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.

Histoenzymological Characteristics of Smooth Muscle Cells in Myocardial Vessels: A Comparative Study under Conditions of Increased Left or Right Ventricular Afterload.

Histoenzymological methods were used to study metabolism of smooth muscle cells of intramural myocardial arteries during experimental aortic or pulmonary artery stenosis. Aortic stenosis was accompanied by changes in smooth muscles of the left ventricle manifested by deceleration of tricarboxylic acid cycle, inhibition of oxidation of free fatty acids and their metabolites, flux redistribution in the glycolytic cascade, and inhibition of shuttle systems and biosynthetic processes. Similar metabolic alterations were observed in vessels of the ventricular septum, but they were not revealed in vessels of the right ventricle (except glycolysis stimulation). Under conditions of pulmonary artery stenosis, histoenzymological alterations in vascular smooth muscle of both ventricles and ventricular septum were similar, which attested to acceleration of tricarboxylic acid cycle, stimulation of oxidation of the free fatty acids with their metabolites, acceleration of glycolysis, and activation of the shuttle systems and biosynthetic processes. Comparative analysis of histoenzymological alterations revealed substantial differences in the character of metabolic changes under conditions of increased left and right ventricular afterload, which can be caused by peculiarities in myocardial blood flow, severity of circulatory disorders, severity of hypoxia, and intensity of processes maintaining ionic homeostasis in vascular smooth muscles and transport across the histohematic barriers. The data attest to important metabolic role of glycolysis in vascular smooth muscles of the myocardium, especially under conditions of enhanced afterload of the right ventricle.

[FACTORS AFFECTING SPERMATOGENESIS PRESERVATION IN RATS WITH SEMINIFEROUS TRACT OBSTRUCTION].

The aim of the study was to examine the effect of the seminal tract obstruction of different degree and duration on the morphological and functional condition of testicular tissue. The study was conducted in 50 male Wistar rats. Three experimental models of seminiferous tract obstruction were set up: obstruction of the proximal part of the ductus deferens, obstruction of the distal part of the ductus deferens and obstruction of at the epididymis level. Morphological evaluation of testicular tissue was performed at 3 and 6 months after the obstruction. It was found that obstruction at the epididymis level caused the most severe impairment of spermatogenesis.

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.

Intraabdominal adhesion formation of polypropylene mesh. Influence of coverage of omentum and polyglactin.

BACKGROUND: Adhesions after intraabdominal surgical procedures are related to high morbidity and mortality. Biomaterials, particularly those made of polypropylene, in the intraabdominal position have to be considered as pathophysiological cofactor in a multifactorial process of adhesion formation. To investigate the adhesive potential induced by the biomaterial, an animal model was performed. In addition, the influence of coverage by omentum or a polyglactin barrier was investigated. METHODS: In, 18 Chinchilla rabbits the biomaterial was placed laparoscopically using the intraperitoneal onlay mesh technique. Using this model, a polypropylene-polyglactin mesh compound (PPMC) was used with three different implantation techniques: group 1, PPMC implantation without coverage (PPMC): group 2, PPMC implantation with additional omentum coverage (PPMC-O): and group 3, PPMC implantation with coverage of an absorbable polyglactin mesh (PPMC-V). The degree of adhesion formation was measured 90 days after implantation by computer-assisted planimetry. Morphometric examination followed the explantation analyzing the amount of foreign body response. RESULTS: We found a significant reduction of adhesion formation for the PPMC and PPMC-O groups compared to the PPMC-V group, in which dense adhesions were found. Morphometric investigations of the perifilamental granulomas of the pure (PPMC) group revealed a typical foreign body reaction with a mild to moderate fibrosis around all mesh fibers. However, tissue specimens of the PPMC-O and PPMC-V groups indicated a similar inflammatory reaction but significantly increased connective tissue formation around the polymer fibers compared to the pure PPMC group. CONCLUSION: The intraabdominal placement of a pure PPMC shows a neoperitonealization and perifilamental collagenous ingrowth with almost no adhesions. Coverage with omentum (PPMC-O) or polyglactin mesh (PPMC-V) resulted in a significant increase in inflammation and perifilamentary connective tissue formation.

Effects of intra-abdominal drainages on adhesion formation and prevention by phospholipids in a rat model. Drainages and adhesion formation.

BACKGROUND AND AIMS: The study was designed to asses the adhesiogenic capacity of silicone drainages and the protective effect of phospholipids (PL). MATERIALS AND METHODS: A total of 75 Wistar rats were randomly assigned to the different groups. In a preliminary trial (pt; n = 15), all rats underwent midline laparotomy. The control group (C(pt); n = 5) received no further treatment. In the other animals, either an 'easy flow' drainage (EF(pt); n = 5) or an 'Aachen' drainage (AC(pt); n = 5) was placed into the abdominal cavity. In the final study (fs; n = 60), rats underwent laparotomy and colonic anastomosis. The control groups (C(fs)) received no drainages. In the other groups either one of the two types of drainages (EF(fs), AC(fs)) were introduced. In 50% of the rats, 75 mg/kg of PL were administered intraperitoneally (C(fs)+PL, EF(fs)+PL, AC(fs)+PL). The other rats received no additional treatment (C(fs)ØPL, EF(fs)ØPL, AC(fs)ØPL). All animals were sacrificed 10 days after surgery. Areas of adhesions and anastomotic bursting pressures were measured (mean +/- SD). RESULTS: In the preliminary trial, analysis of variance (ANOVA) revealed no differences between the groups after application of drainages (values are given in mean +/- SD): C(pt) mean 23.3 +/- 29.4 mm(2), EF(pt) 829.7 +/- 679.3 mm(2), AC(pt) 609.9 +/- 219.4 mm(2). In the final study, 2-factorial ANOVA showed a significant effect (p < 0.001) for the use of drainages but not for the application of PL (C(fs)ØPL 140.6 +/- 124.2 mm(2), C(fs)+PL 67.7 +/- 60.4 mm(2), EF(fs)ØPL 1,217.0 +/- 458.3 mm(2), EF(fs)+PL 1,266.8 +/- 368.3 mm(2), AC(fs)ØPL 861.7 +/- 274.8 mm(2), AC(fs)+PL 544.2 +/- 193.8 mm(2)). Post hoc test for pairwise comparisons adjusted to Bonferroni showed significant differences (p < 0.001) between all of the three pairs (C(fs) 104.1 +/- 92.3 mm(2) vs. EF(fs) 1,241.9 mm(2) +/- 413.3 mm(2); C(fs) vs. AC(fs) 702.9 mm +/- 234.3 mm(2); EF(fs) vs. AC(fs)). DISCUSSION: The final study demonstrates the adhesiogenic capacity of silicone drainage tubes in combination with anastomoses. Any protective effect of PL alone or in combination with drainages could not be shown. CONCLUSIONS: Indication for the use of drainages in standard surgical procedures should be reconsidered within the scope of their potential to cause adhesions and subsequent complications.

Influence of intraperitoneal phospholipid dosage on adhesion formation and wound healing at different intervals after surgery.

BACKGROUND: Adjuvant therapy is needed to prevent adhesion formation as a major cause of postoperative morbidity and mortality. The efficacy of phospholipids (PLs) has been proven; however, information on dosage and drug safety are still outstanding. MATERIALS AND METHODS: Forty-eight Chinchilla rabbits underwent median laparotomy, abrasion of the peritoneum, jejunal anastomosis, and an electrocautery incision of the liver. The operation was completed by intraperitoneal administration of PLs in two different concentrations (30 mg/kg and 70 mg/kg body weight). In the control group, the abdomen was closed without additional treatment. Adhesion area, anastomotic bursting pressure, tensile strength of the midline incision, and healing of the liver wound were assessed on days 3, 5, 7, and 10, respectively. RESULTS: The mean areas of adhesions in the control group were slightly larger than in the PL groups after 3 days and 5 days. On day 7 and day 10, both PL groups presented with significantly smaller adhesion areas (P<0.05). In all groups, we measured equal anastomotic bursting pressures on the 3rd, 5th, and 10th postoperative days. After 7 days, the mean value of the PL 70-mg group (17.2 kPa) was significantly lower than in the other groups (control 22.1 kPa, PL 30 mg 20.7 kPa; P<0.05). The tensile strengths of the laparotomy wound measured after intervals of 5 days and 7 days were not statistically different. On day 3, it was reduced after 30 mg PL but enhanced after 70 mg PL, whereas 10 days after surgery the strength increased with the PL dosage. The inflammatory reparative response to hepatic injury, jejunal anastomosis, and midline incision was not affected by PLs as assessed by histological analysis. CONCLUSION: These results prove the efficacy of PLs in adhesion prevention in two concentrations. The findings reveal an unimpeded healing of anastomoses, laparotomy wounds, and liver incisions at different periods after surgery.

Efficacy of adhesion prevention and impact on wound healing of intraperitoneal phospholipids.

BACKGROUND: Postoperative peritoneal adhesions are a major complication of abdominal surgery. Adjuvant therapy is needed to prevent adhesion formation and subsequent sequelae. Previously published data proved the efficacy of phospholipids (PL) for this indication; however, additional information on drug safety was still outstanding. The underlying study was designed to investigate the influence of phospholipids on three different types of healing tissue. MATERIALS AND METHODS: A total of 48 Chinchilla rabbits underwent median laparotomy, standardized abrasion of the visceral and parietal peritoneum, jejunal anastomosis, and an electrocautery incision of the liver. The operation was completed by intraperitoneal administration of 10 ml/kg of either normal saline (NaCl) or phospholipids (12%). RESULTS: After 5 (NaCl 691 mm(2) vs PL 192 mm(2)) and 10 days (NaCl 625 mm(2) vs PL 88 mm(2)) the control group presented with significantly larger adhesion areas (P < 0.05). The bursting pressure of the anastomosis on the 5th (NaCl 16.1 kPa vs PL 18.2 kPa) and 10th (NaCl 19.7 kPa vs PL 18.6 kPa) postoperative days showed no statistically significant difference. The tensile strength of the laparotomy wound measured after intervals of 5 (NaCl 8.5 N cm(-1) vs PL 6.8 N cm(-1)) and 10 days (NaCl 23.0 N cm(-1) vs PL 20.2 N cm(-1)) was not statistically different either. The collagen protein ratio of anastomoses, laparotomy wounds, and liver incisions as well as the inflammatory-reparative response of the different tissues was not affected by PL. CONCLUSIONS: These results confirm the efficacy of phospholipids in adhesion prevention. The findings of uncompromised healing of anastomoses, laparotomy wounds, and liver incisions demonstrate the safety of this agent. Further data may qualify phospholipids for a clinical trial.

Colon interposition for esophageal replacement: isoperistaltic or antiperistaltic? Experimental results.

BACKGROUND: Isoperistaltic colon is preferred to antiperistaltic colon for esophageal replacement, but experimental data do not exist to support this practice. METHODS: In 7 dogs a 20 cm long colon loop was interposed between the skin and the small bowel, isoperistaltically in 3 dogs and antiperistaltically in 4 dogs. Three months later five strain-gauges were implanted and evacuation was investigated by motility testing, barium studies, and scintigraphy. RESULTS: Motility recording showed normal colon motility in the excluded loops. Quiescent states (duration 40.2 +/- 13.6 minutes) were followed by contractile states (duration 7.5 +/- 2.4 minutes, frequency 3.3 +/- 0.6 per minute). The main peristaltic direction of isoperistaltic loops was isoperistaltic, and the main peristaltic direction of antiperistaltic loops was antiperistaltic. Evacuation took place exclusively during the contractile status. Half time emptying was more rapid in isoperistaltic loops (35 +/- 11 vs 69 +/- 16 minutes). The content of antiperistaltic loops was held back by antiperistaltic activity. Application of oatmeal porridge into the loops shortened the quiescent status from 40.2 to 13.2 +/- 4.8 minutes. CONCLUSIONS: The colon graft for esophageal replacement is an active system. Food is stored during the quiescent states and evacuated during the contractile states. The original peristaltic direction is preserved so that retroperistalsis in antiperistaltic loops may lead to patient discomfort and pulmonary complications.

Effect of artificial valves on intestinal adaptation in the short-bowel syndrome: an integrated study of morphological and functional changes in rats.

Two-third-resections of the proximal or distal small bowel with and without artificial valves were performed in rats. Intestinal adaptation led to a significant increase in bowel diameter, villus height and villus diameter and consequently in absorptive mucosal surface area per unit of serosal area. Additional artificial valve construction did not affect the calculated mucosal surface area after proximal resection, while it significantly decreased the absorptive area by the occurrence of large, plump villi after distal resection. There was no change in small-intestinal absorption of water, glucose and electrolytes per unit mucosa with valve construction. DNA cytometry showed that artificial valves led to mucosal hyperplasia without hypertrophy. These morphological changes coincided with a significant increase in basal and stimulated gastrin release. The body weight was unchanged or even worse in the valve groups than after resection alone, despite a significantly prolonged transit time. Therefore, in our study, artificial valves did not result in functional improvements after small intestinal resections.

Electrophysiological and mechanical activity of the upper gastrointestinal tract after duodenoplasty or segmental resection of benign gastric outlet stenosis.

In an animal experimental study we examined the postoperative recovery of the motility of the upper gastrointestinal tract after operative treatment of a benign gastric outlet obstruction. At 45 Days after induction, a duodenal stenosis was resected in six dogs, and resolved by Finney's duodenoplasty in another six dogs. Fourteen days after segmental resection, the gastric emptying was faster [half evacuation time (T1/2) for semisolid food = 44.4 +/- 16.8 min] than following duodenoplasty [T1/2 = 56.8 +/- 25.3). Here motor migrating complexes (MMCs) started in the antrum and could be traced down to the jejunum. After segmental resection we recognized MMC only distal to the anastomosis. The duration of the whole MMC cycle (69.0 +/- 18.6 min) as well as of the single phases was significantly shorter in the resection group than after duodenoplasty (108.0 +/- 15.1 min). At 28 days after operation the differences in the electromyographic findings were smaller (82.0 +/- 15.1 min vs. 111.4 +/- 11.2 min), but still significant. Obviously humoral transmitters and the extrinsic neural system lead to good propagation of the MMC across the anastomosis, even before the intramural pathways are reestablished. Concerning the fast recovery of the motility of the upper gastrointestinal tract, duodenoplasty is superior to segmental duodenal resection.

[Changes in reactivity of the contractile system of the small intestine caused by disturbed parasympathetic innervation]. / Izmenenie reaktivnosti sokratitel'nogo apparata tonkoi kishki v usloviiakh narushennoi parasimpaticheskoi innervatsii.

We studied the role of parasympathetic division of vegetative nervous system in regulation of the intestine activity in rats subjected to bilateral subdiaphragmal vagotomy, the response of the neuromuscular apparatus of the small intestine to stimulation by aceclydine taken as an example. Intravenous injection of aceclydine (0.5 mg/kg) into intact animals is accompanied by characteristics changes in the electrical and contractile activities of the intestine, which reflect its enhanced motor activity. Vagotomy leads to changes of response of the intestine to pharmacological stimulation, most expressed within 3, 7, and 30 days. It was proposed that distortion of reactive properties of the intestine contractile system under these conditions is related to functional changes in rhythm-setting neurons of intramural ganglia and M-cholinoreceptors of neuromuscular synapses.

[Artificial pressure increase in subcutaneous abscess with evidence of general systemic reaction]. / Artifizielle Drucksteigerung im subkutanen Abszess mit Nachweis einer systemischen Allgemeinreaktion.

Abscess is customarily thought of as a collection of a large number of microorganisms, inflammatory cells and necrotic debris separated from the surrounding tissue by a fibrous capsule. Modern work focussed attention on more physico-chemical parameters in abscess pathogenesis. Recent experiences from animal models underline the impact of abscess pressure and bio-physicochemical parameters in the "abscess compartment" for systemic spreading. Artificial raising of abscess-pressure in pigs up to 80 mmHg was followed by increase of temperature and heartbeat rate and decrease of median arterial pressure. Elevated levels of TNF alpha, IL-1 and positive blood cultures support the theory of abscess pressure as a most important variable in abscess formation. We conclude that abscess pressure may play a pivotal role in systemic spreading of the primarily localized process.

[Laparoscopy versus laparotomy. An animal experiment study comparing adhesion formation in the dog]. / Laparoskopie versus Laparotomie. Eine tierexperimentelle Studie zum Vergleich der Adhäsionsbildung im Hund.

We performed laparoscopy (n = 7) or laparotomy (n = 7) for exploration of the small intestine, cecal resection with Endo-GIA or TA-30, deserosation of 2 cm2 of the abdominal wall and resection of the omentum majus in dogs. After 8 days all dogs were re-examined and the adhesions were quantified by computer-aided measurement. Laparoscopic operations were followed by significantly (P < 0.001) fewer adhesions. After conventional operations extensive adhesions to the abdominal incision and interenteric adhesions were found, together with frequent conglomerates of adhesions, intestinal kinkings or adhesive bands. Identical manipulations, such as cecal resection or deserosation of the lateral abdominal wall, led to the same frequency and severity of adhesions in both groups. Based on our results, the risk of adhesion-related complications may be reduced by the laparoscopic approach.

[The role of the parasympathetic nervous system in regulating the kinetics of the regional blood circulation in the digestive system organs]. / Rol' parasimpaticheskoi nervnoi sistemy v reguliatsii kinetiki regionarnogo krovoobrashcheniia v organakh pishchevaritel'noi sistemy.

Cranio-bulbar part of the parasympathetic nervous system proved to be important for regulation of the blood flow distribution between the organs of the gastroduodenal complex (liver, stomach, and small intestine), rate of the local blood flow and its kinetics. Investigation of the blood supply of the above mentioned organs various periods (1-60 days) after bilateral subdiaphragmatic truncal vagotomy has demonstrated the most pronounced transformations in macro- and micro-hemodynamics in the 14-30 days period. Time pattern of these changes has one maximum in liver and stomach (14-30 days) and two maxima (7 and 30 days) in small intestine.

Laparoscopic cholecystectomy: a minor abdominal trauma?

Clinical observations following laparoscopic surgery indicate a shorter period of postoperative ileus than after conventional surgery. The aim of our study was to verify disorders of postoperative motility of the small intestine by means of implanted electrodes after laparoscopic and conventional cholecystectomy (CHE) in an animal model. Four weeks after implantation of three electrodes on the jejunum, CHE was performed laparoscopically in 5 dogs and in an additional 5 dogs by laparotomy. Independent of the type of operation, normal motility (especially the migrating motility complex) was abolished during the early postoperative period. Electrical activity was characterized by the basic electrical rhythm. Time to the occurrence of the first postoperative activity front, indicating restoration of motility, varied significantly depending on the type of operation: It was 5.5 +/- 1.0 hours after laparoscopic CHE and 46 +/- 5 hours after conventional CHE. These results support the hypothesis that small peritoneal incisions and less manipulation of the intestine during laparoscopic surgery result in reduced abdominal trauma.

[Postoperative electromyographic monitoring of small intestine function in patients with peritonitis and acute intestinal obstruction]. / Electromiograficheskii kontrol za funktsionalnym sostoianiem tonkoi kishki u bolnykh s peritonitom i ostroi neprokhodimostíu kishechnika v posleoperatsionnom periode.

In 49 patients with general peritonitis and acute ileus, the authors used the method of direct electromyography. On the basis of analysis of the results, the functional state of the intestine, dynamics of its motor activity, effectiveness of the treatment performed were assessed and outcome of the disease was predicted.

[The diagnosis of motor disorders of the small intestine in peritonitis in children and the rationale for pathogenetic methods of correction]. / Diagnostika dvigatel'nykh narushenii tonkoi kishki pri peritonite u detei i obosnovanie patogeneticheskikh metodov korrektsii.

The work deals with the results of experimental (200 animals) and clinical (20 patients) study into the role of the efferent link of the autonomic nervous system in regulating motor activity of the small intestine and the possibility of using direct electroenteromyography in the diagnosis of the stages of paresis and the degree of motor disorders in peritonitis. The pathogenetic methods of treatment of intestinal paresis are substantiated. Medicamentous stimulation of the cholinergic nervous system in peritonitis is effective only when intactness of the intramural ganglia is maintained, in which case the electroenteromyographic test with neostigmine methylsulfate or cerucal may be conducted. The pathogenetic method of treatment in all other cases is medicamentous blockade of the adrenergic nervous system.