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There were no morphological differences between the test and control groups. Any degeneration or histological change was noted in both groups at an equal incidence/severity. None of the observed changes had any clinical or biological relevance and none were considered adverse effects. The implanted device and proprietary stimulation parameters did not produce morphologic changes in the test samples after 10 days of stimulation not also observed in the controls. The equal incidence of change indicates that microscopic findings present in both groups were due to the placement/presence of the lead. It is assumed that any neuropathology attributed to electrical delivery would happen in an acute setting; thereby 240 hours of continuous stimulation provides ample time to produce toxicity. This study confirms that the novel stimulation parameters, including high frequency stimulation, do not produce neurotoxicity. Disclosure: Tiede – Paid consultant and share holder, Alataris and Walker – Corp employees and share holder, Butt – compensated research.
F703 SIMULTANEOUS NEUROSTIMULATION OF CERVICAL AND LOWER THORACIC SPINE FOR THE TREATMENT OF NEUROPATHIC PAIN OF THE UPPER AND LOWER EXTREMITIES E. Rokas *, A. Rovlias, S. Theodoropoulos, N. Paidakakos, M. Siakavella, E. Konstantinidis. Neurosurgery Department, General Hospital ‘Asclepieion’ Voulas, Athens, Greece Background and Aims: The objective of this study is to present the effectiveness of cervical SCS in the management of failed neck syndrome (FNS) on a patient who was also treated for FBS by an epidural lower thoracic stimulator, with excellent results on both painful syndromes. Methods: A 64 years – old woman with a history of four successive lumbar spine operations due to lumbar stenosis and two times operated with posterior approach for right cervical radiculopathy was admitted with sustained cervical radicular pain. A cervical SCS was inserted with dramatic decrease of symptomatology. Six years later she complained again for lower extremities radicular pain. A low thoracic spine stimulator was implanted. The patient had a significant pain relief and returned to her daily activity. Results: Three years from the primary insertion, we had to replace the cervical neurostimulator, due to increased patient’s needs. Because of this, we chose a rechargable stimulator for the FBS. Our patient is almost with no symptoms for both pain syndromes, with no specific pharmacy demands, still being observed for checking the function of stimulation systems. Conclusions: Epidural SCS is widely used in the management of chronic neuropathic pain, mainly on FBS. It may also be effective for the treatment of sustained cervical radiculopathy, when a proper selection of patients and indications are applied. Future application of multiprogramming stimulators covering wider pain areas, and ability of simultaneous stimulation and agents’ infusion into epidural space are promising a special interest on neuromodulation. Disclosure: None declared
F704 PREDICTING CLINICALLY RELEVANT PAIN REDUCTION AT 6 MONTHS IN CHRONIC PAIN PATIENTS TREATED WITH TENS A. Koke ¨ 1,2 *, R. Smeets2,3 , B. Winkens4 , M. van Kleef1 , J. Patijn1 . 1 Pain Management and Research Center, University Medical Center Maastricht, Maastricht, 2 Adelante Centre of Expertise in Rehabilitation, Hoensbroek, 3 Department of Rehabilitation Medicine, Research School CAPHRI, University Maastricht, 4 Department of Methodology and Statistics, Research School CAPHRI, Maastricht University, Maastricht, The Netherlands Background and Aims: Evidence for effectiveness of Transcutaneous Electrical Nerve Stimulation (TENS) is still inconclusive. Heterogeneity of chronic pain patients might be an important factor
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for this lack of efficacy. However due to differences in aetiology of pain and/or psychosocial factors one cannot expect that all patients with chronic pain will respond equally well to TENS. Identifying subgroups of patients who benefit most from treatment (what works for whom) is needed. Methods: A prospective cohort study was performed to identify variables with potential predictive value for a clinical relevant pain reduction ≥33% VAS (yes/no). At baseline a set of risk factors including pain related variables and psychological factors was measured. Univariate and multiple logistic regression analysis at 6 months were performed to find out factors associated with pain reduction. Results: At 6 months follow up 75 patients still used TENS compared to 74 patients not using TENS anymore. Univariate logistic regression analysis indicated that no multi sited pain (>2 pain locations), no constant pain, better mental and physical functioning and an external locus of control were all positively related to pain reduction ≥33%. In the multiple regression analyses, only not having multi sited pain, no constant pain and an external locus of control were independently related to clinically relevant pain reduction. Conclusions: The factors found in our study can be easily assessed in daily practice and can be used in deciding whether a patient should be referred for TENS treatment or not. Disclosure: None declared
F705 SPINAL CORD STIMULATION AND PREGNANCY ON PURPOSE OF A CASE WITHOUT INCIDENT P. Antonio *. Anesthesiology, University Hospital, Virgen del Rocio, Seville, Spain Background and Aims: The use of spinal cord stimulation for neuropathic pain control during pregnancy is an issue in dispute, particularly the lack of reported cases in which one can appreciate the possible complications of its use during the course of it. Recently, however, its use has been discouraged by the potential risks to the fetus and mother during pregnancy. Case description: We describe a case of pregnancy in a patient of 28 years of age at which a stimulator was implanted to control cervical neuropathic pain in the right upper limb secondary to an ulnar nerve neuropathy. The patient became pregnant four months after implantation and was informed of the controversy regarding the continuation of the spinal cord stimulation during pregnancy. Unable to advise any effective alternative therapies and the absence of clear data in the literature of adverse effects with respect to pregnancy of spinal cord stimulation, the patient decided to continue with this therapy. We proceeded to a strict course of the patient’s uterine activity throughout pregnancy and to track the status of the fetus. There were no signs of abnormal uterine hyperactivity or fetal abnormalities in the structure, both in utero and at the time of birth was by caesarean section at 39 weeks of gestation. In conclusion we believe we provide an interesting case for those in the future have to assess the possibility of maintaining or spinal cord stimulation for the treatment of neuropathic pain in pregnant patients. Disclosure: None declared
F706 CASE STUDY: SCS TO ACHIEVE LOW BACK PAIN RELIEF IN A PATIENT WITH TRAUMATIC SPINAL CORD TRANSECTION S. Sastry *, C. Gray. Lake Mary Pain Relief, Lake Mary, FL, USA Background and Aims: Patients with traumatic spinal cord injuries often experience persistent, unrelenting, chronic pain. These patients are often considered non-candidates for a trial of Spinal Cord Stimulation due to the disruption of the neural pathways as well as anatomic challenges. In many cases, it is thought that the
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injury itself prevents the patient from obtaining paresthesia from the SCS. Little has been published on the use of SCS for the chronic pain associated with traumatic spinal cord injury. Methods: Case study completed by retrospective review of the chart and via phone interviews with the patient. Two Spinal Cord Stimulator leads were placed in a 62 year old paraplegic patient with a spinal cord transection at the level of T12-L1 secondary to traumatic injury. Conservative therapies failed to provide the patient with significant pain relief. Trial leads were placed at L2–3, and C6-T1. Patient achieved paresthesia (stimulation overlap) from his back to his feet bilaterally using the cervical lead. The lumbar lead did not result in any desired paresthesia, and was therefore not used. Following the successful trial, patient was implanted with a tripole paddle lead and a conventional, non-rechargeable generator. Results: During the trial period, patient reported 80% pain relief in the low back. One year post-op, the patient reported 70% pain relief. Three years post-op, the patient reported 65% overall reduction in pain. Conclusions: Patients with traumatic spinal cord injury, resulting in chronic pain, may benefit from a trial of spinal cord stimulation. Further studies are warranted. Disclosure: None declared
F707 ALPHA FREQUENCIES IN THE PERIAQUADUCTAL GRAY PREDICT PAIN RESPONSE TO DEEP BRAIN STIMULATION A.B. O’Keeffe1 *, J. Hyam2 , S. Wang3 , J.-S. Britten1 , T. Aziz4 , A.L. Green4 . 1 Oxford University, 2 Nuffield Department of Surgery, Oxford University, Oxford, 3 Institute of Sound and Vibration Research, University of Southampton, Southampton, 4 Nuffield Department of Surgery and Department of Clinical Neurology, Oxford University, Oxford, UK Deep brain stimulation is an established treatment for chronic neuropathic pain syndromes. However, there are currently no well researched indicators of the best location within the periaquaductal gray (PAG) where stimulation provides optimal pain relief. In this study we analysed the resting local field potentials (LFPs) of eight patients implanted with PAG neurostimulators for chronic pain and related this data to clinically assessed pain relief. Awake, resting LFPs were recorded from patients after implantation of PAG stimulating electrodes and analysed using power spectral density analysis. Power spectral densities (PSD) were then compared to pain relief using the McGill pain score questionnaire. Correlation analysis was performed to assess the relationship between the PSD of resting local field potentials and post implantation pain relief. Higher levels of alpha band activity (8–15 Hz) in the PAG were correlated (R = −0.74) with lower percentage reductions in McGill pain scores after stimulation via the PAG electrode. This relationship was found to be significant (p = 0.038). Thus local field potentials in the alpha band (8–15 Hz) are negatively predictive biomarkers for an analgesic response to DBS for pain. Using these findings, insertion of DBS neurostimulators may be better tailored to obtain a good pain reduction response through identification of areas in the PAG with low levels of alpha band activity. Disclosure: None declared
F708 SPINAL CORD STIMULATION INDUCES PAIN RELIEF IN PAINFUL DIABETIC POLYNEUROPATHY E.A. Joosten1 *, W.A. Pluijms1 , R. Slangen1 , C.G. Faber1 , N.C. Schaper2 , M. van Kleef1 . 1 Anesthesiology, 2 Internal Medicine, Maastricht University Medical Center, Maastricht, The Netherlands Background and Aims: Painful diabetic polyneuropathy (PDP) is a common complication of diabetes mellitus. Treatment results are disappointing, leaving many patients with inadequate pain relief.
Spinal cord stimulation (SCS) has been proposed as a treatment modality for PDP which is unresponsive to drug therapy. Our primary objectives were to investigate 1. the technical feasibility of SCS in PDP, and 2. the efficacy of SCS in PDP. Methods: Patients suffering from moderate-to-severe PDP (NRS ≥5) were recruited for the study. The feasibility of achieving adequate paraesthesia coverage in both legs using one octapolar SCS lead was investigated during the implantation procedure. If adequate paraesthesia coverage was achieved, a 2-week trial stimulation period was performed to evaluate the effect of SCS. A definitive pulse generator was implanted if SCS resulted in clinically relevant pain relief. The effect of SCS on pain was assessed using numeric rating scales and patients’ global impression of change. Results: After screening for eligibility, 15 patients were included in the study. Adequate paraesthesia coverage in both legs was achieved in 14 patients (93%). Clinically relevant pain relief was reported by 11 patients (73%) after trial stimulation and by 10 patients (67%) after one year SCS treatment. Conclusions: SCS is feasible in patients suffering from PDP, since adequate paraesthesia coverage was achieved with in most patients. Moreover, SCS leads to clinically relevant pain relief in a majority of patients suffering from PDP. These results justify a randomized clinical trial to confirm these results in a controlled study. Disclosure: None declared
F709 COMPARISON OF MEDTRONIC PISCES® QUAD LEAD DURABILITY FOR PERIPHERAL AND SPINAL CORD STIMULATION IMPLANTS J. Tinsley1 *, K. Stromberg1 , M. Wells1 , C. Van den Abeele2 . 1 Clinical Research, Medtronic, Inc., Minneapolis, MN, USA; 2 Clinical Research, Medtronic, Inc., Tolochenaz, Switzerland Background and Aims: The Implantable Systems Performance Registry (ISPR) is a prospective, long-term multi-center registry to monitor the performance of Medtronic’s commercially available products in the United States. Medtronic’s percutaneous leads used for peripheral nerve stimulation (PNS) are not approved by the US FDA for this use; however, data from all lead implants are collected. Lead performance events specific to Pisces® Quad leads used for spinal cord stimulation (SCS) and PNS were compared. Methods: Data were collected from June 2004 through April 2010 in participating centers in the US. Leads were retrospectively identified as PNS implants, and their survival from product performance events requiring surgery or therapy suspension was compared to SCS leads using life-table methods. Results: There are 579 Quad leads with known SCS (n = 391) or PNS (n = 188) implant locations. Two sites implanted 94.7% of PNS leads. Product performance events were reported in 7 (3.7%) PNS leads, of which, 2 were due to lead migration/dislodgement and 5 to an undesirable change in stimulation. For SCS, product performance events were reported in 28 (7.2%) leads, of which, 8 were due to lead migration/dislodgement, 15 to undesirable change in stimulation, and 5 to fracture. At 30 months post-implant, survival from performance events was 95.1% (95% CI: 91.4–98.8%) for PNS leads and 91.3% (95% CI: 88.0–94.6%) for SCS leads (p-value = 0.199). Conclusions: Medtronic Quad leads used for PNS trend toward fewer product performance events than for SCS; however, the difference is not statistically significant. Results are limited by the retrospective design and small sample size. Disclosure: This registry is sponsored by Medtronic, Inc. All authors are employees of Medtronic, Inc.