Dexmedetomidine Sedation in Magnetic Resonance-Guided Focused Ultrasound Thalamotomy: A Case Series of 3 Patients.

Magnetic resonance-guided focused ultrasound thalamotomy is an innovative minimally invasive treatment for medication-resistant tremor in patients with essential tremor and Parkinson disease. Sedation with common hypnotic agents is discouraged because the patient's cooperation is required during the procedure, and these drugs interact with the patient's tremor, interfering with the results of intraprocedural neurological evaluations. Dexmedetomidine may be the best choice for sedation during magnetic resonance-guided focused ultrasound thalamotomy, which can be prolonged and poorly tolerated by the awake patient. We report the first use of dexmedetomidine for sedation in magnetic resonance-guided focused ultrasound thalamotomy in 3 patients: none of them experienced relevant hemodynamic changes or apnea.

The Pioneering and Unknown Stereotactic Approach of Roeder and Orthner from Göttingen. Part II: Long-Term Outcome and Postmortem Analysis of Bilateral Pallidotomy in the Pre-Levodopa Era.

Before the advent of levodopa, pallidotomy was initially the most effective treatment for Parkinson disease, but it was soon superseded by thalamotomy. It is widely unknown that, similar to Leksell, 2 neurologists from Göttingen, Orthner and Roeder, perpetuated pallidotomy against the mainstream of their time. Postmortem studies demonstrated that true posterior and ventral pallidoansotomy sparing the overwhelming mass of the pallidum was accomplished. This was due to a unique and individually tailored stereotactic technique even allowing bilateral staged pallidotomies. In 1962, the long-term effects (3-year follow-up on average) of the first 18 out of 36 patients with staged bilateral pallidotomies were reported in great detail. Meticulous descriptions of each case indicate long-term improvements in parkinsonian rigidity and associated pain, as well as posture, gait, and akinesia (e.g., improved repetitive movements and arm swinging). Alleviation of tremor was found to require larger lesions than needed for suppression of rigidity. No improvement in speech, drooling, or seborrhea was observed. By 1962, the team had operated 13 patients with postencephalitic oculogyric crises with remarkable results (mean follow-up: 5 years). They also described alleviation of nonparkinsonian hyperkinetic disorders (e.g., hemiballism and chorea) with pallidotomy. The reported rates for surgical mortality and other complications had been remarkably low, even if compared to those reported after the revival of pallidotomy by Laitinen in the post-levodopa era. This applies also to bilateral pallidotomy performed with a positive risk-benefit ratio that has remained unparalleled to date. The intricate history of pallidotomy for movement disorders is incomplete without an appreciation of the achievements of the Göttingen group.

Sedation During Surgery for Movement Disorders and Perioperative Neurologic Complications: An Observational Study Comparing Local Anesthesia, Remifentanil, and Dexmedetomidine.

BACKGROUND: The anesthetic management of patients requiring surgery for movement disorders needs to balance microrecording quality and patient cooperation with safety and comfort. Anesthetics can alter microrecording, although the effect on outcome is debatable. They also provide a rested and cooperative patient and minimize complications such as intracranial hemorrhage by providing better hemodynamic control. Most teams use local anesthesia with monitored anesthesia care or conscious sedation with propofol. Recently, dexmedetomidine has emerged as an alternative that, at low doses, does not affect microrecording, and that does not impair respiratory drive. METHODS: In the past 15 years, we have used in our institution local anesthesia, remifentanil, or dexmedetomidine sedation. We compared functional outcome and rate of complications in a group of 145 patients with similar characteristics. RESULTS: We found 5 (3.4%) intracranial hemorrhages. Two (1.4%) were symptomatic. The remifentanil group had the highest risk of having systolic blood pressure >160 mm Hg during surgery (odds ratio [OR], 2.8; 95% confidence interval [CI], 0.9-9.9), whereas the dexmedetomidine group had the lowest (OR, 0.7; 95% CI, 0.2-1.8), compared with the local anesthesia group. Surgical time was shortest with dexmedetomidine (mean, 283 minutes) and longest with local anesthesia only (mean, 328 minutes). Functional outcome (Unified Parkinson's Disease Rating Scale, Part III motor component scale) was similar among groups. The dexmedetomidine group had a statistically significant lower risk of perioperative neurologic events compared with the local anesthesia group (OR, 0.09; 95% CI, 0.002-0.68). CONCLUSIONS: Sedation can be used safely without affecting outcome, and dexmedetomidine provides better hemodynamic management. Clinical significance remains unclear and larger studies need to be undertaken.

Speech and language adverse effects after thalamotomy and deep brain stimulation in patients with movement disorders: A meta-analysis.

BACKGROUND: The thalamus has been a surgical target for the treatment of various movement disorders. Commonly used therapeutic modalities include ablative and nonablative procedures. A major clinical side effect of thalamic surgery is the appearance of speech problems. OBJECTIVE: This review summarizes the data on the development of speech problems after thalamic surgery. METHODS: A systematic review and meta-analysis was performed using nine databases, including Medline, Web of Science, and Cochrane Library. We also checked for articles by searching citing and cited articles. We retrieved studies between 1960 and September 2014. RESULTS: Of a total of 2,320 patients, 19.8% (confidence interval: 14.8-25.9) had speech difficulty after thalamotomy. Speech difficulty occurred in 15% (confidence interval: 9.8-22.2) of those treated with a unilaterally and 40.6% (confidence interval: 29.5-52.8) of those treated bilaterally. Speech impairment was noticed 2- to 3-fold more commonly after left-sided procedures (40.7% vs. 15.2%). Of the 572 patients that underwent DBS, 19.4% (confidence interval: 13.1-27.8) experienced speech difficulty. Subgroup analysis revealed that this complication occurs in 10.2% (confidence interval: 7.4-13.9) of patients treated unilaterally and 34.6% (confidence interval: 21.6-50.4) treated bilaterally. After thalamotomy, the risk was higher in Parkinson's patients compared to patients with essential tremor: 19.8% versus 4.5% in the unilateral group and 42.5% versus 13.9% in the bilateral group. After DBS, this rate was higher in essential tremor patients. CONCLUSION: Both lesioning and stimulation thalamic surgery produce adverse effects on speech. Left-sided and bilateral procedures are approximately 3-fold more likely to cause speech difficulty. This effect was higher after thalamotomy compared to DBS. In the thalamotomy group, the risk was higher in Parkinson's patients, whereas in the DBS group it was higher in patients with essential tremor. Understanding the pathophysiology of speech disturbance after thalamic procedures is a priority. © 2017 International Parkinson and Movement Disorder Society.

Clinical Characteristics and Long-Term Outcomes of Movement Disorders in Childhood Thalamic Tumors.

BACKGROUND: We studied the outcomes of movement disorders that were associated with childhood thalamic tumors. METHODS: We retrospectively reviewed 83 children with thalamic tumors treated at our institution from 1996 to 2013 to document the incidence and outcome of movement disorders. Magnetic resonance imaging was used to analyze the involvement of thalamic nuclei, and three instruments were used to rate the severity of the disorders. RESULTS: Nine (11%) patients had one or more of the following movement disorders: postural tremor, resting tremor, ballism, dystonia, myoclonus, and athetosis. Median age at tumor diagnosis was seven years (range, 0.25 to 11 years), and the average age at movement disorder onset was eight years (range, 1.5 to 11 years). Movement disorders developed at a median of 1.5 months (range, 0 to 4 months) after surgical resection. The severity of the disorders was either unchanged or slightly improved during follow-up. The red nuclei were the only thalamic structures that showed tumor involvement in all nine patients. CONCLUSIONS: No specific injury of the thalamic nuclei was associated with movement disorders in children with thalamic tumors, and the severity of these disorders did not change over time.

[Role of neurosurgical management in movement disorders other than Parkinson disease].

Neurosurgical procedures are indispensable in management of various types of movement disorders (MD). Stereotactic operations that have been well established include deep brain stimulation for tremor, dystonia, and Parkinsonian symptoms. Recently the actual role of stereotactic ablative procedures such as thalamotomy and pallidotomy has been re-explored, and Vo thalamotomy shows long-term improvement of task specific focal dystonia like writer's cramp and musician's dystonia. A new less invasive treatment of tremor using MR guided focused ultrasound has started and is promising. Intrathecal administration of baclofen is also an established treatment for severe spasticity, but other ablative procedures such as peripheral neurotomy and dorsal rhizotomy are also important in spasticity treatment. It seems that most neurologists are unfamiliar, at least in Japan, with such neurosurgical procedures. However, neurologists involved in management of MD should understand the important roles of neurosurgical management of intractable MD and should refer such patients to appropriate neurosurgeons before permanent contracture and deformity develop.

Impact of parameters of radiofrequency coagulation on volume of stereotactic lesion in pallidotomy and thalamotomy.

BACKGROUND: One of the many reasons why lesional surgery for movement disorders has been more or less abandoned may have been the difficulty in predicting the shape and size of the stereotactic radiofrequency (RF) lesion. OBJECTIVES: To analyse the contribution of various RF coagulation parameters towards the volume of pallidotomies and thalamotomies. METHODS: The relationship between temperature of coagulation, length of coagulated area and duration of coagulation on the one hand, and lesion volume on the other was retrospectively evaluated. Lesion diameters were measured on stereotactic thin-slice CT and MRI scans, and volumes of lesions were calculated concerning 36 pallidotomies and 14 thalamotomies in 46 patients who were operated using the same RF generator and same RF electrode. RESULTS: The coagulation temperature, length of coagulated area and duration of coagulation were all correlated to the lesion volume. However, for a given length of coagulated area, the lesion´s size was most strongly influenced by the temperature. Despite this clear correlation, and the relatively homogenous coagulation parameters, the lesions' volumes were markedly scattered. CONCLUSIONS: The volume of the stereotactic RF lesions could be correlated with the coagulation parameters, especially the temperature, at a group level, but could not be predicted in individual patients based solely on the RF coagulation parameters.

Lesioning and stimulation in tremor-predominant movement disorder patients: an institutional case series and patient-reported outcome.

BACKGROUND: In certain movement disorder cases, a combined stimulation and lesioning approach in the same patient could be the ideal beneficial option. OBJECTIVES: The object of this study was to retrospectively examine the indications, outcome and complications in patients who had undergone both a lesioning (thalamotomy) and deep brain stimulation (DBS) procedure (bilateral or unilateral) for a tremor-predominant movement disorder performed by a single surgeon at one institution over a 15-year period. METHODS: A retrospective review of patient records was undertaken. Patient outcome was based on follow-up visit chart notes and on a non-validated patient telephone questionnaire. RESULTS: Thirty patients required a combined stimulation and lesioning approach to control tremor. Twelve patients had either unilateral or bilateral DBS as the first procedure followed by thalamotomy; two patients required a third procedure. Eighteen patients had thalamotomy as the first procedure followed by contralateral DBS either as the second or the third procedure. Eight patients required three procedures, which included either a repeat thalamotomy or a repeat DBS. We were able to contact 22 of 30 (15 male and 15 female, average age 70.7 ± 15.4 years) tremor-predominant movement disorder patients, retrospectively. Patient-reported outcome as assessed by a non-validated telephone questionnaire was: improvement in both symptoms and function in 59%, symptom but not function improvement in 32% and no improvement in either symptom or function or worsening in 9%. In comparison, based on retrospective chart review, 77% of patients had improved symptoms and functions, 20% of patients had improved symptoms with no effect on function and 3% of patients had no improvements of symptoms or functions. CONCLUSIONS: Lesioning, which has to a great extent fallen out of favor, still has a valuable role to play in the treatment of tremor-predominant movement disorders; it can still be applied in combination with stimulation with outcome results similar to that of bilateral stimulation.

[Stereotactic radiosurgery for movement disorders]. / Stereotaktyczna radiochirurgia w leczeniu chorób ruchu.

Nowadays, functional neurosurgery is an established treatment for movement disorders such as Parkinson's disease, essential tremor, and dystonia. The effectiveness and safety of neuromodulation procedures (deep brain stimulation) replaced in the last years ablative irreversible stereotactic lesions for movement disorders. Stereotactic radiosurgery with gamma knife is a non-invasive form of treatment for movement disorders. The main limitation of stereotactic radiosurgery is the impossibility of electrophysiological confirmation of the target structure. Nevertheless, patients with advanced age and significant medical conditions that preclude classic open stereotactic procedures or patients who must receive anticoagulation therapy may gain great functional benefit using gamma knife stereotactic radiosurgery.

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.

Functional neurosurgery. The modulation of neural and mind circuits.

Different complex neuroanatomical and neurochemical circuits regulate a variety of neuronal behaviors and brain functions. Any disturbance in these circuits can generate functional disorders such as movement disorders, epilepsy, pain, memory disorders, and psychiatric disorders. Functional neurosurgery aims to restore these functions, either by removing or isolating the abnormally behaving neurons or by modulating the disturbed circuits. Neuromodulation is a fast-growing field, powered by the recent advances in neuroimaging and technology. Here, we discuss recent advances and new horizons in functional neurosurgery.

Alleviation of drenching sweats following subthalamic deep brain stimulation in a patient with Parkinson's disease--a case report.

We report a patient with Parkinson's disease whose whole body drenching sweats were completely alleviated by stimulation of the subthalamic nucleus and/or adjacent structures. Sweating reappeared 4h after the pulse generator (stimulation) was turned off and ceased when stimulation was resumed. Imaging studies with reconstruction indicated that stimulation of, or spread of stimulation from, the caudal medial aspect of the right subthalamic nucleus and/or the caudal aspect of the ventral thalamus/zona incerta may be responsible for alleviating the drenching sweats.

Combined diffuse light reflectance and electrical impedance measurements as a navigation aid in deep brain surgery.

AIM: The aim of this study is to assess reflected light intensity combined with impedance as a navigation aid during stereotactic neurosurgery. METHODS: During creation of 21 trajectories for stereotactic implantation of deep brain stimulation electrodes in the globus pallidus internus or subthalamus (zona incerta or subthalamic nucleus), impedance at 512 kHz and reflected light intensity at 780 nm were measured continuously and simultaneously with a radio frequency electrode containing optical fibres. The signals were compared with the anatomy, determined from pre- and post-operative MRI and CT. The measurements were performed within minutes, and signal analysis was done post-operatively. RESULTS: Reflected light intensity was low from the cortex, lateral ventricle, caudate nucleus and putamen; intermediate from the globus pallidus and thalamus; while it was high from the subcortical white matter, internal capsule and subthalamus. The electrical impedance was less consistent, but generally low in the cortex, intermediate in the subcortical white matter, putamen, globus pallidus and thalamus, and high in the internal capsule and subthalamus. CONCLUSION: Reflected light intensity and electrical impedance give complementary information about passed tissue, and the combination seems promising as a navigation aid during stereotactic neurosurgery.

[Surgical treatment of movement disorders]. / Traitement chirurgical des pathologies du mouvement.

Some movement disorders can be treated successfully by surgical procedures such as chronic deep brain stimulation of the subthalamic nucleus, the thalamus or the globus pallidus, as well as lesioning techniques of thalamotomy and pallidotomy, radiosurgical treatment with the Gamma Knife in the thalamus or globus pallidus, and cerebral graft in Parkinson's and Huntington's diseases. The major indications of these surgical techniques are Parkinson's disease, essential tremor, dystonia, Huntington's disease and tremor in multiple sclerosis.

Movement disorder radiosurgery--planning, physics and complication avoidance.

Gamma Knife radiosurgical thalamotomy is an effective and useful alternative to invasive radiofrequency techniques for patients at high surgical risk. The mechanical accuracy of the gamma unit combined with the anatomical accuracy of high-resolution MRI make radiosurgical lesioning safe and precise. Higher radiosurgical doses are more effective than lower ones at eliminating or reducing tremor, and are generally without complications. The results from radiosurgical pallidotomy, as opposed to those of gamma thalamotomy, have been disappointing. A 50% complication rate in the former (homonymous field cuts, hemipareses and dysphagias) combined with a poor success rate has led us to reevaluate the indications for this procedure in the face of the excellent results from radiofrequency pallidotomy with physiological monitoring and deep brain stimulation. Perhaps experience with lowered radiosurgical prescription doses will improve the complication rate. There appears to be a differential sensitivity of the pallidum to radiation, anatomically, than the thalamus. Age-related or anatomy-related susceptible blood supply to the area may lead to hypoxia after singlefraction radiosurgery, in a nuclear complex known to be especially susceptible to hypoxia. In addition, varying levels of iron deposition within the pallidum may catalyze free radical formation in the elderly only to be further exacerbated by tissue hypoxia. Although reported, the success of radiosurgical caudatotomy, subthalamotomy and lesioning of the VL nucleus remains to be further elucidated.

[Unilateral thalamotomy for the treatment of tremor dominant Parkinson's disease]. / Jednostronna talamotomia w leczeniu drzennej postaci choroby Parkinsona.

BACKGROUND AND PURPOSE: To assess the effectiveness of unilateral thalamotomy for the treatment of parkinsonian tremor and other motor signs of Parkinson's disease (PD). MATERIAL AND METHODS: Between 1999 and 2004, 41 patients with idiopathic tremor dominant PD were treated surgically in the Neurosurgical Department of Postgraduate Medical Center in Warsaw. Stereotactic thalamotomy was performed with Leksell stereotactic frame (model G) using intraoperative macrostimulation. The patients were assessed according to the Unified Parkinson's Disease Rating Scale version 3. (UPDRS) before and after thalamotomy in the off state. The progression of PD was also evaluated according to the Hoehn and Yahr scale in the off state and also Schwab and England was used to assess the disability of the patients. The patients were evaluated before thalamotomy in the off state, and 3, 12, 24 and 36 months after surgery, according to the above mentioned clinical rating scales. RESULTS: The authors report their results among 41 patients who underwent stereotactic thalamotomy 3 years postoperatively. At 3 years follow-up (in the group of 19 patients) the contralateral tremor from the presurgical value of 11.2 (items 20 - 21 UPDRS) decreased to 2.6. The rigidity in contralateral limbs at 3 years follow-up was 1.7 (item 22 UPDRS) when compared to 2.8 (item 22 UPDRS) preoperative value. Thalamotomy had no effect on bradykinesia or other manifestations of PD such as balance or gait disturbance. There were 13 transient and 6 permanent complications. CONCLUSIONS: Thalamotomy using intraoperative macrostimulation in carefully selected patients is a beneficial operation for the control of medically refractory parkinsonian resting and postural tremor. The effect of unilateral thalamotomy on tremor is long lasting.

Feed-forward control of post-stroke movement disorders by on-demand type stimulation of the thalamus and motor cortex.

Deep brain stimulation (DBS) of the thalamus (Vo/Vim) has become popular as a means of controlling involuntary movements, including post-stroke movement disorders. We have also found that post-stroke movement disorders and motor weakness can sometimes be controlled by motor cortex stimulation (MCS). In some forms of movement disorders, motor dysfunction becomes evident only when patients intend to move their body. We have developed an on-demand type stimulation system which triggers stimulation by detecting intrinsic signals of intention to move. Such a system represents feed-forward control (FFC) of involuntary movements. We report here our experience of DBS and MCS for controlling post-stroke movement disorders, and discuss the value of FFC. Excellent control of post-stroke movement disorders was achieved by conventional DBS and/or MCS in 20 of 28 patients with hemichoreoathetosis, hemiballism tremor, and motor weakness. FFC was tested in 6 patients who demonstrated excellent control of post-stroke postural tremor or motor weakness by conventional DBS or MCS. The on-demand stimulation provided satisfactory FFC in 4 of 4 patients with postural tremor and 2 of 2 patients with motor weakness, when the activity of muscles involved in posturing or intention to move was fed into the system. These findings justify further clinical studies on DBS and MCS in patients with post-stroke movement disorders. The on-demand type stimulation system may also be useful for overcoming various post-stroke movement disorders.

Electrocardiogram artifacts caused by deep brain stimulation.

BACKGROUND: Deep brain stimulation (DBS) is increasingly used to treat a variety of neurological conditions (e.g. movement disorders and chronic pain). This prospective study was designed to detect electrocardiogram (ECG) artifacts induced by deep brain stimulation and to investigate which factors (patient disease, electrode position within the brain or type of stimulation) produced these artifacts. METHODS: Twelve patients (four women, eight men) with deep brain stimulators were enrolled in the study. Patients were selected to represent the common indications for DBS (Parkinson's disease, tremor, dystonia), the common electrode locations (pallidum, thalamus, subthalamic nucleus) and the two types of stimulation (monopolar, bipolar). Patients had one ECG with the DBS turned 'on' and another with the DBS turned 'off'. The ECGs were then randomized and read by a cardiologist blinded to the status of the patient and DBS and artifacts were noted to be either present or absent. RESULTS: The six patients using monopolar stimulation all had artifacts on their electrocardiograms. These artifacts were severe enough to interfere with ECG interpretation. There were no artifacts detected in the six patients using bipolar stimulation. Electrode location and patient disease appeared to have no effect on ECG artifact. CONCLUSIONS: Deep brain stimulation can cause ECG artifacts when monopolar settings are used. These artifacts are not present with bipolar settings or when the DBS is turned 'off'. Knowledge of these potential ECG artifacts and how to avoid them is essential to facilitate accurate ECG interpretation.