Instrumented Adjustable Implant for Controlled Bone Lengthening
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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 lack efficient load monitoring and control.
Innovation Solution
An adjustable implant with smart electronics, including a housing, movable adjustable portion, load cell, actuator, sensor, and controller, allows precise and controlled bone lengthening or shortening with real-time load monitoring and adjustment via external devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If external fixation frames are used for limb lengthening, then bone sections can be moved apart at a controlled rate allowing new bone to regenerate, but the frames are bulky, painful, and prone to infection
Solution Approach 1:
The patent places the distraction mechanism inside the patient's bone (intramedullary positioning), nesting the device within the bone structure itself rather than outside. This eliminates the need for external fixation frames that pass through skin, thereby reducing infection risk while maintaining controlled distraction capability
Solution Approach 2:
The patent extracts the distraction mechanism from the external environment and relocates it inside the bone. By removing the external frame structure and pins that penetrate the skin, the solution eliminates the primary sources of infection and patient discomfort while preserving the core function of controlled bone separation
2Ease of operation
If external fixation frames are used for limb lengthening, then bone sections can be moved apart at a controlled rate, but the frames are bulky making it difficult for patients to sit, sleep and move
Solution Approach 1:
By nesting the distraction mechanism within the bone's medullary cavity, the device eliminates the need for external frames that interfere with patient movement. The intramedullary positioning allows patients to sit, sleep, and move freely without the bulk and constraints of external fixation structures
Solution Approach 2:
The patent removes the external frame structure entirely and relocates the distraction mechanism inside the bone. This extraction of the device from the external environment eliminates the physical bulk that hinders patient mobility while maintaining the controlled distraction function
3Ease of operation
If intramedullary lengthening devices are used, then patient comfort is improved, but load monitoring and control are insufficient
Solution Approach 1:
The patent incorporates load cells and sensors that continuously monitor forces and positions during distraction. This feedback is transmitted to an external device that provides real-time information about bone loading and distraction progress, enabling precise control and adjustment of the distraction rate while maintaining patient comfort
Solution Approach 2:
The patent replaces simple mechanical intramedullary devices with an instrumented system that uses electronic sensors, load cells, and wireless communication. This substitution transforms a passive mechanical device into an active, monitored system that provides precise load measurement and control while maintaining the comfort benefits of intramedullary positioning
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 implant provides a comfortable, infection-free solution for limb lengthening with precise control and real-time data monitoring, enhancing patient comfort and treatment efficacy.
Implementation Method 1
a load cell within the housing for measuring a load imparted on the implant during movement of the adjustable portion relative to the housing or during movement of a bone relative to the housing
Implementation Method 2
a sensor positioned adjacent to the actuator and configured to monitor an angular position of the actuator
Data Source
AI summary
Aspects of the disclosure relate to an adjustable implant configured to be implanted into a patient that includes an adjustable portion moveable relative to a housing. The adjustable implant may include various smart components for enhancing operation of the implant. Smart components may include a controller for managing operations and a transducer for communicating ultrasound data with an external interface device. Additional smart components may include a load cell within the housing for measuring an imparted load; a sensor for measuring angular position of the adjustable portion; a dual sensor arrangement for measuring imparted forces; a reed switch; a half piezo transducer; and an energy harvester.