Joel C. Rosenfeld MD, MEd, FACS

• Associate Clinical Professor of Surgery, University of Pennsylvania School of
• Medicine, Philadelphia, Pennsylvania
• St. Luke? Hospital and Health Network,
• Bethlehem, Pennsylvania

Both devices employ penetrating electrodes to interface with axons within the nerve treatment under eye bags purchase bimat with a visa. Current methods of peripheral nerve surgery demonstrate a wide range of successful nerve transplantation and reanimation procedures symptoms pink eye order bimat in united states online, particularly in the setting of trauma treatment resistant schizophrenia buy bimat overnight delivery. Peripheral neuroprosthetics extend the application of nerve transfer to allow for a new interface with external devices for functional restoration medications kidney disease bimat 3 ml without a prescription. The peripheral nervous system offers several attractive features to suggest a favorable site with which to interface symptoms esophageal cancer order bimat in india. In general treatment juvenile arthritis order generic bimat online, a peripheral nerve is more easily exposed with less surgical risk, maintains a consistent architecture, and provides direct access to both sensory and motor function. However, directly interfacing peripheral nerves to an external device has unique challenges. Sieve electrodes rely on nerve regeneration through small holes circumscribed by thin metal ring contacts. This class of electrodes is familiar to neurosurgeons in the application of vagal nerve stimulation for treatment of epilepsy. Prior studies have suggested that cuff electrodes are poorly suited for the selective subfascicular stimulation that is required to achieve fine motor control and are better suited for stimulation of the whole nerve. Extraneural electrodes may be extrafascicular, with various means of making contact with the epineurium, or interfascicular by penetrating the epineurium and placing contacts between the fascicles of a nerve. Examples of extraneural peripheral nerve electrodes include the button, book, helical, cuff, flat-interface nerve electrodes, and slowly penetrating interfascicular nerve electrodes (for review, see Navarro and associates63). The disadvantages of these designs may also include compression injury, ischemia, and poor contact properties. In doing so, less useful motor activation, such as a shoulder shrug, may be used to restore functionally effective actions in elbow flexion, hand grasp, or directly control of a robotic prosthesis. Examples include input to the somatosensory system for simulating proprioceptive and tactile stimulus, control of micturition and defecation by stimulating sacral nerves, and device-mediated pacing of the phrenic nerve for control of the diaphragm in respiration. More information on somatosensory input prostheses and cochlear implant devices is available at ExpertConsult. As scientific insight into the manner in which neurons in the brain and peripheral nerves underpin human intention and perception evolves, there will be new ways to effectively interface with the human nervous system to enable novel clinical therapeutics solutions. This evolution of technical and clinical capability will necessarily involve convergence across numerous different disciplines, including basic neuroscience, engineering, computer science, and neurosurgery. As these technologies approach clinical application, it will be imperative that neurosurgeons understand the fundamental principles that guide their creation and operation in order to best define their clinical application. Taken together, it is an exciting era for biomedical and neural engineering-one in which neurosurgeons stand to make great contributions to the field of neuroprosthetics and significantly affect those patients who have succumbed to neurologic injuries ranging from degenerative disease of the central nervous system to trauma of peripheral limbs. Grading of force and its precise application over a surface requires the somatic sense of touch and pressure. In the setting of limb amputation, peripheral nerves proximal to the injury often remain viable for direct interface. To achieve peripheral interface, however, intact upstream communication with spinal motor neurons is required. The ability to induce perception by electrical stimulation of the somatosensory cortex has been demonstrated in experimental primate models. This is due in part to the complex cellular architecture of the primary sensory area of the postcentral gyrus and the more difficult to access sulcus. The arrangement of the sensory homunculus along the long axis from medial to lateral of the postcentral gyrus and the Brodmann areas along the orthogonal axis makes for a significant challenge in localizing a particular sensory modality for an individual body area. However, in the peripheral nervous system, this arrangement is distributed among more easily isolatable nerves. After initial work demonstrated reliable sensory perception from direct stimulation of peripheral nerves,68 other groups have worked to further develop a bidirectional neuroprosthesis. Raspopovic and colleagues demonstrated the success of an intrafascicular electrode interface with the median and ulnar nerves for restoring sensory feedback to an individual with an upper extremity traumatic amputation 10 years prior. After experimentally titrating electrical stimuli through the range of perception from light touch to pain, these measurements were then applied according to pressure recordings from the attached neuroprosthetic device. From initial clinical work by Djourno and colleagues in France and Doyle and House in America, the cochlear implant has gone on to achieve remarkable success in the field of otolaryngology. Development of cochlear implants can be traced back at least 200 years to the Italian scientist Alessandro Volta, who invented the battery. He used the battery as a research tool to demonstrate that electric stimulation could directly evoke auditory, visual, olfactory, and touch sensations in humans. The disagreeable sensation, which I believe might be dangerous because of the shock in the brain, prevented me from repeating this experiment. Food and Drug Administration was commercially available in the mid1980s as a single-electrode device. Its basic design has benefited from advances in microscale electronics, electrode design, and mathematical processing methodologies. The components of a cochlear implant generally include a microphone, microprocessor, transmitter, receiver, stimulator, and electrode array. The microprocessor is responsible for analyzing sound recorded from the environment and transforming its acoustic properties into a useful signal. The microphone and microprocessor typically reside extracranially along with a transmitter. The transformed signal is then transmitted to an implanted receiver paired with an electrode array. The array has several stimulating electrode contacts that are implanted in a tonotopic orientation within the cochlea. Stimulation at electrodes along the length of the array induce the perception of sound at corresponding low to high frequencies. Device development for cochlear stimulation varies in the number of electrode contacts in the array as well as the sound-processing techniques employed. Although speech perception is possible with as few as 4 contacts, modern devices may implant more than 20 electrode contacts. Functional mapping of human sensorimotor cortex with electrocorticographic spectral analysis. Decoding two-dimensional movement trajectories using electrocorticographic signals in humans. On the relations between the direction of two-dimensional arm movements and cell discharge in primate motor cortex. Real-time prediction of hand trajectory by ensembles of cortical neurons in primates. Real-time control of a robot arm using simultaneously recorded neurons in the motor cortex. Reliability of signals from a chronically implanted, silicon-based electrode array in nonhuman primate primary motor cortex. Flexible, foldable, actively multiplexed, high-density electrode array for mapping brain activity in vivo. Human neocortical electrical activity recorded on nonpenetrating microwire arrays: applicability for neuroprostheses. Long-term gliosis around chronically implanted platinum electrodes in the Rhesus macaque motor cortex. Ultrasmall implantable composite microelectrodes with bioactive surfaces for chronic neural interfaces. Proceedings of the Fourth International Workshop on Advances in Electrocorticography. Classification of contralateral and ipsilateral finger movements for electrocorticographic braincomputer interfaces. Decoding flexion of individual fingers using electrocorticographic signals in humans. Decoding motor signals from the pediatric cortex: implications for brain-computer interfaces in children. Spatiotemporal dynamics of electrocorticographic high gamma activity during overt and covert word repetition. Decoding vowels and consonants in spoken and imagined words using electrocorticographic signals in humans. Neural decoding of single vowels during covert articulation using electrocorticography. Direct classification of all American English phonemes using signals from functional speech motor cortex. Microscale recording from human motor cortex: implications for minimally invasive electrocorticographic brain-computer interfaces. Recording sensory and motor information from peripheral nerves with Utah Slanted Electrode Arrays. Selective stimulation of cat sciatic nerve using an array of varying-length microelectrodes. Technology insight: future neuroprosthetic therapies for disorders of the nervous system. Intrafascicular stimulation of monkey arm nerves evokes coordinated grasp and sensory responses. A critical review of interfaces with the peripheral nervous system for the control of neuroprostheses and hybrid bionic systems. Effects of short-term training on sensory and motor function in severed nerves of longterm human amputees. On the electricity excited by the mere contact of conducting substances of different kinds. Parsa, Zvi Ram, and Raymond Sawaya Since the publication of the previous edition of this book, significant advances have been made in neuro-oncology in terms of understanding the genetic origins and evolution of brain tumors, particularly gliomas. In addition, continuing advances in technologies have allowed more refined and nuanced resections of tumors with sparing of normal brain function. In combination with the increased use of functional imaging and intraoperative imaging technologies, the work of the neurosurgical oncologist is increasingly precise. This section contains several outstanding and up-to-date basic/translational science chapters related to the pathobiology and pathogenetics of brain tumors, to the emerging importance of immunotherapy, and to the contribution of the tumor microenvironment to the tumor ecosystem. The bulk of this section, however, is dedicated to clinical neuro-oncology and clinical neuro-oncologic surgery. The histology, genetics, diagnosis, management, surgery, and adjuvant therapies are presented in a systematic manner by experts in the field. Ultimately, the objective is to provide the reader with the knowledge accumulated since the early 2000s, so that future advances can be reported in the context of past battles in the fight against brain cancers. However, as these advancements occur and prior questions are laid to rest, new controversies arise. These controversies originate from either gaps in knowledge, and serve as areas to direct further investigation, or from deficiencies in treatments, and represent areas in need of further innovation. A few of the current controversies in neuro-oncology are summarized and highlighted as follows. Aggressive Resection versus Partial Resection and Adjuvant Radiation Therapy for Craniopharyngiomas Craniopharyngiomas remain a neurosurgical challenge: despite advancements in surgical technique and radiotherapy modalities, the long-term rates of morbidity and mortality remain frustratingly high. There was no statistically significant difference between the two groups in either outcome measure; however, subtotal resection without radiotherapy resulted in significantly worse 5-year progression-free survival rates and 10-year overall survival rates. Partial or complete hypopituitarism occurs in a significant number of patients with craniopharyngioma, regardless of the treatment modality. It has been associated with attempts to remove adherent tumor from the hypothalamus12 and with hypothalamic radiotherapy doses higher than 51 Gy,21 both of which should be avoided. Visual deficits may occur as a presenting symptom, as a complication of recurrence, or as a consequence of surgery or radiotherapy. In studies with approximately 10 years of follow-up, visual deficits reportedly occur in 30% to 62. Modern techniques have reduced the neurocognitive effects of radiotherapy; as a result, some authors have advocated limited surgery and radiotherapy in an effort to improve neurocognitive and quality-of life-outcomes. Radiation Therapy versus Surgery for Glomus Jugulare Tumors the optimal management of glomus jugulare tumors remains controversial. The rarity of the tumors and paucity of literature on their management has hindered the identification of an optimal treatment. The available literature consists of small retrospective case series or meta-analysis of these small series. In addition, these studies are made up of heterogeneous groups, including recurrent cases, malignant tumors, various follow-up lengths, and differing definitions of control. Preoperative cranial nerve deficits were present in 46% of patients and one or more new cranial deficits occurred in 59% of cases. Radiosurgery offers the potential of tumor control without the morbidity associated with surgical resection. Reported tumor control rates are between 76% and 100%, and symptom control, between 88% and 100%. Tumor control was achieved in 93% with actuarial tumor progression-free survival rates of 97%, 89%, and 86% at 1, 3, and 5 years, respectively. Guss and associates64 performed a meta-analysis of radiosurgery studies for glomus jugulare tumors with a mean follow-up period of more than 36 months; they found a tumor control rate of 95% and clinical control of 96%, although the study was performed prior to the large series reported by Sheehan and colleagues. Only three comparative studies of radiosurgery versus microsurgery for glomus jugulare tumors have been published.

Psychiatric disorders and behavioral problems in children and adolescents with Tourette syndrome treatment 6th february order on line bimat. Contributions of the basal ganglia and functionally related brain structures to motor learning aquapel glass treatment discount 3 ml bimat with amex. Altered parvalbuminpositive neuron distribution in basal ganglia of individuals with Tourette syndrome medications used for anxiety discount 3ml bimat free shipping. Behavioural treatment of tics: habit reversal and exposure with response prevention medicine 8 - love shadow buy bimat 3 ml otc. Botulinum toxin for simple motor tics: a randomized medicine bottle purchase cheap bimat, double-blind medicine used for anxiety order bimat with american express, controlled clinical trial. Chronic bilateral thalamic stimulation: a new therapeutic approach in intractable Tourette syndrome. Double-blind clinical trial of thalamic stimulation in patients with Tourette syndrome. A trial of scheduled deep brain stimulation for Tourette syndrome: moving away from continuous deep brain stimulation paradigms. Microelectrode-guided deep brain stimulation for Tourette syndrome: within-subject comparison of different stimulation sites. Ackermans L, Temel Y, Cath D, et al; for the Dutch Flemish Tourette Surgery Study Group. Long-term, post-deep brain stimulation management of a series of 36 patients affected with 99 692. Thalamic deep brain stimulation for treatment-refractory Tourette syndrome: two-year outcome. Efficient internal pallidal stimulation in Gilles de la Tourette syndrome: a case report. Therapy-refractory Tourette syndrome: beneficial outcome with globus pallidus internus deep brain stimulation. Deep brain stimulation of globus pallidus internus in a 16-year-old boy with severe Tourette syndrome and mental retardation. Lessons Learned from Open-label Deep Brain Stimulation for Tourette Syndrome: Eight Cases over 7 Years. Deep brain stimulation for Gilles de la Tourette syndrome: a case series targeting subregions of the globus pallidus internus. Deep brain stimulation of the antero-medial globus pallidus interna for Tourette syndrome. Deep brain stimulation of the nucleus accumbens and the internal capsule in therapeutically refractory Tourette-syndrome. Nucleus accumbens deep brain stimulation did not prevent suicide attempt in Tourette syndrome. Deep brain stimulation of the right nucleus accumbens in a patient with Tourette syndrome. Lack of benefit of accumbens/capsular deep brain stimulation in a patient with both tics and obsessive-compulsive disorder. Neurosurgical treatment for Gilles de la Tourette syndrome: the Italian perspective. Patient selection and assessment recommendations for deep brain stimulation in Tourette syndrome. The Yale Global Tic Severity Scale: initial testing of a clinician-rated scale of tic severity. Deep brain electrophysiological recordings provide clues to the pathophysiology of Tourette syndrome. Annotation: Tourette syndrome: a relentless drumbeat-driven by misguided brain oscillations. Their clinical work was based on the success of frontal ablative procedures in primates by American neuroscientists John Fulton and Carlyle Jacobsen. Moniz and Almeida treated their first seven patients with ethanol injection into the centrum semiovale through a lateral trepanation in the skull. In 1942, they communicated their initial findings in 200 frontal lobotomy patients, reporting that 63% showed symptomatic improvement. The surgical treatment of various psychiatric disorders can be dated back to the origin of neurological surgery; however, surgery fell out of favor because of a poor understanding of the pathophysiology of psychiatric disorders and the high surgical morbidity and mortality associated with frontal lobotomy. Furthermore, variable reporting of surgical outcomes and availability of effective medications made surgical therapy obsolete. Various targets for ablation or neurostimulation have been described; however, owing to its reversibility, adaptability, and the ability to blind the stimulation for research studies, neurostimulation is presently considered superior to ablation when treating psychiatric disorders. Both the medical community and public viewed the procedure as inhumane and called for an end to the practice of psychosurgery. Furthermore, the advent of more effective pharmacotherapies ended this era of psychosurgery. In 1949 William Scoville published his technique of selective cortical undercutting to modify and study frontal lobe functions in humans. In addition, the introduction of a stereotactic coordinate system by French neurosurgeon Jean Talairach and Cartesian stereotactic systems developed by Spiegel and Wycis and by Leksell in late 1940s enabled neurosurgeons to perform psychosurgery with greater precision, thereby minimizing the complications associated with cruder frontal leucotomies. Schematic representation of neural circuits involved in the basic pathophysiology of obsessive-compulsive disorder. The functional organization of neural circuits implicated in the pathophysiology of psychiatric disorders is similar to that identified in patients with movement disorders. Each of these circuits includes functionally and anatomically discrete regions of the striatum, globus pallidus and substantia nigra, thalamus, and cortex. In the motor loop, motor and somatosensory cortical areas send partially overlapping projections to a specific region of the striatum. The striatum then sends projections that further converge at the level of the globus pallidus. From the globus pallidus, fully converged fibers project to a specific location in the thalamus. To close the loop, the thalamus projects back to a cortical area that feeds into the circuit. The net result is that several corticostriatal inputs that are functionally related are funneled together to a single cortical region in a feedback loop. Fibers originating from the prefrontal and orbitofrontal cortices project to the ventral striatum through the ventral internal capsule. The overall output of this pathway is inhibitory in nature and seeks to dampen the input to the cortex. These loops are also referred to as the direct and inhibitory pathways, respectively. In a normal state, this excitatory pathway is dampened by the net inhibitory output of the aforementioned basal ganglia-thalamocortical loop. Schematic representation of motor (A), associative (B), and limbic (C) circuits of the corticalstriatal-pallidal-thalamic-cortical loops implicated in the pathophysiology of movement and psychiatric disorders. When there is dysfunction in the striosomes, there is hyperactivity in the caudate nucleus, which is thought to lead to inhibition of negative feedback on the frontal cortices. Stereotactic Ablation Procedures With the advent of stereotaxis, procedures such as anterior cingulotomy, capsulotomy, subcaudate tractotomy, and limbic leucotomy were developed to help patients with severe and refractory psychiatric disorders. Furthermore, most studies regarding stereotactic ablative procedures are open label and nonrandomized. Anterior capsulotomy can be performed using either Gamma Knife or radiofrequency ablation. However, there are reports of patients attempting or committing suicide in the perioperative period. Another study reported side effects such as cerebral edema and headache (20%), asymptomatic infarctions in the caudate nucleus (10%), and frontal lobe dysfunction (3%) after Gamma Knife capsulotomy. Ballantine and associates performed the lesion 0 to 4 cm posterior to the tip of frontal horns, 7 mm lateral to midline, and 1 mm above the roof of the ventricles using electrically insulated thermistor electrodes. They reported that 25% (n = 8) of patients were responders/functionally normal, 31% (n = 10) showed marked improvement, whereas 41% (n = 14) showed slight or no improvement. These lesions are made by placing bilateral frontal bur holes 2 cm long in the anteroposterior plane of planum sphenoidale and 15 mm from the midline. StereotacticLimbicLeucotomy Limbic leucotomy involves interrupting the white matter tracts at the lower medial quadrant of each frontal lobe (subcaudate tractotomy) and those in the cingulum (cingulotomy). This ablative procedure is performed using either thermocoagulative or cryogenic techniques. Initially, it was proposed that high-frequency stimulation induces neuronal inhibition by depolarizing neurons in the vicinity of an electrode, a mechanism similar to ablation. One of these patients reported 90% improvement in her compulsive behavior and rituals after 2 weeks of stimulation. The major drawback of this study was lack of assessment scores to quantify improvements in mood or obsessive and compulsive behaviors after stimulation. This open study included four centers (three from the United States and one from Europe) over 8 years and documented a 13. In this study, patients were randomized in an on-off sequence of four 3-week blocks, with a mean follow-up of 4 to 23 months. Adverse effects included asymptomatic hemorrhage, seizure, superficial infection, and psychiatric symptoms such as hypomania and worsening of depression. They reported significant alleviation of symptoms in three patients (75%) at a follow-up of 24 to 30 months. Adverse events included agitation/anxiety (4 patients), hypomania (2 patients), concentration difficulties with failing memory (1 patient), suicidal thoughts (1 patient), headache (1 patient), weight gain (2 patients), reduction in sleep duration (1 patient), and dysesthesia in the subclavicular region (1 patient). Reported adverse events included mild forgetfulness, word-finding problems, hypomania, numbness at the incision site, superficial wound infection, and feeling the extension leads. Patients who meet criteria should then be assessed by a committee composed of a neurologist, functional neurosurgeon, neuropsychologist, bioethicist, and lay personnel. In addition, patients need to be educated and counseled regarding the surgical procedure, possible complications, and benefits of the procedure, maintaining realistic expectations of therapeutic results. It is also important to ensure that patients are able to understand the implications of the surgical procedure, are competent to make decisions on their own behalf, and are able to opt out of the study at any point. The surgical procedure is carried out by an experienced team composed of functional neurosurgeons, neurologists, and psychiatrists. A total of 15 serious adverse events occurred in 11 patients, including one intracerebral hemorrhage and two infections leading to hardware explantation. Stage 2 involves connecting the free end of the lead wire to an extension cable, which is subsequently tunneled under the scalp and skin of neck into the subclavicular or abdominal area and connected to the pulse generator. The stage 2 procedure is usually performed 7 to 10 days after the stage 1 procedure as an outpatient procedure under general anesthesia. A safe surgical trajectory to the target that avoids the cortical sulci, intracranial vessels, and ventricular walls is planned on the navigation station. With the patient in the supine position, an incision and bur hole are made, centered on the planned trajectory. The underlying dura mater is coagulated and opened at the desired entry point for the cannula, leaving adequate room to avoid hitting the dural edges. A cannula (length, 177 mm) is inserted through the pial opening to 15 mm above the target. The inner stylet of the cannula is removed, and a platinum-iridium or platinum- and gold-plated tungsten microelectrode with an impedance range of 0. The microelectrode is then advanced through the brain matter using a Neuronav Drive (Alpha Omega, Nazareth, Israel) in submillimetric steps in an awake patient. The neuronal activities within the target are evaluated by cognitive tasks every 1 to 2 mm along the length of the nucleus. The neuronal activity is amplified, filtered, displayed, and recorded using a high-quality audio monitor, computer display, and digital oscilloscopes. Each neuronal structure has characteristic electrophysiologic properties that assist in delineating the entry and exit points through that structure. Nevertheless, ablative procedures using radiofrequency thermocoagulation or Gamma Knife radiosurgery are still in use. The reversible and adjustable nature of this therapy may allow treating physicians to optimize therapy over time, but this remains unproved. Advances in neuroimaging continue to improve our understanding of the neural circuits and pathophysiology underlying psychiatric disorders. Parallel organization of functionally segregated circuits linking basal ganglia and cortex. Treatment of patients with intractable obsessivecompulsive disorder with anterior capsular stimulation. Deep brain stimulation of the ventral caudate nucleus in the treatment of obsessive-compulsive disorder and major depression. Deep brain stimulation of the nucleus accumbens for treatment-refractory obsessive-compulsive disorder. Deep-brain stimulation of the nucleus accumbens in obsessive compulsive disorder: clinical, surgical and electrophysiological considerations in two consecutive patients. Deep brain stimulation of the ventral internal capsule/ventral striatum for obsessive-compulsive disorder: worldwide experience. Unilateral deep brain stimulation of the nucleus accumbens in patients with treatment-resistant obsessive-compulsive disorder: Outcomes after one year. Electrical stimulation in anterior limbs of internal capsules in patients with obsessive-compulsive disorder. Sustained improvement of obsessivecompulsive disorder by deep brain stimulation in a woman with residual schizophrenia. The nucleus accumbens: a target for deep brain stimulation in obsessive-compulsive- and anxietydisorders. The epidemiology of obsessive-compulsive disorder in the National Comorbidity Survey Replication.

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Seizures usually develop by the end of the first year and may respond to medical treatment initially symptoms 7 days after iui bimat 3ml amex, but often become resistant to drugs treatment uterine fibroids purchase cheap bimat online. The cerebral manifestations generally involve the occipital or parietal cortex medicine 1800s quality bimat 3ml, or both medicine klonopin order bimat 3ml overnight delivery, but the entire cortex or large parts of it may be involved; however medicine 0025-7974 cheap bimat 3 ml free shipping, the pathologic changes remain restricted to one hemisphere treatment for 6mm kidney stone purchase bimat online now. Epilepsy surgery should be considered for patients with refractory seizures, but one has to differentiate between the need for hemispheric deafferentation and a multilobar or more restricted resection. Children with widespread hemispheric involvement are classic candidates for hemispheric deafferentation. Particularly problematic is the timing of surgery in children older than 7 or 8 years if the language-dominant hemisphere is affected by progressive disease. Some language function may still develop after surgery, even in children aged 4 to 7 years. It is not infrequent in many institutions to elect to proceed to surgery at a time before the point that the relentless severe epileptic seizures have caused irreversible damage to the unaffected hemisphere. This outcome may be minimized by accepting earlier surgery and earlier motor loss from surgery and not waiting until the disease process has destroyed the hemisphere. Another argument in support of hemispheric disconnection is the deleterious effect of frequent seizures on cognition and behavior, as well as other neurological functions. This complex of frequent seizures and neurological decline is sometimes called epileptic encephalopathy, and abolishing it constitutes a legitimate aim. Instead of giving the epileptic encephalopathy a chance to further impair the developmental and cognitive potential of the infant, this approach is particularly applicable when the cause of the epilepsy has been recognized as being untreatable early in the clinical course (such as hemispheric cortical malformations) and when repeated trials of antiepileptic drugs appear useless. The clinical syndrome is characterized by intractable epilepsy and progressive hemiparesis inexorably resulting in hemiplegia, mental decline, and hemispheric atrophy. The seizure disorder may begin with generalized seizures, but focal seizures are most frequent, and epilepsia partialis continua develops in a large proportion of patients. A characteristic imaging finding is perisylvian atrophy and encephalomalacia, and histologic findings typically include a perivascular infiltrate of T lymphocytes, which is associated with destruction of neurons. Indications the decision to perform hemispherotomy is straightforward for unihemispheric lesions that are either inborn or occurred around the time of birth and manifested during infancy or early childhood as frequent and intractable seizures. Hemispherotomy is also indicated for small infants with so-called catastrophic epilepsy, manifesting early after birth, usually from severe hemispheric damage or an inborn malformation in which lengthy drug treatment is known to be unsuccessful. The disconnection is performed on a mostly nonfunctional or partly destroyed hemisphere, where language and motor function either have been or will be transferred to the other hemisphere, as is the rule if the damage occurred during the intrauterine period or perinatally. These patients typically already have spastic hemiparesis, and although the procedure always results in loss of fine motor control of the hand and occasionally deterioration of gait, the majority of patients are able to walk and even use their arm and hand to a certain degree. Frequently an improvement in cognition and in presurgical behavioral problems may be seen. A relative contraindication may be seen in patients with independently arising seizures from the so-called healthy hemisphere. Occasional isolated contralateral seizure episodes may be acceptable because they do not automatically result from an independent seizure focus. Bilateral epileptogenic activity may be seen on the electroencephalogram in as many as 75% of patients, but it may be secondary and originate from the diseased hemisphere. Because bilateral involvement may represent an independent seizure focus and not just activity conducted from the diseased hemisphere, it is associated with a somewhat reduced probability of a seizure-free outcome after surgery. Nonetheless, high rates of freedom from seizures can still be achieved,35-36 as demonstrated in a large series in which 77% of patients with suspected bilateral disease were found to either be seizure free or have only "minor events. However, it has been my experience that patients who have grown up with incomplete hemianopia adjust well to this deficit. Mental retardation is no longer considered a contraindication in my institution and others. In most patients, this plus the clinical history is sufficient to establish the indications for surgery. If possible, neuropsychological testing is also performed to be able to quantify any changes that occur after surgery. An intracarotid amobarbital test (Wada test) will sometimes be necessary to demonstrate which hemisphere is language dominant and to exclude the presence of dissociated sensory and motor speech areas. With late-onset disease or other progressive disease types in which there are doubts about the hemispheric transfer of language functions, this test will be particularly important. In patients with contralateral ictogenic activity, the Wada test may be helpful for differentiating between ictal activity conducted from the diseased hemisphere and ictal activity arising from an autonomous focus in the "healthy" hemisphere. If the contralateral ictal activity disappears when amobarbital is injected into the affected hemisphere, it is safe to assume that the contralateral activity is a conducted phenomenon and will not adversely affect the prognosis. Intradural recordings may occasionally be used to identify the few patients in whom multilobar resections would be sufficient rather than complete hemispheric deafferentation. Adverse effects are more severe when the disease develops later in life and the hemiparesis is mild. Predictions of postoperative motor function have been tried based on preoperative motor function and cause of disease39 and were reliable when unilateral motor cortex stimulation on the unaffected hemisphere yielded bilateral motor responses. This is usually combined with disconnection of the frontal and parieto-occipital lobes and callosotomy, which is performed from within the ventricular system. Achievement of these goals will lead to better psychosocial development and improved quality of life. Although the second and third goals are very ambitious and cannot be attained in all cases, in some situations this objective is realized when all seizures are eliminated. Patients or parents need to be informed about the unavoidable side effects of hemispheric deafferentation: complete hemianopia and loss of some motor function, such as fine pincer movement of the thumb and index finger Hemispheric Deafferentation Techniques TranssylvianKeyholeTechnique the transsylvian keyhole technique requires limited exposure of the brain and uses disconnection steps almost exclusively with no resections. A lateral transsylvian/transventricular approach is performed through a small opening. Relationship of the insular cortical surface to the lateral hemispheric surface demonstrated in a nonfixed brain specimen. Relationship of important anatomic landmarks to one another projected onto the surface of a brain reconstructed from magnetic resonance images. A pure disconnection is possible from the choroidal point anteromesially through the lateral mass of the bulging amygdaloid body to the arachnoid covering the mesial aspect of the uncus. The hippocampus may be left in place as long as the mesiotemporal disconnection is carried backward along the choroidal fissure to the trigone, but some hippocampus may be harvested for histologic examination. The fourth step can be started when the surgeon can see the open fontal horn in the depth, the ascending M1 at the limen insulae, and the lateral surface of the frontal lobe. Demonstration of mesial disconnection lines for the technique of transsylvian/transventricular hemispheric deafferentation. The usefulness of these landmarks was also confirmed in an anatomic study,45 and details of this procedure have been described previously. The use of neuronavigation is advisable to correctly place the craniotomy so that the upper border is at the level of the corpus callosum and the lower border is 0. A certain risk for incomplete disconnection exists, as a result of a too anteriorly placed disconnection line frontobasally. Hydrocephalus can develop postoperatively, as is the case with all transventricular disconnection procedures. The reported incidence is 6 of 95 pediatric patients, treated with five shunts and one ventriculocisternostomy, equivalent to a shunt rate of 5. Shunt rates of 8%, 16%, 19%, and 23% were seen with related procedures,18,51-53 but even higher rates are reported for the older techniques. It is a vertical approach through a parasagittal craniotomy and involves much less brain resection and more disconnection. Two views of grossly enlarged ventricles demonstrating paramedian transection of callosal fibers from within the ventricle. Intraoperative microphotograph showing the occipitomesial disconnection along the tentorial margin in the trigonal area. Extensive ventricular exposure in a patient with marked atrophy and a porencephalic cyst. Transcortical access to the lateral ventricle via limited cortical resection to enable access to the foramen of Monro and the posterior thalamic region 3. Paramedian callosotomy, including transection of the posterior column of the fornix 4. Lateral transection between the thalamus and the striatum starting in the lateral ventricle and reaching down to the temporal horn 5. After completion of the anterior callosotomy, resection of the posterior part of the gyrus rectus and extension of the transection line laterally so that the head of the caput caudatum meets the substriatal transection line lateral to the thalamus the first reported series18 consisted of 83 children and had a seizure-free outcome rate of 74%. The advantages of this procedure include a low level of blood loss that necessitated transfusion in just 8% of cases. A possible disadvantage is the long distance that must be traversed between the cortical surface to the temporal horn and the frontal lobe base. Yet, in a recent study of 28 patients, the presence of residual insular cortex was positively correlated with persistent seizures. AlternativeClassicTechniques Two techniques based on extensive resection besides functional hemispherectomy are described briefly for comparison purposes. Anatomic hemispherectomy involves a large hemicraniotomy, clipping of the anterior and middle cerebral arteries and parasagittal veins, and stepwise or en bloc removal of the hemisphere. Hemidecortication or hemicorticectomy procedures rely on the principle that all seizures originate from the cortex and thus only the ictogenic cortex needs to be removed. These techniques are associated with a number of possible untoward effects linked to the large exposure, including severe hypotension, blood loss, and prolonged operative times. CombinedResection-DeafferentationTechniques the peri-insular hemispherotomy techniques combine moderate to limited resection of brain tissue with disconnections. The features common to all these procedures are a transventricular approach to the callosal fibers and a more limited craniotomy and exposure. When compared with the older anatomic resections, the incidence of hydrocephalus and severe intraoperative complications is decreased. Operative times are shorter and blood loss is less than with the anatomic hemispherectomy techniques, but possibly higher than with the two deafferentation procedures described by Schramm and Delalande. Residual insular cortex may be a source of persistent postoperative seizures, but not all surgical techniques include systematic removal or disconnection of the insular cortex. Some surgeons make an intraoperative decision based on electrocorticography and remove the cortex if abnormal spiking is present. The usual blood and neurological parameters are recorded, output is monitored, and if necessary, blood components are replaced. Any postoperative seizures need to be compared carefully for similarities to or differences in preoperative seizure types. Anticonvulsive medications in the postoperative period remain the same as preoperatively. In cases of significant perioperative blood loss and transfusion, it is prudent to administer additional anticonvulsants intravenously before termination of the general anesthetic. Early physiotherapy is mandatory, and if necessary, transfer to a rehabilitation center is arranged. Patients should be observed closely for any impairment of swallowing before a routine diet is initiated. There is no question that seizure outcomes after hemispherotomies and functional hemispherectomy are similar. In the light of these findings it is hard to find arguments in favor of anatomic hemispherectomy. It is critically important, however, that surgeons be comfortable and knowledgeable about the technique that they choose to use. Long-term stable good seizure outcomes have been reported from some centers at follow-up periods as long as 15 years,18,32,50,71,74 but in another large patient cohort, seizure-free rates of 78% at 6 months dropped to 70% at 2 years and 58% at 5 years. There is incontrovertible evidence that the cause of the seizure disorder influences outcome. Interpretation of outcome data per center needs to be done carefully because cause influences outcome and the composition of the patient groups varies considerably from center to center. Cognition and Behavior Patients with a typical cause and indication for hemispheric deafferentation often have below-average intelligence (79% in one series34) or mental retardation. This may be combined in a smaller subgroup with behavioral problems such as aggression or temper tantrums. Quality-of-life improvements have been described, regarding employment status33 and ambulation,24 even in adult surgery. The high number of 12 contributing centers and the variable mixture of causes do not allow one to conclude that hemispherotomies are consistently associated with better outcomes. In the Complications Incomplete disconnections can be unintentional and unrecognized in the operating room and are usually listed as a postoperative complication. Typical examples of intraoperative complications are marked blood loss, electrolyte disturbances, and coagulation disorders resulting from excessive blood loss or blood replacement therapy. Transient rises in temperature for a few days and even up to 10 days are typical and must be differentiated from true bacterial meningitis. Expected losses in motor function, speech, or visual fields are accepted and expected side effects, not complications. Death in the postoperative period in historical series was observed in 4% to 6% of cases, was reduced to around 2% with functional hemispherectomy techniques, and in modern series is reported to be around 1%, rarely 2%; in a review of 153 cases and my own series, the rate was 0. A certain incidence of hydrocephalus appears to be unavoidable, as with all procedures that involve opening the ventricular system. Late reappearance of seizures has been observed with variable frequency, rarely in some groups18 and more frequently in other series. The key element in this change was to replace resective steps with disconnective steps, which culminated in nearly exclusive disconnective surgery. These techniques are successful and less demanding on the patient because of decreased operative time and less blood loss. Outcomes are influenced more by the cause of the seizure disorder and less by the specific technique used. Hemispherotomies and hemispheric deafferentations continue to be some of the most successful types of epilepsy surgery. Cerebral hemispherectomy in pediatric patients with epilepsy: comparison of three techniques by pathological substrate in 115 patients.

If there is a disparity in the location of the fiducials facial treatment bimat 3 ml for sale, the system recognizes a movement and the prescribed sonication is not delivered treatment room discount 3ml bimat mastercard. Lastly symptoms for diabetes bimat 3 ml without prescription, a final adjustment of the transducer is made so that the natural focus is positioned to precisely match the stereotactic target treatment kidney failure buy bimat cheap online. This thermal neuromodulation provides the means to personalize and optimize the treatment on the basis of clinical feedback medications ok to take while breastfeeding buy generic bimat pills. Early imaging typically shows a small area (2 to 3 mm) of T2 hyperintensity at the site of ablation and can be used to plan additional ablation medicine and health proven 3ml bimat, which is performed until satisfactory tremor suppression is observed. Between sonications, the physician is able to interact with the patient to monitor his or her condition and to perform clinical assessments for somatosensory symptoms and motor performance as well as for tremor response (see Video 95-1). Resting and postural tremors are easily observed, and intention tremor can be assessed with finger-to-nose testing and/or by having the patient perform simple spiral and line drawings. Theoretically, pain-sensitive structures such as the dura and periosteum could be heated as high levels of acoustic energy are transmitted through the skull. If head pain occurs in the absence of cavitation, the acoustic power can be decreased and the sonication duration increased-a strategy that delivers more acoustic energy with a lower intensity that is often well tolerated by the patient. The treatment phase involves the following three stages of sonication: (1) focus alignment, (2) target verification, and (3) therapeutic ablation. With short exposure times, this temperature range theoretically does not reach the threshold at which tissue damage would occur. If necessary, the system can electronically adjust the thermal spot to precisely match the planned target location. During the verification stage, the acoustic energy dose is slowly escalated through an increase in power, duration, or both to elevate target temperatures moderately. We have observed that neurological effects begin to manifest at temperatures in the "low 50s," most notably transient or partial tremor suppression or paresthesia during Vim thalamotomy. For thalamic ablations, the shape of the focus must be monitored to avoid inferior-lateral heating toward the posterior limb of the internal capsule. An image-based movement detection algorithm is performed with each sonication to assess the position of the transducer within the coordinate system of the magnet. Chang nd coworkers29 found a similar trend in lesion volume using T1-weighted sequences, reporting mean lesion volumes of 98 mm3, 202 mm3, and 217 mm3 at 24 hours, 1 week, and 1 month, respectively. The most common reported side effects are thalamotomy-related, typically being mild or transient somatosensory or cerebellar deficits. Radiographic and clinical results of ventral intermediate nucleus (Vim) thalamotomy for tremor. Axial (A) and coronal (B) T1-weighted magnetic resonance images on postoperative day 1 demonstrating a 5-mm lesion in the Vim of the thalamus with surrounding edema. Preoperative (C) and postoperative (D) spiral and line drawing samples demonstrating a dramatic reduction in tremor after thalamotomy. Lipsman and coworkers31 similarly noted 1 patient with persistent paresthesia at 3-month follow up. Interestingly, Chang and colleagues29 have not reported any patients with postoperative paresthesia because they initially target the ventralis oralis posterior (Vop) nucleus. Several patients have reported vestibular phenomena during high-intensity sonications. Transient dizziness, falling sensation, and vertigo have been reported and may be related to vestibular activation during sonications. One of the strongest criticisms of ablative surgery in general is its destructive nature. Furthermore, thalamic ablations are usually performed only unilaterally because bilateral thalamic ablations carry a significant risk for speech difficulties after surgery. Importantly, histology was available to confirm the ablated tissue and the relatively sharp penumbra of the treatment. Since these seminal preliminary studies, relatively few patients have been enrolled in clinical trials to treat glioma or metastasis because of restrictive inclusion criteria and alternative treatment options. Neuropathic Pain the first demonstration of human brain tissue ablation with acoustic energy delivered through the intact skull occurred during centrolateral thalamotomy for neuropathic pain syndromes. Martin and colleagues33 treated nine patients suffering from a wide array of therapy-resistant pain syndromes: phantom limb, post-amputation pain, schwannoma, radiculopathy, brachial plexus injury, thalamic infarct, and idiopathic trigeminal neuralgia. Bilateral centrolateral thalamotomies without adverse clinical effects were created with a mean pain relief of 68% (range 30% to 100%). Jeanmonod and coworkers32 later reported longerterm outcomes with average improvements in pain of 49% at 3 months and 57% at 1 year. Magnetic resonance imaging-guided, high-intensity focused ultrasound for brain tumor therapy. Production of focal destructive lesions in the central nervous system with ultrasound. A study of 25 cases in which ultrasonic irradiation was used as a lobotomy procedure. Focused ultrasound-mediated noninvasive brain stimulation: examination of sonication parameters. Transcranial magnetic resonance imaging-guided focused ultrasound surgery of brain tumors: initial findings in 3 patients. Investigation of a large-area phased array for focused ultrasound surgery through the skull. A magnetic resonance imaging-compatible, large-scale array for trans-skull ultrasound surgery and therapy. Magnetic resonance imaging-guided focused ultrasound for thermal ablation in the brain: a feasibility study in a swine model. A magnetic resonance imaging, histological, and dose modeling comparison of focused ultrasound, radiofrequency, and Gamma Knife radiosurgery lesions in swine thalamus. The use of quantitative temperature images to predict the optimal power for focused ultrasound surgery: in vivo verification in rabbit muscle and brain. A comparison of surgical approaches for the management of tremor: radiofrequency thalamotomy, gamma knife thalamotomy and thalamic stimulation. Symptomatic and functional outcome of stereotactic ventralis lateralis thalamotomy for intention tremor. Gamma knife radiosurgery for thalamotomy in parkinsonian tremor: a five-year experience. A comparison of continuous thalamic stimulation and thalamotomy for suppression of severe tremor. Long-term follow-up of thalamic stimulation versus thalamotomy for tremor suppression. Different magnetic resonance imaging patterns after transcranial magnetic resonanceguided focused ultrasound of the ventral intermediate nucleus of the thalamus and anterior limb of the internal capsule in patients with essential tremor or obsessive-compulsive disorder. Magnetic resonance imagingguided, high-intensity focused ultrasound for brain tumor therapy. Magnetic resonance-guided focused ultrasound surgery: Part 2: A review of current and future applications. Image-guided high-intensity focused ultrasound for conduction block of peripheral nerves. The effect of high frequency sound waves on heart muscle and other irritable tissues. Influence of the pressure field distribution in transcranial ultrasonic neurostimulation. Transcranial focused ultrasound modulates the activity of primary somatosensory cortex in humans. It consists of sectioning of the peripheral branch of the spinal accessory nerve to the sternocleidomastoid muscle combined with posterior ramisectomy from C1 to C6. There are several modifications of the technique, and it often has been combined with targeted myotomies. In experienced hands it is a safe procedure with minimal and infrequent side effects. Dystonic tremor, which is more irregular than essential tremor, is most evident when the patient attempts to move the head in the direction contralateral to the force of the dystonia. In many instances patients employ a "sensory trick" such as touching the chin, holding the neck, or other maneuver, to decrease the dystonic activity. The mean age at onset is 41 years, and as with other forms of focal dystonia, there is a slight female preponderance (about 1. Until recently, both manifestations would have been referred to as primary dystonia but with regard to the reclassification of dystonia, idiopathic and inherited would be appropriate, respectively. Lateral shift depicts translation of the axis of the head in the horizontal plane, and sagittal shift in the sagittal plane. It is important to understand which muscles are involved and causing the dystonic posture or movements in an individual patient. This issue is even more important when a decision has to be made about which muscles should be denervated, because in a given patient, dystonic activity may vary in different muscles yet produce the same dystonic posture. The efficacy and safety of botulinum toxin have been demonstrated in several randomized controlled and open trials. The effect of botulinum toxin is usually noted about 1 week after injection, and the average duration of the benefit is 3 to 4 months. It has to be noted, however, that the average duration of maximum improvement is much shorter, side effects are more frequent, and immunogenicity is higher with botulinum toxin B. Anatomy of anterior cervical rhizotomy (intradural approach) and posterior ramisectomy (extradural approach). Intradural procedures initially targeted sectioning of the posterior cervical nerve roots, but attention soon shifted to the anterior roots. McKenzie developed intradural rhizotomy of the anterior upper cervical roots in combination with sectioning of the intradural spinal accessory nerve in the 1920s. Soon thereafter, Dandy, as well as Hamby and Schiffer,20 refined this procedure further. In different series, however, reported results and also complications were highly variable. Most studies claimed useful postoperative improvement in 60% to 90% of patients, but it was unclear to what extent symptomatic amelioration of abnormal postures or movements translated into improvement in functional disability, in particular regarding the high number of side effects. Rhizotomy could approach only the nerve roots from C1 to C3 bilaterally or from C1 to C4 on one side, but ramisectomy can be performed down from C1 to C6, either on one side or bilaterally, in the same session. When selective ramisectomy and peripheral denervation became increasingly popular, sometimes in combination with myotomy, rhizotomy was abandoned almost completely. Although newer botulinum toxin preparations tend to be less immunogenic, antibody-induced failure of therapy with botulinum toxin B has been described even at a rate of 44%. In some patients selective peripheral denervation may also serve as an adjunct or as an alternative to botulinum toxin injection. The patient and the treating neurologist need to be informed that a staged procedure may be necessary to achieve an optimal result. For example, in a patient with torticollis with rotation of the head to the right side, the combined procedure would include ipsilateral posterior ramisectomy and contralateral selective peripheral sternocleidomastoid muscle denervation, possibly combined with myotomy or myectomy of the sternocleidomastoid muscle. In a patient with retrocollis, bilateral posterior ramisectomy, eventually combined with muscle sectioning of posterior neck muscles, would be most useful. Posterior Ramisectomy Denervation of the posterior rami to the neck muscles is performed via a midline incision in the plane of the ligamentum nuchae, extending from the posterior rim of the foramen magnum to the spinous process of C6. Then the posterior neck muscles can be mobilized laterally by subperiosteal dissection. The inferior oblique capitis muscle is detached from its origin at the spinous process of C2. The posterior rami are identified in the cleavage plane that has been created, at the point where they emerge lateral to the facet joints. With the help of the surgical microscope and electrical stimulation, the small Occiput Greater posterior rectus muscle of the head Arch of atlas Vertebral artery Posterior branch C1 (suboccipital nerve) Inferior oblique muscle of the head Spinous process C2 Posterior branch C2 Articular facet C2 Semispinalis capitis muscle Posterior branch C3 Articular facet C3 Posterior branch C4 Posterior branch C5 Posterior branch C6 Semispinalis capitis m. Since its introduction by Bertrand, there have been several modifications of the original technique. However, because of the danger of air embolism, most neurosurgeons prefer to perform the ramisectomy with the patient in the prone position and sternocleidomastoid denervation after the patient is placed in the supine position. Great care is taken not to injure the greater auricular nerve, which crosses the operative field, to avoid postoperative hypesthesia of the earlobe. Then the trapezius branch of the spinal accessory nerve is identified in the lateral neck triangle. Following the trapezius branch, the main trunk of the spinal accessory nerve is reached. All branches to the sternocleidomastoid muscles are identified by electrical stimulation and then sectioned and resected. Small nerve fibers that may branch off from the trapezius branch of the spinal accessory nerve to supply the sternocleidomastoid muscle are carefully sought and sectioned as well. When the underside of the sternocleidomastoid muscle is elevated, further branches supplying the caudal portion of the muscle may be detected in addition. Because the sternocleidomastoid muscle may also be innervated by branches of spinal nerves C1 and C2, I usually complete the procedure with a myotomy and partial myectomy of the muscle within its fascia. The wound is closed with an intracutaneous suture to obtain a good cosmetic result. The posterior branches of C1-C6 can be reached within the natural cleavage plane between the more superficial semispinalis capitis muscle and the deeper multifidus and semispinalis cervicis muscles. The C1 branch is located between the vertebral artery and the arch of the atlas in the region of its vertebral sulcus about 1.