Flat-Plate Bone-Lengthening Implants With Compact Nested Lead Screws
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Solution Overview
Problem
Existing distraction osteogenesis devices are limited by their size and shape, restricting the implantation site and procedures that can be performed.
Innovation Solution
An adjustable implant system with a drive assembly and lead screw mechanism that allows for controlled, precise translation of bone segments using a non-invasive external control, enabling distraction and compression procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional distraction osteogenesis devices are used, then bone lengthening can be achieved, but the device size and shape limit the implantation site and procedure flexibility
Solution Approach 1:
The lead screw is disposed at least partially within the first and second portions of the implant, with the drive assembly positioned within the first portion. This nested configuration allows the distraction mechanism to be compactly integrated within the implant structure, reducing overall device volume while maintaining functionality at various implantation sites
Solution Approach 2:
The implant is divided into a first portion and a second portion that can axially translate relative to each other. This segmentation allows the device to be adapted to different bone segments and implantation locations while keeping each portion compact in size
2Measurement precision
If a lead screw mechanism is used for bone translation, then precise control of distraction rate is achieved, but the mechanism requires significant space within the implant
Solution Approach 1:
The lead screw is integrated within the first and second portions of the implant, with the drive assembly nested within the first portion. This nested arrangement provides precise distraction control through the lead screw mechanism while minimizing the space required by housing these components efficiently within the compact implant structure
3Ease of operation
If an external drive mechanism is used to control bone distraction, then non-invasive adjustment is possible, but the coupling between rotational and axial motion requires complex gearing
Solution Approach 1:
The drive assembly is configured to convert rotational motion to axial translation of the second portion relative to the first portion. By integrating the drive assembly within the first portion and directly coupling it to the lead screw, the design simplifies the mechanical transmission path, reducing the need for complex external gearing while maintaining non-invasive adjustability
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 controlled bone lengthening and compression with high precision and flexibility, allowing for regular distraction rates and improved surgical outcomes.
Implementation Method 1
a lead screw disposed at least partially within the first and second portions along the second axis. The lead screw is rotatably coupled to the drive assembly such that rotational motion about the first axis drives rotational motion of the lead screw about the second axis, thereby causing the second portion to axially translate along the second axis relative to the first portion
Data Source
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AI summary
Provided herein is an adjustable implant configured to non-invasively guide bone growth in a patient. The adjustable implant includes a first portion (102; 202; 302) configured to couple to a first bone segment and a second portion (104; 204; 304) at least partially disposed within the first portion (102; 202; 302) and configured to couple to a second bone segment. The adjustable implant includes a drive assembly (110; 210; 310) configured to be transcutaneously actuated, and to drive rotation of a gear assembly (120; 220; 320) configured to rotate about a first axis (A1), and drive axial translation of the second portion (104; 204; 304) along a second axis (A2). Non-invasive actuation of the drive assembly (110; 210; 310) therefore causes the adjustable implant to distract or retract along the second axis (A2).