Analgesic Efficacy of Ultrasound-Guided Interscalene Block Versus Supraclavicular Block for Ambulatory Arthroscopic Rotator Cuff Repair: a Prospective, Randomized, Single-blind, Comparative Study

The number of patients undergoing ambulatory arthroscopic rotator cuff repair (ARCR) in our center is increasing annually. This procedure is associated with significant postoperative pain and effective analgesia is required in order to develop day-case surgery. Although continuous interscalene catheter block (ISB) is considered to be the most effective analgesic technique for ARCR, the difficulties in implementing and monitoring ISB have led to many anesthesiologists preferring single injection block, so that patients can be discharged on the same day as surgery with a satisfactory level of pain control.

ISB is frequently associated with phrenic nerve block,even with low volumes of local anesthetics. Phrenic nerve block is a concern in some ambulatory surgery patients as it may lead to respiratory complications after hospital discharge, limiting the eligibility of many patients for day surgery. Changes in spirometry variables have been associated with ISB, whatever the site of injection around the roots (anterior or posterior). Nevertheless, effective regional anesthesia (RA) is essential for this surgery, because multimodal analgesia alone is insufficient.

Several alternatives to ISB exist that are associated with a decreased prevalence of phrenic nerve paresis.6 Supraclavicular block (SCB) decreases the risk of phrenic nerve involvement, particularly when guided by ultrasound. This technique, which has been linked to a risk of pneumothorax when carried out by neurostimulation only, has now been revived and is included among the RA techniques considered to be safe in terms of respiratory risk, especially when guided by ultrasound. Many studies have demonstrated a decreased risk of phrenic paresis with ultrasound-guided SCB, even with volumes as high as 20 mL. Published studies have demonstrated that SCB is an effective alternative to ISB, and many studies have shown that ultrasound-guided SCB is a safe technique for ambulatory shoulder surgery in terms of respiratory complications. SCB is therefore a real alternative to ISB for ambulatory ARCR, but comparative studies are necessary to evaluate its analgesic efficacy after patients have been discharged from hospital, particularly in terms of their oral morphine consumption at home.

Investigators carried out a monocentric, prospective, comparative study to determine whether SCB is non-inferior to ISB in terms of post-operative analgesia in patients undergoing ambulatory ARCR. Analgesic efficacy was determined by oral morphine use and/or pain scores in patients after hospital discharge. Promotor hypothesis was that SCB would provide similar or better analgesia to ISB in patients returning home on the evening of their surgery.