ManiFlex, A dynamic orthosis for children with cerebral palsy
The video shows the process and final result
The video shows the process and final result
The flexpoints on the joints
Front view ManiFlex
Software in wich the orthopedic technician developes the features of the orthosis
Child with the ManiFlex
What it does
Hypertonia in the upper limb of children with cerebral palsy causes serious physical damage. Traditional orthoses that counteract hypertonia have many shortcomings. Maniflex offers a new functional and integrated solution with the unique properties of TPU.
Within the orthopedic sector many traditional methods are used for the production of custom orthopedic products. Orthopedic companies are trying to make a transition to new production techniques using additive manufacturing (AM). Unfortunately most of these new products make little use of the many benefits of AM. That is why I went through materials research and prototyping to find out how AM and specifically TPU can really make a difference for both patient and producer. This research has led me to the condition cerebral palsy, in which spasticity causes many problems and where the current orthoses are outdated.
How it works
The ManiFlex is designed to be manufactured by an orthopedic technician. They can upload the arm and hand into a software using a 3D scanner. The orthosis can then be placed around this anatomical shape. In the software the orthosis can be fully personalized according to the clinical data measured by a physician specialist and the personal wishes of the patient. TPU has the unique property that allow it to be both flexible and rigid due to a variation in wall thickness. Flex points now replace traditional mechanical hinges and can provide specific resistance by adjusting their thickness. A thicker rib around the orthosis ensures a stiff and stable whole. The fold points are always along both sides of the joint. The material is porous which is suitable for skin contact. Despite of the good feature of the porosity one opted for an open design and ventilating zones. The velcros can be cut to fit and are easy to remove for cleaning and recycling.
The process started from MJF printing with TPU and how it can be implemented in custom orthopedic. Therefore prototyping research has been conducted into how TPU can replace or improve existing functions in orthoses such as hinges, cushioning, support and limited movement, closures and padding with AM and TPU. For this, exploratory prints were made with an FDM & MJF printer in which various new and iterative concepts were compared with each other and with existing solutions. From the exploration limited movement and hinged functions leaded to the opportunity of a dynamic orthosis. The design of the orthosis started off with iterative design of finger segments which are the most crucial elements for the functionality of a hand. The same happened for the base of the orthosis, other joints in the hand such as the wrist,.. and closing mechanism. Detailed designs were used for functionality testing. Tensile and compression tests were used to test strengths and durability, in which different benchmark samples with different wall thicknesses can be compared. All prototypes had to meet the medical requirements and human aspects. These were researched in advance and documented through interviews with users and experts, strength tests and in-depth research.
How it is different
Two types of orthoses are currently prescribed for spasticity in the upper limb of children with cerebral palsy. First there is the static orthoses that blocks the forces but in which the patient is completely trapped and experience a lot of pain because of high tensions. The second option is a partly dynamic orthosis in which expensive patented hinges are placed along the wrist. The ManiFlex is a new dynamic orthosis that allows movement in all joints and of which each individual joint can receive a specific resistance. This allows the patient to perform functional tasks and the high and alternating spasticity is accommodated instead of blocked. Each finger is individually movable, which is a great advantage for everyday tasks. Using a 3D scanner and software, the orthopedic technician can instantly develop a unique and new product that is fully customized and meets all the needs and wishes of the patient.
There are still many further developments to be made in terms of the printing process. At the moment, the print direction must be taken into account and unexpected breakage often occurs. HP and Lubrisol are working on this development and have good prospects. This is very promising and will ensure that it becomes a full-fledged product that is robust and durable. Coloring is also not possible at the moment and the finishing methods are not yet ready. But there are future plans for this. When the material is fully developed, the velcros can also be replaced by TPU.