Patient-Specific Surgical Guide for Prosthetic Implant Alignment

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Solution Overview

Problem

Current methods for accurately positioning prosthetic implants, such as acetabular and glenoid components, during hip and shoulder surgeries face challenges due to reliance on visual judgment, distorted anatomical landmarks, and the complexity of compound angles, leading to potential misalignment and increased risk of dislocation or loosening of the prosthetic joint.

Innovation Solution

A surgical guide system that utilizes preoperative imaging to create a patient-specific model, allowing for the precise planning of fastener placement and trajectory, with a custom-manufactured guide that includes guiding apertures and orienting features to ensure accurate alignment and orientation of the prosthetic implant relative to the patient's tissue, facilitating correct positioning and secure attachment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If visual judgment and mechanical positioners are used to position the acetabular cup, then the surgical procedure can be performed without expensive navigation systems, but the positioning accuracy and reliability are compromised due to distorted anatomical landmarks and compound angle complexity

Engineering Contradiction:
Improvepositioning accuracyVSAvoidsurgical procedure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The surgical guide is designed and manufactured before surgery based on preoperative imaging data (CT or MRI scans). The guide incorporates pre-calculated positioning information, including the exact orientation angles (45-50° abduction, 15-20° anteversion) and depth markers, eliminating the need for complex intraoperative visual judgments and mechanical measurements

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patient-specific surgical guide acts as an intermediary device between the preoperative imaging data and the actual implant placement. It translates the complex 3D positioning requirements into simple mechanical guidance through its contoured mating surface and guiding apertures, making the surgical procedure straightforward while maintaining high precision

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If expensive surgical navigation systems are used to achieve precise implant placement, then positioning accuracy improves, but the cost and complexity of the surgical system increase significantly

Engineering Contradiction:
Improveimplant placement accuracyVSAvoidsystem cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

Instead of using expensive real-time navigation systems, the invention creates a physical copy or replica of the patient's anatomy through the custom-manufactured surgical guide. This guide is produced from preoperative imaging data using additive manufacturing or CNC machining, providing all necessary positioning information in a tangible, low-cost format that can be used throughout the surgical procedure

Inventive Principle:
Principle #26Copying

Solution Approach 2:

All complex calculations and positioning determinations are performed before surgery during the guide manufacturing process. The guide incorporates pre-determined orientation angles, depth markers, and alignment features, transferring the computational complexity from the expensive intraoperative navigation system to the inexpensive preoperative planning and guide fabrication stage

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If standard mechanical positioners are used that rely on pelvis positioning, then the equipment is simple and inexpensive, but the positioning reliability deteriorates when the patient is obese or the pelvis cannot be positioned correctly

Engineering Contradiction:
Improvepositioning equipment simplicityVSAvoidpositioning reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The surgical guide is designed with a contoured lower surface that mates specifically with the unique anatomical features of each patient's acetabulum and ilium. This localized customization ensures reliable positioning based on the patient's actual bone geometry rather than relying on general pelvis positioning that may be compromised by obesity or anatomical variations

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The guide is manufactured before surgery with pre-programmed positioning information tailored to each patient's anatomy. The guide's geometry encodes the correct orientation and placement information, ensuring reliable reproduction of the preoperative plan regardless of the patient's body habitus or intraoperative positioning challenges

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3449848B1System for assisting with attachment of a stock implant to a patient tissue
Publication Date: 2025.01.01 THE CLEVELAND CLINIC FOUND
  • EP3449848B1 patent drawingFigure 1
  • EP3449848B1 patent drawingFigure 2~3
  • EP3449848B1 patent drawingFigure 4~5

AI summary

A guide for assisting with attachment of a stock prosthetic implant to a patient tissue includes a lower guide surface configured to contact an upper implant surface of the stock prosthetic implant when a lower implant surface of the stock prosthetic implant contacts the patient tissue. An upper guide surface is accessible to a user when the lower guide surface is in contact with the upper implant surface. At least one guiding aperture extends through the guide body between the upper and lower guide surfaces at a predetermined aperture location with respect to the guide body and defines a predetermined target trajectory through the guide body. At least one of the target trajectory and the aperture location of each guiding aperture is preselected responsive to preoperative imaging of the patient tissue. A method of assisting with attachment of a stock prosthetic implant to a patient tissue is also provided.