Effect of Dexmedetomidine on Perception of Paresthesia during Subthalamic Nucleus Deep Brain Stimulation Surgery for Parkinson's Disease

Background

Deep brain stimulation (DBS) has become a well-established treatment for the management of Parkinson's disease (PD). The most common method of lead targeting utilizes microelectrode recording (MER) and intraoperative macrostimulation to confirm accurate placement of the lead. This has been significantly aided by the use of dexmedetomidine (DEX) sedation during the procedure. Despite the frequent use of DEX, it has been theorized that DEX may have some effects on the MER during intraoperative testing. The effect on the perception of sensory thresholds during macrostimulation in the form of paresthesia is still unreported.

Objectives

To investigate the effect of the sedative DEX on sensory perception thresholds observed in the intraoperative versus postoperative settings for patients undergoing subthalamic nucleus (STN) DBS surgery for PD.

Materials and Methods

Adult patients (n = 8) with a diagnosis of PD underwent placement of DBS leads (n = 14) in the STN. Patients were subjected to intraoperative macrostimulation for capsular and sensory thresholds prior to placement of each DBS lead. These were compared to sensory thresholds observed in the postoperative setting during outpatient programming at three depths on each lead (n = 42).

Results

In most contacts (22/42) (P = 0.19), sensory thresholds for paresthesia perception were either perceived at a higher voltage or absent during intraoperative testing in comparison to those observed in the postoperative setting.

Conclusions

DEX appears to have measurable (though not statistically significant) effect on the perception of paresthesia observed during intraoperative testing.

A Case Report of Siblings with Dystonia: A Potential Link Between DYT11 Mutation and Platelet Dysfunction

Myoclonus-dystonia syndrome (MDS) is an autosomal dominant disorder due to a mutated epsilon-sarcoglycan gene (SGCE) at the dystonia 11 (DYT11) locus on chromosome 7q21-31. ε-sarcoglycan has been identified in vascular smooth muscle and has been suggested to stabilize the capillary system. This report describes two siblings with MDS treated with bilateral globus pallidus interna deep brain stimulation. One patient had a history of bleeding following dental procedures, menorrhagia, and DBS placement complicated by intraoperative bleeding during cannula insertion. The other sibling endorsed frequent epistaxis. Subsequent procedures were typically treated perioperatively with platelet or tranexamic acid transfusion. Hematologic workup showed chronic borderline thrombocytopenia but did not elucidate a cause-specific platelet dysfunction or underlying coagulopathy. The bleeding history and thrombocytopenia observed suggest a potential link between MDS and platelet dysfunction. Mutated ε-sarcoglycan may destabilize the capillary system, thus impairing vasoconstriction and leading to suboptimal platelet aggregation.

Neuromodulation in Obstructive Sleep Apnea

Epidemiological studies show a steady rise in the prevalence of obstructive sleep apnea (OSA). Untreated OSA is responsible for numerous chronic health conditions, motor vehicle, and workplace-related accidents leading to substantial economic burden both to the individual and society. Multiple causes for OSA and a wide range of consequences has made its diagnosis and treatment difficult. Obstructive sleep apnea may be caused by anatomical variation, increased collapsibility of the upper airway, low sleep arousal threshold, and exaggerated response to desaturation. Lifestyle changes, anatomical corrective surgeries, and oral appliances have been used but patient compliance is poor as it interferes in the daily routine. Neuromodulation is a promising functional modifying option that addresses the cause of obstructive sleep apnea at multiple levels.

Deep Brain Stimulation and Motor Cortex Stimulation for Chronic Pain

Deep brain stimulation (DBS) and Motor Cortex stimulation (MCS) have been used for control of chronic pain. Chronic pain of any origin is complex and difficult to treat. Stimulation of various areas in brain-like sensory thalamus, medial nuclei of thalamus including centro-lateral nucleus of thalamus (CL), periaqueductal gray, periventricular gray, nucleus accumbence and motor cortex provides partial relief in properly selected patients. This article reviews the pain pathways, theories of pain, targets for DBS and rationale of DBS and MCS. It also discusses the patient selection, technical details of each target.

Deep Brain Stimulation for Refractory Depression, Obsessive-Compulsive Disorder and Addiction

Background

Depression, Obsessive-compulsive Disorder (OCD), and addiction are the leading disabling psychiatric conditions with huge health care and psychosocial burden besides increased morbidity and mortality. Deep brain stimulation (DBS) for depression, OCD, and addiction is increasingly explored and is quite challenging. We present a brief review of the pertinent literature of DBS for depression, OCD, and addiction and present the status and challenges.

Objective

The aim of this study was to review the current status and challenges with the DBS for Depression, Obsessive-compulsive Disorder (OCD), and addiction.

Method

The pertinent brief literature was reviewed in reference to the DBS for Depression, Obsessive-compulsive Disorder (OCD), and addiction.

Results

To date, OCD is the only psychiatric condition approved for DBS therapy (under humanitarian device exemption). Although the initial encouraging results of DBS in depression were encouraging but the two larger multicenter clinical trials failed to meet the primary objective. Further evaluation and studies are ongoing. Similarly, the initial results of DBS for addiction are encouraging; however, the experience is limited.

Conclusion

DBS for depression, OCD, and addiction seem challenging but promising. Further refinement of the target and evaluation in a larger and controlled setting is needed, specifically for depression and addiction.

Microsurgery and Neuromodulation for Facial Spasms

Facial spasms are of various types. Hemifacial spasm (HFS) is characterized by unilateral tonic-clonic contractions of facial muscles, following a specific pattern of disease progression. It has well-delineated clinical, radiological and electrophysiological features. We have conducted an extensive review of existing literature on the subject, as regards etiopathogenesis, clinical features, investigations and management options for facial spasms. Primary Hemifacial spasm (HFS) may be treated using pharmacotherapy, botulinum toxin injections or microvascular decompression surgery. Microvascular decompression has the potential to reverse the pathological changes of the disease and has proved to be the most successful of all treatment options. Other facial spasms are exceedingly difficult to treat and may need neuromodulation as an option. The following article attempts to review the clinical features and therapeutic approaches to managing patients with facial spasms.

Fundamentals of Neuromodulation and Pathophysiology of Neural Networks in Health and Disease

Neuromodulation involves altering neuronal circuitry and subsequent physiological changes with the aim to ameliorate neurological symptoms. Over the years several techniques have been used to obtain neuromodulatory effects for treatment of conditions including Parkinson disease, essential tremor, dystonia or seizures. We provide brief description of the various therapeutics that have been used and mechanisms involved in pathophysiology of these disorders as well as the therapeutic mechanisms of the treatment modalities.

Neuromodulation Options and Patient Selection for Parkinson's Disease

Neuromodulation therapies, including deep brain stimulation (DBS) and pump therapies, are currently the standard of care for PD patients with advanced disease and motor complications that are difficult to control with medical management alone. The quest for alternate lesser invasive approaches led to the development of several novel therapies like intrajejunal levodopa infusions (IJLI), continuous subcutaneous apomorphine infusions (CSAI) and Magnetic Resonance guided Focused Ultrasound (MRgFUS) in recent years. To achieve good outcomes with any of these therapeutic modalities, careful patient selection, multidisciplinary evaluation and technical expertise are equally important. In this review, we will provide an overview of the neuromodulation strategies currently available for PD, emphasizing on patient selection and choosing among the various strategies.

Enhancing analgesic spinal cord stimulation for chronic pain with personalized immersive virtual reality

ABSTRACT

Spinal cord stimulation (SCS) is an approved treatment for truncal and limb neuropathic pain. However, pain relief is often suboptimal and SCS efficacy may reduce over time, requiring sometimes the addition of other pain therapies, stimulator revision, or even explantation. We designed and tested a new procedure by combining SCS with immersive virtual reality (VR) to enable analgesia in patients with chronic leg pain. We coupled SCS and VR by linking SCS-induced paresthesia with personalized visual bodily feedback that was provided by VR and matched to the spatiotemporal patterns of SCS-induced paresthesia. In this cross-sectional prospective interventional study, 15 patients with severe chronic pain and an SCS implant underwent congruent SCS-VR (personalized visual feedback of the perceived SCS-induced paresthesia displayed on the patient's virtual body) and 2 control conditions (incongruent SCS-VR and VR alone). We demonstrate the efficacy of neuromodulation-enhanced VR for the treatment of chronic pain by showing that congruent SCS-VR reduced pain ratings on average by 44%. Spinal cord stimulation-VR analgesia was stronger than that in both control conditions (enabling stronger analgesic effects than incongruent SCS-VR analgesia or VR alone) and kept increasing over successive stimulations, revealing the selectivity and consistency of the observed effects. We also show that analgesia persists after congruent SCS-VR had stopped, indicating carry over effects and underlining its therapeutic potential. Linking latest VR technology with recent insights from the neuroscience of body perception and SCS neuromodulation, our personalized new SCS-VR platform highlights the impact of immersive digiceutical therapies for chronic pain.Registration: clinicaltrials.gov, Identifier: NCT02970006.

Peripheral Neuromodulation for Chronic Pain

BACKGROUND

Chronic, focal, neuropathic pain is difficult to treat. Local nerve blocks are either ineffective or do not last. Regular neuromodulation modalities like spinal cord stimulation (SCS) or pain pump are invasive and affect a larger area.

OBJECTIVES

To discuss the indications, technique, nuances, programming, and outcomes of peripheral neuromodulation.

METHODS

The article reviews published literature and the author's own experience of over 500 cases of peripheral neuromodulation.

RESULTS AND CONCLUSION

Peripheral neuromodulation using peripheral nerve field stimulation (PNFS) is an effective, minimally invasive, targeted method of treatment. It is a relatively new modality in the field of neuromodulation but is used more often.

Direct Comparison of Posterior Subthalamic Area Stimulation versus Subthalamic Nucleus Deep Brain Stimulation in Parkinson's Disease

In this case report, we describe successful tremor capture via stimulation of the posterior subthalamic area (PSA) for a patient with tremor-predominant Parkinson's disease. In this scenario, the patient had a deep brain stimulation (DBS) lead placed in the PSA of the right hemisphere and a DBS lead placed in the subthalmic nucleus (STN) of the left hemisphere. Therefore, we were able to directly compare tremor capture in the same patient receiving stimulation in two different brain areas. We show that both placements are equally efficacious for tremor suppression, though the DBS lead placed in the PSA required slightly higher current intensity. This comparison in the same patient confirms that stimulation of the PSA can successfully suppress tremor in Parkinson's disease.

Predicting extended hospital stay after deep brain stimulation surgery in Parkinson's patients

BACKGROUND

The goal of deep brain stimulation (DBS) is to achieve maximal benefit for the patient while minimizing the likelihood of adverse effects. Currently, no standardized criteria exist that predicts extended hospital stay in DBS patients, although careful patient selection is recognized as a very important step for successful DBS therapy.

OBJECTIVES AND METHODS

The objective of this study was to identify eight key factors that predicted extended post-operative hospital stay following DBS lead implantation, in an effort to better identify patients that would require minimal hospital stay, resulting in reduced cost and reduced exposure to hospital- related problems. Univariate logistic regression models were used to examine associations between each factor and patients' post-surgical outcomes.

RESULTS

Using data collected from 183 patients, we found that 53 patients required a hospital stay longer than two days within one month post-procedure. Those who were 70 years or older and those who had frequent falls were significantly more likely to require extended post-surgical care. Patients that scored three points or higher on our eight-factor assessment scale had a greater likelihood of experiencing an event that would require an extended hospital stay following DBS lead placement, regardless of what three factors were present.

CONCLUSIONS

Any PD patient who is 70 years or older, incurring frequent falls, or with more than three points on our scale, should be carefully screened and cautioned about likely prolonged recovery and extended post-operative hospital stay.

Connectivity-based selection of optimal deep brain stimulation contacts: A feasibility study

Background

The selection of optimal deep brain stimulation (DBS) parameters is time‐consuming, experience‐dependent, and best suited when acute effects of stimulation can be observed (e.g., tremor reduction).

Objectives

To test the hypothesis that optimal stimulation location can be estimated based on the cortical connections of DBS contacts.

Methods

We analyzed a cohort of 38 patients with Parkinson's disease (24 training, and 14 test cohort). Using whole‐brain probabilistic tractography, we first mapped the cortical regions associated with stimulation‐induced efficacy (rigidity, bradykinesia, and tremor improvement) and side effects (paresthesia, motor contractions, and visual disturbances). We then trained a support vector machine classifier to categorize DBS contacts into efficacious, defined by a therapeutic window ≥2 V (threshold for side effect minus threshold for efficacy), based on their connections with cortical regions associated with efficacy versus side effects. The connectivity‐based classifications were then compared with actual stimulation contacts using receiver‐operating characteristics (ROC) curves.

Results

Unique cortical clusters were associated with stimulation‐induced efficacy and side effects. In the training dataset, 42 of the 47 stimulation contacts were accurately classified as efficacious, with a therapeutic window of ≥3 V in 31 (66%) and between 2 and 2.9 V in 11 (24%) electrodes. This connectivity‐based estimation was successfully replicated in the test cohort with similar accuracy (area under ROC = 0.83).

Conclusions

Cortical connections can predict the efficacy of DBS contacts and potentially facilitate DBS programming. The clinical utility of this paradigm in optimizing DBS outcomes should be prospectively tested, especially for directional electrodes.

Sandwich technique, peripheral nerve stimulation, peripheral field stimulation and hybrid stimulation for inguinal region and genital pain

OBJECTIVE

Ilioinguinal neuralgia (IG) and genitofemoral (GF) neuralgia following inguinal hernia repair is a chronic and debilitating neuropathic condition. Recently, peripheral nerve stimulation has become an effective and minimally invasive option for the treatment of refractory pain. Here we present a retrospective case series of six patients who underwent placement of peripheral nerve stimulation electrodes using various techniques for treatment of refractory post-intervention inguinal region pain.

METHODS

Six patients with post-intervention inguinal, femoral or GF neuropathic pain were evaluated for surgery. Either octopolar percutaneous electrodes or combination of paddle and percutaneous electrodes were implanted in the area of their pain. Pain visual analog scores (VAS), surgical complication rate, preoperative symptom duration, degree of pain relief, preoperative and postoperative work status, postoperative changes in medication usage, and overall degree of satisfaction with this therapy was assessed.

RESULTS

All six patients had an average improvement of 62% in the immediate post-operative follow-up. Four patients underwent stimulation for IG, one for femoral neuralgia, and another for GF neuralgia. Peripheral nerve stimulation provided at least 50% pain relief in all the six patients with post-intervention inguinal region pain. 85% of patients indicated they were completely satisfied with the therapy overall. There was one treatment failure with an acceptable complication rate.

CONCLUSION

Peripheral nerve or field stimulation for post-intervention inguinal region pain is a safe and effective treatment for this refractory and complex problem for patients who have exhausted other management options.

Emerging applications of deep brain stimulation

Deep brain stimulation (DBS) implantation surgery is an established treatment modality for a variety of medical refractory movement disorders such as Parkinson's disease, essential tremors and dystonia. Following the success of DBS in these movement disorders with a high rate of safety and efficacy, there is a resurgence of interest in the utility of this modality in other medical refractory disorders. Consequently, neuromodulation has been explored for a variety of refractory conditions such as neuropsychiatric disorders (major depressive disorders, obsessive-compulsive disorders, addictions), eating disorders including obesity, traumatic brain injury, post-traumatic stress disorders (PTSD), dementias and chronic pain. This review provides an overview of the emerging applications of DBS in these disorders, including summary of the published literature. We have highlighted the pathophysiology and likely aberrant neural circuits involved in these refractory disorders. Current and possible surgical targets for neurosurgical intervention related to these disorders have also been discussed. Furthermore, recent advances such as closed loop systems; responsive neurostimulation systems and optogenetics techniques have been addressed.

Restoring cortical control of functional movement in a human with quadriplegia

Millions of people worldwide suffer from diseases that lead to paralysis through disruption of signal pathways between the brain and the muscles. Neuroprosthetic devices are designed to restore lost function and could be used to form an electronic 'neural bypass' to circumvent disconnected pathways in the nervous system. It has previously been shown that intracortically recorded signals can be decoded to extract information related to motion, allowing non-human primates and paralysed humans to control computers and robotic arms through imagined movements. In non-human primates, these types of signal have also been used to drive activation of chemically paralysed arm muscles. Here we show that intracortically recorded signals can be linked in real-time to muscle activation to restore movement in a paralysed human. We used a chronically implanted intracortical microelectrode array to record multiunit activity from the motor cortex in a study participant with quadriplegia from cervical spinal cord injury. We applied machine-learning algorithms to decode the neuronal activity and control activation of the participant's forearm muscles through a custom-built high-resolution neuromuscular electrical stimulation system. The system provided isolated finger movements and the participant achieved continuous cortical control of six different wrist and hand motions. Furthermore, he was able to use the system to complete functional tasks relevant to daily living. Clinical assessment showed that, when using the system, his motor impairment improved from the fifth to the sixth cervical (C5-C6) to the seventh cervical to first thoracic (C7-T1) level unilaterally, conferring on him the critical abilities to grasp, manipulate, and release objects. This is the first demonstration to our knowledge of successful control of muscle activation using intracortically recorded signals in a paralysed human. These results have significant implications in advancing neuroprosthetic technology for people worldwide living with the effects of paralysis.

Spinal Cord Stimulation (SCS) and Functional Magnetic Resonance Imaging (fMRI): Modulation of Cortical Connectivity With Therapeutic SCS

INTRODUCTION

The neurophysiological basis of pain relief due to spinal cord stimulation (SCS) and the related cortical processing of sensory information are not completely understood. The aim of this study was to use resting state functional magnetic resonance imaging (rs-fMRI) to detect changes in cortical networks and cortical processing related to the stimulator-induced pain relief.

METHODS

Ten patients with complex regional pain syndrome (CRPS) or neuropathic leg pain underwent thoracic epidural spinal cord stimulator implantation. Stimulation parameters associated with "optimal" pain reduction were evaluated prior to imaging studies. Rs-fMRI was obtained on a 3 Tesla, Philips Achieva MRI. Rs-fMRI was performed with stimulator off (300TRs) and stimulator at optimum (Opt, 300 TRs) pain relief settings. Seed-based analysis of the resting state functional connectivity was conducted using seeds in regions established as participating in pain networks or in the default mode network (DMN) in addition to the network analysis. NCUT (normalized cut) parcellation was used to generate 98 cortical and subcortical regions of interest in order to expand our analysis of changes in functional connections to the entire brain. We corrected for multiple comparisons by limiting the false discovery rate to 5%.

RESULTS

Significant differences in resting state connectivity between SCS off and optimal state were seen between several regions related to pain perception, including the left frontal insula, right primary and secondary somatosensory cortices, as well as in regions involved in the DMN, such as the precuneus. In examining changes in connectivity across the entire brain, we found decreased connection strength between somatosensory and limbic areas and increased connection strength between somatosensory and DMN with optimal SCS resulting in pain relief. This suggests that pain relief from SCS may be reducing negative emotional processing associated with pain, allowing somatosensory areas to become more integrated into default mode activity.

CONCLUSION

SCS reduces the affective component of pain resulting in optimal pain relief. Study shows a decreased connectivity between somatosensory and limbic areas associated with optimal pain relief due to SCS.

Practical considerations and nuances in anesthesia for patients undergoing deep brain stimulation implantation surgery

The field of functional neurosurgery has expanded in last decade to include newer indications, new devices, and new methods. This advancement has challenged anesthesia providers to adapt to these new requirements. This review aims to discuss the nuances and practical issues that are faced while administering anesthesia for deep brain stimulation surgery.

Assessment of potential targets for deep brain stimulation in patients with Alzheimer's disease

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder affecting 36 million people worldwide and 5.2 million in the United States. The pathogenesis of AD is still elusive. Accumulations of abnormal proteins (beta amyloid and tau protein), inflammatory cascades, abnormal responses to oxidative stress and alteration in oxidative metabolism have been implicated in AD. There are few effective therapeutic options available for this disorder at present. Neuromodulation offers a novel treatment modality for patients with AD. The databases of Medline and PubMed were searched for various studies in English literature describing the deep brain stimulation (DBS) in patients with AD. Various animal and human clinical studies have shown promising initial results with bilateral DBS targeting various anatomical nodes. In this review, we attempt to highlight the pathophysiology, neural circuitry and potential neuromodulation options in patients with AD. In appropriately selected patients, DBS can potentially delay the cognitive decline, enhance memory functions and can improve the overall quality of life. However, further randomized controlled trials are required to validate the efficacy of neuromodulation and to determine the most optimal target for AD.

Accuracy and precision of targeting using frameless stereotactic system in deep brain stimulator implantation surgery

OBJECTIVES

To assess the accuracy of targeting using NexFrame frameless targeting system during deep brain stimulation (DBS) surgery.

MATERIALS AND METHODS

Fifty DBS leads were implanted in 33 patients using the NexFrame (Medtronic, Minneapolis, MN) targeting system. Postoperative thin cut CT scans were used for lead localization. X, Y, Z coordinates of the tip of the lead were calculated and compared with the intended target coordinates to assess the targeting error. Comparative frame-based data set was obtained from randomly selected 33 patients during the same period that underwent 65 lead placements using Leksell stereotactic frame. Euclidean vector was calculated for directional error. Multivariate analysis of variance was used to compare the accuracy between two systems.

RESULTS

The mean error of targeting using frameless system in medio-lateral plane was 1.4 mm (SD ± 1.3), in antero-posterior plane was 0.9 mm (SD ± 1.0) and in supero-inferior plane Z was 1.0 mm (SD ± 0.9). The mean error of targeting using frame-based system in medio-lateral plane was 1.0 mm (SD ± 0.7), in antero-posterior plane was 0.9 mm (SD ± 0.5) and in supero-inferior plane Z was 0.7 mm (SD ± 0.6). The error in targeting was significantly more (P = 0.03) in the medio-lateral plane using the frameless system as compared to the frame-based system. Mean targeting error in the Euclidean directional vector using frameless system was 2.2 (SD ± 1.6) and using frame-based system was 1.7 (SD ± 0.6) (P = 0.07). There was significantly more error in the first 25 leads placed using the frameless system than the second 25 leads (P = 0.0015).

CONCLUSION

The targeting accuracy of the frameless system was lower as compared to frame-based system in the medio-lateral direction. Standard deviations (SDs) were higher using frameless system as compared to the frame-based system indicating lower accuracy of this system. Error in targeting should be considered while using frameless stereotactic system for DBS implantation surgery.

Deep brain stimulation in Huntington's disease: assessment of potential targets

Huntington's disease (HD) is an autosomal-dominant neurodegenerative disorder that has very few effective therapeutic interventions. Since the disease has a defined neural circuitry abnormality, neuromodulation could be an option. Case reports, original research, and animal model studies were selected from the databases of Medline and PubMed. All related studies published up to July 2014 were included in this review. The following search terms were used: "Deep brain stimulation," "DBS," "thalamotomy," "pallidal stimulation," and "Huntington's Disease," "HD," "chorea," or "hyperkinetic movement disorders." This review examines potential nodes in the HD circuitry that could be modulated using deep brain stimulation (DBS) therapy. With rapid evolution of imaging and ability to reach difficult targets in the brain with refined DBS technology, some phenotypes of HD could potentially be treated with DBS in the near future. Further clinical studies are warranted to validate the efficacy of neuromodulation and to determine the most optimal target for HD.

Neuromodulation as a last resort option in the treatment of chronic daily headaches in patients with idiopathic intracranial hypertension

OBJECTIVE

To determine the feasibility and efficacy of occipital nerve stimulation (ONS) in patients with refractory headaches secondary to idiopathic intracranial hypertension (IIH).

BACKGROUND

IIH is a syndrome characterized by elevated intracranial pressures in the absence of a mass lesion. These patients typically present with chronic and intractable headaches. Cerebrospinal fluid (CSF) diversion fails in relieving the headache in a significant proportion of this population. ONS has been shown to be effective in medically refractory headaches and to our knowledge, has not been attempted as a therapeutic modality in this population.

METHODS

Four patients with occipital predominant chronic daily headaches and IIH who failed medical management underwent bilateral ONSs. Octopolar percutaneous electrodes were implanted in the defined area of pain. Visual Analog Scale (VAS) was used as an outcome measure. Patient demographics and surgical complications were also reviewed in this retrospective study. Following the trial period, all patients had >50% pain reduction resulting in permanent implantation.

RESULTS

All 4 patients had an average improvement of their VAS scores by 75%, with 85% spatial coverage and the remainder of the uncovered region being frontal. Sustained benefits were seen up to 3 years of follow-up. One patient had a lead erosion requiring removal followed by delayed re-implantation and another lost treatment efficacy at 2 years resulting in explantation. One patient required CSF diversion due to visual threat during the follow-up period but maintained sustained benefit from her ONS.

CONCLUSIONS

Bilateral ONS may be a useful treatment option in the management of selected patients with IIH, after standard surgical interventions have been attempted. Bilateral ONS may provide therapeutic option for management of residual headaches in these complicated patients.

Successful subthalamic nucleus deep brain stimulation therapy after significant lead displacement from a subdural hematoma

A 57-year-old man with a 21 year history of Parkinson's disease underwent bilateral subthalamic nucleus deep brain stimulation (DBS) placement. One week postoperatively he developed an acute left subdural hematoma from a fall with significant displacement of the DBS leads. It was promptly evacuated, the patient slowly recovered neurologically, and the leads again moved near to the original position. Six months of stimulation therapy attained 50% reduction in symptoms. This case report demonstrates the movement of DBS leads due to brain shift and their ability to come back to previous location once the brain shift is corrected.

Peripheral nerve stimulation by 'sandwich' paddle leads: technical note

BACKGROUND

Recently, there has been a burgeoning interest in the utility of peripheral nerve stimulation (PNS) for a variety of chronic focal neuropathic, musculoskeletal and visceral pain conditions. If the source of pain is directly related to a single peripheral nerve, surgical exposure and placing a paddle lead on the nerve are most effective.

METHODS

In this report, we describe a novel technique that optimizes the peripheral nerve stimulation by two paddle leads placed on either side of the nerve with their stimulating surfaces in contact with the nerve. After appropriate prepping and draping, the selected nerve is localized and circumferentially dissected free from the adjacent soft tissue. There should be enough length of nerve to accommodate two On-Point quadripolar leads (Medtronic, MN) along the length of the nerve in the same direction.

RESULTS

This 'sandwich' technique provides a wider interface of contacts with nerve fibers. It reduces the chance of migration and provides an opportunity for 'crosstalk.'

CONCLUSION

In selected cases where an open surgical PNS lead needs to be placed, the 'sandwich' technique can be used to augment the stimulation without additional morbidity. Although occasionally used in practice, this technique is still unreported.

Technological innovations in implants used for pain therapies

The field of pain management has experienced tremendous growth in implantable therapies secondary to the innovations of bioengineers, implanters, and industry. Every aspect of neuromodulation is amenable to innovation from implanting devices to anchors, electrodes, programming, and even patient programmers. Patients with previously refractory neuropathic pain syndromes have new and effective pain management strategies that are a direct result of innovations in implantable devices.

Transcranial magnetic stimulation for chronic pain

Current data suggest that transcranial magnetic stimulation (TMS) has the potential to be an effective and complimentary treatment modality for patients with chronic neuropathic pain syndromes. The success of TMS for pain relief depends on the parameters of the stimulation delivered, the location of neural target, and duration of treatment. TMS can be used to excite or inhibit underlying neural tissue that depends on long-term potentiation and long-term depression, respectively. Long-term randomized controlled studies are warranted to establish the efficacy of repetitive TMS in patients with various chronic pain syndromes.

Deep brain stimulation for movement disorders: patient selection and technical options

Deep brain stimulation (DBS) is used as a treatment for movement disorders. Unlike ablative procedures, DBS is reversible and adjustable. It is approved in the United States for treatment of Parkinson disease (PD), dystonia, and tremor. This surgical procedure is considered safe and effective for the management of the motor symptoms of these disorders, although it does not cure the underlying conditions. Potential complications of DBS surgery include intracranial hemorrhage, infections, and complications related to the hardware. There may also be complications related to stimulation or programming, although these are usually associated with dosages of dopaminergic medications and are reversible. DBS is usually performed under conscious sedation with awake evaluation during intraoperative physiologic testing. Typically, the procedure is performed with stereotactic image guidance, using computed tomography or magnetic resonance imaging (MRI) for targeting. Surgery can be accomplished with stereotactic frames or frameless systems. Recently, intraoperative MRI guidance has become available and is an alternative to the traditional surgical procedure, allowing for implantation of the DBS device under general anesthesia.

Deep brain stimulation: what can patients expect from it?

Deep brain stimulation has largely replaced ablative procedures for the treatment of advanced Parkinson disease, essential tremor, and dystonia. It is also approved for obsessive-compulsive disorder. Although not curative, it improves symptoms and quality of life.

Intracranial hemorrhage after removal of deep brain stimulation electrodes

Object

Many previous studies have shown that placement of deep brain stimulation (DBS) electrodes carries a considerable risk of hemorrhage. To date, no studies have evaluated the incidence of intracranial hemorrhage after removal of DBS electrodes. The authors performed a retrospective chart review to identify the incidence and trends in hemorrhage after DBS electrode removal.

Methods

A retrospective chart review of all DBS electrodes removed at the Cleveland Clinic between October 2000 and May 2010 was performed. All patients underwent postoperative CT scanning. Each patient was evaluated for age, sex, side of placement, target, duration of lead placement, reason for removal, and medical comorbidities.

Results

A total of 78 lead removals were performed in the 10-year period (1300 leads were implanted during the same period). Of the 78 leads removed, 10 (12.8%) resulted in hemorrhages seen on postoperative CT scans. The hemorrhages were superficial cortical in 6 cases of lead removal (60%) and deep in 4 cases (40%). No statistically significant correlation to any of the factors evaluated was found. All hemorrhages were asymptomatic. The authors' retrospective study of 78 DBS lead removals revealed a high risk of intracranial hemorrhage (12.8% per lead). The risk of hemorrhage during removal is significantly greater than the risk of hemorrhage during implantation (2.0% per lead at the authors' center during the same period). There were more superficial hemorrhages, and all hemorrhages were asymptomatic.

Conclusions

Removal of DBS leads carries a significantly higher risk of postoperative hemorrhages that are seen on images but are not clinically symptomatic.