Static-Bar Reciprocating Saw Cartridge for Low-Trauma Tissue Cutting

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Reciprocating saw blades cause undesirable side effects such as tissue damage due to friction-induced heating and difficulty in visualizing the blade end during surgery, and they wear down resection guides, leading to debris generation and guide failure.

Innovation Solution

A reciprocating saw blade cartridge with a static bar and a rack that minimizes tissue contact to the blade body, allowing only the cutting teeth to move, and includes features to prevent debris accumulation and guide wear.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a reciprocating saw blade is used to cut tissue, then cutting function is achieved, but friction-induced heating damages soft tissue

Engineering Contradiction:
Improvecutting functionVSAvoidfriction-induced heating
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The saw blade is segmented into a reciprocating portion (teeth only) and a static portion (bar). The reciprocating rack with teeth performs the cutting motion while the bar remains stationary, eliminating friction heating of soft tissue by the blade body during reciprocation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The harmful reciprocating motion is extracted from the entire blade and applied only to the cutting teeth portion. The bar is held static while only the rack with teeth reciprocates, separating the cutting function from the harmful frictional contact.

Inventive Principle:
Principle #2Taking out (Extraction)

2Ease of operation

If the blade is positioned to cut tissue, then cutting access is achieved, but the blade end becomes difficult to visualize

Engineering Contradiction:
Improvecutting accessVSAvoidblade end visibility
Core Design Contradiction:
Ease of operationVSDifficulty of detecting and measuring

Solution Approach 1:

The static bar serves as an intermediary that extends the visible portion of the instrument into the surgical field. Since the bar remains stationary, it provides a visible reference that helps surgeons track the position and orientation of the hidden reciprocating teeth portion.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If the reciprocating saw blade moves back and forth rapidly, then cutting speed is improved, but tissue stress causes tearing or damage

Engineering Contradiction:
Improvecutting speedVSAvoidtissue stress
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The rapid reciprocating motion is segmented and applied only to the teeth portion rather than the entire blade. This allows high-speed cutting while the static bar prevents transmission of vibrational stress to surrounding soft tissue.

Inventive Principle:
Principle #1Segmentation

4Manufacturing precision

If the blade is inserted into a resection guide, then planar cut is ensured, but metal wear generates debris that contaminates tissue

Engineering Contradiction:
Improveplanar cut qualityVSAvoidmetal debris
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The reciprocating motion is extracted from the bar and applied only to the rack with teeth. This eliminates metal-to-metal friction between the bar and resection guide, preventing wear debris generation while maintaining precise planar cutting through the guide's slot.

Inventive Principle:
Principle #2Taking out (Extraction)

5Ease of operation

If the reciprocating saw blade is used in confined spaces, then surgical access is achieved, but the distal section of the blade is hidden from view

Engineering Contradiction:
Improvesurgical accessVSAvoidblade position monitoring
Core Design Contradiction:
Ease of operationVSDifficulty of detecting and measuring

Solution Approach 1:

The static bar acts as a visible intermediary that extends into the surgical field. Surgeons can observe the bar's position and orientation to indirectly monitor the location of the hidden reciprocating teeth, enabling safe operation in confined spaces like the nasal cavity.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Reduces tissue damage and debris generation, enhances visibility of the blade end, and maintains the integrity of resection guides, ensuring precise cuts without additional saw requirements.

Implementation Method 1

the rack having a head that extends from the base and that is located outside a perimeter of the bar, the head having teeth for cutting tissue against which the teeth are pressed

Methodology Applied
Scientific EffectAbrasion: Abrasion

Implementation Method 2

This rapid movement of the blade can foster appreciable friction-induced heating of the soft tissue against which the blade body is pressed

Methodology Applied
Scientific EffectFriction-induced heating: Friction

Data Source

PatentEP3389512B1Reciprocating saw blade cartridge that includes a static bar to which a reciprocating rack is attached
Publication Date: 2025.09.24 STRYKER EUROPEAN OPERATIONS HOLDINGS LLC
  • EP3389512B1 patent drawingFigure 1
  • EP3389512B1 patent drawingFigure 2~3
  • EP3389512B1 patent drawingFigure 4~5

AI summary

A surgical blade cartridge (80) that includes a blade bar (82) in which a rack (112) is moveably mounted. Teeth (126) extend outwardly from the portion of the rack disposed outside of the bar. The blade bar and rack are formed with a complementary static member (106) and a slot (120) such that the static member seats in the slot so as to retain the rack in the bar and allow the rack to move reciprocate linearly