A randomised clinical trial comparing pre-incision ‘single-shot’ nerve block and continuous peri-neural catheter for patients undergoing a major lower limb amputation.

Major lower limb amputation, (MLLA) are commonly performed operations by Vascular Surgeons; over 3000 each year. At present there lacks a universally accepted method of pain relief for these patients. Phantom limb pain is a recognised common problem; the best way to achieve good pain relief is to use a variety of methods but practice and experience is variable. One method is to inject the nerve’s coating (perineural sheath) with a local anaesthetic before surgery has started (single shot nerve block) another is to place a catheter into this sheath (perineural catheter or PNC) to deliver a continuous infusion of local anaesthetic for up to 7 days post operatively.

This study will compare these two methods to find out which results in less post-operative pain for our patients. Other outcomes which will be compared include the length of operations and anaesthetic time, patient’s daily pain scores, painkiller use, length of stay in hospital, patients’ scores for phantom limb pain, engagement and progress with the physiotherapists.

Eligible patients are anyone undergoing a primary above/below knee amputation under general anaesthetic for the symptoms resulting from peripheral vascular disease, aged over 18 years old. They need to be able to consent to amputation and study participation and to participate in assessing their pain using pain scores and assessment questionnaires.

The study will be conducted at a single major tertiary vascular centre. The participants will be involved in the study for 6 weeks. They will fill out daily pain scores for the first week, phantom limb score and two quality of life questionnaires pre-op and at day 7 and at their usual 6 week outpatient clinic follow up. Physiotherapists will document daily progress for the first week. We intend to gain funding to review these patients at a year to detect difference in long-term phantom pain.