Continuous regional anesthesia: a review of perioperative outcome benefits.

Routine use of regional anesthesia for patients having surgery is supported by general safety and proven effectiveness as a targeted modality in the prevention and treatment of acute pain. Recently, perioperative physicians have become much more interested in improving long-term outcomes after surgery rather than focusing on the well-established short-term benefits of regional anesthesia. This interest has raised important questions regarding the potential influence of regional anesthesia on morbidity and mortality, persistent pain and cancer prognosis. Tissue injury is responsible for the inflammatory reaction and physiologic stress response observed during the perioperative period and can influence a patient's recovery trajectory. Regional anesthesia can modulate the inflammatory response through the direct anti-inflammatory effect of local anesthetics, blocking neural afferents, and blunting sympathetic activation. Moreover, continuous techniques (e.g., epidural and perineural catheters) that provide longer duration and titratable pain relief in the perioperative period may be protective against the development of persistent post-surgical pain by providing effective acute pain management and decreasing exposure to opioids. To maximize the potential for long-term outcome benefits to surgical patients, continuous regional anesthesia techniques are preferred over single injection techniques. Although the data are not yet definitive, some studies have demonstrated better functional recovery after joint replacement and lower rates of cancer recurrence in patients treated with continuous regional anesthesia. Future research studies in regional anesthesia will have to focus on these long-term patient-centered outcomes and may need to incorporate novel study designs and analyses of big data.