Jeffrey M. Sieracki

Spinal cord stimulation electrode design: prospective, randomized, controlled trial comparing percutaneous and laminectomy electrodes-part I: technical outcomes.

OBJECTIVE The clinical use of spinal cord stimulation for treatment of chronic intractable pain has been increasingly successful because of recent technical improvements, particularly the development of multiple-contact electrodes supported by programmable implanted pulse generators. Contemporary electrodes can be placed percutaneously in some cases and require a limited laminectomy in other cases. METHODS We performed a prospective, randomized, controlled trial comparing two prototypical electrode designs, using a computerized system that allows direct patient interaction and quantitative measurements. A series of 24 patients with chronic lumbosacral pain syndromes first underwent testing with percutaneous four-contact electrodes and then underwent implantation, at the same spinal level, of one of two different electrode configurations; 12 patients received a new percutaneous four-contact electrode of the same design and 12 received an insulated four-contact array, which was implanted via laminectomy. RESULTS The insulated array performed significantly (P = 0.0005–0.0047) better than the temporary percutaneous electrode for the same patients, according to all three measures tested (ratings of paresthesia coverage of pain, coverage calculated from patient drawings, and amplitudes), at the “usage” amplitude for the three standard bipoles examined. The insulated array also performed significantly (P = 0.0000–0.026) better than the permanent percutaneous electrode in terms of coverage ratings and amplitude requirements. Low back coverage ratings were significantly better for the insulated array than for the temporary percutaneous electrode, and scaled amplitudes necessary for low back coverage were significantly better for the permanent percutaneous electrode than for the temporary electrode. In comparison with the percutaneous temporary electrode, at subjectively identical stimulation intensities, the permanent insulated array required significantly lower amplitude. CONCLUSION We can immediately infer from these technical data that the use of an insulated array, in comparison with a percutaneous electrode, would double battery life. Extended follow-up monitoring will be required to assess the extent to which the technical advantages we observed for the insulated array might be associated with improved clinical outcomes.

Spinal Cord Stimulation for Axial Low Back Pain : A Prospective, Controlled Trial Comparing Dual With Single Percutaneous Electrodes

Study Design. A prospective, controlled, clinical trial comparing single and dual percutaneous electrodes in the treatment of axial low back pain from failed back surgery syndrome. Objectives. To clarify technical requirements and test the hypothesis that placing two linear arrays in parallel, thereby doubling the number of contacts, improves outcome. Summary of Background Data. Technical improvements have enhanced outcomes of spinal cord stimulation for chronic axial low back pain. Dual, parallel electrodes reportedly improve these outcomes. Methods. Acting as their own controls, 20 patients who passed screening with single, 4-contact electrodes received permanent dual, 4-contact electrodes with 7- or 10-mm intercontact distances at the same vertebral level(s). We quantified and compared the technical and clinical results of the single and dual electrodes, adjusting stimulation parameters to specific psychophysical thresholds. Results. Single electrodes provided significant (P < 0.01) advantages in patient- and computer-calculated ratings of pain coverage by paresthesias and in the scaled amplitude necessary to cover the low back, compared with dual 7-mm electrodes. Slight advantages without statistical significance were observed for the single over the dual 10-mm electrodes. Amplitude requirements were significantly lower for the single electrode than for either dual electrode. At long-term follow-up, 53% of patients met the criteria for clinical success. Conclusions. While we observed disadvantages for dual electrodes in treating axial low back pain, we achieved technical success with single or dual electrodes in most patients and maintained this success clinically with dual electrodes in 53%.

607 SPINAL CORD STIMULATION WITH INTERLEAVED PULSES: A RANDOMIZED, CONTROLLED TRIAL

extensive personal experience in the use of neuromodulation procedures has been working to settle the “how to do it” in this not well known therapy in our country. Objectives: As a consensus statement, this guideline has established several goals: 1. To gather all the knowledge available about neurostimulation 2. Teaching tool 3. To help care providers in their decision making process 4. To standardized clinical practice in order to obtain better results and comparable data for analysis Method: By discussing literature available and based on the group members personal experiences, and using the EBM criteria. Results: The SGNM has created the Spanish Guidelines for Neurostimulation containing 8 chapters and 2 appendix as follows: Chapter 1: Introduction. Objectives. Chapter 2: Desirable characteristics for clinicians and facilities. Chapter 3: Psychological testing. Chapter 4: Informed consent and general information. Chapter 5: Preparation for the implant. Chapter 6: Implant technique. Chapter 7: Follow up visit. Chapter 8: Complications. Appendix I: Programming for Spinal Cord Stimulation. Appendix II: Cost-Effectiveness analysis. Conclusion: There is no other document in our country that summarizes the theoretical and practical knowledge about electrical stimulation to treat chronic pain. We believe this project will be an approach for clinicians to this field, and a challenge for the SNMG to review this and many other topics related to neurmodulation therapies.