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The primary purpose is to compare the impacts of intraperitoneal pressure (8mmHg versus 12 mmHg) and CO2 gas (cool, dry CO2 gas versus warmed, humidified CO2 gas) on gene expression in peritoneal tissues during laparoscopic surgery. We hypothesize that combined use of a low Intraperitoneal pressure (8mmHg) and warmed, humidified CO2 gas during CO2 pneumoperitoneum may be better in minimizing adverse effects on surgical peritoneal environment and improving clinical outcomes compared to the standard intraperitoneal pressure (12mmHg) and standard cool, dry CO2 gas.

Patients undergoing laparoscopic hysterectomy with promontofixation are randomized into four groups: Group 1: 12mmHg intraperitoneal pressure with cool, dry CO2 gas (n=20), Group 2: 12mmHg intraperitoneal pressure with warmed, humidified CO2 gas (n=20), Group 3: 8mmHg intraperitoneal pressure with cool, dry CO2 gas (n=20), Group 4: 8mmHg intraperitoneal pressure with warmed, humidified CO2 gas (n=20).

Normal peritoneum is collected from the parietal wall at the beginning of laparoscopic surgery and at 1 and 2 hours. Expression of genes encoding components of the fibrinolytic system, extracellular matrix and adhesion molecules, and inflammatory cytokine signaling molecules in peritoneal tissues are measured by real-time PCR.

Quality of post-operative recovery by QoR-40, post-operative pain by Visual Analog Scale, per or post operative complications and intraoperative core temperature are assessed and compared.

Inclusion Criteria:

• Age 45-75 years old
• Petients undergoing laparoscopic hysterectomy with promontofixation for uterine prolapse
• Menopaused
• ASA class I or II

Exclusion Criteria:

• Absolute contraindications to laparoscopy
• Previous history of pelvic surgery, endometriosis and/or infection
• Pathological peritoneal tissue
• BMI more than 30
• Height less than 150cm