Denervated Muscle

Question 1

What is a denervated muscle

Answer 1

every motor unit in a muscle

Question 2

what is a partial denervated muscle

Answer 2

state of the whole muscle and not the initial muscle fibers, some fibers remain innervated

Question 3

what is a motor unit

Answer 3

anterior horn cell, axon and all the muscle fibers it innervates

Question 4

what are some characteristics of denervated muscles

Answer 4

• loss of voluntary control and reflexes
• progressive muscle atrophy
• other histological changes such as degeneration of the NMJ and changes in the resting membrane potential
• over time the muscle fibers are gradually replaces and adipose tissue

Question 5

what is reenervation influenced by

Answer 5

• integrity of the nerve matrix and muscle fibers
• local environment which is impacted if edema and venous stasis are present
• regrowth is 1mm per day or 1 inch per month

Question 6

what are pros to simulation of denervated muscle

Answer 6

contraction of the muscle may decrease edema and venous statis, and may decrease muscle atrophy

Question 7

what are the cos to stimulating deneveratd musle

Answer 7

• contraction of the muscle may disrpuyp the regeneration NMJ and delay reinervation
• increased treatment time and financial costs
• may not really impact degree of atrophy/firbosis

Question 8

At best what can electrical stimulation do for denervated muscles

Answer 8

delay and diminish changes associated with denervation, but it cannot prevent the changes from occurin

Question 9

what is the optimal pulse duration for stimulating a denervated muscle

Answer 9

equal or greater than chronaxie of the denervated muscle (at least 1 millisecond)

Question 10

what is the optimal wave form for stimulating a denervated muscle

Answer 10

DC, interrupted DC, AC low freq

Question 11

what is the optimal frequency for stimulating a denervated muscle

Answer 11

16-25 cycles per second

Question 12

what is the optimal treatment time for stimulating a denervated muscle

Answer 12

need to perform several times daily, for 10 20 seconds isometric contractions each lasting 1-2 seconds

Question 13

what is the optimal on/off time for stimulating a denervated muscle

Answer 13

off time 4-5 times greater than the on time

Question 14

what is the optimal pad placement for stimulating a denervated muscle

Answer 14

large electrodes over the muscle belly

Question 15

what are some of the research findings supporting estim as a treatment for denervated muscles

Answer 15

• Atrophy (measured by weight of muscle) can be retarded by e stim
• The earlier the e stim treatments were started after denervation the better outcome
• Treated muscles were preserved better in superficial than deeper areas
• Rate of reinnervation was neither hastened nor retarded by the treatment

Question 16

what are some possible harmful effects that were found in research studies about using Estim for denervated mauslce

Answer 16

• increased type I atrophy
• Disruption of NMJ
• Supression of nerve reinnervation

Question 17

when does estim work best for denervated muscles

Answer 17

if started early after injury for superficial muslces like those in the face and hand. Large or deep muscles are more problematic because it is difficult to get all the muscle fibers to contract