Pain and TENS Flashcards
Peripheral sensitization
Damage to high-threshold nociceptors leads to hypersensitivity
Areas adjacent to those of actual injury hurt as if injured
Tissues respond to stimuli that ordinarily do not produce pain such as touch, clothing, or a hairbrush as if they are painful (allodynia)
Central sensitization
Increased sensitivity to painful stimuli cause increased response amplitude, duration, and feelings of chronic pain
Radiating pain
Originates from an irritated nerve root and travels along nerve’s dermatome
Referred pain
Pain perceived in area with little relation to actual trauma
Projects outward from torso and distally along extremities
Neuropathic pain
Injury or irritation to sensory or motor nerves cause pain that persists unrelated to injruy
Transcutaneous electric nerve stimulation
Modifies pain perception by decreasing conductivity and transmission of noxious impulses from pain fibers
Delivers pulsatile current through skin for pain relief by stimulating the opioid system
Decreases pain perception by decreasing conductivity and transmission of noxious impulses from small pain fibers
Electrode placement
Most units have four electrodes
Place electrodes over or around painful site
can also be placed over motor points, trigger points, or acupuncture points
Can be placed parallel to painful site, on each side of scar or surgical incision, crossed at the site of pain, bracketed, or linear
Initial placement should be changed if outcome is less than expected or if the patient is experiencing pain or discomfort
Sensory nerve stimulation from TENS
Receive a greater amount of stimulation
Can override pain receptors by masking pain
High-frequency, short-duration, sensory-level currents activate the gate control theory
Motor nerve stimulation from TENS
Acupuncture like motor stimulation that reduces pain due to endorphin theory
When can TENS be applied
During procedure or exercise
Post exercise or procedure
At home for pain control
Chronic pain
What type of current is TENS?
Alternating current
What affects TENS outcomes
Diameter of nerve
Depth of nerve
Duration of pulse
Caffeine level
Pain-spasm cycle
Pain causes muscle spasm/trigger points, which cause ischemia, which cause dysfunction due to decreased oxygen/nutrition, which causes pain
Types of TENS
Subsensory level
Sensory level
- High frequency
- Brief or intense TENs
- Burst TENS
- Modulation TENS
Motor level
Noxious level
Combination/alternate forms
- Burst mode or pulse trains TENS
Subsensory level TENS (Microcurrent electrical stimulation (MENS) or sublimination stimulation)
Monophasic pulsed current intensity below threshold for nerve depolarization
Stimulation enhances cellular physiology and processes by moving ions in tissues at a low magnitude
Cutaneous sensation is not felt
Uses acupuncture points
Studies failed to demonstrate treatment is significantly more effective than placebo
Cranial electrotherapy stimulation
Type of subsensory level TENS
Treats sleep disorders, depression, anxiety
Sensory level TENS (conventional or high rate TENS)
Activates cutaneous tactile sensory fibers resulting in cutaneous paresthesia or tingling without eliciting a motor response
Uses gate control mechanism and opiate-mediated pain control theory to decrease pain
Frequency is from 50-100 Hz
Amplitude is increased until patient feels tingling or buzzing at a comfortable level
Long term effects are limited to no longer than one hour
Types
- High frequency TENS
- Brief or intense TENS
- Burst TENS
- Modulation TENS
Motor level (strong low-rate TENS or acupuncture-like TENS)
High amplitude and low frequency
Pulse width: 150-200 microseconds
Frequency: 2-10 Hz
Amplitude: high enough to produce visible muscle contractions (usually 30-60 milliamps)
Time: 30-45 minutes
Purpose: Uses Gate control theory or opiate mediated pain control to treat chronic injuries
Goals is to selectively activate small diameter nerve fibers arising from muscles to induct a phasic muscle twitch
Avoid any joint movement contraindicated
Use for chronic pain, pain caused by damage to deep tissues, myofascial pain, and pain caused by muscle spasm
Noxious level TENS (Electro-acupuncture, hyperstimulation, or noxious-level TENS)
Pulse width: 1 ms - 1 second
Frequency: greater than 100 Hertz (pps)
Amplitude: increased until pain is perceived
Time: 30 seconds each point
Purpose: Uses opiate mediate pain theory for preparation for procedures/debridement
Effects are short-lived and transitory
Burst mode or pulse trains TENS
Provides both high and low rate TENS characteristics
Easily tolerated by patients
Long lasting effects
Interferential current
Two leads are generated on separate channel and the other a variable sine wave
Channels combine/interface to produce a frequency of 1-100 Hz
Interferential current therapy
High frequency carrier waveform penetrates the skin more deeply than a regular TENS unit with less discomfort
Deeper tissues cancel out the carrier waveform resulting in TENS like signal deeper under the skin
Effects of interferential current therapy
Sensory nerve stimulation
- Pain reduction due to receiving a lower amplitude stimulation
- More comfortable than conventional methods
Interferential current parameters
Uses discrete electrical pulses
Pulse duration: 80-200 microseconds
Frequency: 4000-4100 Hz
Amplitude: Increased to create deep analgesia and a comfortable soothing stimulation
Duration: 10-30 minutes applied 3x a week
Purpose: Utilizes gate control theory of pain relief to decrease pain, allow for muscle stimulation, increase blood flow, and control edema
Intensity should not be increased during treatment after initial comfort level is established
