Objective To compare motor blockade between local anaesthetic inFiLtration Around Genicular Structures (FLAGS) and sciatic nerve block (caudal approach) (SCIATIC) in dogs undergoing stifle surgery. Randomized, prospective, open-label clinical trial. Twenty-eight dogs with cranial cruciate ligament disease. Dogs were randomly allocated to SCIATIC or FLAGS group. Under general anaesthesia, both groups received a saphenous nerve block. An ultrasound-guided sciatic nerve block (caudal approach) and a FLAGS block were performed in the SCIATIC and FLAGS groups, respectively. The FLAGS block was performed at the level of the femoral condyles, with the needle inserted in-plane from lateral to medial until the tip was positioned cranial to the popliteal artery, between the condyles. For all blocks, 0.1 ml kg -1 of bupivacaine 0.5% was injected at each site. Intraoperative rescue analgesia was provided if heart rate (HR), respiratory rate ( f R ) or mean arterial blood pressure (MAP) increased more than 20% from baseline values (before skin incision) for more than 2 minutes during surgery. Two hours after surgery, motor function was assessed by evaluating patellar, sciatic, gastrocnemius, cranial tibial, and withdrawal reflexes, each scored 0–2, with lower combined scores indicating better motor function. Data were analysed using Shapiro–Wilk tests, followed by Student’s t tests or Mann–Whitney U tests. Fisher’s exact test used for categorical variables. Fifteen dogs were allocated to the SCIATIC group and 13 to the FLAGS group, respectively. No animals required rescue analgesia. The FLAGS group had significantly lower postoperative total motor score when compared to SCIATIC group scores SCIATIC, 3 (0–8), FLAGS, 0 (0–5); p = 0.032. The FLAGS block was associated with less motor function impairment at the 2 hour postoperative assessment compared with the sciatic nerve block in dogs undergoing stifle surgery.
García-Urdiales et al. (Wed,) studied this question.