Force-Controlled Medical Support Arm for Safe Organ Retraction

Solution Overview

Problem

Existing medical support arm apparatuses for endoscopic and abdominal surgeries face challenges in safely holding organs due to mechanical failures and precision issues, particularly with position control methods that can cause unintended damage to internal organs during movements caused by respiration or heartbeat, and the limitation to using only magnetic instruments which lack precision and safety.

Innovation Solution

A medical support arm apparatus with an arm unit controlled by force control, equipped with a retractor that holds organs during surgery, allowing for controlled force application to prevent excessive force on organs and enhance safety, and the use of torque sensors to detect and manage forces, thereby reducing the risk of damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If position control is used to move the retractor to a specified position, then the retractor can be positioned accurately, but the retractor may continue to apply force to the organ even after positioning, creating a risk of damage during organ movement due to respiration or heartbeat

Engineering Contradiction:

Improvepositioning precisionVSAvoidexcessive force on organ

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the traditional position control mechanical system with a magnetic field-based control system. The retractor is equipped with a magnet, and a magnetic field generator outside the body controls the retractor's position and force through magnetic interaction, eliminating the need for mechanical wires and pulleys. This allows for continuous adjustment of force magnitude and direction while maintaining positioning precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the control parameter from position-only control to magnetic field strength control. By adjusting the magnitude and direction of the magnetic field, the system can independently control both the position and the force applied by the retractor. This enables the retractor to follow organ movement while maintaining appropriate contact force, preventing damage during respiration and heartbeat.

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If magnetic interaction is used to control the retractor from outside the body, then the retractor can be controlled without mechanical elements, but positioning precision is reduced and unintentional organ damage may occur

Engineering Contradiction:

Improveelimination of mechanical elementsVSAvoidpositioning precision

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent replaces the traditional position control mechanical system with a magnetic field-based control system. The retractor is equipped with a magnet, and a magnetic field generator outside the body controls the retractor's position and force through magnetic interaction, eliminating the need for mechanical wires and pulleys. This allows for continuous adjustment of force magnitude and direction while maintaining positioning precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent implements a feedback control system that uses imaging data (such as from an endoscope or other imaging device) to detect the actual position and movement of the organ. This feedback information is used to adjust the magnetic field in real-time, ensuring the retractor maintains precise positioning relative to the moving organ while applying appropriate force.

Inventive Principle:

Principle #23Feedback

3Productivity

If a retractor is inserted into the body cavity to hold an organ, then the work space can be secured, but the retractor may contact and damage the organ during movement or when the organ moves due to respiration or heartbeat

Engineering Contradiction:

Improvework space securingVSAvoidorgan damage risk

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the traditional position control mechanical system with a magnetic field-based control system. The retractor is equipped with a magnet, and a magnetic field generator outside the body controls the retractor's position and force through magnetic interaction, eliminating the need for mechanical wires and pulleys. This allows for continuous adjustment of force magnitude and direction while maintaining positioning precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent transitions from static position control to dynamic force control. The magnetic field-based system can continuously adjust the force applied by the retractor in real-time, allowing the retractor to dynamically follow organ movement during respiration and heartbeat while maintaining appropriate contact force. This dynamic control prevents damage while securing the organ for surgery.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS10856726B2Medical support arm apparatus

Publication Date: 2020.12.08 SONY GROUP CORP

AI summary

The present invention aims to make it capable of holding organs more safely.Provided is a medical support arm apparatus, including: an arm unit (510) whose driving is controlled by force control; and a retractor, provided on a front end of the arm unit (510), that holds an organ of a patient during surgery.