TENS,+Spinal+Cord+Stimulators,+Neuroablation

**TENS(Transcutaneous Electrical Nerve Stimulation)**

An external peripheral neuromodulation system.  What does it do? - TENS provides low-voltage electrical pulses to the nervous system through electrodes placed on the skin  How does it work? – Gate Theory postulates that the stimulation of larger myelinated sensory A fibers with high frequency closes the gate to the transmission of smaller slower pain fibers to the CNS  Benefits – no side effects, it is a safe, non-invasive treatment that can be self-applied.  Uses and Modes – Acute pain - High Frequency + short pulse width – may use up to 2 hours, multiple times per day depending on response and duration of analgesia Chronic pain – low rate TENS – slower analgesic effect acting on C Fibers and indirectly the hypothalamus. Endorphins are released from the pituitary and bind to opiate receptors in the brain – 30-45 minutes for shorter duration, 2-6 hours for longer duration, used once per day  Increases in intensity are titrated to the patient perception of strong paresthesias w/o muscle contraction Placebo effect is 30%(similar to most medications)  <span style="font-family: Verdana,sans-serif;">Indications – Acute pain, Chronic pain, phantom limb pain, postop pain, ischemic pain, raynaud’s disease, post herpetic neuralgia, osteoarthritis, neuropathic pain, rheumatoid arthritis <span style="font-family: Verdana,sans-serif;"> <span style="font-family: Verdana,sans-serif;">Contraindictions – cardiac pacer, over carotid sinus(vaso vagal), pregnant uterus(preterm labor), pharyngeal area(laryngospasm) <span style="font-family: Verdana,sans-serif;"> <span style="font-family: Verdana,sans-serif;">Precautions – anterior neck pain, cardiac disease, epilepsy, over eyes, mucosal surfaces, stroke, cns disorders, incompetent patients, children, wounds

<span style="font-family: Verdana,sans-serif;">Neuromodulation at the spinal level <span style="font-family: Verdana,sans-serif;"> <span style="font-family: Verdana,sans-serif;">What does it do? low-voltage electrical pulses to the nervous system through electrodes placed in the epidural space <span style="font-family: Verdana,sans-serif;"> <span style="font-family: Verdana,sans-serif;">How does it work? Many theories on the mechanism of action of spinal cord stimulation have been suggested, including activation of gate control mechanisms, conductance blockade of the spinothalamic tracts, activation of supraspinal mechanisms, blockade of supraspinal sympathetic mechanisms, and activation or release of neuromodulators. <span style="font-family: Verdana,sans-serif;"> <span style="font-family: Verdana,sans-serif;">Benefits – reversible, reduction in medication, portable improvement in daily activities <span style="font-family: Verdana,sans-serif;"> <span style="font-family: Verdana,sans-serif;">Caveat - Patient population should be psychologically stable and have exhausted all traditional less invasive treatments. Not for patient with drug seeking behavior. <span style="font-family: Verdana,sans-serif;"> <span style="font-family: Verdana,sans-serif;">Technique - Placed anywhere along the epidural space from cervical to caudal. Patient is positioned sitting, lateral, or prone. Patient is awake for feedback. Tuohy needle is used to enter the epidural space to guide the electrode to the midline of the desired spinal segment using fluoroscopy. Trial stimulation to confirm perception over the painful area, often more than one electrode is required. Trial is for 48 -72 hours to assess adequate pain relief <span style="font-family: Verdana,sans-serif;"> <span style="font-family: Verdana,sans-serif;">Types – 1. Total implantable electrode and pulse generator system 2. total implantable electrode and receiver antenna used with and external pulse g <span style="font-family: Verdana,sans-serif;"> <span style="font-family: Verdana,sans-serif;">enerator. <span style="font-family: Verdana,sans-serif;">Indications- Failed back surgery syndrome, peripheral vascular occlusive disease, spinal cord injury, chronic regional pain syndrome, phantom limb pain, intractable angina, abdominal pain <span style="font-family: Verdana,sans-serif;"> <span style="font-family: Verdana,sans-serif;">Contraindications – sepsis, anticoagulation, psychological comorbidity, patient refusal, MRI needs, uncooperative, inability to control device, drug use, demand cardiac pacemaker <span style="font-family: Verdana,sans-serif;"> <span style="font-family: Verdana,sans-serif;">Complications – CSF leak, infection, subcutaneous pocket malposition, postdural puncture headache, neuritis or nerve root irritation, high rate of hardware revisions and electronic reprogramming
 * <span style="font-family: Verdana,sans-serif;">Spinal cord stimulation **

<span style="font-family: Verdana,sans-serif;">How does it work? Cryotherapy, radiofrequency, or chemicals(alcohol or phenol) injected in close proximity to destroy neural structures that are capable of transmitting pain for longer lasting analgesia. <span style="font-family: Verdana,sans-serif;"> <span style="font-family: Verdana,sans-serif;">Phenol causes nerve destruction by inducing protein precipitation. There is loss of cellular <span style="font-family: Verdana,sans-serif;"> fatty elements, separation of the myelin sheath from the axon, and axonal edema. Alcohol has similar mechanism but is better at destroying nerve cell bodies. Chemical ablations include: <span style="font-family: Verdana,sans-serif;">Neurolytic saddle block, Phenol epidural block, Celiac plexus block, Neurolytic lumbar sympathetic block, Neurolytic peripheral nerve blocks, Local neurolytic injection <span style="font-family: Verdana,sans-serif;"> <span style="font-family: Verdana,sans-serif;">Radiofrequency: The lesion is formed once the neural temperature exceeds 45 degrees centigrade. The temperature is monitored and wattage is adjusted to the desired level, which in turn determines the size of the lesion <span style="font-family: Verdana,sans-serif;">Used at trigeminal ganglion, spinal cord, dorsal <span style="font-family: Verdana,sans-serif;"> root entry zone, dorsal root ganglion, sympathetic chain, facet joints, and peripheral nerves <span style="font-family: Verdana,sans-serif;"> <span style="font-family: Verdana,sans-serif;">Benefits- reduction of opiod doses, prolonged benefit lasting 9-14 months until nerve regenerates <span style="font-family: Verdana,sans-serif;"> <span style="font-family: Verdana,sans-serif;">Indications – Severe cancer pain, Chronic intractable pain <span style="font-family: Verdana,sans-serif;"> <span style="font-family: Verdana,sans-serif;">Complications – Pain at the needle entry site, neuritis causing pain that is worse than before, infection, intrathecal injection, motor paralysis, long term numbness, bowel or bladder incontinence
 * <span style="font-family: Verdana,sans-serif;">Neuroablation **