Surgical Cutting Instrument with Nested Arms and Pivot Force Mechanism

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Solution Overview

Problem

Current surgical instruments for cutting elongated elements, such as bone anchors and rods, lack a compact design and sufficient mechanical advantage to effectively cut elements within a surgical setting, particularly in limited spaces, and are not suitable for pre-insertion cutting.

Innovation Solution

A surgical instrument with pivotally connected arms and a force mechanism that allows for a compact size, enabling insertion into a patient to cut elongated elements, featuring blades positioned at the distal ends and a force mechanism between the arms to pivot between open and closed orientations, allowing for precise cutting with mechanical advantage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the surgical instrument is designed with a compact size for insertion into the patient, then the instrument can be used in limited surgical spaces, but the instrument lacks sufficient mechanical advantage to effectively cut elongated elements

Engineering Contradiction:
Improveinstrument sizeVSAvoidcutting force
Core Design Contradiction:
Volume of moving objectVSForce

Solution Approach 1:

The instrument is divided into two arms that can pivot relative to each other, with cutting elements positioned at the distal ends. This segmentation allows the arms to apply force from opposite directions, concentrating cutting force at the distal ends while keeping the proximal sections compact for insertion.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The force mechanism is positioned between the arms in a configuration that utilizes the space between them, creating a compact arrangement that provides mechanical advantage without increasing the overall insertion profile. The pivot connection allows rotational movement that amplifies cutting force.

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

2Manufacturing precision

If the cutting elements are positioned at the distal ends of the arms, then the instrument can cut elongated elements at the proper location, but the overall instrument size increases

Engineering Contradiction:
Improvecutting position precisionVSAvoidinstrument size
Core Design Contradiction:
Manufacturing precisionVSVolume of moving object

Solution Approach 1:

The instrument is segmented into two arms with cutting elements at the distal ends, allowing precise positioning at the cutting site while keeping the proximal sections compact for insertion.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The arms are configured to overlap in a nested arrangement when viewed from the distal end, with one arm positioned within the channel formed by the other arm's walls. This nesting minimizes the overall instrument width while maintaining distal cutting capability.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Volume of moving object

If the arms are positioned in an overlapping arrangement with one arm in the channel of the other, then the instrument achieves a compact profile, but the structure becomes more complex

Engineering Contradiction:
Improveinstrument profileVSAvoidarm structure complexity
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

One arm is positioned within the channel formed by the walls of the other arm, creating a nested configuration that minimizes the overall instrument profile while maintaining structural integrity through the pivot connection.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The two arms are merged through a pivot connection that allows rotational movement while maintaining the overlapping arrangement. This combining of elements creates a compact structure that achieves both size reduction and functional capability.

Inventive Principle:
Principle #5Merging (Combining)

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 instrument provides a compact, effective means to cut elongated elements within a surgical setting, ensuring precise cutting and efficient removal of excess sections, while maintaining a reduced overall size for use in limited spaces.

Implementation Method 1

a pivot member positioned in the distal sections of the first and second arms... the pivot member including a second aperture that aligns with the first aperture

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

a force mechanism attached to the proximal sections of the first and second arms to pivot the first and second arms about the pivot member between an open orientation with the cutting elements spaced apart and a closed orientation with the cutting elements positioned in proximity to each other

Methodology Applied
Scientific EffectMechanical Advantage: Mechanical Advantage

Data Source

PatentEP2638875B1Surgical instruments for cutting elongated elements
Publication Date: 2015.07.29 WARSAW ORTHOPEDIC INC
  • EP2638875B1 patent drawingFigure 1
  • EP2638875B1 patent drawingFigure 2
  • EP2638875B1 patent drawingFigure 3

AI summary

A surgical instrument for cutting an elongated element. The surgical instrument may have a compact size for use in-situ during a surgical procedure. The surgical instrument is also configured to provide the necessary mechanical advantage to cut the elongated element. The surgical instrument may include first and second arms that are pivotally connected together at a pivot. The arms include blades positioned at or towards distal ends of the arms that act together to cut the elongated element. A force mechanism is positioned between the arms to pivot the arms between an open orientation and a closed cutting orientation. The force mechanism may be positioned directly between the arms to reduce the overall size of the instrument.