The intent of this study is to compare the efficacy of the erector spinae plane block (ESPB) and paravertebral plane block in reducing postoperative opioid consumption and pain in patients with total abdominal hysterectomy.

The intent of this study is to compare the efficacy of the erector spinae plane block (ESPB) and paravertebral plane block in reducing postoperative opioid consumption and pain in patients with total abdominal hysterectomy. All patients will be assessed preoperatively by history taking, full physical examination, and laboratory evaluation CBC, coagulation, kidney and liver function. inform the patient about VAS score, On arrival of the patients to the operating room, electrocardiography, non-invasive blood pressure, and pulse oximetry will be applied. the vital signs parameters including mean arterial pressure (MAP), heart rate (HR), respiratory (RR) and SpO2 will be measured every 5 minutes recorded at base line and every 30 minutes till end of surgery. Intravenous (IV) line will be inserted and IV fluids 500ml normal saline will be started.

In the induction of general anesthesia, the patient will receive intravenous fentanyl (2 μg /kg) and propofol (2 mg/kg). atracurium (0.5 mg/kg) then tracheal intubation and the mechanical ventilator will be employed to maintain the end-tidal CO2 between 30 and 35 mmHg. Depending on the requirements of the patient, both inhaled (Sevoflurane) and intravenous (IV) atracurium will be utilized for anesthetic maintenance.

Preparation of local anesthesia 20 ml bupivacaine 0.25% for the block for each side without exceeding the toxic dose 2mg/kg [. then the block will be performed on the lateral position.

Both blocks will be performed under complete aseptic precautions using ultrasound machine with high frequency linear probe covered with sterile sheath.

Group 1(Paravertebral Plane Block) (24 Patients); The spinous process of the 10th thoracic vertebra will be located under the ultrasound guided (USG) linear probe. Under aseptic precautions, a 22-G short-beveled needle will be inserted under ultrasonographic guidance using the in-plane approach and was directed medially between the transverse process (TP) and the pleura. The needle will traverse the superior costotransverse ligament and enter the paravertebral space, where 2 ml of normal saline will be injected. The tip of the needle will be in the paravertebral space, noting the pleura being pushed down. Then, 20 ml of 0.25% bupivacaine will be injected into the paravertebral space under USG visualization.

Group 2 (Erector Spinae Plane Block) (24 Patients); The USG linear probe will be placed Longitudinal 3 cm lateral to T10 transverse process TP. A 22-G short-beveled needle will be inserted in the cephalad to caudal direction through the erector spinae to contact the T10 TP using the in-plane technique. After the needle made contact with TP, the plane will be confirmed by injecting 2ml of saline and depositing 20ml of 0.25% bupivacaine.

Monitor HR & MAP and if any increase more than 20% from the baseline value will receive fentanyl 50 µg IV incremental and recording total dose of fentanyl consumption

All patients receive:

Dexamethasone 8 mg IV and Ondansetron 4 mg IV

Reversal:

Neostigmine 0.05 mg/kg and Atropine 0.02 mg/kg Post-operative settings: At the end of the surgery, the patient will be kept under observation postoperatively in the recovery room for 30 min to monitor vital signs (mean arterial pressure, heart rate, respiratory rate) and the conscious level then will be discharged to the ward to be followed.

Postoperative pain: The assessment of postoperative pain will be evaluated postoperatively in the recovery room on arrival (zero time), after 30 minutes, 2,4,6,8,12,16,20, and 24 hours postoperatively in the surgical ward with visual analogue scale (1-10).

All patients will receive paracetamol 1 gm every 8 hrs. At score of3 or more, rescue analgesic 3 mg morphine iv Will be given. Total analgesic dose of morphine during first 24 hours will be recorded.](streamdown:incomplete-link)

Inclusion Criteria:

• ASA I and ASA II patients.
• Female, 30-60 years of age.
• Scheduled for total abdominal hysterectomy.

Exclusion criteria:

• Patient refusal of procedure or participation in the study.
• Opioid or analgesic abuse.
• Known allergy to study drug.
• Any contraindication of regional anesthesia including:
• Local infection at the site of puncture.
• Having history of hematological disorders, including coagulation abnormality.