Systems and methods for prevention of set screw loosening
AssigneeNexus Spine, LLC
InventorsDavid T. Hawkes, Peter A. Halverson
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Abstract
Implementations of the disclosed systems and methods include medical implants, such as spinal implants for posterior fixation. According to some implementations, the implant includes a tulip configured to receive a rod, along with a set screw configured to fix the rod in place within the tulip. In some cases, the set screw is configured to selectively rotate in a first direction to tighten and to selectively counter-rotate in a second direction to loosen. According to some implementations, the implant includes a mechanical stop configured to prevent undesirable counter-rotation of the set screw to thereby resist loosening of the set screw. Other implementations are discussed.
Claims20
A spinal implant for posterior fixation comprising:
- an anchor;
- a rod;
- a tulip comprising:
- a bottom having an opening, the opening being configured to receive the anchor;
- a top;
- and
- a receptacle disposed between the bottom and the top, the receptacle being configured to receive the rod and comprising complimentary threading;
- and
- a set screw comprising a threading configured to interface with the complementary threading of the receptacle, the set screw being configured to prevent the rod from withdrawing from the receptacle through the top of the tulip when the set screw is in place,
- wherein the set screw further comprises a mechanical stop configured to resist counter-rotation of the set screw when the set screw is in place to thereby resist loosening of the set screw.
A set screw for a spinal implant, the set screw comprising:
- threading configured to interface with complementary threading of the spinal implant to allow for rotation of the set screw in a tightening direction and counter-rotation in a loosening direction;
- and
- a mechanical stop configured to create a local energy minimum in a potential energy curve of the set screw to counteract a natural tendency of the set screw to counter-rotate from a higher potential energy state to a lower potential energy state, thereby resisting the counter-rotation of the set screw, and thereby resisting loosening of the set screw.
A method of providing a spinal implant having a set screw configured to resist loosening, the method comprising:
- obtaining a set screw comprising threading and a mechanical stop;
- obtaining an anchor;
- obtaining a rod;
- obtaining a tulip comprising a bottom, a top, and a receptacle;
- disposing the anchor through an opening of the bottom of the tulip;
- disposing the rod within the receptacle of the tulip;
- rotating the set screw into the top of the tulip such that the threading of the set screw engages with a complementary threading of the tulip, thereby causing the set screw to tighten;
- and
- engaging the mechanical stop to resist counter-rotation of the set screw, thereby resisting loosening of the set screw.
Dependencies are inferred from the claim text.