Serratus Muscle Block for Analgesia after Mastectomy

Abstract

Regional anesthesia has been believed as one of the formats for effective perioperative pain control. Regional blocks using ultrasound-guide has become a perfect supplement to general anesthesia for extending analgesia after modified radical mastectomy. The advantage includes post-operative pain relief prolongation, a decrease in analgesic requirement post-operatively, a reduction in nausea and vomiting scores and probability for ambulatory discharge and hospital stay. The serratus anterior is a fan-shaped muscle that originates on the superolateral surfaces of the first to eighth ribs or the first to ninth ribs at the lateral wall of the thorax and inserts along the superior angle, medial border, and inferior angle of the scapula. The main part of the serratus anterior lies deep to the scapula and the pectoral muscles and is easily palpated between the pectoralis major and latissimus dorsi muscles. This large muscle is generally divided into 3 distinct parts according to the points of insertion: serratus anterior superior (insertion near the superior angle), serratus anterior intermediate (insertion along the medial border), and serratus anterior inferior (insertion near the inferior angle). Breast surgery, especially radical mastectomy, is often accompanied by moderate to severe acute pain, which significantly reduces postoperative quality of life. Effective pain management can accelerate patient recovery. Serratus anterior plane block (SAPB) is a new type of fascial plane block technique, which can better target the nerve network innervating the chest wall and breast and provide good analgesia in the anterolateral chest wall. Current clinical research evidence indicates that SAPB has significant benefits in breast surgery.