A Safety and Effectiveness Trial of Spinal Cord Stimulation of the Dorsal Root Ganglion for Chronic Lower Limb Pain

The purpose of this study is to evaluate the safety and effectiveness of the AXIUM Neurostimulator System for the treatment of chronic lower limb pain in persons diagnosed with Complex Regional Pain Syndrome (CRPS) or Peripheral Causalgia (PC).

The ACCURATE study is a prospective, randomized, controlled, multicenter clinical trial designed to assess the safety and efficacy of the Spinal Modulation Axium Neurostimulator System as an aid in the management of chronic, intractable pain of the lower limbs, including unilateral or bilateral pain associated with one of the following conditions: Complex Regional Pain Syndrome (CRPS) or Peripheral Causalgia (also referred to as CRPS Type II).

Enrolled subjects were diagnoses with CRPS or peripheral causalgia; experienced pain for at least six months; and failed to achieve adequate pain relief from at least two prior pharmacologic treatments.

All subjects had a temporary trial neurostimulator (TNS). If the subject was a treatment success at the end of TNS they were scheduled for the fully implantable neurostimulator (INS) implant procedure. If not, subjects were exited from the study.

Eligibility Criteria:
Inclusion Criteria:

1. Subject is male or female between the ages of 22 and 75 years
2. Subject is able and willing to comply with the follow-up schedule and protocol
3. Subject has chronic, intractable pain of the lower limb(s) for at least 6 months
4. Subjects are diagnosed with complex regional pain syndrome (CRPS) and/or peripheral causalgia
5. Subjects have a minimum Visual Analog Scale (VAS) greater than or equal to 60 mm in the area of greatest pain in the lower limbs.
6. Subject has failed to achieve adequate pain relief from at least 2 prior pharmacologic treatments from at least 2 different drugs classes
7. Subject has had stable neurologic function in the past 30 days
8. In the opinion of the Investigator, the subject is psychologically appropriate for the implantation of an active implantable medical device
9. Subject is able to provide written informed consent

Exclusion Criteria:

1. Back pain is the greatest region of pain as measured on the baseline VAS.
2. Female subject of childbearing potential is pregnant/nursing, plans to become pregnant or is unwilling to use approved birth control
3. Subject has exhibited escalating or changing pain condition within the past 30 days as evidenced by Investigator examination
4. Subject is currently involved in medically related litigation, including workers compensation
5. Subject has had corticosteroid therapy at an intended site of stimulation within the past 30 days
6. Subject's pain medication(s) dosage(s) are not stable for at least 30 days
7. Subject has had radiofrequency treatment of an intended target Dorsal Root Ganglion within the past 3 months
8. Subject has previously failed spinal cord stimulation therapy
9. Subject currently has an active implantable device including implantable cardioverter defibrillator, pacemaker, spinal cord stimulator or intrathecal drug pump or subject requires magnetic resonance imaging (MRIs) or diathermy
10. Subject has pain only within a cervical distribution
11. Subject has cognitive, physical or sensory impairment that, in the opinion of the Investigator, may limit their ability to operate the device
12. Subject currently has an indwelling device that may pose an increased risk of infection
13. Subject currently has an active systemic infection.
14. Subject has, in the opinion of the investigator, a medical comorbidity that contraindicates placement of an active medical device
15. Subject has participated in another clinical investigation within 30 days
16. Subject has a coagulation disorder or uses anticoagulants that, in the opinion of the Investigator, precludes participation
17. Subject has been diagnosed with cancer in the past 2 years
18. Imaging (MRI, CT, x-ray) findings within the last 12 months that, in the Investigator's opinion, contraindicates lead placement
19. Subject is a prisoner