Zona incerta

Zona incerta

The zona incerta is a horizontally elongated region of gray matter cells in the subthalamus below the thalamus. Its connections project extensively over the brain from the cerebral cortex down into the spinal cord.

Its function is unknown, though several potential functions related to “limbic–motor integration” have been proposed, such as controlling visceral activity and pain; gating sensory input and synchronizing cortical and subcortical brain rhythms. Its dysfunction may play a role in central pain syndrome. It has also been identified as a promising deep brain stimulation therapy target for treating Parkinsons Disease.

The existence of the zona incerta was first described by Auguste Forel in 1877 as a “region of which nothing certain can be said”.

A hundred and thirty years later in 2007, Nadia Urbain and Martin Deschênes of Université Laval noted that the “zona incerta is among the least studied regions of the brain; its name does not even appear in the index of many textbooks.


Noninvasive detection of the ZI and surrounding region could be critical to further our understanding of this widely connected but poorly understood deep brain region and could contribute to the development and optimization of neuromodulatory therapies.

Lau et al. demonstrated that high resolution (submillimetric) longitudinal (T1) relaxometry measurements at high magnetic field strength (7 T) can be used to delineate the ZI from surrounding white matter structures, specifically the fasciculus cerebellothalamicus, fields of Forel (fasciculus lenticularis, fasciculus thalamicus, and field H), and medial lemniscus. Using this approach, they successfully derived in vivo estimates of the size, shape, location, and tissue characteristics of substructures in the ZI region, confirming observations only previously possible through histological evaluation that this region is not just a space between structures but contains distinct morphological entities that should be considered separately. Our findings pave the way for increasingly detailed in vivo study and provide a structural foundation for precise functional and neuromodulatory investigation 1).

Zona incerta stimulation

see Zona incerta stimulation.

1)

Lau JC, Xiao Y, Haast RAM, et al. Direct visualization and characterization of the human zona incerta and surrounding structures [published online ahead of print, 2020 Jul 17]. Hum Brain Mapp. 2020;10.1002/hbm.25137. doi:10.1002/hbm.25137

Moyamoya Disease Epidemiology outside of Asia

Moyamoya Disease Epidemiology outside of Asia

Studies from outside of Asia are rare. In Washington state and California, the incidence of MMD was reported to be 0.086/100,000 based on 298 patients. The incidence was the highest in Asians, followed by Blacks, Whites, and Hispanics. The incidence in Asian Americans was 4.6 times higher than that in Whites. Female preponderance was also noted 1).

African-Americans had an earlier disease onset with a median age of 18. However, a more recent study based on the Nationwide Inpatient Sample database reported that MMD appears to be distributed among the races according to their relative proportions in the USA population 2).

From 2005 to 2008, there were an estimated 7,473 (2,236 pediatric and 5,237 adult) patients admitted with a diagnosis of MMD in the USA. MMD patients were most frequently Caucasians. Overall, ischemic stroke was the most common reason for admission in both children and adults. Hemorrhagic stroke was more frequent in adults compared with children, and there was a bimodal age distribution with peaks in the first and fourth decades of life. Female-to-male ratio was 2.2. Thus, MMD in the USA does not seem to differ from East Asian MMD.


The incidence of Moyamoya disease (MMD) in Europe is not well known. In those affected, the risk of brain hemorrhage is considered low. A study of Birkeland et al. aimed to investigate the incidence and clinical presentation of MMD in the Danish population.

Eligible patients were identified in the Danish National Patient Register from 1994 to 2017. They collected clinical and radiological data from individual patient records from neurological, neurosurgical, and pediatric units across Denmark. The diagnosis was validated according to established criteria. They also extracted basic demographic data on the cohort from the Danish Civil Registration System.

A total of 52 patients fulfilled the diagnostic criteria for MMD. Most cases were native Danes and only 15% of cases had an East Asian background. The ratio of female to male patients was 1.8, and the incidence had two peaks: one in childhood and another in young middle age. Until 2007, MMD was only diagnosed sporadically. From 2008 onwards, the incidence rate was 0.07 per 100 000 person-years (95% confidence interval 0.05-0.09 per 100 000 person-years). The most common mode of presentation was ischemic stroke (33%), followed by hemorrhage (23%), headache (17%), and transient ischemic attack (14%).

MMD is rare in Denmark, but associated with a considerable risk of hemorrhage. Thus, MMD should be considered in the workup for ischemic as well as hemorrhagic stroke in children and middle-aged Caucasian3).

References

1)

Uchino K, Johnston SC, Becker KJ, Tirschwell DL. Moyamoya disease in Washington State and California. Neurology. 2005;65(6):956-958. doi:10.1212/01.wnl.0000176066.33797.82
2)

Kainth D, Chaudhry SA, Kainth H, Suri FK, Qureshi AI. Epidemiological and clinical features of moyamoya disease in the USA. Neuroepidemiology. 2013;40(4):282-287. doi:10.1159/000345957
3)

Birkeland P, Tharmabalan V, Lauritsen J, Ganesan V, Bjarkam CR, von Weitzel-Mudersbach P. Moyamoya disease in a european setting: A danish population-based study [published online ahead of print, 2020 Jul 15]. Eur J Neurol. 2020;10.1111/ene.14439. doi:10.1111/ene.14439

Intraoperative Ultrasound for Spine Surgery

Intraoperative Ultrasound for Spine Surgery

Accurate and efficient registration of pre-operative computed tomography or magnetic resonance images with iUS images are key elements in the success of iUS-based spine navigation. While widely investigated in research, iUS-based spine navigation has not yet been established in the clinic. This is due to several factors including the lack of a standard methodology for the assessment of accuracy, robustness, reliability, and usability of the registration method. To address these issues, Gueziri et al. presented a systematic review of the state-of-the-art techniques for iUS-guided registration in spinal image guided surgery (IGS). The review follows a new taxonomy based on the four steps involved in the surgical workflow that include pre-processing, registration initialization, estimation of the required patient to image transformation, and a visualization process. They provided a detailed analysis of the measurements in terms of accuracy, robustness, reliability, and usability that need to be met during the evaluation of a spinal IGS framework. Although this review is focused on spinal navigation, they expect similar evaluation criteria to be relevant for other IGS applications 1).


Intraoperative ultrasound (iUS) has been applied in spinal surgery for all kinds of diseases 2) 3) ranging from trauma, 4) degenerative diseases, 5) 6) developmental malformations, 7) vascular diseases, 8). to imaging in spinal tumor surgery

Intraoperative Ultrasound for spinal tumor surgery

Intraoperative Ultrasound for spinal tumor surgery

Syringomyelia

Intraoperative ultrasound is often helpful for:

a) localizing the cyst

b) assessing for septations (to avoid shunting only part of cyst)

Controversial,for intramedullary spinal cord tumors 9) favored by some experts. Astrocytomas are usually iso-echoic with the spinal cord, whereas ependymomas are usually hyperechoic.

Transpedicular thoracic discectomy

Intraoperative ultrasound is a simple yet valuable tool for real-time imaging during transpedicular thoracic discectomy. Visualization provided by intraoperative US increases the safety profile of posterior approaches and may make thoracotomy unnecessary in a selected group of patients, especially when a patient has existing pulmonary disease or is otherwise not medically fit for the transthoracic approach 10) 11).

References

1)

Gueziri HE, Santaguida C, Collins DL. The state-of-the-art in ultrasound-guided spine interventions [published online ahead of print, 2020 Jun 26]. Med Image Anal. 2020;65:101769. doi:10.1016/j.media.2020.101769
2)

Ganau M, Syrmos N, Martin AR, Jiang F, Fehlings MG. Intraoperative ultrasound in spine surgery: history, current applications, future developments. Quant Imaging Med Surg. 2018;8: 261-267.
3)

Vasudeva VS, Abd-El-Barr M, Pompeu YA, Karhade A, Groff MW, Lu Y. Use of intraoperative ultrasound during spinal surgery. Glob Spine J. 2017;7:648-656.
4)

Meinig H, Doffert J, Linz N, Konerding MA, Gercek E, Pitzen T. Sensitivity and specificity of ultrasound in spinal trauma in 29 consecutive patients. Eur Spine J. 2015;24:864-870.
5)

Nishimura Y, Thani NB, Tochigi S, Ahn H, Ginsberg HJ. Thoracic discectomy by posterior pedicle-sparing, transfacet approach with realtime intraoperative ultrasonography: clinical article. J Neurosurg Spine. 2014;21:568-576.
6)

Goodkin R, Haynor DR, Kliot M. Intraoperative ultrasound for monitoring anterior cervical vertebrectomy. Technical note. J Neurosurg. 1996;84: 702-704.
7)

. Cui LG, Jiang L, Zhang HB, et al. Monitoring of cerebrospinal fluid flow by intraoperative ultrasound in patients with Chiari I malformation. Clin Neurol Neurosurg. 2011;113:173-176.
8)

Prada F, Del Bene M, Farago G, DiMeco F. Spinal dural arteriovenous fistula: is there a role for intraoperative contrast-enhanced ultrasound? World Neurosurg. 2017;100:712.e15-712.e18.
9)

Albright AL. Pediatric Intramedullary Spinal Cord Tumors. Childs Nerv Syst. 1999; 15:436–437
10)

Tan LA, Lopes DK, Fontes RB. Ultrasound-guided posterolateral approach for midline calcified thoracic disc herniation. J Korean Neurosurg Soc. 2014 Jun;55(6):383-6. doi: 10.3340/jkns.2014.55.6.383. Epub 2014 Jun 30. PubMed PMID:25237439.
11)

Nishimura Y, Thani NB, Tochigi S, Ahn H, Ginsberg HJ. Thoracic discectomy by posterior pedicle-sparing, transfacet approach with real-time intraoperative ultrasonography. J Neurosurg Spine. 2014 Jul 18:1-9. [Epub ahead of print] PubMed PMID: 25036220.
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