Long-term results of anorectal myectomy for chronic constipation

RESULTS OF POSTERIOR MYECTOMY FOR THE TREATMENT OF CHILDREN WITH CHRONIC CONSTIPATION

BACKGROUND AND OBJECTIVES

The aim of this study was to evaluate the result of posterior myectomy in children with chronic constipation who underwent to this surgery.

METHODS

Forty eight children with chronic constipation who did not respond to diet, laxative, or enema were included. Children with abnormal barium enema showing transitional zone were excluded. Children with documented metabolic disease diabetes, and hypothyroidism were also excluded. All patients underwent posterior myectomy. Children were followed during 1 year after surgery regarding frequency of fecal evacuation, fecal consistency, straining during defecation, and diameter of feces. Data was analyzed using SPSS version 13.0 (Chicago, IL, USA).

RESULTS

Of 48 cases that underwent surgery, 21 were male and 27 were female. Age range was 1.5 to 11 years old. Mean duration of constipation before surgery was 22.79±17.08 (range 6-48 months). Mean duration of medical treatment was 14.90±10.31 (range= 6-48 months). Fecal consistency, feces diameter, number of bowel movements and straining during defecation were compared before and after surgery. The results were statistically significant ( P <0.001). Of all cases, 52% continued treatment of constipation after surgery for 1 year. Ganglion cells were absent in 32 cases. Ganglion cells were present in seven children. Proximal ganglion cell was found in nine cases Treatment response was not different between cases according to status of ganglion cell in biopsy.

CONCLUSION

Fecal consistency, feces diameter, number of bowel movements, and straining for defecation were improved after posterior myectomy. Another study with more sample is required for better evaluation of treatment.

Should we care about the internal anal sphincter?

The internal anal sphincter is currently regarded as a significant contributor to continence function. Four physiological and morphological aspects of the internal anal sphincter are presented as part of the current evidence base for its preservation in anal surgery. 1) The incidence of continence disturbance following deliberate internal anal sphincterotomy is underestimated, although there is presently no prospective imaging or physiologic data supporting the selective use of sphincter-sparing surgical alternatives. 2) Given that the resting pressure is a measure of internal anal sphincter function, its physiologic representation (the rectoanal inhibitory reflex) shows inherent differences between incontinent and normal cohorts which suggest that internal anal sphincter properties act as a continence defense mechanism. 3) Anatomical differences in distal external anal sphincter overlap at the point of internal anal sphincter termination may preclude internal anal sphincter division in some patients where the distal anal canal will be unsupported following deliberate internal anal sphincterotomy. 4) internal anal sphincter-preservation techniques in fistula surgery may potentially safeguard postoperative function. Prospective, randomized trials using preoperative sphincter imaging and physiologic parameters of the rectoanal inhibitory reflex are required to shape surgical decision making in minor anorectal surgery in an effort to define whether alternatives to internal anal sphincter division lead to better functional outcomes.

Antegrade colonic enemas and intestinal diversion are highly effective in the management of children with intractable constipation

PURPOSE

Intractable constipation in children is an uncommon but debilitating condition. When medical therapy fails, surgery is warranted; but the optimal surgical approach has not been clearly defined. We reviewed our experience with operative management of intractable constipation to identify predictors of success and to compare outcomes after 3 surgical approaches: antegrade continence enema (ACE), enteral diversion, and primary resection.

METHODS

A retrospective review of pediatric patients undergoing ACE, diversion, or resection for intractable, idiopathic constipation from 1994 to 2007 was performed. Satisfactory outcome was defined as minimal fecal soiling and passage of stool at least every other day (ACE, resection) or functional enterostomy without abdominal distension (diversion).

RESULTS

Forty-four patients (range = 1-26 years, mean = 9 years) were included. Sixteen patients underwent ACE, 19 underwent primary diversion (5 ileostomy, 14 colostomy), and 9 had primary colonic resections. Satisfactory outcomes were achieved in 63%, 95%, and 22%, respectively. Of the 19 patients diverted, 14 had intestinal continuity reestablished at a mean of 27 months postdiversion, with all of these having a satisfactory outcome at an average follow-up of 56 months. Five patients underwent closure of the enterostomy without resection, whereas the remainder underwent resection of dysmotile colon based on preoperative colonic manometry studies. Of those undergoing ACE procedures, age younger than 12 years was a predictor of success, whereas preoperative colonic manometry was not predictive of outcome. Second manometry 1 year post-ACE showed improvement in all patients tested. On retrospective review, patient noncompliance contributed to ACE failure.

CONCLUSIONS

Antegrade continence enema and enteral diversion are very effective initial procedures in the management of intractable constipation. Greater than 90% of diverted patients have an excellent outcome after the eventual restoration of intestinal continuity. Colon resection should not be offered as initial therapy, as it is associated with nearly 80% failure rate and the frequent need for additional surgery.

Systematic review of surgical options for idiopathic megarectum and megacolon

OBJECTIVE

A subgroup of patients with intractable constipation has persistent dilatation of the bowel, which in the absence of an organic cause is termed idiopathic megabowel (IMB). The aim of this systematic review was to evaluate the published outcome data of surgical procedures for IMB in adults.

METHODS

Electronic searches of the MEDLINE (PubMed) database, Cochrane Library, EMBase, and Science Citation Index were performed. Only peer-reviewed articles of surgery for IMB published in the English language were evaluated. Studies of all surgical procedures were included, providing they were performed on 3 or more patients, and overall success rates were documented. Studies were critically appraised in terms of design and methodology, inclusion criteria, success, mortality and morbidity rates, and functional outcomes.

RESULTS

A total of 27 suitable studies were identified, all evidence was low quality obtained from case series, and there were no comparative studies. The studies involved small numbers of patients (median 12, range 3-50), without long-term follow-up (median 3 years, range 0.5-7). Inclusion of subjects, methods of data acquisition, and reporting of outcomes were extremely variable. Subtotal colectomy was successful in 71.1% (0%-100%) but was associated with significant morbidity related to bowel obstruction (14.5%, range 0%-29%). Segmental resection was successful in 48.4% (12.5%-100%), and recurrent symptoms were common (23.8%). Rectal procedures achieved a successful outcome in 71% to 87% of patients. Proctectomy, the Duhamel, and pull-through procedures were associated with significant mortality (3%-25%) and morbidity (6%-29%). Vertical reduction rectoplasty (VRR) offered promising short-term success (83%). Pelvic-floor procedures were associated with poor outcomes. A stoma provided a safe alternative but was only effective in 65% of cases.

CONCLUSIONS

Outcome data of surgery for IMB must be interpreted with extreme caution due to limitations of included studies. Recommendations based on firm evidence cannot be given, although colectomy appears to be the optimum procedure in patients with a nondilated rectum, restorative proctocolectomy the most suitable in those with dilatation of the colon and rectum, and VRR in those patients with dilatation confined to the rectum. Appropriately designed studies are required to make valid comparisons of the different procedures available.

Review article: the management of pelvic floor disorders

Anorectal disorders, such as faecal incontinence, defecation difficulty and conditions associated with anorectal pain, are commonly encountered in the practices of gastroenterologists, urogynaecologists and colorectal surgeons. The evaluation of these disorders has been very much improved by the development and wider availability of diagnostic tests, such as manometry, endo-anal ultrasound, static and dynamic pelvic magnetic resonance imaging and electromyography. After briefly reviewing the normal anatomy and physiology of the anorectum, the pathophysiology and diagnostic approaches to faecal incontinence, defecation disorders and functional anorectal pain are discussed. Until recently, the management of these disorders has been largely anecdotal. However, our therapeutic armamentarium has been expanded by pharmacological agents, such as nitrates, calcium channel blockers and botulinum toxin, as well as the development of novel techniques, such as sacral nerve stimulation. These and other pharmacological, behavioural and surgical approaches are reviewed with respect to the robustness of evidence to support their efficacy in patients with these disorders.

Colostomy for treatment of functional constipation in children: a preliminary report

OBJECTIVES

Surgery is indicated in very few children with intractable functional constipation. A number of operations have been described with unpredictable outcome and significant morbidity. The authors present a series of 10 children who underwent a Hartmann procedure with end colostomy formation.

METHOD

Preoperative management, in addition to maximum conservative measures, included psychologic referral, rectal biopsy, transit studies, and contrast enemas. A standard Hartmann procedure was performed with on-table rectal washout, formation of a proximal sigmoid colostomy, limited anterior resection of hypertrophic proximal rectosigmoid, and oversewing of the rectal stump.

RESULTS

The series includes 10 pediatric patients (4 female, 6 male), in whom constipation was first reported at a median age of 3 years (range, 2 months-7 years) and surgical referral was made at 8 years (range, 1-14 years). Surgery was performed at a median age of 9.5 years (range, 2-15 years), and the median postoperative stay was 5 days (range, 4-9 days). Complications occurred in four patients (transient mild rectal discharge in 2, stomal prolapse in 1, and an unrelated small bowel obstruction in 1 patient with an additional Mitrofanoff stoma). Median postoperative follow-up was 31 months (range, 9-56 months), and the children and parents were all completely satisfied with the stoma.

CONCLUSION

Colostomy formation is a potential surgical option for severe functional constipation with low associated morbidity and high patient satisfaction.

Identification of patients likely to benefit from biofeedback for outlet obstruction constipation

BACKGROUND

Biofeedback for outlet obstruction constipation has a varying success rate. The aim of this study was to identify which patients are likely to respond to biofeedback.

METHODS

Thirty patients with severe outlet obstruction constipation were treated by a specialist nurse using three or four sessions of visual and auditory feedback of anal sphincter pressures. All patients were assessed by evacuating proctography, whole-gut transit studies and anorectal physiology before treatment.

RESULTS

Two patients did not complete the course of biofeedback. Nine patients improved. Before treatment these patients had predominantly normal anorectal physiology and were all able to open the anorectal angle at evacuating proctography. Nineteen patients did not improve, of whom only three had no measured abnormality other than inability to empty the rectum. Ten of these patients had abnormal anorectal physiology which may have been due to previous vaginal delivery.

CONCLUSION

Biofeedback for outlet obstruction constipation is more likely to be successful in patients without evidence of severe pelvic floor damage.

Surgery for constipation: a review

PURPOSE

Constipation is related to intestinal motility disorders (colonic inertia (CI)), pelvic floor disturbances (pelvic outlet obstruction), or a combination of both problems. This review summarizes the physiologic and pathophysiologic changes in patients with intractable constipation and gives an overview of surgical treatment options.

RESULTS

Although subtotal colectomy with ileorectal anastomosis is the best surgery for CI, there are still approximately 10 percent of patients who will complain of pain and constipation. A completion proctectomy and an ileoanal pouch procedure may be a viable option in a highly select group of patients. In patients with megabowel, reported results are mixed. Subtotal colectomy, partial colectomy for megacolon, and the Duhamel procedure for megarectum have all been reported with variable results. In patients with an isolated distended sigmoid colon, sigmoid colectomy has achieved good results. Anorectal myectomy has not been proven to be successful in the long term. However, in patients with adult short segment Hirschsprung's disease, myectomy can be successful. Patients with pelvic outlet obstruction can be successfully treated with biofeedback. In a small group of patients with a rectocele or a third degree sigmoidocele, surgical intervention yields a high success rate. Division or resection of the puborectalis muscle is not recommended. In patients with a mixed pattern of CI and pelvic outlet obstruction, surgical intervention alone is often not successful. These patients achieve better results by conservative treatment of pelvic outlet obstruction, followed by a colectomy.

CONCLUSION

Surgical intervention for patients with intractable constipation is rarely necessary. However, thorough preoperative physiologic testing is mandatory for a successful outcome.

Anteriorly located anus: is constipation caused by abnormal location of the anus?

Anteriorly located anus (ALA) is frequently associated with severe constipation accompanied by defecation pain. Between 1988 and 1994, the authors treated 27 children (26 girls, 1 boy; age range, 0 to 11 years) to surgically correct ALA. The operation was performed according to a uniform protocol to longitudinally divide the internal sphincter muscle from the anal skin level to 2 cm above the dentate line on the posterior wall of the anorectum. For anal reconstruction, any of the conventional procedures was employed. Twenty-two of the 27 patients have had follow-up in our clinic for 12 months to 6 years (mean, 2.75 years). Eighteen are completely free of constipation and defecation pain and have regular spontaneous bowel movements. The other four require occasional use of enemas or laxatives. Anal incontinence did not occur in any patient. The results of this study suggest that abnormal function of the internal sphincter is the most likely cause of constipation or defecation pain in patients with ALA and that internal sphincterotomy is the cornerstone of surgical treatment.

Obstructed defecation

Obstructed defecation is one of the causes of chronic constipation. Clinical tests suggest that patients with obstructed defecation have impaired pelvic floor function. Appropriate management relies on proper identification of the underlying pathophysiology.

Evidence from dynamic integrated proctography to redefine anismus

The role of anismus in the aetiology of defective rectal evacuation was investigated by dynamic integrated proctography in 20 controls and 71 constipated patients. Normal parameters were defined and compared between 21 constipated patients with poor evacuation during proctography (< 40 per cent of contrast evacuated; group 1) and 50 who evacuated fully (> 90 per cent of contrast evacuated; group 2). Nine patients in group 1 failed to evacuate. Radiological abnormalities of the rectum were recorded in all groups but obstructed evacuation was not observed. Anismus (defined as a recruitment of puborectalis electromyogram (EMG) activity of > 50 per cent) was significantly more common in group 1 than group 2 patients (14 of 21 versus 12 of 50, P < 0.01) and present in seven of those unable to evacuate. Eight patients in group 1 failed to raise intrarectal pressure > 50 cmH2O compared with two in group 2 (P < 0.001). Six patients in group 1 demonstrated both anismus and inability to raise intrarectal pressure, which may combine to cause defective evacuation. EMG recruitment alone is insufficient to diagnose anismus. Definition should be based on three criteria: demonstration of puborectalis EMG recruitment of > 50 per cent; evidence of an adequate level of intrarectal pressure (> 50 cmH2O) on straining; and presence of defective evacuation.

The surgical management of constipation

The anal physiology laboratory plays a very important role in the selection of patients for surgical treatment for constipation. Any report which does not include reference to these methods of evaluation will not be helpful since there are several causes of constipation. The current recommended treatment for slow transit constipation is still total abdominal colectomy with ileorectal anastomosis. Treatment of pelvic floor outlet obstruction seems to be best accomplished using muscle/sensory retraining techniques since this is a functional disorder rather than an anatomical or physiological disorder. Combinations of colonic inertia, pelvic floor outlet obstruction and internal intussusception should be treated to correct the pelvic floor outlet obstruction initially, followed by correction of the colonic inertia. In this way failure will be avoided at the time of surgical treatment of the constipation.

The internal anal sphincter: mechanisms of control and its role in maintaining anal continence

The human IAS has particular structural and functional characteristics. This smooth muscle constantly generates rhythmic electrical slow waves, but no action potentials. The slow waves are linked to calcium fluxes and both are essential for mechanical activity, i.e. the ASPW. The IAS is pharmacologically characterized by the presence of alpha excitatory and beta inhibitory adrenergic receptors. Cholinergic drugs have an indirect effect through the release of an inhibitory neurotransmitter, very probably VIP, from NANC nerves. The myogenic activity of the IAS is enhanced by its extrinsic sympathetic innervation. Thus, at rest, the IAS is in a state of partial tetanus and contributes approximately 55% of the MABP. Because the IAS ring cannot be completely closed, the anal mucosa and the haemorrhoidal plexuses fill the gap. By compressing these tissues, the IAS perfectly closes the anal canal to retain not only solids but also fluid stool and gas. Acute rectal distension and rectal activity, mainly through intramural pathways, induce reflex IAS relaxation, permitting the rectal contents to be sampled by receptors in the upper anal canal while continence is temporarily maintained by EAS activity and by expansion of the haemorrhoidal cushions. There is a correlation between the volume of rectal distension and the parameters of IAS relaxation. At maximal IAS relaxation, ASPW are absent, indicating the completeness of the inhibition. Although this RAIR is not essential for defecation, insufficient relaxation may be implicated in constipation. Hyperactivity of the IAS resulting in a high MABP and AUSPW has been considered both as a cause and as an effect in haemorrhoids and anal fissure. Continence for fluids and gas is impaired if IAS activity is decreased (i.e. a low MABP), either by direct trauma or by damage of its sympathetic innervation. Severe faecal incontinence will develop when the contractility of both the IAS and the EAS is affected.