Ultrasonic Bone Depth Gauge for Screw Trajectory Alignment
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Solution Overview
Problem
Current methods for determining bone screw trajectories are inaccurate due to variations in bone density and require post-drilling measurement, leading to inefficiencies and increased fluoroscopy use during bone screw insertions.
Innovation Solution
A depth gauge equipped with a transmitter, receiver, and module that estimates fastener-hole depth or length by transmitting and receiving waves through the bone, allowing for pre-drilling determination of screw trajectories, thereby reducing the need for fluoroscopy and improving accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If tactile feedback is used while drilling into the bone to determine desired depth, then the surgeon can estimate depth during drilling, but the measurement is inaccurate due to variations in bone density
Solution Approach 1:
The patent replaces the mechanical tactile feedback system with an ultrasonic wave-based measurement system. The depth gauge uses ultrasonic waves to measure bone depth non-invasively, eliminating the need for manual tactile assessment during drilling. This substitution provides objective, quantifiable measurements that are not affected by variations in bone density or surgeon experience.
Solution Approach 2:
The depth gauge enables preliminary measurement of bone depth before drilling begins. By measuring the distance to the far cortical bone layer in advance, the system allows surgeons to plan the appropriate drill depth and screw length beforehand, rather than relying on real-time tactile feedback during the drilling process.
2Measurement precision
If a depth gauge is used after drilling into the bone to determine drill depth, then a measurement can be obtained, but the measurement is inaccurate since the drill depth is not determined until after the hole has been drilled
Solution Approach 1:
The depth gauge performs measurements before drilling occurs, allowing surgeons to determine the exact depth required for each hole beforehand. This preliminary measurement eliminates the need for post-drilling verification and allows for precise drill depth control during the procedure, saving time by avoiding corrective actions or additional measurements.
Solution Approach 2:
The system provides feedback to the surgeon about the required drill depth and screw length before the drilling process begins. This advance feedback allows for proper planning and preparation, ensuring that the correct screw length is selected and that drilling parameters are set appropriately, thereby avoiding time loss from adjustments or rework.
3Measurement precision
If fluoroscopy is used extensively for bone screw insertions to ensure accurate trajectories, then measurement accuracy improves, but the time and costs required for bone screw insertions increase
Solution Approach 1:
The patent substitutes fluoroscopy-based imaging with a non-invasive ultrasonic depth measurement system. The depth gauge uses ultrasonic waves to measure bone depth and estimate screw trajectories without requiring ionizing radiation. This replacement eliminates the need for repeated fluoroscopy images while providing accurate depth information, thereby reducing both time and cost.
Solution Approach 2:
The depth gauge provides a low-cost, portable alternative to expensive fluoroscopy equipment. By using an inexpensive ultrasonic measurement device, the system achieves accurate depth measurement without the high operational costs and time requirements associated with fluoroscopy suites, making the procedure more efficient and accessible.
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 precise estimation of screw trajectories before drilling, minimizing fluoroscopy use and reducing insertion time and costs by providing accurate pre-drilling measurements.
Implementation Method 1
The receiver can be operable to receive the wave at the selected position after the wave has been reflected from tissue in the bone
Implementation Method 2
The module can be operable to determine a distance from the depth gauge to the tissue in the bone based on times at which the wave is transmitted and received
Data Source
AI summary
A method for estimating at least one of a fastener-hole depth and a fastener length prior to forming a hole in a bone can include selecting a position on a proximal side of a proximal cortical bone layer for forming the hole, transmitting a transmitted wave into the bone from the selected position, and receiving a reflected wave at the selected position after the transmitted wave has been reflected by a distal cortical bone layer. The method can further include determining a distance from the selected position to the distal cortical bone layer based on times at which the transmitted wave is transmitted and the reflected wave is received, and estimating the at least one of the fastener-hole depth and the fastener length based on the distance to the distal cortical bone layer.