Comparison of the Postoperative Analgesic Effects of Levobupivacaine Wound Instillation with a Placebo after Unilateral Inguinal Hernia Repair: a Randomized-controlled Trial

Abstract

Objective − To compare the effectiveness and safety of wound instillation with levobupivacaine with a placebo, in children who underwent inguinal hernia repair, for pain relief. The secondary objective was to examine the frequency of postoperative analgesic mixture (paracetamol/ibuprofen) use.

Methods − Single center randomized placebo-controlled trial. Paediatric teaching hospital in Belgrade, Serbia. This study included 100 children who underwent elective surgery for unilateral inguinal hernia. Children were randomized by simple randomization into two groups (N=50 in the experimental group, N=50 in the control group). A solution of 0.5% levobupivacaine, 0.5 mg/kg (0.1 ml/kg) was instilled into the wounds of children in the experimental group before suturing the abdominal fascia. The same amount of 0.9% saline was administered to the children in the control group. The primary outcome was the level of postoperative pain after coming round from general anesthesia (t0) and at 2h, 6h, 12h, 18h and 24h after surgery. The FLACC (Face, Legs, Activity, Cry, Consolability) scale was used to assess the level of pain. The secondary outcome was the frequency of paracetamol/ibuprofen use for pain relief after surgery.

Results − Out of the total number of children (100), 70% were boys (70) and 30% were girls (30), and their average age was 3.5±1.9 years. The average duration of surgical intervention in both groups was 31.6±4.2 minutes. Significantly fewer children in the experimental group reported pain (FLACC ≥1) at 2h (P=0.032) and 6h (P=0.001) after surgery, compared to the children in the control group (8 vs. 17 at 2h after surgery; 4 vs. 14 at 6h after surgery). Significantly fewer children in the control group reported sensations of pain that required administration of analgesics 6h after surgery (FLACC >3) compared to the control group (P=0.001) (1 vs. 14). Overall, significantly fewer children in the experimental group received a paracetamol/ibuprofen mixture for pain relief after surgery, compared to the children in the control group (P<0.001) (4 vs. 50). The average daily amount of acetaminophen in the experimental group was 28±127 mg/kg/day and ibuprofen 5.6±1.8 mg/kg/day, while in control group, acytaminophen 42.5±7.7 mg/kg/day and ibprofen 11.5±4 mg/kg/day. The total amount of analgesics was highly statistically significantly lower in the experimental group (P<0.001).

Conclusion − Instillation of levobupivacaine before wound suturing in children who had undergone elective inguinal hernia surgery repair was effective in postoperative pain relief. Children who received levobupivacaine also received less of the paracetamol/ibuprofen mixture to relieve their pain over 24 hours after surgery.