Self-adhesive hydrogel meshes reduce tissue incorporation and mechanical behavior versus microgrips self-fixation: a preclinical study.

PURPOSE: Atraumatic mesh fixation for abdominal hernia repair has been developed to avoid the disadvantages of classical fixation with sutures, which is considered a cause of chronic pain and discomfort. This study was designed to analyze, in the short and medium term, the biological and mechanical behavior of two self-fixing meshes compared to that of a polypropylene (PP) mesh fixed with a cyanoacrylate (CA) tissue adhesive. METHODS: Partial abdominal wall defects (6 × 4 cm) were created in New Zealand rabbits (n = 36) and repaired using a self-adhesive hydrogel mesh (Adhesix™), a self-gripping mesh (ProGrip™) or a PP mesh fixed with CA (Surgipro™ CA). After 14 and 90 days, the host tissue incorporation, macrophage response and biomechanical strength were examined. RESULTS: At 14 and 90 days, the ProGrip and Surgipro CA meshes showed good host tissue incorporation; however, the Adhesix implants presented poor integration, seroma formation and a higher degree of shrinkage. The Adhesix hydrogel was completely reabsorbed at 14 days, whereas ProGrip microhooks were observed at all study times. The macrophage response was higher in the ProGrip and Surgipro CA groups at 14 and 90 days, respectively, and decreased over time. At 90 days, the ProGrip implants showed the highest tensile strength values and the Adhesix implants showed the highest failure stretch. CONCLUSION: Meshes with mechanical microgrip self-fixation (ProGrip) show better biological and mechanical behavior than those with adhesive hydrogel (Adhesix) in a preclinical model of abdominal hernia repair in rabbits.

Behaviour at the peritoneal interface of next-generation prosthetic materials for hernia repair.

BACKGROUND: When using a prosthetic material in hernia repair, the behaviour of the mesh at the peritoneal interface is especially important for implant success. Biomaterials developed for their intraperitoneal placement are known as composites and are made up of two different-structure materials, one is responsible for good integration within host tissue and the other is responsible to make contact with the viscera. This study examines the behaviour at the peritoneal level of two composites, the fully degradable Phasix-ST® and the partially degradable Symbotex®. A polypropylene mesh (Optilene®) served as control. METHODS: Sequential laparoscopy from 3 to 90 days, in a preclinical model in the New Zealand white rabbit, allowed monitoring adhesion formation. Morphological studies were performed to analyse the neoperitoneum formed in the repair process. Total macrophages were identified by immunohistochemical labelling. To identify the different macrophage phenotypes, complementary DNAs were amplified by qRT-PCR using specific primers for M1 (TNF-α/CXCL9) and M2 (MRC1/IL-10) macrophages. RESULTS: The percentage of firm and integrated adhesions remained very high in the control group over time. Both composites showed a significant decrease in adhesions at all study times and in qualitative terms were mainly loose. Significant differences were also observed from 7 days onwards between the two composites, increasing the values in Phasix over time. Neoperitoneum thickness for Phasix was significantly greater than those of the other meshes, showing mature and organized neoformed connective tissue. Immunohistochemically, a significantly higher percentage of macrophages was observed in Symbotex. mRNA expression levels for the M2 repair-type macrophages were highest for Phasix but significant differences only emerged for IL-10. CONCLUSIONS: Fewer adhesions formed to the Symbotex than Phasix implants. Ninety days after implant, total macrophage counts were significantly higher for Symbotex, yet Phasix showed the greater expression of M2 markers related to the tissue repair process.

Antibacterial Biopolymer Gel Coating on Meshes Used for Abdominal Hernia Repair Promotes Effective Wound Repair in the Presence of Infection.

Prosthetic mesh infection is a devastating complication of abdominal hernia repair which impairs natural healing in the implant area, leading to increased rates of patient morbidity, mortality, and prolonged hospitalization. This preclinical study was designed to assess the effects on abdominal wall tissue repair of coating meshes with a chlorhexidine or rifampicin-carboxymethylcellulose biopolymer gel in a Staphylococcus aureus (S. aureus) infection model. Partial abdominal wall defects were created in New Zealand white rabbits (n = 20). Four study groups were established according to whether the meshes were coated or not with each of the antibacterial gels. Three groups were inoculated with S. aureus and finally repaired with lightweight polypropylene mesh. Fourteen days after surgery, implanted meshes were recovered for analysis of the gene and protein expression of collagens, macrophage phenotypes, and mRNA expression of vascular endothelial growth factor (VEGF) and matrix metalloproteinases (MMPs). Compared to uncoated meshes, those coated with either biopolymer gel showed higher collagen 1/3 messenger RNA and collagen I protein expression, relatively increased VEGF mRNA expression, a significantly reduced macrophage response, and lower relative amounts of MMPs mRNAs. Our findings suggest that following mesh implant these coatings may help improving abdominal wall tissue repair in the presence of infection.

Antibacterial polypropylene mesh fixation with a cyanoacrylate adhesive improves its response to infection.

BACKGROUND: Antibacterial meshes for hernia repair seek to avoid infection in the patient. As these biomaterials are especially prone to bacteria settling at their sutured borders, this study examines whether the use of a cyanoacrylate tissue adhesive could improve mesh behavior at the fixation zones. METHODS: First, antibacterial polypropylene meshes were prepared by soaking in 0.05% chlorhexidine, and the response of n-hexyl cyanoacrylate to contamination with Staphylococcus aureus ATCC25923 was assessed in vitro. Then, in a preclinical model, partial defects (5 x 3 cm) were created in the abdominal wall of 18 New Zealand White rabbits and repaired with mesh to establish the following 3 study groups: (1) mesh without chlorhexidine fixed with cyanoacrylate, (2) antibacterial mesh fixed with sutures, and (3) antibacterial mesh fixed with cyanoacrylate (n = 6 each). The implants were inoculated with 106 CFU/mL of S aureus. At 14 days after surgery, bacterial adhesion to the implant and its integration within host tissue were determined through microbiological, histological and immunohistochemical procedures. RESULTS: As observed in vitro, the cyanoacrylate gave rise to a 1.5-cm bacteria-free margin around the prosthetic mesh. In vivo, the tissue adhesive prevented bacterial adhesion to the fixation zones, reducing infection of chlorhexidine-free meshes and optimizing the efficacy of the antibacterial meshes compared with those fixed with sutures. CONCLUSION: These findings indicated that cyanoacrylate fixation does not affect mesh integration into the host tissue. Likewise, the antibacterial behavior and tissue response of a chlorhexidine-treated polypropylene mesh is improved when cyanoacrylate is used for its fixation.

Development of Biocomposite Polymeric Systems Loaded with Antibacterial Nanoparticles for the Coating of Polypropylene Biomaterials.

The development of a biocomposite polymeric system for the antibacterial coating of polypropylene mesh materials for hernia repair is reported. Coatings were constituted by a film of chitosan containing randomly dispersed poly(d,l-lactide-co-glycolide) (PLGA) nanoparticles loaded with chlorhexidine or rifampicin. The chlorhexidine-loaded system exhibited a burst release during the first day reaching the release of the loaded drug in three or four days, whereas rifampicin was gradually released for at least 11 days. Both antibacterial coated meshes were highly active against Staphylococcus aureus and Staphylococcus epidermidis (106 CFU/mL), displaying zones of inhibition that lasted for 7 days (chlorhexidine) or 14 days (rifampicin). Apparently, both systems inhibited bacterial growth in the surrounding environment, as well as avoided bacterial adhesion to the mesh surface. These polymeric coatings loaded with biodegradable nanoparticles containing antimicrobials effectively precluded bacterial colonization of the biomaterial. Both biocomposites showed adequate performance and thus could have potential application in the design of antimicrobial coatings for the prophylactic coating of polypropylene materials for hernia repair.

Sleeve Gastrectomy and Gastric Bypass Decrease the Carotid Intima-Media Thickness in Obese Men: Association with Weight Loss, Cardiovascular Risk Factors, and Circulating Testosterone.

BACKGROUND: Obesity surgery has shown to decrease the carotid intima-media thickness (IMT), but studies that compare different surgical techniques are scarce, especially in men. OBJECTIVE: To evaluate the changes in IMT in men after laparoscopic Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG) and its association with circulating testosterone. SETTING: Academic Hospital. METHODS: We studied 40 men with severe obesity, of whom 20 were submitted to laparoscopic RYGB and 20 to SG. Twenty control men matched for age and degree of obesity were also included. Both patients and controls were evaluated at baseline and 6 months after surgery or conventional treatment with diet and exercise, respectively. RESULTS: The mean carotid IMT decreased after surgery irrespective of the surgical technique whereas no changes were observed in the control men submitted to conventional therapy (Wilks' λ = 0.745, P < 0.001 for the interaction, P < 0.001 for RYGB vs. controls, P = 0.001 for SG vs. controls, P = 0.999 for RYGB vs. SG). The decrease in the carotid IMT correlated with the increase in total testosterone (r = 0.428, P = 0.010) and lost BMI (r = 0.486, P < 0.001). Multivariate linear regression retained only the decrease in BMI (ß = 0.378, P = 0.003) after adjustment (R2 = 0.245, F = 9.229, P = 0.001). CONCLUSION: Both RYGB and SG decrease carotid IMT in men with obesity compared with conventional treatment with diet and exercise.

Preclinical bioassay of a novel antibacterial mesh for the repair of abdominal hernia defects.

BACKGROUND: In hernia surgery, soaking of meshes in antibiotics before implantation is a prophylactic strategy for minimizing the risk of infection while providing minimal, local, drug doses. This study describes the development and application of an antibacterial mesh coating comprising a carboxymethylcellulose gel loaded with rifampicin in a preclinical model of Staphylococcus aureus and S. epidermidis infection in rabbits. METHODS: Antibacterial activity and cytocompatibility (with fibroblasts) of unloaded carboxymethylcellulose gel and 0.13 mg/mL rifampicin-carboxymethylcellulose gel were assessed in vitro. Then, partial abdominal wall defects (5 × 2 cm) were created in New Zealand white rabbits (n = 34), the wound inoculated with 0.25 mL of 106 CFU Staphylococcus aureus/ S. epidermidis (n = 17 each), and the defect then repaired with a lightweight, monofilament, large pore polypropylene mesh either uncoated (n = 3) or coated with carboxymethylcellulose gel (n = 7) or rifampicin-carboxymethylcellulose gel (n = 7). By postoperative day 14, coating performance was evaluated by determining bacterial adhesion (via sonication), host tissue incorporation (via histology), macrophage response via immunostaining), and bloodstream drug diffusion (via high-performance liquid chromatography). RESULTS: In vitro, rifampicin-carboxymethylcellulose gel demonstrated great activity against Staphylococcus aureus/S. epidermidis, while being innocuous for fibroblasts. In vivo, rifampicin-carboxymethylcellulose gel-coated implants displayed full bacterial clearance and optimal tissue integration, irrespective of the strain of Staphylococcus. In contrast, uncoated and carboxymethylcellulose gel-coated implants exhibited macro/microscopic signs of infection and impaired tissue integration. Macrophage responses were less in rifampicin-carboxymethylcellulose gel implants than in uncoated mesh (Staphylococcus aureus/S. epidermidis; P < .01) and carboxymethylcellulose gel (S. epidermidis; P < .05) implants. Bloodstream levels of rifampicin were undetectable. CONCLUSION: Soaking meshes in rifampicin-carboxymethylcellulose gel inhibited effectively the bacterial adhesion to the mesh without compromising the tissue repair. This antibiotic gel constitutes an easy-to-use and effective prophylactic strategy that potentially reduce the prevalence of postoperative mesh infection.

Mesh Fixation Using a Cyanoacrylate Applied as a Spray Improves Abdominal Wall Tissue Repair.

BACKGROUND: Tissue adhesives are a feasible option to fix a hernia repair mesh, avoiding tissue trauma of suture fixation. Classically, they are applied in the form of a drop, although novel applications such as spray are emerging. This study compares the use of a new experimental cyanoacrylate (n-butyl) in the form of a spray or drops. MATERIALS AND METHODS: Three study groups of New Zealand White rabbits were established (n = 6 each) according to the method used to fix a 5 × 3 cm polypropylene mesh in a partial abdominal wall defect model: control group (polypropylene stitches), adhesive drops group, and adhesive spray group. Morphological, immunohistochemical, and biomechanical strength studies were performed at 14 d postimplant. Collagen 1/3 gene ratio was determined by quantitative reverse transcription polymerase chain reaction. RESULTS: In the drops group, the adhesive obstructed the mesh pores and prevented tissue infiltration at the points of application. When the adhesive was applied as a spray, although more numerous, adhesive deposits were smaller and allowed for better host tissue infiltration into the mesh. The inflammatory response was similar in the adhesive groups and more intense than in the control group. Collagen 1/3 mRNA ratio was significantly higher in the spray than the control group. The mechanical resistance of the meshes was similar in all three groups. CONCLUSIONS: The application of the cyanoacrylate adhesive in the form of spray to fix polypropylene meshes in an animal model had a similar inflammatory response compared with droplet application. Neither application impacted the mechanical strength of the repaired area. An increased in collagen 1/3 ratio was found with cyanoacrylate spray compared with suture, and future studies should focus on this pathway.

Assessment of short-term outcome with TiO2 mesh in laparoscopic repair of large paraesophageal hiatal hernias.

BACKGROUND: Laparoscopic large para-oesophageal hiatal hernia (LPHH) repair using mesh reinforcement significantly reduces postoperative recurrence rates compared to conventional suture repair, especially within short follow-up times. However, the ideal strategy for repairing LPHH remains disputable because no clear guidelines are given regarding indications, mesh type, shape or position. The aim of this study was to survey our short-term results of LPHH management with a biosynthetic monofilament polypropylene mesh coated with titanium dioxide to enhance biocompatibility (TiO2Mesh™). METHODS: A retrospective study was performed at Ramon y Cajal University Hospital, Spain from December 2014 to October 2018. Data were collected on 27 consecutive patients with extensive hiatal hernia defects greater than 5 cm for which a laparoscopic repair was performed by primary suture and additional reinforcement with a TiO2Mesh™. Study outcomes were investigated, including clinical and radiological recurrences, dysphagia and mesh-related drawbacks. RESULTS: Twenty-seven patients were included in our analysis; 10 patients were male, and 17 were female. The mean age was 73 years (range, 63-79 years). All operations were performed laparoscopically. The median postoperative hospital stay was 3 days. After a mean follow-up of 18 months (range, 8-29 months), only 3 patients developed clinical recurrence of reflux symptoms (11%), and 2 had radiological recurrences (7%). No mesh-related complications occurred. CONCLUSIONS: TiO2Mesh™ was found to be safe for laparoscopic repair of LPHH with a fairly low recurrence rate in this short-term study. Long-term studies conducted over a period of years with large sample sizes will be essential for confirming whether this mesh is suitable as a standard method of care with few drawbacks.

Comparing the influence of two immunosuppressants (fingolimod, azathioprine) on wound healing in a rat model of primary and secondary intention wound closure.

In this study, rat models of wound closure by first and second intention were developed to evaluate the influence that two immunosuppressants for treating multiple sclerosis (fingolimod, azathioprine) have on wound healing. Sixty-three Sprague-Dawley rats were daily treated with fingolimod (0.6 mg/kg), azathioprine (2.5 mg/kg), or placebo (saline). Following 6 weeks of treatment, a linear incision (1.5 cm) or a circular excisional defect (diameter 1.5 cm) was made on the dorsal skin. The treatments were uninterrupted and after 7 days (incisional) or 21 days (incisional, excisional), animals were euthanized (n = 7 per group and time-point). Morphometric (wound closure), histological (stainings), and immunofluorescent studies (macrophages) were performed to evaluate the healing process. For both the incisional and excisional defects, animals treated with fingolimod exhibited a healing process equivalent to that of placebo in terms of collagenization, wound closure, and macrophage response. By comparison, groups treated with azathioprine displayed a delay in healing times which was especially evident in the excisional defect, where inflammatory reaction and collagen deposition in the repair tissue remained active by day 21. These results show that immunosuppressants with a selective mechanism of action (fingolimod) can have less impact on wound healing than their classical nonselective counterparts (azathioprine).

Redo Surgery after Failure of Antireflux Surgery.

Surgery for refractory gastroesophageal reflux disease (GERD) has a satisfactory outcome for most patients; however, sometimes redo surgery is required. The Outcome and morbidity of a redo are suggested to be less successful than those of primary surgery. The aim of this study was to describe our experience, long-term results, and complications in redo surgery. From 2000 to 2016, 765 patients were operated on for GERD at our hospital. A retrospective analysis of 56 patients (7.3%) who underwent redo surgery was conducted. Large symptomatic recurrent hiatal hernia (50%) and dysphagia (28.6%) were the most frequent indications for redo. An open approach was chosen in 64.5 per cent of patients. Intraoperative and postoperative complication rates were 18 per cent and 14.3 per cent, respectively. Mortality rate was 1.8 per cent. Symptomatic outcome was successful in 71.4 per cent. Patients reoperated because of dysphagia and large recurrent hiatal hernia had a significantly higher failure rate (32.3% and 31.2%, respectively; P = 0.001). Complication rate was significantly lower in the laparoscopic group (0% vs 22.2%; P = 0.04). There were no statistical differences between expert and nonexpert surgeons. Laparoscopic approach has increased to 83.3 per cent in the last five years. Symptomatic outcome after redo surgery was less satisfactory than that after primary surgery. Complications were lower if a minimally invasive surgical approach was used.

Serum Bioavailable Vitamin D Concentrations and Bone Mineral Density in Women After Obesity Surgery.

INTRODUCTION: Low bone mass after obesity surgery may arise as a consequence of chronic malabsorption of calcium and vitamin D. However, we have not found any role of serum 25-hydroxyvitamin D or of polymorphisms in the vitamin D receptor gene in previous studies. PURPOSE: To investigate the circulating bioavailable 25-hydroxyvitamin D in women after bariatric procedures and its association with bone mass. PATIENTS AND METHODS: The study consisted of 91 women on follow-up for 7 ± 2 years after bariatric surgery. We measured bone mineral density (BMD), serum parathormone (PTH), 25-hydroxyvitamin D, and vitamin D binding protein (VDBP). All patients were genotyped for two variants in the coding region of VDBP (rs4588 and rs7041). Bioavailable 25-hydroxyvitamin D was calculated in double homozygotes. RESULTS: We found a negative correlation between bioavailable 25-hydroxyvitamin D and PTH (r = -0.373, P = 0.018), but not with BMD at lumbar spine (r = -0.065, P = 0.682) or hip (r = -0.029, P = 0.857). When adjusting by age, similar results were found for PTH (r = -0.441, P = 0.005), BMD at lumbar spine (r = -0.026, P = 0.874) and hip (r = -0.096, P = 0.561). After multivariate linear regression, forcing bioavailable 25-hydroxyvitamin D into the model resulted in a weak significant association with BMD at the lumbar spine (ß = - 0.247, P = 0.025). CONCLUSIONS: Serum bioavailable 25-hydroxyvitamin D concentrations are not associated with bone mass loss after bariatric surgery in women. The negative association with serum PTH levels suggests that vitamin D supplementation partly improves secondary hyperparathyroidism, yet other mechanisms may contribute to low bone mass after bariatric surgery.

Comparative study between open and minimally invasive approach in the surgical management of esophageal leiomyoma.

INTRODUCTION: Leiomyomas are the most common benign tumors of the esophagus. Although classically surgical enucleation through thoracotomy or laparotomy has been widely accepted as treatment of choice, development of endoscopic and minimally invasive procedures has completely changed the surgical management of these tumors. MATERIAL AND METHODS: We performed a retrospective review of all esophageal leiomyoma operated at Hospital Universitario Ramón y Cajal (Madrid, Spain) between January 1986 and December 2014, analyzing patients' demographic data, symptomatology, tumor size and location, diagnostic tests, surgical data, complications and postoperative stay. RESULTS: Thirteen patients were found within that period, 8 men and 5 women, with a mean age of 53.62 years (range 35-70 years). Surgical enucleation was achieved in all patients. In 8 cases (61.54%) a thoracic approach was performed (4 thoracotomies and 4 thoracoscopies), and in 5 cases (38.56%) an abdominal approach was performed (3 laparotomies and 2 laparoscopies); enucleation was carried out through a minimally invasive approach in 6 patients (46.15%). There were no cases of endoscopic resection alone. Surgery mean length was 174.38 minutes (range 70-270 minutes) and median postoperative stay was 6.5 days (range 2-27 days). There was neither mortality nor cases of intraoperative complications were described. No postoperative major complications were reported; however one patient presented important pain in his right hemithorax that required management and long term follow-up by the Pain Management Unit. With a mean follow-up of 165.57 months (median 170; range 29-336 months) no recurrences were reported. CONCLUSION: Enucleation is the treatment of choice for the majority of esophageal leiomyomas. In our experience, duration of the surgical procedure through minimally invasive approach was longer than surgery through open approach; however, postoperative stay was shorter in the first group. Paradoxically, incision pain after surgery (thoracic neuralgia) was found to be higher in the minimally invasive approach group. Nevertheless, none of the results obtained in the study reached statistical significance, probably due to the small simple size.

Duodenal fistula after gastrectomy: Retrospective study of 13 new cases.

INTRODUCTION: Duodenal stump fistula (DSF) after gastrectomy has a low incidence but a high morbidity and mortality, and is therefore one of the most aggressive and feared complications of this procedure. MATERIAL AND METHODS: We retrospectively evaluated all DSF occurred at our hospital after carrying out a gastrectomy for gastric cancer, between January 1997 and December 2014. We analyzed demographic, oncologic, and surgical variables, and the evolution in terms of morbidity, mortality and hospital stay. RESULTS: In the period covered in this study, we performed 666 gastrectomies and observed DSF in 13 patients (1.95%). In 8 of the 13 patients (61.5%) surgery was the treatment of choice and in 5 cases (38.5%) conservative treatment was carried out. Postoperative mortality associated with DSF was 46.2% (6 cases). In the surgical group, 3 patients developed severe sepsis with multiple organ failure, 2 patients presented a major hematemesis which required endoscopic haemostasis, 1 patient had an evisceration and another presented a subphrenic abscess requiring percutaneous drainage. Six patients (75%) died despite surgery, with 3 deaths in the first 24 hours of postoperative care. The 2 patients who survived after the second surgical procedure had a hospital stay of 45 and 84 days respectively. In the conservative treatment group the cure rate was 100% with no significant complications and an average postoperative hospital stay of 39.5 days (range, 26-65 days). CONCLUSION: FMD is an unusual complication but it is associated with a high morbidity and mortality. In our experience, conservative management has shown better results compared with surgical treatment.

The role of serum osteoprotegerin and receptor-activator of nuclear factor-κB ligand in metabolic bone disease of women after obesity surgery.

Metabolic bone disease may appear as a complication of obesity surgery. Because an imbalance in the osteoprotegerin and receptor-activator of nuclear factor-κB ligand system may underlie osteoporosis, we aimed to study this system in humans in the metabolic bone disease occurring after obesity surgery. In this study we included sixty women with a mean age of 47 ± 10 years studied 7 ± 2 years after bariatric surgery. The variables studied were bone mineral density, ß-isomer of C-terminal telopeptide of type I collagen cross-links (a bone resorption marker), the bone formation markers osteocalcin and N-terminal propeptide of procollagen 1, serum osteoprotegerin and receptor-activator of nuclear factor-κB ligand. Serum osteoprotegerin inversely correlated with the bone remodeling markers osteocalcin, ß-isomer of C-terminal telopeptide of type I collagen cross-links and N-terminal propeptide of procollagen 1. The osteoprotegerin and receptor-activator of nuclear factor-κB ligand ratio also correlated inversely with serum parathormone and osteocalcin. Bone mineral density at the lumbar spine was associated with age (ß = -0.235, P = 0.046), percentage of weight loss (ß = 0.421, P = 0.001) and osteoprotegerin and receptor-activator of nuclear factor-κB ligand ratio (ß = 0.259, P = 0.029) in stepwise multivariate analysis (R 2 = 0.29, F = 7.49, P < 0.001). Bone mineral density at the hip site was associated only with percentage of weight loss (ß = 0.464, P < 0.001) in stepwise multivariate regression (R 2 = 0.21, F = 15.1, P < 0.001). These data show that the osteoprotegerin and receptor-activator of nuclear factor-κB ligand system is associated with bone markers and bone mineral density at the lumbar spine after obesity surgery.

Preclinical Bioassay of a Polypropylene Mesh for Hernia Repair Pretreated with Antibacterial Solutions of Chlorhexidine and Allicin: An In Vivo Study.

INTRODUCTION: Prosthetic mesh infection constitutes one of the major complications following hernia repair. Antimicrobial, non-antibiotic biomaterials have the potential to reduce bacterial adhesion to the mesh surface and adjacent tissues while avoiding the development of novel antibiotic resistance. This study assesses the efficacy of presoaking reticular polypropylene meshes in chlorhexidine or a chlorhexidine and allicin combination (a natural antibacterial agent) for preventing bacterial infection in a short-time hernia-repair rabbit model. METHODS: Partial hernia defects (5 x 2 cm) were created on the lateral right side of the abdominal wall of New Zealand White rabbits (n = 21). The defects were inoculated with 0.5 mL of a 106 CFU/mL Staphylococcus aureus ATCC25923 strain and repaired with a DualMesh Plus antimicrobial mesh or a Surgipro mesh presoaked in either chlorhexidine (0.05%) or allicin-chlorhexidine (900 µg/mL-0.05%). Fourteen days post-implant, mesh contraction was measured and tissue specimens were harvested to evaluate bacterial adhesion to the implant surface (via sonication, S. aureus immunolabeling), host-tissue incorporation (via staining, scanning electron microscopy) and macrophage response (via RAM-11 immunolabeling). RESULTS: The polypropylene mesh showed improved tissue integration relative to the DualMesh Plus. Both the DualMesh Plus and the chlorhexidine-soaked polypropylene meshes exhibited high bacterial clearance, with the latter material showing lower bacterial yields. The implants from the allicin-chlorhexidine group displayed a neoformed tissue containing differently sized abscesses and living bacteria, as well as a diminished macrophage response. The allicin-chlorhexidine coated implants exhibited the highest contraction. CONCLUSIONS: The presoaking of reticular polypropylene materials with a low concentration of chlorhexidine provides the mesh with antibacterial activity without disrupting tissue integration. Due to the similarities found with the antimicrobial DualMesh Plus material, the chlorhexidine concentration tested could be utilized as a prophylactic treatment to resist infection by prosthetic mesh during hernia repair.

Inhibition of Staphylococcus aureus Adhesion to the Surface of a Reticular Heavyweight Polypropylene Mesh Soaked in a Combination of Chlorhexidine and Allicin: An In vitro Study.

INTRODUCTION: Presoaking meshes for hernia repair with antiseptics prior to implantation could decrease the adhesion of microorganisms to the material surface and reduce the risk of antibiotic resistances. In this work, we evaluate chlorhexidine and allicin (natural antiseptic not yet tested for these purposes) against vancomycin as antiseptics to be used in the pretreatment of a heavyweight polypropylene mesh using an in vitro model of bacterial contamination. METHODS: Solutions of saline, vancomycin (40 µg/mL), allicin (1,000 µg/mL), chlorhexidine (2%-0.05%) and the combination allicin-chlorhexidine (900 µg/mL-0.05%) were analyzed with agar diffusion tests in the presence of 106 CFU Staphylococcus aureus ATCC25923. Additionally, sterile fragments of Surgipro (1 cm2) were soaked with the solutions and cultured onto contaminated agar plates for 24/48/72 h. The antimicrobial material DualMesh Plus was utilized as positive control. At every time, the inhibition zones were measured and the bacterial adhesion to the mesh surface quantified (sonication, scanning electron microscopy). Cytotoxicity of the treatments was examined (alamarBlue) using rabbit skin fibroblasts. RESULTS: The largest zones of inhibition were created by allicin-chlorhexidine. Chlorhexidine was more effective than vancomycin, and allicin lost its effectiveness after 24 h. No bacteria adhered to the surface of the DualMesh Plus or the meshes soaked with vancomycin, chlorhexidine and allicin-chlorhexidine. On the contrary, saline and allicin allowed adherence of high loads of bacteria. Vancomycin had no toxic effects on fibroblasts, while allicin and chlorhexidine exerted high toxicity. Cytotoxicity was significantly reduced with the allicin-chlorhexidine combination. CONCLUSIONS: The use of antiseptics such as chlorhexidine, alone or combined with others like allicin, could represent an adequate prophylactic strategy to be used for hernia repair materials because soaking with these agents provides the mesh with similar antibacterial properties to those observed after soaking with vancomycin, similar to the effect of DualMesh Plus.

Comparing the host tissue response and peritoneal behavior of composite meshes used for ventral hernia repair.

BACKGROUND: The use of a prosthetic material is the best treatment option for ventral hernia repair; one of the most frequently performed abdominal surgery procedures. This preclinical study compares the behavior of a new mesh (Parietex composite ventral patch [Ptx]) with that of two existing meshes used for ventral hernia repair. MATERIALS AND METHODS: Fifty-four New Zealand White rabbits (3000 g) were used in an experimental model of umbilical hernia repair (diameter 1.5 cm). The materials tested were: Ventralex ST hernia patch (Vent) (Bard Davol Inc, Warwick, RI) (n = 18); Proceed ventral patch (Ethicon, Somerville, NJ) (PVP) (n = 18) and Ptx (Covidien, Sofradim, Trevoux, France) (n = 18). At 3, 7, 14 d, and 6 wk after implant, peritoneal behavior and adhesion formation were assessed by sequential laparoscopy. Mesh mesothelial cover was determined by scanning electron microscopy. Host tissue ingrowth (collagens I and III) and the macrophage response were assessed by immunohistochemical labeling. Animals were euthanized at 2, 6 wk, and 6 mo after surgery. Data were compared using the Mann-Whitney U test. RESULTS: Adhesion formation from 3 d-6 wk was significantly greater (P < 0.05) for PVP compared with Vent or Ptx. Three encapsulated PVP implants showed "tissue-integrated" adhesions affecting the intestinal loops. All three implant types showed similar patterns of collagen l and III deposition. The PVP mesh elicited the greater macrophage response both at 2 wk and 6 mo. CONCLUSIONS: Ptx and Vent showed excellent mesothelialization, which led to minimum adhesion formation. The appropriate tissue integration of Ptx in the parietal neoperitoneum is likely attributable to its deployment system.

Effects of bariatric surgery on male obesity-associated secondary hypogonadism: comparison of laparoscopic gastric bypass with restrictive procedures.

Bariatric surgery results in the complete resolution of male obesity-associated secondary hypogonadism (MOSH) in many patients. However, the effects of different bariatric surgical procedures on male sexual hormone profiles and sexual dysfunction have not been compared to date. We compared the pre- and post-operative (at least 6 months after initial surgery) sex hormone profiles of 20 severely obese men submitted to laparoscopic gastric bypass (LGB) with 15 similar patients submitted to restrictive techniques (sleeve gastrectomy in 10 and adjustable gastric banding in 5). We calculated free testosterone (FT) levels from total testosterone (TT) and sex hormone binding globulin (SHBG) concentrations. Fasting glucose and insulin levels served for homeostatic model assessment of insulin resistance (HOMAIR). MOSH was present in 25 and 16 of the 35 patients when considering TT and FT concentrations respectively, resolving after surgery in all but one of them. When considering all obese men as a whole, patients submitted to LGB or restrictive procedures did not differ in terms of excess weight loss, in the decrease of fasting glucose and insulin, HOMAIR and waist circumference, or in the increase of serum 25-hydroxyvitamin D, TT and FT levels. The improvement in TT correlated with the decrease in fasting glucose (r = -0.390, P = 0.021), insulin (r = -0.425, P = 0.015) and HOMAIR (r = -0.380, P = 0.029), and with the increase in SHBG (r = 0.692, P < 0.001). The increase in FT correlated with the decrease in fasting glucose (r = -0.360, P = 0.034). LGB and restrictive techniques are equally effective in producing a remission of MOSH.

Pancreaticoduodenectomy for metastasis of uterine leiomyosarcoma to the pancreas.

Metastasis of uterine leiomyosarcoma to the pancreas is rare. A 46-year-old woman was diagnosed with uterine leiomyosarcoma and underwent surgery. Thereafter, recurrences in the lung and subsequently in the pancreas were diagnosed. These lesions were resected and diagnosed as metastasis of uterine leiomyosarcoma. We report a rare case of uterine leiomyosarcoma with metastasis to the lung and pancreas, both of which were resected using aggressive surgery.