Mechanical characterisation of soft materials of EBUS-TBNA

Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is a biopsy procedure used for sampling lymph node tissue to stage cancers and diagnose granulomatous disease. The failure of this diagnostic procedure through inadequate tissue sample capture by the needle can affect the treatment of patients. In this study, tissue sampling is being explored through mechanical testing and finite element analysis (FEA). The mechanical testing was carried out on phantoms and various soft tissues on a displacement-control basis using the Mach-1 V500C (Biomomentum Inc, Quebec, Canada). The FEA was carried out on a complementary basis using the element deletion-based method to model a bevel-tipped needle interacting with phantom material. The results of this study confirm the nature of soft tissue as being hyperelastic and that Abaqus FEA (Dassault Systemѐs, Vélizy-Villacoublay, France) is a valuable tool to consider the optimum needle design to maximize the diagnostic yield from the biopsy.