The failed gastrointestinal anastomosis: an inevitable catastrophe?

Anastomotic leakage as a risk factor for the long-term outcome after curative resection of colon cancer

AIMS

Long-term outcome for curative colon cancer surgery may be impaired by anastomotic leakage, but most studies regard colon and rectal cancer patients as one group. The aim of this study was to determine whether anastomotic leakage following potentially curative resection for colon cancer is a risk factor for postoperative mortality and for long-term survival.

PATIENTS AND METHODS

Medical records of a cohort of 440 consecutive patients undergoing 445 curative resections for explicit colon cancer with primary anastomosis above the peritoneal reflection were reviewed. Therefore patients with rectal cancer were not included. Diagnosis of leakage was made by clinical features or abdominal CT-scans.

RESULTS

The study population consisted of 266 men and the mean age was 68.6 years. Median follow-up time was 66.5 months. Anastomotic leakage occurred in 12 patients. Four of these died within 30 days after surgery compared to 15 of the remaining 428 patients without leakage (p<0.001). The 5-year overall survival rate was 25% in patients with anastomotic leakage compared to 61.2% in those without leakage (p<0.001). Excluding 30-day mortality, respective values were 33.3 and 63.7% (p=0.02).

CONCLUSION

Although anastomotic failure after colon cancer surgery is rare, it is a very severe complication that not only impairs the perioperative morbidity and mortality but also significantly influences the long-term outcome negatively.

[Perioperative fluid management: an analysis of the present situation]

Optimal perioperative fluid management is still controversial. Besides well known perioperative hypovolaemia, hypervolaemia has an influence on perioperative morbidity and mortality, particularly with regard to the patient's medical history, a reduced cardiac and pulmonal function and the operation itself. The concepts of preoperative, intraoperative and postoperative fluid administration are neither adequately validated, nor sufficiently integrated into a perioperative concept. At the present, moderate fluid administration to improve preoperative and postoperative outcome is safe in minor or medium surgical procedures. High-risk surgical patients benefit from a time-oriented or/and goal-oriented monitored fluid therapy. In the past only little attention has been concentrated on postoperative fluid management, but may be stimulated by the new concepts of fast track surgery.

The effects of vasopressors on perfusion of gastric graft after esophagectomy. An experimental study

AIMS

To evaluate the impact of the perioperative administration of norepinephrine on the perfusion of the esophageal graft.

METHODS

This is an experimental study. Six swine underwent transhiatal esophagectomy; the stomach was used to replace the resected esophagus. We provoked hemorrhagic shock to the animals and then we administered noradrenaline to restore the blood pressure. We monitored the graft perfusion perioperatively using the technique of microdialysis.

RESULTS

In all animals, the graft experienced severe hypoperfusion after the administration of noradrenaline that was statistically significant.

CONCLUSIONS

Our data support the hypothesis that norepinephrine should be used with extreme caution in the perioperative setting after esophagectomy. Further studies, however, will be required to evaluate the clinical significance of this finding.

Clinical significance of closed lumen pressurized perfusion in Dixon operation in detecting anastomotic leakage

AIM: To analyze the clinical value of closed gut lumen pressurized perfusion (CGLPP) in the detection of anastomotic leakage.

METHODS: A total of 35 cases were collected. After the enteroenterostomy was completed, the intestine was clamped at the upper extremity 5 cm away from the anastomotic stoma. In addition, one Foley urinary catheter (22-24 in size) was used via the anus and water was instilled into the catheter balloon to make the enteric cavity closed. Via the urinary catheter, methylthioninium chloride diluent was infused into the enteric cavity to observe whether anastomotic leakage existed.

RESULTS: During the pressurized perfusion, anastomotic leakage was found in 2 cases (5%), and repaired immediately. After following up for 6-12 mo, no anastomotic fistula and stricture occurred. All the cases had no reccurence or metastasis.

CONCLUSION: Application of CGLPP in Dixon operation may help to detect anastomotic leakage and prevent anastomotic injury.

Polypropylene mesh covered colonic anastomosis. Results of a new anastomosis technique

BACKGROUND

The morbidity and mortality rates of anastomosis leakage of the gastrointestinal system, are high. In this study we covered the colonic anastomosis with polypropylene mesh on the safety of the anastomosis was investigated.

METHODS

Twenty female albino rabbits were divided into two groups. First of all, a segmental colon resection was performed in both the groups and a single layer of anastomosis was made. In addition, a polypropylene mesh as long as the circumference of the anastomosis in the study group. All the rabbits were sacrificed on the 10th postoperative day and the explosion pressure of the anastomosis, histopathological investigation of the anastomotic contour, and peritoneal adhesion were compared.

RESULTS

The anastomoses of all the subjects in the control group had exploded and the average explosion pressure was 149 +/- 16 mmHg. However, in the study group, the anastomoses did not explode in nine (90%) of the subjects, whereas it exploded in only one (10%) with a pressure of 260 mmHg. The average explosion pressure in the study group was 315 +/- 30 mmHg (p < 0.0001). No significant difference was established between the groups according to the histopathological classification of the anastomotic contour performed according to the Ehrlich-Hunt model (p > 0.05). Peritoneal adhesions of the groups is not statistically different (p > 0.05).

CONCLUSION

During the short follow-up period, this new technique significantly increased the safety of the anastomosis, moreover it did not cause any increase in peritoneal adhesions. This success has most probably occurred as a result of the external mechanical support to the anastomosis.

Preoperative laparoscopic ligation of the left gastric vessels in preparation for esophagectomy

Anastomotic leak is a major cause for morbidity after esophagectomy. The cause is believed to be ischemia of the gastric conduit. Preoperative embolization of the left gastric vessels in preparation for esophagectomy has been shown to improve collateral blood flow of the gastric conduit and may reduce the frequency of anastomotic dehiscence after esophagectomy. This report describes the technique of laparoscopic division of the left gastric vessels in 9 patients who underwent pre-esophagectomy staging laparoscopy. Our initial experience demonstrates that laparoscopic ligation of the left gastric artery is a safe alternative to embolization and can be performed in conjunction with staging laparoscopy for patients with esophageal cancer.

Outcomes of right- compared with left-side colectomy

Right colon resections are perceived as less morbid than left colon resections. The purpose of this study was to determine the differences in outcomes between right-and left-side colon resections. We reviewed 420 consecutive open colectomies over 4 years. Patient demographics, surgical indications, intraoperative variables, and outcomes were collected. Two hundred twenty-three right colectomies (RCs) were compared with 197 left colectomies (LCs). RCs were more often required for cancer (111 vs 65, P < .001) and LCs for diverticular disease (10 vs 90, P < .001). LCs were more often performed emergently (36% vs 23%, P = .004) and required longer mean operative times (149 minutes vs 130 minutes, P = .004). Complications and mortality in the two groups were equal statistically. In the emergent colectomy subset, LCs were associated with greater intraoperative blood loss (315 vs 201 mL, P = .02) but fewer complications (11% vs 17%, P = .003).

Postoperative complications and functional results after subtotal gastrectomy with Billroth II reconstruction for primary gastric cancer

Subtotal gastrectomy is considered the preferred treatment for gastric cancer with antral location. The aim of this study was to assess the incidence of early postoperative complications and late functional results in patients who underwent subtotal gastrectomy with Billroth II reconstruction for primary gastric adenocarcinoma. The results of 310 patients were analyzed with regard to postoperative complications and death rates. Functional results as they relate to the gastric resection were evaluated in 195 disease-free patients. Of the 310 patients, 77 developed postoperative general and surgical complications (24.8%) and 13 consequently died (in-hospital mortality: 4.2%). Although infrequent (6 cases, 1.9%), anastomotic leak was the most serious complication (4 cases died during the postoperative phase). Considering functional results, weight loss continued for the first trimester after surgery, after which it stabilized. Loss of appetite was rarely observed; early after the operation the majority of patients were consuming a normal diet and regularly consumed less than five meals per day (83.6%). Dumping syndrome was uncommon and usually resolved within one year (12.3% at three months, 9.5% after one year, 5.2% after two years). On the other hand, postprandial abdominal fullness was frequently observed (43.1% at three months, 36.1% after one year, 21.3% after three years, and 16.5% after five years). Billroth II reconstruction after subtotal gastrectomy is associated with a limited risk of anastomotic complications. Anastomotic leak, although infrequent, is a life-threatening complaint and requires prompt recognition and aggressive surgical treatment. The incidence of late complications was low and the majority of patients recovered from them within one year after surgery, although the occurrence of postprandial abdominal fullness was not completely irrelevant.

Interactions of polysaccharide-based tissue adhesives with clinically relevant fibroblast and macrophage cell lines

The effects of polysaccharide-based tissue adhesives on cell survival and inflammatory cell activation were determined using in vitro mouse cell cultures. Cytotoxicity of tissue adhesives was evaluated by placing adhesives in direct contact with 3T3 fibroblast cells. Polysaccharide-based tissue adhesives composed of dextran aldehyde and star PEG amine were non-cytotoxic to fibroblasts; in contrast, a commercial adhesive composed of 2-octyl cyanoacrylate was highly cytotoxic to fibroblasts. The inflammatory potential of tissue adhesives was evaluated by exposing J774 macrophage cells to adhesives, and measuring TNF-alpha release from macrophages. Polysaccharide-based tissue adhesives did not elicit inflammatory TNF-alpha release from macrophages. These results suggest that polysaccharide-based tissue adhesives are non-cytotoxic and non-inflammatory; the results are therefore significant in the design of in vitro cell culture systems to study biomaterials.

Perioperative Vasopressors Are Associated with an Increased Risk of Gastrointestinal Anastomotic Leakage

BACKGROUND

The purpose of this study was to investigate the effect of vasopressors on gastrointestinal (GI) anastomotic leaks. Vasopressors are commonly used in surgical patients admitted to the intensive care unit (ICU) and their effects on GI anastomotic integrity are unknown.

PATIENTS AND METHODS

Surgical patients admitted to the ICU in our tertiary university hospital following the creation of a GI anastomosis were studied by a retrospective chart analysis for anastomotic leaks and complications

RESULTS

A total of 223 patients with 259 GI anastomoses, mostly for cancer, were admitted to the ICU immediately after surgery. Twenty-two patients developed anastomotic leaks (9.9%). The two groups (leak versus no-leak) had similar demographics, surgery type and indication, type of anastomosis, co-morbidities, cancer, steroid use, blood transfusion, drains, and epidural catheters. Vasopressor use was associated with increased anastomotic leakage (p = 0.02, OR 3.25). Multiple vasopressors and prolonged exposure caused even higher leaking rates. This effect was independent of the medical status and operative morbidity (APACHE II, POSSUM). Blood pressure preceding vasopressor use was similar in both groups. Vasopressors might have been occasionally used to treat hypovolemia. Patients with leaks had higher reoperation rates (41% versus 1%, p < 0.0001) and mortality (21% versus 4%, p = 0.002).

CONCLUSIONS

Vasopressors appear to increase anastomotic leaks threefold, independent of clinical/surgical status or hypotension. Evidence-based guidelines are warranted for the optimal use of vasopressors in postoperative patients admitted to the ICU.

Influência da cola Bioglue® na deiscência de anastomose colônica: estudo experimental

A grande parte da morbimortalidade associada com a cirurgia colorretal, é associada com a deiscência anastomótica. Trabalhos experimentais sobre a utilidade de adesivos tissulares nas anastomoses colônicas são controversos, assim como estudos clínicos prospectivos randomizados são ausentes. O adesivo cirúrgico BioGlue®, formado por dois componentes - albumina sérica bovina purificada e glutaraldeído, forma uma ligação co-valente entre esses dois componentes e as proteínas teciduais no local de aplicação. O objetivo do estudo é avaliar a eficácia da BioGlue® na prevenção da deiscência anastomótica colônica em ratos. Foram utilizados 30 ratos machos da raça Wistar albino. A anastomose colocolônica foi confeccionada com sutura em pontos separados com polipropileno 5-0 (grupo 1) e aplicação da cola BioGlue® envolvendo a anastomose (grupo 2). Avaliaram-se a formação e extensão das aderências, a pressão de ruptura nas anastomoses e as alterações histológicas. Apenas um animal do grupo 1 (7%) faleceu, sendo constatada na necropsia, obstrução intestinal com grande distensão de alças. A mortalidade no grupo 2, por outro lado, foi de 10 animais (67%), sendo observado: distensão de alças intestinais, vazamento anastomótico e, em algumas situações, franca peritonite fecal por deiscência quase que total da anastomose. O presente trabalho nos permitiu concluir que, o uso da Bioglue® nas anastomoses colônicas realizadas em ratos, promoveu um aumento na morbimortalidade que foi estatisticamente significante comparado à sutura convencional.

Postoperative Ileus-Related Morbidity Profile in Patients Treated with Alvimopan after Bowel Resection

BACKGROUND

Postoperative ileus (POI), an interruption of coordinated bowel motility after operation, is exacerbated by opioids used to manage pain. Alvimopan, a peripherally acting mu-opioid receptor antagonist, accelerated gastrointestinal (GI) recovery after bowel resection in randomized, double-blind, placebo-controlled, multicenter phase III POI trials. The effect of alvimopan on POI-related morbidity for patients who underwent bowel resection was evaluated in a post-hoc analysis.

STUDY DESIGN

Incidence of POI-related postoperative morbidity (postoperative nasogastric tube insertion or POI-related prolonged hospital stay or readmission) was analyzed in four North American trials for placebo or alvimopan 12 mg administered 30 minutes or more preoperatively and twice daily postoperatively until hospital discharge (7 or fewer postoperative days). GI-related adverse events and opioid consumption were summarized for each treatment. Estimations of odds ratios of alvimopan to placebo and number needed to treat (NNT) to prevent one patient from experiencing an event of POI-related morbidity were derived from the analysis.

RESULTS

Patients receiving alvimopan 12 mg were less likely to experience POI-related morbidity than patients receiving placebo (odds ratio = 0.44, p < 0.001). Fewer patients receiving alvimopan (alvimopan, 7.6%; placebo, 15.8%; NNT = 12) experienced POI-related morbidity. There was a lower incidence of postoperative nasogastric tube insertion, and other GI-related adverse events on postoperative days 3 to 6 in the alvimopan group than the placebo group. Opioid consumption was comparable between groups.

CONCLUSIONS

Alvimopan 12 mg was associated with reduced POI-related morbidity compared with placebo, without compromising opioid-based analgesia in patients undergoing bowel resection. Relatively low NNTs are clinically meaningful and reinforce the potential benefits of alvimopan for the patient and health care system.

Anastomotic leaks after intestinal anastomosis: it's later than you think

PURPOSE

Anastomotic leaks are among the most dreaded complications after colorectal surgery. However, problems with definitions and the retrospective nature of previous analyses have been major limitations. We sought to use a prospective database to define the true incidence and presentation of anastomotic leakage after intestinal anastomosis.

METHODS

A prospective database of two colorectal surgeons was reviewed over a 10-year period (1995-2004). The incidence of leak by surgical site, timing of diagnosis, method of detection, and treatment was noted. Complications were entered prospectively by a nurse practitioner directly involved in patient care. Standardized criteria for diagnosis were used. A logistic regression model was used to discriminate statistical variation.

RESULTS

A total of 1223 patients underwent resection and anastomosis during the study period. Mean age was 59.1 years. Leaks occurred in 33 patients (2.7%). Diagnosis was made a mean of 12.7 days postoperatively, including four beyond 30 days (12.1%). There was no difference in leak rate by surgeon (3.6% vs. 2.2%; P = 0.08). The leak rate was similar by surgical site except for a markedly increased leak rate with ileorectal anastomosis (P = 0.001). Twelve leaks were diagnosed clinically versus 21 radiographically. Contrast enema correctly identified only 4 of 10 leaks, whereas CT correctly identified 17 of 19. A total of 14 of 33 (42%) patients had their leak diagnosed only after readmission. Fifteen patients required fecal diversion, whereas 18 could be managed nonoperatively.

CONCLUSIONS

Anastomotic leaks are frequently diagnosed late in the postoperative period and often after initial hospital discharge, highlighting the importance of prospective data entry and adequate follow-up. CT scan is the preferred diagnostic modality when imaging is required. More than half of leaks can be managed without fecal diversion.

Anastomotic leaks: what is the best diagnostic imaging study?

PURPOSE

Postoperative anastomotic leaks are one of the most devastating consequences of colorectal surgery. Diagnostic imaging for upper gastrointestinal anastomotic leaks has been evaluated and reported on extensively. No study has compared the utility and effectiveness of CT scans and water-soluble enemas for the identification of postoperative lower gastrointestinal anastomotic leaks. The present study was designed to evaluate and compare these two common radiographic imaging modalities in detecting lower gastrointestinal anastomotic leaks.

METHODS

A retrospective chart review was performed that identified 36 patients during a seven-year period who underwent reoperative surgery for a lower gastrointestinal anastomotic leak. Patient's imaging studies were classified as positive if extravasation of contrast material was demonstrated. When negative, a study was retrospectively reviewed in an attempt to identify findings suggestive of an anastomotic leak.

RESULTS

There were 36 patients identified with a postoperative lower gastrointestinal leak requiring surgical intervention. There were 28 of 36 patients (78 percent) re-explored on the basis of a radiologic study demonstrating an anastomotic leak. A total of 27 CT scans were performed, of which 4 (14.8 percent) were considered positive for an anastomotic leak. On review of the remaining negative CT scans, nine (33.3 percent) were considered descriptive positive with a large amount of fluid or air in the peritoneal cavity but without obvious extravasation of contrast. Eighteen patients were evaluated with a water-soluble enema and 15 (83.3 percent) demonstrated extravasation of contrast material. In the 26 patients with a distal anastomotic leak, 17 water-soluble enemas were performed, with 15 (88 percent) demonstrating a leak. In contrast, only 2 of 17 (12 percent) CT scans were positive in this group of patients (P < 0.001). There were ten patients who initially had a CT scan followed by a water-soluble enema. Of these patients, eight of nine (88 percent) initially had a negative CT scan but were considered to be clinically suspicious of having an anastomotic leak and subsequently had a leak demonstrated on a water-soluble enema.

CONCLUSIONS

Early intervention in patients who develop an anastomotic leak can be shown to improve the ultimate outcome, especially with respect to mortality. It is usually necessary to obtain objective tests of anastomotic integrity because of the nonspecificity of clinical signs. Our study supported the superiority of water-soluble enema to CT imaging in patients in whom both modalities were used. This difference was most pronounced for distal anastomotic leaks, whereas no radiologic imaging study proved effective in evaluating proximal anastomoses.

Management of intrathoracic leaks following esophagectomy

Mortality from esophageal anastomotic leaks has declined dramatically in contemporary practice, which seems to be caused by a management strategy that includes observation of contained, asymptomatic leaks, operation on uncontained leaks using muscle flaps to reinforce the leak repair, and percutaneous drainage of contained, symptomatic leaks. With further advances in surgical technique, critical care, and multimodality treatment, this trend is likely to continue.

Changes in gelatinase activity in the gastrointestinal tract after anastomotic construction in the ileum or colon

PURPOSE

The strength of the uninjured and anastomosed intestinal wall is determined by its submucosal connective tissue. Matrix degradation by matrix metalloproteinases may result in loss of strength. It is known that anastomotic construction leads to up-regulation of matrix metalloproteinase activity in the wound area, but no quantitative data are available as to the extent of this effect throughout the intestinal wall. This study was designed to quantitate changes in gelatinolytic activity in the intestine after anastomotic construction in the ileum or colon.

METHODS

An anastomosis was constructed in the distal ileum or distal colon of rats, and animals were killed after one or three days. Tissue samples (5 mm) were collected containing the suture line, its adjacent segments (2- x 5-mm in both directions) and at nine other, more distant, sites throughout the gastrointestinal tract. Similar samples were collected from nonoperated control rats. All samples were analyzed by quantitative gelatin zymography.

RESULTS

In control rats, the most prominent gelatinolytic activities were found at 80 kDa, thought to represent a nonspecific proteolytic activity, 60 kDa and 50 kDa, representing the proform and active form of matrix metalloproteinase-2, respectively. Activities were higher in the small bowel than in the large bowel. Anastomotic construction led to massive up-regulation of an activity at 105 kDa, and its dimer, believed to represent promatrix metalloproteinase-9. Matrix metalloproteinase-2 remained unaffected, whereas the activity of the 80 kDa protein was significantly (P < 0.05) reduced. Significantly increased matrix metalloproteinase-9 activity was found in the actual anastomotic segments and in the immediately adjacent tissue. Matrix metalloproteinase-9 activities in the anastomotic segments were highest at Day 1 in the ileum and at Day 3 in the colon. Anastomotic construction in the ileum or colon did not lead to any significant changes of any gelatinolytic activity at the more distant sites in the bowel wall.

CONCLUSIONS

Up-regulation of gelatinase activity after anastomotic construction in the intestine is caused by matrix metalloproteinase-9. Because the effect is local and not systemic, unwanted matrix degradation at distant sites seems unlikely.

No detrimental effects of repeated laparotomies on early healing of experimental intestinal anastomoses

BACKGROUND

Little is known about the impact of repeated laparotomies on intestinal anastomotic healing. While experimental data are completely lacking, the sparse data available from clinical studies report high anastomotic failure rates, suggesting a negative effect in this respect. Since the unequivocal determination of such an effect may have important consequences for choosing the optimal treatment strategy for patients suffering from intra-abdominal infection, an experimental study has been performed in an established rodent model.

METHODS

Intestinal anastomoses were constructed in healthy Wistar rats (ileal and colonic anastomoses) or 24 h after peritonitis was induced by caecal ligation and puncture (colonic anastomosis only). Rats were then scheduled to undergo no, one (after 24 h) or two relaparotomies (after 24 and 48 h). Anastomotic strength was assessed 3 and 5 days after anastomotic construction. On the third post-operative day anastomotic hydroxyproline levels, matrix metalloproteinase activity and myeloperoxidase activity were measured.

RESULTS

No negative impact of repeated laparotomies was measured on any of the parameters measured. Under non-infectious conditions even an improvement in breaking strength (+48%, p=0.017) but not bursting pressure was found after two relaparotomies, but only in the ileum on the third post-operative day.

CONCLUSIONS

In this experimental setting, early anastomotic healing is not adversely affected by repeated laparotomies.

Intrathoracic leaks following esophagectomy are no longer associated with increased mortality

OBJECTIVES

Assess outcomes following intrathoracic leaks after esophagectomy from 1970 to 2004 to evaluate the impact of evolving surgical and perioperative techniques on leak-associated mortality (LAM).

SUMMARY BACKGROUND DATA

An intrathoracic leak following esophagectomy has historically been considered a catastrophic event, with mortality as high as 71%. Concerns about this complication often affect choice of surgical approach for esophagectomy.

METHODS

A retrospective review of all esophagectomies for cancer from 1970 to 2004 (n = 1223) was performed. Outcomes following intrathoracic anastomoses (n = 621) were analyzed by era: historical 1970-1986 (n = 145) and modern 1987-2004 (n = 476).

RESULTS

There was no difference in the frequency of leak between the time intervals (4.8% versus 6.3%, P = 0.5). Despite a significant increase in the use of preoperative chemoradiation (1% versus 42%, P < 0.001) in the historical versus modern era, the overall mortality decreased from 11% to 2.5% (P < 0.001). The LAM was markedly reduced from 43% to 3.3% (P = 0.016). Factors associated with LAM included failure to use enteral nutrition (HR 13.22, CI 1.8-96.8) and era in which the surgery was performed (HR 18.3, 1.9-180). Other differences included an increased proportion of successful reoperations for leak control (11/30 versus 0/7, P = 0.08) and use of reinforcing muscle flaps (7/11). In the modern era, perioperative mortality is not significantly different for patients with or without intrathoracic leaks (3.3% versus 2.5%, P = 0.55), nor is long-term survival (P = 0.16).

CONCLUSIONS

Modern surgical management of intrathoracic leaks results in no increased mortality and has no impact on long-term survival. Clinical decisions regarding the use of intrathoracic anastomoses should not be affected by concerns of increased mortality from leak.

Complications following full-thickness small intestinal biopsy in 66 dogs: a retrospective study

OBJECTIVES

To retrospectively report the complications seen after full-thickness multiple small intestinal biopsies were performed in 66 dogs.

METHODS

Animals that died as a result of enteric wound breakdown were compared with the surviving population to identify fatal risk factors.

RESULTS

Seventeen dogs had hypoalbuminaemia and eight had albumin levels below 20 g/I at surgery. Twelve dogs had concurrent disease, of which seven had skin disease. Seven dogs suffered minor complications which resolved with treatment. Eight dogs (12 per cent) died or were euthanased between three and nine days postoperatively (mean [sd] 4.5 [2.1]) due to enteric wound breakdown. Seven of these dogs developed septic peritonitis and one died of haemorrhage. No statistically significant differences were identified in any of the parameters examined for the development of fatal enteric wound dehiscence.

CLINICAL SIGNIFICANCE

Full-thickness intestinal biopsy is not a benign procedure. However, this study concludes that there are no consistent predictors for patients at increased risk of enteric wound breakdown.

The effects of systemic hypoxia on colon anastomotic healing: an animal model

PURPOSE

Acute postoperative systemic hypoxia occurs frequently in the clinical setting following intestinal resection, as a result of complications such as pneumonia, pulmonary edema, or the acute respiratory distress syndrome. Although it is well established that oxygen is essential for metabolism in general and intestinal anastomotic healing, the mechanisms by which systemic hypoxia affect this process are not clear. The purpose of this study was to establish an animal model to simulate acute systemic hypoxia and to examine the effects on anastomotic healing. We investigated the hypothesis that systemic hypoxia impairs anastomotic healing in the colon by disrupting revascularization via changes in the expression of two putative angiogenic factors: inducible nitric oxide synthase and vascular endothelial growth factor.

METHODS

Phase I: Juvenile male Sprague-Dawley rats underwent carotid artery cannulation. In a controlled environment the FiO2 was incrementally decreased from 21 to 9 percent and the resultant PaO2 measured. Phase II: Animals underwent colonic transection with immediate reanastomosis and were placed in either a normoxic (FiO2 21 percent) or hypoxic (FiO2 11 percent) environment for seven days. Perianastomotic in vivo tissue oxygen saturation was measured before segmental colon resection in each of the animals and at seven days before measurement of anastomotic bursting pressure. Perianastomotic tissue samples were assessed by Western blot assay for the expression of vascular endothelial growth factor and inducible nitric oxide synthase protein. Sections from each tissue sample were taken and evaluated by a pathologist blinded to treatment group for determination of anastomotic healing score.

RESULTS

Phase I: Incrementally decreasing the FiO2 resulted in a progressive decrease in PaO2 (r2 = 0.77). Phase II: Animals maintained in a hypoxic environment had a significant decrease in tissue oxygen saturation (73 +/- 9 percent vs. 94 +/- 3 percent; P < 0.0001) and anastomotic bursting pressure (118 +/- 18 mmHg vs. 207 +/- 30 mmHg; P < 0.0001) compared with normoxic controls. Systemic hypoxia induced a significant increase, when compared with normoxic controls, in vascular endothelial growth factor (247.1 +/- 9.5 vs. 142.2 +/- 10.6; P < 0.0001) and inducible nitric oxide synthase (259.6 +/- 21.1 vs. 120.2 +/- 10.9; P < 0.0001) protein expression and led to a significant decrease in the overall wound-healing score.

CONCLUSION

This study validates a new animal model to study the effects of acute systemic hypoxia on colonic anastomotic healing. In this model, systemic hypoxia directly translated into local tissue hypoxia, and anastomotic healing was impaired. Contrary to our original hypothesis, hypoxia led to a significant increase in vascular endothelial growth factor and inducible nitric oxide synthase protein expression at the colonic anastomotic site. Impairment in anastomotic integrity despite upregulation of these angiogenic factors could be a result of the inability of wounded tissue to respond to vascular endothelial growth factor and inducible nitric oxide synthase or alternatively, hypoxia may adversely affect collagen synthesis and deposition directly.

[Leakages after surgery of the lower gastrointestinal tract]

The incidence of anastomotic leakage in colorectal surgery is 1% to 12%. Every deviation from the normal postoperative course must raise suspicion of a leak. Diagnosis is made radiologically by rectal enema or CT. Limited leakages without clinical signs can be treated conservatively by wait-and-see. Larger anastomotic failure with intra-abdominal abscesses or peritonitis requires reanastomosis in combination with a diverting loop ileostomy or colostomy. A Hartmann procedure with open abdominal management may be indicated in severely ill patients with feculent peritonitis. In the pelvis, even large leaks may heal spontaneously when stool passage is diminished by a proximal diverting enterostomy. There is no benefit of primary loop enterostomies concerning the incidence of anastomotic leaks; however, they reduce the number of operative revisions due to anastomotic failure. Therefore they are proposed in risk patients and intraoperatively difficult anastomoses.

[Anastomotic leaks in the upper gastrointestinal tract]

Anastomotic leaks are still among the most common severe postoperative complications and account for the majority of postoperative deaths after esophagectomy and gastrectomy. Every disturbance of the normal postoperative course should trigger surgeons to consider an underlying anastomotic leak and initiate a specific diagnostic workup. This includes direct endoscopic inspection of the anastomosis to evaluate the vitality of the anastomosed organs and the size of the leak. Adequate external drainage of the leak and prevention of further contamination are the primary therapeutic goals. Selection of therapy is guided by the available modalities for sufficiently draining the leak and avoiding sepsis. The spectrum of therapeutic options ranges from simple opening of the neck incision in cervical esophageal anastomoses, interventional placement of drains, to endoscopic intervention with closure of the fistula or placement of stents, and reoperation with exclusion, diversion, or discontinuity resection.

Surgery and angiogenesis

Surgery may be regarded as an angiogenesis-inducing condition since it evokes the release of many angiogenic factors. Regarding the mechanistic overlap between tumor-associated neovascularisation and (physiological) angiogenesis in response to injury and hypoxia, surgery may promote the uncontrolled growth of residual dormant tumor cells. With the advent of anti-angiogenic agents, surgeons will be faced with more patients undergoing surgery for primary and secondary tumors under anti-angiogenic treatment. This could present problems with regard to angiogenesis-dependent phenomena such as wound repair, healing of intestinal anastomoses and liver regeneration. In this review we will discuss these matters from a biomedical and clinical point of view.

Colo-rectal anastomotic leakage often masquerades as a cardiac complication

OBJECTIVE

The aim of this study was to identify the mode of presentation of patients with clinical anastomotic leaks following restorative colorectal resection for carcinoma.

PATIENTS AND METHODS

Prospective information was collected on all patients having restorative resection of colorectal cancer. These data were reviewed for a five-year period (1994-1998) to identify all patients who had suffered a clinical anastomotic leak and their notes were retrieved and reviewed.

RESULTS

Three hundred and seventy-nine patients underwent restorative resection for colorectal cancer during the study period (178 female, 201 male), mean age 70 years (range 36-94). There were 22 (6%) clinical anastomotic leaks. Seven (32%) patients presented with obvious abdominal peritonitis. The remaining 15 (68%) were initially misdiagnosed. Thirteen (59%) patients were treated for cardiac symptoms, 1 (5%) patient for obstruction and 1 (5%) for ascites. The delay in diagnosis ranged from 0 to 11 days (mean 4 days). For the whole series of 379 there were 30 patients who suffered cardiac symptoms (8%) 13(43%) of whom had an anastomotic leak.

CONCLUSION

Patients who develop cardiac symptoms following restorative colorectal resection for carcinoma should have a water soluble enema as there is a 40% chance that they will have an anastomotic leak.

Impaired healing of cutaneous wounds and colonic anastomoses in mice lacking thrombin-activatable fibrinolysis inhibitor

Plasmin and other components of the plasminogen activation system play an important role in tissue repair by regulating extracellular matrix remodeling, including fibrin degradation. Thrombin-activatable fibrinolysis inhibitor (TAFI) is a procarboxypeptidase that, after activation, can attenuate plasmin-mediated fibrin degradation by removing the C-terminal lysine residues from fibrin, which play a role in the binding and activation of plasminogen. To test the hypothesis that TAFI is an important determinant in the control of tissue repair, we investigated the effect of TAFI deficiency on the healing of cutaneous wounds and colonic anastomoses. Histological examination revealed inappropriate organization of skin wound closure in the TAFI knockout mice, including an altered pattern of epithelial migration. The time required to completely heal the cutaneous wounds was slightly delayed in TAFI-deficient mice. Healing of colonic anastomoses was also impaired, as reflected by decreased strength of the tissue at the site of the suture, and by bleeding complications in 3 of 14 animals. Together, these abnormalities resulted in increased mortality in TAFI-deficient mice after colonic anastomoses. Although our study shows that tissue repair, including re-epithelialization and scar formation, occurs in TAFI-deficient mice, TAFI appears to be important for appropriate organization of the healing process.

Colonic anastomotic strength and matrix metalloproteinase activity in an experimental model of bacterial peritonitis

BACKGROUND

Clinical studies report conflicting results on the safety of primary intestinal anastomoses in the presence of peritonitis, and comprehensive experimental data are lacking. The present study investigated whether the strength of experimental colonic anastomoses is affected if surgery is performed in the presence of pre-existing bacterial peritonitis.

METHODS

Colonic anastomoses were constructed in Wistar rats 24 h after caecal ligation and puncture or a sham procedure. Anastomotic strength was assessed by measuring breaking strength and bursting pressure during the first 5 days after operation. Anastomotic hydroxyproline levels were measured and matrix metalloproteinase (MMP) activity was analysed by quantitative gelatin zymography.

RESULTS

Anastomotic strength was lowered in the presence of bacterial peritonitis but in a minor and transient way. The breaking strength was lower only immediately after construction of the anastomosis (- 15 per cent, P = 0.011) and the bursting pressure only on the third postoperative day (- 33 per cent, P = 0.038); no anastomotic dehiscence was observed. At 3 days after operation increased levels of MMP activity were observed but anastomotic hydroxyproline content was not affected by bacterial peritonitis.

CONCLUSION

The influence of bacterial peritonitis on the development of anastomotic strength is limited. This experimental finding lends support to recent clinical studies that have demonstrated the feasibility of constructing a primary anastomosis under these conditions.

Risk factors for leakage following intestinal anastomosis in dogs and cats: 115 cases (1991-2000)

OBJECTIVE

To identify factors associated with leakage following intestinal anastomosis in dogs and cats.

DESIGN

Retrospective study.

ANIMALS

90 dogs and 25 cats.

PROCEDURE

Medical records of all dogs and cats that underwent intestinal resection and anastomosis between 1991 and 2000 were reviewed, and information on 27 factors was recorded.

RESULTS

Anastomotic leakage was identified in 13 of the 90 dogs but in none of the 25 cats. Preoperative factors significantly associated with development of anastomotic leakage in dogs included preoperative peritonitis, serum albumin concentration, a left shift, and indication for surgery (dogs with intestinal foreign bodies were more likely to have leakage than dogs that underwent surgery for any other cause). Postoperative and case management factors significantly associated with development of leakage included duration of hospitalization, supplemental alimentation, whether the dog ate the day after surgery, blood product administration, and outcome (died vs survived). Discriminant analysis was performed, and dogs with 2 or more of the following factors were predicted to develop anastomotic leakage: preoperative peritonitis, intestinal foreign body, and serum albumin concentration < or = 2.5 g/dL. The model accurately predicted whether leakage would develop in 67 of 80 (84%) dogs.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggest that a variety of factors may be associated with development of intestinal anastomotic leakage in dogs. In particular, dogs with 2 or more of the following risk factors are predicted to be at high risk for developing anastomotic leakage: preoperative peritonitis, intestinal foreign body, and serum albumin concentration < or = 2.5 g/dL.

Adverse effects of the antiangiogenic agent angiostatin on the healing of experimental colonic anastomoses

BACKGROUND

Antiangiogenic cancer therapy is likely to be administered long term for sustained suppression of tumor outgrowth. Surgeons will encounter more patients undergoing such therapy. Therefore, it is essential to know the effects of antiangiogenic agents on physiological angiogenesis, as occurs during the healing of colonic anastomoses.

METHODS

Angiostatin was generated from human plasma and administered continuously. In 38 mice, the right colon was anastomosed after transection: group 1 (n = 13), anastomotic healing under angiostatin treatment from surgery until death (day 7); group 2 (n = 13), phosphate-buffered saline controls. For healing on discontinuation of treatment, group 3 (n = 6) received angiostatin treatment preceding surgery during 4 days; group 4 (n = 6) included controls. On day 7, all mice were inspected for signs of anastomotic leakage. Bursting pressure measurements were performed to test anastomotic strength. Neovascularization was assessed semiquantitatively by immunohistochemistry.

RESULTS

Mice treated with angiostatin postoperatively showed significantly more signs of leakage, more adhesions, and peritonitis. One mouse died on day 5. Five mice had paralytical ileus. The bursting pressure in group 1 was 135 +/- 20 mm Hg, versus 175 +/- 12 mm Hg in group 2 (mean +/- SEM). Significantly fewer new vessels were found surrounding the anastomosis in the treated group (6.6 +/-.9) versus controls (16 +/- 1.6). All controls, as well as those animals treated with angiostatin only until surgery (group 3), displayed normal healing and showed no signs of peritonitis or ileus.

CONCLUSIONS

Angiostatin impairs anastomotic healing in mice. However, on discontinuation of antiangiogenic therapy, normal anastomotic healing is promptly restored.

Randomized clinical trials in colon cancer

Prospective randomized trials involving the surgical and chemotherapeutic treatment of resectable colon cancer are reviewed. Emphasis is placed on those trials that have impacted the current management of primary colon cancer.

Single-layer continuous versus two-layer interrupted intestinal anastomosis: a prospective randomized trial

OBJECTIVE

To determine the suitability of a single-layer continuous technique for intestinal anastomosis in a surgical training program.

SUMMARY BACKGROUND DATA

Several recent reports have advocated the use of a continuous single-layer technique for intestinal anastomosis. Purported advantages include shorter time for construction, lower cost, and perhaps a lower rate of anastomotic leakage. The authors hypothesized that the single-layer continuous anastomosis could be safely introduced into a surgical training program and that it could be performed in less time and at a lower cost than the two-layer interrupted anastomosis.

METHODS

The study was conducted during a 3-year period ending September 1999. All adult patients requiring intestinal anastomosis were considered eligible. Patients who required anastomosis to the stomach, duodenum, and rectum were excluded. Patients were also excluded if the surgeon did not believe either technique could be used. Patients were randomly assigned to one- or two-layer techniques. Single-layer anastomoses were performed with a continuous 3-0 polypropylene suture. Two-layer anastomoses were constructed using interrupted 3-0 silk Lembert sutures for the outer layer and a continuous 3-0 polyglycolic acid suture for the inner layer. The time for anastomosis began with the placement of the first stitch and ended when the last stitch was cut. Anastomotic leak was defined as radiographic demonstration of a fistula or nonabsorbable material draining from a wound after oral administration, or visible disruption of the suture line during reexploration.

RESULTS

Sixty-five single-layer and 67 two-layer anastomoses were performed. The groups were evenly matched according to age, sex, diagnosis, and location of the anastomosis. Two leaks (3.1%) occurred in the single-layer group and one (1.5%) in the two-layer group. Two abscesses (3.0%) occurred in each group. A mean of 20.8 minutes was required to construct a single-layer anastomosis versus 30.7 minutes for the two-layer technique. Mean length of stay was 7.9 days for single-layer patients and 9.9 days for two-layer patients; this difference did not quite reach statistical significance. Cost of materials was $4.61 for the single-layer technique and $35.38 for the two-layer method.

CONCLUSIONS

A single-layer continuous anastomosis can be constructed in significantly less time and with a similar rate of complications compared with the two-layer technique. It also costs less than any other method and can be incorporated into a surgical training program without a significant increase in complications.