@prefix vivo: . @prefix edm: . @prefix ns0: . @prefix dcterms: . @prefix skos: . vivo:departmentOrSchool "Applied Science, Faculty of"@en, "Mechanical Engineering, Department of"@en ; edm:dataProvider "DSpace"@en ; ns0:degreeCampus "UBCV"@en ; dcterms:creator "Callaghan, Stephen Francis Paul"@en ; dcterms:issued "2010-08-27T16:54:04Z"@en, "1989"@en ; vivo:relatedDegree "Master of Applied Science - MASc"@en ; ns0:degreeGrantor "University of British Columbia"@en ; dcterms:description """The introduction of the pneumatic tourniquet has greatly facilitated orthopedic limb surgery. However, the use of this occlusive device is still associated with recurring cutaneous, vascular and neuromuscular injuries. The present research investigates the transmission of pressure from the pneumatic tourniquet to the underlying limb in order to isolate and perhaps minimize the destructive forces causing post-surgical injuries. A finite element analysis of the tourniquet/limb combination is performed for several patient and cuff parameters. In particular, the influence of cuff design features (such as cuff width and applied surface pressure profile) and patient features (such as arm radius and fat content) on the levels of destructive forces is assessed. Additionally, the use of an Esmarch bandage together with a pneumatic tourniquet is investigated and compared to the conventional tourniquet configuration. Results from this numerical investigation suggest that high levels of shear and negative axial strain at the cuff edges may account for experimentally observed nerve damage. Furthermore, using wider cuffs which exhibit smooth surface pressure profiles may reduce the risk of post-operative tourniquet-induced nerve injuries. Larger limb radii and greater fat contents generate higher destructive strain levels. And finally, wrapping an Esmarch bandage around the limb at the cuff edges significantly reduces the levels of shear and negative axial strains experienced under occlusion conditions."""@en ; edm:aggregatedCHO "https://circle.library.ubc.ca/rest/handle/2429/27828?expand=metadata"@en ; skos:note "A BIOMECHANICAL ANALYSIS OF LIMB COMPRESSION INDUCED BY PNEUMATIC SURGICAL TOURNIQUETS By Stephen Francis Paul Callaghan B. A. Sc., The University of Sherbrooke, 1987 A T H E S I S S U B M I T T E D I N P A R T I A L F U L F I L L M E N T O F T H E R E Q U I R E M E N T S F O R T H E D E G R E E O F M A S T E R S O F A P P L I E D S C I E N C E in T H E F A C U L T Y O F G R A D U A T E S T U D I E S ( D E P A R T M E N T O F M E C H A N I C A L E N G I N E E R I N G ) We accept this thesis as conforming to the required standard T H E U N I V E R S I T Y O F B R I T I S H C O L U M B I A August 1989 © Stephen Francis Paul Callaghan, 1989 In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, I agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the head of my department or by his or her representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. (Department of Mechanical Engineering) The University of British Columbia 6224 Agricultural Road Vancouver, Canada V6T 1W5 Date: Abstract The introduction of the pneumatic tourniquet has greatly facilitated orthopedic limb surgery. However, the use of this occlusive device is still associated with recurring cuta-neous, vascular and neuromuscular injuries. The present research investigates the trans-mission of pressure from the pneumatic tourniquet to the underlying limb in order to isolate and perhaps minimize the destructive forces causing post-surgical injuries. A finite element analysis of the tourniquet/limb combination is performed for several patient and cuff parameters. In particular, the influence of cuff design features (such as cuff width and applied surface pressure profile) and patient features (such as arm radius and fat content) on the levels of destructive forces is assessed. Additionally, the use of an Esmarch bandage together with a pneumatic tourniquet is investigated and compared to the conventional tourniquet configuration. Results from this numerical investigation suggest that high levels of shear and negative axial strain at the cuff edges may account for experimentally observed nerve damage. Furthermore, using wider cuffs which exhibit smooth surface pressure profiles may reduce the risk of post-operative tourniquet-induced nerve injuries. Larger limb radii and greater fat contents generate higher destructive strain levels. And finally, wrapping an Esmarch bandage around the limb at the cuff edges significantly reduces the levels of shear and negative axial strains experienced under occlusion conditions. 11 Table of Contents Abstract ii List of Tables viii List of Figures ix Nomenclature xvii Terminology xx Acknowledgement xxiv 1 INTRODUCTION 1 1.1 Historical Evolution of the Tourniquet 2 1.2 Injuries Caused by the Use of Pneumatic Tourniquets 4 1.3 Problem Definition 6 1.3.1 Research Objectives 7 2 REVIEW OF LITERATURE 10 2.1 Studies Investigating Pressure Profiles in Soft Tissue . 11 2.1.1 Studies Using Artificial Limb Models 11 2.1.2 Studies Using Animals 13 2.1.3 Studies Using Cadavers 14 2.1.4 Studies Using Humans 16 2.1.5 Auerbach's Finite Element Model . 17 iii 2.1.6 Hodgson's Analytical Model 19 2.2 Studies Investigating the Mechanisms of Nerve Damage 21 2.2.1 Evidence Supporting the Theory of Ischemia 21 2.2.2 Evidence Supporting the Theory of Mechanical Damage 23 2.2.2.1 Ochoa's Proposed Mechanism of Mechanical Damage . . 25 3 DEFINITION OF MODEL PARAMETERS 26 3.1 Mechanical Properties of Biological Tissue 27 3.1.1 Mechanical Behaviour of Muscle Tissue 28 3.1.2 Mechanical Properties of Blood Vessels 32 3.1.3 Mechanical Properties of Bone 35 3.2 Interactions at the Boundaries 36 3.2.1 Bone/Muscle Interface 36 3.2.2 Skin/Tourniquet Interface 37 3.2.3 Axial Constraint of the Limb Model Ends 38 3.3 Surface Pressure Distribution under the Tourniquet 38 3.3.1 Previous Experimental Results 39 3.3.2 Mathematical Characterization of the Surface Pressure Distribution 40 3.4 Blood Flow Occlusion 42 3.4.1 Experimental Investigations of Blood Flow Occlusion 43 3.4.2 Analytical and Numerical Modelling of Blood Flow Occlusion . . 45 4 FINITE ELEMENT MODELS 48 4.1 Finite Element Method 49 4.1.1 Basic Theory Behind the Finite Element Method 50 4.1.2 Applications of the Finite Element Method to Biological Structures 51 4.2 Model Assumptions 52 iv 4.2.1 Assumptions Pertaining to the Limb 52 4.2.1.1 Assumptions Pertaining to the Limb Structure 53 4.2.1.2 Assumptions Pertaining to the Limb Geometry 54 4.2.2 Assumptions Pertaining to the Main Artery of the Limb 55 4.2.3 Assumptions Pertaining to Loading Conditions 56 4.3 Soft Tissue Compression Models 57 4.3.1 Single-Layer Limb Model 58 4.3.2 Multi-Layer Limb Model 59 4.4 Blood Vessel Occlusion Model 60 5 RESULTS AND DISCUSSION 62 5.1 Comparison of the Finite Element Models with Previous Models 64 5.1.1 Thick-Walled Cylinder Theory 64 5.1.2 Auerbach's Finite Element Model 66 5.1.3 Hodgson's Analytical Model 68 5.1.4 Thomson's and Doupe's Experimental Results 69 5.2 Identification of the Destructive Stress(es) or Strain(s) 70 5.3 Influence of Cuff and Patient Parameters 72 5.3.1 Influence of Boundary Condition Settings 74 5.3.1.1 Bone/Muscle Interface 75 5.3.1.2 Skin/Cuff Interface 75 5.3.1.3 Axial Ends of the Model . 76 5.3.2 Influence of Cuff Width 76 5.3.3 Influence of Surface Pressure Profile 78 5.3.3.1 Variable Parameters of the Sinusoidal Pressure Profile . 81 5.3.4 Influence of Limb Radius 81 v 5.3.5 Influence of Fat Content 83 5.4 Improved Cuff Design 85 5.4.1 Combined Use of the Esmarch Bandage and the Tourniquet Cuff . 85 5.4.1.1 Esmarch/tourniquet Overlap 86 5.4.1.2 Esmarch Relative Pressure . 87 5.4.1.3 Esmarch Width 87 5.4.1.4 Discussion 88 5.5 Results from the Blood Vessel Occlusion Model 89 6 CONCLUSIONS AND RECOMMENDATIONS 92 6.1 Conclusions 92 6.1.1 General Conclusions Resulting from the Present Research 93 6.1.2 Specific Conclusions Resulting from the Present Research 94 6.2 Recommendations 97 6.2.1 Recommendations for Clinical Use 97 6.2.2 Recommendations for Future Cuff Designs 98 6.3 Recommendations for Further Investigations 98 6.3.1 Clinical and Experimental Investigations 99 6.3.2 Numerical and Analytical Investigations 100 Bibliography cii Appendices 222 A NERVE ANATOMY 222 B FINITE ELEMENT THEORY 224 vi C ANSYS PROGRAM LISTINGS D THICK-WALLED CYLINDER THEORY E LIMB COMPRESSION MODEL SIMULATIONS vii List of Tables 3.1 Mechanical properties of muscles 108 3.2 Mechanical properties of blood vessels 109 3.3 Mechanical properties of bone 110 5.1 Model properties used for the thick-walled cylinder analysis I l l 5.2 Model properties used for replicating Hodgson's model 112 5.3 Model properties of the-artery compression model 113 E . l Code name nomenclature 256 . E.2 Cuff width vs l imb radius (HON k NON) 258 E.3 Cuff width vs pressure profile (HON & NON) . 259 E.4 L imb radius vs pressure profile (HON & N O N ) 260 E.5 Offset vs peaks (HON & NON) 261 E.6 Cuff width vs fat content (NON) 262 E.7 Fat content vs l imb radius (NON) 263 E.8 Fat content vs pressure profile (NON) 264 E.9 Boundary conditions (HON & NON) 265 E.10 Esmarch overlap vs Esmarch width (HOE & NOE ) 266 E . l l Esmarch overlap vs Esmarch pressure (HOE & NOE ) 267 E.12 Esmarch width vs Esmarch pressure (HOE & NOE ) 268 Vlll List of Figures 2.1 Limb cross-sections 114 2.2 Griffiths' and Heywood's models 115 2.3 Griffiths' and Heywood's models subjected to a twisting force 115 2.4 McLaren's and Rorabeck's experiments 116 2.5 Pressure profiles recorded by McLaren and Rorabeck 117 2.6 Surface pressure profiles for the pneumatic tourniquet and the Esmarch bandage 117 2.7 Pressure probe used by Shaw and Murray 118 2.8 Shaw's and Murray's experimental setup 119 2.9 Nomogram relating leg circumference, tissue pressure and tourniquet pres-sure 120 2.10 Relationship between leg circumference and average tissue pressure . . . 120 2.11 Pressure probe used by Breault 121 2.12 Breault's experimental setup 122 2.13 Thomson's and Doupe's experimental results 123 2.14 Effect of cuff width on recorded arterial pressure 123 2.15 Auerbach's finite element mesh of the analyzed limb section . 124 2.16 Hydrostatic pressure distribution numerically evaluated by Auerbach com-pared to Thomson's and Doupe's experimental results 125 2.17 Octahedral shear stress profiles as computed by Auerbach 126 ix 2.18 Hydrostatic pressure distribution analytically calculated by Hodgson com-pared to Thomson's and Doupe's experimental results 127 2.19 Invagination phenomenon observed by Ochoa et al 128 2.20 Direction of displacement of the nodes of Ranvier with respect to cuff position 129 2.21 Histogram illustrating the distribution of nerve lesions relative to cuff site 129 3.1 Hill's three element muscle model 130 3.2 Stress-strain curves for three muscle samples 130 3.3 Stress-strain curves for different human squeletal muscles 131 3.4 Stress-strain curves for elastin and collagen 131 3.5 Setup to load arteries in axial tension and internal compression . . . . . 132 3.6 Material properties of a human brachial artery 132 3.7 Stress-strain curves for arteries 133 3.8 Collapsing process . . . 134 3.9 Cross-sections 135 3.10 Area-perimeter relationship for latex tubes and arteries 135 3.11 Limb model showing the three main boundaries 136 3.12 Experimental parabolic surface pressure profile measured by Breault . . . 137 3.13 Three-dimensional view of the surface pressure profile under a pneumatic tourniquet 137 3.14 Hodgson's surface pressure profiles 138 3.15 Comparison between smooth and discretized surface pressure profiles . . 139 3.16 Three main pressure profiles applied to the limb model 140 3.17 Varying offset and multiple peak characteristics of the sinusoidal pressure profile 141 3.18 Setup to simulate blood flow through the arteries 142 x 3.19 Experimental results of occlusion pressure vs the ratio of cuff width to arm circumference 143 3.20 Results from beam model simulation of artery collapse 143 4.1 Steps performed to obtain the limb compression model 144 4.2 Muscle structure 145 4.3 Finite element models of an axisymmetric limb 146 4.4 Loading conditions imposed 147 4.5 Boundary conditions as applicable to the limb compression model . . . . 148 4.6 Boundary conditions as applicable to the artery model 149 4.7 Single-layer limb compression model 150 4.8 Multi-layer limb compression model 151 4.9 Full section of the finite element artery model 152 4.10 Quarter section of the finite element artery model 153 5.1 Single-layer finite element limb compression model subjected to thick-walled cylinder conditions 154 5.2 Influence of radial mesh on the model's accuracy (absolute average per-centage difference) 155 5.3 Influence of radial mesh on the model's accuracy (maximum percentage difference 155 5.4 Influence of axial mesh on the model's accuracy (absolute average percent-age difference) 156 5.5 Influence of axial mesh on the model's accuracy (maximum percentage difference) 156 5.6 Comparison of stress profiles for varying Ez 157 5.7 Comparison of stress profiles for varying urz and ugz 158 5.8 Radial stress profiles for varying urg 159 xi 5.9 Circumferential stress profiles for varying uTe 160 5.10 Hydrostatic pressure distributions (14 elements) 161 5.11 Hydrostatic pressure distributions (24 elements) 162 5.12 Axial strain distributions for a sinusoidal surface pressure profile 163 5.13 Axial strain distributions for a rectangular surface pressure profile . . . . 163 5.14 Axial strain distributions when the smallest arm radius considered in Hodgson's study is assumed 164 5.15 Axial strain distributions when the largest arm radius considered in Hodg-son's study is assumed 164 5.16 Comparison of the maximum relative pressure at the bone level 165 5.17 Comparison of the width of the 100% pressure zone at the bone 165 5.18 Component stress profiles 166 5.19 Principal stress profiles 167 5.20 Combination stress profiles 168 5.21 Component strain profiles 169 5.22 Predicted axial strain profiles for varying boundary condition setting at each nerve location (single-layer model) 170 5.23 Predicted shear strain profiles for varying boundary condition setting at each nerve location (single-layer model) 171 5.24 Predicted axial strain profiles for varying cuff width (single-layer model) . 172 5.25 Predicted shear strain profiles for varying cuff width (single-layer model) 173 5.26 Predicted axial strain profiles for varying cuff width at each nerve location (single-layer model) 174 5.27 Predicted shear strain profiles for varying cuff width at each nerve location (single-layer model) 175 5.28 Maximum axial strain intensities for varying cuff width 176 xii 5.29 Maximum shear strain intensities for varying cuff width 177 5.30 Average maximum axial strain intensities for varying cuff width and limb radius 178 5.31 Average maximum shear strain intensities for varying cuff width and limb radius 179 5.32 Predicted axial strain profiles for varying surface pressure profile (single-layer model) 180 5.33 Predicted shear strain profiles for varying surface pressure profile (single-layer model) 181 5.34 Predicted axial strain profiles for varying surface pressure profile at each nerve location (single-layer model) 182 5.35 Predicted shear strain profiles for varying surface pressure profiles at each nerve location (single-layer model) 183 5.36 Maximum axial strain intensities for varying surface pressure distribution 184 5.37 Maximum shear strain intensities for varying surface pressure distribution 185 5.38 Average maximum axial strain intensities for varying surface pressure dis-tribution and cuff width 186 5.39 Average maximum shear strain intensities for varying surface pressure dis-tribution and cuff width 187 5.40 Average maximum axial strain intensities for varying surface pressure dis-tribution and limb radius 188 5.41 Average maximum shear strain intensities for varying surface pressure dis-tribution and limb radius 189 5.42 Average maximum strain intensities for varying surface pressure distribu-tion and fat content (multi-layer model) 190 X l l l 5.43 Average maximum axial strain intensities for varying pressure offset (si-nusoidal pressure distribution) 191 5.44 Average maximum shear strain intensities for varying pressure offset (si-nusoidal pressure distribution) 192 5.45 Predicted axial strain profiles for varying limb radius (single-layer model) 193 5.46 Predicted shear strain profiles for varying limb radius (single-layer model) 194 5.47 Predicted axial strain profiles for varying limb radius at each nerve location (single-layer model) 195 5.48 Predicted shear strain profiles for varying limb radius at each nerve loca-tion (single-layer model) 196 5.49 Maximum axial strain intensities for varying limb radius 197 5.50 Maximum shear strain intensities for varying limb radius 198 5.51 Average maximum axial strain intensities for varying limb radius and cuff width 199 5.52 Average maximum shear strain intensities for varying limb radius and cuff width 200 5.53 Predicted axial strain profiles for varying fat content at each nerve location (multi-layer model) 201 5.54 Predicted shear strain profiles for varying fat content at each nerve location (multi-layer model) 202 5.55 Maximum axial strain intensities for varying fat content (multi-layer model)203 5.56 Maximum shear strain intensities for varying fat content (multi-layer model)203 5.57 Proposed Esmarch/tourniquet combination and its resulting pressure profile204 5.58 Average maximum axial strain intensities for varying Esmarch overlap and width 205 xiv 5.59 Average maximum shear strain intensities for varying Esmarch overlap and width 206 5.60 Average maximum axial strain intensities for varying Esmarch overlap and cuff pressure 207 5.61 Average maximum shear strain intensities for varying Esmarch overlap and cuff pressure 208 5.62 Average maximum axial strain intensities for varying Esmarch width and cuff pressure 209 5.63 Average maximum shear strain intensities for varying Esmarch width and cuff pressure 210 5.64 Comparison of predicted axial strain profiles (single-layer model) 211 5.65 Comparison of predicted shear strain profiles (single-layer model) . . . . 212 5.66 Schematic representation of the pneumatic tourniquet as it is inflated . . 213 5.67 Load reduction induced by upward-curving of the cuff edges 214 5.68 Cross-section of the collapsed artery 215 5.69 Predicted occlusion pressures for varying cuff width and artery length . . 216 5.70 Predicted occlusion pressures for varying cuff width and ET . . . . . . . . 216 5.71 Predicted occlusion pressures for varying cuff width and E$ 217 5.72 Predicted occlusion pressures for varying cuff width and Ez 217 6.1 Proposed multi-bladder tourniquet 218 6.2 Proposed Esmarch/tourniquet configuration . 219 6.3 Examples of pressure sensors 220 6.4 Example of experimental setup to investigate blood flow occlusion . . . . 221 A.l Structural features of a peripheral nerve 222 A.2 General plan of a myelinated nerve fiber 223 xv B.l Single finite element 224 B.2 Simple two element structure 228 D.l Thick-walled cylinder under limb compression constraints 252 D.2 Free body diagram of a selected annulus 253 xvi Nomenclature a Inner radius of the cylinder (m) {a} Displacement vector (m) a. Displacements associated with node i (m) A Cross-section area of the artery (m2) Ao Initial cross-section area of the artery (m2) b Outer radius of the cylinder (m) CIRC Limb circumference (m) DOP Doppler occlusion pressure (Pa) error Average error (%) E Young's modulus (Pa) E r Radial Young's modulus (Pa) E z Axial Young's modulus (Pa) Eg Circumferential Young's modulus (Pa) {f }i Force vector of element i (N) {F} Body force vector of an element (N/m3) h Wall thickness of the vessel (m) I Moment of inertia (ro4) [k]j Stiffness matrix of element i (N/m) K Bulk modulus (Pa) [K] Global stiffness matrix of the structure (N/m) 1 Half-length of the artery section (m) MESH Number of elements in the axial or radial direction xvn n Number of lobes in the collapsed configuration N Number of peaks in the sinusoidal pressure distribution N i Linear shape functions associated with node i o E Esmarch overlap (%) O F F Pressure offset at the edges of the cuff (%) P Transmural pressure on the artery (Pa) Po Outer pressure on the cylinder (Pa) P d i a Diastolic pressure (Pa) P E Esmarch pressure (Pa) Pmax Maximum pressure at the center of the cuff (Pa) Pocc Occlusion pressure (Pa) P e ( z ) Exponential pressure distribution (Pa) P r ( z ) Rectangular pressure distribution (Pa) P s ( z ) Sinusoidal pressure distribution (Pa) P D Pressure distribution P E Potential energy (J) r Radial position (m) ro Outer radius of the artery (m) r D Bone radius (m) ri Limb radius (m) t Thickness of the element (m) {T} Traction force vector of an element (N/m) u Displacement in the x direction (m) U Strain energy of an element (J) V Displacement in the y direction (m) W Total energy of an element (J) xviii W E Esmarch width (m) W I D T H Cuff width (m) r Boundary of an element (m) Strain vector (m/m) e z Ax ia l strain (m/m) £e Circumferential strain (m/m) /z(z) Step function V Poisson ratio Poisson ratio from radial to axial direction vTe Poisson ratio from radial to circumferential direction Poisson ratio from circumferential to axial direction M Stress vector (Pa) Cr Octahedral shear stress (Pa) C h Hydrostatic pressure (Pa) o-n Principal stresses for n=l,2,3 (Pa) °~x Stress in the x direction (Pa) °y Stress in the y direction (Pa) 0\"i ,F.E. Stress at position i as determined by the finite element method (Pa) Oi. theo Stress at position i as determined by the thick-walled cylinder theory (Pa) M O Radia l stress distribution (Pa) cr2 > 3 > 3 > 3 > i .25 r - • ! >50 .75 RADIAL DIMENSION J 1.00 l z I 1 2 Figure 2.15: Auerbach's finite element mesh of the analyzed limb section [42] Figures 125 SK :N 100 .6b-, .30 14 too TOO •6 IOC 97 io: IOC 92 / ff it •' •0 «5 20 19 17 44 * s , o « > so IB 30 hi n 1 31 - 17 70/ 44 «, / 26 4 \\ * \\ / 1.2 1.0 89/ 59 SC 26 2S 13 19 2 1 v l 1 • PROXIMAL DISTANCE FROM CUFF EDGE p r e s s u r e v a l u e s r e l a t i v e t o c u f f p r e s s u r e (%) .4 O I S 7 A . . . 22N 22N 22N 22N 22N 22N 22N 22N 22N 22N 11N S K I N I.OO-RADIUS 6 5 -BONE .30-• • i 1 » i \\ i 1 2 7 8 7B 78 77 ; 77 77 77 79 7 6 / 1 \\ 41 ' 9 1i 11 8 -- 79 79 79 79 79 79 80 82 ) ,60 42 \\ 36 \\ 20 12 8 I 2 81 81 82 82 83 84 84 69' 1 / 54 54 \\ 39 \\ 18 9 7 1 t 8 7 89 91 94 98 100 85 ' / 67 57 46 \\ 25 9 6 4 I p r e s s u r e v a l u e s r e l a t i v e t o c u f f p r e s s u r e * (») i 14 I I I I 12 10 .8 6 .4 .2 0 PROXIMAL DISTANCE FROM CUFF EDGE DISTAL-Figure 2.16: Hydrostatic pressure distribution numerically evaluated by Auerbach compared to Thomson's and Doupe's experimental results [42] Figures 126 LEGEND * 1 ( r = 0.00 ) -• #2 (re 0 OB ) - A #3 ( r = 0.16 ) -- #4 (re 0 24 ) -+ *5 ( r = 0.32 ) II I\" /. /I c u f f edge r a d i i 0.25 0.20 — I — 0.15 •0.00 •0 05 g < z c o -0 10 -0.15 o u ffi o a 5 0.10 005 0.00 DISTANCE FROM CUFF EDGE LEGEND — #1 ( r = 0.00 ) -• #2 ( rrOOB) - A #3 (f = 016 ) •• C *4 IA w ez *-to a < < c o Ul X « Figure 2.17: Octahedral shear stress profiles as computed by Auerbach [42] Figures 127 Sr. N 100 •til .30 I O C too 1 0 0 • 6 I O C 9 7 to: IOC C O M / S O * 3 7» i f ; • 0 , «i 2 0 1 9 J ; • 4 T 9 / «/ •s / / / / 9? 69/ S S S C 1 0 » 3 sc « 5 C 3c \\ . • 4 * \\ * \" 3 0 * 31' 44 4 , 3 « 3 6 1 7 3 6 \\ 1 14 12 • PROXIMAL 1.0 41 2 S 13 1 9 ? i \\ i i -r T OlSTANCE FROM CUFF EDGE p r e s s u r e r e l a t i v e t o c u f f p r e s s u r e (%) 1 .4 D I S T A . . Z p r e s s u r e r a l t i v e t o c u f f p r e s s u r e (%) Figure 2.18: Hydrostatic pressure distribution analytically calculated by Hodgson compared to Thomson's and Doupe's experimental results [44] Figures 128 a. Normal node of Ranvier showing a nodal gap 1.2 fim wide b. Abnormal node of Ranvier, four days after compression, showing minimal invagination of the paranode on the left by the one on the right, with obliteration of the nodal gap c. Enlargement of b. showing a more detailed account of the invagination phenomenon Figure 2.19: Invagination phenomenon observed by Ochoa et al. [3] Figures 129 Proximal Distal Figure 2.20: Direction of displacement of the nodes of Ranvier with respect to cuff position [3] P r O K i m j l Cuff Ditial 1 H p e r c e n t a g e o f damaged 10 H n e r v e f i b e r s - o 5 c m 10 Figure 2.21: Histogram illustrating the distribution of nerve lesions relative to cuff site [3] Figures 130 SOTMM Elostic Element Parallel Elastic Element Figure 3.1: Hill's three element muscle model [48] 1-0 »2 1.4 1.6 1.8 Elongation (1/1.) Contractile Figure 3.2: Stress-strain curves for three muscle samples [47] Figures 131 g/mm' 0 10 20 30 40 50 60 70 80 90 100 Elongat ion Figure 3.3: Stress-strain curves for different human squeletal muscles [35] Stroin(X) Figure 3.4: Stress-strain curves for elastin and collagen [48] Figures 132 46cm LONG) Figure 3.5: Setup to load arteries in axial tension and internal compression [51] Figure 3.6: Material properties of a human brachial artery [51] Brachial artery P°P*teal artery 0 20 40 60 80 100 120 Elongation ure 3.7: Stress-strain curves for arteries [35] Figures 134 a. For a latex tube b. For a vein Figure 3.8: Collapsing process [53] Figures 135 a. Of a collapsing latex tube b. Of a collapsing vein Figure 3.9: Cross-sections [53] e I D 1 I D i 1 . 1 f ! as o 1ft 1 -X / X r ^ T * \" i i i t - I . D A-T- ~ A J «* A - A 0 ' - D A D as \" «VEIN \" * LATEX TLI5E Figure 3.10: Area-perimeter relationship for latex tubes and arteries [53] Figure 3.11: Limb model showing the three main boundaries # Sensor Contact Figure 3.12: Experimental parabolic surface pressure profile measured by Breault [40] Figure 3.13: Three-dimensional view of the surface pressure profile under a pneumatic tourniquet [40] Figures 1.2 0.2 i . , 0 1 0.4 0.6 Axial Distance from Tourniquet Center a. Sinusoidal 1.5 -0.6 I • \" 1 ' 0 0-2 0.4 0.6 A x i a l D i s t a n c e f r o m T o u r n i q u e t C e n t e r b. Rectangular Figure 3.14. Hodgson's surface pressure profiles [44] Figures 139 Figure 3.15: Comparison between smooth and discretized surface pressure profiles Figures 140 200 Model with Sinusoidal Pressure Distribution *»»xow*09« o l C u H P V — « j r o 100 -100 Percentage of Cuff Width Model with Exponential Pressure Distribution 200 * » r c o i r t o p » of Cutf Pr»«»ur» 100 -100 Percentage of Cuff Width Model with Rectangular Pressure Distribution 200 100 *»nmrtoQm o l C u W P V — o u r » 100 Percentage of Cuff Width Figure 3.16: Three main pressure profiles applied to the limb model Figures 141 Variations in Offset Pressure at the Edges OOP 0*0 Percentage of Cuff Width Variations in Number of Peaks Percentage of Cuff Width Figure 3.17: Varying offset and multiple peak characteristics of the sinusoidal pressure profile Figures 142 Figure 3.18: Setup to simulate blood flow through the arteries [67] i Figures 143 9 ° Y n O D D j B n • c9D am t?g*& • a • rib m 0 ' £ \" * ' 0.6 1 to ' 1 • A • A ' A ' l!» ' Xa/io = Width/Circumference Figure 3.19: Experimental results of occlusion pressure vs the ratio of cuff width to arm circumference [40] 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 O Experimental Data + Uniform O Cosine A linear X Taylor wlo V Taylor wl + A V A D + R • T T 25 i 20 24 Cuff Width (cm) Figure 3.20: Results from beam model simulation of artery collapse [40] Figures a. Schematic representation of a surgical tourniquet around a limb b. Three-dimensional simplification of the limb compression model C u f f ~~~~~~~~ i-ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ—ZZZZZZ I-=—muscle t i s s u e I I I I I Bone c. Axisymmetric view of the single-layer limb compression model C u f f ~ 1 ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ — - s k i n a t t y t i s s u e 1 1 1 1 1 1 1 1 1 1 1 1 [j muscle t i s s u e Bone \"\\ I — : - 1 d. Axisymmetric view of the multi-layer limb compression model Figure 4.1: Steps performed to obtain the limb compression model Figures 1 4 5 a. Schematic representation of a muscle • u s c W Fiber b. Example of the finite element structure of a muscle with the following mechanical properties: Er = E6 = 1 5 0 0 0 P o , Ez = xET = 0.5 Er = 7 5 0 0 Pa, vTl = v6z = 0.49, and Vrf = 0.45 Figure 4.2: Muscle structure Figures 146 Half Limb Length Half Cuff Width Limb Radius Bone Radius Median and Ulnar Nerves Musculocutaneous 'Nerve -Radial Nerve -Bone a. Geometric features of the single-layer limb compression model S k i n L a y e r a t t y T i s s u e L a y e r Median and Ulnar Nerves Musculocutaneous \"Nerve ^ R a d i a l Nerve -Bone b. Geometric features of the multi-layer limb compression model Figure 4.3: Finite element models of an axisymmetric limb a. Single-layer limb compression model with sinusoidal surface pressure distribution m u s c l e t i s s u e bone i b. Single-layer limb compression model with exponential surface pressure distribution p r e s s u r e p r o f i l e nil m u s c l e t i s s u e ^ ] bone I c. Single-layer limb compression model with rectangular surface pressure distribution Figure 4.4: Loading conditions imposed Figures 148 c u f f s o f t t i s s u e bone FFF FFR FRF FRR RFF RFR RRF RRR Figure 4.5: Boundary conditions as applicable to the limb compression model Figures 149 Figure 4.6: Boundary conditions as applicable to the artery model Figures 150 a x i s o f symmetry t h r o u g h c e n t e r o f c u f f c u f f r e s t r a i n e d s e t t i n g a t t h e s k i n / c u f f i n t e r f a c e * f « 1 * -r 0-r : i V • r l l BSJl w \"l.'J L. y 'i 1* w L i - l _ i . muscle t i s s u e bone r e s t r a i n e d s e t t i n g a t t h e bone/musQle i n t e r f a c e Figure 4.7: Single-layer limb compression model Figures 151 c u f f r e s t r a i n e d s e t t i n g a t t h e s k i n / c u f f s k i n s *j i ; b - - V -I N j l i - 1 j . - L ' \\ 1 \\ ' 1 ' \\ ! -3 I b free motion at bone/muscle i n t e r f a c e ) i ' . . • t, 11 V 1 *. 1 * t i i , ' 1 ' : 1 i ; • a X . Figure 5.1: Single-layer finite element limb compression model subjected to thick-walled cylinder conditions Figures 155 Origin At 8.8,8.8 b. Obtained with the finite element method Figure 5.8: Radial stress profiles for varying ive Figures -2.8BE3 6.BB 1 6 0 -4.B8E3 - • -E.BBE3 •• b -8.BBE3 •• -1.88E4 -• 2.BBE-2 4.BBE-2 Radial Position (n) Origin At 8.8,8.8 a. Obtained with the thick-walled cylinder theory u = 8.16 u : B.26 u = 8.38 u = 6.40 u = 8.49 -2.B8E3 8.66 -4.88E3 -6.6BE3 E.88E-2 b -8.86E3 CO -1.88E4 •• Radial Position (m) Origin At B.8,8.6 b. Obtained with the finite element method u 8.16 u 8.26 _ _ u B.3B m m m m u = 8.46 u - 8.49 Figure 5.9: Circumferential stress profiles for varying HALF CUFF WIDTH 1.00 0.30 0.00 a. Obtained by Auerbach 78 78 | 78 I 77 n 77 | 77 I 79 79 | 41 9 I 11 11 1 8 79 79 | 79 I 79 79 79 | 80 I 82 60 | 42 36 | 20 12 | 8 81 81 | 82 I 82 83 84 | 84 I 69 54 | 54 39 | 18 9 I 7 87 89 | 91 I 94 98 100| 85 I 67 57 | 46 I 25 I 9 6 I 4 BONE HALF CUFF WIDTH 1.00 0.30 0.00 b. Obtained by ANSYS 71 1 71 | 70 1 70 | 69 | 69 | 68 | 66 | 62 | 46 | 21 | 6 3 I 1 74 | 74 | 73 1 73 1 72 70 | 68 | 64 | 58 I « | 28 | 15 9 I 6 80 | 80 | 80 1 79 1 78 76 | 73 | 68 | 60 | 48 | 33 | 22 16 I 14 92 | 92 | 92 1 92 1 93 92 | 89 | 83 | 71 I 55 | 39 | 25 23 | 38 BONE HALF CUFF WIDTH > 1.00 0.30 0.00 7 J 7 I 8 I 7 I 8 I 8 9 13 17 | 5 I 12 I 5 8 I 7 5 I 5 I 6 I 6 I 7 I 9 12 16 2 I 3 I 8 | 5 3 I 2 1 i 1 I 2 I 3 I 5 I 8 11 1 6 I 6 I 6 | * 7 I 7 5 i 3 I 1 I 2 I 5 I 8 * 16 14 I 9 I 14 | 16 17 I 34 BONE c. Difference between Auerbach and ANSYS Figure 5.10: Hydrostatic pressure distributions (14 elements) Figures H A L F C U F F WIDTH 1.00 0.30 78 | 78 | 78 | 77 | 77 | 77 | 77 79 | 79 | 41 | 9 | 11 11 I 8 79 | 79 | 79 | 79 | 79 | 79 | 80 82 60 | 42 | 36 | 20 12 I 8 81 | 81 | 82 | 82 | 83 | 84 | 84 69 54 | 54 | 39 | 18 9 I 7 87 | 89 | 91 | 94 | 98 | 100| 85 67 57 | 46 | 25 | 9 6 I 4 BONE 0.00 a. Obtained by Auerbach H A L F C U F F WIDTH 1.00 0.30 0.00 73 73 73 I 73 73 73 72 I 71 I 67 I 52 | 27 | 12 | 9 7 I 76 76 76 I 76 75 74 71 | 68 I 62 I 49 | 32 | 20 | 14 10 | 82 82 81 I 81 80 78 75 I 71 I 63 I 50 | 35 | 23 | 15 9 I 92 92 92 I 93 93 I 93 90 | 84 I 72 I 55 I 37 | 20 | 8 2 I BONE b. Obtained by ANSYS H A L F C U F F WIDTH 1.00 0.30 0.00 5 I 5 I 5 I 4 I 4 I * I 5 I & | 12 11 I 18 I 1 I 2 I 1 I 3 I 3 I 3 I 3 I « I 5 I 9 I 14 | 2 7 1 * I o I 2 I 2 I 1 I 1 I 1 I 1 I 3 I 6 I 9 I 2 I 9 4 1 4 | 5 I 6 I 2 I 5 I 3 I 1 I 1 I 5 I 7 I 5 I 17 | 15 9 I 12 | 11 I 2 I 2 I BONE c. Difference between Auerbach and ANSYS Figure 5.11: Hydrostatic pressure distributions (24 elements) Figures 163 1 . 8 b. Obtained by ANSYS Figure 5.12: Axial strain distributions for a sinusoidal surface pressure profile b. Obtained by ANSYS Figure 5.13: Axial strain distributions for a rectangular surface pressure profile Figures 164 °-l 0.2> j 0.3 0.4 0.5 a. Obtained by Hodgson maximum negative intensity zones b. Obtained by ANSYS Figure 5.14: Axial strain distributions when the smallest arm radius considered in Hodgson's study is assumed a. Obtained by Hodgson maximum negative intensity zones H i 1111 iijiyjHB IJ|pMjlll||||| | | | l l i p i | | l f l | l | i pWI|IIBffillll1ffllllllllH b. Obtained by ANSYS Figure 5.15: Axial strain distributions when the largest arm radius considered in Hodgson's study is assumed Figures 165 126.68 --C 88.88 - • 48.88 • • e.e I I 8.88 4.88 CUFF WIDTH (cn) 8.86 Origin At 8.8,8.8 I I I I 1 h 12.88 ie.ee 2e.ee Thonson and Doupe Finite Elenent (ANSYS) Figure 5.16. Comparison of the maximum relative pressure at the bone level o o 3 e.ee 8.66 4.88 CUFF WIDTH (cn) 8.88 12.88 IE.B8 26. Origin At 8.8,8.8 Thoison and Doupe Finite Eleaent (ANSYS) Figure 5.17: Comparison of the width of the 100% pressure zone at the bone i Figures 166 a. Radial stress ^-peak intensity zones b. Circumferential stress d. Shear stress Figure 5.18: Component stress profiles Figures C 167 c. Low intensity Figures 168 a. Hydrostatic Btress b. Octahedral stress Figure 5.20: Combination stress profiles Figures 169 b. Circumferential strain d. Shear strain Figure 5.21: Component strain profiles Figures a. Radial nerve s 2 AXIAL POSITION 170 i n d i c a t e s t h e edge o f t h e c u f f on e a c h c u r v e AXIAL POSITION b. Musculocutaneous nerve 1.Tt AXIAL POSITION c. Median/ulnar nerves Figure 5.22: Predicted axial strain profiles for varying boundary condition setting at each nerve location (single-layer model) Figures 171 \"{jur-i PXML POSITION frigln t t t.M.t a. Radial nerve i n d i c a t e s t h e edge o f t h e c u f f on e a c h c u r v e s 2 » AXIAL posmoN b. Musculocutaneous nerve I \\ ! \\ \\ KOfiL POSITION c. Median/ulnar nerves Figure 5.23: Predicted shear strain profiles for varying boundary condition setting at each nerve location (single-layer model) Figures 172 a. 5.0 cm cuff width b. 10.0 cm cuff width I > d. 20.0 cm cuff width Figure 5.24: Predicted axial strain profiles for varying cuff width (single-layer model) Figures 173 a. 5.0 cm cuff width rzz: > b. 10.0 cm cuff width d. 20.0 cm cuff width Figure 5.25: Predicted shear strain profiles for varying cuff width (single-layer model) Figures 174 AXIAL POSITION •r-lSin at t.1,1.1 a. Radial nerve ft.t CP CUFF If.1 CR CUFF 15.1 CR CUFF 2*.I CR CUFF indicates the edge of the cuff on each curve AXIAL POSITION b. Musculocutaneous nerve I.t CD OFT It.* CR CUFF IS.* CR CUFF n.t CD exrr AXIAL POSITION f C I CUFF 11.1 CR CUFF U.R CR CUFF ».« CD CUFF c. Median/ulnar nerves Figure 5.26: Predicted axial Btrain profiles for varying cuff width at each nerve location (single-layer model) Figures a. Radial nerve AXIAL POSITION •rigin ni •.•,«.• B.I CH CUTF U.I CT CUFF is.• oi tun CD CUFF 175 *: i n d i c a t e s t h e edge o f t h e c u f f on e a c h c u r v e AXIAL POSITION b. Musculocutaneous nerve ll. I c« O F F 15.1 Ol O F T n.» a i O F T 7 i WOflL POSITION c. Median/ulnar nerves I. I Ql CUTF II. I n CUFF ll.t CT CUFF a.t at CUFF Figure 5.27: Predicted shear 6train profiles for varying cuff width at each nerve location (single-layer model) Figures e.se .18 • • H 1 I h • I 1 1 1 1 r-4.88 8.88 12.88 16.68 .J8<86 -B.38 • • Origin At 8.8,8.8 a. Single-layer model CUFF WIDTH ( c m ) — RADIAL NERVE .... MUSCULO NERVE 8 MEDIAN/ULNAR NERVES 8.86 8.86 -8.28 •• -8.48 •• CUFF WIDTH (cm) Origin At 8.8,8.8 b. Multi-layer model RADIAL NERVE .... MUSCULO NERVE MEDIAN/ULNAR NERVES Figure 5.28: Maximum axial strain intensities for varying cuff width Figures e.eo -8.25 • --8.75 -• -1.25 •• -1.75 - • I I — *• •4.88.'' 8.88 12.88 18.88 28.88 CUFF WIDTH ( c m ) Origin fit 8.8,8.8 a. Single-layer model RADIAL NERVE .... MUSCULO NERVE MEDIAN/ULNAR NERVES 0 8 .25 - -DC •— CO -8.75 - --1.25 -• -1.75 •• I I I 1 i 1 1 I 8.80 12.88 16.00 CUFF WIDTH ( c m ) Origin At 8.8,8.0 b. Multi-layer model RADIAL NERVE .... MUSCULO NERVE MEDIAN/ULNAR NERVES Figure 5.29: Maximum shear strain intensities for varying cuff width Figures 178 -5.BBE-2 + CUFF WIDTH ( c m ) Origin At B.8,6.6 a. Single-layer model 38 m ARM 58 HH ARM 76 HH ARH 1 r— 6.SB 4.68 -5.88E-2 + -8.15 + I I I 1 1 I I 6.86 16.6 CUFF WIDTH ( c m ) Origin At 8.6,8.8 38 KH ARM • . . • 58 m ARH 78 m ARH b. Multi-layer model Figure 5.30: Average maximum axial strain intensities for varying cuff width and limb radius Figures 179 B . S B -8 .56 • • -1 .88 • • -1 .58 • • I I I h I I I 1 I iE.ee 28.88 CUFF WIDTH ( c m ) Origin At 8 . 8 , 8 . 8 a. Single-layer model 38 HN ARK . . . . 58 MN ARM 78 NR ARH -8 .58 • • -1 .58 • • -I 1 I 6.88 H 1— i6.ee H r-28.88 CUFF WIDTH ( C m ) Origin At 8.8,8.8 b. Multi-layer model 38 HN ARH .... 58 HN ARH 78 HN ARH Figure 5.31: Average maximum shear strain intensities for varying cuff width and limb radius ures -0.5 -0.4 -0.3 -0.2 -0.1 0.0 0.1 III 0.2 Sinusoidal pressure profile Exponential pressure profile Rectangular pressure profile ure 5.32: Predicted axial strain profiles for varying surface pressure profile (single-layer model) Figures 181 c. Rectangular pressure profile Figure 5.33: Predicted shear strain profiles for varying surface pressure profile (single-layer model) AXIAL POSITION tWSOIML P.O. E m M c r T i M . r.t. KCTMCULM f.t. b. Musculocutaneous nerve AXIAL POSITION t n u s a i M t p . o . BtntJCULM P.O. c. Median/ulnar nerves Figure 5.34: Predicted axial strain profiles for varying surface pressure profile at each nerve location (single-layer model) Figures 183 Figure 5.35: Predicted shear strain profiles for varying surface pressure profile at each nerve location single-layer model) Figures -B.26 • • -8.48 •• i.ee A Origin fit B.B,B.B a. Single-layer model — i — 2.88 A 3.88 DISTRIBUTION • • • • RftDISL NERVE • • • • MUSCULO NERVE A A A A MEDIAN/ULNAR NERVES 8. -8.28 - • B.48 •• ac co 2.80 —4-3.80 PRESSURE DISTRIBUTION Origin At 8.8,8.8 b. Multi-layer model • • • • RADIAL NERVE • • • • MUSCULO NERVE A A A A MEDIAN/ULNAR NERVES Figure 5.36: Maximum axial strain intensities for varying surface pressure distribution Figures 185 e. i .es 2.68 3.88 .58 -•• -1.58 •• -2.58 \" • P R E S S U R E D I S T R I B U T I O N Origin At 8.8,8.8 a. Single-layer model • • • • RADIAL NERVE • • • • MUSCULO NERVE A A A A MEDIAN/ULNAR NERVES 8 -8.58 - • -1.58 •• -2.58 \" • 1.88 P R E S S U R E D I S T R I B U T I O N • • • • RADIAL NERVE • • • • MUSCULO NERVE Origin At 8.8,8.8 A A A A MEDIAN/ULNAR NERVES b. Multi-layer model Figure 5.37: Maximum shear strain intensities for varying surface pressure distribution Figures 8. 6 -6.28 -• ce t— C O I I h 4.88 • I 6.88 I I I I — 12.86 ie.ee • I i 28.66 CUFF WIDTH ( c m ) Origin Rt 8.8,8.6 a. Single-layer model SINUSOIDAL P.O. .... EXPONENTIAL P.O. RECTANGULAR P.O. e. e -8.18 •• -8.38 -ce co -8.58 • -H 1 H 4.88 .86 I I 1 I 1 I 12.68 16.88 28.ee M*r CUFF WIDTH ( c m ) ,r Origin At 8.8,8.8 b. Multi-layer model SINUSOIDAL P.O. EXPONENTIAL P.O. RECTANGULAR P.P. Figure 5.38: Average maximum axial strain intensities for varying surface pressure distribution and cuff width Figures i 12.86 1 — 16.88 4.88 .88 28.88 -2.58 -• CUFF WIDTH ( c m ) Origin Rt 8.8,8.8 a. Single-layer model SINUSOIDAL P.D. . . . . EXPONENTIAL P.D. RECTANGULAR P.D. H 1 1 H I I 12.88 -B.58 • --1.58 --2.5B •• 4.66 H r— 18.88 I I 28.ee CUFF WIDTH ( c m ) Origin At 8.8,8.8 b. Multi-layer model /f — SINUSOIDAL P.O. .... EXPONENTIAL P.D. RECTANGULAR P.D. Figure 5.39: Average maximum shear strain intensities for varying surface pressure distribution and cuff width Figures B.eo ^ -8.38 + CO 2e.ee 4e.ee 68.00 188 ARM RADIUS (mm) Origin Rt 6.0,6.0 a. Single-layer model SINUSOIDAL P.O. EXPONENTIAL P.D. RECTANGULAR P.D. 1 h 6e.ee e. -6.28 + -8.48 + 28.88 ARM RADIUS (mm) — — - SINUSOIDAL P.D. m m m a EXPONENTIAL P.D. Origin At 8.8,8.8 RECTANGULAR P.D. b. Multi-layer model Figure 5 40 Average maximum axial strain intensities for varying surface pressure distribution and limb radius Figures e.ee - I I I I I I I G. 8 28.BB 19.BB BB.88 -1.BB •- FtT II I FtT IS 1 FtT 2t t FtT • n ' ' • • vim _ 1 AXIAL POSITION •rlaln tt ! . « , • . • I X FtT a t FtT IS Z FAT n t FtT c. Median/ulnar nerves Figure 5.53: Pre d i c t e d axial strain profiles for varying fat content at each nerve location (multi-layer model) Figures 202 AXIAL POSITION S Z FBT 11 Z FAT 15 t FBT n i FAT a. Radial nerve indicates the edge of the cuff on each curve AXIAL POSITION •Main tt B I FBT 1« Z FAT 18 1 FBI 29 Z FBI b. Musculocutaneous nerve AXIAL POSITION •nam M B Z FAT U Z FBI IB Z FAT n t FBI c. Median/ulnar nerves Figure 5.54: Predicted shear strain profiles for varying fat content at each nerve location (multi-layer model) Figures i i i 1 i i i i e. e .ee 12.86 16.88 26.88 -8.26 - • B.«B • • FAT •/. — RADIAL NERVE . . . . MUSCULO NERVE Origin Rt 6 . 8 , 6 . 8 MEDIAN/ULNAR NERVES Figure 5.55: Maximum axial strain intensities for varying fat content (multi-layer model) -8.25 • • - 6 . 7 5 • • 2 -1.25 t co -1.75 • • -I 1 I I I I I 1 1 I 4.86 8.68 12.86 16.86 28.88 FAT 7. — — RADIAL NERVE m m m m MUSCULO NERVE Origin At 8 . 8 , 8 . 6 MEDIAN/ULNAR NERVES Figure 5.56: Maximum shear strain intensities for varying fat content (multi-layer model) Figures 204 r e s u l t i n g pressure p r o f i l e ~Eu7F :«- Esmarch •3 w. s o f t t i s s u e • • • ' • bone Figure 5.57: Proposed Esmarch/tourniquet combination and its resulting pressure profile Figures -e.u •--e.17 •• e.59 i.e .22 -ESMARCH OVERLAP Origin Rt 6.6,8.6 a. Single-layer model 26 HR ESHARCH . . . 36 HH ESHARCH .... 48 HH ESHARCH 56 HH ESHARCH 205 6 .12 • • -6.17 - • i.ee .22 — ESMARCH OVERLAP Origin Rt 8.6,6.0 b. Multi-layer model 26 HH ESHARCH _ _ . 39 HH ESHARCH • m m m 48 HH ESHARCH 56 HH ESHARCH Figure 5.58: Average maximum axial strain intensities for varying Esmarch overlap and width Figures my m 38 HH ESHARCH _ _ _ . 48 HH ESHARCH 56 HH ESHARCH Figure 5.59: Average maximum shear strain intensities for varying Esmarch overlap and width Figures 207 6.00 -e. ie • • -e.26 •• 6.56 ESMARCH OVERLAP Origin Rt 6.6,6.6 a. Single-layer model 16 •/. CUFF PRESSURE 26 y. CUFF PRESSURE _ _ _ 36 7. CUFF PRESSURE .... 46 y. CUFF PRESSURE 56 2 CUFF PRESSURE -6.16 6.56 -8.28 1.66 ESMARCH OVERLAP Origin At 8.8,8.6 b. Multi-layer model 16 2 CUFF PRESSURE _ _ 20 y. CUFF PRESSURE M M . 36 •/. CUFF PRESSURE .... 40 y. CUFF PRESSURE 50 y. CUFF PRESSURE Figure 5.60: Average maximum axial strain intensities for varying Esmarch overlap and cuff pressure Figures -8.55 + -8.65 + 208 ESMARCH OVERLAP Origin Rt 8.8,8.8 a. Single-layer model IB X CUFF PRESSURE 26 x CUFF PRESSURE 36 X CUFF PRESSURE m m m m 48 X CUFF PRESSURE 56 X CUFF PRESSURE -8.78 8.56 -8.681 _ — \\ H ^ a*. -B.98 + -1.88 + ESMARCH OVERLAP Origin At 8.8,8.8 18 X CUFF PRESSURE 28 Z CUFF PRESSURE 38 X CUFF PRESSURE • • • • 46 X CUFF PRESSURE 58 X CUFF PRESSURE b. Multi-layer model Figure 5.61: Average maximum shear strain intensities for varying Esmarch overlap and cuff pressure 209 Figures -8.15 • • ESMARCH WIDTH (MM) Origin At 8.8,8.8 a. Single-layer model 18 7. CUFF PRESSURE — _ 28 7. CUFF PRESSURE 38 Z CUFF PRESSURE • - - • 48 7. CUFF PRESSURE 58 7. CUFF PRESSURE -8.18 CK -8.15 • • 20.80 48.88 ESMARCH WIDTH (MM) Origin At 8.8,8.8 b. Multi-layer model 18 Z CUFF PRESSURE 28 2 CUFF PRESSURE 38 1 CUFF PRESSURE • • - - 48 X CUFF PRESSURE 58 t CUFF PRESSURE Figure 5.62: Average maximum axial strain intensities for varying Esmarch width and cuff pressure Figures -s.« B.53 - • -8.57 • • 2.88 I 4.88 4 210 ESMARCH WIDTH Origin Rt 8.8,8.8 a. Single-layer model 18 X CUFF PRESSURE 28 X CUFF PRESSURE 38 X CUFF PRESSURE m m • m 48 X CUFF PRESSURE 58 X CUFF PRESSURE ESMARCH WIDTH Origin Rt 8.8,8.8 b. Multi-layer model IB X CUFF PRESSURE — 28 X CUFF PRESSURE 38 X CUFF PRESSURE - - - . 48 X CUFF PRESSURE 58 X CUFF PRESSURE Figure 5.63: Average maximum shear strain intensities for varying Esmarch width and cuff pressure Figures 211 b. Optimal Esmarch/tourniquet configuration Figure 5.64: Comparison of predicted axial strain profiles (single-layer model) Figures 212 a. Conventional pneumatic tourniquet b. Optimal Esmarch/tourniquet configuration Figure 5.65: Comparison of predicted shear strain profiles (single-layer model) Figures 213 c u f f s o f t t i s s u e i n i t i a l l o s s o f e f f e c t i v e w i d t h s u s t a i n e d l o s s o f e f f e c t i v e w i d t h Figure 5.66: Schematic representation of the pneumatic tourniquet as it is inflated Figures 214 Figure 5.67: Load reduction induced by upward-curving of the cuff edges Figure 5.68: Cross-section of the collapsed artery Figures 216 2BB.ee --CO E e ce r> co CO UJ ce =3 _ J o (_> o i6e.ee •• 12B.B8 --26.68 48.88 CUFF WIDTH (CR) Origin At 6.8,118.88 EXPERIMENTAL RESULTS 15 CN ARTERY m - m m 17.5 CR ARTERY 22.5 CH ARTERY Figure 5.69: Predicted occlusion pressures for varying cuff width and artery length Figure 5.70: Predicted occlusion pressures for varying cuff width and ET ures 217 ro e DC zz> co 4e.ee -• £ i6B.ee Q_ Z o »—t\" CO = > _ J < _ > <_> o 126.BG I CUFF WIDTH (cn) Origin At B.6.116.86 16.68 26.88 38.88 EXPERIMENTAL RESULTS Et - 275 888 Pa Et = 558 88S Ps Et : 825 868 Pa Figure 5.71: Predicted occlusion pressures for varying cuff width and Ee 288.68 '-co 8 168.88 '• 126.88 ' -•4-18.88 28.88 34.86 CUFF WIDTH (CM) Origin At 8.8,118.88 Experimental Ez : 188 see Pa .... Ez : 288 888 Pa Ez : 388 eee Pa Figure 5.72: Predicted occlusion pressures for varying cuff width and E. Figures 218 Figure 6.1: Proposed multi-bladder tourniquet Figures 219 Figure 6.2: Proposed Esmarch/tourniquet configuration Figures 220 i n d i v i d u a l sensor // to computer a. Piezoelectric sensor b. Potentiometer style sensor Figure 6.3: Examples of pressure sensors Figures 221 Figure 6.4: Example of experimental setup to investigate blood flow occlusion Appendix A NERVE ANATOMY The structural features of peripheral nerves are shown in Figure A .1 . The nerve trunk (bottom left) has been cut away to expose a single fasciculus, on which three fibers are indicated in detail. These include two myelinated axons, one on each side of a group of non-myelinated axons enclosed within a Schwann cell sheath. The myelinated fiber on the bottom has been cut away at various points to demonstrate the relationship between the axon, the Schwann cell, and its sheath of myelin. Figure A.1: Structural features of a peripheral nerve [46] 222 Appendix A. NERVE ANATOMY 223 The general plan of a myelinated nerve fiber in longitudinal section including one complete internodal segment and two adjacent paranodal bulbs is shown in Figure A.2. Figure A.2a shows a transverse section through the center of a node of Ranvier, while Fig-ure A.2b shows the arrangement of the axon, myelin sheath and Schwann cell cytoplasm at the node of Ranvier in the paranodal bulb. a. Transverse section through the node of Ranvier b. Arragement of the axon Figure A.2: General plan of a myelinated nerve fiber [46] Appendix B F I N I T E E L E M E N T T H E O R Y Using first order shape functions associated with rectangular elements possessing four nodes, a stiffness matrix is constructed to reflect the properties of a single finite element under plane stress conditions. This is followed by a demonstration of the assembly of a global stiffness matrix. Figure B.l shows the finite element to be used in this development. (-1.D Cf (-i.-i) cd.D (1 , -D Figure B.l: Single finite element [71] Equation B.l lists the linear functions associated with each node of the element. N1 = (l-x){l-y)/A JV2 = (l + *)(l - l O/4 JVs = (l+*)(l+y)/4 N4 = {l-x){l+y)/4 (B.l) 224 Appendix B. FINITE ELEMENT THEORY 225 Note that the displacements at any given coordinate (x,y) are calculated using Equa-tion B.2 where u signifies displacement in the x direction while v is in the y direction. {*} = JVa N2 N3 N4 0 0 0 0 0 0 0 0 Ni N2 N3 N4 a-! A3 a.4 as o 7 a 8 (B.2) In Equation B.2, ai...a4 represent the displacements at each of the corner nodes in the x direction, while 05...ag represent the displacements in the y direction. The strain relationship is given by: {e} = \\L][N]{a} (B.3) where: I 0 [L] = 0 # By §_ By Bx yf Appendix B. FINITE ELEMENT THEORY 226 Furthermore, stresses at each element can be evaluated by incorporating the material properties into the problem. Assuming a homogeneous isotropic material, Equation B.4 reflects the stresses at each element. {*} = (B.4) where [D} = (1 - u>) 1 v 0 v 1 0 0 0 ^ The finite element method requires that the total energy be defined for each ele-ment (this implies strain and potential energies). Equations B.5 through B.7 show the development of the strain energy relationship. U = \\jv{cr}T{e}dV (B.5) U = { ]A{°}T{z}dA (B.6) U = \\ jAU}TlN}T[L}T[D}[L}[N}{a}dA (B.7) The potential energy of the internal and external loads is given by the negative of the body forces and surface tractions times the displacements. Equations B.8 and B.9 show the potential energy relationship. PE = - I {F}T{V}dV - I {T}T{V}dT (B.8) Jv Jr PE = -tJ^{F}T[N}dA{a}-J^{T}T[N]dT{a} (B.9) Appendix B. FINITE ELEMENT THEORY 227 By combining the strain and potential energy equations and applying Lagrange's theorem, the stiffness equation is set up. Equations B. 10 through B.12 below show this development. W = U + PE = Ua} T I \\N}T[L)T\\D)\\L)\\N)dA{a} - t j {F}T[N}dA{a} 2 JA J A - Jr{T}T[N)dT{a} (B.10) ^ = t JA[N)T[L]T[D][L}[N}dA{a} - t J^{F}T[N]dA - j^{T)T[N)dT = 0 (B.l l) [*M«} = { /h (B.12) where [k]i = J[N]T[L]T[D][L][N]dA stiffness matrix {/}a = t I {F}T[N]dA for each element with body forces J A 4- J {T}T[N]dT along the boundary of elements having edge loads Solving these equations results in an 8 by 8 stiffness matrix and an 8 term force vector (i.e. 8 degrees of freedom, two at each of the four nodes). From this development a stiffness matrix and force vector can be established for a single element. The next step is to combine all the individual stiffness matrices and force vectors into one global stiffness equation. Figure B.2 represents a simple two element structure along with the associated degrees of freedom. (Each of the two elements exhibit the same individual stiffness matrix.) As before, each element possesses eight degrees of freedom while the combined struc-ture has twelve ( 6 x 2 D.O.F/node). Remembering that C ! . . . a 4 represent displacements in the x direction and that ah...a8 represent displacements in the y direction, the loca-tor matrix of Equation B.l3 can be constructed by associating the individual degrees of freedom of each element with the global degrees of freedom of the combined structure. Appendix B. FINITE ELEMENT THEORY 228 Figure B.2: Simple two element structure element a.\\ a2 0,3 0,4 as ae 0,7 ag 1 1 2 3 4 5 6 7 8 (B.13) 2 2 9 10 3 6 11 12 7 ' Using Equation B.13 the global stiffness matrix can be assembed element by element as follows: (1.1) O f [ f c ] ! (1.2) of [fc], (1.1) <*[/-*] (1.2) of [K] (1.1) of[fc]2 — (2,2) of [K] (1.2) of[fc]2 — > (2,9)of[X] /f Finally, a similar technique is used to assemble the global force vector as well as to incorporate the boundary conditions. Appendix C ANSYS PROGRAM LISTINGS c*** C*** RCX)T FILE TO SET THE PARAMETERS OF THE C*** HOMOGENEOUS ESMARCH/CUFF LIMB COMPRESSION MODEL C*** /PREP7 /TITLE ARM SECTION - **** •SET,RAD 1,.05 •SET,CUFF,.10 •SET,OFFS,0.00 •SET,PEAK,1 •SET,BONN,1 •SET,SKIN,1 •SET,ENDS,0 •SET,MESH,7 •SET,ESMU,0.02 •SET,ESMO,0.50 *SET,ESMP,0.1 •SET,ESMU,0.0 /INPUT,MODEL AFURIT FINISH /EXE /INPUT,27 FINISH /POST1 /INPUT,OUTPUT FINISH LIMB RADIUS CUFF WIDTH OFFSET OF PRESSURE PROFILE NUMBER OF PEAKS BONE/MUSCLE INTERFACE SETTING SKIN/CUFF INTERFACE SETTING AXIAL ENDS SETTING RADIAL MESH ESMARCH WIDTH ESMARCH OVERLAP ESMARCH PRESSURE ESMARCH OFFSET PRESSURE CALL THE PROGRAM TO BUILD THE MODEL COMPILE THE PROGRAM • EXECUTE THE PROGRAM • PERFORM ANALISYS ON OUTPUT if 229 Appendix C ANSYS PROGRAM LISTINGS 230 c***»»***********»********************»»*»***********»*«* C*** THIS PROGRAM CONSTRUCTS THE HOMOGENEOUS C*»* ESMARCH/CUFF LIMB COMPRESSION MODEL ET,1,25 * CHOOSE ELEMENT TYPE EX,1,15000 * SET MATERIAL PROPERTIES EY,1,7500 EZ,1,15000 NUXY,1,0.45 NUYZ.1,0.45 NUXZ.1,0.49 C*** C*** C*** SET UP NODES AND ELEMENTS C*** C*** EDELE.ALL * ERASE AND COMPRESS ALL NDELE.ALL * NODES AND ELEMENTS ECOMPR NCOMPR *SET,BONE,RADI*0.30 * SET PARAMETERS FOR •SET,RINC.RADI-BONE • CONSTRUCTION •SET.RINC.RINC/MESH •SET,AINC,0.0025 •SET,MES,MESH+1 •SET,X,BONE * SET INITIAL CONDITIONS •SET,NOD,1 •BEGIN,CONS • LOOP TO PLACE NODES N,NOD,X,0 * ON MODEL NGEN,61,MES,N0D,N0D,1,,AINC •SET,NOD,NOD+1. •SET.X.X+RINC •END •DO,CONS,1,MESH,1 E,1,2,MES+2,MES+1 * PLACE ELEMENTS ON MODEL EGEN,MESH,1,1,1,1 EGEN,60,MES,1,MESH,1 WSORT.Y • SORT THE ELEMENTS IN THE C*** • AXIAL DIRECTION C*** C*** SET THE BOUNDARY CONDITIONS C*** C*** •SET,STAR,-CUFF/2 *SET,STAR,STAR*0.15 •IF,SKIN,EQ.O,HERE,10 • SET B.C. FOR CUFF/SKIN INTERFACE NSEL.X.RADI-0.0001,RADI+0.0001 * SKIN=0 : FREE TO SLIDE AX1ALLY DDELE.ALL * SKIN=1 : RESTRAINED NRSEL.Y.STAR-O.001,0.151 D,ALL,UY,0 NALL EALL •GO,HERE,5 NSEL.X.RADI-0.0001,RADI+0.0001 DDELE.ALL NALL EALL * •IF,BONN,EQ,0,HERE,7 * SET B.C. FOR BONE/MUSCLE INTERFACE NSEL.X,BONE,BONE * BONN=0 : FREE TO SLIDE AXIALLY D,ALL,UX,0 * BONN=1 : RESTRAINED D,ALL,UY,0 NALL EALL •GO,HERE,6 NSEL.X,BONE,BONE DDELE.ALL D,ALL,UX,0 NALL EALL *IF,ENDS,EQ,0,HERE,5 * SET B.C. FOR END OF MODEL NSEL,Y,0,0 * ENDS=0 : FREE TO EXPAND AXIALLY D,ALL,LIYJ0 * ENDS=1 : RESTRAINED Appendix C. ANSYS PROGRAM LISTINGS 231 NAIL EALL NSEL.Y,0.15,0.15 D,ALL,UY,0 NALL EALL C*** C*** C*** SET THE PRESSURE DISTRIBUTION C*** C*** *SET,CIRC,RADI*6.283185308 *SET,POCC,CIRC*16 *SET,POCC,POCC/CUFF *SET,POCC,POCC*133.0 *SET,POCC,POCC+10000.0 PDELE.ALL •SET,OVER,ESMW*ESMO *SET,IOVE,ESMW-OVER *SET,A,STAR-lOVE *SET,OMEE,ESMW**-1 •SET,0MEE,0MEE*6.2832 *SET,LINC,0.0025 •SET,1,0 *SET,E,ESMU *SET,EE,ESMU-1.0 •SET,EE,EE/2.0 *SET,FF,ESMU+1.0 •SET.FF.FF/2.0 •SET,DIV.1OVE/0.0025 •BEGIN,CONS *SET,B,A+L1NC •SET,I,I+LINC *SET,F,COS(OMEE*I> *SET,F,EE*F •SET,F,F+FF •SET.PPRF.E+F •SET.PPRF.PPRF/2.0 •SET,PPRF,PPRF*ESMP *SET,PPRF,PPRF*POCC NSEL,Y,A-.001,B+.001 NRSEL,X,RADI-0.0001,RADI+0.002 PSF,0,0,RADI,PPRF •SET.A.B •SET,E,F •END *DO,CONS,1,DIV-1,1 NALL EALL •SET,A,STAR •SET,OMEG,CUFF**-1 •SET,OMEG,OMEG*PEAK •SET,OMEG,0MEG*6.2832 •SET,LINC,0.0025 •SET,H,0 •SET,C,OFFS *SET,CC,OFFS-1.0 •SET.CC.CC/2.0 *SET,DD,OFFS+1.0 •SET,DD,DD/2.0 •SET,DIV,OVER/0.0025 •BEGIN,CONS *SET,B,A*LINC •SET,H,H+LINC *SET,D,COS(OMEG*H) *SET,D,CC*D •SET,D,D+DD •SET.PPRE.C+D *SET,PPRE,PPRE/2.0 •SET.I.I+LINC *SET,F,COS(OMEE*I, *SET,F,EE*F •SET,F,F+FF • SET B.C. AT SYMMETRY AXIS • CALCULATE OCCLUSION PRESSURE • USING CUFF WIDTH AND LIMB RADIUS • SET INITIAL VALUES FOR • ESMARCH P.D. • BEGIN ESMARCH LOOP END ESMARCH LOOP SET INITIAL CONDITIONS FOR ESMARCH/CUFF P.D. • BEGIN ESMARCH/CUFF LOOP Appendix C. ANSYS PROGRAM LISTINGS 232 •SET.PPRF.E+F *SET,PPRF,PPRF/2.0 *SET,PPRF,PPRF*ESMP •SET.PPR.PPRF+PPRE *SET,PPR,PPR*POCC NSEL,Y,A-.001,B+.001 NRSEL.X.RADI-0.0001,RADI+O.002 PSF,0,0,RAOI,PPR •SET,A.B •SET.C.D •SET,E.F •END • END ESMARCH/CUFF LOOP *D0,CONS,1,DIV-1,1 •SET,DIST,STAR+OVER * SET INITIAL CONDITIONS FOR •SET,DIST,-DIST • CUFF P.D. *SET,DIST,DIST+0.15 •SET,DIV.DIST/0.0025 •BEGIN,CONS * BEGIN CUFF LOOP •SET.B.A+LINC •SET,H,H+LINC •SET,D,COS(OMEG*H) *SET,D,CC*D *SET,D,D+DD •SET,PPRE,C+D •SET.PPR.PPRE/2.0 *SET,PPR,PPR*POCC NSEL,Y,A-.O01,B+.0O1 NRSEL,X,RADI-0.0005,RADI+O.002 PSF,0,0,RADI,PPR •SET,A.B •SET.C.D •END • END CUFF LOOP *DO,CONS,1,DIV-1,1 NALL EALL C*** C*** C*** END OF PROGRAM C*** Appendix C. ANSYS PROGRAM LISTINGS 233 £**************»**********************#***************»***************«* c*** C*** THIS PROGRAM PRODUCES THE OUTPUT FROM C*** HOMOGENEOUS ESMARCH/CUFF LIMB COMPRESSION MODEL C*** C*** STRESS,EX,25,37 STRESS,EY,25,38 STRESS,EZ,25,39 STRESS,EXY,25,40 SET,1,1 *SET,EMAX,MESH*60 ESEL,ELEM,1,EMAX,MESH*2 PRSTRS ESEL,ELEM,3,EMAX,MESH*2 PRSTRS ESEL,ELEM,MESH,EMAX,MESH*2 PRSTRS EALL NALL NSEL.NODE,1,481,16 PRNSTR NSEL,NODE,4,484,16 PRNSTR NSEL.NODE,7,487,16 PRNSTR EALL NALL DEFINE STRAINS PRINT STRAINS FOR RADIAL NERVE PRINT STRAINS FOR MUSCULO NERVE PRINT STRAINS FOR MEDIAN AND ULNAR NERVES PRINT STRESSES FOR RADIAL NERVE PRINT STRESSES FOR MUSCULO NERVE PRINT STRESSES FOR MEDIAN AND ULNAR NERVES C*** ROOT FILE TO SET THE PARAMETERS OF THE C*** NON HOMOGENEOUS ESMARCH/CUFF LIMB COMPRESSION MODEL C*** /PREP7 /TITLE ARM SECTION - **** *SET,RADI,.05 * LIMB RADIUS *SET,CUFF,.10 * CUFF WIDTH *SET,OFFS,0.00 * OFFSET OF PRESSURE PROFILE •SET,PEAK,1 * NUMBER OF PEAKS *SET,FAT,10 * FAT CONTENT *SET,BONN,1 * BONE/MUSCLE INTERFACE SETTING •SET,SKIN,1 • SKIN/CUFF INTERFACE SETTING •SET,ENDS,0 * AXIAL ENDS SETTING •SET,MESH,7 * RADIAL MESH •SET,ESMW,0.02 * ESMARCH WIDTH •SET.ESMO.O.O * ESMARCH OVERLAP *SET,ESMP,0.1 * ESMARCH PRESSURE •SET,ESMU,0.0 * ESMARCH OFFSET PRESSURE /INPUT,MODEL * CALL THE PROGRAM TO BUILD THE MODEL AFWRIT • COMPILE THE PROGRAM FINISH /EXE EXECUTE THE PROGRAM /INPUT,27 FINISH /POST1 * PERFORM ANAL I SYS ON OUTPUT /INPUT,OUTPUT FINISH Appendix C. ANSYS PROGRAM LISTINGS c*** C*** THIS PROGRAM CONSTRUCTS THE NON HOMOGENEOUS C*** ESMARCH/CUFF LIMB COMPRESSION MODEL C*** ET.1,25 EX,1,15000 EY,1,7500 EZ,1,15000 NUXY.1,.45 NUYZ.1,.45 NUXZ.1,.49 ET.2,81 EX,2,250000 DENS,2,1000 C*** C*** C*** SET UP NODES AND ELEMENTS C*** C*** EDELE.ALL NDELE.ALL ECOMPR NCOMPR •SET,FAT,FAT/100 •SET,FAT,-FAT *SET,FAT,FAT+1 *SET,FAT,FAT**0.5 •SET,FAT,-FAT •SET.FAT.FAT+1 •SET,FAT,FAT*RADI •SET,BONE,RAD 1*0.30 •SET,RINC.RADI-BONE •SET,RINC,RINC-FAT •SET.RINC.RINC/MESH •SET,AINC,0.0025 *SET,MES,MESH+3 •SET,X,BONE •SET, NCO, 1 •BEGIN,CONS N,NOD,X,0 NGEN.61,MES,NOD,NOD,1,,AINC *SET,NOD,NOO+1 •SET.X.X+RINC •END •DO,CONS,1,MESH,1 •SET.X.X-RINC N,NOD,X+FAT NGEN,61,MES,NOD,NOD,1,,AINC •SET.X.X+FAT N.NOD+1.X+0.001 NGEN.61,MES,NOD+1,NOD+1,1,,AINC MAT, 1 TYPE,1 E,1,2,MES+2,MES+1 EGEN,MESH,1,1,1,1 EGEN,60,MES,1,MESH,1 MAT,2 TYPE,2 •SET,BB,MES+MESH E.MESH+1,MESH+2,BB+2,BB+1 •SET,ELLI,MESH*60 *SET,ELLI,ELLI+1 EGEN,60,MES,ELLI,ELLI MAT.1 TYPE,1 •SET,ELL,MESH*60 •SET,ELL,ELL+61 *SET,CC,MES*2 E,MES-1,MES,CC,CC-1 EGEN,60,MES,ELL,ELL,1 WSORT.Y C*** CHOOSE ELEMENT TYPE FOR MUSCLE SET MATERIAL PROPERTIES CHOOSE ELEM.ENT TYPE FOR FAT SET MATERIAL PROPERTIES ERASE AND COMPRESS ALL NODES AND ELEMENTS CALCULATE FAT THICKNESS FROM FAT X SET PARAMETERS FOR CONSTRUCTION SET INITIAL CONDITIONS LOOP TO PLACE NODES ON MODEL DEFINE THE MUSCLE ELEMENTS • DEFINE FATTY TISSUE ELEMENTS • DEFINE THE SKIN ELEMENTS SORT THE ELEMENTS IN THE AXIAL DIRECTION Appendix C. ANSYS PROGRAM LISTINGS c*** C*** SET THE BOUNDARY CONDITIONS C*** C*** •SET,STAR,-CUFF/2 •SET.STAR.STAR+0.15 •IF,SKIN,EQ,0,HERE,10 NSEL.X,RADI+O.0005,RAD 1*0.002 DDELE.ALL NRSEL.Y.STAR-O.001,0.151 D,ALL,UY,0 NALL EALL •CO,HERE,5 NSEL.X,RAD 1+0.0005,RAD 1+0.002 DDELE.ALL NALL EALL •IF,BONN,EG,O.HERE,7 NSEL.X,BONE,BONE D.ALL.UX.O D,ALL,UY,0 NALL EALL •GO,HERE,6 NSEL.X,BONE,BONE DDELE.ALL D,ALL,UX,0 NALL EALL •IF,ENDS,EQ,0,HERE,5 NSEL.Y.O.O D.ALL.UY.O NALL EALL NSEL,Y,0.15,0.15 O.ALL.UY.O NALL EALL C*** C*** SET THE PRESSURE DISTRIBUTION 235 SET B.C. FOR CUFF/SKIN INTERFACE SKIN=0 : FREE TO SLIDE AXIALLY SKIN=1 : RESTRAINED SET B.C. FOR BONE/MUSCLE INTERFACE BONN=0 : FREE TO SLIDE AXIALLY BONN=1 : RESTRAINED • SET B.C. FOR END OF MODEL • ENDS=0 : FREE TO EXPAND AXIALLY • ENDS=1 : RESTRAINED • SET B.C. AT SYMMETRY AXIS C*** C*** •SET •SET •SET •SET •SET PDELE,ALL •SET •SET •SET •SET •SET •SET •SET •SET •SET •SET •SET •SET •SET •BEG •SET •SET •SET •SET •SET •SET •SET •SET •SET CIRC,RAD 1*6.283185308 P0CC,CIRC*16 POCC.POCC/CUFF POCC,POCC*133.0 POCC.POCC+10000.0 OVER,ESMV*ESMO 10VE,ESMU-OVER A. STAR-IOVE OMEE,ESMW**-1 OMEE,OMEE*6.2832 LINC,0.0025 1.0 E. ESMU EE.ESMU-1.0 EE,EE/2.0 FF.ESMU+1.0 FF.FF/2.0 DIV.IOVE/0.0025 N.CONS B. A+LINC I.I+LINC F, COS(OMEE*I> F,EE*F F.F+FF PPRF.E+F PPRF.PPRF/2.0 PPRF,PPRF*ESMP PPRF,PPRF*POCC • CALCULATE OCCLUSION PRESSURE • USING CUFF WIDTH AND LIMB RADIUS • SET INITIAL VALUES FOR • ESMARCH P.D. BEGIN ESMARCH LOOP Appendix C. ANSYS PROGRAM LISTINGS 236 NSEL,Y.A-.001,B+.001 NRSEL.X,RADI+O.0005,RADI+O.002 PSF,0,0,RADI+O.001,PPRF *SET,A,B •SET.E.F •END •D0,C0NS,1,DIV-1,1 NALL EALL •SET •SET •SET •SET •SET •SET •SET •SET •SET •SET •SET •SET •BEGI •SET •SET •SET •SET •SET •SET •SET •SET •SET •SET •SET •SET •SET •SET •SET •SET NSEL A, STAR 0MEG,CUFF**-1 OMEG,OMEG*PEAK OMEG,OMEG*6.2832 LINC,0.0025 H,0 COFFS CC.OFFS-1.0 CC.CC/2.0 DD.OFFS+1.0 DD.DD/2.0 DIV,OVER/0.0025 N.CONS B. A+LINC H. H+LINC D,COS(OMEG*H) D,CC*0 D.D+DD PPRE.C+D PPRE.PPRE/2.0 I. I+LINC F,C0$(OMEE*I> F,EE*F F.F+FF PPRF.E+F PPRF.PPRF/2.0 PPRF,PPRF*ESMP PPR.PPRF+PPRE PPR,PPR*P0CC Y,A-.001,B+\".001 ' NRSEL.X,RADI+O.0005,RADI+O.002 PSF,0,0,RADI+O.001,PPR •SET.A.B •SET.C.D •SET.E.F •END •D0,CONS,1,DIV-1.1 *SET,D1ST,STAR+0VER *SET,DIST,-DIST •SET,DIST,DIST+0.15 •SET,DIV,D1ST/0.0025 •BEGIN,CONS •SET.B.A+LINC •SET.H.H+LINC *SET,D,COS(0MEG*H> •SET,D,CC*D •SET,D,D+DD •SET,PPRE,C+D •SET,PPR,PPRE/2.0 •SET,PPR,PPR*POCC NSEL,Y.A-.001,B+.001 NRSEL.X,RADI+O.0005,RADI+O.002 PSF,0,0,RADI+O.001,PPR •SET.A.B *SET,C,0 •END •DO,CONS,1,DIV-1,1 NALL EALL C*«« C*** C*** END OF PROGRAM END ESMARCH LOOP • SET INITIAL CONDITIONS FOR • ESMARCH/CUFF P.D. BEGIN ESMARCH/CUFF LOOP • END ESMARCH/CUFF LOOP • SET INITIAL CONDITIONS FOR • CUFF P.D. • BEGIN CUFF LOOP • END CUFF LOOP Appendix C. ANSYS PROGRAM LISTINGS 237 c*** C*** THIS PROGRAM PRODUCES THE OUTPUT FROM C*** NON HOMOGENEOUS ESMARCH/CUFF LIMB COMPRESSION MODEL C*** C*** STRESS,EX,25,37 STRESS,EY,25,38 STRESS,EZ,25,39 STRESS,EXY,25,40 SET,1,1 *SET,EMAX,MESH*60 ESEL.ELEM,1,EMAX,MESH*2 PRSTRS ESEL.ELEM,3,EMAX,MESH*2 PRSTRS ESEL.ELEM,MESH,EMAX,MESH*2 PRSTRS EALL NALL NSEL,NODE,1,481,16 PRNSTR NSEL,NODE,4,484,16 PRNSTR NSEL,NODE,7,487,16 PRNSTR EALL NALL DEFINE STRAINS PRINT STRAINS FOR RADIAL NERVE PRINT DATA FOR MUSCULO NERVE PRINT DATA FOR MEDIAN AND ULNAR NERVES PRINT STRESSES FOR RADIAL NERVE PRINT STRESSES FOR MUSCULO NERVE PRINT STRESSES FOR MEDIAN AND ULNAR NERVES ROOT FILE TO SET THE PARAMETERS OF HOMOGENEOUS LIMB COMPRESSION MODEL C*** C*** C*** C*** /PREP7 /TITLE ARM SECTION - **** *SET,PRES,2 •SET,RAD I,.05 •SET,CUFF,.10 •SET,OFFS,0.00 •SET,PEAK,1 •SET,BONN,1 •SET,SKIN,1 •SET,ENDS,0 •SET,MESH,7 •SET,ORTH,1 •SET,XMOD,15000 •SET,YMOO,7500 •SET,XYU,0.45 •SET,XZU,0.49 /INPUT,MODEL AFWRIT FINISH /EXE /INPUT,27 FINISH /POST1 /INPUT,OUTPUT FINISH C*** THE PRESSURE PROFILE LIMB RADIUS CUFF WIDTH OFFSET OF PRESSURE PROFILE NUMBER OF PEAKS BONE/MUSCLE INTERFACE SETTING SKIN/CUFF INTERFACE SETTING AXIAL ENDS SETTING RADIAL MESH MATERIAL TYPE (ISO OR ORTHO) MODULUS OF ELASTICITY (RADIAL AND HOOP) MODULUS OF ELASTICITY (AXIAL) POISSON RATIO (XY) POISSON RATIO (XZ AND YZ) CALL THE PROGRAM TO BUILD THE MODEL COMPILE THE PROGRAM • EXECUTE THE PROGRAM PERFORM ANALISYS ON OUTPUT Appendix C. ANSYS PROGRAM LISTINGS 238 CHOOSE ELEMENT TYPE ORTHOTROPIC PROPERTIES ISOTROPIC PROPERTIES £****************»****»*»***»**»************************* c*** C*** THIS PROGRAM CONSTRUCTS THE HOMOGENEOUS C*** LIMB COMPRESSION MODEL C*** ET,1,25 *IF,ORTH,EQ,0,HERE,8 EX,1,XMOD EY,1,YMOD EZ.1.XMOD NUXY,1,XYU NUYZ,1,XYU NUXZ,1,XZU *G0,HERE,7 EX.I.XMOD EY.1.XMOD EZ.1.XMOD NUXY,1,XYU NUYZ,1,XYU NUXZ,1,XYU C*** C*** C*** SET UP NODES AND ELEMENTS C*** C*** EDELE.ALL NDELE.ALL ECOMPR NCOMPR *SET,BONE,RAD 1*0.30 *SET,RINC,RADI-BONE *SET,RINC,RINC/MESH •SET,AINC,0.0025 *SET,MES,MESH+1 •SET,X,BONE •SET,NOD,1 •BEG IN,CONS N,NOD,X,0 NGEN,61,MES,N0D,N0D,1,,AINC *SET,NOD,NOD+1 •SET.X.X+RINC •END •DO,CONS,1,MESH,1 E,1,2,MES+2,MES+1 EGEN,MESH,1,1,1,1 EGEN,60,MES.1,MESH,1 USORT.Y C*** C*** SET THE BOUNDARY CONDITIONS C*** C*** •SET,STAR,-CUFF/2 •SET,STAR,STAR+0.15 •IF,SKIN,EQ,0,HERE,10 NSEL,X,RADI-0.0001,RADI+0. DDELE.ALL NRSEL,Y,STAR-0.001,0.151 D.ALL.UY.O NALL EALL •GO,HERE,5 NSEL,X,RADI-0.0001,RAD1+0.0001 DDELE.ALL NALL EALL •IF,BONN,E0,0,HERE,7 NSEL,X,BONE,BONE D,ALL,UX,0 D,ALL,UY,0 NALL EALL •GO,HERE,6 ERASE AND COMPRESS ALL NODES AND ELEMENTS SET PARAMETERS FOR CONSTRUCTION SET INITIAL CONDITIONS LOOP TO PLACE NODES ON MODEL PLACE ELEMENTS ON MODEL SORT THE ELEMENTS IN THE AXIAL DIRECTION 0001 SET B.C. SKIN=0 : SKIN=1 : FOR CUFF/SKIN INTERFACE FREE TO SLIDE AXIALLY RESTRAINED SET B.C. BONN=0 : BONN=1 : FOR BONE/MUSCLE INTERFACE FREE TO SLIDE AXIALLY RESTRAINED Appendix C. ANSYS PROGRAM LISTINGS 239 NSEL,X,BONE,BONE DDELE.AU D,ALL,UX,0 NALL . EALL *IF,ENDS,EQ,O.HERE,5 NSEL,Y,0,0 D,ALL,UY,0 NALL EALL NSEL,Y,0.15,0.15 D,ALL,UY,0 NALL EALL C*** C*** C*** SET THE PRESSURE DISTRIBUTION C*** C*** *SET,CIRC,RAD I*6.283185308 *SET,P0CC,CIRC*16 *SET,POCC,POCC/CUFF *SET,POCC.POCC*133.0 •SET,POCC.POCC+10000 •IF,PRES.EO,2,HERE,8 •IF,PRES.EQ,3,HERE,37 PDELE.ALL NSEL,Y,STAR-0.001,0.151 NRSEL.X.RADI-0.0001,RADI+0.0001 ENODE PSF,0,0,RADI,POCC •GO,HERE,73 •SET,A,STAR •SET,OMEG,CUFF**-1 •SET,OMEG,OMEG*PEAtC *SET,OMEG,OMEG*6.2832 •SET,LINC,0.0025 *SET,H,0 •SET,C,OFFS *SET,CC,OFFS-1.0 •SET.CC.CC/2.0 *SET,DD,OFFS+1.0 *SET,DD,DD/2.0 •SET,DIV,CUFF/O.005 PDELE.ALL •BEGIN,CONS •SET.B.A+LINC •SET.H.H+LINC •SET,D,COS(OMEG*H) •SET,D,CC*D •SET.D.D+DD *SET,PPRE,C+D *SET,PPRE,PPRE/2.0 *SET,PPRE,PPRE*POCC NSEL,Y,A-.001,B+.001 NRSEL,X,RADI-0.0001,RADI+0.0001 PSF,0,0,RADI,PPRE •SET.A.B *SET,C,D •END *DO,CONS,1,DIV-1,1 •GO,HERE,43 •SET,A,STAR •SET,MID,CUFF/2 •SET,FACT,CUFF**-2 •SET,FACT,FACT*4 •SET,LINC,0.0025 •SET,H,0 •SET.C.O •SET,DIV,CUFF/0.005 •IF,CUFF,LT,0.15,HERE,2 •SET,DIV,DIV-2 PDELE.ALL SET B.C. FOR END OF MODEL ENDS=0 : FREE TO EXPAND AXIALLY ENDS=1 : RESTRAINED * SET B.C. AT SYMMETRY AXIS CALCULATE OCCLUSION PRESSURE USING CUFF WIDTH AND LIMB RADIUS * SET THE PRESSURE DISTRIBUTION * PRES=1 : RECTANGULAR P.D. * PRES=2 : SINUSOIDAL P.D. *. PRES=3 : EXPONENTIAL P.D. SET RECTANGULAR P.D. SET INITIAL CONDITIONS FOR SINUSOIDAL P.D. * BEGIN SINUSOIDAL LOOP END SINUSOIDAL LOOP • SET INITIAL CONDITIONS FOR • EXPONENTIAL P.D. endix C. ANSYS PROGRAM LISTINGS •BEGIN,CONS • BEGIN EXPONENTIAL LOOP •SET,B,A+LINC •SET,H,H+LINC •SET.D.MIO-H *SET,D,D**2 •SET,D,0*FACT *SET,D,D**-1 *SET,0,D-1 *SET,D,-D *SET,D,EXP(D) *SET,D,D-1 *SET,D,-D *SET,PPRE,C+D *SET,PPRE,PPRE/2.0 *SET,PPRE,PPRE*POCC NSEL,Y,A-.001,B+.001 NRSEL.X,RADI-0.0001,RADI+O.0001 PSF,0,0,RADI,PPRE •SET.A.B •SET.C.D •END • END EXPONENTIAL LOOP *DO,CO«S,1,DIV-2,1 NALL EALL •IF,CUFF,LT,0.15,HERE,2 •SET,LINC,LINC*3 •SET.MIN.-LINC * SET MIDDLE VALUES TO PMAX •SET.MIN.MIN+.149 • FOR EXP. P.D. NSEL,Y,MIN,0.151 NRSEL.X,RADI-0.0001,RADI+0.0001 PSF,0,0,RADI,POCC NALL EALL C*** C*** C*** END OF PROGRAM C*** C*** Appendix C. ANSYS PROGRAM LISTINGS c*** C*** THIS PROGRAM PRODUCES THE OUTPUT FROM THE C*** HOMOGENEOUS LIMB COMPRESSION MODEL C*** STRESS,EX,25,37 STRESS,EY,25,38 STRESS,EZ,25,39 STRESS,EXY,25,40 SET,1,1 *SET,EMAX,MESH*60 ESEL.ELEM,1,EMAX,MESH*2 PRSTRS ESEL,ELEM,3,EMAX,MESH*2 PRSTRS ESEL,ELEM,MESH,EMAX,MESH*2 PRSTRS EALL NALL NSEL,NODE,1,481,16 PRNSTR NSEL,NODE,4,484,16 PRNSTR NSEL,NODE,7,487,16 PRNSTR EALL NALL • DEFINE STRAINS * PRINT STRAINS FOR RADIAL NERVE * PRINT STRAINS FOR MUSCULO NERVE * PRINT STRAINS FOR MEDIAN AND ULNAR NERVES * PRINT STRESSES FOR RADIAL NERVE * PRINT STRESSES FOR MUSCULO NERVE * PRINT STRESSES FOR MEDIAN AND ULNAR NERVES C*** C*** ROOT FILE TO SET THE PARAMETERS OF THE C*** NON HOMOGENEOUS LIMB COMPRESSION MODEL C*** /PREP7 •SET,PRES.2 • PRESSURE PROFILE •SET,RAD I,.05 * LIMB RADIUS •SET,CUFF,.10 • CUFF WIDTH •SET,OFFS,0.00 * OFFSET OF PRESSRE PROFILE •SET.PEAK.1 • NUMBER OF PEAKS •SET,FAT,10 * FAT CONTENT •SET,BONN,1 • BONE/MUSCLE INTERFACE SETTING •SET,SKIN,1 • SKIN/CUFF INTERFACE SETTING •SET,ENDS,0 • AXIAL ENDS SETTING •SET,MESH,7 * RADIAL MESH /INPUT,MODEL * CALL THE PROGRAM TO BUILD THE AFWRIT * COMPILE THE PROGRAM FINISH /EXE • EXECUTE THE PROGRAM /INPUT,27 FINISH /POST1 /INPUT, OUTPUT • IT PERFORM ANAL 1 SYS ON OUTPUT FINISH c*** c*** Appendix C. ANSYS PROGRAM LISTINGS ^»** *»»#** * *»* * * *»* * * * * *»* * *»* *#*»** *»»*»** * * * * * * * *»* * * * c*** C*** THIS PROGRAM CONSTRUCS THE NON HOMOGENEOUS C*** LIMB COMPRESSION MODEL C*** ET.1,25 EX,1,15000 EY,1,7500 EZ,1,15000 NUXY.1,.45 NUYZ,1,.«5 NUXZ.1..49 ET.2,61 EX,2,250000 DENS,2,1000 c*** C*** SET UP NODES AND ELEMENTS C*** C*** EDELE.ALL NDELE.ALL ECOMPR NCOMPR •SET,FAT,FAT/100 •SET,FAT,-FAT •SET.FAT.FAT+-1 •SET,FAT,FAT**0.5 •SET,FAT,-FAT •SET.FAT.FAT+1 •SET,FAT,FAT*RADI •SET,BONE,RAD1*0.30 •SET,RINC,RAD I-BONE *SET,RINC,RINC-FAT •SET.R1NC.R1NC/MESH •SET,A1NC,0.0025 *SET,MES,MESH+3 •SET,X,BONE •SET,NOD,1 •BEGIN,CONS N,NOO,X,0 NGEN,61,MES,NOD,NOD,1,,AINC *SET,NOD,NOO+1 •SET.X.X+RINC •END •DO,CONS,1,MESH,1 •SET.X.X-RINC N.NOO.X+FAT NGEN,61,MES,N0D,N0D,1,,AINC •SET.X.X+FAT N.NOD+1.X+0.001 NGEN,61,MES,NOD+1.NOD+1,1,,AINC MAT.1 TYPE,1 E,1.2,MES+2,MES+1 EGEN,MESH,1,1,1,1 EGEN,60,MES,1,MESH,1 MAT,2 TYPE,2 *SET,BB,MES+MESH E.MESH+1,MESH+2,BB+2,BB+1 *SET,ELLI,MESH*60 •SET.ELLI.ELLI+1 EGEN,60,MES,ELLI,ELLI MAT.1 TYPE.1 *SET,ELL,MESH*60 •SET.ELL.ELL+61 •SET,CC,MES*2 E,MES-1,MES,CC,CC-1 EGEN,60,MES,ELL,ELL,1 WSORT.Y CHOOSE THE ELEMENT TYPE FOR MUSCLE SET MATERIAL PROPERTIES CHOOSE THE ELEMENT TYPE FOR FAT SET MATERIAL PROPERTIES ERASE AND COMPRESS ALL NODES AND ELEMENTS CALCULATE FAT THICKNESS FROM FAT X SET PARAMETERS FOR CONSTRUCTION SET INITIAL CONDITIONS LOOP TO PLACE NODES ON MODEL • DEFINE THE MUSCLE ELEMENTS • DEFINE FATTY TISSUE ELEMENTS DEFINE THE SKIN ELEMENTS SORT THE ELEMENTS IN THE AXIAL DIRECTION Appendix C. ANSYS PROGRAM LISTINGS 243 *SET,D,COS(OMEG*H) *SET,D,CC*D *SET,D,D+DD •SET,PPRE,C+D •SET,PPRE,PPRE/2.0 •SET,PPRE,PPRE*POCC NSEL,Y.A-.001,8+.001 NRSEL.X,RADI+0.0005,RADI+0.002 PSF,0,0,RADI+0.001,PPRE *SET,A,B *SET,C,D *END *DO,CONS,1,DIV-1,1 *GO,HERE,43 •SET,A,STAR *SET,MID,CUFF/2 •SET,FACT,CUFF**-2 •SET,FACT,FACT*4 •SET,LINC,0.0025 •SET.H.O •SET,C,0 •SET,DIV,CUFF/0.005 •IF,CUFF,LT,0.15,HERE,2 *SET,DIV,DIV-2 PDELE.ALL •BEGIN,CONS •SET.B.A+LINC •SET,H,H+LINC *SET,D,MID-H *SET,D,D**2 *SET,D,D*FACT *SET,D,D**-1 •SET,D,D-1 •SET.D.-D •SET,D,EXP(D) •SET,D,D-1 •SET,D,-D •SET,PPRE,C+D •SET,PPRE,PPRE/2.0 •SET,PPRE,PPRE*POCC NSEL,Y,A-.001,B+.001 NRSEL.X,RAD1+0.0005,RADI+0.002 PSF,0,0,RADI+0.001,PPRE *SET,A,B •SET.C.D •END *DO,CONS,1,DIV-2,1 NALL EALL •IF,CUFF,LT,0.15,HERE,2 •SET,LINC,LINC*3 •SET,MIN,-LINC *SET,M!N,MIN+.149 NSEL,Y,MIN,0.151 NRSEL.X,RADI+0.0005,RADI+0.002 PSF,0,0,RADI+0.001,POCC NALL EALL C*** C*** C*** END OF PROGRAM C*** END SINUSOIDAL LOOP • SET INITIAL CONDITIONS FOR * EXPONENTIAL P.D. * BEGIN EXPONENTIAL LOOP END EXPONENTIAL LOOP * SET MIDDLE VALUES TO PMAX * FOR EXP. P.D. Appendix C. ANSYS PROGRAM LISTINGS c*** C*** SET THE BOUNDARY CONDITIONS C*** C*** •SET,STAR,-CUFF/2 *SET,STAR,STAR+0.15 •IF,SKIN,EQ,0,HERE,10 NSEL,X.RADl+0.0005,RAD 1+0.002 DDELE.ALL NRSEL.Y,STAR-0.001,0.151 D.ALL.UY.O NALL EALL •GO,HERE,5 NSEL.X,RADI+O.0005,RADI+O.002 DDELE.ALL NALL EALL •IF,BONN,EQ,0,HERE,7 NSEL.X,BONE,BONE D.ALL.UX.O D,ALL,UY,0 NALL EALL •GO,HERE,6 NSEL.X,BONE,BONE DDELE.ALL D,ALL,UX,0 NALL EALL •IF,ENDS,EQ.O,HERE,5 NSEL,Y,0,0 D.ALL.UY.O NALL EALL NSEL,Y,0.15,0.15 D.ALL.UY.O NALL EALL C*** C*** C*** SET THE PRESSURE DISTRIBUTION C*** C*** •SET,CIRC,RAD1*6.283185308 •SET,POCC,CIRC*16 •SET,POCC,POCC/CUFF •SET,POCC,POCC*133.0 •SET,POCC,POCC+10000.0 •IF,PRES,EQ,2,HERE,8 *IF,PRES,EO,3,HERE,37 PDELE.ALL NSEL,Y,STAR-0.001,0.151 NRSEL.X,RADI+O.0005.RADI+O.002 ENODE PSF,0,0,RADI+O.001,POCC •GO,HERE,73 •SET,A,STAR *SET,OMEG,CUFF**-1 *SET,OMEG,OMEG*PEAK •SET,OMEG, OMEG*6.2832 •SET,LINC,0.0025 •SET,H,0 •SET.C.OFFS •SET,CC,OFFS-1.0 •SET.CC.CC/2.0 •SET.DD.OFFS+1.0 •SET.DD.DD/2.0 •SET.DIV.CUFF/0.005 PDELE.ALL •BEGIN,CONS •SET.B.A+LINC •SET.H.H+LINC SET B.C. FOR CUFF/SKIN INTERFACE SKIN=0 : FREE TO SLIDE AXIALLY SKIN=1 : RESTRAINED SET B.C. FOR BONE/MUSCLE INTERFACE BONN=0 : FREE TO SLIDE AXIALLY B0NN=1 : RESTRAINED SET B.C. FOR END OF MODEL ENDS=0 : FREE TO EXPAND AXIALLY ENDS=1 : RESTRAINED SET B.C. AT SYMMETRY AXIS CALCULATE OCCLUSION PRESSURE USING CUFF WIDTH AND LIMB RADIUS SET THE PRESSURE DISTRIBUTION PRES=1 : RECTANGULAR P.D. PRES=2 : SINUSOIDAL P.D. PRES=3 : EXPONENTIAL P.D. • SET RECTANGULAR P.D. <** SET INITIAL CONDITIONS FOR SINUSOIDAL P.D. * BEGIN SINUSOIDAL LOOP Appendix C. ANSYS PROGRAM LISTINGS 245 c*** C*** THIS PROGRAM PRODUCES THE OUTPUT FROM THE C*** NON HOMOGENEOUS LIMB COMPRESSION MODEL C*** C*** STRESS,EX,25,37 STRESS,EY,25,38 STRESS,EZ,25,39 STRESS,EXY,25,40 SET,1,1 *SET,EMAX,MESH*60 ESEL.ELEM,1,EMAX,MESH*2 PRSTRS ESEL,ELEM,3,EMAX,MESH*2 PRSTRS ESEL,ELEM,MESH,EMAX,MESH*2 PRSTRS EALL NALL NSEL,NODE,1,601,20 PRNSTR NSEL,NODE,4,604,20 PRNSTR NSEL,NODE,7,607,20 PRNSTR EALL NALL DEFINE STRAINS PRINT STRAINS FOR RADIAL NERVE PRINT STRAINS FOR MUSCULO NERVES PRINT STRAINS FOR MEDIAN AND ULNAR NERVES PRINT STRESSES FOR RADIAL NERVE PRINT STRESSES FOR MUSCULO NERVE PRINT STRESSES FOR MEDIAN AND ULNAR NERVES C*** C*** ROOT FILE TO SET THE PARAMETERS OF C*** FULL ARTERY SECTION MODEL C*** /PREP7 /TITLE ARTERY SECTION - ***** *SET,PRES,3 * *SET,PMAX,10000 * *SET,RAD1,.00265 * *SET,THIC,0.0005 * •SET,CUFF,.10 * *SET,OFFS,0.00 * *SET,PEAK,1 * *SET,ENDS,0 * /INPUT,MODEL * AFWRIT * FINISH /EXE /INPUT,27 FINISH THE SET THE PRESSURE DISTRIBUTION SET MAXIMUM PRESSURE LEVEL OUTER RADII OF THE ARTERY THICKNESS OF THE ARTERY WALL CUFF WIDTH OFFSET OF PRESSURE PROFILE NUMBER OF PEAKS AXIAL END SETTING CALL THE PROGRAM TO BUILD THE MODEL COMPILE THE PROGRAM • EXECUTE THE PROGRAM C*** C*** Appendix C. ANSYS PROGRAM LISTINGS g**************************************** c*** C*** THIS PROGRAM CONSTRUCTS THE FINITE C*** ELEMENT MODEL OF A FULL ARTERY C*** ET,1,45 * EX,1,200000 * EY,1,550000 EZ,1,200000 NUXY,1,.45 NUYZ.1,.45 NUXZ.1,.49 ITER,3,-1 C*** C*** C*** SET UP NODES AND ELEMENTS C*** C*** EDELE.ALL * NDELE.ALL * ECOMPR NCOMPR CSYS,1 *SET,RINC,THIC/2 * *SET,AINC,15 * •SET,LINC,0.0025 •SET,X,RADI-THIC • N.1.X.0 NGEN,3,1,1,1,1,RINC * NGEN,25,3,1,3,1,,AINC NGEN,61,75,1,75,1,,,LINC E,1,2,5,4,22,23,26,25 EGEN,2,1,1,1,1 EGEN,24,3,1,2,1 EGEN,60,75,1,48,1 WSORT.Z * £*** * c*** C*** SET THE BOUNDARY CONDITIONS C*** C*** CSYS.O • NSEL.X,0,0 * D.ALL.UX.O NSEL,Y,0,0 D.ALL.UY.O NSEL,Z,0,0 D,ALL,UZ,0 NALL EALL NSEL,Z,0.15,0.15 • •IF,ENDS,EQ.O,HERE,11 * •IF,ENDS,EQ,I.HERE,9 •IF,ENDS,EQ,2,HERE,5 D,ALL,UX,0 D,ALL,UY,0 D,ALL,UZ,0 •GO,HERE,5 D.ALL.UX.O D,ALL,UY,0 •GO,HERE,2 D,ALL,UZ,0 **************** CHOOSE ELEMENT TYPE SET MATERIAL PROPERTIES ERASE AND COMPRESS ALL NODES AND ELEMENTS SET PARAMETERS FOR * CONSTRUCTION * SET INITIAL CONDITIONS * PLACE NODES ON MOOEL * PLACE ELEMENTS ON MODEL SORT THE ELEMENTS IN THE AXIAL DIRECTION SET B.C AT THE AXIS OF SYMMETRY SET B.C AT THE AXIAL END OF THE MODEL NALL EALL C*** C*** C*** C*** C**» CSYS, •SET, •SET, SET THE PRESSURE DISTRIBUTION 1 STAR,-CUFF/2 STAR+0.15 Appendix C. ANSYS PROGRAM LISTINGS 247 •IF,PRES.EQ,2,HERE,8 *IF,PRES,EQ,3,HERE,37 PDELE.ALL NSEL,Z,STAR-0.001,0.151 NRSEL.X,RADI+O.0005,RADI+O.002 ENODE PSF,0,0,RADI,PMAX •GO,HERE,73 •SET,A,STAR *SET,0MEG,CUFF**-1 *SET,OMEG,OMEG*PEAK •SET,OMEG,OMEG*6.2832 •SET,LINC,0.0025 *SET,H,0 *SET,C,OFFS •SET.CC.OFFS-1.0 *SET,CC,CC/2.0 •SET.DD.OFFS+1.0 *SET,DD,DD/2.0 •SET,DIV,CUFF/0.005 PDELE.ALL •BEGIN,CONS •SET.B.A+LINC •SET.H.H+LINC •SET,D,COS(OMEG*H) *SET,D,CC*D •SET.D.D+DD •SET.PPRE.C+D •SET,PPRE,PPRE/2.0 *SET,PPRE,PPRE*PMAX NSEL,Z.A-.001,B+.001 NRSEL.X,RADI,RADI PSF,0,0,RADI,PPRE •SET.A.B *SET,C,D •END *D0,C0NS,1,DIV-1,1 •GO,HERE,43 •SET,A,STAR •SET,MID,CUFF/2 •SET,FACT,CUFF**-2 •SET,FACT,FACT*4 •SET,LINC,0.0025 •SET.H.O *SET,C,0 •SET,DIV,CUFF/0.005 •IF.CUFF.LT,0.15,HERE,2 •SET,DIV,DIV-2 PDELE.ALL •BEGIN,CONS •SET.B.A+LINC •SET.H.H+LINC •SET.D.MID-H *SET,D,D**2 *SET,D,D*FACT *SET,D,D**-1 *SET,D,D-1 *SET,D,-D *SET,D,EXP(D) *SET,D,D-1 *SET,D,-D •SET,PPRE,C+D •SET,PPRE,PPRE/2.0 •SET,PPRE,PPRE*PMAX NSEL,Z,A-.001,B+.001 NRSEL.X,RADI,RADI PSF,0,0,RADI,PPRE •SET.A.B •SET.C.D •END •D0,C0NS,1,DIV-2,1 NALL EALL • SET THE PRESSURE DISTRIBUTION * PRES=1 : RECTANGULAR P.D. • PRES=2 : SINUSOIDAL P.D. * PRES=3 : EXPONENTIAL P.D. * SET RECTANGULAR P.D. * SET INITIAL CONDITIONS FOR * SINUSOIDAL P.D. BEGIN SINUSOIDAL LOOP END SINUSOIDAL LOOP SET INITIAL CONDITIONS FOR EXPONENTIAL P.D. BEGIN EXPONENTIAL LOOP • END EXPONENTIAL LOOP Appendix C. ANSYS PROGRAM LISTINGS 248 •IF,CUFF.LT,0.15,HERE,2 •SET,LINC,LINC*3 •SET,MIN,-LINC * SET MIDDLE VALUES TO PMAX •SET',MIN',MIN+.H9 * FOR EXP. P.D. NSEL,Z,MIN,0.151 NRSEL.X,RAD I,RAD I PSF,O.O.RADI,PMAX NALL EALL CSYS.O C*** C*** C*** END OF PROGRAM C*** C*** C*** C*** ROOT FILE TO SET THE PARAMETERS OF THE C*** QUARTER ARTERY SECTION MODEL C*** /PREP7 /TITLE ARTERY SECTION - ***** *SET,PRES,3 *SET,PMAX,10000 *SET,RADI,.00265 •SET,THIC,0.0005 *SET,CUFF,.10 •SET,OFFS,0.00 •SET,PEAK,1 •SET,ENDS,0 /INPUT,MODEL AFURIT FINISH /EXE /INPUT,27 FINISH c**« C*** SET PRESSURE DISTRIBUTION SET MAXIMUM PRESSURE LEVEL OUTER RADII OF THE ARTERY THICKNESS OF THE ARTERY WALL CUFF WIDTH OFFSET OF PRESSURE PROFILE NUMBER OF PEAKS AXIAL END SETTING CALL THE PROGRAM TO BUILD THE MODEL COMPILE THE PROGRAM * EXECUTE THE PROGRAM Appendix C. ANSYS PROGRAM LISTINGS CHOOSE THE ELEMENT TYPE SET MATERIAL PROPERTIES ERASE AND COMPRESS ALL NODES AND ELEMENTS SET PARAMETERS CONSTRUCTION C*** C*** THIS PROGRAM CONSTRUCTS THE FINITE C*** ELEMENT MODEL OF A QUARTER ARTERY C*** ET,1,45 EX,1,15000 EY,1,7500 EZ,1,15000 NUXY,1,-45 NUYZ,1,.45 NUXZ.1,.49 ITER,3,-1 C*** c*** C*** SET UP NODES AND ELEMENTS C*** c*** EDELE.ALL NDELE,ALL ECOMPR NCOMPR CSYS.1 *SET,RINC,THIC/2 *SET,AINC,15 •SET,LINC,0.0025 •SET,X,RADI-THIC N,1,X,0 NGEN,3,1,1,1,1,RINC NGEN,7,3,1,3,1,,AINC NGEN,61,21,1,21,1,,,LINC E,1,2,5,4,22,23,26,25 EGEN,2,1,1,1,1 EGEN,6,3,1,2,1 EGEN,60,21,1,12,1 USORT.Z C*** C*** C*** SET THE BOUNDARY CONDITIONS C*** C*** CSYS.O NSEL.X,0,0 D,ALL,UX,0 NSEL,Y,0,0 D,ALL,UY,0 NSEL,Z,0,0 D.ALL.UZ.O NALL EALL NSEL,Z,0.15,0.15 •IF,ENDS,EQ,O.HERE,11 *1F,ENDS,EQ,1,HERE,9 •IF,ENDS,EQ,2,HERE,5 D.ALL.UX.O D.ALL.UY.O D.ALL.UZ.O •GO,HERE,5 D.ALL.UX.O D.ALL.UY.O •GO,HERE,2 D.ALL.UZ.O FOR * SET INITIAL CONDITIONS * PLACE NODES ON MODEL * PLACE ELEMENTS ON MODEL SORT THE ELEMENTS IN AXIAL DIRECTION THE SET B.C AT THE AXIS OF SYMMETRY SET B.C AT THE AXIAL END OF THE MODEL NALL EALL C*** C*** £*** c*** CSYS •SET •SET SET THE PRESSURE DISTRIBUTION ,1 .STAR,-CUFF/2 .STAR+0.15 Appendix C ANSYS PROGRAM LISTINGS 250 *IF,PRES,EQ,2,HERE,8 *1F,PRES,EQ,3,HERE,37 PDELE.ALL NSEL.Z,STAR-0.001,0.151 NRSEL.X,RAD 1+0.0005,RADI+0.002 ENODE PSF,0,0,RAD1,PMAX *G0,HERE,73 •SET,A,STAR •SET,OMEG,CUFF**-1 •SET,OMEG,OMEG*PEAK •SET,OMEG,OMEG*6.2832 •SET,LINC,0.0025 *SET,H,0 •SET.C.OFFS *SET,CC,OFFS-1.0 *SET,CC,CC/2.0 *SET,DD,OFFS+1.0 *SET,DD,DD/2.0 •SET,DIV,CUFF/0.005 PDELE.ALL •BEGIN,CONS •SET.B.A+LINC •SET.H.H+LINC •SET,D,COS(OMEG*H) •SET,D,CC*D *SET,D,D+DD •SET,PPRE,C+D •SET,PPRE,PPRE/2.0 •SET,PPRE,PPRE*PMAX NSEL,Z.A-.001,B+.001 NRSEL.X,RADI.RADI PSF,0,0,RADI,PPRE •SET.A.B •SET.C.D •END •DO,CONS,1,DIV-1,1 •GO,HERE,43 •SET,A,STAR •SET,MID,CUFF/2 •SET,FACT,CUFF**-2 •SET,FACT,FACT*4 •SET,LINC,0.0025 •SET.H.O •SET,C.O •SET.DIV,CUFF/0.005 •IF,CUFF,LT,0.15,HERE,2 •SET,DIV,DIV-2 PDELE.ALL •BEGIN,CONS •SET.B.A+LINC •SET.H.H+LINC •SET.D.MID-H •SET,D,0**2 •SET,D,D*FACT *SET,D,D**-1 *SET,D,D-1 •SET.D.-D *SET,D,EXP(D) •SET.D.D-1 *SET,D,-D •SET,PPRE,C+D *SET,PPRE,PPRE/2.0 •SET,PPRE,PPRE*PMAX NSEL,Z.A-.001,B+.001 NRSEL.X,RAD I,RAD I PSF,O.O.RADI,PPRE •SET.A.B •SET.C.D •END *D0,CONS.1,DIV-2,1 NALL EALL * SET THE PRESSURE DISTRIBUTION * PRES=1 : RECTANGULAR P.D. * PRES=2 : SINUSOIDAL P.D. * PRES=3 : EXPONENTIAL P.D. * SET RECTANGULAR P.D. * SET INITIAL CONDITIONS * SINUSOIDAL P.D. FOR BEGIN SINUSOIDAL LOOP * END SINUSOIDAL LOOP * SET INITIAL CONDITIONS FOR * EXPONENTIAL P.D. * BEGIN EXPONENTIAL LOOP END EXPONENTIAL LOOP Appendix C. ANSYS PROGRAM LISTINGS *IF,CUFF.LT,0.15,HERE,2 •SET,LINC,L1NC*3 •SET,MIN,-LINC •SET,MIN,MIN+.149 NSEL,Z,MIN,0.151 NRSEL.X,RADI.RADI PSF,0,0,RAD I,PMAX NALL EALL CSYS.O C*** C*** C*** END OF PROGRAM C*** C*** SET MIDDLE VALUES TO PMAX FOR EXP. P.D. Appendix D THICK-WALLED CYLINDER THEORY The radial and circumferential stress profiles in a thick-walled cylinder are developed in accordance with the imposed boundary conditions and material properties associated with the limb compression phenomenon. Figure D.l shows the thick-walled cylinder model under limb compression constraints. Figure D.l: Thick-walled cylinder under limb compression constraints [50] The material properties were set as described in Chapter 3: Er=Ee = 15000 Pa Ez = 7500 Pa vTZ = vBt = 0.45 Vr6 = 0.49 (D.l) 252 Appendix D. THICK-WALLED CYLINDER THEORY 253 The boundary and loading conditions were set as follows: aT = —P0 at r = b ee = 0 at r = a Figure D.2 shows the free body diagram of a half-annulus of thickness dr. (D.2) a dr c dr Figure D.2: Free body diagram of a selected annulus [50] The resulting equilibrium equation follows: 2aedr + 2arr - 2(aT + dar)(r + dr) = 0 (D.3) By simplifying and neglecting higher order terms, Equation D.4 is obtained. a e - c T - r^- = 0 (D.4) dr By imposing a constant longitudinal strain along the full section of the cylinder the following relationship is established: E-' —ET - sr (D-6) Since the material properties impose that Eg = ET = E, and that ugt = vTZ = u, it follows that: Et = ag + aT = 2Ci C\\ = a constant (D.6) Appendix D. THICK-WALLED CYLINDER THEORY 254 By combining Equations D.4 and D.6 the following relationship is found: Multiplying each side by r: And noting that: r^+2ar=2C1 (D.7) ar r 2^- + 2rar = 2 r d (D.8) dr d(r 2aT) 2 = r 2dardr + 2raT (D.9) dr By combining Equations D.8 and D.9, Equation D.10 results. d{r 2aT) = 2rC1dr (D.10) Performing the integration results in these simplified relationships: r2cr r = r2C\\ + Ci Ci : integration constant (D.ll) a-e = 2c7x - X R : Limb Radius Y All simulations performed on the limb compression models are described in the tables of this Appendix. Tables E.2 through E.9 show all simulations performed under simple tourniquet configurations, whereas Tables E.10 to E.12 show the simulations performed under Esmarch/tourniquet configurations. It should be noted that only two variables at a time are investigated while the others are held constant at their respective default value (listed below). In order to reduce the number of tables, the first three letters of the code names appear in the titles. Parameter default values : Pressure Profile Sinusoidal Boundaries RRF Offset 0.0 Peaks 1 Cuff Width 10 cm Limb Radius 50 mm Fat Content 10 % Appendix E. LIMB COMPRESSION MODEL SIMULATIONS 258 Table E.2: Cuff width vs limb radius ( H O N & N O N ) Limb Radius (mm) Cuff Width (cm) 2.5 5.0 7.5 10.0 12.5 15.0 17.5 20.0 30 WR13 WR23 WR33 WR43 WR53 WR63 WR73 WR83 40 WR14 WR24 WR34 WR44 WR54 WR64 WR74 WR84 50 WR15 WR25 WR35 WR45 WR55 WR65 WR75 WR85 60 WR16 WR26 WR36 WR46 WR56 WR66 WR76 WR86 70 WR17 WR27 WR37 WR47 WR57 WR67 WR77 WR87 Appendix E. LIMB COMPRESSION MODEL SIMULATIONS 259 Table E.3: Cuff width vs pressure profile ( H O N & N O N ) Profile Cuff Width (cm) 2.5 5.0 7.5 10.0 12.5 15.0 17.5 20.0 Sin WP1S WP2S WP3S WP4S WP5S WP6S WP7S WP8S Exp WP1E WP2E WP3E WP4E WP5E WP6E WP7E WP8E Rec WP1R WP2R WP3R WP4R WP5R WP6R WP7R WP8R Appendix E. LIMB COMPRESSION MODEL SIMULATIONS Table E.4. Limb radius vs pressure profile ( H O N & N O N ) Profile Limb Radius mm) 30 40 50 60 70 Sin Exp Rec LP3S LP3E LP3R LP4S LP4E LP4R LP5S LP5E LP5R LP6S LP6E LP6R LP7S LP7E LP7R Appendix E. LIMB COMPRESSION MODEL SIMULATIONS 261 Table E.5: Offset vs peaks ( H O N & N O N ) Peaks Offset 0.0 0.2 0.4 0.6 0.8 1.0 1 ON01 ON21 ON41 ON61 ON81 ONT1 2 ON02 ON22 ON42 ON62 ON82 ONT2 3 ON03 ON23 ON43 ON63 ON83 ONT3 4 ON04 ON24 ON44 ON64 ON84 ONT4 Appendix E. LIMB COMPRESSION MODEL SIMULATIONS 262 Table E.6: Cuff width vs fat content (NON) Fat Content (%) Cuff Width (cm) 2.5 5.0 7.5 10.0 12.5 15.0 17.5 20.0 5.0 WF11 WF21 WF31 WF41 WF51 WF61 WF71 WF81 10.0 WF12 WF22 WF32 WF42 WF52 WF62 WF72 WF82 15.0 WF13 WF23 WF33 WF43 WF53 WF63 WF73 WF83 20.0 WF14 WF24 WF34 WF44 WF54 WF64 WF74 WF84 Appendix E. LIMB COMPRESSION MODEL SIMULATIONS 263 Table E.7: Fat content vs limb radius ( N O N ) Limb Radius (mm) Fat Content (%) 5.0 10.0 15.0 20.0 30 FR13 FR23 FR33 FR43 40 FR14 FR24 FR34 FR44 50 FR15 FR25 FR35 FR45 60 FR16 FR26 FR36 FR46 70 FR17 FR27 FR37 FR47 Appendix E. LIMB COMPRESSION MODEL SIMULATIONS 264 Table E.8: Fat content vs pressure profile ( N O N ) Profile (mm) Fat Content (%) 5.0 10.0 15.0 20.0 Sin FR1S FR2S FR3S FR4S Exp FR1E FR2E FR3E FR4E Rec FR1R FR2R FR3R FR4R Appendix E. LIMB COMPRESSION MODEL SIMULATIONS 265 Table E.9: Boundary conditions (HON & NON) Bone/Muscle Skin/CufF Axial Ends Code F F F B C F F F F F R B C F F R F R F B C F R F F R R B C F R R R F F B C R F F R F R B C R F R R R F B C R R F R R R B C R R R Appendix E. LIMB COMPRESSION MODEL SIMULATIONS Table E.10: Esmarch overlap vs Esmarch width ( H O E & N O E ) Width (mm) Overlap 0.0 0.25 0.5 0.75 1.0 20 UV02 UV12 UV22 UV32 UV42 30 UV03 UV13 UV23 UV33 UV43 40 UV04 UV14 UV24 UV34 UV44 50 UV05 UV15 UV25 UV35 UV45 Appendix E. LIMB COMPRESSION MODEL SIMULATIONS 267 Table E l l : Esmarch overlap vs Esmarch pressure ( H O E & N O E ) Pressure (%) Overlap 0.0 0.25 0.5 0.75 1.0 10 UE01 UE11 UE21 UE31 UE41 20 UE02 UE12 UE22 UE32 UE42 30 UE03 UE13 UE23 UE33 UE43 40 UE04 UE14 UE24 UE34 UE44 50 UE05 UE15 UE25 UE35 UE45 Appendix E. LIMB COMPRESSION MODEL SIMULATIONS 268 Table E.12: Esmarch width vs Esmarch pressure ( H O E & N O E ) Pressure (%) Width (mm) 20 30 40 50 10 VE21 VE31 VE41 VE51 20 VE22 VE32 VE42 VE52 30 VE23 VE33 VE43 VE53 40 VE24 VE34 VE44 VE54 50 VE25 VE35 VE45 VE55 "@en ; edm:hasType "Thesis/Dissertation"@en ; edm:isShownAt "10.14288/1.0080683"@en ; dcterms:language "eng"@en ; ns0:degreeDiscipline "Mechanical Engineering"@en ; edm:provider "Vancouver : University of British Columbia Library"@en ; dcterms:publisher "University of British Columbia"@en ; dcterms:rights "For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use."@en ; ns0:scholarLevel "Graduate"@en ; dcterms:title "A biomechanical analysis of limb compression induced by pneumatic surgical tourniquets"@en ; dcterms:type "Text"@en ; ns0:identifierURI "http://hdl.handle.net/2429/27828"@en .