The effects of duration of CO2 insufflation and irrigation on peritoneal microcirculation assessed by free radical scavengers and total glutathion levels during operative laparoscopy

Underneath Images and Robots, Looking Deeper into the Pneumoperitoneum: A Narrative Review

Laparoscopy offers numerous advantages over open procedures, minimizing trauma, reducing pain, accelerating recovery, and shortening hospital stays. Despite other technical advancements, pneumoperitoneum insufflation has received little attention, barely evolving since its inception. We explore the impact of pneumoperitoneum on patient outcomes and advocate for a minimally invasive approach that prioritizes peritoneal homeostasis. The nonlinear relationship between intra-abdominal pressure (IAP) and intra-abdominal volume (IAV) is discussed, emphasizing IAP titration to balance physiological effects and surgical workspace. Maintaining IAP below 10 mmHg is generally recommended, but factors such as patient positioning and surgical complexity must be considered. The depth of neuromuscular blockade (NMB) is explored as another variable affecting laparoscopic conditions. While deep NMB appears favorable for surgical stillness, achieving a balance between IAP and NMB depth is crucial. Temperature and humidity management during pneumoperitoneum are crucial for patient safety and optical field quality. Despite the debate over the significance of temperature drop, humidification and the warming of insufflated gas offer benefits in peritoneal homeostasis and visual clarity. In conclusion, there is potential for a paradigm shift in pneumoperitoneum management, with dynamic IAP adjustments and careful control of insufflated gas temperature and humidity to preserve peritoneal homeostasis and improve patient outcomes in minimally invasive surgery.

Clinical Outcomes after the Use of Antiadhesive Agents in Laparoscopic Reproductive Surgery

INTRODUCTION

Intra-abdominal adhesions are abnormal fibrous attachments between tissues and organs that can be congenital or acquired. Adhesion formation is a critical postoperative complication that may lead to bowel obstruction, chronic abdominal pain, and infertility. Physical barrier agents separate opposing peritoneal surfaces in the critical 5-day period of remesotheliazation. These agents are subdivided into solid or liquid/gel. Liquid agents seem easier to use in laparoscopic procedures than solid agents.

METHODS

The search for suitable articles published in English was carried out using the following databases: MEDLINE, Embase, Global Health, the Cochrane Library (Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, Cochrane Methodology Register), Health Technology Assessment Database, Web of Science, and search register (ClinicalTrial.gov). Only studies reporting data about the impact of the use of an antiadhesive agent on adhesion formation after a primary gynecologic laparoscopic surgery were considered eligible.

RESULTS

Twenty-two papers that met the inclusion criteria were included in this systematic review.

CONCLUSIONS

Surgeons should consider applying antiadhesive agents after gynecologic surgery to help reduce adhesion formation and its adverse effects. However, further studies are still needed to confirm their impact on reproductive outcome and to implement clear guidelines on their per-operative application.

Comparison of Deep and Moderate Neuromuscular Blockade on Intestinal Mucosal Barrier in Laparoscopic Gastrectomy: A Prospective, Randomized, Double-Blind Clinical Trial

Deep neuromuscular blockade (NMB) improves the surgical conditions and is benefit for the postoperative recovery after laparoscopic surgery. However, the mechanisms of deep NMB in promoting the recovery of intestinal function have not been completely investigated. The objective of our study was to determine the impact of the deep NMB and moderate NMB strategy on the intestinal barrier function after laparoscopic gastrectomy. We collected patients undergoing elective laparoscopic gastrectomy. Patients were randomized to deep NMB (post-tetanic count 1–2) vs. moderate NMB (train-of-four count 1–2) during the surgery. Primary outcomes were time to flatus, serum diamine oxidase (DAO) and D-lactate, and gut microbiota. Other outcomes were surgical condition scores, postoperative visual analog pain scores, and length of hospital stay. Ninety patients in deep NMB group and sixty patients in moderate NMB group completed the study. Main results showed that the time to flatus was decreased in deep NMB group (74 ± 32 h) than that in moderate NMB group (93 ± 52 h, P = 0.006). The level of serum D-lactate was statistically increased in the moderate NMB group than that in the deep NMB group (1,209 ± 224 vs. 1,164 ± 185 ng/ml, p < 0.001). But no significant differences could be detected in the level of DAO between the groups. Additionally, the 16s rRNA analysis indicated that gut microbiota were similar in Alpha diversity but distinct in Beta diversity. Furthermore, the beneficial bacteria, such as genus Lactobacillus and Bifidobacterium, were more abundant in the deep NMB group, while the potentially harmful bacteria were more abundant in the moderate NMB group. Our findings suggested that the intestinal mucosal barrier and gut microbiota were better preserved in deep NMB, which greatly improved the postoperative recovery of intestinal function after laparoscopic gastrectomy.

The "Dark Side" of Pneumoperitoneum and Laparoscopy

Laparoscopic surgery has been one of the most common procedures for abdominal surgery at pediatric age during the last few decades as it has several advantages compared to laparotomy, such as shorter hospital stays, less pain, and better cosmetic results. However, it is associated with both local and systemic modifications. Recent evidence demonstrated that carbon dioxide pneumoperitoneum might be modulated in terms of pressure, duration, temperature, and humidity to mitigate and modulate these changes. The aim of this study is to review the current knowledge about animal and human models investigating pneumoperitoneum-related biological and histological impairment. In particular, pneumoperitoneum is associated with local and systemic inflammation, acidosis, oxidative stress, mesothelium lining abnormalities, and adhesion development. Animal studies reported that an increase in pressure and time and a decrease in humidity and temperature might enhance the rate of comorbidities. However, to date, few studies were conducted on humans; therefore, this research field should be further investigated to confirm in experimental models and humans how to improve laparoscopic procedures in the spirit of minimally invasive surgeries.

Predictive value of the respiratory exchange ratio for the occurrence of postoperative complications in laparoscopic surgery: a prospective and observational study

Indirect measurement of the respiratory exchange ratio (RER) has been shown to predict the occurrence of postoperative complications after major open non-cardiac surgery. Our main objective was to demonstrate the ability of the RER, indirectly measured by the anaesthesia respirator, to predict the occurrence of postoperative complications following laparoscopic surgery. We performed an observational, prospective and monocentric study. Haemodynamic and respiratory parameters were collected at several timepoints to calculate the RER by a non-volumetric method: RER = (FetCO₂-FiCO₂)/(FiO₂-FetO₂). Fifty patients were prospectively included. Nine patients (18%) had at least one postoperative complication. The mean RER was significantly higher for the subgroup of patients with complications than the subgroup without (1.04 ± 0.27 vs 0.88 ± 0.13, p < 0.05). The RER could predict the occurrence of post-operative complications with an area under the ROC curve of 0.73 (95% CI 0.59-0.85, p = 0.021). The best cut off was 0.98, with a sensitivity of 56% and a specificity of 88%. One hour after insufflation, the FiO₂-FetO₂ difference was significantly lower and the RER was significantly higher in the complications subgroup than in the subgroup without complications (4.4/- 1.6% vs 5.8/- 1.2%, p = 0.001 and 0.95 [0.85-1.04] vs 0.83 [0.75-0.92], p = 0.04, respectively). The RER measured during laparoscopic surgery can predict the occurrence of postoperative complications.Trial registration The objectives and procedures of the study was registered at Clinicaltrials.gov (NCT03751579); date: November 23, 2018.

Laparoscopic surgery for T4 colon cancer: a risk factor for peritoneal recurrences?

BACKGROUND

Although some preclinical studies have inferred that laparoscopic surgery for advanced cancer may increase the risk of peritoneal metastasis, this potential hazard has not been fully evaluated in the clinical setting. This study aimed to clarify whether laparoscopic surgery is associated with an increased risk of postoperative peritoneal recurrence after resection of T4 colon cancer.

METHODS

This study included 272 patients who underwent curative resection for pathological T4a colon cancer without distant metastases at the University of Tokyo Hospital between 1997 and 2017. Multivariable Fine-Gray analysis was performed to evaluate whether the use of laparoscopy was an independent risk factor for postoperative peritoneal recurrence. Thereafter, oncological outcomes (overall and relapse-free survival, and organ-specific recurrence) were compared between laparoscopic colectomy and open colectomy using propensity score matching.

RESULTS

Multivariable analysis found that laparoscopic surgery was a significant risk factor for postoperative peritoneal recurrence (hazard ratio: 1.89; 95% confidence interval: 1.01-3.65; P = .046). Comparison after propensity score matching revealed that the incidence of peritoneal recurrence was significantly higher after laparoscopic colectomy than after open colectomy (5-year cumulative incidence: 28.1% vs 12.1%; P = .003).

CONCLUSION

This study suggested that laparoscopic surgery may be related to an increased risk of peritoneal recurrence in patients with pathological T4a colon cancer. Clinicians should be fully aware of this potential risk and seek an optimal treatment plan for the prevention and early detection of peritoneal metastasis.

Effects of Fullerenols on Mouse Brain Microvascular Endothelial Cells

Fullerenols, water-soluble C60-fullerene derivatives, have been shown to exert neuroprotective effects in vitro and in vivo, most likely due to their capability to scavenge free radicals. However, little is known about the effects of fullerenols on the blood–brain barrier (BBB), especially on cerebral endothelial cells under inflammatory conditions. Here, we investigated whether the treatment of primary mouse brain microvascular endothelial cells with fullerenols impacts basal and inflammatory blood–brain barrier (BBB) properties in vitro. While fullerenols (1, 10, and 100 µg/mL) did not change transendothelial electrical resistance under basal and inflammatory conditions, 100 µg/mL of fullerenol significantly reduced erk1/2 activation and resulted in an activation of NFκB in an inflammatory milieu. Our findings suggest that fullerenols might counteract oxidative stress via the erk1/2 and NFκB pathways, and thus are able to protect microvascular endothelial cells under inflammatory conditions.

Humidification during laparoscopic surgery: overview of the clinical benefits of using humidified gas during laparoscopic surgery

PURPOSE

The peritoneum is the serous membrane that covers the abdominal cavity and most of the intra-abdominal organs. It is a very delicate layer highly susceptible to damage and it is not designed to cope with variable conditions such as the dry and cold carbon dioxide (CO2) during laparoscopic surgery. The aim of this review was to evaluate the effects caused by insufflating dry and cold gas into the abdominal cavity after laparoscopic surgery.

METHODS

A literature search using the Pubmed was carried out. Articles identified focused on the key issues of laparoscopy, peritoneum, morphology, pneumoperitoneum, humidity, body temperature, pain, recovery time, post-operative adhesions and lens fogging.

RESULTS

Insufflating dry and cold CO2 into the abdomen causes peritoneal damage, post-operative pain, hypothermia and post-operative adhesions. Using humidified and warm gas prevents pain after surgery. With regard to hypothermia due to desiccation, it can be fully prevented using humidified and warm gas. Results relating to the patient recovery are still controversial.

CONCLUSIONS

The use of humidified and warm insufflation gas offers a significant clinical benefit to the patient, creating a more physiologic peritoneal environment and reducing the post-operative pain and hypothermia. In animal models, although humidified and warm gas reduces post-operative adhesions, humidified gas at 32 °C reduced them even more. It is clear that humidified gas should be used during laparoscopic surgery; however, a question remains unanswered: to achieve even greater clinical benefit to the patient, at what temperature should the humidified gas be when insufflated into the abdomen? More clinical trials should be performed to resolve this query.

What is the evidence for the use of low-pressure pneumoperitoneum? A systematic review

Background

Laparoscopic surgery has several advantages when compared to open surgery, including faster postoperative recovery and lower pain scores. However, for laparoscopy, a pneumoperitoneum is required to create workspace between the abdominal wall and intraabdominal organs. Increased intraabdominal pressure may also have negative implications on cardiovascular, pulmonary, and intraabdominal organ functionings. To overcome these negative consequences, several trials have been performed comparing low- versus standard-pressure pneumoperitoneum.

Methods

A systematic review of all randomized controlled clinical trials and observational studies comparing low- versus standard-pressure pneumoperitoneum.

Results and conclusions

Quality assessment showed that the overall quality of evidence was moderate to low. Postoperative pain scores were reduced by the use of low-pressure pneumoperitoneum. With appropriate perioperative measures, the use of low-pressure pneumoperitoneum does not seem to have clinical advantages as compared to standard pressure on cardiac and pulmonary function. Although there are indications that low-pressure pneumoperitoneum is associated with less liver and kidney injury when compared to standard-pressure pneumoperitoneum, this does not seem to have clinical implications for healthy individuals. The influence of low-pressure pneumoperitoneum on adhesion formation, anastomosis healing, tumor metastasis, intraocular and intracerebral pressure, and thromboembolic complications remains uncertain, as no human clinical trials have been performed. The influence of pressure on surgical conditions and safety has not been established to date. In conclusion, the most important benefit of low-pressure pneumoperitoneum is lower postoperative pain scores, supported by a moderate quality of evidence. However, the quality of surgical conditions and safety of the use of low-pressure pneumoperitoneum need to be established, as are the values and preferences of physicians and patients regarding the potential benefits and risks. Therefore, the recommendation to use low-pressure pneumoperitoneum during laparoscopy is weak, and more studies are required.

Effects of carbon dioxide pneumoperitoneum on postoperative adhesion formation and oxidative stress in a rat cecal abrasion model

INTRODUCTION

It is claimed that CO2 pneumoperitoneum (CP) is less adhesiogenic than laparotomy. Our aim in this study was to investigate the local oxidative stress responses and related adhesion formation resulting from exposure to CP.

METHODS

Forty-five rats were randomised into six groups. Group 1 underwent laparotomy only; in group 2, 6 mmHg CP was performed for 60 min; in group 3, the same procedure was carried out using 12 mmHg CP; in group 4, laparotomy and cecal-peritoneal abrasion were performed; in group 5, 6 mmHg CP was performed for 60 min, followed by laparotomy and cecal-peritoneal abrasion; in group 6, the same procedure was carried out using 12 mmHg CP. Groups 1, 2 and 3 were sacrificed immediately and used only for biochemical examination. The other groups were sacrificed on the 14th postoperative day.

RESULTS

The total adhesion scores, thickness, quantity, extent and type of adhesions decreased steadily in groups 4, 5 and 6 (p < 0.05). The median values for neutrophil and monocyte infiltration, and for capillary and fibroblast proliferation decreased steadily in groups 4, 5 and 6 (p < 0.05). CAT, SOD and GSHPx levels decreased significantly in line with increasing pressure in groups 1, 2 and 3. SOD and GSHPx levels were similar in groups 4, 5 and 6, while CAT levels decreased with increasing pressure in groups 4, 5 and 6.

CONCLUSION

It was found that CP is associated with less adhesion formation than laparotomy in the presence of similar antioxidant levels. The reduced adhesion formation is probably caused by a decreased inflammatory response.

Predisposing factors to post-operative adhesion development

BACKGROUND

Adhesion development is the most common sequelae of intra-abdominal and pelvic surgery and represents a significant, yet poorly understood, cause of morbidity among post-operative patients. It remains unclear, for example, exactly why adhesions form more frequently in certain tissues and/or patients, or at specific locations within them, as opposed to others. This review contributes to the growing knowledge pool by elucidating factors that potentially predispose to the development of adhesions. Given the strong correlation between a hypofibrinolytic state and adhesion formation, this review article will examine not only those factors that have been shown to directly predispose to adhesion development, but also those that are likely do so indirectly by means of altering the coagulation/fibrinolytic profile.

METHODS

A literature search was performed using the PubMed database for all relevant English language articles up to February 2014. All of the identified articles were reviewed with particular attention to predisposing factors to post-operative adhesion development. In addition, the reference lists of each article were reviewed to identify additional relevant articles.

RESULTS

Various factors have been shown to directly increase the risk of post-operative adhesion development; namely, certain genetic polymorphisms in the interleukin-1 receptor antagonist, increased estrogen exposure, and endometriosis. In addition, numerous factors are known to increase the risk of fibrosis, therefore likely increasing the risk of adhesion development indirectly. These factors include genetic polymorphisms in plasminogen activator inhibitor-1 and thrombin-activatable fibrinolysis inhibitor, diabetes mellitus, metabolic syndrome, hyperglycemia, obesity, depression, binge alcohol consumption, anti-Parkinsonian medications, oral hormone therapy, pregnancy, and cancer.

CONCLUSIONS

The literature reviewed in this paper will help to direct future research aimed at understanding the mechanisms that underlie the association of certain factors with adhesion development. This information will be crucial in the creation of adequate preventative and treatment strategies.

Selected oxidative stress markers in gynecological laparoscopy

INTRODUCTION

The surgical stress response after laparoscopy is smaller when compared with open surgery, and it is expected that after minimally invasive surgery the possible development of oxidative stress will be less severe.

AIM

To evaluate markers of pro-oxidant activity - levels of lipid peroxides and malondialdehyde - and activity of the antioxidant enzymes superoxide dismutase and glutathione peroxidase in the perioperative period in patients undergoing gynecological laparoscopy and to determine whether the duration of laparoscopy can affect these changes.

MATERIAL AND METHODS

The study included 64 patients, divided into two groups: group 1 with duration of laparoscopy up to 20 min, and group 2 with duration of the operation over 40 min. Blood samples were collected before anesthesia, 5 min after release of pneumoperitoneum, and 10 h after surgery.

RESULTS

A statistically significant increase in the levels of lipid peroxides and malondialdehyde in samples collected after surgery was found in comparison with values obtained before surgery. Also statistically significant differences existed between groups of patients with different duration of surgery. Superoxide dismutase and glutathione peroxidase activity values were significantly decreased. They were also significantly different between the two groups with different duration of surgery.

CONCLUSIONS

In our study, levels of the markers of pro-oxidant activity increased and levels of the markers of antioxidant enzymes decreased, suggesting development of oxidative stress. The duration of laparoscopic procedures affects the severity of the presented changes.

Comparison of hysterosalpingography and transvaginal hydrolaparoscopy in patients with tubal factor infertility: a prospective cohort study

Aim

To evaluate the usefulness, diagnostic accuracy, and cost-effectiveness of transvaginal hydrolaparoscopy (THL) in infertile women with abnormal hysterosalpingogram (HSG) results without obvious pelvic pathology.

Material and methods

Thirty infertile women (age: 20–40 years) who had tubal pathology in HSG were enrolled in the study. All patients underwent THL instead of standard laparoscopy. A cost analysis was performed comparing HSG and THL methods.

Results

In comparison of the HSG of cases by considering the chromopertubation results by THL, the sensitivity and specificity of HSG were 85.1% and 56%, respectively. The reasons for preferring standard laparoscopy rather than THL were: failure in accessing of Douglas (n = 3), insufficient monitoring of pelvis (n = 1), hydrosalpinx (n = 1), and intense peritubal adhesion (n = 1), which were 10%, 3%, 3%, and 3%, respectively. The complication rate was 3.8%. Cost analysis of the procedures showed that the total cost of the THL group was 34.8% lower than the HSG group.

Conclusions

In the elective patients group, THL is more feasible than HSG. Transvaginal hydrolaparoscopy is effective, simple and safe, avoiding the cost, possible complications, time and postoperative patient discomfort compared to conventional laparoscopy.

Impact of pressure and gas type on adhesion formation and biomaterial integration in laparoscopy

BACKGROUND

Laparoscopic mesh repair of inguinal and incisional hernias has been widely adopted. Nevertheless, knowledge about the impact of pneumoperitoneum on mesh integration is rare. The present study investigates pressure and gas-dependent effects of pneumoperitoneum on adhesion formation and biomaterial integration in a standardized animal model.

METHODS

Laparoscopic intraperitoneal onlay mesh implantation (IPOM) was performed in 32 female chinchilla rabbits using CO(2) or helium for pneumoperitoneum. Intra-abdominal pressures were 3 or 6 mmHg. Animals were killed after 21 days, and the abdominal wall was explanted for subsequent histopathological examinations. Adhesions were assessed qualitatively with a scoring system, and the adhesion surface was analyzed semiquantitatively by planimetry. Infiltration of macrophages (CD68), expression of matrix metalloproteinase 13 (MMP-13), and cell proliferation (Ki67) were analyzed at the mesh to host interface by immunohistochemistry. The collagen type I/III ratio was analyzed by cross-polarization microscopy to determine the quality of mesh integration.

RESULTS

After 21 days, perifilamental infiltration with macrophages (CD68) and percentage of proliferating cells (Ki67) were highest after 6 mmHg of CO(2) pneumoperitoneum. The extent of adhesions, as well as the expression of MMP-13 and the collagen type I/III ratio, were similar between groups.

CONCLUSIONS

Our experiments showed no pressure or gas-dependent alterations of adhesion formation and only minor effects on biomaterial integration. Altogether, there is no evidence for a clinically negative effect of CO(2) pneumoperitoneum.

Peritoneal adhesions in human and veterinary medicine: from pathogenesis to therapy. A review

Any peritoneal inflammatory process consequent to infections or surgical injuries may induce abdominal adhesion formation. Peritoneal adhesions are connective laciniae that develop among abdomino-pelvic organs that limit physiologic visceral motion. Consequently, fertility may be impaired, and intestinal obstruction and pelvic pain may develop, mainly in subjects that had undergone gynaecological surgery. This review illustrates the pathogenic steps of adhesiogenesis and the therapeutic scenario that evolved over the years to tackle the threat of peritoneal adhesions, both in domestic animals and in women.

Peritoneal damage: the inflammatory response and clinical implications of the neuro-immuno-humoral axis

BACKGROUND

The peritoneum is a bilayer serous membrane that lines the abdominal cavity. We present a review of peritoneal structure and physiology, with a focus on the peritoneal inflammatory response to surgical injury and its clinical implications.

METHODS

We conducted a nonsystematic clinical review. A search of the Ovid MEDLINE database from 1950 through January 2009 was performed using the following search terms: peritoneum, adhesions, cytokine, inflammation, and surgery.

RESULTS

The peritoneum is a metabolically active organ, responding to insult through a complex array of immunologic and inflammatory cascades. This response increases with the duration and extent of injury and is central to the concept of surgical stress, manifesting via a combination of systemic effects, and local neural pathways via the neuro-immuno-humoral axis. There may be a decreased systemic inflammatory response after minimally invasive surgery; however, it is unclear whether this is due to a reduced local peritoneal reaction.

CONCLUSIONS

Interventions that dampen the peritoneal response and/or block the neuro-immuno-humoral pathway should be further investigated as possible avenues of enhancing recovery after surgery, and reducing postoperative complications.

Effects of adding small amounts of oxygen to a carbon dioxide-pneumoperitoneum of increasing pressure in rabbit ventilation models

OBJECTIVE

To evaluate the metabolic consequences of the addition of oxygen to the CO(2)-pneumoperitoneum.

DESIGN

Prospective randomized study in rabbits. After 30 minutes of ventilation pneumoperitoneum was maintained for 90 minutes with pure CO(2) or CO(2) with 2% or 6% of oxygen. The intraperitoneal pressure was increased from 10 to 15 and 20 mm Hg every 30 minutes. Ventilation rate was either fixed or a progressive hyperventilation. End points were changes in arterial blood gases (Pco(2), Po(2)), pH, acid-base balance (actual base excess [ABE], standard bicarbonate [SBC], standard base excess [SBE], hydrogen carbonate [HCO(3)(-)], concentration of total carbon dioxide [Tco(2)]); oxygen and oximetry (oxyhemoglobin [O(2)Hb], oxygen saturation [So(2)], reduced hemoglobin [RHb], total oxygen concentration [To(2)], and oxygen tension at half saturation assessing hemoglobin oxygen affinity [p50]); and lactate concentrations assayed every 15 minutes.

SETTING

University research center.

ANIMALS

Twenty-four adult female New Zealand white rabbits.

INTERVENTION(S)

Anesthesia, mechanical ventilation, and pneumoperitoneum.

RESULT(S)

The effects of CO(2)-pneumoperitoneum on all end points increased with the elevated intraperitoneal pressure and were more pronounced when ventilation was fixed. Changes were less when 2% or 6% of oxygen had been added to the CO(2)-pneumoperitoneum. With use of logistic regression, the addition of oxygen, intraperitoneal pressure, and ventilation were found to be independent variables affecting Pco(2), pH, ABE, SBE, HCO(3)(-), O(2)Hb, So(2), p50, and end-tidal CO(2).

CONCLUSION(S)

The metabolic consequences of the combined effect of increased intraperitoneal pressure and CO(2)-pneumoperitoneum were less when 2% to 6% of oxygen was added or when animals were hyperventilated. We suggest that metabolic and mesothelial hypoxemia caused by CO(2) absorption can be reduced by adding small amounts of oxygen and by hyperventilation.

Impact of adhesions in colorectal surgery

The extent of the problem of adhesions is considerable and poses a significant burden on healthcare systems, the workload of surgeons and the lives of patients. This paper reviews the work undertaken and the associated evidence for the impact of adhesions. It considers the various options and strategies to reduce adhesions alongside the fundamental necessity for good surgical technique.

Postoperative intraperitoneal adhesion pathophysiology

Aside from the normal 'ad integrum' peritoneal regeneration, the postoperative intraperitoneal adhesion formation process may be considered as the pathological part of peritoneal healing following any injury, particularly a surgical one. Despite a large body of clinical and experimental studies, its pathophysiology remains controversial. Moreover, a better understanding of the pathophysiological events and of the medical and surgical factors involved in the adhesion formation process is pivotal in any attempt to control this very frequent phenomenon and its serious consequences.

Female infertility and free radicals: potential role in adhesions and endometriosis

Free radicals are highly reactive molecules produced in the cell either as part of, or as end-products of, biochemical reactions that have crucial roles in the homeostasis of the organism. Thus, excess production or impaired elimination of free radicals leads to increased oxidative stress, which has been implicated in the development of several different disease states, including hypoxia-reperfusion injury, cancer, and aging. Peritoneal adhesions and endometriosis are relatively commonly identified in women, and are known to be associated with infertility without clearly understood pathophysiology. The prevention and treatment strategies of these conditions, both of which have tremendous propensity to recur, have not been completely established. The development of both disorders has been shown to be closely related to the presence of increased oxidative stress in the tissues. In this article, we review this relationship with reference to the mechanistic steps involved and their regulation. As our knowledge of both conditions expands, we believe there will be opportunities for specific steps to intervention in free radical metabolism to reduce and/or prevent further development of endometriosis and adhesions.

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.

Role of CO2 pneumoperitoneum-induced acidosis in CO2 pneumoperitoneum-enhanced adhesion formation in mice

The effect of assisted ventilation and CO(2) pneumoperitoneum during laparoscopic surgery upon blood gases and adhesion formation were evaluated in mice. We confirmed that the CO(2) pneumoperitoneum induces acidosis and enhances adhesion formation, and an association between both effects was demonstrated, together with its modulation by the assisted ventilation.

Endometriosis: modern surgical management to improve fertility

Endometriosis is a pleiotropic reproductive condition and the lesions visualized at laparoscopy are only one aspect of this disease process. At present, there is no evidence that surgery for endometriosis can cure infertility. The most important surgery in infertility is ovarian surgery. It is generally accepted that, in most cases, the invagination of the cortex results in the formation of an endometriotic pseudocyst. As a consequence, primordial follicles are present at the base of the cyst. Since surgery is of limited value, the utmost care has to be given to conservation of the patient's fertility. Ablative surgery offers advantages over excision of the cyst in terms of less adhesion formation and better preservation of the ovarian reserve. The ablative eversion technique differs from fenestration and drainage by its access through the site of inversion and resection of the fibrotic ring. Using the new technique of transvaginal hydrolaparoscopy, access to the site of pathology in the fossa ovarica is facilitated. Furthermore, the aqueous distension medium keeps the organs afloat and provides a clear delineation between the organs and adhesions allowing atraumatic reconstructive surgery.

Comparison of peritoneal oxidative stress during laparoscopy and laparotomy

STUDY OBJECTIVE

To identify oxidative stress in peritoneum during laparoscopic and open surgery by measuring products of lipid peroxidation, and to determine whether surgical approach influences the type of oxidative metabolite synthesized.

DESIGN

Retrospective analysis (Canadian Task Force classification II-2).

SETTING

University-affiliated hospital.

PATIENTS

Twenty-eight consecutive women with uterine myomas or ovarian cysts.

INTERVENTION

Laparoscopic or open surgery (14 patients each).

MEASUREMENTS AND MAIN RESULTS

We obtained 1 x 1-cm squares of peritoneum at the beginning and end of surgical procedures away from sites of surgery. 8-Isoprostaglandin F(2alpha), hydroxyeicosatetranoic acids (HETEs), and malondyaldehyde (MDA) were measured by enzyme-immunoassay, high-performance liquid chromatography, and thiobarbituric acid adduction method, respectively. Comparisons showed significant increases in 5-HETE and 8-prostane in the laparoscopy group, which were correlated with duration of pneumoperitoneum and volume of carbon dioxide (CO(2)) insufflated, respectively. In the laparotomy group only MDA rose significantly related to duration of surgery.

CONCLUSIONS

Lipid peroxidation was observed in peripheral peritoneum during laparoscopic surgery, mediated through noncyclooxygenase and lipoxygenase pathways, and appears to be due to effects of CO(2) pneumoperitoneum. Biochemical reactions were also observed in the laparotomy group, but are thought to be related to mechanisms other than lipid peroxidation.

Minimally invasive exploration of the female reproductive tract in infertility

Classically, invasive and non-invasive tests are performed to evaluate the causes of infertility. Transvaginal hydrolaparoscopy (THL) allows the exploration of the pelvic structures with a mini-endoscope, using a vaginal needle-guided trocar introduction technique and saline as a distension medium. A first study on 349 patients demonstrated the feasibility of the procedure and gave a high patient satisfaction. Access to the pouch of Douglas was achieved in 330 patients (94.5%) under local anaesthesia and in an ambulatory environment. The mean pain score measured on a visual analogue scale of 10 was 2.7, comparable to the score of mini-hysteroscopy only and significantly lower than the scores of hysterosalpingography with either metal cannula or balloon catheter. A total of 96% of the patients agreed to repeat the procedure under the same circumstances if required. The diagnostic accuracy of the technique was demonstrated in a prospective study, in which two independent endoscopists explored 10 patients with both THL and standard laparoscopy. The inter-observer agreement for ovarian adhesions was 75% for standard laparoscopy and 90% for THL. In addition, in patients with mild endometriosis, more peri-ovarian adhesions were detected with THL than with standard laparoscopy. A multinational survey to evaluate the risk and outcome of bowel injury during THL registered 24 (0.65%) cases in 3667 procedures. In all cases, the diagnosis was made immediately and the treatment was conservative without complications.

Experience with transvaginal hydrolaparoscopy for reconstructive tubo-ovarian surgery

The transvaginal approach to tubo-ovarian surgery allows easy and direct access to the tubo-ovarian structures and the fossa ovarica without additional manipulation. In the absence of a panoramic view, the proximity of the tubo-ovarian structures allows operative procedures for treatment of superficial and cystic ovarian endometriosis, drilling of the ovarian capsule, adhesiolysis and salpingostomy. Operative procedures were performed in 78 patients. No conversion to standard laparoscopy was necessary, and no complications occurred. All procedures were carried out on an ambulatory basis with a very low morbidity.

Peritoneal mesothelial hypoxia during pneumoperitoneum is a cofactor in adhesion formation in a laparoscopic mouse model

OBJECTIVE

To develop a laparoscopic mouse model to evaluate the hypothesis that mesothelial hypoxia during pneumoperitoneum is a cofactor in adhesion formation.

DESIGN

Prospective randomized trials.

SETTING

Academic research center.

ANIMAL(S)

One hundred thirty female Naval Medical Research Institute (NMRI) mice.

INTERVENTION(S)

Adhesions were induced by opposing monopolar lesions in uterine horns and pelvic side walls during laparoscopy and evaluated after 7 or 28 days under microscopic vision during laparotomy. The following pneumoperitoneum variables were assessed: duration (10 or 60 minutes), insufflation pressure (5 or 15 cm of water), insufflation gas (CO(2) or helium), and addition of oxygen (0-12%).

MAIN OUTCOME MEASURE(S)

Adhesions were scored quantitatively and qualitatively for extent, type, and tenacity.

RESULT(S)

Scoring of adhesions 7 or 28 days after laparoscopic surgery was comparable. Adhesions increased with duration of pneumoperitoneum and with insufflation pressure and decreased with the addition of oxygen. Half-maximal reduction of adhesions was obtained at 1.5% oxygen, whereas a maximal reduction required only 2%-3%. The effect of CO(2) and helium was similar.

CONCLUSION(S)

These data demonstrate the feasibility of the intubated laparoscopic mouse model and confirm previous observations in rabbits, indicating that mesothelial hypoxia plays a key role in adhesion formation.

Pain after laparoscopic cholecystectomy

BACKGROUND

Although laparoscopic cholecystectomy (LC) results in less pain than open chole-cystectomy, it is not a pain-free procedure. Many methods of analgesia for pain after laparoscopy have been evaluated.

METHODS

Forty-two randomized controlled trials assessing interventions to reduce pain after LC are reviewed, as are the mechanisms and nature of pain after this procedure.

RESULTS

Non-steroidal anti-inflammatory drugs, wound local anaesthetic, intraperitoneal local anaesthetic, intraperitoneal saline, a gas drain, heated gas, low-pressure gas and nitrous oxide pneumo-peritoneum have been shown to reduce pain after LC. The clinical significance of this pain reduction is questionable.

CONCLUSION

Pain after LC is multifactorial. Although many methods of analgesia produce short-term benefit, this does not equate with earlier discharge or improved postoperative function. However, single trials evaluating low-pressure insufflation, heated gas and multimodal analgesia suggest that clinically relevant benefits can be achieved.

Adhesion formation in intubated rabbits increases with high insufflation pressure during endoscopic surgery

The aim of the study was to test the hypothesis that the increase in adhesion formation by CO(2) pneumoperitoneum is caused by mesothelial hypoxaemia. Therefore the effect of the intra-abdominal pressure together with the flow rate upon adhesion formation was evaluated in rabbits following laser and bipolar lesions during endoscopic surgery using humidified CO(2) at 35 +/- 1 degrees C. The intra-abdominal pressure and flow rate were 5 mmHg and 1 l/min in group 1 (n = 5), 5 mmHg and 10 l/min in group 2 (n = 4), 20 mmHg and 1 l/min in group 3 (n = 5) and 20 mmHg and 10 l/min in group 4 (n = 4) respectively. A rapid and reliable intubation method for rabbits was developed to permit high insufflation pressure. By two-way analysis of variance, total adhesion scores following a laser lesion increased with flow rate (P = 0.0003) and insufflation pressure (P = 0.002). Total adhesion scores of bipolar lesions increased with pressure (P = 0.02) but not with flow rate (P = 0.1). The total adhesion scores of laser and bipolar lesions together increased with flow rate (P = 0.005) and with insufflation pressure (P = 0.004). There was no statistical interaction between flow rate and insufflation pressure. In conclusion, the insufflation pressure in endoscopic surgery with CO(2) pneumoperitoneum is a co-factor in adhesion formation, together with desiccation.

Office transvaginal hydrolaparoscopy for early diagnosis of pelvic endometriosis and adhesions

STUDY OBJECTIVE. To evaluate the feasibility of a new endoscopic technique, transvaginal hydrolaparoscopy, for early office screening of subfertile women. DESIGN. Retrospective, descriptive feasibility study (Canadian Task Force classification II-2).

SETTING

Office in an infertility center.

PATIENTS

One hundred fifty-seven continuous women with primary or secondary subfertility.

INTERVENTION

Under local anesthesia, a Veress needle-cannula system was inserted into the posterior fornix with peritoneal distention by saline.

MEASUREMENTS AND MAIN RESULTS

Access was achieved in 95% of patients. In 58.5% the findings were normal and in 28% an explorative or operative laparoscopy was indicated. No major complication occurred. Patients' pain scores were similar to those for office hysteroscopy.

CONCLUSION

Transvaginal hydrolaparoscopy was successfully performed in the office. The technique allows early and complete endoscopic screening of subfertile women.

Office hydrolaparoscopy for the diagnosis of endometriosis and tubal infertility

Transvaginal hydrolaparoscopy has been described as an office procedure that is particularly suitable for the diagnosis of endometriosis and adhesions. It is recommended as a first line procedure in patients with infertility. The procedure is performed under local anaesthesia or sedation in an office setting. The abdominal distension is achieved by transvaginal instillation of warm saline using a combined Veress needle-trocar system. The exploration under fluid allows the inspection of the tubo-ovarian structures in their natural position and the easy identification of endometriotic lesions and adhesions in the posterior pelvis. The limitation of the inspection to the posterior pelvis is not a major problem for the diagnosis of endometriosis because exclusively anterior pelvis endometriosis is rare and of doubtful significance in infertility. Transvaginal hydrolaparoscopy can be performed in the office setting in combination with minihysteroscopy, tubal patency test and salpingoscopy, offering major advantages for the diagnosis of pelvic disease in patients with infertility.

Adhesion formation after microlaparoscopic and laparoscopic ovarian coagulation for polycystic ovary disease

STUDY OBJECTIVE

To compare the effects of microlaparoscopy and decreased CO2 exposure on peritoneal microcirculation and potential adhesion formation after ovarian surgery with those of conventional operative laparoscopy.

DESIGN

Prospective, randomized study (Canadian Task Force classification I).

SETTING

Teaching hospital.

PATIENTS

Eighteen women with polycystic ovary disease.

INTERVENTIONS

Microlaparoscopic or laparoscopic ovarian coagulation of the ovaries.

MEASUREMENTS AND MAIN RESULTS

Approximately 10 to 12 coagulation points were applied to each ovary. Two to 3 weeks after the initial surgery second-look microlaparoscopy was performed to determine the extent of adhesions in both groups. The frequency of adhesion formation and changes in glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH) levels were studied in homogenized peritoneal tissues obtained during surgery in each group.

RESULTS

Clinical profiles were similar between groups. Mean exposure, amount, and pressure of CO2 were significantly less in the microlaparoscopy group (p <0.05). The laparoscopy group had significantly more adhesions than the microlaproscopy group (24% vs 48%, p <0.05). The GSH-Px, SOD, CAT, and GSH levels were significantly lower in the laparoscopy group (0. 425 micromol, 1.2 ng, 37.55 micromol, and 0.9 nmol vs 0.755 micromol, 2.l ng, 625 micromol, and 2.6 nmol, respectively).

CONCLUSION

Reduced exposure to and amount of CO2 during microlaparoscopy may result in decreased adhesion formation compared with conventional laparoscopy. This effect may possibly be due to lack of or minimal adverse effects on peritoneal microcirculation and cell-protective systems, which are proposed mechanisms for adhesion formation and closely related to peritoneal injury. In addition, microlaparoscopy may be a cost-effective alternative to conventional laparoscopy. (J Am Assoc Gynecol Laparosc 6(2):159-163, 1999)