Introduction: "Remission" refers to the absence of clinically significant signs and symptoms of an incurable disease. Although remission is utilized in specialties such as psychiatry and oncology, it has not been applied to interventional pain management. We introduce the concept of remission from chronic pain and apply it to the SENZA-RCT data.
Methods: We defined remission as a sustained VAS pain score of 2.5 or less out of 10.0. This was based on pain scores of 4.0 or greater warranting pharmaceutical intervention and patients seek treatment when their pain level is >2.5. Furthermore, a score of 2.5 or less results in minimal impact on the patient activities of daily living (ADLs) and quality of life (QOL).
This definition was applied to the SENZA-RCT study, a prospective multicenter randomized controlled pivotal trial comparing paresthesia-independent 10 kHz spinal cord stimulation (HF10 therapy) and traditional paresthesia-based low-frequency (~50 Hz) SCS. Correlations to functional outcomes were explored.
Results: At 12 months, 68.5% of HF10 therapy patients achieved back pain remission and 67.4% achieved leg pain remission compared to 35.8% and 42.5% respectively for traditional SCS patients (p<0.001 for both). Patients achieving remission averaged VAS scores of 1.2±0.7 for back pain and 0.9±0.8 for leg pain.
Higher Oswestry Disability Index (ODI) scores were associated with higher back pain scores (r=0.608, p<0.001). Pain scores were negatively correlated with both SF-12 Physical Component Summary (PCS) and Mental Component Summary (MCS) subscales (r=-0.477 PCS, -0.326 MCS, p<0.001 for both). Classification of subjects as remitters or non-remitters was highly correlated with ODI (p<0.001) and SF-12 measures (p<0.001).
Conclusions: Remission is henceforth introduced to interventional pain management. In the SENZA-RCT study, two-thirds of the HF10 therapy patient achieved durable pain remission. Remission status is directly correlated with improved function. We propose "remission in a majority of patients" as a benchmark for pain management therapies.
Patient Care: The introduction of remission from chronic pain provides pain physicians with a new perspective when evaluating pain therapies.
Learning Objectives: 1. Introduce the concept of remission to interventional pain management.
2. Provide comparative remission rates for back and leg pain.
3. Correlate remission status to functional outcomes.