Hand Orthoses For Complex Cases With New Technology

Michael Ceder, CPO


Patients who need upper limb orthotics present to our orthopedic department often have problems that are difficult for occupational therapists to solve. Many times this is due to lack of materials and/or lack of knowledge of manufacturing skills. One reason could also be that prefabricated orthoses do not work satisfactorily. This particular group of patients is often spastic with more or less intractable deformities.

When treating complex upper extremity patients there are many difficulties to overcome, but one important element is a good shape of the orthosis. This increases the potential acceptance of the device, also increases comfort of an orthosis and consequently the compliance of usage.

Traditionally, orthoses for complex upper extremity problems are made by using a plaster mold or manufactured directly on the patient with a low temperature plastic. In both methods, achieving the desired final position of the hand and finger joints is difficult and time consuming for both the patient as well as the manufacturer.

Since 2008, we have worked with CAD/CAM technology and accumulated experience. The technology has a great potential for correcting, copying and mirroring any body shape. It is also possible to effectively save digital images and reproduce them.

1) New technology has made the process easier in many ways especially for the patient, but also for us as professionals. It is rapid, comfortable, and precise.

With CAD/CAM it is possible to:

  • Make a copy
  • Mirror shape
  • Easy to save and start up again
  • Change the volume
  • Change the angle and rotate
  • Merge together different forms
  • You get a good history of the modeling

 

One difficulty with CAD/CAM has been to scan patients who cannot keep their body still and/or maintain the desired position for the relatively short time it takes to scan. Hands have been especially hard to deal with when there are many parts to be held in the right position at the same time, and this is not easy with plaster either. As a result, we have developed tools to facilitate this problem and achieved good results in producing all kinds of orthoses from head to foot, for all types of patient cases. Patients are delighted with this development.

It is world news that with this tool we now can scan 100% of our patients with satisfactory results. We have developed bags for the hand and foot in different sizes. By adapting the bag over the patients hand and using a vacuum technique, we stabilize the body part of interest in the position desired and are then able to scan the patient without further correction or disturbing the scanning process. Because the bags are transparent, the scanner ignores the plastic. The acceptance from the patients is very good and the scanning runs smoothly. If we need to change the position, it is simple to let the air go into the bag, reposition and stabilize in a new position.

The use of foam molds, instead of plaster, has also forced us to consider new materials and manufacturing methods. Synthetic felt has been a common material for the last years in many ways at our company, and is a material made of 100% Polyester. We have found it suitable for hand orthoses. Felt is a light material, easily shaped, washable, has good breathability, and also good acceptance and comfort. However, felt has the negative side of being difficult to adjust with heat and is time consuming in production.

Some of the advantages of CAD/CAM are that, even if we were not scanning at the perfect angle, the software makes it possible to alter and produce orthoses in the desired position. Children are growing individuals who frequently require new molds for manufacturing. Contracture treatment with the goal of improving angles, often requires new molds when, due to treatment, conditions are improving. CAD/CAM allows us to adjust models for growth or change in angles without making a new model.

Until now, I have been treating patients with 33 different WHFO's. These patients include mostly Cerebral Palsy diagnoses, but also strokes, acquired brain injuries, muscle diseases, and total paresis. I have also used the technique for manufacturing AFO's for the same types of diagnoses and achieved similar result as with the hand patients. My experience in using this manufacturing method is very positive and I am happy and proud to say that it is now possible to scan 100% of my patients. Image 2 , Image 3 , Image 4 , Image 5 , Image 6 , Image 7 .

Michael Ceder is affiliated with Teamolmed Orthopedic Department, Jönköping, Sweden