Influence of gentamicin-coded PVDF suture material on the healing of intestinal anastomosis in a rat model.

PURPOSE: Intestinal anastomosis is a fundamental procedure in general surgery and required to restore intestinal continuity following resection. The aim of this study was to evaluate whether a gentamicin-coated polyvinylidene fluoride (PVDF) suture material has beneficial effect on anastomotic healing. METHODS: Ninety Sprague-Dawley rats were divided into three groups: a PVDF-suture group, a gentamicin-coated PVDF (GPVDF)-suture group and a control group using Maxon® (polyglycolid-co-trimethylene carbonate). For each animal, a colonic anastomosis was performed. Ten animals from each group were sacrificed on postoperative days 3, 5, and 14. Measurements of anastomotic bursting pressure were performed on days 3 and 5. At each time, collagen type I/III ratio, MMP 2 and MMP-9 expression and the proliferation index (Ki67) were analyzed. RESULTS: In total, 90 animals underwent surgery without postoperative complications. Bursting strength in the GPVDF group was significantly elevated on day 5. Immunohistochemistry showed significant increase of the collagen type I/III ratio for PVDF and GPVDF on days 3 and 5. MMP2 was significantly increased for PVDF on days 3 and 5 and for GPVDF on day 5. The analysis of MMP9 revealed significant increase compared to control on day 3 and 5 (GPVDF) as well as on day 5 (PVDF). Staining for Ki67 revealed a significant elevation on postoperative day 3 for the PVDF and the GPVDF group. CONCLUSIONS: The present data shows the feasibility of PVDF as suture material for colonic anastomosis and confirms the ability of gentamicin to increase the stability of colonic anastomosis when used as coating material.

Utility of Magnetic Resonance Imaging to Monitor Surgical Meshes: Correlating Imaging and Clinical Outcome of Patients Undergoing Inguinal Hernia Repair.

OBJECTIVES: From a surgeon's point of view, meshes implanted for inguinal hernia repair should overlap the defect by 3 cm or more during implantation to avoid hernia recurrence secondary to mesh shrinkage. The use of magnetic resonance imaging (MRI)-visible meshes now offers the opportunity to noninvasively monitor whether a hernia is still covered sufficiently in the living patient. The purpose of this study was therefore to evaluate the efficacy of hernia repair after mesh implantation based on MRI findings (mesh coverage, visibility of hernia structures) and based on the patient's postoperative symptoms. MATERIALS AND METHODS: In this prospective study approved by the ethics committee, 13 MRI-visible meshes were implanted in 10 patients (3 bilaterally) for inguinal hernia repair between March 2012 and January 2013. Senior visceral surgeons (>7 years of experience) implanted the meshes via laparoscopic transabdominal preperitoneal procedure. Magnetic resonance imaging was performed within 1 week and at 3 months after surgery at a 1.5-T system. Mesh position, deformation, and coverage of the hernia were visually assessed in consensus and rated on a 4-point semiquantitative scoring system. Distances of hernia center point to the mesh borders (overlap) were measured. Mesh position and hernia coverage postoperatively and at 3 months after implantation were correlated with the respective patients' clinical symptoms. Statistical analysis was performed using the Wilcoxon signed rank test. RESULTS: Two of the 13 meshes presented with an atypical mesh configuration along the course of psoas muscle with a short medial overlap of less than 2 cm. Eleven of the 13 meshes exhibited a typical mesh configuration with lateral folding and initial overlap of more than 2 cm. Between baseline and 3 months' follow-up, average overlap decreased in the medial direction by -10% (3.75 cm vs 3.36 cm, P = 0.22), in the lateral direction by -20% (3.55 cm vs 2.82 cm, P = 0.01), in the superior direction by -2% (5.82 cm vs 5.72 cm, P = 0.55), and in the posterior direction by -19% (4.11 cm vs 3.34 cm, P = 0.01). Between baseline and 3 months' follow-up, mesh folding increased mildly in the medial direction, whereas no change was found in the other directions. Individual folds of the mesh were flexible over time, whereas the gross visual configuration and location of meshes did not change. Four of the 13 former hernia sites were mildly painful at follow-up, whereas 9 of the 13 were completely asymptomatic. No correlation between clinical symptoms and mesh position or hernia coverage was found. CONCLUSIONS: Our results suggest that the actual postoperative mesh position after release of laparoscopic pneumoperitoneum may deviate from its position during surgery. Gross mesh position and configuration differed between patients but did not change within a given patient over the observation period of 3 months after surgery. We did not find a correlation between clinical symptoms and mesh configuration or position. Shrinkage of meshes does occur, yet not as concentric process, but regionally variable, leading to a reduced hernia coverage of up to -20% in the lateral and posterior directions.

Influence of CD68+ macrophages and neutrophils on anastomotic healing following laparoscopic sigmoid resection due to diverticulitis.

BACKGROUND: The aim of this prospective study was to evaluate the predictive value of a potential preexisting low-grade inflammation regarding the incidence of anastomotic leakage in elective laparoscopic sigmoid resection due to diverticulitis. METHODS: Patients with either chronically recurrent diverticulitis or sigmoid stenosis caused by chronic diverticulitis were included in this study. All patients with acute local or systemic inflammation were excluded. Detailed patient information (e.g. American Society of Anesthesiologists (ASA) grade, comorbidities, duration of hospital stay, and anastomotic leakage) was prospectively recorded. CD68(+) macrophages, neutrophils, CD3(+) T-lymphocytes, CD11c(+) dendritic cells, MHCII, TNFR1, and NF-κB were evaluated by immunohistochemistry within the acquired sample of colonic bowel wall tissue. Clinical and immunohistochemical data was compared between groups (leakage vs. no leakage). Additionally, a matched-pair analysis was performed due to the widely heterogeneous groups concerning the number of patients and to minimize the effect of extraneous variables. RESULTS: A total of 83 patients were included in the study, of which 7 patients suffered an anastomotic leakage. Neither the clinical nor the immunohistochemical parameters were significantly different between the groups. The matched-pair analysis revealed a nonsignificant increase in mean duration of hospital stay for the group with anastomotic leakage and a significantly higher percentage of CD68(+) macrophages and neutrophils in the colonic wall obtained at the index operation in both the mucosal and submucosal layers for the leakage group. CONCLUSIONS: A preexisting low-grade inflammation represented by infiltrates of macrophages and neutrophils is a predictor for increased risk of developing colon anastomotic leakage.

First in vivo visualization of MRI-visible IPOM in a rabbit model.

BACKGROUND: Application of a mesh in presence of pneumoperitoneum may cause deformation or wave formation when gas is released. Moreover, mesh shrinkage during subsequent wound healing cannot be detected in vivo without invasive diagnostics. Using MRI-visible polyvinylidene fluoride (PVDF) mesh, the extend of mesh deformation and shrinkage could be objectified by MRI for the first time. MATERIALS AND METHODS: Laparoscopic intraperitoneal onlay mesh (IPOM) implantation was performed in 10 female rabbits using ferro-oxide loaded PVDF meshes. MRI measurements were performed postoperatively at days 1 and 90. After three-dimensional reconstruction of all MRI images the total surface and the effective surface of the implanted mesh were explored and calculated computer-assisted. RESULTS: In all cases, the mesh could be identified in MRI. The subsequent three-dimensional reconstruction always allowed a calculation of the mesh area. In relation to the original size of the used textile implant, we found neither a significant reduction of the effective mesh surface after release of the pneumoperitoneum at day 1 after laparoscopic surgery nor a significant change of the total surface of this large pore mesh by the end of the observation period. CONCLUSIONS: In vivo investigation of mesh surface via MRI could exclude a significant initial reduction of the effective mesh surface after release of pneumoperitoneum, in this IPOM rabbit model. A further subsequent shrinkage of these large pore PVDF meshes could be excluded, as well. Imaging of MRI-visible IPOM mesh turned out to be a sufficient tool to objectify mesh configuration and position in vivo.

Protective role of peroxisome proliferator-activated receptor-ß/δ in septic shock.

RATIONALE: Peroxisome proliferator-activated receptor (PPAR)-ß/δ is a transcription factor that belongs to the PPAR nuclear hormone receptor family, but the role of PPAR-ß/δ in sepsis is unknown. OBJECTIVES: We investigated the role of PPAR-ß/δ in murine models of LPS-induced organ injury and dysfunction and cecal ligation and puncture (CLP)-induced polymicrobial sepsis. METHODS: Wild-type (WT) and PPAR-ß/δ knockout (KO) mice and C57BL/6 mice were subjected to LPS for 16 hours. C57BL/6 mice received the PPAR-ß/δ agonist GW0742 (0.03 mg/kg intravenously, 1 h after LPS) or GW0742 plus the PPAR-ß/δ antagonist GSK0660 (0.1 mg/kg intravenously, 30 min before LPS). CD-1 mice subjected to CLP received GW0742 or GW0742 plus GSK0660. MEASUREMENTS AND MAIN RESULTS: In PPAR-ß/δ KO mice, endotoxemia exacerbated organ injury and dysfunction (cardiac, renal, and hepatic) and inflammation (lung) compared with WT mice. In C57BL/6 mice subjected to endotoxemia, GW0742 significantly (1) attenuated organ (cardiac and renal) dysfunction and inflammation (lung); (2) increased the phosphorylation of Akt and glycogen synthase kinase (GSK)-3ß; (3) attenuated the increase in extracellular signal-regulated kinase (ERK)1/2 and signal transducer and activator of transcription (STAT)-3 phosphorylation; and (4) attenuated the activation of nuclear factor (NF)-κB and the expression of inducible nitric oxide synthase (iNOS). In CD-1 mice subjected to CLP, GW0742 improved 10-day survival. All the observed beneficial effects of GW0742 were attenuated by the PPAR-ß/δ antagonist GSK0660. CONCLUSIONS: PPAR-ß/δ protects against multiple organ injury and dysfunction, and inflammation caused by endotoxic shock and improves survival in polymicrobial sepsis by a mechanism that may involve activation of Akt and inhibition of GSK-3ß and NF-κB.