Hyaluronic acid-based agents do not affect anastomotic strength in the rat colon, in either the presence or absence of bacterial peritonitis

BACKGROUND: Hyaluronic acid (HA) agents reduce postsurgical adhesion formation. The effect of their perioperative administration on early anastomotic healing is unknown. This study investigated the influence of two HA-containing agents on the development of strength in colonic anastomosis during the first postoperative week, both in normal rats and in rats with bacterial peritonitis. METHODS: In 90 male Wistar rats a 1-cm segment was resected from the descending colon and an end-to-end anastomosis was constructed. In 108 rats a bacterial peritonitis was induced using caecal ligation and puncture (CLP). Some 24 h after CLP the abdomen was reopened, the caecum was taken out and, after resection of a 1-cm segment, an anastomosis was made. Animals in both groups were randomized to receive either an HA-carboxymethylcellulose (CMC) bioresorbable membrane, 0.4 per cent HA solution or no treatment. One-third of each group was killed at day 1, 3 and 7 after operation. Cultures were taken from the abdominal cavity for microbiological analysis in half of the animals. Subsequently, both bursting pressure and breaking strength were determined as parameters for anastomotic strength. RESULTS: No differences in anastomotic bursting pressure or breaking strength were found between the experimental groups and their controls. In addition, there was no significant difference in the number of bacteria cultured from the abdominal cavity between rats treated with HA and controls. CONCLUSION: Neither HA-CMC bioresorbable membrane nor 0.4 per cent HA solution interferes with the development of early anastomotic strength in the colon, and can therefore be safely used to prevent intra-abdominal adhesion formation after performing bowel anastomosis.     

Doxycycline improves wound strength after intestinal anastomosis in the rat

BACKGROUND: The strength of intestinal anastomoses is relatively low in the first days after operation, possibly as a result of localized degradation of the supporting matrix by enzymes from the matrix metalloproteinase (MMP) family. The aim of this study was to examine whether doxycycline, a drug known to inhibit MMP activity, could enhance anastomotic strength. METHODS: Male Wistar rats received anastomoses in both ileum and colon. From the day before operation onwards, animals were treated daily with doxycycline (orally or subcutaneously) in a dose of 10 mg/day or with saline only. Rats were killed 1, 3, or 5 days after operation, and anastomotic bursting pressure and breaking strength were measured. At day 3, anastomotic hydroxyproline levels were measured, MMP (gelatinase) activity was analyzed by gelatin zymography, and anastomotic histology was examined. RESULTS: Doxycycline enhanced wound strength, but only at day 3, when it was at its lowest. Subcutaneous administration of 10 mg/day increased median colonic and ileal breaking strength by 27% (P =.0019) and 104% (P =.0376), respectively. Colonic bursting pressure was increased by 93% (P =.0002). Wound histology was similar in experimental and control groups. CONCLUSIONS: Administration of doxycycline enhances anastomotic strength and should be investigated further as a means to preserve anastomotic integrity.     

Early Anastomotic Repair in the Rat Intestine is Affected by Transient Preoperative Mesenteric Ischemia

Introduction  During bowel surgery, perioperative blood loss and hypotension can lead to transient intestinal ischemia. Recent preclinical studies reveal that the strength of intestinal anastomoses can be compromised after reperfusion. So far, this phenomenon has not been investigated in the very first days of healing when wound strength is lowest. Material and Method  Ischemia was induced in rats by clamping both the superior mesenteric artery and ileal branches for 30 min. Immediately after declamping, anastomoses were constructed in both terminal ileum and descending colon. The same was done in control groups after sham-ischemia. Anastomotic bursting pressure and breaking strength were measured immediately after operation (day 0) and after 1, 2, or 3 days. Anastomotic hydroxyproline content, gelatinase activity, and histology were analyzed. Results and Discussion  In ileal anastomoses, at day 1, both the breaking strength and bursting pressure were significantly (p < 0.05) lower in the ischemic group, while at day 2, this was the case for the bursting pressure only. In the colon, the bursting pressure in the ischemic group was lower at day 1. Anastomotic hydroxyproline content remained unchanged. Increased presence of the various gelatinase activities was found in ileum only at day 0 and in colon at days 1 and 2. Histological mucosal damage was found in ischemia–reperfusion groups. Conclusion  Transient mesenteric ischemia can negatively affect anastomotic strength during the very first days of healing, even if the tissue used for anastomotic construction looks vital.     

Effects of two conventional preoperative radiation schedules on anastomotic healing in the rat colon

BACKGROUND: Preoperative radiotherapy (RT) is an increasingly popular form of adjunct therapy for rectal cancer; however, little is known about its effects on matrix metalloproteinase (MMP) expression in colonic anastomotic healing. METHODS: Wistar rats were irradiated to a total dose of 25 or 40 Gy. Four days after the end of RT, an end-to-end colorectal anastomosis was performed. Animals were sacrificed at 1, 3, and 7 days after the anastomosis. A control group was studied similarly, but was not irradiated. RESULTS: No significant differences were found in peritonitis rate and anastomotic complications. The average bursting pressure and breaking strength were only reduced significantly in the rats irradiated with 40 Gy. However, the concentration and the content of hydroxyproline in anastomotic tissues were unchanged. In irradiated rats, MMP-2 and MMP-9 were significantly increased at 40 Gy, but not at 25 Gy. On the other hand, 25-Gy irradiation induced a smaller increase in the levels of the tissue inhibitors of metalloproteinase-1 compared with the controls. CONCLUSION: Anastomotic strength is adversely affected by high-dose fractionated preoperative RT. In contrast, preoperative RT at 25 Gy in five fractions over 5 days is safe with regard to the maintenance of wound strength in colorectal anastomosis.     

Selective cyclo-oxygenase 2 inhibition affects ileal but not colonic anastomotic healing in the early postoperative period

BACKGROUND: Selective cyclo-oxygenase 2 (COX-2) inhibitors are increasingly prescribed in the perioperative period. Recent recognition of a possible role for COX-2 in wound healing has raised concerns about the safety of their use in surgical practice. Therefore, the influence of celecoxib, a selective COX-2 inhibitor, on early anastomotic healing was investigated. METHODS: Celecoxib, in doses of 15, 50 or 200 mg per kg per day, was given daily from the day before operation onwards to male Wistar rats that received both ileal and colonic anastomoses. Anastomotic strength was assessed by measuring the breaking strength and bursting pressure on the third day after operation. A second group received a dose of 50 mg per kg per day and a colonic anastomosis only, and healing was assessed on the third and fifth day after surgery. RESULTS: Expression of COX-2 protein was upregulated in the anastomotic area. Administration of celecoxib, at all doses tested, resulted in a significantly higher ileal dehiscence rate than in control rats (P = 0.002). In contrast, colonic anastomoses healed normally within the same animals. The latter was confirmed in rats with colonic anastomoses only. CONCLUSION: In this model, administration of the COX-2 inhibitor celecoxib affected ileal but not colonic anastomotic healing in the early postoperative period.     

Latex rubber (Penrose drain) is detrimental to esophagogastric anastomotic healing in rats

BACKGROUND: Surgeons commonly drain cervical esophagogastric anastomoses, but there is little objective evidence to support this practice. Studies in other areas of gastrointestinal surgery have shown that routine drainage is unnecessary, and even detrimental to anastomotic healing. We conducted an animal experiment to see if a drain had a negative effect on esophagogastric anastomotic healing. METHODS: Esophagogastric anastomoses were done in 40 rats. In the experimental group (20 rats) a portion of latex rubber Penrose drain was placed over the anastomosis. This was not done in the control group (20 rats). Rats were sacrificed 7 days after surgery. The anastomoses were inspected for leaks, distracted in a tensiometer to measure breaking strength, and subjected to hydroxyproline analysis (an indicator of wound collagen). RESULTS: There were 4 contained leaks in the experimental group (drain) and no leaks in the control rats (p=0.033). Anastomotic breaking strength was 3.80+/-0.81 N in the experimental rats and 3.46+/-0.64 N in the control rats (p=0.18, not significant). Anastomotic tissue hydroxyproline concentration was 615.9+/-52 nmol/mg in the experimental rats and 609.4+/-195 nmol/mg in the control rats (p=0.13, not significant). CONCLUSIONS: The presence of drain material predisposed to esophagogastric anastomotic leakage in this rat model.     

Ischemia and prolonged reperfusion before anastomotic construction do not reduce wound strength in the rat intestine

BACKGROUND: Under certain conditions, transient intestinal ischemia can reduce anastomotic strength. Preliminary findings suggest that prolonged reperfusion time, before anastomotic construction, results in reduced wound strength. The purpose of this study is to determine if wound strength indeed decreases with increasing duration of the interval between an ischemic period and construction of an anastomosis. METHODS: In male Wistar rats, ischemia was induced by crossclamping the superior mesenteric artery (SMA) for 40 minutes. In control groups, the SMA was exposed but not clamped. Resection and anastomosis in both ileum and colon were performed immediately after release of the clamp or after 90 minutes or 24 hours. Both the anastomotic bursting pressure and breaking strength were measured after 3 or 5 days, together with hydroxyproline levels. RESULTS: Neither bursting pressure nor breaking strength, either in ileum or in colon, changed significantly when the time between the end of ischemia and anastomotic construction increased. Similar values were obtained in all experimental and corresponding control groups. In the group in which anastomoses were constructed after 24-hour reperfusion, mechanical strength increased significantly from day 3 to day 5 and at the same rate as in the control group. No differences in anastomotic hydroxyproline levels were found between experimental and control groups analyzed at day 5. CONCLUSIONS: A prolonged interval between intestinal ischemia and anastomotic construction does not affect development of early wound strength. Therefore, delayed anastomosis after transient ischemia is not likely to increase the risk of anastomotic complications.     

Blood transfusion impairs the healing of experimental intestinal anastomoses.

Blood transfusions are reported to impair the cell-mediated immune response. Because both T lymphocyte and macrophage function are important for wound repair, the authors investigated the effect of blood transfusions on anastomotic repair. Lewis rats underwent resection of both ileum and colon, followed by the construction of either an everted or an inverted end-to-end anastomosis. Immediately after operation, they received either 3 mL saline intravenously, or 3 mL heparinized blood from Lewis or Brown Norway donors. The animals were killed 3 or 7 days after operation, and anastomotic strength was assessed by measuring the bursting pressure. Anastomotic abscesses and generalized peritonitis were not found in the control group. Blood transfusions, particularly allogeneic, significantly increased the incidence of these septic complications. Three days after operation, anastomotic strength was significantly reduced in both Lewis and Brown Norway transfused groups. For instance, average bursting pressures (+/- standard deviation [SD]) of inverted ileal anastomoses were 79 +/- 13 mmHg in the control group and 46 +/- 14 and 21 +/- 12 mmHg in the Lewis and Brown Norway transfused groups, respectively. Seven days after operation, the rupture site was found significantly more often within the anastomotic line in the animals that had received blood transfusions. The authors conclude that blood transfusions impair the healing of experimental intestinal anastomoses and increase susceptibility to intra-abdominal sepsis.     

Healing of experimental colonic anastomoses. II. Breaking strength of the colon after left colon resection and anastomosis.

Mechanical strength of the left colon with anastomosis and the intact transverse colon was studied by breaking strength tests performed from four to twenty-eight days after standardized left colon resection in the rat. Two different single layer inverting suture technics were used, continuous and interrupted.Breaking strength of the colon in unoperated rats paralleled to a certain extent the collagen concentration of the colonic wall, with highest values of strength in the left colon where collagen concentration is highest.Both types of anastomoses showed a rapid and equal gain in strength between days 4 and 10, after which time the increase in strength occurred at a much slower rate. After ten days the anastomosis had gained approximately 50 per cent of the strength of the left colon in unoperated control rats. Four weeks after the operation the anastomoses made of continuous suture had reached 75 per cent of normal breaking strength and were significantly stronger than those made of interrupted sutures, which had gained only about 55 per cent of normal strength.Breaking strength test measured the strength of the anastomosis throughout the four week period of investigation, since the rupture always occurred in the anastomotic line.Breaking strength determinations of the intact transverse colon did not show any alterations from normal during the healing course as did determinations of bursting strength reported in a previous study.In skin wounds breaking strength showed a constant development of strength during the four week investigation period, while the gain in strength of the anastomosis slowed down after ten days, although it had only reached 50 per cent of normal.     

The Effect of Purified Micronized Flavonoid Fraction on the Healing of Anastomoses in the Colon in Rats

Purpose Anastomotic leakage of colonic and rectal anastomoses is a major complication after large intestine surgery. Many factors influence the healing of colon anastomoses. Flavonoids have been recognized for centuries as physiologically active constituents that are used to treat human diseases. We studied the effects of a clinically used, micronized, purified flavonoid fraction on the healing of colonic anastomosis in rats. Methods Male Sprague–Dawley rats were used. The flavonoid group of rats received 100 mg/kg per day of Daflon for 14 days until surgery. Thereafter, a resection and anastomosis were performed. The bursting pressure of the anastomoses and the hydroxyproline levels of the perianastomotic tissue were determined to evaluate the healing on the third and seventh days of surgery for both flavonoid and control groups. Results The bursting pressure of the flavonoid group was higher on the seventh day. The hydroxyproline levels of the flavonoid group were significantly higher than in the control group on both the third and seventh days after surgery. Conclusions Although the micronized purified flavonoid fraction has some inhibitory properties on the healing of the anastomosis, its net effect was to obtain a better anastomotic healing of the colon in rats.     

Effect of mechanical bowel preparation on anastomotic integrity following low anterior resection in dogs

To assess the effect of mechanical bowel preparation on anastomotic integrity after low anterior resection, 36 mongrel dogs were randomized to have low anterior resection with or without mechanical bowel preparation. All dogs received prophylactic antibiotics and anastomotic integrity was assessed on the ninth postoperative day by barium enema, inspection of anastomoses for defects after careful excision at laparotomy, and anastomotic bursting pressures. Bursting pressures were significantly higher (P less than 0.005) in the group with bowel preparation. Anastomotic defects were present in 13 per cent of animals with bowel preparation and 47 per cent without bowel preparation (P = 0.057). Pelvic abscess and death from peritonitis occurred in 6 per cent of the group with bowel preparation and 29 per cent of the unprepared group. Mechanical bowel preparation significantly enhanced anastomotic integrity and reduced complications in this model.     

Inhibition of matrix metalloproteinases enhances breaking strength of colonic anastomoses in an experimental model

BACKGROUND: The breaking strength of colonic anastomoses declines after operation to a minimum at days 3-4, with a subsequent risk of anastomotic dehiscence. The mechanism is thought to be collagen degradation by matrix metalloproteinases (MMPs). This study examined the pathogenic role of MMPs on the mechanical strength of colonic anastomoses by giving the synthetic broad-spectrum MMP inhibitor BB-1101 systemically. METHODS: Forty-eight male Sprague-Dawley rats were treated daily for 7 days with BB-1101 30 mg/kg or vehicle alone (control) starting 2 days before operation. The breaking strength of standardized left-sided colonic anastomoses was measured on postoperative days 1, 3 and 7. RESULTS: Serum BB-1101 levels were increased at 100 nmol/l in BB-1101-treated rats. The anastomotic breaking strength was 48 per cent higher (P = 0.02) in BB-1101-treated animals compared with controls on postoperative day 3. Neither collagen accumulation nor infiltration of neutrophils in the anastomotic area was influenced by BB-1101 treatment. Net deposition of new collagen in subcutaneous sponges was unaffected by the BB-1101. CONCLUSION: The enhanced breaking strength of colonic anastomoses during the critical early postoperative phase found after administration of a broad-spectrum MMP inhibitor implies that MMPs might increase the risk of anastomotic dehiscence. Presented in part to the third joint meeting of the European Tissue Repair Society and the Wound Healing Society in Bordeaux, France, 24-28 August 1999, and published in abstract form in Wound Repair Regen 1999; 7: A321     

The Effects of Simvastatin on Ischemia Reperfusion Injury in an Experimental Colon Anastomosis Model

Anastomotic leakage is more frequently reported in colonic anastomoses. Ischemia reperfusion injury is one of the main reasons for anastomotic leakage. Simvastatin is known to prevent tissue damage induced by free oxygen radicals after ischemia reperfusion injury. The effect of simvastatin on colonic anastomosis impaired by ischemia reperfusion injury is investigated. Single layer, end-to-end colocolic anastomosis after 0.5-cm colon resection was performed in Wistar Albino rats. In Group 1 (control) (n?=?10), colonic anastomosis without I-R was performed. In Group 2 (n?=?10), the superior mesenteric artery was clamped for 10 min followed by 60 min of reperfusion after which resection anastomosis was performed. In Group 3 (n?=?10), 10 mg/kg simvastatin was given by gavage for 7 days after I-R and resection anastomosis. In Group 4 (n?=?10), the rats received 10 mg/kg simvastatin by gavage 7 days before and 7 days after ischemia reperfusion and surgery. All of the rats were sacrificed 8 days after surgery. Anastomotic bursting pressure and tissue hydroxyproline levels were measured. Postoperative administration of simvastatin restored the anastomotic bursting pressure and hydroxyproline levels to that of control group thus overcoming the effect of ischemia reperfusion injury. Simvastatin administered postoperatively in an experimental model of colonic resection anastomosis impaired by ischemia reperfusion injury increased anastomotic bursting pressures and tissue hydroxyproline levels. Further experimental and clinical studies will show whether administration of simvastatin will increase reliability of the anastomosis and decrease postoperative morbidity and mortality in colonic anastomosis after ischemia reperfusion injury.     

Effects of the intraperitoneal lornoxicam on the formation of intraperitoneal adhesions in rat peritonitis model

BACKGROUND: To investigate the effects of intraperitoneally administered lornoxicam on adhesion formation, bursting pressure, tissue antioxidant levels, morbidity and mortality after ileocolic anastomosis in a rat bacterial peritonitis model. METHODS: Thirty-six rats were divided into three random groups. Bacterial peritonitis was induced by performing a cecal ligation and puncture, then the cecal was resected and ileocolic anastomosis was performed. Rats of groups 1, 2 and 3 were given 2 mL normal saline, 2 mL lornoxicam, and nothing, respectively. All groups were killed at day 14. Adhesions were scored, and the presence of intra-abdominal abscesses and fistulas were noted. Anastomotic healing was assessed by bursting pressure. Tissue antioxidant levels were tested from left abdominal walls. RESULTS: One day after cecal ligation and puncture, microbiological examination showed polymicrobial bacterial peritonitis. The rats treated with lornoxicam had significantly lower adhesion scores than did the saline and nothing treated rats (P = 0.007). Bursting pressures of groups were unaffected by the treatment. Tissue antioxidant levels of groups were affected by the treatment. Morbidity and mortality were similar in all groups. CONCLUSIONS: The present study demonstrated that a single intraperitoneal instillation of lornoxicam in buffer solution at the end of the surgery reduces adhesion formation in rats bacterial peritonitis model. It was also determined that lornoxicam had no negative effect on the healing of intestinal anastomosis, abscess and anastomotic leakage. Use of lornoxicam in peritonitis was effective in decreasing the oxidative stress of tissue during peritonitis.     

Is synchronous bowel anastomosis safe?

In this study, we investigated the effects of synchronous anastomosis on intestinal healing in experimental colonic resection. Sprague-Dawley rats were randomized into 3 groups; control (group I), single anastomosis (group II) and synchronous (double) anastomosis (group III). Single and proximal anastomoses were located 3 cm distal to caecum, and distal anastomoses were done 3 cm distal to them. On the 7th postoperative day, bursting pressure, hydroxyproline level and histology of the anastomotic site were assessed. Bursting pressures and hydroxyproline levels indicated that impaired healing of proximal anastomoses in group III was evident. Proximal anastomoses in group III had the lowest hydroxyproline value and bursting pressure level. Significant fibrosis was observed in the histological examination of distal anastomoses in group III. Double colonic anastomoses is not as safe as single anastomoses and involves additional risk. The healing of proximal anastomosis is significantly altered after experimental synchronous resection.     

Effect of the combination of fibrin glue and growth hormone on incomplete intestinal anastomoses in a rat model of intra-abdominal sepsis

BACKGROUND: The presence of established intra-abdominal sepsis has been considered a contraindication to primary anastomoses. Our hypothesis was that fibrin glue (FG), growth hormone (rhGH), and combination of them synergistically improve intestinal primary anastomotic healing in a rat model of intestinal fistulae with peritonitis. MATERIALS AND METHODS: Male Wistar rats, induced intestinal fistulae with peritonitis after 24 h, were performed an enterectomy and intestinal anastomoses. Group A, rats (n = 60) had a complete anastomoses (end-to-end single layer anastomoses using 12 inverted interrupted 6-0 sutures) without peritonitis, group B, rats (n = 60) had a complete anastomoses after 24 h of peritonitis, group C rats had an incomplete anastomoses (four inverted interrupted sutures), groups D, E, F rats (n = 60) received FG, rhGH, or both of them, respectively. rhGH was given daily for 5 days. Anastomoses indicated the anastomotic bursting pressure (ABP), tensile strength, and hydroxyproline content, were determined. RESULTS: On POD 1, ABP of group C and group D was significantly lower than that of other groups (P < 0.01); On POD 3, ABP could not be determined because of intestinal dehiscence in groups C and E, ABP was significantly higher in groups D and F than that of groups A and B (P < 0.01); the ABP increased after 5 days of operation in groups A, B, and F. At the same time, that of group D decreased (P < 0.01). On POD 5, the tensile strength was significantly higher in groups A, D, and F than that in groups C, and E. On POD 5, hydroxyproline content was higher in groups D and F compared to that in group C (P < 0.05). CONCLUSIONS: These data suggested that FG improve intestinal primary anastomotic healing within post-operative 5 days in a rat model of intestinal fistulae with peritonitis. RhGH alone fails to improve intestinal anastomotic healing, and the combination of FG and rhGH have no synergistic effect to improves intestinal anastomotic healing.     

Healing of experimental colonic anastomoses. I. Bursting strength of the colon after left colon resection and anastomosis.

Mechanical strength of the left colon with anastomosis and the intact transverse colon was studied by the bursting strength technic from four to fourteen days after standardized left colon resection in the rat. Two different single layer inverting suture technics were used, continuous suture and interrupted sutures. Bursting strength was tested by determinations of both bursting pressure and bursting wall tension, both of which provided the same information concerning mechanical strength of the colon. The bursting strength test measures the anastomotic strength only during the early stages of healing, since more than 90 per cent of the left colon segments ruptured outside the anastomosis as early as day 7. The two different suture technics resulted in the same bursting strength of the left colon segment with anastomosis. Both types of anastomoses showed a moderate narrowing at the anastomotic line upon inflation. This was due to the fact that the anastomosis constituted a relatively firm fibrotic ring from day 7, and both types of anastomoses had an equal inner diameter at that time. By supporting the colonic wall above and below the anastomosis, it could be calculated that the anastomosis on day 7 withstood at least 50 per cent higher circular wall tension than the surrounding colonic wall.There was no correlation between collagen concentration of the colonic wall and bursting strength of the colon either in unoperated controls or after resection and anastomosis. When interrupted sutures were used for anastomosis of the left colon, bursting strength of the intact transverse colon was significantly higher on day 7 than when continuous suture was used. It actually exceeded that of the transverse colon in unoperated controls by almost 50 per cent on the seventh postoperative day, although the collagen concentration in the transverse colon was within normal range. This finding indicated changes in the proximal colonic wall after left colon resection, which are probably related to changes in the structure or arrangement of collagen.     

Effect of supplemental vitamin A on the healing of colon anastomosis

The effect of dietary supplementation with vitamin A on the healing of colon anastomoses was studied. Fifty adult male Sprague-Dawley rats were divided into two groups: (1) rats fed a standard chow which contains the equivalent of about 15 IU vitamin A/g diet; (2) rats fed the chow supplemented with an additional 150 IU vitamin A/g diet. Rats were prefed for 5 days; on Day 6 under ether anesthesia the colon was divided 1-in. distal to the ileocecal junction and then reanastomosed. The rats were maintained on the above diets for 5 days and killed on the sixth postoperative day with ether and the segment of colon containing the anastomosis was resected. In 15 rats of each group, the breaking strength of the anastomosis was measured. In the remaining 10 rats of each group, the bursting strength of the anastomotic site and a segment of normal distal colon was measured. Samples of colon from the anastomotic site and the normal segment were analyzed for hydroxyproline. There was a significant decrease in hydroxyproline content at the anastomotic site when compared to the normal distal colon segment in each group of rats (P < 0.01). The hydroxyproline content of both normal colon and the anastomotic site was significantly higher in the vitamin A-supplemented rats than in the control diet rats (P < 0.01). There was also a significant increase in bursting strength in the vitamin A-supplemented rats both of the anastomotic site (P < 0.01) and of the normal colon segment (P < 0.01). The anastomotic breaking strength peak values did not differ significantly between the two groups, but the area under the breaking strength curve (an expression of the energy required to break the anastomosis) was three times greater in the vitamin A-supplemented rats than in the controls (P < 0.001). It is concluded that vitamin A supplementation has a beneficial effect on the healing of colon anastomoses in rats.     

Comparison of anastomotic suturing techniques in the rat esophagus.

BACKGROUND: Long-gap esophageal atresia continues to be a challenging pediatric thoracic surgical problem. Despite the use of various tension relieving procedures, the esophageal anastomosis is often performed under considerable tension. Excessive tension can cause anastomotic sutures to pull through the esophageal tissue, with resultant early esophageal anastomotic dehiscence. To test the hypothesis that interrupted horizontal mattress sutures would withstand the forces of tension better than interrupted simple sutures, an experimental study of rat esophageal anastomoses was done. METHODS: Twenty rats were killed and their esophagi were excised. The esophagi were divided in the mid portion and end-to-end anastomoses were done using interrupted 6-0 polypropylene sutures. Ten rats had anastomoses done with interrupted simple sutures and ten had interrupted horizontal mattress suturing. Anastomotic breaking strength was tested in a tensiometer. RESULTS: Anastomotic breaking strength was 3.22+/-0.56 N for the interrupted simple sutured anastomoses and 3.51+/-0.61 N for the interrupted horizontal mattress group (p=0.30). The difference was not significant. CONCLUSIONS: In this animal study interrupted simple and horizontal mattress suturing withstood the disruptive forces of anastomotic tension equally well.     

Hyaluronic acid/carboxymethylcellulose membrane surrounding an intraperitoneal or subcutaneous jejunojejunostomy in rats.

OBJECTIVE: To investigate the healing of intra-abdominal and extra-abdominal jejunal anastomoses that were surrounded by a hyaluronic acid/carboxymethylcellulose membrane (Seprafilm) in rats. DESIGN: Laboratory study. SETTING: University hospital, The Netherlands. ANIMALS: 56 male Wistar rats. INTERVENTIONS: 28 rats had jejunojejunostomies placed subcutaneously and 28 had them placed intra-abdominally. Half of each group of anastomoses were surrounded by Seprafilm. MAIN OUTCOME MEASURES: After 3 or 7 days, the anastomoses were tested for bursting pressure, tensile strength, and hydroxyproline concentrations. RESULTS: There were numerous strong adhesions around the anastomoses in the subcutaneous position and Seprafilm had no influence on their extent. Bursting pressure and hydroxyproline concentrations were not affected by position or Seprafilm treatment. Tensile strength was significantly higher in the subcutaneous position (p < 0.01), but was unaffected by Seprafilm. CONCLUSION: Anastomotic healing was not impaired in the subcutaneous or intraperitoneal position in this model. Seprafilm had no effect on the anastomosis.