Intramedullary Nail Rotational to Linear Motion Convertor
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Solution Overview
Problem
Existing osteodistraction devices face challenges such as lack of reversibility, insufficient strength, inadequate distraction force, difficulty in implantation, and patient immobilization, which hinder effective bone lengthening and reconstruction.
Innovation Solution
A system comprising an intramedullary nail with a rotational to linear motion convertor mechanism and a driving shaft, allowing for external operation to vary the distance between bone segments by linearly displacing a slider attached to the second bone segment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a telescoping plate with motor is used for bone lengthening, then bone lengthening can be achieved, but the device complexity increases and requires nailing
Solution Approach 1:
The patent extracts the motor and control mechanisms from the intramedullary nail structure and places them in an external drive assembly. The nail itself becomes a simple telescoping structure with proximal and distal segments that can be driven apart by the external motor, eliminating the need for complex internal motor integration while maintaining bone lengthening capability
Solution Approach 2:
The patent introduces an external drive assembly as an intermediary between the surgeon and the bone segments. This external assembly includes a motor that drives a mechanism to separate the proximal and distal nail segments, providing controlled bone lengthening without requiring the nail itself to be complex or require nailing for motor integration
2Productivity
If distraction force is increased for better osteodistraction, then bone lengthening efficiency improves, but the strength of the nail and risk of failure increases
Solution Approach 1:
The patent employs a dynamic telescoping mechanism where the proximal and distal segments can be controlled to move apart at regulated rates. The external drive assembly allows for adjustable distraction forces that can be modified during treatment, enabling optimized bone lengthening while maintaining nail integrity through controlled, progressive separation rather than excessive static force
Solution Approach 2:
The patent implements periodic or controlled distraction cycles where the nail segments are separated at regulated intervals and rates. This periodic action allows the bone to adapt to the distraction forces over time, maintaining nail strength while achieving efficient bone lengthening through repeated, controlled separation and healing cycles
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
The system enables efficient management of skeletal deformities and bone fractures through controlled bone distraction, compression, and transport, while maintaining stability and resisting torsional and bending deformations.
Implementation Method 1
a rotational to linear motion convertor mechanism, and a transmission configured to transmit rotational motion and power at an angle; wherein output member of the said transmission operatively couples with input part of rotational to linear motion convertor mechanism
Data Source
AI summary
A system for varying distance between bone segments comprises an intramedullary nail (100) and a driving shaft (210). The intramedullary nail (100) comprises a head (110) attached relative to a first bone segment (410); a housing (120) attached with the head (110); a rotational to linear motion convertor mechanism (140) having an input part and an output part (160); and a transmission (130) having an input member (131) & an output member (133), operatively coupled with input part (150) of rotational to linear motion convertor mechanism (140) and configured to transmit rotational motion and power at an angle. Further, at least a portion of the rotational to linear motion convertor mechanism (140) is contained in the housing (120) and the output part (160) is attached relative to a second bone segment (420). Additionally, the driving shaft (210) is configured to detachably connect with an input member (131) of the transmission.