Thoracic paravertebral block versus transversus abdominis plane block in major gynecological surgery: a prospective, randomized, controlled, observer-blinded study

BACKGROUND AND OBJECTIVES Patients undergoing abdominal surgery often receive an epidural infusion for postoperative analgesia. However, when epidural analgesia is contraindicated or unwanted, the administration of opioids is the usual means used to relieve pain. Various regional analgesia techniques used in conjunction with systemic analgesia have been reported to reduce the cumulative postoperative opioid consumption and opioid-induced side effects. The objective of this trial was to assess the effectiveness of transversus abdominis plane block and paravertebral block in women undergoing major gynecological surgery. METHODS We analyzed 58 patients scheduled for a midline vertical laparatomy due to gynecological cancer. They were all equipped with a patient-controlled postoperative analgesia pump that delivered ketobemidon. In addition, some patients were randomized to receive either a bilateral transversus abdominis plane block (n = 19) or a bilateral paravertebral block at the level of Th10 (n = 19). Both blocks were performed preoperatively as a single injection of bupivacaine. RESULTS Cumulative ketobemidon consumption, postoperative pain scores at rest and while coughing, and postoperative nausea and vomiting scores were assessed by a blinded observer at 2, 4, 6, 24, and 48 hours postoperatively. Both blocks were associated with significant reductions in opioid consumption and pain scores throughout the study period compared with the control patients. Postoperative nausea and vomiting scores were low in all groups, but during the early postoperative period more control group patients needed antiemetics. CONCLUSION Both methods of inducing block can serve as effective analgesia adjuncts in women undergoing major gynecological surgery. Although thoracic paravertebral block appeared to be more effective than transversus abdomins block, the latter performed under ultrasound guidance seems to be a more controlled and safe alternative.