Perioperative ketamine for preventing phantom limb pain after amputation in patients with limb ischemia: A pilot study

Tóm tắt

Phantom pain after limb amputation (PLP) remains a challenge to prevent and manage due to its complex mechanism involving peripheral, neural, central and psychogenic mechanisms. In patients with limb ischemia who have frequent long history of ischemic pain and opioid consumption, the incidence of PLP seems to be soaring and more severe. Although advances in the management and treatment of vascular diseases have reduced the need for amputation in this population, managing postoperative pain remains a significant challenge and necessitates effective preventive strategies. Ketamine, which is not only an anesthetic but also a potential medication for the treatment of chronic pain, neuropathic pain, and phantom pain, is anticipated to prevent PLP. This is a prospective study conducted on six patients (63 - 77 years old) with limb ischemia undergoing amputation surgery. The results showed that PLP occurred in 3 patients (50%), with the average visual analog score (VAS) of 1 (range of 0-7 on day 3, 0-4 on day 5). Phantom sensation was also recorded early in 3 patients (50%) and two of these 3 patients developed phantom pain later, suggesting that patients with postoperative phantom sensation should be observed thoroughly. Stump pain after amputation gradually decreased from day 1 (median 2.5, range 0-7) to 2.5 (range 0-4, day 2) and 2 on day 5 (range 0-3) without morphine rescue. Intraoperative ketamine infusion in this study has demonstrated its effectiveness in reducing PLP severity and postoperative stump pain without side effects. However, longer follow-up with a larger dataset is needed to further evaluate the long-term effects of ketamine on PLP.