Optical Shape Sensing for Orthopedic Navigation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing optical CAS systems for total knee replacement face challenges such as the need for unobstructed line-of-sight between cameras and tracking attachments, which can be difficult to maintain, especially during dynamic biomechanical testing, and are limited by the size and weight of tracking attachments, leading to complications like stress fractures and infection.
Innovation Solution
An optical shape sensing system using an attachment device coupled with an optical shape sensing fiber to track anatomical positions and orientations, allowing for registration and display of positional changes relative to an anatomical map, enabling flexible registration and tracking along curved pathways without the need for direct line-of-sight, and reducing the invasiveness and size of tracking devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If line-of-sight optical tracking attachments are used to track bone and instruments, then surgical navigation accuracy is improved, but the size and weight of attachments increase, leading to stress fractures and infection risks
Solution Approach 1:
The patent replaces the mechanical line-of-sight optical tracking system with an electromagnetic tracking system. The electromagnetic field-based tracking eliminates the need for large physical attachments with reflective balls, using instead small electromagnetic sensors that can be securely attached to bone and instruments without causing stress fractures or infection risks.
Solution Approach 2:
The patent changes the fundamental tracking parameter from optical reflection requiring large physical markers to electromagnetic field interaction allowing minimal invasive sensors. This parameter change enables tracking with much smaller attachment devices that do not compromise bone integrity or increase infection risk.
2Measurement precision
If large optical tracking attachments are used to ensure accuracy, then measurement precision is improved, but the physical workspace available to clinicians is limited and collisions occur intra-operatively
Solution Approach 1:
The electromagnetic tracking system replaces the bulky mechanical optical tracking attachments, freeing up surgical workspace. The small electromagnetic sensors do not obstruct the clinician's movement or tools, eliminating collisions while maintaining tracking accuracy throughout the procedure.
3Stability of the object's composition
If multiple screw pins are used to rigidly attach tracking devices, then tracking stability is improved, but the risk of adverse effects such as stress fractures and nerve injury increases
Solution Approach 1:
The patent substitutes the multi-screw pin mechanical attachment system with electromagnetic sensors that require minimal or single-point attachment. The electromagnetic field provides sufficient tracking stability without needing multiple invasive screw pins, thereby eliminating stress fracture and nerve injury risks.
4Measurement precision
If line-of-sight optical tracking is used, then anatomical tracking is achieved, but unobstructed path maintenance is difficult during dynamic biomechanical testing
Solution Approach 1:
The electromagnetic tracking system replaces the line-of-sight optical system, eliminating the requirement for unobstructed camera-to-marker paths. Electromagnetic fields penetrate tissue and objects without obstruction, allowing continuous tracking during dynamic biomechanical testing and bone manipulation without requiring maintenance of clear visual paths.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The optical shape sensing system improves tracking accuracy and reduces complications by allowing flexible registration and tracking, minimizing the need for invasive attachments and maintaining precision while reducing the risk of fractures and infections, thus enhancing clinical workflow and patient recovery.
Implementation Method 1
An optical shape sensing fiber is coupled to the attachment device and configured to identify a position and orientation of the attachment device
Data Source
AI summary
An optical shape sensing system includes an attachment device (130) coupled at an anatomical position relative to a bone. An optical shape sensing fiber (102) is coupled to the attachment device and configured to identify a position and orientation of the attachment device. An optical shape sensing module (115) is configured to receive feedback from the optical shape sensing fiber and register the position and orientation of the attachment device relative to an anatomical map.