Effect of Burst Stimulation Evaluated in Patients Familiar With Spinal Cord Stimulation.

OBJECTIVE: Spinal cord stimulation (SCS) is used for treating intractable neuropathic pain. It has been suggested that burst SCS (five pulses at 500 Hz, delivered 40 times per second) suppresses neuropathic pain at least as well as conventional tonic SCS, but without evoking paraesthesia. The efficacy of paraesthesia-free high and low amplitude burst SCS for the treatment of neuropathic pain in patients who are already familiar with tonic SCS was evaluated. MATERIALS AND METHODS: Forty patients receiving conventional (30-120 Hz) tonic SCS for at least six months were included. All patients received high and low amplitude burst SCS, for a two-week period in a double blind randomized crossover design, with a two-week period of tonic stimulation in between. The average visual analogue scale (VAS) scores for pain during the last three days of each stimulation period were evaluated as well as quality of life (QoL) scores, and patient's preferences. RESULTS: Average VAS score for pain were lower during high (40, p = 0.013) and low amplitude burst stimulation (42, p = 0.053) compared with tonic stimulation (52). QoL scores did not differ significantly. At the individual level 58% of the patients experienced significant additional pain reduction (>30% decrease in VAS for pain) during high and/or low amplitude burst stimulation. Eleven patients preferred tonic stimulation, fifteen high, and fourteen low amplitude burst stimulation. CONCLUSION: Burst stimulation is in general more effective than tonic stimulation. Individual patients can highly benefit from burst stimulation; however, the therapeutic range of burst stimulation amplitudes requires individual assessment.

A 2-center comparative study on tonic versus burst spinal cord stimulation: amount of responders and amount of pain suppression.

INTRODUCTION: Spinal cord stimulation is a safe and effective procedure applied for medically intractable neuropathic pain and failed back surgery syndrome. Recently, a novel stimulation paradigm was developed, called burst stimulation consisting of intermittent packets of closely spaced high-frequency stimuli. The design consists of 40 Hz burst mode with 5 spikes at 500 Hz per burst, with a pulse width of 1 ms and 1 ms interspike interval delivered in constant current mode. METHODS AND MATERIALS: A retrospective analysis is performed looking at 102 patients from 2 neuromodulation centers, 1 in Belgium and 1 in the Netherlands. This consisted of 2 groups, 1 group who had become failures to tonic (conventional) stimulation and 1 group who still responded to tonic stimulation. All patients were switched from tonic to burst stimulation and the amount of responders as well as the amount of pain suppression was assessed. RESULTS: Overall burst stimulation was significantly better than tonic stimulation and baseline. On average the pain on numeric rating scale (NRS) improved from 7.8 at baseline to 4.9 with tonic to 3.2 with burst stimulation. For the Belgian and Dutch centers combined, 62.5% of nonresponders to tonic stimulation did respond to burst stimulation, on average, with 43% pain suppression. Most responders to tonic further improved with burst stimulation; on average, pain suppression improved from 50.6% to 73.6.3%. The results (from both centers) did not differ for the amount of obtained pain suppression, only for the amount of responders, which could be related to the different profile of the 2 participating centers. CONCLUSIONS: Burst seems to be significantly better than tonic stimulation. It can rescue an important amount of nonresponders to tonic stimulation and can further improve pain suppression in responders to tonic stimulation.