Insula Neuromodulation for Chronic Neuropathic Pain

Inclusion Criteria: 1. Men and women, between 18 and 80 years, inclusive 2. Subjects who are able and willing to give consent and able to attend all study visits 3. The pain is: * chronic with ≥6 month duration * severe is defined as: 'average' NPRS score of ≥ 5 out of 10 at current visit and the subject reports having a similar level of pain for at least the past two months * disabling and has resulted in an inability to work or perform ADLs in the home * medication-refractory to adequate trials of at least 3 prescription medications (including at least one current or past opioid) commonly used for symptomatic relief of pain. An adequate medication trial is defined as a therapeutic dose of each medication without sufficient effect. * treatment-resistant and cannot be treated or has failed procedures including interventional therapies with injections, spinal neuromodulation with medication infusion or stimulation, and neurosurgical ablation surgery. 4. The pain is neuropathic or predominantly neuropathic if mixed components. * Subject suffering from a pure neuropathic pain syndrome will be included if the pain has resulted from a specific injury including trauma, ischemia, hemorrhage, infection, tumor or iatrogenic to either the peripheral (nerve, spinal root, plexus, cranial nerve) or to the central nervous system (spinal cord or brain) Etiologies include: * Poststroke pain * Thalamic pain * Spinal cord injury * Brachial plexus injury or limb avulsion * Peripheral nerve injury or painful neuropathy * Postherpetic neuralgia, Tolosa Hunt syndrome, or cavernous sinus syndromes * Trigeminal neuropathic pain (not trigeminal neuralgia) 5. Insula region must be apparent on MRI so that direct targeting can be performed for SEEG and DBS electrode placement. 6. Able to communicate and report sensations during all stimulation testing 7. Stable prescribed doses of all symptomatic pain medications for 30 days prior to study entry and for the duration of the study. 8. Inclusion and exclusion criteria have been agreed upon by the principal investigator and the pain psychologist, both of whom have interviewed, examined and if appropriate provided psychotherapeutic intervention to the subject. Exclusion Criteria: 1. Idiopathic pain syndromes will be excluded. Examples include: 1. Fibromyalgia syndrome 2. temporomandibular joint disorders 3. irritable bowel syndrome 4. chronic headaches 5. interstitial cystitis 6. chronic pelvic pain 7. whiplash-associated disorders 2. Sub…