Effect of adding dexmedetomidine as an adjuvant to bupivacaine in ultrasound-guided erector spinae plane block for postoperative pain management following modified radical mastectomy: a randomized controlled trial

Postoperative pain after modified radical mastectomy (MRM) can lead to significant morbidity. The erector spinae plane block (ESPB) has emerged as an effective regional anesthesia technique. This study evaluated the effect of adding dexmedetomidine to bupivacaine on postoperative analgesia following ESPB in MRM. This double-blinded, randomized controlled trial included 60 female patients (ASA I–II, age 30–65 years, BMI < 35 kg/m²) undergoing MRM at Ain Shams University Hospitals between August 2023 and July 2024. Patients were randomly allocated into two groups (n = 30 each): Group B received unilateral ESPB with 20 ml of 0.5% bupivacaine, and Group BD received 10 ml of 0.5% bupivacaine plus dexmedetomidine (100 µg/mL, 1 µg/kg) diluted to a total volume of 20 ml with 0.9% saline. Blocks were performed postoperatively in lateral decubitus position under ultrasound guidance. Rescue analgesia consisted of IV nalbuphine 5 mg for VAS > 4. The median (IQR) time for request of the initial dose rescue analgesia was significantly delayed in group BD compared to group B [690 (525–795) versus 360 (300–420), respectively, P-value < 0.001]. The number of patients that required nalbuphine was significantly lower in group BD compared to group B (P-value = 0.004). The median (IQR) visual analogue scale (VAS) scores at 6 h postoperative were significantly reduced in group BD compared to group B [1 (1–2) versus 4 (4–4), P-value < 0.001]. Our study’s results indicated that adding dexmedetomidine to bupivacaine in ESPB enhanced its efficacy, extended postoperative pain relief, and reduced the need for nalbuphine. The identification code in the clinicaltrials.gov database is NCT06022614, registration date: 1 September 2023, and it is also listed in the Pan African Clinical Trials Registry with the ID PACTR202307885435649, registration date: 27 July 2023. The research adhered to the CONSORT 20205 framework. Randomized controlled trial registered on 1 September 2023.