Background: We aimed to assess whether an ultrasound (US)-guided oblique subcostal transversus abdominis plane (OSTAP) block would improve the postoperative pain scores and decrease the tramadol consumption after a laparoscopic hysterectomy.
Methods: Sixty-six female patients with American Society of Anesthesiologists I, II, or III, aged 18 to 65 years who were scheduled for laparoscopic hysterectomy for benign gynecologic pathologies were recruited in this randomized, controlled, observer-blinded trial. Sixty patients completed the study. Patients were randomized into 2 groups. In the OSTAP group, the patients received a bilateral OSTAP block with 40 mL of 0.375% bupivacaine and in the Sham group received an US-guided bilateral OSTAP with 40 mL of 0.9% saline. All patients received tramadol patient-controlled analgesia for the first 24th hour. Patients in the Sham group received an US-guided bilateral OSTAP with 40 mL of 0.9% saline. The primary outcome was the 24th hour tramadol consumption. The secondary outcomes included visual analog scale (VAS) scores during movement, the tramadol consumption at the 1st, 4th, and 12th postoperative hours, and nausea scores at the 24th hour postoperatively.
Results: At all time points, tramadol consumption of the OSTAP group remained significantly lower when compared with Sham group. The OSTAP group showed a statistically significant reduction at the postoperative 24th hour tramadol consumption (mean difference 22 mg, 95% confidence interval -38.4 to -5.6 mL; P = .009). Compared with the Sham group, OSTAP block reduced the VAS scores at all time points during movement. Nausea scores at the 24th postoperative hour were significantly lower in the OSTAP group compared with the Sham group CONCLUSION:: We concluded that bilateral US-guided OSTAP blocks reduced 24th hour tramadol requirements and VAS scores after laparoscopic hysterectomy. The OSTAP block is a promising technique for producing effective and prolonged postoperative analgesia in patients undergoing laparoscopic hysterectomy surgeries.