1. Successful Treatment of Low Back Pain with a Novel Neuromodulation Device Iris Smet, MD 1 Jean-Pierre Van Buyten, MD 1 Adnan Al-Kaisy MB ChB FRCA 2 1 AZ Nikolaas Hospital, Belgium 2 Guy’s and St. Thomas’ Hospital, United Kingdom

2. Conflict of Interest Primary Investigator; study sponsored by Nevro Corporation, Menlo Park, CA 2

3. Key Challenges in SCS Treating back pain remains a challenge –Leg pain component only –PROCESS Study - Kumar, 2006 Uncomfortable stimulation –Patients experience “shocking” sensation –Stimulation/posture adjustments required to decrease uncomfortable stimulation –Kuechmann, 2009 Opioids remain part of treatment regimen –Side-effects outweigh benefits –Van Buyten and Linderoth, 2010 Opportunity for SCS in treating back pain 3

4. Study Overview Purpose: Demonstrate effectiveness in chronic back and/or leg pain patients –First permanent implant study with this novel SCS Design: Prospective, Observational Study Population: Back pain score > 5 out of 10 on VAS Key Outcomes Measurements –Pain relief using Visual Analog Scale (VAS) –Functional improvements using Oswestry Disability Index –Opioid usage –Incidence of SCS-induced movement-dependent discomfort 4

5. Study Flow (St. Nikolaas Site) Up to 50 patients will be trialed –Study is ongoing (interim results shown) Permanent percutaneous lead trial (Anchored & tunneled) –Duration 4 weeks +/- 2 weeks Anatomical not physiological lead placement Adverse Events –Infection during trial phase (4), lead migration (2), thrombosis (1), edema (1), pocket pain (2), sensation change (1), skin irritation (2), infection during perm (2) 5 IPG Implanted 1 Month 3 Months 6 Months Successful Trials n=38 (90%) Trialed n=42 Failed Trials n=4 Ongoing trial. Interim results shown. 21 patients have passed 6 month visit. Other patients have yet to reach 6 month visit.

6. Patient Population 6 42 Patients Trialed to-date; Mean age is 49 ± 8.1 years, 76% are females Patients w/ no prior spine surgery (N=9) FBSS Patients (N=33) Predominant Back Pain Patients (N=36) Predominant Leg pain patients (N=6) 21% 79% 14% 86% Pain Type Surgical History Refractory to conservative treatments (e.g., radiofrequency) with no long-term benefit Considered not to be surgical candidates. Neurosurgeon evaluated for mechanical instability and referred non-surgical candidates to the pain clinic.

7. Back and Leg Pain Reduction 7 N=29N=28N=21 Note*: Baseline VAS shown above is from patients who passed 3 month visit. One patient missed 3 month visit, but came for 6 month visit. Average Visual Analog Scale (VAS) for Pain (mean +/- SEM) Back pain VAS: p-value < 0.001 Leg pain VAS: p-value < 0.001 Back pain VAS: p-value < 0.001 Leg pain VAS: p-value < 0.001

8. No Uncomfortable Stimulation No uncomfortable stimulation with position change No adjustment of stimulation required with postural change *Kuechmann, 2009 8 Uncomfortable Stimulation due to Position Change % of Patients Adjust Stimulation Before or After Position Change % of Patients

9. Reduction in Opioid Use 9 N=21 Only 14% of patients are using opioids at 6 months N=21 Only 3 mg of morphine per patient at 6 months

10. Improvement in Function and Sleep 10 9 point reduction was observed in other SCS studies (1) Average Oswestry Disability Index (mean +/- SEM) Low disability Severe disability N=29 p-value < 0.001 Functional Improvement: 21 point reduction at 6 months Sleep Improvement: 87% reduction in sleep disturbances (1) Other SCS study results: 9 point reduction (Taylor, 2005) N=28N=21 Number of Sleep Disturbances per Night (mean +/- SEM) N=21 p-value < 0.001 Note*: Baseline ODI shown above is from patients who passed 3 month visit. One patient missed 3 month visit, but came for 6 month visit.

11. Summary Sustained back & leg pain relief at 6 months* Significant elimination and reduction of opioid usage* Improved patient functionality and sleep* No sensation of paresthesia No uncomfortable stimulation Proportion and type of adverse events are consistent with other SCS studies conducted 11 Note*: In comparison to baseline

12. Thank you! 12