Anesthesia for Arthroscopic Shoulder Surgery

Arthroscopic shoulder surgery is a minimally invasive technique that effectively treats certain diseases and injuries of the shoulder joint. Indeed, new lesions and surgical techniques for their treatment have also been discovered by using this approach. Controlling post-operative pain in shoulder surgery facilitates early mobilization and fast functional recovery, allowing pain-free muscle contraction. Tissue injury due to the surgical intervention results in the release of many chemical mediators that activate and increase the excitability of nociceptors, producing intraand post-operative hyperalgesia. Local anesthesia can be used more frequently for less aggressive surgical techniques, particularly in limb surgery, both for intra-operative and post-operative pain. It is essential to be familiar with the anatomy of the region to be anesthetized in order to minimize the potential risks and recognize them when they occur. The upper limb is innervated by the arms of the cervical spinal nerves (C5-C8) and part of the ventral branch of T1, although anatomical variations may exist. All these sensory, motor and vegetative nerve fibers form an "anastomotic complex of fibers", known as the brachial plexus. The block of the brachial plexus was first developed in 1884, when Halstead injected cocaine into the exposed roots of the brachial plexus (1). However, it was not until 1911 that Hirschel and Kulenkampff described the percutaneous brachial plexus block first developing the axillary technique and then, the supraclavicular route (2,3). In 1919, Mulley developed a technique aimed at preventing pneumothorax by employing interscalenic approach to the brachial plexus (4). The modern interscalenic approach was perfected by Winnie, using the transverse processes of the 6th cervical vertebra (5) as a reference for needle insertion. Anesthetic options for shoulder arthroscopic surgery include: general anesthesia, regional anesthesia with or without sedation, and a combination of both general and regional anaesthesia. Regional anesthesia offers many advantages over general anesthesia for arthroscopic shoulder surgery. The most notable advantage is the ability to control perioperative pain by proximally blocking the brachial plexus (supraclavicular approaches). The "Preemptive" analgesia afforded by the blockade and the excellent analgesic conditions can overt the need for intraoperative opioid administration. The patients' perception of pain-free surgery represents a further advantage of this approach. Together, this facilitates earlier hospital discharge with the attendant reduction in the economic cost of the procedure (6,7).