Prevention of postoperative peritoneal adhesions: a review of the literature

The Preventive Effect of Dexmedetomidine Against Postoperative Intra-abdominal Adhesions in Rats

This study aimed to determine the possible preventive effects of dexmedetomidine on postoperative intra-abdominal adhesions. Dexmedetomidine is a highly selective and potent α2 adrenergic agonist with sedative, analgesic, anxiolytic, sympatholytic, hemodynamic, and diuretic properties. In recent years, investigations have shown that dexmedetomidine possesses secondary antioxidant and also anti-inflammatory effects. Thirty Wistar albino male rats were randomized and divided into 3 groups of 10 animals each: group 1, sham-operated; group 2, cecal abrasion + peritoneal dissection; group 3, cecal abrasion + peritoneal dissection followed by daily intravenous injection of 10 μg/kg dexmedetomidine for 10 days. The animals were killed on postoperative day 21. Blood and cecal samples were taken for biochemical and histopathologic evaluation. In this study, biochemical and pathologic parameters were significantly better in the cecal abrasion + peritoneal dissection + dexmedetomidine group when compared with the cecal abrasion + peritoneal dissection group. Tissue malondialdehyde, myeloperoxidase, total sulfhydryl, and catalase were found to be significantly different between the cecal abrasion/peritoneal dissection + dexmedetomidine and the cecal abrasion/peritoneal dissection groups. Plasma malondialdehyde and total sulfhydryl values were also statistically different between these groups (P < 0.05). Statistical analyses of mean pathologic scores showed that the histopathologic damage in the cecal abrasion/peritoneal dissection + dexmedetomidine group was significantly less than the damage in the control group (P < 0.05 for all pathologic parameters). The results of this study show that dexmedetomidine had a significant preventive effect on postoperative intra-abdominal adhesions. We concluded that these effects might be due to antioxidant and anti-inflammatory activities.

Small bowel obstruction in the virgin abdomen: time to challenge surgical dogma with evidence

BACKGROUND

Although adhesions account for more than 70% of small bowel obstruction (SBO), they are thought to be less likely aetiologies in patients without previous abdominal surgery. Expedient surgery has historically been advocated as prudent management in these patients. Emerging evidence appears to challenge such a dogmatic approach.

METHODS

A retrospective analysis was performed in all SBO patients with a virgin abdomen admitted between January 2012 and August 2014. Patients with obstruction secondary to abdominal wall hernias were excluded. Patient demographics, clinical presentation, management strategy and pathology involved were reviewed.

RESULTS

A total of 72 patients were included in the study. The majority of patients were males (66.7%), with a median age of 58 years (range: 23-101). Abdominal pain (97%) and vomiting (86%) were the most common presentations while abdominal distention (60%) and constipation (25%) were reported less frequently. Adhesions accounted for the underlying cause in 44 (62%) patients. Other aetiologies included gallstone ileus (n = 5), phytobezoar (n = 5), intussusception (n = 4), internal herniation (n = 4), newly diagnosed small bowel tumour (n = 3), mesenteric volvulus (n = 3), stricture (n = 3) and Meckel's diverticulum (n = 1). Twenty-nine (40%) patients were successfully managed conservatively while the remaining 43 (60%) underwent surgery. The intraoperative findings were in concordance with the preoperative computed tomography scan in 76% of cases.

CONCLUSION

Adhesions remain prevalent despite the absence of previous abdominal surgery. Non-operative management is feasible for SBO in a virgin abdomen. Computed tomography scan can be a useful adjunct in discerning patients who may be treated non-operatively by elucidating the underlying cause of obstruction.

Comparison of the effects of Mitomycin-C and sodium hyaluronate/carboxymethylcellulose [NH/CMC] (Seprafilm) on abdominal adhesions

Introduction

Intra-abdominal adhesions (IA) may occur after abdominal surgery and also may lead to complications such as infertility, intestinal obstruction and chronic pain. The aim of this study was to compare the effects of Mitomycin-C (MM-C) and sodium hyaluronate/carboxymethylcellulose [NH/CMC] on abdominal adhesions in a cecal abrasion model and to investigate the toxicity of MM-C on complete blood count (CBC) and bone marrow analyses.

Methods

The study comprised forty rats in four groups (Control, Sham, Cecal abrasion + MM-C, and Cecal abrasion + NH/CMC). On postoperative day 21, all rats except for the control (CBC + femur resection) group, were sacrificed. Macroscopical and histopathological evaluations of abdominal adhesions were performed. In order to elucidate the side effects of MM-C; CBC analyses and femur resections were performed to examine bone marrow cellularity.

Results

CBC analyses and bone marrow cellularity assessment revealed no statistically significant differences between MM-C, NH/CMC and control groups. No significant differences in inflammation scores were observed between the groups. The MM-C group had significantly lower fibrosis scores compared to the NH/CMC and sham groups. Although the adhesion scores were lower in the MM-C group, the differences were not statistically significant.

Conclusion

Despite its potential for systemic toxicity, MM-C may show some anti-fibrosis and anti-adhesive effects. MM-C is a promising agent for the prevention of IAs, and as such, further trials are warranted to study efficacy.

Adhesions and Healing of Intestinal Anastomoses

Background. Postoperative adhesions are the result of aberrant peritoneal healing. As they are the leading cause of postoperative bowel obstruction, anti-adherence barriers are advocated for their prevention. This study looks into the effect of these biomaterials on the healing of intestinal anastomoses. Materials and Methods. Thirty-three New Zealand White rabbits underwent laparotomy, transection of the terminal ileum, and creation of an end-to-end anastomosis. Animals were randomized into 3 groups: the Control group (n = 11); the Icodextrin group, receiving icodextrin 4% intraperitonealy (n = 11); and the HA/CMC group, having the anastomosis wrapped with a hyaluronic acid/carboxymethylcellulose film (n = 11). All animals were sacrificed on the seventh postoperative day. Macroscopic adhesions were graded and anastomotic strength was tested by the burst pressure. Histological healing was assessed in a semiquantitative way for the presence of ulceration, reepithelization, granulation tissue, inflammation, eosinophilic infiltration, serosal inflammation, and microscopic adhesions. Univariate and multivariate analysis was used. Results are given as medians with interquartile range. Results. The median adhesion scores were the following: Control 1 (0-3), Icodextrin 0 (0-1), HA/CMC 0 (0-0), P = .017. The burst pressure did not differ between the groups; however, all except one bowel segments tested burst away from the anastomosis. The macroscopic and histological anastomotic healing was comparable in all 3 groups. A poor histological anastomotic healing score was associated with a higher adhesion grade (odds ratio = 1.92; 95% confidence interval = 1.06-3.47; P = .032). Conclusion. Adhesion formation was inhibited by the materials tested without direct detrimental effects on anastomotic healing. Poor anastomotic healing provokes adhesions even in the presence of anti-adhesion barriers.

Role of icodextrin in the prevention of small bowel obstruction. Safety randomized patients control of the first 300 in the ADEPT trial

AIM

Adhesions are the most common cause of small bowel obstruction (SBO). The costs of hospitalization and surgery for SBO are substantial for the health-care system. The adhesion-limiting potential of icodextrin has been shown in patients undergoing surgery for gynaecological diseases. A randomized, multicentre trial in colorectal cancer surgery started in 2009 with the aim of evaluating whether icodextrin could reduce the long-term risk of surgery for SBO. Because of some concerns about complications (especially anastomotic leakage) after icodextrin use, a preplanned interim analysis of morbidity and mortality was conducted.

METHOD

Patients with colorectal cancer without metastasis were randomized 1:1 to receive standard surgery, with or without instillation of icodextrin in the abdominal cavity. For the first 300 patients, the 30-day follow-up data were collected from the Swedish ColoRectal Cancer Registry (SCRCR). Pre-, per- and postoperative data, morbidity and mortality were analysed.

RESULTS

Of the 300 randomized patients, 288 had a data file in the SCRCR. Twelve patients did not have cancer and another five did not have a resection, leaving 283 for analysis. The authors were blinded to the randomization groups. Demographic data were similar in both groups. The overall complication rate was 24% in Group 1 and 23% in Group 2 (P = 0.89). Four cases of anastomotic leakage were reported in Group 1 and five were reported in Group 2 (P = 1.0). Mortality, intensive care unit (ICU) stay and re-operations did not differ between the groups.

CONCLUSION

The pre-planned safety analysis of the first 300 patients enrolled in this randomized trial did not show any differences in adverse effects related to the use of icodextrin. All data were gathered from the SCRCR, giving us a strong message that we can continue to include patients in the trial.

Exogenous pulmonary surfactant prevents the development of intra-abdominal adhesions in rats

Intra-abdominal adhesions are major post-operative complications for which no effective means of prevention is available. We aimed to evaluate the efficacy of exogenous pulmonary surfactant administration in the prevention of post-operative abdominal adhesions. Rats were randomly assigned to undergo laparotomy (L) or gastroenterostomy (GE) and then treated with surfactant (groups L-S and GE-S, respectively). Intra-abdominal adhesions, collagen fibre content, metalloproteinase (MMP)-9, expression of growth factors (TGF-β, KGF and VEGF), type III procollagen (PCIII) and pro-caspase 3, as well as isolectin B4 and ED1-positive cells expressing MMP-9, were evaluated. Groups treated with surfactant (GE-S and L-S) exhibited fewer adhesions. A significant reduction in collagen fibre content was observed in GE-S compared to GE animals (P < 0.001). In situ and gelatin zymography analysis showed higher MMP-9 expression and activity in the GE-S group compared to the GE group (P < 0.05). ED1-positive cell counts were significantly higher in the GE-S group (P < 0.001) than in the GE group. Virtually all cells positive for ED1 were MMP-9+. Double-labelling of MMP-9 with IB4 showed no significant differences between GE-S and GE groups. TGF-β, KGF, PCIII and pro-caspase-3 mRNA expression decreased significantly in GE-S compared to GE animals (P < 0.05). Surfactant administration also reduced apoptosis in the GE-S group. These findings suggest that surfactant reduces the intra-abdominal adhesions triggered by laparotomy and gastrointestinal anastomosis, thus preventing fibrosis formation at the peritoneal surfaces. This preclinical study suggests an innovative treatment strategy for intra-abdominal adhesions with surfactant and to endorse its putative mechanism of action.

The Effects of Hydrophilic Polyethylene Glycol-Based Adhesion Barrier Use to Prevent Intra-abdominal Adhesions in Intra-abdominal Sepsis Model

Postoperative adhesion formation is still an important cause of morbidity and mortality. Hydrophilic polyethylene glycol-based adhesion barrier (SprayGel™, Confluent Surgical, Inc., Waltham, MA) is reported to prevent adhesion formation after gynecologic surgery. This study aims to determine the effectiveness of SprayGel™ on adhesion formation after laparotomy in an experimental septic peritonitis model. Wistar albino male rats with weights of 250-350 g were used in this study. Forty rats were grouped into four groups: group I (control), laparotomy and sham operation; group II, laparotomy and cecal ligation puncture (CLP); group III (SprayGel™), laparotomy, sham operation, and SprayGel™; group IV (CLP + SprayGel™), laparotomy, CLP, and SprayGel™. Intra-abdominal sepsis was achieved by perforating the cecum with a 26-gauge needle in selected groups. All animals were sacrificed after 10 days. The results were evaluated according to the score systems of Nair and Knightly. Kruskal-Wallis variance analysis was used for statistical analysis. There were significant differences for the development of adhesion between groups II (CLP) and III-IV (SprayGel™ - CLP + SprayGel™) (p < 0.02). Mortality and wound infection rates were significantly lower in the SprayGel™ treatment groups compared to control groups. Intraperitoneal administration of SprayGel™ significantly decreased the intraperitoneal adhesion formation, and it reduced mortality and wound infection as well.

An Autopsy Case of Amyotrophic Lateral Sclerosis with Diaphragm Pacing

Respiratory insufficiency is a critical problem in amyotrophic lateral sclerosis (ALS) patients. We herein present the case of an autopsied patient with sporadic ALS who underwent diaphragm pacing (DP). The pathology showed several localized adhesions with a markedly atrophied diaphragm. A marked loss of motor neurons with Bunina bodies and phosphorylated TDP-43 positive inclusions was found in the spinal cord and primary motor cortex. Mild hyalinization and a few multinucleated giant cells were present around the electrode tracks in the diaphragm. However, no infiltration of inflammatory cells was detected. Our findings suggest that full-time DP might not cause severe damage to adjacent diaphragm tissue.

Safety and Efficacy of Sodium Hyaluronate Gel and Chitosan in Preventing Postoperative Peristomal Adhesions After Defunctioning Enterostomy: A Prospective Randomized Controlled Trials

Peristomal adhesions complicate closure of defunctioning enterostomy. The efficacy and safety of sodium hyaluronate gel and chitosan in preventing postoperative adhesion have not been extensively studied. This study aims to evaluate the safety and efficacy of sodium hyaluronate gel and chitosan in the prevention of postoperative peristomal adhesions.This was a prospective randomized controlled study. One hundred and fourteen patients undergoing defunctioning enterostomy were enrolled. Patients were randomly assigned to receive sodium hyaluronate gel (SHG group) or chitosan (CH group) or no antiadhesion treatment (CON group) during defunctioning enterostomy. The safety outcomes included toxicities, stoma-related complications, and short-term and long-term postoperative complications. Eighty-seven (76.3%) of the 114 patients received closure of enterostomy, during which occurrence and severity of intra-abdominal adhesions were visually assessed by a blinded assessor.Incidence of adhesion appears to be lower in patients received sodium hyaluronate gel or chitosan but differences did not reach a significant level (SHG group vs CH group vs CON group: 62.1% vs 62.1% vs 82.8%, P = 0.15). Compared with the CON group, severity of postoperative adhesion was significantly decreased in the SHG and CH group (SHG group vs CH group vs CON group: 31.0% vs 27.6% vs 62.1%; P = 0.01). There was no significant difference in the occurrence of postoperative complications and other safety outcomes among the 3 groups.Sodium hyaluronate gel or chitosan smeared around the limbs of a defunctioning enterostomy was safe and effective in the prevention of postoperative peristomal adhesions.

Ghrelin ameliorates adhesions in a postsurgical mouse model

BACKGROUND

Peritoneal adhesion formation is a well-recognized consequence of abdominal and pelvic surgery, causing infertility, chronic pelvic pain, and intestinal obstruction. We hypothesized that ghrelin, a 28-amino acid peptide predominantly found in the stomach, plays an important role in preventing postoperative surgical adhesions. The purpose of this study was to develop a new surgical peritoneal adhesion model to define the role that ghrelin plays in wound healing and adhesion formation.

MATERIALS AND METHODS

C57BL/6 wild-type mice (n = 40) and growth hormone secretagogue receptor-knockout (GHSR KO) mice (n = 20) underwent a midline laparotomy to establish a peritoneal adhesion model characterized by the combination of two different techniques: ischemic peritoneal buttons and cecal multiple abrasion. All mice received intraperitoneal injections with ghrelin (0.16 mg/kg) or saline twice daily for 20 d after surgery. Peritoneal ischemic buttons were harvested to determine protein expression of collagen (Masson trichrome, picrosirius red stain, and Western blot).

RESULTS

The novel mouse model demonstrated consistent and easily reproducible formation of intra-abdominal adhesions. Ghrelin administration significantly reduced postoperative adhesion formation (P < 0.001) in wild-type mice. The antifibrotic effect of ghrelin in wild-type mice was confirmed by measuring collagen I protein levels via Western blot analysis. The anti-adhesion effect of ghrelin seen in wild-type mice was not detected in GHSR KO mice demonstrating that this effect is mediated by the GHSR-1a receptor.

CONCLUSIONS

Ghrelin administration may improve surgical outcome by reducing peritoneal adhesion formation and fibrotic response in a mouse model.

Effect of ligustrazine nanoparticles nano spray on transforming growth factor-β/Smad signal pathway of rat peritoneal mesothelial cells induced by tumor necrosis factor-α

OBJECTIVE

To study the effect of ligustrazine nanoparticles nano spray (LNNS) on transforming growth factor β (TGF-β)/Smad signal protein of rat peritoneal mesothelial cells (RPMC) induced by tumor necrosis factor α (TNF-α), and the anti-adhesion mechanism of LNNS in the abdominal cavity.

METHODS

The primary culture and subculture of rat peritoneal mesothelial cells (RPMC) was processed by trypsin digestion method in vitro. The third generation was identifified for experiment and divided into 5 groups: a blank group: RPMC without treatment; a control group: RPMC stimulated with TNF-α; RPMC treated by a low-dosage LNNS group (2.5 mg/L); RPMC treated by a medium-dosage LNNS group (5 mg/L); and RPMC treated by a high-dosage LNNS group (10 mg/L). Reverse transcription-polymerase chain reaction was applied to test the expression of fifibronectin, collagen I (COL-I), TGF-β mRNA, and Western blot method to test the Smad protein 7 expression of RPMC.

RESULTS

Compared with the blank group, a signifificant elevation in fifibronectin (FN), COL-I and TGF-β mRNA expression of RPMC were observed in the control group (P<0.05). Compared with the control group, LNNS suppressed the expressions of FN, COL-I and TGF-β mRNA in a concentrationdependent manner (P<0.05). The expression of Smad7 protein of RPMC was down-regulated by TNF-α stimulation, and up-regulated with the increase of LNNS dose (P<0.05).

CONCLUSIONS

TNF-α may induce changes in RPMC's viability, leading to peritoneal injury. LNNS could reverse the induction of fifibrosis related cytokine FN, COL-I and TGF-β, up-regulating the expression of Smad7 by TNF-α in RPMC, thus attenuate peritoneal injury by repairing mesothelial cells.

Analysis of adhesion formation of a new elastic thermoplastic polyurethane (TPU) mesh in comparison to polypropylene (PP) meshes in IPOM position

BACKGROUND

Postsurgical adhesions severely affect the patients' quality of life causing various complications like bowel obstruction or chronic pain. Especially the implantation of alloplastic prostheses in IPOM position for hernia repair carries a high risk of adhesion formation due to the close contact between mesh and viscera. The extent of adhesions mainly depends on the type and textile characteristics of the implanted mesh. The aim of this study was to examine the degree of adhesion formation of a newly developed, elastic thermoplastic polyurethane (TPU) mesh in comparison to polypropylene (PP) meshes in IPOM position in a rabbit model.

METHODS

Sixteen female chinchilla rabbits were laparoscopically operated. Two different meshes were placed to the left and the right lower abdominal wall in IPOM position in each rabbit. After 7 or 21 days, midline laparotomy was performed, the degree of adhesion formation was examined by the Diamond score and mesh elongation was measured under a force of 3N. Finally, the abdominal walls were explanted for immunohistochemical and histopathological investigations.

RESULTS

TPU meshes showed significantly lower Diamond scores than PP meshes. After explantation, mesh elongation of the TPU mesh was significantly larger than expansion of PP under a force of 3N. Thus, the TPU mesh preserved its elastic properties after 7 and 21 days. The amount of CD68 positive, Ki67 positive and apoptotic cells within the granuloma around the fibers did not show significant differences between the study groups.

CONCLUSIONS

The newly developed TPU mesh seems to reduce peritoneal adhesion formation in IPOM position in a rabbit model compared to PP meshes after 7 and 21 days. Immunohistochemistry did not reveal differences in biocompatibility of the two meshes used.

Thermosensitive hydrogel containing dexamethasone micelles for preventing postsurgical adhesion in a repeated-injury model

Tissue adhesion is a common complication after surgery. In this work, a dexamethasone loaded polymeric micelles in thermosensitive hydrogel composite (Dex hydrogel) was prepared, which combined the anti-adhesion barrier with controlled release of anti-adhesion drug. Dexamethasone (Dex) was encapsulated in polymeric micelles (Dex micelles), and then the Dex micelles were loaded into biodegradable and thermosensitive hydrogel. The obtained Dex hydrogel showed a temperature-dependent sol-gel-sol phase transition behavior. The Dex hydrogel could form a non-flowing gel in situ upon subcutaneous injection and gradually degrade in about 20 days. In addition, Dex hydrogel was assigned for anti-adhesion studies in a more rigorous recurrent adhesion animal model. Compared with normal saline (NS) and Dex micelles group, tissue adhesions in hydrogel and Dex hydrogel group were significantly alleviated. In Dex hydrogel group, the media adhesion score is 0, which was dramatically lower than that in blank hydrogel group (2.50, P < 0.001). In histopathological examination and scanning electron microscopy (SEM) analysis, an integral neo-mesothelial cell layer with microvilli on their surface was observed, which revealed that the injured parietal and visceral peritoneum were fully recovered without the concerns of adhesion formation. Our results suggested that Dex hydrogel may serve as a potential anti-adhesion candidate.

Early postoperative small bowel obstruction is an independent risk factor for subsequent adhesive small bowel obstruction in patients undergoing open colectomy

BACKGROUND

This prospective study was performed to investigate whether postoperative ileus (POI) or early postoperative small bowel obstruction (EPSBO) affects the development of adhesive small bowel obstruction (SBO) in patients undergoing colectomy.

METHODS

We prospectively enrolled 1,002 patients who underwent open colectomy by a single surgeon. POI was defined as the absence of bowel function for more than 5 days or as a delay in oral intake beyond 7 days postoperatively. EPSBO was defined as the clinical and radiologic identification of SBO after resuming oral intake between postoperative days 7 and 30. Adhesive SBO was defined as SBO developing after 30 days because of intraperitoneal adhesion. The associations between POI, EPSBO, patient- and surgery-related variables, and the development of adhesive SBO were analyzed.

RESULTS

A total of 85 (8.5 %) patients developed POI, and 42 patients (4.2 %) developed EPSBO, with seven patients experiencing both POI and EPSBO. During the follow-up period (median 51 months), 70 patients (7.0 %) developed adhesive SBO, six (8.6 %) of whom needed laparotomy. The occurrence of adhesive SBO was significantly higher in patients with EPSBO than in those without EPSBO (26.5 vs. 7.5 % at 5 years, P < 0.001), but not in patients with POI (13.4 vs. 7.8 % at 5 years, P = 0.158). Multivariable analysis showed colostomy (hazard ratio [HR] 2.530, P = 0.006) and EPSBO (HR 4.063, P < 0.001) as independent risk factors for adhesive SBO.

CONCLUSIONS

The development of adhesive SBO after colectomy is more frequent in patients with EPSBO and colostomy; however, POI does not increase the risk of adhesive SBO.

Efficacy and mechanism of tanshinone IIA liquid nanoparticles in preventing experimental postoperative peritoneal adhesions in vivo and in vitro

Up to 90% of patients develop adhesion following laparotomy. Upregulating fibrinolysis within the peritoneum reduces adhesions. Tanshinone IIA (Tan IIA) promotes fibrinolysis in hepatic fibrosis and the cardiovascular system and may play a role in preventing adhesions. We report preparation and characterization of liquid nanoparticles of Tan IIA for intravenous administration and investigate its feasibility in clinical practice. Tan IIA liquid nanoparticles (Tan IIA-NPs) were prepared using the emulsion/solvent evaporation method. Adhesions were induced in Sprague–Dawley rats by injuring the parietal peritoneum and cecum, followed by intravenous administration of various Tan IIA-NP dosages. The adhesion scores for each group were collected 7 days after the initial laparotomy. The activity of tissue-type plasminogen activator (tPA) was measured from the peritoneal lavage fluid. The messenger RNA and protein expression levels of plasminogen activator inhibitor-1 (PAI-1) were measured by quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay. TGF-β1 and collagen I expressions were measured immunohistochemically in the ischemic tissues. The effects of Tan IIA-NPs and free-Tan IIA on tPA and PAI-1 were measured in vitro in TGF-β1-induced HMrSV5 cells. Tan IIA-NPs exhibited small particle size, high encapsulation efficiency, good stability for storage, and safety for intravenous administration. Tan IIA-NPs were effective in preventing adhesion. Tan IIA-NPs increased tPA activity in peritoneal lavage fluid, and tPA mRNA and protein expression, and decreased PAI-1 mRNA and protein expression in the ischemic tissues. Moreover, Tan IIA-NPs decreased TGF-β1 and collagen I expressions in the ischemic tissues. Tan IIA-NPs administered via tail veins upregulated fibrinolysis in the peritoneum. In vitro studies showed that these effects may be mediated by the TGF-β signal pathway.

An injured tissue affects the opposite intact peritoneum during postoperative adhesion formation

The pathophysiology of adhesion formation needs to be clarified to reduce the adhesion-related morbidity. The epithelial characteristics of the peritoneum suggest a protective role against adhesion formation, yet how the peritoneum is involved in adhesion formation is not well characterized. We microscopically observed an experimental model of adhesion formation to investigate the effects of an injured tissue on the opposite intact peritoneum. Adhesions were induced between injured and intact hepatic lobes, and the intact peritoneum opposite to the injured tissue was examined for 8 days. The opposite intact peritoneum was denuded of mesothelial cells for 6 hours, and the remnant mesothelial cells changed morphologically for 24 hours. The detachment of mesothelial cells allowed fibrin to attach to the basement membrane of the opposite peritoneum, connecting the two lobes. Moreover, macrophages and myofibroblasts accumulated between the two lobes, and angiogenesis occurred from the opposite intact lobe to the injured lobe. These observations indicate that an injured tissue deprives the opposite intact peritoneum of its epithelial structure and causes fibrous adhesions to the opposite intact tissue. This study implies a possible role of mesothelial cells for barrier function against adhesion formation, that is, keeping mesothelial cells intact might lead to its prophylaxis.

Effect of intraperitoneal curcumin instillation on postoperative peritoneal adhesions

OBJECTIVE

The aim of this study was to determine the effect of curcumin on adhesion formation in a rat cecum abrasion model.

MATERIALS AND METHODS

Thirty Wistar rats were randomized into three groups; the control group received saline, the curcumin group received 10 mg/kg of curcumin after cecal abrasion, and in the sham group the abdominal wall was closed without any abrasion to the cecum. On day 15, adhesions were assessed blindly using a standardized scale, and histopathological samples were taken and examined.

RESULTS

There were no incisional hernias or wound dehiscences in any animals of the three groups. A comparison of adhesion scores showed a significant difference between the curcumin (median = 1) and the control group (median = 2; p < 0.05). The grade of inflammation of the curcumin (median = 1) and the sham (median = 0) group was significantly lower than that of the control group (median = 3; p < 0.01 and p < 0.001, respectively). Hydroxyproline levels were significantly lower in the sham (48.3 ± 11.8 µg/mg) and the curcumin (63.8 ± 13.9 µg/mg) group compared to the control group (85.7 ± 22.1 µg/mg; p < 0.05).

CONCLUSION

These data suggest that curcumin, administered intraperitoneally, was effective in the prevention of peritoneal adhesion formation.

Non-covalent photo-patterning of gelatin matrices using caged collagen mimetic peptides

To address the downside of conventional photo-patterning which can alter the chemical composition of protein scaffolds, we developed a non-covalent photo-patterning strategy for gelatin (denatured collagen) hydrogels that utilizes UV activated triple helical hybridization of caged collagen mimetic peptide (caged CMP). Here we present 2D and 3D photo-patterning of gelatin hydrogels enabled by the caged CMP derivatives, as well as creation of concentration gradients of CMPs. CMP's specificity for binding to gelatin allows patterning of almost any synthetic or natural gelatin-containing matrix, such as gelatin-methacrylate hydrogels and corneal tissues. This is a radically new tool for immobilizing drugs to natural tissues and for functionalizing scaffolds for complex tissue formation.

Electroacupuncture ST36 prevents postoperative intra-abdominal adhesions formation

BACKGROUND

We have recently proved electroacupuncture (EA) ST36 exerted an anti-inflammatory effect in the early phase of intra-abdominal adhesion formation. Evidences indicate that the anti-inflammatory effect of EA ST36 involves a cholinergic anti-inflammatory pathway-dependent mechanism via the vagus nerve. However, the exact effects and accurate vagal modulation of acupuncture in prevention of postoperative intra-abdominal adhesion formation has not been thoroughly evaluated.

MATERIALS AND METHODS

Sprague-Dawley rats subjected to abdominal adhesion lesions operation at the cecum and abdominal wall were randomly divided into six groups as follows: (a) EAN: EA non-channel acupoints; (b) EA: EA ST36 after abdominal lesions; (c) VGX/EA: vagotomy (VGX) after abdominal lesions, then EA ST36; (d) VGX/EAN: VGX after abdominal lesions, then EAN; (e) α-BGT/EA: intraperitoneal injection of α-bungarotoxin (α-BGT, an antagonist of α7 subunit of cholinergic nicotinic receptor) before EA ST36, and (f) α-BGT/EAN group: α-BGT injection before EAN. Seven days after abdominal surgical lesions, the levels of tumor necrosis factor-α (TNF-α) and vascular endothelial growth factor (VEGF) in the adhesive tissue were evaluated, macroscopic observation and histopathologic evaluation of adhesion formation and assessment of angiogenesis by immunohistochemical staining of platelet endothelial cell adhesion molecule-1 (CD31) were performed.

RESULTS

EA ST36 reduced TNF-α and VEGF levels in adhesive tissue homogenates 7 d after surgery, whereas vagotomy or intraperitoneal injection of α-BGT before EA ST36 reversed its suppressive effects. EA at non-channel acupoints with or without vagotomy or intraperitoneal injection of α-BGT before EA had no suppressive effects on TNF-α and VEGF levels. EA ST36 alleviated the adhesion formation, with both of macroscopic and histopathologic adhesion scores significantly lower than those of the EAN group (1.56 ± 0.29 versus 3.00 ± 0.82, 1.35 ± 0.4 versus 3.91 ± 0.8, respectively, both P < 0.05). Compared with the EAN group, EA ST36 significantly decreased angiogenesis evidenced by reduced CD31 positive microvessel density in adhesive tissue.

CONCLUSIONS

EA ST36 might reduce the postoperative local inflammatory response, attenuate the angiogenesis, and alleviate the adhesion formation partly via activating the cholinergic anti-inflammatory mechanism.

Role of laparoscopy in the prevention and in the treatment of adhesions

The formation of adhesions after abdominal surgery can lead to increased morbidity in children, increases the incidence of readmission, and may pose a significant challenge to subsequent surgical care over their lifetime. As the pathophysiology of peritoneal adhesion formation has been better understood, preventive strategies that minimize surgical trauma and contamination have been sought. Laparoscopy, over the past few decades, has become an increasingly utilized approach for many pediatric surgical problems and intuitively should have an advantage over open surgery in reducing adhesion formation. In this review, we examine the utility of laparoscopy in both the prevention and the treatment of intraabdominal adhesive disease in children.

[Post-cesarean parietal scar characteristics are predictive of pelvic adhesions. A prospective cohort study]

OBJECTIVE

To investigate whether abdominal scar characteristics could predict the incidence and severity of intra-abdominal adhesions found at repeat cesarean delivery.

PATIENTS AND METHODS

Prospective cohort study including 151pregnant women with at least one previous cesarean delivery and who delivered abdominally in the department of obstetrics and gynaecology of Farhat Hached teaching hospital-Sousse-Tunisia, during 6 months. Abdominal scar characteristics were studied. The main outcome measure(s) were the incidence and severity of intra-abdominal adhesions. Statistical analysis was performed using SPSS 18.0.

RESULTS

Of 151 women enrolled into this trial, 111 (73.5%) had adhesions, 57 (37.8%) had dense adhesions. Of all the abdominal scar characteristics studied, a depressed scar was associated with an increased incidence of both dense and filmy intra-abdominal adhesions and frozen pelvis if compared of women who did not have a depressed scar (P<10(-4) ; RR=7.6; IC=2.98-19.45). A number of previous cesarean section equal or more than 2 was also correlated with an increased incidence of severe intra-abdominal adhesions and frozen pelvis if compared with women who had only one previous cesarean section (P=0.002; RR=2.53; IC=1.16-5.56).

DISCUSSION AND CONCLUSION

A depressed abdominal scar of a previous cesarean delivery and a number of previous cesarean sections are significantly correlated with the incidence and severity of intra-abdominal adhesions.

Locally increased concentrations of inflammatory cytokines in an experimental intraabdominal adhesion model

BACKGROUND

Peritoneal adhesions may cause bowel obstruction, infertility, and pain. This study investigated cytokines, proteins and growth factors thought to promote formation of adhesions in an experimental intraabdominal adhesion model.

METHODS

Male Sprague-Dawley rats were subjected to laparotomy, cecal abrasion, and construction of a small bowel anastomosis and examined at various time points after surgery. Concentrations of cytokines and growth factors in plasma and peritoneal fluid were analyzed using electrochemoluminescence and quantitative sandwich enzyme immunoassay technique.

RESULTS

Concentrations of interleukin-6 (IL-6), interleukin-1beta (IL-1β), and tumor necrosis factor alpha (TNF-α) increased in peritoneal fluid from 6h after incision. Plasma concentrations of IL-6 increased at 6h, but plasma concentrations of IL-1β and TNF-α remained low. Peritoneal fluid concentrations of platelet-derived growth factor-BB (PDGF-BB), transforming growth factor beta1 (TGF-β1), vascular endothelial growth factor (VEGF), tissue-type plasminogen activator (tPA) and plasminogen activator inhibitor-1 (PAI-1) were below detection levels at all time points.

CONCLUSION

Early elevations of IL-6, IL-1β, and TNF-α concentrations in peritoneal fluid correlated to adhesion formation in this rodent model. Our model is relevant and reproducible, suitable for intervention, and indicates that antiadhesion strategies should be early, local and not systemic.

Intraarticular injections (corticosteroid, hyaluronic acid, platelet rich plasma) for the knee osteoarthritis

Osteoarthritis (OA) is a complex “whole joint” disease pursued by inflammatory mediators, rather than purely a process of “wear and tear”. Besides cartilage degradation, synovitis, subchondral bone remodeling, degeneration of ligaments and menisci, and hypertrophy of the joint capsule take parts in the pathogenesis. Pain is the hallmark symptom of OA, but the extent to which structural pathology in OA contributes to the pain experience is still not well known. For the knee OA, intraarticular (IA) injection (corticosteroids, viscosupplements, blood-derived products) is preferred as the last nonoperative modality, if the other conservative treatment modalities are ineffective. IA corticosteroid injections provide short term reduction in OA pain and can be considered as an adjunct to core treatment for the relief of moderate to severe pain in people with OA. IA hyaluronic acid (HA) injections might have efficacy and might provide pain reduction in mild OA of knee up to 24 wk. But for HA injections, the cost-effectiveness is an important concern that patients must be informed about the efficacy of these preparations. Although more high-quality evidence is needed, recent studies indicate that IA platelet rich plasma injections are promising for relieving pain, improving knee function and quality of life, especially in younger patients, and in mild OA cases. The current literature and our experience indicate that IA injections are safe and have positive effects for patient satisfaction. But, there is no data that any of the IA injections will cause osteophytes to regress or cartilage and meniscus to regenerate in patients with substantial and irreversible bone and cartilage damage.

Long-term follow-up for adhesive small bowel obstruction after open versus laparoscopic surgery for suspected appendicitis

OBJECTIVE

The aim of the present study was to compare the frequency of readmissions due to small bowel obstruction (SBO) after open versus laparoscopic surgery performed for suspected acute appendicitis.

BACKGROUND

Appendicitis is a common disease, with a lifetime risk of approximately 7%. Appendectomy is the treatment of choice for most patients. Postoperative adhesions are common after abdominal surgery, including appendectomy.

MATERIALS AND METHODS

Consecutive patients, 16 years or older, operated on because of suspected appendicitis at 2 university hospitals between 1992 and 2007 were included. The prime approach was open at one hospital and laparoscopic at the other hospital. Open and laparoscopic procedures were compared retrospectively, reviewing the patients' charts until the middle of 2012. Hospitalization for SBO after index surgery was registered.

RESULTS

A total of 2333 patients in the open group and 2372 patients in the laparoscopic group were included. The frequency of hospitalization for SBO was low in both groups, although a difference between the groups was identified (1.0% in the open group and 0.4% in the laparoscopic group) (P = 0.015).

CONCLUSIONS

Hospitalization due to SBO, between open and laparoscopic procedures, in patients operated on because of suspected appendicitis demonstrated a significant difference, favoring the laparoscopic approach. The frequency of SBO after the index surgery was, though, low in both groups.

Should adhesive small bowel obstruction be managed laparoscopically? A National Surgical Quality Improvement Program propensity score analysis

BACKGROUND

Celiotomy is the most common approach for refractory small bowel obstruction (SBO). Small reviews suggest that a laparoscopic approach is associated with shorter stay and less morbidity. Given the limitations of previous studies, we sought to evaluate outcomes of laparoscopic (L) compared with open (O) adhesiolysis for SBO, using the National Surgical Quality Improvement Program data set.

METHODS

Patients from the American College of Surgeons' National Surgical Quality Improvement Program 2005 to 2009 database who underwent surgery for SBO were stratified based on surgical approach. A propensity score to undergo L instead of O was calculated based on demographics, comorbidities, physiology, and laboratory values. Logistic regression was then used to determine differences in outcomes between those propensity score-matched patients who actually underwent L compared with O surgery.

RESULTS

There were 6,762 patients who underwent adhesiolysis. The propensity score-matching process created 222 matched patients in L and O groups. Laparoscopy was associated with significantly lower rates of any complication (odds ratio [OR] 0.41; 95% confidence interval [CI], 0.28-0.60), including superficial site infections (OR, 0.15; 95% CI, 0.05-0.49), intraoperative transfusion (OR, 0.22; 95% CI, 0.05-0.90), and shorter hospital stay (4 days vs. 10 days; p < 0.001). There was no significant difference in operative time, rates of reoperation within 30 days, or mortality.

CONCLUSION

Laparoscopic treatment of SBO is associated with lower rates of postoperative morbidity compared with laparotomy as well as shorter hospital stay. Laparoscopic treatment of surgical SBO is not associated with higher rates of early reoperation and seems to be associated with lower resource use.

LEVEL OF EVIDENCE

Therapeutic study, level IV.

Does thermodynamic stability of peritoneal collagen change during laparoscopic cholecystectomies? A differential scanning calorimetry (DSC) study

Background

Carbon dioxide pneumoperitoneum used during laparoscopic surgeries alters the integrity of the peritoneum and results in denudation of the basal lamina that might cause altered immune response, inhibited fibrinolysis, hypoxia, and acidosis. The changes in the structure of pneumoperitoneum were described as bulging of mesothelial cells, irregular cell junction’s cell membrane degradation, and mesodermal edema. As denaturation of peritoneal proteins reflects overall condition of its structure and interactions with the surrounding molecules, the physical status of collagen was assessed on the basis of parameters of thermal denaturation measured by DSC method.

Methods

Twenty-four female patients operated on due to cholelithiasis were enrolled in this study. Laparoscopic cholecystectomy was performed using standard four-trocar technique, and standard values of insufflated carbon dioxide pneumoperitoneum were used. After trocar placement, the first collection of peritoneal sample (sample A) was performed. The second peritoneal sample (sample B) was collected after the removal of gall bladder. Differential scanning calorimetry (Q200 calorimeter, TA Instruments) was performed on samples defrosted at room temperature.

Results

In all samples of peritoneum, a nonreversible endothermal process recognized as denaturation was observed. Sample B obtained at the end of surgery did not differ from sample A obtained at the beginning in terms of all parameters under study. Temperature of denaturation in A and B was correlated only marginally, but enthalpy and specific heat were significantly correlated. The analysis of data from DSC measurements did not reveal differences in physical stability of collagen in peritoneal samples obtained at the beginning and at the end of surgery. Significant negative correlations between duration of CO₂ pneumoperitoneum and enthalpy of denaturation in sample B were found.

Conclusions

Differences in enthalpy of denaturation may reflect a quantitative relation between amount of native collagen molecules in the sample and other, non-collagenous components or impaired collagen.

Preventing intraperitoneal adhesions with linezolid and hyaluronic acid/carboxymethylcellulose: a comparative study in cecal abrasion model

BACKGROUND

We aimed to compare the effectiveness of linezolid in preventing intraperitoneal adhesions with hyaluronic acid + carboxymethylcellulose (Seprafilm).

METHODS

Thirty rats were divided randomly into 3 groups: Group I (control), untreated; Group II (Seprafilm); and Group III (linezolid). All rats were sacrificed on the 14th day after surgery. Macroscopic adhesion, inflammation, and fibrosis were evaluated.

RESULTS

The multiple comparisons between groups showed a statistically significant difference for adhesion. There were statistically significant differences between Group I and II and I and III, but no statistically significant difference between Group II and III. The multiple comparisons between the groups showed a statistically significant difference for inflammation and fibrosis. For inflammation and fibrosis, there was a statistically significant difference between Group I and II and I and III, but no statistically significant difference between Group II and III.

CONCLUSION

The efficiency of linezolid in reducing the formation of intraperitoneal adhesions was statistically significant compared with the control group.

Feline gastrointestinal surgery: principles and essential techniques

PRACTICAL RELEVANCE

Gastrointestinal (GI) surgical procedures are performed commonly in cats in general practice for both diagnostic and treatment purposes. It is essential that the surgeon understands and adheres to the principles of GI surgery in order that postoperative morbidity and mortality are kept to a minimum.

AUDIENCE

This review is aimed at feline and general practitioners wanting to update their core skills in GI surgery. It discusses anatomical considerations and surgical principles, and aims to familiarise the surgeon with techniques (some well established, others newer) that will help to promote surgical success.

EQUIPMENT

Standard general surgical equipment is required, together with the facilities to provide adequate pre-, intra- and postoperative patient care.

EVIDENCE BASE

The author draws on clinical experience and evidence from the literature, where appropriate, in reviewing the guidance and techniques under discussion.

Hypothermia decreases postoperative intra-abdominal adhesion formation

BACKGROUND

Hypothermia may decrease postoperative intra-abdominal adhesion. We sought to determine the most suitable temperature for hypothermia for decreasing postoperative adhesion formation.

METHODS

One hundred and twenty male BALB/c mice weighing 25 to 30 g were randomized into 5 groups: adhesion model with infusion of cold saline at (I) 15°C; (II) 10°C; or (III) 4°C; (IV) adhesion model without infusion of saline; and (V) sham operation without infusion of saline. Adhesion scores, incidence of adhesion, and serum cytokine levels were measured at postoperative days 1, 3, 7, and 14.

RESULTS

Adhesion scores among groups I, II, and III did not differ significantly. Interleukin-6 was significantly decreased in groups I, II, and III, compared to the levels in groups IV and V (P < .05). Tumor necrosis factor-α levels in groups I and II were significantly decreased compared to those in groups III, IV, and V (P < .05).

CONCLUSION

We suggest that 15°C is the appropriate temperature for induction of hypothermia to decrease postoperative intra-abdominal adhesion formation.

Peritoneal response to abdominal surgery: the role of equine abdominal adhesions and current prophylactic strategies

Intra-abdominal adhesions constitute a significant clinical and surgical problem that can lead to complications such as pain and bowel occlusion or subocclusion. These adhesions are frustrating and potentially fatal, representing a major postoperative complication in abdominal surgery. It is estimated that 32% of horses undergoing laparotomy will present clinical symptoms due to adhesions, but the true prevalence is not known because a large proportion of animals with postoperative recurrent colics are medically treated or submitted to euthanasia without necropsy. Adhesions are highly cellular, vascularized, dynamic structures that are influenced by complex signaling mechanisms. Understanding their pathogenesis could assist in applying better therapeutic strategies and in developing more effective antiadhesion products. Currently, there are no definitive strategies that prevent adhesion formation, and it is difficult to interpret the results of existing studies due to nonstandardization of an induction model and evaluation of their severity. The best clinical results have been obtained from using minimally traumatic surgical techniques, anti-inflammatory agents, antimicrobials, anticoagulants, and mechanical separation of serosal surfaces by viscous intraperitoneal solutions or physical barriers. This paper aims to review adhesion formation pathogenesis, guide the understanding of major products and drugs used to inhibit adhesion formation, and address their effectiveness in the equine species.

Bologna guidelines for diagnosis and management of adhesive small bowel obstruction (ASBO): 2013 update of the evidence-based guidelines from the world society of emergency surgery ASBO working group

Background

In 2013 Guidelines on diagnosis and management of ASBO have been revised and updated by the WSES Working Group on ASBO to develop current evidence-based algorithms and focus indications and safety of conservative treatment, timing of surgery and indications for laparoscopy.

Recommendations

In absence of signs of strangulation and history of persistent vomiting or combined CT-scan signs (free fluid, mesenteric edema, small-bowel feces sign, devascularization) patients with partial ASBO can be managed safely with NOM and tube decompression should be attempted. These patients are good candidates for Water-Soluble-Contrast-Medium (WSCM) with both diagnostic and therapeutic purposes. The radiologic appearance of WSCM in the colon within 24 hours from administration predicts resolution. WSCM maybe administered either orally or via NGT both immediately at admission or after failed conservative treatment for 48 hours. The use of WSCM is safe and reduces need for surgery, time to resolution and hospital stay.

NOM, in absence of signs of strangulation or peritonitis, can be prolonged up to 72 hours. After 72 hours of NOM without resolution, surgery is recommended.

Patients treated non-operatively have shorter hospital stay, but higher recurrence rate and shorter time to re-admission, although the risk of new surgically treated episodes of ASBO is unchanged. Risk factors for recurrences are age <40 years and matted adhesions. WSCM does not decrease recurrence rates or recurrences needing surgery.

Open surgery is often used for strangulating ASBO as well as after failed conservative management. In selected patients and with appropriate skills, laparoscopic approach is advisable using open access technique. Access in left upper quadrant or left flank is the safest and only completely obstructing adhesions should be identified and lysed with cold scissors. Laparoscopic adhesiolysis should be attempted preferably if first episode of SBO and/or anticipated single band. A low threshold for open conversion should be maintained.

Peritoneal adhesions should be prevented. Hyaluronic acid-carboxycellulose membrane and icodextrin decrease incidence of adhesions. Icodextrin may reduce the risk of re-obstruction. HA cannot reduce need of surgery.

Adhesions quantification and scoring maybe useful for achieving standardized assessment of adhesions severity and for further research in diagnosis and treatment of ASBO.

Influence of 4% icodextrin solution on peritoneal tissue response and adhesion formation

BACKGROUND

Postoperative peritoneal adhesion formation following abdominal surgery remains a relevant surgical problem. The application of soluble physico-chemical barriers like 4% icodextrin is one approach to protect the peritoneal surface from getting linked to adhesive scar. The aim of this study was to investigate the influence of 4% icodextrin on peritoneal tissue response both of visceral and parietal peritoneum, adhesion formation and wound healing.

METHODS

40 rats were divided into two groups. After creation of an intraabdominal defect, either 4% icodextrin (Adept®) or sodium chloride was applied. Animals were sacrificed after 7 and 21 days. Adhesions were scored by an adhesion score. Furthermore, immunohistochemical investigations were conducted to determine the discrete influence of icodextrin on the parietal and visceral peritoneal tissue responses (CD68+ macrophages, CD3+ T-lymphocytes, vimentin for mesenchymal cells, HBME-1 for mesothelial cells, and as components of wound healing COX-2, C-myc, catenin).

RESULTS

Postoperative peritoneal adhesions were predominantly present in the sodium chloride group as compared to the icodextrin group (14/19 (74%) vs. 9/19 (47%); p = 0.048). The adhesion score however did not reveal any significant differences, (p = 0.614). Furthermore, the expression of vimentin in both the parietal and visceral peritoneum after 21 days was significantly lower in the icodextrin group than in the sodium chloride group (p = 0.038 and p = 0.028, respectively). No significant differences were observed for macrophages, lymphocytes, reperitonealisation or the expression of COX-2, C-myc or Catenin.

CONCLUSIONS

The intraperitoneal application of 4% icodextrin reduces adhesion formation in comparison to sodium chloride. 4% icodextrin solution reduces the inflammatory and mesenchymal infiltrate in the wounded area, thus improving the ratio of mesothel cells to mesenchymal infiltrate. As demonstrated, icodextrin is able to ameliorate the local tissue response. Further experimental studies would be done to elaborate the impact on the early response of the adaptive immune system, which may then trigger the subsequent wound healing and tissue repair.

Recovery of immunological homeostasis positively correlates both with early stages of right-colorectal cancer and laparoscopic surgery

Differences in postoperative outcome and recovery between patients subjected to laparoscopic-assisted versus open surgery for colorectal cancer (CRC) resection have been widely documented, though not specifically for right-sided tumors. We investigated the immunological responses to the different surgical approaches, by comparing postoperative data simultaneously obtained at systemic, local and cellular levels. A total of 25 right-sided CRC patients and controls were managed, assessing -in the immediate followup- the conventional perioperative parameters and a large panel of cytokines on plasma, peritoneal fluids and lipopolysaccharide (LPS)-stimulated peripheral blood mononuclear cells (PBMC) tissue cultures. A general better recovery for patients operated with laparoscopy compared to conventional procedure, as indicated by the analysis of typical pre- and post-surgical parameters, was observed. The synchronous evaluation of 12 cytokines showed that preoperative plasma levels of the proinflammatory cytokines IL-6, IL-8, IL-1β, TNFα were significantly lower in healthy donors versus CRC patients and that such differences progressively increase with tumor stage. After surgery, the IL-6 and IL-8 increases were significantly higher in open compared to laparoscopic approach only in CRC at early stages. The postsurgical whole panel of cytokine levels were significantly higher in peritoneal fluids compared to corresponding plasma, but with no significant differences depending on kind of surgery or stage of disease. Then we observed that, pre- compared to the corresponding post-surgery derived LPS-stimulated PBMC cultures, produced higher supernatant levels of the whole cytokine panel. In particular IL-6 in vitro production was significantly higher in PBMC derived from patients subjected to laparoscopic versus open intervention, but -again- only in CRC at early stages of disease. Our results thus show that laparoscopy compared to open right resection is associated with a shorter compromission of the immunological homeostasis, mainly in early stages of right-CRC patients.

Novel thermosensitive hydrogel for preventing formation of abdominal adhesions

Adhesions can form after almost any type of abdominal surgery. Postoperative adhesions can be prevented by improved surgical techniques, such as reducing surgical trauma, preventing ischemia, and avoiding exposure of the peritoneal cavity to foreign materials. Although improved surgical techniques can potentially reduce formation of adhesions, they cannot be eliminated completely. Therefore, finding more effective methods to prevent postoperative adhesions is imperative. Recently, we found that a novel thermosensitive hydrogel, ie, poly(ε-caprolactone)-poly(ethylene glycol)-poly(ε-caprolactone) (PCEC) had the potential to prevent postoperative adhesions. Using the ring-opening polymerization method we prepared a PCEC copolymer which could be dissolved and assembled at 55°C into PCEC micelles with mean size of 25 nm. At body temperature, a solution containing PCEC micelles could convert into a hydrogel. The PCEC copolymer was biodegradable and had low toxicity in vitro and in vivo. We found that most animals in a hydrogel-treated group (n = 10) did not develop adhesions. In contrast, 10 untreated animals developed adhesions that could only be separated by sharp dissection (P < 0.001). The hydrogel could adhere to peritoneal wounds and degraded gradually over 7-9 days, transforming into a viscous fuid that was completely absorbed within 12 days. The injured parietal and visceral peritoneum remesothelialized over about seven and nine days, respectively. This study confirms that PCEC hydrogel has potential application in the prevention of postoperative adhesions.