Overview Analgesic Effect to Postoperative Pain After Mastectomy: Ultrasound-guided Serratus Anterior Plane Block Status: Completed Trial end date: 2016-02-28 Target enrollment: Participant gender: Summary Ultrasound guided serratus anterior plane block may decrease acute postoperative pain and consumption of opioid after mastectomy. Phase: N/A Details Lead Sponsor: Yonsei UniversityTreatments: Ropivacaine