P2.D066: Comparative Study of Ultrasound-Guided Nerve Blocks for Pediatric Femur Fractures

Background: Ultrasound-guided nerve blocks can be considered as a pain management method for pediatric femur fractures. However, limited pediatric data from case reports and retrospective studies in emergency settings prompts uncertainty regarding the superior technique. Our objective was to prospectively compare the efficacy and safety of ultrasound-guided fascia iliaca nerve block (FINB) versus femoral nerve block (FNB) in pediatric patients.

Methods: We conducted a preliminary subgroup analysis comparing FINB versus FNB within a larger prospective, multi-center observational study across five pediatric emergency departments (PED) in the United States and Australia. Eligible participants were children aged 4-17 years with femur fractures sustained within 24 hours, a Glasgow Coma Scale ≥ 14, and injuries limited to the lower extremities. Exclusion criteria included neurovascular compromise, bilateral femur fractures, pregnancy, and known allergy to local anesthetic agents. FNB was defined as needle tip visualization within 5 mm of the femoral nerve under ultrasound, while FINB was defined as needle visualization ≥ 5 mm lateral to the femoral nerve. Primary outcome was pain reduction 60 minutes post-procedure using the Faces Pain Scale-Revised. Secondary outcomes included post-procedure opioid administration and adverse events such as lidocaine-associated systemic toxicity and neurovascular injury. Institutional guidelines governed the procedure. Statistical analyses employed paired t-tests, standard t-tests, and Fisher’s exact test. The study protocol received approval from each site’s Institutional Review Board.

Results: Analysis involved 23 participants, predominantly with displaced mid-shaft (74%) femur fractures. In the FINB group, consisting of 11 patients with a mean age of 11.8 years, pain scores significantly decreased from 5.7 to 1.3 at 60 minutes (95% CI 2.4-6.5; t(10) = 4.9, p < 0.01). Similarly, the FNB group, comprising 12 patients with a mean age of 8.7 years, experienced a significant reduction in mean pain scores from 6.6 to 1.7 at 60 minutes (95% CI 3.1-6.7; t(11) = 5.9, p < 0.01). The reduction in mean pain scores (4.4 versus 4.9) was comparable between both groups (p=0.71). Post-procedure opioid administration was observed in 4/11 (36%) FINB patients and 3/12 (25%) FNB patients (p=0.67). No serious cardiopulmonary, neurological, or local site-specific adverse reactions were reported in either group. Enrollment in our larger study comparing ultrasound guided regional analgesia to opioid administration is ongoing.

Conclusion: This preliminary analysis demonstrates the feasibility and effectiveness of both FINB and FNB in managing pain among pediatric patients with acute femur fractures. Additionally, we observed a reduced requirement for opioid administration and the absence of serious safety events. Further research is necessary to determine potential benefits of one technique over the other for specific patients or fracture subtypes.