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1. TENS

2. Definition
Sreeraj S R
 Transcutaneous Electrical Nerve Stimulation (TENS) is a
method of electrical stimulation which primarily aims to
provide a degree of pain relief (symptomatic) by
specifically exciting sensory nerves and thereby
stimulating either the pain gate mechanism and/or the
opioid system.

3. Mechanism of Action
Sreeraj S R
 Possible Pain-Relieving Mechanisms;
 Activation of ‘pain-gating’ mechanisms.
 Removal of the substances which stimulate pain nerve
endings from within the damaged area

4. Parameters used for TENS
Sreeraj S R
 Waveforms
 Frequency or Rate
 Pulse width or Duration
 Amplitude or Intensity

5. Sreeraj S R
Wave forms
irritating as
sine wave
 Square / rectangular
 Instantaneous rise
 Less skin
approaches
form
 For nerve
associated
pathology
damage
with pain
 For hypersensitive and
chronic pain patients
 Delayed, long-lasting
analgesia
Triangular / spike
 Rapidly rising, but not
instantaneous
skin irritating
 More
therefore requires
frequent movement of
electrodes or shorter
treatment times to avoid
skin irritation
 For acute pain or resistant
tissue
 Immediate, short lasting
pain relief
4/4/2020

6. Frequency or Rate
Sreeraj S R
 High Frequency (80-120):
 Large myelinated fibers respond effective > 100Hz
 Immediate relief of pain
 Acute pain
 Low Frequency (1-20):
 Small unmyelinated fibers respond effectively at <100Hz
 Increase endorphin production, thus analgesia following stimulation
 Chronic pain

7. Pulse width or Duration
Sreeraj S R
Pulse width Indications
50μs Large myelinated fibers (sensory
touch)
100 - 150μs Normal neuromuscular system
200 μs Small myelinated fibers
200 – 300 μs Patients with neurological damage

8. Amplitude or Intensity
Sreeraj S R
 TENS units intensity ranges form 1 mA to 100 mA
 TENS is only effective when the patient actually feels
the stimulus
 Patients need to increase the intensity when the body
accommodates to the stimulus (when they don’t feel the
stimulation anymore)
 Dying batteries can cause fading intensities

9. Types of TENS
Sreeraj S R
 Conventional TENS or High Frequency TENS
 Acupuncture-like TENS (AL-TENS) or Low Frequency TENS
 Brief TENS or Intense TENS
 Burst TENS
 Modulated TENS or Modified TENS

10. Conventional or High TENS
Sreeraj S R
 Frequency – 50 Hz to 100 Hz
 Pulse Width – 20 μs to 60 μs
 Intensity – (0 mA to 30 mA).
 The intensity until a prickling or tingling sensation is felt.
 Principle –Presynaptic inhibition by pain gate
mechanism by stimulating Aα and Aβ fibres.
 Duration – 30 to 60 minutes once or twice daily.

11. Acupuncture or Low TENS
Sreeraj S R
 Frequency – 1 Hz to 4 Hz
 Pulse Width – 150 μs to 250 μs
 Intensity – 30 mA to 60 mA.
 applied to acupuncture points or motor points of muscle in the
segmentally related myotome.
 Principle –This stimulates the high threshold Aδ and C fibres,
which lead to release of endogenous opioids and provides further
sensory input from muscle spindle afferents (chemical theory).
 Duration – 20 to 30 minutes once a day.

12. Burst TENS
Sreeraj S R
 Burst TENS is a series of pulses (i.e. a train), repeated 1-
5 times a second, commonly twice.
 Each train or burst consists of a number of individual
pulses at the usual conventional TENS frequencies of 50
Hz to 100 Hz but at higher intensity.
 It combines both the conventional and acupuncture-like
TENS and
 therefore provides pain relief by both routes.

13. Brief or Intense TENS
Sreeraj S R
 Frequency – More than 100 Hz
 Pulse Width – 150 μs to 250 μs
 Intensity – Highest level tolerated by the patient.
 Principle –Activity in cutaneous Aδ afferents induced by
intense TENS produce peripheral blockade of nociceptive
afferent activity (Central biasing mechanism).
 Duration – 30 to 60 minutes once or twice daily.

14. Modulated or Modified TENS
Sreeraj S R
 In modulated TENS the pulse length, frequency, and
amplitudes can be constantly and automatically varied.
 This cyclical variation is believed to prevent adaptation of
the nerves to the current (no accommodation)
 is particularly appropriate as a variant of conventional
TENS used over long periods.

15. Electrode Placement
Sreeraj S R

16. The position of electrodes and electrical characteristics of TENS
when used to manage labour pain
Sreeraj S R
Electrode Placement

17. Sreeraj S R
4/4/2020
Electrode Placement

18. USES OF TENS
Osteoarthritis (disease of the joints).
Fibromyalgia (aching and pain in muscles, tendons, and joints all over the
body, especially along the spine.
Tendinitis (an inflammation or irritation of a tendon).
Bursitis (inflammation of the fluid-filled sacs that cushion joints)
Labor pain.
Low back pain.
Chronic pelvic pain.
Diabetes-related neuropathy (damage to the nerves that connect the brain
and spinal cord to the rest of the body).
Peripheral artery disease (“hardening of the arteries” that circulate blood to
the body).

19. Contraindication
Sreeraj S R
 a pacemaker
 undiagnosed pain.
 heart condition
 On head or neck of someone with epilepsy
 Someone with venous or arterial thrombosis or thrombophlebitis
 Someone with indwelling phrenic nerve or urinary bladder
stimulators

20. Contraindication
Sreeraj S R
 Around the head
 On the eyes
 Over mucosal surfaces
 Using electrodes on infected skin
 Electrodes across the chest of a patient with cardiac disease
 Electrodes should not be placed near carotid artery in the
anterolateral region of the neck. There is a potential risk that
stimulation at this site might cause heart block by exciting the
vagus nerve.

21. Precautions
Sreeraj S R
 Areas of skin irritation, damage or lesions
 Areas with impaired sensation
 Over abdominal, lumbosacral or pelvic regions during pregnancy
other than for labor/delivery
 Tissues vulnerable to hemorrhage or hematoma
 Athletes should not be permitted to participate in sports while
under the influence of TENS analgesia
 Extreme caution is needed with patients taking narcotic
medication or who are known to have hyposensitive areas.

22. Precautions
Sreeraj S R
 Incompetent patients may not be able to manage the device and it
must be kept out of reach of children.
 For patients with diagnosed malignancies that have been
diagnosed as terminal, TENS can be used for pain control with
informed consent of the patient.
 Otherwise, TENS should not be used when malignancies are
present.

23. THANK YOU
Sreeraj S R