Tissueshift: A shape dependent phenomenon with clinical relevance

Introduction Tissue shift (TS) is the term used for shifts of soft tissue in surgery. So far, there are no studies on TS depending on the shape of the tumor (TU) and the shape resection cavity (RC).

Methods We developed an AI-supported software that captures shape-dependent TS. In a pig cadaver model, n=40, tissues of different shapes were removed and exposed to different temperatures. This led to a change in volume (ΔV) through alteration of elastic properties and desiccation of the tissue, which produced a TS. The tissue surfaces were scanned with a 3D camera (n=400) and ΔV calculated.

Results At 36.4±1.3°C, ΔV is increased especially in concave formations (p<0.0001). At 7.9±4.1°C there is no difference between concave and convex (p=0.06). Irregularly shaped convex patterns are exposed to significantly higher TS than compact convex shapes (p=0.0159).

Discussion In cadaver models, large amounts of data can be collected to train an AI. Concave shapes (≙RC) are subject to a larger TS than convex shapes (≙TU). This is intensified with irregularly shaped TU, which occurs e.g. in metastases and salivary gland TU. It is also of interest for the planning of flaps if their extent should be estimated before/during the TU removal. Due to the stronger TS of the RC compared to the TU, the flap can later have difficulties fitting. When assigning intraoperative frozen section findings, the higher TS in the RC can lead to shifts in landmarks, which result in incorrect assessment and incorrect re-resection. Although this has so far only been based on experimental ΔV data, the relevance of the shape-dependent TS can still be assumed and, maybe, used for surgical planning.

ZIM FuE-Kooperationsprojekt Nr. KK5044704CS0

Publication History

Article published online:
12 May 2023