Dexmedetomidine and transversus abdominis plane block in multimodal general anesthesia for postoperative patient-controlled analgesia after uterine surgery: a propensity-score-matched cohort study

BACKGROUND: Multimodal general anesthesia (MGA) combines hypnotic adjuvants and regional analgesia, but their individual contributions to postoperative patient-controlled analgesia (PCA) remain unclear. This study evaluated the effects of dexmedetomidine and transversus abdominis plane (TAP) block on PCA-derived analgesic outcomes after uterine surgery. METHODS: This single-center retrospective propensity-score-matched study included adult women undergoing elective hysterectomy or myomectomy with morphine-based intravenous PCA between 2021 and 2024. Patients were matched 1:1:1 into three groups: MGA with dexmedetomidine plus TAP block, TAP block without dexmedetomidine, and conventional balanced general anesthesia alone. The primary outcome was the 48-h PCA demand/delivery ratio. Secondary outcomes included morphine consumption, pain scores, PCA-related adverse events, and prescription re-adjustment. RESULTS: After matching, 192 patients were analyzed, with 64 patients in each group. The MGA group had the lowest 48-h demand/delivery ratio compared with the TAP-block and control groups (1.00 [1.00-1.13] vs. 1.06 [1.00-1.35] and 1.09 [1.00-1.40], respectively; p = 0.013). Both TAP-containing groups consumed less morphine than controls, whereas morphine consumption did not differ between MGA and TAP block alone. The MGA group had lower intraoperative fentanyl requirement and postoperative-day-1 dynamic pain than controls; neither differed significantly between MGA and TAP-block groups. PCA-related adverse events and re-adjustment rates were comparable among groups. CONCLUSION: In women receiving morphine PCA after uterine surgery, TAP block was the component most consistently associated with postoperative morphine sparing, whereas dexmedetomidine-containing MGA was associated with a lower PCA demand/delivery ratio without increased adverse events.