Adjuvants to Bupivacaine in Thoracic Paravertebral Block for Prolongation of Postoperative Analgesia After Unilateral Breast Cancer Surgery

Abstract

Background: Breast cancer is the most common malignancy in women, and surgery often results in significant postoperative pain. Thoracic paravertebral block (TPVB) with local anesthetics can provide effective analgesia, and adding suitable adjuvants may further prolong pain relief. The aim of this study was to compare the effectiveness of fentanyl, dexamethasone, and magnesium sulfate as adjuvants to bupivacaine in thoracic paravertebral block for prolonging postoperative analgesia after unilateral breast cancer surgery.

Methods: This randomized controlled trial was conducted at BSMMU on 90 female patients undergoing unilateral breast cancer surgery. Patients were allocated into three groups (n=30): Bupivacaine with fentanyl (100 µg), dexamethasone (10 mg), or magnesium sulfate (80 mg). Ultrasound-guided TPVB was performed at T4, and outcomes included VAS pain score, time to first analgesic, opioid consumption, and complications.

Results: The mean age of patients was comparable among the groups (Group-F: 39.9±6.2, Group-D: 39.7±6.2, Group-M: 39.8±6.2 years). Onset of sensory block was faster in Group-F (8.17±1.14 min) than in Group-D (9.02±1.68 min) and Group-M (8.93±1.52 min), though not statistically significant. Heart rate and systolic blood pressure remained stable across groups, with 13.3% of Group-M experiencing perioperative hypotension. Postoperative pain scores (VAS) were significantly lower in Group-F at 2, 6, and 12 hours compared to Group-D and Group-M. The duration of analgesia was longest in Group-F (447.5 min) versus Group-D (432.6 min) and Group-M (437.8 min), although the difference was not statistically significant. Overall, fentanyl provided superior pain control and prolonged analgesia.

Conclusion: In this study fentanyl is better than dexamethasone and magnesium sulfate but dexamethasone and magnesium sulfate both are also an effective adjuvant for prolongation of postoperative analgesia in thoracic paravertebral block after unilateral breast cancer surgery.