DYNAMIC AFOs and other high temperature molded DYNAMIC ORTHOTIC SYSTEMS

The development and specific use of DAFOs is dealt with elsewhere, but my earliest history came in 1969-70 as a young therapist searching for ways to have "more hands" available in treatment. Soft adaptations to shoes that managed excessive toe curling freed my hands to assist movement elsewhere. The current evolution has come through a period of "inhibitive casting" to the present over the ankle, extremely thin and flexible support system. This assists the foot and ankle in stabilizing movements around a defined midline orientation, using specific support and enhancement of natural dynamic arching systems. Quite by accident, we have discovered that flexible is more tolerable. Children who are so stiff that they have never before had successful orthotic wear, repeatedly find comfortable support in ultra thin DAFOs.

Polypropylene, though a very old plastic, is used because of 2 specific polimerization properties which are helpful.

1. IT STRETCHES - This allows the plastic to remain relatively thicker under the sole, around the heel and over the ankle for greater stability while being pulled much thinner over the top of the foot and under the toes for better tolerance and movement possibilities.
   
   
2. IT HAS EXCELLENT MEMORY - Due to the nature of the plastic polymer, when distortion occurs, the plastic has a strong rebound energy to return to it's original shape, even when it is pulled ultra thin . This rebound memory is quite helpful as a gentle but consistent assist to active movement control and alignment toward a midline positional orientation. Another interesting and helpful property of the plastic is that the greater the degree of distortion, the stronger the polymer rebound energy becomes. There is high dynamic corrective energy against extremes of distortion or extremes of joint positioning. The beginning thickness of only 2 mm or 3/32 inch mandates generous flexibility which makes the brace fit as a "flexible exoskeleton" rather than a noticeable appliance. Extreme detail to precise volume, total contact, subtalar neutral alignment and midline foot/ankle orientation in the plaster positive mold produce a "glove like" fit. A woman of 34 years with moderate spastic diplegia once described her DAFOs feeling like a "pair of control panty hose". She then stated that with them on, she no longer needed to "worry about" her feet. If contact produces generalized rather than specific point support, the sensory experience will more likely be experienced 3 - dimensionally throughout the supported body part. The combination of moderate tissue compression, precise total contact and very flexible support appears to provide very helpful organization to movement and postural control.

Cascade Prosthetic and Orthotics in Bellingham, Wa. and many others have continued to explore the incorporation of greater flexibility into more traditional bracing systems with many good successes. Flexible body jackets constructed of polyethylene rather than more thick polypropylene are often tolerated much better in children who have some amount of active of active shoulder/trunk/hip movement. Flexible polyethylene body jackets provide excellent control in the vertical dimension and the brace and person move together. Again the principle of flexible exoskeleton emerges. Traditional rigid body jackets can cause problems of pressure and rubbing because the person moves within a rigid orthosis.

Flexible polyethylene circumferencial leg extension braces have also experienced some very good success. Interestingly, when they are pulled of less flexible material, tolerance and usefulness often decrease dramatically. Recent exploration into 2 new areas of molded high temperature orthoses are showing good preliminary results in the management of previously very difficult problems. A molded total body orthosis for very severely handicapped youngsters has been tolerated very well by a young man and a second prototype is in process. These are fabricated to permit slight twist flexibility and rebound into original orientation. Another recent development is an ultra thin polyethylene brace designed to provide flexible and precise positional support, stability and fine movement control to thenar, hypotenar, thumb/index finger web space and the dynamic palmar arches. It is designed to be worn alone or under a SPIO Lycra Glove.

Back Copyright © 1997 - Nancy Hylton, P.T