Ultrasound Surgical Tool Localization for Radiation-Free Navigation
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Solution Overview
Problem
Existing medical navigation systems for precise tool placement, such as pedicle screw insertion, are costly, expose patients to radiation, and have high malposition rates, making them unsuitable for pediatric and pregnant patients.
Innovation Solution
A surgical navigation system using ultrasound transducers integrated into tools to measure distances and determine the tool's pose relative to the patient's anatomy, providing real-time feedback through a user interface for accurate tool positioning without radiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If intraoperative cone-beam CT and optical tool tracking are used for navigation, then manufacturing precision and measurement precision are improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces complex mechanical and optical tracking systems with ultrasound-based ranging sensors that measure distance to bone surface. This substitution reduces device complexity while maintaining positioning accuracy through acoustic time-of-flight measurements and triangulation algorithms.
Solution Approach 2:
The patent extracts the essential function of navigation (position determination) from the complex cone-beam CT and optical tracking system, implementing it through simpler ultrasound ranging sensors and computational geometry that only require distance measurements to bone landmarks.
2Measurement precision
If intraoperative fluoroscopy is used for imaging guidance, then measurement precision is improved, but object-affected harmful factors increase due to radiation exposure
Solution Approach 1:
The patent substitutes ionizing radiation-based fluoroscopy with ultrasound-based ranging that uses acoustic waves. This provides equivalent positioning guidance information without the harmful radiation effects on patients and surgical staff.
Solution Approach 2:
The patent converts the potentially harmful ultrasound energy into a beneficial navigation tool, where the acoustic waves provide precise distance measurements for tool positioning without the ionizing radiation damage associated with fluoroscopy and cone-beam CT.
3Device complexity
If traditional freehand technique is used for screw placement, then device complexity is reduced, but manufacturing precision and measurement precision worsen with high malposition rates
Solution Approach 1:
The patent enables the surgical tool to self-determine its own position and orientation by using integrated ultrasound ranging sensors to measure distances to bone landmarks. This self-localization capability provides automated positioning guidance while maintaining operational simplicity for the surgeon.
Solution Approach 2:
The patent implements real-time feedback through continuous ultrasound ranging measurements that provide positional information about the tool relative to the bone. This feedback loop allows dynamic adjustment of tool placement while maintaining procedural simplicity.
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
Enables accurate and cost-effective tool localization with sub-millimeter precision, reducing malposition rates and eliminating radiation exposure, suitable for diverse patient populations.
Implementation Method 1
A plurality of ultrasound transducers are integrated into a surgical tool. The transducers are used to measure distances between points having known locations relative to the surgical tool and points on a surface of the bone.
Implementation Method 2
The transducers are operative to output one or more signals that encode plural measured distances. A data processing system processes the one or more signals to obtain the plural measured distances.
Data Source
AI summary
Apparatus for monitoring a pose of a tool relative to an object includes plural range sensors arranged on a support. The range sensors may be provided by plural ultrasound transducers. The support is integrated with or coupled to: the tool. The tool may comprise a guide configured to constrain another tool to be moved along an axis defined by the guide. The transducers output signals that encode plural measured distances between points having known locations relative to the support and points on a surface of the object. A data processing system is configured to: process the signals to obtain the plural measured distances; and process the measured distances to generate an estimated pose of the support relative to the object. A user feedback interface is operative to communicate to a user information about a current pose of the tool relative to the object. The apparatus has example application in surgery including drilling holes for pedicle screws.