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Prolapse, Intussusception, & SRUS

Madhulika G. Varma, MD
Assistant Professor of Surgery
University of California
San Francisco, CA

Introduction Rectal prolapse, internal intussusception and solitary rectal ulcer syndrome (SRUS) comprise a spectrum of anatomical abnormalities involving descent of full- or partial-thickness rectal wall associated with pelvic floor dysfunction. These conditions, while benign, can be extremely debilitating due to the discomfort of prolapsing tissue both internally and externally, associated drainage of mucus or blood and the common occurrence of fecal incontinence or constipation. In times past, restoration of normal anatomy to treat rectal prolapse was considered a definition of success. However, the presence of over 100 operations to correct this problem indicates that the achievement of excellent outcomes is somewhat elusive. More recently, treatments aimed at addressing both functional as well as anatomic outcomes have appropriately gained greater emphasis.   Recognition of rectal prolapse as a key component of the syndrome of pelvic floor dysfunction has led to perhaps the most meaningful advance in the field— multidisciplinary treatment in the context of associated urinary and vaginal vault disorders.  Furthermore, treatment of internal intussusception and SRUS with medical and behavioral treatments has resulted in better outcomes overall with stricter patient selection for surgery. While surgery for rectal prolapse has not changed significantly, reorganization of the treatment to include a multidisciplinary approach and the advent of laparoscopic approaches has substantially furthered the field. 

RECTAL PROLAPSEEtiology and Symptoms
The etiology of rectal prolapse was a much debated issue in past centuries.  Alexis Moschcowitz proposed in 1912 that rectal prolapse was caused by a sliding herniation of the pouch of Douglas through the pelvic floor fascia into the anterior aspect of the rectum.  His theory was based on the fact that the pelvic floor of prolapse patients is mobile and unsupported, a hernia sac comprised of peritoneum from the pouch of Douglas and the rectal wall can be seen, and that other adjacent structures can occasionally be seen alongside the rectal component of the prolapse.  With the advent of defecography in 1968, however, Broden and Snellman were able to corroborate John Hunter and Albrecht von Haller’s theory from the eighteenth century that procidentia is basically a full-thickness rectal intussusception starting approximately three inches above the dentate line and extending out beyond the anal verge.  Both explanations take into consideration the weakness of the pelvic floor in rectal prolapse cases, the concept of herniation, and the observation that there are abnormal anatomic features that characterize this condition.1  Diastasis of the levator ani, an abnormally deep cul-de-sac, a redundant sigmoid colon, a patulous anal sphincter, and loss of the rectal sacral attachments are commonly described.  Interestingly, the use of defecography also highlighted the much higher prevalence of internal intussusceptions, many of which are asymptomatic. The factors that result in a patient progressing from internal intussusception to a full thickness rectal prolapse remain unknown.

Women aged 50 and older are six times as likely as men to present with rectal prolapse. Contrary to the common assumption that rectal prolapse is a consequence of multiparity, 35% of patients with rectal prolapse are nulliparous. The peak age of incidence is the seventh decade in women, whereas the relatively few men afflicted with the problem may develop prolapse at the age of 40 or less.  One striking characteristic of younger patients is their increased tendency to have autism, syndromes associated with developmental delay, and psychiatric comorbidities requiring multiple medications.2 Young male patients with procidentia also tend to report significant symptoms related to bowel function, specifically evacuation.

Approximately 50-75% of patients with rectal prolapse report fecal incontinence and 25-50% of patients will report constipation1,3-6.  Incontinence in the setting of rectal prolapse may be explained by the presence of a direct conduit (the prolapse) bypassing the sphincter mechanism, and the chronic stretch and trauma to the sphincter caused by the prolapse itself, and continuous stimulation of the rectoanal inhibitory reflex by the prolapsing tissue.  Proximal bilateral pudendal neuropathy has been demonstrated in incontinent prolapse patients and may be responsible for denervation-related atrophy of the external sphincter musculature.7   This finding is absent in normal controls.  It is speculated that pudendal nerve damage is responsible for pelvic floor and anal sphincter weakening and may be the underlying cause of a spectrum of pelvic floor disorders.  Constipation associated with prolapse may result from intussuscepting bowel in the rectum creating a blockage that is exacerbated with straining, pelvic floor dyssynergia and colonic dysmotility .4,5 

Symptoms of prolapse can progress with time.  Often, the prolapse will protrude through the anal canal only with defecation or straining and spontaneously reduce afterwards.  Then patients describe a “mass” or large “lump” that they have to push back in following defecation.  The presenting complaint is often the concurrent fecal incontinence that results from the prolapse, or a sensation of chronic moisture and mucous drainage in the perineal area.  Minimal or spontaneously reducible prolapses may progress to chronically prolapsed rectum requiring digital reduction although the timing for this is variable. Patient’s symptoms are considered severe when the prolapse occurs with walking or prolonged standing and is difficult to keep reduced.   Chronically prolapsed rectal mucosa may become thickened, ulcerated, and cause significant bleeding.  Occasionally, the presentation of rectal prolapse can be quite dramatic when the prolapsed segment becomes incarcerated below the level of the anal sphincter.  If the prolapse cannot be reduced using gentle pressure or topical sugar, emergent operative therapy is indicated in this situation.

Differential Diagnosis and Investigation
A common pitfall in the diagnosis of rectal prolapse is the potential for confusion with prolapsing internal hemorrhoids.  Usually, these two conditions are easily distinguished by clinical exam.  Close inspection of the direction of the prolapsed tissue folds will reveal that in the case of rectal prolapse, the folds are always concentric, whereas hemorrhoidal tissue develops radial invaginations defining the hemorrhoidal cushions.  Prolapsed, incarcerated hemorrhoids produce extreme pain and can be accompanied by fever and urinary retention.  Rectal prolapse on the other hand, is easily reducible and painless unless the prolapse has become incarcerated.

Prior to operative intervention, a careful history, physical examination, and colonoscopy should be performed.  Twenty to thirty-five percent of patients with rectal prolapse complain of urinary incontinence, and about 15-30% have significant vaginal vault prolapse.8,9 These symptoms will require evaluation and potential multidisciplinary surgical intervention.  If the diagnosis is suspected from the history, but not detected on physical exam, confirmation can be obtained by asking the patient to reproduce the prolapse by straining while on a toilet.  Inspection of the perineum with the patient in the sitting or squatting position is helpful for this purpose.  Full inspection of the perineum and complete anorectal exam is equally important.  A patulous anus with diminished sphincter tone is usually identified.  Proctoscopy reveals a solitary rectal ulcer on the anterior surface of the rectum in 10-15% of cases.  In the event that the prolapse is still elusive, patients can be asked to photograph the prolapse at home or if that is not possible, then defecography may reveal the problem.  Defecography may also reveal associated defects such as cystocele, vaginal vault prolapse, and enterocele that may, depending upon symptoms, require treatment as well. 

Although uncommon, a neoplasm may form the lead point for a rectal intussusception.  For this reason, and because this age group has the highest incidence of colorectal neoplasia, a colonoscopy should precede an operation.  A significant finding on colonoscopic inspection may change the operative approach. 

Anal manometry and pudendal nerve terminal motor latencies can be ordered preoperatively to further evaluate symptoms of incontinence.  However, rarely do these test results change the operative strategy.  A finding of increased nerve conduction periods (nerve damage) may have post-operative prognostic significance for continence, although more studies are required to confirm this.10-12  Those patients with evidence of nerve damage may have a higher rate of incontinence following surgical correction of the prolapse.  Unfortunately, in most studies, neither preoperative manometric findings nor nerve conduction velocities have served as reliable predictors of post-operative function.  Decreased anal squeeze or resting pressures are expected with this condition and may predate the actual development of the prolapse. 

In other cases, patients will present with rectal prolapse in the setting of lifelong severe constipation.  These patients require special consideration given the propensity for post-operative constipation with certain repairs.  Anorectal physiology testing to assess for pelvic floor dyssenergia and a transit study to rule out colonic inertia is crucial.  Patients with pelvic floor dysfunction may benefit from postoperative biofeedback therapy. Those who have evidence of surgically amenable slow transit constipation, and are continent, may be candidates for subtotal colectomy in addition to a rectopexy.  
 
Operative Repair
The number of procedures described in the literature both historically and in recent times is breathtaking.  Over 50 types of repair have been documented—most of historical interest only.   Approaches have generally included anal encirclement, mucosal resection, perineal proctosigmoidectomy, anterior resection with or without rectopexy, rectopexy alone, and a host of procedures involving the use of synthetic meshes affixed to the presacral fascia.  The apparent enthusiasm and ingenuity of surgeons in their quest to define the ideal prolapse operation only serves to highlight its elusiveness.  Two predominant general approaches, abdominal and perineal, are considered in the operative repair of rectal prolapse.   The surgical approach is dictated by the co-morbidities of the patient, the surgeon’s preference and experience, and the patient’s age.  It is generally believed that the perineal approach results in less perioperative morbidity and pain, and a reduced length of hospital stay. However, high recurrence rates and poor functional outcome as a result of resection of the rectum has prevented this approach from becoming the procedure of choice.  Although numerous operative approaches to rectal prolapse are described using both abdominal and perineal techniques, only a few are actually routinely advocated, and there have been many that are of historical interest only now.  Discussed here are procedures common in practice and routinely reported on in the literature of the past ten years. 

Abdominal Repairs Repairs with Prosthetic Materials
Most abdominal techniques generally describe mobilization of the rectum out of the true pelvis and fixation of the rectum to the sacrum.  Prosthetic materials have long been used to affix the rectum to the sacrum preventing it from forming the full-thickness intussusception leading to prolapse.  The Ripstein repair (and its many iterations) involves placement of a prosthetic mesh around the mobilized rectum with attachment of the mesh to the presacral fascia below the sacral promontory.4  Recurrence rates for this procedure range from 2.3-5%.  The procedure involves mobilizing the rectum on both sides posteriorly down to the coccyx.     Ripstein described division of the upper portion of the lateral rectal ligaments, but others advocate leaving them wholly intact as the rates of post-operative constipation are fully 50% greater in patients with divided lateral stalks in some studies.13  After mobilization of the rectum, a band of rectangular mesh is placed around its anterior aspect at the level of the peritoneal reflection, and both sides of the mesh are sutured to the presacral fascia.  Sutures are used to secure the mesh to the rectum anteriorly and the rectum is pulled upwards and posterior.  Complications include large bowel obstruction, erosion of the mesh through the bowel, ureteral injury or fibrosis, small bowel obstruction, rectovaginal fistula, and fecal impaction.  Post-operative morbidity rates are 20%, but most of these complications are minor.  Although mesh rectopexy results in significant improvement in fecal incontinence (50%), no rectal prolapse operation should be advocated as a procedure to restore continence; and patients, especially those with prolapse for more than two years, should be warned of the possibility that incontinence could persist.6  The Wells procedure is an evolution of Ripstein’s original repair using an alternative mesh technique that theoretically reduces the possibility of rectal obstruction by eliminating the anterior placement of the mesh.  The mesh is affixed to the posterior aspect of the mesorectum and then to the presacral fascia as previously described.3 Wells advocated transaction the lateral ligaments, whereas Ripstein routinely preserved them.   
Anterior Resection
 Anterior resection was described as an alternative strategy to repair prolapse in 1955, and there are some advocates of the technique.  Unfortunately, in several retrospective reviews, several shortcomings are evident.  In one review of 113 patients, the recurrence rate continued to climb after 2, 5, and 10 years to 3%, 6%, and 12% respectively with an operative morbidity of 29% including three anastomotic leaks.  Another review confirmed that with an average follow-up of 6 years, recurrence occurred in 7% of cases.  A low pelvic anastomosis in those with borderline continence may cause complete loss of control.  Careful selection of patients is necessary for this procedure, and in general, given the slightly higher recurrence rates and lack of functional advantages, it is not widely practiced. 14    
Resection Rectopexy
Resection rectopexy is a technique first described by Frykman and Goldberg in 1969 and popularized in the United States in the past 30 years.  Lack of artificial mesh, ease of operation, and resection of “redundant” sigmoid colon are the principle attractions of the procedure.  Recurrence rates are low, ranging from 2-5% and major complication rates range from 0-20% and relate either to obstruction or anastomotic leak.  Basically, the sigmoid colon and rectum are mobilized to the level of the levators.  The lateral ligaments are divided, elevated from the deep pelvis and sutured to the presacral fascia.  The mesentery of the sigmoid colon is then divided, with preservation of the inferior mesenteric artery, and a tension-free anastomosis is created.  A revised version of this procedure involves preservation of the lateral stalks and unilateral fastening of the rectal mesentery to the sacrum at the level of the sacral promontory.  Sigmoid resection is a unique and controversial feature of this procedure originally done to reduce recurrence, but subsequently found to influence function.  It seems to reduce constipation significantly in those who complain preoperatively of this symptom in some studies.15,16  Others have argued that sigmoidectomy is an inadequate operation for a chronic motility problem that affects the entire bowel and those patients should be formally evaluated preoperatively and subtotal colectomy recommended if colonic inertia is detected.   Interestingly, in patients who complain of incontinence prior to surgery, this symptom consistently improves in about 35%, even with the sigmoid resection.  There is increasing evidence that sigmoid resection may not be necessary in those who report no history of constipation and whose predominant complaint is fecal incontinence. This particular patient group does not seem to be predisposed to future constipation.17

However, for those without incontinence preoperatively, a significant postoperative complication of abdominal rectopexy is the incidence of new-onset or worsened constipation.  Fifteen percent of patients experience constipation for the first time following rectopexy and at least 50% of those who are constipated preoperatively are made worse.  The precise etiology of constipation is unclear.   While some of these difficulties are attributed to complications of the procedure such as mesh stricture, obstruction at the level of the repair, or rectal dysfunction following lateral stalk division, a subset of patients will be found to have slow-transit constipation characterizing a global motility disorder.  Some authors advocate routine preoperative transit studies to preoperatively identify these patients, but usually a good bowel habit history will suffice.  The etiology of any severe, unremitting post-operative defecation or obstruction problem should be investigated with a barium enema, colonoscopy and anorectal physiology testing.  Mechanical as well as functional reasons for constipation should be considered. 

Fiber supplementation, increased fluid intake, and stool softeners are useful in the management of functional constipation following rectal prolapse repairs of any type.  Osmotic laxatives such as Miralax may be necessary for short periods of time.

Laparoscopic Approaches 
 All abdominal approaches to rectal prolapse have been performed laparoscopically over the last decade with essentially similar results. The indications for performing a laparoscopic procedure are primarily related to the indications for an abdominal approach; patients without previous abdominal surgery are excellent candidates but pelvic surgery is not necessarily an exclusion criteria.  The laparoscopic treatment of rectal prolapse was first described in 1992 and involved a rectopexy without sigmoid resection.18 Since that time numerous series have demonstrated equivalent recurrence rates (4-8%) and morbidity (10-33%) of the laparoscopic repair when compared to open approaches, but clear benefits in terms of pain control, length of stay, and return of bowel function.3,19,20   Wound complications rates have also been found to be decreased in laparoscopic surgery for prolapse. Certainly, those who undergo rectopexy without resection are at very low risk for infection as only trocar incisions are needed. The actual surgical technique to perform laparoscopic rectopexy or resection is the same as that used for open repairs. The goals of surgery remain the same, to eradicate the full thickness rectal prolapse, improve bowel function and continence and minimize recurrence rates.3

Perineal Repairs Perineal Proctosigmoidectomy
Perineal proctosigmoidectomy was first introduced by Mikulicz in 1899 and remained the favored treatment for prolapse in Europe for many years.  Miles advocated this procedure in the United Kingdom and it was promoted in the United States by Altemeier at the University of Cincinnati. His initial study reported a recurrence rate of 3% that could not be duplicated. Patients undergoing perineal proctosigmoidectomy are general older and with significantly more co-morbidities than those who are considered for abdominal repair.  Complication rates are less than 10% and recurrence rates have been reported to be as high as 16-30%, although recent series demonstrate significantly lower recurrence rates of less than 10% with follow up times of greater than 3 years.21  Another study demonstrated that use of levatoroplasty can reduce recurrent rates from 21% to 7%.22

The Altemeier procedure combines a perineal proctosigmoidectomy with an anterior levatoroplasty.  The latter procedure is performed to correct the levator diastasis commonly associated with this condition. Theoretically, restoration of fecal continence is enhanced by this additional maneuver.  The anastomosis fashioned between the colon and the anal canal can be done with either sutures or a CEEA stapling device.  Technically, it is important to enter the peritoneal cavity and draw down and resect as much sigmoid mesentery as possible.  Failure to do so could account for high recurrence rates.  Complications include bleeding from the staple or suture line, pelvic abscess, and rarely, anastomotic leak.  Lack of an abdominal incision, reduced pain, and reduced length of hospitalization make this procedure an attractive option.23 However, since abdominal operations are now associated with less mortality and morbidity, they are the preferred method for treating rectal prolapse. The perineal approach is reserved only for elderly, frail patients with the highest operative risk, and in some centers, young men who are considered to be at risk for sexual dysfunction if a rectal mobilization is performed with an abdominal approach. 

Delorme’s Procedure
 Delorme’s procedure is a mucosal sleeve resection involves circumferential removal of redundant anal canal and distal rectal mucosa and imbrication of the muscularis layer with serial vertical sutures. It is done transanally for small prolapses where perineal proctosigmoidectomy is quite difficult.  Like perineal proctosigmoidectomy, Delorme’s procedure has higher recurrence rates than abdominal approaches in the range of 5-22%.24-26  Similarly, this procedure is advocated for those who are considered “high risk” either because of comorbidities, or to avoid risk of nerve damage.  Complications such as infection, urinary retention, bleeding, and fecal impaction occur in 6-12% of cases.  Difficult evacuation and constipation are not a prominent a feature of Delorme’s procedure, but urgency and tenesmus do occur.  Fecal incontinence is improved following surgery, as it is with many techniques.  Although restoration of function is not uniform in the series surveyed, in one of the few studies reporting postoperative manometric findings, both mean resting and squeeze pressures were significantly increased by the procedure.26

Internal Prolapse and Solitary Rectal Ulcer Syndrome Two areas of controversy related to rectal prolapse involve the treatment of solitary rectal ulcer syndrome (SRUS) and internal intussusception of the rectal mucosa.   Although identified as an “ulcer,” the gross pathology of SRUS can range from a typical crater-like ulcer with a fibrinous central depression to a polypoid lesion.  It is always located on the anterior aspect of the rectum 4-12 cm from the anal verge and is thought to correspond to the location of the puborectalis “sling.”  It is frequently, though not exclusively, associated with internal intussusception or full-thickness rectal prolapse.  Patients are typically young and female with an average age of 25 and a history of straining and difficult evacuation.
 
The rectal ulcer is usually found on proctoscopy or flexible sigmoidoscopy, and commonly presents with rectal bleeding in the setting of straining or constipation.  The etiology of SRUS remains somewhat unclear, but speculation centers on chronic ischemia.  The fold with the ulcer is thought to form the lead point of an intussusception into the anal canal.  Chronic, repeated straining or prolapse of this lead point produces ischemia, tissue breakdown, and ulceration. Possible digital self-disimpaction may also be a contributing factor.  Histology reveals a thick layer of fibrosis obliterating the lamina propria and a central fibrinous exudate.  Other common pathologic findings include the presence of mucus-filled glands misplaced in the submucosa and lined with normal colonic epithelium (i.e. colitis cystica profunda).  Differentiating SRUS from malignancy, infection, or Crohn’s disease is important, but not difficult.  The anterior location in the context of classic symptoms and pathologic findings are conclusive.

Diagnostic evaluation by defecography is the radiologic procedure of choice and usually reveals the underlying disorder.  Full-thickness rectal prolapse, internal prolapse, pelvic floor dyssynergia and thickened rectal folds are common findings.

Data regarding the treatment of this unusual disorder is retrospective and studies are small, but several common observations have been made.  In general, a third of patients with SRUS also suffer from full-thickness rectal prolapse.  Abdominal prolapse repairs have resulted in a cure rate of 80% in patients with SRUS and full-thickness rectal prolapse.  In the same study, patients treated with rectopexy for mucosal prolapse and SRUS faired far worse—only 25% of patients responded to operative intervention.18  In most studies, dietary management, pelvic floor retraining (biofeedback), and short-term use of topical anti-inflammatory medications containing mesalamine result in remission for those with either internal prolapse or pelvic muscle dysfunction.  Prompt diagnosis of the underlying problem and appropriate treatment can be difficult, but are the keys to cure.  Local excision usually results in a larger nonhealing wound and really has no role in management.  Very rarely, symptoms of severe bleeding, pain, and spasm may require a temporary diverting sigmoid colostomy.27

Internal intussusception was first described in the late 1960’s when defecagraphy was first developed and came into widespread use.  The condition is also called internal or “hidden” prolapse and is confined to the rectal mucosa and submucosa which separates from the muscularis mucosa layer and “slides” down the anal canal.  Internal intussusception can be identified in 50% of the asymptomatic population and seems to represent a normal variant.  However, there are advocates of internal prolapse repair when it is found in patients who complain of dysfunctional defecation.   Berman et al demonstrated improvement in 71% of patients undergoing Delorme, but these good results were not repeated in studies by other groups.25

Abdominal repairs such as the Ripstein have also been advocated as an alternative for symptomatic patients.  The results of these studies are not conclusive.  In patients who were repaired via an abdominal approach, only 24-38% of patients reported any sort of improvement, while a significant number experienced worsening.28  Like SRUS, the treatment of patients with incomplete or obstructed defecation should be initially evaluated with defecography.  Data does not currently support operative intervention for these disorders when internal intussusception alone is present.28

AKNOWLEDGEMENT I would like to thank Najjia N. Mahmoud, MD, University of Pennsylvania for her significant contribution to this manuscript.


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