Automatic external fixator

• Grant number: 17/01851-5
• Support Opportunities: Research Grants - Innovative Research in Small Business - PIPE
• Start date: December 01, 2017
• End date: April 30, 2021
• Field of knowledge: Engineering - Biomedical Engineering - Medical Engineering
• Principal Investigator: Osmar Vogler
• Grantee: Osmar Vogler
• Company: Selaz Indústria e Comércio de Aparelhos Biomecânicos Ltda
• City: São José dos Campos
• Associated researchers: Guilherme Pelosini Gaiarsa
• Associated research grant: 15/08611-4 - Automatic external fixator, AP.PIPE

Abstract

External fixation of limbs consists of a surgical technique of orthopedics employed to stabilize bones and soft tissues through a structure external to the body and components that connect the bones to the fixator. The external fixators have dimensional variations, being able to be used in different regions of the body, besides different degrees of complexity and therapeutic resources. Thus, such devices can be used in treatments for stabilization and reduction of fractures, removal of osteomyelitis and bone tumors, corrections of deformities and vicious consolidations, among other applications. Such treatments last for several months, at which time the patient returns to the doctor countless times for therapy follow-up. Such follow-up occurs in the form of adjustments in the structure of the external fixator based on x-ray images of the limb. In addition to this mechanism, there are cases in which the patient makes the adjustments in the structure in order to follow the doctor's prescriptions. It is observed that the longer the treatments and the more complex the movements to be performed, the greater the chances of obtaining unwanted results at the end of the therapies, culminating in new surgeries or residual deformities. Such types of outcomes occur mainly because of errors in adjustments, whether physician or patient, because accurate planning of therapy is often neglected over time. Thus, an automatic system, which requires less frequent human interventions, could maximize the chance of success in such types of treatment. The whole load of planning of movement, as well as the accomplishment of the movements, would be left for a computer to perform, being incumbent on the physician to analyze and follow what was foreseen at the beginning of the treatment. In addition to performing the movements in a thorough manner and planning all the steps, such an automatic fixator would make it possible for fewer visits to the doctor, as well as fewer exposures to the radiation, a fact that occurs when the physician requests radiographic images of the member. From the typical forms in which external fixator systems are made, heavy materials such as stainless steel and aluminum are used. The company proposing has already developed most of the pieces in composite material, using Carbon fiber. Thus, the system would have additional benefits of lightness and radiolucency because Carbon fiber is permeable to X-rays. In order to provide the structure of the external fixator with automatic movements, the insertion of actuators is foreseen. These will be positioned on each of the six rods, which refers to the concept of the Stewart platform or Hexapod. The actuators will be electric motors, whose torque and power compatible with the needs of the therapy. Such motors will be controlled by means of an excitation circuit, which is controlled by a microcontroller. The latter will be responsible for storing the trajectory to be followed, as well as to sample position data of the motors and to provide the necessary feedback to the auxiliary treatment software. The automatic fixator communication with the outside world will be through wireless technology. From the point of view of the doctor and the patient, the treatment can be accompanied by a personal computer or smartphone, since all communication will be wireless and the data will be available for consultation, even in real time. The mastery of such technology opens up a range of possibilities both for marketing and for research. In addition to introducing a very innovative product, it is a tool capable of producing success in the therapy of many citizens, improving productivity, self-esteem and quality of life for these people. (AU)