[Biomarkers of system inflammation in local and diffuse peritonitis]. / Markery sistemnogo vospaleniia pri mestnom i rasprostranennom peritonite.

In cases of any acute surgical abdominal disease the progression of purulent inflammation can lead to local or diffuse peritonitis. The indicators of the degree and specificity of the inflammatory response in blood such as cytokine concentration, neutrophil activity, plasma antioxidant capacity (thiols concentration) could be considered as potential predictors of complications. The luminol-dependent chemiluminescence (CL) response of blood activated by the phorbol ester (PMA), and the concentration of cytokines IL-6, IL-8, IL-10, myeloperoxidase (MPO) and thiols in plasma were measured in patients with uncomplicated condition (group 1, n=8), local peritonitis (group 2, n=9) or diffuse peritonitis (group 3, n=9) at admission to surgery (before surgical operation, b/o), immediately after surgical operation (a/o) and a day after surgery (1 day) as well as in healthy volunteers (norm, n=12). In all time-points the cytokines and MPO concentrations measured by ELISA, in group 3 were higher than in healthy volunteers and in patients in groups 1 and 2. Blood CL demonstrated a more than 5-fold increase above the normal values in all patients, and was also higher in group 2 as compared to group 1 (b/o and a/o). Patients in group 3 had shown both maximum and minimum of CL values, which could be a consequence of neutrophil priming or exhaustion ("immune paralysis"), respectively. The same patients' plasma exhibited low thiol concentration (≤30% vs normal values). In patients with fatal outcomes (group 3, n=2) within a day after surgery, either a decrease of the CL to zero values concurrently with elevated IL-8 and IL-6 concentrations and low thiol levels was observed, or CL exceeded normal values more than 20 times with concurrent complete exhaustion of the plasma thiol pool. No clear dependency between the plasma parameters and neutrophil activity was found. Hence a parameter set for prognosis and/or early diagnosis of infectious complications in acute abdominal pathology should include different biomarkers of the inflammatory response: cytokine profile (IL-6, IL-8, IL-10), MPO and neutrophil activity, antioxidant plasma capacity (e.g., total thiols concentration).

[Diagnostic and treatment approaches for acute appendicitis in the Russian Federation. Results of the all-Russian survey]. / Diagnosticheskie i lechebnye podkhody pri ostrom appenditsite v praktike khirurgov Rossiiskoi Federatsii. Rezul'taty obshcherossiiskogo oprosa.

OBJECTIVE: To improve treatment outcomes in patients with acute appendicitis (AA). MATERIAL AND METHODS: An internet survey was performed. Questionnaire consisted of 15 questions concerning diagnosis and treatment of AA: application of prognostic scales, incidence and technical aspects of laparoscopic appendectomy (LA), antibiotic prophylaxis, postoperative management, compliance with international and national clinical guidelines. A total of 690 questionnaires were received and analyzed (3.67% of all surgeons in the Russian Federation). RESULTS: Eighteen percent of respondents use at least one prognostic scale. The vast majority of surgeons (92%) use antibiotic prophylaxis. Almost half of respondents place trocars in the triangulation position (44%), one third of surgeons ligate the mesentery of the appendix (35%), most respondents perform mesoappendectomy (60%) with monopolar and bipolar cautery. Forty-five percent of all respondents do not invert the appendix stump. Significant number of respondents use abdominal drainage routinely. Only 3.5% of surgeons use multimodal postoperative analgesia. Less than 22% of patients are operated under low-pressure pneumoperitoneum. Standardization of surgical technique and perioperative approaches including those specified in the guidelines is absent. We also found insufficient awareness of surgeons about international and national clinical guidelines. CONCLUSION: This study may be useful for standardizing treatment approaches, choosing the best practice, popularizing and improving of current clinical guidelines.

[Laparoscopic surgery for advanced appendicular peritonitis]. / Laparoskopicheskaya khirurgiya rasprostranennogo appendikulyarnogo peritonita.

OBJECTIVE: To evaluate the results of laparoscopic treatment of patients with advanced appendicular peritonitis. MATERIAL AND METHODS: There were 271 patients with acute appendicitis complicated by peritonitis. The main group consisted of patients who underwent laparoscopic appendectomy after diagnostic laparoscopy (n=231), the control group - diagnostic laparoscopy followed by conversion to median laparotomy (n=36). Four extremely ill patients were operated through laparotomy and excluded from the further analysis. RESULTS: Diagnostic laparoscopy was performed in 267 patients with advanced appendicular peritonitis. Laparoscopic appendectomy, debridement and abdominal drainage were performed in 231 (85.2%) patients. Mean age of patients was 44±18.5 years, duration of disease - 36.2±20.3 hours. Diffuse peritonitis was diagnosed in 219 (82%) patients, advanced peritonitis - in 48 (16.5%) cases. Incidence of conversion was 13.5%. Mortality was absent in both groups. Postoperative morbidity was significantly higher in the conversion group (72.2% vs. 29.4%, p<0.0001). CONCLUSION: Laparoscopic interventions for common appendicular peritonitis are feasible, effective and reduce postoperative morbidity.

Development and evaluation of a novel simulation model for transabdominal preperitoneal (TAPP) inguinal hernia repair.

BACKGROUND: Transabdominal preperitoneal (TAPP) inguinal hernia repair requires the surgeon to have good manual skills in laparoscopic surgery, as well as an understanding of the laparoscopic features of the groin anatomy. This is why TAPP is considered a more difficult surgical procedure compared to open techniques. Realistic training model for TAPP inguinal hernia repair would enhance surgeons' skills before they enter in the operation room. Our aim was to create a realistic, inexpensive, and easily reproducible model for laparoscopic TAPP inguinal hernia repair and to assess its effectiveness. METHODS: The applied TAPP inguinal hernia repair training simulator consists of a laparoscopic box and an inguinal region model placed in it. The model of the groin area is made of the porcine stomach and assembling materials. Uniaxial tensile and T-peel tests were performed to compare the mechanical properties of the porcine stomach and the human cadaver peritoneum. Thirty eight surgeons performed TAPP inguinal hernia repair using this model. Their opinions were scored on a five-point Likert scale. RESULTS: Close elastic modules of the porcine and human tissues (13.5 ± 4.2 kPa vs. 15.8 ± 6.7 kPa, p = 0.531) gave to trainees a realistic tissue feel and instrument usage. All participants strongly agreed that model was highly useful for TAPP inguinal hernia repair training. They also put the following points: the model as a whole 5 (3-5), simulation of anatomy 5 (3-5), simulation of dissection and mobilization 5 (3-5), and simulation of intracorporeal suture 5 (4-5). CONCLUSIONS: We successfully created a model for TAPP inguinal hernia repair training. The model is made of inexpensive synthetic and biological materials similar to the human tissue. The model is easy to reproduce and can be used in the training programs of surgical residents.

[Fast-track rehabilitation for acute cholecystitis: intermediate outcomes of prospective randomized trial]. / Uskorennoe vyzdorovlenie pri ostrom kholetsistite: promezhutochnye rezul'taty prospektivnogo randomizirovannogo issledovaniia.

AIM: To analyze an efficacy of FT-protocol in patients with acute cholecystitis. MATERIAL AND METHODS: Prospective randomized study included 102 patients (45 of main group (FT) and 57 of control groups). Patients did not differ by TG13 severity index. The protocol included information, antibiotic prophylaxis, restriction of drainage, intraperitoneal anesthesia with long-term anesthetics, low pressure pneumoperitoneum, antiemetics in the presence of risk factors, early activation and feeding of the patient. Pain was assessed by VAS immediately after surgery, and 2, 6 and 12-24 hours postoperatively. RESULTS: Surgery time was similar in both groups. Need for anesthesia and pain severity were significantly lower in the FT group. A total absence of pain (VAS 0-1) on the 1st postoperative day was noted in 8 (17.7%) of the FT group and 2 (3.5%) patients of the control group (p=0.038). Shoulder pain developed in 4 (8.9%) cases of the main and 22 (38.6%) cases of the control group (p=0.001). Postoperative nausea developed in 13% of the FT group vs 40.5% in the control group (p=0.05). Hospital-stay was 1.29±0.7 days and 2.7±1.6 (p<0.0001), respectively. The time of the first stool was similar. Twenty-four (53.5%) patients of the FT group and 8,9% of the control group were discharged on 1st postoperative day. There were 2 (IIIA) complications in the main group and 3 - in the control group (IIIA, IIIB and IV). There were no mortality and readmissions. CONCLUSION: FT protocol in AC reduce postoperative pain, dyspepsia, shoulder pain and in-hospital stay with equal number of postoperative complications.

[Comparison of standard and fast track rehabilitation in patients with acute appendicitis. Intermediate results of multicenter prospective randomized trial]. / Sravnitel'naia otsenka metodov standartnoi i uskorennoi reabilitatsii bol'nykh s ostrym appenditsitom. Promezhutochnye rezul'taty mnogotsentrovogo prospektivnogo randomizirovannogo issledovaniia.

AIM: To analyze outcomes of fast track rehabilitation in patients with acute appendicitis. MATERIAL AND METHODS: Prospective, randomized multi-center trial including 86 patients was conducted. There were 38 patients in the main group and 48 in the control group. All patients underwent laparoscopic appendectomy under endotracheal anesthesia. Protocol included informing, no premedication, glucose infusion prior to surgery, antibiotics administration, mesoappendix excision, limited deployment of drainage tubes, intraabdominal prolonged anesthesia, minimal pneumoperitoneum, limited irrigation, minimum power monopolar electrocautery, antiemetics, early activation and eating (2 and 6 hours after surgery). Pain was evaluated by visual-analogue scale. Auscultative peristalsis was considered every 2 hours after surgery. Cortisol level was assessed preoperatively, in 6 and 12-24 hours after surgery in 11 (29%) and 15 (31%) patients of the main and control groups respectively. Discharge criteria: no leukocytosis, fever and pain syndrome requiring anesthesia, no signs of complications and patient's consent. RESULTS: Terms of disease, gender, age and comorbidities were similar in all patients. Duration of surgery under minimal pneumoperitoneum and standard pressure was also similar: 69.2±3.98 and 70.9±3.89 min (p=0.762). Pain syndrome grade and need for analgesics were significantly lower in the main group within entire follow-up. Pain syndrome was absent at the 1st postoperative day in 16 (42%) and 2 (4.1%) patients of both groups, respectively (score 0-1). Phrenic nerve syndrome was observed in 36.8% of the main group and 60.4% of the control group (p=0.05). Incidence of dyspepsia and terms of peristalsis onset were similar. Length of hospital-stay was 1.45 days in the main group and 3.15 days in the control group (p=0.002). In the main group 18 (47%) patients were discharged on the first day after surgery. There were only 4 (8.3%) patients with similar hospital-stay in the control group (p<0.001). There were no repeated hospitalizations. Postoperative cortisol concentration was similar in both groups as well as in complicated and uneventful postoperative period. In the main group postoperative intestinal paresis (Clavien-Dindo grade 2) occurred in 1 patient. In the control group 7 patients had postoperative infiltrate and 1 patient - intestinal paresis (Clavien-Dindo grade 2). Postoperative drainage tube was deployed in 3 out of 7 patients with postoperative infiltrates and 6 of them received antibiotic therapy. Medication was successfully applied in all patients with complications. CONCLUSION: There are some advantages of FTR for AA including reduced pain syndrome, morbidity and less length of hospital-stay. Issue of cortisol concentration requires further trials.

[Optimal time of surgery for acute adhesive small bowel obstruction]. / Vybor sroka operativnogo lecheniia pri ostroi spaechnoi tonkokishechnoi neprokhodimosti (mul'titsentrovoe prospektivnoe randomizirovannoe issledovanie).

AIM: To define optimal terms of surgery for acute adhesive non-strangulatory small bowel obstruction. MATERIAL AND METHODS: The analysis included 703 publications from e-LIBRARI.RU (342 works) and NCBI (361 works) databases for acute adhesive intestinal obstruction. The vast majority of articles presented retrospective analysis of single-center experience. RESULTS: It has been established that short course of medication is predominantly used for acute adhesive intestinal obstruction in the Russian Federation. International studies point 2-5 days for conservative treatment. The advantages and disadvantages of short and long courses of medication were analyzed. Therefore, multicenter, prospective, randomized trial 'Comparison of early operative treatment (12-hour medication) and long-term conservative treatment (48 hours) for acute adhesive small bowel obstruction' (COTACSO) was planned and registered (Unique Protocol ID: 14121729). The study protocol involves clinical, laboratory and instrumental exclusion of strangulation, randomization and conservative treatment of 2 groups of patients for 12 and 48 hours. Patients will undergo surgical interventions if obstruction will be present by that date. The main endpoint is mortality rate in both groups. The end of the study is December 2020.

Comparative Study of Sutureless Fixation of Lightweight Surgical Meshes for Hernia Repair in a Rat Model.

The aim of this study was to compare the efficacy of different methods of sutureless fixation of lightweight meshes made of different polymers for repair of experimental hernias. Two lateral hernia defects were modeled in male rats and covered with polyester and polypropylene prostheses. The meshes were fixed with Histacryl glue (group 1), or self-gripping meshes were used (group 2), or the meshes were implanted without fixation (group 3). On day 5 after surgery, mesh position and efficiency of fixation were evaluated. It was found that fixation is necessary for all light surgical meshes. Polyester meshes demonstrated better adhesive properties than polypropylene meshes. The most pronounced differences in the adhesive properties were found for self-gripping prosthesis, while in the groups with glue fixation, the differences were less pronounced.

Biomechanical compatibility of surgical mesh and fascia being reinforced: dependence of experimental hernia defect repair results on anisotropic surgical mesh positioning.

PURPOSE: We aimed to compare the effectiveness of experimental middle hernia defect repair in regard to the transverse and longitudinal positioning of anisotropic lightweight surgical mesh. METHODS: The mechanical properties of fascial layers and surgical mesh DynaMesh(®)-PP Light were determined in two perpendicular directions under uniaxial tension. In 12 male Wistar rats, middle hernia defect was repaired by the sublay technique. In six animals, the mesh was positioned across (DLH group) and in the other six along (DLV group) the midline. At 6 months after implantation, mesh deformation, structural rearrangement, and repaired abdominal wall biomechanics were evaluated. Histological sections were stained with van Giesen and Mallory's trichrome. RESULTS: The anisotropic mechanical properties of the mesh and fascial layers coincided in the DLH group, but did not correspond to each other in the DLV group. In the DLV group, meshes were stretched in width by 11.4% and reduced in length by 12.7%. In all animals, the lower edge of the mesh was shifted to a defect area with margin hernia formation in two rats. Constant shear stress caused disproportional connective tissue formation. Repaired abdominal wall lost its natural elasticity. In the DLH group, the mesh deformation was minimal. Formed connective tissue was tightly associated with the anterior layer and did not differ from it in composition. The mechanical properties of repaired abdominal wall were close to those of the anterior layer. CONCLUSIONS: In prosthetic hernia repair, the mechanical properties of surgical mesh should correspond with those of the fascia being repaired. A mismatch of mechanical properties may result in implant deformation, abdominal wall biomechanics impairment, and recurrent herniation at the edges of the meshes.

Comet-tail-like inflammatory infiltrate to polymer filaments develops in tension-free conditions.

BACKGROUND: Mesh reinforcement in hiatal hernia repair becomes more frequent but is charged by complications such as erosion or stenosis of the oesophagus. These complications are accompanied by an intense inflammatory infiltrate around the polymer fibres. To characterize this effect, the response to polypropylene fibres in the absence of tension was examined. METHODS: In rats, polypropylene sutures (USP size 1, 3-0 and 7-0) were placed in the subcutis of the abdominal wall without knot or tension. On postoperative days 3, 7 and 21, specimens were excised. The expressions of c-myc, ß-catenin, Notch3, COX-2, CD68 and Ki-67 were measured by immunohistochemistry. RESULTS: In the absence of tension, sutures were surrounded by a foreign body granuloma with an inflammatory infiltrate not encircling the fibre but forming almost symmetric comet-tail-like infiltrates on opposite sides. The expression of c-myc, ß-catenin, Notch3, COX-2, CD68 and Ki-67 was significantly reduced over time in the comet tail, but not in the granuloma. CONCLUSIONS: Even in tension-free conditions, surgical sutures cause a foreign body response with infiltrates of inflammatory cells. This reaction is shaped like a comet tail, and its extension depends on the diameter of the used fibre. Therefore, for reduction of perifilamental infiltrates, not only absence of tension is required, but also a small-sized fibre textile.

Influence of the elasticity module of synthetic and natural polymeric tissue substitutes on the mobility of the diaphragm and healing process in a rabbit model.

Mesh implants are frequently used in congenital diaphragmatic hernia. This experimental study aimed to examine the influence of different materials on the diaphragmatic movement over time as well as their mechanical qualities after 4 months. Ultrapro®, Surgisis®, and Proceed® were implanted onto a diaphragmatic defect in growing rabbits. Diaphragmatic mobility was determined at three time points. At 4 months, defect shrinkage and mechanical properties were measured. The break strength decreased for Ultrapro® and Surgisis®, but did not change relevantly for Proceed®. Ultrapro® (32.46 N/cm) and Proceed® (31.75 N/cm) showed a four-fold higher resistance to tearing than Surgisis® (8.31 N/cm). The elasticity of Ultrapro® showed no significant difference compared to Surgisis® (p = 0.75). Proceed®, on the other hand, was more than twice as elastic as Ultrapro® or Surgisis® (p = 0.015). Ultrapro® had a higher spring rate (6.48 N/mm) compared to Surgisis® (3.82 N/mm) or Proceed® (5.23 N/mm). Observing the standardized movement rates of the diaphragm for each mesh group over time the only statistical differences were seen for the Proceed® group. On account of its material qualities Ultrapro® was found to be the most suitable mesh material for demanding locations in our model.

Comparison of the results of hernia defect plasty with standard and light surgical meshes with identical knitted structure.

Standard and light surgical meshes with identical knitted structure: Parietene Standard/Parietene Light and Premilene/Optilene were chosen for hernioplasty in 20 rats. Six months after surgery, the complications were primarily related to inflammation in groups with implanted standard meshes and with prosthesis deformation in groups with light meshes. The character of complications was determined by characteristics of knitting structure and mechanical proprieties of surgical meshes.

Impact of position of light mesh endoprosthesis with anisotropic structure for the efficiency of anterior abdominal wall reconstruction.

Mechanical testing of light mesh endoprosthesis Ultrapro for tension and bending resistance showed strong anisotropy of the material along and across the loop columns. Ultrapro endoprosthesis was placed parallel and perpendicularly to the midline during plastic repair of a hernial defect in rats. Six months after surgery, the development of hernias and violation of endoprosthesis structure were observed in the group with longitudinal orientation of the endoprosthesis. Transverse orientation of the endoprosthesis led to fortification of the defect site. However, the meshes were in some cases misshapen and formed folds across the loop columns, because of insufficient bending rigidity and elasticity of the material.

Large-pore PDS mesh compared to small-pore PG mesh.

BACKGROUND: Currently, absorbable meshes are used as temporary closure in case of laparostoma. Unfortunately the multifilament polyglycolic acid (PG) meshes with small pores reveal little elasticity acting rather as a fluid barrier than permitting drainage of intra-abdominal fluids. Therefore, a new mesh was constructed of absorbable polydioxanon monofilaments (PDS) with increased porosity and longer degradation time. MATERIAL AND METHODS: For evaluation of the tissue response the new PDS mesh was implanted as abdominal wall replacement in each five rats for 7, 21, or 90 days, respectively, and compared to a PG mesh. Histological analysis included HE staining with measurement of the size of the granuloma and immunoshistochemistry for TUNEL, Ki67, TNF-R2, MMP-2, YB1, FVIII, gas6, AXL. Parameters for neovascularization and nerve ingrowth were analyzed. RESULTS: The inflammatory and fibrotic tissue reaction is attenuated with PDS in comparison to PG, e.g., the size of the granuloma was smaller with less cell turnover, and less remodeling as represented by, e.g., reduction of apoptosis, expression of MMP-2, or TNF-R2. The number of ingrowing nerves and vessels explored via AXL, gas6, and factor VIII was increased in the PDS mesh. CONCLUSION: The results from the present investigation showed that a mesh can be constructed of monofilament PDS that induce significant less inflammatory and fibrotic reaction, however permits fluid drainage and preserves elasticity.

Impact of position of light mesh endoprosthesis with anisotropic structure for the efficiency of anterior abdominal wall reconstruction.

Mechanical testing of light mesh endoprosthesis Ultrapro for stretching and bending resistance showed strong anisotropy of the material along and across the loop columns. Ultrapro endoprosthesis was placed parallel and perpendicularly to the midline during plastic repair of a hernial defect in rats. Six months after surgery, the development of hernias and violation of endoprosthesis structure were observed in the group with longitudinal orientation of the endoprosthesis. Transverse orientation of the endoprosthesis led to fortification of the defect site. However, the meshes were in some cases misshapen and formed folds across the loop columns, because of insufficient bending rigidity and elasticity of the material.

Impact of mesh positioning on foreign body reaction and collagenous ingrowth in a rabbit model of open incisional hernia repair.

BACKGROUND: Incisional hernia remains as one of the most common surgical complications. Different mesh techniques are used in 75-80% of hernia repair. The aim of this study was to evaluate the dependence of mesh positioning and the type of mesh implanted on foreign body reaction and collagenous ingrowth. MATERIALS AND METHODS: In 24 male Chinchilla rabbits, an incisional hernia repair was performed with mesh reinforcement either by sublay (n = 12) or by onlay technique (n = 12). In each group, two different types of mesh prosthesis were investigated: polypropylene (PP, Prolene) and polypropylene-polyglecaprone 25 composite (PP-PG, UltraPro). On postoperative day 60, the inflammatory and connective tissue formation was characterised by measuring the diameter of inner cellular infiltrate and outer fibrous capsule of the foreign body granuloma, and by verifying the collagen type I/III ratio. Furthermore, the expression of matrix metalloproteinase-2 (MMP-2) was analysed. RESULTS: Microscopic investigation of the mesh/host-tissue interface showed typical formation of foreign body granuloma. The diameters of the inner part of the foreign body granuloma representing the amount of inflammatory cell infiltrate were significantly increased in the PP mesh compared to the PP-PG mesh, both in the sublay group (PP 13.1 +/- 1.21 microm vs. PP-PG 11.7 +/- 0.34 microm; P = 0.026) and in the onlay group (PP 13.1 +/- 1.24 microm vs. PP-PG 11.2 +/- 0.55 microm; P = 0.009). The diameter of the fibrous capsule as the outer ring of the granuloma was significantly increased when investigating the PP mesh in sublay position (29.5 +/- 1.12 microm) compared to the PP mesh in onlay position (27.9 +/- 0.73 microm) (P = 0.026). Investigating the quality of perifilamentary collagen deposition expressed as collagen type I/III ratio, the sublay group showed significantly elevated values compared to the onlay group (PP sublay 3.1 +/- 0.18 vs. PP onlay 2.4 +/- 0.41; P = 0.004) (PP-PG sublay 3.5 +/- 0.34 vs. PP-PG onlay 2.6 +/- 0.13; P = 0.002). The analysis of MMP-2 expression revealed no significant differences. CONCLUSION: The beneficial results of mesh reinforcement in the sublay technique might be due to a superior quality of postoperative connective tissue formation. Mesh incorporation, irrespective of positioning, is favourable in low-weight, large, porous mesh material represented by a reduced inflammatory part of the foreign body granuloma.

Comparison of biomechanical properties of light mesh endoprostheses with different structural characteristics.

Three types of light mesh endoprostheses with different jersey structure were implanted into the anterior abdominal walls of 18 rabbits. Changes in the geometrical size and mechanical properties of the prostheses detected 3 months after implantation largely depended on the jersey structure and distribution of mature connective tissue in the structure of the material.

Experimental study of the impact of the textile structure of mesh endoprostheses for the efficiency of reconstruction of the anterior abdominal wall.

Endoprostheses made from knitted fabric of 3 loop types were used for hernioplasty in rats. Biocompatibility of implanted textile constructions was evaluated after 6 months. The intensity of inflammatory reaction and types of complications in animals depended on the loop type and method of finishing of the mesh endoprosthesis tissue.

Mesh migration into the esophageal wall after mesh hiatoplasty: comparison of two alloplastic materials.

BACKGROUND: Hiatal mesh implantation in the operative treatment of gastroesophageal reflux disease has become an increasing therapy option. Besides clinical results little is known about histological changes in the esophageal wall. METHODS: Two different meshes [polypropylene (PP), Prolene; polypropylene-polyglecaprone 25 composite (PP-PG), Ultrapro] were placed on the diaphragm circular the esophagus of 20 female rabbits. After three months a swallow with iodine water-soluble contrast medium for functional analysis was performed. After the animals were sacrificed, histopathological evaluation of the foreign-body reaction, the localization of the mesh relating to the esophageal wall was analyzed. RESULTS: Sixteen rabbits survived the complete observation period of three months. After three months distinctive mesh shrinkage was observed in all animals and meshes had lost up to 50% of their original size before implantation. We found a delayed passage of the fluid into the stomach in all operated animals. There was a significant increased diameter of the outer ring of granulomas in the PP group (76.5 +/- 8.0) compared to the PP-PG group (64 +/- 8.5; p = 0.002). However, we found a mesh migration into the esophageal wall in six out of seven animals (PP) and five out of nine animals (PP-PG), respectively. CONCLUSION: Experimental data suggest that more knowledge is necessary to assess the optimal size, structure, and position of prosthetic materials for mesh hiatoplasty. The indication for mesh implantation in the hiatal region should be carried out very carefully.

Modification of collagen formation using supplemented mesh materials.

BACKGROUND: Formation of recurrent inguinal and incisional hernia shows an underlying defect in the wound healing process. Even following mesh repair an altered collagen formation and insufficient mesh integration has been found as main reason for recurrences. Therefore the development of bioactive mesh materials to achieve a local modification of the scar formation to improve patients outcome is advisable. METHODS: Thirty-six male Wistar rats were used within this study. A Mersilene (R) mesh sample was implanted after midline skin incision and subcutaneous preparation. Before implantation mesh samples were incubated for 30 minutes with either one of the following agents: doxycycline, TGF-beta 3, zinc-hydrogeneaspartate, ascorbic acid, hyaluronic acid. Incubation with a physiologic 0.9 % NaCl solution served as control. Seven and 90 days after mesh implantation 3 animals from each group (n = 6) were sacrificed for morphological observations. Collagen quantity and quality was analyzed measuring the collagen/protein as well as the collagen type I/III ratio. RESULTS: Following an implantation interval of 90 days supplementation with doxycycline (39.3 +/- 7.0 microg/mg) and hyaluronic acid (34.4 +/- 5.8 microg/mg) were found to have a significantly increased collagen/protein ratio compared to implantation of the pure Mersilene (R) mesh samples (28.3 +/- 1.9 microg/mg). Furthermore, an overall increase of the collagen type I/III ratio was found in all groups indicating scar maturation over time. However, no significant differences were found after 7 and 90 days of implantation comparing collagen type I/III ratio of supplemented mesh samples and control group. CONCLUSIONS: In summary, we found an influence of supplemented mesh materials on collagen deposition. However, the investigated bioactive agents with reported influence on wound healing were not associated with an improved quality in scar formation.