Sacral Nerve Stimulation for Fecal Incontinence Related to Obstetric Anal Sphincter Damage

Purpose Sphincter repair is the standard treatment for fecal incontinence secondary to obstetric external anal sphincter damage; however, the results of this treatment deteriorate over time. Sacral nerve stimulation has become an established therapy for fecal incontinence in patients with intact sphincter muscles. This study investigated its efficacy as a treatment for patients with obstetric-related incontinence. Methods Fecally incontinent patients with external sphincter defects who would normally have undergone overlapping sphincter repair as a primary or repeat procedure were included. Eight consecutive women (median age, 46 (range, 35–67) years) completed temporary screening; all eventually had permanent implantation. Results Six of eight patients had improved continence at median follow-up of 26.5 (range, 6–40) months. Fecal incontinent episodes improved from 5.5 (range, 4.5–18) to 1.5 (range, 0–5.5) episodes per week (P = 0.0078). Urgency improved in five patients, with ability to defer defecation improving from a median of <1 (range, 0–5) minute to 1 to 5 (range, 1 to >15) minutes (P = 0.031, all 8 patients). There was no change in anal manometry or rectal sensation. There was significant improvement in lifestyle, coping/behavior, depression/self-perception, and embarrassment as measured by the American Society of Colon and Rectal Surgery fecal incontinence quality of life score. Conclusions Sacral nerve stimulation is potentially a safe and effective minimally invasive treatment for fecal incontinence in patients with de novo external anal sphincter defects or defects after unsuccessful previous external anal sphincter repair, although numbers remain small. Dr. Michael Kamm is a consultant to and received research support from Medtronic, however, study design, performance, analysis, and reporting have been conducted without the influence of Medtronic.     

Sacral Nerve Stimulation is more Effective than Optimal Medical Therapy for Severe Fecal Incontinence: A Randomized,Controlled Study

Purpose This randomized study was designed to compare the effect of sacral neuromodulation with optimal medical therapy in patients with severe fecal incontinence. Methods Patients (aged 39–86 years) with severe fecal incontinence were randomized to have sacral nerve stimulation (SNS group; n = 60) or best supportive therapy (control; n = 60), which consisted of pelvic floor exercises, bulking agent, and dietary manipulation. Full assessment included endoanal ultrasound, anorectal physiology, two-week bowel diary, and fecal incontinence quality of life index. The follow-up duration was 12 months. Results The sacral nerve stimulation group was similar to the control group with regard to gender (F:M = 11:1 vs. 14:1) and age (mean, 63.9 vs. 63 years). The incidence of a defect of ≤ 120° of the external anal sphincter and pudendal neuropathy was similar between the groups. Trial screening improved incontinent episodes by more than 50 percent in 54 patients (90 percent). Full-stage sacral nerve stimulation was performed in 53 of these 54 “successful” patients. There were no septic complications. With sacral nerve stimulation, mean incontinent episodes per week decreased from 9.5 to 3.1 (P < 0.0001) and mean incontinent days per week from 3.3 to 1 (P < 0.0001). Perfect continence was accomplished in 25 patients (47.2 percent). In the sacral nerve stimulation group, there was a significant (P < 0.0001) improvement in fecal incontinence quality of life index in all four domains. By contrast, there was no significant improvement in fecal continence and the fecal incontinence quality of life scores in the control group. Conclusions Sacral neuromodulation significantly improved the outcome in patients with severe fecal incontinence compared with the control group undergoing optimal medical therapy. *Deceased. Read at the meeting of The American Society of Colon and Rectal Surgeons, St. Louis, Missouri, June 2 to 6, 2007.     

Experimental Models of Neuropathic Fecal Incontinence: An Animal Model of Childbirth Injury to the Pudendal Nerve and External Anal Sphincter

Purpose  Childbirth is the most common cause of fecal incontinence and damage to the pudendal nerve is a major component of childbirth injury. This study was designed to develop an acute animal model of injury to the innervation of the external anal sphincter. Methods  Forty-eight female virgin wistar rats were studied. Two models of neuropathic injury were developed. Bilateral inferior rectal nerve crush (Group A) acted as a positive control. Prolonged intrapelvic retrouterine balloon inflation (Group B) simulated the pelvic compressive forces of labor. Quantitative analysis of external anal sphincter muscle function was performed by using electromyography, external anal sphincter specific force production, and stereologic calculation of external anal sphincter mass. Results  Injury in both groups caused significant atrophy of the external anal sphincter (P = 0.002, ANOVA) and electromyographic evidence of reinnervation at one week. Specific force (mN force per mg mass) was not altered. External anal sphincter muscle mass recovered after four weeks in Group B. Conclusions  Balloon dilation within the boney pelvis results in denervation of the external anal sphincter and offers an experimental model of the effects of childbirth on the continence mechanism in humans. Supported by a grant from The Health Research Board, Ireland. Presented at the meeting of The American Society of Colon and Rectal Surgeons, St. Louis, Missouri, June 2 to 6, 2007, and was the winner of the Research Forum Prize.     

Sacral Nerve Stimulation Can Be Successful in Patients With Ultrasound Evidence of External Anal Sphincter Disruption

PURPOSE This study was designed to determine whether patients with fecal incontinence and endoanal ultrasound evidence of anal sphincter disruption may be successfully treated by sacral nerve stimulation.METHODS Five consecutive females with incontinence to solids and endoanal ultrasound evidence of anal sphincter disruption were treated by a two-week trial of sacral nerve stimulation. If successful, patients then proceeded to permanent sacral nerve stimulation implantation.RESULTS Five patients, aged 34 to 56 years, were treated by temporary sacral nerve stimulation. Four had symptoms starting after childbirth. Two had previously had an anterior sphincter repair. After a two-week trial, three females reported full continence and an improvement in all aspects of their Rockwood fecal incontinence quality of life scores. These three females underwent permanent sacral nerve stimulation implantation. The remaining two patients reported no improvement and underwent dynamic graciloplasty or end colostomy respectively.CONCLUSIONS Sacral nerve stimulation may successfully restore bowel continence in some patients with endoanal ultrasound evidence of a defect in their external anal sphincter.     

Anal Resting Pressures at Manometry Correlate with the Fecal Incontinence Severity Index and with Presence of Sphincter Defects on Ultrasound

Introduction  We describe the relationship between anorectal manometry, fecal incontinence severity, and findings at endoanal ultrasound. Methods  A total of 351 women completed the Fecal Incontinence Severity Index, underwent anorectal manometry, and endoanal ultrasound. Severity index and manometry pressures in 203 women with intact sphincters on ultrasound were compared with pressures in 148 women with sphincter defects. Relationships between resting and squeeze pressures, severity index, and size of sphincter defects were evaluated. Results  Mean severity index in patients with and without sphincter defect was 35.7 vs. 36.7 (not significant). Worsening index correlated with worsening mean and maximum resting pressure (P < 0.0001). Differences were observed in mean and maximum resting pressure between the patients with and without sphincter defects (26.6 vs. 37.2, P < 0.0001; 39.4 vs. 51.7, P < 0.001). Resting pressures correlated with the sizes of defect (P < 0.0001). Conclusions  Patients with and without sphincter defects had similar severity scores, but patients with defects had a significant decrease in resting pressures. Patients with larger sphincter defects had lower severity scores and resting pressures. Until a manometry cutoff can be set to discriminate between absence and presence of defects, both manometry and ultrasound should be offered to patients with history of anal trauma. Read at the meeting of The American Society of Colon and Rectal Surgeons, St. Louis, Missouri, June 2 to 6, 2007. Reprints are not available.     

Anal endosonography: Relationship with anal manometry and neurophysiologic tests

Thirty-seven patients were referred for evaluation of anal function; their clinical diagnoses were traumatic fecal incontinence (13), idiopathic (pudendal neuropathy) fecal incontinence (7), fecal soiling (9), and other (8). In all patients, anal endosonography (sphincter defects and internal sphincter thickness [IST]) and anal manometry (maximal basal pressure [MBP] and maximal squeeze pressure [MSP]) were performed. In 18 patients, neurophysiologic tests (EMG-maximal contraction pattern [MCP], single-fiber EMG [fiber density; FD], and pudendal nerve terminal motor latency [PNTML]) were also performed. Endosonography demonstrated in seven patients both an internal and external sphincter defect (Group 1), in seven patients an internal sphincter defect and in one patient an external sphincter defect (Group 2), and in 22 patients no sphincter defect (Group 3). There was a significant difference among these three groups for MBP and MCP, the lowest being in Group 1. Between the patients with traumatic fecal incontinence and idiopathic fecal incontinence, no differences in IST, MBP, MSP, MCP, FD, and PNTML were found. In two patients with a suspected obstetric trauma, there was an unexpected additional severe pudendal neuropathy. In one patient with a suspected obstetric trauma, no damage of the anal sphincters could be demonstrated. In one patient with suspected idiopathic fecal incontinence, there was an additional, unsuspected defect of the internal sphincter. There was concordance between endosonography and EMG in the mapping of the external sphincter. Clinical diagnoses can be misleading in differentiating between traumatic and idiopathic fecal incontinence; anal endosonography provides unsuspected and additional information about the sphincters; PNTML can reveal unsuspected neuropathy in traumatic fecal incontinence. Therefore, the combination of endosonography and PNTML is promising in selecting patients for surgery.     

Effect of Second Vaginal Delivery on Anal Function in Patients at Risk of Occult Anal Sphincter Injury after First Forceps Delivery

Purpose  The study was designed to determine the effect of further vaginal delivery on anal sphincter function in women after apparently uncomplicated primiparous forceps delivery. Methods  Fifty-two secundigravid women whose first child was forceps-assisted were compared with a control group of 20 women who had undergone spontaneous first vaginal delivery. Both groups were studied antenatally and again at 12 weeks after second delivery using a standardized bowel function questionnaire, endoanal ultrasound, and anal manometry. The primary outcome was fecal incontinence score after second delivery. Results  Before second delivery, 20 of 52 (39 percent) of the forceps group and 3 of 20 (15 percent) control subjects (P = 0.103) reported minor alteration in fecal incontinence. Endoanal ultrasound was more frequently abnormal (38/52 (73 percent) vs. 6/20 (30 percent); P = 0.002), and median anal canal squeeze (71 vs. 104 mmHg; P = 0.004) and resting pressures (43 vs. 58 mmHg; P = 0.004) were lower in the forceps group. There was no difference in continence score between first and second delivery for the forceps group (P = 0.19) group or control subjects (P = 0.18). However, 10 of 38 (26 percent) women with an abnormal endoanal ultrasound after first forceps delivery developed new or worsening symptoms after second delivery. Conclusions  One-quarter of women with occult anal sphincter injury after first forceps delivery experienced some minor alteration in fecal continence after the second delivery. Presented at the 23^rd annual meeting of the Society for Maternal Fetal Medicine, San Francisco, California. Supported by the Irish Health Research Board.     

Pudendal neuropathy and severity of incontinence but not presence of an anal sphincter defect may determine the response to biofeedback therapy in fecal incontinence

PURPOSE: It has been suggested that the severity of fecal incontinence, the presence of pudendal neuropathy, or an external anal sphincter defect does not preclude clinical improvement with biofeedback therapy. A discrepancy, however, is frequently found between subjective improvement and objective results after biofeedback therapy. Our aim was to assess whether severity of fecal incontinence, presence of pudendal neuropathy, or an external anal sphincter defect could influence the results of manometric parameters after biofeedback therapy in patients with fecal incontinence. METHODS: Biofeedback therapy was used to treat 27 patients with fecal incontinence (25 women; mean age, 53; range, 29–74 years), according to a strict protocol. Manometry, pudendal nerve terminal motor latency, and anal ultrasound were performed in all patients before biofeedback therapy. Manometric evaluation of external anal sphincter function was performed after the biofeedback sessions. RESULTS: Eight of 27 patients had a good clinical response to biofeedback, but with no significant difference in their mean amplitude and duration of squeeze pressure before and after biofeedback. There was no relationship between the clinical results of biofeedback therapy and the initial severity of fecal incontinence, pudendal neuropathy, or external sphincter defect. Patients with severe incontinence (incontinence to solids) and pudendal neuropathy failed to improve the amplitude and duration of their maximum voluntary contraction after biofeedback therapy. Patients with mild fecal incontinence (incontinence to flatus, liquids, or both) (P<0.04), without pudendal neuropathy (P<0.02), or with (P<0.05) and without (P<0.05) external sphincter defect improved their external anal sphincter function after biofeedback therapy. CONCLUSION: In patients with fecal incontinence, the severity of symptoms and pudendal neuropathy should be considered as two factors of poor prognosis of favorable manometric results after biofeedback therapy. Improvement, on the other hand, may be expected after biofeedback therapy despite an external anal sphincter defect.Presented at the XXIst congress of the Societé Internationale Francophone d'Urodynamique, Lisbon, Portugal, May 14 to 16, 1998.     

Sacral nerve stimulation for treatment of fecal incontinence

PURPOSE: Many patients with fecal incontinence demonstrate a functional deficit of the internal anal sphincter or the external sphincter muscles without any apparent structural defects. Few patients are amenable to repair or substitution of the sphincter. However, sacral nerve stimulation appears to offer a valid treatment option for fecal incontinence. The objectives of this study were: to evaluate the efficacy of temporary stimulation of the sacral nerve roots (percutaneous nerve evaluation) in patients with functional fecal incontinence; to determine the mechanisms of possible improvement; and to evaluate if temporary stimulation could be reproduced and maintained by implanting a permanent neurostimulation system. METHODS: Twenty-three patients with fecal incontinence, 18 females and 5 males, median age of 54.9 years (range 28–71), underwent a percutaneous nerve evaluation test. Eleven patients (47.8 percent) also had urinary disorders: urge incontinence (4), stress incontinence (3), and retention (4). Associated disorders included perineal and rectal pain (1), spastic paraparesis (1), and syringomyelia (1). All patients underwent a preliminary evaluation using stationary anal manovolumetry, pudendal nerve terminal motor latency measurements, and anal ultrasound. A percutaneous electrode for the stimulation of the sacral nerve roots was positioned at the level of the third sacral foramen (S3) in 20 patients and S2 in 2 patients (1 patient missing). Stimulation parameters used were: pulse width 210µsec, frequency 25 Hz, and average amplitude of 2.8 V (range 1–6). The electrode was left in place for a minimum of 7 days. Five patients were successively implanted with a permanent sacral electrode with a stimulation frequency of 16 to 18 Hz and amplitude of 1.1–4.9 V. RESULTS: Seventeen of the 19 patients (89.4 percent) who completed the minimum percutaneous nerve evaluation period of 7 days (median 10.7 (range 7–30)), had a reduction of liquid or solid stool incontinence by more than 50 percent, and fourteen (73.6 percent) were completely continent for stool. The most important changes revealed by manovolumetry were an increase in resting pressure (P<0.001) and voluntary contraction (P=0.041), reduction of initial pressure for first sensation (P=0.049) and urge to defecate (P=0.002), and a reduction of the rectal volume for urge sensation (P=0.006). The percutaneous nerve evaluation results were reproduced at a median follow-up of 19.2 months (range 5 to 37) in the 5 patients who received a permanent implant. CONCLUSIONS: Temporary stimulation of the sacral roots (percutaneous nerve evaluation) can be of help in those patients with fecal incontinence, and the results are reproduced with permanent implantation. The positive effect on continence seems to be derived from not only the direct efferent stimulation on the pelvic floor and the striated sphincter muscle, but also from modulating afferent stimulation of the autonomous neural system, inhibition of the rectal detrusor, activation of the internal anal sphincter, and modulation of sacral reflexes that regulate rectal sensitivity and motility.     

Anal sphincter repair improves anorectal function and endosonographic image

PURPOSE: This study investigated the effect of anal sphincter repair on fecal continence in relation to anal endosonography and anal manometry. METHODS: Eighteen patients (7 male, 11 female) with anal sphincter defects and complaints of fecal incontinence (5), soiling (= liquid discharge; 3), or both (10) were studied before and after sphincter repair with endosonography and anal manometry. Complaints were the result of obstetric trauma (7), surgical trauma (7), both (3), and other trauma (1). Five patients had previous surgery. Preoperative endosonography showed a defect of both sphincters in nine patients, a defect of the external anal sphincter in five patients, and a defect of the internal anal sphincter in four patients. An overlapping sphincter repair was performed. RESULTS: Postoperatively and subjectively (S; patient's view), 13 (72 percent) patients became continent or improved; in 5 (28 percent) patients the complaints were unaltered. Objectively (O) (incontinence or soiling frequency), these figures were 12 (67 percent) and 6 (33 percent). Postoperative endosonographic images improved in 14 (78 percent) patients; defects of the sphincters (almost) disappeared (4) or were smaller (10). In the other four patients, images were unchanged. In two patients, overlapping of the muscle was clearly visible with anal endosonography. Clinical result (subjective (S) and objective (O)) of sphincter repair correlated with changes in anal endosonography (S,r=0.64,P <0.004; O,r=0.51,P=0.03) and anal manometry (S,r=0.54,P=0.038; O,r=0.44,P=0.09 (not significant)) and not with pudendal nerve latency. CONCLUSION: In 78 percent of our patients, endosonographic sphincter defect had diminished or disappeared after sphincter repair. There was a good correlation between clinical effect of sphincter repair and changes with anal endosonography and anal manometry. Postoperative persistent incontinence is attributable to remaining sphincter defects. Anal endosonography should be performed as a routine procedure in patients with fecal incontinence or soiling, also after failed surgery.Presented at the meeting of the American Gastroenterology Association, New Orleans, Louisiana, May 15 to 18, 1994.     

Overt Rectal Prolapse and Fecal Incontinence

PURPOSE  Rectal prolapse is frequently associated with fecal incontinence; however, the relationship is questionable. The study was designed to evaluate fecal incontinence in a large consecutive series of patients who suffered from rectal prolapse, focusing on both past history, anal physiology, and imaging. METHODS  Eighty-eight consecutive patients who suffered from an overt rectal prolapse (72 women, 16 men; mean age, 51.1 ± 19.5 years) as a main symptom were analyzed; 48 patients also experienced fecal incontinence compared with 40 without incontinence. Logistic regression analyses were performed. RESULTS  The two groups of patients did not differ with respect to parity, weekly stool frequency, main duration of symptoms before referral, occurrence of dyschezia, and digital help to defecate. Patients with prolapse who were older than 45 years (odds ratio (OR), 4.51 (1.49–13.62); P = 0.007) and those with a past history of hemorrhoidectomy (OR, 9.05 (1.68–48.8); P = 0.01) were significantly more incontinent. Incontinent group showed frequent internal anal sphincter defect compared with the continent group (60 vs. 6.2 percent; P = 0.0018). CONCLUSIONS  In patients with overt rectal prolapse, the occurrence of fecal incontinence needs special consideration for age and previous hemorrhoid surgery as causative factors. Anal weakness and sphincter defects are frequently observed.     

Injectable Silicone Biomaterial for Fecal Incontinence Caused by Internal Anal Sphincter Dysfunction Is Effective

PURPOSE Fecal incontinence caused by a weak or disrupted internal anal sphincter is common but there has been no effective treatment. This prospective study evaluates the medium-term clinical effects of an injectable silicone biomaterial, PTP^TM (Bioplastique), used to augment the internal anal sphincter.METHOD Eighty-two patients (64 females; median age, 66 years) with severe fecal incontinence and a low anal resting pressure caused by internal anal sphincter dysfunction (defect, n = 11; intact, n = 71) were randomized to PTP^TM injection into intersphincteric space and internal anal sphincter with (Group A, n = 42) or without (Group B, n = 40) guidance by endoanal ultrasound. Both groups were similar in terms of age, gender, past anorectal surgery, duration of follow-up (median, 6 months; range, 1–12 months), and baseline continence score. Sixty-two percent of Group A and 55 percent of Group B had prolonged pudendal nerve terminal motor latency.RESULTS There was no significant complication. Two patients in Group A and four patients in Group B noted minor discomfort at injection sites. At one month postprocedure, endoanal ultrasound confirmed retention of silicone biomaterial without migration. In both groups, fecal continence was significantly improved by PTP^TM implants 1 month after injection, but continued to improve significantly for up to 12 months in Group A and 6 months in Group B (P < 0.001). Improvement in fecal continence and maximum anal resting pressure was significantly greater in Group A, in whom injection was guided by endoanal ultrasound, than in Group B. At three months after injection, significantly more Group A patients than Group B patients achieved >50 percent improvement in Wexners continence score (69 percent vs. 40 percent; P = 0.014). Ninety-three percent of Group A and 92 percent of Group B had >50 percent improvement in global quality of life scores (visual analog scale). At a median follow-up of 6 months, all domains of the fecal incontinence quality of life scale improved significantly in both groups; however, the physical function and mental health scores of Short Form-12 only improved in Group A. A prolonged pudendal nerve terminal motor latency had no effect on functional outcome in either group.CONCLUSION Injection of silicone biomaterial provided a marked improvement in fecal continence and quality of life in patients with internal sphincter dysfunction, despite the presence of pudendal neuropathy.Read at the meeting of The American Society of Colon and Rectal Surgeons, Dallas, Texas, May 8 to 13, 2004.     

Evaluation of the sacroanal motor pathway by magnetic and electric stimulation in patients with fecal incontinence

PURPOSE: The aim of this controlled study was to examine whether it was feasible to use magnetic stimulation as a new diagnostic tool to evaluate the motor function of the sacral roots and the pudendal nerves in patients with fecal incontinence. PATIENTS AND METHODS: Nineteen consecutive patients (17 females) with a median age of 67 (range, 36–78) years referred for fecal incontinence and 14 healthy volunteers (six females) with a median age of 42 (range, 23–69) years were examined. Latency times of the motor response of the external anal sphincter were measured after electric transrectal stimulation of the pudendal nerve and magnetic stimulation of the sacral roots. RESULTS: The success rates of pudendal nerve terminal motor latency and sacral root terminal motor latency measurements were 100 and 85 percent, respectively, in the control group and 94 and 81 percent, respectively, in the fecal incontinence group. Median left pudendal nerve terminal motor latency was 1.88 (range, 1.4–2.9) milliseconds in the control group and 2.3 (range, 1.8–4) milliseconds in the fecal incontinence group (P<0.006). Median right pudendal nerve terminal motor latency was 1.7 (range, 1.3–3.4) milliseconds in the control group and 2.5 (range, 1.7–6) milliseconds in the fecal incontinence group (P<0.003). Median left sacral root terminal motor latency was 3.3 (range, 2.1–6) milliseconds in the control group and 3.7 (range, 2.8–4.8) milliseconds in the fecal incontinence group (P<3 0.03). Median right sacral root terminal motor latency was 3 (range, 2.6–5.8) milliseconds in the control group and 3.9 (range, 2.5–7.2) milliseconds in the fecal incontinence group (P=0.15). CONCLUSIONS: Combined pudendal nerve terminal motor latency and sacral root terminal motor latency measurements may allow us to study both proximal and distal pudendal nerve motor function in patients with fecal incontinence. Values of sacral root terminal motor latency have to be interpreted cautiously because of the uncertainty about the exact site of magnetic stimulation and the limited magnetic field strength.     

Overlap Technique Improves Results of Primary Surgery after Obstetric Anal Sphincter Tear

Purpose This study was designed to evaluate prospectively the results of the overlap technique in primary sphincter reconstruction after obstetric tear. Methods Obstetric tears in 44 women were operated on with primary overlap reconstruction. These women were investigated six to nine months after the operation. Results were compared with those of a historical control group of 52 women whose obstetric sphincter rupture had been treated with the end-to-end technique. Results The overlap group had significantly more incontinence symptoms after delivery and repair of the sphincter tear than before delivery (P < 0.0001); however, their incontinence symptoms were significantly fewer than those of the end-to-end group (P = 0.004). The prevalence of persistent rupture of the external anal sphincter was significantly lower in the overlap group (6/44, 13.6 percent) than in the end-to-end group (39/52, 75 percent; P < 0.0001). Internal anal sphincter rupture occurred in 5 patients (11.4 percent) in the overlap group and in 40 patients (76.9 percent) in the end-to-end group (P < 0.0001). Conclusions The overlap technique should be adopted as the method of choice for primary sphincter repair after obstetric tear.     

Atrophy and Defects Detection of the External Anal Sphincter: Comparison Between Three-Dimensional Anal Endosonography and Endoanal Magnetic Resonance Imaging

Purpose Using endoanal magnetic resonance imaging, atrophy of the external anal sphincter can be established. This aspect has not been thoroughly investigated using three-dimensional anal endosonography. The purpose of this study was to compare prospectively three-dimensional anal endosonography to magnetic resonance imaging in the detection of atrophy and defects of the external anal sphincter in patients with fecal incontinence. In addition, we compared both techniques for anal sphincter thickness and length measurements. Materials and Methods Patients with fecal incontinence underwent three-dimensional anal endosonography and magnetic resonance imaging. Images of both endoluminal techniques were evaluated for atrophy and defects of the external anal sphincter. External anal sphincter atrophy scoring with three-dimensional anal endosonography depended on the distinction of the external anal sphincter and its reflectivity. External anal sphincter atrophy scoring with magnetic resonance imaging depended on the amount of muscle and the presence of fat replacement. Atrophy score was defined as none, moderate, and severe. A defect was defined at anal endosonography by a hypoechogenic zone and at magnetic resonance imaging as a discontinuity of the sphincteric ring and/or scar tissue. Differences between three-dimensional anal endosonography and magnetic resonance imaging for the detection of external anal sphincter atrophy and defects were calculated. In addition, we compared external anal sphincter thickness and length measurements in three-dimensional anal endosonography and magnetic resonance imaging. Results Eighteen patients were included (median age, 58 years; range, 27–80; 15 women). Three-dimensional anal endosonography and magnetic resonance imaging did not significantly differ for the detection of external anal sphincter atrophy (P = 0.25) and defects (P = 0.38). Three-dimensional anal endosonography demonstrated atrophy in 16 patients, magnetic resonance imaging detected atrophy in 13 patients. Three-dimensional anal endosonography agreed with magnetic resonance imaging in 15 of 18 patients for the detection of external anal sphincter atrophy. Using the grading system, 8 of the 18 patients scored the same grade. Three-dimensional anal endosonography detected seven external anal sphincter defects and magnetic resonance imaging detected ten. Three-dimensional anal endosonography and magnetic resonance imaging agreed on the detection of external anal sphincter defects in 13 of 18 patients. Comparison between three-dimensional anal endosonography and magnetic resonance imaging for sphincter thickness and length measurements showed no statistically significant concordance and had no correlation with external anal sphincter atrophy. Conclusion This is the first study that shows that three-dimensional anal endosonography can be used for detecting external anal sphincter atrophy. Both endoanal techniques are comparable in detecting atrophy and defects of the external anal sphincter, although there is a substantial difference in grading of external anal sphincter atrophy. Correlation between three-dimensional anal endosonography and magnetic resonance imaging for thickness and length measurements is poor. Inconsistency between the two methods needs to be evaluated further. Supported in part by grant No. 945-01-013 from the Netherlands Organization for Health Research and Development. Presented in part at the United European Gastroenterology Week, Prague, Czech Republic, September 25 to 29, 2004. Reprints are not available.     

Endosonographic Imaging of Anal Sphincter Injury

PURPOSE: This study was designed to test the hypothesis that the extent of anal sphincter muscle injury as graded at endosonography correlates with the degree of functional impairment. METHODS: Three hundred and thirty adults presenting for evaluation of fecal incontinence were recruited. Ultrasound was performed with a 7.5-MHz radial rotating axial endoprobe in the left lateral position. Anal sphincter muscle tears were graded on the basis of the degree of circumferential involvement (< or >25 percent) and by an assessment of the superoinferior longitudinal extent of an external anal sphincter tear. Muscles that demonstrated multiple tears, poor visualization, or fragmentation were classed as fragmented. Sphincter injuries were correlated with basal and squeeze pressures at manometry, pudendal nerve terminal latencies, and the severity of symptoms using the Parks-Browning clinical score. RESULTS: Patients with an intact external anal sphincter had a higher squeeze pressure (mean, 162.6 cm H(2)O) than those with a partial- (mean, 125.7 cm H(2)O) or full-length tear (mean, 124.9 cm H(2)O; P < 0.0001). There was no significant difference in squeeze pressure between those with partial- vs. full-length external anal sphincter tears nor between circumference tears < or >25 percent. Basal pressure was significantly lower in those with a full-length external anal sphincter tear (47.8 cm H(2)O) vs. an intact external anal sphincter (65.7 cm H(2)O; P < 0.001). The basal pressure in those with an intact internal anal sphincter was not significantly different from those with clearly defined internal anal sphincter tears, and the degree of circumferential involvement was also not important in this regard. However, those with a fragmented internal anal sphincter had a significantly lower basal pressure than other subgroups of internal anal sphincter injuries (P < 0.001). There was no association between external or internal anal sphincter status and the mean pudendal nerve terminal motor latency, suggesting the patient groups were neurologically similar. There was no significant association between external or internal anal sphincter status and the severity of reported symptoms. CONCLUSION: Correlations between the presence or absence of muscle tears and reduced manometric function have been identified. Further grading of tears was of less importance. No relationship between muscle injuries and the severity of clinical symptoms could be elicited.     

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.     

Age Effects on Internal Anal Sphincter Thickness and Diameter in Nulliparous Females

Purpose Age can affect the delicate physiologic balance of the internal anal sphincter diameters and pressure governed by Laplace’s law. This study compares the effect of aging on the internal anal sphincter thickness and diameter in younger and older nulliparous females without symptoms of fecal incontinence undisturbed by an endoanal probe. Methods Magnetic resonance images were selected from a large database of nulliparous females to form two groups: “younger” females, aged 30 years and younger (n = 32), and “older” females, aged 50 years and older (n = 32). All patients were scanned without endoanal coils to allow undistorted measurement of the internal anal sphincter diameters. Inner and outer diameters were measured from axial magnetic resonance images and used to calculate sphincter thickness and mean radius by two independent investigators blinded to patient age. Results The mean age in the younger group was 26 ± 2.8 years, whereas that of the older group was 61.8 ± 7.6 years. Older females had a 33 percent thicker internal anal sphincter (younger vs. older: 4.5 ± 0.7 vs. 5.9 ± 1 mm; P < 0.001), a 20 percent larger inner diameter (7.1 ± 1.3 vs. 8.5 ± 1.8 mm; P = 0.001), and a 27 percent larger outer diameter (16 ± 2.1 vs. 20.3 ± 3.3 mm; P < 0.001) than younger females. Neither sphincter thickness nor inner or outer diameter correlated with body mass index. Conclusions There is an increase in internal anal sphincter thickness, inner diameter, and outer diameter, which correlates with age in asymptomatic nulliparous females. Supported by the National Institutes of Health, ORWH & NICHD Sex & Gender Factors Affecting Women’s Health SCOR: P50, and NICHD R01 HD 044406: NICHD R01 DK 051405, R01 HD 038665; German Research Foundation (DFG, HU1502/1–1). Presented as a poster at the annual meeting of the American Urogynecologic Society, October 19 to 21, 2006, Palm Springs, Florida. Presented as an oral poster at the annual meeting of the International Urogynecological Association, September 6 to 9, 2006, Athens, Greece. Presented as an oral poster and oral presentation at the annual meeting of the German Association of Gynecology and Obstetrics, September 19 to 22, 2006, Berlin, Germany.     

Direct Repair <Emphasis Type="Italic">vs.</Emphasis> Overlapping Sphincter Repair

PURPOSE: The aim of this study was to compare the results of two surgical techniques (direct end-to-end vs. overlapping) of delayed repair of a localized anterior defect of external anal sphincter after an obstetric trauma. METHODS: During a five-year period, 23 patients were randomly assigned to direct end-to-end repair (n = 12) or overlapping sphincter repair (n = 11), using 2-0 PDS sutures. Two patients from each group had an internal anal sphincter defect that also was repaired. All patients had a normal pudendal nerve terminal motor latency preoperatively. Evaluations included endoanal ultrasound, anorectal manometry, and neurophysiologic evaluation. Continence was assessed by the Cleveland Clinic Continence Score (0–20; 0, perfect continence; 20, complete incontinence). RESULTS: The two groups were comparable with regard to age (median, 45 years), past history of sphincter repair (n = 2), and posterior vaginal repair. There was no major morbidity. The wound-healing rate was identical between the two groups. However, of the patients undergoing overlapping repair, two had fecal impaction, and one had a urinary retention. Median preoperative continence score was 17 in both the direct-repair group (score, 8–20) and the overlap group (score, 7–20). At a median follow-up of 18 months, the improvement in continence was similar between the two surgical groups, with a median continence score of 3, respectively. In both surgical groups there was a significant and similar improvement in maximum squeeze pressure and in the functional anal canal length postoperatively (P < 0.05), but the mean resting pressure was relatively unchanged. In the overlap group, one patient developed a unilaterally prolonged pudendal nerve terminal motor latency that was persistent 22 months after surgery, and two patients had impaired fecal evacuation postoperatively. CONCLUSIONS: This randomized, controlled study suggests that the outcome is similar whether direct end-to-end or overlapping repair of a sphincter defect is performed. Overlapping repair might be associated with more difficulties with fecal evacuation and a prolonged pudendal nerve terminal motor latency postoperatively.     

Unilateral Pudendal Neuropathy is Common in Patients with Fecal Incontinence

Purpose Pudendal neuropathy and fecal incontinence frequently coexist; however, the contribution of neuropathy is unknown. The pudendal nerve innervates the external anal sphincter muscle, anal canal skin, and coordinates reflex pathways. Lateral dominance or a dominantly innervating nerve and its subsequent damage may have major implications in the etiology and treatment of fecal incontinence. This study was designed to establish the prevalence of pudendal neuropathy, in particular a unilateral one, and to examine the impact on anorectal function. Methods A total of 923 patients (745 females; mean age, 52 (range, 17–92) years) with fecal incontinence were studied using endoanal ultrasonography, anorectal manometry, rectal sensation, and pudendal nerve terminal motor latencies. Results A total of 520 patients (56 percent) demonstrated a pudendal neuropathy, which was unilateral in 38 percent (351 patients; 169 right-sided, 182 left-sided). Neuropathy, whether it was bilateral (bilateral vs. normal; 56 (range, 7–154) cm H₂O) vs. 67 (range, 5–215) cm H₂O; P < 0.01) or unilateral (unilateral vs. normal; 61 (range, 0–271) cm H₂O vs. 67 (range, 5–215) cm H₂O; P = 0.04) was associated with reduced anal resting tone. This also was seen with respect to squeeze increments (bilateral vs. normal; 34 (range, 0–207) cm H₂O vs. 52 (range, 0–378) cm H₂O; P < 0.001, unilateral vs. normal; 41 (range, 0–214) cm H₂O vs. 52 (range, 0–378) cm H₂O; P < 0.01). In those with intact sphincters, unilateral neuropathy was associated with reduced squeeze increments (unilateral vs. normal; 60 (range, 10–286) cm H₂O vs. 69 (range, 7–323) cm H₂O; P = 0.01) but no significant reduction in resting pressures. There was no association between pudendal neuropathy and abnormal rectal sensitivity. Conclusions Unilateral pudendal neuropathy is a common abnormality in individuals with fecal incontinence and is significantly associated with both attenuated resting pressures and squeeze increments. Although there are limitations in the interpretation of pudendal nerve terminal motor latencies, this study demonstrates that further exploration of the concept of lateral dominance is needed. Supported by a grant from Dunhill Medical Trust/Royal College of Surgeons. Poster presentation at the meeting of The American Society of Colon and Rectal Surgeons, Seattle, Washington, June 3 to 7, 2006. Reprints are not available.