Primary breast cancer surgery is one of the most commonly performed surgeries worldwide. It is associated with significant acute postoperative pain and a high incidence of chronic postsurgical pain. Regional anaesthetic techniques are shown to improve outcomes such as postoperative analgesia, nausea, vomiting, delirium and promote early recovery. Currently majority of the breast cancer surgery is performed under general anaesthesia with a multimodal analgesic regimen with or without regional blocks. In fact, it is proved that breast cancer surgery can be done solely under regional anesthesia using multilevel thoracic paravertebral block (TPVB) with deep sedation, but rescue analgesia are often required intraoperatively, especially when surgeons handles the pectoralis muscle. Current evidence suggest that pectoral nerves, which are often described as a pure motor nerves that control movements only, also able to send noxious stimulation such as pain from the pectoral muscles and its deep fascia (via afferent nociceptive fibers) to the brain. Principal investigator proposes that adding a subpectoral plexus block (SPPB) will stop a wider spectrum of afferent nociceptive fibers from sending any pain signals than having thoracic paravertebral block alone. However, there is no report on the amount of local anaesthetic (LA) required to achieve surgical anaesthesia for breast surgery. The aim of this study is to evaluate the effectiveness of two different doses (10ml vs 20ml of 0.25% levobupivacaine) of local anaesthetic (LA) for subpectoral plexus in addition to 3 levels of TPVB injections at T2, T4, and T6 under ultrasound guidance for surgical anaesthesia for major breast cancer surgery.
