Methylene Blue Combined with Ropivacaine for Intercostal Nerve Block After Autologous Costal Cartilage Removal in Juvenile Patients

Objectives: Autologous costal cartilage is commonly used as a graft material in plastic surgery. However, after autologous costal cartilage removal, the pain at the surgical site is particularly strong. We conducted this controlled clinical study to verify the efficacy of methylene blue (MB) in intercostal nerve block after autologous costal cartilage removal and to provide a reference for the application of MB in postoperative analgesia after autologous costal cartilage removal.

Methods: In this study, 90 adolescent patients with congenital microtia who underwent autologous rib cartilage graft for auricular reconstruction were randomly allocated to one of three groups (Group A: intercostal nerve block was performed with 0.75% ropivacaine; Group B: intercostal nerve block was performed with 1% MB; and Group C: intercostal nerve block was performed with 1% MB and 0.75% ropivacaine mixture). Two trained researchers observed and recorded the pain status of the children at 6 hours (T1), 24 hours (T2), 48 hours (T3), and 72 hours (T4) after surgery, respectively. Numerical rating pain scale (NRS) was used for scoring. And adverse reactions such as nausea, vomiting, and skin itching were recorded.

Results: In this study, there was no statistical difference in age and gender of patients in Groups A, B, and C (P >0.05). In terms of NRS comparison, 6 hours after operation (T1), Group B > Group A > Group C (P< 0.05); 24 hours after operation (T2), Group B > Group A > Group C (P< 0.05); 48 hours after operation (T3), Group B > Group A > Group C (P< 0.05); 72 hours after operation (T4), Group A > Group B > Group C (P< 0.05). There were no statistically significant differences in postoperative nausea, vomiting, and skin itching among the three groups (P>0.05).

Conclusion: The analgesic effect of IV self-controlled analgesia combined with ropivacaine is quick, but the maintenance time is short. The analgesic effect of IV self-controlled analgesia combined with MB is slow to onset but long to maintain. The analgesic effect of IV self-controlled analgesia combined with MB and ropivacaine mixture is quick and maintained for a long time. Therefore, in patients after removal of costal cartilage, we recommend the analgesic treatment method of IV self-controlled analgesia combined with MB and ropivacaine mixture.

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