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Early Stage Researcher (PhD Year 1) Post-Doctoral Researcher/Senior Researcher/PI Entry for the Engineers Ireland Biomedical Research Medal Corresponding author has completed PhD and would like to review BinI abstract submissions Please place an X in any appropriate categories INTRODUCTION The intradural venous sinuses play an integral role in draining venous blood from the cranial cavity. As a result of the sinuses anatomical location, they are of significant importance when evaluating the mechanopathology of traumatic brain injury (TBI). Despite the importance of the intradural sinuses in normal neurophysiology and in the study of TBI, no biomechanical analyses have been conducted on the tissues [1]. This work represents the first mechanical and structural characterisation of the cortical venous sinuses. MATERIALS AND METHODS 12 porcine heads were acquired from a local abattoir. Cortical venous sinus tissue was isolated from the heads within 4 hours of animal euthanasia. The dural sinuses were sectioned into 4 regions of interest (see figure 1). Samples from the superior sagittal sinus region were prepared for either ring testing or uniaxial tensile testing. Ring test samples were cut into strips of width 2-3 mm. Uniaxial tensile test samples were dissected into 30 x 4 mm (l x w) segments. Samples for uniaxial tensile testing were speckled with a tissue staining dye using an airbrush prior to mechanical testing to facilitate DIC analysis. Samples were then subjected to 10 preconditioning cycles followed by a characterisation stretch using the CellScale Biotester. RESULTS AND DISCUSSION Here we present the first investigation of cortical venous sinus circumferential stress-strain behaviour. We show that the porcine venous sinuses exhibit high strain region moduli ranging from ~ 3 to 5 MPa in the circumferential direction (see Fig. 1 (a)). These circumferential mechanics findings are particularly important in the context of endovascular angioplasty procedures conducted frequently in the treatment of common sinus pathologies [1]. With longitudinal elastic moduli values ranging from 33 MPa to 58 MPa (see Fig. 1(b)), we demonstrate that the sinuses exhibit higher mechanical stiffness than that of native dura mater tissue [2], which has important Bioengineering in Ireland 26 , January 17-18, 2020 MECHANICAL AND STRUCTURAL CHARACTERISATION OF THE CORTICAL VENOUS SINUSES Walsh, D.R. 1,2,3 , Lynch, J. 1,2,3 , O’ Connor, D.T. 1,2,3 , Newport, D.T. 1,2 , Mulvihill, J.J.E 1,2,3 1 Bernal Institute, University of Limerick, Limerick, Ireland 2 School of Engineering, University of Limerick, Limerick, Ireland 3 Health Research Institute, University of Limerick, Limerick Ireland email: [email protected]
Transcript of WordPress.com · Web view2020. 1. 6. · Walsh, D.R. 1,2,3, Lynch, J. 1,2,3, O’ Connor, D.T....
Early Stage Researcher (PhD Year 1) Post-Doctoral Researcher/Senior Researcher/PI
Entry for the Engineers Ireland Biomedical Research Medal
Corresponding author has completed PhD and would like to review BinI abstract submissions
Please place an X in any appropriate categories
INTRODUCTION
The intradural venous sinuses play an integral role in draining venous blood from the cranial cavity. As a result of the sinuses anatomical location, they are of significant importance when evaluating the mechanopathology of traumatic brain injury (TBI). Despite the importance of the intradural sinuses in normal neurophysiology and in the study of TBI, no biomechanical analyses have been conducted on the tissues [1]. This work represents the first mechanical and structural characterisation of the cortical venous sinuses.
MATERIALS AND METHODS
12 porcine heads were acquired from a local abattoir. Cortical venous sinus tissue was isolated from the heads within 4 hours of animal euthanasia. The dural sinuses were sectioned into 4 regions of interest (see figure 1).Samples from the superior sagittal sinus region were prepared for either ring testing or uniaxial tensile testing. Ring test samples were cut into strips of width 2-3 mm. Uniaxial tensile test samples were dissected into 30 x 4 mm (l x w) segments. Samples for uniaxial tensile testing were speckled with a tissue staining dye using an airbrush prior to mechanical testing to facilitate DIC analysis. Samples were then subjected to 10 preconditioning cycles followed by a characterisation stretch using the CellScale Biotester.
RESULTS AND DISCUSSION
Here we present the first investigation of cortical venous sinus circumferential stress-strain behaviour. We show that the porcine venous sinuses exhibit high strain region moduli ranging from ~ 3 to 5 MPa in the circumferential direction (see Fig. 1 (a)). These circumferential mechanics findings are particularly important in the context of endovascular angioplasty procedures conducted frequently in the treatment of common sinus pathologies [1].With longitudinal elastic moduli values ranging from 33 MPa to 58 MPa (see Fig. 1(b)), we demonstrate that the sinuses exhibit higher mechanical stiffness than that of native dura mater tissue [2], which has important implications for the field of TBI modelling.
Figure 1 (a) Mean elastic moduli results for the samples tested in the circumferential test direction utilising ring testing.
(b) Mean elastic moduli results for the samples tested in the longitudinal test direction utilising uniaxial tensile testing. Note that the y-axis scale differs between (a) and (b). (c) Van Giesons histology of sinus. (d) SEM imaging of sinus.
Finally, histological staining analysis and scanning electron microscopy imaging of the sinuses (Fig. 1 (c) and (d)) identified a dense, highly aligned collagenic network within the tissue, which may explain its high stiffness.
CONCLUSION
We provide the first in-depth analysis of the cortical venous sinus biomechanical behaviour and structure, which has important implications for sinus-related neurosurgical procedures and for understanding TBI mechanopathology. These findings enable improved biofidelity in the computational modelling of head impacts and have the potential to improve the efficacy of TBI preventative measures. Future work will focus on replicating this analysis on human cadaveric tissue for improved translatability of results.
REFERENCES
[1] MR Levitt et al., AJNR. American journal of neuroradiology 37 (10), 1876 (2016).
[2] JE Galford and JH McElhaney, J Biomech 3 (2), 211 (1970).
Bioengineering in Ireland26, January 17-18, 2020
MECHANICAL AND STRUCTURAL CHARACTERISATION OF THE CORTICAL VENOUS SINUSES
Walsh, D.R. 1,2,3, Lynch, J. 1,2,3, O’ Connor, D.T. 1,2,3, Newport, D.T.1,2, Mulvihill, J.J.E 1,2,3
1 Bernal Institute, University of Limerick, Limerick, Ireland2 School of Engineering, University of Limerick, Limerick, Ireland
3 Health Research Institute, University of Limerick, Limerick Irelandemail: [email protected]
Early Stage Researcher (PhD Year 1) Post-Doctoral Researcher/Senior Researcher/PI
Entry for the Engineers Ireland Biomedical Research Medal
Corresponding author has completed PhD and would like to review BinI abstract submissions
Please place an X in any appropriate categories
Bioengineering in Ireland26, January 17-18, 2020
