Effects of amniotic membrane on the healing of primary colonic anastomoses in the cecal ligation and puncture model of secondary peritonitis in rats

Purpose  We aimed to investigate the effects of amniotic membrane on primary colonic anastomoses in a rat peritonitis model. Materials and methods  Fifty female Sprague Dawley rats were used in the study. Bacterial peritonitis was induced in all rats by performing a cecal ligation and puncture. Ten rats served as controls for the bursting pressure measurement, while the other 40 animals were divided into two groups (the anastomosis group (P) or the amniotic membrane group (PA)), and all of them underwent colonic anastomosis. The latter group had amniotic membrane covering their anastomoses. Half of the PA and P groups were sacrificed on the third postoperative day (PA3, P3), and the other half on the seventh postoperative day (PA7, P7). Results  The bursting pressures were significantly higher in groups PA3 and PA7 compared with P3 (p < 0.01) and P7 (p < 0.05), respectively. Inflammatory cell infiltration and adhesion scores were significantly lower in groups PA3 and PA7 compared with groups P3 (p < 0.001, p < 0.01, respectively) and P7 (p < 0.001, p < 0.05, respectively). Neoangiogenesis, fibroblast activity, collagen deposition, and hydroxyproline concentrations were significantly higher in groups with amniotic membrane than in groups without amniotic membrane (p < 0.05, for all comparisons). Conclusion  This study showed that the covering of colonic anastomoses with amniotic membrane significantly prevented the delaying effect of intraperitoneal sepsis and provided a safer and stronger anastomosis than suture and that this was the case for both the early and late phases of anastomotic healing in the colon.     

The Effect of Octreotide on Healing of Injured Colonic Anastomosis with Immediate Postoperative Intraperitoneal Administration of 5-Fluorouracil

Purpose This study was designed to investigate the effect of octreotide on side effects of immediate usage of 5-fluorouracil after colonic anastomosis. Methods Forty male Wistar rats were randomly assigned into four groups and underwent standardized left colonic anastomosis. The rats served as control or received intraperitoneal 5-fluorouracil (20 mg/kg daily), subcutaneous octreotide (20 μg/kg daily), or both. Diarrhea and wound complications were noted during the experiment. The colonic anastomoses were assessed for healing on postoperative Day 7 by determining the anastomotic bursting pressure, performing histologic examination, and measuring the tissue hydroxyproline content, serum malondialdehyde, and nitric oxide levels. Intraperitoneal adhesions and anastomotic leakage were also noted. Results No statistical significant difference was found between the control and octreotide groups for each of the parameters measured. Immediate 5-fluorouracil use resulted with higher adhesion score (P = 0.002), significant depression in anastomotic bursting pressure (P = 0.0001), histopathologic score (P = 0.0001), hydroxyproline content (P = 0.0001), and increasing nitric oxide (P = 0.0001) and malondialdehyde levels (P = 0.0001) compared with the control group. Diarrhea was seen in 80 percent of the 5-fluorouracil group but in neither the control nor octreotide groups (P = 0.0001 for each comparison). However, all these parameters were ameliorated by use of concomitant octreotide and 5-fluorouracil (P = 0.019, P = 0.023, P = 0.0001, P = 0.006, P = 0.0001, and P = 0.013, respectively). In addition, diarrhea was found to be prevented (P = 0.0001). Conclusions The results of this study showed that concomitant octreotide use might prevent the side effects of 5-fluorouracil, such as diarrhea, postoperative adhesion, and delaying the anastomotic healing parameters. In addition, it might reduce tissue damage and inflammation.     

Effects of amniotic membrane on the healing of normal and high-risk colonic anastomoses in rats

Bacground  This study was aimed at examining whether or not the addition of amniotic membrane to a sutured colonic anastomosis improves its healing. Material and methods  Ninety female Sprague Dawley rats were used in the study. Ten served as controls for bursting pressure measurement, while the other 80 animals were divided into four groups: Anastomosis group (NA), high-risk anastomosis group (HRA), anastomosis plus amniotic membrane group (NA-AM), and high-risk anastomosis plus amniotic membrane group (HRA-AM). The last two groups had amniotic membrane covering their anastomoses. Anastomotic evaluation was carried out on the third (NA3, HRA3, NA-AM3, and HRA-AM3, respectively) and seventh (NA7, HRA7, NA-AM7, and HRA-AM7, respectively) postoperative days. The main outcome measures were gross anastomotic healing, adhesion formation, mechanical strength, hydroxyproine content, and parameters of histopathological healing. Results  Anastomotic dehiscence rate was 66.7%, 40%, 20%, and 10% in group HRA7, HRA3, NA7, and NA3, respectively. However, there was no significant difference between groups regarding the dehiscence rate. The adhesion scores were significantly higher in groups NA3 and HRA3 compared with groups NA-AM3 and HRA-AM3, respectively (p < 0.05, p < 0.001). Bursting pressure was significantly higher in groups with amniotic membrane compared without amniotic membrane (p < 0.05, for all comparison). Inflammatory cell infiltration was significantly lower in groups with amniotic membrane compared with groups without amniotic membrane (p < 0.05, for all both comparisons). Neoangiogenesis was significantly higher in the NA-AM3 and HRA-AM3 groups compared with the NA3 (p < 0.01) and HRA3 (p < 0.05) groups, respectively. Fibroblast activity was significantly higher in groups NA-AM3 and NA-AM7 compared with groups NA3 (p < 0.05) and NA7 (p < 0.05), respectively. Collagen deposition and hydroxyproline concentrations were significantly higher in groups with amniotic membrane compared with groups without amniotic membrane (p < 0.05, for all both comparisons). Conclusion  The covering of both normal and high-risk colonic anastomoses with amniotic membrane provides a beneficial effect over conventional suturing of healing. This study was presented as an oral presentation in the 18th World Congress of the International Association of Surgeons, Gastroenterologists, and Oncologists.     

Ischemic preconditioning improves stability of intestinal anastomoses in rats

Background  The aim of our study was to establish whether ischemic preconditioning (IPC) directly before performing a small bowel anastomosis has an effect on anastomotic stability and healing. Material and methods  Forty male Wistar rats were randomized to five groups: control (CO, n = 8) with preparation of the superior mesenteric artery (SMA) but without IPC. IPC groups had different intervals of ischemia (occlusion of the SMA) and reperfusion: 10 min ischemia and 20 min reperfusion (IPC10/20, n = 7), 10 min ischemia and 30 min reperfusion (IPC10/30, n = 8), 15 min ischemia and 20 min reperfusion (IPC15/20, n = 8), and 15 min ischemia and 30 min reperfusion (IPC15/30, n = 9). On the fourth postoperative day, the animals were relaparotomized: bursting pressure, hydroxyproline concentration, and histological ischemia mucosal injury scale of the anastomosis were assessed. Results  Four days after operation, the mean bursting pressure was 73 ± 6 mmHg in the control group, whereas it was significantly higher in IPC10/20 (113 ± 11 mmHg; p = 0.018), IPC10/30 (110 ± 13 mmHg; p = 0.001), and IPC15/30 (124 ± 9 mmHg; p = 0.003). IPC15/20 did not show a significant difference (63 ± 2 mmHg; p = 0.4). We did not find a significant effect regarding hydroxyproline concentration, but IPC diminished mucosal injury. Conclusions  IPC directly before performing a small bowel anastomosis has a time-dependent beneficial effect on anastomotic stability, thus indicating a new clinical approach to improve the healing process of intestinal anastomosis.     

Small intestinal submucosa for reinforcement of colonic anastomosis

Background  Different materials have been evaluated for anastomotic reinforcement to prevent gastrointestinal anastomotic leakage. In this experimental study, small intestinal submucosa (SIS) was tested as a sealing for stapled colonic anastomosis in a porcine model. The aims of this study were to determine the macroscopic and microscopic outcomes and to evaluate the safety and feasibility of applying SIS for anastomotic sealing. Materials and methods  Circular stapled anastomoses were performed in 18 pigs. Standard anastomosis in the control group (n = 8) was compared to an SIS-sealed anastomosis in the study group (n = 10). After 30 days, anastomotic segments were examined for macroscopic and microscopic regeneration and their resistance to mechanical stress. Furthermore, animal survival and clinical course were evaluated. Results  None of the animals developed anastomotic leakage, intraabdominal abscess, or peritonitis. Shrinkage of SIS was evident in nine of ten animals. Encapsulation and displacement of the SIS patches were seen in two animals. Quantity of anastomotic granulation tissue and rate of complete mucosal coverage of anastomotic line were increased in SIS-sealed anastomoses without reaching significance. Moreover, no significant differences were found in the rate of survival of the animals, anastomotic stricture formation, intraabdominal adhesions, anastomotic bursting pressure, and microscopic healing parameters of the anastomosis between stapled colonic standard anastomosis and anastomosis protected by SIS. Conclusion  The results of this study indicate a safe use of SIS for anastomotic reinforcement in a porcine model. Adverse effects like strictures, increased adhesions, and anastomotic abscesses were absent. Promoting effects on colonic wound healing by SIS were microscopically evident. The results argue for a careful clinical evaluation in humans.     

Effect of Iloprost on Impaired Anastomotic Healing Caused by 5-Fluorouracil plus Leucovorin

Purpose This experimental study was designed to investigate whether iloprost can reverse impaired colonic healing caused by immediate postoperative intraperitoneal administration of 5-fluorouracil plus leucovorin. Methods Eighty Wistar rats were randomized into four groups. After resection of a 1-cm segment of transverse colon, an end-to-end sutured anastomosis was generated. Rats received saline solution (Group 1), 5-fluorouracil plus leucovorin (Group 2), iloprost (Group 3), and 5-fluorouracil plus leucovorin plus iloprost (Group 4) intraperitoneally from the day of operation and once daily until killing. Each group was further randomized into two subgroups. Subjects were killed on the fifth (Subgroup a) and eighth (Subgroup b) postoperative days. After killing, anastomoses were examined macroscopically and graded histologically. Rats were measured for anastomotic bursting pressures and tissue hydroxyproline levels. Results The leakage rate of the anastomoses was significantly higher in the 5-fluorouracil plus leucovorin group compared with the other groups (P = 0.049). Bursting pressure was significantly lower in 2a subgroup (5-fluorouracil plus leucovorin, postoperative Day 5) than in 4a (5-fluorouracil plus leucovorin plus iloprost, postoperative Day 5; P < 0.001). Adhesion formation was significantly higher in all b subgroups compared with the Control b subgroup. Neoangiogenesis was significantly higher in iloprost and iloprost plus 5-fluorouracil plus leucovorin subgroups compared with the 5-fluorouracil plus leucovorin subgroups. Hydroxyproline levels, collagen deposition, fibroblasts, and white cell count were significantly higher in the iloprost plus 5-fluorouracil plus leucovorin b subgroup (postoperative Day 8) compared with the 5-fluorouracil plus leucovorin b subgroup (postoperative Day 8). Conclusions The immediate postoperative, intraperitoneal administration of iloprost counteracts and reverses the negative effects of 5-fluorouracil plus leucovorin chemotherapy and protects colonic healing in rats. The authors declare that they have no conflict of interest with the manufacturer of iloprost (ILOMEDIN?, Schering Berlin, Germany).     

Preoperative irradiation with 5 × 5 Gy in a murine isolated colon loop model does not cause anastomotic weakening after colon resection

Introduction  There are conflicting studies on the influence of fractionated preoperative 5 days of 5 Gy irradiation on tissue oxygenation and subsequent colonic anastomotic strength. To elucidate the effect of preoperative irradiation on anastomotic strength, an isolated colon loop model was developed. Methods  Male Wistar rats (n = 164) were randomly divided into three groups. One group remained untreated (control). In the other two groups, a loop of descending colon was exteriorized to create a hernia of the abdominal wall. After 4 weeks’ recovery, this loop was locally irradiated with 5 × 5 Gy of γ-rays or sham irradiated. One week after (sham-) irradiation, an anastomosis was performed in all groups. Tissue oxygenation (StO₂) was determined with visible light spectroscopy. The animals were sacrificed 3 or 7 days after the operation and the anastomosis was tested for bursting pressure and breaking strength. Results  Irradiated rats showed significantly more weight loss (90% SD 4.3 of initial body weight vs. 96% SD 2.8, p ≤ 0.05) and enteritis (18% vs. 5%, p = 0.013) compared to sham and control animals. StO₂ was not influenced by irradiation and was not predictive for anastomotic strength. The control group showed significantly lower bursting pressure and breaking strength compared to (sham-) irradiated animals. Conclusion  We developed a new isolated loop model for intermittent irradiation of the colon. Preoperative irradiation of the distal part of a colon anastomosis was successfully administered with acceptable side effects and did not cause reduced tissue oxygenation nor clinical signs of anastomotic weakening, nor objective reduction in bursting pressure and breaking strength. Financial support: Nijbakker Morra Foundation, Leiden; J.C. de Cock Foundation, Groningen.     

Hyperthermic intraperitoneal chemoperfusion (HIPEC) decrease wound strength of colonic anastomosis in a rat model

Background and aims There is controversy about the effect of the influence of hyperthermia and chemotherapeutic agents on the healing of intestinal anastomosis. The effects of hyperthermic intraperitoneal chemoperfusion (HIPEC) of wound healing after colonic anastomosis were investigated in a rat model. Materials and methods Thirty-six Wag/Rija rats were randomized into three groups of 12 animals each: group I: control (only colonic anastomosis was performed) (n = 12); group II: HIPEC (mitomycin C in a concentration of 20 mg/m² (n = 12) colonic anastomosis was performed before HIPEC; group III: HIPEC (mitomycin C in a concentration of 20 mg/m² (n = 12) colonic anastomosis was performed after HIPEC. Bursting pressure and bursting sites were recorded 4 and 10 days after intervention. Collagen deposits, inflammation and foreign body reactions were evaluated. Results Lower bursting pressure and lost of collagen were found in both HIPEC groups and compared with the control group. There was almost no difference between both HIPEC groups. They were noted overwhelmingly at the anastomosis in the HIPEC group. The degree of collagen accumulation was well-correlated with bursting pressure. Conclusion These results have shown that hyperthermic intraperitoneal chemoperfusion (HIPEC) impairs wound healing in colonic anastomosis in rats.     

Effect of fibrin glue on irradiated colonic anastomoses

INTRODUCTION: The present study was planned to research the effects of fibrin glue on irradiated colonic anastomoses. METHOD: The effect of fibrin glue on irradiated colonic anastomoses was investigated in four identical groups of rats. In Group I (control group) colonic anastomoses were performed without radiotherapy; in Group II, colonic anastomoses were performed five days after radiotherapy; in Group III, fibrin glue was applied to anastomotic line without radiotherapy; in Group IV, fibrin glue was applied to anastomotic line with radiotherapy. The healing of left colonic anastomoses was evaluated through the bursting pressure of the anastomotic segment and the hydroxyproline contents of the anastomosis. RESULTS: Measurements done on the fourth postoperative day revealed that anastomotic healing was impaired in rats that underwent radiotherapy ( P <0.001); fibrin glue had no effect on anastomotic healing in groups with or without radiotherapy. CONCLUSION: In the early phases of anastomotic healing, fibrin glue cannot help remove unwanted effects of preoperative radiotherapy.     

The healing of colon anastomosis covered with fibrin glue after early postoperative intraperitoneal chemotherapy

Background After colon resection for colonic cancer, the administration of antineoplastic agents may prolong survival by killing residual cancer calls and preventing metastasis, but may also slow anastomotic healing. This study was designed to determine the effects of 5-fluorouracil (5-FU) and leucovorin (LEV), injected intraperitoneally, on the healing of colonic anastomoses with or without fibrin glue (FG) covering. Methods Sixty rats were randomized to one of four groups. After resection of a transverse colon segment, an end-to-end sutured anastomosis was performed. Rats in the 5-FU+LEV and the 5- FU+LEV+FG groups received 5-FU+LEV intraperitoneally. The colonic anastomoses of the rats in the FG group and in the 5-FU+LEV+FG group were covered with fibrin glue. All rats were killed on postoperative day 8. Bursting pressure measurements were recorded and the anastomoses were examined macroscopically and histologically. Results The leakage rate of the anastomoses was significantly different among groups. Specifically, the leakage rate was significantly higher in the 5-FU+LEV group (40%) than in the FG and in the 5-FU+LEV+FG groups where there were no leakages (p=0.017). The mean adhesion formation score was significantly higher in rats of the 5-FU+LEV group, compared to the control (p=0.023), the FG (p=0.006) and the 5-FU+LEV+FG (p=0.006) groups. Bursting pressures were significantly lower in the 5-FU+LEV group than in the other groups (p<0.001). Also, bursting pressures were significantly lower in the control group compared to the FG and 5-FU+LEV+FG groups (p<0.001). Rats in the 5-FU+LEV+FG group had significantly greater neoangiogenesis and fibroblast activity than those in the 5-FU+LEV group (p=0.025). Conclusion The early intraperitoneal postoperative administration of 5-fluorouracil plus leucovorin impaired colonic wound healing. However, the application of fibrin glue prevented the deleterious effect of chemotherapy.     

Incidence,consequences, and risk factors for anastomotic dehiscence after colorectal surgery: a prospective monocentric study

Background Anastomotic dehiscence is the most severe surgical complication after large bowel resection. This study was designed to assess the incidence, to observe the consequences, and to identify the risk factors associated with anastomotic leakage after colorectal surgery. Materials and methods All procedures involving anastomoses of the colon or the rectum, which were performed between November 2002 and February 2006 in a single institution, were prospectively entered into a computerized database. Results One thousand eighteen colorectal resections and 811 anastomoses were performed over this 40-month period. The most frequent procedures were sigmoid (276) and right colectomies (217). The overall anastomotic leak rate was 3.8%. The mortality rate associated with anastomotic leak was 12.9%. In univariate analysis, the following parameters were associated with an increased risk for anastomotic dehiscence: (1) ASA score ≥ 3 (p = 0.004), (2) prolonged (>3 h) operative time (p = 0.02), (3) rectal location of the disease (p < 0.001), (4) and a body mass index > 25 (p = 0.04). In multivariate analysis, ASA score ≥ 3 (OR = 2.5; 95% CI 1.5–4.3, p < 0.001), operative time > 3 h [OR = 3.0; 95% CI 1.1–8.0, p = 0.02), and rectal location of the disease (OR = 3.75; 95% CI 1.5–9.0 (vs left colon), p = 0.003; OR = 7.69; 95% CI 2.2–27.3 (vs right colon), p = 0.001] were factors significantly associated with a higher risk of anastomotic dehiscence. Conclusions Three risk factors for anastomotic leak have been identified, one is patient-related (ASA score), one is disease-related (rectal location), the third being surgery-related (prolonged operative time). These factors should be considered in perioperative decision-making regarding defunctioning stoma formation.     

Role of the antiangiogenetic drug paclitaxel on healing of intestinal anastomosis: an experimental study

Background The aim of intraperitoneal administration of antineoplastic agents is the prevention of the implantation of tumoral cells after surgical intervention or the treatment of peritoneal carcinomatosis. The efficiency of intraperitoneal administration of paclitaxel, which is also an antiangiogenetic agent, has been investigated recently. The aim of this experimental study was to evaluate, taking into consideration its antiangiogenetic properties, the effects of intraperitoneal paclitaxel on healing of end to end colonic anastomosis. Methods 42 rats were allocated to 2 main groups (n = 21 for each group) to be evaluated on postperative day 3 (group A) and postoperative day 7 (group B). Each of the two main groups was divided into 3 subgroups (7 rats each). These subgroups were determined as control and two treatment groups administered paclitaxel in a dose of 2.5 mg/kg and 3.5 mg/kg intraperitoneally. Anastomosed segments of colon were harvested on postoperative day 3 or 7 and evaluated to determine bursting pressure of anastomoses, hydroxyproline levels and neovascularization with CD–31. Results In both groups, there were no significant differences between control and paclitaxel–treated groups with respect to bursting pressure. The level of hydroxyproline showed a significant decrease in all paclitaxel–treated groups compared with control groups (p = 0.001). Neovascularization was found to be decreased significantly on day 3 in the doses of paclitaxel 2.5 mg/kg (6.4 ± 1.63) and 3.5 mg/kg (5.89 ± 1.01) compared with control (8.02 ± 0.88) (p = 0.029 and p = 0.005, respectively). There were no significant differences in neovascularization in either groups on postoperative day 7. Conclusion We suggest that intraperitoneal administration of paclitaxel during surgical procedure decreases the hydroxyproline content and neovessel formation that are necessary for healing of intestinal anastomosis.     

Effects of Combined Pulse Electromagnetic Field Stimulation Plus Glutamine on the Healing of Colonic Anastomosis in Rats

Purpose An experimental study was designed to investigate the effect of combined pulse electromagnetic field (PEMF) stimulation plus glutamine administration on colonic anastomosis. Methods Anastomosis of the left colon was performed in 28 rats, which were divided into four groups; Group 1: normal resection anastomosis plus oral 50 mg/kg/day glutamine; Group 2: normal resection anastomosis plus PEMF stimulation plus oral 50 mg/kg/day glutamine; Group 3: normal resection anastomosis plus PEMF stimulation; Group 4: normal resection anastomosis. On the seventh postoperative day, the animals were killed and the bursting pressure and tissue hydroxyproline concentration of the anastomosis were analyzed and compared. Results The mean anastomotic bursting pressure in Group 2 was significantly higher than in Groups 1 and 4. On the other hand, the mean anastomotic bursting pressure in Group 1 was significantly higher than in Group 4. The collagen deposition and the fibroblast infiltration were significantly increased on the seventh day in Group 3 compared the other groups. On the other hand, Groups 1 and 2 had higher scores for collagen deposition and fibroblast infiltration than Group 4. Conclusions In conclusion, burst pressures, hydroxyproline, and histologic features (fibroblast infiltration and collagen deposition) were improved in the PEMF group, and both PEMF and glutamine-enriched nutrition provide a significant gain in the strength of colonic anastomoses in rats.     

Effect of Pentoxifylline on the Healing of Ischemic Colorectal Anastomoses

Purpose The aim of this study was to evaluate the effect of pentoxifylline on the healing of experimental ischemic colorectal anastomoses. Methods Ninety-three Wistar rats were randomized into three groups (n = 31) and underwent resection of a colonic segment at the colorectal junction. Group A rats received standard end-to-end anastomoses. Ischemic anastomoses were performed in Groups B and C rats by coagulating mesocolon vessels 2 cm along each anastomotic end. Group C rats were treated with intraperitoneal injection of pentoxifylline. Wound complications, intra-abdominal abscesses, intraperitoneal adhesions, and anastomotic leaks and stenosis were recorded. Bursting pressure and tension were calculated. Histologic examination of the anastomosis was also performed. Results Ischemia increased wound and intra-abdominal infections, adhesion formation, and anastomotic stenosis. Anastomotic leakage was significantly higher in Group B (45.2 percent) than in Group A (9.7 percent). Bursting pressure and tension were significantly lower in Group B (118.19 mmHg and 48.43 N/m) than in Group A (191.84 mmHg and 86.82 N/m). There was evidence for decreased perianastomotic fibrosis and neutrophils presence after induced ischemia and a strong tendency to reduced neovascularization. Pentoxifylline administration ameliorated the effects of ischemia, reducing wound and intra-abdominal infections, adhesion formation, and leaks (16.1 percent). Anastomotic strength increased (bursting pressure and tension of 205.55 mmHg and 87.68 N/m, respectively). Treated Group C had significantly higher neutrophils infiltration and fibrosis formation and a strong tendency to increased neovascularization compared with Group B. Conclusions Selective anastomotic devascularization induces ischemia and impairs experimental anastomotic healing, increasing leakage rate. These effects may be ameliorated by pentoxifylline administration. Supported by a grant from the “Servicio Andaluz de Salud,” Consejería de Salud, Junta de Andalucía.     

A prolonged interval between deep intestinal ischemia and anastomotic construction does not impair wound strength in the rat

Introduction Transient intestinal ischemia can reduce anastomotic strength, which poses an increased risk of complications. The objective of this study is to establish if a prolonged interval between profound ischemia and construction of an anastomosis affects anastomotic strength. Methods Male Wistar rats were used: in experimental groups, profound mesenteric ischemia was induced by clamping both superior mesenteric artery and more distal arteries in the ileal mesentery. Resection and anastomosis in ileum and colon were performed immediately (IR0) or 24 h after releasing the clamps (IR24). In controls (C0 and C24), arteries were not clamped. After 5 days, anastomotic bursting pressure (BP), breaking strength (BS), and hydroxyproline were measured, and histological analysis was performed. Results Mortality and anastomotic dehiscence rates were significantly higher in IR0 compared to C0. In ileum, the BS was 34% lower (p < 0.05) in IR0 compared to C0, while there were no significant differences in BS or BP between the IR24 and C24 groups. In colon anastomoses, although no differences in BS and BP were found, bursting site was at the anastomosis in 82% in group IR0 vs 30% in group C0, reflecting reduced anastomotic strength in the former. Again, after 24 h, there were no differences between IR and C group. Hydroxyproline and histology were not different between groups. Conclusions Extending the interval between transient deep intestinal ischemia and construction of an anastomosis does not impair wound strength.     

Healing of ischemic colonic anastomosis: Fibrin sealant does not improve wound healing

Fibrin adhesives have been advocated as a protective sealant in high-risk colonic anastomoses to prevent leakage. To assess the effect of fibrin glue sealing on the healing ischemic anastomosis, we compared the healing of sutured colonic anastomoses in the rat, with and without fibrin adhesive (Groups IA and IB), and ischemic anastomoses with and without fibrin adhesive (Groups IIA and IIB). On days two, four, and seven, 10 animals in each group were sacrificed. Adhesion formation was scored, and the in situ bursting pressure was measured. The collagen concentration and degradation were estimated by measuring hydroxyproline. Adhesion formation was more prominent in Groups IB, IIA, and IIB on day four only; abscesses were noted in the ischemic group in four rats. Anastomotic bursting pressure was significantly lower in sealed (IB) and ischemic anastomoses (IIA) than in normal anastomoses (IA) on day four. Sealing of ischemic anastomoses did not change bursting pressures on days two, four, and seven. The relative decrease of collagen in the sealed anastomoses is significantly higher on day four only. It is concluded that sealing of normal colonic anastomoses in the rat has a negative effect on wound healing. Ischemia at the anastomotic site results in weaker anastomotic strength on day four postoperatively. Also in ischemic anastomoses, fibrin sealant does not improve wound healing during the first seven days. Adhesion formation on ischemic intestinal anastomoses was not prevented by fibrin sealing.     

Transient Profound Mesenteric Ischemia Strongly Affects the Strength of Intestinal Anastomoses in the Rat

Purpose Experimental data suggest that transient preoperative ischemia and reperfusion may compromise anastomotic strength. However, data on this subject are equivocal, in particular as to the onset and duration of this effect. This study was designed to comprehensively characterize the effects of profound transient intestinal ischemia on anastomotic healing during the first postoperative week. Methods Ischemia was induced in rats by clamping both the superior mesenteric artery and ileal branches for 30 minutes. Immediately after declamping, anastomoses were constructed in both terminal ileum and descending colon. After three, five, or seven days, both bursting pressure and breaking strength were measured. Anastomotic collagen content, gelatinase activity, and histology were analyzed. Results Anastomotic leakage rate was 13 percent in ischemia-reperfusion group and 0 percent (P = 0.02) in controls. The breaking strength in ileum remained significantly (P < 0.05) lower in the ischemic groups than in the control groups at all time points. Bursting pressure in the ileum was not significantly different between ischemic and control groups at either of the time points measured. However, at Day 7 the bursting site was significantly more frequent within the suture line in the ischemic groups. In the colon, at Day 3 the bursting pressure was 35 percent lower in the ischemic group than in the control group (P < 0.05). Anastomotic collagen content and gelatinase activity were similar in ischemic and control groups. Conclusions Transient profound splanchnic ischemia compromises anastomotic strength throughout the entire first postoperative week. This effect does not seem to be caused by impaired accumulation of wound collagen. Presented at the meeting of the European Society for Surgical Research, Konya, Turkey, May 25 to 28, 2005.     

Risk factors for mortality–morbidity after emergency–urgent colorectal surgery

Background  The aim of this study was to assess the risk factors associated with mortality and morbidity following emergency or urgent colorectal surgery. Materials and methods  All data regarding the 462 patients who underwent emergency colonic resection in our institution between November 2002 and December 2007 were prospectively entered into a computerized database. Results  The median age of patients was 73 (range 17–98) years. The most common indications for surgery were: 171 adenocarcinomas (37%), 129 complicated diverticulitis (28%), and 35 colonic ischemia (7.5%). Overall mortality and morbidity rates were 14% and 36%, respectively. In multivariate analysis, the only parameter significantly associated with postoperative mortality was blood loss >500 cm³ (odds ratio (OR) = 3.33, 95% confidence interval (CI) 1.63–6.82, p = 0.001). There were three parameters which correlated with postoperative morbidity: ASA score ≥3 (OR = 2.9, 95% CI 1.9–4.5, p < 0.001), colonic ischemia (OR = 3.4, 95% CI 1.4–7.7, p = 0.006), and stoma creation (OR = 2.2, 95% CI 1.4–3.4, p = 0.0003). Conclusions  The main risk factors for postoperative morbidity and mortality following emergency colorectal surgery are related to: (1) patients’ ASA score, (2) colonic ischemia, and (3) perioperative bleeding. These variables should be considered in the elaboration of future scoring systems to predict outcome of emergency colorectal surgery.     

Growth hormone increases the bursting strength of colonic anastomoses

The effect of growth hormone on the bursting strength of left colonic anastomoses was investigated experimentally. Seventy-two 3 month-old female rats were randomized into two groups receiving daily injection of either saline (controls) or 2.0 mg biosynthetic human growth hormone per kg body weight per day. All injections were started 7 days before a left colonic resection and anastomosis, and continued until sacrifice at the 2nd, 4th or 6th post-operative day. The bursting strength of the anastomoses was tested in anaesthetized, living rats. The bursting pressure and the bursting wall tension of the growth hormone treated animals were increased two-fold on the second post-operative day (2p<0.005) and three-fold on the fourth post-operative day (2p<0.05), compared with controls. There was no difference in the bursting pressure or the bursting wall tension on the sixth postoperative day. The mass of the resected segment was incresed by the pre-operative growth hormone treatment, whereas the hydroxyproline content was unchanged. In conclusion, treatment with biosynthetic human growth hormone increases the strength of colonic anastomoses in the early phases of healing.