Design: Randomised controlled feasibility trial.
Setting: Two Vascular Centres in South Wales, UK.
Participants: 50 patients scheduled for major lower limb amputation (below or above knee) for complications of peripheral vascular disease.
Interventions: The treatment arm received a PNC placed adjacent to the sciatic or tibial
nerve at the time of surgery, with continuous infusion of Levobupivacaine hydrochloride 0.125% for up to 5 days. The control arm received neither local anaesthetic nor PNC. Both arms received usual peri-operative anaesthesia and post-operative analgesia.
Primary and secondary outcome measures: The primary outcomes were the proportion of eligible patients who were randomised and the proportion of recruited patients who provided primary effectiveness outcome data. Secondary outcomes were the proportion of recruited patients reaching 2- and 6-month follow-up and supplying pain data; identification of key cost drivers; development of an economic analysis framework for a future effectiveness trial; identification of barriers to recruitment and site set up and identification of the best way to measure post-operative pain.
Results: Seventy-six of 103 screened patients were deemed eligible over a 10-month period. Fifty (64.5%) of these patients were randomised, with one excluded in the peri-operative period. Forty-five (91.3%) of 49 recruited patients provided enough pain scores on a 4-point verbal rating scale to allow primary effectiveness outcome evaluation. Attrition rates were high; 18 patients supplied data at 6-month follow-up. Costs were dominated by length of hospital stay. Patients and healthcare professionals reported that trial processes were acceptable.
Conclusions: Recruitment of patients into a trial comparing PNC use to usual care after major lower limb amputation with post-operative pain measured on a 4-point verbal rating scale is feasible. Evaluation of longer-term symptoms is difficult.
Trial registration: ISRCTN: 85710690. EudraCT: 2016-003544-37.