Linking microvascular collapse to tissue hypoxia in a multiscale model of pressure ulcer initiation

Sree, Vivek D.; Rausch, Manuel K.; Tepole, Adrián Buganza

doi:10.1007/s10237-019-01187-5

Cited by 23 publications

(13 citation statements)

References 88 publications

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“…Another example is pressure sore initiation in individuals who are bed-or wheelchair-ridden [16][17][18]. Among other factors, such as ischemia and inflammation [19,20], friction between the skin of these individuals and textiles or common materials used in wheelchair or prostheses design can contribute to abrasion and skin damage, paving the way for more serious chronic wounds [7,[21][22][23]. Other applications for which anticipating skin pressure and friction are important include the design of shoes and clothing for diabetic individuals, wearable robots for rehabilitation, exoskeletons for soldiers, and sports equipment [24].…”

Section: Introductionmentioning

confidence: 99%

Changes in the three-dimensional microscale topography of human skin with aging impact its mechanical and tribological behavior

et al. 2021

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Human skin enables interaction with diverse materials every day and at all times. The ability to grasp objects, feel textures, and perceive the environment depends on the mechanical behavior, complex structure, and microscale topography of human skin. At the same time, abrasive interactions, such as sometimes occur with prostheses or textiles, can damage the skin and impair its function. Previous theoretical and computational efforts have shown that skin’s surface topography or microrelief is crucial for its tribological behavior. However, current understanding is limited to adult surface profiles and simplified two-dimensional simulations. Yet, the skin has a rich set of features in three dimensions, and the geometry of skin is known to change with aging. Here we create a numerical model of a dynamic indentation test to elucidate the effect of changes in microscale topography with aging on the skin’s response under indentation and sliding contact with a spherical indenter. We create three different microrelief geometries representative of different ages based on experimental reports from the literature. We perform the indentation and sliding steps, and calculate the normal and tangential forces on the indenter as it moves in three distinct directions based on the characteristic skin lines. The model also evaluates the effect of varying the material parameters. Our results show that the microscale topography of the skin in three dimensions, together with the mechanical behavior of the skin layers, lead to distinctive trends on the stress and strain distribution. The major finding is the increasing role of anisotropy which emerges from the geometric changes seen with aging.

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Section: Introductionmentioning

confidence: 99%

Changes in the three-dimensional microscale topography of human skin with aging impact its mechanical and tribological behavior

et al. 2021

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“…We realize that axial pattern or distant flap transfer for scalp reconstruction would follow the vascular pattern of the respective flaps. Consideration of features such as vascular pattern into the FE model is possible as has been demonstrated recently (Sree et al, 2019).…”

Section: Discussionmentioning

confidence: 99%

Personalized Computational Models of Tissue-Rearrangement in the Scalp Predict the Mechanical Stress Signature of Rotation Flaps

Lee

Turin

Stowers

et al. 2020

The Cleft Palate Craniofacial Journal

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Objective: To elucidate the mechanics of scalp rotation flaps through 3D imaging and computational modeling. Excessive tension near a wound or sutured region can delay wound healing or trigger complications. Measuring tension in the operating room is challenging, instead, noninvasive methods to improve surgical planning are needed. Design: Multi-view stereo allows creation of 3D patient-specific geometries based on a set of photographs. The patient-specific 3D geometry is imported into a finite element (FE) platform to perform a virtual procedure. The simulation is compared with the clinical outcome. Additional simulations quantify the effect of individual flap parameters on the resulting tension distribution. Participants: Rotation flaps for reconstruction of scalp defects following melanoma resection in 2 cases are presented. Rotation flaps were designed without preoperative FE preparation. Main Outcome Measure: Tension distribution over the operated region. Results: The tension from FE shows peaks at the base and distal ends of the scalp rotation flap. The predicted geometry from the simulation aligns with postoperative photographs. Simulations exploring the flap design parameters show variation in the tension. Lower tensions were achieved when rotation was oriented with respect to skin tension lines (horizontal tissue fibers) and smaller rotation angles. Conclusions: Tension distribution following rotation of scalp flaps can be predicted through personalized FE simulations. Flaps can be designed to reduce tension using FE, which may greatly improve the reliability of scalp reconstruction in craniofacial surgery, critical in complex cases when scalp reconstruction is essential for coverage of hardware, implants, and/or bone graft.

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“…Third, the strain damage thresholds (above 75% and above 45%) reported in the literature for tissue injury (motivated by the work of (Ceelen et al, 2008;Loerakker et al, 2011) come from animal models and should be considered with some caution since they might not be relevant for humans. Very recently, in an attempt to elucidate the soft tissue injuries leading from pressure-driven ischemia, a computational model linking microvascular collapse to tissue hypoxia in a multiscale model of pressure ulcer initiation has been proposed (Sree et al, 2019a(Sree et al, , 2019b in the context of pressure ulcer formation. These types of models, coupled with recent improvements in ultrasound imaging technologies that allow to measure tissue perfusion in clinical routine, constitute opportunities for elucidating some of the scientific challenges associated with the customization of the injury thresholds.…”

Section: Discussionmentioning

confidence: 99%

Is a simplified Finite Element model of the gluteus region able to capture the mechanical response of the internal soft tissues under compression?

Macron

Pillet

Doridam

et al. 2020

Clinical Biomechanics

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Background: Internal soft tissue strains have been shown to be one of the main factors responsible for the onset of Pressure Ulcers and to be representative of its risk of development. However, the estimation of this parameter using Finite Element (FE) analysis in clinical setups is currently hindered by costly acquisition, reconstruction and computation times. Ultrasound (US) imaging is a promising candidate for the clinical assessment of both morphological and material parameters. Method: The aim of this study was to investigate the ability of a local FE model of the region beneath the ischium with a limited number of parameters to capture the internal response of the gluteus region predicted by a complete 3D FE model. 26 local FE models were developed, and their predictions were compared to those of the patient-specific reference FE models in sitting position. Findings: A high correlation was observed (R= 0.90, p-value < 0.01). A sensitivity analysis showed that the most influent parameters were the mechanical behaviour of the muscle tissues, the ischium morphology and the external mechanical loading. Interpretation: Given the progress of US for capturing both morphological and material parameters, these results are promising because they open up the possibility to use personalised simplified FE models for risk estimation in daily clinical routine.

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Linking microvascular collapse to tissue hypoxia in a multiscale model of pressure ulcer initiation

Cited by 23 publications

References 88 publications

Changes in the three-dimensional microscale topography of human skin with aging impact its mechanical and tribological behavior

Changes in the three-dimensional microscale topography of human skin with aging impact its mechanical and tribological behavior

Personalized Computational Models of Tissue-Rearrangement in the Scalp Predict the Mechanical Stress Signature of Rotation Flaps

Is a simplified Finite Element model of the gluteus region able to capture the mechanical response of the internal soft tissues under compression?

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