Anal sphincter electromyography after colectomy, mucosal rectectomy, and ileoanal anastomosis

Standardization of anal sphincter electromyography: normative data

OBJECTIVES

Electromyography (EMG) of the external anal sphincter (EAS) is important in the evaluation of conus/cauda lesions, the differential diagnosis of parkinsonism and anal incontinence. The aim of our study was to establish normative data in a sufficiently large group of healthy subjects, using a rigorously standardized examination technique.

METHODS

Sixty-four subjects (aged 19-83 years) without pelvic or neurological disorders were included. Motor unit potentials (MUPs)/interference pattern (IP) samples were obtained from the EAS using multi-MUP and turn/amplitude analyses, respectively. The effect of age, gender, parity, and constipation on MUP/IP parameters was studied. For MUP parameters the lower/upper limits for mean values, and 'outlier' limits, and for IP parameters normal 'clouds' were calculated.

RESULTS

From 112 muscles 15-30 MUPs were sampled. As no effect of evaluated factors on mean values could be demonstrated, common reference values were calculated. Lower/higher limits for mean values were: amplitude 148/661 microV, duration 3.2/7.8 ms, area 87/625 microVms, and number of phases 2. 3/3.7. 'Outlier' limits for individual MUPs were: amplitude 84/1315 microV, duration 1.6/13.8 ms, area 46/1222 microVms, number of phases 2/6. From 95 muscles 2706 IP samples were obtained.

CONCLUSIONS

The presented normative data should allow valid quantitative EMG of the EAS muscle in patients.

Physiology of ileal pouch-anal anastomosis. Current concepts

PURPOSE

Increasing experience with ileal pouch-anal anastomosis (IPAA) associated with increasing knowledge about anorectal physiology has lead to a large number of publications. The purpose of this review is to evaluate the current understanding of fecal continence as revealed by the evolution of the ileoanal procedure.

METHODS

Review of the literature covering the most important physiologic parameters involved in fecal continence was undertaken.

RESULTS

Rectoanal inhibitory reflex is probably absent after IPAA but is preserved when distal anorectal mucosa is spared. Anal resting pressure decreases but is less affected when the internal anal sphincter is less traumatized. Squeeze pressure is not importantly affected, and the importance of reservoir function as a determinant of stool frequency is emphasized. IPAA does not affect the coordination between pouch and anal canal motility in the majority of cases. Normal continence is preserved, even during the night, by preserving a gradient of pressure between the pouch and anal canal.

CONCLUSIONS

Physiologic concepts are well established, but controversies about the continence mechanism related to IPAA remain. The IPAA procedure has allowed discrimination of details about the function of multiple structures involved in fecal continence.

State of the defunctionalized sphincter in patients undergoing ileoanal pouch anastomosis

PURPOSE

Our aim was to determine manometric status and functional outcome of the ileoanal pouch procedure in a subset of patients with defunctionalized anal sphincters as a result of long-term fecal diversion.

METHODS

The anal manometric profiles of 12 patients defunctionalized for one year or more were compared with 26 patients with nondefunctionalized anal sphincters. Functional data were obtained from the Lahey Clinic Ileoanal Pouch Registry.

RESULTS

Preoperative manometric data revealed a mean resting pressure of 91.5 mmHg in the nondefunctionalized group vs. 68.7 mmHg in the defunctionalized group; mean squeezing pressure was 171.7 mmHg (nondefunctionalized group) vs. 102.3 mmHg (defunctionalized group); and squeezing pressure volume was 1,283,000 mmHg3 (nondefunctionalized group) vs. 585,000 mmHg3 (defunctionalized group). Functionally both groups had a mean of 6.1 bowel movements in a 24-hour period and could defer defecation for a mean of 2 hours. Leakage occurred in 22 percent of the defunctionalized group and 17 percent of the nondefunctionalized group (P = 0.35).

CONCLUSION

Despite physiologic perturbations, the long-term, defunctionalized anal sphincter can adequately support a restorative procedure without regard to timing of pouch creation.

Pudendal neuropathy in evacuatory disorders

PURPOSE

Aims of the present study were to assess frequency of pudendal neuropathy in patients with constipation and fecal incontinence, to determine its correlation with clinical variables, anal electromyographic assessment, and anal manometric pressures, and to determine usefulness of the pudendal nerve terminal motor latency assessment in evaluation of these evacuatory disorders.

METHODS

From 1988 to 1993, 395 patients (constipated, 172; incontinent, 223) underwent pudendal nerve terminal motor latency, electromyography, and anal manometry. Pudendal neuropathy was defined as a pudendal nerve terminal motor latency greater than 2.2 ms.

RESULTS

Patients were a mean age of 60.7 (range, 17-88) years. Overall incidence of pudendal neuropathy was 31.4 percent (constipated, 23.8 percent; incontinent, 37.2 percent; P < 0.05). Incidence of pudendal neuropathy dramatically increased after 70 years of age in both groups (22 percent vs. 44 percent; P < 0.05). Moreover, subjects with pudendal neuropathy were older than those without pudendal neuropathy (mean age, 67 vs. 57 years; P < 0.05). The presence of pudendal neuropathy was associated with decreased motor unit potentials recruitment in patients with incontinence (P < 0.01). Patients with and without pudendal neuropathy had a similar mean squeezing pressure in both groups.

CONCLUSION

Pudendal neuropathy is an age-related phenomenon. Although pudendal neuropathy is associated with abnormal anal electromyographic findings in patients with incontinence, no association with anal manometric pressures was found. Pudendal nerve terminal motor latency assessment is a useful tool in the evaluation of patients with fecal incontinence, but its role in the assessment of constipated patients remains unknown.

Update on the surgical management of ulcerative colitis and ulcerative proctitis: current controversies and problems

: The surgical management of ulcerative colitis has been revolutionized in recent years by the development of the ileal pouch-anal procedure. Although it is now the operation of choice for most patients, there remain several controversies. A variety of designs of ileal pouch are available each with advantages and disadvantages. The technique used to anastomose the pouch to the anal canal is also open to debate with some surgeons favoring distal mucosectomy with eradication of all disease and others choosing to perform a stapled anastomosis to achieve better functional results. The main concern for gastroenterologists, however, is the risk of development of pouchitis. The etiology, diagnosis, and treatment of this condition will also be discussed in this review as well as the more classical options for the surgical treatment of ulcerative colitis.

Prospectively evaluating anal sphincter function after ileal pouch-anal canal anastomosis

The decreased anal sphincter pressure that occurs after ileal pouch-anal canal anastomosis (IPAA) has usually been attributed to damage of the internal and sphincter. We hypothesized that the operation damages both the internal and the external anal sphincter. Resting pressure in the anal canal (a function of internal and external sphincters), anal squeeze pressure (a function of external sphincter only), and the rectal-anal inhibitory reflex (involving the internal sphincter) were measured manometrically in 10 patients with ulcerative colitis (4 women and 6 men; mean age, 33 years; range: 20 to 49 years). The patients were studied while awake before IPAA, under general anesthesia with striated muscle blockade just before incision, awake 2 months later before ileostomy takedown, and again under anesthesia with blockade just before takedown. The operation decreased maximum resting anal pressure while awake and during anesthesia with blockade. The decrease was detected in the proximal anal canal but not in the distal anal canal. In addition, the operation impaired anal squeeze pressure and abolished the rectal-anal inhibitory reflex. We conclude that IPAA damages both the internal and the external anal sphincter.

Anal sphincter-saving operations for chronic ulcerative colitis

Three anal sphincter-saving operations--ileorectostomy, ileal pouch-anal anastomosis, and ileal pouch-distal rectal anastomosis--are currently being used in the surgical treatment of chronic ulcerative colitis. All three operations remove the disease, or most of it, and yet they maintain transanal defecation, reasonable fecal continence, and a satisfactory quality of life. All three avoid permanent abdominal ileostomy. Ileorectostomy is the easiest to perform, but it leaves residual disease in the remaining rectum and proximal anal canal that may cause symptoms and that may predispose the patient to cancer. In contrast, ileal pouch-anal anastomosis, although a more technically demanding procedure, totally eradicates the colitis. Its main drawbacks--frequent stooling, nocturnal fecal spotting, and pouchitis--are usually satisfactorily treated with loperamide hydrochloride and metronidazole. Ileal pouch-distal rectal anastomosis is somewhat easier to perform than ileal pouch-anal anastomosis and may result in less nocturnal fecal spotting. Like ileorectostomy, however, the operation leaves residual disease in the distal rectum and proximal anal canal. Considering all of these factors, the ileal pouch-anal operation is preferred today for most patients who require surgery for chronic ulcerative colitis.

Neurophysiologic assessment of the anal sphincters

One hundred twenty consecutive patients with either fecal incontinence (60 patients), chronic constipation (41 patients), or idiopathic intractable pelvic pain (19 patients) were prospectively assessed. Patients underwent concentric needle electromyography (EMG), bilateral pudendal nerve terminal motor latency evaluation, anorectal manometry, and cinedefecography. The most common EMG finding in patients with fecal incontinence was decreased recruitment of motor units with squeezing and polyphasic motor unit potentials; these are consistent with an injury pattern. The most common EMG finding in the constipated patients was paradoxical puborectalis contraction. This latter abnormality was also a frequent finding in patients with rectal pain, as was prolongation of pudendal nerve latency. Paradoxical puborectalis contraction was diagnosed more frequently with EMG than with cinedefecography. Inter-examination correlation was best in the incontinent group between EMG and manometry. Cinedefecography had poor correlation with EMG in all patient groups but was valuable in the detection of additional pathology such as rectoanal intussusception and anterior rectocele. Electromyography including pudendal nerve terminal motor latency assessment is a valuable adjunct in the evaluation of disorders of evacuation. The information it yields is complementary to that offered by more routine physiologic examinations.

Failed ileoanal anastomosis: correlations between clinical function and anal canal neurophysiologic and histologic examinations

Ten patients with an ileoanal anastomosis had conversion to permanent ileostomy 13 (range, 6-29) months after the primary procedure. Causes for reoperation were incontinence in seven patients, unacceptable stool frequency without incontinence in two patients, and atypia in the mucosal remnant with perfect continence in one patient. Stool frequency, continence function, anal canal resting pressure, external anal sphincter (EAS) EMG/pressure relationship (in terms of slope, m), EAS fiber density (FD), and pressure in the distal ileum were registered, and the mucosa and the anal sphincter muscles were examined histologically. There were significant correlations between continence function and EAS changes in terms of both neurophysiologic tests (m and FD) and the histologic picture. The abnormalities in six incontinent patients were consistent with denervation of the EAS. The main reason for fecal leakage in one patient was the high amplitude of pressure waves in the distal ileum. Preservation of mucosal epithelium proximal to the dentate line per se did not seem essential to maintain continence.

Anal sphincter function after colectomy, mucosal proctectomy, and ileoanal anastomosis

Anal sphincter investigations were performed in 41 patients with straight ileoanal anastomosis and in 10 controls. In 20 patients (group I) the mucosal stripping had been performed from the abdominal side, leaving 1-2 cm of distal anal mucosa. In 21 patients (group II) the anal mucosa had been stripped from the perineal side as far as the dentate line. Continence was perfect in all patients in group I and poor in 6 of 17 patients in group II, when examined 12 months after the operation. Anal canal resting pressure was normal in group I. In group II the resting pressure was significantly decreased and correlated to continence function. The maximum anal canal squeeze pressure was the same in the two groups. The slope of the regression line between pressure rise and integrated electromyography proved to be a useful criterion of the external anal sphincter function and was significantly correlated to degree of incontinence. This variable was significantly smaller in group II patients than in group I and controls. Thus, function of the anal sphincters was normal after mucosal proctectomy performed from above with preservation of a mucosal brim. Dysfunction of the internal and external anal sphincter was found after perineal mucosal dissection and was correlated to continence function.

Mucosal proctectomy with straight ileoanal anastomosis. A comparison of two methods

Straight ileoanal anastomosis was performed in 59 patients. In 32 patients (group I) mucosal dissection was performed from above with preservation of a distal mucosal brim. In 27 patients (group II) the mucosectomy was performed to the dentate line--in 26 patients from the perineal side and in 1 patient from the abdominal side. Diverting loop ileostomy was used in group II but not in group I. The results in group II were in every respect inferior to those in group I, with significantly more intestinal obstruction and more conversions to permanent ileostomy because of poor functional results. The patients with ulcerative colitis (UC) in group II had higher stool frequency (10 (6-12) versus 7.3 (5-8) per 24 h; p = 0.01) and significantly less 'neorectal' capacity and distensibility than the UC patients in group I at 12 months after the operation. Anal continence was perfect in group I. In group II, 5 of 15 of the patients had significant incontinence problems 12 months postoperatively. The differences in results are ascribed to the differences in surgical technique between the two groups, and especially to the harmful effect of anal dilatation.

Stapling techniques for easy construction of an ileal J-pouch

A technique for the extended use of GIA and EEA or ILS staplers in the easy construction of an ileal J-pouch and mucosal proctectomy has been described herein. The technique for construction of the J-pouch involves the almost exclusive multiple use of a GIA stapling device. The described mucosal proctectomy techniques use the EEA stapler for good traction and visualization for everted electrocautery suction mucosal dissection. With the use of these techniques, the integrity of the patient's tissue is preserved, suture lines are stronger, and the operating time is greatly reduced.

[Physiologic aspects of postoperative continence following ileoanal anastomosis with and without intrapelvic reservoir]

Clinical and electro-manometric investigations were performed in six patients with ileoanal anastomoses. The results were compared with electromyographic and electrophysiological observations in the literature. It can be shown that decreasing motility, increasing compliance and a normalisation of the frequency of stools is possible after ileoanal as well as after ileo-pouch-anal anastomoses. Following both procedures high amplitude phase waves may persist in the distal and even in the proximal ileum. These waves can be stopped by voluntary contractions of the striated sphincter muscles if the patient becomes aware of them. During the night, however, uncontrolled defecations may occur. Un-isoperistaltic bowel segments will become isoperistaltic a few weeks or months after the operation. However, pouch-anal anastomoses show a better compliance and lower amplitude segmental or peristaltic waves than ileoanal anastomoses.

S-pouches vs. J-pouches. A comparison of functional outcomes

Subjects undergoing proctocolectomy with ileoanal anastomosis of either a J-shaped or an S-shaped ileal reservoir were studied with respect to functional status. Both subjective and objective measures were used. The S-pouch subjects appeared to have better early functional results, but no differences were found between groups evaluated at least one year from ileostomy closure. While virtually all subjects preferred restorative proctocolectomy to their previous loop ileostomy, there was a relatively high frequency of bowel-related symptoms, worries about bowel activity, and associated behavioral changes. The actual significance of these symptoms is difficult to determine at present. Further assessment of the quality of life in individuals with restorative proctocolectomy in comparison with subjects undergoing alternative surgical treatments is recommended.

Restorative proctocolectomy with ileal reservoir and ileoanal anastomosis: a clinico-physiological study

The results of nine patients undergoing restorative proctocolectomy with ileal reservoir are presented. Mean frequency of defaecation per 24 h is 5.8. The reservoir was removed in one patient. Continence was normal in six patients and two had minor soiling. Manometry was normal in all except one with minor soiling and electromyography showed no features of sphincter denervation.

Familial polyposis coli. Results of mucosal proctectomy with ileoanal anastomosis

The outcome of mucosal proctectomy with ileoanal anastomosis in patients with polyposis coli has not been well studied. A series of 25 patients with polyposis treated at the Mount Sinai Hospital over a period of ten years is reported. The mean age of the patients was 23 years. Early postoperative complications were present in seven patients and consisted of thrombophlebitis (three), pelvic sepsis (three), and retraction of the anastomosis (one). Intestinal obstruction requiring laparotomy occurred in another five patients. Twenty-three patients were followed for a mean of 47 months after closure of the ileostomy. Ninety-one percent are satisfied with the operative results. The mean number of bowel movements per 24 hours is 6.0. All patients are continent, but eight have occasional episodes of rectal seepage at night. Nearly 50 percent require some antidiarrheal medication. New adenomatous polyps have developed just above the dentate line in four patients. Patients with polyposis coli seem to have fewer serious complications requiring excision of the ileoanal anastomosis than patients with ulcerative colitis. They also should have lifelong surveillance of the entire gastrointestinal tract even after total colectomy with ileoanal anastomosis.

Surgery for ulcerative colitis

Ileal pouch-anal anastomosis is a relatively new surgical alternative to conventional ileostomy in patients with chronic ulcerative colitis. The rationale for the operation is that the disease is cured by the colectomy, proximal proctectomy, and distal endorectal mucosal resection, but enteric continence is maintained because the anal sphincters are preserved and the reservoir capacity is restored by incorporating an ileal pouch. This article describes the criteria for selecting appropriate patients, the surgical technique, the short- and long-term clinical results, and the physiologic consequences of the operation. The possible implications of this new procedure on the future management of patients with chronic ulcerative colitis are also presented.

Achieving enteric continence: principles and applications

Continence may be defined broadly as the ability to defer the passage of enteric content voluntarily to a socially acceptable time and place. In health, continence is provided by the anorectum; several factors interplay to achieve control. When the colon and rectum are removed because of intractable inflammatory bowel disease, a Brooke ileostomy that is incontinent of stool and gas is traditionally constructed, and control of the stoma is provided by an external appliance. Although the functional results after a Brooke ileostomy are good, we believe that restoration of continence would enhance the quality of life. The methods by which continence is restored surgically have undergone evolutionary changes based on an expanding knowledge of the principles of continence gained in the laboratory. In this report, we detail the current status of our understanding of anorectal continence mechanisms and of the principles of ileal continence, in order to examine how "ileo-anal" continence has been achieved in patients who require proctocolectomy.

Anal and neorectal function after ileal pouch-anal anastomosis

Bowel function varies markedly among patients with colectomy and ileal pouch-anal anastomosis. Little is known of the mechanisms controlling fecal continence and frequency of defecation after operation. The aim of this study was to determine which features of the anal sphincter and neorectum accounted for the variation in clinical outcome. Twenty patients were studied 4 to 35 months after operation and compared to 12 healthy volunteers. Despite several patients exhibiting impaired fecal continence, anal sphincteric length and pressures and ileal pouch capacity and distensibility were similar in patients and controls. Patients with poor results, however, had rapid filling of their ileal pouch, which resulted in early onset of high amplitude propulsive pressure waves in the pouch. As these waves became more frequent, defecation resulted. Patients with poor results also were not able to empty adequately their pouch. The poorer the completeness of evacuation, the more frequent the defecation (r = 0.62, p less than 0.01). The authors conclude that rapid pouch filling and impaired pouch evacuation can lead to increased stool frequency in patients after ileal pouch-anal anastomosis.

Anoneorectal evaluation after colectomy and endorectal ileoanal anastomosis in children and young adults

Recent improvements in the technique of colectomy, rectal mucosectomy, and endorectal ileoanal anastomosis allow a satisfactory result in most patients. However, the clinical outcome is not entirely satisfactory in about 5% to 10% of patients because of excessive stool frequency or episodic fecal incontinence or both. We evaluated anoneorectal function postoperatively to help explain the mechanisms of the difficulties. Six patients with imperfect functional results (group 1) and 6 with good functional results (group 2) after ileoanal anastomosis and closure of the loop ileostomy were compared with 12 healthy volunteers who had not had operation, through a series of tests designed to evaluate anal sphincter and neorectal function. All patients were instructed in balloon dilation of the neorectum to develop a reservoir while awaiting closure of the ileostomy. Anal sphincter manometric measurements of resting and squeeze pressures were obtained with a 4-channel probe attached to a noncompliant pneumohydraulic perfusion system. Incremental inflation of an intraluminal bag while pressures were simultaneously recorded allowed determinations of neorectal capacity and distensibility. The efficiency of neorectal evacuation was assessed by instilling a labeled synthetic viscous load into the distal bowel. Patients in group 1 had lower resting anal pressures (P less than 0.05), lower squeeze pressures (P less than 0.05), smaller neorectal capacities (P = 0.13), and less neorectal distensibility (P = 0.27) than patients in group 2. Furthermore, the values for patients in group 2 closely approximated those found in healthy volunteers.(ABSTRACT TRUNCATED AT 250 WORDS)