A 3D digital image correlation framework for skin strain analysis with application to the peripheral intravenous...

Quantifying full field skin strain at the interface between medical devices and human tissue is a persistent challenge in clinical biomechanics, with direct relevance to device securement, micro-motion, and failure mechanisms such as peripheral intravenous catheter (PIVC) dislodgement. This work presents a 3D digital image correlation (DIC) framework that enables in vivo quantification of skin-device interface strain, validated through rigid body motion and uniaxial testing to sub-pixel accuracy. A reproducible stencil/stamp speckle patterning method is introduced to ensure consistent, customisable, high-contrast patterns suitable for skin imaging. The framework is demonstrated in vivo at the antecubital fossa beneath a PIVC dressing, where region based effective strain analysis reveals a clear mechanical hierarchy at the skin-device interface, with strain concentrating in the peri-insertion tissue at the dressing margin. The system is implemented on accessible open hardware and software, lowering the cost barrier to adoption, with implications for biomechanical research, medical device evaluation, and experimental mechanics.