Comparison between ultrasound-guided sciatic-femoral nerve block and unilateral spinal anaesthesia for outpatient knee arthroscopy.

OBJECTIVE: To compare unilateral spinal anaesthesia (USA) and ultrasound-guided combined sciatic-femoral nerve block (USFB) in ambulatory arthroscopic knee surgeries in terms of haemodynamic stability, nerve block quality, bladder function, adverse events and time-to-readiness for discharge (TRD). METHODS: Patients undergoing ambulatory arthroscopic knee surgery were randomly assigned to one of two groups. The USA group received 2 ml (10 mg) of 0.5% levobupivacaine and the USFB group received a 25 ml mixture consisting of 10 ml of 2.0% lidocaine, 10 ml of 0.5% levobupivacaine and 5 ml of saline (15 ml for the femoral and 10 ml for the sciatic nerve block). Preparation time (PT), surgical anaesthesia time (SAT), operation time, total anaesthesia time, time-to-first spontaneous urination, time-to-first analgesia, TRD, adverse events and patient satisfaction were recorded. RESULTS: A total of 40 patients were enrolled in the study (n = 20 per group). PT, SAT, total anaesthesia time and time-to-first analgesia were significantly shorter in the USA group than the USFB group; time-to-first spontaneous urination and TRD were significantly longer in the USA group than the USFB group. CONCLUSIONS: USFB provided sufficient duration of sensory blockade and it reduced the TRD and the rate of adverse events.