Electrical Stimulation for the Treatment of Back Pain Using Peripheral Nerve Stimulation (PNS)

All subjects were asked to complete daily diaries to record their average pain intensity on each day of a 7-day period. The pain intensity question was excerpted from the Brief Pain Inventory-Short Form Question 5 (BPI-5). The BPI-5 uses an 11-point numerical rating scale where 0 represents "No Pain" and 10 represents "Pain as bad as you can imagine." For each subject, the mean score for the baseline and end of treatment (EOT) diary periods were calculated and percent reduction was determined. Subjects that achieved ≥30% reduction in pain, were considered successful.

At each study visit following the baseline assessment at Visit 1, subjects were questioned if any changes in their medical status or condition has occurred since their previous visit. If the subject experienced a change that was an adverse event, an Adverse Event Form was completed by the site. The number of subjects that experienced at least one study-related adverse event is reported here.

All subjects were asked to complete daily diaries to record their worst pain intensity on each day of a 7-day period. The pain intensity question was excerpted from the Brief Pain Inventory-Short Form Question 3 (BPI-3). The BPI-3 uses an 11-point numerical rating scale where 0 represents "No Pain" and 10 represents "Pain as bad as you can imagine." For each subject, the mean score for the baseline and end of treatment (EOT) diary periods were calculated. The mean score across all subjects for each time point is reported.

The Oswestry Disability Index (ODI) is a widely used assessment designed to measure the degree of disability in people with low back pain. This validated questionnaire includes topics concerning the intensity of pain, the subject's ability to perform normal daily activities such as personal care, walking, sitting, or standing, and how pain affects the subject's sex life, social life, and travel. The scale ranges from 0-100 and higher scores indicate greater disability due to low back pain. The mean score across all subjects at baseline and end of treatment (EOT) is reported here.

The RAND 36-Item Short Form Health Survey is a widely accepted form used to quantify quality of life. The survey consists of 8 categories with a total of 36 questions regarding the subject's general health and activities. The survey assesses physical and emotional problems associated with pain during the past 4 weeks. Each category is scored on a 0-100 scale, where a higher score indicates a more favorable health state. The score for each category was calculated at baseline and End of Treatment (EOT) for each subject. The change in each category score from Baseline to EOT was then calculated for each subject (with a positive change indicating an increase in health-related quality of life). The mean and standard deviation of the subjects' changes in each category are presented below.

The Beck Depression Inventory (BDI-II) is a validated, 21-question survey used to measure depression severity. Questions are rated on a scale from 0 to 3, and the scores from each question are totaled to provide an overall score ranging between 0 to 63. Scores from 0-13 indicate minimal depression, 14-19 mild depression, 20-28 moderate depression, and 29-63 indicates severe depression. The average total scores across subjects were calculated at baseline and end of treatment (EOT).

The Patient Global Impression of Change (PGIC) asks subjects to rate their improvement with treatment on a 7-point scale where 1 represents "very much worse" and 7 represents "very much improved" as compared to before stimulation treatment. The subjects combine all the components of their experience into one overall score. The number of participants with each rating after 8 weeks of treatment is reported here.

Question 9 of the Brief Pain Inventory-Short Form (BPI-9) is a 7-part question that assesses the level of interference that subjects experience in their daily lives due to pain. The 7 categories are general activity, mood, walking ability, normal work, relations with other people, sleep, and enjoyment of life. Subjects were asked to rate how much their low back pain interferes with each aspect on an 11-point numerical scale where 0 represents "Does Not Interfere" and 10 represents "Completely Interferes." The average of these 7 scores was calculated for each subject. The mean was taken across subjects for each time point.