Surgical Drill Bit Transition Detection Using Acceleration Sensors
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Solution Overview
Problem
Current mechanical depth gauges used in orthopedic and trauma surgery for determining screw lengths are inaccurate, unreliable, and difficult to handle, leading to prolonged surgery times, soft tissue irritation, osteosynthesis failure, and increased hardware costs due to incorrect screw insertion.
Innovation Solution
A surgical instrument that uses a numerical procedure based on displacement characteristics to determine the transition of a drill bit from one medium to another, employing multiple reference graphs to improve the detection of the drill bit exiting the bone cortex, allowing for accurate estimation of bone screw lengths and differentiation between unicortical and bicortical screws.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If mechanical depth gauges are used to determine screw lengths, then the surgical procedure can be performed, but the measurement accuracy and reliability are poor
Solution Approach 1:
The patent replaces mechanical depth gauges with an electronic measurement system that uses an acceleration sensor to detect drilling characteristics. The sensor measures acceleration values during drilling, and a processing unit analyzes these values to determine when the drill bit transitions from cortical to cancellous bone, thereby eliminating the inaccuracies of mechanical gauges.
Solution Approach 2:
The patent introduces an acceleration sensor as an intermediary measurement device that indirectly measures bone density transitions through drilling characteristics. Instead of directly measuring screw length or bone density, the sensor detects acceleration changes during drilling that correlate with tissue transitions, providing reliable indirect measurement.
2Productivity
If mechanical depth gauges are used, then screw length can be estimated, but the surgery time is prolonged
Solution Approach 1:
The patent implements real-time feedback through the acceleration sensor that continuously monitors drilling characteristics and provides immediate detection of bone transitions. This eliminates the need for repeated manual measurements and allows the surgeon to make accurate decisions about screw length based on real-time data, significantly reducing surgery time.
3Measurement precision
If simple threshold values are used to detect tissue transition, then the detection process is simple, but the accuracy of transition detection is poor
Solution Approach 1:
The patent transitions from static threshold values to dynamic analysis of acceleration characteristics. Instead of comparing a single acceleration value against a fixed threshold, the system analyzes the temporal pattern and characteristics of acceleration values during drilling, adapting to varying drilling conditions and bone properties to accurately detect transitions.
Data Source
AI summary
A surgical instrument (25), in particular a surgical cutting or drilling instrument, the surgical instrument (25) comprising: a drive unit; a cutting tool or drill bit (5) engageable with the drive unit; a measuring device (1) which is configured to measure the distance [x(t)] covered by the cutting tool or drill bit (5) along a cutting or drilling path with respect to time and relative to a reference position; a processing un and a digital data storage, wherein in the digital data storage reference data are stored which include at least N one data set specifying a reference graph GRef within a time window (11) in the range of a transition and defining a reference point of a transition (21′), wherein the time window (11) includes a first time period before the reference point of a transition (21′) and a second time period after the reference point of a transition (21′) and wherein the processing unit (14) suitably programmed to compare the recorded graph G with the at least one reference graph GRef and to find 1 lion of a transition (21) in the recorded graph G.