DESIGN NAME: TiLock® Modular System
PRIMARY FUNCTION: Spinal Fixation
INSPIRATION: The design is an evolution of a ball and socket with a spherical snap ring in a conical pocket to create a 1-way capture mechanism. As the spherical head of the screw presses on the snap ring, it moves and expands inside the conical pocket allowing the screw head to be captured. When a force in the opposite direction is applied, the snap ring wedges in the conical pocket thereby preventing the screw head from disassociating. Simple design but very finely honed to meet design constraints.
UNIQUE PROPERTIES / PROJECT DESCRIPTION: Unique properties of our system include that the tulip can be attached to the screw after implantation which creates a smaller footprint allowing more room to operate, opposing angle interface set screws, break away towers on extended tulips, and reverse angle buttress threads that minimize tulip splay during final tightening.
OPERATION / FLOW / INTERACTION: The screw is inserted following standard surgical guidelines. The surgeon works around the small screw head to perform any of the necessary treatments. To finish the construct, a reamer is then placed over the head of the screw to make room for the tulip. The tulip is picked up using a specialized wand that fixedly engages the tulip preventing it from dropping inadvertently. The wand is then used to pop the tulip on the screw with minimal effort and check that it is securely attached.
PROJECT DURATION AND LOCATION: The project started in March of 2015 and was completed in April of 2018 at Genesys Spine in Austin Texas.
FITS BEST INTO CATEGORY: Medical Devices and Medical Equipment Design
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PRODUCTION / REALIZATION TECHNOLOGY: The design was conceptualized in Solidworks and 3D printed at a larger scale for functional testing. Fine tuning of the design involved several iterations using ANSYS mechanical to evaluate geometry. Once the geometry was approved, the parts were machined and tested according to ASTM 1717 and ASTM 1798. The project was restarted early on due to a request for tighter specifications but the same process was employed to yield the final product.
SPECIFICATIONS / TECHNICAL PROPERTIES: Tulips
Diameter 12.2mm
Height 16.5mm (with tabs broken)
Width 11.5mm
Variants low top, reduction top, or extended top
Screws
Lengths available: 25-60mm (up to 100mm for the 8.6mm version)(
Thread diameters: 4.5-8.5mm in 0.5 mm increments
Variants: Dual-pitch/single-lead or single pitch/single-lead, cannulated or solid
TAGS: pedicle, spine, screw, modular, Genesys
RESEARCH ABSTRACT: Genesys Spine initiates all new projects by conducting research in three main areas. We perform a review of white papers pertinent to the field of interest, conduct a MAUDE database review and research complaints as well as other available post-market surveillance, then present our findings to surgeons to gain feedback on the proposed project. Design surgeons are then formally selected based on their surgical repertoire and experience and work with our team to outline the formal design.
CHALLENGE: The most difficult aspect was designing the 1-way attachment mechanism to meet the design inputs. The screw had to be polyaxial with 60 degrees of motion, the force to attach had to be low enough that it could easily be done by hand, and the force to separate had to be high enough to lift 1000lbs. All of that while still keeping the components as small as possible.
ADDED DATE: 2018-06-29 15:33:28
TEAM MEMBERS (4) : Project manager Brian Bergeron, Designer J. Landon Gilkey, Quality lead Bill Sowers and
IMAGE CREDITS: J. Landon Gilkey
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