BME 301: Vertebroplasty

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BME 301 Vertebroplasty
Enhancing Force Generation A Syringe Modification
Mid-semester
Presentation March 07, 2003 Client Dr. Mike
Tuite Advisor Glennys Mensing Bayley
Denham, Mike Kosir, Mike Wells, Kelly Williams
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Overview

• The Vertebroplasty Procedure
• The Design Problem
• Properties of Polymethylmethacrylate (PMMA)
• The Design Options
• Decision Matrix and Conclusions

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Vertebroplasty The Procedure

• Relatively New Procedure
• Uses PMMA, Bone Cement
• Used to Reduce Spinal Fracture Pain
• Performed Outpatient, Easy
• Recovery in Less than 48 Hours

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Problem Statement

• Simplify the Current Procedure
• Device to Generate Force in a Syringe
• Force Must Empty 10cc Syringe
• High Viscosity Material, PMMA
• Must Comply with Current Procedure

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The Material PMMA
Akroyd J. and Kraft M., BASF

• Polymer Powder and Monomer Liquid
• Monomer Emits Noxious Vapors
• Polymerization Reaction
• Exothermic and Increasing Viscosity
• Properties Limit Procedure lt 10 minutes

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PMMA and Pressure Considerations

• Polymer must be Dispensed from 11-13 Gauge Needle
• Wall Shear Stress Creates Retarding Force
• Pressure Magnitude Unknown
• Hand Strength Estimation
• Experiment to Define Pressure Drop

PMMA
Needle (11-13 Gauge)
Syringe
http//www.rz.uni-frankfurt.de/weltner/Mis6/mis6.
html
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Design 1 Using Levers to Generate Force
F1
F2

• Equation for a Lever F1D1 F2D2

D1
D2

• Advantages
• Easy to Use and Maintain
• Meets Sterility Requirements
• Light Weight
• Can Fit Any Size Syringe

• Disadvantages
• Similar Model in Production
• Front Heavy, Hinders Procedure
• May not Generate Proper Force

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Design 1 Using Levers to Generate Force
Plunger
Ratchet
PMMA
Spring
Lever
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Design 2 Using Hydraulic Force

• Equation for Hydraulics F1/A1 F2/A2

F2
F1
A2
A1
http//www.howstuffworks.com/pulley1.htm

• Advantages
• Meets Sterility Requirements
• Large Force Increase
• Can be used in Combination with Other Systems

• Disadvantages
• May not be Light Weight
• May be Difficult to Maintain
• May be Difficult to Operate

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Design 2 Using Hydraulic Force
Plunger
Plunger
Fluid
PMMA
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Design 3 Using Electrical Power to Generate Force

• Equation Dependent Upon Torque

• Advantages
• Novel Idea
• Consistent
• Easy to Use
• Large Force Generation

• Disadvantages
• May not be Light Weight
• May be Difficult to Sterilize
• Power Supply Issues

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Design 3 Using Electrical Power to Generate Force
Syringe Attachment
Syringe
Device
Motor
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Decision Matrix
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Conclusions

• Current Procedure Needs Modification
• Ability to use 10cc Syringe
• All Three Devices Present Feasible Solutions
• Further Research into Pressure Drop
• Further Research into Sterilization of Materials

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Questions?
http//www.spine-surgery.com/Procedures/holt/Defau
lt.htm
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Acknowledgements

• Dr. Michael Tuite
• Glennys Mensing
• Mitch Tyler
• Dan Klingenberg
• Parallax Medical
• Biomet Merck

http//www.biometmerck.com/english/products/index.
htm