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

Abstract

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). 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. 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. USFB provided sufficient duration of sensory blockade and it reduced the TRD and the rate of adverse events.