The addition of intrathecal morphine to a transversus abdominis plane block with liposome bupivacaine provides more effective analgesia than transversus abdominis plane block with liposome bupivacaine alone: a retrospective study

Objective: The purpose of this study was to determine if the standardization of using liposomal bupivacaine in transversus abdominis plane (LB TAP) blocks eliminated the benefit of intrathecal morphine (ITM) in patients after undergoing a cesarean section. Methods: This was a retrospective review of 358 patients who underwent cesarean section over an 11-month period. Patients were divided into two groups: those who received only an LB TAP (67 patients) vs those who received an LB TAP and ITM (291 patients). All blocks were placed bilaterally under ultrasound guidance after closure of the surgical incision, and morphine was added to the spinal used for the case. Results: The group that received ITM in addition to the LB TAP received less opioids in the first 24 hours (median 5 range 0-150 mg morphine equivalents [ME] vs 15 range 0-76 mg ME; P<0.001) and less opioids overall (35 mg range 0-450 mg ME vs 47.5 mg range 0-189 mg ME; P=0.041) when compared to the LB TAP block only group. There was no difference between the two groups in opioid use from 24 to 48 hours or 48 to 72 hours. Conclusion: Patients who received ITM in addition to an LB TAP block received less opioids in the first 24 hours and overall when compared to those who received an LB TAP alone. This suggests that ITM still plays a role in providing analgesia to patients who have also received an LB TAP block as a part of their multimodal pain regimen for cesarean sections.