Patients will have only clear liquids after a normal breakfast and lunch on the day before surgery and subsequently fasten for 7-9 hours prior to surgery. Patients will ingest first dose of 45 ml oral sodium phosphate (NaP) enema (BT ORAL SOLUSYON 45 ML®, Yenisehir Lab. Tic. San. Ltd. Sti, Turkey) at 4 p.m. and a second dose at 8 p.m. in the evening before the scheduled surgery.

Patients will be given detailed instructions about the pre-operative diet (total daily Fibre intake inferior to 10 g) to be used for 3 days prior to surgery.

This group will receive both mechanical bowel preparation and 3-days low fibre diet.

Control subjects will receive no instructions about the pre-operative diet (free diet).

oral sodium phosphate (NaP) enema

A scale title as "Objective Visual Indexing (OVI)" will be used for assessing the visibility of the Douglas pouch and adnexa. The assessment of the visibility of Douglas pouch and adnexa will be performed under standard pneumoperitoneum pressure (12mmHg) and Trendelenburg inclincation angle (30). After the first Inspection, scale of VI scoring will be calculated by adding up the points obtained from optical inspection. Higher scores mean better visuality of the surgical field.

The PP will be increased to 15 mmHg while keeping the TIA same, at 30o. The surgeon will displace the bowel beginning from the cecum followed by the last ileal loop above the sacral promontory. Once the bowel was displaced out of the pelvis, the PP will be stepwise decreased by 1 mmHg during 1 min intervals to the lowest pressure where the bowel is to descend towards the pelvis over the pelvic brim and/or where the surgical workspace is not adequate to proceed safely with the planned operation. This value will be recorded as the lowest PP adequate to proceed safely with the planned surgery at standard TIA (30 degree).

The PP obtained in outcome 2 will be readjusted to the standard 12 mmHg keeping the TIA same, at 300. Then, the surgeon will replace the bowel beginning from the cecum followed by the last ileal loop above the sacral promontory. Once the bowel is displaced out of the pelvis, the TIA will be gradually decreased by 1o with 15 seconds intervals to the degree where the bowel is to descend towards the pelvis over the pelvic brim. This value will be recorded as the lowest TIA adequate to proceed safely with the planned surgery at standard PP (12 mmHg).

Patients will be interviewed in the preoperative holding area or in the patient's room about the acceptability of the intervention (MBP / diet) and adverse pre-operative events, including: nausea, insomnia, headache, thirst, weakness, tiredness, discomfort, abdominal cramps, sleep disturbances. These symptoms will be scored with using a 10-cm "Visual Analog Score" (VAS). Higher scores mean worse outcome.