Clinical neurophysiology and electrodiagnostic testing of the pelvic floor

Neurophysiology of the pelvic floor in clinical practice: a systematic literature review

Neurophysiological testing of the pelvic floor is recognized as an essential tool to identify pathophysiological mechanisms of pelvic floor disorders, support clinical diagnosis, and aid in therapeutic decisions. Nevertheless, the diagnostic value of these tests in specific neurological diseases of the pelvic floor is not completely clarified. Seeking to fill this gap, the members of the Neurophysiology of the Pelvic Floor Study Group of the Italian Clinical Neurophysiology Society performed a systematic review of the literature to gather available evidence for and against the utility of neurophysiological tests. Our findings confirm the utility of some tests in specific clinical conditions [e.g. concentric needle electromyography, evaluation of sacral reflexes and of pudendal somatosensory evoked potentials (pSEPs) in cauda equina and conus medullaris lesions, and evaluation of pSEPs and perineal sympathetic skin response in spinal cord lesions], and support their use in clinical practice. Other tests, particularly those not currently supported by high-level evidence, when employed in individual patients, should be evaluated in the overall clinical context, or otherwise used for research purposes.

Expert consensus document: Advances in the evaluation of anorectal function

Faecal incontinence and evacuation disorders are common, impair quality of life and incur substantial economic costs worldwide. As symptoms alone are poor predictors of underlying pathophysiology and aetiology, diagnostic tests of anorectal function could facilitate patient management in those cases that are refractory to conservative therapies. In the past decade, several major technological advances have improved our understanding of anorectal structure, coordination and sensorimotor function. This Consensus Statement provides the reader with an appraisal of the current indications, study performance characteristics, clinical utility, strengths and limitations of the most widely available tests of anorectal structure (ultrasonography and MRI) and function (anorectal manometry, neurophysiological investigations, rectal distension techniques and tests of evacuation, including defecography). Additionally, this article provides our consensus on the clinical relevance of these tests.

Paradoxical puborectalis syndrome on diffusion-weighted imaging: a retrospective study of 72 cases

This study aimed to evaluate the application value of diffusion-weighted imaging (DWI) for assessing paradoxical puborectalis syndrome (PPS) in patients with obstructive defecation syndrome (ODS). The medical records of 72 ODS patients who underwent magnetic resonance (MR)-DWI and MR-defecography were retrospectively reviewed. The differences in the apparent diffusion coefficients (ADCs) and the thickness of the right and left branches of the puborectalis muscles between the PPS(+) and PPS(−) groups were compared. In addition, the absolute within-patient differences between the right and left branches (ADC, thickness) were compared between the two groups. The absolute difference in ADCs (right branch - left branch) was significantly different between the two groups. Regardless of whether the ADC was acquired through single-ROI (0.10 ± 0.08 vs 0.23 ± 0.18, P = 0.000) or multi-ROI (0.16 ± 0.14 vs 0.27 ± 0.17, P = 0.009) analysis, the PPS(+) patients displayed a lower absolute ADC difference than did the PPS(−) patients. However, there was no statistically significant difference in the ADC value, thickness or the absolute difference in thickness between the two groups. These findings suggest that DWI may have value in quantitatively assessing the puborectalis muscle in ODS patients, whereas the value of puborectalis thickness in such aspect needs further study.

Existe alteração na função dos músculos do assoalho pélvico e abdominais de primigestas no segundo e terceiro trimestre gestacional?

RESUMO O objetivo deste estudo é comparar a função dos músculos do assoalho pélvico no segundo e terceiro trimestre gestacional de primigestas. Foi desenvolvido em duas unidades de Saúde da Família do município de Aracaju (SE). As gestantes foram submetidas a três avaliações da função dos músculos do assoalho pélvico por meio da eletromiografia de superfície: até 16 semanas gestacionais, entre a 24ª-28ª e 34ª-36ª semanas gestacionais. Foram registrados valores de repouso, contrações voluntárias máximas e contrações sustentadas. Os dados foram tabulados no Microsoft Excel e analisados estatisticamente no programa Statistica. Adotou-se um nível de significância de 5% (p≤0,05). Participaram do estudo 19 primigestas, com média de idade de 21,74±3,65 anos. Houve aumento da massa corporal no 3º trimestre gestacional em relação ao período pré-gestacional e diminuição da média do sinal dos músculos do assoalho pélvico durante o repouso ao longo das três avaliações. A musculatura abdominal diminuiu a média do sinal no repouso e durante a contração sustentada nas avaliações 2 e 3 comparadas à avaliação 1. Pode-se concluir que outros fatores, além dos relacionados ao aumento da massa corporal materna, podem estar associados à sobrecarga nos MAP durante a gestação logo no primeiro trimestre. Essa sobrecarga pode fazer que as gestantes apresentem um tônus muscular próximo ao limite superior de referência, alterando o padrão de atividade eletromiográfica principalmente no repouso, a fim de manter a função de sustentação dos órgãos pélvicos e de continência.

Three-dimensional high-resolution anorectal manometry in the diagnosis of paradoxical puborectalis syndrome compared with healthy adults: a retrospective study in 79 cases

OBJECTIVES

The aim of this study is to evaluate the three-dimensional anorectal pressure topography of normal healthy adults and patients with paradoxical puborectalis syndrome (PPS) using a novel three-dimensional high-resolution manometry (3D-HRM) of the anorectum.

METHODS

The 3D-HRM probe has a 6.4 cm long sensing segment that is composed of 256 independent pressure transducers around its circumference. It generates a 3D pressure topographic profile of the anorectum. We evaluated 41 women and 38 men with PPS (median age 52 years), and compared them with 37 women and 34 men who were healthy (median age 51 years). The three-dimensional anorectal pressure topography was evaluated at rest, and during squeeze, stimulated defecation, and balloon inflation.

RESULTS

Maximum resting pressure, mean resting pressure, high pressure zone length, and residual anal pressure were significantly higher in patients with PPS compared with healthy adults (P<0.01 each). The rectoanal pressure differential was significantly lower in the PPS patients compared with healthy adults (P<0.05). There was a characteristic purple high-pressure area in the posterior wall of the pressure cylinder of patients with PPS during stimulated defecation that was absent in healthy adults. The longest diameter and widest diameter of this purple high-pressure area were 1.71 ± 0.25 and 1.07 ± 0.14 cm. The maximum, mean, and minimum pressures of the posterior distal pressure zone were significantly higher in patients with PPS (270.1 ± 8.2, 152.7 ± 4.8, and 51.9 ± 2.7 mmHg, respectively) compared with healthy adults (168.5 ± 11.1, 88.0 ± 5.9, and 30.7 ± 2.8 mmHg, respectively) (P<0.01).

CONCLUSION

Using the 3D-HRM technique, the increase in the resting pressure and residual anal pressure and decrease in the rectoanal pressure differential in patients with PPS compared with healthy adults further indicated the mechanism of this disease. Unlike traditional manometry, the 3D-HRM technique could find, locate, and evaluate the scope and the pressure of the paradoxical contraction of puborectalis muscle, which further indicates the value of manometry in terms of diagnosis.

Pelvic floor muscle activity, quality of life, and sexual function in peri- and recently postmenopausal women with and without dyspareunia: a cross-sectional study

Pelvic floor alterations during menopausal years, resulting from aging and hormonal decline, may lead to several forms of sexual dysfunction. Dyspareunia-pain during sexual intercourse-is among the most frequent. Nevertheless, few studies so far have evaluated pelvic floor muscle function in postmenopausal women with dyspareunia. The authors thus carried out a cross-sectional study to assess myoelectric activity in pelvic floor muscles in peri- and postmenopausal women with and without dyspareunia receiving routine care at an outpatient clinic. In addition, sexual function (using the Female Sexual Function Index) and quality of life (using the Cervantes Scale) were assessed. Fifty-one peri- and postmenopausal women between 45 to 60 years of age (M = 52.1, SD = 4.9) were evaluated, 27 with and 24 without dyspareunia. There were no statistically significant differences in resting muscle activity, maximal voluntary contraction, and sustained contraction between women with and without dyspareunia. There were statistically significant between-group differences on the Cervantes Scale (p =.009) and in all Female Sexual Function Index domains except desire and satisfaction (arousal, p =.019; lubrication, p =.030; orgasm, p =.032; pain, p <.001; desire, p =.061; satisfaction, p =.081), indicating that women with dyspareunia experience worse quality of life and less satisfactory sexual function as compared with women without dyspareunia.

Effect of acupressure in treating urodynamic stress incontinence: a randomized controlled trial

The efficacy of acupressure therapy in managing urodynamic stress incontinence has not been fully investigated. This study evaluates the effects of a validated acupressure protocol for treating women with urodynamic stress incontinence. A randomized, single-blinded, placebo-controlled trial with a before-and-after study design was conducted. Eighty-one women aged between 18 and 60 were recruited at a urogynecology clinic in an acute hospital in Hong Kong. Participants were randomly assigned to an intervention (acupressure) group, a sham group, or a usual care (control) group. A validated acupressure protocol was employed in the intervention group. The intervention comprised three weekly sessions of 30 minutes each for a total of thirty sessions. Outcome measures included pelvic floor muscle strength, number of episodes of urine leakage over four days, self-reported severity of urine leakage, and responses on the Chinese version of the King's Health Questionnaire. No adverse effects were reported. Five percent of the participants dropped out of the study. Intention-to-treat analysis was conducted, the results indicated significant differences in pelvic floor muscle strength across the three groups (H =7.05, p =0.03) and in self-reported severity of urine leakage between the intervention and control groups (Z = -2.48, p = 0.01). Significant improvement in all domains of the Chinese version of the King's Health Questionnaire was evident in the intervention group. Acupressure is a simple and non-invasive intervention that appears to have positive physiological and psychological effects on women with urodynamic stress incontinence. The findings support acupressure as an intervention option for managing urodynamic stress incontinence in women.

The external anal sphincter operates at short sarcomere length in humans

BACKGROUND

The length at which a muscle/sarcomere operates in vivo (operational length) and the length at which it generates maximal stress (optimal length) can be quite different. In a previous study, we found that the rabbit external anal sphincter (EAS) operates on the ascending limb of the length-tension curve, in other words at lengths shorter than its optimal length (short sarcomere length). In this study, we tested whether the human EAS muscle also operates at a short sarcomere length.

METHODS

The length-tension relationship of the EAS muscle was studied in vivo in 10 healthy nullipara women. EAS muscle length was altered by anal distension using custom-designed probes of 5, 10, 15, and 20mm diameter. Probes were equipped with a sleeve sensor to measure anal canal pressure. The EAS muscle electromyograph (EMG) was recorded using wire electrodes. Ultrasound images of anal canal were obtained to measure EAS muscle thickness and anal canal diameter. EAS muscle stress was calculated from the anal canal pressure, inner radius, and thickness of the EAS muscle.

KEY RESULTS

Rest and squeeze stress of the anal canal increased with the increase in probe size. Similarly, the change in anal canal stress, i.e. the difference between the rest and the squeeze, which represents the active contribution of EAS to the anal canal stress, increased with the increase in probe size. However, increase in probe size was not associated with an increase in the external anal sphincter EMG activity.

CONCLUSIONS & INFERENCES

Increase in EAS muscle stress with the increase in probe size, in the presence of constant EMG (neural input), demonstrates that the human EAS muscle operates on the ascending limb of the length-tension curve or at low sarcomere lengths. We propose that surgically adjusting EAS sarcomere length may represent a novel strategy to treat fecal incontinence in humans.

Pelvic floor anatomy and applied physiology

Pelvic floor muscles have two major functions: they provide support or act as a floor for the abdominal viscera including the rectum; and they provide a constrictor or continence mechanism to the urethral, anal, and vaginal orifices (in females). This article discusses the relevance of pelvic floor to the anal opening and closure function, and discusses new findings with regards to the role of these muscles in the vaginal and urethra closure mechanisms.

Manometric, sensorimotor, and neurophysiologic evaluation of anorectal function

With advances in diagnostic technology, it is now accepted that in the field of functional bowel disorders, symptom-based assessment is unsatisfactory as the sole means of directing therapy. A robust taxonomy based on underlying pathophysiology has been suggested, highlighting a crucial role for physiologic testing in clinical practice. A wide number of complementary investigations currently exist for the assessment of anorectal structure and function, some of which have a clinical impact in patients with functional disorders of evacuation and continence by markedly improving diagnostic yield and altering management. The techniques, limitations, measurements, and clinical use of manometric, sensorimotor, and neurophysiologic tests of anorectal function are presented.

Anorectal motor disorders

Anorectal motor disorders such as faecal incontinence, chronic anorectal pain and solitary rectal ulcer syndrome are common in the community. They cause psychological distress, affect quality of life, and pose a significant economic burden. In recent years, many strides have been made in the diagnostic criteria and in the mechanistic understanding of anorectal disorders. The use of innovative manometric, neurophysiological and radiological techniques have shed new light on the underlying pathophysiology. Also, it has been recognised that psychological dysfunction play an important role. However, there is a lack of consensus regarding what is abnormal, regarding the overlap between phenotypes and regarding optimal diagnostic approaches or tests. There has been little advance in drug therapy for these conditions. Although several treatments have been tried and appear promising, controlled trials are either lacking or have provided insignificant evidence. There is a need for improved medical, behavioural and surgical treatments for these conditions.

Effects of transanal pelvic plexus stimulation on penile erection: clinical implications

OBJECTIVE

To determine the ability of transanal pelvic plexus stimulation (TPPS) in inducing penile tumescence in patients with non-neurogenic erectile dysfunction (ED) and to compare the erection degree with papaverine-induced erection.

PATIENTS AND METHODS

The cavernous electrical activity (CEA) in 21 men with non-neurogenic erectile dysfunction was measured during TPPS by electromyography of corpus cavernosum and the erection degree of penis (flaccid, semi-rigid, rigid) was noted. The stimulation amplitude was increased from 20 to 100 mA. All patients also underwent intracavernous papaverine injection and further CEA recordings were obtained.

RESULTS

Twelve and nine patients were diagnosed with vasculogenic (VED) and non-vasculogenic ED (NVED), respectively. TPSS led to a penile erectile response in 12 patients (57%), whereas papaverine injection caused erection in 16 (76.2%) patients. The mean baseline CEA (16.9 +/- 9.1 mV) did not change with TPPS, but papaverine significantly decreased the mean CEA to 12.3 +/- 4.9 mV (P < 0.001). CEA recordings of 16 (76.2%) patients revealed a significant decrease after papaverine injection, however seven (33.3%) patients showed significant CEA decrease in response to TPPS. Both TPPS and papaverine were observed to have a higher effect in patients with NVED in terms of inducing penile erection and decreasing CEA compared to their effects in patients with VED.

CONCLUSION

TPPS induces penile erection and decreases CEA for some extent, but to a lesser degree compared to papaverine. As further improvements are achieved in the methodology of TPPS, it may be a valuable method in the evaluation patients with erectile dysfunction.

Posterior sagittal anorectoplasty in anorectal anomalies: clinical, manometric and profilometric evaluation

CONTEXT AND OBJECTIVE

Anorectal malformations comprise a spectrum of anomalies that continue to be difficult to treat, even today. The aim was to evaluate the fecal continence of children who underwent posterior sagittal anorectoplasty due to anorectal malformations, via computerized anorectal manometry and profilometry.

DESIGN AND SETTING

Prospective study at Universidade Federal de São Paulo.

METHOD

82 patients (56.1% boys; 43.9% girls) of mean age 85.5 months were evaluated. They were divided into continent, partially continent and incontinent groups. Age, sex, manometric variables and profilometric parameters were studied. The results were statistically analyzed.

RESULTS

Among the 82 patients, 37.8% were continent, 25.6% were partially continent and 36.6% were incontinent. The overall mean resting pressure was 22 mmHg, and the means for the continent, partially continent and incontinent groups were, respectively, 30.7 mmHg, 23 mmHg and 14.7 mmHg. The overall mean pressure response to voluntary contraction was 56 mmHg, and the means for the groups were 65.4 mmHg, 55.8 mmHg and 46.6 mmHg, respectively. The rectosphincteric reflex was absent in 82.9% of the cases. In the profilometry analysis for all patients together, blue (20 to 50 mmHg) and yellow (50 to 80 mmHg) were predominant, and there was a similar distribution for the continent and partially continent patients. However, among the incontinent patients, green (< 20 mmHg) and blue prevailed.

CONCLUSIONS

Manometric and computerized profilometric analyses were an excellent method for postoperative evaluations on patients with intermediate and high anorectal anomalies, and for therapeutic planning.

Anorectal function problems after left hemicolectomy

BACKGROUND

The aim of this study was to evaluate the subjective anorectal function in patients with left hemicolectomy and to clarify the clinical factors influencing postoperative anorectal function problems.

MATERIALS AND METHODS

One hundred and twenty one patients who underwent left hemicolectomy from April 2002 to December 2003 were enrolled in this study and sent questionnaires concerning anorectal function. Left hemicolectomy in patients with cancer was performed by high ligation of the inferior mesenteric artery; in patients with diverticulitis or polyposis, the inferior mesenteric artery was cut just below the branch of the left colonic artery. One hundred patients replied to the questionnaire: 52 men and 48 women, aged 37 to 85, with a mean age of 66.6 years. Differences were analyzed for statistical significance by the Chi square test and by logistic regression.

RESULTS

Anorectal function problems was present in 33% of patients: female gender (P = 0.02), laparoscopic surgery (P = 0.04), and postoperative diarrhea (P = 0.04) had significant independent effects on anorectal function problems. Transient early fecal incontinence was observed in 16% of patients and laparoscopic surgery had significant independent effects on this problem (P = 0.04). Inability to discriminate between gas and stool, tenesmus, or urgency were present in 21%, 18%, and 17% of cases, respectively, and were independently associated respectively with laparoscopic surgery (P = 0.005) and postoperative diarrhea (P = 0.019) (P = 0.015).

CONCLUSION

In our study the following two issues were clarified: anorectal function problems are frequent after left hemicolectomy, and the laparoscopic technique is linked to poor postoperative anorectal function. The technical methods of high ligation of the inferior mesenteric artery could explain this result.

Ultrasound imaging of sacral reflexes

OBJECTIVES

To investigate the reliability of examination of the guarding reflex of the pelvic floor by dynamic perineal ultrasonography in children with bladder dysfunction and in controls.

METHODS

A total of 40 patients with nonneurogenic bladder/sphincter dyssynergia, 40 with spina bifida, and 40 controls underwent a dynamic ultrasound examination of the pelvic floor while coughing and while being tapped on the abdominal wall. The reflex action of the puborectal muscle in females, and the combined action of the puborectal muscle and external sphincter muscle in males, were recorded.

RESULTS

Of the 40 patients with nonneurogenic bladder/sphincter dyssynergia, 38 had a normal reflex action of the puborectal muscle during the abdominal tap and 36 had a normal reflex action when coughing. Two of these patients had unexplained underactive bladder syndrome and were using clean intermittent catheterization, and two could not be assessed because of hypermobility of the bladder neck when coughing but had a normal reaction during abdominal tapping. Of the 40 patients with spina bifida, none had puborectal activity during coughing and 5 had some puborectal activity during tapping. Of the 40 controls, 39 had normal reflex activity during both coughing and tapping.

CONCLUSIONS

The question of whether a child has nonneurogenic or neuropathic bladder/sphincter dysfunction is often difficult to answer on the basis of urodynamic studies alone. Dynamic perineal ultrasound recording of the S2-S4 reflex arches provides reliable additional information and is noninvasive to the patient.

The utility of pudendal nerve terminal motor latencies in idiopathic incontinence

PURPOSE

Pudendal nerve terminal motor latency testing has been used to test for pudendal neuropathy, but its value remains controversial. We sought to clarify the relationship of pudendal nerve terminal motor latency to sphincter pressure and level of continence in a cohort of patients with intact anal sphincters and normal pelvic floor anatomy.

METHODS

We reviewed 1,404 consecutive patients who were evaluated at our pelvic floor laboratory for fecal incontinence. From this group, 83 patients had intact anal sphincters on ultrasound and did not have internal or external rectal prolapse during defecography. These patients were evaluated by pudendal nerve terminal motor latency testing, a standardized questionnaire, and anorectal manometry, which measured resting and squeeze anal pressures. Incontinence scores were calculated by using the American Medical Systems Fecal Incontinence Score. Values were compared by using the Fisher's exact test and Wilcoxon's rank-sum test; and significance was assigned at the P < 0.05 level.

RESULTS

1) Using a 2.2-ms threshold, 28 percent of patients had prolonged pudendal nerve terminal motor latency unilaterally and 12 percent bilaterally. 2) At a 2.4-ms threshold, 18 percent of patients had prolonged pudendal nerve terminal motor latency unilaterally and 8 percent bilaterally. 3) Bilaterally prolonged pudendal nerve terminal motor latency was significantly associated with decreased maximum mean resting pressure and increased Fecal Incontinence Score, but not decreased maximum mean squeeze pressure, at both 2.2-ms and 2.4-ms thresholds. 4) Unilaterally prolonged pudendal nerve terminal motor latency was not associated with maximum mean resting pressure, maximum mean squeeze pressure, or fecal incontinence score at either threshold.

CONCLUSIONS

The majority of incontinent patients with intact sphincters have normal pudendal nerve terminal motor latency. Bilaterally but not unilaterally prolonged pudendal nerve terminal motor latency is associated with poorer function and physiology in the incontinent patient with an intact sphincter.

A review of the epidemiology and pathophysiology of pelvic floor dysfunction: do racial differences matter?

OBJECTIVE

To describe the current state of knowledge regarding etiology of pelvic floor dysfunction with special consideration to the effect of racial background on the epidemiology and pathophysiology of this disease.

METHODS

We performed a nonsystematic review of the literature to detail the current knowledge of the etiology of pelvic floor dysfunction. Additionally, we performed a systematic search of MEDLINE, Cinahl, and the Cochrane database for English-language articles registered from January 1, 1989, to June 31, 2003, that evaluated racial differences in the epidemiology and pathophysiology of pelvic floor dysfunction. We also reviewed the references of identified articles.

RESULTS

We identified 11 articles that examined the effect of racial background on stress urinary incontinence (SUI), urodynamic stress incontinence, and (or) pelvic organ prolapse. We identified 2 studies that measured the prevalence of subjective stress urinary incontinence. Six cross-sectional studies compared the prevalence of urodynamically confirmed SUI and (or) pelvic organ prolapse among different groups. White women had a higher risk of developing urodynamic stress incontinence. Three studies noted anatomical and physiological differences among the different groups.

CONCLUSIONS

Both quantitative and qualitative defects in collagen (endopelvic fascia) and compromised levator ani muscle function have been identified as important etiologic factors in the development of pelvic floor dysfunction. Parity, vaginal delivery, menopause, and aging have been most clearly associated with collagen defects and levator ani muscle dysfunction. The literature suggests that white women are at increased risk for SUI. At present, there is insufficient evidence to draw any conclusions regarding the role of racial differences in pelvic organ prolapse. It is possible that differences in prevalence rates for both SUI and pelvic organ prolapse may be attributed to inherent anatomical and physiological differences among racial groups.

Review article: Recent trends in diagnosis and treatment of faecal incontinence

The inability to control bowel discharge is not only common but extremely distressing. It has a negative impact on a patient's lifestyle, leads to a loss of self-esteem, social isolation and a diminished quality of life. Faecal incontinence is often due to multiple pathogenic mechanisms and rarely due to a single factor. Normal continence to stool is maintained by the structural and functional integrity of the anorectal unit. Consequently, disruption of the normal anatomy or physiology of the anorectal unit leads to faecal incontinence. Currently, several diagnostic tests are available that can provide an insight regarding the pathophysiology of faecal incontinence and thereby guide management. The treatment of faecal incontinence includes medical, surgical or behavioural approaches. Today, by using logical approach to management, it is possible to improve symptoms and bowel function in many of these patients.

Pathophysiology of adult fecal incontinence

Fecal incontinence occurs when the normal anatomy or physiology that maintains the structure and function of the anorectal unit is disrupted. Incontinence usually results from the interplay of multiple pathogenic mechanisms and is rarely attributable to a single factor. The internal anal sphincter (IAS) provides most of the resting anal pressure and is reinforced during voluntary squeeze by the external anal sphincter (EAS), the anal mucosal folds, and the anal endovascular cushions. Disruption or weakness of the EAS can cause urge-related or diarrhea-associated fecal incontinence. Damage to the endovascular cushions may produce a poor anal "seal" and an impaired anorectal sampling reflex. The ability of the rectum to perceive the presence of stool leads to the rectoanal contractile reflex response, an essential mechanism for maintaining continence. Pudendal neuropathy can diminish rectal sensation and lead to excessive accumulation of stool, causing fecal impaction, mega-rectum, and fecal overflow. The puborectalis muscle plays an integral role in maintaining the anorectal angle. Its nerve supply is independent of the sphincter, and its precise role in maintaining continence needs to be defined. Obstetric trauma, the most common cause of anal sphincter disruption, may involve the EAS, the IAS, and the pudendal nerves, singly or in combination. It remains unclear why most women who sustain obstetric injury in their 20s or 30s typically do not present with fecal incontinence until their 50s. There is a strong need for prospective, long-term studies of sphincter function in nulliparous and multiparous women.

Diagnostic testing in fecal incontinence

Fecal incontinence is a common problem that disproportionately affects women and the elderly and has a significant impact on the quality of life. Incontinence is often multifactorial. Anorectal manometry, anal endosonography, magnetic resonance imaging, pudendal nerve latency, and electromyography provide morphologic and physiologic assessments of the internal and external anal sphincters, rectal motor and sensory function, rectal compliance, and rectoanal reflexes. This information, in concert, provides clues to the pathophysiology of fecal incontinence and may help to guide medical, surgical, or biofeedback therapy. These tests have also been used to assess the effectiveness of the therapeutic modalities. No data are available on the cost-effectiveness of diagnostic testing in fecal incontinence. Newer techniques, including electrophysiologic testing and morphologic imaging of the anorectum, are being pursued.

The role of electrophysiology in the evaluation of incontinence and prolapse

PURPOSE OF REVIEW

Apart from histopathology, electrophysiological methods are the only tests to reveal neuromuscular involvement in the absence of gross anatomical lesions. They have played a major role in establishing the neuromuscular lesion due to vaginal delivery as a risk factor for incontinence and pelvic organ prolapse, but there is no consensus on the usefulness of different methods. It is timely to reevaluate their validity, and their role in urogynecology.

RECENT FINDINGS

The most important development is the move towards standardization of the diagnostic approach, based on computer assisted quantified techniques of concentric needle electromyography. Studies using less operator biased techniques have confirmed subtle pelvic floor muscle changes in parous women. Reports on usefulness of different tests as predictors of treatment outcome are controversial.

SUMMARY

Standardization of concentric needle electromyography strengthened the position of this test as practical and informative. Neuromuscular changes following vaginal delivery have been reconfirmed, but the usefulness of particular electrophysiological tests in the individual patient needs to be further researched. Valid clinical neurophysiological methods remain valuable as research tools for incontinence and prolapse pathophysiology.