Bone Screw Tip Cutting Features for Reduced Insertion Force

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Solution Overview

Problem

Existing bone screws require significant axial force and torque for insertion, which can cause stress and movement in the body, especially when inserting into damaged or intricate bone areas.

Innovation Solution

The bone screw design incorporates cutting features at the tip and along the threads, including sharp corners and edges created by grooves, notches, and slots, to facilitate easier insertion by cutting into the bone tissue.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If traditional bone screw insertion methods are used, then the bone screw can be securely fixed in the bone, but significant axial force and torque are required which causes stress and movement in the body

Engineering Contradiction:

Improvefixation strengthVSAvoidstress and movement in the body

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The bone screw tip includes pre-formed cutting features (grooves, notches, slots) that are created during manufacturing before insertion. These features perform the preliminary action of cutting and separating bone tissue ahead of the main screw body, allowing the screw to be inserted with significantly reduced axial force and torque, thereby minimizing stress and movement in the body while maintaining secure fixation

Inventive Principle:

Principle #10Preliminary action

2Ease of operation

If cutting features are added to the bone screw tip, then insertion force is reduced, but the device complexity increases

Engineering Contradiction:

Improveinsertion easeVSAvoidscrew structure complexity

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The cutting features at the bone screw tip are segmented into distinct geometric elements including grooves, notches, and slots that are formed as integral parts of the tip structure. This segmentation allows each feature to perform a specific cutting function while being manufactured as a unified structure, reducing operational complexity despite the enhanced cutting capability

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The cutting features are concentrated locally at the tip of the bone screw where they are most needed for initial bone penetration. The main body of the screw remains a simple threaded structure, so the overall device complexity is minimized by applying complex geometry only where necessary for insertion, while maintaining simplicity in the majority of the screw structure

Inventive Principle:

Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The cutting features allow for the insertion of bone screws with lower axial force and torque, reducing stress and movement in the body, and improving navigation accuracy and reducing imaging requirements.

Implementation Method 1

The sharp edges and corners are designed to catch and cut bone tissue to help facilitate the insertion of the bone screw

Methodology Applied

Scientific EffectMechanical cutting: Fracture Mechanics

Data Source

PatentUS20250107833A1Pedicle Screw Tip Insertion Feature

Publication Date: 2025.04.03 VB SPINE LLC

AI summary

A bone screw having cutting features to facilitate the insertion thereof. The bone screw including a shaft portion having a terminal end and a first thread terminating at the terminal end. The first thread including a first crest and a first cut that extends along a helix from the terminal end such that the first crest is divided to create a cutting edge along the first cut.