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Implant-Retained Finger Prosthesis. October 19, 2007. Client: Greg Gion Advisor: Professor Tompkins Dustin Gardner Team Leader Karen Chen Communicator Allison McArton BWIG Richard Bamberg BSAC Alex Kracht Communicator. OverView. Background Problem Statement
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Implant-Retained Finger Prosthesis October 19, 2007 Client: Greg Gion Advisor: Professor Tompkins Dustin Gardner Team Leader Karen Chen Communicator Allison McArton BWIG Richard Bamberg BSAC Alex Kracht Communicator
OverView Background Problem Statement Project Design Specification Design Alternatives Future Work
Problem Statement • Design durable and functional prosthesis substructure • Design removable and force-resistant connecting mechanism • Currently in US only slip-cover used • New international approaches include bone implants • Implants in distal terminal digit bone • Prosthesis aids increased mobility and use
Background – Prosthetic finger • Silicone elastomer, polysiloxane, slips over the amputation • Medical adhesion, vacuum • Cosmetics • Less functionality
Background – Implant-retained • In Europe, UK, Austrailia, South Africa • Osseointegration abutment • Anchor solid element & polysiloxane to abutment • Functionality, regain confidence
Background – Osseointegration • Titanium implant in rabbit bone • Dentistry fixation, maxillofacial reconstruction • Two surgeries • Implant abutment into skeleton, wound healing • Re-expose abutment, attach prosthesis • 3~6 month rehabilitation
Summary of Project Design Specification (PDS) • Function • Client Requirements • Design Requirements • Physical and Operational Characteristics • Production Characteristics • Miscellaneous
Function • A substructure and connecting mechanism • Only one method currently in the U.S • Other countries are more advanced • Increase motility and usage
Requirements • Client Requirements • New or improved attachment or substructure • Final computer simulation • Keep within budget • Design Requirements • Better functionality and durability of prosthesis
Physical and Operational Characteristics • Performance Requirements • Safety • Accuracy, reliability, and life in service • Operating environment • Ergonomics, size, and weight • Materials and Aesthetics
Production Characteristics and Miscellaneous • Quantity • Target Product Cost • Standards and Specifications • Customer • Patient-related Concerns • Competition
Design Alternatives Part I: Part II: • Terminal Bone Attachment Mechanisms • Finger Prosthesis Substructure Mechanisms
Connection DSN Alternatives Screw and Clip (DSN #1) Magnet and Clip (DSN #2) Allen Wrench (DSN #3) Reverse Screw Clip (DSN #4)
(DSN#1)- Screw n’ Clip How it works… • Spring loaded shaft in terminal end • Screw prosthesis into threaded well • Align clip segments with clip wells • Push clips inwards and prosthesis downwards • Finger prosthesis locks in position
(DSN#1)- Pros & Cons Pros • Provides a smooth, tight fit • Structurally sound and stable • Resists external shear and normal forces Cons • Hard to install shaft • Difficult to remove mechanism • Complicated construction
(DSN#2)- Magnet and Clip How it works… • Align clips, wells and magnetic poles • Push clips inwards, insert into wells • Attach magnets together and release clips • Release clips simultaneously to lock position
(DSN#2)- Pros & Cons Pros • Easy to install and remove • Simple construction • Provides a smooth fit Cons • Lower resistance to shear, normal forces • Easy to fall off • Not structurally stable
(DSN#3)- Allen Wrench How it works… • Insert terminal shaft in prosthesis shaft • Position shafts such that slots aligned • Fully insert shaft until locked position • Insert Allen wrench screw through slots • Tighten screw until firm fit achieved
(DSN#3)- Pros & Cons Pros • Provides a solid, tight fit • Relatively easy to remove • Resists external shear and normal forces Cons • Non-uniform structure, not aesthetically pleasing • Difficult to remove mechanism • Complicated construction
(DSN#4)- Reverse Screw n’ Clip How it works… • Depress buttons on prosthesis • Slide prosthesis structure over terminal end • Align bottom slots with pins • Click pins into place, release buttons
(DSN#4)- Pros & Cons Pros • Provides a smooth, tight fit • Easy to remove mechanism • Resists external shear and normal forces Cons • Hard to install terminal end mechanism • Not structurally stable (top heavy) • Very complicated construction
Substructure DSN Alternatives Spring-loaded Sac (DSN #5) Mech. Joint w/ Spring (DSN #6) Flat Piece (DSN #7) Articulation Mech. (DSN #8)
(DSN#5)- Spring-Loaded Sac How it works… • Elastic fibers hold joint in place • Each fiber resists one direction of movement • A spring maintains relaxed position
(DSN#5)- Pros & Cons Pros • Allows prosthetic to move naturally • Finger can bend while keeping some tension Cons • Less feasible to create • Could tear if enough force applied • Can’t produce much gripping force
(DSN#6)- Mech. Joint w/ Spring How it works… • Round joint keeps structure solid • Bending limits built into joint • Spring-loaded to produce some gripping force • Maintains 1 degree of freedom
(DSN#6)- Pros & Cons Pros • Allows natural movement and reaction to force • Solid construction, long-lasting • Less likely to break from external forces. Cons • Difficult to produce smaller parts • Can’t produce much gripping force
(DSN#7)- Flat Piece How it works… • Flat piece of metal • Bent at a natural angle • Flatness prevents prosthetic rotation • Fastened to bone implant • Stiff movement • Very similar to recent designs
(DSN#7)- Pros & Cons Pros • Looks natural when hand is at rest • Sturdy frame allows maximum gripping force • Least likely to allow prosthetic skin to move around Cons • Does not bend at all • Prosthetic skin sees large amount of wear and tear
(DSN#8)- Articulation Mech. How it works… • Strap connects to wrist • Strap wraps around specific points • Hand flexion will curl finger inwards • No force applied when wrist is straight
(DSN#8)- Pros & Cons Pros • Facilitates gripping power • More functional than any other design • Allows for natural finger-like movement Cons • Complex design may be impossible • Easy for things to go wrong • Strap hanging out of finger
Future Plans • Confirm design with client • Create large scale, functional prototypes • Order necessary components • Consult a hand surgeon • Test prototypes • Create computer simulations
Questions??? Thank YOU!!!!