High-Frequency Spinal Cord Stimulation Therapy in Failed Back Surgery Syndrome Patientswith Predominant Back PainAdnan Al-Kaisy1, Jean-Pierre Van Buyten2, Stefano Palmisani1, Thomas Smith1, Iris Smet2 1St Thomas' hospital, London, United Kingdom, 2AZ Nikolaas, St Niklaas, Belgium

Study supported by grant from Nevro Corp (Menlo Park, CA)

CAUTION – Nevro’s Senza™ system is an investigational device limited by Federal (USA) law to investigational use. The device is approved for use in the European Union.

2Disclosure

5%

15%

6%

8%

9%

8%

14%

24%

18%16%

Most common locations of chronic pain

FBSS:

Each year, more than 1 million spinal surgeries are performed in the US with 400,000 cases being instrumented. 1

Roughly half of these are in the lumbosacral area. 2

Despite surgery, approximately 30% of these patients fail to improve, as shown by persistent back pain. 2

SCS:

Traditional SCS is a well-accepted option for Failed Back Surgery Syndrome (FBSS) patients with predominantly neuropathic leg pain. 1, 2

However, providing adequate and sustained back pain relief for patients with predominant back pain remains more challenging. 1, 2

Introduction

1 Frey, Manchikanti, Benyamin, et al. Spinal Cord Stimulation for Patients with Back Surgery Syndrome: A Systematic Review. Pain Physician. 2009; 12:379-397.2 Van Buyten JP, Linderoth B. “The Failed Back Surgery Syndrome”: Definition and therapeutic algorithms: An Update. Eur J of Pain Suppl. 2010;4:273-286.

High-Frequency SCS

Senza High-Frequency SCS system is a novel SCS system allows pulse rate up to 10 kHz.

Surgical technique similar to traditional SCS, however, a useful difference:

• Traditional SCS requires intraoperative paresthesia mapping

• Potentially uncomfortable for patient

• Can lead to wide range in procedure times

• HF-SCS lead positioning is more efficient:

• No paresthesia mapping needed

• Anatomically positioned

• Overlapping leads along midline

Shorter, more predictable procedure times

High-Frequency SCS & FBSS

Senza was evaluated for use in the treatment of chronic pain in a prospective, open label study. 3

• The study trialed 83 patients with or without prior surgery

• The study demonstrated the safety and efficacy of the novel therapy

• A subset analysis was conducted for the FBSS subset

• This subset includes 67 patients

• The patients were followed-up to 12 months

3 Van Buyten et al, High-Frequency Spinal Cord Stimulation for the Treatment of Chronic Back Pain Patients: Results of a Prospective Multicenter European Clinical Study. Neuromodulation. Accepted for publication

Baseline Demographics

Baseline Demographics(n=67)

Mean age in years 49.6 ± 9.5

Gender 54% Female

Mean years since back pain diagnosis

10

Predominant back pain 91%

Failed traditional SCS 18%

VAS Back (SD) 8.4 ( 1.2)

VAS Leg (SD) 5.4 ( 3.2)

Mean # of prior surgeries (range)

2 (1-5)

History of back surgery:spinal fusiondiscectomy laminectomy disc replacement

52%42%40%13%

57/66 patients (86%) had successful trial (> 50% pain relief) and went to permanent implant.

Notable results given significant number of difficult-to-treat patients:

•91% of FBSS cohort had predominant back pain, which doesn’t respond well to traditional SCS

•18 % of FBSS cohort previously failed traditional SCS

Trial Results

Note: 1 patient did not complete the trial

Pain Relief at 12 Months

N=57 N=57

Average Visual Analog Scale (VAS) for Pain(mean + SEM)

N=54

p < 0.001 p < 0.001

Note: Subjects who have successfully passed the trial and received permanent implant

Significant and sustained back pain & leg pain relief despite difficult-to-treat population.

70% of the patients had ≥ 50% backpain relief at 12 months.

Improved Function at 12 Months

N=56 N=56

Average Oswestry Disability Index(mean + SEM)

Lowdisability

Severe disability

p < 0.001

N=53

p < 0.001

Sustained reduction in disabilities.

15 point decrease in ODI at 12 months.

Device related Serious Adverse Events were consistent with standard SCS practice:

•There were no therapy-related neurological findings.

•No device had to be explanted due to battery life issues.

Excellent Safety Profile

SAE Number of Events

Pocket Pain 4

Wound Infection 3

Lead Migration 2

Loss of Pain Relief 1

Suboptimal Lead Placement 1

Despite advances in traditional SCS (i.e. transverse tripole, triangular stimulation, etc), providing relief to FBSS patients with predominant axial low back pain remains very difficult.

This 67 patient analysis of High-Frequency SCS on FBSS patients shows:

•High trial success rate despite difficult to treat patients (91% of the cohort had predominant back pain)

• 86% trial phase success rate

•Significant and sustained relief for both back pain and leg pain

• 70% responder rate at 12 months

• Sizeable and durable improvement in function

• 15 point reduction in ODI at 12 months

•HF-SCS should be considered as a leading therapeutic option for FBSS patients (even those with predominant back pain)

Summary & Conclusions

CAUTION – Nevro’s Senza™ system is an investigational device limited by Federal (USA) law to investigational use. The device is approved for use in the European Union.