A nerve block is the technique of injecting a local anesthetic near specific nerves to provide localized anesthesia during and after a surgical procedure. It is recommended to patients when it can provide sufficient anesthesia for a procedure, as it has fewer risks and side effects compared to general anesthesia, or when it can significantly reduce pain postoperatively. Though nerve blocks are powerful tools, a possible side effect of nerve block is rebound pain, or pain a patient experiences after analgesia wears off.
Rebound pain is typically addressed as early as possible using oral pain medications after the surgical operation. [1] This postoperative pain is typically acute and is clinically significant due to both pain intensity as well as the impact of rebound pain on patients’ quality of recovery via impacting patients’ psychological well-being and their ability to perform normal daily activities. [2] Thus it is important to identify both the biological cause and chemical mechanism of rebound pain after nerve block and to determine how best to address this pain, especially given the addictive nature of opiate analgesics and the public health need to minimize their usage.
A fundamental question posed about rebound pain was whether this pain was simply the result of an “unmasking” of expected nociception in the absence of adequate system analgesia, or if regional anesthesia is in some way responsible for causing an exaggerated nociceptive response. In a 2020 review for the Korean Journal of Anesthesiology, Leyva et al. characterized the majority of the research evidence available about rebound pain as pointing toward the former possibility. That is to say—rebound pain is not likely to be caused by the nerve block itself and is rather an expected postoperative outcome of the surgery itself, felt acutely due to the cessation of regional anesthesia. Leyva et al. suggested that, beyond prescribing an analgesic medication regimen (and initiating this regimen in a timely manner) and educating patients to ensure that they have appropriate expectations for postoperative pain, prolonging the duration of action of the regional anesthesia could also assist in alleviating rebound pain. [2]
As in any case where analgesics must be administered, many clinicians are also concerned about the possibility of rebound pain and subsequent patient analgesic use leading to long-term opioid abuse and addiction. The United States has been and remains in the throes of a deadly opioid crisis, with the Health Resources and Services Administration reporting that more than 130 people died every day from opioid-related drug overdoses last year. [3] In their 2019 review, Dada et al. suggest that a multimodal strategy may be prudent in preventing and managing postoperative and post-nerve block pain severe enough to require extended use of opioid analgesics, including preemptive opioid analgesia applied before the nerve block wears off, the use of intra-articular or intravenous steroidal and nonsteroidal anti-inflammatory drugs, lengthening the period of analgesia through the use of adjuvants in nerve block solutions, and the use of continuous blocks (as opposed to single shot nerve blocks). [4]
Despite the clinical significance of rebound pain after nerve block , the issue remains under-addressed and under-researched. As a result, despite some concerted efforts to fill the gap in our understanding about what puts some patients at greater risk of experiencing rebound pain,5 it is difficult for clinicians to predict when serious rebound pain might occur and thus difficult for them to adequately inform patients about the chance of their experiencing this postoperative pain and how serious the pain will be. It is, then, crucial that surgeons are keenly aware of the likelihood of rebound pain occurring in any case where regional anesthesia is administered, that patients are given as realistic of a picture of the pain level they may experience postoperatively as is possible, and that both preventative and rescue methods are used to reduce the overall pain experienced by the patient while minimizing the risk of opioid dependency.
References
(1) Questions About Nerve Blocks | Regional Anesthesia | Stanford Medicine. https://med.stanford.edu/ra-apm/for-patients/nerve-block-questions.html.
(2) Muñoz-Leyva, F.; Cubillos, J.; Chin, K. J. Managing Rebound Pain after Regional Anesthesia. Korean J Anesthesiol 2020, 73 (5), 372–383. https://doi.org/10.4097/kja.20436.
(3) Opioid Crisis | HRSA. https://www.hrsa.gov/opioids.
(4) Dada, O.; Gonzalez Zacarias, A.; Ongaigui, C.; Echeverria-Villalobos, M.; Kushelev, M.; Bergese, S. D.; Moran, K. Does Rebound Pain after Peripheral Nerve Block for Orthopedic Surgery Impact Postoperative Analgesia and Opioid Consumption? A Narrative Review. IJERPH 2019, 16 (18), 3257. https://doi.org/10.3390/ijerph16183257.
(5) Barry, G. S.; Bailey, J. G.; Sardinha, J.; Brousseau, P.; Uppal, V. Factors Associated with Rebound Pain after Peripheral Nerve Block for Ambulatory Surgery. British Journal of Anaesthesia 2021, 126 (4), 862–871. https://doi.org/10.1016/j.bja.2020.10.035.