[Essential Tremor That is Difficult to Improve with Standard Medical Treatment-Suppression: Surgical Treatment of Tremor].

Drug-refractory essential tremors, especially those in the upper extremities, may benefit from surgical treatment. Currently, three main treatment methods are available: deep brain stimulation (DBS), radiofrequency coagulation (RF), and magnetic resonance -guided focused ultrasound surgery (MRgFUS). DBS is a device-based therapy, and its effects are reversible, whereas RF and FUS create irreversible coagulation lesions. DBS and RF require the direct puncturing of the target, whereas FUS focuses ultrasound from extracranial sources. The primary target is the ventralis intermedius of the thalamus (Vim); however, the posterior subthalamic area (PSA) is also reportedly an effective target site. In this article, we will summarize the features of the three treatments for essential tremors, and discuss the treatment strategies and methods for each symptom.

Endoscopic Hematoma Evacuation for Intracerebral Hemorrhage Under Local Anesthesia: Factors That Affect the Hematoma Removal Rate.

OBJECTIVE: Recent advances in endoscopic surgery have led to more patients being able to undergo endoscopic removal of hypertensive intracerebral hemorrhage (HICH). However, because of the minimal invasiveness, endoscopic HICH removal through a narrow surgical window can result in a low removal rate. The goal of the present study was to investigate the factors that affect the removal rate of HICH evacuation. METHODS: The data from 28 patients with supratentorial HICH who had undergone endoscopic hematoma evacuation were retrospectively analyzed. The inclusion criteria were spontaneous supratentorial HICH with a hematoma volume >30 mL, admission to the hospital within 24 hours of ictus, and a Glasgow coma scale score of ≥4. RESULTS: Of the 28 patients, 9 were women and 19 were men, ranging in age from 41 to 86 years (mean, 60.7 ± 12.7). The hematoma location was the basal ganglia in 25 patients and subcortical in 3 patients. The mean preoperative hematoma volume was 62.4 ± 22.5 mL. The hematoma removal rate was <60% for 11 patients (poor evacuation group) and ≥60% for in 17 patients (good evacuation group). Comparing the 2 groups, chronic renal failure treated with hemodialysis (P = 0.0072, χ2 test), liver cirrhosis (P = 0.023, χ2 test), and surgeon experience with ≥10 cases of endoscopic HICH removal (P = 0.016, χ2 test) were significant factors related to the HICH removal rate. CONCLUSION: To achieve a good removal rate, surgeons should have experience performing the endoscopic procedure. Also, patients with end-stage chronic renal failure or liver cirrhosis should be excluded.

Efficacy of Fiber Tractography in the Stereotactic Surgery of the Thalamus for Patients with Essential Tremor.

Several targets and targeting methods are utilized in stereotactic surgery to achieve tremor suppression for patients with intractable tremor. Recent developments in magnetic resonance imaging, including diffusion tensor imaging, have enabled the setting of appropriate targets in stereotactic surgery. In this retrospective study, the optimal target to suppress tremors in stereotactic surgery was explored using diffusion tensor image-based fiber tractography. Four tracts were focused on in this study, namely: the cerebello-thalamo-premotor cortical fiber tract, cerebello-thalamo-primary motor cortical fiber tract, spino-thalamo-somatosensory cortical fiber tract, and pyramidal tract. In 10 patients with essential tremor, we evaluated the thalamotomy lesions and active contacts of the lead in thalamic stimulation by diffusion tensor image-based fiber tractography to reveal which part of the cerebral cortex is most affected by stereotactic surgery. Tremor suppression and adverse events were also evaluated in the patients involved in this study. Consequently, the good tremor suppression was achieved in all patients. There had been no permanent adverse events 3 months after surgery. Twelve lesions in thalamotomy patients or active contacts of the lead in thalamic stimulation patients were on the cerebello-thalamo-premotor cortical fiber tract (12/14 lesions or active contacts: 86%). In conclusion, the cerebello-thalamo-premotor cortical fiber tract may be an optimal target for tremor suppression. Diffusion tensor image-based fiber tractography may enable us to both determine the optimal target to achieve strong tremor suppression and to reduce the number of adverse events by keeping lesions or electrodes away from important fiber tracts, such as the pyramidal tract and spinothalamic fibers.

A case of difficult management of fluid-electrolyte imbalance in choroid plexus papilloma.

A 22-month-old boy presented with nausea and gradual deterioration of gait disturbance. Computed tomography (CT) demonstrated an intraventricular mass lesion in the right lateral ventricle. He was referred to our department 3 weeks after onset. Acute hydrocephalus gradually proceeded 4 days after admission, and external ventricular drainage (EVD) was performed. EVD revealed cerebrospinal fluid (CSF) overproduction (800-1,500 mL/day) under constant pressure of 10 cm H2O above external auditory meatus. Magnetic resonance imaging showed a multi-lobular mass in the inferior horn of the right lateral ventricle. A choroid plexus tumor was suspected. The ratio of blood urea nitrogen:creatinine (BUN:Cre) remained between 30 and 40, and hemoglobin was between 14.0-17.0 mg/dL, suggesting marked dehydration. Serum sodium varied between 117 and 140 mmol/L, and serum potassium between 2.2 mmol/L and 6.9 mmol/L. The amount of EVD was unstable and fluid balance management was difficult. Hypotonic fluid with sodium chloride supplement was used to adjust the fluid and electrolyte imbalance. Surgical removal of the tumor was performed 6 days after EVD and tumor was grossly and totally removed. The high BUN:Cre ratio decreased to about 15 and hemoglobin recovered to 7.5-9.0 mg/dL after removal. Electrolytes returned to the normal range. Overproduction of CSF also markedly improved to < 300 mL/day. Histopathological examination diagnosed choroid plexus papilloma.We experienced a case of choroid plexus papilloma associated with fluid-electrolyte imbalance due to over-drainage after EVD, which could not be effectively controlled before tumor removal. Cautious fluid management and emergent surgical resection might be required to manage the overproduction of CSF and fluid-electrolyte imbalance.

Blood flow disturbance in perforating arteries attributable to aneurysm surgery.

OBJECT: The object of this study was to investigate patients with cerebral infarction in the area of the perforating arteries after aneurysm surgery. METHODS: The authors studied the incidence of cerebral infarction in 1043 patients using computed tomography or magnetic resonance imaging and the affected perforating arteries, clinical symptoms, prognosis, and operative maneuvers resulting in blood flow disturbance. RESULTS: Among 46 patients (4.4%) with infarction, the affected perforating arteries were the anterior choroidal artery (AChA) in nine patients, lenticulostriate artery (LSA) in nine patients, hypothalamic artery in two patients, posterior thalamoperforating artery in five patients, perforating artery of the vertebral artery (VA) in three patients, anterior thalamoperforating artery in nine patients, and recurrent artery of Heubner in nine patients. Sequelae persisted in 21 (45.7%) of the 46 patients; 13 (28.3%) had transient symptoms and 12 (26.1%) were asymptomatic. Sequelae developed in all patients with infarctions in perforating arteries in the area of the AChA, hypothalamic artery, or perforating artery of the VA; in four of five patients with posterior thalamoperforating artery involvement; and in two of nine with LSA involvement. The symptoms of anterior thalamoperforating artery infarction or recurrent artery of Heubner infarction were mild and/or transient. The operative maneuvers leading to blood flow disturbance in perforating arteries were aneurysmal neck clipping in 21 patients, temporary occlusion of the parent artery in nine patients, direct injury in seven patients, retraction in five patients, and trapping of the parent artery in four patients. CONCLUSIONS: The patency of the perforating artery cannot be determined by intraoperative microscopic inspection. Intraoperative motor evoked potential monitoring contributed to the detection of blood flow disturbance in the territory of the AChA and LSA.

Confirmation of blood flow in perforating arteries using fluorescein cerebral angiography during aneurysm surgery.

OBJECT: The authors performed fluorescein cerebral angiography in patients after aneurysm clip placement to confirm the patency of the parent artery, perforating artery, and other arteries around the aneurysm. METHODS: Twenty-three patients who underwent aneurysm surgery were studied. Aneurysms were located in the internal carotid artery in 12 patients, middle cerebral artery in six, anterior cerebral artery in three, basilar artery bifurcation in one, and junction of the vertebral artery (VA) and posterior inferior cerebellar artery in one. After aneurysm clip placement, the target arteries were illuminated using a beam from a blue light-emitting diode atop a 7-mm diameter pencil-type probe. In all patients, after intravenous administration of 5 ml of 10% fluorescein sodium, fluorescence in the vessels was clearly observed through a microscope and recorded on videotape. RESULTS: The excellent image quality and spatial resolution of the fluorescein angiography procedure facilitated intraoperative real-time assessment of the patency of the perforating arteries and branches near the aneurysm, including: 12 posterior communicating arteries; 12 anterior choroidal arteries; four lenticulostriate arteries; three recurrent arteries of Heubner; three hypothalamic arteries; one ophthalmic artery; one perforating artery arising from the VA; and one posterior thalamoperforating artery. All 23 patients experienced an uneventful postoperative course without clinical symptoms of perforating artery occlusion. CONCLUSIONS: Because the fluorescein angiography procedure described here allows intraoperative confirmation of the patency of perforating arteries located deep inside the surgical field, it can be practically used for preventing unexpected cerebral infarction during aneurysm surgery.

Thalamic arteriovenous malformation with an unusual draining system--case report.

A 52-year-old man suddenly experienced headache and vomiting. Computed tomography demonstrated a small area of hemorrhage in the right cerebellar hemisphere. Angiography revealed a thalamic arteriovenous malformation (AVM) fed by the bilateral medial posterior choroidal arteries and left marginal tentorial artery, and drained into the confluence via the cerebellar veins without flow into the supratentorial venous system. The draining veins included two varices, one of which, in the right cerebellar hemisphere, was thought to be the source of bleeding. The AVM nidus was removed via the right occipital transtentorial approach. A portion of a drainer adhered to the surface of the great vein of Galen but without opening into the galenic system and all drainers from this thalamic AVM flowed into the infratentorial cerebellar venous system.