Multi-waveform Spinal Cord Stimulation with High Frequency Electromagnetic Coupled (HF-EMC) Powered Implanted Electrode Array and Receiver for the Treatment of Chronic Back and Leg Pain (SURF Study).

BACKGROUND: Novel externally powered spinal cord stimulation technology can be fully implanted when trialing the effectiveness of the therapy, since no percutaneous leads are needed, and the trial period lasted 30 days. Multiple tests of different stimulation modalities and parameters are possible, thus improving the chances that the therapy will lead to effective pain reduction. OBJECTIVES: The objective of this study was to analyze the effectiveness of the Freedom Spinal Cord Stimulator System (Stimwave LLC, Pompano Beach, FL) for the treatment of failed back surgery syndrome due to postlaminectomy syndrome utilizing multiple waveforms. STUDY DESIGN: This was a prospective, single cohort study. Patients were enrolled and implanted with up to 2 permanent, 8-contact electrode arrays with receiver, controlled regularly during 6 months of follow-up after a one month trial period. Pain and overall improvement were evaluated at 3 months and 6 months following an initial one-month implanted trial period. SETTINGS: A variety of frequency stimulation waveforms (tonic as well as subthreshold) at frequencies of 10 Hz to 1500 Hz* and 50 to 800 µs pulse width, were provided. (*Note: While 1500 Hz was utilized in the study, Stimwave Technologies is currently only permitted to provide spinal cord stimulation therapy at frequencies below 1500 Hz, therefore pulse rates used in this study are not commercially available on Stimwave Technologies' products). METHODS: Endpoints evaluated included the Visual Analog Scale (VAS) for pain intensity, Oswestry Disability Index (ODI) for functionality, Patient Global Impression of Change (PGIC) for overall health improvement, and quality of life as measured by the European Quality of Life 5 Dimension questionnaire (EQ-5D-5L). RESULTS: Thirty-nine patients completed the study. At 6 months, the responder rate (? 50% reduction VAS for back pain) was 33/39 = 85%. Mean VAS for back pain decreased 62%. The mean ODI decreased 46% from 54 to 29.2, indicating a reduction from severe to moderate disability. The median satisfaction as measured with the PGIC was 6 out of 7. The mean EQ-5D-5L utility score increased from 0.54 to 0.75. At the 6-months endpoint, 44% (17/39) of patients preferred tonic stimulation with a back pain per protocol responder rate of 82%; 41% (16/39) preferred surge with a responder rate of 56%; and 15% (6/39) preferred high density, with a responder rate of 83%. Fifteen patients reported 28 adverse events. Migration of the electrode array (n = 10) was the adverse event most reported. Two serious adverse events related to infection were reported. LIMITATIONS: This study had several limitations. Trial failures were excluded from the analysis, there was a small sample size, and there was a lack of blinding due to the suprathreshold nature of tonic stimulation. CONCLUSION: The study demonstrates that spinal cord stimulation with multiple stimulation patterns demonstrates clinical and functional efficacy when using an externally powered stimulation system.

Redefining Spinal Cord Stimulation "Trials": A Randomized Controlled Trial Using Single-Stage Wireless Permanent Implantable Devices.

BACKGROUND: "Traditional" spinal cord stimulation (SCS) trials with percutaneous electrodes externalized to a pulse generator (PG) are typically limited in duration due to risk of infection. Newer miniaturized wireless SCS technology eliminates the percutaneous extension (as well as PGs implanted for chronic use), thus facilitating a single-stage implantation after which the device can remain indefinitely. OBJECTIVE: To evaluate fully implanted wireless SCS devices during a 30-day screening trial in subjects with chronic low back pain and leg pain and a history of lumbosacral spine surgery. METHODS: In a randomized controlled trial of single-stage wireless SCS using a wireless percutaneous system, 99 subjects received either 10 kHz high frequency stimulation (HFS) or lower frequency stimulation (LFS) below 1500 Hz (Bolash R, Creamer M, Rauck R, et al. Wireless high frequency spinal cord stimulation (10 kHz) compared to multi-waveform low frequency spinal cord stimulation in the management of chronic pain in failed back surgery syndrome subjects: preliminary results of a multicenter, prospective, randomized controlled study. Pain Med 2019, https://doi.org/10.1093/pm/pnz019). In this report, we assess the 30-day trial success rate (≥50% pain relief from baseline) and complications. RESULTS: The overall trial success rate was 88% (87/99): 92% (46/50) for HFS and 84% (41/49) for LFS (NS). The trial success rate in the 64 subjects with predominant low back pain was 92% (59/64) vs. 80% (28/35) in those with leg pain ≥ low back pain (NS). During the screening trial, one infection occurred (1%) and one subject withdrew and was explanted (1%). Electrode migrations were seen on routine follow-up x-rays in 10 cases (10%). CONCLUSION: Using wireless SCS devices that allow for an extended trial period and evaluation of various waveforms, we observed a high rate trial success rate with both HFS and LFS waveforms, with minimal incidence of infection. Long-term follow-up will address the cost-effectiveness and morbidity associated with this technology, which facilitates single-stage treatment.

Wireless High-Frequency Spinal Cord Stimulation (10 kHz) Compared with Multiwaveform Low-Frequency Spinal Cord Stimulation in the Management of Chronic Pain in Failed Back Surgery Syndrome Subjects: Preliminary Results of a Multicenter, Prospective Randomized Controlled Study.

BACKGROUND: This study aimed to evaluate the wireless Freedom Spinal Cord Stimulator (WSCS) System for the treatment of chronic back and/or leg pain associated with failed back surgery syndrome (FBSS) refractory to standard medical treatment utilizing 10-kHz stimulation (high-frequency [HF]) in comparison with 10-1,500-Hz stimulation (low-frequency [LF]) waveforms. METHODS: Ninety-nine subjects were randomized in a 1:1 ratio to receive either HF or LF stimulation waveforms utilizing the same Freedom WSCS System. All subjects were implanted with two 8-electrode arrays in the exact same anatomical positions within the dorsal epidural spinal column, with the top electrode positioned at the T8 and T9 vertebrae levels, respectively, and the wireless receiver placed under the skin in a subcutaneous pocket. RESULTS: Seventy-two (HF: N = 38; LF: N = 34) subjects had completed the six-month follow-up after an initial 30-day trial period at the time of this report. For both the HF and LF arms, mean visual analog scale (VAS) scores for back and leg pain decreased significantly: 77% and 76%, respectively, for the HF arm and 64% and 64%, respectively, for the LF arm. In addition, most subjects experienced significant improvements in VAS, Oswestry Disability Index, European Quality of Life 5 Dimension questionnaire, Patient Global Impression of Change, and sleep duration. CONCLUSIONS: These preliminary results demonstrate that WSCS devices can reduce FBSS chronic pain substantially with both LF and HF stimulation waveforms over a seven-month period (30-day trial period and six-month post-trial evaluation).

High-Frequency Supraorbital Nerve Stimulation With a Novel Wireless Minimally Invasive Device for Post-Traumatic Neuralgia: A Case Report.

BACKGROUND: Post-traumatic neuropathic pain in the head and face is a condition that is often refractory to medical management. Peripheral nerve stimulation (PNS) can be an effective treatment. Successful implantation of a novel minimally invasive wireless device is reported here. OBJECTIVE: To assess analgesic effects of a minimally invasive wireless PNS device in the treatment of post-traumatic supraorbital neuralgia (SON). CASE SUMMARY: The patient presented with SON following multiple post-traumatic cranioplasty surgeries, which were complicated by infections. Medical and interventional management failed, and the patient reported a numeric rating scale (NRS) pain score of 8 out of 10. Two octopolar implantable neural stimulators (INSs) (StimRelieve LLC, Pompano Beach, FL, U.S.A.) were implanted with a minimally invasive, percutaneous technique to stimulate the supraorbital nerves. Stimulation parameters were set at a frequency of 10 kHz and a pulse width of 30 microseconds. RESULTS: At 12- and 24-month follow-up evaluations, the patient's NRS score was only 2 out of 10, and the patient occasionally required 1 g of paracetamol to control the pain. Stimulation was reported to be paresthesia free. There were no adverse events related to the procedure or the treatment until today. CONCLUSIONS: High-frequency stimulation with an external pulse generator and minimally invasive, percutaneous, and bilateral placement of 2 passive INSs on the supraorbital nerves resulted in a significant pain relief in this patient with post-traumatic SON. The device was safe and effective, and the cosmesis was satisfactory.

A Novel Minimally Invasive Wireless Technology for Neuromodulation via Percutaneous Intercostal Nerve Stimulation for Post-Herpetic Neuralgia: A Case Report with Short-Term Follow-up.

BACKGROUND: Peripheral nerve stimulation of primary afferent neurons provides control of localized chronic pain. This technique applies permanent electrical stimulation at the target area via a minimally invasive, subcutaneous placement of an electrode. OBJECTIVE: To assess the analgesic effects of minimally invasive wireless neuromodulation in the treatment of chronic intractable pain secondary to post-herpetic neuralgia. CASE SUMMARY: A 78-year-old man presented with severe intractable post-herpetic neuralgic pain. He was known to have non-Hodgkin's lymphoma under remission following treatment with chemotherapy and stem cell transplantation, twice. He also developed steroid-induced diabetes mellitus during this treatment. In view of his compromised immune status, he was deemed a suitable candidate for our minimally invasive neuromodulation technology. Two subcutaneous electrodes were placed on the right-hand side of the trunk, 10 cm medial and parallel to the spinous process at the level of T7-T8 under fluoroscopic guidance along the T7 intercostal nerve. The external transmitter was worn with a belt over a single layer of clothing and used to transmit power to the stimulator. The entire procedure required only a small incision for the introduction of the electrode placement. RESULTS: After an uneventful procedure, the pain score decreased from 8 to 3, with a reduction in pain medication. The EuroQol Five Dimensions Questionnaire scores were 0.102 before the trial, 0.630 at 1 month, and 0.576 at 3 months. CONCLUSIONS: Subcutaneous placement of electrodes with our minimally invasive technique and wireless neuromodulation technology was safe and effective. Significant improvements in pain relief ensued, and no further adverse events had been reported at the end of 3 months' follow-up.

Wireless Neuromodulation for Chronic Back Pain: Delivery of High-Frequency Dorsal Root Ganglion Stimulation by a Minimally Invasive Technique.

OBJECTIVE: To evaluate the analgesic effect of a dorsal root ganglion (DRG) stimulation technology utilizing high-frequency pulse rates to treat intractable chronic back and leg pain. METHODS: This case study presents the outcomes, with a novel, wireless, minimally invasive miniature neurostimulator system in a case of chronic back pain. The subject was implanted bilaterally with a Freedom 4A quadripolar electrode array at the L2 dorsal root ganglion. Stimulation was applied using 10 kHz pulse rate and 30 µs pulse width. A VAS pain-rating scale, Oswestry Disability Index (ODI), EQ-5D-5L Quality of Life Questionnaire 5 dimensions, and Patients' Global Impression of Change (PGIC) scale were evaluated at 12 weeks and 6 months post implantation. RESULTS: VAS pain scores for back pain reduced from 91 to 31 mms and 80 to 35 mms for leg pain. Additionally, while stimulation remained paresthesia-free, there were a marked decrease in pain medications and an increase in quality of life. Also, an increase in functionality from crippled to moderate was reported. There were no adverse reactions related to the procedure or device. CONCLUSION: The minimally invasive, wireless approach to deliver high-frequency, paresthesia-free DRG stimulation for treatment of chronic back and leg pain associated with FBSS was effective and encouraging.

A novel miniature, wireless neurostimulator in the management of chronic craniofacial pain: Preliminary results from a prospective pilot study.

OBJECTIVE: To report a novel wireless neuromodulation system for treatment of refractory craniofacial pain. BACKGROUND: Previous studies utilizing peripheral nerve stimulation (PNS) of the occipital and trigeminal nerves reported positive outcomes for alleviating neuropathic pain localized to the craniofacial and occipital areas. However several technological limitations and cosmetic concerns inhibited a more widespread acceptance and use of neuromodulation. Also, a relatively high incidence of adverse events like electrode erosions, dislocation, wire fracture and/or infection at the surgical site mandates a change in our approach to neuromodulation technology and implant techniques in the craniofacial region. METHODS: We report a novel approach for the management of craniofacial pain with a wirelessly powered, minimally invasive PNS system. The system is percutaneously implanted and placed subcutaneously adjacent to affected facial nerves via visual guidance by the clinician. In this feasibility study, pilot evidence was gathered in a cohort of ten subjects suffering from a combination of chronic headaches, facial pain for at least 15 days per month and for at least 4h/day. RESULTS: At four weeks post-implant follow up, all patients reported sustained pain relief of the primary pain area. Electrode location and total number of electrodes used per subject varied across the cohort. The average pain reduction using the visual analog scale was ≥82%. The procedure had no adverse events or side effects. CONCLUSION: Percutaneous placement of a wireless neurostimulation device directly adjacent to affected craniofacial nerve(s) is a minimally invasive and reversible method of pain control in patients with craniofacial pain refractory to conventional medical managements. Preliminary results are encouraging and further larger scale studies are required for improved applications.