Senza SCS System Approved
The Senza spinal cord stimulation (SCS) system (Senza System, Nevro) has been approved “to aid in the management of chronic intractable pain of the trunk and/or limbs, including pain associated with failed back surgery syndrome, low back pain, and leg pain,” according to a press release from the US Food and Drug Administration.
"The FDA has approved several other totally implanted spinal cord stimulators for pain reduction, but this system is unique because it delivers a high frequency output of 10 kHz that does not cause paresthesia, or tingling sensation, in patients," said William Maisel, MD, MPH, acting director of the Office of Device Evaluation at the FDA's Center for Devices and Radiological Health. "Since some patients don't like the paresthesia associated with traditional SCS, this device offers another treatment option."
Although the exact mechanism for pain control from SCS is not entirely understood, it is believed to result from direct or facilitated inhibition of pain transmission. Table 1 lists the five mechanistic theories for why SCS works.
A spinal cord stimulator neuromodulation system should be considered for patients who have failed all reasonable conservative care including appropriate diagnostic, therapeutic, and rehabilitative techniques, and have been given a reasonable period of time to recover from the condition. A reasonable time period is at least 6 to 12 months of conservative, pain-relieving, minimally invasive treatments, and/or failure of surgical treatments, with persistent extremity pain greater than axial spine pain.
Approval was based on a clinical study including 198 patients with chronic intractable pain of the trunk and/or limbs who were randomized to either the Senza System test group or to a control group comprising 97 subjects treated with another FDA-approved device that delivers stimulation in the 2–1200 Hz frequency range that produced paresthesia.
Of patients receiving treatment with the Senza System, 75% achieved a 50% reduction in pain from baseline at 3 months, and an approximately 55% reduction at 12 months.
There were no stimulation-related neurological deficits, such as weakness in the limbs or tremors, observed for either treatment group. The most common adverse events associated with treatment were pain at the implant site and dislocation of the device lead under the skin.