Effects and Mechanisms of Anal Electrical Stimulation on Anorectal Compliance and Tone in Dogs

Purpose This study was designed to investigate the changes in rectal compliance and tone during anal electric stimulation and the involvement of the α-adrenergic pathway in conscious dogs. Methods Eight healthy dogs were studied in five randomized sessions. Anal sphincter pressure was quantified by using the area under the contractile curve. Rectal compliance and tone were measured in a pressure-controlled phasic and isobaric distention by using an electronic barostat. Anal electric stimulation was performed via a pair of ring electrodes attached to the catheter. Results The electric stimulation-induced increase in sphincter pressure was lowered by the presence of an α₁-adrenergic receptor antagonist, prazosin (18.6 ± 7.4 vs. 45.4 ± 9.7, P < 0.05), or α₂-adrenergic receptor antagonist, yohimbine (10.2 ± 8.2 vs. 38.3 ± 7.6, P < 0.05), compared with the control. The threshold volume in rectoanal inhibitory reflex during electric stimulation was significantly higher than during baseline (27.5 ± 0.9 vs. 22.5 ± 1.9 ml, P < 0.05). There were no significant differences between the percentage drops in sphincter pressure with and without stimulation at a rectal distention level of 45 ml of air. Anal electric stimulation significantly increased rectal compliance reflected as reduced P_1/2 (11.1 ± 1.5 vs. 16.7 ± 1.1, P = 0.027) and reduced κ (11.6 ± 2.5 vs. 20.5 ± 2.6, P = 0.0095), compared with the control session, but did not significantly alter rectal tone. Conclusions Anal electric stimulation increases anal sphincter pressure, mediated at least partially by the α-adrenergic pathway. It also increases rectal compliance but does not alter rectal anal inhibitory reflexes.     

Anorectal pressure gradient and rectal compliance in fecal incontinence

To study whether anorectal pressure gradients discriminated better than standard anal manometry between patients with fecal incontinence and subjects with normal anal function, anorectal pressure gradients were measured during rectal compliance measurements in 36 patients with fecal incontinence and in 22 control subjects. Anal and rectal pressures were measured simultaneously during the rectal compliance measurements. With standard anal manometry, 75% of patients with fecal incontinence had maximal resting pressure within the normal range, and 39% had maximum squeeze pressure within the normal range. Anorectal pressure gradients did not discriminate better between fecal incontinence and normal anal function, since, depending on the parameters used, 61%–100% of the incontinent patients had anorectal pressure gradients within the normal range. Patients with fecal incontinence had lower rectal volumes than controls at constant defecation urge (median 138 ml and 181 ml, P<0.05) and at maximal tolerable volume (median 185 ml and 217 ml, P<0.05). We conclude that measurements of anorectal pressure gradients offer no advantage over standard anal manometry when comparing patients with fecal incontinence to controls. Patients with fecal incontinence have a lower rectal volume tolerability than control subjects with normal anal function. Accepted: 5 June 1998     

Morbid Obesity Adversely Impacts Pelvic Floor Function in Females Seeking Attention for Weight Loss Surgery

Purpose This study was designed to determine the impact of excess body mass on the prevalence of pelvic floor disorders in morbidly obese females. Methods A total of 358 morbidly obese females (body mass index (BMI) ≥ 35 kg/m²) completed two validated, condition-specific, quality of life questionnaires of pelvic floor dysfunction, which assessed stress/impact in three main domains of pelvic floor disorders: pelvic organ prolapse, colorectal-anal, and urogenital incontinence. Prevalence and severity scores in the study population were compared with data from 37 age-matched nonobese controls (BMI ≤ 35 kg/m²). Results Mean age was 43 ± 11 years vs. 42 ± 12 years, and mean BMI was 50 ± 10 kg/m² vs. 26 ± 4 kg/m² (p = 0.02) in the study and control groups, respectively. Parity and past obstetric history were similar between the groups. Pelvic floor disorders were prevalent in 91 percent of the morbidly obese females compared with 22 percent in the control group (p < 0.001). Scores were statistically significantly higher in the study group for all studied stress/impact domains (p < 0.001 and p = 0.001, respectively). Further stratifications in the study group revealed a significant impact on pelvic floor disorders with increased age (p < 0.003 and p < 0.009 for stress/impact mean scores, respectively) and the presence of other comorbidities (p< 0.008, p < 0.03 for stress/impact prevalence, respectively). Additional increases in BMI > 35 kg/m² did not show increased adverse impacts on pelvic floor disorders symptoms. Conclusion More than 90 percent of morbidly obese females experience some degree of pelvic floor disorders, and 50 percent of these females report that symptoms adversely impact quality of life. In morbidly obese females, obesity is as important as obstetric history in predicting pelvic floor dysfunction. Poster presentation at the meeting of The American Society of Colon and Rectal Surgeons, Seattle, Washington, June 3 to 7, 2006.     

Sonographic Characteristics of Rectal Sensations in Healthy Females

Purpose This study was designed to characterize rectal sensations by visualizing the internal and external anal sphincter and intra-anal transport of bolus during elicited rectal sensations. Methods The anal canal was visualized with real-time transperineal ultrasonography in 13 healthy female volunteers. Rectal sensations were elicited by injecting water into the rectum. The ultrasound images were recorded on a videotape and analyzed offline. Results The median time between an injection of water and the events studied was calculated in 105 rectal sensations. A relaxation in the internal anal sphincter (4 seconds after the injection of water), an antegrade transport of bolus (4 seconds) into the anal canal, and a contraction in the external anal sphincter (5 seconds) were observed before a sensation (6 seconds) was reported. The antegrade flow continued until the distal internal anal sphincter contracted (18 seconds) and the bolus moved in a retrograde transport direction (17 seconds) thereafter the sensation disappeared (18 seconds) and the external anal sphincter relaxed (22 seconds). A significant correlation in time between the end of the sensation, contraction in the internal anal sphincter, reversed flow of anal contents, and relaxation of the external anal sphincter was found (Pearson, P<0.01). Conclusions The results verified that the internal anal sphincter contributes to the perception of rectal sensations by a relaxation allowing intra-anal bolus to increase the pressure on the anoderm during rectal contraction. A new observation is presented on the time relation between contraction in the distal internal anal sphincter, reversed flow in the anal canal, and the end of rectal sensations. Presented at the meeting of the International Continence Society, Christchurch, New Zealand, November 27 to December 1, 2006. Supported by Hitachi Ultrasound, Supfstrasse 24, 6300 Zug Switzerland provided the sonography system. Reprints are not available.     

Electrical Stimulation and Pelvic Floor Muscle Training With Biofeedback in Patients With Fecal Incontinence: A Cohort Study of 281 Patients

Purpose Pelvic floor rehabilitation is an appealing treatment for patients with fecal incontinence but reported results vary. This study was designed to assess the outcome of pelvic floor rehabilitation in a large series of consecutive patients with fecal incontinence caused by different etiologies. Methods A total of 281 patients (252 females) were included. Data about medical history, anal manometry, rectal capacity measurement, and endoanal sonography were collected. Subgroups of patients were defined by anal sphincter complex integrity, and nature and possible underlying causes of fecal incontinence. Subsequently patients were referred for pelvic floor rehabilitation, comprising nine sessions of electric stimulation and pelvic floor muscle training with biofeedback. Pelvic floor rehabilitation outcome was documented with Vaizey score, anal manometry, and rectal capacity measurement findings. Results Vaizey score improved from baseline in 143 of 239 patients (60 percent), remained unchanged in 56 patients (23 percent), and deteriorated in 40 patients (17 percent). Mean Vaizey score reduced with 3.2 points (P < 0.001). A Vaizey score reduction of ≥ 50 percent was observed in 32 patients (13 percent). Mean squeeze pressure (+5.1 mmHg; P = 0.04) and maximal tolerated volume (+11 ml; P = 0.01) improved from baseline. Resting pressure (P = 0.22), sensory threshold (P = 0.52), and urge sensation (P = 0.06) remained unchanged. Subgroup analyses did not show substantial differences in effects of pelvic floor rehabilitation between subgroups. Conclusions Pelvic floor rehabilitation leads overall to a modest improvement in severity of fecal incontinence, squeeze pressure, and maximal tolerated volume. Only in a few patients, a substantial improvement of the baseline Vaizey score was observed. Further studies are needed to identify patients who most likely will benefit from pelvic floor rehabilitation. Supported by grant 945-01-013 of the Netherlands Organization for Health Research and Development. Presented at the United European Gastroenterology Week, Copenhagen, Denmark, October 15 to October 19, 2005. Reprints are not available.     

Anorectal manovolumetry in the decision making before surgery for slow transit constipation

Background Colectomy with ileorectal anastomosis for slow transit constipation (STC) is being challenged by other operations, such as segmental resections. The importance of preoperative anorectal physiology testing may therefore be increased. The aim of this study was to identify anorectal abnormalities in patients with STC, which may influence the surgical approach. Methods Fifty consecutive patients with STC (43 women; median age, 49 years) and 28 controls (23 women; median age, 50 years) were examined with anorectal manovolumetry. Anal pressures and rectal volumes were recorded, at stepwise rectal distension. Results Anal resting pressure was lower in patients (median, 54 cm H₂O; range, 22–130) than in controls (median, 68 cm H₂O; range, 35–100) (p<0.05). Squeeze pressure tended to be lower in patients (median, 147 cm H₂O; range, 53–382) than in controls (median, 177 cm H₂O; range, 65–423) (p=0.09). Rectal sensory thresholds did not differ significantly between patients and controls, although 10 patients had a threshold for filling above the 95^th percentile of controls. Rectal compliance was increased in patients in the pressure interval 5–35 cm H₂O (p<0.05–0.01). The threshold and amplitude of the recto-anal inhibitory reflex did not differ significantly, but the recovery of resting pressure after eliciting the reflex was lower in patients than in controls in the pressure interval 10–50 cm H₂O (p<0.05–0.001). Conclusions More than half of the patients with STC deviated in some parameter. An impaired internal sphincter function and increased rectal compliance were seen. One fifth of the patients had impaired rectal sensation.     

A pilot study of total pelvic floor repair or gluteus maximus transposition for postobstetric neuropathic fecal incontinence

PURPOSE: The aim of this study was to report pilot data comparing the morbidity and functional outcome of total pelvic floor repair with gluteus maximus transposition for women with postobstetric fecal incontinence. METHODS: This is a prospective, randomized trial of two surgical procedures in 24 women so far. Functional assessment was performed with use of a 20-point clinical incontinence score and patient questionnaire before and after operation. The physiologic parameters, before and after operation, included resting and squeeze anal pressures, length of the high pressure zone, anal and rectal mucosal sensitivity, and pudendal nerve latency. RESULTS: So far, 12 patients have been treated by total pelvic floor repair and 12 by gluteus maximus transposition. Of these, three patients developed wound complications after gluteus maximus transposition compared with none after total pelvic floor repair. Among these cases there was a significant overall improvement in functional score (given as mean ± standard deviation) after both total pelvic floor repair (13.1±2.7vs. 6.6±4.5;P<0.001) and gluteus maximus transposition (13.8±3.8vs. 7.7±6.1;P<0.01), although no difference existed between the groups. There was no change in any of the physiologic measurements after either operation, and preoperative measurements did not identify patients likely to do badly. CONCLUSIONS: We conclude from these preliminary data that both total pelvic floor repair and gluteus maximus transposition significantly improve continence in women with postobstetric neuropathic fecal incontinence. Gluteus maximus transposition gives equivalent results to total pelvic floor repair. Neither procedure has any influence on anorectal physiologic parameters.Preliminary results presented at the Association of Surgeons of Great Britain and Ireland, Glasgow, Scotland, April 9 to 11, 1997.     

Open study of low-dose amitriptyline in the treatment of patients with idiopathic fecal incontinence

INTRODUCTION: Amitriptyline, a tricyclic antidepressant agent with anticholinergic and serotoninergic properties, has been used empirically in the treatment of idiopathic fecal incontinence with good results. METHODS: An open study was conducted to test the response to amitriptyline 20 mg daily for four weeks by 18 patients (2 males) of median age 66 years with idiopathic fecal incontinence. Incontinence scores, number of bowel movements, computerized ambulatory anorectal pressures, and pudendal nerve terminal motor latencies were evaluated before and after four weeks of therapy. Twenty-four control subjects (10 males) of median age 61 years were also assessed. RESULTS: Amitriptyline improved incontinence scores (median pretreatment score=16vs. median posttreatment score=3;P<0.001) and reduced the number of bowel movements per day (P<0.001). Amitriptyline also decreased the frequency (median pretreatment frequency=4.5 per hourvs. median immediate posttreatment frequency=1.2 per hour (P<0.05); control median frequency=0.3 per hour) and the amplitude of rectal motor complexes (median pretreatment rectal pressure=94 cm H₂Ovs. median immediate posttreatment rectal pressure=58 cm H₂O (P<0.05); control median rectal pressure=36 cm H₂O) and improved anal pressures during these events (P<0.001). CONCLUSIONS: Amitriptyline improved symptoms in 89 percent of patients with fecal incontinence. The data support that the major change with amitriptyline is a decrease in the amplitude and frequency of rectal motor complexes. The second conclusion is that drug increases colonic transit time and leads to the formation of a firmer stool that is passed less frequently. These in combination may be the source of the improvement in continence.Presented at the European Council of Coloproctology Biennial Meeting, Edinburgh, United Kingdom, June 17 to 19, 1997. Published in abstract form in theInternational Journal of Colorectal Disease 1997;12:143.     

Rectoanal motility in Crohn's disease patients

PURPOSE: It has been documented that Crohn's disease affects anorectal function when anorectal manifestations of the disease are present. The aim of this study was to investigate whether the presence of histologic lesions in rectal biopsy affected anorectal motility in patients with Crohn's disease but no evidence of macroscopic anorectal involvement. METHODS: Forty-one patients with documented Crohn's disease were included in the study. Twenty-one of them had no endoscopic or histologic lesions in the rectum, and 20 patients had a positive histology for Crohn's disease on rectal biopsy, with or without macroscopic or endoscopic involvement of the anorectum. All patients underwent a standard anorectal manometry, with an eight-channel, water-perfused catheter. RESULTS: Patients with positive rectal biopsy but no evidence of endoscopic rectal involvement had lower anal resting and squeeze pressures (76±16 standard deviationvs. 86±19 standard deviationP=0.002; 152±56 standard deviationvs. 192±52 standard deviationP<0.001, respectively), and a lower sphincter and high-pressure zone length (2.8±0.8 standard deviationvs. 3.2±0.8 standard deviationP=0.006; 1.7±0.6 standard deviationvs. 2±0.6 standard deviationP=0.005, respectively) compared with patients with negative rectal histology. Also, slow and ultra slow wave amplitude and ultra slow wave frequency were significantly lower (10±6 standard deviationvs. 13±7 standard deviationP=0.04; 17±16 standard deviationvs. 34±24 SDP=0.004; 0.9±0.8 standard deviationvs. 1.3±0.6 standard deviationP=0.05, respectively), rectal sensation more affected, and rectal compliance significantly reduced (7.4±1 standard deviationvs. 11.1±2.2 standard deviationP<0.001) in the former group of patients. Simultaneous presence of endoscopic and histologic lesions in the rectum was associated with further impairment of the anorectal function. CONCLUSION: Microscopic presence alone of Crohn's disease in the rectum appears to induce anorectal motility disorders. The synchronous presence of endoscopic rectal and macroscopic anal involvement is associated with further deterioration of anorectal function.     

Referral for anorectal function evaluation is indicated in 65% and beneficial in 92% of patients

AIM： To determine the indicated referrals to a tertiary centre for patients with anorectal symptoms, the effect of the advised treatment and the discomfort of the tests.
METHODS： In a retrospective study, patients referred for anorectal function evaluation （AFE） between May 2004 and October 2006 were sent a questionnaire, as were the doctors who referred them. AFE consisted of anal manometry, rectal compliance measurement and anal endosonography. An indicated referral was defined as needing AFE to establish a diagnosis with clinical consequence （fecal incontinence without diarrhea, 3^rd degree anal sphincter rupture, congenital anorectal disorder, inflammatory bowel disease with anorectal complaints and preoperative in patients for re-anastomosis or enterostoma, anal fissure, fistula or constipation）. Anal ultrasound is always indicated in patients with fistula, anal manometry and rectal compliance when impaired continence reserve is suspected. The therapeutic effect was noted as improvement, no improvement but reassurance, and deterioration. RESULTS： From the 216 patients referred, 167 （78%） returned the questionnaire. The referrals were indicated in 65%. Of these, 80% followed the proposed advice. Improvement was achieved in 35% and a reassurance in 57% of the patients, no difference existed between patient groups. On a VAS scale （1 to 10） symptoms improved from 4.0 to 7.2. Most patients reported no or little discomfort with AFE.
CONCLUSION： Referral for AFE was indicated in 65%. Beneficial effect was seen in 92%： 35% improved and 57% was reassured. Advice was followed in 80%. Better instruction about indication for AFE referral is warranted.     

Clinical and instrumental parameters in patients with constipation and incontinence: their potential implications in the functional aspects of these disorders

Purpose  The aims of this study were to evaluate several clinical and instrumental parameters in a large number of patients with constipation and incontinence as well as in healthy controls and discuss their potential implications in the functional aspects of these disorders. Methods  Eighty-four constipated and 38 incontinent patients and 45 healthy controls were submitted to a protocol based on proctologic examination, clinico-physiatric assessment, and instrumental evaluation. Results  Constipated and incontinent patients had significantly worse lumbar lordosis as well as lower rate in the presence of perineal defense reflex than controls. Constipated but not incontinent patients had a lower rate of puborectalis relaxation than controls. Furthermore, worse pubococcygeal tests and a higher rate of muscle synergies presence, either agonist or antagonist, were observed in both constipated and incontinent patients compared to controls. Conclusions  This study has demonstrated strong correlations between physiatric disorders and the symptoms of constipation and incontinence. Further studies designed to demonstrate a causal relationship between these parameters and the success of a specific treatment of the physiatric disorders on the proctology symptoms are warranted.     

Digital Rectal Examination of Sphincter Pressures in Chronic Anal Fissure Is Unreliable

PURPOSE Chronic anal fissure is said to be associated with internal sphincter hypertonia. However, an unknown proportion of fissures may be associated with normal or even low resting pressures and may subsequently be resistant to pharmacological treatments or at risk from surgical treatments, both of which aim to reduce sphincter hypertonia. This study investigated the ability of surgeons to detect low or normal pressure fissures by digital rectal examination.METHODS Patients with chronic anal fissure were assessed prospectively. The results of anal manometry performed on these patients were compared with digital rectal assessment of sphincter tone undertaken by a surgeon blinded to the manometry results.RESULTS Forty consecutive patients (21 male) with chronic anal fissure were studied. Twenty-two (55 percent) had normal maximum resting pressure and a further 3 (8 percent) had low pressures on anal manometry. On clinical assessment, only five (13 percent) patients were evaluated as having no anal hypertonia. Clinical assessment of anal tone correctly identified 14 of 15 patients with high manometric maximum resting pressure (sensitivity, 93 percent), yet detected only 4 of 25 patients with normal or low pressures (specificity, 16 percent). The positive predictive value of clinical assessment of anal tone was 40 percent and the negative predictive value, 80 percent.CONCLUSIONS The incidence of patients with chronic anal fissure without high manometric maximum resting pressure is higher than previously reported. The ability of surgeons to identify this group clinically was poor. It is reasonable to treat all patients primarily medically, and then selectively investigate by manometry those patients who fail medical therapy before considering lateral sphincterotomy.Presented at the Association of Coloproctology of Great Britain and Ireland Annual Conference, Edinburgh, United Kingdom, July 8 to 10, 2003.Reprints are not available.     

Effect of sacral nerve stimulation in patients with fecal and urinary incontinence

PURPOSE: Preliminary studies have shown improvement in fecal incontinence in several patients who received temporary or permanent stimulation. The purpose of this study was to report our experience in sacral nerve stimulation in the treatment of fecal incontinence and to target patients who would benefit most from stimulation. METHODS: Patients with fecal incontinence were studied clinically and manometrically before, during, and after temporary nerve stimulation. If temporary nerve stimulation was clinically successful, the patient was implanted and followed up for six months. RESULTS: Nine patients (6 female) with a mean age of 50.7 ± 12.3 years underwent temporary nerve stimulation. Temporary nerve stimulation was successful in eight patients, six of whom were implanted. Of the patients who could be evaluated, three of five had improved at the six-month follow-up visit, particularly in relation to the number of urgency episodes and delay in postponing defecation. All implanted patients had urinary symptoms. Urinary urgency was also improved by stimulation. During temporary nerve stimulation, the maximal squeeze pressure amplitude increased. After implantation, only the duration of maximal squeeze pressure seemed to improve. CONCLUSION: Sacral nerve stimulation can be used in the management of fecal incontinence, particularly in cases of urge fecal incontinence associated with urinary urgency. This study seems to confirm the effect of sacral nerve stimulation on striated sphincter function.Presented in part at the 7th United European Gastroenterology Week, Rome, Italy, November 13 to 17, 1999; the Brain-Gut 2000 Symposium, Toulouse, France, July 2 to 5, 2000; and the Second International Conference on the Pelvic Floor, Oxford, England, September 9 to 12, 2000.     

Impairment of anorectal function in diabetes mellitus parallels duration of disease

PURPOSE: The aim of this study was to investigate any possible relation between the severity of anorectal dysfunction in diabetes mellitus and duration of disease and presence of microangiopathy or neuropathy or both. METHODS: Standard multiport anorectal manometry was performed in 25 healthy control subjects (10 males; age (mean±1 standard deviation), 62±14 years) and 38 patients with diabetes mellitus. Patients were divided into two groups according to the duration of the disease: Group A (19 patients) with a duration less than 10 years (7.2±2.5; 8 males; age, 57±18) and Group B (19 patients) with a duration longer than 10 years (19.8±5.6; 6 males; age, 62±15). RESULTS: Results are reported as mean ± one standard deviation. Patients showed lower resting and squeeze anal pressures (P<0.01), impaired rectoanal inhibitory and anocutaneous reflexes, and reduced sensitivity in rectal distention (P=0.004) as compared with controls. In addition, Group B showed a significantly increased incidence of microangiopathy (P=0.04) and autonomic and peripheral neuropathy (P=0.002), significantly reduced basal and squeeze anal pressures (52±16vs. 64±24 mmHg;P=0.03 and 98±39vs. 124±54 mmHg;P=0.04, respectively), reduced amplitude of slow waves (7.3±3vs. 9.5±3.7 mmHg;P=0.03), anal leak in smaller rectal volumes (P=0.003), and reduced response of the anal sphincter at the anocutaneous reflexes (29±14vs. 39±14 mmHg;P=0.05) compared with Group A. The former group of patients exhibited a significantly higher incidence of fecal incontinence (P=0.008). CONCLUSION: Patients with long-standing diabetes mellitus have increased incidence of fecal incontinence and severely impaired function of both the anal sphincters and the rectum. These findings could be attributed to the increased incidence of microangiopathy and autonomic and peripheral neuropathy observed in this subset of diabetic patients.Presented at the United European Gastroenterology Week, Birmingham, United Kingdom, October 18 to 23, 1997.     

Effects of Caffeine on Anorectal Manometric Findings

Purpose  This study was designed to evaluate the effects of caffeine on anorectal function by anorectal manometry. Methods  Ten healthy subjects were studied. They drank 200 ml of water and later 200 ml of a solution that contained caffeine 3.5 mg/kg body weight. The anorectal manometric study was divided into three periods: basal, water, and caffeine; each period lasted 45 minutes. Results  After the ingestion of water, the basal anal sphincter pressure showed no change during the 45-minute recording, whereas after caffeine consumption the basal anal sphincter pressure increased at 10 minutes (P = 0.047) and 15 minutes (P = 0.037). The average basal anal sphincter pressure throughout the 45 minutes was significantly higher after caffeine ingestion than after water (P = 0.013). After caffeine intake, the maximum squeeze pressure increased significantly (P = 0.017) compared with the basal period. Both water and caffeine consumption caused a decrease in the rectal sensory threshold for the desire to defecate. Conclusions  Caffeine 3.5 mg/kg body weight in 200 ml of water resulted in stronger anal sphincter contractions both at basal period and during voluntary squeeze. The sensory threshold was also decreased, leading to an earlier desire to defecate. Caffeine consumption may result in an earlier desire to defecate, leading to defecation if the anal sphincter can relax voluntarily.