This study aims to determine whether ongoing BurstDR spinal cord stimulation (SCS) provides pain relief beyond sham stimulation in patients with chronic pain who are established responders to BurstDR therapy. Participants already implanted with an SCS system and experiencing stable clinical benefit from BurstDR will undergo both active stimulation and sham stimulation in a randomized, double-blind crossover design. Each participant will therefore serve as their own control. The primary question is whether pain intensity is lower during active BurstDR stimulation compared with sham stimulation. The study will also evaluate treatment satisfaction, patient-reported changes in sleep, mood, daily activity and social activity, the effectiveness of blinding, and short-term safety and tolerability.
BurstDR spinal cord stimulation is a paresthesia-free neuromodulation therapy used for the treatment of chronic pain. Although clinical studies have demonstrated beneficial outcomes with BurstDR therapy, the specific contribution of ongoing stimulation, separate from contextual effects, expectation, natural symptom variation, and other nonspecific influences, remains incompletely defined. This study uses a randomized, double-blind, two-period crossover design in patients who are already implanted with a spinal cord stimulation system and have an established clinical response to BurstDR therapy. Studying established responders avoids potential confounding associated with implantation, postoperative recovery, and initial programming and optimization, and allows the effect of ongoing stimulation to be evaluated under controlled conditions. Before the randomized treatment periods, each participant will complete a baseline observation under their established active BurstDR settings, followed by a washout period with stimulation switched off. Participants will then undergo two randomized treatment periods: one with active BurstDR stimulation and one with sham stimulation, separated by a second washout period. The order of the two conditions will be randomly assigned, allowing each participant to serve as their own control and thereby reducing the influence of between-patient variability. During the active condition, stimulation will be delivered using the participant's established clinically effective BurstDR program. During the sham condition, stimulation output will be switched off while study procedures, participant contacts, and data collection will otherwise remain comparable between conditions. Because BurstDR stimulation is intended to be paresthesia-free, it provides an opportunity for blinded comparison with sham stimulation. Before the randomized treatment phase, a standardized perceptibility assessment will be performed to confirm that participants cannot reliably perceive whether stimulation is active. Device access and information that could reveal treatment allocation will be restricted, and treatment programming will be performed by designated study personnel who are not involved in outcome assessment or the primary analysis. The crossover and washout design is intended to minimize residual stimulation effects and provide a controlled assessment of the specific contribution of ongoing BurstDR therapy in patients who have previously demonstrated clinical benefit from this treatment.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
QUADRUPLE
Enrollment
28
Active BurstDR spinal cord stimulation is delivered for 7 consecutive days using each participant's established clinically effective stimulation settings. Electrode configuration, pulse pattern, pulse width, frequency structure, and amplitude are maintained according to the participant's established therapeutic program, with any adjustment required to maintain imperceptible stimulation completed before the randomized treatment periods.
During sham stimulation, the implanted spinal cord stimulation system remains in place but stimulation output is switched off for 7 consecutive days. The participant-facing programmer is locked and visible device information that could reveal treatment allocation is masked. Study contacts, diary assessments, and follow-up procedures are otherwise equivalent to those during active stimulation.
University Hospital of Northern Sweden
Umeå, Sweden
Within-Participant Difference in Period-Level Median Numeric Rating Scale Pain Intensity Between Active BurstDR and Sham
Pain intensity is recorded twice daily, morning and evening, using an 11-point Numeric Rating Scale (NRS; 0=no pain to 10=worst pain) for each predefined pain area during each randomized treatment period. All available NRS ratings within each participant and treatment period are pooled, and the period-level median is calculated. The primary outcome is the within-participant paired difference between sham and active BurstDR stimulation (Sham minus Active), with positive values favoring active BurstDR. Baseline-day NRS data are not included in the primary endpoint.
Time frame: During each 7-day randomized treatment period (Days 5-11 and Days 16-22 after baseline)
Within-Participant Difference in End-of-Period Treatment Satisfaction Score Between Active BurstDR and Sham
Overall treatment satisfaction is assessed on a 0-10 scale at the end of each 7-day randomized treatment period. Scores obtained following active BurstDR and sham stimulation are compared within each participant.
Time frame: At the end of each 7-day randomized treatment period (Day 11 and Day 22 after baseline)
Within-Participant Difference in Period-Level Median Patient Global Impression of Change Score for Sleep Quality
Patient Global Impression of Change for sleep quality is assessed once daily using a 5-point scale during each randomized treatment period. For each participant and treatment period, the median of all available daily sleep ratings is calculated and compared between active BurstDR and sham stimulation.
Time frame: Daily during each 7-day randomized treatment period (Days 5-11 and Days 16-22 after baseline)
Within-Participant Difference in Period-Level Median Patient Global Impression of Change Score for Mood
Patient Global Impression of Change for mood is assessed once daily using a 5-point scale during each randomized treatment period. For each participant and treatment period, the median of all available daily mood ratings is calculated and compared between active BurstDR and sham stimulation.
Time frame: Daily during each 7-day randomized treatment period (Days 5-11 and Days 16-22 after baseline)
Within-Participant Difference in Period-Level Median Patient Global Impression of Change Score for Daily Activity
Patient Global Impression of Change for daily activity is assessed once daily using a 5-point scale during each randomized treatment period. For each participant and treatment period, the median of all available daily ratings is calculated and compared between active BurstDR and sham stimulation.
Time frame: Daily during each 7-day randomized treatment period (Days 5-11 and Days 16-22 after baseline)
Within-Participant Difference in Period-Level Median Patient Global Impression of Change Score for Social Activity
Patient Global Impression of Change for social activity is assessed once daily using a 5-point scale during each randomized treatment period. For each participant and treatment period, the median of all available daily ratings is calculated and compared between active BurstDR and sham stimulation.
Time frame: Daily during each 7-day randomized treatment period (Days 5-11 and Days 16-22 after baseline)
Perceptibility of Active BurstDR Stimulation Before Randomized Treatment
A standardized perceptibility assessment using brief randomized stimulation ON/OFF intervals is performed before the first randomized treatment period to verify that the participant cannot reliably perceive active BurstDR stimulation.
Time frame: At the baseline/programming visit, before the 1-day baseline diary and before Washout 1
Number of Participants With Adverse Events, Serious Adverse Events, and Stimulation-Related Complaints
Adverse events, serious adverse events, and stimulation- or device-related complaints are recorded during study participation. Events will be summarized descriptively and, where feasible, according to whether they occurred during active BurstDR stimulation, sham stimulation, or washout.
Time frame: From baseline through Day 22 after baseline (completion of the second randomized treatment period)
Participant-Reported Perception of Stimulation During Each Randomized Treatment Period
At the end of each randomized treatment period, participants are asked whether they felt stimulation or paresthesia at any time during that treatment period. Responses are summarized by treatment condition to assess the integrity of masking.
Time frame: At the end of each 7-day randomized treatment period (Day 11 and Day 22 after baseline)
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