Endometriosis surgery by laparoscopy or laparotomy can be associated with various types of intestinal complications that may occur in the immediate postoperative period or later. They include bowel anastomotic dehiscence, rectovaginal fistula, anastomotic bleeding, intra-abdominal infections, wound infections, bowel stricture, intestinal obstruction, chronic constipation, and diarrhea.
There is growing evidence that bowel injuries can be repaired by primary closure in two layers even without previous bowel preparation. Surgical treatments of deep bowel endometriosis include conservative surgery (including shaving technique or discoid resection) or a more radical approach such as bowel resection that is associated with increased complications. Good perfusion and no tension at the anastomosis site are essential when segmental resection is performed. Early recognition of bowel complications during surgery or in the immediate postoperative period is fundamental to decreased morbidity and mortality.
This chapter will deal with the prevention of bowel complication in minimally invasive surgery for endometriosis.
Highlights
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There is no evidence that mechanical bowel preparation and the postoperative use of drains decrease intestinal complications.
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Conservative surgeries for bowel endometriosis are associated with less complications compared with segmental resection.
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Delay in recognizing anastomotic leakage after colorectal surgery is associated with increased mortality.
Introduction
The estimated incidence of bowel injuries at laparoscopic surgery is one in 769 cases . This complication is often found especially during surgery for endometriosis (3–5/1000 cases) . CO 2 laser shaving procedure for deep endometriosis is associated with an incidence of mucosal bowel injury of 1.4% . When resection of deep endometriosis nodules is undertaken, bowel complications can occur in 2–3% of cases .
The most common site of gastrointestinal injury is the small intestine (47%), followed by the large intestine, the rectum, and the stomach. Approximately 55% of the injuries occur during laparoscopic entry. Other causative factors are electrosurgery (29%), during dissection or lysis of adhesions (11%), and injury due to grasping forceps or scissors (4%) . Approximately 40% of the bowel injuries are not recognized at the time of surgery . This can lead to increased morbidity and mortality associated with delayed recognition.
Avoiding intestinal injuries: endometriosis resection with no bowel involvement
In order to minimize intestinal injury, many authors have evaluated “safe” entry into the abdominal cavity. However, a Cochrane systematic review in 2012 showed that the safety of different techniques including the open technique (Hasson technique), Veress needle technique, and the direct trocar technique is comparable . When periumbilical adhesions are suspected, some surgeons prefer an open technique or an alternate entry technique through the Palmer’s point. As expected, surgeon experience and good knowledge of anatomy lead to decreased bowel injures .
In order to minimize electrosurgical injuries, a good understanding of the surgical energies is important. This includes a good knowledge of probe coupling, inadvertent tissue contact, insulation failure, and capacitive coupling. Inadvertent tissue contact and probe coupling can occur if the active electrode is not kept in the laparoscopic field at all times. Insulation failure should be detected by inspection of the instruments before use. This is especially important when using a reusable instrument. Signs of insulation failure include electromagnetic static on the monitor, abdominal wall twitching, or a reduced effect of the electrosurgical instrument . Capacitive coupling can be avoided by eliminating the use of hybrid trocars. Bipolar energy is transmitted through a device in which the active and return electrodes are in close proximity leading to a precise tissue effect, thus decreasing the spread of energy and thermal injury. By contrast, monopolar current spreads through the patient from and to the return electrode. As a result, thermal damage with monopolar cautery can extend 5 cm from the site of the injury . When surgery is done at the vicinity of intestine, electrocautery should be used cautiously .
Other measures to reduce intestinal injuries include gentle bowel handling with atraumatic graspers, careful tissue dissection, adhesiolysis only if needed, and regular inspection of the bowel after insertion and reinsertion of secondary ports . Bowel injury should be suspected in the presence of brownish fluid in the abdominal cavity and fecal odor . Intraoperative sigmoidoscopy has been suggested to diagnose a sigmoid or rectal perforation . Escape of air from the bowel after filing the abdominal cavity with fluid indicates the site of injury .
Repair of bowel laceration depends on the type of injury and the area of damage. Small injury to the large bowel with the Veress needle can be managed conservatively with observation, antibiotics, and hyperalimentation if needed . However, to date, only six cases have been reported . Extensive injury requires an exploratory laparotomy to properly assess and repair the injury. Consultation with a colorectal surgeon is recommended especially if the gynecologist has little or no experience in bowel repair.
Colon injury can be repaired by bowel resection and primary anastomosis . However, most small bowel and colonic injuries can be repaired by primary closure in two layers of 3-0 or 4-0 vicryl or polydioxanone (PDS) sutures . These sutures must be placed in the cross-sectional plane rather than in a vertical plane so that it does not narrow the lumen of the bowel . All ischemic and damaged tissues must be excised. Primary repair is associated with fewer complications such as abdominal abscess and wound dehiscence when compared to diversion colostomy . Nevertheless, a colostomy may still be necessary when the injury is extensive and the remaining tissue is not sufficiently healthy for repair due to ischemia or edema . Liberal intra-abdominal lavage, postoperative broad-spectrum antibiotics, and drainage may decrease the risk of infection . Testing for bowel integrity after repair with methylene blue or air in a fluid-filled abdomen is needed. These tests will not be helpful in the case of a small bowel injury .
Avoiding intestinal injuries: endometriosis resection with no bowel involvement
In order to minimize intestinal injury, many authors have evaluated “safe” entry into the abdominal cavity. However, a Cochrane systematic review in 2012 showed that the safety of different techniques including the open technique (Hasson technique), Veress needle technique, and the direct trocar technique is comparable . When periumbilical adhesions are suspected, some surgeons prefer an open technique or an alternate entry technique through the Palmer’s point. As expected, surgeon experience and good knowledge of anatomy lead to decreased bowel injures .
In order to minimize electrosurgical injuries, a good understanding of the surgical energies is important. This includes a good knowledge of probe coupling, inadvertent tissue contact, insulation failure, and capacitive coupling. Inadvertent tissue contact and probe coupling can occur if the active electrode is not kept in the laparoscopic field at all times. Insulation failure should be detected by inspection of the instruments before use. This is especially important when using a reusable instrument. Signs of insulation failure include electromagnetic static on the monitor, abdominal wall twitching, or a reduced effect of the electrosurgical instrument . Capacitive coupling can be avoided by eliminating the use of hybrid trocars. Bipolar energy is transmitted through a device in which the active and return electrodes are in close proximity leading to a precise tissue effect, thus decreasing the spread of energy and thermal injury. By contrast, monopolar current spreads through the patient from and to the return electrode. As a result, thermal damage with monopolar cautery can extend 5 cm from the site of the injury . When surgery is done at the vicinity of intestine, electrocautery should be used cautiously .
Other measures to reduce intestinal injuries include gentle bowel handling with atraumatic graspers, careful tissue dissection, adhesiolysis only if needed, and regular inspection of the bowel after insertion and reinsertion of secondary ports . Bowel injury should be suspected in the presence of brownish fluid in the abdominal cavity and fecal odor . Intraoperative sigmoidoscopy has been suggested to diagnose a sigmoid or rectal perforation . Escape of air from the bowel after filing the abdominal cavity with fluid indicates the site of injury .
Repair of bowel laceration depends on the type of injury and the area of damage. Small injury to the large bowel with the Veress needle can be managed conservatively with observation, antibiotics, and hyperalimentation if needed . However, to date, only six cases have been reported . Extensive injury requires an exploratory laparotomy to properly assess and repair the injury. Consultation with a colorectal surgeon is recommended especially if the gynecologist has little or no experience in bowel repair.
Colon injury can be repaired by bowel resection and primary anastomosis . However, most small bowel and colonic injuries can be repaired by primary closure in two layers of 3-0 or 4-0 vicryl or polydioxanone (PDS) sutures . These sutures must be placed in the cross-sectional plane rather than in a vertical plane so that it does not narrow the lumen of the bowel . All ischemic and damaged tissues must be excised. Primary repair is associated with fewer complications such as abdominal abscess and wound dehiscence when compared to diversion colostomy . Nevertheless, a colostomy may still be necessary when the injury is extensive and the remaining tissue is not sufficiently healthy for repair due to ischemia or edema . Liberal intra-abdominal lavage, postoperative broad-spectrum antibiotics, and drainage may decrease the risk of infection . Testing for bowel integrity after repair with methylene blue or air in a fluid-filled abdomen is needed. These tests will not be helpful in the case of a small bowel injury .
Avoiding intestinal complications: endometriosis resection with bowel involvement
Resection of bowel endometriosis could lead to various types of intestinal complications that can occur in the immediate postoperative period (usually the first two weeks after surgery) or later. The early complications are anastomotic dehiscence and bleeding, rectovaginal fistula, and intra-abdominal and wound infections. Late complications include bowel stricture, intestinal obstruction or subocclusion by adhesions, bowel disorders such as chronic constipation and difficult intestinal emptying (secondary to trauma to the pelvic nerves), and chronic diarrhea. These complications tend to occur after right colectomy with ileocecal valve resection.
In a systematic review of 30 articles on the complications of bowel resection for endometriosis, the overall complication rate was 22.2% . Severe intestinal complications occurred in 6.4% of the cases. These include anastomotic leakage (1.9%), fistula (1.8%), and severe bowel obstruction (2.7%). Minor complications occurred in 14.7% of women, including temporary bowel dysfunction (3.6%) and bladder dysfunction (8.1%). Some measures should be implemented in order to prevent or minimize those complications ( Fig. 1 ).
Before surgery
Clinical and nutritional evaluation and correction of comorbidities
Minimizing intestinal complications after bowel surgery for deep endometriosis should start preoperatively. Patients should be in good clinical and nutritional status and any possible comorbidities, such as hypertension or diabetes, or poor nutrition should be first corrected .
Patients with inflammatory bowel disease (IBD) or colorectal cancer are usually at a certain degree of malnourishment, a condition that is not usually found in women with endometriosis. Yet, endometriosis is associated with some immunological alterations which are also present in patients with IBD. In fact, women with endometriosis might also have IBD . Patients with low albumin (3.0–3.5 g / dL) and total protein , and those with ASA (American Society for Anesthesiology) score ≥3 are at an increased risk of anastomotic leakage . Women with endometriosis are usually young and do not have a high ASA score or severe comorbidities.
Bowel preparation
Mechanical bowel preparation
Several products have been used for bowel preparation, including nonabsorbable polyethylene glycol (GoLYTELY®) or a combination of laxatives and purgatives. Oral sodium phosphate is also commonly used, but could lead to decreased renal function. Its use should be only for patients <60 years of age, which includes almost all women with endometriosis . Mannitol has also been used. However, it is metabolized by intestinal flora to produce hydrogen gas. Theoretically, the use of electrocautery can lead to an explosion.
Resection of the small bowel, the right colon, and ileocecal valve may be necessary in some cases of endometriosis. Whether bowel preparation is needed for endometriosis colorectal surgery is still unclear. Several studies have suggested that mechanical bowel preparation may be associated with an increased risk of anastomotic leakage and infectious complications . A Cochrane systematic review in 2011 including 18 studies with 5805 participants showed that leakage of bowel anastomosis, mortality rate, peritonitis, need for reoperation, wound infection, and other non-abdominal complications among those with and without bowel preparation were comparable . Similar results were found in a study of laparoscopic colorectal resection with primary anastomosis .
Yet, a certain group of patients undergoing elective colorectal resection can benefit from mechanical bowel preparation. In a randomized study including cases of low anastomosis (<7 cm from the anal verge), the authors found that compared to a single rectal phosphate enema, mechanical bowel preparation was associated with a decreased rate of anastomotic leakage .
Antibiotics
A Cochrane review on the use of antibiotics before elective colorectal surgery involving 260 trials and 43,451 participants showed that compared to placebo, prophylactic antibiotics decreased the incidence of wound infection (relative risk (RR): 0.34; 95% confidence interval (CI): 0.28–0.41) by 75% . In another study of left colon resection, the use of mechanical bowel preparation with oral antibiotics was associated with less postoperative abdominal infections, anastomotic leakage, and wound infection compared to no preparation .
One drawback of the use of prophylactic antibiotics is the risk of Clostridium difficile colitis. It was first identified with the use of clindamycin, but may occur with any type of antibiotics. The incidence of C. difficile infection after gastrointestinal elective surgery is 1.2% .
During surgery
Avoidance of segmental resection
The type of surgery for bowel endometriosis should be determined preoperatively with abdominal imaging including magnetic resonance imaging (MRI) and transvaginal ultrasound . There are a few techniques. Donnez et al. performed 500 cases using the shaving technique in which excision of the lesion is performed without entering the bowel . The average size of the intestinal lesions was 3.4 cm (range: 2–6 cm). Entry into the bowel was encountered in seven cases. There were no intestinal complications such as dehiscence or fistula. In a median follow-up of 3.1 years, 221 (57%) women had spontaneous pregnancy. Recurrence occurred in 39 women (7.8%). The possibility of long-term complications with the shaving technique is potentially decreased due to minimal nerve injury.
Another technique is discoid resection where the entire thickness of the bowel wall is excised . Discoid resection with circular stapler could be done faster than manual excision and has been the preferred technique since 2001 . Compared to segmental resection, the use of circular stapler is associated with shorter operating time, less blood loss, less intestinal complications, acceptable pregnancy rates, and less nerve injury . Discoid resection is usually performed for nodules of 2–3 cm in size . Yet, nodules of size 4–5 cm can also be removed with double circular stapler technique developed by Pinho Oliveira et al. The use of this technique avoids segmental resection and may reduce intestinal complications. Due to the size of the lesion, only a part of the nodule is included in the first stapling ( Fig. 2 ). The residual nodule is then invaginated into the second circular stapler inserted through the rectum. Accordingly, the nodule is removed together with the first staple line ( Fig. 3 ). In the first 11 cases, no dehiscence, fistulas, or bowel stenosis was encountered. The median operative time was lower compared to segmental resection (100 vs. 150 min, p = 0.04).
Larger lesions (>5 cm) require segmental resection. Segmental resection is associated with increased morbidity compared to the more conservative techniques such as shaving and discoid resection likely due to ischemia and increased tension in the anastomosis .
Anastomosis perfusion
For a successful outcome after intestinal anastomosis, the margin of the two bowel segments should have adequate blood supply. The results of animal studies suggest that hypoxia increases the risk of intestinal disruption . Vignali et al. evaluated 55 patients who underwent colorectal resection. There were 14.5% anastomotic leaks with a positive correlation between the reduction in the rectal microperfusion and the presence of leakage .
All studies confirmed the importance of an adequate blood supply to the success of anastomosis. However, the practical applications of these findings are difficult to be established. A surgeon’s perception on good-quality perfusion is still based on the color of the intestinal segment and the bleeding of the intestinal mucosa at the site of anastomosis.
Anastomotic tension
The association between tension at the anastomosis site and leak of bowel anastomosis has not been well evaluated. Experimental models focus more on the pressure needed to produce a leak than the effects of tension on the anastomosis site . In a dog model, the tension on anastomosis of small intestine produced a lesser effect on the submucosal blood flow when compared to colonic anastomosis. This could be due to an increased relaxation of the mesentery at small bowel anastomosis compared to that of the colon .
Intestinal segments most affected in deep endometriosis are the rectum and the sigmoid where there is an increased risk of tension in the anastomosis. In the case of a high-tension anastomosis, the surgeon should perform an adequate intestinal mobilization even up to the splenic flexure . Although extensive resections are not frequent in patients with endometriosis, the surgeon must be familiar with this type of mobilization, especially in the presence of multifocal intestinal disease.
Anastomosis technique
The most common segmental resection technique in minimally invasive surgery is the classic double stapling. It involves linear stapling below the lesion until complete bowel transection followed by anastomosis with the circular stapler. The choice of an appropriate stapler is important to reduce complications. The linear cartridge with tall staples (usually green cartridge of 4.1 mm) should be used for thick tissues such as the rectum. The shorter staples (usually white cartridge of 2.5 mm) are used for blood vessels or tissues with thin walls such as the small intestine (usually blue cartridge of 3.5 mm). The use of short staples for tissues with thick walls may predispose to anastomotic leak due to incomplete closure. The choice of tall staples for thin tissues may lead to inadequate coaptation, thus increasing the risk of hematomas with subsequent dehiscence.
Circular staplers are available in different diameters. Improper use of a circular stapler with a small outer diameter may lead to bowel stenosis that can occur in up to 30% of the cases . Strictures tend to occur more with the use of 28-mm-diameter circular stapler compared to that with a 31-mm stapler. Villanueva-Sáenz et al. and Asari et al. suggest the use of a 33-mm-circular stapler for colorectal anastomosis .
Inferior mesenteric artery ligation
A crucial step for the success of any anastomosis is to ensure adequate blood supply and absence of tension on the anastomosis Colon mobilization may be needed to minimize tension and it might require ligation of the inferior mesenteric artery (IMA) or its branches. The length of the intestine to be mobilized depends on the level of the ligation. It can be done caudal to the origin of the left colic artery or at its aortic origin. The anastomotic leakage rate with high and low ligation is comparable (10.2 vs. 9.9%) . Adequate mobilization of the splenic flexure often allows the preservation of the left colic artery .
Operative time/Blood loss
The level of difficulty of the procedure is reflected in the operative time, blood loss, and blood transfusion rate . Telem et al. conducted a case–control study in patients with cancer or IBD. They included 90 patients with anastomotic leakage and 180 without it. The rate of anastomotic leakage is associated with an operative time >200 min, intraoperative blood loss >200 ml, and the need for blood transfusion (odds ratio, OR: 22.1) with a positive predict value of 91% .
Omental flap in anastomosis
Another complication of bowel anastomosis is rectovaginal fistula. It can also occur with the excision of rectovaginal endometriosis nodule with entry into both the vagina and rectum. In such cases, the vaginal and rectal sutures stay in contact with each other.
Some surgeons believe that covering anastomosis with an omental flap (omentoplasty) reduces the incidence of anastomotic leakage by increasing neovascularization. The procedure involves transposition of vascularized pedicle of omentum to cover the anastomosis .
In a meta-analysis, the authors included three randomized studies of the use of omentoplasty in colorectal anastomosis. They found that the rates of anastomotic leakage with and without omentoplasty were comparable (5.0 and 8.4%) .
Fibrin glue in anastomosis
Low (<8 cm from the anal verge) and ultra-low bowel anastomosis (<5 cm from the anal verge) are at a greatest risk of complication possibly due to the tenuous vascularization of this area and to increased intraluminal pressure. The use of fibrin glue in bowel anastomosis has been shown to decrease anastomotic leakage . In a randomized study of 223 patients with colorectal anastomosis, the leakage rate in the fibrin glue group and the control group was 5.8% and 10.9%, respectively . However, it does not reach significance .
However, a multicenter randomized study demonstrated that the use of fibrin glue for different types of intestinal anastomosis was associated with decreased anastomotic dehiscence. Fifty-two patients were randomized to the fibrin glue group and 52 to the control group. Colorectal anastomosis was performed in 41 patients (19 with glue and 22 without) and leaks occurred in 14 (34%). Anastomotic leakage was observed in seven cases in the fibrin glue group (13.4%) and 15 cases in the control group (28.8%), p = 0.04 for all the anastomotic sites . The number of cases is very small to reach a definite conclusion.
The use of drain
The use of a drain after colorectal surgery for endometriosis is a controversial issue. The purpose of a drain is to prevent the accumulation of fluid and blood in the pelvis and in the presacral space. Theoretically, it would allow early detection of leaks by fecaloid or purulent output through the drain. However, most peritonitis occur in the absence of fistula. A randomized study suggests that draining does not facilitate the early detection of anastomotic complications. The fecaloid or purulent material can escape from either the drain or the surgical wound .
Studies on anastomotic leakage have shown mixed results. Some reports show that the rate of anastomotic leakage with or without the drain is similar, while others demonstrate that the use of the drain decreases the rate of leakage.
Leak tests
Anastomotic leakage could be tested during surgery by injecting air or liquid (usually methylene blue) into the rectum under pressure in a fluid-filled abdomen, while the bowel is occluded proximal to the anastomosis. Air or contrast leak indicates an inadequate anastomosis .
The question arises regarding the measures to be undertaken if the surgeon finds a positive leak test result during surgery. Ricciardi et al. analyzed 825 colorectal resections and found 8% air leakage. Among patients who underwent anastomosis, anastomotic leakage was observed in 7.7% who tested positive, 3.8% who tested negative, and 8.1% who were not tested. ( p < 0.03). When the surgeon merely sutured the anastomotic defect that tested positive for air leakage, the anastomotic leakage rate after surgery was 12.1%. No leakage was encountered when anastomosis was completely redone or when a protective stoma was made .
Diverting colostomy and ileostomy
The purpose of diverting ostomy is to decrease the intestinal contents arriving at the area of anastomosis and allows the patient to feed earlier . The common ostomies are ileostomy and colostomy. Loop ileostomy is usually done at the ileum and loop colostomy at the transverse or descending colon. Two meta-analyses suggest that ileostomy is preferable over colostomy; it is associated with less complications of surgical wound (hernias and infections) after reversal. However, the output volume of ileostomy is high that may cause electrolyte disturbances. In addition, the enteric content is corrosive to the skin.
The use of a protective stoma to decrease the colorectal anastomotic leakage is debatable. After analyzing six randomized studies, Montedori et al. concluded that the use of protective stoma was significantly associated with less anastomotic leakage (RR: 0.33; 95% CI: 0.21–0.53) and less chance of reoperation (RR 0.23; 95% CI: 0.12–0.42) .
Note that women with intestinal endometriosis do not have the same profile as patients with colon cancer. They are usually healthy young women without nutritional problems or previous radiotherapy. Intestinal complications are less expected in this group, and the protective stoma should be used judiciously. However, in women with colorectal surgery for endometriosis, ileostomy protection seems to be essential for lesions <5 cm from the anal verge .
Adhesion barrier
Adhesions are frequent complications of abdominal surgery . Many adhesion-reducing substances and barriers have been studied. Some randomized studies suggest that the use of hyaluronate carboxymethylcellulose (Seprafilm®, Sanofi, Paris, France) after colorectal surgery reduces the incidence of reoperations for adhesion-related complication (RR: 0.49, 95% CI: 0.28–0.88) . Its use, however has been associated with an increased anastomotic leakage rate.
After surgery
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1 Supplemental oxygen
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2 Fast track
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3 Early recognition of complications
Supplemental oxygen
Studies in the animal model showed that oxygen supplementation could be beneficial on the quality of the anastomosis . However, there has been no clinical studies showing its superiority.
Fast track
Fast track protocols or enhanced recovery after surgery (ERAS) involve anesthesia care, adequate analgesia, reduction in endocrine-metabolic, and inflammatory response related to surgical trauma, control of the fluid balance in the perioperative period, nausea prevention, prophylaxis for venous thromboembolism, early nutrition, and postoperative mobilization . The purpose is to reduce the complications and medical costs .
Two randomized studies showed that perioperative fluid restriction enhanced tissue healing and decreasing the risks of intestinal anastomosis .
Early recognition of complications
A delay in recognizing anastomotic leakage after colorectal surgery is associated with increased mortality . However, its clinical presentation is not specific . The most commonly used technique to detect anastomotic leakage is by abdominal computed tomography (CT) scan. However, it has low sensitivity.
Several authors studied the C-reactive protein (CRP) levels in the subclinical stage of anastomotic leakage. CRP levels rapidly increase after the beginning of the inflammatory process . A meta-analysis including six studies involving 1832 patients showed that the CRP levels in the fourth postoperative day had a sensitivity of 68%, specificity of 83%, and a negative predictive value of 89% for infectious complications .
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