Four-tract probabilistic tractography technique for target selection in essential tremor treatment with magnetic resonance-guided focused ultrasound.

OBJECTIVES: Magnetic resonance-guided focused ultrasound (MRgFUS) thalamotomy is a novel, minimally invasive ablative treatment for essential tremor (ET). The use of a four-tract probabilistic tractography technique, targeting the intersection between the dentato-rubro-thalamic tracts (both decussating and non-decussating), while evaluating the corticospinal tract and the medial lemniscus, may obtain immediate clinical results with reduced adverse events. Our aim is to present our experience with the four-tract technique for patients undergoing ET treatment with MRgFUS. METHODS: Retrospective analysis of a prospective database of consecutive patients undergoing ET treatment in a single center from February 2022 to February 2023. Procedural parameters were collected, and tremor improvement was assessed with the Clinical Rating Scale for Tremor (CRST) at baseline and at 3 and 6 months. Adverse events were also reported. RESULTS: Forty-three patients (median age, 72 years [interquartile range, 66-76]; 22 females) were evaluated. Tremor improved significatively in all CRST subsections at 3 months, including the CRST part A + B treated hand tremor (22 [19-27] vs 4 [2-7], p < 0.001) and CRST part C (16 [13-19] vs 3 [1-4], p < 0.001). Differences persisted significant at 6 months. Adverse events were few (4.1% of paresthesias and 12.5% of objective gait disturbance at follow-up) and recorded as mild. The median number of sonications was 7 [6-8] and mean operative time 68.7 ± 24.2 min. CONCLUSION: Our data show support for the feasibility and benefits of systematic targeting approach with four-tract probabilistic tractography for treating ET using MRgFUS. CLINICAL RELEVANCE STATEMENT: An approach with four-tract probabilistic tractography for treating essential tremor (ET) patients with magnetic resonance-guided focused ultrasound decreases interindividual variability with good clinical outcomes, low number of sonications, few adverse effects, and short procedure times. KEY POINTS: • The optimal target for the treatment of essential tremor with MR-guided focused ultrasound remains unknown. • Four-tract probabilistic tractography is a feasible technique that reduces interindividual variability, with good clinical results, few side effects, and short operative time. • The four-tract tractography approach can be performed using different MRI scanners and post-processing software in comparison with the initial description of the technique.

[Lipomatous ependymomas of the posterior fossa. An infrequent and little-known subtype. A case report and review of the literature]. / Ependimomas lipomatosos de la fosa posterior. Un subtipo muy infrecuente y poco conocido. Presentación de caso y revisión de la literatura.

Ependymomas are well defined glial tumours composed of uniform small cells with round nuclei in a fibrillar matrix. They have characteristic perivascular acellular areas (pseudorosettes) and, in some cases, ependymal rosettes. The three most well-known histological phenotypes are papillary, clear-cell and tanycytic. The WHO classification includes rare cases of ependymoma with lipomatous metaplasia. Lipomatous ependymomas of the posterior fossa are extremely rare; we only found 7reports of cases in adults. They usually arise in the fourth ventricle and may extend into the cerebellum, when they often show extensive vacuolization, pushing the nucleus to the periphery and giving rise to a signet-ring cell appearance. Radiologically, there are few findings characteristic of these tumours. Immunohistochemistry is essential to differentiate this subtype from other more common lesions, such as metastatic adenocarcinoma, especially from breast, intestine and kidney.

Ependimomas lipomatosos de la fosa posterior. Un subtipo muy infrecuente y poco conocido. Presentación de caso y revisión de la literatura / Lipomatous ependymomas of the posterior fossa. An infrequent and little-known subtype. A case report and review of the literature

Los ependimomas son tumores gliales bien circunscritos compuestos de células pequeñas uniformes con un núcleo redondo en una matriz fibrilar. Se caracterizan por zonas anucleadas perivasculares (pseudorrosetas) y, en algunos casos, rosetas ependimarias. Tres fenotipos histológicos son los más reconocidos: papilar, de células claras y tanicítico. La OMS reconoce casos raros de ependimomas con metaplasia lipomatosa. Los ependimomas lipomatosos de fosa posterior son extremadamente infrecuentes, y en nuestra búsqueda hemos encontrado 7casos reportados en la literatura (excluyendo niños). Se originan habitualmente del 4.° ventrículo y podrían presentar extensión cerebelosa. Estos suelen presentar extensa vacuolización empujando el núcleo a la periferia y simulando la apariencia de «signet-ring cells» (células en anillo de sello). Radiológicamente hay pocos hallazgos que sean característicos de este tipo de tumores. La inmunohistoquímica es decisiva para no confundir esta variante con lesiones más comunes, como el adenocarcinoma metastásico, especialmente los de mama, intestino y renal.(AU)

Ependymomas are well defined glial tumours composed of uniform small cells with round nuclei in a fibrillar matrix. They have characteristic perivascular acellular areas (pseudorosettes) and, in some cases, ependymal rosettes. The three most well-known histological phenotypes are papillary, clear-cell and tanycytic. The WHO classification includes rare cases of ependymoma with lipomatous metaplasia. Lipomatous ependymomas of the posterior fossa are extremely rare; we only found 7reports of cases in adults. They usually arise in the fourth ventricle and may extend into the cerebellum, when they often show extensive vacuolization, pushing the nucleus to the periphery and giving rise to a signet-ring cell appearance. Radiologically, there are few findings characteristic of these tumours. Immunohistochemistry is essential to differentiate this subtype from other more common lesions, such as metastatic adenocarcinoma, especially from breast, intestine and kidney.(AU)

Are We Ready for Cell Therapy to Treat Stroke?

Clinical trials of cell therapies that target stroke started at the beginning of this century and they have experienced a significant boost in recent years as a result of promising data from basic research studies. The increase in the information available has paved the way to carry out more innovative and varied human studies. Efforts have focused on the search for a safe and effective treatment to stimulate neuro-regeneration in the brain and to reduce the sequelae of stroke in patients. Therefore, this review aims to evaluate the clinical trials using cell therapy to treat stroke published to date and assess their limitations. From 2000 to date, most of the published clinical trials have focused on phases I or II, and the vast majority of them demonstrate that stem cells are essentially safe to use when administered by different routes, with transient and mild adverse events that do not generally have severe consequences for health. In general, there is considerable variation in the trials in terms of statistical design, sample size, the cells used, the routes of administration, and the functional assessments (both at baseline and follow-up), making it difficult to compare the studies. From this general description, possibly the experimental protocol is the main element to improve in future studies. Establishing an adequate experimental and statistical design will be essential to obtain favorable and reliable results when conducting phase III clinical trials. Thus, it is necessary to standardize the criteria used in these clinical trials in order to aid comparison. Shortly, cell therapy will be a key approach in the treatment of stroke if adequate and comprehensive levels of recovery are to be achieved.

Brown-Séquard syndrome and cervical post-traumatic subarachnoid hematoma / Síndrome de Brown-Séquard y hematoma subaracnoideo espinal cervical postraumático

Cervical Traumatic SSH are very rare in literature. They are usually caused by cardiopulmonary diseases that increase vascular pressure causing spinal vessels rupture. In thoracolumbar spine, the spinal puncture is the most common cause. The ventrolateral position is even more unusual. In traumatic brain injury (TBI), an abrupt extension-flexion movement could have caused the rupture of subarachnoid vessels. This, accompanied by the slowed blood "wash out" (probably due to the previous osteoarthrosis and spinal canal stenosis), led to the formation of an organized clot, which caused an acute spinal cord compression syndrome. Cervical subarachnoid spinal hematoma can present as Brown-Séquard syndrome. The treatment is prompt surgical removal and decompression. The posterior approach (partial hemilaminectomy with or without laminoplasty) with microsurgical technique is feasible, fast and simple to evacuate the hematoma with good results. Surgical nuances in posterior approach are: small spinal canal, difficulty in mobilizing the cervical cord, these haematomas are wrapped and attached to the spinal cord or nerve roots by multiple arachnoid bands, requiring techniques of Microdissection for its evacuation unlike the epidural and subdural haematomas that are easily aspirated. Here, we report a unique case of a ventrolateral SSH due to TBI

Los hematomas subaracnoideos espinales cervicales postraumáticos son muy infrecuentes en la literatura. Generalmente son causados por enfermedades cardiopulmonares que incrementan la presión vascular y producen la rotura de los vasos espinales. En la columna toracolumbar la causa más frecuente es la punción lumbar. La posición ventrolateral dentro del canal es todavía más inusual. En el traumatismo craneoencefálico, un movimiento súbito de flexoextensión podría causar la rotura de vasos subaracnoideos. Si lo anterior se acompaña de un «lavado» enlentecido de la sangre (probablemente debido a la presencia de osteoartrosis y estenosis de canal), podría llevar a la formación de un coágulo organizado, el cual, si es de gran tamaño, podría causar un síndrome de compresión medular aguda. Los hematomas subaracnoideos espinales cervicales pueden presentarse como un síndrome de Brown-Séquard. El tratamiento en caso de compresión medular aguda es la evacuación del coágulo y la descompresión del canal urgente. El abordaje posterior (hemilaminectomía parcial con o sin laminoplastia) con técnica microquirúrgica es factible, rápido y sencillo para evacuar el hematoma, con buenos resultados. Los matices quirúrgicos en el abordaje posterior son: pequeño canal espinal y dificultad para movilizar la médula cervical. Estos hematomas están envueltos y adheridos a la médula espinal o a las raíces nerviosas por múltiples bandas aracnoideas, requiriendo técnicas de microdisección para su evacuación, a diferencia de los hematomas epidurales y subdurales, que son fácilmente aspirados. Presentamos un caso único de un hematoma subaracnoideo espinal cervical ventrolateral debido a traumatismo craneoencefálico leve

Brown-Séquard syndrome and cervical post-traumatic subarachnoid hematoma.

Cervical Traumatic SSH are very rare in literature. They are usually caused by cardiopulmonary diseases that increase vascular pressure causing spinal vessels rupture. In thoracolumbar spine, the spinal puncture is the most common cause. The ventrolateral position is even more unusual. In traumatic brain injury (TBI), an abrupt extension-flexion movement could have caused the rupture of subarachnoid vessels. This, accompanied by the slowed blood "wash out" (probably due to the previous osteoarthrosis and spinal canal stenosis), led to the formation of an organized clot, which caused an acute spinal cord compression syndrome. Cervical subarachnoid spinal hematoma can present as Brown-Séquard syndrome. The treatment is prompt surgical removal and decompression. The posterior approach (partial hemilaminectomy with or without laminoplasty) with microsurgical technique is feasible, fast and simple to evacuate the hematoma with good results. Surgical nuances in posterior approach are: small spinal canal, difficulty in mobilizing the cervical cord, these haematomas are wrapped and attached to the spinal cord or nerve roots by multiple arachnoid bands, requiring techniques of Microdissection for its evacuation unlike the epidural and subdural haematomas that are easily aspirated. Here, we report a unique case of a ventrolateral SSH due to TBI.