Flexible Drill Bit Structure for Angled Hip Joint Drilling

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Solution Overview

Problem

Minimally-invasive surgical procedures for the hip joint are challenging due to its complex geometry and limited access, making it difficult for surgeons to maneuver instruments at angles offset from the approach, particularly for drilling into bone, which is essential for treatments like labral repairs.

Innovation Solution

A flexible drill bit with a 'unibody' construction, comprising a full diameter shaft, reduced diameter shaft, and fluted cutting tip, along with an angled drill guide that uses curvature and helical coils or over-molded sheaths to maintain alignment and torque, allowing for precise angled drilling within the hip joint.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a rigid drill bit is used for drilling into bone, then drilling precision and torque transmission are improved, but the ability to navigate curved pathways and reach offset angles in the hip joint is worsened

Engineering Contradiction:
Improvedrilling precisionVSAvoidability to navigate curved pathways
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The drill bit is divided into multiple sections with different diameters: a full diameter shaft for torque transmission, a reduced diameter shaft for flexibility, and a fluted cutting tip for drilling. This segmentation allows each section to serve its specific function while collectively solving the contradiction between rigidity and flexibility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different portions of the drill bit have different structural properties. The full diameter shaft provides rigidity for torque transmission, the reduced diameter shaft provides flexibility for navigating curves, and the fluted tip provides cutting capability. This local differentiation of properties resolves the contradiction by having the right property in the right location.

Inventive Principle:
Principle #3Local quality

2Force

If the drill bit diameter is increased to improve torque transmission, then drilling capability is improved, but the flexibility and ability to navigate tight spaces in the hip joint is worsened

Engineering Contradiction:
Improvetorque transmissionVSAvoidflexibility to navigate tight spaces
Core Design Contradiction:
ForceVSAdaptability or versatility

Solution Approach 1:

The drill bit uses a segmented diameter structure with a full diameter shaft for torque transmission and a reduced diameter shaft for flexibility. This allows the system to have both high torque capability and flexibility by having different diameters in different locations rather than a uniform diameter.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The drill bit has different diameters at different locations to optimize local functions. The full diameter shaft locally provides high torque transmission, while the reduced diameter shaft locally provides flexibility, resolving the contradiction between force and adaptability.

Inventive Principle:
Principle #3Local quality

3Adaptability or versatility

If the drill bit is made more flexible to improve ability to navigate curved pathways, then adaptability is improved, but torque transmission capability and drilling stability is worsened

Engineering Contradiction:
Improveability to navigate curved pathwaysVSAvoidtorque transmission capability
Core Design Contradiction:
Adaptability or versatilityVSForce

Solution Approach 1:

The drill bit segments its structure into a flexible reduced diameter shaft and a rigid full diameter shaft. The flexible portion enables navigation of curved pathways while the rigid portion ensures adequate torque transmission, resolving the contradiction between flexibility and force transmission.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different portions of the drill bit have different rigidity properties tailored to their functions. The reduced diameter shaft locally provides flexibility for navigating curves, while the full diameter shaft locally provides rigidity for torque transmission, solving the contradiction between adaptability and force capability.

Inventive Principle:
Principle #3Local quality

4Object-affected harmful factors

If minimally-invasive techniques are used for hip joint procedures, then patient trauma and recovery time are reduced, but the difficulty of performing procedures due to limited access and complex geometry is increased

Engineering Contradiction:
Improvepatient traumaVSAvoiddifficulty of performing procedures
Core Design Contradiction:
Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The drill bit incorporates a curved configuration that matches the natural pathways of the hip joint. This curvature allows the instrument to navigate the complex geometry of the hip joint through limited access points, enabling minimally-invasive procedures while maintaining ease of operation.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The reduced diameter shaft acts as a flexible element that can bend and conform to the curved pathways of the hip joint. This flexibility allows the drill bit to navigate tight spaces and complex geometry through small incisions, reducing patient trauma while maintaining operability.

Inventive Principle:
Principle #30Flexible shells and thin films

Data Source

PatentEP2941208B1Flexible drill bit and angled drill guide for use with the same
Publication Date: 2024.07.24 STRYKER PUERTO RICO LLC
  • EP2941208B1 patent drawingFigure 1
  • EP2941208B1 patent drawingFigure 2
  • EP2941208B1 patent drawingFigure 3

AI summary

A flexible drill bit comprising: a proximal shaft portion for connecting to a source of turning; a distal cutting tip portion for boring into a material; and an intermediate shaft portion extending between the proximal shaft portion and the distal cutting tip portion, the intermediate shaft portion being characterized by (i) sufficient longitudinal flexibility so as to permit the flexible drill bit to be passed along a curve, and (ii) sufficient torsional strength to permit the flexible drill bit to bore into the material. Apparatus for drilling a hole in material, the apparatus comprising: an angled drill guide comprising a curved distal section, a less-curved proximal section, and a lumen extending there between, wherein the less-curved proximal section comprises a flat extending there along for reducing the effective diameter of the less-curved proximal section so as to minimize interference between the angled drill guide and the side wall of an access cannula.