Comparative randomized study of continuous serratus anterior plane block versus continuous paravertebral block in post-mastectomy pain

Background
Many analgesic methods have been used to control post-mastectomy pain. Both thoracic paravertebral and serratus anterior blocks are recent regional techniques with promising results. The aim of this study was to compare safety and analgesic efficacy of both techniques in controlling post-mastectomy pain.
Methods
The study was conducted from January 1, 2019, till January 10, 2019, on 60 female patients ASA class ≤ 2 undergoing modified radical mastectomy. After induction of balanced general anesthesia patients received either continuous thoracic paravertebral block (group P) or continuous serratus anterior block (group S). Twenty milliliters of levobupivacaine 0.25% were injected in each technique under ultrasound guidance followed by continuous infusion of 5 ml/h levobupivacaine 0.125% through a 22-gage catheter. IV morphine was given postoperatively by patient-controlled analgesia. In both groups, we measured time to first dose morphine, total 24 and 48 h morphine consumption, vital signs, visual analog scale, and side effects of each technique.
Results
The demographic data (age, body mass index, and duration of surgery) were comparable in both groups. The time for first dose of morphine was significantly longer in group P (368 ± 36 min) than group S (270 ± 37.65 min) with value < 0.001. Total morphine consumption in milligram at both 24 and 48 h were significantly less in group P (8.1 ± 0.8, and 11.5 ± 1 respectively) than in group S (10.1 ± 1.3 and 14.2 ± 1.4), with limited side effects in both groups.
Conclusion
Both continuous paravertebral and serratus anterior plane blocks are safe good alternatives to control post-mastectomy pain. However continuous paravertebral block provides better analgesic profile.