Fecal incontinence after minor anorectal surgery

PURPOSE: Fecal leakage after open lateral internal anal sphincterotomy for chronic anal fissure is common, but underreported. The aim of this study was to prospectively assess the physiologic and morphologic effects of sphincterotomy, comparing continent and incontinent patients after surgery. This group was further compared with an unselected group of patients presenting with incontinence after hemorrhoidectomy. METHODS: Between January 1997 and June 1999, 23 patients were prospectively followed up through internal sphincterotomy with conventional and vector volume anorectal manometry, parametric assessment of the rectoanal inhibitory reflex, and endoanal magnetic resonance imaging. Fourteen continent patients were compared with 9 incontinent postoperative cases, 9 patients referred with incontinence after hemorrhoidectomy, and 33 healthy volunteers without anorectal disease. RESULTS: Significant differences were noted between continent and incontinent postsphincterotomy cases for all resting conventional and vector volume parameters and for some squeeze parameters. Although there was a significant reduction in postoperative high pressure zone length at rest, there were no differences between the postoperative groups. There was an increase in sphincter asymmetry of 6.7 percent (± 3.5 percent) in incontinent postsphincterotomy patients and a decrease of 2.8 percent (± 3.2 percent) in continent cases. Significant differences were noted for resting parameters between incontinent postsphincterotomy and posthemorrhoidectomy patients, with a higher resting sphincter asymmetry in the latter group. The area under the rectoanal inhibitory curve was smaller in postsphincterotomy incontinent patients when compared with continent cohorts over the distal and intermediate sphincter zones at rest with a reduced latency of inhibition. There was no difference in the magnetic resonance images of the sphincterotomy site between incontinent and continent postsphincterotomy cases and no posthemorrhoidectomy case had evidence of sphincteric damage. CONCLUSION: There are complex significant differences in the postoperative physiology of patients undergoing lateral internal sphincterotomy who become incontinent when compared with those who maintain continence. These physiologic changes are not reflected in detectable morphologic sphincteric differences. It is unknown whether these changes predict for long-term incontinence, and it is suggested that postoperative incontinence after minor anorectal surgery is not necessarily related either to a preexisting sphincter defect or inadvertent intraoperative sphincter injury.This work was performed at the Hammersmith Hospital London Imperial College School of Science Technology and Medicine. Presented at the Section of Coloproctology at the Royal Society of Medicine, London, United Kingdom, March 22, 2000, at the Annual Meeting of the Israeli Society of Colon and Rectal Surgery, Nazareth, Israel, September 24 to 27, 2000, and as a poster at the Congress of the European Council of Coloproctology, Prague, Czech Republic, April 29 to May 2, 2001 (winner of the poster prize).     

Anal endosonographic evaluation after closed lateral subcutaneous sphincterotomy

PURPOSE: The present study was undertaken to evaluate anal endosonographic results of the transverse and longitudinal extent of internal anal sphincter division after closed lateral subcutaneous sphincterotomy and its relationship to outcome with respect to anal fissure recurrence and postoperative anal incontinence. METHODS: Ten patients selected for symptomatic anal fissure recurrence (mean follow-up, 10.9 months) and 41 asymptomatic control patients (mean follow-up, 15.5 months) were reviewed by anal endosonography after closed lateral subcutaneous sphincterotomy. Clinical evaluation was focused on anal fissure recurrence and postoperative anal incontinence. The anal endosonographic study involves serial radial images of the distal, proximal, and midanal canal. RESULTS: In 32 patients in whom a complete internal sphincter defect was identified, 31 (75.6 percent) were from the control group and only 1 patient (10 percent) was from the recurrence group (P<0.001). In 19 patients, an incomplete internal sphincter defect was identified; 10 (24.4 percent) were from the control group (residual median size, 1.8 mm; contralateral, 2.5 mm) and 9 patients (90 percent) were from the recurrence group (P=0.001; residual median size, 1.4 mm; contralateral, 2.2 mm). Ten patients (19.6 percent) were incontinent for gas and three patients (5.9 percent) for liquid feces, without significant differences between groups. CONCLUSIONS: Anal endosonography is a useful method for evaluating the anatomic effectiveness of closed lateral subcutaneous sphincterotomy. An incomplete sphincterotomy is associated with significant symptomatic anal fissure recurrence.Poster presentation at the meeting of The American Society of Colon and Rectal Surgeons, Philadelphia, Pennsylvania, June 22 to 26, 1997.     

Perineal body measurement improves evaluation of anterior sphincter lesions during endoanal ultrasonography

Endoanal ultrasonography has become an important tool in the evaluation of patients with anal incontinence. However, the extent of anterior defects is sometimes difficult to quantitate during endoanal ultrasonography. PURPOSE: This study was designed to evaluate perineal body measurement during endoanal ultrasonography in assessing patients with obstetric anal sphincter injuries. METHODS: Forty-two patients with anal incontinence because of obstetric sphincter injuries and 13 asymptomatic subjects were investigated with endoanal ultrasonography. Sphincter muscle thickness, sphincter defects, and perineal body were measured. Perineal body measurement was performed by inserting a finger, held gently against the posterior vaginal wall, into the vagina and measuring the distance between the inner surface of the internal sphincter and the ultrasonographic reflection of the finger. RESULTS: All patients had anterior sphincter lesions of varying extent. Mean size of internal sphincter lesions was 146°, and mean size of external sphincter lesions was 107° (P<0.001). Perineal body measurement was performed without difficulty in all patients and subjects. Perineal body measurement (mean ± standard deviation) was 6±2 mm in patients and 12±3 mm in asymptomatic subjects (P<0.001). Ninety-three percent of patients had perineal body measurement <-10 mm, and 70 percent of asymptomatic subjects had perineal body measurement >10 mm. Digital delineation of the perineal body during endoanal ultrasonography improved the visualization of sphincter lesions in 74 percent of patients. CONCLUSIONS: Digital delineation of the perineal body during endoanal ultrasonography improved the visualization of sphincter lesions in the majority of patients. Perineal body measurement is performed without difficulty and is a good predictor of anterior sphincter lesions. Use of this technique improves visualization of sphincter lesions.Read at the meeting of The American Society of Colon and Rectal Surgeons, Philadelphia, Pennsylvania, June 22 to 26, 1997.     

Volume Measurements of the Anal Sphincter Complex in Healthy Controls and Fecal-Incontinent Patients With a Three-Dimensional Reconstruction of Endoanal Ultrasonography Images

OBJECTIVES The aim of this study was to determine sphincter volume, length, and external anal sphincter thickness in healthy controls and fecal incontinent patients by use of a three-dimensional reconstruction of endoanal ultrasonography images.METHODS Forty-four controls (15 males, 15 females, and 14 parous females) and 28 incontinent parous females (with and without a sphincter defect) were studied. Internal anal sphincter, external anal sphincter and puborectalis volume, sphincter length, and external anal sphincter thickness were measured. Intraobserver and interobserver variability were assessed. Anal pressure profile was also determined.RESULTS Internal anal sphincter and external anal sphincter volumes were larger in males than in females (P = 0.001 and P = 0.04), and external anal sphincter volume was smaller in parous females but this was not significant (P = 0.084). Anterior sphincter length was longer in males (P = 0.004) and shorter in parous females (P = 0.06). Males had a larger anterior external anal sphincter thickness (P = 0.018); parity made no difference. Sphincter volumes were not smaller in incontinent females. Incontinent females with a sphincter defect had a shorter anterior sphincter length than that of continent (P = 0.001) and incontinent females without a sphincter defect (P < 0.001). Anterior external anal sphincter thickness was smaller in incontinent females with a sphincter defect (P = 0.006), and posterior and right external anal sphincter thickness was smaller in incontinent females without a sphincter defect (P = 0.02 and P = 0.03). Intraobserver variability was seen for internal anal sphincter volume and sphincter length, but there was no interobserver variability. Correlation between anal pressures and endoanal ultrasonography measurements was poor.CONCLUSIONS Differences in anal sphincter volumes are seen for gender but not for parity. Fecal incontinence is not associated with loss of sphincter volume. However, anterior sphincter length and external anal sphincter thickness are smaller.Presented at the meeting of the Netherlands Society of Gastroenterology, Veldhoven, The Netherlands, March 20 to 21, 2003 and October 2 to 3, 2003, and at the Digestive Disease Week, New Orleans, Louisiana, May 15 to 20, 2004.R. L. West was supported by a grant from Janssen-Cilag B.V., The Netherlands.Reprints are not available.     

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

PURPOSE: The aim of this study was to test the hypothesis that a delay in pudendal nerve conduction as measured by pudendal nerve terminal motor latency should be associated with atrophy of the external anal sphincter as measured using endoanal ultrasound. METHODS: Sixty-two adult females (median age, 58.9 (range, 22–88) years) presenting for evaluation of fecal incontinence with no evidence of an external anal sphincter tear on ultrasound were recruited. Ultrasound was performed with a 7.5-MHz radial rotating axial endoprobe in the left lateral position. Four measurements were made in the transverse plane—the external anal sphincter thickness in the midanal canal at the 6 o'clock and 9 o'clock positions, the internal sphincter at the 9 o'clock position, and the external anal sphincter in the low canal at the 9 o'clock position. Pudendal nerve terminal motor latency was measured using a transrectal nerve stimulation technique with measurement of the evoked muscle response. RESULTS: Although there was a trend toward thinner external sphincter muscles in those with bilateral prolonged pudendal nerve terminal motor latency, independent sample t-tests and Pearson correlation coefficients showed no statistically significant relationship (right pudendal nerve terminal motor latency:P=0.083, 0.184, 0.128, 0.910;r=0.228, 0.175, –0.201, –0.015; left pudendal nerve terminal motor latency:P=0.946, 0.276, 0.510, 0.123;r=–0.009, –0.143, –0.087, –0.201). CONCLUSIONS: No statistically significant relationship between ultrasound-measured anal sphincter muscle thickness and pudendal nerve terminal motor latency was identified. Although a trend was suggested that could be further evaluated by a study with a larger sample size and a control group with asymptomatic patients, the small differences in muscle thickness involved and the difficulties in measurement suggest that the establishment of clinically useful ultrasound criteria for the detection of the neuropathic anal sphincter complex is unlikely.     

Faecal incontinence after internal sphincterotomy for anal fissure

Minor defects in continence following open lateral sphincterotomy are relatively common. This study prospectively assessed 28 patients undergoing lateral sphincterotomy for chronic anal fissure. There were substantial differences in both resting and squeeze anal pressures and vector volumes in the incontinent cohort when compared to the continent post-operative cases. Mean preoperative high pressure zone was 37.6 mm, significantly higher than the postoperative value of 17.0 mm (p < 0.001). There was a significant difference in percent asymmetry of the anal canal at rest between incontinent and continent post-sphincterotomy cases, with a 6.7% increase in the former group and a 3.1% fall in the latter group (p < 0.001). It is unknown whether these changes are predictive for long-term continence. Received: 28 January 2000 / Accepted in revised form: 14 March 2000     

Prospective study of the extent of internal anal sphincter division during lateral sphincterotomy

PURPOSE: The aim of lateral internal anal sphincterotomy when treating anal fissure is to divide the distal one-third to one-half of the internal anal sphincter. This study aimed to evaluate prospectively the extent of disruption to the internal anal sphincter following lateral anal internal sphincterotomy and also to establish the prevalence of symptoms of anal incontinence in these patients. METHODS: Fifteen patients with anal fissure (ten females and five males) had bowel symptoms assessed and anal endosonography performed preoperatively and two months after lateral internal anal sphincterotomy. RESULTS: Anal endosonography was normal preoperatively in all but two females who had anterior external sphincter defects (presumedly from previous obstetric trauma). Postoperatively, apart from one male in whom no defect could be identified, all had an internal anal sphincter defect corresponding to the site of lateral internal anal sphincterotomy. In nine of the ten females, the defect involved the full length of the internal anal sphincter, but in the other four males, the defect involved the distal internal anal sphincter only. All were continent preoperatively, but after lateral internal anal sphincterotomy, three females became incontinent to flatus (two of whom had a preoperative external sphincter defect). CONCLUSION: In contrast to lateral internal anal sphincterotomy in males, division of the internal anal sphincter in most females tends to be more extensive than intended. This is probably related to their shorter anal canal. In some females, lateral internal anal sphincterotomy may compromise sphincter function and precipitate anal incontinence, particularly in the presence of other sphincter defects. Care should be exercised especially in the presence of previous obstetric trauma, as internal anal sphincter division may further compromise sphincter function.     

Evidence of electromechanical dissociation of the internal anal sphincter in idiopathic fecal incontinence

PURPOSE: This study was designed to evaluate the relationship between internal sphincter electromyographic frequency and ambulatory anal pressures in order to clarify the pathophysiology of internal anal sphincter dysfunction in fecal incontinence. METHODS: Seventytwo patients of median age 55 years (range, 24–75; 63 females) with neurogenic fecal incontinence and 33 normal subjects of median age 48.5 years (range, 25–74; 21 females) underwent fine-wire anal sphincter electromyography and anal manometry. RESULTS: The median internal anal sphincter electromyographic frequency was incontinent 0.25 Hz (0.2–0.34) and the control was 0.44 Hz (0.36–0.55;P<0.03). Ambulatory resting pressures were incontinent median 54 cm of H ₂ O (34–68 cm of H ₂ O) and control 94 cm of H ₂ O (72–102;P<0.01). Internal sphincter electromyographic frequency correlated with anal resting pressures in both groups (P<0.002). Internal sphincter electromyographic silence not attributable to electrode movement or the rectoanal inhibitory reflex, lasting 0.5 to 4 minutes occurred in all but two of the incontinent patients. The anal pressure during this period did not significantly change (P>0.1). No recruitment of the external sphincter or puborectalis was noted during these episodes. Such electromechanical dissociation was not seen in the control group. The frequency of transient internal sphincter relaxation was 4 (ranges 2–6) per hour in controls and 8 (ranges, 6–12) per hour in incontinent patients (P<0.01). Rectal pressures did not exceed midanal pressures in any of the controls but did in all of the incontinent patients on at least one occasion per hour in the incontinent group. CONCLUSION: Internal anal sphincter activity exhibits electromechanical dissociation and relaxes abnormally in incontinent patients.Supported by a separate equipment grant from the Scottish Hospital Endowment Research Trust.Read at the meeting of The American Society of Colon and Rectal Surgeons, San Francisco, California, June 7 to 12, 1992.     

The Utility of Pudendal Nerve Terminal Motor Latencies in Idiopathic Incontinence

Purpose Pudendal nerve terminal motor latency testing has been used to test for pudendal neuropathy, but its value remains controversial. We sought to clarify the relationship of pudendal nerve terminal motor latency to sphincter pressure and level of continence in a cohort of patients with intact anal sphincters and normal pelvic floor anatomy. Methods We reviewed 1,404 consecutive patients who were evaluated at our pelvic floor laboratory for fecal incontinence. From this group, 83 patients had intact anal sphincters on ultrasound and did not have internal or external rectal prolapse during defecography. These patients were evaluated by pudendal nerve terminal motor latency testing, a standardized questionnaire, and anorectal manometry, which measured resting and squeeze anal pressures. Incontinence scores were calculated by using the American Medical Systems Fecal Incontinence Score. Values were compared by using the Fisher’s exact test and Wilcoxon’s rank-sum test; and significance was assigned at the P < 0.05 level. Results 1) Using a 2.2-ms threshold, 28 percent of patients had prolonged pudendal nerve terminal motor latency unilaterally and 12 percent bilaterally. 2) At a 2.4-ms threshold, 18 percent of patients had prolonged pudendal nerve terminal motor latency unilaterally and 8 percent bilaterally. 3) Bilaterally prolonged pudendal nerve terminal motor latency was significantly associated with decreased maximum mean resting pressure and increased Fecal Incontinence Score, but not decreased maximum mean squeeze pressure, at both 2.2-ms and 2.4-ms thresholds. 4) Unilaterally prolonged pudendal nerve terminal motor latency was not associated with maximum mean resting pressure, maximum mean squeeze pressure, or fecal incontinence score at either threshold. Conclusions The majority of incontinent patients with intact sphincters have normal pudendal nerve terminal motor latency. Bilaterally but not unilaterally prolonged pudendal nerve terminal motor latency is associated with poorer function and physiology in the incontinent patient with an intact sphincter. Presented at the meeting of The American Society of Colon and Rectal Surgeons, Dallas, Texas, May 8 to 13, 2004. Reprints are not available.     

Anorectal sensory and motor function in neurogenic fecal incontinence. Comparison between multiple sclerosis and diabetes mellitus

We measured anorectal sensory and motor function in 11 patients with multiple sclerosis and fecal incontinence, 11 continent patients with multiple sclerosis, 10 diabetics with fecal incontinence, and 12 healthy control subjects. The threshold volume at which patients with multiple sclerosis and fecal incontinence experienced rectal sensation was higher than that in healthy controls (42.7 +/- 6.2 mL vs. 13.3 +/- 2.8 mL; P less than 0.01) and was similar to that in incontinent diabetics (36.5 +/- 5.7 mL). Patients with multiple sclerosis and incontinent diabetics also showed increased thresholds of phasic external sphincter contraction compared with controls (P less than 0.05). Diabetics with incontinence had reduced resting and maximal voluntary anal sphincter pressures compared with controls (P less than 0.05), whereas patients with multiple sclerosis and incontinence showed only decreased maximal voluntary anal sphincter pressures (P less than 0.01 vs. controls and diabetics). Incontinent patients with multiple sclerosis also required smaller volumes of rectal distention to inhibit internal sphincter tone compared with diabetics and controls (P less than 0.01). Decreased maximal voluntary squeeze pressures were less severe in continent patients with multiple sclerosis than in incontinent patients with multiple sclerosis. We conclude that impaired function of the external anal sphincter and decreased volumes of rectal distention to inhibit the internal anal sphincter or both may contribute to fecal incontinence in multiple sclerosis. In addition, increased thresholds of conscious rectal sensation in some incontinent patients with multiple sclerosis and diabetes mellitus may contribute to fecal incontinence by impairing the recognition of impending defecation.     

Fatigability of the External Anal Sphincter in Anal Incontinence

INTRODUCTION Anal incontinence commonly results from external anal sphincter dysfunction. The muscle is routinely assessed by anorectal physiology studies. Fatigability is not routinely measured but should be an important factor in the maintenance of continence. The fatigue rate index has been developed to address this. The purpose of this study was to investigate the fatigability of the external anal sphincter in incontinent patients compared with that in controls and to determine its correlation with symptom severity and pudendal nerve terminal motor latency measurement.METHODS Forty-two patients with anal incontinence (33 female, 9 male) and 20 control patients (17 female, 3 male) were studied. As part of anorectal physiology studies, manometry was measured by a station pull-through technique with a closed-system microballoon. After a rest period of one minute, fatigue was measured over a 20-second squeeze at 1.5 cm in the anal canal with two consecutive readings separated by a further one-minute rest period. The fatigue rate index was calculated from the maximum squeeze pressure and fatigue rate. A validated symptom severity scoring system was used to assess symptomatology in patients with anal incontinence.RESULTS No difference was detected in demographic factors between the two groups. The fatigue rate index was significantly different between the control and incontinent groups (1.85 vs. 0.67 minutes, P = 0.001). No other factors were significantly different between the two groups (maximum squeeze pressure, 89.1 vs. 79 cm H₂O, P = 0.42; fatigue rate, –85.8 vs. –101.2 cm H₂O/min, P = 0.62). The fatigue rate index demonstrated a significant correlation with symptom score (r = –0.44, P = 0.005). The fatigue rate index did not correlate with latency measurement.CONCLUSIONs A significant difference was detected in the fatigue rate index between incontinent and control patients. The Fatigue Rate Index demonstrated a significant correlation with symptom severity score and it may be a useful discriminating measure of external anal sphincter function.Poster presentation at the meeting of The American Society of Colon and Rectal Surgeons, Chicago, Illinois, June 3 to 8, 2002, and at the meeting of the Association of Coloproctology of Great Britain and Ireland, Harrogate, United Kingdom, July 2 to 5, 2002.     

Long-term results of lateral internal sphincterotomy for chronic anal fissure with particular reference to incidence of fecal incontinence

PURPOSE: Lateral internal sphincterotomy is the procedure of choice for chronic anal fissure because it relieves symptoms and heals the fissure in nearly all patients. However, there is evidence that fecal incontinence complicates lateral internal sphincterotomy. The aim of this study was to examine the outcome of lateral internal sphincterotomy in terms of fissure healing and incidence of fecal incontinence. METHODS: Between 1984 and 1996, 585 patients underwent lateral internal sphincterotomy and were surveyed by questionnaire. Eighty-three percent (487/585) responded. The mean follow-up was 72 (range, 6–145) months. RESULTS: Fissures had healed by a median of three weeks after surgery in 96 percent of patients. Recurrent fissures occurred in 8 percent. Two thirds of the recurrent fissures healed on conservative management alone. Ninety-eight percent of patients were satisfied with the outcome of surgery, but some degree of fecal incontinence occurred in fully 45 percent of patients at some time in the postoperative period. Incontinence occurred in 53.4 percent of women and 33.3 percent of men (P<0.05). Incontinence to flatus, mild soiling, and gross incontinence occurred in 31, 39, and 23 percent of patients, respectively. However, by the time of survey (a mean of >5 years after lateral internal sphincterotomy) 6 percent reported incontinence to flatus, 8 percent had minor fecal soiling, and 1 percent experienced loss of solid stool. Importantly, only 3 percent of patients stated that incontinence had ever affected their quality of life. CONCLUSION: Although lateral internal sphincterotomy heals and relieves symptoms of chronic anal fissure in nearly all patients (96 percent), incontinence occurs frequently. Most episodes of incontinence are indeed minor and transient, but in a small subgroup, incontinence seems to be permanent.Read at the meeting of The American Society of Colon and Rectal Surgeons, Philadelphia, Pennsylvania, June 22 to 26, 1997.     

Clinical, Manometric, and Ultrasonographic Results of Pneumatic Balloon Dilatation vs. Lateral Internal Sphincterotomy for Chronic Anal Fissure: A Prospective, Randomized, Controlled Trial

Purpose This prospective, randomized, controlled trial was designed to compare the clinical, functional, and morphologic results of pneumatic balloon dilatation with lateral internal sphincterotomy for the treatment of chronic anal fissure. Methods All patients with symptomatic chronic anal fissure were randomly assigned to pneumatic balloon dilatation or lateral internal sphincterotomy and invited to complete a standardized questionnaire inquiring about their symptoms. Anal ultrasonography and anal manometry were performed before and six months after surgery. A proctologic examination was performed between the fifth and sixth postoperative weeks. Anal continence, scored by using a validated continence grading scale, was evaluated preoperatively at 1 and 6 weeks and at 12 and 24 months. Results Fifty-three patients, who satisfied selection criteria, were enrolled in the trial. Four patients (7.5 percent) were lost to follow-up. Twenty-four patients (11 males; mean age, 42 ± 8.2 years) underwent pneumatic balloon dilatation and 25 patients (10 males; mean age, 44 ± 7.3 years) underwent lateral internal sphincterotomy. Fissure-healing rates were 83.3 percent in the pneumatic balloon dilatation and 92 percent in the lateral internal sphincterotomy group. Recurrent anal fissure was observed in one patient (4 percent) after lateral internal sphincterotomy. At anal manometry, mean resting pressure decrements obtained after pneumatic balloon dilatation and lateral internal sphincterotomy were 30.5 and 34.3 percent, respectively. After pneumatic balloon dilatation, anal ultrasonography did not show any significant sphincter damage. At 24-month follow-up, the incidence of incontinence, irrespective of severity, was 0 percent in the pneumatic balloon dilatation group and 16 percent in the lateral internal sphincterotomy group (P < 0.0001). Conclusions As lateral internal sphincterotomy, pneumatic balloon dilatation grants a high anal fissure-healing rate but with a statistically significant reduction in postoperative anal incontinence. Reprints are not available.     

Fatigue rate index as a new measurement of external sphincter function

PURPOSE: Assessment of sustained voluntary contraction of the external sphincter is helpful in evaluating the patient who has a defecation disorder on presentation. A new index of external sphincter function is described. METHOD: A prospective registry of patients referred for computerized anal manometry using standard protocols was reviewed. Patients were grouped by primary symptoms; those with overlapping complaints were excluded. The rate of fatigue, defined as the change in stationary squeeze over a 40-second period of voluntary contraction, was calculated by linear regression analysis. Fatigue rate index, a calculated measure of time necessary for the external sphincter to become completely fatigued, was determined to permit comparison of external sphincter fatigue in patients with different complaints. RESULTS: Twenty-six healthy volunteers (15 women; mean age, 45 years), 33 patients with a primary complaint of anal seepage (13 women; mean age, 53 years), 75 patients with gross incontinence (61 women; mean age, 53 years), and 49 patients with severe constipation (41 women; mean age, 45 years) were evaluated. Mean resting and squeeze pressures were 55 mmHg and 107 mmHg for volunteers, 37 mmHg and 97 mmHg for patients with seepage, 30 mmHg and 49 mmHg for incontinent patients, and 56 mmHg and 93 mmHg for constipated patients. Pudendal neuropathy, as evidenced by a prolonged pudendal nerve terminal motor latency (>2.4 ms), was identified in 13 percent of volunteers, 32 percent of patients with seepage, 54 percent of incontinent patients, and 38 percent of constipated patients. Mean fatigue rate index was 3.3 minutes for volunteers, 2.3 minutes for seepage patients, 1.5 minutes for incontinent patients, and 2.8 minutes for constipated patients. Compared with volunteers and patients with seepage, the incontinent patients had a significantly shorter fatigue rate index (P<0.05; Student'st-test), which was independent of the variations in resting pressure (P<0.05; two-way analysis of variance). CONCLUSION: The external anal sphincter is normally subject to fatigue. Patients with worsening degrees of incontinence have a predictably lower fatigue rate index. Fatigue rate index is a simple measure of external sphincter integrity, which may be used in assessment of sphincter function and future treatment protocols.Winner of the Northwest Society of Colon and Rectal Surgeons Award.Read, in part, at the meeting of The American Society of Colon and Rectal Surgeons, Philadelphia, Pennsylvania, June 22 to 26, 1997     

Effect of delivery on anal sphincter morphology and function

PURPOSE: Anal sphincter injury is a serious complication of childbirth, which may result in persistent anal incontinence. Occult injuries, visualized with endoanal ultrasonography, have previously been reported in up to 35 percent of females in a British study. The aim of the present study was to study anal sphincter morphology and function before and after delivery in primiparous females in the United States. METHODS: Thirty-eight primiparous patients (mean age, 31 years) were evaluated with endoanal ultrasonography, anal manometry, and pudendal nerve terminal motor latency during pregnancy and after delivery. Bowel function before and after delivery was recorded according to set questionnaires. Cesarean section was performed in three patients. RESULTS: Clinical sphincter tears, requiring primary repair, occurred in 15 percent of the patients. After delivery endoanal ultrasonography revealed disruptions in the external anal sphincter in six patients, but no patient had disruption in the internal anal sphincter. One patient had slight scarring in the external sphincter. Of the seven patients with pathologic findings at endoanal ultrasonography, the left pudendal latency increased after delivery (P<0.05), and manometric results were reduced. Three of these seven patients had a third-degree or fourth-degree tear during delivery. All investigations were normal in the three patients who underwent cesarean section. CONCLUSIONS: The present study demonstrates a significant frequency of sphincter injuries (20 percent) after vaginal delivery. Obstetricians should be aware of this risk and explicitly inquire about incontinence symptoms at follow-up after delivery.Health East Foundation and Mead Johnson Pharmaceutical Inc. provided economic support, enabling participating volunteers to receive a stipend and baby supplies on completion of their tests.Dr. Mellgren was supported by grants from Health East Foundation and Karolinska Institutet Research Funds. Dr. Zetterström was supported by grants from Karolinska Institutet Research Funds.Read at the meeting of The American Society of Colon and Rectal Surgeons, San Antonio, Texas, May 2 to 7, 1998. Poster presentation at the XVIIth Biennial Congress of the International Society Of University Colon and Rectal Surgeons, Malmö, Sweden, June 7 to 11, 1998.     

The relationship of pudendal nerve terminal motor latency to squeeze pressure in patients with idiopathic fecal incontinence

PURPOSE: With the advent of transanal ultrasonography it has been possible to identify those incontinent patients without sphincter defects. The majority of these patients are now thought to have neurogenic fecal incontinence secondary to pudendal neuropathy. They have been found to have reduced anal sphincter pressures and increased pudendal nerve terminal motor latencies. The aim of this study was to determine whether in those incontinent patients who do not have a sphincter defect, prolonged pudendal nerve terminal motor latency correlates with anal manometry, in particular maximum squeeze pressure. METHODS: Sixty-six incontinent patients were studied with transanal ultrasonography, anorectal manometry, and pudendal nerve terminal motor latency. Twenty-seven continent controls had anorectal manometry and pudendal nerve terminal motor latency measured. RESULTS: Maximum resting pressure and maximum squeeze pressure were significantly lower in the group of incontinent patients with bilateral prolonged pudendal nerve terminal motor latency (median maximum resting pressure = 26.5 mmHg; median maximum squeeze pressure = 60 mmHg) when compared with incontinent patients with normal bilateral pudendal nerve terminal motor latencies (median maximum resting pressure = 46 mmHg; median maximum squeeze pressure = 79 mmHg; maximum resting pressure P = 0.004; and maximum squeeze pressure P = 0.04). In incontinent patients with no sphincter defects no correlation between pudendal nerve terminal motor latency and maximum squeeze pressure was found (r = -0.109, P = 0.48) and maximum squeeze pressure did not correlate with bilateral or unilateral prolonged pudendal nerve terminal motor latency (r = -0.148, P = 0.56 and r = 0.355, P = 0.19 respectively). CONCLUSIONS: In patients with idiopathic fecal incontinence damage to the pelvic floor is more complex than damage to the pudendal nerve alone. Although increased pudendal nerve terminal motor latency may indicate that neuropathy is present, in patients with neuropathic fecal incontinence, pudendal nerve terminal motor latency does not correlate with maximum squeeze pressure. Normal pudendal nerve terminal motor latency does not exclude weakness of the pelvic floor.     

The clinical contribution of integrated laboratory and ambulatory anorectal physiology assessment in faecal incontinence

To determine the clinical value of anorectal physiology testing, we have assessed 73 patients with neurogenic incontinence (median age 55 years, 60 female) and 115 controls (median age 48 years, 81 female). All the faecally incontinent patients displayed abnormal anal mucosal electrosensitivity and prolonged pudendal nerve latencies. Rectal compliance was poor in 14% of patients with neurogenic incontinence. Twenty-seven sphincter injuries were identified by endoanal ultrasonography in patients with neurogenic incontinence. Anal sphincter electromyographic abnormalities were demonstrated in all the incontinent patients. Anal pressures were lower in the incontinent group. Frequent, abnormal internal sphincter relaxations were observed in patients with incontinence during ambulatory assessment. These tests provide objective evidence of injury but do not frequently affect clinical decision making. Endoanal ultrasonography and ambulatory assessment provided clinical information of the mechanism of incontinence in 60% of patients.

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Résumé Pour déterminer la valeur clinique des tests physiologiques ano-rectaux nous avons étudié 73 patients avec une incontinence neurogénique (âge moyen 55 ans, 60 femmes) et 115 contrôles (âge moyen 48 ans, 81 femmes). Tous les malades incontinent fécaux montraient une électrosensibilité de la muqueuse anale anormale et une latence prolongée du nerf honteux interne. La compliance rectale était faible chez 14% des patients avec incontinence neurogénique. 27 traumatismes sphinctériens fûrent identifiés par échographie endorectale chez des patients avec une incontinence neurogénique. Des anomalies électromyographiques du sphincter anal ont été démontrées chez tous les malades incontinents. Les pressions anales étaient plus basses dans le groupe incontinent. Des phénomènes d'ouverture anormale du sphincter interne étaient fréquemment observés chez les patients incontinents durant l'étude ambulatoire. Ces tests montrent objectivement la présence d'un traumatisme mais n'influent pas souvent l'aspect décisionnel clinique. L'échographie endo-rectale et la manométrie ambulatoire fournissent des informations cliniques sur le mécanisme de l'incontinence dans 60% des cas.

     

Endosonographic assessment of the anal sphincter after surgical reconstruction

PURPOSE: Patients with anal incontinence attributable to trauma are usually treated by sphincter reconstruction. Failures because of incomplete reconstruction may possibly be detected by anal endosonography which gives detailed information on the anal sphincter muscles. The aim of this study was to describe the endosonographic findings in patients after sphincter reconstruction. MATERIALS AND METHODS: Ten female patients who had undergone surgical sphincter reconstruction using an overlapping technique because of anal incontinence were studied with anal endosonography a median of six months after surgery. Five patients were fully continent, three were incontinent for flatus, and two patients were still incontinent for solid stool at the time of this study. Eight patients had also been studied with endosonography before surgery, and, in these patients, we compared the initial sonograms with the follow-up sonograms. The angular extent of the endosonographic defects in the external sphincter before and after reconstruction was measured in degrees and compared with the outcome of surgery. RESULTS: After reconstruction, continuity of the external anal sphincter was completely restored at all levels in four patients, one of whom still had anal incontinence. Continuity was partially restored in three patients: two were fully continent, while one patient, previously incontinent for stool, was incontinent for flatus. In three patients the continuity was restored at one level but a persisting defect was found at a different level. In two of these patients the grade of incontinence was unchanged. Three patients also had defects in the internal anal sphincter. CONCLUSION: After surgical sphincter reconstruction for anal incontinence, we found sphincteric defects in six patients, including four of five patients who still had some degree of incontinence. Thus, endosonography may be used for postoperative assessment and may explain the unsatisfactory results of surgery in some patients. We recommend that endosonography be also performed preoperatively, whereby the effect of the operation on the size of the sphincteric defect can be assessed.     

Recovery of the internal anal sphincter following rectopexy: A possible explanation for continence improvement

Twenty-one patients suffering from rectal prolapse (n=15) or internal rectal procidentia (n=6) were investigated clinically and by anorectal manometry prior to and six months following rectopexy. Rectal prolapse was associated with incontinence in 67% (10/15) of the patients preoperatively. The moderately or severely incontinent patients had lower than normal maximum anal resting pressures (MAP) and those with severe incontinence also had lower than normal maximum squeeze pressure (MSP). Postoperatively only 20% (3/15) of the patients remained incontinent and none of them suffered severe incontinence. MAP values increased significantly indicating that improvement of the function of the internal anal sphincter may be one of the factors contributing to better continence. Rectal sensibility was impaired in patients with rectal prolapse as compared to 15 controls. There was no postoperative change. Patients with internal rectal procidentia had normal MAP and MSP and no postoperative change could be demonstrated.     

Anorectal functioning in fecal incontinence

Manometric testing was performed on three groups of subjects: 14 patients complaining of fecal incontinence, 14 age- and sex-matched continent patients, and 14 sex-matched younger normal controls. The younger group displayed significantly stronger contractions of the external anal sphincter and puborectalis than the two patient groups, which did not differ. No differences were found in the relaxation of the internal anal sphincter. The incontinent group required a significantly larger stimulus in order to detect rectal distension compared to either the continent patients or the younger normals. An additional group of unmatched normals and incontinent patients demonstrated significant differences in their ability to retain rectally infused saline. The patients leaked sooner and retained less;however, the performance of the normals was considerably reduced from that reported in previous studies. The aging process seems to result in weakening of the striated muscles of the anal canal, although fecal incontinence need not occur. The afferent limb of the anorectal sensorimotor mechanism does not necessarily deteriorate with aging. A lower threshold for sensation of rectal distension among continent individuals apparently helps them to avoid incontinent episodes, even though maximum contractile pressures in their anal canal are no different from a comparable group of incontinent individuals.