Anal Sphincter Function Research Articles

Experimental model of pudendal nerve innervation of a skeletal muscle neosphincter for faecal incontinence

Faecal incontinence is difficult to treat. A variety of reconstructive procedures has been described, but none is entirely satisfactory. This study evaluated the feasibility of cross-innervating a skeletal muscle neosphincter with the pudendal nerve in a canine model. Thirty dogs were rendered surgically incontinent (the pudendal nerve was cut and the external sphincter was partially excised). A neosphincter was then created using the semitendinosus muscle. In ten dogs pudendal nerve transposition (PNT) to the nerve to the semitendinosus muscle was performed. Ten dogs were given a dynamic neosphincter by inserting a pulse generator at 6 weeks. The remaining ten dogs served as controls with passive semitendinosus wraps. Anal manometry was performed before operation and monthly for 5 months. Muscle biopsies, performed at the initial operation and at 5 months, were stained for slow- and fast-twitch fibres, and were examined histologically. At 1 month, mean sphincter function was 32 per cent of the preoperative value in the control animals, 34 per cent in the PNT group and 27 per cent in the electrostimulation group; all dogs were incontinent. At 5 months the mean recovery of sphincter function was 42 per cent of the preoperative value in controls, 100 per cent in dogs with PNT (P < 0.001) and 63 per cent in dogs having electrostimulation (stimulator on) (P = 0.02). Six dogs with PNT had squeeze pressures equal to or greater than preoperative levels. At 5 months the ratio of slow to fast fibres was significantly greater in all dogs (control P = 0.01, PNT P < 0.005, electrostimulation P < 0.001). Use of the pudendal nerve to innervate a canine skeletal muscle anal wrap produced a functional anal sphincter that was superior to electrically stimulated and passive wraps.

Effect of anorectal eversion on long-term clinical outcome of restorative proctocolectomy.

Eversion of the rectum during restorative proctocolectomy with stapled ileal pouch-anal anastomosis (IPAA) remains a controversial surgical manoeuvre because of concern that it may impair anal sphincter function and adversely affect outcome. We have reviewed the long-term results in 41 patients whose operation included formation of a 20 cm J-pouch with stapled IPAA by the technique of rectal eversion. At median follow-up of 4 years (range 1-6 years), 4 pouches (10%) had been removed (2 for pelvic sepsis, 1 for rectovaginal fistula and 1 for Crohn's disease). In 34 patients with functioning pouches in situ, median stool frequency was 5 per 24 h (range 2-10). 11 patients (33%) regularly had to evacuate their pouch at night and 4 (12%) used antidiarrhoeal medication. No patients reported major incontinence; 2 (6%) had minor leakage, and in another 2 minor leakage had now ceased. 4 patients had had episodes of pouchitis. These favourable results offer no support for the contention that rectal eversion substantially worsens the long-term results of restorative proctocolectomy.

Extent of smooth muscle resection during mucosectomy and ileal pouch-anal anastomosis affects anorectal physiology and functional outcome.

In patients undergoing colectomy with ileal pouch-anal anastomosis, controversy exists regarding the necessity for and appropriate extent of rectal mucosal resection. Our aim was to assess histologically the extent of anorectal smooth muscle resected at the time of mucosal proctectomy and to correlate this with postoperative bowel and anal sphincter function. Surgical specimens of 79 patients undergoing colectomy, mucosal proctectomy, and ileal pouch-anal anastomosis were examined histologically in a blinded fashion, and the content of smooth muscle in the mucosal proctectomy specimens was scored. Degree of smooth muscle resection was correlated with postoperative anorectal manometry and with functional outcomes, including stool frequency and nocturnal leakage of stool after 3 and 12 months of follow-up. Degree of smooth muscle loss correlated with decreased resting pressure of the internal anal sphincter as early as three months after surgery (r = -0.26; P = 0.03), and the correlation was even stronger after 12 months (r = -0.37; P = 0.005). Decreases in resting pressure were related, in turn, to increased stool frequency at 12 months (r = 0.32; P = 0.02), but stool frequency was also inversely related to volume of the ileal pouch (r = -0.27; P = 0.05). Multivariate analysis confirmed that resting pressure and pouch volume were both significant determinants of stool frequency. The likelihood of nocturnal stool leakage at 12 months was primarily a function of stool frequency (P < 0.01) but also increased with patient age (P < 0.02). These findings indicate that loss of resting pressure of the internal anal sphincter can be correlated with the extent of smooth muscle resection during rectal mucosectomy and that these factors, in turn, correlate with increased stool frequency and a greater likelihood of nocturnal stool leakage. Consequently, an optimum functional result requires care in identifying and preserving maximum anorectal smooth muscle during mucosectomy.

Prediction of incontinence following low anterior resection for rectal carcinoma.

This study was performed to predict incontinence following low anterior resection for rectal cancer. Preoperatively, 21 patients were evaluated via patient history and a physical examination that included anal manometric studies. Six months postoperatively, repeat manometric studies and clinical evaluations were performed to assess the level of continence. Degree of continence was graded based on severity of the dysfunction and grade of the continence score. The formula used for predicted postoperative resting pressure is as follows: predicted postoperative resting pressure = 0.42 x preoperative resting pressure +1.56 x length of remaining rectum +12.37 (R2 = 0.58; P < 0.001). It was demonstrated that patients with low predicted postoperative resting pressures (< 30 mmHg) had incontinence, and those with high predicted postoperative resting pressures (> 35 mmHg) were continent. There were significant correlations between length of the remaining rectum and ratio of the decrease in maximum resting pressure (postoperative/preoperative maximum resting pressure; r = 0.63; P < 0.01). Continence following low anterior resection may be influenced by maximum resting pressure function of the internal anal sphincter; if it is injured during surgery, incontinence will occur. We may be able to foretell incontinence by using the predicted postoperative resting pressure formula, which is calculated by using preoperative resting pressure measurements and then determining the length of the remaining rectum.

Pharmacology of the internal anal sphincter and abnormalities in faecal incontinence.

Studies of anorectal physiology and in-vivo experiments on the innervation of the anorectum have provided considerable information about anorectal function. Additional information regarding the receptors and nerves involved in the control of the internal anal sphincter function has been obtained from in-vitro studies of isolated muscle strips of the internal anal sphincter.

Anorectal manometry in women with urinary stress incontinence

The aims of this prospective study were to determine the bowel function and the anal sphincter function in women with urinary stress incontinence by means of anorectal manometry and to look for manometric variables which could predict the development of surgery demanding genital prolapse after Burch colposuspension. During 1991-1992 twenty-one women with urodynamically proven genuine stress urinary incontinence were consecutively operated upon with the Burch colposuspension. No concomitant prolapse repair surgery was performed. Forty-four healthy subjects without anorectal disorders were used as controls. All subjects were investigated with anorectal manometry using a microtransducer catheter. A standardized questionnaire concerning bowel function was answered at interview. The manometry and interview were performed preoperatively and one year after the Burch colposuspension. According to the preoperative questionnaire, fecal incontinence was found in 62%, constipation in 38% and straining at defecation in 71%. There were no significant differences in any of the manometric parameters between the preoperative and the one-year postoperative assessment. The patients with prolapse operations after the colposuspension (n = 6) had a significantly lower anal squeeze pressure area (p = 0.029) preoperatively compared to the control subjects. The patients without prolapse surgery (n = 15) did not differ in manometric parameters from the control subjects. Bowel dysfunction is common in women with stress urinary incontinence. The women with low anal squeeze pressure area preoperatively are at risk for the development of genital prolapse after Burch colposuspension.

RECTOVAGINAL FISTULAS: Therapeutic Options

The management of RVF depends on size, location, and cause; anal sphincter function and overall health status of the patient; and the skill and judgment of the surgeon. Careful preoperative assessment of the fistula, surrounding tissues, and anal sphincter and exclusion of associated disease are essential. With thorough evaluation, thoughtful consideration of treatment options, and meticulous operative technique, patients can be assured of an optimal outcome. Success in treatment of patients with RVF should be measured not just in terms of successful closure of the fistula but also in terms of patient satisfaction with postoperative anal continence.

Disturbed Anal Sphincter Function Following Vaginal Delivery

Wynne, J. M.; Myles, J. L.; Jones, I.; Sapsford, R.; Young, R. E.; Hattam, A.; Cantamessa, S. E. Author Information

Original Article: Anorectal manometry in women with urinary stress incontinence

Objective. The aims of this prospective study were to determine the bowel function and the anal sphincter function in women with urinary stress incontinence by means of anorectal manometry and to look for manometric variables which could predict the development of surgery demanding genital prolapse after Burch colposuspension.Subjects. During 1991–1992 twenty-one women with urodynamicaiiy proven genuine stress urinary incontinence were consecutively operated upon with the Burch colposuspension. No concomitant prolapse repair surgery was performed. Forty-four healthy subjects without anorectal disorders were used as controls.Methods. All subjects were investigated with anorectal manometry using a microtransducer catheter. A standardized questionnaire concerning bowel function was answered at interview. The manometry and interview were performed preoperatively and one year after the Burch colposuspension.Results. According to the preoperative questionnaire, fecal incontinence was found in 62%, constipation ...

Disturbed anal sphincter function following vaginal delivery.

Recently interest in idiopathic (neurogenic) faecal incontinence has swung from denervation of the external anal sphincter to the internal sphincter. To evaluate the effects of vaginal delivery on the internal sphincter. 1372 mothers were studied antenatally and 1202 were accepted into the study. Sphincter pressures were measured antenatally, in the early postnatal period, and six to 10 weeks later in selected patients. 755 of 1202 subjects assessed antenatally were primiparous women and 447 multiparous women. Some 320 previous spontaneous vaginal deliveries (SVD) (mean 59 mm Hg) and 67 previous forceps deliveries (mean 58 mm Hg) had lower resting pressures than 755 primiparous women (mean 66 mm Hg) (p < 0.01). A total of 493 subjects were reassessed postnatally. There were 372 SVDs, 47 vacuum extractions, 20 forceps, and 54 caesarean deliveries. All vaginal deliveries but not caesarean sections dropped their resting anal pressures from antenatal values (p < 0.001). Some 227 first SVDs had a much greater fall than 145 subsequent SVDs. In 162 subjects who had undergone their first vaginal delivery and who were followed up there was some recovery but the resting pressures were still lowered at six to 10 weeks post partum. The first vaginal delivery causes a permanent lowering of resting anal pressures. The possible reasons for this are discussed.

The anal sphincter in idiopathic megarectum: effects of manual disimpaction under general anesthetic.

This study was designed to investigate the function and morphology of anal sphincters in patients with an idiopathic megarectum. A total of 17 patients were studied by anal endosonography and manometry when not impacted. Fourteen had previously been manually disimpacted under general anesthetic, and three had not. Nine of 14 patients in the former group, but none of the latter group, had disruption of one or both anal sphincter muscles on endosonography. Endosonographic changes were characteristic of those identified previously in patients following anal dilation. Low anal resting pressure, indicative of internal sphincter dysfunction, was found in a substantial proportion of patients with either an endosonographically intact or disrupted internal anal sphincter. Voluntary contraction increment, a reflection of external sphincter function, was normal in all patients. Manual disimpaction under general anesthetic appears to be associated with iatrogenic structural injury to the anal sphincters. In some patients, this may contribute to sphincter weakness. This damage may contribute to the incontinence experienced by patients with a dilated rectum.

Continence is improved after the ripstein rectopexy

This study was undertaken to evaluate anal manometric changes after Ripstein's operation for rectal prolapse and rectal intussusception and to study the clinical outcome following the operation, with special reference to anal incontinence. Forty-two patients with rectal prolapse or rectal intussusception were subjected to anorectal manometry preoperatively and seven days and six months postoperatively. A detailed history was obtained from each patient preoperatively and six months postoperatively. Preoperatively, patients with rectal intussusception had higher maximum resting pressure (MRP) (52+/- 23 mmHg) than patients with rectal prolapse (34 +/- 20 mmHg; P < 0.01). In the group of patients with rectal prolapse, there was a postoperative increase in MRP after six months (P < 0.001) but not after seven days. Maximum squeeze pressure (MSP) did not increase. Neither MRP nor MSP increased postoperatively in patients with internal rectal procidentia. Continence was improved postoperatively both in patients with rectal prolapse (P < 0.01) and rectal intussusception (P < 0.01). There was no postoperative increase in rectal emptying difficulties. Ripstein's operation often improved anal continence in patients with rectal prolapse and rectal intussusception. This improvement was accompanied by increased MRP in patients with rectal prolapse, indicating recovery of internal anal sphincter function. No postoperative increase in MRP was found in patinets with rectal intussusception. This suggests an alternate mechanism of improvement in patients with rectal intussusception.

Level of highest mean resting pressure segment in the anal canal

Even with the development of new technologies, the mechanism of fecal continence is still not completely understood. This study evaluates the relative position of the highest mean resting pressure (HMRP) in the anal canal and its correlation with function in incontinent patients and in controls. Sixteen incontinent patients (mean age, 47.1 +/- 13.9 (range, 18-63) years; 12 female) and 16 controls (mean age, 35.4 +/- 8.7 (range, 24-58) years; 12 female) were studied using a water-perfused eight-port radial catheter computer-assisted vectromanometry. Position of the HMRP was analyzed in relation to the anal verge (D1) and to the proximal functional border of the anal canal (D2). Controls had HMRP located more distally in the anal canal, because D2 was significantly higher than D1 (mean, 3.45 +/- 0.75 vs. 1.81 +/- 0.63 cm; p + 0.001). For incontinent patients, D1 and D2 were similar (mean, 1.86 +/- 0.75 vs. 2.08 +/- 1.11 cm; not significant). Comparison of the relative position of the HMRP between patients and controls showed a more proximal location for incontinent patients than controls (mean, 49.1 +/- 12.1 percent vs. 35.4 +/- 10.2 percent; p = 0.002). Position of the HMRP is significantly more proximal for incontinent patients than for controls, and measurement of the distance from the anal verge to the HMRP in relation to the full length of the anal canal may represent another way to quantitatively assess anal sphincter function.

Squamous cell carcinoma of the anal margin treated with radiotherapy

Squamous cell carcinoma of the anal margin is relatively rare. We present a series of patients treated with radiotherapy alone or combined with concomitant chemotherapy at our institution and review the pertinent literature. Ten patients with AJCC T2N0 and T3N0 squamous cell carcinoma of the anal margin were treated with radiotherapy alone or radiotherapy plus chemotherapy at the University of Florida between 1979 and 1993. All patients had a follow-up for at least 2 years, and no patient was lost to follow-up. All ten patients have remained continuously disease free after treatment. Three patients died of intercurrent disease at 29, 37 and 113 months after treatment. The remaining seven patients were alive and disease-free from 24 to 143 months after radiotherapy. No patient experienced a major complication and all retained a functional anal sphincter. Based on our experience and a review of the literature, superficial, well to moderately differentiated, T1 and T2 cancers may be successfully treated with radiotherapy alone or a local excision. More advanced lesions are best treated with combined radiotherapy and concomitant chemotherapy. Abdominoperineal resection should be reserved for those presenting with faecal incontinence and those with locally recurrent disease after previous radiotherapy.

148 Curative management of rectal adenocarcinoma with radiotheraphy alone: A series of 250 cases

This report pools the results of two institutions using since 1970 the strategies developed in Lyon by Jean Papillon. (1) <i>Low and mid rectum T1 and selected T2 well differentiated adenocarcinoma</i> treated with intrarectal contact X-ray (ICRT) and interstitial brachytherapy (IBT). Since 1970, 200 patients (113 T1, 87 T2) were treated in Dijon and Lyon-Sud. Transrectal ultrasonography has been used for staging since 1987. Failures rates (unlimited follow-up) are local in 4.5% (T1) and 19.5% (T2), nodel in 0.9% (T1) and 9% (T2), metastatic in 3.5% (T1) and 12.5% (T2). Salvage treatment was successful in 20/24 pelvic failures. Ultimate pelvic control was obtained in 189/200 (94.5%) with preservation of a functional anal sphincter in 95% of PTS with pelvic control. No severe complication occurred. (2) <i>Low and mid rectum T2 and T3 adenocarcinoma</i> treated with external radiotherapy (30–39 Gy in 10–13 fro and 14–17 days to the posterior pelvis. Concomitantly, ICRT delivers 60–80 Gy in 2–3 fr. After a 6- to 8-week rest period, a 20–30 Gy boost is delivered by IBT Fifty patients were treated (34 T2, 16 T3). Twelve out of 50 (24%) had a local failure (5/12 with a subsequent surgical salvage treatment) resulting in an 82% ultimate control rate with a functional sphincter. G2 complications occurred in 16% (rectorragia/ulcer). A single patient had a G3 necrosis.

Effect of lateral sphincterotomy on internal anal sphincter function. A computerized vector manometry study.

This study was designed to investigate the effect of lateral sphincterotomy on internal anal sphincter function in patients with chronic anal fissure. Using an eight-channel perfusion catheter and computerized data analysis, a prospective manometric study was performed on patients with chronic anal fissure undergoing lateral sphincterotomy (LS). Mean resting pressure (MRP) in patients with anal fissure (85.1 mmHg) was significantly higher (P = 0.012) than control subjects (63.3 mmHg). One week following LS there was a significant reduction in MRP (50.0 mmHg; P = 0.0014), and this was maintained when reassessed five weeks later (MRP = 56.4 mmHg; P = 0.0019). There was no significant difference in coefficient of variation (a measure of the degree of manometric asymmetry of the anal canal) in the control group (mean, 8.9 percent) and in patients with anal fissure (mean, 7.7 percent; P = 0.43). LS created a significant increase in anal canal resting manometric asymmetry when assessed at one (mean, 17.3 percent; P = 0.0013) and six weeks (mean, 11.7 percent; P = 0.027) after the procedure. LS produces a global and symmetric decrease in anal canal resting pressure. In addition, it produces a significant increase in manometric asymmetry of the resting anal canal by creating a detectable segmental defect.

Hyperglycemia alters perception of rectal distention and blunts the rectoanal inhibitory reflex in healthy volunteers

Background/Aims: Acute hyperglycemia has been shown to alter gastrointestinal motility. The effects of hyperglycemia on rectal afferent neural and anal sphincter function were studied. Methods: Perception of rectal balloon distention, pressure-volume relationships, volumes necessary to induce reflex internal anal sphincter relaxation, resting anal sphincter pressure, and maximal anal sphincter squeeze pressure were measured under basal, hyperglycemic clamp, and euglycemic, hyperinsulinemic clamp conditions in 9 healthy volunteers. Results: Hyperglycemic clamping (258 ± 14 mg/dL) significantly blunted threshold perception and the urge to defecate in response to rectal distention without altering perception of maximally tolerated distention. In contrast, euglycemic, hyperinsulinemic clamping had no effect on perception of rectal distention. Rectal pressure-volume relationships after hyperglycemic clamping were unchanged compared with basal conditions. Hyperglycemic clamping caused a significant increase in the distention necessary to induce the rectoanal inhibitory reflex. This effect was not observed under euglycemic, hyperinsulinemic clamp conditions. Hyperglycemia did not significantly affect resting internal anal sphincter pressure or maximal external anal sphincter squeeze pressure. Conclusions: Acute hyperglycemia but not secondary hyperinsulinemia reduces sensation of rectal distention and blunts the onset of the rectoanal inhibitory reflex, suggesting effects both on visceral afferents projecting to the cortex and intrinsic afferents mediating local reflex activity.

Direct electrostimulation of sacral spinal nerves within the scope of the diagnosis of anorectal function

A technique is demonstrated to evaluate the functional relevance of the sacral spinal nerves regarding anal sphincter function. Sacral spinal nerves S2, S3, S4 can be reached selectively for electrical stimulation by a dorsal approach through the sacral foramina. Electrical stimulation of S3 and S4 results in visible contraction of the different striated muscular anal sphincter components and in an increase of anal canal closure pressure. These effects differ among individuals. Thus, the functional relevance of each single sacral spinal nerve on the striated muscular anal sphincter can be tested specifically.

Reconstruction of urinary andgastrointestinal tracts in total pelvic exenteration: Experience at columbia-presbyterian medical center

To examine the effectiveness of and complications from total pelvic exenteration (TPE) with maintenance of urethral and anal sphincter function for locally invasive tumors of the pelvis. A retrospective review of 4 patients who have undergone TPE with urethral and anal sphincter preservation at Columbia-Presbyterian Medical Center in the last 2 years was performed with attention to perioperative morbidity and mortality, disease-free status, and need for further operative procedures. Two patients had colorectal adenocarcinoma, 1 had squamous cell carcinoma of the cervix, and 1 had prostate sarcoma. All had urinary tract reconstruction with orthotopic neobladder creation, and 3 of 4 had primary low rectal anastomoses for gastrointestinal reconstruction. One patient underwent creation of a J rectal pouch. One of 4 patients had received radiation therapy for the disease prior to surgery. There was no operative or perioperative mortality. Two of 4 patients required reoperation, 1 in the immediate postoperative period for repair of a left ureteral stricture, and the other 13 months postoperatively for repair of a rectal-neobladder fistula. With a mean follow-up of 25 months (range, 21 to 43 months), 3 of 4 patients are alive and free of disease. All living patients are continent of urine and 2 of 3 are continent of stool. Our experience confirms that TPE can be effective in controlling a variety of locally advanced pelvic tumors and can be performed in conjunction with simultaneous genitourinary and gastrointestinal reconstruction with minimal morbidity.

Recovery of anal sphincter function after the ileoanal reservoir procedure in patients over the age of fifty

This study was undertaken to postoperatively assess the progression of anal sphincter function and clinical outcome in patients > or = 50 years old (Group I) compared with those < 50 years old (Group II). Clinical data were assessed after ileostomy closure by a questionnaire. These data were compiled to obtain an incontinence score, which ranged from 0 (perfect continence) to 20 (total incontinence). Anorectal manometry was performed preoperatively (MN1) and postoperatively, before (MN2) and after (MN3) ileostomy closure. Wilcoxon and paired t-test were used to compare the clinical and functional results, respectively. Group I consisted of 22 patients (mean age, 56 years) and Group II, 50 patients (mean age, 32 years). No differences were found relative to either preoperative pressures or clinical outcome. However, both the mean and high resting pressures were significantly lower in Group I at the MN2 examination. The effect on anal sphincters of ileoanal reservoir in patients over the age of 50 years is similar to that noted in younger patients. Transient impairment of internal anal sphincter function observed after ileoanal reservoir is more severe in older patients (P = 0.01). However, as in younger patients, it does completely recover after ileostomy closure.