Abstract
OBJECTIVES: To use 3D imaging modalities to obtain precise measurements of the proximal tibia in pediatric patients and assess the safety of current intraosseous needle lengths (15 and 25 mm). DESIGN: Retrospective descriptive study. SETTING: University of Minnesota and MHealth Fairview System, Minneapolis, MN. PATIENTS: Pediatric patients (≤ 16 yr) who underwent full-body positron emission tomography-CT or axial MRI scans of the lower extremities between January 2014 and December 2023. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: A total of 912 scans were initially retrieved; 232 scans were excluded due to osseous diseases, tibial fractures, suboptimal scan quality, or soft-tissue abnormalities, leaving 680 scans for analysis. Scans were stratified into 1-year age groups. Measurements at the proximal tibia included soft-tissue thickness, cortical bone thickness, and medullary canal diameter. Other values, such as the pre-intraosseous space (sum of cortical thickness and soft-tissue depth) and total distance to deep cortex, were calculated. Simulated needle insertions demonstrated that 31.62% of the 15 mm needles were too shallow, failing to reach the medullary canal, whereas 34.85% of the 25 mm needles were too deep, both of which could cause severe complications. A cutoff analysis for needle size based on age rather than weight was also calculated. For the 15 mm needle, 95% CI was not found in any age range, and the highest confidence cutoff was for using the needle in the age range of 0-8 years (91.9%). The 25 mm needle had a 97.8% CI from ages 10-16. CONCLUSIONS: The study reveals significant age-related variability in the proximal tibia's anatomical dimensions, suggesting that standard 15 and 25 mm intraosseous needles may not reliably achieve optimal placement in pediatric patients. Our findings indicate that the current intraosseous needles may not be as safe as previously thought and support the need to develop improved intraosseous needle designs to enhance safety and therapeutic effectiveness in pediatric emergency care.