Effectiveness of additional thoracic paravertebral block in improving anesthetic effects of regional anesthesia for proximal humeral fracture surgery in elderly patients: study protocol for a randomized controlled trial

Background: The innervation of shoulder-upper extremity area is complicated and unclear. Regional anesthesia with brachial plexus and cervical plexus block is probably inadequate for the proximal humeral surgery. Missing blockade of T1-T2 nerves may be the reason. We conduct this prospective randomized controlled trial (RCT) to explore whether additional T2 thoracic paravertebral block (TPVB) can improve the success rate of regional anesthesia for elderly patients in proximal humeral fracture surgery. Methods: The patients aged 65 or older, referred for anterior approach proximal humeral fracture surgery, will be enrolled. Each patient will be randomly assigned 1:1 to receive IC block (combined interscalene brachial plexus with superficial cervical plexus block) or ICTP block (combined thoracic paravertebral block with brachial plexus and superficial cervical plexus block). The primary outcome is the success rate of regional anesthesia without rescue analgesic methods. The secondary outcomes are as follows: sensory block at surgical area, proportion of patients who need rescue anesthesia (intravenous remifentanil or conversion to general anesthesia), cumulative doses of intraoperative vasoactive medications and adverse events. The total sample size is estimated to be 80 patients. Discussion: This RCT aims to confirm whether additional T2 TPVB can provide better anesthetic effects of regional anesthesia with brachial and cervical plexus block in elderly patients undergoing proximal humeral surgery.