Design of a Handheld Tissue Grasping Device to Measure Tissue Mechanical Properties In-Vivo or in a Laboratory Setting

Drahos, Bradley A.; Safdari, Amer; Malik, Faizan A; Smith, Rebecca; Kubala, Matthew; Norfleet, Jack; Parsey, Conner; Goodwin, Shikha Jain; Kowalewski, Timothy M.

doi:10.1115/dmd2020-9089

Cited by 2 publications

(3 citation statements)

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“…A detailed discussion of the grasping device and its measurement performance is described in S2 Fig. and Drahos et al [7]. The device contains two opposing load cells (TAL220B, HT Sensor Technology) in a scissor-like fashion, with 3Dprinted hemispherical plastic tips serving as the grasping surface and a quadrature rotary encoder (AMT102-V, CUI Inc.) to measure the angle of the arms as the device opens to monitor tissue thickness and overall displacement.…”

Section: Grasping Device Designmentioning

confidence: 99%

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Variability of tissue mechanical response in Sus Domesticus porcine models from in vivo to ex vivo conditions

et al. 2023

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Background Healthcare simulators have been demonstrated to be a valuable resource for training several technical and nontechnical skills. A gap in the fidelity of tissues has been acknowledged as a barrier to application for current simulators; especially for interventional procedures. Inaccurate or unrealistic mechanical response of a simulated tissue to a given surgical tool motion may result in negative training transfer and/or prevents the “suspension of disbelief” necessary for a trainee to engage in the activity. Thus, where it is relevant to training outcomes, there should be an effort to create healthcare simulators with simulated tissue mechanical responses that match or represent those of biological tissues. Historically, this data is most often gathered from preserved (post mortem) tissue; however, there is a concern that the mechanical properties of preserved tissue, that lacks blood flow, may lack adequate accuracy to provide the necessary training efficacy of simulators. Methods and findings This work explores the effect of the “state” of the tissue testing status on liver and peritoneal tissue by using a customized handheld grasper to measure the mechanical responses of representative porcine (Sus domesticus) tissues in n = 5 animals across five test conditions: in vivo, post mortem (in-situ), ex vivo (immediately removed from fresh porcine cadaver), post-refrigeration, and post-freeze-thaw cycle spanning up to 72 hours after death. No statistically significant difference was observed in the mechanical responses due to grasping between in vivo and post-freeze conditions for porcine liver and peritoneum tissue samples (p = 0.05 for derived stiffness at grasping force values F = 5N and 6.5N). Furthermore, variance between in vivo and post-freeze conditions within each animal, was comparable to the variance of the in vivo condition between animals. Conclusions Results of this study further validate the use of preserved tissue in the design of medical simulators via observing tissue mechanical responses of post-freeze tissue comparable to in vivo tissue. Therefore, the use of thawed preserved tissue for the further study and emulation of mechanical perturbation of the liver and peritoneum can be considered. Further work in this area should investigate these trends further, particularly in regard to other tissues and the potential effects varying preservation methods may yield.

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Section: Grasping Device Designmentioning

confidence: 99%

“…Source code for the application can be found through S1 File. The application also displayed a real-time graph of the data, as shown in Drahos et al [7]. We also used the application to calibrate the load cells, as detailed in S5 Fig.…”

Section: Grasping Device Operationmentioning

confidence: 99%

Variability of tissue mechanical response in Sus Domesticus porcine models from in vivo to ex vivo conditions

et al. 2023

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“…The computer ran the "Scissors Console" application, which sampled the voltage and encoder data at 1000 Hz, and stored the data in CSV files defined by the user. The application also displayed a real-time graph of the data, as shown in Drahos et al (9). Additionally, the application produced a series of audio tones at fixed time intervals to foster consistent grasp timings; a "grasp tone" was played for 1.5 seconds, with a delay of 1.7 seconds until the next tone.…”

Section: Grasping Device Operation Setupmentioning

confidence: 99%

Variability of Tissue Mechanical Response in Sus Domesticus Porcine Models from in vivo to ex vivo Conditions

Malik

Drahos

Safdari

et al. 2022

Preprint

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Healthcare simulators have been demonstrated to be a valuable resource for training several technical and nontechnical skills. A gap in the fidelity of tissues has been acknowledged as a barrier to application for current simulators; especially for interventional procedures. Inaccurate or unrealistic mechanical response of a simulated tissue to a given surgical tool motion may result in negative training transfer and/or prevents the “suspension of disbelief” necessary for a trainee to engage in the activity. Thus, where it is relevant to training outcomes, there should be an effort to create healthcare simulators with simulated tissue mechanical responses that match or represent those of biological tissues. Historically, this data is most often gathered from preserved (post mortem) tissue; however, there is a concern that the mechanical properties of preserved tissue, that lacks blood flow, may lack adequate accuracy to provide the necessary training efficacy of simulators. This work explores the effect of the “state” of the tissue testing status on liver and peritoneal tissue by using a customized handheld grasper to measure the mechanical responses of representative porcine (Sus domesticus) tissues in N=5 animals across five test conditions: in vivo, postmortem (in-situ), ex vivo (immediately removed from fresh porcine cadaver), post-refrigeration, and post-freeze-thaw cycle spanning up to 72 hours after death. No statistically significant difference was observed in the mechanical responses due to grasping between in vivo and post-freeze conditions for porcine liver and peritoneum tissue samples (p = 0.05 for derived stiffness at grasping force values F = 5N and 6.5N). Furthermore, variance between in vivo and post-thaw conditions within each animal, was comparable to the variance of the in vivo condition between animals. Thus, the use of thawed, preserved tissue for the further study and emulation of mechanical perturbation of the liver and peritoneum can be considered.

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Design of a Handheld Tissue Grasping Device to Measure Tissue Mechanical Properties In-Vivo or in a Laboratory Setting

Cited by 2 publications

References 0 publications

Variability of tissue mechanical response in Sus Domesticus porcine models from in vivo to ex vivo conditions

Variability of tissue mechanical response in Sus Domesticus porcine models from in vivo to ex vivo conditions

Variability of Tissue Mechanical Response in Sus Domesticus Porcine Models from in vivo to ex vivo Conditions

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