[Triple nerve block for ambulatory knee arthroscopy]

Background: The purpose of this study was to evaluate intra- and postoperative conditions of the triple nerve block technique (femoral, obturator, sciatic block) for outpatient knee arthroscopic procedures.

Methods: After written informed consent, ASA I-III patients received a combined triple nerve block with 30-40 ml lidocaine or mepivacaine (1,5%). Blocks were performed using a nerve stimulation technique. Onset time, block failure, supplemental general anesthesia (GA) or analgesia and pain score were recorded intraoperatively. After surgery, side effects (at days 0, 1, 3, 7 and after 4 weeks), patient and surgeon satisfactions were noted.

Results: Three hundred and twelve patients were screened and 115 triple blocks were performed (157 chose GA, 19 spinal anaesthesia, 21 exclusion for regional anaesthesia). Failed blocks occurred for 12 (10%) patients. These 12 patients received GA before surgery incision. Time to complete block was 40 (10-60) min. Supplemental GA was required for 12 patients (12%) due to surgical (n=7, 7%) or tourniquet (n=5, 5%) pain. Intraoperative surgeon satisfaction was 90 (60-100). After surgery, time to discharge the postoperative care unit was 15 (5-60) min. Pain score at rest (Visual Analog Scale) until six hours was less than 30 /100, without any additional morphine. Two patients (< 2%) failed for ambulatory discharge criteria (no relation with triple block). At day 0, 3, 5% patients suffered PONV (8% at D1), paresthesia was noted in 1.7% at D0 (0,8% D3). No other secondary effects were observed after seven days and 91% patients "would like same anaesthesia" for next surgery.

Conclusion: We conclude that triple nerve block provided reliable intraoperative patient and surgical conditions for outpatient knee arthroscopy. Failed block (10%) was the major reason of supplemental anaesthesia. To increase surgical turn over under triple nerve block, a preoperative room may be required (block onset time).