Chapter 31: Orthoses for persons with Postpolio syndrome Flashcards Preview

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Flashcards in Chapter 31: Orthoses for persons with Postpolio syndrome Deck (21)
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1
Q

What is postpoliomyelitis syndrome?

A

Confirmed history of paralytic polio characterized by an acute illness with fever and usually asymmetrically distributed, flaccid paresis of a varying number of muscle groups. Evidence of motor neuron loss on neurological examination iwth signs of residual weakness, atrophy, loss of tendon reflexes, and intact sensation.
Period of partially to fiarly complete neurological recovery followed by neurological and functional stability for at least 15 years.
New or increased muscle weakness or abnormal muscle fatigability (decreased endurance), with or without generalized fatigue, muscle atrophy, or muscle and joint pain.
Gradual symptoms, but sometimes a sudden onset that persists for 1 year.
No other medical diagnosis to explain the symptoms.

2
Q

What are the risk indicators for the development of PPS?

A

More severe intial polio paresis, better recovery from the acute polio, more severe residual impairments, contraction of acute polio at older age, number of years elapsed since acute polio, increasing age, and female gender.

3
Q

Paralytic poliomyelitis develops in what percent of polio virus infections? What must it invade and destroy?

A

.1%-2%
It invades the central nervous system and destroys the motor neurons in the spinal cord, causing an acute, usually asymmetrically distributed, flaccid paresis.

4
Q

What happens after acute poliomyelitis?

A

Muscle function usually recovers partially to fairly completely due to extensive reinnervation of denervated muscle fibers through collateral sprouting of axons from motor neurons that survived the acute phase and regained their function.
Motor units may increase 5 - 8X there size.
Strength also improves because of muscle fiber hypertrophy, with fiber areas increasing up to twice their normal sizze.

5
Q

Why does muscle fiber hypertrophy develop after acute polio?

A

It’s in response to the relatively high loads on paretic muscles in performing activities of daily living.

6
Q

What is the origin of PPS?

A

It is unknown, but the leading hypothesis is that excessive metabolic stress on remaining motor neurons over many years eventually causes premature degeneration of the nerve terminals that were newly formed through reinervation.

7
Q

What is the central issue of PPS?

A

Graual loss of muscle function, that is new weakness.

8
Q

What is important to realize about the acute stage of Polio?

A

The neurons affected was probably more widespread then clinically apparent, and paralytic and nonparalytic polio are not two different forms of polio.

9
Q

What is the major complaint of patients with PPS?

A

Fatigue.

10
Q

What are the possible causes of fatigue in patients with PPS?

A

Impaired calcium knetics. Altered calcium levels may account for disturbances in excitation-contraction coupling of actin and myosin filaments, decreased capillary density, reduced oxidation and glycolytic enyme potentials, impaired voluntary muscle activation, increased neuromuscular transmission defects in degenerating nerve terminals, and degeneration of neurons of the reticular formation and basal ganglia.

11
Q

What is some support for the theory of muscle overuse in patients with PPS?

A

Elevated levels of serum creatine kinase related to the distance walked during the previous day
Also a predominance of type I fibers in lower leg muscles supposedly due to fiber type transformation from chronic overload.
Another factor may be poor cardiorespiratory condition
Lower concentrations of some oxidative enzymes in the muscles of polio subjects have been reported.

12
Q

What are three conservative ways to reduce the overuse and rebalance the capacities and demands?

A

Exercise
Assistive devices
Lifestyle changes.

13
Q

What will exercise do to help with muscle overuse?

A

optimize cardiorespiratory fitness and may add to the patient’s sense of well-being.
Exercise should not be fatiguing and performed at submaximal levels to avoid overloading the limited muscle capacity.
It can improve load capacity, and muscle strength.
Functional training may be useful to improve the efficiency of ambultation.

14
Q

What type of lifestyle changes should be done to prevent overuse?

A

Pace activities

Take rest intervals

15
Q

What TYPES of orthosis should be considered for patients with PPS?

A

Leg orthoses for walking and standing with weak musculature.
Orthoses to protect painful joint degeneration and joint instability as a results of prolonged and biomechanically altered loading of hypoplastic and deformed joints.

16
Q

What are some good orthoses for PPS in a patient with calf weakness?

A

Preimpregnated carbon composite AFO with dorsifexion stop hinges and posterior springs to enable ankle rocker in calf weakness. The anterior part of the footplate is flexible and made of kevlar to enable forefoot rocker.

17
Q

What is a good orthosis for PPS in a patient with calf weakness and a foot deformity?

A

Preimpregnated carbon composite AFO with custom-made inner boots for severe and partially fixed foot deformity. Wearing comfort is enhanced by optimizing the distribution of forces applied to correct the foot in this manner.

18
Q

What is another orthosis for PPS in a patient with calf weakness?

A

Custom-made posterior leaf sping AFO for calf weakness. The strength of the spring is determined by varying the number of layers of preimpregnated carbon to the layers of kevlar.

19
Q

What’s the advantage of a preimpregnated carbon composite KAFO compared to a metal and leather KAFO?

A

Lighter weight
Improved fit
Greater deformity correction
Use of normal shoes

20
Q

When should a KAFO with mechanically operated stance-phase control knee joints be desired?

A

Patients with weak quadriceps and knee instability/deformity

21
Q

When should a KAFO with an offset knee joint be used?

A

Patients with hyperextension

However, it should allows some hyperextension to allow for stability in the case of quad weakness.

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