Neuropathic symptoms following continuous popliteal block after foot and ankle surgery

Continuous perineural blocks are increasingly popular for postoperative pain control. While the reported incidence of neuropathic symptoms has been low, the experience of the lead author suggested it may be much higher. The objectives of this study were to elucidate the incidence of patient-reported neuropathic symptoms following continuous popliteal block (CPB) for postoperative pain control in patients undergoing foot and ankle surgery, to characterize these symptoms and to identify preoperative risk factors.

A prospective cohort study of 147 surgical patients undergoing significant foot and ankle procedures was carried out. Patients were followed for 8 months post-surgery. Preoperative/perioperative questionnaires were completed by anesthesiologists. Patients completed questionnaires at 2, 6, 14, and 34 weeks. Multivariable logistic regression analysis using Generalized Estimating Equations (GEE) was used to examine risk factors for neuropathy.

The prevalence of neuropathic symptoms at 2 weeks was 41% (95% CI, 33% to 49%) decreasing to 24% (95% CI, 15.4% to 32.5%) at 34 weeks. Multivariable analyses revealed that tourniquet placement, tourniquet time, use of prophylactic antibiotics, type of anesthesia, level of training in anesthesiology, patient history of chronic pain and patient age were not significantly associated with neuropathy. Smokers were more likely to report neuropathic symptoms (adjusted OR, 2.25; 95% CI, 0.96 to 5.33).

The incidence of neuropathic symptoms may be much higher than previously reported. Smoking may be a risk factor for the development of neuropathic symptoms.