David Pang

The Use of 10‐Kilohertz Spinal Cord Stimulation in a Cohort of Patients With Chronic Neuropathic Limb Pain Refractory to Medical Management

It is the purpose of this study to document our experience with the use of a 10‐kHz high‐frequency spinal cord stimulation (SCS) device for the relief of neuropathic pain of the upper and lower limbs.

Subcutaneous Target Stimulation–Peripheral Subcutaneous Field Stimulation in the Treatment of Refractory Angina: Preliminary Case Reports

Abstract:  Spinal cord stimulation is now established as an effective treatment for refractory angina. We present the use of an alternative approach to neuromodulation of anginal pain using subcutaneous leads placed at the site of pain. In this case series, five patients with refractory angina received successful treatment with subcutaneous target stimulation–peripheral subcutaneous field stimulation. This technique was able to provide good analgesia in two patients that had had poor pain relief from existing spinal cord stimulators. All five patients achieved significant pain relief with a reduction in symptoms and a decrease in the use of pain medication.

10 kHz High-Frequency Spinal Cord Stimulation for Chronic Axial Low Back Pain in Patients With No History of Spinal Surgery: A Preliminary, Prospective, Open Label and Proof-of-Concept Study.

To explore the effectiveness of 10 kHz high frequency spinal cord stimulation (HF10 therapy) treatment of chronic low back pain in patients who have not had spinal surgery.

Long-Term Improvements in Chronic Axial Low Back Pain Patients Without Previous Spinal Surgery: A Cohort Analysis of 10-kHz High-Frequency Spinal Cord Stimulation over 36 Months

Objective This prospective, open-label study was designed to evaluate the long-term effectiveness of 10-kHz high-frequency spinal cord stimulation (SCS) in the treatment of chronic axial low back pain with no history of spinal surgery. Methods Patients with chronic low back pain without previous spinal surgery underwent assessment by a multidisciplinary pain and surgical team to confirm eligibility. After a successful temporary trial of 10-kHz HF-SCS therapy, defined by ≥50% back pain reduction, enrolled subjects underwent permanent system implantation and were followed up for 36 months. Outcome measures consisted of a 100-mm visual analog scale (VAS) for pain intensity, the Oswestry Disability Index (ODI), and a standard measure of health-related quality of life. Results Twenty-one patients satisfied the inclusion/exclusion criteria. Following a temporary trial, 20 of 21 (95%) subjects were implanted with a pulse generator, and 17 of 20 reached the 36-month time point. From baseline to 36 months, the average VAS pain intensity decreased from 79 ± 12 mm to 10 ± 12 mm, the average ODI score decreased from 53 ± 13 to 19.8 ± 13, and use of opioids decreased from 18 subjects to two subjects. One subject was deceased, unrelated to the study, one subject was explanted due to loss of effectiveness, and one subject was lost to follow-up. Conclusions These results suggest that 10-kHz high-frequency SCS may provide significant, long-term back pain relief, improvement in disability and quality of life, and reduction in opioids for nonsurgical refractory back pain.

Current experience of spinal neuromodulation in chronic pain: Is there a role in children and young people?

INTRODUCTION Chronic pain in children has been an under-recognized problem compared to adult pain. The aim of management is to help children and their families cope with the symptoms rather than a cure. Current medical treatments to reduce pain intensity are often short lived, poorly tolerated or ineffective. RESULTS The use of electrical stimulation to treat pain is the current basis of modern Neuromodulation at the spinal cord and has been well established as spinal cord stimulation in adult practice. This involves placement of an epidural electrode connected to a subcutaneous implanted pulse generator. The electrode generates an electrical field at the dorsal columns of the spinal cord that inhibits pain pathways. Randomised controlled trials have demonstrated efficacy in neuropathic pain states such as the failed back surgery syndrome and complex regional pain syndrome. CONCLUSION Despite its initial expense, Spinal cord stimulation is a cost effective therapy in the long term and has the advantages of being a minimally invasive therapy and reversible.

Targeting and fielding: not the same!

Dear Sir, We would like to congratulate Dr Levy on his excellent editorial and in particular for the comprehensive discussion of the terminology regarding peripheral neurostimulation (1). Peripheral neurostimulation has been in the surgical domain since its conception in 1965 with the exception of an initial application to the infra-orbital nerves by Wall and Sweet (2). This was facilitated by the gate theory of pain proposed by Melzack and Wall (2) and the first surgical peripheral implant took place in 1967 (3). The initial period of exclusively surgical implantations lasted until 1999 when Weiner percutaneously introduced a needle in the proximity of the greater occipital nerve (4). This work opened the gate for the further expansion of percutaneous techniques. In the last decade new techniques and targets have been successfully developed (4–25). However, the present terminology of percutaneous neurostimulation is unclear and frequently confusing. Regarding this issue, we have to take a strong intellectual analysis to make it sound and well designed for the future. Terminology should be clear, well understood by implanters, other pain professionals and by our patients. It must be accurate and precise in its wording so that ambiguity is avoided. Although the term peripheral stimulation is undisputable, its various approaches have generated additional complexity and has led to a number of different and potentially confusing terminologies. (please edit previous sentencenot clear) For example, we should be able to differentiate “nerve” or “plexus” stimulation and stimulation of other structures. Therefore an addition of “nerve” to terminology as suggested (26) is a logical step forward to name this type of stimulation Peripheral Nerve Stimulation (PNS). An addition or exchange of the word “plexus” to achieve more specificity in our view will not contribute further in clarifying future terminology. Now as the next step, we should analyse if different terminology is required or needed to show differences between surgical and nonsurgical procedures. In the editorial, Dr Levy supported a universal approach with no distinction between the two types of implants. We would like to take this argument in favour of a distinction between surgical and non-surgical implants. We feel strongly that a future terminology should distinguish clearly between the two approaches, as percutaneous approaches in spinal cord stimulation have become dominant. The same is likely to happen in peripheral stimulation. With gradually improved technology, simpler techniques leading to lower complication rates, surgical peripheral implants will become less common, like that of surgical spinal cord implants. Taking an example of other surgical procedures where there is distinct information about the type of surgery is the use of laparoscopic, minimally invasive approaches compared to open surgery. The word “laparoscopic” is always used in the surgical description as the outcomes can be dramatically different. So, our view is that we should consider adding a word to make the distinction between surgical and non-surgical approaches. “Percutaneous” is a good choice for example: “peripheral percutaneous nerve stimulation” or “peripheral surgical nerve stimulation”. “Subcutaneous” is less precise as it describes a position and not a method. This leads us to the question of what terminology should be used for stimulation in non-dermatological distributions. Originally in this technique, stimulation was delivered at the epicentre of pain in the subcutaneous tissue to optimise coverage and to affect as large an area as possible. This was termed “targeted stimulation” as the critical part of the technique involved placement of the electrodes at a precise point and depth, hence the word “target”. The aim is to target the point with the highest intensity of pain and not to achieve a uniform area or field of stimulation. This point is crucial as misinterpretation of the technique will lead to failure. A recent article in emphasising the importance of the position of the electrode depth further adds weight to the importance of electrode position (27). If it were field stimulation then the electrode position would not be as critical and it would not be possible to treat patients with pain in large areas. With incorrect terminology we risk the techniques becoming incorrectly applied with predictable poor results and becoming discredited. We must learn the lessons from the use and misuse of electrical stimulation in the 1970s. In our view, we should approach this issue of terminology with an open heart and mind and not to enter any conclusions without exploring all intellectual options. We hope our voice will contribute to this important discussion for the future of peripheral stimulation.

Prospective, Randomized, Sham-Control, Double Blind, Crossover Trial of Subthreshold Spinal Cord Stimulation at Various Kilohertz Frequencies in Subjects Suffering From Failed Back Surgery Syndrome (SCS Frequency Study): CROSSOVER TRIAL OF SCS At VARIOUS kHz FREQUENCIES IN FBSS

The increasing use of high frequency paresthesia‐free spinal cord stimulation has been associated with improved outcomes in the therapy of neuropathic pain. What is unknown is the effect of varying frequency on pain relief and the placebo effect.

High frequency cervical spinal cord stimulation in the treatment of refractory trigeminal neuralgia

There are limited options to treat trigeminal neuralgia once medical, surgical and interventional approaches have been exhausted. Neuromodulation is a treatment modality that shows promise and so far case reports have used peripheral approaches to the trigeminal ganglion and its branches. We describe the use of high frequency spinal cord stimulation at the cervical spine as a novel approach to management of refractory trigeminal neuralgia.

Peripheral Neuromodulation for Angina: Gathering Momentum

Dear Sir, We read with great interest Dr Buiten and colleagues’ report, together with the reviewer’s comments on the application of peripheral subcutaneous stimulation for the treatment of refractory angina (1). It is extremely satisfying for us that the results of this study have fully supported our previous initial investigations, observations, and studies (2–7). It is worth noting that in two of our reported patients, SCS wasn’t very effective, contrary to excellent angina control by peripheral stimulation. The presence of an implanted device such as an existing spinal cord stimulator also did not cause a problem in our patient with syndrome X and we were able to accommodate both spinal and peripheral stimulation strategies simultaneously. Of note, our first patient that was implanted with peripheral subcutaneous leads in September 2004 still benefits from peripheral stimulation (7). An unresolved issue is, of course, terminology for this very promising modality. Various terms are in use, ranging from subcutaneous target stimulation (6, 8), subcutaneous peripheral field stimulation (9), and subcutaneous electrical nerve stimulation (10). In an excellent recent editorial, Robert Levy proposed the introduction of a further logical order to the terminology of peripheral stimulation (11). As suggested previously, an urgent consensus meeting with a wide range of representatives in the field of peripheral stimulation is required (12). We would like to stress that despite the simplicity of the technique, routine screening assessment process should be always rigorously applied. This resurgence in peripheral approaches to neuromodulation has given clinicians more options in its use for managing chronic pain conditions. The peripheral stimulation technique for the treatment of angina is much simpler than the well established SCS with a potentially comparable effectiveness and reduced complication rate. In the largest case series, the complication rate was lower than seen for conventional spinal cord stimulation and it was encouraging to see that effectiveness was observed for many years (13). Another long term retrospective study also demonstrated that effectiveness could be sustained (5). However, without high quality randomized studies, these innovative methods risk being lost as regulatory bodies demand greater levels of evidence than currently exist. Lessons must be learned from the fall in the use of neuromodulation in the 1970s due to a lack of effectiveness and safety studies (14). Yours sincerely,