Surgical Handpiece Depth Extension for Bone Screw Length Adjustment

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Solution Overview

Problem

Conventional surgical procedures lack an efficient method for determining the end-to-end depth of bone bores during orthopedic procedures, requiring separate depth gauges and tactile feedback, which can be imprecise.

Innovation Solution

A surgical handpiece system with a depth measurement extension and displacement sensor assembly, coupled with a calibration fixture, allows for precise determination of drill depth by measuring the displacement of the depth measurement extension relative to a surgical screw, using a processor to calculate the necessary screw length adjustment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a separate depth gauge is used to measure bore depth, then the measurement can be obtained, but the procedure becomes complex and time-consuming requiring multiple steps and tactile feedback

Engineering Contradiction:

Improvebore depth measurementVSAvoidmeasurement procedure

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The depth gauge functionality is merged with the surgical drill by integrating a depth measurement extension that couples to the drill shaft. The displacement sensor assembly is integrated into the drill housing, combining the drilling function and depth measurement function into a single unified device, eliminating the need for separate depth gauge measurement steps

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The manual tactile feedback method is replaced with an automated displacement sensor assembly that generates electrical signals responsive to the position of the depth measurement extension. The processor automatically calculates bore depth from these signals, replacing the manual tactile measurement process with an automated sensor-based system

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If manual tactile feedback is used to set the depth gauge, then the measurement can be obtained, but the measurement precision is reduced

Engineering Contradiction:

Improvedepth measurement operationVSAvoidbore depth measurement

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The manual tactile feedback system is replaced with a displacement sensor assembly that provides automated, precise measurement of the depth measurement extension position. The sensor generates electrical signals that are processed to determine exact bore depth, eliminating the imprecision of tactile estimation while maintaining ease of operation through automatic calculation

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If the drill depth is not accurately determined, then the surgical procedure can continue, but the screw length selection becomes incorrect risking tissue damage

Engineering Contradiction:

Improvesurgical procedure efficiencyVSAvoidscrew length accuracy

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The displacement sensor assembly provides real-time feedback on the position of the depth measurement extension during drilling. The processor uses this feedback to automatically calculate and determine the accurate bore depth, which then informs the correct screw length selection, ensuring reliability while maintaining surgical efficiency

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system performs preliminary measurement and calculation of the bore depth before screw selection is made. By determining the exact depth in advance through the integrated sensor system, the surgeon can confidently select the appropriate screw length without risk of error, preventing tissue damage before it occurs

Inventive Principle:

Principle #10Preliminary action

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 automated determination of screw length for orthopedic implants, improving precision and reducing the risk of tissue damage by ensuring proper screw fit.

Implementation Method 1

A displacement sensor assembly is coupled to the first housing and configured to generate a signal responsive to displacement of the depth measurement extension

Methodology Applied

Scientific EffectDisplacement sensing: Displacement

Data Source

PatentUS12426897B2Calibration and adjustment determination of a surgical handpiece system

Publication Date: 2025.09.30 STRYKER CORP

AI summary

A surgical handpiece system capable of determining a suitable screw length for bone fixation with a bone plate that compensates an initial screw length value based on orientation of the surgical handpiece system during a drilling process. The surgical handpiece system comprising a surgical handpiece including a depth measurement extension and a sensor. The depth measurement extension may be configured to determine a thickness of bone when a drill bit is attached and used to drill through the bone. The sensor may be configured to generate an orientation signal responsive to orientation of the depth measurement extension. The surgical handpiece system also comprises a processor in communication with the sensor and configured to determine the suitable screw length for bone fixation based the sensor.