A comparative randomized study of paravertebral block versus wound infiltration of bupivacaine in modified radical mastectomy.

Background: Paravertebral block (PVB) has the potential to offer long-lasting pain relief because it can uniquely eliminate cortical responses to thoracic dermatomal stimulation. Benefits include a reduction in postoperative nausea and vomiting (PONV), prolonged postoperative pain relief, and potential for ambulatory discharge.

Aims: To compare PVB with local infiltration for postoperative analgesia following modified radical mastectomy (MRM).

Methods: Forty patients undergoing MRM with axillary dissection were randomly allocated into two groups. Following induction of general anesthesia in group P, a catheter was inserted in the paravertebral space and 0.3 ml/kg of 0.25 % of bupivacaine was administered followed by continuous infusion, while in group L, the surgical incision was infiltrated with 0.3 ml/kg of 0.25 % bupivacaine.

Statistical Analysis: The statistical tests were applied as unpaired student 't' test/nonparametric test Wilcoxon Mann Whitney test for comparing different parameters such as VAS score and consumption of drugs. The categorical variables such as nausea and vomiting scores, sedation score, and patient satisfaction score were computed by Chi square test/Fisher exact test.

Results: VAS score was significantly lower in group P than in group L throughout the postoperative period. The mean alertness score (i.e., less sedation) was higher in group P in the postoperative period than group L. The incidence of PONV was less in PVB group.

Conclusion: PVB at the end of the surgery results in better postoperative analgesia, lesser incidence of PONV, and better alertness score.