Finals: Electrotherapy for MM stimulation Flashcards
A condition where the innervation of a muscle is compromised due to factors such as trauma, compression, demyelination, ischemia, or destruction/degeneration.
Muscle Denervation
It often occurs as part of lower motor neuron lesions and affects specific muscle groups, including the supraspinatus, deltoids, triceps, wrist extensors, quadriceps, and dorsiflexors.
Muscle Denervation
Characterized by a temporary conduction block due to mild compression of the nerve.
There is no axonal damage, and wallerian degeneration does not occur.
Recovery typically occurs within a few days to weeks or months, and the prognosis is generally good.
Neuropraxia
Involves the total interruption of axons with preserved connective tissue sheath.
Axonal damage and wallerian degeneration occur, affecting axons from the point of injury up to the terminal end.
While nerve covering remains intact, recovery is facilitated by a rate of nerve growth of approximately 1-2 mm per day, leading to a generally good prognosis.
Axonotmesis
Represents the most severe form of denervation injury, characterized by complete disruption of axons and all supporting structures
Neurotmesis
*Wallerian degeneration occurs, and the prognosis is poor due to the discontinuity of the neural tube. Surgical intervention may be required, and the outcome is guarded, with the potential for aberrant degeneration and neuroma formation.
involves intact nerves with nerve compression. It is equivalent to neuropraxia, characterized by a temporary conduction block without axonal damage. These injuries are the easiest to heal, and recovery typically occurs within a short period.
First Degree Injury
corresponds to axonotmesis. It entails damaged axons with wallerian degeneration while preserving the integrity of the nerve structures. Recovery is facilitated by a rate of nerve growth, leading to a generally good prognosis.
Second Degree Injury
disrupts axons and endoneurium. The injury becomes apparent as the damage extends beyond the nerve itself. Recovery may occur with appropriate management, although it may not be as favorable as in lower-degree injuries.
Third Degree Injury
damages both perineurium and endoneurium while preserving the outermost nerve layer. This injury results in more extensive nerve damage, affecting multiple layers of nerve structures.
Fourth Degree Injury
involves damage to all nerve structures, making it the most severe form of denervation injury. Recovery is challenging, and the prognosis is guarded due to the extensive disruption of nerve tissue.
Fifth Degree Injury
T or F
Partial depolarization of sarcolemma makes muscles difficult to stimulate.
TRUE
Spontaneous contractions due to hypersensitivity to acetylcholine.
Fibrillations
T or F
In denervated mm there is a Decreased resting membrane potential and increased transmembrane resistance.
TRUE
Nerve growth occurs at a rate of ? mm/day, often through collateral sprouting.
Nerve growth occurs at a rate of 1-2 mm/day, often through collateral sprouting.
Stimulation Parameters
Pulse Duration: Typically 300 us for denervated muscles.
Frequency: Often set at 1 Hz.
Amplitude: Visible contraction with low amplitude to prevent burns.
Treatment Time: Usually 30 minutes per session.
Consequences of Interrupted Peripheral Neural Arch
Loss of voluntary activity
Flaccid paralysis
Loss of reflex response (areflexia)
Progressive muscle atrophy
Changes in Denervated Muscle before Re-innervation
Paralysis and wasting
Fibrillation
Marked hypersensitivity to Ach
Atrophy, particularly type 2 fibers
Fibrosis leading to pseudohypertrophy
Goal: Maintain muscle integrity
Electrical muscle stimulation parameters
Effects: Delayed atrophy, increased rate of re-innervation
Stimulation of Denervated Muscles
Results of Electrical Muscle Stimulation
Increased strength, endurance, and quality of motor recruitment
Muscle strengthening through hypertrophy and improved motor recruitment
Gradual motor recruitment and rate of motor unit activation asynchronous recruitment of motor units producing smooth, gradually increase in force
Slow-twitch type i muscle fibers
PHYSIOLOGICAL CONTRACTION
Motor units simultaneously when the stimulus reaches motor threshold producing generally rapid or jerky
Fype 2 muscles, fast-twitched, then type 1
Atrophy muscle type 2
ELECTRICAL-STIMULATION
Aim of FES Treatment
Goal: Enhance or produce functional movement
Target: Grade +2 to +3 functional tasks
Clinical Efficacy of FES
Strengthening in non-neurological conditions
Strength gains similar to voluntary programs, recruiting type II phasic muscle fibers
Contraindications for FES
Cardiac pacemaker or ICD
Carotid sinus placement
Areas with thrombosis or thrombophlebitis
Pregnancy over or around abdomen or low back
