Shoulder surgery is a growing field in geriatric orthopedics and sports medicine. Surgical methods are applied to diseases where non-invasive treatment techniques have failed. In recent years, the efficacy of peripheral nerve blocks has been repeatedly compared, but studies have focused primarily on their postoperative effects without evaluating intraoperative analgesia and opioid consumption.Aim: The aim of this study was to evaluate the benefits of preoperatively administered ISPB in terms of intraoperative pain control and total intraoperative opioid analgesic consumption.Materials and Methods: A total of 89 patients undergoing open shoulder surgery were included in this study. Of these, 21 underwent shoulder joint replacement surgery, 59 underwent surgery for proximal humeral fracture, and 9 patients underwent open shoulder surgery other than the above-mentioned. Preoperatively, 57 patients underwent ISPB, and 32 patients were without a brachial plexus block. The study was prospective and retrospective because we obtained the data of patients without preoperative ISPB from the hospital records.Results: Administered preoperatively, the ISPB effectively reduced intraoperative opioid analgesic consumption during open shoulder joint and proximal humerus surgery.Conclusion: Interscalene plexus block is an excellent adjunct to multimodal analgesia, not only for postoperative pain control but also as part of intraoperative analgesia