Comparison of tonic spinal cord stimulation, high-frequency and burst stimulation in patients with complex regional pain syndrome: a double-blind, randomised placebo controlled trial

BACKGROUND: Complex Regional Pain Syndrome (CRPS) is a disabling disease that is sometimes difficult to treat. Although spinal cord stimulation (SCS) can reduce pain in most patients with CRPS, some do not achieve the desired reduction in pain. Moreover, the pain reduction can diminish over time even after an initially successful period of SCS. Pain reduction can be regained by increasing the SCS frequency, but this has not been investigated in a prospective trial. This study compares pain reduction using five SCS frequencies (standard 40 Hz, 500 Hz, 1200 Hz, burst and placebo stimulation) in patients with CRPS to determine which of the modalities is most effective. DESIGN: All patients with a confirmed CRPS diagnosis that have unsuccessfully tried all other therapies and are eligible for SCS, can enroll in this trial (primary implantation group). CRPS patients that already receive SCS therapy, or those previously treated with SCS but with loss of therapeutic effect over time, can also participate (re-implantation group). Once all inclusion criteria are met and written informed consent obtained, patients will undergo a baseline assessment (T0). A 2-week trial with SCS is performed and, if successful, a rechargeable internal pulse generator (IPG) is implanted. For the following 3 months the patient will have standard 40 Hz stimulation therapy before a follow-up assessment (T1) is performed. Those who have completed the T1 assessment will enroll in a 10-week crossover period in which the five SCS frequencies are tested in five periods, each frequency lasting for 2 weeks. At the end of the crossover period, the patient will choose which frequency is to be used for stimulation for an additional 3 months, until the T2 assessment. DISCUSSION: Currently no trials are available that systematically investigate the importance of variation in frequency during SCS in patients with CRPS. Data from this trial will provide better insight as to whether SCS with a higher frequency, or with burst stimulation, results in more effective pain relief. TRIAL REGISTRATION: Current Controlled Trials ISRCTN3665525

Drug adverse events and system complications of intrathecal opioid delivery for pain: Origins, detection, manifestations, and management

Intrathecal drug delivery is effective for the treatment of cancer and nonmalignant pain in patients who do not respond well to oral opioids, in patients who cannot tolerate the side effects associated with opioids,. or in patients who show a large, permanent increase in dosage. Although intrathecal drug delivery is associated with pharmacological side effects and complications, its benefits far outweigh its risks. There are three main categories of potential adverse events associated with intrathecal drug delivery: pharmacologic side effects, surgical complications, and device-related complications. Prevention, early recognition, and prompt management of adverse events will optimize patient outcomes. Many adverse events either resolve on their own or can be managed with dosage or device adjustment. More serious complications may require surgical intervention or discontinuation of therapy. This paper will provide an overview of adverse events and complications. their origins, detection,manifestations, and management

Avoiding complications from spinal cord stimulation: practical recommendations from an international panel of experts.

Spinal cord stimulation (SCS) is an effective technique for the relief of neuropathic pain. Biologic complications are more prevalent within the first 3 months after implantation, are generally minor and reversible, and do not affect patients' acceptance of the treatment. Technically, hardware-related complications are uncommon and occur more frequently in the first 2 years following implantation of the device than after. Nevertheless, the incidence of technological complications can be relatively high if the technique is not performed correctly. Based on a review of the literature and on the experience and consensus of an expert panel, this manuscript attempts to provide practical guidelines, which may help implanters avoid some of the technological complications of SCS implantation. Areas covered by this article include patient positioning, the appropriate use of imaging, insertion of percutaneous and surgical leads, intraoperative stimulation, lead choice and suturing, considerations pre- and postimplantation, stimulation settings and regimens, implantable pulse generator positioning, and control of infections. It is hoped that these guidelines may help physicians to improve their SCS implantation technique and thereby improve the outcomes of the therapy. These guidelines should be of special value for newer centers starting SCS therapy for their patients

Stimulation of Dorsal Root Ganglia for the Management of Complex Regional Pain Syndrome: A Prospective Case Series

BackgroundComplex regional pain syndrome (CRPS) is a chronic and progressive pain condition usually involving the extremities and characterized by sensorimotor, vascular, and trophic changes. Spinal cord stimulation (SCS) is an effective intervention for this condition, but is hampered by the technical challenges associated with precisely directing stimulation to distal extremities. Dorsal root ganglia (DRG) may be more effective as a physiological target for electrical modulation due to recruitment of the primary sensory neurons that innervate the painful distal anatomical regions. MethodsEleven subjects diagnosed with uni- or bilateral lower-extremity CRPS were recruited as part of a larger study involving chronic pain of heterogeneous etiologies. Quadripolar epidural leads of a newly developed neurostimulation system were placed near lumbar DRGs using conventional percutaneous techniques. The neurostimulators were trialed; 8 were successful and permanently implanted and programed to achieve optimal pain-paresthesia overlap. ResultsAll 8 subjects experienced some degree of pain relief and subjective improvement in function, as measured by multiple metrics. One month after implantation of the neurostimulator, there was significant reduction in average self-reported pain to 62% relative to baseline values. Pain relief persisted through 12months in most subjects. In some subjects, edema and trophic skin changes associated with CRPS were also mitigated and function improved. Neuromodulation of the DRG was able to provide excellent pain-paresthesia concordance in locations that are typically hard to target with traditional SCS, and the stimulation reduced the area of pain distributions. ConclusionsNeuromodulation of the DRG appears to be a promising option for relieving chronic pain and other symptoms associated with CRPS. The capture of discrete painful areas such as the feet, combined with stable paresthesia intensities independent of body position, suggests this stimulation modality may allow more selective and consistent targeting of painful areas than traditional SCS

Lack of Body Positional Effects on Paresthesias When Stimulating the Dorsal Root Ganglion (DRG) in the Treatment of Chronic Pain

ObjectivesOne prominent side effect from neurostimulation techniques, and in particular spinal cord stimulation (SCS), is the change in intensity of stimulation when moving from an upright (vertical) to a recumbent or supine (horizontal) position and vice versa. It is well understood that the effects of gravity combined with highly conductive cerebrospinal fluid provide the mechanism by which changes in body position can alter the intensity of stimulation-induced paresthesias. While these effects are well established for leads that are placed within the more medial aspects of the spinal canal, little is known about these potential effects in leads placed in the lateral epidural space and in particular within the neural foramina near the dorsal root ganglion (DRG). Materials and MethodsWe prospectively validated a newly developed paresthesia intensity rating scale and compared perceived paresthesia intensities when subjects assumed upright vs. supine bodily positions during neuromodulation of the DRG. ResultsOn average, the correlation coefficient between stimulation intensity (pulse amplitude) and perceived paresthesia intensity was 0.83, demonstrating a strong linear relationship. No significant differences in paresthesia intensities were reported within subjects when moving from an upright (4.5 0.14) to supine position 4.5 (+/- 0.12) (p > 0.05). This effect persisted through 12 months following implant. ConclusionsNeuromodulation of the DRG produces paresthesias that remain consistent across body positions, suggesting that this paradigm may be less susceptible to positional effects than dorsal column stimulation

One-Year Outcomes of Spinal Cord Stimulation of the Dorsal Root Ganglion in the Treatment of Chronic Neuropathic Pain

ObjectivesSpinal cord stimulation of the dorsal root ganglion (DRG-SCS) is a new therapy for treating chronic neuropathic pain. Previous work has demonstrated the effectiveness of DRG-SCS for pain associated with failed back surgery syndrome, complex regional pain syndrome, chronic postsurgical pain, and other etiologies through 6 months of treatment; this report describes the maintenance of pain relief, improvement in mood, and quality of life through 12 months. Materials and MethodsSubjects with intractable pain in the back and/or lower limbs were implanted with an active neurostimulator device. Up to four percutaneous leads were placed epidurally near DRGs. Subjects were tracked prospectively for 12 months. ResultsOverall, pain was reduced by 56% at 12 months post-implantation, and 60% of subjects reported greater than 50% improvement in their pain. Pain localized to the back, legs, and feet was reduced by 42%, 62%, and 80%, respectively. Measures of quality of life and mood were also improved over the course of the study, and subjects reported high levels of satisfaction. Importantly, excellent pain-paresthesia overlap was reported, remaining stable through 12 months. DiscussionDespite methodological differences in the literature, DRG-SCS appears to be comparable to traditional SCS in terms of pain relief and associated benefits in mood and quality of life. Its benefits may include the ability to achieve precise pain-paresthesia concordance, including in regions that are typically difficult to target with SCS, and to consistently maintain that coverage over time