Adaptive Surgical Tool Planning for Precise Bone Cuts

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Solution Overview

Problem

Existing robotically-assisted surgical systems for total knee arthroplasty face challenges in minimizing relative cutting errors during the preparation of planar cuts, leading to potential misalignment of prosthetic components and increased surgical complications due to technical limitations, surgeon dexterity, and perception errors.

Innovation Solution

A surgical system incorporating a robotic device with haptic or autonomous capabilities, a tracking system, and a computing system that updates the surgical plan intraoperatively to minimize cutting errors by tracking the tool center point and adjusting the surgical plan based on actual cut deviations, using fiducial markers and haptic feedback to guide the surgical tool.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a pre-established surgical plan is used for multiple bone cuts, then surgical efficiency is improved, but cumulative cutting errors increase leading to misalignment

Engineering Contradiction:
Improvesurgical efficiencyVSAvoidcutting precision
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The system implements real-time feedback by tracking the actual position and orientation of each bone cut, comparing it to the planned cut, and using this information to update subsequent cuts. The robotic system continuously monitors cutting deviations and adjusts the surgical plan dynamically, ensuring that cumulative errors do not accumulate across multiple cuts.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The surgical plan transitions from a static pre-operative plan to a dynamic intraoperative plan. The system allows real-time modification of cut parameters based on actual cutting results, enabling the surgical plan to adapt and evolve during the procedure rather than remaining fixed as originally planned.

Inventive Principle:
Principle #15Dynamics

2Manufacturing precision

If robotic assistance is used to improve cutting precision, then manufacturing precision is improved, but device complexity increases

Engineering Contradiction:
Improvecutting precisionVSAvoidsystem complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The robotic system performs multiple functions including positioning the surgical tool, tracking cut locations, calculating deviations, and updating surgical plans. This multi-functional approach consolidates what would otherwise require separate devices into a single integrated robotic platform, managing complexity while maintaining precision.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The robotic system acts as an intermediary between the surgeon's intent and the actual bone cutting. It translates the surgical plan into precise robotic movements and provides force feedback to guide the surgeon, mediating the interaction to achieve higher precision without requiring the surgeon to directly control every movement.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If haptic feedback is provided to guide the surgical tool, then ease of operation is improved, but device complexity increases

Engineering Contradiction:
Improvesurgeon controlVSAvoidrobotic system complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The haptic feedback system provides self-guidance to the surgeon by delivering force cues that naturally guide the surgical tool along the planned cut path. The system serves itself by using the surgeon's own manual control inputs and providing corrective haptic forces, eliminating the need for complex external control mechanisms.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3915505B1Systems for adaptive planning and control of a surgical tool
Publication Date: 2025.09.10 MAKO SURGICAL CORP
  • EP3915505B1 patent drawingFigure 1A~1B
  • EP3915505B1 patent drawingFigure 2
  • EP3915505B1 patent drawingFigure 3

AI summary

A surgical system includes a robotic device having a surgical tool, a tracking system, and a processing system communicably coupled to the robotic device. The processing system is configured to store a surgical plan comprising a first planned cut and one or more additional planned cuts, each additional cut defined by a relative angle and distance from the first planned cut, receive tracking data from the tracking system while the surgical tool makes a cut substantially corresponding to the first planned cut, and determine a recorded first cut plane based on the first tracking data. The processing system is further configured to determine an error between the recorded first cut plane and the planned first cut, the error comprising a deviation from the planned first cut, and update the surgical plan by modifying the one or more additional planned cuts based on the deviation.