Background: Paravertebral block (PVB) is widely used analgesia technique for breast surgery. Pectoral nerve block (PECS) is a novel interfascial plane block which can provide analgesia for this purpose. We evaluated the difference between the two techniques in regard to analgesic efficacy after modified radical mastectomy (MRM)

Methods: Sixty patients (n=60) undergoing elective MRM are randomly allocated into either PVB group (n=30) (20 ml of 0.5% ropivacaine at the level of fourth thoracic vertebra) or PECS Group (n=30) (10 ml of 0.5% ropivacaine injected in between pectoralis major and pectoralis minor muscle and another 20 ml 0.5% ropivacaine in between pectoralis minor and serratus anterior muscle). Primary outcome measure was post-operative pain scores in the first 24 hours. Secondary outcome measures include tramadol consumption, intraoperative fentanyl consumption and postoperative nausea and vomiting.

Results: The post-operative pain scores were lower in Pecs group compared with PVB for the first 12 hours (p =0.002). There was no significant difference after that. The time for first request for analgesia is significantly longer in Pecs block compared to PVB (p< 0.001). There is no difference in the post-operative tramadol consumption. The incidence of nausea and vomiting was comparable between both groups.

Conclusion: PECS is as efficacious as PVB for post operative analgesia after MRM. Modified pectoral block is easier to perform and is an excellent alternative to PVB