Differential Expansion Driver for Uniform Spinal Implant Adjustment
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Solution Overview
Problem
Current spinal fusion procedures face challenges in precisely adjusting expandable implants due to uneven torque distribution during adjustment, which can lead to uneven expansion and potential complications in restoring natural spinal curvature.
Innovation Solution
The use of a differential gear system in an expansion driver that includes bevel gears and coaxial driver shafts allows for equal torque distribution between multiple actuators of an expandable implant, ensuring simultaneous and equal adjustment of the implant's dimensions, such as height, width, and angle of lordosis, by automatically transferring torque to the actuator experiencing less resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional expansion driver is used to adjust expandable implants, then the implant can be expanded, but the torque distribution is uneven leading to uneven expansion and potential complications
Solution Approach 1:
The driver shaft is segmented into multiple independent drive shafts (first drive shaft, second drive shaft, etc.), each capable of receiving and transmitting torque independently to different actuators on the implant. This segmentation allows for independent control and uniform torque distribution to multiple expansion points simultaneously
Solution Approach 2:
A differential mechanism is introduced as an intermediary component between the handle and the drive shafts. This differential automatically distributes torque to the drive shafts based on resistance, ensuring equal torque delivery to multiple actuators without requiring manual adjustment, thereby achieving uniform implant expansion
2Ease of operation
If manual torque adjustment is used during implant expansion, then the surgeon can control the expansion, but it is difficult to ensure equal torque distribution to multiple actuators simultaneously
Solution Approach 1:
The differential mechanism is designed to automatically self-regulate torque distribution without requiring manual intervention. As the surgeon applies torque through the handle, the differential autonomously directs equal torque to multiple drive shafts based on real-time resistance feedback, eliminating the need for manual torque balancing while ensuring precise equal distribution
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 enables precise and even adjustment of expandable implants, reducing the risk of complications and ensuring accurate restoration of spinal curvature by ensuring equal torque distribution, thus facilitating more effective and reliable spinal fusion procedures.
Implementation Method 1
a differential for an expansion driver may include: at least one bevel gear, a first drive gear connected to a first output shaft, and a second drive gear connected to a second output shaft, the at least one bevel gear rotatably connected to a first drive source and configured to rotate around a first axis, wherein upon a rotation of the at least one bevel gear about the axis by the drive source, a torque will be transferred from the at least one bevel gear to one or more of the first drive gear and the second drive gear
Data Source
AI summary
This disclosure includes an expansion driver for adjusting expandable implants, the expansion drivers includes: a first driver having a first gear disposed at a first end thereof; and a second driver having a second gear disposed at a first end of the second driver; and a handle operably connected to the first driver and the second driver, the handle having at least one bevel gear rotatably attached thereto, the at least one bevel gear engaging each of the first gear and the second gear; wherein upon a rotation of the handle a torque is applied to at least one of the first driver or the second driver.