prone flexed position in percutanous nephrolithotomy in comparsion with standard prone position. A randomized controlled trial.

Patients meeting the inclusion criteria will be randomly allocated to 2 groups:

1. 1st group will undergo prone-flexed PCNL.
2. 2nd group will undergo prone PCNL.

III. Recruitment of participants Patients appointed for an outpatient diagnostic cystoscopy will be reviewed for the inclusion and exclusion criteria. Legible patients will be asked to participate in the study and to sign the informed consent form.

IV. Randomisation Randomization will be performed using computer generated random tables using stratified blocked randomization in 1:1 ratio.

V. Study procedure Preoperative evaluations included

1. Detailed medical history
2. Physical examination
3. Routine blood examination
4. Urinalysis & urine cytology
5. Renal and liver function tests
6. Coagulation profile

8. Computed tomography of the abdomen and pelvis

Operative Technique

Prone-flexed positioning i. Retrograde access will be obtained ii. The patient is repositioned prone with adequate padding under the pressure points of the head, chest, knees, and feet.

iii. The table is flexed 30 degrees at the level of the patient's mid lumbar region to open the space between the 12th rib and the posterior iliac crest dropping the gluteal muscles from the working plane.

Ancillary intervention

Patients will receive a 20-mL infiltration of 0.25% bupivacaine. Under fluoroscopic guidance, the local analgesic was infiltrated with a 22-gauge spinal needle (10-cm length) along the nephrostomy tract at the 3, 6, 9, and 12 o'clock positions (5 mL in each tract), including the muscles, subcutaneous tissue, and skin.

Patients will receive 1 g tranexamic acid at induction followed by three further doses of 500 mg over the next 24 h.

Inclusion Criteria:

• Large renal or upper ureteral calculi or both,

Exclusion Criteria:

• (1) Age <18 years or Pregnancy (2) Ureter pelvic junction obstruction (3) Bilateral simultaneous PCNL (4) Need for 3 percutaneous tracts intraoperative (5) Morbid obesity (BMI >40) (6) Non opaque renal stones. (7)Refuse to complete study requirements (8)Untreated UTI (9)Atypical bowel interposition by CT (10)Tumour in the presumptive access tract area or Potential malignant kidney tumour