Acute Human Study: StimRouter for Peripheral Nerve Stimulation of Discrete Peripheral Nerves

Inclusion Criteria: * 18 years of age or older * Chronic peripheral pain persisting for greater than or equal to 3 months diagnosed previously as a mononeuropathy of the median nerve at the level of the carpal tunnel (i.e., diagnosed CTS) * Average chronic pain level greater than or equal to 5/10 \[on 0-10 numeric rating scale (NRS) (BPI#14)\], where such pain is attributed to injury, irritation, or entrapment of the median nerve at the level of the carpal tunnel (i.e., diagnosed CTS) * Failure of a single prior carpal tunnel release surgery to provide relief, where such failed surgery was performed greater than or equal to study entry * Able to tolerate stimulation (TENS) * Temporary pain relief is achieved by local anesthetic block of the target median nerve suspected to be the source of chronic pain symptoms * Ability to give informed consent and understand study requirements * Ability to quantify pain using a 0-10 numeric rating scale \[A screening tool will be used to ensure that subjects can rate 3 common pain scenarios (mosquito bite, stubbed toe and broken bone) on a 0-10 NRS relative to each other, with mosquito bite \< stubbed toe \< broken bone\] * Willing and able to understand and comply with all study-related procedures during the course of the study * Motivated to maintain an accurate diary for the study duration Exclusion Criteria: * Metal implants in the forearm * Active infection * Active or existing skin disorder or irritation which, at the physician's discretion, contraindications use of skin gel electrodes * Allodynia * Regular use of antiplatelet medications \[e.g., aspirin, ticlopidine (Ticlid), clopidogrel (Plavix), tirofiban (Aggrastat), and eptifibatide (Integrilin)\] * Anticoagulated (taking warfarin or heparin, including fractionated heparin) or has a bleeding disorder * Cardiac pacemaker * Implanted neurostimulator (e.g., spinal cord, deep brain, vagus nerve stimulator) or implanted pump or infusion device * History of cardiac arrhythmia with homodynamic instability * Untreated drug habituation or dependence * Psychologically or medically unstable * Uncontrolled seizures (averaging \> 2 seizures per month) * Pregnant or plan on becoming pregnant or breastfeeding during the study period * Currently require, or likely to require, diathermy and/or MRI during the study duration * History of adverse reactions to local anesthetic (e.g., lidocaine)