Effect of transversus abdominis plane block with or without buprenorphine after inguinal hernia surgery on postoperative pain

Introduction:
Transversus abdominis plane (TAP) has been mentioned as having bene­ficial effects on chronic pain after hernioplasty. This study assessed the effects of TAP block on acute and persistent postoperative pain after inguinal hernia surgery, with or without buprenorphine.

Material and methods:
64 patients were allocated to group R (n = 32) and received 20 mL of 0.25% ropivacaine for TAP block; group RB (n = 32) received 20 mL of 0.25% ropivacaine containing 300 µg of buprenorphine for TAP block. The primary outcome was the analgesic and antihyperalgesic effect of buprenorphine. The duration of analgesia, analgesic consumption, postoperative pain scores at rest and sitting up to 48 hours, and the effect on wound hyperalgesia were evaluated. Secondary outcomes included the incidence of side effects and complications.

Results:
The median (IQR) duration of analgesia in group R was 386.5 (37.25) minutes vs. 868 (41.3) minutes in the RB group. Median pain scores on sitting were found to be significantly better in group RB than in group R at 6, 12, and 24 hours (P < 0.001). The wound hyperalgesia index showed a significant difference between groups (P < 0.001). The incidence of persistent postoperative pain was 6.25% in the R group, as compared to 0% in the RB group. Otherwise, the patients did not have any further complications associated with the block.

Conclusions:
The results demonstrated that TAP block with buprenorphine reduced acute postoperative pain severity, but we did not find a difference between groups in persistent pain.