Electrodiagnostic evaluation of fecal incontinence

Baiona's Consensus Statement for Fecal Incontinence. Spanish Association of Coloproctology

Faecal incontinence (FI) is a major health problem, both for individuals and for health systems. It is obvious that, for all these reasons, there is widespread concern for healing it or, at least, reducing as far as possible its numerous undesirable effects, in addition to the high costs it entails. There are different criteria for the diagnostic tests to be carried out and the same applies to the most appropriate treatment, among the numerous options that have proliferated in recent years, not always based on rigorous scientific evidence. For this reason, the Spanish Association of Coloproctology (AECP) proposed to draw up a consensus to serve as a guide for all health professionals interested in the problem, aware, however, that the therapeutic decision must be taken on an individual basis: patient characteristics/experience of the care team. For its development it was adopted the Nominal Group Technique methodology. The Levels of Evidence and Grades of Recommendation were established according to the criteria of the Oxford Centre for Evidence-Based Medicine. In addition, expert recommendations were added briefly to each of the items analysed.

Faecal incontinence-a comprehensive review

Introduction

Faecal incontinence (FI) is a distressing and often stigmatizing condition characterised as the recurrent involuntary passage of liquid or solid faeces. The reported prevalence of FI exhibits considerable variation, ranging from 7 to 15% in the general population, with higher rates reported among older adults and women. This review explores the pathophysiology mechanisms, the diagnostic modalities and the efficiency of treatment options up to date.

Methods

A review of the literature was conducted to identify the pathophysiological pathways, investigation and treatment modalities.

Result and discussion

This review provides an in-depth exploration of the intricate physiological processes that maintain continence in humans. It then guides the reader through a detailed examination of diagnostic procedures and a thorough analysis of the available treatment choices, including their associated success rates. This review is an ideal resource for individuals with a general medical background and colorectal surgeons who lack specialized knowledge in pelvic floor disorders, as it offers a comprehensive understanding of the mechanisms, diagnosis, and treatment of faecal incontinence (FI).

Pudendal Nerve Terminal Motor Latency Compared by Anorectal Manometry Diagnosing Fecal Incontinence: A Retrospective Study

OBJECTIVE

The aim of the study was to compare the clinical value of pudendal nerve terminal motor latency in fecal incontinence patients with that of another diagnostic test-anorectal manometry.

DESIGN

This study used a cross-sectional design. Medical records of fecal incontinence patients who underwent pudendal nerve terminal motor latency and anorectal manometry testing were reviewed. Greater than 2.4 ms of pudendal nerve terminal motor latency was determined to be abnormal. Anorectal manometry was performed using a station pull-through technique. Mean resting anal pressure, maximal resting anal pressure, mean squeezing anal pressure, and maximal squeezing anal pressure were investigated. For normal and abnormal pudendal nerve terminal motor latency groups, comparative analyses were performed on anorectal manometry results.

RESULTS

A total of 31 patients were included. Thirteen patients showed normal pudendal nerve terminal motor latency. For anorectal manometry results, there was no significant difference between normal and abnormal pudendal nerve terminal motor latency groups. Fourteen patients had diabetes mellitus. Subgroup analysis of the 14 diabetic patients showed no significant difference between normal and abnormal pudendal nerve terminal motor latency groups. For 17 nondiabetic patients, there was a significant difference between the groups with positive correlations with mean/maximal resting anal pressures.

CONCLUSIONS

Pudendal nerve terminal motor latency significantly correlates with anorectal manometry in fecal incontinence only in nondiabetic patients.

The Role of Pelvic Neurophysiology Testing in the Assessment of Patients with Voiding Dysfunction

Purpose of Review

The role of pelvic neurophysiology testing in the evaluation of patients with lower urinary tract (LUT) symptoms is explored in this review.

Recent Findings

Different neurophysiology tests such as sphincter EMG and pudendal somatosensory evoked potentials are useful in evaluating the sacral somatic afferent and efferent innervation. S2 and S3 dermatomal evoked potentials assess individual sacral roots and are feasible to perform using standard neurophysiology machines.

Summary

The innervation of the LUT has a substantial contribution from splanchnic and somatic nerves arising from the sacral segments. Pelvic neurophysiology tests, which assess somatic nerve functions, are therefore a useful tool in assessing sacral nerve functions in patients presenting with unexplained voiding dysfunction. In this review, the commonly performed neurophysiology studies that assess the S2, S3 and S4 sacral afferent and efferent pathways are outlined, and their clinical applications reviewed.

Assessing Anorectal Function in Constipation and Fecal Incontinence

Constipation and fecal incontinence are commonly encountered complaints in the gastrointestinal clinic. Assessment of anorectal function includes comprehensive history, rectal examination, and prospective stool diary or electronic App diary that accurately captures bowel symptoms, evaluation of severity, and quality of life of measure. Evaluation of a suspected patient with dyssynergic constipation includes anorectal manometry, balloon expulsion test, and defecography. Investigation of a suspected patient with fecal incontinence includes high-resolution anorectal manometry; anal ultrasound or MRI; and neurophysiology tests, such as translumbosacral anorectal magnetic stimulation or pudendal nerve latency. This article provides an approach to the assessment of anorectal function.

A Novel High-Density Electromyography Probe for Evaluating Anorectal Neurophysiology: Design, Human Feasibility Study, and Validation with Trans-Sacral Magnetic Stimulation

Fecal incontinence (FI) substantially impairs quality of life and imparts a major socioeconomic burden. Anal sphincter injury and possibly pudendal nerve damage are considered common causes, however, current clinical methods for evaluating their function remain suboptimal. Electromyography (EMG) and pudendal nerve terminal latencies have been applied with some success, but are not considered standard practice due to uncertain accuracy and clinical value. In this study we developed and applied a novel anorectal high-density (HD) EMG probe in humans and pigs to acquire quantitative electrophysiological metrics of the anorectum. In the human trial we assessed somatic pathways and showed that EMG amplitude was greater for tight voluntary squeezes than light voluntary squeezes (0.03 ± 0.02 mV vs. 0.05 ± 0.03 mV). In a porcine model we applied trans-sacral magnetic stimulation to evoke extrinsically activated involuntary pathways and the resulting motor evoked potentials (MEP) were captured using the HD-EMG probe. The mean MEP amplitude at 50% magnetic stimulation intensity output (MSO) was significantly lower that the MEP amplitude at 85, 95 and 100% MSO (1.52 ± 0.50 mV vs. 3.10 ± 0.60 mV). In conclusion, the use of HD-EMG probe in conjunction with trans-sacral magnetic stimulation, for spatiotemporal mapping of anorectal EMG and MEP activity is anticipated to achieve new insights into FI and could offer improved diagnostic and prognostic biomarkers for anorectal dysfunction.

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.

Pudendal nerve terminal motor latency testing does not provide useful information in guiding therapy for fecal incontinence

PURPOSE

Pudendal nerve terminal motor latency (PNTML) testing is a standard recommendation for the evaluation of fecal incontinence. Its role in guiding therapy for fecal incontinence has been previously questioned. The aim of this study was to evaluate the relationship between PNTML testing and anorectal dysfunction.

METHODS

This was a retrospective analysis of data collected prospectively from patients who presented to a pelvic floor disorder center from 2007 to 2015. The relationship between PNTML (normal versus delayed) and anorectal manometry, fecal incontinence severity, and fecal incontinence-related quality of life scores was assessed using the Wilcoxon-Mann-Whitney test.

RESULTS

Two hundred sixty-nine patients underwent PNTML testing, and 91.1% were female (N = 245) (median age 62.2 years). Normal PNTML was seen in 234 (87.0%) patients. Among 268 patients who underwent anorectal manometry, delayed PNTML was only significantly associated with median maximum anal squeeze pressure (P = 0.04). Delayed PNTML was not associated with a decrease in median fecal incontinence severity or fecal incontinence-related quality of life scores (N = 99).

CONCLUSIONS

PNTML was only associated with median maximum anal squeeze pressure, and it was not associated with patient-reported severity of symptoms of fecal incontinence, changes in quality of life attributable to fecal incontinence, median mean resting anal pressure, or median maximum resting anal pressure. PNTML testing may not be relevant to current therapeutic algorithms for fecal incontinence and its routine use should be questioned.

Physiological study of the anorectal reflex in patients with functional anorectal and defecation disorders

OBJECTIVE

Fecal incontinence (FI) and constipation can arise from a variety of alterations of anorectal function. This study aimed to investigate the components of the anorecal reflex in patients with these symptoms and to determine the functional significance of various physiological parameters.

METHODS

Altogether 21 healthy volunteers (controls) and 78 FI-predominant and 74 constipation-predominant patients were recruited and administered Wexner incontinence and constipation questionnaires. All participants underwent standardized anorectal physiology assessments.

RESULTS

Patients with passive FI had lower resting sphincter pressures than controls (38 cmH₂ O vs 87 cmH₂ O, P  < 0.05), while those with urge FI had lower squeeze pressures than controls (37 cmH₂ O vs 119 cmH₂ O, P  < 0.05). Patients with urge FI had lower maximal tolerable volumes (100 mL vs 166 mL, P  < 0.05). Patients with slow-transit constipation had elevated rectal electrosensitivity thresholds compared with controls (31.4 mA vs 20.2 mA, P  < 0.05), and rectal mucosal blood flow than patients with evacuation difficulty and controls (107 vs 162 flux units (FU) [evacuation difficulty] vs 169 FU [controls], P  < 0.05). Only patients with passive FI were associated with reflex abnormalities (prolonged recovery phase (1.2 ms vs 0.5 ms, P  < 0.05) and total duration of reflex (6.3 ms vs 4.3 ms, P  < 0.05).

CONCLUSIONS

Anorectal motor, sensory and reflex abnormalities are seen in distinct patterns in patients with FI and constipation. This would suggest distinct physiological differences that may predict the potential for different neuromodulation treatment and behavioral modalities in these conditions.

Do endoflip assessments of anal sphincter distensibility provide more information on patients with fecal incontinence than high-resolution anal manometry?

BACKGROUND

Anal manometry is the standard technique for evaluating anal sphincter function. However, the functional lumen imaging probe (EndoFLIP(®) ) can be used to measure sphincter distensibility during volume-controlled distensions. Our aims were (i) to assess anal distensibility in patients with fecal incontinence (FI) and in healthy subjects using the EndoFLIP(®) and (ii) to compare the results with anal pressures measured by 3D high-resolution manometry (3D-HRM) to determine whether the EndoFLIP(®) was more sensitive and specific for diagnosing FI than 3D-HRM.

METHODS

EndoFLIP(®) and 3D-HRM assessments of 34 female FI patients and 40 healthy female subjects were performed. Anal distensibility was measured as the median cross-sectional area at the narrowest point divided by the corresponding intra-bag pressure at rest and during peak voluntary contraction and was expressed in mm(2) /mmHg.

KEY RESULTS

A 40-mL anal distensibility index was selected for further comparisons as it provided the best discrimination between the FI patients and the healthy subjects. The index was significantly higher in the FI patients than in the healthy subjects at rest (p = 1.10(-4) ) and during voluntary contraction (p = 1.10(-4) ). The index at rest and during voluntary contraction appeared to be more appropriate than anal pressures for discriminating between FI patients and healthy subjects.

CONCLUSIONS & INFERENCES

The present study confirmed that FI is associated with an abnormally high distensibility index at rest and during voluntary contraction. The ability of the distensibility index to discriminate between FI patients and healthy subjects was significantly better than anal pressure.

Diagnosis and treatment of faecal incontinence: Consensus statement of the Italian Society of Colorectal Surgery and the Italian Association of Hospital Gastroenterologists

Faecal incontinence is a common and disturbing condition, which leads to impaired quality of life and huge social and economic costs. Although recent studies have identified novel diagnostic modalities and therapeutic options, the best diagnostic and therapeutic approach is not yet completely known and shared among experts in this field. The Italian Society of Colorectal Surgery and the Italian Association of Hospital Gastroenterologists selected a pool of experts to constitute a joint committee on the basis of their experience in treating pelvic floor disorders. The aim was to develop a position paper on the diagnostic and therapeutic aspects of faecal incontinence, to provide practical recommendations for a cost-effective diagnostic work-up and a tailored treatment strategy. The recommendations were defined and graded on the basis of levels of evidence in accordance with the criteria of the Oxford Centre for Evidence-Based Medicine, and were based on currently published scientific evidence. Each statement was drafted through constant communication and evaluation conducted both online and during face-to-face working meetings. A brief recommendation at the end of each paragraph allows clinicians to find concise responses to each diagnostic and therapeutic issue.

Anal sphincteric neurogenic injury in asymptomatic nulliparous women and fecal incontinence

While anal sphincter neurogenic injury documented by needle electromyography (EMG) has been implicated to cause fecal incontinence (FI), most studies have been uncontrolled. Normal values and the effects of age on anal sphincter motor unit potentials (MUP) are ill defined. The functional significance of anal sphincter neurogenic injury in FI is unclear. Anal pressures and EMG were assessed in 20 asymptomatic nulliparous women (age, 38 ± 5 yr; mean ± SE) and 20 women with FI (54 ± 3 yr). A computerized program quantified MUP duration and phases. These parameters and MUP recruitment were also semiquantitatively assessed by experienced electromyographers in real time. Increasing age was associated with longer and more polyphasic MUP in nulliparous women by quantitative analysis. A higher proportion of FI patients had prolonged (1 control, 7 patients, P = 0.04) and polyphasic MUP (2 controls, 9 patients, P = 0.03) at rest but not during squeeze. Semiquantitative analyses identified neurogenic or muscle injury in the anal sphincter (11 patients) and other lumbosacral muscles (4 patients). There was substantial agreement between quantitative and semiquantitative analyses (κ statistic 0.63 ± 95% CI: 0.32-0.96). Anal resting and squeeze pressures were lower (P ≤ 0.01) in FI than controls. Anal sphincter neurogenic or muscle injury assessed by needle EMG was associated (P = 0.01) with weaker squeeze pressures (83 ± 10 mmHg vs. 154 ± 30 mmHg) and explained 19% (P = 0.01) of the variation in squeeze pressure. Anal sphincter MUP are longer and more polyphasic in older than younger nulliparous women. Women with FI have more severe neurogenic or muscle anal sphincter injury, which is associated with lower squeeze pressures.

Laparoscopic management of persistent complete rectal prolapse in children

BACKGROUND

Rectal prolapse is a relatively common condition in children. The multiplicity of surgical approaches used for rectal prolapse indicates that there is no single approach universally accepted and applicable to all cases. The laparoscopic approach promises to become the criterion standard for the management of full-thickness rectal prolapse in children. The aim of this study was to review our experience over the last 5 years and to evaluate the results that can be achieved by using laparoscopy in management of complete rectal prolapse in children.

PATIENTS AND METHODS

Forty patients presented with complete rectal prolapse and fecal incontinence grades (3-4) according to Rintala scale (37 secondary to prolapse and 3 neuropathic) had been operated upon laparoscopically from August 2003 to August 2008. They were subjected to clinical examination, investigations, pre- and postoperative electromyogram activities for external sphincter, puborectalis, and pelvic floor muscles. The pathophysiologic changes for each case was identified and dealt with laparoscopically (laparoscopic suture rectopexy, laparoscopic mesh rectopexy, laparoscopic resection rectopexy, and laparoscopic levatorplasty).

RESULTS

Among the 40 children with complete rectal prolapse, 22 were males and 18 females. Their median age was 9 years (range, 4-14 years). All cases (n = 40) showed a redundant rectosigmoid junction. Additional laxity of the pelvic floor was present in 32, rectoanal intussusception in 27, anterior wall rectoanal intussusception in 3, and rectosacral hernia in 5 cases. All procedures were completed laparoscopically. The median duration of surgery was 60 minutes (range, 50-70 minutes) for suture rectopexy, 90 minutes (range, 60-110 minutes) for mesh rectopexy, 110 minutes (range, 95-160 minutes) for resection rectopexy, and 120 minutes (range, 100-150 minutes) for laparoscopic levatorplasty. No intraoperative complications occurred in this study. Median postoperative hospitalization was 3 days (range, 2-5 days). Electromyogram studies showed statistically significant improvement during rest, minimal volition, and squeezing in all cases except those children with spina bifida and meningomyelocele. The only complications were postoperative constipation and external colonic fistula. Significant improvement of the continence score was achieved in all cases. The average follow-up time was 36 months. There were no recurrences.

CONCLUSION

The use of laparoscopy in the management of complete rectal prolapse is safe, effective, and associated with improved functional outcome. It saved the patients multiple operations and is associated with minimal postoperative pain and short hospital stay.

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.

Neurophysiological testing in anorectal disorders

Neurophysiological tests of anorectal function can provide useful information regarding the integrity of neuronal innervation, as well as neuromuscular function. This information can give insights regarding the pathophysiological mechanisms that lead to several disorders of anorectal function, particularly fecal incontinence, pelvic floor disorders and dyssynergic defecation. Currently, several tests are available for the neurophysiological evaluation of anorectal function. These tests are mostly performed on patients referred to tertiary care centers, either following negative evaluations or when there is lack of response to conventional therapy. Judicious use of these tests can reveal significant and new understanding of the underlying mechanism(s) that could pave the way for better management of these disorders. In addition, these techniques are complementary to other modalities of investigation, such as pelvic floor imaging. The most commonly performed neurophysiological tests, along with their indications and clinical utility are discussed. Several novel techniques are evolving that may reveal new information on brain-gut interactions.

Neurophysiological testing in anorectal disorders

The neurophysiological techniques currently available to evaluate anorectal disorders include concentric needle electromyography (EMG) of the external anal sphincter, anal nerve terminal motor latency (TML) measurement in response to transrectal electrical stimulation or sacral magnetic stimulation, motor evoked potentials (MEPs) of the anal sphincter to transcranial magnetic cortical stimulation, cortical recording of somatosensory evoked potentials (SEPs) to anal nerve stimulation, quantification of electrical or thermal sensory thresholds (QSTs) within the anal canal, sacral anal reflex (SAR) latency measurement in response to pudendal nerve or perianal stimulation, and perianal recording of sympathetic skin responses (SSRs). In most cases, a comprehensive approach using several tests is helpful for diagnosis: needle EMG signs of sphincter denervation or prolonged TML give evidence for anal motor nerve lesion; SEP/QST or SSR abnormalities can suggest sensory or autonomic neuropathy; and in the absence of peripheral nerve disorder, MEPs, SEPs, SSRs, and SARs can assist in demonstrating and localizing spinal or supraspinal disease. Such techniques are complementary to other methods of investigation, such as pelvic floor imaging and anorectal manometry, to establish the diagnosis and guide therapeutic management of neurogenic anorectal disorders.

Electrophysiologic studies and clinical findings in females with combined fecal and urinary incontinence: a prospective study

PURPOSE

Several clinical, urodynamic, and manometric findings suggest neurologic damage as a contributing factor in the development of combined fecal and urinary incontinence. In this study, we wanted to test the hypothesis of pudendal nerve neuropathy being a more frequent lesion in patients with double incontinence compared with patients with isolated fecal incontinence.

PATIENTS

Ninety-three females with combined fecal and urinary incontinence and 36 females with isolated fecal incontinence were investigated. All patients underwent anal manometry, endoanal ultrasound, electromyography, and pudendal nerve terminal motor latency.

RESULTS

No statistically significant differences were found in the age, history of vaginal delivery, and chronic straining between both groups. However, the rate of postmenopausal females was higher in the combined fecal and urinary incontinence group (85 vs. 67 percent; P = 0.02). Menopause was an independent risk factor of having double incontinence (odds ratio, 1.4; P = 0.02). Concentric needle electromyography of the external anal sphincter revealed increased duration of the motor unit potentials in 43 and 53 percent of patients with combined fecal and urinary incontinence and isolated fecal incontinence, respectively (P = 0.28). An increased number of polyphasic motor unit potentials was detected in 52 and 58 percent (P = 0.6). There was no statistically significant difference in the prevalence of bilateral (20 vs. 27 percent) or unilateral (23 vs. 14 percent) prolonged mean pudendal nerve terminal motor latency between both groups (P = 0.3).

CONCLUSIONS

Pudendal neuropathy is not a distinct characteristic of patients with double incontinence. The prevalence of pudendal neuropathy in these patients is similar to that observed in patients with isolated fecal incontinence. Others factors should be investigated to explain the common association of both types of incontinence.

The etiology, assessment, and treatment of fecal incontinence

Fecal incontinence is a common symptom that often impairs quality of life. It is generally caused by a variety of conditions that are associated with anorectal sensorimotor dysfunction and/or diarrhea. Assessment should be tailored to age and symptom severity. Modulation of disordered bowel habits is the key to management; biofeedback and surgery might also be beneficial.

Fecal incontinence related to pregnancy

Fecal incontinence related to pregnancy is an underreported and debilitating physical problem that has psychosocial ramifications. Disruption of the external and internal anal sphincters, which may occur during vaginal delivery, is the most common etiologic factor. Endoanal ultrasound is a minimally invasive, simple, and accurate diagnostic tool used to confirm and guide management of sphincter complex disruption.

Outcome measures for fecal incontinence: anorectal structure and function

Fecal incontinence is a symptom attributable to a variety of disorders affecting one or more factors that maintain continence. Objective assessments should complement symptom assessments as outcome measures in therapeutic trials; conceivably, these assessments may also predict the response to therapy. Consistent with existing trends, most therapeutic trials should incorporate anal sphincter pressures and rectal sensation as outcome variables, paying meticulous attention to techniques. Rectal sensation is increased after pelvic floor retraining by biofeedback therapy in fecal incontinence; however, the predictive value of improved anal pressures after biofeedback has not been clearly established. Other factors maintaining continence can be assessed by newer approaches. In addition to assessing rectal sensation, a barostat also measures rectal compliance; alterations in rectal compliance modulate rectal perception. Particularly appropriate end points for trials involving surgical repair are sphincter integrity, assessed by endoanal ultrasound or magnetic resonance imaging (MRI), and puborectalis and pelvic floor motion, assessed by dynamic MRI. Despite disagreement about which technique is superior for evaluating the internal sphincter, MRI performs the same or better than ultrasound for assessing the external sphincter. The utility of measuring pudendal nerve latencies as a marker of pudendal nerve injury is limited; needle electromyography provides a sensitive measure of denervation and can usually identify myopathic damage, neurogenic damage, or mixed injury. These standardized, reproducible assessments of the multifaceted mechanisms maintaining fecal incontinence should be incorporated as outcome variables in therapeutic trials of fecal incontinence.

Reference values of motor unit potentials (MUPs) of the external anal sphincter muscle

OBJECTIVE

To provide reference values for the isolated motor unit potentials (MUPs) in the external anal sphincter (EAS) muscle, as mean duration, mean amplitude, mean area, number of turns and number of phases, related to the age of the patient. These data are not available in worldwide literature in spite of the fact that the EAS muscle is being increasingly mentioned in relation to differential diagnosis.

METHODS

Study of 235 subjects aged 0-80 years using an automated analysis program.

RESULTS

The study performed shows a clear gradual progression of the mean duration with patient age. The variability of all other parameters tested is also analyzed.

CONCLUSIONS

Our study shows that the classical values of MUPs isolated in the EAS muscle are directly related to age, and that this method is fully reliable to study its pathological conditions.

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.

Respective value of pudendal nerve terminal motor latency and anal sphincter electromyography in neurogenic fecal incontinence

Fecal incontinence may be related to a neurogenic injury. Electrodiagnostic tests including pudendal nerve terminal motor latency (PNTML) and external anal sphincter electromyography (AEMG) have been proposed to reveal anal nerve damage. The aim of this study was to assess the respective value of PNTML and AEMG in the diagnosis of fecal incontinence. This study included 80 women (range 23-85 years) with fecal incontinence secondary to obstetrical and/or surgical trauma. They were evaluated by performing PNTML and AEMG. The electrophysiological results were compared and interpreted in the light of anorectal manometry (ARM) results. Electrodiagnostic test abnormalities were found in 64 of 80 patients (80%), including 28 patients with abnormal results for both tests and 36 patients with only one abnormal test. Overall, a neurogenic AEMG pattern was found in 64% of patients and a prolonged PNTML in 51%. No correlation was found between PNTML value and either AEMG grade or ARM parameters, while AEMG grade strongly correlated with squeeze pressure measured by ARM. This study showed that AEMG and PNTML did not give redundant information and allowed to explicit the mechanisms of neurogenic fecal incontinence. We found that AEMG was more sensitive and more closely related to the anal functional status (ARM parameters) than PNTML. These electrodiagnostic tests, particularly AEMG as performed in everyday practice, are useful in the assessment of neurogenic fecal incontinence.

Investigation of faecal incontinence

Most patients with faecal incontinence require only a full history (information about other predisposing causes) and examination (assessment for faecal impaction and evaluation of sphincter function and structure). When necessary, anorectal physiological studies, endoanal ultrasound and magnetic resonance imaging allow accurate characterization of sphincter function and structure.

Clinical neurophysiology and electrodiagnostic testing of the pelvic floor

This article summarizes our current understanding of the neuroanatomy and neurophysiology of the pelvic floor. The electrodiagnostic evaluation of the pelvic floor muscles and external anal sphincter, including pudendal nerve conduction studies, sacral reflexes, and needs EMG is presented. The discussion reviews the test methodology, the strengths and limitations of each test, and their clinical utility. The authors have tried to critically review the objective evidence to support the use of electrodiagnostic tests in the evaluation and management of pelvic floor disorders. The reader will have a better understanding of the rationale, methodology, clinical utility, and potential pitfalls for each of the commonly used neurophysiological tests of the pelvic floor.

Pudendal nerve terminal motor latency: age effects and technical considerations

OBJECTIVES

The measurement of the pudendal nerve terminal motor latency (PNTML) is used to assess anal sphincter innervation. In healthy subjects, we studied the influence of age on PNTML and the advantage of a new intra-rectal stimulator.

METHODS

PNTML was determined in a first series of 40 normal subjects, aged 21-75 years, using a standard St. Mark's electrode, and in a second series of 20 normal subjects over 50 years, using a new intra-rectal monopolar stimulator that did not require finger insertion through the anal canal.

RESULTS

In the first series, PNTML ranged from 1.8 to 5.6 ms (mean+/-SD 2.94+/-0.8 ms) and correlated positively with the age of the subjects (P=0.01, Spearman test). In the second series, PNTML ranged from 2.2 to 5.4 ms (3.7+/-0.9 ms) and was similar to that of the subjects over 50 years of the first series (3.5+/-0.4 ms) (P=0.35, Mann-Whitney U test).

CONCLUSIONS

This study showed significant effects of age on PNTML. This should encourage every examiner to establish age-stratified reference values of PNTML for older age groups. In addition, we showed the advantage of using a new type of intra-rectal stimulator to reduce the patient's discomfort by avoiding finger insertion to stimulate the pudendal nerve.

Evaluation of the sacroanal motor pathway by magnetic and electric stimulation in patients with fecal incontinence

PURPOSE

The aim of this controlled study was to examine whether it was feasible to use magnetic stimulation as a new diagnostic tool to evaluate the motor function of the sacral roots and the pudendal nerves in patients with fecal incontinence.

PATIENTS AND METHODS

Nineteen consecutive patients (17 females) with a median age of 67 (range, 36-78) years referred for fecal incontinence and 14 healthy volunteers (six females) with a median age of 42 (range, 23-69) years were examined. Latency times of the motor response of the external anal sphincter were measured after electric transrectal stimulation of the pudendal nerve and magnetic stimulation of the sacral roots.

RESULTS

The success rates of pudendal nerve terminal motor latency and sacral root terminal motor latency measurements were 100 and 85 percent, respectively, in the control group and 94 and 81 percent, respectively, in the fecal incontinence group. Median left pudendal nerve terminal motor latency was 1.88 (range, 1.4-2.9) milliseconds in the control group and 2.3 (range, 1.8-4) milliseconds in the fecal incontinence group (P < 0.006). Median right pudendal nerve terminal motor latency was 1.7 (range, 1.3-3.4) milliseconds in the control group and 2.5 (range, 1.7-6) milliseconds in the fecal incontinence group (P < 0.003). Median left sacral root terminal motor latency was 3.3 (range, 2.1-6) milliseconds in the control group and 3.7 (range, 2.8-4.8) milliseconds in the fecal incontinence group (P < 0.03). Median right sacral root terminal motor latency was 3 (range, 2.6-5.8) milliseconds in the control group and 3.9 (range, 2.5-7.2) milliseconds in the fecal incontinence group (P = 0.15).

CONCLUSIONS

Combined pudendal nerve terminal motor latency and sacral root terminal motor latency measurements may allow us to study both proximal and distal pudendal nerve motor function in patients with fecal incontinence. Values of sacral root terminal motor latency have to be interpreted cautiously because of the uncertainty about the exact site of magnetic stimulation and the limited magnetic field strength.

Treatment options for fecal incontinence

PURPOSE

Fecal incontinence is a socially devastating disorder which affects at least 2.2 percent of community dwelling adults and 45 percent of nursing home residents. Most incontinent patients can be helped, but physicians are poorly informed about treatment options. The aim of this study was to develop a consensus on treatment options by convening a conference of surgeons, gastroenterologists, nurses, psychologists, and patient advocates.

METHOD

A 1-1/2 day conference was held in April, 1999. Experts from different disciplines gave overviews, followed by extended discussions. Consensus statements were developed at the end of the conference. This summary statement was drafted, circulated to all participants, and revised based on their input.

CONCLUSIONS

1) Diarrhea is the most common aggravating factor for fecal incontinence, and antidiarrheal medications such as loperamide and diphenoxylate or bile acid binders may help. Fecal impaction, a common cause of fecal incontinence in children and elderly patients, responds to combinations of laxatives, education, and habit training in approximately 60 percent. These causes of fecal incontinence can usually be identified by history and physical examination alone. 2) In patients who fail medical management or have evidence of sphincter weakness, anorectal manometry and endoanal ultrasound are recommended as helpful in differentiating simple morphologic defects from afferent and efferent nerve injuries and from combined structural and neurologic injuries. 3) Biofeedback is a harmless and inexpensive treatment which benefits approximately 75 percent of patients but cures only about 50 percent. It may be most appropriate when there is neurologic injury (i.e., partial denervation), but it has been reported to also benefit incontinent patients with minor structural defects. 4) External anal sphincter plication with or without pelvic floor repair is indicated when there is a known, repairable structural defect without significant neurologic injury. It is effective in approximately 68 percent. 5) Salvage operations are reserved for patients who can not benefit from biofeedback or levator-sphincteroplasty. These include electrically stimulated gracilis muscle transpositions and colostomy. 6) Antegrade enemas delivered through stomas in the cecum or descending colon reduce or eliminate soiling in approximately 78 percent of children with myelomeningocele; this operation may come to be more widely applied. 7) Investigational treatments include implanted nerve stimulators, artificial sphincters, and anal plugs. 8) Patient characteristics which influence choice of treatment include mental status, mobility impairment, and typical bowel habits. 9) Additional research is needed to better define the mechanisms responsible for fecal incontinence, to assess the efficacy of these treatments, to develop better treatments for nursing home residents, and to identify predictors of outcome.

Standardization of anal sphincter electromyography: normative data

OBJECTIVES

Electromyography (EMG) of the external anal sphincter (EAS) is important in the evaluation of conus/cauda lesions, the differential diagnosis of parkinsonism and anal incontinence. The aim of our study was to establish normative data in a sufficiently large group of healthy subjects, using a rigorously standardized examination technique.

METHODS

Sixty-four subjects (aged 19-83 years) without pelvic or neurological disorders were included. Motor unit potentials (MUPs)/interference pattern (IP) samples were obtained from the EAS using multi-MUP and turn/amplitude analyses, respectively. The effect of age, gender, parity, and constipation on MUP/IP parameters was studied. For MUP parameters the lower/upper limits for mean values, and 'outlier' limits, and for IP parameters normal 'clouds' were calculated.

RESULTS

From 112 muscles 15-30 MUPs were sampled. As no effect of evaluated factors on mean values could be demonstrated, common reference values were calculated. Lower/higher limits for mean values were: amplitude 148/661 microV, duration 3.2/7.8 ms, area 87/625 microVms, and number of phases 2. 3/3.7. 'Outlier' limits for individual MUPs were: amplitude 84/1315 microV, duration 1.6/13.8 ms, area 46/1222 microVms, number of phases 2/6. From 95 muscles 2706 IP samples were obtained.

CONCLUSIONS

The presented normative data should allow valid quantitative EMG of the EAS muscle in patients.

Delayed pudendal nerve conduction and endosonographic appearance of the anal sphincter complex

PURPOSE

The aim of this study was to test the hypothesis that a delay in pudendal nerve conduction as measured by pudendal nerve terminal motor latency should be associated with atrophy of the external anal sphincter as measured using endoanal ultrasound.

METHODS

Sixty-two adult females (median age, 58.9 (range, 22-88) years) presenting for evaluation of fecal incontinence with no evidence of an external anal sphincter tear on ultrasound were recruited. Ultrasound was performed with a 7.5-MHz radial rotating axial endoprobe in the left lateral position. Four measurements were made in the transverse plane--the external anal sphincter thickness in the midanal canal at the 6 o'clock and 9 o'clock positions, the internal sphincter at the 9 o'clock position, and the external anal sphincter in the low canal at the 9 o'clock position. Pudendal nerve terminal motor latency was measured using a transrectal nerve stimulation technique with measurement of the evoked muscle response.

RESULTS

Although there was a trend toward thinner external sphincter muscles in those with bilateral prolonged pudendal nerve terminal motor latency, independent sample t-tests and Pearson correlation coefficients showed no statistically significant relationship (right pudendal nerve terminal motor latency: P = 0.083, 0.184, 0.128, 0.910; r = 0.228, 0.175, -0.201, -0.015; left pudendal nerve terminal motor latency: P = 0.946, 0.276, 0.510, 0.123; r = -0.009, -0.143, -0.087, -0.201).

CONCLUSIONS

No statistically significant relationship between ultrasound-measured anal sphincter muscle thickness and pudendal nerve terminal motor latency was identified. Although a trend was suggested that could be further evaluated by a study with a larger sample size and a control group with asymptomatic patients, the small differences in muscle thickness involved and the difficulties in measurement suggest that the establishment of clinically useful ultrasound criteria for the detection of the neuropathic anal sphincter complex is unlikely.

Long-term results of electromyographic biofeedback training for fecal incontinence

PURPOSE

The aim of this study was to examine the long-term results of electromyographic biofeedback training in fecal incontinence.

METHODS

Thirty-seven patients (1 male) received a customised program of 2 to 11 (median, 3) biofeedback training sessions with an anal plug electromyometer. Nine patients had persistent incontinence after anal sphincter repair, a further 8 patients had postsurgical or partial obstetric damage of the sphincter but no sphincter repair, 9 patients had neurogenic sphincter damage, and 11 patients were classified as having idiopathic fecal incontinence. Duration of voluntary sphincter contraction was measured by anal electromyography (endurance score) before and after treatment. A postal questionnaire was used to investigate the following variables: 1) subjective rating on a four-grade Likert-scale of the overall result of the biofeedback training; 2) incontinence score (maximum score is 18, and 0 indicates no incontinence); and 3) rating of bowel dissatisfaction using a visual analog scale (0 to 10).

RESULTS

Twenty-two patients (60 percent) rated the result as very good (n = 8) or good (n = 14) immediately after the treatment period. Median endurance score improved from 1 to 2 minutes (P < 0.0001). Median incontinence score improved from 11 to 7, and bowel dissatisfaction rating improved from 5 to 2.8 (both P < 0.0001). After a median follow-up of 44 (range, 12-59) months, 15 patients (41 percent) still rated the overall result as very good (n = 3) or good (n = 12). The incontinence score did not change during follow-up. Median bowel dissatisfaction rating deteriorated from 2.8 to 4.2 but remained better than before treatment. Poor early subjective rating and the need for more than three biofeedback sessions were predictive of worsening during follow-up.

CONCLUSION

We think it is encouraging that in this study biofeedback treatment for fecal incontinence with an intra-anal plug electrode resulted in a long-term success rate in nearly one-half of the patients.

Recurrent rectal prolapse: what is the next good option?

PURPOSE

The aim of this study was to assess the clinical and functional outcome of surgery for recurrent rectal prolapse and compare it with the outcome of patients who underwent primary operation for rectal prolapse.

METHODS

All patients who underwent surgery for rectal prolapse were evaluated for age, gender, procedure, anorectal manometry and electromyography findings, and morbidity. The results for patients who underwent surgery for recurrent rectal prolapse were compared with a group of patients matched for age, gender, surgeon, and procedure who underwent primary operations for rectal prolapse.

RESULTS

A total of 115 patients underwent surgery for rectal prolapse. Twenty-seven patients, 10 initially operated on at this institution and 17 operated on elsewhere, underwent surgery for recurrent rectal prolapse. These 27 patients were compared with 27 patients with primary rectal prolapse operated on in our department. In the recurrent rectal prolapse group, prior surgery included rectopexy in 7 patients, Delorme's procedure in 7 patients, perineal rectosigmoidectomy in 7 patients, anal encirclement procedure in 4 patients, and resection rectopexy in 2 patients. Operations performed for recurrence were perineal rectosigmoidectomy in 14 patients, resection rectopexy in 8 patients, rectopexy in 2 patients, pelvic floor repair in 2 patients, and Delorme's procedure in 1 patient. There were no statistically significant differences between the groups in preoperative incontinence score (recurrent rectal prolapse, 13.6 +/- 7.8 vs. rectal prolapse, 12.7 +/- 7.2; range, 0-20) or manometric or electromyography findings, and there were no significant differences in mortality (0 vs. 3.7 percent), mean hospital stay (5.4 +/- 2.5 vs. 6.9 +/- 2.8 days), anastomotic complications (anastomotic stricture (0 vs. 7.4 percent), anastomotic leak (3.7 vs. 3.7 percent) and wound infection (3.7 vs. 0 percent), postoperative incontinence score (2.8 +/- 4.8 vs. 1.5 +/- 2.7), or recurrence rate (14.8 vs. 11.1 percent) between the two groups at a mean follow-up of 23.9 (range, 6-68) and 22 (range, 5-55) months, respectively. The overall success rate for recurrent rectal prolapse was 85.2 percent.

CONCLUSION

The outcome of surgery for rectal prolapse is similar in cases of primary or recurrent prolapse. The same surgical options are valid in both scenarios.

Results of neurophysiologic evaluation in fecal incontinence

PURPOSE

Several methods of neurophysiologic assessment exist in the investigation of patients with fecal incontinence. However, the clinical significance of the information gained is uncertain. The aim of this prospective study was to evaluate the results of pudendal nerve terminal motor latency and fiber density in relation to clinical variables and manometric measurements.

METHODS

Seventy-two patients with fecal incontinence (63 women; mean age, 62; range, 24-81 years) responded to a bowel questionnaire and underwent anorectal manovolumetry, anal ultrasonography, defecography, and electromyography, including pudendal nerve terminal motor latency and fiber density.

RESULTS

Pudendal neuropathy (pudendal nerve terminal motor latency > 2.5 ms) was found in 46 percent and increased fiber density (> 1.7) in 82 percent. Pudendal neuropathy and increased fiber density were most common in patients with rectal prolapse or intra-anal intussusception. No difference was seen concerning anal resting and incremental pressures, rectal compliance, rectal sensibility or severity of incontinence in patients with unilateral, bilateral, or marked (> 4 ms) pudendal neuropathy vs. patients with normal pudendal nerve terminal motor latency. In contrast, patients with increased fiber density had lower incremental pressures (P < 0.05) and stated decreased rectal sensibility (P < 0.05) compared with those with normal fiber density. These differences were most pronounced in patients with neurogenic or idiopathic incontinence.

CONCLUSIONS

Pudendal neuropathy and increased fiber density are common in patients with fecal incontinence. Fiber density but not pudendal nerve terminal motor latency was correlated with clinical and manometric variables. The severity of nerve injury correlated with anal motor and sensory function in patients with neurogenic or idiopathic incontinence. The routine use of pudendal nerve terminal motor latency in the assessment of patients with fecal incontinence can be questioned.

AGA technical review on anorectal testing techniques

This literature review and the recommendations therein were prepared for the American Gastroenterological Association Clinical Practice and Practice Economics Committee. Following external review, the paper was approved by the committee on May 17, 1998.

Pudendal neuropathy is predictive of failure following anterior overlapping sphincteroplasty

PURPOSE

This study assessed the efficacy of anterior overlapping sphincteroplasty and parameters predictive of a successful outcome.

METHODS

Clinical findings and physiologic investigations of female patients who underwent anterior overlapping sphincteroplasty for fecal incontinence between 1988 and 1996 were reviewed. The extent of sphincter damage was assessed at needle electromyography as the number of quadrants exhibiting decreased motor unit potentials. Prolonged pudendal nerve terminal motor latencies were those of greater than 2.2 ms. The size of the endoanal ultrasound defect was assessed as degrees circumference of the external sphincter in which viable muscle was absent. Patients were reviewed by telephone questionnaire and were asked to grade the outcome of their surgery as excellent or good (success) or fair or poor (failure). Incontinence was graded using a scoring system of 0 (perfect continence) to 20 (complete incontinence).

RESULTS

There were 100 patients who had an overlapping sphincteroplasty; complete follow-tip information was obtained for 77 patients at a median of 24 (range, 2-96) months. The median age was 47 (range, 25-80) years and they had a median duration of incontinence of four (range, 0.1-39) years. Prior sphincteroplasty had been performed in 30 patients with a median of one (range, 1-7) operations. Investigations performed included electromyography (n = 49), pudendal nerve terminal motor latency (n = 71), endoanal ultrasound (n = 49), and manometry (n = 67). Sixty percent of patients had improved continence and 42 (55 percent) considered their surgery to have been successful as attested to by a significant decrease in their incontinence score (from 15.1 +/- 4.5 to 4.3 +/- 4.2; P < 0.0001). Neither patient age, parity, prior sphincteroplasty, cause or duration of incontinence, extent of electromyography damage, size of the endoanal ultrasound defect, nor any manometric parameter correlated with outcome. However, 62 percent of 59 patients with bilaterally normal pudendal nerve terminal motor latencies had a successful outcome compared with only 16.7 percent of 12 patients with unilateral or bilateral prolonged pudendal nerve terminal motor latencies (P < 0.01).

CONCLUSION

Bilateral normal pudendal nerve terminal motor latencies are the only factors predictive of long-term success after overlapping sphincteroplasty.

Preoperative electrophysiologic assessment cannot predict continence after rectopexy

PURPOSE

The aim of this study was to evaluate preoperative electrophysiologic assessment for prediction of anal continence after rectopexy.

METHODS

Forty-three patients with rectal prolapse (n = 26) or internal rectal intussusception (n = 17) underwent concentric-needle electromyography, fiber density determination by single-fiber electromyography of the external anal sphincter, and pudendal nerve terminal motor latency evaluation before Ripstein rectopexy. A detailed history was obtained from each patient preoperatively and postoperatively.

RESULTS

Anal continence was improved after rectopexy, both in patients with rectal prolapse (P = 0.06) and in those with internal rectal intussusception (P = 0.003). Abnormal results were registered in one or several aspects of the electrophysiologic assessment in 31 (72 percent) of the patients. However, functional outcome with respect to continence was not predicted by preoperative electromyography or pudendal nerve terminal motor latency assessment results.

CONCLUSION

Electrophysiologic examinations in the preoperative assessment of patients with rectal prolapse and internal rectal intussusception do not predict continence after the Ripstein rectopexy. The routine use of electrophysiologic assessment requires further definition.

A clinical approach to fecal incontinence

Fecal incontinence is the impaired ability to control gas or stool. It is a disabling and distressing condition. Its exact incidence and prevalence are unknown. It is a disorder about which patients are frequently reluctant to discuss, even with their physician. However, it is a common condition especially in older individuals, where the prevalence has been reported to approach 60%. In women, incontinence reaches 54% as a result of childbirth. Of the patients surgically treated, the female-to-male ratio is 4 to 1. In an epidemiological study to identify its community-based prevalence, the University of Illinois determined fecal incontinence existed in 2.2% of the general population. There is available treatment for fecal incontinence. Many patients improve with conservative treatment (constipating agents, antidiarrheal medications, dietary changes) or with biofeedback. For patients where conservative treatment has failed, surgical treatment (direct-apposition sphincter repair, overlapping sphincteroplasty, postanal repair, neosphincter procedures) may be successful.

Parameters of the rectoanal inhibitory reflex in patients with idiopathic fecal incontinence and chronic constipation

PURPOSE

The rectoanal inhibitory reflex is a response of the internal anal sphincter to rectal distention, reflecting the functional nature of the anal sampling mechanism of rectal discrimination. The aim of this study was to assess the parameters of the rectoanal inhibitory reflex in healthy volunteers and incontinent and symptomatically constipated patients.

METHODS

The rectoanal inhibitory reflex was recorded in 42 patients using reproducible threshold volumes. Excitatory and inhibitory latencies, maximum excitatory and inhibitory pressures, amplitude, and slope of inhibition, slope and time of pressure recovery, and area under the inhibitory curve were estimated. Pudendal nerve terminal motor latency and endoanal magnetic resonance imaging were performed in all incontinent patients.

RESULTS

Significant linear trends were found for most parameters at each sphincter level when analyzed. Recovery time and area under the inhibitory curve differed between the sphincter levels and patient groups, with the most rapid recovery occurring in the distal sphincter of incontinent patients (P < 0.001). These pressure findings were not accounted for by differences in excitation between patient groups.

CONCLUSION

A coordinated response by the internal anal sphincter to rectal distention with recovery of anal pressure from the distal to the proximal sphincter is suggested. Continence may rely on the character of internal anal sphincter inhibition, and recovery and preoperative assessment of rectoanal inhibitory reflex parameters may be important for predicting functional result following low anastomosis.

Pudendal neuropathy is the only parameter differentiating leakage from solid stool incontinence

PURPOSE

Fecal incontinence may occur in several forms. Although some patients are grossly incontinent, other patients experience only leakage. In patients with gross incontinence, severity can range from the mildest forms (limited to loss of control of flatus) to the most severe forms (involving loss of solid stool). This study was undertaken to determine which physiologic parameters differentiate female patients with incontinence of solid stool from patients with control of formed stool and incontinence limited to seepage.

METHODS

Thirty-eight consecutive female patients with a primary complaint of seepage or solid stool incontinence were evaluated using water perfusion manometry, balloon inflation assessment of rectal sensitivity, and pudendal nerve terminal motor latency. A prospectively maintained database was used for collection of data. The findings in the two patient groups were compared with patients in a group of normal control individuals. Ages of the women in the three groups were similar.

RESULTS

Both groups of patients demonstrated statistically significant (P < 0.05) decreases in rest and squeeze sphincter lengths, pressures, and pressure volumes compared with normal volunteers. The patients also had significantly more asymmetric high-pressure zones and hypersensitive rectums. No significant difference between the two groups of incontinent patients could be identified using any of these parameters. Significant differences between the groups were found in pudendal nerve function. The distal rectoanal excitatory reflex was abnormal in 58.1 percent of grossly incontinent women compared with 28.6 percent of patients with leakage (P < 0.05). The majority of patients with leakage alone (65 percent) had normal pudendal nerve terminal motor latency, whereas only 22.6 percent of women with gross fecal incontinence had normal pudendal nerve terminal motor latency bilaterally (P = 0.01).

CONCLUSIONS

Normal bilateral pudendal nerve function can partially compensate for abnormal sphincter symmetry and function, permitting women with grossly abnormal parameters to maintain control of bowel movements. It remains to be seen whether, with advancing age, patients with leakage will have development of slowed pudendal nerve conduction and, if so, whether their condition will progress to gross incontinence.

Variation in pudendal nerve terminal motor latency according to disease

PURPOSE

The aims of this study were first to establish whether any difference among pudendal nerve terminal motor latency (PNTML) values exists relative to diagnosis, second to determine whether left and right latencies are similar, and third to assess any correlation between age and neuropathy. Latency was elicited three times on each side, and an average latency was recorded as a result.

MATERIALS AND METHODS

Between June 1989 and April 1995, 1,026 patients (775 females and 251 males) underwent PNTML study. These patients were divided into four groups according to diagnosis: Group I, fecal incontinence; Group II, chronic constipation; Group III, idiopathic rectal pain; Group IV, rectal prolapse. Overall mean age was 61.5 (range, 6-95) years. Student's t-test was used to calculate statistical differences. Patients were then analyzed according to age and gender. Correlation was calculated with the nonparametric Mann-Whitney U test.

RESULTS

Unilateral or bilateral prolongation of PNTML was noted in 90 patients (21.2 percent) in Group I, 80 (20.4 percent) in Group II, 22 (18.1 percent) in Group III, and 38 (42.6 percent) in Group IV. Average PNTML on the left side was 1.88 ms in Group I, 1.94 ms in Group II, 1.98 ms in Group III, and 2.12 ms in Group IV. Average PNTML on the right side was 1.85 ms in Group I, 1.94 ms in Group II, 1.99 ms in Group III, and 2.07 ms in Group IV. The only statistically significant differences in PNTML were between Groups I and IV (left, P < 0.005; right, < 0.05) and between females and males (P < 0.0001).

CONCLUSION

There is no statistically significant difference between latencies of left and right pudendal nerves. Similarly, there are no statistically significant differences among patients with fecal incontinence, chronic constipation, or chronic idiopathic rectal pain. Normal latency can be expected in patients with constipation or fecal incontinence. However, patients with rectal prolapse have a more prolonged PNTML. Age is correlated with a higher incidence of pudendal neuropathy. This study reveals significant overlap among PNTML values and diagnosis.

The stimulated gracilis neosphincter for fecal incontinence: a new use for an old concept

The stimulated gracilis neosphincter is a viable procedure in selected patients with fecal incontinence. The aim of this paper is to review the technique of this staged operative procedure and review the problems and complications. Stage 1 consists of the vascular "delay" of the gracilis muscle and the creation of a temporary stoma. Stage 2 consists of transposition of the muscle around the anus with implantation of the stimulator. Low-frequency electrical stimulation is applied to the muscle for 12 weeks, after which stage 3 (stoma closure) is undertaken. From March of 1993 to March of 1995, 14 patients (9 females and 5 males) with a mean age of 44 years (range 20 to 67 years) underwent the procedure. Two patients died within 1 year of the operation from unrelated causes. Two patients developed anal stenosis and required permanent stomas. Other complications noted during ascent of the learning curve included seroma, excoriation of the skin above the stimulator, transposition of the stimulator, premature battery discharge, wound infection, rupture of the gracilis tendon, fatigue during programming sessions, and electrode displacement or fibrosis from the nerve. However, 8 of the 10 eligible patients had stoma reversal; the manometric results showed an average mean squeeze pressure that increased from 43 mmHg prior to surgery to 151 mmHg after the operation (p < 0.01). Based on an objective functional questionnaire, 60 percent of the patients who could be evaluated reported improvement in continence, social interactions, and the quality of their life. In conclusion, despite a steep learning curve, the stimulated gracilis operation is a viable operation for selected patients with severe incontinence.

Stimulated gracilis neosphincter operation. Initial experience, pitfalls, and complications

PURPOSE

The stimulated gracilis neosphincter is accepted as a viable option in select patients with fecal incontinence. The aim of this study was to review the initial problems and complications.

METHODS

A prospective analysis of all patients who underwent this procedure was undertaken. Stage I consisted of the distal vascular delay of the muscle and creation of a temporary stoma. Stage II was the transposition of the muscle and implantation of the stimulator and electrodes. Low frequency electrical stimulation was applied to the muscle for 12 weeks, after which Stage III (stoma closure) was undertaken.

RESULTS

From March 1993 to December 1995, 17 patients (9 females and 8 males) with a mean age of 42.2 (range, 19-72) years underwent the procedure. One patient died from pancreatitis and another from small-bowel adenocarcinoma, three and six months after the procedure, respectively. Two patients (one with Crohn's disease) required permanent stomas. One additional patient required a permanent stoma because of lead fibrosis. Other complications noted during ascent of the learning curve included seroma of the thigh incision, excoriation of the skin above the stimulator, fecal impaction, anal fissure, parastomal hernia, rotation of the stimulator, premature battery discharge, fracture of the lead, perineal skin irritation, perineal sepsis, rupture of the tendon, tendon erosion, muscle fatigue during programming sessions, and electrode displacement from the nerve or fibrosis around the nerve. However, ultimately after rectification of these problems, 13 of the 15 eligible patients had stoma reversal. Manometric results showed an average basal pressure of 43 mmHg and an average maximum squeeze pressure that increased from 36 mmHg before surgery to 145 mmHg by stimulation (P < 0.01). Based on objective functional questionnaires, 9 of 15 (60 percent) evaluable patients reported improvement in continence, social interactions, and quality of life. Three of these nine patients require daily use of enemas.

CONCLUSION

Although the stimulated gracilis operation is a feasible procedure for selected patients with severe incontinence, the learning curve is steep. Although the ultimate outcome in a selected group of patients can be very gratifying, major technical modifications are required before use beyond a research protocol setting. Furthermore, patients must have the psychological strength, emotional commitment, and financial resources that may be necessary for multiple revisional surgeries or ultimate device failure.