Anaesthetic Technique for Minor Lower Limb Amputation Surgery (ATLLAS)

Major lower limb amputation is recognised as a significant cause of morbidity and mortality. In the United Kingdom, 30-day in-hospital mortality is up to 8.7%. Minor lower limb amputations, defined as amputation at or below the ankle, are often considered minor procedures, but mortality at one month is 3.5%, similar to that of below knee amputations and 20% at one year. Any amputation is an indicator of poor health and should be considered a pivotal event in a patient's healthcare journey. In England alone, 21,738 minor lower limb amputations were performed between 2017 and 2020, with annual procedures on an increasing trajectory. Recent work has demonstrated striking regional differences in rates of major lower limb amputations in England which the authors ascribed to inequalities in the provision of healthcare. Improving the regional provision of support services for amputees is also part of the current governments NHS Long Term Workforce Plan (https://lordslibrary.parliament.uk/access-to-prosthetics-for-amputees-in-england/).

While multiple studies have aimed to assess the impact of anaesthetic technique on outcomes following major lower limb amputation, there is little published data on factors impacting morbidity and mortality following minor lower limb amputation surgery. Evidence from the USA has shown deleterious effect of general anaesthesia (GA) as compared to regional anaesthesia for minor lower limb amputation in patients with peripheral artery disease. Higher rates of post-operative wound disruption, pneumonia, prolonged intubation, and septic shock were demonstrated with general anaesthesia rather than regional anaesthesia.

Investigators have performed a single centre retrospective review of 382 patients undergoing minor lower limb amputation for vascular disease in our Trust (UHNM). We found that our patients undergoing these procedures under peripheral nerve block (PNB) techniques were older with higher rates of heart and kidney disease than those receiving a general anaesthetic. Despite this, these patients had reduced complications and length of hospital stay than the fitter patients. The difference seen here became even more pronounced following propensity matching. Investigators demonstrated a clinically significant reduction in the respiratory complication rate of 5.3% and overall complication rate of 12% and a reduction in length of stay of 6 days following use of peripheral nerve blocks rather than general anaesthesia. Investigators also demonstrated a reduction in length of stay of 4 days when DARF Form v4 - July 2023 16 administering peripheral nerve blocks rather than neuraxial anaesthesia (NA). This small and monocentric study suggests that there is value in repeating this process in a larger, national dataset.