Analgesic Effect of Double-Level Retrolaminar Paravertebral Block for Breast Cancer Surgery in the Early Postoperative Period: A Placebo-Controlled, Randomized Clinical Trial.

Thoracic epidural anesthesia (TEA) and paravertebral block (PVB) have been performed for perioperative regional anesthesia in the trunk. However, TEA and PVB are associated with a risk of serious complications, such as pneumothorax, hypotension, or nerve damage. Retrolaminar paravertebral block (RLB) was introduced as a new alternative to PVB. This new approach might lower the risk of serious complications, but its use has not been well established yet. Therefore, we conducted a double-masked, placebo-controlled, randomized clinical trial to evaluate the efficacy of a double-level RLB for postoperative analgesia after breast cancer surgery. A total of 122 women who underwent breast cancer surgery with axillary lymph node dissection under general anesthesia were allocated into RLB group (60 patients) and Control group (62 patients). RLB was performed upon surgery completion with 15 ml ropivacaine (0.5%) for each lamina of the T2 and T4 vertebrae. In Control group, the same volume of normal saline was injected at each level. The time to first postoperative analgesic administration was significantly longer in RLB group than that in Control group (161.5 min vs. 64.0 min). The pain score in RLB group was significantly lower immediately after surgery. However, the number of patients requiring analgesics during the 12-hour post-surgical period was similar between RLB group (20 patients) and Control group (22 patients). In conclusion, the double-level RLB could delay the time to initial administration of analgesics, but this technique may be insufficient to reduce the analgesic requirement within the 12-hour postoperative period following breast cancer surgery.