Utility of Peripheral Nerve Block in Lower Extremity Amputation

Approximately 200,000 limb amputations (LA) occur annually in the United States, with almost two million people living with limb loss. Phantom limb pain (PLP) is a common sequela of LA, and accounts for $12 billion in health care expenditure. The optimal anesthetic modality to reduce PLP and improve perioperative outcomes remains unclear. This study evaluated whether peripheral nerve block (PNB), used as a primary anesthetic modality, improves perioperative outcomes compared with general anesthesia (GA) in lower extremity amputation (LEA).

A single-institution retrospective review was conducted of adult patients undergoing first-time LEA between January 2019 and June 2020. Patients were stratified by anesthetic techniques: GA, PNB, neuraxial anesthesia, or GA combined with PNB. Outcomes included incidence of PLP, length of hospital stay, opioid requirements within the first 72 hours, and operative/anesthetic time. Statistical analyses included ANOVA, chi-square testing, and multivariable regression with robust standard errors.

193 records were reviewed; 179 met inclusion criteria. GA was used in 54% of cases, GA+PNB in 44%, and PNB or neuraxial anesthesia in 2%. Patients receiving PNB alone were older and had higher BMI, with a greater proportion undergoing below-knee amputation. PLP incidence was lower in GA compared with GA+PNB (8% vs 14%), though not statistically significant. Notably, no cases of PLP occurred in patients receiving PNB alone. PNB use was associated with lower opioid requirements and a significant reduction in operative time, while hospital length of stay was similar across groups. Phantom limb pain did not differ significantly between groups (GA+PNB vs GA), OR = 1.94, 95% CI [0.71, 5.28], p =0.196.

Overall, PNB demonstrated potential benefits in reducing opioid use and operative time, with promising findings regarding PLP prevention. These results support further prospective, randomized trial of PNB as a primary anesthetic strategy for LEA.