T E N S Trancutaneous Electrical Nerve Stimulation

T. E. N. S. Trancutaneous Electrical Nerve Stimulation

General Concepts: • An Approach to pain control – Trancutaneous Electrical Nerve Stimulation: – Any stimulation in which a current is applied across the skin to stimulate nerves – 1965 Gate Control Theory created a great popularity of TENS – TENS has 50 -80% efficacy rate – TENS stimulates afferent sensory fibers to elicit production of neurohumneral substances such as endorphins, enkephalins and serotonin (i. e. gate theory)

TENS • Indications – Control Chronic Pain – Management postsurgical pain – Reduction of posttraumatic & acute pain • Precautions – Can mask underlying pain – Burns or skin irritation – prolonged use may result in muscle spasm/soreness – caffeine intake may reduce effectiveness – Narcotics decrease effectiveness

TENS may be: • • • high voltage interferential acuscope low voltage AC stimulator classical portable TENS unit

Biophysical Effects • Primary use is to control pain through Gate Control Theory • May produce muscle contractions • Various methods – High TENS (Activate A-delta fibers) – Low TENS (release of -endorphins from pituitary) – Brief-Intense TENS (noxious stimulation to active C fibers)

Techniques of TENS application: • • • Conventional or High Frequency Acupuncture or Low Frequency Brief Intense Burst Mode Modulated

Protocol for Various Methods of TENS

Conventional Tens/High Frequency TENS • Paresthesia is created without motor response • A Beta filers are stimulated to SG enkephlin interneuron (pure gate theory) • Creates the fastest relief of all techniques • Applied 30 minutes to 24 hours • relief is short lives (45 sec 1/2 life) • May stop the pain-spasms cycle

Application of High TENS • Pulse rate: high 75 -100 Hz (generally 80), constant • Pulse width: narrow, less than 300 m. Sec generally 60 micro. Sec • Intensity: comfortable to tolerance

Set up: • 2 to 4 electrodes, often will be placed on post-op. Readjust parameters after response has been established. Turn on the intensity to a strong stimulation. Increase the pulse width and ask if the stimulation is getting wider (if deeper=good, if stronger. . . use shorter width)

Low Frequency/Acupuncture-like TENS: • Level III pain relief, A delta fibers get Beta endorphins • Longer lasting pain relief but slower to start • Application – pulse rate low 1 -5 ppx (below 10) – Pulse width: 200 -300 micro. Sec – Intensity: strong you want rhythmical contractions within the patient’s tolerance

Burst Mode TENS – Carrier frequency is at a certain rate with a built in duty cycle – Similar to low frequency TENS – Carrier frequency of 70 -100 Hz packaged in bursts of about 7 bursts per second – Pulses within burst can vary – Burst frequency is 1 -5 bursts per second – Strong contraction at lower frequencies – Combines efficacy of low rate TENS with the comfort of conventional TENS

Burst Mode TENS - Application • Pulse width: high 100 -200 micro. Sec • Pulse rate: 70 -100 pps modulated to 1 -5 burst/sec • Intensity: strong but comfortable • treatment length: 20 -60 minutes

Brief, Intense TENS: hyperstimulation analgesia – Stimulates C fibers for level II pain control (PAG etc. ) – Similar to high frequency TENS – Highest rate (100 Hz), 200 m. Sec pulse width intensity to a very strong but tolerable level – Treatment time is only 15 minutes, if no relief then treat again after 2 -3 minutes – Mono or biphasic current give a “bee sting” sensation – Utilize motor, trigger or acupuncture points.

Brief Intense TENS - Application • • Pulse width: as high as possible Pulse rate: depends on the type of stimulator Intensity: as high as tolerated Duration: 15 minutes with conventional TENS unit. Locus stimulator is advocated for this treatment type, treatment time is 30 seconds per point.

Locus point stimulator • Locus (point) stimulators treatment occurs once per day generally 8 points per session – Auricular points are often utilized • Treat distal to proximal • Allow three treatment trails before efficacy is determined • Use first then try other modalities

Modulated Stimulation: • Keeps tissues reactive so no accommodation occurs • Simultaneous modulation of amplitude and pulse width • As amplitude is decreased, pulse width is automatically increased to deliver more consistent energy per pulse • Rate can also be modulated

Electrode Placement: • May be over the painful sites, dermatomes, myotomes, trigger points, acupuncture points or spinal nerve roots. • May be crossed or uncrossed (horizontal or vertical

Contraindications: • • • Demand pacemakers over carotid sinuses Pregnancy Cerebral vascular disorders (stroke patients) Over the chest if patient has any cardiac condition