Tsunami DRG High Frequency Stimulation Study

Prospective, double blinded, randomized, clinical study investigating the effects of high frequency SCS over exiting nerve roots at T9 for the treatment of chronic back or back and leg pain.

All subjects will have two permanent stimulators placed over the exiting nerve roots at T9 at the implant visit. The stimulators can easily be removed for non-responders. High frequency stimulation is typically programmed below sensory threshold. This type of stimulation lends itself to a placebo-controlled trial. For this study subjects will be randomized 1:1 at enrollment into a high frequency or sham group. Neither the subjects nor experimenters will be made aware of their randomization assignment for at least the first month of the trial. Subjects belonging to both groups will be unblinded to their assignment at the 1-month or a later visit (including unscheduled visit) if they have a VAS \> 30 mms. Subjects belonging to the sham group will be reprogrammed with HF stimulation at this point. Subjects belonging to the HF stimulation group will keep stimulating with HF. Subjects reporting a VAS \< 30 mms will continue to be blinded.

Eligibility Criteria:
Inclusion criteria

* Subject is ≥ 18 years of age at time of informed consent;
* Subjects have been diagnosed with predominant, chronic, intractable back pain with a VAS \> 50 mm (on a 100-mm scale);
* Subjects have been diagnosed with predominant, chronic, intractable back pain for at least 6 months before study participation;
* Based on the medical opinion of the Principal Investigator, subject has a stable pain medication regiment;
* Based on the medical opinion of the Principal Investigator, there is no evidence of anatomic abnormalities that could jeopardize the placement of the device or pose a hazard to the subject;
* Subject is willing to undergo surgical implant procedure, attend visits as scheduled, and comply with the study requirements;
* Subject is willing and able to operate the patient programmer, recharging equipment and has the ability to undergo study assessments and provide accurate responses;
* Based on the opinion of the implanter, subject is a good surgical candidate for the implant procedure;
* Subject is male or non-pregnant female;
* Subject is deemed to be neuro-psycho-socially appropriate for implantation therapies based of the assessment of a clinical psychologist and principal investigator, using face-to-face encounters and the psychological testing described in the measures;
* Patient is capable of giving informed consent.

Exclusion criteria

* Obvious mechanical instability related to pain (diagnosed by imaging taken within the past 6 months);
* Unresolved malignancies in the last six months;
* Subject has post-herpetic neuralgia (shingles);
* Subject has an active systemic infection or is immune-compromised;
* Based on the medical opinion of the Principal Investigator the subject has other psychological conditions (e.g., psychosis, suicidal ideation, borderline personality disorder, somatization, narcissism), other health conditions (e.g., substance abuse, another chronic condition requiring the regular use of opioid medication), or other legal concerns that would preclude his/her enrollment in the study or potentially confound the results of the study;
* Subject is currently enrolled in or plans to enroll in any concurrent drug and/or device study while participating in this study;
* Insulin-dependent diabetic who is not controlled through diet and/or medication (determined by the physician) or non-insulin dependent diabetic who is not well controlled through diet and/or medication;
* Bleeding complications or coagulopathy issues;
* Pregnant/lactating or not using adequate birth control;
* A life expectancy of less than one year;
* Any active implanted device whether turned off or on;
* A previous SCS experience;
* Conditions requiring Magnetic Resonance Imaging (MRI) evaluation or diathermy procedures.