Surgical Instrument Drive Unit Sterile Barrier Interface

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Solution Overview

Problem

Current surgical instrument systems face challenges in providing adequate sterility and effective force feedback during minimally invasive procedures, particularly due to the difficulty in connecting instruments to manipulators while maintaining sterility and accurately transmitting forces through the instrument shaft.

Innovation Solution

A surgical instrument arrangement with a modular motorized drive unit and a mechanical interface that allows for detachable connection between the drive unit and instrument shaft, featuring a one-sided binding mechanism and a sterile barrier to maintain sterility, along with a measuring arrangement to detect loads and provide haptic feedback.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a mechanical interface with two-sided binding is used to connect the drive unit and instrument shaft, then force transmission is improved, but sterility maintenance deteriorates

Engineering Contradiction:
Improveforce transmissionVSAvoidsterility maintenance
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The mechanical interface is segmented into two separate binding mechanisms: a one-sided binding component (peg in recess) that maintains sterility by allowing relative movement, and a separate force transmission mechanism (spring-loaded contact surfaces) that provides two-sided force binding. This segmentation allows each component to fulfill its specific function without compromising the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A sterile barrier (membrane) is introduced as an intermediary element between the drive unit and instrument shaft. The membrane allows force transmission through it while maintaining sterility, acting as a mediator that reconciles the conflicting requirements of force binding and sterility maintenance.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a sterile barrier is introduced between the drive unit and instrument shaft, then sterility maintenance is improved, but force transmission deteriorates

Engineering Contradiction:
Improvesterility maintenanceVSAvoidforce transmission
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

A flexible membrane (sterile barrier) is used instead of a rigid barrier. The membrane's flexibility allows it to deform under force, enabling force transmission from the drive unit to the instrument shaft while maintaining the sterile seal. The membrane acts as a force-transmitting diaphragm that reconciles sterility with mechanical coupling.

Inventive Principle:
Principle #30Flexible shells and thin films

3Reliability

If a one-sided binding mechanism is used for the mechanical interface, then sterility maintenance is improved, but force transmission deteriorates

Engineering Contradiction:
Improvesterility maintenanceVSAvoidforce transmission
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The patent combines multiple binding mechanisms into a single integrated mechanical interface: the one-sided peg-in-recess binding for sterility, spring-loaded contact surfaces for two-sided force transmission, and a membrane for sterile force coupling. This merging of multiple functions into one interface resolves the contradiction between one-sided binding and force transmission.

Inventive Principle:
Principle #5Merging (Combining)

4Ease of operation

If the instrument shaft is detachably connected to the drive unit, then ease of operation is improved, but connection reliability deteriorates

Engineering Contradiction:
Improvedetachable connectionVSAvoidconnection reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The mechanical interface is designed with preliminary alignment features (guided insertion, form-fit connections) that ensure proper positioning before final engagement. The peg-in-recess mechanism provides preliminary mechanical guidance, and the spring-loaded contacts engage automatically upon insertion, ensuring reliable connection without complex manual alignment procedures.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2896382B1Surgical instrumentation and drivetrain assembly for a surgical instrument, in particular a robot-controlled instrument and surgical instrument
Publication Date: 2019.11.20 KUKA DEUT GMBH
  • EP2896382B1 patent drawingFigure 1~2
  • EP2896382B1 patent drawingFigure 3~4
  • EP2896382B1 patent drawingFigure 5~7(e)

AI summary

A surgical instrument arrangement according to the invention comprises, in one aspect, a modular motor drive unit (1) comprising an output arrangement with at least one output element (10A, 10B; 100; 1000); and an instrument shaft (2) which is detachably connectable to the drive unit and a drive arrangement with at least one input element (20A, 20B; 200; 2000), wherein the output arrangement and the drive arrangement can be coupled to each other by means of a mechanical interface, wherein the surgical instrument arrangement comprises a sterile barrier (3) which is provided to enclose the drive unit and is arranged between the drive unit and the instrument shaft, and which, in the area of ​​the mechanical interface, has a, in particular pre-tensioned, play in an adjustment direction of the output and drive arrangement, a non-contact translationally displaceable seal (3).5), a compensating means for tolerance compensation and/or an element extension which is detachably connectable to a drive element base (11; 21) which penetrates the sterile barrier in a destructive manner.