Efficacy of serratus anterior muscle block as a part of multimodal analgesic regimen in patients undergoing modified radical mastectomy

Background: The quest for optimal analgesia after modified radical mastectomy has made anaesthesiologist steer its way into the arena of ultrasound guided interfascial blocks. Providing round the clock post operative analgesia is standard care of treatment provided in our institution to enhance early recovery and prevent morbidity secondary to chronic pain syndromes.  We hypothesised that administering serratus anterior muscle (SAM) block as a part of multimodal analgesia would be more efficacious in providing post-operative pain relief than intravenous patient-controlled analgesia (IV- PCA) alone in patients undergoing modified radical mastectomy (MRM).

Methods: After obtaining the institutional ethics committee approval  and written informed consent, 60 females with American  Society of Anaesthesiolgy (ASA) physical status I and II, aged between 20-80 years, scheduled to undergo MRM under general anaesthesia were randomized to receive post-operative IV-PCA with or without ipsilateral SAM block administered in the study group just after induction. The data was analysed for all quantitative variables and  measures of dispersion. Normality of data was ascertained and appropriate  statistical tests were applied.

Results: The mean pulse, blood pressure and VAS (at rest and movement) was found to be significantly higher at all time intervals in the group not receiving SAM block. Also, the total morphine dose, rescue analgesic consumption as well incidence of post operative nausea and vomiting was higher in group that received IV-PCA only in the post operative period.

Conclusions: We conclude that post induction, single shot ultrasound guided ipsilateral serratus anterior muscle block provides effective post operative analgesia in patients undergoing modified radical mastectomy than IV-PCA alone.