Project of a medical device to support the diagnosis of the ankle pathologies

Transcription

1 Project of a medical device to support the diagnosis of the ankle pathologies Rita Ferreira, February 6, 2015 Filipe Samuel Silva Paulo Flores MicroElectroMechanical Systems Centre University of Minho DEM Clínica do Dragão Espregueira Mendes Sports Centre FIFA Medical Centre of Excellence

2 Summary CHAPTERS Motivation How the project starts The ankle joint Anatomical characterization Cinesiological characterization The main pathologies Design of the new device Development phase Conceptual phase Final solution analysis Manufacturing process Estimated cost analysis Conclusion Further work Mechanical Engineering Department, University of Minho 22

3 Motivation The pathologies of the ankle joint are the diseases with higher impact in life quality of the patients during the execution of basic daily activities. CASES ADMITTED IN EMERGENCY SERVICE 10% MUSCULOSKELETIC SYSTEM 25% TOTALITY OF ANKLE INJURIES 50% ANKLE SPRAIN ANKLE SPRAIN RUPTURE LIGAMENT The diagnosis process of the articular injuries is based in the execution of a physical and imaging exam at different time slots. Mechanical Engineering Department, University of Minho 33

4 The ankle joint LOCATIZATION FUNCTION body weight support (with a minimum spent of energy by muscles) locomotion (moving of the body on space) To move the body is necessary a simultaneous interaction of all joint movements to position the foot at the floor and move the body over its support, the feet. Mechanical Engineering Department, University of Minho 44

5 The ankle joint ANATOMICAL CHARACTERIZATION MUSCULOSKELETAL SYSTEM Skeletal system Articular system Muscular system (bones and cartilages) (joints and ligaments) (muscles and tendons) JOINTS It is a set of bones that develop relative movements (according its degrees of freedom) or which are dynamically limited by passive stabilization elements, the ligaments. Mechanical Engineering Department, University of Minho 55

6 The ankle joint CINESIOLOGY MOVEMENTS THAT ARE INVOLVED IN FUNCTIONAL CAPACITY ROTATION Sagittal plane (transversal axis) Frontal plane (sagittal axis) Transverse plane (longitudinal axis) Flexion and extension Inversion and eversion Lateral and medial rotation TRANSLATION Sagittal axis Anterior and posterior translation Mechanical Engineering Department, University of Minho 66

7 The ankle joint CINESIOLOGY TRANSVERSAL PLANE The rotational movement consists in the rotation of the lower limb (knee extension) or of the leg (knee flexion) around its own axis. Medial/ internal: Lateral/ external: to medial plane direction. to the opposite side. NORMAL RANGE OF MOVEMENT Knee extension Knee flexion Medial rotation Lateral rotation Mechanical Engineering Department, University of Minho 77

8 The ankle joint CINESIOLOGY FRONTAL PLANE Eversion: Rotation of the ankle plantar surface to the lateral direction. Inversion: Rotation of the ankle plantar surface to the medial direction. NORMAL RANGE OF MOVEMENT Eversion Inversion Mechanical Engineering Department, University of Minho 88

9 The ankle joint CINESIOLOGY SAGITTAL PLANE Extension: Movement of the foot relatively to the leg in anterior direction. Flexion: Movement of the foot relatively to the leg in posterior direction. NORMAL RANGE OF MOVEMENT Extension Flexion Mechanical Engineering Department, University of Minho 99

10 The ankle joint CINESIOLOGY SAGITTAL AXIS The cavities formed by the union of two or more bones of a joint allows the execution of rotational movements around a specific axis. When the existing space is greater than the desired instability in the tibiotarsal articulation can be generated. The stability can be measured by translation movement of the talus relatively to the fibula and the tibia. ANTERIOR DRAWER TEST POSTERIOR DRAWER TEST NORMAL RANGE OF MOVEMENT Translation movement 8 mm Mechanical Engineering Department, University of Minho 10

11 The ankle joint THE LEADING PATHOLOGIES LATERAL SPRAIN MEDIAL SPRAIN HIGHER ANKLE LATERAL SPRAIN ROTATION INVERSION EVERSION Physical exam Varus test Valgus test Foot rotation Imaging exam Magnetic Resonance Imaging (MRI) Computerized axial tomography (CAT) Mechanical Engineering Department, University of Minho 11

12 DEVICE MECHANICAL MICROELECTROMECHANICAL DEVELOPMENT PHASE OBJECTIVES The main objective of this work is eliminate the uncertainty that currently exists in the process of diagnosis of pathologies such as an ankle sprain, in which the affected constituents tissues like ligaments. OUTWARDNESS REPRODUCTIBILITY RIGOR Mechanical Engineering Department, University of Minho 12

13 DEVELOPMENT PHASE REQUIREMENTS Evaluate the functional capacity of ligaments of the ankle structure; Degree of importance Must be integrated into the Porto Knee Testing Device; Evaluate the existance of the articular instability; Must be used during the realization of an imaging exam; Includes an intuitive process of handling; Do not need of specialized instruction for the users; Should be applied to the whole patients. High Reduced High Mechanical Engineering Department, University of Minho 13

14 DEVELOPMENT PHASE DEMANDED REQUIREMENTS EVALUATE THE FUNCTIONAL CAPACITY OF LIGAMENTS OF THE ANKLE STRUCTURE To evaluate the ankle functional capacity the device should be able to reproduce the physical tests that are executed manually by specialists in diagnosis of this type of pathologies. Varus test Valgus test Lateral rotational movement Medial rotational movement The control of the functional range of each patient is assured by health professional that executes the exam. Varus test - example Mechanical Engineering Department, University of Minho 14

15 DEVELOPMENT PHASE DEMANDED REQUIREMENTS MUST BE INTEGRATED INTO THE PORTO KNEE TESTING DEVICE Although it can be used singly the device should assure the possibility to be associated to the PKTD Physically the device must be integrated an harmonious way with the design of the existing product. In the same way that the PKTD, it should be easily conveyed and assembled. Porto Knee Testing Device Mechanical Engineering Department, University of Minho 15

16 DEVELOPMENT PHASE DEMANDED REQUIREMENTS EVALUATE THE EXISTANCE OF THE ARTICULAR INSTABILITY The evaluation of the articular instability is assured through the execution of physical tests that reproduce the translation movement of the talus relatively to the fibula and the tibia. Anterior Drawer Test Posterior Drawer Test 28 mm 28 mm When exists a movement with higher displacement than the expected that means that that joint has mechanical instability. Anterior drawer test - example Mechanical Engineering Department, University of Minho 16

17 DEVELOPMENT PHASE DEMANDED REQUIREMENTS MUST BE USED DURING THE REALIZATION OF AN IMAGING EXAM The association of a physical and imaging exams is one of the main objectives of this project because it will allow complement the results obtained in each exam type. For the integration of a mechanical device in magnetic resonance two essential conditions must be respected: The absence of magnetic elements in the chemical composition of production material; The dimensional limitation imposed by overall dimensions of the final solution. Magnetic ressonance equipment Mechanical Engineering Department, University of Minho 17 D D - Diameter of the chamber test

18 CONCEPTUAL PHASE ASSEMBLY MODEL ON THE PORTO KNEE TESTING DEVICE CURRENT MODEL What is desired with the final model: Simple mortise; Allows the adaptation in others devices; Enables it to be employed singly. FINAL MODEL Mechanical Engineering Department, University of Minho 18

19 CONCEPTUAL PHASE MODEL OF SUPPORT AND FOOT FIXATION SOLUTION B SOLUTION C (developed solutions) What is desired with the final model: Application to right and left feet; Fixation method shouldn't have backlash or tightness; It is not necessary to support all base of the foot. Anthropometric measures: Width: 116 mm Height: 296 mm (International Organization for Standardization, 2013) Mechanical Engineering Department, University of Minho 19

20 CONCEPTUAL PHASE MODEL TO EXECUTION OF MOVEMENTS (developed solutions) What is desired with the final model: Use a clean source of energy; Direct contact with moving area; Use the lowest number of components. Anterior translation Posterior translation Mechanical Engineering Department, University of Minho 20

21 CONCEPTUAL PHASE MODEL TO EXECUTION OF MOVEMENTS (developed solutions) What is desired with the final model: Use a clean source of energy; Convert the translational movement into rotational movement; Use the lowest number of components. FINAL SOLUTION Mechanical Engineering Department, University of Minho 21

22 WRONG CORRECT MICROELECTROMECHANICAL CONCEPTUAL PHASE MODEL TO EXECUTION OF MOVEMENTS FINAL SOLUTION (developed solutions) Mechanical Engineering Department, University of Minho 22

23 ANALYSIS OF THE FINAL SOLUTION The final model is able to execute the movements: Anterior translation Posterior translation 28 mm Eversion Inversion 90 Lateral rotation Medial rotation 80 Eversion/ Inversion and Lateral/ Medial rotation Mechanical Engineering Department, University of Minho 23

24 1. neutral position 2. advanced position MICROELECTROMECHANICAL ANALYSIS OF THE FINAL SOLUTION ANTERIOR TRANSLATION Mechanical Engineering Department, University of Minho 24

25 1. neutral position 2. advanced position MICROELECTROMECHANICAL ANALYSIS OF THE FINAL SOLUTION POSTERIOR TRANSLATION Mechanical Engineering Department, University of Minho 25

26 inversion neutral position eversion MICROELECTROMECHANICAL ANALYSIS OF THE FINAL SOLUTION EVERSION AND INVERSION Starter element Pneumatic cylinder: Transmission of movement Pinion-rack: Diameter: 38,50 mm Area: 1164 mm 2 Path: 55 mm Modulus: 1,5 Diameter: 60 mm Nr. of teeths: 40 Pitch: 4,71 mm Mechanical Engineering Department, University of Minho 26

27 medial rotation neutral position lateral rotation MICROELECTROMECHANICAL ANALYSIS OF THE FINAL SOLUTION MEDIAL ROTATION AND LATERAL ROTATION Starter element Pneumatic cylinder: Transmission of movement Pinion-rack: Diameter: 38,50 mm Area: 1164 mm 2 Path: 50 mm Modulus: 3 Diameter: 30 mm Nr. of teeths: 10 Pitch: 9,42 mm Mechanical Engineering Department, University of Minho 27

28 Next stage MANUFACTURING PROCESS ESTIMATED COST ANALYSIS The costs analysis consider the consumption of raw material for each possible manufacture process that can be applied to the final solution: Cost of raw material for final solution Casting in sillicone molds 32 (20 /kg) DO NOT NEED MOLDS PRODUCTION Machining REDUCTION OF MATERIAL 74 (3,7 /kg) 0% 60% 3D Printing % 100 HAS A WASTAGE OF MATERIAL OF 71,4% DO NOT NEED ADDICTIONAL PROCESSES Mechanical Engineering Department, University of Minho 28

29 Conclusions FUTURE WORKS With this project becomes possible the introduction of a new product in the market able to allow the simultaneous execution of two different exams during the diagnosis process of an ankle joint injury. The main advantage of the ankle testing device will be the capacity of quantify the major value of angular or linear displacement associated to a specific pathology at ankle joint. The support device to could be associated to a electronic system able to execute the registration of the values of angular and linear displacement during the execution of an exam. It creates a database that will be able of categorize in an automatic and quantitative way each injury. Mechanical Engineering Department, University of Minho 29

30 Rita Ferreira, February 6, 2015 Filipe Samuel Silva Paulo Flores MicroElectroMechanical Systems Centre University of Minho DEM Clínica do Dragão Espregueira Mendes Sports Centre FIFA Medical Centre of Excellence End Thank you for your attention!