Extramedullary Bone Distractor With Integrated Gear Drive
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Solution Overview
Problem
Existing limb lengthening techniques using external fixation frames are bulky, painful, and prone to infection, while intramedullary devices are limited by inadequate canal space in some patients.
Innovation Solution
An extramedullary distraction and compression device with a distractor housing a drive system and anti-rotation features, allowing controlled bone lengthening and compression via a non-invasive, extramedullary approach, suitable for patients with inadequate canal space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If external fixation frames are used for limb lengthening, then bone separation control is achieved, but the device becomes bulky and causes patient discomfort
Solution Approach 1:
The invention extracts the drive system from the traditional external fixation frame structure and places it within an intramedullary nail, separating the lengthening function from the external frame. This allows the external frame to be removed or minimized, significantly improving patient comfort while maintaining precise bone separation control through the internal drive mechanism
Solution Approach 2:
The drive system is nested within the intramedullary nail structure, with the distractor mechanism housed inside the nail body. This nested configuration allows the complex drive system to be contained within a compact intramedullary device, eliminating the need for bulky external frames while preserving precise lengthening control
2Measurement precision
If external fixation frames are used for limb lengthening, then bone separation control is achieved, but infection risk increases due to pin tracts
Solution Approach 1:
The invention removes the external pin tracts that serve as infection pathways by placing the entire drive system and distractor mechanism inside the intramedullary nail. This eliminates the open wounds and pin sites that are prone to infection, while maintaining controlled bone separation through the internal mechanism
Solution Approach 2:
The intramedullary nail serves as an intermediary structure that houses the drive system, replacing the need for external pins and wires. This intermediate containment structure protects the sterile internal environment from external contamination while still enabling precise bone lengthening control
3Ease of operation
If intramedullary lengthening devices are used, then patient comfort is improved, but the device cannot be used in patients with inadequate canal space
Solution Approach 1:
The intramedullary nail is designed with dynamic adjustment capabilities, allowing the drive system to be adapted to different bone canal sizes. The modular design and adjustable components enable the device to accommodate varying anatomical dimensions while maintaining the comfort benefits of an internal device
Solution Approach 2:
The device incorporates adjustable parameters such as nail diameter, drive system configuration, and distractor positioning that can be modified to suit different patient anatomies. This parametric adaptability allows the same intramedullary platform to be used across a range of bone sizes and canal spaces
4Volume of moving object
If a drive system is housed within the distractor, then device compactness is improved, but manufacturing complexity increases
Solution Approach 1:
The drive system is segmented into modular components that can be manufactured separately and then assembled within the distractor. This segmentation allows each component to be produced using optimized manufacturing processes for that specific part, reducing overall manufacturing complexity despite the compact integrated design
Data Source
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AI summary
An extramedullary biocompatible implant (100) for moving bone in a patient's body includes: a first plate (102) configured to be attached to bone at a first location; a second plate (108) configured to be attached to bone at a second location; and a distractor (106) extending from the first plate (102) and being at least partially contained within the second plate (108), where the distractor (106) houses a drive system (200) including a driver (202) and a gear system (204) coupled with the driver (202), and where the drive system (200) is configured to cause translation of the second plate (108) relative to the first plate (102).