Prevention of adhesions with crystalloids during laparoscopic surgery in mice

Diagnosis and treatment of early-stage endometriosis by Transvaginal Hydro laparoscopy

Background: Transvaginal Hydro Laparoscopy (THL) is known as a minimal invasive procedure allowing endoscopic exploration of the female pelvis. Objective: To evaluate the possibilities of the THL as a tool for early diagnosis and treatment of minimal endometriosis. Materials and methods: A retrospective study of a consecutive series of 2288 patients referred for fertility problems to a tertiary centre for reproductive medicine was undertaken. Mean duration of infertility was 23.6 months (SD ±11-48), mean age of patients was 31.25 (SD± 3.8y). With normal findings at clinical and ultrasound examination patients underwent, as part of their fertility exploration, a THL. Main outcome measures: Evaluation of feasibility, identified pathology and pregnancy rate. Results: Endometriosis was diagnosed in 365 patients (16%); the localisation was higher on the left side (n=237) than on the right side (n=169). Small endometriomas, with diameters between 0.5 and 2 cm, were present in 24.3% (right side in 31, left side 48 and bilateral 10). These early lesions were characterised by the presence of active endometrial like cells and a pronounced neo-angiogenesis. Destruction of the endometriotic lesions with bipolar energy resulted in an in vivo pregnancy rate (spontaneous/IUI) of 43.8% (CPR after 8 months: spontaneous 57.7%; IUI/AID 29.7%). Conclusion: THL allowed in a minimally invasive way an accurate diagnosis of the early stages of peritoneal and ovarian endometriosis with the possibility of offering treatment with minimal damage. What is new? This is the largest series reporting the usefulness of THL for the diagnosis and treatment of peritoneal and ovarian endometriosis in patients without obviously visible preoperative pelvic pathology.

Systematic use of transvaginal hydrolaparoscopy as a minimally invasive procedure in the exploration of the infertile patient: results and reflections

Background

The aim of this study was to evaluate the added value of transvaginal hydrolaparoscopy (THL) in the investigation of the infertile patient.

Methods

A retrospective cohort study, based on records from 01/09/2006 to 30/12/2019 was undertaken in a tertiary care infertility centre. THL was performed in 2288 patients. These were patients who were referred for endoscopic exploration of the female pelvis as part of their infertility investigation. In 374 patients with clomiphene- resistant polycystic ovary syndrome (PCOS), ovarian capsule drilling was also performed. The outcome objectives of this study included the evaluation of the added diagnostic value of THL as well as the feasibility and safety of the visual inspection of the female pelvis using this technique.

Results

Of the 2288 procedures failed access to the pouch of Douglas occurred in in 23 patients (1%). The complication rate was 0.74%, due to bowel perforations (n= 13) and bleeding (n= 4) requiring laparoscopy. All bowel perforations were treated conservatively, with 6 days of antibiotics, and no further complications occurred. Findings were normal in 49.8% of patients. Endometriosis was diagnosed in 366 patients (15.9%); adhesions were present in 144 patients.

Conclusions

THL is a minimally invasive procedure, with a low complication and failure rate, providing an accurate visual exploration of the female pelvis in a one-day hospital setting. When indicated, minimally invasive surgery is possible in the early stages of endometriosis and for ovarian capsule drilling in patients with clomiphene- resistant PCOS.

Use of hypertonic glucose (10%) in the prevention of postoperative adhesions in rats

Purpose

To evaluate the efficacy of hypertonic glucose (10%), alone or in combination with the corticoid dexamethasone, to prevent peritoneal adhesion following hysterectomy in rats.

Methods

Forty-two adult rats underwent hysterectomy with peritoneal lavage: G1 – glucose (10%); G2 – glucose (10%) and dexamethasone 3 mg·kg^–1; and G3 – physiological saline (PS) 0.9%.

Results

In the macroscopic analysis after 14 days, G1 had a median score of 1, G2 of 1, and G3 of 2.5 (p < 0.0001), G3 compared to G1 and G2. There was no difference between groups after 28 days. In the microscopic analysis, the median vascular proliferation after 14 days was 2 for G1, 1 for G2, and 3 for G3 (p = 0.0037, G3 vs. G1 and G2). After 28 days, G1 showed a median vascular proliferation score of 2, G2 of 2.5, and G3 of 3 (p < 0.0001, G3 vs. G1 and G2). Regarding the inflammatory reaction after 14 days, G1 had a median score of 2, G2 of 1, and G3 of 3 (p = 0.7916). After 28 days, G1 had a median score of 0.5 (0–1.75), G2 of 1.5, and G3 of 2.5 (p < 0.0001, G3 vs. the others and G2 vs. G1). In the evaluation of fibrosis after 14 days, G1 had a median score of 1, G2 of 1, and G3 of 2.5 (p < 0.0001, G3 vs. G1and G2). After 28 days, G1 had a median fibrosis score of 1, G2: 2, and G3: 2.5 (p < 0.0001), G3 vs. the others andG2 vs. G1).

Conclusions

The use of hypertonic glucose (10%) solution seems to reduce macroscopic and microscopic pelvic adhesions.

The effect of addition of dexamethasone into normal saline irrigation solution on Prevention of Intraperitoneal Adhesion Post Laparotomy in wistar rats (Rattus norvegicus)

Introduction

Intraperitoneal adhesion is a pathological condition of adhesion between the omentum, intestine and abdominal wall. The purpose of this study was to determine the effect of adding dexamethasone into normal saline fluid to prevent intra peritoneal adhesion.

Materials and methods

This study used experimental post-test only control group design. There were four treatment groups using six white rats in each group: group I without administration of normal saline and dexamethasone, group II with administration of normal saline irrigation, group III by adding dexamethasone dose 0.2 mg/BW into 5 cc normal saline, and group IV by adding 0.5 mg/BW into 5 cc normal saline. Laparotomy was performed to all samples followed by excoriation and abrasion in cecum and terminal ileum using gauze. Intra peritoneal adhesion assessment was carried out on the 10th day post laparotomy. Macroscopic and microscopic assessments were performed to evaluate formation of collagen, fibrin and the spread of inflammatory cells of each group.

Results

From macroscopic observations, it was found that the average adhesion that occurred was 3.333; 2.333; 0.666; 0.333 by using statistical calculations with one-way ANOVA with P value of 0.000. Post-Hoc analysis showed that the administration of dexamethasone 0.5 mg/BW is proven to minimize the occurrence of adhesion between the 3 groups. Microscopic assessment of the formation of collagen, fibrin and the spread of inflammatory cells by one-way ANOVA produced P 0.000 in all three parameters, but the dose of dexamethasone administration between 0.2 mg/BW and 0.5 kg/BW did not prove significant in either group.

Conclusion

There is evidence that the addition of dexamethasone to normal saline as an irrigation liquid during laparotomy can reduce the occurrence of adhesion. However, the dose difference was not proven to be better in this study. Further studies are suggested to use more experimental animals.

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Administration of dexamethasone was proven to reduce the amount of the three parameters.

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Addition of dexamethasone to normal saline as an irrigation liquid during laparotomy can reduce the occurrence of adhesion.

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Administration of normal saline can reduce inflammatory cells in the intraperitoneal adhesion tissue.

Effects of Streptokinase and Normal Saline on the Incidence of Intra-abdominal Adhesion 1 Week and 1 Month after Laparotomy in Rats

Background:

Intra-abdominal adhesions after surgery are usually in the form of bands and can annoy the patient throughout life causing repeated surgical procedures. Therefore, any action to prevent adhesions after surgery can increase longevity and quality of life. For this aim, this study investigates the effect of streptokinase and normal saline on the 7^th day and 1 month after laparotomy.

Materials and Methods:

Experimental study was conducted on thirty healthy male Wistar rats weighing 200–250 g with age of 3 months divided into three groups of 10. Group I: No treatment, Group II: Received normal saline, and Group III: Received normal saline and streptokinase at the same time. One week and 1 month after laparotomy, the frequency of the presence or absence of adhesion bands was performed by a person who was unaware of the sample grouping. The collected information was analyzed with the SPSS software (version 16; SPSS Inc., Chicago, IL, USA).

Results:

Adhesion frequency was found to be 20% on the 7^th day (early) and 1 month after laparotomy (late) for Group 1, and it was 40% on early and late for Group II, while 0% on the early and late for Group III. Hence, in the group receiving streptokinase, no early or late adhesion was observed; therefore, it had a significant role in the prevention of intra-abdominal adhesions (P < 0.05). However, adhesions in the group receiving normal saline had no remarkable difference with the group receiving no drug (P > 0.05).

Conclusion:

According to the results of our study, we believe that streptokinase could be a good antiadhesive agent considering its effectiveness.

Role of the peritoneal cavity in the prevention of postoperative adhesions, pain, and fatigue

A surgical trauma results within minutes in exudation, platelets, and fibrin deposition. Within hours, the denuded area is covered by tissue repair cells/macrophages, starting a cascade of events. Epithelial repair starts on day 1 and is terminated by day 3. If repair is delayed by decreased fibrinolysis, local inflammation, or factors in peritoneal fluid, fibroblast growth starting on day 3 and angiogenesis starting on day 5 results in adhesion formation. For adhesion formation, quantitatively more important are factors released into the peritoneal fluid after retraction of the fragile mesothelial cells and acute inflammation of the entire peritoneal cavity. This is caused by mechanical trauma, hypoxia (e.g., CO₂ pneumoperitoneum), reactive oxygen species (ROS; e.g., open surgery), desiccation, or presence of blood, and this is more severe at higher temperatures. The inflammation at trauma sites is delayed by necrotic tissue, resorbable sutures, vascularization damage, and oxidative stress. Prevention of adhesion formation therefore consists of the prevention of acute inflammation in the peritoneal cavity by means of gentle tissue handling, the addition of more than 5% N₂O to the CO₂ pneumoperitoneum, cooling the abdomen to 30°C, prevention of desiccation, a short duration of surgery, and, at the end of surgery, meticulous hemostasis, thorough lavage, application of a barrier to injury sites, and administration of dexamethasone. With this combined therapy, nearly adhesion-free surgery can be performed today. Conditioning alone results in some 85% adhesion prevention, barriers alone in 40%-50%.

Effect of ankaferd blood stopper in experimental peritoneal adhesion model

PURPOSE

Ankaferd Blood Stopper (ABS) is an herbal extract attained from 5 different plants. It has the therapeutic potential to be used for the management of external hemorrhage and controlling gastrointestinal bleedings. To date, the safety of ABS for intraperitoneal usage is not clear. In this study, we investigated the effectiveness and safety of using intraperitoneal ABS in an experimental peritoneal adhesion model.

METHODS

Twenty-four male Wistar Albino rats were used in the study. The rats were randomly divided into 3 groups: saline, ABS, and control. On the 10th day, all rats were euthanized. The adhesions were evaluated by Nair's macroscopic adhesion classification, and pathologically evaluated with Zühlke's microscopic adhesion classification.

RESULTS

macroscopic and microscopic comparison between the ABS and saline groups did not show any differences but both the ABS and saline groups were superior when compared to the control group.

CONCLUSION

ABS was found equally effective with saline on the abdominal adhesions and to no effect on postoperative adhesion formation.

The impact of the learning curve on adhesion formation in a laparoscopic mouse model

OBJECTIVE

To evaluate the impact of surgeon training on adhesion formation in a laparoscopic mouse model. Laparoscopic surgery and bowel manipulation was demonstrated to enhance postoperative adhesion formation.

DESIGN

Prospective randomized, controlled trial.

SETTING

University laboratory research center.

ANIMAL(S)

200 BALB/c and 200 Swiss female mice.

INTERVENTION(S)

Adhesions were induced by opposing bipolar lesions and 60 minutes of pneumoperitoneum. Each surgeon operated on 80 mice (40 Swiss and 40 BALB/c), the only variable thus being his/her increasing experience. Some surgeons were already experienced gynecologists, others were starting their training.

MAIN OUTCOME MEASURE(S)

End points were the duration of surgery while performing the lesions. The adhesion formation was scored quantitatively (proportion and total) and qualitatively (extent, type, and tenacity) after 7 days.

RESULT(S)

With training, duration of surgery and adhesion formation decreased exponentially for all surgeons, whether experienced or not. Experienced surgeons had initially a shorter duration of surgery, less adhesion formation, and less de novo adhesions than inexperienced surgeons.

CONCLUSION(S)

These data suggest that laparoscopic skills improve with training, leading to a decrease in the duration of surgery and formation of adhesions. Therefore completion of a standardized learning curve should be mandatory when initiating adhesion formation studies both in laboratory or clinical setting.

Postoperative inflammation in the abdominal cavity increases adhesion formation in a laparoscopic mouse model

OBJECTIVE

To investigate acute inflammation in the peritoneal cavity in adhesion formation.

DESIGN

Prospective randomized, controlled trial.

SETTING

University laboratory research center.

ANIMAL(S)

9- to 10-week-old BALB/c female mice.

INTERVENTION(S)

In a laparoscopic mouse model, acute inflammation in the peritoneal cavity evaluated in CO(2) pneumoperitoneum enhanced adhesions, by CO(2) pneumoperitoneum plus manipulation, and in the latter group plus dexamethasone.

MAIN OUTCOME MEASURE(S)

Qualitative and quantitative adhesion scores and an acute inflammation score (neoangiogenesis, diapedesis, and leukocyte accumulation).

RESULT(S)

Adhesions at the lesion site were enhanced by the CO(2) pneumoperitoneum, further enhanced by manipulation, and decreased by the administration of dexamethasone. The acute inflammation scores (total, neoangiogenesis, diapedesis, and leukocyte accumulation) strongly correlated with the total adhesion score. Inflammation scores were similar at both the surgical lesion and the parietal peritoneum.

CONCLUSION(S)

Acute inflammation of the entire peritoneum cavity is an important mechanism involved in adhesion formation and enhances adhesion formation at the lesion site.

Intercoat gel (oxiplex): efficacy, safety, and tissue response in a laparoscopic mouse model

STUDY OBJECTIVE

To study the efficacy and safety of Intercoat gel in a laparoscopic mouse model with pneumoperitoneum-enhanced adhesion formation.

DESIGN

Randomized controlled trial. Evidence obtained from a properly designed, randomized, controlled trial (Canadian Task Force classification I).

SETTING

University laboratory research center.

SUBJECTS

Balb\c female mice 9 to 10 weeks old.

INTERVENTIONS

Two laparoscopic mouse models for adhesion formation were used. In the first model, adhesions following bipolar opposing lesions in the pelvis were enhanced by 60 minutes of carbon-dioxide pneumoperitoneum. In the second model, adhesions were further enhanced by bowel manipulation. The first experiment evaluated the efficacy of Intercoat in both models. The second experiment evaluated the efficacy of Intercoat in the first model, when applied immediately on the lesion, when applied at the end of the pneumoperitoneum, and when applied in the upper abdomen. Biopsy specimens were taken after 7 days and were evaluated after hematoxylin-eosin and CD45 staining.

MEASUREMENTS AND MAIN RESULTS

Qualitative and quantitative adhesion scoring. Morphology was evaluated by standard light microscopy. In both models, Intercoat decreased adhesion formation whether applied immediately on the lesion or at the end of the pneumoperitoneum (qualitative and quantitative scoring p <.0001 and p <.0001, respectively). Intercoat application is associated with tissue redness, vascular congestion, and cellular edema but without an inflammatory reaction. Applied in the upper abdomen, Intercoat does not increase adhesions, but decreases adhesions at higher doses (p =.0024). Intercoat in high doses had a toxic effect (p =.0058).

CONCLUSION

Intercoat is an effective antiadhesion product. It is associated with tissue edema and vasodilatation as observed after 7 days both macroscopically and by histology.

Efficacy of barriers and hypoxia-inducible factor inhibitors to prevent CO(2) pneumoperitoneum-enhanced adhesions in a laparoscopic mouse model

STUDY OBJECTIVE

To investigate the effects of hypoxia-inducible factor (HIF) inhibitors, flotation agents, barriers, and a surfactant on pneumoperitoneum-enhanced adhesions in a laparoscopic mouse model.

DESIGN

Prospective randomized trial (Canadian Task Force classification I).

SETTING

Department of Obstetrics and Gynecology, University Hospital Gasthuisberg, Catholic University of Leuven.

SUBJECTS

One hundred fourteen female BALB/c mice.

INTERVENTIONS

Adhesions were induced during laparoscopy in BALB/c female mice. Pneumoperitoneum was maintained for 60 minutes with humidified CO(2). In 3 experiments the effects of HIF inhibitors such as 17-allylamino 17-demethoxygeldanamycin, radicicol, rapamycin, and wortmanin, flotation agents such as Hyskon and carboxymethylcellulose, barriers such as Hyalobarrier gel and SprayGel, and surfactant such as phospholipids were evaluated.

MEASUREMENTS AND MAIN RESULTS

Adhesions were scored after 7 days during laparotomy. Adhesion formation decreased with the administration of wortmannin (p <.01), phospholipids (p <.01), Hyalobarrier Gel (p <.01), and SprayGel (p <.01).

CONCLUSIONS

These experiments confirm the efficacy of barriers and phospholipids to separate or lubricate damaged surfaces. They also confirm the role of mesothelial hypoxia in this model by the efficacy of the HIF inhibitor wortmannin.

Effect of reactive oxygen species scavengers, antiinflammatory drugs, and calcium-channel blockers on carbon dioxide pneumoperitoneum-enhanced adhesions in a laparoscopic mouse model

BACKGROUND

Postoperative adhesions are a clinical problem. They can cause female infertility, intestinal obstruction, chronic pelvic pain, and difficulties at the time of reoperation. A variety of approaches described to prevent adhesions have shown variable and inconsistent results. Therefore, this study aimed to evaluate most known substances in a laparoscopic mouse model to obtain quantitative and comprehensive information on adhesion prevention. Specifically, this first study aimed to investigate the effects of reactive oxygen species (ROS) scavengers, antiinflammatory agents, and a calcium-channel blocker on pneumoperitoneum-enhanced adhesions.

METHODS

Adhesions were induced during laparoscopy in BALB/c female mice by creation of a bipolar lesion. Carbon dioxide (CO2) pneumoperitoneum was maintained for 60 min using humidified CO2. Six experiments were conducted to evaluate the effects of ROS scavengers (superoxide dismutase [SOD], catalase, melatonin, and ascorbic acid), antiinflammatory agents (dexamethasone, tenoxicam, ibuprofen, parecoxib, nimesulide, anti-tumor necrosis factor [TNF]-alpha), and a calcium-channel blocker (diltiazem). Adhesions were scored after 7 days during laparotomy.

RESULTS

Adhesions were reduced by SOD (p < 0.01, proc general linear methods (GLM) of experiments 1 and 2), diltiazem (p = 0.05, Wilcoxon), and dexamethasone (p < 0.03), but not by nonsteroidal antiinflammatory drugs (NSAIDs) nor by anti-TNF-alpha. When all the experiments were grouped for analysis, adhesions also decreased with one and three doses of SOD (p < 0.01 and p < 0.01, respectively) and with one and three doses of ascorbic acid (p < 0.02 and p = 0.05, respectively).

CONCLUSIONS

These experiments confirm that SOD, diltiazem, and dexamethasone can decrease adhesion formation. The absence of effect from the other antiinflammatory drugs and anti-TNF-alpha is surprising.

Effect of desiccation and temperature during laparoscopy on adhesion formation in mice

OBJECTIVE

To investigate the effects of desiccation (without cooling) and of oversaturation of the pneumoperitoneum on adhesion formation.

DESIGN

Prospective randomized trial.

SETTING

Academic research center.

ANIMAL(S)

BALB/c and NMRI female mice.

INTERVENTION(S)

The effect of desiccation using nonhumidified CO(2) on adhesion formation was evaluated in a laparoscopic mouse model. Body temperature (BT) was maintained at 37 degrees C using a homeothermic blanket. In addition to controls without desiccation, the effect of both hypothermia and desiccation on adhesion formation was evaluated. Subsequently the effect of oversaturating the pneumoperitoneum using a high energy gas to avoid any desiccation was studied.

MAIN OUTCOME MEASURE(S)

During surgery BT, pneumoperitoneum temperature, and relative humidity were monitored. Adhesions were scored after 7 days.

RESULT(S)

Adhesions increased with increasing levels of desiccation when BT was kept at 37 degrees C. This was prevented with humidified gas. If BT decreased, adhesions were fewer. Oversaturating the pneumoperitoneum increased adhesions due to high energy gas causing an increase in both BT and pneumoperitoneum temperature.

CONCLUSION(S)

Adhesions increase with desiccation and decrease when BT is reduced. Adhesions are minimized when humidified gas is used. Since desiccation is associated with cooling, its effect is generally underestimated because of the counterbalance with cooling. The concept of combining controlled intraperitoneal cooling with a rigorous prevention of desiccation might be important for clinical adhesion prevention.

Adhesion formation and interanimal variability in a laparoscopic mouse model varies with strains

Adhesion formation after laparoscopic surgery was evaluated in mice of different strains. More adhesions were observed in Swiss, NMRI, and BALB/c mice, with less interanimal variability in BALB/c mice. These data point to genetics effects on adhesion formation, which open new insights in its pathogenesis and indicate the importance of a careful strain selection for animal studies.

Ringer’s lactate solution remains in the peritoneal cavity after laparoscopy longer than expected

OBJECTIVE

To evaluate by serial ultrasound scans how long a Ringer's lactate instillation remains in the peritoneal cavity after laparoscopy.

DESIGN

Prospective, randomized, double blind, clinical trial.

SETTING

Tertiary care, university hospital.

PATIENT(S)

Thirty-six patients undergoing diagnostic or minor operative laparoscopy.

INTERVENTION(S)

At the end of laparoscopy, the patients were tilted to an anti-Trendelenburg position and all fluid was aspirated. The patients were then randomized to receive an instillation of 300 mL of Ringer's lactate or no fluid instillation. Serial transvaginal ultrasound scans were performed at the end of surgery and at 24, 48, and 96 hours after the surgery.

MAIN OUTCOME MEASURE(S)

Through direct measurements of scalar fluid volumes instilled in the operating room and real-time ultrasound comparisons, an empiric formula was calculated to correlate actual intraperitoneal volumes to ultrasonically derived measurements of fluid pockets. With this formula, the volume of intraperitoneal fluid at 24, 48, and 96 hours after surgery was calculated.

RESULT(S)

Twenty-four hours after surgery, a mean volume of 184 mL was present in the Ringer's lactate group versus 46 mL in the control group. At 48 hours after surgery, the mean volumes were 78 mL versus 30 mL, respectively. No statistically significant differences were found after 96 hours.

CONCLUSION(S)

Peritoneal absorption of instilled crystalloids is traditionally reported to be 30 to 60 mL/hour. We report detecting statistically significant amounts of fluid at 24 and 48 hours after surgery, after infusion of 300 mL of Ringer's lactate. This suggests that fluid remains in the peritoneal cavity longer than traditionally believed.

Prevention of adhesions by sodium chromoglycate, dexamethasone, saline and aprotinin after pelvic surgery

BACKGROUND

The purpose of the present paper was to assess the efficacy of saline, sodium chromoglycate, dexamethasone and aprotinin, in single or in combined use in reducing postoperative pelvic adhesion formation in a rabbit model.

METHODS

A standard lesion was performed to induce adhesion formation. Forty-five rabbits were divided into nine study groups. Group 1 was the non-treatment group. In group 2, 3 cm(3) of the rabbits' own serum was instilled i.p. In group 3, 5 mg/kg sodium chromoglycate and 3 cm(3) of the rabbits' own serum were administered i.p. The group 4 rabbits were instilled with 5 mg/kg sodium chromoglycate, 3 cm(3) rabbits' own serum and 1 mg/kg dexamethasone i.p. The group 5 rabbits were injected with 5000 units aprotinin i.m. 2 h before operation and 5 mg/kg sodium chromoglycate, 3 cm(3) of rabbit serum, 1 mg dexamethasone and 5000 units aprotinin instilled i.p. In group 6, 3 cm(3) saline was instilled i.p. Groups 7, 8 and 9 were a repeat of groups 4, 5 and 6 with the exception of replacement of the rabbit serum by 3 cm(3) saline. Animals were evaluated for adhesions 10 days after operation.

RESULTS

Macroscopic adhesion scores of all the groups (2-9) were significantly less than scores of the control group (group 1). The macroscopic adhesion scores of group 9 and group 8 were significantly less compared to that of group 7.

CONCLUSION

Intraperitoneal instillation of saline and sodium chromoglycate decreased pelvic adhesion formation significantly in a rabbit model. Addition of aprotinin and dexamethasone to these agents gave a further advantage in decreasing pelvic adhesion formation.

Efficacy of three adhesion-preventing agents in reducing severe peritoneal trauma induced by bipolar coagulation in a laparoscopic rat model

OBJECTIVE

To compare the antiadhesion efficacy of three agents (4% icodextrin, ferric hyaluronate gel, and Ringer's lactate) in severe peritoneal trauma caused by bipolar coagulation in a laparoscopic rat model.

DESIGN

Prospective, randomized, blinded experimental study.

SETTING

International Laparoscopic Surgery Centre, Clermont-Ferrand, France.

ANIMAL(S)

Female Sprague-Dawley rats.

INTERVENTIONS

Animals were prospectively randomized to receive one of the three agents or to be controls. Coagulation of the parietal peritoneum was performed using a bipolar 40-W current followed by administration of an antiadhesion agent. Postoperative adhesion assessment was carried out on day 7 in 42 rats.

MAIN OUTCOME MEASURE(S)

Adhesions were scored according to their extent and severity.

RESULT(S)

Adhesions occurred in all rats, however, adhesion and vascular adhesion rate scores were significantly higher in controls compared with treated groups. Adhesions were more likely to be filmy and easily separable in the 4% icodextrin group compared with the Ringer's lactate solution group.

CONCLUSION(S)

Adhesion scores were decreased by the use of antiadherent agents. However, no rats were found to be free of adhesions after severe peritoneal trauma induced by 40-W bipolar coagulation of the peritoneum.

Effect of adding more than 3% oxygen to carbon dioxide pneumoperitoneum on adhesion formation in a laparoscopic mouse model

OBJECTIVE

To investigate the effect of the addition of 3% or higher oxygen concentrations to the carbon dioxide (CO2) pneumoperitoneum.

DESIGN

Prospective, randomized trial.

SETTING

Academic research center.

ANIMAL(S)

Female Naval Medical Research Institute mice (n = 100).

INTERVENTION(S)

Sixty minutes of CO2 pneumoperitoneum with 0%, 3%, 6%, 9%, or 12% oxygen; induction of adhesions by the creation of standardized peritoneal lesions during laparoscopy.

MAIN OUTCOME MEASURE(S)

Adhesions were quantitatively and qualitatively scored after 7 days during laparotomy to determine [1] the effect of 60 minutes of CO2 pneumoperitoneum with 0%, 3%, 6%, 9%, or 12% oxygen on adhesion formation, and [2] the effect of duration of CO2 pneumoperitoneum and insufflation pressure on adhesion formation with the addition of 0%, 3%, and 12% oxygen.

RESULT(S)

Compared with a CO2 pneumoperitoneum with 3% oxygen, adhesion formation is greater when either no oxygen or more than 3% oxygen is added to the CO2 pneumoperitoneum. These effects persisted at higher insufflation pressures and longer duration of pneumoperitoneum, both known to increase adhesion formation with pure CO2.

CONCLUSION(S)

This study confirms that adhesion formation is decreased with the addition of 3% oxygen to the CO2 pneumoperitoneum. The addition of higher oxygen concentrations, however, is deleterious. Adhesions always increase with time and duration of the pneumoperitoneum.

Effect of temperature upon adhesion formation in a laparoscopic mouse model

BACKGROUND

Pneumoperitoneum can be a cofactor in adhesion formation. Pneumoperitoneum with non-humidified gas causes desiccation in the peritoneal cavity which decreases temperature. The effect of desiccation upon adhesion formation is widely accepted. The specific effect of the associated cooling upon adhesion formation remains unexplored, and was addressed specifically in our laparoscopic mouse model.

METHODS

Adhesions were induced during laparoscopy and scored after 7 days during laparotomy. Pneumoperitoneum was performed using CO2 or CO2 with oxygen with or without humidification. Animals were placed at different environmental temperatures to modulate body and intraperitoneal temperature.

RESULTS

Anaesthesia, environment with a lower temperature and pneumoperitoneum all independently decrease body temperature. A decrease in body temperature decreases adhesion formation (P=0.004). Therefore, at 37 degrees C, pneumoperitoneum-enhanced adhesion formation is more important than at room temperature (P=0.04). As was observed at room temperature, adhesion formation at 37 degrees C increases with the duration (P=0.01) of pneumoperitoneum and decreases with the addition of 3% of oxygen (P=0.03).

CONCLUSIONS

Hypothermia reduces pneumoperitoneum-enhanced adhesion formation, which supports hypoxia as a driving mechanism, since hypothermia decreases the toxic effects of hypoxia and of the ischaemia-reperfusion process. These data could open up new possibilities for adhesion prevention in laparoscopic surgery.

Role of the plasminogen system in basal adhesion formation and carbon dioxide pneumoperitoneum-enhanced adhesion formation after laparoscopic surgery in transgenic mice

OBJECTIVE

To evaluate the role of plasminogen activator inhibitor-1 (PAI-1), urokinase plasminogen activator (uPA), and tissue-type plasminogen activator (tPA) in adhesion formation after laparoscopic surgery.

DESIGN

Prospective, randomized study.

SETTING

Academic research center.

ANIMAL(S)

Seventy female wild-type and transgenic knockout mice for PAI-1 (PAI-1(-/-)), uPA (uPA(-/-)) or tPA (tPA(-/-)).

INTERVENTION(S)

Standardized lesions to induce peritoneal adhesions were performed during laparoscopy. To evaluate basal adhesions and pneumoperitoneum-enhanced adhesions, the pneumoperitoneum was maintained for 10 minutes or 60 minutes, respectively. Peritoneal biopsy samples were obtained during and after 60 minutes of carbon dioxide pneumoperitoneum.

MAIN OUTCOME MEASURE(S)

Adhesions were blindly scored after 7 days. Concentrations of PAI-1 and tPA were measured by using enzyme-linked immunosorbent assay.

RESULT(S)

In PAI-1, uPA, and tPA wild-type mice, pneumoperitoneum enhanced adhesions. Compared with wild-type mice, basal adhesions were fewer in PAI-1(-/-) mice and more in uPA(-/-) and tPA(-/-) mice. Pneumoperitoneum did not enhance adhesions in these transgenic mice. PAI-1 concentration increased after 60 minutes of pneumoperitoneum whereas tPA concentration did not change.

CONCLUSION(S)

Impaired fibrinolysis increases basal adhesions. The absence of pneumoperitoneum-enhanced adhesions in PAI-1(-/-), uPA(-/-), and tPA(-/-) mice and the increase in PAI-1 expression indicate that PAI-1 up-regulation by carbon dioxide pneumoperitoneum is a mechanism of pneumoperitoneum-enhanced adhesion formation.