TENS Nerve Stimulation PDF

TRANSCUTANEOUS ELECTRICAL RAFIA RAFIQ BSPT, ADPT, MS(C.P), NERVE STIMULATION MBA* Assistant Professor JCRS  OBJECTIVES OF SESSION 1. Introduction 2. Feature of Tens 3. Theory of Tens 4. Appli...

TRANSCUTANEOUS ELECTRICAL RAFIA RAFIQ BSPT, ADPT, MS(C.P), NERVE STIMULATION MBA* Assistant Professor JCRS  OBJECTIVES OF SESSION 1. Introduction 2. Feature of Tens 3. Theory of Tens 4. Application of Tens 5. Uses of Tens 6.Electrode placement 7.Precautions and Contraindications. INTRODUCTION  It’s the electrotherapeutic modality used for nerve stimulation.  Transcutaneous = Through skin  Nerve stimulation= current have sufficient intensity to depolarize sensory, motor and pain nerves.  Deliver Electricity across the intact surface of the skin to activate the underlying nerves. Simple , non invasive analgesic modality.  ITS MORE ACCURATE TO DESCRIBE TENSE AS A PULSED CURRENT. TRANSCUTANEOUS ELECTRICAL NERVE STIMULATION. Electrical stimulators, capable of delivering pulsed currents, for stimulating (depolarizing) peripheral nerve fibers through the skin. In this chapter, TENS is defined as the application of pulsed electrical current for inducing electro analgesia.  TRANSCUTANOUS ELECTRICAL NERVE STIMULATION (T.E.N.S) It is low frequency electrical current used to stimulate peripheral nerve using skin surface electrode and it is aim to relief pain(acute or chronic) It is non-invasive ,non pharmacological physical therapy modalities used to relief through stimulation of peripheral nerve using surface electrode. RATIONALE FOR USE Pain is the dominating symptom that prompts people to consult health- care practitioners. The medical approach to pain therapy is to offer drugs and, if drugs are not successful, to consider surgery. TENS therapy is an attractive therapeutic alternative for managing pain (Berman et al., 2000) because it is noninvasive and has no side effects. TENS therapy can be administered easily at home and at work, which makes it even more attractive. Finally, the lower cost associated with the delivery of TENS, compared with the high cost of drugs and surgery, makes this treatment more affordable to patients BIOPHYSICAL CHARACTERISTICS, 1.Waveforms (Biphasic , symmetrical , asymmetrical) 2.Pulses ( single pulse/burst of pulses) 3.Frequency (1-200Hz) 4.Pulse width or duration (50-400microsec) 5.Amplitude or intensity (0-120mA) THERAPEUTIC EFFECTS AND INDICATIONS 1. Pain Modulation. The sole therapeutic effect of TENS, is to modulate or decrease pain through the process of peripheral nerve depolarization by using pulsed electrical current. There is a substantial body of evidence to suggest that the selective, or preferential, depolarization of specific groups of afferent nerve fibers affects two key pain modulation systems, known as the gate and opiate systems. PRINCIPALS OF NERVE FIBER ACTIVATION Initially activation of non-nociceptive nerve fibers like A-alpha , A-beta fibers which have low threshold of stimulation and causing tingling. Followed by the activation of A-delta and C fibers causing pain. GATE CONTROL THEORY Gate control theory was described by Malzack and Wall in 1995. This theory explain about the pain modulating system in which a neural gate present in the spinal cord can open and close the thereby modulating the perception of pain. The gate control theory suggest that Psychological factors play a role in the perception of pain. This theory states that stimulation of nerves carrying non-painful sensations (called A-beta nerve fibers) closes a neurological “gate” in the spinal cord that reduces transmission from pain nerves (called A-delta and C nerve fibers) to the brain. By preventing pain signals from reaching the brain, the perception of pain decreases. NOXIOUS-LEVEL STIMULATION Noxious stimulation induces peripheral afferents responsible for transducing pain (including A-delta and C- nerve fibers, as well as free nerve endings) throughout the nervous system of an organism. Combinations of higher current amplitudes (S) and longer pulse durations (D), will lead to the depolarization of all three nerve fibers—namely, sensory (A-beta), motor (alpha), and nociceptive (A-delta and C fibers). This level of stimulation can be clinically confirmed when the patient experiences a strong and mixed sensation of muscle contraction and pain during stimulation. In other words, this level of stimulation is present when a muscle contraction is clearly apparent and when the patient describes the electrically evoked sensation as being just below the threshold of being intolerable, or too painful. Dorsal horn is responsible for the passing on information which can be interpreted as pain. The DRG is a group of cell bodies responsible for the transmission of sensory messages from receptors such as thermoreceptors, nociceptors, proprioceptors, and chemoreceptors, to the CNS for a response. This area is referred as the gate as its prevents the brain from receiving too much information too quickly.  DOSIMETRY Dosimetry associated with the application of TENS is based on the selection of one of the following five modes of delivery: Conventional, Acupuncture like, Brief intense, urst, and modulation. Each mode is characterized by the setting of three electrical parameters (pulse/burst duration, pulse/burst frequency, and current amplitude, all of which translating into four physiologic and therapeutic correlates (preferential fiber depolarization, preferential mechanism behind pain relief, onset of analgesia, and duration of analgesia). PAIN RELIEF Pain can be managed in the short term using analgesics , but long term use can be detrimental to the patient’s health. Side effects of the long use of analgesics may affect on liver, kidney or stomach. In many cases where pain is constant ,a medical practitioner or physiotherapist may recommend the use of a TENS unit. Why TENS? Because it is safe , effective and virtually with no side effects. OPIATE SYSTEM There is a substantial body of evidence (McMahon et al., 2015) to suggest that the human body possesses its own pain modulation system, known as the descending endogenous opiate system (DEOS). This system, at the supraspinal level and involves neurohormonal activity from particular subcortical areas, such as the periaqueductal gray matter and the nucleus raphe magnus. The term descending indicates that this system operates in a descending fashion, from the supraspinal to the spinal levels. The word endogenous opiate indicates that pain modulation occurs through the release of opiate-like substances secreted by the body itself. These endogenous opiate substances are known by the generic term endorphins. CONVENTIONAL MODE This mode involves delivery of electrical pulses with relatively short durations, high frequencies, and current amplitudes corresponding to sensory-level stimulation. It is called conventional because, by convention or clinical experience, clinicians usually select this mode to begin TENS therapy, as it is perceived by most patients as the most comfortable of all modes. This mode implies the preferential depolarization of large-diameter A-beta fibers using current amplitudes and pulse durations within the sensory-level range. Electrical stimulation is perceived as comfortable (pins and needles; tingling; no muscle contraction), and pain modulation occurs through the gate system. The onset of analgesia is relatively rapid, and analgesia itself is ACUPUNCTURE-LIKE MODE This mode refers to the delivery of electrical pulses with relatively long durations, low frequencies, and current amplitudes capable of sensory- and motor-level stimulation. It is described as acupuncture-like because the pulse frequency is low, resembling traditional needle acupuncture therapy, in which the practitioner slowly rotates the needle in the patient’s skin. This mode implies the preferential depolarization of afferent large- diameter A-beta and efferent alpha motor fibers innervating skeletal muscles. Electrical stimulation is perceived as tolerable as well as a mixed sensation of tingling and muscle contraction. Pain is presumed to occur via the opiate system. Onset of analgesia is relatively slow, and analgesia is sustained for a relatively long period BRIEF-INTENSE MODE This mode involves the delivery of electrical pulses with relatively long durations, high frequencies, and current amplitudes capable of noxious stimulation It is described as brief intense because durations of application are briefer and current amplitudes much higher, or more intense, than in the other modes, triggering a some what brief yet intense, and sometimes painful, stimulation during therapy. This mode implies the preferential depolarization of all nerve fibers (A-beta, A- delta, and C fibers),causing a mixed sensation of strong muscle contraction and maximum tolerable pain. Pain modulation occurs through the opiate system. The onset of analgesia is relatively rapid, and analgesia is sustained for a relatively long period. BURST MODE This mode refers to the delivery of bursts of pulses of relatively low burst frequencies, with current amplitudes capable of sensory and motor stimulation. It is described as burst to emphasize the use of bursts of pulses rather than individual pulses. This mode implies the preferential depolarization of sensory A-delta and motor alpha fibers. Electrical stimulation is felt as a mixed sensation of tingling and moderate motor contraction. Pain modulation occurs through the opiate system. The onset of analgesia is relatively slow, and analgesia is sustained for a relatively long period. MODULATION MODE This last mode calls upon the random electronic modulation of pulse duration, pulse frequency, and current amplitude. It is called modulation because one, or two, or all three stimulation parameters are electronically, and randomly, modulated at the same time during therapy. This mode is presumed to decrease brain (sensation) and nerve (depolarization) habituation to electrical input. Because there is a variable modulation (cycles of increasing and decreasing values), variability is expected to occur with regard to the types of fibers preferentially depolarized and the pain modulation present, as well as the onset and duration of analgesia. TECHNIQUES FOR APPLICATION Electrode placement: TENS electrode can be placed over— 1. Area of greater intensity of pain. 2. Superficial nerve proximal to the site of pain. 3. To the appropriate dermatome. 4. To the nerve trunk trigger point. A number of treatment methods may be used depending upon the severity of the problem. 1. TENS can be used for a single daily treatment of 40 minutes duration. 2. Portable TENS can be used continuously for 24 hours. 3. TENS can be used in night, e.g. for the treatment of phantom limb pain TECHNIQUES FOR APPLICATION Depending of the severity of pain. The golden rule is that TENS should be applied until the patient reports satisfactory pain relief. If no pain relief is achieved using a given mode, another mode of stimulation should be used instead of prolonging the application duration of the initial mode. TENS Application Treatment frequency may range between single and multiple applications per day, again depending of the severity of pain. Because there is no side effect associated with the application of TENS, patients may receive multiple daily applications over several weeks and months for the management of their pain conditions OVERVIREW Therapeutic uses Contraindication and danger of TENS Clinical method of application and dosage THERAPEUTIC USES TENS can be used for the treatment of: 1. Chronic pain syndrome 2. Phantom limb pain 3. Reflex sympathetic dystrophy 4. Postoperative pain 5. Obstetric pain. 6.Reduction of oedema RESEARCH BASED INDICATION: As indicated, the strength of evidence is ranked as strong for several conditions, including postoperative abdominal pain, postoperative thoracic pain, osteoarthritis pain, Dysmenorrheal pain postoperative orthopedic pain  RESEARCH BASED INDICATION: low-back pain, Neurogenic pain, chronic pain syndromes, Stump/phantom pain, Rheumatoid arthritis pain chronic pain syndromes Stump/phantom pain and orofacial pain. CONTRAINDICATION. 1. Patients who do not comprehend the physiotherapist’s instructions or who are unable to co-operate 2. It has been widely cited that application of the electrodes over the trunk, abdomen or pelvis during pregnancy is contraindicated BUT a recent review suggests that although not an ideal (first line) treatment option, application of TENS around the trunk during pregnancy can be safely applied, and no detrimental effects have been reported in the literature for publication details). 3. TENS during labour for pain relief is both safe and effective. 4. Patients with a Pacemaker should not be routinely treated with TENS though under carefully controlled conditions it can be safely applied. Patients who have an allergic response to the electrodes, gel or tape 5. Electrode placement over dermatological lesions e.g. dermatitis, eczema 6. Application over the anterior aspect of the neck or carotid sinus[ PRECAUTIONS. 1. If there is abnormal skin sensation, the electrodes should preferably be positioned elsewhere to ensure effective stimulation 2. Electrodes should not be placed over the eyes 3. Patients who have epilepsy should be treated at the discretion of the therapist in consultation with the appropriate medical practitioner as there have been anecdotal reports of adverse outcomes, most especially (but not exclusively) associated with treatments to the neck and upper thoracic areas 4. Avoid active epiphyseal regions in children (though there is no direct evidence of adverse effect) 5. The use of abdominal electrodes during labour may interfere with foetal monitoring equipment and is therefore best avoided.  TENS APPLICATION STEP RATIONAL Position and Ensure comfortable body positioning. instruct patient Instruct the patient not to touch the device, cables, and applicators and to call for assistance if necessary Prepare treated Clean the skin surface in the area of the stimulating electrodes with rubbing area alcohol, or water and soap, to remove impurities and reduce skin impedance. Clip hair to ensure optimal electrode–skin coupling Select stimulator Choose between cabinet (in clinic therapy) or portable (bedside or home type. therapy) device. Select mode of Select between the following modes: conventional, acupuncture like, brief delivery intense, burst, or modulation.  TENS APPLICATION STEPS RATIONAL Select electrode For postoperative conditions: Use sterile, disposable type. electrodes. For all the other conditions: Use reusable, nonsterile electrodes. Prepare Cover surface with a thin and evenly distributed coating of stimulating electroconductive gel to optimize conduction at the electrode. electrode–skin interface. Note that sterile electrodes are pre-gelled. Nonsterile electrodes can also be pre-gelled and ready for use. Place the Select one the following electrode placements: (1) on top of electrodes. the painful area, (2) around the painful area, (3) along the dermatome(s) corresponding to the painful area, (4) over acupuncture points, and (5) over trigger points. Regularly change electrode placement to avoid contact dermatitis  TENS APPLICATION STEP RATIONAL Attach and Attach the electrode to the skin using hypoallergic tapes or connect pre-cut self-adhesive patches. Connect the electrodes to the electrodes. stimulator circuit outputs using either regular or bifurcated lead wires or cables of various lengths Apply treatment. Ensure adequate monitoring. If home treatment, use a portable battery-operated device, and make sure to give to your patient a written sheet of directives to follow with regard to the overall application of TENS. Conduct post- Remove the electrodes. Inspect the skin area exposed to the treatment electrodes for any unexpected response. Wash and dry the inspection. treated surface areas. Wash and dry reusable electrodes.  TENS APPLICATION Step Rational Ensure post Discard all reusable electrodes after 6 months of use. treatment equipment Transmission of microorganisms is likely if suction electrodes maintenance. and sponges are used; these should be disinfected with 70% isopropyl alcohol after treatment of each patient to avoid cross-infection from one patient to another. ELECTRODE FIXATION Electrode fixed to the skin with adhesive tape or bandage into place. A conducting gel is applied between electrode and skin The leads from the TENS UNIT are concealed and fixed in the clothing if home treatment is being given. convenient ready-gelled adhesive electrode are available. REFERENCES Electro physical agents third edition. Physical Agents in Rehabilitation An Evidence-Based Approach to Practice Fifth Edition Michelle H. Cameron, MD, PT, MCR chapter #13 Textbook of Electrotherapy : second edition ,Jagmohan Singh PhD Professor and Principal Gian Sagar College of Physiotherapy Ram Nagar, Rajpura Patiala, Punjab, India chapter #2 page,133