Multi-injection paravertebral block with low volume local anesthetic for anesthesia in radical mastectomy – randomized controlled trial

Introduction
Paravertebral block (PVB) is generally used in breast cancer surgery in combination with general anesthesia. Only multi-injection PVB can decrease the volume of local anesthetic (LA) while maintaining the efficacy of the block. The use of small LA volumes in PVB prevents its undesirable distribution from the injection site. The objective of this study was to examine the effect of multi-injection paravertebral block for anesthesia in radical mastectomy in breast cancer patients.

Material and methods
The study analyzed 130 cases of anesthesia in radical mastectomy. The patients were randomized to two groups: Group 1 (n = 65) received general anesthesia (GA), and Group 2 (n = 65) received PVB (Th1 to Th6) with GA. In Group 2, 0.75% ropivacaine solution at 1.5 to 3.0 mL per level was used. Serum cortisol levels were measured. The post-operative acute pain perception was measured using a 100-point visual analogue scale (VAS).

Results
Fentanyl consumption in Group 1 was 70% higher than in Group 2 (P < 0.05). No increase in intra-operative cortisol levels was seen; 2 hours after surgery, cortisol levels were 3.3 times and 2.7 times higher than the baseline in Group 1 and Group 2, respectively (P < 0.05). VAS scores in Group 2 were lower at 2, 6, 12, and 48 hours after surgery (P < 0.05).

Conclusions
Supplementation of GA with multilevel PVB decreased the intra-operative fentanyl consumption. In radical mastectomy, the intra-operative cortisol levels do not increase. The highest VAS pain scores are seen within the first 24 hours after mastectomy.