Effect of early postoperative feeding on the healing of colonic anastomoses in the presence of intra-abdominal sepsis in rats

The Safety and Efficacy of Early Enteral Nutrition After Paediatric Enterostomy Closure - The EPOC Study

INTRODUCTION

Keeping children nil by mouth until return of bowel function after intestinal anastomosis surgery is said to reduce complications. Fasting may extend up to five days, risking malnourishment and usage of parenteral nutrition. This study aims to establish the efficacy and safety of early enteral nutrition in children undergoing intestinal stoma closure.

METHODOLOGY

A retrospective cohort study of children aged three months to 16 years who underwent an intestinal stoma closure between 1/1/2019 and 31/12/2021 at two tertiary paediatric hospitals was undertaken. Children fed clear fluids within 24 h (EEN) were compared to those commencing feeds later (LEN). The primary outcome was length of post-operative stay (LOS) and secondary outcomes included: time to feeds; time to stool; and complications.

RESULTS

Of the 129 children that underwent a stoma closure, 69 met inclusion criteria: 35 (51 %) in the LEN group and 34 (49 %) in the EEN group. Children in the EEN group had a significantly shorter LOS (92.6 h vs 121.7 h, p = 0.0045). Early feeding was also associated with a significantly decreased time to free fluids (p < 0.001) and full enteral intake (p = 0.007). There was no significant intergroup difference in complications.

CONCLUSION

Commencing feeding within 24 h of stoma closure is efficacious and safe, with clear reductions in LOS, time to full feeds and time to stool, and no increase in complications. Further research is required to extrapolate these findings to other populations.

LEVEL OF EVIDENCE

III.

Ketorolac Administration After Colorectal Surgery Increases Anastomotic Leak Rate: A Meta-Analysis and Systematic Review

Objective

This meta-analysis aimed to evaluate whether ketorolac administration is associated with an increased anastomotic leak rate after colorectal surgery.

Methods

The literature was searched using the Web of Science, Embase, and PubMed databases, and the search ended on May 31, 2020. The Newcastle–Ottawa Scale was used to assess methodological quality. Statistical heterogeneity was assessed using the Chi-square Q test and I² statistics. Subgroup analysis was performed, and Egger's test was used to assess publication bias.

Results

This meta-analysis included seven studies with 400,822 patients. Our results demonstrated that ketorolac administration after surgery increases the risk of anastomotic leak [OR = 1.41, 95% CI: 0.81–2.49, Z = 1.21, P = 0.23]. Low heterogeneity was observed across these studies (I² = 0%, P = 0.51). The results of subgroup analysis showed that the use of ketorolac in case–control and retrospective cohort studies significantly increased the risk of anastomotic leak (P < 0.05). Furthermore, the subgroup analysis revealed that ketorolac use increased anastomotic leak rate in patients in the United States and Canada, and ketorolac plus morphine use did not increase anastomotic leak rate in Taiwanese patients (P < 0.05). No significant publication bias was observed (P = 0.126). Moreover, the analysis of risk factors related to anastomotic leak rate indicated that the total use of ketorolac did not increase the risk of anastomotic leak similar to the control group (P > 0.05).

Conclusion

The meta-analysis indicates that the use of ketorolac increases the risk of anastomotic leak after colorectal surgery.

Systematic Review Registration

PROSPERO, identifier CRD42020195724.

Early enteral feeding after pediatric abdominal surgery: A systematic review of the literature

INTRODUCTION

Traditionally enteral nutrition has been delayed following abdominal surgery in children, to prevent complications. However, recent evidence in the adult literature refutes the supposed benefits of fasting and suggests decreased complications with early enteral nutrition (EEN). This review aimed to compile the evidence for EEN in children in this setting.

METHODS

Databases Pubmed, EmBase, Medline and reference lists were searched for articles containing relevant search terms according to PRISMA guidelines. First and second authors reviewed abstracts. Studies containing patients less than 18 years undergoing abdominal surgery, with feeding initiated earlier than standard practice, were included. Studies including pyloromyotomy were excluded. Primary outcome was length of stay (LOS). Secondary outcomes included time to full enteral nutrition, time to stool and postoperative complications.

RESULTS

Fourteen articles met inclusion criteria - five on neonatal abdominal surgery, three on gastrostomy formation and six on intestinal anastomoses. There were three randomized control trials (RCTs), five cohort studies, four historical control trials, one nonrandomized trial and one case series. Nine studies showed a decreased LOS with EEN. Most studies which reported time to full enteral nutrition showed improvement with EEN; however, time to stool was similar in most studies. Postoperative complications were either decreased or not statistically different in EEN groups in all studies.

CONCLUSION

Studies to date in a limited number of procedures suggest EEN appears safe and effective in children undergoing abdominal surgery. Although robust evidence is lacking, there are clear benefits in LOS and time to full feeds, and no increase in complications.

LEVEL OF EVIDENCE

IV.

Role of Nutrition in Prevention of Neonatal Spontaneous Intestinal Perforation and Its Complications: A Systematic Review

Background: Spontaneous intestinal perforation (SIP) is a devastating complication of prematurity, and extremely low birthweight (ELBW < 1000 g) infants born prior to 28 weeks are at highest risk. The role of nutrition and feeding practices in prevention and complications of SIP is unclear. The purpose of this review is to compile evidence to support early nutrition initiation in infants at risk for and after surgery for SIP. Methods: A search of PubMed, EMBASE and Medline was performed using relevant search terms according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Abstracts and full texts were reviewed by co-first authors. Studies with infants diagnosed with SIP that included information on nutrition/feeding practices prior to SIP and post-operatively were included. Primary outcome was time to first feed. Secondary outcomes were incidence of SIP, time to full enteral feeds, duration of parenteral nutrition, length of stay, neurodevelopmental outcomes and mortality. Results: Nineteen articles met inclusion criteria—nine studies included feeding/nutrition data prior to SIP and ten studies included data on post-operative nutrition. Two case series, one cohort study and sixteen historical control studies were included. Three studies showed reduced incidence of SIP with initiation of enteral nutrition in the first three days of life. Two studies showed reduced mortality and neurodevelopmental impairment in infants with early feeding. Conclusions: Available data suggest that early enteral nutrition in ELBW infants reduces incidence of SIP without increased mortality.

Comparison of the Effects of Neostigmine and Sugammadex on Colonic Anastomotic Strength in Rats

BACKGROUND

After colorectal surgery, anastomotic leakage is a major cause of mortality and morbidity. There are many factors affecting anastomotic leakage. It is known that agents such as neostigmine that is used to reverse neuromuscular blockade have certain effects on anastomosis. In our study, in which we planned to test this hypothesis, we aimed to compare the possible effects of different doses of sugammadex and neostigmine on colon anastomosis strength in a colonic resection anastomosis model in rats.

MATERIALS AND METHODS

Forty adult Wistar albino male rats were divided into five groups as control (group C), Sugammadex 16 mg/kg (group SL), sugammadex 96 mg/kg (group SH), neostigmine 0.3 μmol/kg (group NL), and neostigmine 1.5 μmol/kg (group NH). The transverse colons of all rats were resected, and colonic anastomosis was performed. Appropriate drug doses according to the groups were given on the postoperative seventh day, and tissue hydroxyproline (TH) level and anastomotic bursting pressure were measured.

RESULTS

Anastomotic bursting pressure values were statistically significantly different between the groups (P = 0.001). The bursting pressure in group SH was significantly higher compared with group C, group NL, and group NH. The hydroxyproline values were statistically significantly different between the groups (P = 0.015). According to the post hoc test results, the difference was between group SH and group C (P = 0.007). There were no significant differences between the other groups (P > 0.05). There was no significant difference in terms of intra-abdominal adhesion rates between the groups.

CONCLUSIONS

In our study, we found that low and high doses of neostigmine had no variable effect on anastomosis, but high dose of sugammadex (96 mg/kg) had an increasing effect on intestinal anastomosis strength.

Effect of Early vs Late Start of Oral Intake on Anastomotic Leakage Following Elective Lower Intestinal Surgery: A Systematic Review

BACKGROUND

Experimental and clinical studies have demonstrated a beneficial effect of early enteral nutrition (EN) on anastomotic leakage following colorectal surgery. Early oral intake is a common form of early EN with various clinical benefits, but the effect on anastomotic leakage is unclear. This systematic review investigates the effect of early vs late start of oral intake on anastomotic leakage following lower intestinal surgery.

METHODS

A systematic literature search was performed using the PubMed, Embase, Medline, and Cochrane databases. Randomized controlled trials were included that compared early (within 24 hours) vs late start of oral intake following elective surgery of the small bowel, colon, or rectum. Meta-analysis was performed for anastomotic leakage, overall complications, length of stay, and mortality. Sensitivity analysis was performed in which studies of inferior methodological quality were excluded.

RESULTS

Nine studies including 879 patients met eligibility criteria. Early start of oral intake significantly reduced overall complications (odds ratio [OR], 0.65; 95% confidence interval [CI], 0.46-0.93; P = .02), length of stay (mean difference, -0.89; 95% CI, -1.22 to -0.57; P < .001), and anastomotic leakage (OR, 0.40; 95% CI, 0.17-0.95; P = .04) compared with late start of oral intake. However, in the sensitivity analysis only the overall reduction of length of stay remained significant.

CONCLUSION

The effect of early oral intake on anastomotic leakage is unclear as existing studies are heterogeneous and at risk of bias. High-quality studies are needed to study the potential benefit of EN on anastomotic healing.

Nutrients and Wound Healing: Still Searching for the Magic Bullet

Clinicians in nearly all practice areas are confronted with the challenges associated with delayed and impaired wound healing. Although nutrition plays a critical role in the healing process, controversy exists regarding the optimal nutrition regimen. This article reviews literature related to nutrition interventions that facilitate wound healing. The limitations of the research that forms the scientific basis of many nutrition recommendations are also examined. The limited availability of rigorously performed clinical studies to develop evidence-based guidelines for nutrition support in wound care emphasizes the need for further research and underscores the importance of individualizing the nutrition care plan for each patient.

Ketorolac Use and Postoperative Complications in Gastrointestinal Surgery

OBJECTIVE

To study the association between ketorolac use and postoperative complications.

BACKGROUND

Nonsteroidal anti-inflammatory drugs may impair wound healing and increase the risk of anastomotic leak in colon surgery. Studies to date have been limited by sample size, inability to identify confounding, and a focus limited to colon surgery.

METHODS

Ketorolac use, reinterventions, emergency department (ED) visits, and readmissions in adults (≥ 18 years) undergoing gastrointestinal (GI) operations was assessed in a nationwide cohort using the MarketScan Database (2008-2012).

RESULTS

Among 398,752 patients (median age 52, 45% male), 55% underwent colorectal surgery, whereas 45% had noncolorectal GI surgery. Five percent of patients received ketorolac. Adjusting for demographic characteristics, comorbidities, surgery type/indication, and preoperative medications, patients receiving ketorolac had higher odds of reintervention (odds ratio [OR] 1.20, 95% confidence interval [CI] 1.08-1.32), ED visit (OR 1.44, 95% CI 1.37-1.51), and readmission within 30 days (OR 1.11, 95% CI 1.05-1.18) compared to those who did not receive ketorolac. Ketorolac use was associated with readmissions related to anastomotic complications (OR 1.20, 95% CI 1.06-1.36). Evaluating only admissions with ≤ 3 days duration to exclude cases where ketorolac might have been used for complication-related pain relief, the odds of complications associated with ketorolac were even greater.

CONCLUSIONS

Use of intravenous ketorolac was associated with greater odds of reintervention, ED visit, and readmission in both colorectal and noncolorectal GI surgery. Given this confirmatory evaluation of other reports of a negative association and the large size of this cohort, clinicians should exercise caution when using ketorolac in patients undergoing GI surgery.

Is combined therapy more effective than growth hormone or hyperbaric oxygen alone in the healing of left ischemic and non-ischemic colonic anastomoses?

OBJECTIVE

Our aim was to investigate the effects of growth hormone (GH), hyperbaric oxygen and combined therapy on normal and ischemic colonic anastomoses in rats.

METHODS

Eighty male Wistar rats were divided into eight groups (n = 10). In the first four groups, non-ischemic colonic anastomosis was performed, whereas in the remaining four groups, ischemic colonic anastomosis was performed. In groups 5, 6, 7, and 8, colonic ischemia was established by ligating 2 cm of the mesocolon on either side of the anastomosis. The control groups (1 and 5) received no treatment. Hyperbaric oxygen therapy was initiated immediately after surgery and continued for 4 days in groups 3 and 4. Groups 2 and 6 received recombinant human growth hormone, whereas groups 4 and 8 received GH and hyperbaric oxygen treatment. Relaparotomy was performed on postoperative day 4, and a perianastomotic colon segment 2 cm in length was excised for the detection of biochemical and mechanical parameters of anastomotic healing and histopathological evaluation.

RESULTS

Combined treatment with hyperbaric oxygen and GH increased the mean bursting pressure values in all of the groups, and a statistically significant increase was noted in the ischemic groups compared to the controls (p<0.05). This improvement was more evident in the ischemic and normal groups treated with combined therapy. In addition, a histopathological evaluation of anastomotic neovascularization and collagen deposition showed significant differences among the groups.

CONCLUSIONS

Combined treatment with recombinant human growth hormone and hyperbaric oxygen resulted in a favorable therapeutic effect on the healing of ischemic colonic anastomoses.

The effects of early and late feeding on healing of esophageal anastomoses: an experimental study

OBJECTIVE

To investigate the effects of postoperative late and early feeding on the healing of experimental esophageal anastomosis (EA).

METHODS

Twelve New Zealand rabbits were divided equally into 2 groups: late feeding (LF) and early feeding (EF). A 1-cm-length of the cervical esophagus was resected through a cervical incision, and then anastomosis was performed. The LF group was fed parenterally for 6 days and orally (per oral route) after esophagography on postoperative day 7 as long as there was no esophageal leakage. The EF group was fed orally (per oral route) 24h after esophageal repairs (ERs), and esophagography was carried out on postoperative day 7 to check the ERs. The rabbits were sacrificed to evaluate bursting pressure (BP), diameter of the esophageal lumen (DOTEL), tissue hydroxyproline (HP), and wound healing scores (WHSs) in the anastomosis lines 8 weeks later.

RESULTS

In the LF group, BP and DOTEL were significantly lower than they were in the EF group, and HP was significantly higher than it was in the EF group. WHSs in the LF group were not higher than they were in the EFgroup.

CONCLUSIONS

Early feeding is superior after EA as shown by increased DOTEL and BP levels, but causes decreased HP levels.

Intra-abdominal healing: gastrointestinal tract and adhesions

The abdominal cavity represents one of the most active areas of surgical activity. Surgical procedures involving the gastrointestinal (GI) tract are among the most common procedures performed today. Healing of the GI tract after removal of a segment of bowel and healing of the peritoneal surfaces with subsequent adhesion formation remain vexing clinical problems. Interventions to modify both the responses are myriad, yet a full understanding of the pathophysiology of these responses remains elusive. Different aspects of GI and peritoneal healing, with associated factors, are discussed in this article.

Effects of the histamine H2 receptor antagonist famotidine on the healing of colonic anastomosis in rats

BACKGROUND

Failure of anastomotic healing is one of the major complications in colorectal surgery. Because histamine plays an important role in immune and inflammatory reactions, we demonstrate the effects of famotidine on the healing of colonic anastomosis in rats.

METHODS

Twenty-eight Sprague-Dawley rats were used in the study. Excision and end-to-end anastomosis was performed in the distal colon of the rat. The Famotidine Group received 2 mg/kg/day famotidine; the Control Group received the same amount of saline. Bursting pressure of anastomoses and hydroxyproline content of perianastomotic tissues were evaluated on the third and seventh days following surgery.

RESULTS

Bursting pressures and hydroxyproline contents for the Famotidine Group were significantly lower than the equivalent parameters for the Control Group on both the third and seventh days post-surgery.

CONCLUSIONS

According to our findings, famotidine exerts detrimental effects on the anastomotic bursting pressure and hydroxyproline content of perianastomotic tissues in the colon of rats.

Early glutamine-enriched enteral feeding facilitates colonic anastomosis healing: light microscopic and immunohistochemical evaluation

Problems related to colonic anastomosis healing constitute the major morbidity in colorectal surgery. Patients without appropriate nutritional support are at higher risk of postsurgical complications, mainly due to reduced wound healing. Therefore, we investigated the effect of early and late postoperative total enteral nutrition (TEN) and glutamine addition on colon anastomosis healing using light microscopy and immunohistochemistry (IGF-I immunolabelling). In this study, 40 Wistar-albino rats underwent distal left colonic transection and anastomosis. The rats were then divided into four groups given different diets: delayed total enteral nutrition (dTEN; beginning 3 days postoperatively), delayed TEN with added glutamine (dTEN+Glutamine), early TEN (eTEN; beginning within 6h postoperatively), and early TEN with added glutamine (eTEN+Glutamine). Colon segments, including the anastomosis, were excised 7 days postoperatively and evaluated histopathologically for inflammation, mucosal healing, submucosal-muscular layer repair, the amounts of necrosis and vascularisation and immunohistochemically for IGF-I labelling. The inflammation and necrosis scores in the dTEN and dTEN+Glutamine groups were significantly greater than in the eTEN and eTEN+Glutamine groups. The IGF-I immunoreactivity increased in the eTEN, eTEN+Glutamine, and dTEN+Glutamine groups compared to dTEN (p<0.05). We concluded that early TEN and glutamine enrichment in the postoperative period improve anastomosis healing via IGF-I.

Advances in Surgical Nutrition

Dr. Stanley Dudrick invented total parenteral nutrition in 1968, providing a desperately needed therapy to those patients who could not eat. It has since saved thousands of patients worldwide. Nutrition interventions (NI) in surgical/trauma and critically ill patients have evolved dramatically during the last 20 years from a supportive therapy to a clear therapeutic role. Like any other form of therapy, NI will benefit patients when adequately indicated and prescribed. NI, however, may cause significant side effects and harm when poorly ordered. This article reviews the indications for the prescription of the different forms of NI available to the clinician caring for the surgical patient.

Effects of diclofenac sodium on bursting pressures of anastomoses and hydroxyproline contents of perianastomotic tissues in a laboratory study

BACKGROUND

Non-steroidal anti-inflammatory drugs are commonly used to relieve postoperative pain. Diclofenac sodium is a non-steroidal anti-inflammatory drug used as an analgesic during the postoperative period. Diclofenac sodium has powerful anti-inflammatory actions. As anti-inflammatory action may interfere with wound healing, we have studied the effects of diclofenac sodium on the healing of colonic anastomosis in rats.

METHODS

Thirty-six Sprague-Dawley rats were used. Resection and anastomosis was performed on the distal colon of rats. The diclofenac group of rats received 4mg/kg/day diclofenac sodium intramuscularly. The control group received 0.1mL/day 0.9% NaCl intramuscularly. Anastomoses were evaluated with bursting pressure of the anastomoses and hydroxyproline level of the perianastomotic tissues on the third and seventh postoperative days. The Mann-Whitney U-test was used for statistical analysis.

RESULTS

Three rats from each group died because of septic complications due to anastomotic leaks. Bursting pressures of the diclofenac group of rats (3rd day: 40.12+/-6.72mmHg; 7th day: 172.02+/-30.74mmHg) were lower than controls (3rd day: 54.13+/-8.11mmHg; 7th day: 206.00+/-27.14mmHg) both on the third and seventh days. Mean hydroxyproline contents of the perianastomotic tissues of diclofenac-treated rats (3rd day: 1.97+/-0.17mug/mg tissue; 7th day: 3.61+/-0.32mug/mg tissue) were lower than controls (3rd day: 2.16+/-0.12mug/mg tissue; 7th day: 4.95+/-0.64mug/mg tissue) both on the 3rd and 7th days, similar to bursting pressures.

CONCLUSIONS

Diclofenac sodium had a negative effect on bursting pressures of the colonic anastomoses and hydroxyproline contents of perianastomotic tissues of rats in our study. Anastomotic leak rates were not affected. The effects of diclofenac sodium should be studied in detail.

Improvement of colonic healing by preoperative rectal irrigation with short-chain fatty acids in rats given radiotherapy

BACKGROUND

We investigated the effect of preoperative rectal irrigation with short-chain fatty acids on irradiated colonic anastomosis in rats.

METHODS

Sixty male Wistar rats were divided into four groups. Group I (control group, n = 15) underwent left colon resection and primary anastomosis. Group II (Short-chain fatty acids pretreatment group, n = 15) had short-chain fatty acids rectal irrigation for five days preoperatively. Group III (preoperative radiotherapy group, n = 15) underwent irradiation to the whole pelvis eight and four days before the operation, for a total dose of 20 Gy. Group IV (preoperative radiotherapy group + short-chain fatty acids pretreatment group, n = 15) had rectal irrigation with short-chain fatty acids for five days after the second irradiation. Within each group, animals were anesthetized to assess the clinical, mechanical, histologic, and biochemical parameters of anastomotic healing on either the third or seventh postoperative days.

RESULTS

The mean bursting pressure was significantly low in Group III on Day 3 and was significantly high in Group IV on Day 7 (P = 0.001, P = 0.021). The burst occurred at the anastomoses in all animals tested on the third postoperative day, and outside of the anastomoses in all animals tested on the seventh postoperative day. The histologic parameters of anastomotic healing, such as epithelial regeneration and formation of granulation tissue, were significantly improved by use of preoperative rectal irrigation with short-chain fatty acids on Day 7. The amount of total and salt-soluble collagen concentrations significantly increased in Group IV compared with the control group on Day 3 (P = 0.008, P = 0.004).

CONCLUSION

Some mechanical and histologic aspects of colonic anastomotic healing can be adversely affected by preoperative radiotherapy, but rectal irrigation with short-chain fatty acids may improve anastomotic healing.

Early enteral feeding after closure of colostomy in pediatric patients

BACKGROUND/PURPOSE

The aim of this study was to determine the benefits and adverse effects of protocolized early postoperative enteral feeding in pediatric patients undergoing a closure of colostomy.

METHODS

Pediatric patients, completely treated for anorectal malformation, who underwent a closure of colostomy during September 2000 and May 2002 received early postoperative feeding according to the authors' protocol (EF group). Retrospective data of consecutive patients operated on from March 1998 to August 2000 who received traditional feeding practice were used as a control (TF group). The protocol began with a small volume of formula or breast feeding within the first postoperative day. Volume allowance was advanced every 4 hours up to the daily maintenance volume. Full feeding was defined as when the patient was able to tolerate at least 80% of daily maintenance volume. TF group received nothing by mouth until documentation of bowel function. The groups were compared with regard to postoperative stay, postoperative hour of full feeding, first bowel movement, and adverse effects. Statistical analyses were performed with chi2 test, Student's t test, and Mann-Whitney U test.

RESULTS

There were 34 and 30 patients in EF and TF groups, respectively. Median age of the patients was 13 months, and median weight was 8.39 kg. Except for the associated anomalies, which were found more in the EF group, there were no differences in the demographic characteristics of the 2 groups. On average, feeding was initiated at 19.7 (16 to 24) hours in the EF group and 51.7 (18 to 92) hours in the TF group (P <.01). Median full feeding hours were 45.5 and 70.5 hours in the EF and TF group, respectively (P <.01). First bowel movement in the EF group was recorded at the average of 4.14 postoperative nurse shifts, compared with 5.96 shifts in the TF group (P <.01). Postoperative stay was significantly reduced from the average of 6.1 days to 4.5 days (P <.01). The overall hospital expenses were not significantly different between the 2 groups. (203.95 dollars US in TF group and 198.50 dollars US in EF group; P =.75) There was 1 vomiting case in the EF group that was temporary and resolved spontaneously. Septic complications were noted in 8 patients in the EF group and 6 patients in the TF group (P =.27). The majority were uncomplicated urinary tract infections.

CONCLUSIONS

Early feeding after a closure of colostomy in pediatric patients stimulated early bowel movement and reduced hospital stay with no increased adverse effects.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Repair of full-thickness bowel injury

OBJECTIVE

Colon surgery is more and more often performed in complex situations such as after trauma, under immunosuppression, or in the elderly. Even under optimal conditions, anastomosis fails in certain situations. The objective of this study was to demonstrate the normal phases of bowel healing and to review the local and systemic factors affecting healing with special attention to critical care variables such as major surgery, acute hemorrhage, and infections.

DATA SOURCE

MEDLINE cited and/or published articles.

DESIGN

Review analysis.

RESULTS

Colon healing is a structured cascade of different phases that can be affected by a multitude of local (infection, ischemia) and systemic (diabetes, malnutrition, anemia, hypothermia, trauma) factors. The normal phases of repair, the resulting bursting pressure as an experimental index of healing, and the available published data on local and systemic factors affecting healing are summarized.

CONCLUSION

Several local and systemic factors negatively affect bowel healing; there is still a small portion of patients who fail to heal, suggesting that intrinsic factors need to be analyzed.

Tacrolimus enhances colon anastomotic healing in rats

Tacrolimus inhibits T-cell function and neutrophil chemotaxis during inflammation. We hypothesized that tacrolimus would enhance healing of a rat colon anastomosis by reducing the inflammatory response. Fifty-five male Sprague Dawley rats, 230-260 g body weight, underwent identical surgical manipulation consisting of a single-layer, inverted colon anastomosis and the implantation of osmotic pumps subcutaneously in the left flank area. The animals were randomly assigned to receive tacrolimus, at a dose of 0.01, 0.1, or 1.0 mg/kg/day, or only the control solvent solution. The animals were euthanized 4 days after surgery. Colon-bursting pressure (mmHg), anastomotic collagen content ( micro g hydroxyproline/mg wet tissue), and anastomotic type IV collagenase activity (mU/mg protein) were measured. Tacrolimus significantly increased colon-bursting pressure at all doses used (146 +/- 9, 158 +/- 10, 151 +/- 6 mmHg; 0.01, 0.1, and 1.0 mg/kg/day, respectively) vs. control (119 +/- 7 mmHg, p < 0.01). There was no effect on collagen accumulation except at a dose of 0.01 mg/kg/day, which significantly decreased anastomotic collagen content (p < 0.05). Tacrolimus at a dose of 0.01 mg/kg/day increased anastomotic collagenase activity, which was not changed by treatment with the higher doses. Microscopic examination revealed the preservation of the multilayered structure, including the mucosal muscle, a thickened submucosa, and the proper muscle of the anastomotic site in the tacrolimus-treated groups. These data suggest that tacrolimus enhances wound strength during acute anastomotic healing despite a reduction in collagen content.

Perioperative matrix metalloproteinase inhibition therapy does not impair wound or anastomotic healing

Matrix metalloproteinases (MMPs) catalyze the degradation of collagen and extracellular matrix. They play a role in pathologic states including malignancy, in which they facilitate invasion and metastasis. MMP inhibition has been shown to block neoplastic invasion and improve survival in animal models of malignancy. Concern about the effects of MMP inhibitors on wound and anastomotic healing may limit their potential use in the perioperative period to prevent local and systemic showering of cancer cells from surgical manipulation. We sought to assess the safety of perioperative administration of an MMP inhibitor (BB-94) with respect to skin and bowel healing in a rat model. Absorption of BB-94 was confirmed through high-pressure liquid chromatography and mass spectroscopy of sera from treated animals. Bowel bursting pressure in all animals increased almost 10-fold between 4 and 14 days. Two-way analysis of variance showed no significant difference in bowel bursting pressure between control and treatment animals over time. There was a significant increase in the collagen content of skin specimens of all animals combined between 4 and 28 days. Similarly, all animals showed an increase in bowel collagen between 4 and 28 days. There was no significant difference in skin or bowel collagen concentrations between control and treatment animals over time. Perioperative treatment with MMP inhibition does not impair wound or enteric healing in a rat model of laparotomy and small bowel resection. MMP inhibitors are safe for use as adjuvant therapy after resection for cancer.

Early postoperative enteral feeding increases anastomotic strength in a peritonitis model

BACKGROUND

Tumor necrosis factor alpha (TNF-alpha) has been shown to decrease collagen synthesis and increase collagenase activity leading to impaired wound healing. Our hypothesis was that immediate postoperative feeding would decrease TNF-alpha, therefore increasing anastomotic healing in a peritonitis model.

METHODS

Twelve Sprague-Dawley rats underwent cecal ligation and puncture to induce peritonitis. Six hours after induction of peritonitis an ileocecectomy and ileocolostomy was performed. Group 1 animals (n = 6) had immediate access to food and water, whereas group 2 (n = 6) had free access to water only. At 48 hours, weight loss, nitrogen loss, anastamotic bursting strength (ABS), TNF-alpha, interleukin-6 (IL-6), and IL-10 were measured.

RESULTS

Weight loss was similar in the two groups. Group 1 rats had a significantly lower mean TNF-alpha level (17.3 +/- 10 versus 17.3 +/- 10 mcg/Dl, P = 0.05). ABS was also significantly higher in group 1 rats when compared with group 2 rats (81 +/- 34 versus 39 +/- 13 mm HG, P = 0.03).

CONCLUSIONS

These data suggest that immediate postoperative feeding results in a beneficial change in the cytokine profile.

Effect of matrix metalloproteinase inhibition on colonic anastomotic healing in rats

Wound strength depends on the balance between collagen synthesis and degradation; however, the role of collagen breakdown in wound healing is still not well understood. We investigated the role of matrix metalloproteinases in wound healing by using BE16627B, a matrix metalloproteinase inhibitor. Identical surgical procedures consisting of a colonic anastomosis (single-layer, inverted) and implantation of an osmotic pump in the back were performed in male Sprague-Dawley rats weighing 270 to 290 grams. The animals were randomly assigned to receive either BE16627B (n = 10) dissolved in dimethylsulfoxide and diluted with ethylene glycol at a dosage of 2.4 mg/rat/day for 3 days or the vehicle solution alone (n = 11). The solutions were administered through the surgically implanted osmotic pumps. The animals were killed 4 days after surgery, and the colonic bursting pressure (mm Hg) and hydroxyproline concentration (microg/mg wet tissue, index of collagen) were measured. The administration of BE16627B enhanced colonic anastomotic healing, as measured by the increase in the colonic bursting pressure (160 +/- 12 vs. 125 +/- 7 mm Hg; P < 0.05) and the increase in the soluble fraction of collagen (0.27 +/- 0.01 vs. 0.21 +/- 0.01 microg/mg wet tissue; P < 0.01) in the anastomosis. Histologic examination of the tissue revealed that the use of BE16627B resulted in the preservation of the multilayered colonic structure and increased the network of collagen between both ends of the colon in the thickening submucosal layer. These findings demonstrate that the inhibition of matrix metalloproteinase activity influences colonic anastomotic healing, indicating a potential mechanism for enhancing anastomotic healing.