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Spasticity and Seating: Spasticity is a motor disorder often seen in clients with head injuries, spinal cord injuries, MS and cerebral palsy. It is characterized by velocity-dependent resistance to a passive stretch resulting in exaggerated tendon jerks and hyperexcitability of the stretch reflex. The functional impact of spasticity can include interference with mobility and joint range of motion which can disrupt functional tasks of eating, wheelchair mobility, and all other activities of daily living which require fine or gross motor control. Pain and discomfort are common side effects of spasticity leading clients to limited sitting tolerances and overall limitation in activity participation. Baclofen Pumps were introduced to deliver a gamma-butyric acid into the intrathecal space of the spinal cord via a catheter from an implanted pump with resulting decreases in spasticity. Clients must undergo surgery with anesthesia for placement and further surgery may be required for complications or battery replacement. It may take 6 months to 1.5 years for a maintenance dose to occur. Baclofen pumps are recommended for clients with severe spasticity and/or rigidity that has lasted greater than one year. Botox injections function by exerting a paralyzing effect on a specific targeted muscle by producing a chemical denervation. It therefore has a very targeted effect and only a limited number of sites can be targeted with each injection. There is potential for antibody formation therefore limiting lifetime changes. It also has a relatively short time frame for effectiveness over 2-3 months, and as such changes in tone may reoccur if ongoing injections are not provided. With both of the above interventions, it is critical to observe the client in a seated posture before interventions to determine “normal” pre medical intervention body postures and positioning with the influence of spasticity. This will help determine possible ongoing requirements for the seating system based on the lifespan of the medical intervention. Although supports may initially be reduced, ongoing tonal changes may return and therefore supports must be able to be added again as required. Control points for postural support must be monitored as potential sites for pressure points if spasticity returns and the pressure against control sites becomes too great. Therefore the most important factor of seating clients post medical intervention is allowing for adjustability and flexible systems. Fixed systems with lack of ability to change or adjust control points, angles or materials will result in frustration for all involved. One possible side effect of intervention related to seating is hypotonia. Some clients develop the need for increased support from their seating system due to a loss of head and trunk control as well as stability due to decreased pelvic and lower extremity control. Therefore a seating system may change from one of spasticity control and more anterior pelvic guides to full posterior and lateral support with tilt in space components. Where a pelvis was once held in anterior pelvic tilt with spinal lordosis due to spasticity, a “slumping” of the spine and pelvis may occur with increased posterior pelvic tilt and forward kyphosis of the spine. Posterior support must then be added, but made of an adjustable support medium in order to readjust control points if spasticity returns. The same may be seen in the lower extremities where initial control was required in maintaining leg abduction. Post intervention, adductor control may be necessary due to low tone, but maintaining abductor positioning may be required for future changes. Foot positioning is also critical. Pre intervention supports may have been required to control full extensor patterning whereas post intervention control of external rotation of the leg and inversion of the feet is necessary. Pelvic positioning devices must be carefully monitored not only for control, but also for intervention with pump sites. Angle of pull may need constant monitoring to maintain support for the pelvis throughout changes in spasticity levels. There can also be a tendency toward pressure sore formation as a result of loss of muscle bulk, as well as decreased muscle tone changes, as previous high tone often assisted with pressure alterations. Therefore seating may indeed require radical changes to support areas which are of less concern prior to medical intervention. Higher pressure relief cushioning not only under the pelvis but at other areas of body contact is therefore critical to be assessed as well as the possible need for tilt in space to alter body positioning and pressure points through out the day. Other concerns also include weight gain due to decreased muscular activity. Changes in muscle bulk as well as weight shifting to areas of reduced activity may result in adjustments required for width or length of the seating system. Overall, it is therefore recommended that seating systems being provided for clients undergoing medical interventions have the following components to allow for ongoing adjustments to tonal changes:
It is therefore critical that any seating interventions are developed over a three month period post medical intervention before final prescription. This will allow for transitional changes noted with Baclofen pumps, and for determination of success with Botox injections. However, even at this point in time further adjustments may be necessary and therefore ongoing flexibility is required. These clients therefore must be followed closely for ongoing changes which may occur up to a year and a half post intervention. It is also imperative that seating technicians work closely with the PT and OT who may be working with the client post intervention on muscle strengthening, trunk control and range of motion. Seating interventions need to be cognizant of desired outcomes for postural stability versus improved self initiated postural control. |
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