Advertisement

Quantifying the in vivo quasi-static response to loading of sub-dermal tissues in the human buttock using magnetic resonance imaging

      Highlights

      • Gluteal tissue deformation under a range of loads were measured for a diverse cohort using MRI scans.
      • Muscles deformed throughout the transition from weight-bearing to non-weight-bearing conditions.
      • Subcutaneous fat deformed little beyond the partial-weight-bearing condition.

      Abstract

      Background

      The design of seating systems to improve comfort and reduce injury would benefit from improved understanding of the deformation and strain patterns in soft tissues, particularly in the gluteal region.

      Methods

      Ten healthy men were positioned in a semi-recumbent posture while their pelvic and thigh region was scanned using a wide-bore magnetic resonance imaging (MRI) scanner. Independent measurements of deformation for muscles and fat were taken for the transition from non-weight-bearing to weight-bearing loads in three stages. A weight-bearing load was achieved through having the subject supported by a flat, rigid surface. A non-weight-bearing condition was achieved by removing the support under the left buttock, leaving all soft tissue layers undeformed. An intermediate condition partially relieved the subject's left buttock by lowering the support relative to the pelvis by 20 mm, which left the buttock partially deformed. For each of these conditions, the thicknesses of muscle and fat tissues below the ischial tuberosity and the greater trochanter were measured from the MRI data.

      Findings

      In this dataset, the greatest soft tissue deformation took place below the ischial tuberosity, with muscles (mean = 17.7 mm, SD = 4.8 mm) deforming more than fat tissues (mean = 4.3 mm, SD = 5.6 mm). Muscles deformed through both steps of the transition from weight-bearing to non-weight-bearing conditions, while subcutaneous fat deformed little after the first transition from non-weight-bearing to partial-weight-bearing. High inter-subject variability in muscle and fat tissue strains was observed.

      Interpretation

      Our findings highlight the importance of considering inter-subject variability when designing seating systems.

      Keywords

      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'

      Subscribe:

      Subscribe to Clinical Biomechanics
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect

      References

        • Al-Dirini R.M.
        • Reed M.P.
        • Thewlis D.
        Deformation of the gluteal soft tissues during sitting.
        Clin. Biomech. 2015;
        • Brienza D.
        • Vallely J.
        • Karg P.
        • Akins J.
        • Gefen A.
        An MRI investigation of the effects of user anatomy and wheelchair cushion type on tissue deformation.
        J. Tissue Viability. 2017;
        • Call E.
        • Hetzel T.
        • McLean C.
        • Burton J.N.
        • Oberg C.
        Off loading wheelchair cushion provides best case reduction in tissue deformation as indicated by MRI.
        J. Tissue Viability. 2017;
        • Dunk N.M.
        • Callaghan J.P.
        Gender-based differences in postural responses to seated exposures.
        Clin. Biomech. 2005;
        • Gefen A.
        How much time does it take to get a pressure ulcer? Integrated evidence from human, animal, and in vitro studies.
        Ostomy wound Manage. 2008; : 54(10)
        • Gefen A.
        The compression intensity index: a practical anatomical estimate of the biomechanical risk for a deep tissue injury.
        Technol. Health Care. 2008; 16: 141-149
        • Gefen A.
        Usage of anthropometry to determine etiological and risk factors in deep-tissue injury.
        in: Handbook of Anthropometry. Springer, 2012: 2443-2457
        • Kaplan R.J.
        Physical Medicine and Rehabilitation: Pearls of Wisdom.
        Boston Medical Publishing, 2003
        • Krouskop T.
        • Dougherty D.
        • Vinson F.
        A pulsed Doppler ultrasonic system for making noninvasive measurements of the mechanical properties of soft tissue.
        J. Rehabil. Res. Dev. 1987; 24: 1-8
        • Linder-Ganz E.
        • Gefen A.
        Mechanical compression-induced pressure sores in rat hindlimb: muscle stiffness, histology, and computational models.
        J. Appl. Physiol. 2004; 96: 2034-2049
        • Linder-Ganz E.
        • Gefen A.
        The effects of pressure and shear on capillary closure in the microstructure of skeletal muscles.
        Ann. Biomed. Eng. 2007; 35: 2095-2107
        • Linder-Ganz E.
        • et al.
        Pressure–time cell death threshold for albino rat skeletal muscles as related to pressure sore biomechanics.
        J. Biomech. 2006; 39: 2725-2732
        • Linder-Ganz E.
        • et al.
        Assessment of mechanical conditions in sub-dermal tissues during sitting: a combined experimental-MRI and finite element approach.
        J. Biomech. 2007; 40: 1443-1454
        • Linder-Ganz E.
        • et al.
        Real-time finite element monitoring of sub-dermal tissue stresses in individuals with spinal cord injury: toward prevention of pressure ulcers.
        Ann. Biomed. Eng. 2009; 37: 387-400
        • Makhsous M.
        • Lin F.
        A finite-element biomechanical model for evaluating buttock tissue loads in seated individuals with spinal cord injury.
        in: Bioengineering Research of Chronic Wounds. Springer, 2009: 181-205
        • Makhsous M.
        • et al.
        Finite element analysis for evaluation of pressure ulcer on the buttock: development and validation.
        IEEE Trans. Neural Syst. Rehabil. Eng. 2007; 15: 517-525
        • Makhsous M.
        • et al.
        Investigation of soft-tissue stiffness alteration in denervated human tissue using an ultrasound indentation system.
        J. Spinal Cord Med. 2008; 31: 88-96
        • Makhsous M.
        • et al.
        Use of MRI images to measure tissue thickness over the ischial tuberosity at different hip flexion.
        Clin. Anat. 2011; 24: 638-645
        • Mehta C.
        • Tewari V.
        Seating discomfort for tractor operators - a critical review.
        Int. J. Ind. Ergon. 2000; 25: 661-674
        • Salcido R.
        • Popescu A.
        • Ahn C.
        Animal models in pressure ulcer research.
        J. Spinal Cord Med. 2007; 30: 107-116
        • Shabshin N.
        • et al.
        Use of weight-bearing MRI for evaluating wheelchair cushions based on internal soft-tissue deformations under ischial tuberosities.
        J. Rehabil. Res. Dev. 2010; 47: 31-42
        • Silber G.
        • Then C.
        Preventive Biomechanics.
        Springer, 2013
        • Silber G.
        • Then C.
        Human body models: boss-models.
        in: Preventive Biomechanics. Springer, 2013: 175-244
        • Sonenblum S.E.
        • et al.
        3-dimensional buttocks response to sitting: a case report.
        J. Tissue Viability. 2013; 22: 12-18
        • Sonenblum S.E.
        • Sprigle S.H.
        • Cathcart J.M.
        • Winder R.J.
        3D anatomy and deformation of the seated buttocks.
        J. Tissue Viability. 2015; 24: 51-61
        • Stockton L.
        • Parker D.
        Pressure relief behaviour and the prevention of pressure ulcers in wheelchair users in the community.
        J. Tissue Viability. 2002; 12 (88-90): 84
        • Then C.
        • et al.
        A method for a mechanical characterisation of human gluteal tissue.
        Technol. Health Care. 2007; 15: 385-398
        • Then C.
        • Vogl T.
        • Silber G.
        Method for characterizing viscoelasticity of human gluteal tissue.
        J. Biomech. 2012; 45: 1252-1258
        • Todd B.A.
        • Thacker J.G.
        Three-dimensional computer model of the human buttocks, in vivo.
        J. Rehabil. Res. Dev. 1994; 31: 111
        • Untaroiu C.D.
        • Lu Y.-C.
        Material characterization of liver parenchyma using specimen-specific finite element models.
        J. Mech. Behav. Biomed. Mater. 2013; 26: 11-22
        • Untaroiu C.
        • et al.
        Characterization of the lower limb soft tissues in pedestrian finite element models.
        in: 19th International Technical Conference on the Enhanced Safety of Vehicles. 2005
        • Van Loocke M.
        • Lyons C.
        • Simms C.
        Viscoelastic properties of passive skeletal muscle in compression: stress-relaxation behaviour and constitutive modelling.
        J. Biomech. 2008; 41: 1555-1566
        • Van Loocke M.
        • Simms C.
        • Lyons C.
        Viscoelastic properties of passive skeletal muscle in compression—cyclic behaviour.
        J. Biomech. 2009; 42: 1038-1048
        • Vannah W.M.
        • Childress D.S.
        Indentor tests and finite element modeling of bulk muscular tissue in vivo.
        J. Rehabil. Res. Dev. 1996; 33: 239-252
        • Wall J.
        Preventing pressure sores among wheelchair users.
        Prof. Nurse. 2000; 15: 321-324