Active Orthopedic Retract Force Control

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Solution Overview

Problem

Conventional retractors lack the ability to provide a constant retracting force in real-time to fractured bone fragments, limiting their effectiveness in aligning and stabilizing bone fragments during fracture reposition surgery.

Innovation Solution

An active retractor system equipped with a retracting force measuring sensor, displacement measuring sensor, controller, and actuator that measures and adjusts the retracting force and position in real-time, allowing for precise control and maintenance of the required retracting force and location, guided by a user interface and display devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a conventional retractor is used to retract bone fragments by a fixed mechanical configuration, then the retraction can be provided at a fixed location, but the retracting force cannot compensate for stress changes during fracture reposition

Engineering Contradiction:
Improveretracting forceVSAvoidadaptability to stress changes
Core Design Contradiction:
ForceVSAdaptability or versatility

Solution Approach 1:

The retractor is transformed from a static mechanical configuration to a dynamic active retractor that can adjust its retracting force in real-time. The actuator enables the retractor to dynamically respond to stress changes during fracture reposition, providing adaptive retracting force rather than a fixed mechanical configuration.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The sensor detects the actual stress state of the fractured area during fracture reposition and provides feedback to the controller. The controller uses this feedback to adjust the actuator's output, ensuring the retracting force compensates for stress changes and maintains the necessary force for effective retraction.

Inventive Principle:
Principle #23Feedback

2Force

If a conventional retractor provides fixed location retraction, then the structure is simple, but it cannot provide the necessary retracting force for surgical intentions during dynamic fracture reposition

Engineering Contradiction:
Improveretracting forceVSAvoiddevice complexity
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The conventional mechanical retraction system is replaced with an active retractor that uses an actuator (electromechanical or hydraulic system) to provide controlled retracting force. This substitution allows for precise force control and real-time adjustment, overcoming the limitations of simple mechanical configurations.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The actuator serves as an intermediary between the control system and the bone fragment, enabling precise transmission of retracting force. The sensor-controller-actuator loop acts as an intermediary system that mediates between the surgical intention and the actual retraction force applied to the bone fragment.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If manual manipulation is used for fracture reposition, then the surgical operator has control, but the operator bears the full burden of providing necessary retracting force

Engineering Contradiction:
Improveease of operationVSAvoidretracting force
Core Design Contradiction:
Ease of operationVSForce

Solution Approach 1:

The active retractor performs self-adjustment through the sensor-controller-actuator feedback loop, automatically compensating for stress changes and maintaining the necessary retracting force. This self-service capability reduces the burden on the surgical operator, who no longer needs to manually provide and adjust the retracting force.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The sensor continuously monitors the stress state and provides feedback to the controller, which automatically adjusts the actuator output. This closed-loop feedback system handles the force adjustment automatically, freeing the surgical operator from the burden of manually managing retracting force while maintaining ease of operation.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3701891B1Active traction device for orthopedic surgery
Publication Date: 2023.08.02 KYUNGPOOK NAT UNIV IND ACADEMIC COOP FOUND
  • EP3701891B1 patent drawingFigure 1~2
  • EP3701891B1 patent drawingFigure 3~4
  • EP3701891B1 patent drawingFigure 5~6

AI summary

This disclosure relates to an active retractor implemented to detect a stress state of a fractured area during fracture reposition and compensate for a required retracting force, and a control method thereof. The active retractor includes: a retracting shaft configured to fasten fractured bone fragments of a patient and retract the fractured bone fragments in a front and rear direction; a measuring device connected and installed to the retracting shaft to measure a retracting location or a retracting force of the retracting shaft; an actuator connected and installed to the retracting shaft to drive the retracting shaft in the front and rear direction; a driver configured to supply a power required for driving the actuator to the actuator according to a driving control signal; and a controller configured to generate a driving control signal, which is required for the driver to supply a power, by comparing a retracting request signal input from a user with a measured value transmitted from the measuring device and transmit the driving control signal to the driver.