Table of Contents
Journal of Medical Engineering
Volume 2016 (2016), Article ID 5162394, 8 pages
Research Article

The Biomechanics and Optimization of the Needle-Syringe System for Injecting Triamcinolone Acetonide into Keloids

1Department of Diagnostic Imaging, University of Alberta, Edmonton, AB, Canada
2Faculty of Mechanical Engineering, University of Ottawa, Ottawa, ON, Canada
3Division of Plastic Surgery, Department of Surgery, University of Ottawa, Ottawa, ON, Canada

Received 9 May 2016; Accepted 7 September 2016

Academic Editor: Nivaldo Antonio Parizotto

Copyright © 2016 Anthony Vo et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Purpose. Injecting triamcinolone acetonide (TA) into a keloid is physically challenging due to the density of keloids. The purpose was to investigate the effects of various syringe and needle combinations on the injection force to determine the most ergonomic combination. Materials and Methods. A load cell was used to generate and measure the injection force. Phase 1: the injection force of 5 common syringes was measured by injecting water into air. The syringe that required the lowest injection force was evaluated with various needle gauges (25, 27, and 30 G) and lengths (16, 25, and 38 mm) by injecting TA (40 mg/mL) into air. The needle-syringe combination with the lowest injection force (CLIF) was deemed the most ergonomic combination. Phase 2: comparisons between the CLIF and a standard combination (SC) were performed by injecting TA into air and tap water into a keloid specimen. Intraclass Correlation Coefficient (ICC) and independent -test were used. Results. Increasing the syringe caliber, injection speed, and needle gauge and length significantly increased the injection force ( value < 0.001). The SC required a maximum force of 40.0 N to inject water into keloid, compared to 25.0 N for the CLIF. Injecting TA into keloid using the SC would require an injection force that was 103.5% of the maximum force female thumbs could exert compared to 64.8% for the CLIF. ICC values were greater than 0.4. Conclusions. The 1 mL polycarbonate syringe with a 25 G, 16 mm needle (CLIF) was the most ergonomic combination. The SC required a substantial injection force, which may represent a physical challenge for female thumbs.