Transversalis Fascia Plane Block Versus Intrathecal Morphine for Postoperative Analgesia in Total Abdominal Hysterectomy

Total abdominal hysterectomy (TAH) is a commonly performed major surgical procedure that results in substantial postoperative pain and discomfort. Postoperative pain, if not treated promptly, can impair the patient's ability to ambulate which may lead to adverse effects such as thromboembolism, myocardial ischemia, and arrhythmia.

Intrathecal opioids are synergistic with local anesthetics and intensify the sensory block without increasing the sympathetic block. Morphine, which is relatively less hydrophobic than other opioids, has a longer residence time in the cerebrospinal fluid and therefore may reach rostral sites over a longer period than other opioids.

Ultrasound-guided interfascial plane blocks are often used in multimodal analgesia regimens. Local anaesthetic injection into the transversalis fascia plane (TFP) anesthetizes the proximal branches of T12 and L1 which targeted in the plane between the transversus abdominis muscle and the transversalis fascia.

• Transversalis fascia plane block (Other): Patients will receive spinal anesthesia (using 3.5 mL of hyperbaric bupivacaine 0.5%) with bilateral transversalis fascia plane (TFP) block (using 20 mL of bupivacaine 0.25%) at the end of surgery.
• Morphine (Drug): Patients will receive spinal anesthesia (using 3 mL of hyperbaric bupivacaine 0.5%) + (75 µg morphine diluted in 0.5ml saline) with sham block at the end of surgery.

Primary outcomes

• Time to the 1st rescue analgesia [24 hours postoperatively]: Time to the first request for the rescue analgesia (time from the end of surgery to first dose of morphine administrated).

Secondary outcomes

• Total morphine consumption [24 hours postoperatively]: Rescue analgesia of morphine will be given as 3 mg bolus if the numeric rating scale (NRS)> 3 to be repeated after 30 min if pain persists until the NRS < 4.
• Degree of pain [24 hours postoperatively]: Each patient will be instructed about postoperative pain assessment with the numeric rating scale (NRS). NRS (0 represents "no pain" while 10 represents "the worst pain imaginable"). NRS will be assessed at post-anesthesia care unit (PACU), 2, 4, 6, 8, 12, 18, and 24 h postoperatively.
• Incidence of adverse events [24 hours postoperatively]: Incidence of adverse events such as bradycardia, hypotension, pruritis, nausea, vomiting, respiratory depression, or any other complication will be recorded.

Sex: All, ages: 18 Years to 65 Years

Inclusion Criteria:

* Age from 18 to 65 years.
* American Society of Anesthesiology (ASA) physical status I-II.
* Women undergoing total abdominal hysterectomy (TAH) under spinal anesthesia.

Exclusion Criteria:

* History of allergies to local anesthetics.
* Local infection at the site of injection.
* Bleeding disorders.
* History of chronic use of analgesic.
* Physical or mental conditions.
* Hepatic, renal or cardiac disease.
* Contraindication to spinal anesthesia.