Needle insertion-induced quasiperiodic cone cracks in hydrogel

Abstract

Needle insertion, a standard process for various minimally invasive surgeries, results in tissue damage which sometimes leads to catastrophic outcomes. Opaqueness and inhomogeneity of the tissues make it difficult to...

How friction and adhesion affect the mechanics of deep penetration in soft solids

“…This model is based on the hypothesis of planar crack formation. However, some experimental results show different crack morphologies, like ring-shaped cracks, 14,28,29 conical cracks, 15 or more complex morphologies. 30 In these scenarios, our prediction could be inaccurate, and one would have to extend our model to account for complex crack morphologies.…”

Cone cracks in tissue-mimicking hydrogels during hypodermic needle insertion: the role of water content

“…This results in immediate relaxation of the stress and the stretched surface relaxes back, reducing COD as can be seen in Fig. 12. 10…”

“…The experiments were carried out using an in-house, programmable servo motor-based displacement-controlled needle insertion system. 10 The insertion and retraction forces were measured using an S type strain gauge-based load cell. The needle displacement was measured using a linear variable differential transformer (LVDT) connected to the linear displacement system.…”

“…7,11,14,15,17,20,21 Recently, we have shown that multiple peaks in the insertion force correspond to axisymmetric, stable, and quasiperiodic cone cracks. 10…”

“…6,8,9 Recently, we have shown that cone cracks with well-defined geometry and periodic spacing are generated in polyacrylamide (PAAm) hydrogels during needle penetration. 10 Understanding the nucleation and propagation of these cone cracks as a function of properties of the tissues is important either to minimise these cracks or purposefully induce these cracks where needed. In this study, we explored the cone cracks produced in hydrogels with different water contents to mimic various soft tissues.…”