Abdominal muscles infiltration analgesia for donor-site pain in autologous ear reconstruction: A randomized controlled clinical trial.

Background: Costal cartilage donor-site pain is an adverse effect of autologous ear reconstruction. This study aimed to introduce rectus abdominis and external oblique muscle infiltration analgesia (RAM+EOM-IA) for costal cartilage donor-site pain and evaluate its efficacy and safety.

Methods: The study was a randomized controlled clinical trial. Patients were randomized between intermittent RAM+EOM-IA combined with intravenous patient-controlled anesthesia (IPCA) and IPCA alone. Thirty patients were followed in the RAM+EOM-IA combined with the IPCA group and 30 patients in the IPCA alone group. The primary outcome was the numerical rating score (NRS) of pain recorded during 48 h postoperatively. Secondary outcomes included the Barthel index (BI) and rescue analgesic consumption. Sensory block areas were tested using a cold stimulus.

Results: NRS was significantly lower with RAM+EOM-IA combined with IPCA than with IPCA alone at 28 h (P < 0.01), 32 h (P < 0.01), 36 h (P < 0.01), 44 h (P < 0.001), and 48 h (P < 0.01) postoperatively. The number of patients who received rescue analgesics (P < 0.01) and consumption (P < 0.01) was significantly higher for IPCA alone. RAM+EOM-IA improved the BI at 24 h postoperatively (P < 0.001), especially for mobility (P < 0.001), using the stairs (P < 0.001) and toilet use domains (P < 0.001). At 10 and 60 min after RAM+EOM-IA, the total sensory block area in the abdomen had not extended proximally beyond the xiphoid, distally beyond the navel, and beyond midaxillary and midsternal lines on either side.

Conclusion: RAM+EOM-IA effectively and safely prevented costal cartilage donor-site pain by blocking anterior and lateral cutaneous branches of intercostal nerves from T6 to T10 in microtia patients.