ESRA19-0346 Specific block of the plantar branches of the tibial nerve for foot surgery: a monocentric pilot study

Background and aims Sciatic nerve block (SNB) is the standard for foot surgery, providing good anaesthesia and long duration of analgesia. However, the proximal sciatic block results in a motor blockage of the ankle, making walking impossible in the early postoperative period. This study was designed to assess the feasibility of a specific block of the tibial nerve plantar branches (TNPB, figure 1). Methods After approval of the Ethics Committee and written informed consent, 25 patients admitted for foot surgery were enrolled in this prospective study. Each block was performed under ultrasound with 5 ml of 0.375% Ropivacaine including block of medial and lateral plantar branches and block of peroneal nerves. Block efficiency was assessed by pinprick and cold tests in the sensory territory of each nerve. Results Demographic data are presented in table 1. Forty minutes after TNPB, surgical anaesthesia was obtained in 100% of patients for medial plantar nerve area and 12% for lateral area. Additional anaesthesia was required in 8 patients (5 SNB, 3 general anaesthesia). Five patients requested sedation for comfort. In the postoperative period, heel sensibility was preserved in 95% of patients. Conclusions A specific block of TNPB is possible at the medial edge of the foot. It makes it possible to respect the calcaneal branch, thus maintaining the sensitivity of the heel. While the medial branch block is systematic, efficiency on the lateral branch is inconstant. a more proximal approach or the use of a larger volume of anaesthetic should be considered.