Evaluation of anastomotic microcirculation after low anterior rectal resection: an experimental study with different reconstruction forms in dogs

Vascular anatomy of the small intestine-a comparative anatomic study on humans and pigs

BACKGROUND

Porcine models are well established for studying intestinal anastomotic healing. In this study, we aimed to clarify the anatomic differences between human and porcine small intestines. Additionally, we investigated the influences of longitudinal and circular sutures on human small intestine perfusion.

METHODS

Intestines were obtained from human cadavers (n = 8; small intestine, n = 51) and from pigs (n = 10; small intestine, n = 60). Vascularization was visualized with mennige gelatin perfusion and high-resolution mammography. Endothelial cell density was analyzed with immunohistochemistry and factor VIII antibodies. We also investigated the influence of suture techniques (circular anastomoses, n = 19; longitudinal sutures, n = 15) on vascular perfusion.

RESULTS

Only human samples showed branching of mesenteric vessels. Compared to the pig, human vessels showed closer connections at the entrance to the bowel wall (p = 0.045) and higher numbers of intramural anastomoses (p < 0.001). Porcine main vessels formed in multifilament-like vessel bundles and displayed few intramural vessel anastomoses. Circular anastomoses induced a circular perfusion defect at the bowel wall; longitudinal anastomoses induced significantly smaller perfusion defects (p < 0.001). Both species showed higher vascular density in the jejunum than in the ileum (p < 0.001). Human samples showed similar vascular density within the jejunum (p = 0.583) and higher density in the ileum (p < 0.001) compared to pig samples.

CONCLUSION

The results showed significant differences between human and porcine intestines. The porcine model remains the standard for studies on anastomotic healing because it is currently the only viable model for studying anastomosis and wound healing. Nevertheless, scientific interpretations must consider the anatomic differences between humans and porcine intestines.

Clinical manifestations and risk factors of anastomotic leakage after low anterior resection for rectal cancer

BACKGROUND

Anastomotic leakage is a common complication that can be associated with catastrophic consequences. However, the risk factors and incidence of anastomotic leakage vary considerably among clinical studies because of the lack of a standardized definition, clinical course and appropriate treatment options. The aim of this study was to identify and classify the clinical manifestations and treatment of anastomotic leakage and analyse the possible risk factors after low anterior resection.

METHODS

From January 2009 to June 2010, 632 patients underwent low anterior resection for primary colorectal cancer at Samsung Medical Center. Patients with only one colorectal anastomosis were included from this prospectively collected medical database.

RESULTS

The overall leakage rate was 6.0% (n = 38). In cases of generalized leakage, the patients that selected surgical management, regardless of having protective enterostomy and time of occurrence, had better outcomes. Protective enterostomy did not have a preventive effect and was not associated with a lower rate of anastomotic leakage. However, protective enterostomy confined the inflammation to only the pelvic cavity (P = 0.045) and no surgical intervention was initially needed. Male gender (P = 0.021, relative risk (RR) = 2.680, 95% confidence interval (CI) = 1.164-6.171) and side-to-end/J pouch-to-end anastomosis (P = 0.012, RR = 2.696, 95% CI = 1.249-5.818) were significant risk factors that affected anastomotic leakage.

CONCLUSION

Surgical management is the best choice for generalized leakage. A protective enterostomy diminished the occurrence of generalized leakage and consequent surgical management; therefore, fragile patients at high risk for anastomotic leakage are recommended to undergo protective enterostomy.

Comparison of intestinal microcirculation and wound healing in a rat model

PURPOSE

If a colonic or small bowel lesion is not accessible for endoscopic mucosal resection, enterotomy is a possible although rarely performed surgical technique. It has never been compared to circular anastomosis regarding leakage rate, bowel wall perfusion, and wound healing. Thus, the aim of this basic experimental scientific study was to investigate perianastomotic microcirculation and wound healing.

METHODS

Forty rats were divided into four groups (1 jejunal anastomosis, 2 jejunal enterotomy, 3 colonic anastomosis, and 4 colonic enterotomy). Following anastomosis and enterotomy, the intestinal perfusion was measured using laser fluorescence angiography (IC-View). On postoperative day 7, the surface of the mucosal villi, expression of matrix metalloproteinases (MMP) 2, 8, 9, and 13, and the number of proliferating cells (Ki67) as well as the collagen types I/III ratio were analyzed.

RESULTS

The perianastomotic microperfusion was significantly reduced in all groups compared to the reference region. The perianastomotic perfusion index was significantly reduced in group 1 compared with group 2, whereas the perfusion index in group 3 was slightly but not significantly reduced in comparison to group 4. Ki67 was elevated in both circular anastomosis groups. Surface of the mucosal villi, MMP expression, and collagen type I/III ratio revealed no significant differences.

CONCLUSIONS

Our study affirms the theoretical consideration of a better microperfusion of the bowel wall following an antimesenterial enterotomy and demonstrates that enterotomy is not inferior compared to circular anastomosis. Even though enterotomy is a rarely used surgical technique, it should be regarded as a possible alternative in particular situations.

Application of the HyperEye Medical System for esophageal cancer surgery: a preliminary report

The HyperEye Medical System is a newly developed device that allows for the visualization of the fluorescent image of indocyanine green enhanced by near-infrared light among the surrounding vivid color images. We recently applied this system to confirm the blood flow of an esophageal substitute, and for sentinel node navigation during esophagectomy. Five consecutive patients with thoracic esophageal cancer who underwent a subtotal esophagectomy between June 2010 and May 2011 were enrolled in the study. The esophageal substitute used for reconstruction was the stomach and ileocecum in four and one cases, respectively. In all cases with a reconstructive stomach, fine arterial blood flow and venous perfusion were observed. The blood flow of the reconstructive colon was poor before microvascular anastomosis, however, it dramatically increased after anastomosis. Concerning the sentinel node navigation, the fluorescence of lymph nodes, lymphatic vessels, and the tumor site were detected. The postoperative courses of all cases were uneventful, with no mortalities or anastomotic leakage occurring.

How to assess intestinal viability during surgery: A review of techniques

Objective and quantitative intraoperative methods of bowel viability assessment are essential in gastrointestinal surgery. Exact determination of the borderline of the viable bowel with the help of an objective test could result in a decrease of postoperative ischemic complications. An accurate, reproducible and cost effective method is desirable in every operating theater dealing with abdominal operations. Numerous techniques assessing various parameters of intestinal viability are described by the studies. However, there is no consensus about their clinical use. To evaluate the available methods, a systematic search of the English literature was performed. Virtues and drawbacks of the techniques and possibilities of clinical application are reviewed. Valuable parameters related to postoperative intestinal anastomotic or stoma complications are analyzed. Important issues in the measurement and interpretation of bowel viability are discussed. To date, only a few methods are applicable in surgical practice. Further studies are needed to determine the limiting values of intestinal tissue oxygenation and flow indicative of ischemic complications and to standardize the methods.

Biosutures improve healing of experimental weak colonic anastomoses

PURPOSE

Use of biosutures in animal models of colonic anastomoses is associated with decreased adhesions without affecting anastomotic strength. This study aimed to evaluate the effect of biosutures on colonic anastomoses kept free of adhesions by peritoneal instillation of icodextrin 4%.

METHODS

Three types of colonic anastomoses were compared: group 1, anastomoses without icodextrin 4% and control suture; group 2, anastomoses with icodextrin 4% (adhesion-free anastomoses) and control suture; and group 3, anastomoses with icodextrin 4% (adhesion-free anastomoses) and biosutures. Dehiscence, adhesion formation, and anastomotic strength were evaluated on day 4 after the operation.

RESULTS

When peritoneal icodextrin 4% was used in anastomoses with conventional sutures, a decrease in the adhesion index (P = 0.01) and a lower bursting pressure (P = 0.15) were observed. When adhesion-free anastomoses were compared, those performed with biosutures had a higher bursting pressure (P = 0.008) and a similar pattern of adhesion index (P = 0.48).

CONCLUSIONS

Biosutures improve the strength of adhesion-free colonic anastomoses.

Intraoperative assessment of kidney allograft perfusion by laser-assisted indocyanine green fluorescence videography

BACKGROUND

Kidney allograft function crucially depends on the quality of organ perfusion. Duplex sonography, however, frequently reveals hypoperfused segments that remained undetectable to visual inspection intraoperatively. To date, no imaging system supplementing the surgeon's experience has achieved clinical acceptance. The present work examines whether laser-assisted indocyanine green (ICG) fluorescence-videography can be used as a safe and sensitive technique for the intraoperative assessment of renal allograft perfusion.

METHODS

Intraoperative assessment of organ perfusion by laser-assisted ICG fluorescence videography (IC-VIEW) was performed in 10 consecutive de novo renal transplantations. The IC-VIEW system allows the visualization of graft perfusion by the fluorescein dye ICG that emits infrared light after exposure to laser light.

RESULTS

Perfusion measurements were successful in all 10 transplant recipients. Fluorescence videography produced brilliant, sharply contrasted images of the organs, allowing the detection of even small perfusion deficits. Remarkably, this technique detected 1 large perfusion defect that had remained imperceptible to visual inspection. Repositioning of the graft led to a homogeneous overall perfusion. There were no complications with the ICG injection or the imaging device.

CONCLUSION

Laser-assisted ICG fluorescence videography is a feasible and safe technique for the intraoperative assessment of renal allograft perfusion.

Intraoperative laser fluorescence angiography in colorectal surgery: a noninvasive analysis to reduce the rate of anastomotic leakage

PURPOSE

Up to 19% of all colorectal resections develop clinically apparent insufficiencies. Insufficient perfusion of the anastomosis is recognized as an important risk factor. As tissue perfusion can be objectified intraoperatively using laser fluorescence angiography (LFA), its effect on the rate of anastomotic complications was evaluated in a retrospective matched-pairs analysis.

METHODS

Between 2003 and 2008, all anastomosis or resection margins in colorectal cancer resections were investigated intraoperatively using LFA (LFA group). Patients with colorectal cancer resections between 1998 and 2003 without LFA served as the control group. Four hundred two patients were matched for age, T-stage, type of resection and anastomosis, defunctioning stoma, administration of blood, emergency conditions, and body mass index. Statistical analysis was performed using the Fisher and the Wilcoxon tests.

RESULTS

Twenty-two surgical revisions were necessary due to anastomotic leakage, seven (3.5%) in the LFA group and 15 (7.5%) in the control group. Subgroup analysis revealed that in elective resections the rate of revision was 3.1% (LFA group) and 7.7% (control group) (p = 0.04, risk of revision (ROR) reduced by 60%). In patients older than 70 years, the rate of revision was 4.3% (LFA group) compared to 11.9% (control group) (p = 0.04, ROR reduced by 64%). After hand-sewn anastomosis, the rate of revision was 1.2% (LFA group) and 8.5% (control group) (p = 0.03, ROR reduced by 84%). Hospital stay was significantly reduced in the LFA group (Wilcoxon test; p = 0.01).

CONCLUSION

There was an overall reduction in the absolute revision rate of 4% in the LFA group and a significantly reduced rate of revision in the subgroup analysis of patients undergoing elective colorectal resections, in patients older than 70 years and in patients with hand-sewn anastomosis. This demonstrates that LFA is a method that may significantly reduce not only the rate of severe complications in colorectal surgery but also the hospital length of stay.