Discussion
Scimia, postoperative pain, hernia, thoracolumbar
CHRONIC PAIN, COMPLICATIONS, COMPLICATION
This randomized, controlled non-inferiority study compared the postoperative analgesia profile of TFB versus QLB in children undergoing inguinal herniotomy. We did not find statistically significant differences between TFB and QLB in the proportion of patients who required rescue analgesia and the postoperative pain score. However, the time needed to perform TFB was significantly shorter compared with QLB. On sub-analysis of patients’ data who needed rescue analgesia, there were no significant differences in the time to first analgesic request and analgesic consumption between both groups. We did not report the incidence of any complication due to performing TFB or QLB.In this study, the non-inferiority margin for the proportion of patients who required rescue analgesia was 0.25 (25%) and the 95% confidence interval was (21–28) %. Therefore, the non-inferiority of TFB to QLB was not confirmed as the non-inferiority margin (25%) was lower than the upper 95% confidence interval (28%).Previous studies have demonstrated that both TFB and QLB are effective in reducing postoperative pain scores and analgesic consumption after inguinal hernia repair [López-González et al. compared the postoperative analgesic efficacy of ultrasound-guided the TFB versus the transversus abdominis plane (TAP) block in adults undergoing outpatient inguinal hernia repair [An adult study by Fouad et al. used a similar methodology to compare the postoperative analgesia profile of TFB versus QLB in patients scheduled for unilateral inguinal hernia repair [Scimia et al. reported that the ultrasound-guided TFB could provide a satisfactory analgesia and anesthesia of the dermatomes innervated by T12–L1 nerves [Öksüz et al. compared the postoperative analgesia of the QLB versus the TAP block in children who underwent open surgery for unilateral inguinal herniotomy or orchiopexy [Ragab et al. in a randomized study, compared the analgesic effects and parents’ satisfaction of quadratus block versus the caudal block in children undergoing open inguinal hernia repair [The main sensory innervation of the inguinal region arises from T10-L2 nerves. The ilioinguinal and iliohypogastric nerves originate from T12 and L1 nerves [The main mechanism of QLB is the spread of the local anesthetic along the thoracolumbar fascia to the paravertebral space to block the spinal nerves [Consistent with the findings of our study, Fouad et al. [The current study demonstrated good control of the hemodynamic response to the intraoperative stressful conditions such as skin incision and traction on the hernia sac in TFB and QLB groups because we performed both blocks before skin incision. Tian et al. used different concentration of ropivacaine for TFB in adult patients undergoing laparotomy and found that the perioperative HR and MAP were more stable and the postoperative pain score was significantly lower with the medium concentration than the low concentration of ropivacaine [In this study, the parents were satisfied from the postoperative analgesia of TFB and QLB because the patients were calm, comfortable and easily sleep. We did not report the incidence of any complications related to the block indicating the safety of both TFB and QLB.Our study has few important limitations. First, we did not measure the serum concentration of bupivacaine because of the unavailability of this analysis in our hospital. Second, we did not assess the dermatomal sensory spread of TFB and QLB because both blocks were performed under general anesthesia. Third, we did not evaluate the effect of TFB and QLB on the incidence of chronic pain after inguinal hernia repair as this requires the patients follow up for several months. Lastly, we couldn’t accurately comment on the safety of TFB and QLB because of the small sample size, therefore future studies with larger sample size are required.