TENS.pptx

TENS Modality

1. TENS Dr. Anvita Telang (PT) Assistant Professor (Musculoskeletal sciences)

2. Transcutaneous nerve stimulation- simple, non invasive analgesic technique used in healthcare by physiotherapists Transcutaneous electrical nerve stimulation (tens) is the application of low frequency current in the form of pulsed rectangular currents through surface electrodes on the patient’s skin to reduce pain. Pulse shape: rectangular Pulse width: microseconds (100 microsec to 200 microsec) Frequency: 2 Hz – 600 Hz Intensity: 0-60 miliamps (mA)

3. Uses of TENS Analgesic effects: (acute pain) Chronic pain Postoperative pain Low back pain Labour pain Arthritis Dysmenorrhoea Phantom limb pain Musculoskeletal pain Trigeminal neuralgia Bone fracture Peripheral nerve injuries Metastatic bone pain

4. Non analgesic effects of TENS Antiemetic effects Improving blood flow Nausea, morning sickness, travel sickness Diabetic neuropathy Nausea associated with chemotherapy Healing of wounds and ulcers

5. FOUR CHANNEL TENS TWO CHANNEL TENS

6. TENS FOR WOUND HEALING TENS FOR LABOUR PAIN

7. History of TENS Egyptians used to treat arthritis pain by using some electrogenic fish. This increased the popularity of using electricity in medicine (2500 BC). Melzac and wall (1965) provided a physiological rationale for electroanalgesia effects and proposed the pain gate mechanism theory.

8. What is pain Pain is an unpleasant disturbed sensation, which accompanies the activation of nociceptors. Pain is a subjective phenomenon with multiple dimension. Nociceptors are the sensory receptors, which carries pain stimulus. Any physical, chemical, thermal or mechanical stimulus like heat, cold or pressure activates these nociceptors. These are free nerve endings found in all body tissues. They carry pain stimulus to the higher centers. A Delta fibers: Fast conducting large diameter myelinated fibers, which conducts with a velocity of 5–30 m/s. C-fibers: Slow conducting small diameter nonmyelinated fibers, which conducts with a velocity of 2–5 m/s.

9. Fast pain is transmitted over the larger, faster-conducting A-delta afferent neurons and originates from receptors located in the skin. Slow pain is transmitted by the C afferent neurons and originates from both superficial (skin) and deeper (ligaments and muscle) tissue.

10. Painful stimuli activates nociceptors (A delta and C) transmitted to spinal cord in the substansia gelatinosa (via dorsal route) transmitted to higher parts of the spinal cord and to the thalamus (located in the cortex) via the spinothalamic tract. Pain afferents send branches to the periaqueductal grey region in the mid brain and activates the descending pathway from there the impulses travel to the dorsal horn of spinal cord, impulses are blocked or inhibited.

11. Pain gate mechanism Pain gate control: The pain gate theory was first postulated by Ron Melzack and Pat Wall in 1965. The Gate Control Theory of Pain is a mechanism, in the  spinal cord ( substansia gelatinosa ) , in which pain signals can be sent up to the  brain  to be processed to accentuate the possible perceived pain, or attenuate it at the spinal cord itself. 

12. The 'gate' is the mechanism where pain signals can be let through or restricted. One of two things can happen, the gate can be 'open' or the gate can be 'closed':  If the gate is open, pain signals can pass through and will be sent to the brain to perceive the pain.  If the gate is closed, pain signals will be restricted from travelling up to the brain, and the sensation of pain won't be perceived. 

13. Types of TENS Conventional TENS or High TENS Acupuncture TENS or Low TENS Brief Intense TENS Burst TENS Modulated TENS

14. Physical principles Large diameter fibres such as A beta and A alpha have low threshold of activation to electrical stimuli when compared with small diameter fibre (A delta and C) TENS works on the principle of pain gate mechanism. Where A beta fibres are selectively stimulated without activating small diameter nociceptive fibres (A delta and C) This type of TENS is the conventional type of TENS (low intensity and high frequency) Skin offers high resistance at this pulse frequency therefore, such a current will stimulate superficial cutaneous nerve fibres rather than deep seated visceral and muscle fibres. TENS is applied to the patient using surface electrodes on the skin (cathode is black, anode is red)

15. Conventional TENS Aim of conventional TENS is to activate selectively A beta fibres without activating small diameter A Delta and C fibres Conventional TENS segmental analgesia which is localised to the dermatome Produces strong comfortable and non painful paraesthesia (tingling sensations) Pattern is usually continuous

16. Acupuncture like TENS (AL-TENS) This type of TENS should be defined as the induction of forceful but non-painful phasic muscle contraction at myotomes related to the origin of the pain The purpose of this type of TENS is to selectively activate small diameter fibres (A delta) by induction of phasic muscle twitches TENS is delivered over the motor points Patients report slight discomfort when these low frequency pulses are used to generate muscle twitches Extra segmental analgesia in the same manner as acupuncture Elevates plasma beta endorphins levels and causes analgesia

17. Brief intense TENS The aim of this type of TENS is to activate small diameter A delta fibres by delivering TENS over the peripheral nerves arising at the site of the pain at an intensity tolerable to the patient. TENS is delivered over the site of pain using high frequency and high intensity currents which are tolerable to the patient. It is used as a counter irritant and can be delivered only for a short duration of time Mechanism of action – peripheral blockade of nociceptive afferent activity, segmental and extra segmental analgesia

18. Conventional TENS High TENS or conventional TENS High frequency low intensity Tingling pins and needles sensation Presynaptic inhibition of transmission of nociceptive A delta and C fibres in substansia gelatinosa Used in acute pain and superficial pain Frequency : 100-150 Hz Pulse width : 100-500 microseconds Intensity : 12-30 mA

19. Acupuncture TENS High intensity and low frequency Stimulation of A delta and C fibers Release of endogenous opiods ( enkephalins and beta endorphins) Used in chronic and deep pain Frequency : 1-5 Hz Pulse width : 100-150 microseconds Intensity : 300 mA

20. Burst tens Called as wave train Series of pulses repeated 1-5 times per second Each burst consists of individual pulses like high or conventional TENS Used for pain relief Frequency: 50-150 Hz

21. Brief TENS Long duration 0.2 ms Used for local pain relief Should be used for not more than 15 mins Frequency : 100 Hz Intensity : 20-50 mA

22. Modulated TENS Modulation in pulse length frequency and amplitude To improve patient tolerance To prevent accommodation

23. Indications Chronic pain syndrome Phantom limb pain Reflex sympathetic dystrophy Postoperative pain Obstetric pain.

24. Contraindications 1. Continuous application of high TENS may result in some electrolytic reaction below the skin surface 2. TENS is contraindicated in patients having cardiac pacemakers may be because of possible interference with the frequency of pacemaker 3. TENS should be avoided in first three months of pregnancy. 4. TENS should be avoided in hemorrhagic conditions. 5.TENS should be avoided over open wounds, carotid sinus, over the mouth, near eyes, etc

25. Methods of Treatment Electrode placement TENS electrode can be placed over: Area of greater intensity of pain 2. Appropriate peripheral nerve 3. To the appropriate dermatome or spinal nerve 4. To the acupuncture, motor or trigger points

26. Thank you !