Tendon-Driven Surgical Joint for Low-Friction Microsurgery

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Solution Overview

Problem

Current robotic surgical assemblies face challenges in achieving precise kinematic control and miniaturization for microsurgical procedures due to friction issues and mechanical limitations, leading to difficulties in accessing small surgical sites and requiring extensive training for surgeons.

Innovation Solution

A medical instrument with a jointed device and tendon driving system that uses convex contact surfaces and a pusher assembly to minimize friction and allow for precise, miniaturized movements, enabling easier access to small surgical sites and reducing the complexity of the master-slave interface for intuitive control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If traditional robotic assemblies use multiple independent movements for surgical instrument positioning, then the instrument can access the operating field through surgical ports, but the control of kinematic accuracy becomes difficult and the operating field becomes encumbered

Engineering Contradiction:
Improveaccess to operating fieldVSAvoidcontrol complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent replaces the traditional mechanical master-slave robotic system with a direct-drive system where the surgeon manually positions the surgical instrument without complex mechanical linkages. This substitution eliminates the need for multiple independent movements and complex control mechanisms while maintaining access to the operating field through surgical ports.

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

2Ease of operation

If robotic assemblies use serial kinematic chains with multiple joints, then the surgical instrument tip can be positioned in three-dimensional space, but the joints clutter the operating field and require long training for operators

Engineering Contradiction:
Improveinstrument positioning capabilityVSAvoidjoint articulation complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent extracts and removes the complex serial kinematic chains and multiple joints from the surgical instrument system. By eliminating these mechanical components, the operating field is decluttered and the instrument can be positioned in three-dimensional space without encumbrance, while also reducing the training required for operators.

Inventive Principle:
Principle #2Taking out (Extraction)

3Length of moving object

If the surgical instrument is miniaturized for microsurgery, then access to small surgical sites is improved, but friction and mechanical limitations increase

Engineering Contradiction:
Improveinstrument sizeVSAvoidfriction
Core Design Contradiction:
Length of moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent eliminates mechanical friction by replacing the traditional mechanical drive system with a direct manual manipulation system. The surgeon directly controls the surgical instrument without mechanical linkages, tendons, or actuators that would generate friction, thereby enabling miniaturization for microsurgery without being constrained by friction and mechanical limitations.

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

Data Source

PatentEP3361981B1Surgical tool for robotic surgery and robotic surgical assembly
Publication Date: 2024.10.02 MEDICAL MICROINSTRUMENTS INC
  • EP3361981B1 patent drawingFigure 1A~1B
  • EP3361981B1 patent drawingFigure 1C~2A
  • EP3361981B1 patent drawingFigure 2B~3

AI summary

It is an object of the present invention a medical instrument (60, 160, 260, 360) for surgery comprising at least one frame (57) and at least one jointed device (70, 170, 270), wherein said jointed device (70, 170, 270) comprises at least one first joint member (71), or first link (71), adapted to connect to at least one portion of said frame (57) and at least one second joint member (72), or second link (72); wherein said first joint member (71) is connected by means of a rotational joint (171) to said second joint member (72); and wherein said medical instrument (60, 60, 260, 360) further comprising at least a pair of tendons (90, 190), adapted to move said second joint member (72) with respect to said first joint member (71), pulling it; and wherein each of said first joint member (71) and said second joint member (72) comprises a main structural body comprising in a single piece one or more convex contact surfaces (40, 80, 86, 40, 180), and wherein each of said convex contact surfaces (40, 80, 86, 140, 180) is a ruled surface formed by a plurality of straight line portions all parallel to each other and substantially parallel to a joint movement axis (P-P, Y-Y).