Rectal Perception Research Articles

Digital technologies for bowel management: A scoping review

The use of digital technologies in managing bowel conditions has been a topic of interest among healthcare practitioners. The objectives of this paper were to provide information about the types of digital technologies that have been used for bowel management and the context of the studies; identify the gaps and challenges in digital technologies for bowel management and propose new methods and techniques for the application of digital technologies in bowel management. A scoping review was conducted following the principles of Preferred Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR). A search was conducted on six academic databases. 1891 papers were retrieved from the initial search; however, 6 papers were included based on the inclusion and exclusion criteria. The findings suggest that published work focused mainly on a research context and with a narrow focus targeting sub-categories of bowel conditions and not implemented in the context of everyday use. The findings also illustrate the variety of early-stage developments focused on increasing support for severe bowel dysfunction, for example, through biofeedback to aid muscle control training, or the placement of artificial anal sphincters to increase rectal perception. However, technology to support bowel management for broader populations with less severe or variable symptoms appears limited. Future work would be to conduct empirical research in the application of advanced technologies such as on-organ sensors in managing bowel conditions.

Subtyping irritable bowel syndrome using cluster analysis: a systematic review

BackgroundIrritable bowel syndrome (IBS) is a common chronic functional gastrointestinal disorder associated with a wide range of clinical symptoms. Some researchers have used cluster analysis (CA), a group of non-supervised learning methods that identifies homogenous clusters within different entities based on their similarity.Objective and methodsThis literature review aims to identify published articles that apply CA to IBS patients. We searched relevant keywords in PubMed, Embase, Web of Science, and Scopus. We reviewed studies in terms of the selected variables, participants’ characteristics, data collection, methodology, number of clusters, clusters’ profiles, and results.ResultsAmong the 14 articles focused on the heterogeneity of IBS, eight of them utilized K-means Cluster Analysis (K-means CA), four employed Hierarchical Cluster Analysis, and only two studies utilized Latent Class Analysis. Seven studies focused on clinical symptoms, while four articles examined anocolorectal functions. Two studies were centered around immunological findings, and only one study explored microbial composition. The number of clusters obtained ranged from two to seven, showing variation across the studies. Males exhibited lower symptom severity and fewer psychological findings. The association between symptom severity and rectal perception suggests that altered rectal perception serves as a biological indicator of IBS. Ultra-slow waves observed in IBS patients are linked to increased activity of the anal sphincter, higher anal pressure, dystonia, and dyschezia.ConclusionIBS has different subgroups based on different factors. Most IBS patients have low clinical severity, good QoL, high rectal sensitivity, delayed left colon transit time, increased systemic cytokines, and changes in microbial composition, including increased Firmicutes-associated taxa and depleted Bacteroidetes-related taxa. However, the number of clusters is inconsistent across studies due to the methodological heterogeneity. CA, a valuable non-supervised learning method, is sensitive to hyperparameters like the number of clusters and random initialization of cluster centers. The random nature of these parameters leads to diverse outcomes even with the same algorithm. This has implications for future research and practical applications, necessitating further studies to improve our understanding of IBS and develop personalized treatments.

Symptom Improvement of ulceRative colitis after an Induction dose of UStekinumab in Japanese clinical practice (SIRIUS), measured using patient-reported outcomes: a prospective observational study

IntroductionUlcerative colitis (UC) is an idiopathic, chronic inflammatory disease of the large intestine. Ustekinumab is a monoclonal antibody against the p40 subunit of interleukin-12 and interleukin-23 and has proven efficacy...

Preliminary study of a novel artificial anal sphincter with perception reconstruction

Artificial anal sphincter (AAS), as an advanced device, has been widely investigated by researchers around world. But the reliability of the structure is still unsatisfactory according to clinical results. What's more, the previous AAS systems are lack the ability of rectal perception as native anal sphincter, which fails to guarantee the safety of the blood supply. In addition, without it, the patient cannot determine when to defecate. In order to improve the reliability and safety of current AAS systems, a novel structure AAS system with rectal perception function, based on pressure sensor module, is proposed in this article. The novel AAS system has a closed three-arm clamping mechanism, with transmission structure of cam-follower system. Then, the design, strength check, optimization and force analysis of the proposed mechanism are investigated. After that, to remodel rectal perception function, the novel sensor module system based on strain gauge is established. Finally, in vitro experiments are conducted. In vitro test, the sensor system could monitor the rectal pressure accurately. And when H=24.6cm (feeling the urge to have a bowel movement), the clamping pressure is 7.39kPa. which is also less than the safe pressure 9.33kPa. Good performance of the reliability and safety of both novel rectal perception function and new clamping mechanism have been showed.

Volumetric Rectal Perception Testing: Is It Clinically Relevant? Results From a Large Patient Cohort.

Rectal perception testing is a recommended component of anorectal physiology testing. Although recent consensus (London) guidelines suggested criteria for categorizing hyporectal and hyper-rectal sensitivity, these were based on scant evidence. Moreover, data regarding diagnostic capabilities and clinical utility of rectal perception testing are lacking. The aims of this study were to determine the association between rectal perception testing and both clinical and physiological variables to enhance the analysis and interpretation of real-life test results. Prospectively documented data from 1,618 (92% female) patients referred for anorectal physiology testing were analyzed for 3 rectal perception thresholds (first, urge, and maximal tolerated). Normal values derived from healthy female subjects were used to categorize each threshold into hyposensitive and hypersensitive to examine the clinical relevance of this categorization. There was poor to moderate agreement between the 3 thresholds. Older age, male sex, and constipation were associated with higher perception thresholds, whereas irritable bowel syndrome, fecal incontinence, connective tissue disease, and pelvic radiation were associated with lower perception thresholds to some, but not all, thresholds (P < 0.01 on multivariate analysis for all). The clinical utility and limitations of categorizing thresholds into "hypersensitivity" and "hyposensitivity" were determined. Commonly practiced rectal perception testing is correlated with several disease states and thus has clinical relevance. However, most disease states were correlated with 2 or even only 1 abnormal threshold, and agreement between thresholds was limited. This may suggest each threshold measures different pathophysiological pathways. We suggest all 3 thresholds be measured and reported separately in routine clinical testing.

Kegel Exercises, Biofeedback, Electrostimulation, and Peripheral Neuromodulation Improve Clinical Symptoms of Fecal Incontinence and Affect Specific Physiological Targets: An Randomized Controlled Trial.

Background/AimsFecal incontinence (FI) is a prevalent condition among community-dwelling women, and has a major impact on quality of life (QoL). Research on treatments commonly used in clinical practice—Kegel exercises, biofeedback, electrostimulation, and transcutaneous neuromodulation—give discordant results and some lack methodological rigor, making scientific evidence weak. The aim is to assess the clinical efficacy of these 4 treatments on community-dwelling women with FI and their impact on severity, QoL and anorectal physiology.MethodsA randomized controlled trial was conducted on 150 females with FI assessed with anorectal manometry and endoanal ultrasonography, and pudendal nerve terminal motor latency, anal/rectal sensory-evoked-potentials, clinical severity, and QoL were determined. Patients were randomly assigned to one of the following groups Kegel (control), biofeedback + Kegel, electrostimulation + Kegel, and neuromodulation + Kegel, treated for 3 months and re-evaluated, then followed up after 6 months.ResultsMean age was 61.09 ± 12.17. Severity of FI and QoL was significantly improved in a similar way after all treatments. The effect on physiology was treatment-specific Kegel and electrostimulation + Kegel, increased resting pressure (P < 0.05). Squeeze pressures strongly augmented with biofeedback + Kegel, electrostimulation + Kegel and neuromodulation + Kegel (P < 0.01). Endurance of squeeze increased in biofeedback + Kegel and electrostimulation + Kegel (P < 0.01). Rectal perception threshold was reduced in the biofeedback + Kegel, electrostimulation + Kegel, and neuromodulation + Kegel (P < 0.05); anal sensory-evoked-potentials latency shortened in patients with electrostimulation + Kegel (P < 0.05).ConclusionsThe treatments for FI assessed have a strong and similar efficacy on severity and QoL but affect specific pathophysiological mechanisms. This therapeutic specificity can help to develop more efficient multimodal algorithm treatments for FI based on pathophysiological phenotypes.

Solitary rectal ulcer syndrome in 102 patients: Do different phenotypes make sense?

BackgroundLittle is known about the pathophysiological mechanisms of solitary rectal ulcer syndrome (SRUS). AimsWe aim to identify the different phenotypes, taking into account complaints, anatomy and anorectal physiology. MethodsComplaints, endoscopy results, and physiology data of patients with histologically proven SRUS were collected and analysed. The associated anorectal diseases were faecal incontinence and obstructed defecation. The clinical aspects of SRUS were compared, and factors associated with anorectal diseases were identified. ResultsOverall, 102 consecutive patients were included. The predominant lesion was a rectal ulcer (66%), and inflammation of the rectal wall was present in 42% of patients. Abnormal rectal capacities and/or rectal perception was observed in more than half. Nearly half (52%) of the patients met the criteria for obstructed defecation and they tended to more frequently have psychiatric disease (66.7% vs 33.3%; p=0.07). Patients with faecal incontinence (17%) reported more self-perception of anal procidentia (p=0.01) and were more likely to have inflammation of the rectal wall (p=0.02), high-grade internal rectal procidentia (p=0.06) and anal hypotonia (p=0.004); their maximum tolerable volume was lower (p=0.004). ConclusionThe characteristics of patients with SRUS suggest different phenotypes. This may be a way to develop a comprehensive treatment strategy.

Design and evaluation of puborectalis-like artificial anal sphincter that replicates rectal perception.

While fecal incontinence (FI) is not fatal, it can dramatically decrease the patient's quality of life. An artificial anal sphincter (AAS) is an implantable device that treats FI by replacing a diseased or damaged anal sphincter, thus allowing the patient's continence to be maintained. Here, we report a novel implantable puborectalis-like artificial anal sphincter (PAAS) that replicates rectal perception and has a low risk of ischemia necrosis. Using the pressure sensors embedded in the PAAS, the relationship between the mass of feces and the pressure was determined, and a feces mass estimation model was developed based on invitro studies. Rectal perception is provided through the real-time monitoring of rectal feces, and the feeling of defecation is quantified based on a comparison between the feces mass and a preset threshold mass. Invivo studies were performed for validation, and the accuracy of the model was determined to be as high as 90%. The performance of the PAAS in the real-time monitoring of rectal feces and its invivo biocompatibility were also evaluated. The device should further the functionality of existing AAS systems while improving their biosafety and thus expand the applicability of implantable AAS systems in the treatment of FI.

The role of physical therapy in the treatment of children with chronic functional constipation

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Research of improved fast independent component analysis algorithm in rectal diagnosis signal preprocessing.

With the maturity of artificial organ technology, the use of artificial anal sphincters was proposed to help patients who suffered anal incontinence for various causes reconstruct rectal perception, monitor rectal pressure and diagnose rectal lesion. Aimed at the lack of signal pretreatment in the artificial anal sphincter system, we find a way to solve it, that is, the multi-dimensional reconstruction of the intestinal one-dimensional pressure signal sequence by using phase space reconstruction, and the separation of the reconstructed signal by using the improved fast independent component analysis algorithm. We did some relevant experiments, further extracted the features of the isolated rectal signal, and used back propagation neural network to diagnose the rectal lesions. Experiments show that the method can pretreat the rectal signal, and further analyze the separated signal to diagnose of rectal function. The improved fast independent component analysis algorithm has few iterations, fast convergence, short run time, low requirements on initial weights and good diagnosis. This study lays a foundation for the diagnosis of rectal function by using artificial anal sphincters.

A novel power supply system for puborectalis‐like artificial anal sphincter

Puborectalis-like artificial anal sphincter (PAAS) is an innovative new type of artificial anal sphincter (AAS). It overcomes many drawbacks and inadequacies of various previous AASs, and it has successfully been implanted in vivo for almost 3 weeks. During in vivo testing, PAAS shows its ability to retain continence with low risk of ischemia necrosis, and somehow truly helps to remodel rectal perception. However, there are still many defects that influence the long-term implantation of PAAS, especially in the power supply system (PSS). This article presents a new designed PSS which includes a new transcutaneous energy transfer (TET) system, a heat reduction system, and a safety usage system. The new PSS reduces the total size of PAAS by at least 30%. Newly designed TET system can satisfy the Qi standard, and render a power of 3W to fulfill the requirement of fast charging and normal use of PAAS at the distance of 15.5mm when frequency of TET system is 110 kHz, which previous TET systems can hardly achieve. Heat reduction system helps to reduce the heat generated during TET charging. It can reduce heat by 40% during the same period of time of TET charging. Safety usage system helps the user control PAAS more properly which can reduce the rate of failure of PAAS system.

Transcutaneous electric nerve stimulation over acupoints for patients with diarrhea-predominant irritable bowel syndrome: Protocol for systematic review and meta-analysis.

Background:At present, drug therapy for diarrhea-predominant irritable bowel syndrome (IBS-D) has made great progress; however, it does not often produce a satisfying curative effect. Transcutaneous electric nerve stimulation over acupoints (Acu-TENS) might be more effective in improving patient's symptoms and producing fewer side-effects as a result.Although with a great progress of the drug therapy for IBS-D, it is often hard to achieve its satisfactory curative effect. Acu-TENS that may be effective to improve patients’ symptoms and fewer side-effects will be sought. There is no systematic review concerning the efficacy of Acu-TENS for IBS-D published. Therefore, this review aims to systematically evaluate the efficacy of Acu-TENS on IBS-D.Methods:Four English (PubMed, EMBASE, The Cochrane Library, Web of Science) and 4 Chinese electronic databases (Biomedical Literature Database, CNKI, VIP, Wanfang Database) will be searched from their inception to November 26, 2018. Randomized controlled trials that evaluated the effect of Acu-TENS on patients with IBS-D will be included. The primary outcome measures will include average weekly stool frequency, visual analog scale (VAS), and the Bristol scale. The secondary outcome measures will include the MOS 36-item short-form health survey (SF-36), IBS Quality of Life Questionnaire (IBS-QOL), severity of IBS symptoms (IBS-SSS), and rectal perception. Quality evaluation and data extraction will be independently undertaken, respectively. The data from the eligible trials will be analyzed by RevMan5.3.Results:For patients with IBS-D, this systematic review will provide evidences related to the efficacy of Acu-TENS in these evaluation aspects, stool frequency, VAS and the Bristol scale, SF-36, IBS-QOL, IBS-SSS, and rectal perception.Conclusion:This evidence may be useful to medical workers with regard to the use of Acu-TENS in the treatment of IBS-D.PROSPERO registration number: PROSPERO CRD442018109294.

Fecal incontinence in patients with spina bifida: The target is the rectum.

The prevalence rate of severe fecal incontinence (FI) in adults with spina bifida (SB) is high. The physiological basis of FI in SB has not been clearly established, which contributes to inadequate care. The aim was to better characterize a large cohort of adults with special consideration of anorectal physiology. A multidisciplinary team from a French referral centre for SB prospectively collected data on patients who had an anorectal manometry. Factors associated with severe FI (Cleveland clinical incontinence score ≥ 9) were assessed in a multivariate analysis model. A total of 132 adults with SB (sex ratio M/F: 55 [41.7%]/77 [58.3%]; mean age of 38.2 [11.6] years old) were assessed. Among these patients, 83/132 (62.9%) suffered from severe FI. Rectal perception was not evaluable among 17 patients who had a latex allergy. Overall, 29/115 (25.2%) had maximal tolerable volume (MTV) > 330 mL or no sensation. The absence of anal canal sensitivity, MVT > 330 mL and the amplitude of the recto-anal inhibitory reflex (RAIR) >75% after a rectal isovolumic inflation of 50 mL were significantly associated with severe FI in the multivariate analysis model. Neither neurological level nor other neurological features were associated with severe FI. This study showed that FI in patients with SB is mainly associated with rectal abnormalities. This should be taken into consideration to improve incontinence management of patients with SB.

Preliminary Study of a Novel Puborectalis-Like Artificial Anal Sphincter.

Artificial anal sphincter (AAS) is an in situ implanted device that acts as a treatment for fecal incontinence regardless of etiology by augmenting the incompetent sphincteric structures. However, AAS is impeded from becoming a valid therapy by its high rate of ischemic complication and malfunction. This article presents an original puborectalis-like artificial anal sphincter (PAAS) that features a low risk of ischemia necrosis and rectal perception remodeling. The device retains continence by reproducing the action, including the pulling and angulating the rectum, of the puborectalis muscle, which forms the anorectal angle and reduces the required clamping pressure. Three rectal pressure sensors were embedded to maintain the pressure exerted on the rectal wall in a safe range and to monitor the distention of the rectum. A series of in vitro studies were conducted with a porcine rectum, and this PAAS prototype manifested the ability of maintaining continence with a clamping pressure considerably lower than that required by other AAS devices. The pressure sensors exhibit good linearity, and the function of rectal perception remodeling has also revealed high reliability with a success rate of 93.3%.

Brain functional connectivity is associated with visceral sensitivity in women with Irritable Bowel Syndrome.

Increased perception of visceral stimuli is a key feature of Irritable Bowel Syndrome (IBS). While altered resting-state functional connectivity (rsFC) has been also reported in IBS, the relationship between visceral hypersensitivity and aberrant rsFC is unknown. We therefore assessed rsFC within the salience, sensorimotor and default mode networks in patients with and without visceral hypersensitivity and in healthy controls (HCs).An exploratory resting-state functional magnetic resonance imaging study was performed in 41 women with IBS and 20 HCs. Group independent component analysis was used to derive intrinsic brain networks. Rectal thresholds were determined and patients were subdivided into groups with increased (hypersensitive IBS, N = 21) or normal (normosensitive IBS, N = 20) visceral sensitivity. Between-group comparisons of rsFC were carried-out using region-of-interest analyses and peak rsFC values were extracted for correlational analyses.Relative to normosensitive IBS, hypersensitive patients showed increased positive rsFC of pregenual anterior cingulate cortex and thalamus within the salience network and of posterior insula within the sensorimotor network. When compared to both hypersensitive IBS and HCs, normosensitive IBS showed decreased positive rsFC of amygdala and decreased negative rsFC in dorsal anterior insula within the DMN. DMN and sensorimotor network rsFC were associated with rectal perception thresholds, and rsFC in posterior insula was correlated with reported symptom severity in IBS.Our exploratory findings suggest that visceral sensitivity in IBS is related to changes in FC within resting-state networks associated with interoception, salience and sensory processing. These alterations may play an important role in hypervigilance and hyperalgesia in IBS.

Absence of diurnal variation in visceromotor response to colorectal distention in normal Long Evans rats

Background: Enhanced colorectal sensitivity (i.e. visceral hypersensitivity) is thought to be a pathophysiological mechanism in irritable bowel syndrome (IBS). In healthy men a circadian variation in rectal perception to colonic distention was described. Disturbed day and night rhythms, which occur in shift work and trans meridian flights, are associated with the prevalence of IBS. This raises the question whether disruptions of circadian control are responsible for the observed pathology in IBS. Prior to investigating altered rhythmicity in relation to visceral hypersensitivity in a rat model for IBS, it is relevant to establish whether normal rats display circadian variation similar to healthy men. Methodology and findings: In rodents colorectal distension leads to reproducible contractions of abdominal musculature. We used quantification of this so called visceromotor response (VMR) by electromyography (EMG) to assess visceral sensitivity in rats. We assessed the VMR in normal male Long Evans rats at different time points of the light/dark cycle. Although a control experiment with male maternal separated rats confirmed that intentionally inflicted (i.e. stress induced) changes in VMR can be detected, normal male Long Evans rats showed no variation in VMR along the light/dark cycle in response to colorectal distension. Conclusions: In the absence of a daily rhythm of colorectal sensitivity in normal control rats it is not possible to investigate possible aberrancies in our rat model for IBS.

Absence of diurnal variation in visceromotor response to colorectal distention in normal Long Evans rats.

Enhanced colorectal sensitivity (i.e. visceral hypersensitivity) is thought to be a pathophysiological mechanism in irritable bowel syndrome (IBS). In healthy men a circadian variation in rectal perception to colonic distention was described. Disturbed day and night rhythms, which occur in shift work and trans meridian flights, are associated with the prevalence of IBS. This raises the question whether disruptions of circadian control are responsible for the observed pathology in IBS. Prior to investigating altered rhythmicity in relation to visceral hypersensitivity in a rat model for IBS, it is relevant to establish whether normal rats display circadian variation similar to healthy men. In rodents colorectal distension leads to reproducible contractions of abdominal musculature. We used quantification of this so called visceromotor response (VMR) by electromyography (EMG) to assess visceral sensitivity in rats. We assessed the VMR in normal male Long Evans rats at different time points of the light/dark cycle. Although a control experiment with male maternal separated rats confirmed that intentionally inflicted (i.e. stress induced) changes in VMR can be detected, normal male Long Evans rats showed no variation in VMR along the light/dark cycle in response to colorectal distension. In the absence of a daily rhythm of colorectal sensitivity in normal control rats it is not possible to investigate possible aberrancies in our rat model for IBS.

Research on biomechanical compatibility for the artificial anal sphincter based on rectal perception function reconstruction

To treat the anal incontinence, a new artificial anal sphincter is put forward. Aiming at the rectal perception function reconstruction and the mechanical compatibility for artificial anal sphincter, this paper regards the huge mobile contraction wave in the typical rectal pressure contraction waves as the main signal of defecation. Meanwhile, by extracting features of rectal pressure signals with the help of wavelet packet analysis, and by adopting the Davies Bouldin index (DB) optimal algorithm, rectal perception function reconstruction is realised through predicting the defecation by means of the SVM classifier. In order to avoid the rectal ischemia necrosis, a three-dimensional finite element model for the rectum and artificial anal sphincter is constructed, with the purpose of analysing the viscoelasticity of the rectum. Then, prony series is deduced by utilising the constitutive equation of rectum, and finite element analysis for artificial anal sphincter is conducted by simulating the contraction and relaxation of the sphincter to generate load. At last, the shift and the stress distribution for the rectum at the time of being oppressed are obtained. This simulative experiment result shows that the artificial anal sphincter can highly accurately predict the defecation and it features favorable biomechanical compatibility.

Psychological factors selectively upregulate rectal pain perception in hypersensitive patients with irritable bowel syndrome.

Visceral hypersensitivity and psychological symptoms are frequent features in irritable bowel syndrome (IBS). Exploring mechanistic pathways leading to visceral hypersensitivity is of importance to direct future studies and treatment options. In this study, we evaluated the contribution of psychological factors to the perception of painful and non-painful rectal sensations in hyper- vs normosensitive IBS patients. We included 138 IBS patients (Rome II criteria) who underwent an ascending method of limited rectal balloon distension paradigm. At the end of each distension step, subjects rated the perceived intensity of non-painful ('unpleasantness') and painful rectal sensations on visual analog scales. Sensitivity status was determined based on pain thresholds. Anxiety, depression and somatization were assessed by questionnaires. Mixed models were used to test the relationship between sensitivity status, psychological variables, and pain & unpleasantness ratings upon increasing distension. Hypersensitive IBS patients had lower sensory thresholds for pain, first perception, urge to defecate, and discomfort (p<0.0001). Upon increasing distension, they rated both painful and non-painful sensations as more intense than normosensitive patients (p<0.0001). Psychological factors were associated with higher painratings during distension in hypersensitive (p<0.006-0.0001), but not in normosensitive patients. Anxiety, but not depression or somatization, was associated with increased intensity ratings of non-painful sensations (p<0.001), independent of sensitivity status. Hypersensitive IBS patients are characterized by increased perception of pain, but also of non-painful sensations. Psychological factors increase the perception of painful sensations in hypersensitive patients only, whereas non-painful visceral sensations were exaggerated in anxious patients regardless of the sensitivity status.

Anorectal dysfunction in patients with ulcerative colitis: impaired adaptation or enhanced perception?

Rectal disorders during ulcerative colitis (UC) drastically alter the quality of life and may result from an impairment of rectal perception and compliance. This study aims to assess anorectal disorders in patients with mild-to-moderate UC. Anal pressures and the rectal responses to phasic rectal isobaric distension in 10 patients with mild-to-moderate UC were prospectively compared with those in 10 healthy volunteers (HVs). The patients in each group were similar regarding age, gender, and delivery. In the resting state, the anal canal pressures were similar between the groups. Only the squeeze pressures of the lower anal canal were significantly lower in UC patients than in HVs. During phasic isobaric distension, rectal sensitivity was similar between the groups, whatever the step of distension. Isobaric rectal distension resulted in a significant decrease of the rectoanal inhibitory reflex and a decrease in rectal tone and a significant drop in rectal compliance in UC patients compared with HVs. Patients showing mild-to-moderate UC experience rectal compliance and innervation disorders without a significant change in rectal sensitivity. The findings of this work suggest impairment not only of the properties of the rectal wall but also of intrinsic innervation. Repeated evaluation over time may be helpful for analyzing the reversibility of the process after healing.