Transcript Final Presentation

Corneal Membrane Transplant Injector
Kristen Berger
Paul Bieniek
David Brooks
Marie Gill
Dr. Ahmed Al-Ghoul
April 13, 2007
Cornea Surgery
• Keratoplasty is used to treat
many cornea diseases
• 2005 – Over 100,000
surgeries performed in U.S.
• More efficient surgical
techniques have recently
evolved (DSEK)
http://sarajdoktor.blogger.ba/
Current Surgery Techniques: DSEK
• 50% of keratoplasty
procedures
• Advantages
• Only replaces diseased tissue
• Smaller incision
• Fewer stitches
• Disadvantages
• Donor tissue folded and
inserted
• Damage to endothelial cells
• Interface haze
• Loss of intraocular pressure
Gorovoy, M. S., Francis, W. P.
Eye Anatomy
Design Objectives
• Safely deliver donor tissue to anterior chamber
• Minimize contact with endothelium
• Reduce incision size (<4mm)
• Maintain intraocular pressure
Requirements
• Compatible with existing equipment
• Functions:
• Irrigation
• Aspiration
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Easy to operate
Sterilizable
Biocompatible
Life in service - 5 years at 5
procedures/week
Competitive Analysis
• Currently, no device
performs the same
function
• Similar devices
• Irrigation/ aspiration
devices
• Lens implant devices
http://www.hsc.wvu.edu/som/eye/servicesCataract.asp
Design Alternatives
1.)
• Curled membrane
• Translatable suction
platform
• Too much friction
2.)
• Wrapped membrane
• Translatable oval
suction tip
• Triple lumen design
Design – End of First Semester
• Three component system
• Stainless steel injector
• Clear plastic cartridge
• Stainless steel case
• Fabrication
• “If you guys think you can make
this, you’re crazy!” – Andy Holmes
• Injector too complex to be machined as one piece
Redesign Issues
• Design for Production – Consider Assembly
• Vacuum and irrigation tubes; luer fittings
• Simplification
• Merging of case and cartridge
Prototype Fabrication
• Cartridge – SLA
• Injector parts
• Stainless steel, SLA, PVC
• Used lathe and mill
• Hand-assembled
Features
Luer fittings for attachment to
emulsifier
O-rings for water-tight seal
between parts
Ergonomic grips
Pin and guidance track to allow
precise alignment of parts
Surgical grade stainless
steel for injector
Clear plastic cartridge for
visualization during use
Potential Hazards
• Damage to donor
endothelial cells
Category III
• Inability to maintain the
anterior chamber
Category III
• Failure to achieve suction
Category III
• Negative reaction of tissue
to the device
Category IV
• Damage to patient’s eye
Category IV
Severity:
Category
Category
Category
Category
I - Catastrophic
II - Critical
III - Marginal
IV - Minor
Concept Model
• Testing of suction and irrigation on silicone corneas
and contact lenses
Preliminary Prototype Testing
• Test functions:
• Suction
• Irrigation
Future Prototype Testing
• Qualitative using animal cadaver eyes
• Ease of use - ergonomics
• Function
• Works with phacoemulsification machine
• Holds corneal membrane on injector
• Maintains anterior chamber pressure
• Safely transports the corneal membrane
• Histology testing of corneal membrane and recipient eye
Qualitative Testing Matrix
Prototype
Feature
Ease of use/
ergonomics
Needed incision
size
Attaches
corneal
membrane
properly
Maintains
anterior
chamber
pressure
Corneal
transplant
procedure time
Poor
Fair
Marginal
Good
Excellent
FDA – Classification I
Similar Devices:
Intraocular lens guide
• 21 CFR 886.4300
• “… a device intended to be inserted into the eye during
surgery to direct the insertion of an intraocular lens
and be removed after insertion is completed.”
Ocular surgery irrigation device
• 21 CFR 886.4360
• A device used “… during ophthalmic surgery to deliver
continuous, controlled irrigation to the surgical field.”
FDA – Classification I
• General Characteristics
• Non-life sustaining
• Least complicated
• Failure poses little risk
• Premarketing submission 510(k)
• Substantially equivalent to a legally marketed device not
subject to a premarket approval (PMA)
• Intraocular lens guide is exempt from 510(k) unless “ . . .
if used as folders and injectors for soft or foldable IOL's.”
FDA – Classification I
• General Controls:
• Quality assurance program
• Suitable for intended use
• Adequately packaged
• Properly labeled
• Establishment registration
• Device listing forms
Economic Considerations
• Cartridge
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~50,000 DSEK procedures per year in US
$1.10/cartridge production cost1
Injection mold: $15,000-25,0002
ABS: $2.00/lb2
Revenue = ($100 – $1.10)*50,000 = $5M per year
• Injector
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~2,500 Hospitals and Surgery Centers
$100/injector3 (CNC)
$20/injector4 (MIM)
Injection mold: $25,0004
Revenue = ($1500 - $20)*(2,500 hospitals)*(3 units/hospital)/(5 yrs)
= $2.2M per year
1) http://www.geplastics.com/gep/eng/webted/webted.html
2) http://kazmer.uml.edu/Software/JavaCost/index.htm
3)http://www.jobshoptechnology.com/features/0302/mim.shtml
4) http://news.thomasnet.com/IMT/archives/2004/05/the_benefits_of.html?t=archive
Project Management
Sept.
Oct.
Nov.
Dec.
Jan.
Feb.
Mar.
Apr.
May
Initial Research and Design
Proof of Concept
Concept proved
2/8/07
Redesign
Fabrication
Prototype
Completed
4/6/07
Prototype Testing
Team Contributions
• Dave – Initial SolidWorks design, background
research
• Paul – Initial SolidWorks design, cartridge
development, fabrication
• Marie – Concept model testing, preliminary
prototype testing, FDA regulatory research
• Kristen – SolidWorks redesign, injector
development and fabrication
• All – DHF and SBIR
Future Directions
• Biocompatibility Testing
• Plastic tip redesign
• Decrease size
• Conduct stress tests
• Make tip slanted
• Durability Testing
• Upscale to mass production
Acknowledgements
• Dr. Ahmed Al-Ghoul
• Andy Holmes
• Generous gift of Drs. Hal Wrigley and Linda Baker
• Department of Bioengineering
Thank You!
• Questions?