External Anal Sphincter Electromyography Research Articles

Clinical uro‐neurophysiological investigation in multiple sclerosis

Subjective complaints of urinary dysfunction are common in multiple sclerosis patients. Uro‐neurophysiological investigation, namely somatosensory evoked potentials (SEP) to stimulation of tibial and pudendal nerves, sacral reflex measurements and external anal sphincter electromyography (EMG) were employed in a group of 21 patients with mild to moderate multiple sclerosis and urinary symptoms. Tibial SEP showed abnormality in 86% and pudendal SEP in 48% of patients. Sacral reflexes were abnormal in 33% and external anal sphincter EMG showed abnormalities in 42% of patients (54% of women and 13% of men). Even in multiple sclerosis patients with urinary complaints tibial SEP seem to be more useful in evaluating nervous system dysfunction than pudendal SEP. On the other hand, abnormal pudendal SEP acconmpanied by normal tibial SEP may strengthen the suspicion of a conus lesion, the presence of which is some patients seems to be the cause of otherwise unexplained abnormalities of external anal sphincter EMG and sacral reflexes.

Functional obstructive defaecation

Objective: To study patients with obstructive defaecation to determine quantitatively its pathophysiology and homogeneity. Design: Twenty-two patients with obstructive defaecation were studied by isotope proctography and by conventional methods for quantitative analysis of the pathophysiological factors involved. Methods: Examination of the patients included ano-rectal manometry, the rectal balloon expulsion test, pelvic floor electromyography and isotope proctography. Eleven asymptomatic subjects were studied for comparison. Results: Pelvic floor electromyography revealed increased 'straining electromyographic activity' in all patients (P< 0.001). Patients with obstructive defaecation had impaired rectal sensation and were unable to perform a complete rectal evacuation (54% rectal evacuation) on isotope proctography. The defaecation time was prolonged and was associated with a reduced defaecation rate. Simultaneous recording of intrarectal pressures and external anal sphincter (EAS) electromyography during proctography revealed increased intrarectal pressure (P<0.0001) and EAS electromyographic voltage (P<0.01) during evacuation. The anorectal angles correlated with the pelvic floor movement and the anismus index. The anismus index in these patients correlated with the intrarectal pressure (P<0.02). No increase in the electromyographic voltage of the EAS was observed in any of the control subjects who successfully performed rectal balloon expulsion. Conclusion: Obstructive defaecation is a multifactórial condition involving derangements of rectal sensation and abnormal activity of the pelvic floor and anal sphincter musculature; its homogeneity is affected by the duration of the process.

Consecutive evaluation of vesico-urethral function in patients undergoing radical retropubic prostatectomy

We evaluated vesico-urethral function after radical retropubic prostatectomy in 18 male patients by consecutive urodynamic studies. At the time of the operation average age was 68 years with a range between 56 to 78 years old. The follow-up period after the operation was over 12 months in all patients. Pathological stage was T1 in 2, T2 in 6, T3 in 8 and T4 in 2 patients. Urodynamic evaluation including uroflowmetry, cystometry, urethral pressure profilometry (UPP) and external anal or urethral sphincter electromyography was performed before and 1, 3, 6 and 12 months after the operation. The status of postoperative urinary incontinence was reported by the patients. Sixty-five per cent of the patients revealed the low compliance bladder less than 10 ml/cm water at one month after the operation, however, most patients had normal vesical compliance and normal cystometrogram at 12 months. Both functional profile length (FPL) and maximum urethral closure pressure (UCPmax) in UPP were markedly lowered immediately after the operation and both indexes were significantly lower even at one year after the operation than preoperative ones. Both the incidence and the degree of incontinence improved during postoperative 12 months; complete urinary control was achieved in 11 patients (61%), stress urinary incontinence was present in 6 patients (33%) and one patient (6%) was still totally incontinent. Shortening FPL was considered to be the risk factor on postoperative urinary incontinence. Resection of bilateral neurovascular bundles and lower UCPmax seemed to have the possibility of the influence on it. Low compliance bladder is also likely to be one of the factors to cause early postoperative incontinence.

Urinary Retention Due to Sacral Myeloradiculitis: A Clinical and Neurophysiological Study

We report 5 cases of sacral myeloradiculitis presenting with transient urinary retention. Neurophysiological testing, including bulbocavernosus reflex, pudendal evoked response and external anal sphincter electromyography, was performed. Parasympathetic pelvic nerves, pudendal nerves as well as the spinal cord seem to be involved to various degrees in this infrequent disorder. (J. Urol., 144: 1206–1208, 1990)

Prolonged anorectal manometry and external anal sphincter electromyography in ambulant human subjects

We have developed a method for prolonged combined anorectal manometry and electromyography (EMG) of the external anal sphincter in ambulant subjects. Fourteen healthy volunteers were studied for a total of 284 hr (mean of 20.3 hr/subject). Anorectal manometry was performed using a probe with twin pressure sensors. EMG was recorded by one indifferent and two differential silver-silver chloride surface electrodes positioned 0.5-0.75 cm from the anus on either side. The sampling reflex occurred frequently and was significantly (P less than 0.001) more common during wakefulness than during sleep and also following meals than during fasting (P less than 0.01). The passage of flatus was associated with transient relaxation of the anal canal in 19% of episodes. In contrast, there was a contractile episode with no preceding relaxation in 75% of episodes. The anal sphincter had significantly (P less than 0.05) more action potentials (APs) during the day (12.8 +/- 3.2 APs/10 min) than at night (1.6 +/- 1.3 APs/10 min). During micturition, anal canal pressure rose (mean 15 mm Hg) in association with powerful external anal sphincter contractions. Our data show that, normally, contractile activity both in the anal canal and external anal sphincter maintains fecal continence during micturition and the passage of flatus. The technique should lead to a better understanding of the normal mechanisms of fecal continence during waking and sleep and of the pathophysiology of disorders of anorectal function.

External anal sphincter electromyography (SAE) in patients with myotonic dystrophy

External anal sphincter electromyography (SAE) in patients with myotonic dystrophy

Anorectal function in normal human subjects: effect of gender.

Multiport anorectal manometry and external anal sphincter (EAS) and internal anal sphincter (IAS) electromyography were conducted in 15 males (41 +/- 3 years) and 20 females (43 +/- 2 years; 5 nulliparous) during rest, maximum conscious sphincter contraction, rectal distension and increases in intra-abdominal pressure. The basal pressure declined within 15 minutes of insertion of the manometric probe to a stable plateau, 55 +/- 4% of the initial value. The maximum basal (91 +/- 5 vs 61 +/- 6 cm water; mean +/- SEM), minimum basal (43 +/- 7 vs 27 +/- 3 cm water) and the maximum squeeze pressures (257 +/- 20 vs 107 +/- 13 cm water) were higher (p less than 0.05) in males than females. Distension of a rectal balloon caused a reduction in pressure in all anal channels, that increased in depth and duration as the distending volume was increased. These anal relaxations were associated with rectal contractions and transient increases in the electrical activity of the EAS. Upon deflating the balloon, the anal pressure increased to values that exceeded the pre-inflation values. The pre-inflation (89 +/- 4 vs 49 +/- 4 cm water), post-inflation (104 +/- 9 vs 62 +/- 7 cm water) and residual (47 +/- 4 vs 30 +/- 2 cm water) pressures during rectal distension were significantly higher in males than in females (p less than 0.05). The higher residual pressure in males was associated with a higher EAS index during rectal distension (0.94 +/- 0.10 vs 0.65 +/- 0.10 mv s; p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

A Disposable Anal Plug Electrode for Pelvic Floor/Anal Sphincter Electromyography

During the last year we developed a disposable anal plug electrode for pelvic floor/external anal sphincter electromyography. The electrode consists of 2 disposable silver chloride surface electrodes mounted on a trochlear-shaped sponge. Testing of the new electrode with simultaneous registration of external anal sphincter electromyography using a coaxial needle electrode showed synchronous electromyographic patterns. In clinical urodynamic studies, including 48 cystometry studies with anal sphincter electromyography and 48 pressure-flow electromyographic studies, the electrode provided technically good and reliable electromyograms.The electrode design secures good contact to the recording surface and a safe fixation of the electrode during recording. The compressibility of the electrode might circumvent the problem of possible detrusor reflex inhibition induced by conventional hard anal plug electrodes. We recommend this technique for anal sphincter electromyography, since it is simple, reliable and without discomfort, and it does not require sterilization of the electrode.

Prognostic Value of Urodynamic Testing in Myelodysplastic Patients

We herein describe the clinical progress of 42 myelodysplastic patients studied urodynamically and followed for a mean of 7.1 years. Urodynamic evaluation included urethral pressure profilometry, simultaneous determination of urethral pressure, intravesical pressure and external anal or external urethral sphincter electromyography with fluoroscopic voiding cystourethrography. Assessment of urethral function showed 36 patients (86 per cent) with an open vesical outlet and nonfunctional proximal urethra. Cystometrography revealed that 7 of 42 patients (17 per cent) had reflex detrusor activity: 4 with coordinated micturition and 3 with detrusor-sphincter dyssynergia. Thirty-five patients (83 per cent) had areflexic detrusor dysfunction: 5 with atonic detrusor response and 30 with a progressive increase in pressure with increasing volume. The intravesical pressure at the time of urethral leakage was 40cm. water or less in 20 patients and at pressures greater than this value in 22 patients. No patient in the low pressure group had vesicoureteral reflux and only 2 showed ureteral dilatation on excretory urography. In contrast, of the patients in the higher pressure group 15 (68 per cent) showed vesicoureteral reflux and 18 (81 per cent) showed ureteral dilatation on excretory urography. Thus, a striking relationship between the urethral closure pressure and intravesical pressure at the time of urethral leakage and the clinical course in this group of myelodysplastic patients is demonstrated. Every patient with a normally closed vesical outlet was continent on intermittent catheterization and an anticholinergic agent, while only 60 per cent of patients with open bladder outlets similarly treated achieved good urinary control and none was dry. An artificial sphincter device would seem to be a reasonable method to achieve urinary control in the latter patients but the detrusor response to filling also must be considered. Detrusor hypertonia should be controlled or controllable before a sphincter augmenting device can be used safely. Treatment options for patients with high urethral closure pressures include intermittent catheterization and anticholinergic medications or a sphincter ablative procedure to decrease the outlet resistance combined with anticholinergic therapy and implantation of an artificial sphincter. However, only longer followup will determine if these therapeutic regimens will prevent upper urinary tract deterioration.