Quadratus Lumborum Block (Transmuscular Approach) VS. TransversusAbdominus Plane Block(Unilateral Posterior Approach) for Perioperative Analgesia in Patients Undergoing Flank Incision Surgeries.

Severe perioperative pain experienced after surgical procedures performed by flank incision is mainly related to incision of many muscles. Postoperative pain affects patient comfort, satisfaction, prolongs the duration of hospital stay and increases post-procedure complications. This study is designed to compare the success rate of Unilateral Ultrasound Guided Transmuscular Quadratus Lumborum Block with Unilateral posterior Ultrasound Guided TransversusAbdominus Plane block in providing perioperative analgesia in Patients undergoing Flank Incision surgeries in the Urosurgery Theater at KasrAlainy University Hospitals.

Patients aged from 20-60 years old, scheduled for flank surgery procedure will be included in the study. Patients will be randomly allocated using concealed closed envelope method into one of three groups:

Group A (n=16): will receive USG TransmuscularQLB after induction of general anesthesia.

Group B (n=16): will receive unilateral USG posterior TAP Block after induction of General anesthesia.

Group C (n=16): (control group) will not receive any blocks.general anesthesia will be induced using propofol 2-3 mg/kg over 20-30 seconds, fentanyl 2 µg/kg, and atracurium 0.5 mg/kg to facilitate endotracheal intubation. Anesthesia will be maintained using isoflurane 1.5 %, atracurium at a dose of 0.1 mg/kg every 20 minutes. For all patients, fluid management will be strict according to body weight and blood loss will be adequately estimated and replaced. In the three groups, the observing anesthetist will be advised to give fentanyl increment doses (0.5 µg/kg) when mean blood pressure, heart rate or both increased by more than 20% from the baseline, lacrimation or sweating (signs of inadequate analgesia).

Postoperatively, all patients will receive IV paracetamol 1gm every 8 hours. As a rescue analgesic, meperidine (0.5 mg/kg) will be used when VAS score \> 4. The following data will be recorded1- Duration of the surgery 2- Time required to perform the blocks in minutes 3- Intraoperative mean blood pressure and heart rate will be recorded in all groups immediately after induction, at the surgical incision and every 15 minutes till the end of the procedure.

4- Total amount of intraoperative fentanyl consumption will be recorded 5- Immediate postoperative blood pressure and heart rate will be recorded 6- Visual Analogue scale (VAS) for pain will be applied postoperatively at rest and during movement. Pain will be assessed with a 10-cm ruler ranging from no pain (0) to severe pain (10). Evaluation will be performed immediately postoperative, at 30 minutes, 1 hour, 2 hours, 4 hours, 6hours and 12 hours postoperatively.

7- The time of the first analgesic request (rescue analgesia) in the postoperative period will be recorded (defined as the time between the end of surgery and the request of the first dose of postoperative analgesics). As a rescue analgesic, meperidine (0.5 mg/kg) will be used when VAS score \> 4.

8- Postoperative nausea and vomiting

Eligibility Criteria:
Inclusion Criteria:

* Patients age between \>20 and \<60.
* Patients scheduled for Urological flank surgery (open nephrectomy)
* Ability to sign the consent
* ASA classification I, II
* Body Mass Index (BMI) \< or = 30
* Duration of surgery less than 3 hours

Exclusion Criteria:

* Refusal of the regional block.
* Bleeding disorders (INR \>1.4 )( platelet count \<100,000/mm3 )
* Skin lesions or infection at the site of proposed needle insertion.
* Evidence of peritonitis or septicemia.
* Hepatic disease e.g. liver cell failure or hepatic malignancy or hepatic enlargement.
* Patients with ventriculoperitoneal shunts in situ.
* Allergy to amide local anesthetics, fentanyl or meperidine.
* Patients suffering from neurological disease.
* ASA classification \> II
* BMI \> 30
* Duration of surgery more than 3 hours