Pedicle Screw Taper Lock for Conical Range of Motion

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Solution Overview

Problem

Current spinal alignment systems, particularly posterior pedicle screw constructs, face limitations in range of motion and are complex, unreliable, and difficult to manipulate, which restricts optimal alignment with vertebrae.

Innovation Solution

A pedicle screw construct featuring a coupling with a collet and a pedicle screw having a shank, head, and neck, allowing for a conical range of motion between 70° and 95°, facilitated by beveled lips on the coupling and collet, and a U-shaped saddle configuration for accommodating rods of varying diameters, enabling smooth angular displacement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If current posterior pedicle screw systems are used, then spinal alignment can be achieved, but the range of motion is limited and the systems are complex and difficult to manipulate

Engineering Contradiction:
Improverange of motionVSAvoidsystem complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The coupling device is divided into distinct functional components: a body portion for structural support, a collet for securing the rod, and a saddle for rod accommodation. This segmentation allows each component to be optimized independently while maintaining overall system functionality and reducing complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The coupling device incorporates a tapered bore with a range of motion of at least 70 degrees, allowing dynamic adjustment of the pedicle screw angle relative to the coupling body. This dynamic capability enables the system to adapt to various spinal alignment requirements without increasing overall device complexity.

Inventive Principle:
Principle #15Dynamics

2Stability of the object's composition

If the pedicle screw head diameter is increased for stability, then interference with the collet and coupling increases, reducing range of motion

Engineering Contradiction:
Improvescrew stabilityVSAvoidrange of motion
Core Design Contradiction:
Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The coupling device provides angular adjustment capability in a different dimensional space (rotational/conical movement) rather than linear displacement. This allows the pedicle screw to achieve proper alignment through angular orientation rather than requiring larger head dimensions for positional adjustment.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The system changes the parameter of angular orientation through the tapered bore mechanism, allowing the pedicle screw to be positioned at various angles (at least 70 degrees range) without changing the physical dimensions of the screw head, thus avoiding interference with the collet and coupling structures.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2222238B1Posterior pedicle screw having a taper lock
Publication Date: 2016.02.24 K2M INC
  • EP2222238B1 patent drawingFigure 1A~1C
  • EP2222238B1 patent drawingFigure 2A~2B
  • EP2222238B1 patent drawingFigure 3A~3B

AI summary

A pedicle screw construct includes a pedicle screw, a coupling, and a collet. The pedicle screw includes a shank having a helical thread formed thereon and a head at one end. The collet is positioned atop the head of the pedicle screw. The collet and pedicle screw are inserted into the coupling. The pedicle screw is rotatable and pivotable relative to the collet and coupling assembly. The collet and the coupling each have a saddle that is adapted and configured for receiving a rod member.