Comparison of Posterior and Subcostal Ultrasound-Guided Transversus Abdominis Plane Block Approaches for Postoperative Analgesia in Laparoscopic Cholecystectomy

Abstract
Background: Pain after LC is complex and characterized by various components with different intensities and time courses. The establishment of LC as an outpatient procedure has accentuated the clinical importance of proper post-operative pain control.
Aim: Our aim is to compare between US posterior and subcostal approaches TAP block for post-operative analgesia in LC.
Material and Methods: This study was carried out on 60 patients, ASA I-II, scheduled for elective laproscopic chole-cystectomy under general anesthesia. Patients were randomized into three equal groups (20 patients in each group): Group I (control group): Received standard general anesthesia. Group
II (posterior TAP group): Received standard general anesthesia and bilateral US guided posterior TAP block with 15ml bupivacaine 0.25% on each side just before extubation. Group
III (subcostal TAP group): Received standard general anesthesia and bilateral US guided subcostal TAP block with 15ml bupivacaine 0.25% on each side just before extubation. All groups received post-operative analgesia in the form of IV paracetamol 1gm every 6 hours and rescue analgesic in form of morphine 2mg IV. The following parameters were compared: Post-operative vital signs (HR & MAP), post-operative pain (using 10 point Visual Analogue Scale (VAS) where (0) no pain and (10) most intense pain), time for first post-operative required analgesia and 24-hour morphine consumption were measured in the 3 groups immediately after full recovery of anesthesia, 1h, 2h, 4h, 6h, 8h, 12hr & 24hr.
Results: In our study the mean values of HR and MAP were lower in Group II and Group III than Group I & that of Group III were lower than that of Group II at all times after recovery. The mean values of pain assessment by VAS in Group II and Group III were lower than that of Group I at all times after recovery. The VAS in Group III were lower than that of Group II insignificantly immediately after recovery, 1h, 2h, 12h and 24 hours and significantly at 4h, 6h and 8 hours. Also the mean time to the first request of morphine, was longer in Groups II and III than in Group I. Group III was significantly longer than Group II. The total dose of post-operative morphine consumption in Group II and Group III were lower than that in Group I. There was significantly lower total dose of post-operative morphine consumption in Group III than Group II.
Conclusion: Both the posterior and subcostal US TAP block provides superior analgesia than the standard IV regimen. However, beyond the initial 4 hours after recovery, patients in the subcostal TAP group had significantly lower pain scores than did patients from the other groups.