SCS Dosing Study

Research Goal

Medtronic is one of the world’s largest medical device companies with operations in over 140 countries. Their Spinal Cord Stimulator device, RestoreSensor®️, is implanted in patients to relieve chronic back and limb pain using electrical impulses to simulate nerve activity. The purpose of this study was to determine the minimum high dose amplitude settings for the device to relieve pain. Research Coordinators were selected at eligible study sites nationwide; I was selected to lead the study at our clinic site, Georgia Pain and Wellness Center. The following data includes the general study plan as well as some results from our site.

Study Background

The RestoreSensor device attaches 16 electrodes into the spinal cord with two columns of 8. Program settings are adjustable to the user as well as study monitors. An anode (+) and a cathode (-) can be placed at any of these electrodes to create a circuit while the current can be adjusted for wavelength, frequency and voltage amongst other options. These settings vary per patient needs.

Key questions that were analyzed:

1) What are their initial ideal device settings per participant?

2) Over the course of the study, how will the setting changes affect the pain levels of each participant?

3) Will the patient discover and retain more ideal settings post-study?

Methodology

15-month study to assess a pre-selected group of settings on patient pain through various qualitative and quantitative assessments. While the study was open for over a year, participation was only needed for 12 weeks per individual. Quantitative and qualitative data was to be collected through pain diaries and VAS (Visual Analogue Scale). This information would be entered through a research portal called Oracle for Medtronic moderator access.

After identifying and recruiting patients* in our clinic with pre-programmed high dose settings (90 μs and 1000 Hz), the goal was to lead them through 6-study related visits. These visits would consist of Screening Visit, Baseline/Programming Visit, 3 Additional Programming Visits and a Final Study Visit.

The high dosage patients were then subjected to a single-blind study where only the stimulation amplitudes were titrated down 20% per visit for 2 weeks each to see if they noticed a difference in pain relief.

*due to the nature of the study and the associated HIPAA laws, patient data cannot be disclosed at this time

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Phase 1: Recruitment / Screening Visit

Phase 2: Baseline/Programming Visit

Phase 3: Additional Programming Visits

Phase 4: Final Study Visit and Conclusions

Recruitment / Screening

Eligibility Criteria:

22+ years age, 1+ month of device implant, high dosage setting majority use (>50%), stable medication through study, able to consent, comply and undergo threshold testing.

Method of Recruitment:

1) Use EMR system and site documentation to identify patients with appropriate settings (last updated)

2) Create an Excel document that lists patient names, current information and most recent contact

3) Outreach via phone calls and consultation during check-up visits, obtain consent

We were able to identify 31 potential candidates who were current patients to our site for the study. Out of these 31 contacts, 23 patients were able to be contacted through these methods. From those 23 patients, 18 were willing to participate in the initial screening. Out of the 18 willing patients, 10 were able to make it to the first screening.

Baseline / Programming Visit

The criteria to proceed with a 2-week follow up baseline visit:

1) the patient must have a VAS of less than 4 on a scale of 1-10

2) experience general relief from the therapy as documented in their SSA (Satisfaction and Sensation Assessment). This survey included questions such as:

“Overall, how satisfied or unsatisfied are you with this therapy?”

“Have you felt any stimulation sensations?”

3) documented more than 5 of the 7 days in their pain diaries

Once this criteria is met, Programming Visit #1 takes place and the patient is sent home with an 80% titration of their amplitude while maintaining the same high dosage (90 μs / 1000 Hz).

From the 10 potential candidates that were able to make it to the screening, 4 candidates passed the inclusion and exclusion criteria with consent. These candidates were then given their SSA pain diaries and were consulted on how to complete them before their Baseline visit.

Additional Programming Visits

3 additional visits are required after the baseline visit to titrate the amplitudes down to the following percentages:

60%

40%

20%

For each visit and titration, participants were expected to complete a pain assessment using their diaries. The VAS pain scale as well as descriptions of their day to day movements were documented in Medtronic’s online portal.

From the 4 participants who made it to the Baseline visit, only 2 of them had VAS scores under 4 and reported relief from their high dosage settings. These 2 candidates were moved through the 60% programming session.

Final Study Visit

For the final study visit, completed SSA’s were collected and the devices were interrogated to gather reports on the initial active therapy settings.

The 2 patients that were able to move through the first baseline and programming session were disqualified from the study due to incorrect or incomplete data entry. The rest of our participation in this study focused on outsourced recruitment to local facilities. We were unable to find other participants.

The following settings were tested to make sure perception thresholds were legitimate and varied from any placebo effect.

Conclusion

A public link to the study was made available here with anonymity to the participating individuals:

https://clinicaltrials.gov/ProvidedDocs/11/NCT03284411/Prot_000.pdf