Medical Device Orientation Estimation via Acceleration Data

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Solution Overview

Problem

Existing medical devices struggle to accurately determine their orientation relative to a patient's body without manual calibration or relying on assumptions about the yaw angle, leading to potential inaccuracies in posture monitoring and therapy delivery.

Innovation Solution

A medical device with a 3D accelerometer unit and processor that differentiates between active and rest states, calculates actual orientation and yaw-angle by processing acceleration data, and stores specific acceleration data to determine the device's orientation relative to the patient's body, eliminating the need for manual calibration and assumptions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual calibration is used to determine device orientation, then orientation accuracy is improved, but device complexity and ease of operation deteriorate due to cumbersome procedures and repeated calibration needs

Engineering Contradiction:

Improveorientation accuracyVSAvoidcalibration convenience

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The device automatically determines its orientation relative to the patient's body using acceleration data processed by the processor, eliminating the need for manual calibration procedures. The system self-calibrates by analyzing movement patterns and identifying the device's spatial orientation without requiring patient participation or external programming tools.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The device performs preliminary automatic orientation determination during initial operation to establish the reference frame before clinical use. By pre-determining the device-to-body orientation relationship, the system avoids the need for repeated manual calibration procedures during patient follow-ups.

Inventive Principle:

Principle #10Preliminary action

2Ease of operation

If existing automatic estimation algorithms are used, then ease of operation is improved, but measurement precision deteriorates due to incorrect assumptions about yaw angle

Engineering Contradiction:

Improveautomatic calibration convenienceVSAvoidorientation accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent replaces the mechanical assumption-based approach with a data-driven computational method. Instead of assuming the yaw angle is zero based on implantation location, the system uses acceleration sensors to empirically determine the actual orientation through mathematical processing of movement data, substituting physical assumptions with measured evidence.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system dynamically determines orientation parameters (including yaw angle) based on actual acceleration data rather than using fixed assumed values. The processor calculates the device-to-body transformation matrix by analyzing acceleration patterns, allowing the orientation parameters to adapt to the actual implantation geometry rather than relying on predetermined parameter values.

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If cluster analysis is used for automatic calibration, then measurement precision is improved, but device complexity and use of energy worsen due to computational intensity

Engineering Contradiction:

Improveorientation accuracyVSAvoidcomputational energy consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent extracts only the essential orientation determination functionality from complex cluster analysis methods. By focusing specifically on calculating the device-to-body transformation matrix using acceleration data during rest states, the system achieves accurate orientation determination without the computational overhead of full cluster analysis, removing unnecessary processing complexity while retaining core functionality.

Inventive Principle:

Principle #2Taking out (Extraction)

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

This solution provides accurate and automatic estimation of device orientation, improving posture monitoring and therapy delivery by eliminating the need for manual calibration and assumptions, enhancing clinical applications such as heart failure monitoring and activity recognition.

Implementation Method 1

an accelerator unit configured to determine 3-dimensional proper acceleration data along sensitive axes corresponding to the three orthogonal axes of the medical device

Methodology Applied

Scientific EffectProper acceleration measurement: Accelerometer

Data Source

PatentUS20240216683A1Medical device and method for determining an orientation of same

Publication Date: 2024.07.04 BIOTRONIK SE & CO KG

AI summary

A medical device for implantation within or mounting on a patient's body includes an accelerator unit, a data memory unit and a processor which are electrically interconnected. Three orthogonal axes (XD, YD, ZD) are defined for the medical device and three orthogonal axes (XP, YP, ZP) are defined for the patient's body. The accelerator unit is configured to determine 3-dimensional proper acceleration data along sensitive axes corresponding to the three orthogonal axes of the medical device (XD, YD, ZD). In order to provide an automatic estimation of medical device orientation with regard to a patient's body (thereby overcoming the drawbacks of manual calibration methods) which does not make a priori assumptions about the device's orientation or specific prevalence, the processor is configured to process said acceleration data determined by the accelerator unit.