Postoperative continuous transversus abdominis plane block vs continuous wound infusion of levobupivacaine in females undergoing open gynecologic procedures

Introduction
Transversus abdominis plane (TAP) block is used as a part of multimodal analgesia in decreasing pain of lower abdominal wall incision. Local anesthetic instillation of wounds through subcutaneous or subfascial catheters is used to treat postoperative pain in different types of surgery. The aim of this randomized controlled trial was to study the opioid-sparing effect of these two techniques (if any) compared to placebo in women undergoing gynecologic procedures through transverse lower abdominal incisions.
Methods
Seventy-eight ASA I–III patients planned to undergo gynecologic procedures through a transverse lower abdominal incision were randomly divided into three equal groups: Control (C) group ( = 26), Continuous Wound Infusion (CWI) group ( = 26), and continuous transversus abdominis plane block (TAP) group ( = 26). After standardized general anesthetic and before extubation, the patients were given the allocated treatment. A morphine patient-controlled analgesia (PCA) was started postoperatively alongside with the local anesthetic (or placebo) infusion. Cumulative dose of morphine PCA in the first postoperative 48 h was the primary outcome. Secondary outcomes included visual analog pain score (VAS) at rest and on movement and complications of morphine PCA.
Results
The cumulative dose of morphine PCA in the first postoperative 48 h was higher in control group than in groups CWI and TAP ( < 0.001). However, no significant difference was found between groups CWI and TAP. No significant differences were found among the three groups regarding VAS during rest but TAP group showed less pain scores than groups C and CWI on movement. The three groups were similar regarding morphine side effects.
Conclusion
Continuous bilateral TAP block and CWI can decrease PCA morphine consumption in the first postoperative 48 h when compared to placebo in women undergoing gynecologic surgery through transverse lower abdominal incision. Continuous TAB block might give better analgesia with movement than CWI.