Direct Comparison of Spinal Cord Stimulator Parameter Settings

Direct Comparison of Spinal Cord Stimulator Parameter Settings

(Primary)

1. To compare the clinical effects and side effects of two different stimulation strategies that do not produce any sensory percept (1000 Hz and placebo) on clinical benefit for electrodes implanted for chronic pain as measured by the Visual Analog Pain Scale for back and leg pain, the Brief Pain Inventory, the 36-Item Short Form Survey (SF-36), and the Pain Vigilance and Awareness Questionnaire.

   (Secondary)

2. To compare the clinical effects of the subthreshold (paresthesia-free) stimulation patterns with conventional (paresthesia-producing) stimulation patterns to evaluate the necessity of paresthesias and current amplitudes on clinical benefit for pain.

3. To identify the ability of subthreshold high-frequency to improve axial pain or the affective component of pain.

This is a prospective, randomized, double-blind study of different stimulation patterns in patients undergoing implantation of neurostimulator systems for chronic medically intractable neuropathic pain. Research participants will be individuals who have undergone implantation of neurostimulator electrodes into the spinal column or peripheral nervous system for clinical treatment of neuropathic pain. All patients will already have undergone empiric programming of the stimulator using conventional settings (typically 40-60 Hz, 350-450 usec pulse width). However, other stimulation parameters, including high-frequency stimulation, are also feasible and FDA-approved using the implanted device, and it is possible to do this without producing a sensory percept, which makes it possible to test efficacy in a double blind manner. For this study, two different stimulation parameters will be tested during four two-week periods: 1000 Hz and placebo. Clinical response and side effect profile for each setting will be measured.

Inclusion Criteria:

• Age 18-75 years
• Diagnosis of chronic neuropathic pain for which placement of electrodes into the spinal column is planned for clinical indications (failed back surgery syndrome, peripheral neuropathy or complex regional pain syndrome)
• History of implantation of spinal cord stimulation system with rechargeable implanted neurostimulator

Exclusion Criteria:

• Significant dementia or other condition preventing informed consent by the patient.
• Current drug or alcohol abuse or dependence.
• Uncontrolled depression or anxiety or failure to pass psychological screening for spinal cord stimulation.
• Inability or unwillingness to cooperate with clinical testing.