E-stim For Pain Management

Question 1

describe how pain is a multidimensional phenomenon

Answer 1

• the sensitivity of the particular tissue involved
• the persons mental state
• the attitudes of the culture toward pain
• the person’s previous experience of pain
• pain is the body’s for actual or potential injury

Question 2

How is pain assessed

Answer 2

• Visual/numerical scales
• adult vs pediatric scales
• verbal and non-verbal (ex: pain assessment in advances Dementia scale - PAINAD)
• pain questionnaires

Question 3

Primary afferent neurons and what they do?

Answer 3

• A-beta fibers: large myelinated axons with discriminative touch
• A-delta fibers: smaller than A-beta fibers, myelinated (sharp pain)
• C-fibers: small, unmyelinated nerve fibers (dull and throbbing pain)

Question 4

Primary efferent neurons and what they do

Answer 4

• Large and myleninated: slow twitch type 1 fibers usually smaller than fast-twitch type 2 fibers

Question 5

What are the 2 theories of pain relief

Answer 5

• gate control theory
• endogenous opioid theory

Question 6

Gate control theory

Answer 6

• utilizes conventional or high rate/low width electrical stim
• Though to control pain by stimulating non-nociceptive sensory nerves
• large diameter, low threshold nerves like A-beta’s
• A-beta “beats” the other pain sensations to the brain and interacts with the CNS to inhibit transmission along A-delta and C-fibers

Question 7

Endogenous opioid theory

Answer 7

• utilizes acupuncture like or low rate high width electrical stimulation
• the body releases it’s own pain modulating substances (endorphins)
• endorphins are released with stimulation of A-delta and C-fibers
• stimulating of these can inhibit pain transmission
• bearable levels of pain noxious stimulation have been shown to reduce the intensity of less bearable pre-existing pain

Question 8

Conventional stimulation

Answer 8

• high rate low width
• use gate controlled theory

Question 9

Acupuncture

Answer 9

• low rate high width
• endogenous endorphin theory

Question 10

Modulation

Answer 10

• variation in variable such as rate/width or both to decrease accommodation/adaption

Question 11

Burst Mode

(pain mangement)

Answer 11

• often an option preset in a stim machine
• a series of pulses interrupted by interpulse interval

Question 12

Conventional/high rate stim features

Answer 12

• high frequency: 100-150 pps
• short duration (width) pulse - 50-80 microseconds
• amplitude to produce comfortable tingling sensation without contraction
• based on gate controlled theory
• only effective while stimulation is applied
• this may allow for interruption in the pain-spasm-pain cycle
• may be used as needed up to 24 hr/day (doesn’t last when the stim is removed)
• may use modulation to decrease accommodation
• activate A-betas

Question 13

Acupuncture like/low rate

Answer 13

• low pulse frequency: <10 pps
• long pulse duration: >200 microseconds (needed for contraction)
• amplitude to produce small muscle contraction/twitch (uncomfortable to stimulate A-delta to release endorphins)
• based on endogenous opioid theory
• effective for 4-5 hours after stimulation ends
• treatment no longer than 45 minutes to avoid DOMS (usually 20-30 minute sessions)
• may use modulation to decrease accommodation
• generally low rate, high duration to stimulate motor nerve or A-delta’s

Question 14

How to place electrodes

Answer 14

• most common is surrounding the painful area
• over trigger points or acupuncture points
• proximal to the site of pain along the pathway of the sensory nerves
• along or within a dermatome
• 1-2 Channels/2-4 electrodes

Question 15

Common waveforms for pain management

Answer 15

• pulsed biphasic
• pre-modulated (AC)
• interferential current (AC)

Question 16

pulsed bi-phasic

Answer 16

• can do conventional and acupuncture-like with this current
• similar to the waveform in the small TENS unit
• balanced charge

Question 17

pre-modulated

Answer 17

• typically used for conventional e-stim
• AC current alone would lead to rapid accommodation
• current is an AC current that is modulated within the unit to vary in amplitude in order to decrease accommodation
• an alternating current with sequentially increasing and decreases amplitude
• can use 2-4 electrodes

Question 18

interferential current

Answer 18

• typically used for conventional e-stim
• created by the intersection of 2 AC currents within the body
• requires 4 electrodes
• the two currents have slightly different frequencies
• the intersection of the current creates a larger amplitude current to deeper tissues at greater comfort (low back/larger areas)

Question 19

Beats

Answer 19

• the pulses created by the intersection in interferential current
• the beat frequency is the difference in the frequency between the two sine waves
• This is the treatment current

Question 20

Sweep

Answer 20

• refers to the frequency modulation of IFC current (can be added to treatment

Question 21

Scan

Answer 21

• refers to the amplitude modulation of the IFC current
• this changes the effective field of stimulation causing the patient to feel the stimulation in a moving field