex activity in the pelvic floor muscles. In the majority of interrupted withdrawal urethral pressure profiles higher pressures were recorded in the juxtabulbous region than in the mid part of the membranous urethra. A somewhat decreased electromyographic activity was found in the anal and urethral sphincters at rest. It did not often relate to the amount of resistance recorded in either sphincter. High urethral sphincter pressures and somatic activity of the conus medullaris reflexes show that external urethral and anal sphincters escape spinal shock, the primary characteristic of which is areflexia.