Total abdominal hysterectomy (TAH) is a major surgical procedure after which significant post-operative pain and discomfort are anticipated. Abdominal field blocks have been followed for many years and extensively used for pain management following abdominal surgeries such as laparotomies and appendicectomies. Erector Spinae Plane Block (ESPB)-first recently described for the treatment of thoracic neuropathic pain, is a peri-paravertebral regional anesthesia technique that has since been reported as an effective technique for prevention of postoperative pain in various surgeries. Intrathecal opioid administration is an attractive analgesic technique since the opioid is injected directly into the cerebrospinal fluid, close to the structures of the central nervous system where the opioid acts.

Inclusion Criteria:

• Body mass index (BMI) 25 to 35kg/m².
• American Society of Anesthesiologist (ASA) physical status I or II.

Exclusion Criteria:

• patient's refusal
• Altered mental status
• Known allergy to study drugs (bupivacaine or morphine)
• Local infection at site of puncture.
• Known case with any pulmonary disease
• Known case with Obstructive sleep apnea (OSA)
• Coagulopathy and /or thrombocytopenia
• Chronic pain
• Severe hepatic or kidney impairment