Neurostimulation Approaches Research Articles

Selective Suprascapular and Axillary Nerve Block Provides Adequate Analgesia and Minimal Motor Block. Comparison with Interscalene Block

Background and objectiveShoulder arthroscopic surgeries evolve with intense postoperative pain. Several analgesic techniques have been advocated. The aim of this study was to compare suprascapular and axillary nerve blocks in shoulder arthroscopy using the interscalene approach to brachial plexus blockade. MethodsAccording to the technique used, sixty-eight patients were allocated into two groups: interscalene group (IG, n=34) and selective group (SG, n=34), with neurostimulation approach used for both techniques. After appropriate motor response, IG received 30mL of 0.33% levobupivacaine in 50% enantiomeric excess with adrenalin 1:200,000. After motor response of suprascapular and axillary nerves, SG received 15mL of the same substance on each nerve. General anesthesia was then administered. Variables assessed were time to perform the blocks, analgesia, opioid consumption, motor block, cardiovascular stability, patient satisfaction and acceptability. ResultsTime for interscalene blockade was significantly shorter than for selective blockade. Analgesia was significantly higher in the immediate postoperative period in IG and in the late postoperative period in SG. Morphine consumption was significantly higher in the first hour in SG. Motor block was significantly lower in SG. There was no difference between groups regarding cardiocirculatory stability and patient satisfaction and acceptability. Failure occurred in IG (1) and SG (2). ConclusionsBoth techniques are safe, effective, and with the same degree of satisfaction and acceptability. The selective blockade of both nerves showed satisfactory analgesia, with the advantage of providing motor block restricted to the shoulder.

Selective Suprascapular and Axillary Nerve Block Provides Adequate Analgesia and Minimal Motor Block. Comparison with Interscalene Block

Background and objectiveShoulder arthroscopic surgeries evolve with intense postoperative pain. Several analgesic techniques have been advocated. The aim of this study was to compare suprascapular and axillary nerve blocks in shoulder arthroscopy using the interscalene approach to brachial plexus blockade. MethodsAccording to the technique used, sixty-eight patients were allocated into two groups: interscalene group (IG, n=34) and selective group (SG, n=34), with neurostimulation approach used for both techniques. After appropriate motor response, IG received 30mL of 0.33% levobupivacaine in 50% enantiomeric excess with adrenalin 1:200,000. After motor response of suprascapular and axillary nerves, SG received 15mL of the same substance on each nerve. General anesthesia was then administered. Variables assessed were time to perform the blocks, analgesia, opioid consumption, motor block, cardiovascular stability, patient satisfaction and acceptability. ResultsTime for interscalene blockade was significantly shorter than for selective blockade. Analgesia was significantly higher in the immediate postoperative period in IG and in the late postoperative period in SG. Morphine consumption was significantly higher in the first hour in SG. Motor block was significantly lower in SG. There was no difference between groups regarding cardiocirculatory stability and patient satisfaction and acceptability. Failure occurred in IG (1) and SG (2). ConclusionsBoth techniques are safe, effective, and with the same degree of satisfaction and acceptability. The selective blockade of both nerves showed satisfactory analgesia, with the advantage of providing motor block restricted to the shoulder.

Transkranielle und invasive Hirnstimulationsverfahren bei Depression

Considering the substantial proportion of depressed patients which does not sufficiently benefit from antidepressant pharmacotherapy or psychotherapy, there is increasing interest in non-pharmacological antidepressant strategies. Thus, a whole array of stimulation approaches has been developed as potential new antidepressant interventions. These methods include transcranial convulsive and non-convulsive approaches, e.g. electroconvulsive therapy (ECT), magnetic seizure therapy (MST), transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) as well as invasive techniques, e.g. deep brain stimulation (DBS), vagus nerve stimulation (VNS) and epidural cortical stimulation (ECS). Each method represents a specific therapeutic approach with distinct targets within neural networks involved in the pathophysiology of depression. The ECT procedure is an established treatment with the highest efficacy of all antidepressant interventions and TMS reaches the highest level of evidence among the novel neurostimulation approaches and may be clinically used. However, the field yields a promising rapid development which may substantially enrich the armamentarium of antidepressant interventions in the near future.

Targeted hypoglossal neurostimulation for obstructive sleep apnoea: a 1-year pilot study

Continuous positive airway pressure (CPAP) is an effective but cumbersome treatment for obstructive sleep apnoea (OSA). Noncompliant patients need alternative therapies. We studied a tongue neurostimulation approach: targeted hypoglossal neurostimulation (THN) therapy with the aura6000™ System. A multi-contact electrode positioned around the main trunk of the twelfth nerve connected to an implanted pulse generator stimulates segments of the nerve, activating dilator muscles. The primary objective was to improve the polysomnographically determined apnoea/hypopnoea index (AHI) at 3 months, and maintain the improvement after 12 months of treatment. 13 out of 14 operated patients were successfully implanted. At 12 months, the AHI decreased from 45±18 to 21±17, a 53% reduction (p<0.001). The 4% oxygen desaturation index fell from 29±20 to 15±16 and the arousal index from 37±13 to 25±14, both p<0.001. The Epworth sleepiness scale decreased from 11±7 to 8±4 (p=0.09). THN was neither painful nor awakened patients, who all complied with therapy. There were two transient tongue paresis. The present study represents the longest study of any hypoglossal neurostimulation reported to date. We conclude that THN is safe and effective to treat OSA in patients not compliant with CPAP.

Wireless peripheral nerve stimulation increases pain threshold in two neuropathic rat models

Neurostimulation approaches including spinal cord and peripheral nerve stimulation are typically used to treat intractable chronic pain in individuals who are refractory to pain medications. Our earlier studies have shown that a voltage controlled capacitive discharge (VCCD) method of stimulation of nerve activation is able to selectively recruit activity in large myelinated nerve fibers. In this study, we were able to wirelessly activate the sciatic nerve using the VCCD waveform. The purpose of this study was to determine whether this waveform can effectively improve two of the most troublesome pain symptoms experienced by patients with chronic neuropathic pain mechanical and cold hyperalgesia. Neuropathic mechanical hyperalgesia was reproduced using the Spinal Nerve Ligation (SNL) rat model whereas cold allodynia was reproduced using the Chronic Constriction Injury (CCI) model in male rats. Von Frey and cold plate tests were used to evaluate paw withdrawal threshold and latency to withdrawal before and after stimulation in experimental and control rats. Paw withdrawal threshold increased significantly compared to post-lesion baseline after VCCD stimulation in SNL rats. We also observed a significant improvement in cold allodynia in the active implant CCI rats after stimulation. These results suggest that the VCCD stimulation using a wireless microstimulator may be effective in the treatment of neuropathic pain.

Neurostimulation: A New Way to Influence Cortical Excitability?

Recent work in humans suggests that strong static magnets can modulate cortical excitability for a limited period of time. Can this provide an alternative to current neurostimulation approaches?

B2 Complementary and alternative treatments for depression

Introduction: In 2001, the Canadian Psychiatric Association and the Canadian Network for Mood and Anxiety Treatments (CANMAT) partnered to produce evidence-based clinical guidelines for the treatment of depressive disorders. A revision of these guidelines was undertaken by CANMAT in 2008-2009 to reflect advances in the field. There is renewed interest in refined approaches to brain stimulation, particularly for treatment resistant major depressive disorder (MDD). Methods: PubMed, PsycInfo and the Cochrane database were searched for all publications relating to the use of neurostimulation approaches for depression, from January 2000 to December 2008. An evidence-based format was used with updated systematic reviews of the literature and recommendations were graded according to Level of Evidence using pre-defined criteria. Lines of Treatment were identified based on criteria that included evidence and expert clinical support. Results: Among the four forms of neurostimulation reviewed in this section, electroconvulsive therapy (ECT) has the most extensive evidence, spanning seven decades. Repetitive transcranial magnetic (rTMS) and vagus nerve stimulation (VNS) have been approved to treat depressed adults in both Canada and the United States with a much smaller evidence base. There is also emerging evidence that deep brain stimulation (DBS) is effective for otherwise treatment resistant depression, but this is an investigational approach in 2009. Compared to other modalities for the treatment of MDD, the data on the neurostimulation approaches to depression is limited by the relatively small numbers of randomized controlled trials (RCTs) and small sample sizes. Conclusions: There is most evidence to support ECT as a first-line treatment under specific circumstances and rTMS as a second-line treatment. Evidence to support VNS is less robust and DBS remains an investigational treatment.

Chronic Augmentation of the Parasympathetic Tone to the Atrioventricular Node: A Nonthoracotomy Neurostimulation Technique for Ventricular Rate Control During Atrial Fibrillation

The right inferior ganglionated plexus (RIGP) selectively innervates the atrioventricular node. Temporary electrical stimulation of this plexus reduces the ventricular rate during atrial fibrillation (AF). We sought to assess the feasibility of chronic parasympathetic stimulation for ventricular rate control during AF with a nonthoracotomy intracardiac neurostimulation approach. In 9 mongrel dogs, the small endocardial area inside the right atrium, which overlies the RIGP, was identified by 20 Hz stimulation over a guiding catheter with integrated electrodes. Once identified, an active-fixation lead was implanted. The lead was connected to a subcutaneous neurostimulator. An additional dual-chamber pacemaker was implanted for AF induction by rapid atrial pacing and ventricular rate monitoring. Continuous neurostimulation was delivered for 1-2 years to decrease the ventricular rate during AF to a range of 100-140 bpm. Implantation of a neurostimulation lead was achieved within 37 +/- 12 min. The latency of the negative dromotropic response after on/offset or modulation of neurostimulation was <1 s. Continuous neurostimulation was effective and well tolerated during a 1-2 year follow-up with a stimulation voltage <5 V. The neurostimulation effect displayed a chronaxie-rheobase behavior (chronaxie time of 0.07 +/- 0.02 ms for a 50% decrease of the ventricular rate during AF). Chronic parasympathetic stimulation can be achieved via a cardiac neurostimulator. The approach is safe, effective, and well tolerated in the long term. The atrioventricular nodal selectivity and the opportunity to adjust the negative dromotropic effect within seconds may represent an advantage over pharmacological rate control.

Neurostimulation approaches to primary headache disorders

Conventional management options in medically intractable chronic-headache syndromes, such as chronic migraine, chronic cluster headache and hemicrania continua, are often limited. This review summarizes the current concepts, approaches and outcome data of invasive device-based neurostimulation approaches using occipital-nerve stimulation and deep-brain stimulation. Recently, there has been considerable progress in neurostimulation approaches to medically intractable chronic-headache syndromes. Previous studies have analysed the safety and efficacy of suboccipital neurostimulation in drug-resistant chronic-headache syndromes such as in chronic migraine, chronic cluster headache and hemicrania continua. The studies suggest suboccipital neurostimulation can have an effect even decades after onset of headaches, thus representing a possible therapeutic option inpatients that do not respond to any medication. Similarly, to date over 50 patients with cluster headaches underwent hypothalamic deep-brain stimulation. From these, an average of 50-70% did show a significant positive response. These findings will help to further elucidate the clinical potential of neurostimulation in chronic headache.

IL-2: More Than a T Cell Growth Factor

CPAP is an effective but cumbersome treatment for obstructive sleep apnoea (OSA). Non-compliant patients need alternative therapies. We studied a tongue neurostimulation approach: Targeted Hypoglossal Neurostimulation (THN) therapy with the aura6000™ System. A multicontact electrode positioned around the main trunk of the XIIth nerve connected to an implanted pulse generator (IPG) stimulates segments of the nerve, activating dilator muscles. The primary objective was to improve the polysomnographically determined apnoea-hypopnoea index (AHI) at 3 months, and maintain the improvement after 12 months treatment. Thirteen out of 14 operated patients were successfully implanted. At 12 months the AHI decreased from 45±18 to 21±17, a 53% reduction, p&lt; 0.001. The 4% Oxygen Desaturation Index fell from 29±20 to 15±16 and the Arousal Index from 37±13 to 25±14, both p&lt;0.001. The Epworth Sleepiness Scale decreased from 11±7 to 8 ±4, p=0.09. THN was neither painful nor awakened patients, who all complied with therapy. There were two transient tongue paresis. The present study represents the longest study of any hypoglossal neurostimulation reported to date. We conclude that THN is safe and effective to treat OSA in patients not compliant with CPAP.

Supraclavicular continuous peripheral nerve block in a wounded soldier: when ultrasound is the only option

The complex nature of combat-related injuries requires frequent operative interventions and prolonged analgesic therapy. The application of continuous peripheral nerve block (CPNB) has been an important anaesthetic tool in the management of combat soldiers wounded from the current conflicts. The severe, destructive nature of combat injuries makes placement of CPNB difficult or impossible using more common neurostimulation approaches. The use of ultrasound technology has improved our success in placing CPNB in the presence of such injuries. We report the application of ultrasound technology in placing CPNB in a combat-injured soldier, whose injuries precluded other CPNB options.

An update on obsessive-compulsive disorder.

It is now recognized that obsessive-compulsive disorder (OCD) affects almost 3% of the world's population and is a major worldwide health problem. Much has been learned in the past 2 decades about the treatment of these disorders. Recent developments in neuroimaging techniques have led to a better understanding of the biology of OCD and the brain circuits that may be involved in the production of symptoms. The most effective treatment approaches, based on controlled data, are behavior therapy consisting of exposure and response prevention and specific medications. Although controversial, more invasive neurosurgical and neurostimulation approaches may hold some promise for severely disabled patients. Despite impressive research efforts, a small minority of patients remain refractory to treatment. Future clinical research should focus on this refractory group.