Comparison of Interscalene Catheter to Single Injection Interscalene Blocks for Total Shoulder Arthroplasties

This study compares two nerve block approaches for pain control after reverse shoulder replacement surgery: a single-injection interscalene nerve block (one-time numbing injection near the neck) versus a continuous interscalene nerve block catheter (a small tube left in place that delivers ongoing pain medication for days). Shoulder replacement is a major surgery with significant post-operative pain, and effective nerve blocks can reduce the need for opioid medications. The question is whether the sustained relief from a catheter justifies its additional complexity compared to a simpler one-time injection. Eligible participants are adults aged 18–89 undergoing elective reverse shoulder replacement, classified as ASA I–III (meaning reasonably healthy), who give informed consent and are suitable for regional anesthesia. People with contraindications to nerve blocks (such as those on blood thinners), severe lung disease, allergy to the local anesthetics used, nerve damage in the arm being operated on, kidney or liver failure, pregnancy, inability to communicate in English, chronic high opioid use, or those undergoing fracture repair or revision surgery are excluded. Participants will be randomized to one of the two block types and followed for pain scores, opioid use, and any complications. This research is important because shoulder arthroplasty is one of the fastest-growing orthopedic procedures in the U.S., and optimizing post-operative pain management directly affects recovery speed, opioid exposure, and patient satisfaction.