Anorectal neuropathy causes anorectal dysfunction, yet it is poorly recognized. This stems from both a lack of understanding of the extrinsic and intrinsic innervation of the anorectum and tools for evaluation of neuronal function. Our objective was to provide an improved understanding of the neuronal networks of the anorectum and discuss its functional significance. We performed a comprehensive and up-to-date review of the published literature on anorectal neuroanatomy to generate our findings. Anorectal nerve innervation appears to be much more complex than hitherto known with an extensive overlap, intercommunications, and variations. The innervations arise from 5 sources as evidenced by immunohistochemical markers: Sympathetic innervation arises from the superior hypogastric plexus, hypogastric plexus, and splanchnic nerves (T1-L2); the parasympathetic from pelvic splanchnic nerves (S1-S4); the mixed autonomic from inferior hypogastric plexus; the somatic from pudendal nerves; and the intercommunicating nerves. Furthermore, they are fine, closely packed nerves susceptible to damage from obstetric or spinal cord injury, or pelvic surgery that may not manifest with bowel problems immediately but later in life. This illustrated review provides a new understanding of the afferent and efferent pathways between the rectum, spinal cord, and brain, and a framework for clinical implications of anorectal neuropathy, such as anal sphincter or rectal sensory or rectal accommodation dysfunction, causing bowel problems. Insights into the functional neuroanatomy provide an improved mechanistic understanding of anorectal symptoms and could facilitate the development of neurophysiological tests such as translumbosacral anorectal magnetic stimulation and neuromodulation treatments such as sacral neuromodulation and translumbosacral neuromodulation treatment.

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.

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.

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.

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

Neuropathy may cause fecal incontinence and mixed fecal incontinence/constipation, but its prevalence is unclear, partly due to the lack of comprehensive testing of spino-anorectal innervation.

This study aimed to develop and determine the clinical usefulness of a novel test, translumbosacral anorectal magnetic stimulation for fecal incontinence.

This observational cohort study was conducted from 2012 to 2018.

This study was performed at a tertiary referral center.

Patients with fecal incontinence, patients with mixed fecal incontinence/constipation, and healthy controls were included.

A translumbosacral anorectal magnetic stimulation test was performed by using an anorectal probe with 4 ring electrodes and magnetic coil, and by stimulating bilateral lumbar and sacral plexuses, uses and recording 8 motor-evoked potentials at anal and rectal sites.

The prevalence of lumbar and/or sacral neuropathy was examined. Secondary outcomes were correlation of neuropathy with anorectal sensorimotor function(s) and morphological changes.

We evaluated 220 patients: 144 with fecal incontinence, 76 with mixed fecal incontinence/constipation, and 31 healthy controls. All 8 lumbar and sacral motor-evoked potential latencies were significantly prolonged (p < 0.01) in fecal incontinence and mixed fecal incontinence/constipation groups compared with controls. Neuropathy was patchy and involved 4.0 (3.0) (median (interquartile range)) sites. Lumbar neuropathy was seen in 29% to 65% of the patients in the fecal incontinence group and 22% to 61% of the patients in the mixed fecal incontinence/constipation group, and sacral neuropathy was seen in 24% to 64% and 29% to 61% of these patients. Anal neuropathy was significantly more (p < 0.001) prevalent than rectal neuropathy in both groups. There was no correlation between motor-evoked potential latencies and anal sphincter pressures, rectal sensation, or anal sphincter defects.

No comparative analysis with electromyography was performed.

Lumbar or sacral plexus neuropathy was detected in 40% to 75% of patients with fecal incontinence with a 2-fold greater prevalence at the anal region than the rectum. Lumbosacral neuropathy appears to be an independent mechanism in the pathogenesis of fecal incontinence, unassociated with other sensorimotor dysfunctions. Translumbosacral anorectal magnetic stimulation has a high yield and is a safe and clinically useful neurophysiological test. See Video Abstract at http://links.lww.com/DCR/B728.

ANTECEDENTES:La neuropatía puede causar incontinencia fecal y una combinación de incontinencia fe-cal/estreñimiento, pero su prevalencia no está clara, en parte debido a la falta de pruebas comple-tas de inervación espino-anorrectal.OBJETIVO:Desarrollar y determinar la utilidad clínica de una nueva prueba, estimulación magnética trans-lumbosacral anorrectal para la incontinencia fecal.DISEÑO:Estudio de cohorte observacional del 2012 al 2018.ENTORNO CLINICO:Centro de referencia terciario.PACIENTES:Pacientes con incontinencia fecal, combinación de incontinencia fecal/estreñimiento y controles sanos.INTERVENCIONES:Se realizó una prueba de estimulación magnética translumbosacral anorrectal utilizando una sonda anorrectal con 4 electrodos anulares y bobina magnética, y estimulando los plexos lumbares y sacros bilaterales y registrando ocho potenciales evocados motores las regiones anal y rectal.PRINCIPALES MEDIDAS DE RESULTADO:Se examinó la prevalencia de neuropatía lumbar y/o sacra. Los resultados secundarios fueron la correlación de la neuropatía con las funciones sensitivomotoras anorrectales y cambios morfológi-cos.RESULTADOS:Evaluamos 220 pacientes, 144 con incontinencia fecal, 76 con combinación de incontinencia fe-cal/estreñimiento y 31 sujetos sanos. Las ocho latencias de los potenciales evocadas motoras lum-bares y sacras se prolongaron significativamente (p <0,01) en la incontinencia fecal y el grupo mixto en comparación con los controles. La neuropatía fue irregular y afectaba 4,0 (3,0) (mediana (rango intercuartílico) sitios. Se observó neuropatía lumbar en 29-65% en la incontinencia fecal y 22-61% en el grupo mixto, y neuropatía sacra en 24-64% y 29-61 % de pacientes respectivamen-te. La neuropatía anal fue significativamente más prevalente (p <0,001) que la rectal en ambos grupos. No hubo correlación entre las latencias de los potenciales evocadas motoras y las presio-nes del esfínter anal, la sensación rectal o los defectos del esfínter anal.LIMITACIONES:Sin análisis comparativo con electromiografía.CONCLUSIÓNES:Se detectó neuropatía del plexo lumbar o sacro en el 40-75% de los pacientes con incontinencia fecal con una prevalencia dos veces mayor en la región anal que en el recto. La neuropatía lumbo-sacra parece ser un mecanismo independiente en la patogenia de la incontinencia fecal, no asocia-do con otras disfunciones sensitivomotoras. La estimulación magnética translumbosacral anorrec-tal tiene un alto rendimiento, es una prueba neurofisiológica segura y clínicamente útil. Consulte Video Resumen en http://links.lww.com/DCR/B728.

Examination for fecal incontinence is performed in order to evaluate the condition of each patient. As there is no single method that perfectly assesses this condition, there are several tests that need to be conducted. These are as follows: anal manometry, recto anal sensitivity test, pudendal nerve terminal motor latency, electromyogram, anal endosonography, pelvic magnetic resonance imaging (MRI) scan, and defecography. In addition, the mental and physical stress most patients experience during all these examinations needs to be taken into consideration. Although some of these examinations mostly apply for patients with constipation, we hereby describe these tests as tools for the assessment of fecal incontinence. Conservative therapies for fecal incontinence include diet, lifestyle, and bowel habit modification, pharmacotherapy, pelvic floor muscle training, biofeedback therapy, anal insert device, trans anal irrigation, and so on. These interventions have been identified to improve the symptoms of fecal incontinence by determining the mechanisms resulting in firmer stool consistency; strengthening the pelvic floor muscles, including the external anal sphincter; normalizing the rectal sensation; or periodic emptying of the colon and rectum. Among these interventions, diet, lifestyle, and bowel habit modifications and pharmacotherapy can be performed with some degree of knowledge and experience. These two therapies, therefore, can be conducted by all physicians, including general practitioners and other physicians not specializing in fecal incontinence. However, patients with fecal incontinence who did not improve following these initial therapies should be referred to specialized institutions. Contrary to the initial therapies, specialized therapies, including pelvic floor muscle training, biofeedback therapy, anal insert device, and trans anal irrigation, should be conducted in specialized institutions as these require patient education and instructions based on expert knowledge and experience. In general, conservative therapies should be performed for fecal incontinence before surgery because its pathophysiologies are mostly attributed to benign conditions. All Japanese healthcare professionals who take care of patients with fecal incontinence are expected to understand the characteristics of each conservative therapy, so that appropriate therapies will be selected and performed. Therefore, in this chapter, the characteristics of each conservative therapy for fecal incontinence are described.

The pelvic floor is a complex anatomical entity and its neuromuscular assessment is evaluated through debated neurophysiological tests. An innovative approach is the study of pelvic floor through dynamic transperineal ultrasound (DTU). The aim of this study is to evaluate DTU sensitivity in recognizing patients with fecal incontinence and to evaluate its concordance with the results of the motor latency studied via pudendal nerve terminal motor latency (PNTML). Female patients affected by FI addressed to our center of coloproctology were prospectively assessed. After a coloproctological evaluation, comprising the PNTML assessment to identify pudendal neuropathy, patients were addressed to DTU to determine anterior and posterior displacement of puborectalis muscle by a blinded coloproctologist. In order to compare the data, a cohort of female healthy volunteers was enrolled. Sixty-eight subjects (34 patients and 34 healthy volunteers) were enrolled. The sensitivities of anterior displacement, posterior displacement and either anterior or posterior displacement in determining the fecal incontinence were 82%, 67% and 91%, respectively. A further high correlation of either anterior or posterior displacement with PTNML was also noted (88%). DTU is an indirect, painless and reproducible method for the identification of the pelvic floor neuromuscular integrity. Its findings seem to highly correlate with FI symptoms and with PNTML results. In the near future, after larger comparative studies, DTU would be considered a potential reliable non-invasive and feasible indirect procedure in the identification of fecal incontinence by pudendal neuropathy. Trial registration number is NCT03933683.

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.

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.

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).

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.

To explore the relationship between such a construct and an existing continence score.

A retrospective study of incontinent patients who underwent anal physiology (AP) was performed. AP results and Cleveland Clinic Continence Scores (CCCS) were extracted. An anal physiology score (APS) was developed using maximum resting pressures (MRP), anal canal length (ACL), internal and external sphincter defects and pudendal terminal motor latency. Univariate associations between each variable, APS and CCCS were assessed. Multiple regression analyses were performed.

Of 508 (419 women) patients, 311 had both APS and CCCS measured. Average MRP was 51 mmHg (SD 23.2 mmHg) for men and 39 mmHg (19.2 mmHg) for women. Functional ACL was 1.7 cm for men and 0.7 cm for women. Univariate analyses demonstrated significant associations between CCCS and MRP (P = 0.0002), ACL (P = 0.0006) and pudendal neuropathy (P < 0.0001). The association between APS and CCCS was significant (P < 0.0001) but accounted for only 9.2% of the variability in CCCS. Multiple regression showed that the variables most useful in predicting CCCS were external sphincter defect, pudendal neuropathy and previous pelvic surgery, but only improving the scores predictive ability to 12.5%.

This study shows that the ability of AP tests to predict continence scores improves when considered collectively, but that a constructed summation model before and after multiple regression is poor at predicting the variability in continence scores.

Faecal incontinence (FI) is a debilitating condition, which affects approximately 2-17 % of the population. Clinical assessment, physiological testing and imaging are usually used to evaluate the pathophysiology and guide management of FI. By analysing patient characteristics, symptoms and investigative findings, the aim of this study was to identify which patient characteristics and investigations influence patient management.

Data was prospectively collected for all patients with FI presenting to a single surgeon at the Royal Prince Alfred Hospital, Sydney, between March 2002 and September 2013. Continuous data was analysed using the independent T-test. Categorical data was analysed using chi-square tests and logistic regression.

Three hundred ninety-eight patients were reviewed; 96 % were female and the mean age was 57 years. Surgical intervention was recommended for 185 patients (47 %) should biofeedback fail. Independent predictors for surgical recommendation were prolapse (p < 0.001, adjusted OR = 4.9 [CI 2.9-8.2]), a functional sphincter length <1 cm (p = 0.032, OR = 1.7 [CI 1.1-2.8]), an external anal sphincter defect (p = 0.028, OR = 1.8 [CI 1.1-3.1]) and a Cleveland Clinic Incontinence Score ≥10 (p = 0.029, OR = 1.7 [CI 1.1-2.6]).

Independent predictors of surgical recommendation included the presence of prolapse, a functional sphincter length <1 cm, an external anal sphincter defect and a Cleveland Clinic Incontinence Score ≥ 10. Pudendal neuropathy was not a predictor of surgical intervention, leading us to question the utility of this investigation.

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.

To determine the value of preoperative anal physiology testing and transanal ultrasonography in predicting clinical response to sacral neuromodulation for fecal incontinence.

We report a retrospective study of all patients treated with sacral neuromodulation for fecal incontinence in a single practice between 2011 and 2014 was performed. Patient demographics included age, gender, comorbidities, presence of an ultrasound-defined external sphincter defect, and history of prior anal sphincter repair. Cleveland Clinic Florida (CCF) scores were used to assess the severity of fecal incontinence at baseline, and at 3, 6 and 12 months. Pearson's correlation coefficient was used to evaluate the relationship between preoperative physiology testing and ultrasonography and patient outcome.

Sacral neuromodulation was trialed in 60 patients, of whom 31 had anorectal physiology testing and 29 did not. Patients who were tested were younger (60.9 vs. 71.4 years, p = 0.013) and more likely to have had a prior overlapping sphincteroplasty (40.5% vs. 15%, p = 0.043). Among patients who progressed to complete system implantation, CCF scores at 3 and 12 months were similar whether they had physiology testing or not. Likewise, patient outcome did not correlate with the finding of an ultrasound-defined external sphincter defect. Pearson's correlation coefficient was used to evaluate the relationship between the test results and the 3-month CCF scores. CCF scores 3 months after full system implantation did not correlate with the presence or size of an external sphincter defect, resting or squeeze pressure, pudendal nerve terminal motor latency, rectoanal inhibitory reflex, or minimum detectable volume.

Anal physiology testing and ultrasonography were not predictive of clinical outcomes among patients treated with sacral neuromodulation for fecal incontinence.

Many tests are available to assist in the diagnosis and management of fecal incontinence. Imaging studies such as endoanal ultrasonography and defecography provide an anatomic and functional picture of the anal canal which can be useful, especially in the setting of planned sphincter repair. Physiologic tests including anal manometry and anal acoustic reflexometry provide objective data regarding functional values of the anal canal. The value of this information is of some debate; however, as we learn more about these methods, they may prove useful in the future. Finally, nerve studies, such as pudendal motor nerve terminal latency, evaluate the function of the innervation of the anal canal. This has been shown to have significant prognostic value and can help guide clinical decision making. Significant advances have also happened in the field, with the relatively recent advent of magnetic resonance defecography and high-resolution anal manometry, which provide even greater objective anatomic and physiologic information about the anal canal and its function.

To quantify changes in pudendal nerve function with sacral neuromodulation (SNM). To understand the relationship of pudendal nerve function to SNM treatment response for overactive bladder. To assess the relationship between female sexual function and pudendal nerve function after SNM.

Women undergoing SNM between January 2010 and May 2011 were enrolled. Baseline pudendal nerve terminal motor latencies (PNTML) were measured bilaterally. Subjects underwent peripheral nerve evaluation (PNE) prior to SNM therapy. PNTML was measured at 1 and 6 weeks after sacral neuromodulator implant. Women who did not undergo permanent implantation were reassessed at the end of the 1-week PNE testing phase. Pelvic floor and sexual function questionnaires were administered at baseline and follow-up to assess pelvic floor and sexual function.

Of 34 women enrolled, 31 were evaluated. Mean age was 67.4 ± 14.2 years with 29/34 (85.3%) treated for refractory overactive bladder. Thirty of 31 (96.7%) went on to a permanent implant. PNE success rate was 73.5% (25/33). Mean PNTML changed from 2.74 ± 0.52 msec at baseline to 2.57 ± 0.50 msec at 6 weeks postop (P = 0.198). Baseline amplitude remained stable at 1 and 6 weeks. At 6 weeks PISQ-12 scores showed improved sexual function (P = 0.034) and PFDI-20 and PFIQ-7 scores showed improved pelvic floor, colorectal and urinary symptoms (P < 0.05).

Women with refractory overactive bladder and non-obstructive urinary retention have abnormal pudendal nerve function, which showed a non-significant trend toward improvement after SNM. Sexually active women undergoing sacral neuromodulation experienced improvement in sexual function. Quality of life improved due to improvement in urinary and colorectal function.

A good understanding of anorectal physiology is essential for the diagnosis and appropriate treatment of various anorectal disorders, such as fecal incontinence, constipation, and pain. This article reviews the physiology of the anorectum and details the various investigations used to diagnose anorectal physiology disorders. These anatomic and functional tests include anal manometry, endoanal ultrasound, defecography, balloon expulsion test, magnetic resonance imaging, pudendal nerve terminal motor latency, electromyography, and colonic transit studies. Indications for investigations, steps in performing the tests, and interpretation of results are discussed.

To determine the contribution of the pudendal nerve to the anal continence mechanism by determining the correlation between pudendal nerve terminal motor latency (PNTML) and resting and squeeze anal canal pressures.

In all, 1051 patients were investigated with anorectal physiology studies between January 1998 and July 2010. Of these, 213 patients had intact anal sphincters on endoanal ultrasound and had undergone PNTML testing and anal manometry with measurement of resting and squeeze pressures. The relationship between PNTML and mean resting and squeeze pressures was compared in these patients with an intact anal sphincter. Values were compared using a two-sample t test with equal variances. A P value of < 0.05 was considered significant.

Of these patients 40.8% had normal PNTML bilaterally, 9.9% had slow PNTML bilaterally and 21.6% had a unilateral slow PNTML. Mean resting pressure was significantly reduced in patients with unilateral slow and bilateral slow PNTML compared with normal. The magnitude of the reduction was 28% and 19% respectively. Mean squeeze pressure was significantly reduced in patients with unilateral slow and bilateral slow PNTML compared with normal. The magnitude of the reduction was 18% and 23% respectively.

In patients with an intact anal sphincter, either unilaterally or bilaterally prolonged PNTMLs are associated with significantly decreased resting and squeeze pressures. Our results suggest that both internal and external sphincter function is impaired with pudendal nerve injury. The inhibition of internal sphincter function may be due to damage of autonomic, principally sympathetic fibres carried in the pudendal nerve.

Anorectal incontinence is a symptom of a complex multifactorial disorder involving the pelvic floor and anorectum, which is a severe disability and a major social problem. Various causes may affect the anatomical and functional integrity of the pelvic floor and anorectum, leading to the anorectal continence disorder and incontinence. The most common cause of anorectal incontinence is injury of the sphincter muscles following delivery or anorectal surgeries. Although the exact incidence of anorectal incontinence is unknown, various studies suggest that it affects ~2.2-8.3% of adults, with a significant prevalence in the elderly (>50%). The successful treatment of anorectal incontinence depends on the accurate diagnosis of its cause. This can be achieved by a thorough assessment of patients. The management of incontinent patients involves conservative therapeutic procedures, surgical techniques, and minimally invasive approaches.

The majority of proctological diseases can be defined by a structured evaluation of the symptoms and a physical examination. Magnetic resonance imaging (MRI) and anal endosonography can detect complex anal fistulas with a high accuracy but MRI should be preferred because of its objective visualization. Functional anorectal disorders are multifactorial and show morphological and functional irregularities in different compartments of the pelvic floor which is why MR defecography is now one of the most important methods in diagnostic algorithms. Interpreting the results of anal endosonography, anal manometry and neurophysiological testing is highly demanding because of large interindividual variability. Scores are used for objective measurement of symptom severity and quality of life. In clinical practice, well validated scores evaluated in large patient groups with predetermined circumstances are needed. Bringing together morphological results with scores based on subjective perception is required to optimize diagnostics and therapy evaluation in proctology.

Atrophy of the external anal sphincter, a pathologic muscle volume anomaly associated with fecal incontinence, has been shown to be a negative predictor of the outcome of surgery for defects of the external anal sphincter. It is unclear whether external anal sphincter atrophy also affects the outcome of sacral nerve stimulation for fecal incontinence.

Our aim was to assess the effectiveness of sacral nerve stimulation in patients with fecal incontinence and external anal sphincter atrophy and to determine whether severity of atrophy and concomitant presence of a sphincter defect are negative predictors of outcome.

This was a prospective observational study of treatment outcome.

The study was conducted from November 2004 through November 2010 at a regional hospital in Italy.

Consecutive patients with fecal incontinence and external anal sphincter atrophy were included. By means of MRI, patients were determined to have either moderate (<50%) or severe (≥ 50%) thinning of and/or replacement of sphincter muscle by fat. The concomitant presence of defects of the external anal sphincter was also detected by MRI.

All patients underwent sacral nerve stimulation through a staged implantation procedure.

The main outcome measures were improvement in the Cleveland Clinic Florida Fecal Incontinence Scale (Wexner score), number of episodes of incontinence per week, and the Fecal Incontinence Quality of Life Scale.

A total of 28 patients underwent definitive implantation of the sacral nerve stimulation device. Wexner scores decreased from a median of 16 (range, 10-20) at baseline to 3 (range, 0-8) at 6-month follow-up (p < 0.001). Weekly incontinence episodes decreased from a mean (SD) of 14.7 (12.5) to 0.40 (0.82); p < 0.001. Improvement was significantly related to severity of fecal incontinence (r = 0.86; p < 0.001). Overall quality-of-life scores improved from a mean of 1.8 (0.6) to 3.8 (0.4);p < 0.001. Sacral nerve stimulation was effective in both moderate (n = 16) and severe (n = 12) atrophy and in patients with (n = 8) or without (n = 20) external anal sphincter defects.

The study was limited by its observational nature and relatively small sample size.

Sacral nerve stimulation can be effective in restoring continence and improving quality of life in patients with fecal incontinence related to atrophy of the external anal sphincter, regardless of the severity of atrophy. Moreover, the presence of EAS atrophy does not influence the success of the outcome of SNS in patients with a sphincter defect. These findings are consistent with the hypothesis that the effects of SNS are not achieved solely by its action on the anal sphincter complex.

We recently found that the anal canal function and external anal sphincter contraction can be enhanced by surgically adjusting the EAS muscle sarcomere length in rabbits. A 20% length plication of the external anal sphincter muscle results in significant increase in the anal canal pressure and EAS muscle stress without affecting its passive tension. The durability of the beneficial effect of external anal sphincter muscle plication on the anal canal function is not known.

We studied the long-term effects of optimal length external anal sphincter plication on the anal canal pressure, external anal sphincter sarcomere length, and anal canal histology.

Female rabbits (n = 16) were anesthetized and either sham (n = 4) or external anal sphincter plication (n = 12) surgery was performed.

The effect of external anal sphincter plication on the anal canal pressure was determined every 2 weeks for 6 months in 6 animals. Anal canal was harvested for sarcomere length and histological assessment.

External anal sphincter plication resulted in 50% to 60% increase in the anal canal pressure, and 80% to 90% increase in external anal sphincter muscle stress (during maximum electrical stimulus). The effect of plication was durable for the entire study period of 24 weeks. Sarcomere length increased from 2.11 ± 0.08 μm to 2.59 ± 0.03 μm immediately after plication and was 2.35 ± 0.08 μm at the end of 6 months. Histology revealed no significant differences in the muscle (30% vs 29%) or connective tissue components (70% vs 71%) of the anal canal between control and chronically plicated animals.

Normal external anal sphincter muscle plication results in long-term enhancement of the anal canal function without any untoward effects on the tissue architecture in the rabbit. External anal sphincter muscle plication could be an important strategy to improve the anal canal function in patients with anal incontinence.

Our recent studies show that the external anal sphincter muscle (EAS) operates at a sarcomere length range which is below optimal. In this study, we tested the hypothesis that by surgically increasing sarcomere length and bringing it close to the optimal length, EAS muscle function and anal canal pressure can be enhanced.

Rabbits (n = 25) were anesthetized and subjected to either a sham or an EAS plication of different length by placing sutures at two locations, at a distance of 13%, 20%, 28%, or 35% of the circumferential length of the anal canal. Anal canal pressures were recorded before and after the plication. Anal canal was harvested and the EAS muscle sarcomere length was measured using laser diffraction.

Electrical stimulation of the EAS muscle resulted in a stimulus-dependent increase in the anal canal pressure (mmHg) and EAS muscle stress (mN mm(-2)). A significant increase in maximal pressure (212 ± 13 after compared with 139 ± 22 before plication) as well as stress (166 ± 10 after as compared with 88 ± 14 before plication) was recorded at 20% plication length. Passive anal canal stress at 20% plication was not significantly different compared with the sham group. The mean sarcomere lengths with sham and 20% plication were 2.11 and 2.60 μm, respectively.

EAS plication resulted in a length-dependent increase in EAS muscle sarcomere length with an optimal sarcomere length at 20% plication. These considerations may help guide repair of anal sphincter muscle defects in the humans.

Disorders of the pelvic floor are common sources of morbidity, decreased quality of life, and are unfortunately increasing in incidence. Owing to their complex and often coexistent nature, a comprehensive, multidisciplinary strategy of testing and care is required. Many nonoperative and operative approaches for management of the symptoms of pelvic floor disorders are available. This article reviews the evaluation and management for these difficult disorders.

Endoanal ultrasound is a well-established technique used to evaluate benign anorectal disorders. The technique is easy to perform, has a short learning curve and causes very little discomfort. Reconstruction of 3D images is possible. The clinical indications for endoanal ultrasound in benign anorectal diseases are fecal incontinence and peri-anal fistula. Sphincter defects can be depicted with precision and correlate perfectly with surgical findings. Furthermore, an impression of sphincter atrophy can be established. With perianal fistula the tracts can be visualized. Introducing hydrogen peroxide via the external fistula opening improves imaging. Endoanal ultrasound and MRI have comparable results in diagnosing anorectal disorders.

Fecal incontinence may be due to postpartum anal sphincter injuries or neurological damage even in the absence of obvious perineal trauma. Anal physiologic testing with transrectal ultrasound, manometry, and pudendal nerve terminal latency studies help to identify those patients with anal sphincter injuries who might benefit from anal sphincter repair. In this article, the authors discuss the specific tests that are available and how to interpret them.

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.

Pudendal neuropathy and fecal incontinence frequently coexist; however, the contribution of neuropathy is unknown. The pudendal nerve innervates the external anal sphincter muscle, anal canal skin, and coordinates reflex pathways. Lateral dominance or a dominantly innervating nerve and its subsequent damage may have major implications in the etiology and treatment of fecal incontinence. This study was designed to establish the prevalence of pudendal neuropathy, in particular a unilateral one, and to examine the impact on anorectal function.

A total of 923 patients (745 females; mean age, 52 (range, 17-92) years) with fecal incontinence were studied using endoanal ultrasonography, anorectal manometry, rectal sensation, and pudendal nerve terminal motor latencies.

A total of 520 patients (56 percent) demonstrated a pudendal neuropathy, which was unilateral in 38 percent (351 patients; 169 right-sided, 182 left-sided). Neuropathy, whether it was bilateral (bilateral vs. normal; 56 (range, 7-154) cm H2O) vs. 67 (range, 5-215) cm H2O; P < 0.01) or unilateral (unilateral vs. normal; 61 (range, 0-271) cm H2O vs. 67 (range, 5-215) cm H2O; P = 0.04) was associated with reduced anal resting tone. This also was seen with respect to squeeze increments (bilateral vs. normal; 34 (range, 0-207) cm H2O vs. 52 (range, 0-378) cm H2O; P < 0.001, unilateral vs. normal; 41 (range, 0-214) cm H2O vs. 52 (range, 0-378) cm H2O; P < 0.01). In those with intact sphincters, unilateral neuropathy was associated with reduced squeeze increments (unilateral vs. normal; 60 (range, 10-286) cm H2O vs. 69 (range, 7-323) cm H2O; P = 0.01) but no significant reduction in resting pressures. There was no association between pudendal neuropathy and abnormal rectal sensitivity.

Unilateral pudendal neuropathy is a common abnormality in individuals with fecal incontinence and is significantly associated with both attenuated resting pressures and squeeze increments. Although there are limitations in the interpretation of pudendal nerve terminal motor latencies, this study demonstrates that further exploration of the concept of lateral dominance is needed.