Globally, there are 1 million amputations every year [1]. Lower limb amputations are the most common, with the majority being caused by vascular disease [1]. There are a number of perioperative considerations for anesthesia and analgesia when treating patients undergoing amputation [1].

Pre-operative optimization is essential for controlling acute post-operative pain and to decrease the risk of chronic pain development [1]. A thorough pre-operative evaluation is needed to assess any comorbid conditions [1]. Multiple predictors of poor outcomes have been reported, including coronary artery disease, diabetes mellitus, and end-stage renal disease [6]. Patients with a complex history of chronic pain disorders and those requiring a high baseline daily opioid dosage (> 80 mg) should be further evaluated with a pain specialist approximately 4 weeks prior to amputation [1]. The goal is to optimize the patient’s pain regimen pre-operatively by maximizing non-opioid therapies and reducing daily opioid consumption if possible [1]. This is attempted to improve response to opioid therapy in the immediate post-operative period [1].

During surgery, general anesthesia traditionally has been the preferred modality of anesthesia for amputations [2]. However, the use of regional nerve blocks has recently gained popularity [2]. Regional anesthesia, such as neuraxial or peripheral nerve blocks, is thought to be associated with several advantages when compared with general anesthesia [2]. These include attenuation of the normal physiologic response to stress with lower levels of circulating catecholamines and cortisol, sympathetic blockade with resulting peripheral vasodilation and increased blood flow, decreased hypercoagulability, and the ability to avoid endotracheal intubation and mechanical ventilation [2].

Despite the growing interest in regional anesthesia for amputations, its use remains an area of ongoing research [2]. In a 2013 retrospective analysis of above-knee amputations (AKA) and below-knee amputations (BKA) at the Maimonides Medical Center between 2005 and 2009, the results indicated no mortality benefit of using regional nerve blocks over general anesthesia [2]. A 2019 study looking at 342 patients undergoing lower extremity amputations came to similar conclusions [3]. There was no significant difference in 30-day or 90-day mortality between patients who received regional anesthesia and those who received general anesthesia [3].

Pain management must be considered for an extended period after the surgical amputation because recovery from an amputation takes significant time [1]. Wound healing is typically completed in 4 to 8 weeks, but phantom limb pain (PLP) can prolong the recovery process [1]. PLP develops due to the complex interplay of peripheral and central sensitization [5]. As much as 85% of patients experience PLP, and this chronic pain can last from weeks to years after surgery [1,4].

Early interventions can help to lessen long-term pain for patients [1]. In the management of PLP, gabapentanoids, peripheral nerve catheters, and psychological therapy have been shown to play a therapeutic role [5]. Optimized epidural analgesia starting 48 hours and continuing for 48 hours postoperatively has also been associated with reduced persistent pain at 6 months [5]. The use of adjuvants such as calcitonin or ketamine in epidural analgesia also shows encouraging results, reducing PLP at 1 year [5].

References

1. Seering, M., & Punia, S. (2020). Amputation Pain Management. In Pain Management-Practices, Novel Therapies and Bioactives. IntechOpen. doi:10.5772/intechopen.93846
2. Lin, R., Hingorani, A., Marks, N. et al. (2013). Effects of anesthesia versus regional nerve block on major leg amputation mortality rate. Vascular, 21(2), 83-86. doi:10.1177/1708538113478718
3. Kim, S., Kim, N., Kim, E. et al. (2019). Use of regional anesthesia for lower extremity amputation may reduce the need for perioperative vasopressors: a propensity score-matched observational study. Therapeutics and Clinical Risk Management, 15, 1163. doi:10.2147/TCRM.S213443
4. Kent, M., Hsia, H., Van de Ven, T., & Buchheit, T. (2017). Perioperative pain management strategies for amputation: a topical review. Pain Medicine, 18(3), 504-519. doi:10.1093/pm/pnw110
5. Ahuja, V., Thapa, D., & Ghai, B. (2018). Strategies for prevention of lower limb post-amputation pain: A clinical narrative review. Journal of Anesthesiology, Clinical Pharmacology, 34(4), 439. doi:10.4103/joacp.JOACP_126_17
6. Moreira, C., Farber, A., Kalish, J. et al. (2016). The effect of anesthesia type on major lower extremity amputation in functionally impaired elderly patients. Journal of Vascular Surgery, 63(3), 696-701. doi:10.1016/j.jvs.2015.09.050