Robot-assisted stereotactic biopsy of pediatric brainstem and thalamic lesions.

OBJECTIVE: Biopsies of tumors located in deep midline structures require highly accurate stereotaxy to safely obtain lesional tissue suitable for molecular and histological analysis. Versatile platforms are needed to meet a broad range of technical requirements and surgeon preferences. The authors present their institutional experience with the robotic stereotactic assistance (ROSA) system in a series of robot-assisted biopsies of pediatric brainstem and thalamic tumors. METHODS: A retrospective analysis was performed of 22 consecutive patients who underwent 23 stereotactic biopsies of brainstem or thalamic lesions using the ROSA platform at Rady Children's Hospital in San Diego between December 2015 and January 2020. RESULTS: The ROSA platform enabled rapid acquisition of lesional tissue across various combinations of approaches, registration techniques, and positioning. No permanent deficits, major adverse outcomes, or deaths were encountered. One patient experienced temporary cranial neuropathy, and 3 developed small asymptomatic hematomas. The diagnostic success rate of the ROSA system was 91.3%. CONCLUSIONS: Robot-assisted stereotactic biopsy of these lesions may be safely performed using the ROSA platform. This experience comprises the largest clinical series to date dedicated to robot-assisted biopsies of brainstem and diencephalic tumors.

Dejerine-Roussy syndrome from thalamic metastasis treated with stereotactic radiosurgery.

Dejerine-Roussy syndrome (central thalamic pain) is associated with damage to the ventral posterior sensory nuclei of the thalamus. We report a patient with breast cancer who developed contralateral hemibody paresthesias and dysesthesias. MR imaging revealed limited volume intracranial metastatic disease including a right posterior thalamic lesion. Stereotactic radiosurgery was utilized to selectively treat the lesion while preserving the remaining thalamus. Two months following treatment, the patient reported vastly improved to complete resolution of her sensory symptoms. This is the first reported case of thalamic tumor directed radiosurgical treatment leading to resolution of central neuropathic pain.

Novel Anatomic Classification of Spontaneous Thalamic Hemorrhage Classified by Vascular Territory of Thalamus.

BACKGROUND: Spontaneous thalamic hemorrhage has increased in incidence in recent years. Analysis of the characteristics of thalamic hemorrhage was based on the vascular territories of the thalamus. METHODS: Retrospective analysis included 303 consecutive patients with spontaneous thalamic hemorrhage. Thalamic hemorrhage was classified into 4 types: anterior type (supplied mainly by the tuberothalamic artery), medial (mainly paramedian thalamic-subthalamic artery), lateral (mainly thalamogeniculate artery), and posterior (mainly posterior choroidal artery). The baseline characteristics, complications, and functional outcomes were assessed. RESULTS: The anterior type was found in 10 patients (3.3%), the medial type in 47 (15.5%), the lateral type in 230 (75.9%), and the posterior type in 16 (5.3%). Intracerebral hemorrhage volume was smallest in the anterior type, and significantly smaller than in the medial (P = 0.002) and lateral types (P < 0.001). Intraventricular hemorrhage (IVH) or acute hydrocephalus was significantly associated with the medial type (P < 0.01 or P < 0.01, respectively). Non-IVH or non-acute hydrocephalus was significantly associated with the anterior (P < 0.05 or P < 0.05, respectively) and lateral (P < 0.05 or P < 0.05, respectively) types. Emergency surgery was correlated only with the medial type (P < 0.01). The independent predictors of poor outcome were age (odds ratio [OR], 1.07; P = 0.002), admission National Institutes of Health Stroke Scale score (OR, 1.32; P < 0.001), and type of thalamic hemorrhage (OR, 2.08; P = 0.038). CONCLUSIONS: The present study proposed a novel anatomic classification of thalamic hemorrhage according to the major thalamic vascular territories.

[A 39 years old woman responding to modafinil with bilateral hypothalamic lesion associated with hyperthermia and hypersomnia: a case report].

A 39 years old woman was admitted to our hospital with a status epilepticus, with high fever of 41°C. Magnetic resonance Imaging (MRI) revealed high signal intensities of both sides of thalami and hypothalami in T2 weighted and fluid attenuated inversion recovery (FLAIR) images. A needle biopsy of the thalamic lesion was consistent with neuromyelitis optica spectrum disorder although her serum antibody to aquaporin-4 was negative. The level of orexin in celebrospinal fluid (CSF) was reduced. She presented hypersomnia, which didn't improve even after intravenous methylprednisolone 1 g daily for 3 days. Administration of oral modafinil extended her waking time. There is a number of reports about neuromyelitis optica (NMO) with hypothalamic lesions. We report this case as important suggestion of treatment of these cases.

Deep brain stimulation of the ventral striatum/anterior limb of the internal capsule in thalamic pain syndrome: study protocol for a pilot randomized controlled trial.

BACKGROUND: Chronic neuropathic pain in thalamic pain syndrome remains intractable. Its poor response is ascribed to destruction of the integrated neuromatrix in experience of pain. Deep brain stimulation is a promising technique to modulate activity of implicated structures. However, traditional approaches targeting sensori-motor substrates have failed to affect disability. The offending lesion in thalamic pain syndrome that almost invariably destroys sensory pain pathways may render these classical approaches ineffective. Instead, we hypothesize that targeting structures representing emotion and affective behavior-ventral striatum/anterior limb of the internal capsule, may alleviate disability. METHODS/DESIGN: We present the design of our phase I randomized, double-blinded, sham-controlled, crossover trial that examines safety, feasibility and efficacy of our proposed approach. In our ongoing trial, we intend to enroll ten patients with thalamic pain syndrome. Following implantation, patients are randomized to receive active deep brain stimulation to the ventral striatum/anterior limb of the internal capsule or sham for 3 months, after which they are crossed over. The primary endpoint is Pain Disability Index. Other outcomes include visual analog scale, depression and anxiety inventories, quality of life, and functional neuroimaging. DISCUSSION: Designing trials of deep brain stimulation for pain is challenging owing to the ethical-scientific dilemma of introducing a control arm, complicated blinding, heterogeneous etiologies, patient expectations, and inadequate assessment of disability. The quality of evidence in the field is classified as level III (poor) because it mainly includes a multitude of uncontrolled case series reporting variable outcomes, with little regard for the placebo effect related to implantation. Without valid data on efficacy, use of deep brain stimulation for pain remains "off label". We present our trial design to discuss feasibility of conducting sham-controlled phase I studies that may represent significant refinement for the field. Double-blinding would reduce influence of patient expectations and therapeutic confusion amongst investigators. With a cross-over approach, the dilemma regarding including a control group can be mitigated. Use of homogeneous etiology, measurement of disability, depression and quality of life, besides pain perception, all represent strategies to evaluate efficacy rigorously. Functional imaging would serve to define mechanisms underlying observed effects and may help optimize future targeting. TRIAL REGISTRATION: Clinicaltrials.gov NCT01072656.

Thalamic metabolic abnormalities in patients with Huntington's disease measured by magnetic resonance spectroscopy

Huntington's disease (HD) is a neurologic disorder that is not completely understood; its fundamental physiological mechanisms and chemical effects remain somewhat unclear. Among these uncertainties, we can highlight information about the concentrations of brain metabolites, which have been widely discussed. Concentration differences in affected, compared to healthy, individuals could lead to the development of useful tools for evaluating the progression of disease, or to the advance of investigations of different/alternative treatments. The aim of this study was to compare the thalamic concentration of metabolites in HD patients and healthy individuals using magnetic resonance spectroscopy. We used a 2.0-Tesla magnetic field, repetition time of 1500 ms, and echo time of 135 ms. Spectra from 40 adult HD patients and 26 control subjects were compared. Quantitative analysis was performed using the LCModel method. There were statistically significant differences between HD patients and controls in the concentrations of N-acetylaspartate+N-acetylaspartylglutamate (NAA+NAAG; t-test, P<0.001), and glycerophosphocholine+phosphocholine (GPC+PCh; t-test, P=0.001) relative to creatine+phosphocreatine (Cr+PCr). The NAA+NAAG/Cr+PCr ratio was decreased by 9% and GPC+PCh/Cr+PCr increased by 17% in patients compared with controls. There were no correlations between the concentration ratios and clinical features. Although these results could be caused by T1 and T2 changes, rather than variations in metabolite concentrations given the short repetition time and long echo time values used, our findings point to thalamic dysfunction, corroborating prior evidence.

Surgical treatment and long-term outcomes of thalamic cavernous malformations.

OBJECTIVE: Resection of thalamic cavernous malformations (CMs) is controversial. The goals of this study were to evaluate the outcome of thalamic CMs after surgical resection, assess predictors of prognosis, and review the literature. METHODS: The authors used the modified Rankin scale (mRS) to retrospectively evaluate the presentation, surgery, and outcomes of 27 consecutive patients who underwent thalamic CMs microresection using six different approaches between 1998 and 2010. RESULTS: Forty-eight hemorrhages occurred in 27 patients (13 men, 14 women; mean age 33.9 years) with a preoperative mRS score of 2.6 ± 1.0 and a preoperative bleeding rate per patient year of 5.2%. Complete resection was achieved in 26 patients (96.3%) without surgical mortality. The postoperative mRS score at discharge was 1.9 ± 1.0. One lesion rebled 1 month after complete surgical resection. After a mean follow-up duration of 48.7 ± 43.2 months, the mean mRS score was 1.2 ± 1.2 and the postoperative rebleeding rate was 0.91% per patient-year. With regard to neurological function, 81.5% of patients improved, 11.1% stabilized, and 7.4% worsened. Good outcomes (mRS score ≤2, living independently) were achieved in 21 patients (77.8%). Long-term surgical morbidity was observed in five patients (18.2%). A multivariate logistic regression analysis identified age (<40 years) as the only predictor of the postoperative mRS score (≤ 2) (odds ratio, 1.24, 95% confidence interval, 1.02-1.52; P = 0.035). CONCLUSIONS: To our knowledge, this is the largest case series reported in the literature to date. Patients with thalamic CMs can obtain a favorable prognosis using microsurgery; an appropriate microsurgical approach contributes to an excellent outcome.

Current differential diagnoses and treatment options of vascular occlusions presenting as bilateral thalamic infarcts: a review of the literature.

bilateral thalamic infarctions are rare and usually caused by vascular occlusions. When symptomatic, it is important to make a distinction between different vascular etiologies in order to provide an effective and timely therapeutic response. Clinical presentations may not adequately differentiate between the vascular etiologies alone. It is therefore important to use imaging technologies to distinguish appropriately the origin of the infarct so that proper treatment can be administered. Advanced imaging techniques, such as CT angiography and MR angiography, have proved useful for distinguishing between arterial and venous causes of bithalamic infarctions. Bilateral thalamic venous infarctions can be treated with anticoagulation medication and with thrombolysis in more severe cases. Bilateral thalamic arterial infarctions may be treated with thrombolysis.

Vivax malaria: a rare cause of thalamic bleed.

Most common cause of thalamic bleed is hypertension; other causes are arteriovenous malformation, aneurysm, bleeding diathesis, drugs, amyloid angiopathy, tumor etc. We present a case of Plasmodium vivax (P. vivax) malaria with unusual site of bleeding i.e. left thalamus of brain. To the best of our knowledge, this is the first reported case of thalamic bleed caused by vivax malaria in absence of severe thrombocytopenia/disseminated intravascular coagulation (DIC).

Bilateral paramedian thalamic infarction with hypothalamic dysfunction.

Unilateral thalamic lesions cause transient or permanent behavioral, sensory and oculomotor disturbances; bilateral lesions of thalamus result in more severe and longer lasting symptoms. We present an atypical case of bilateral paramedian thalamic infarct with concomitant hypothalamic dysfunction. The only risk factor of ischaemic stroke found in the patient was a short lasting episode of atrial fibrillation. Bilateral paramedian thalamic infarcts may result from occlusion of one paramedian thalamic artery, which arises from the posterior cerebral artery, either with separated or with a common trunk, thus supplying the thalamus bilaterally. Independently of anatomical variants of thalamus blood supply, the most probable cause of infarct in our patient was unilateral or bilateral occlusion of the posterior cerebral artery by cardioembolism, probably in the course of basilar artery occlusion. Hypothalamic dysfunction may accompany thalamic infarcts; thus hypothalamo-pituitary function should be routinely assessed in bithalamic infarcts.

Gamma Knife surgery for basal ganglia and thalamic arteriovenous malformations.

OBJECT: Gamma Knife surgery (GKS) has emerged as the treatment of choice for small- to medium-sized cerebral arteriovenous malformations (AVMs) in deep locations. The present study aims to investigate the outcomes of GKS for AVMs in the basal ganglia and thalamus. METHODS: Between 1989 and 2007, 85 patients with AVMs in the basal ganglia and 97 in the thalamus underwent GKS and were followed up for more than 2 years. The nidus volumes ranged from 0.1 to 29.4 cm(3) (mean 3.4 cm(3)). The mean margin dose at the initial GKS was 21.3 Gy (range 10-28 Gy). Thirty-six patients underwent repeat GKS for residual AVMs at a median 4 years after initial GKS. The mean margin dose at repeat GKS was 21.1 Gy (range 7.5-27 Gy). RESULTS: Following a single GKS, total obliteration of the nidus was confirmed on angiograms in 91 patients (50%). In 12 patients (6.6%) a subtotal obliteration was achieved. No flow voids were observed on MR imaging in 14 patients (7.7%). Following single or repeat GKS, total obliteration was angiographically confirmed in 106 patients (58.2%) and subtotal obliteration in 8 patients (4.4%). No flow voids on MR imaging were observed in 18 patients (9.9%). The overall obliteration rates following one or multiple GKSs based on MR imaging or angiography was 68%. A small nidus volume, high margin dose, low number of isocenters, and no history of embolization were significantly associated with an increased rate of obliteration. Twenty-one patients experienced 25 episodes of hemorrhage in 850 risk-years following GKS, yielding an annual hemorrhage rate of 2.9%. Four patients died in this series: 2 due to complications of hemorrhage and 2 due to unrelated diseases. Permanent neurological deficits caused by radiation were noted in 9 patients (4.9%). CONCLUSIONS: Gamma Knife surgery offers a reasonable chance of obliterating basal ganglia and thalamic AVMs and does so with a low risk of complications. It is an optimal treatment option in patients for whom the anticipated risk of microsurgery is too high.

[Neuroepithelial thalamo-mesencephalic cyst]. / Kyste neuroépithélial thalamo-mésencéphalique.

Thalamo-mesencephalic neuroepithelial cysts are rare lesions of the central nervous system. They are thought to arise from neuroectoderm and are also referred to as ependymal cysts due to their origin. It can remain asymptomatic throughout life or rarely can cause symptoms. We describe a 42-year-old woman who presented with thalamic syndrome due to a neuroepithelial cyst of the thalamo-midbrain. Differential diagnosis is made with other cystic lesions in the brain. However a good analysis of imaging feature led to diagnosis. When the lesion is symptomatic, mini-invasive procedure is indicated.

Imaging bithalamic pathology in the pediatric brain: demystifying a diagnostic conundrum.

OBJECTIVE: The thalami are subject to multiple insults including metabolic and toxic phenomena, acute demyelination, infection, infarction, hemorrhage and neoplastic involvement. The purpose of this article is to review the neuroimaging approach, classification, and imaging of bilateral thalamic lesions with histopathology correlation and application of advanced techniques. CONCLUSION: Neuroimaging of abnormal pediatric thalami uses conventional MRI sequences and advanced techniques to characterize lesions. Although there is considerable imaging overlap, a tailored approach can facilitate diagnosis and management.

Thalamic atrophy associated with painful osteoarthritis of the hip is reversible after arthroplasty: a longitudinal voxel-based morphometric study.

OBJECTIVE: Voxel-based morphometry (VBM) is a method of assessing brain gray matter volume that has previously been applied to various chronic pain conditions. From this previous work, it appears that chronic pain is associated with altered brain morphology. The present study was undertaken to assess these potential alterations in patients with painful hip osteoarthritis (OA). METHODS: We studied 16 patients with unilateral right-sided hip pain, before and 9 months after hip arthroplasty. This enabled comparison of gray matter volume in patients with chronic musculoskeletal pain versus healthy controls, as well as identification of any changes in volume following alleviation of pain (after surgery). Assessment involved self-completion questionnaires to assess pain, function, and psychosocial variables, and magnetic resonance imaging scanning of the brain for VBM analysis. RESULTS: Significant differences in brain gray matter volume between healthy controls and patients with painful hip arthritis were seen. Specifically, areas of the thalamus in patients with chronic OA pain exhibited decreased gray matter volume. Furthermore, when these preoperative changes were compared with the brain morphology of the patients 9 months after surgery, the areas of reduced thalamic gray matter volume were found to have "reversed" to levels seen in healthy controls. CONCLUSION: Our findings confirm that gray matter volume decreases within the left thalamus in the presence of chronic pain and disability in patients with hip OA. The results also show that these thalamic volume changes reverse after hip arthroplasty and are associated with decreased pain and increased function. These findings have potential implications with regard to optimizing the timing of orthopedic interventions such as arthroplasty.