Safety and efficacy of ultrasound-guided superior hypogastric plexus block combined with conscious sedation in ambulatory patients undergoing percutaneous microwave ablation of uterine myomas: Study protocol for a single-center, double-blinded, randomized controlled trial.

Background: Pain is a major challenge in performing ultrasound-guided percutaneous microwave ablation (PMWA) of uterine myomas. Inadequate analgesia by local anesthetics hinders the possibility of conducting PMWA of uterine myomas in the Ambulatory Surgery Center (ASC) of the Department of Ultrasound.

Objective: The superior hypogastric plexus (SHP) forms a suitable target for pain relief through the blockade, as it contains nociceptive afferent fibers from pelvic organs such as the uterus, rectum, and bladder. Superior hypogastric plexus block (SHPB) has demonstrated promise as an alternative treatment option for alleviating pelvic pain, reducing opioid consumption, and improving quality of life. This study aims to evaluate the efficacy of ultrasound-guided SHPB combined with conscious sedation as an alternative anesthesia option for ambulatory patients receiving ultrasound-guided PMWA of uterine myomas.

Methods And Analysis: This randomized controlled trial (RCT) will be carried out at the Department of Ultrasound, The First Affiliated Hospital of Xiamen University. Women scheduled for ultrasound-guided PMWA of uterine myomas will be eligible. 86 patients will be recruited and randomly assigned to either the intervention or control groups in a 1:1 ratio. The intervention group will undergo ultrasound-guided superior hypogastric plexus block (SHPB) combined with conscious sedation, while the control group will receive local anesthesia combined with conscious sedation. The primary outcome is the success rate of anesthesia, secondary outcomes include vasoactive drug consumption, acetaminophen consumption, sleep quality, sonographer satisfaction score, patient satisfaction score, the detained time in hospital, and adverse events.

Discussions: This RCT represents the inaugural effort to specifically evaluate the safety and efficacy of ultrasound-guided SHPB combined with conscious sedation in patients undergoing ultrasound-guided PMWA of uterine myomas and will provide valuable evidence and insight into the analgesic management of this ambulatory surgery.

Ethics And Dissemination: This study has been approved by the Ethics Committee of the First Affiliated Hospital of Xiamen University (Scientific Research Ethics Review 2023, No. 139). The results will be submitted for publication in peer-reviewed journals.