Anastomotic Bursting Pressure Research Articles

Effect of the Combination of Fibrin Glue and Growth Hormone on Incomplete Intestinal Anastomoses in a Rat Model of Intra-Abdominal Sepsis

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. 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. 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). 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.

Increased Burst Pressure in Gastrointestinal Staple-Lines using Reinforcement with a Bioprosthetic Material

Leakage at an anastomosis is a major and often catastrophic complication of gastrointestinal (GI) surgery. Staple-line reinforcement with one of the several materials commercially available has been utilized to reduce the incidence of this complication. The bioprosthetic material, small intestinal submucosa (SIS, Surgisis((R)); Cook, Inc., Bloomington, IN) has found widespread applications in surgery. However, its ability to improve the durability of staple-lines in GI surgery in terms of burst pressure has not been documented. We hypothesized that SIS reinforcement of staple-lines in healthy living GI tissue would increase durability, as determined by leak rates at increased intraluminal pressures, compared to unreinforced staple-lines. Two healthy Yorkshire-Cross pigs were subjected to midline laparotomy and underwent small intestinal division (n=28) with GIA stapling devices. Half of the staple-lines were reinforced with SIS. The staple-lines were then exposed to increased intraluminal pressures by means of a constant-rate dye solution infusion, until staple-lines exhibited visible leakage of the dye solution. The intraluminal pressure was recorded at the time of visible leakage. Staple-lines reinforced with SIS had significantly better durability as determined by analysis of variance and Kaplan-Meier survival calculations, with respect to leak rate as a function of intraluminal pressure (P<0.003). The mean burst pressure of the unreinforced staple-lines was 53 mmHg, while those staple-lines reinforced with SIS had a mean burst pressure of 83 mmHg. Reinforcement of stapled GI anastomoses with SIS significantly increases anastomotic burst pressure. These findings suggest a role for this material in GI surgery.

Anastomotic Healing in a Small Bowel Transplantation Model in the Rat

Anastomotic healing is impaired after intestinal surgery because of ischemia and reperfusion injury (IRI), which can result in intestinal leaks leading to increased mortality. The objective of this study was to determine the effects of transplant IRI and immune mechanisms on intestinal graft anastomotic healing. Orthotopic intestinal transplantations (OIT) were performed in rats. The experimental design consisted of six groups A-F (n=5/group): A, allogeneic OIT treated with tacrolimus (1 mg/kg/day); B, syngeneic OIT treated with tacrolimus; C, syngeneic OIT; D, allogeneic OIT; E, proximal and distal anastomoses performed in nontransplanted animals; F, same as in group E but treated with tacrolimus. Anastomotic bursting pressure (ABP), hydroxyproline content (HPC), and mucosal inflammatory infiltrate (MII) were determined at the anastomotic sites (proximal and distal) and compared between groups. ABP was significantly (p<0.001) reduced in OIT groups A, B, C, and D compared to control groups E and F at both the proximal and distal anastomotic sites. HPC was approximately 1 microg/mg of tissue in groups A, B, C, and D, and approximately 5 microg/mg of tissue in groups E and F. This demonstrates a significant (p<0.001) reduction in HPC after OIT. MII was significantly (p<0.001) increased in OIT groups when compared to nontransplanted control groups. MII was also significantly (p<0.05) increased in allogeneic OIT groups A and D compared to syngeneic OIT groups B and C. Generally, ABP and HPC were inversely proportional to MII in both nontransplanted control and OIT groups. Reduced anastomotic strength was demonstrated in both syngeneic and allogeneic OIT anastomotic sites irrespective of immunosuppressive therapy, and is probably related to IRI.

The effect of pentoxifylline on intestinal anastomotic healing after ischemia.

The negative effects of ischemia-reperfusion injury (IRI) on intestinal anastomotic healing have been described in previous studies. To determine the effect of pentoxifylline (PTF) on small-bowel anastomoses performed after IRI, 20 male Wistar albino rats were studied. Under ketamine anesthesia, the superior mesenteric artery was occluded for 30 min and ileal resection-anastomosis was performed after 10 min of reperfusion. In group I, no medication was given. In group II, PTF 50 mg/kg was administered intraperitoneally before reperfusion and i.m. on the 1st, 2nd, 3rd and 4th postoperative days (POD). All rats were killed and anastomotic segments were removed on the 7th POD. Anastomotic bursting pressure (ABP) and hydroxyproline (HP) content were measured in the anastomotic segments; parameters were compared statistically with Student's t-test. In group I, the mean ABP was 225.5 +/- 38.18 mmHg the and mean HP level was 16.03 +/- 1.91 micro mol/g tissue. In group II, these levels were 277 +/- 41.1 mmHg and 19.85 +/- 1.81 micro mol/g tissue, respectively. The differences between the groups were significant (P < 0.005). Thus, PTF can improve anastomotic healing in an experimental model after IRI by promotion of collagen synthesis.

Local Expression of Tumor Necrosis Factor-α and Interleukin-10 on Wound Healing of Intestinal Anastomosis During Endotoxemia in Mice

Background. This study aimed to evaluate the integrity of anastomotic wound healing after digestive surgery under septic conditions and define the participation of local expression of tumor necrosis factor-α (TNF-α) and interleukin-10 (IL-10) around the anastomotic segment. Materials and methods. Experimental animals were divided into lipopolysaccharide (LPS) and control groups, which had either LPS or normal saline solution injected into the peritoneal cavity 24 h before transection and anastomosis of the colon. Anastomotic bursting pressure (ABP) and tissue hydroxyproline concentration (HP) were measured as indicators of wound healing. Immunohistochemical staining for TNF-α and IL-10 on tissue samples obtained from the anastomotic segment were examined 1, 6, and 24 h after the operation. The reactive cells were counted under light microscopy. Results. ABP and HP were significantly lower in the LPS group than in the control group 7 days after surgery. In the LPS group, TNF-α expression increased about threefold over that in the control group 1 h after the operation. TNF-α-reactive cells were observed until 24 h after the operation in the LPS group, but not in the control group. On the other hand, IL-10 was not expressed in the control group during the observed period, whereas IL-10 was observed 24 h after the operation in the LPS group. Conclusions. It is suggested that anastomotic wound healing was impaired after the digestive surgery in animals treated with intraperitoneal LPS, and that local expression of TNF-α and IL-10 at the anastomotic site acts as an inhibitory factor in the wound healing process.

Effect of acute anemia on the healing of intestinal anastomoses in the rabbit.

Considering the potential deleterious effects of transfusion, the effect of severe, acute anemia on small intestine (SI) and large intestine (LI) anastomoses was evaluated. Thirty-six rabbits underwent segmental resection of the midileum and distal colon. Half underwent preanastomotic removal of 30% of their blood volume with crystalloid resuscitation. At 1 or 2 weeks, the anastomotic bursting pressure (ABP) and histologic grade of white blood cell influx, blood vessel ingrowth, fibroblast proliferation, and collagen deposition were assessed. SI ABP was decreased in anemic rabbits at 2 weeks (190 +/- 6 mm Hg vs. 257 +/- 17 mm Hg). LI ABP was decreased at 1 week in anemic rabbits. In the test rabbits, histologic parameters were altered in both the SI and LI with decreased white blood cell infiltration, attenuated blood vessel ingrowth, and decreased collagen content at both 1 and 2 weeks. Decreased SI fibroblast proliferation was present at 1 week. Acute anemia in the rabbit undergoing intestinal resection decreases the SI ABP at 2 weeks and alters histologic parameters of wound healing in both the SI and LI.

Influence of intraperitoneal phospholipid dosage on adhesion formation and wound healing at different intervals after surgery.

Adjuvant therapy is needed to prevent adhesion formation as a major cause of postoperative morbidity and mortality. The efficacy of phospholipids (PLs) has been proven; however, information on dosage and drug safety are still outstanding. Forty-eight Chinchilla rabbits underwent median laparotomy, abrasion of the peritoneum, jejunal anastomosis, and an electrocautery incision of the liver. The operation was completed by intraperitoneal administration of PLs in two different concentrations (30 mg/kg and 70 mg/kg body weight). In the control group, the abdomen was closed without additional treatment. Adhesion area, anastomotic bursting pressure, tensile strength of the midline incision, and healing of the liver wound were assessed on days 3, 5, 7, and 10, respectively. The mean areas of adhesions in the control group were slightly larger than in the PL groups after 3 days and 5 days. On day 7 and day 10, both PL groups presented with significantly smaller adhesion areas (P<0.05). In all groups, we measured equal anastomotic bursting pressures on the 3rd, 5th, and 10th postoperative days. After 7 days, the mean value of the PL 70-mg group (17.2 kPa) was significantly lower than in the other groups (control 22.1 kPa, PL 30 mg 20.7 kPa; P<0.05). The tensile strengths of the laparotomy wound measured after intervals of 5 days and 7 days were not statistically different. On day 3, it was reduced after 30 mg PL but enhanced after 70 mg PL, whereas 10 days after surgery the strength increased with the PL dosage. The inflammatory reparative response to hepatic injury, jejunal anastomosis, and midline incision was not affected by PLs as assessed by histological analysis. These results prove the efficacy of PLs in adhesion prevention in two concentrations. The findings reveal an unimpeded healing of anastomoses, laparotomy wounds, and liver incisions at different periods after surgery.

Wound healing of intestinal anastomosis after digestive surgery under septic conditions: participation of local interleukin-6 expression.

This study aimed to evaluate the integrity of anastomotic wound healing after digestive surgery under septic conditions and to observe local interleukin-6 (IL-6) expression around the anastomotic segment. Experimental animals were separated into lipopolysaccharide (LPS) and control groups. Each was injected with LPS or normal saline solution into the peritoneal cavity 24 hours before transection and anastomosis of the colon. The anastomotic bursting pressure (ABP) and tissue hydroxyproline concentration (HP) were measured as indicators of wound healing. Immunohistochemical staining for IL-6 was performed on tissue samples obtained from the anastomotic segment, lung, liver, and kidney. The reactive cells were counted by light microscopy. The ABP and HP were significantly lower in the LPS group than the control group 7 days after the surgery. In the LPS group, IL-6 expression around the anastomotic segment was enhanced 1 and 6 hours after surgery but suppressed 24 hours afterward. In contrast, IL-6 expression in lung, liver, and kidney was enhanced in the LPS group 24 hours after surgery but not in the control group. It is suggested that anastomotic wound healing is impaired after digestive tract surgery under septic conditions, and local IL-6 expression participates in wound healing.

New burst test method for comparing strengths of blood vessel repairs

An in vivo system was developed which allows researchers to determine the intraluminal pressures necessary to burst anastomosed blood vessels. Rat femoral arteries underwent standard microsurgical anastomoses and sham surgeries. After 6 min of leak-free blood flow, the vessels were ligated and cannulated with PE 50 tubing. The catheter was tied into position with 6-0 suture, constructing a water-tight balloon of tissue inclusive of the repair site around the tubing, then attached via a "Y" adapter to a pressure transducer with a digital readout and to a saline filled syringe in an infusion pump. The digital readout from the transducer accurately expressed the pressure on the anastomosis. The highest pressure recorded when the anastomosis ruptured was taken to be the anastomotic burst pressure. Mean burst pressure for 9 suture anastomoses was 326 mm mercury. All vessel burst pressures exceeded rat mean systolic pressure; 90% exceeded rat maximum systolic pressure. All sham surgeries failed to burst, even at pressures exceeding 1,500 mm Hg. The burst pressure test clearly provides researchers with a valid quantitative measure for in vivo comparison of the efficacies of various anastomotic techniques.

Novel antiadhesion barrier does not prevent anastomotic healing in a rabbit model.

Intraperitoneal adhesions following surgical procedures cause considerable morbidity. Hyaluronic acid/carboxymethylcellulose (HA/CMC) films have been shown to be effective agents in decreasing adhesion formation. However, when there is an inadvertent leak of bowel contents into the peritoneum due to incomplete anastomosis, adhesion formation about a defect in order to prevent further leakage and to promote healing of the wound is important for the prevention of morbidity and mortality. The purpose of this study was to determine if an antiadhesion film (HA/CMC) impairs these potentially beneficial adhesions to bowel anastomoses, thus predisposing them to enteric leaks with subsequent peritonitis. Sixty-four rabbits were divided in two groups, each undergoing a complete or partial (90% anastomosis to simulate anastomotic leak) large bowel anastomosis. Half of each of the above groups were treated by wrapping a HA/CMC film over the anastomosis and the other half were untreated controls. These two subgroups were then further divided equally and sacrificed at either 7 or 14 days for evaluation of anastomosis integrity and strength. The average anastomotic bursting pressures did not change significantly between those groups treated with HA/CMC when compared to untreated controls at 7 or 14 days or in the complete or partial anastomosis group (Student's t test). Adhesion formation to the anastomosis was not impaired in either group independent of HA/CMC film application. This study suggests that while HA/CMC film has been shown to decrease adhesions in other models, healing of a rabbit colonic anastomosis even in the presence of an anastomotic defect takes place, further suggesting that the stimulus for adhesion formation can overcome the antiadhesion properties of HA/CMC.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of bursting pressure of sutured, stapled and BAR anastomoses

The study was undertaken to compare anastomotic bursting pressure (ABP) of colorectal canine anastomoses using three different anastomotic techniques. Biofragmentable anastomotic ring (BAR), stapled, and sutured colon anastomoses were sequentially placed in each of 48 dogs following division of the colon at three equally spaced sites. Four groups of 12 dogs were sacrificed either on day 0, 3, 7, or 28 and ABP and bursting wall tension were determined. The data revealed that BAR anastomoses have the greatest strength on the day of surgery, sutured anastomoses are the strongest on the third day and all are comparable by the 7th day. Bursting pressures for all groups by day 28 approach normal colonic bursting pressure, with any differences likely to be a reflection of variation in anastomotic fibrosis and other factors.

Fibrin Sealant in High-Risk Colonic Anastomoses

The use of fibrin sealant has been advocated to enhance the healing of high-risk intestinal anastomoses. Colonic anastomoses were performed in 162 rats randomly assigned to four groups: control animals with or without fibrin sealant applied to the anastomosis and steroid-treated animals with or without fibrin sealant. At five days postoperatively, the use of steroids alone significantly reduced the anastomotic bursting pressure (ABP) and enhanced abscess and adhesion formation. The addition of fibrin sealant to the anastomosis in steroid-treated animals did not improve ABP and, in fact, further increased abscess formation. In control animals, the use of fibrin sealant also reduced ABP and enhanced abscess and adhesion formation. By ten days, there was no difference in ABP among the groups, and the rate of abscess formation was reduced in all groups. These findings indicated that short-term treatment with steroids delayed colonic anastomotic healing. Fibrin sealant did not enhance the integrity of these high-risk anastomoses. The present data do not support the use of fibrin sealant in high-risk colonic anastomoses.