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Juxiang Wang, Ke Li, Hongjia Li, Chengyi Ji, Ziyao Wu, Huimin Chen and Bin Chen

OBJECTIVE

Increased intracranial pressure (ICP) results in enlarged optic nerve sheath diameter (ONSD). In this study the authors aimed to assess the association of ONSD and ICP in severe traumatic brain injury (TBI) after decompressive craniotomy (DC).

METHODS

ONSDs were measured by ocular ultrasonography in 40 healthy control adults. ICPs were monitored invasively with a microsensor at 6 hours and 24 hours after DC operation in 35 TBI patients. ONSDs were measured at the same time in these patients. Patients were assigned to 3 groups according to ICP levels, including normal (ICP ≤ 13 mm Hg), mildly elevated (ICP = 14–22 mm Hg), and severely elevated (ICP > 22 mm Hg) groups. ONSDs were compared between healthy control adults and TBI cases with DC. Then, the association of ONSD with ICP was analyzed using Pearson’s correlation coefficient, linear regression analysis, and receiver operator characteristic curves.

RESULTS

Seventy ICP measurements were obtained among 35 TBI patients after DC, including 25, 27, and 18 measurements in the normal, mildly elevated, and severely elevated ICP groups, respectively. Mean ONSDs were 4.09 ± 0.38 mm in the control group and 4.92 ± 0.37, 5.77 ± 0.41, and 6.52 ± 0.44 mm in the normal, mildly elevated, and severely elevated ICP groups, respectively (p < 0.001). A significant linear correlation was found between ONSD and ICP (r = 0.771, p < 0.0001). Enlarged ONSD was a robust predictor of elevated ICP. With an ONSD cutoff of 5.48 mm (ICP > 13 mm Hg), sensitivity and specificity were 91.1% and 88.0%, respectively; a cutoff of 5.83 mm (ICP > 22 mm Hg) yielded sensitivity and specificity of 94.4% and 81.0%, respectively.

CONCLUSIONS

Ultrasonographic ONSD is strongly correlated with invasive ICP measurements and may serve as a sensitive and noninvasive method for detecting elevated ICP in TBI patients after DC.

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San Diego, CA • April 13–17, 2019

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Bawarjan Schatlo, Oliver P. Gautschi, Christoph M. Friedrich, Christian Ebeling, Max Jägersberg, Zsolt Kulscar, Vitor Mendes Pereira, Karl Schaller and Philippe Bijlenga

OBJECTIVE

Although several studies have suggested that the incidence of intracranial aneurysms (IAs) is higher in smokers, the higher prevalence of subarachnoid hemorrhage (SAH) in smokers remains uncertain. It is unclear whether smoking additionally contributes to the formation of multiple aneurysms and the risk of rupture. The aim of this study was to determine whether smoking is associated with IA formation, multiplicity, or rupture.

METHODS

Patients from the prospective multicenter @neurIST database (n = 1410; 985 females [69.9%]) were reviewed for the presence of SAH, multiple aneurysms, and smoking status. The prevalence of smokers in the population of patients diagnosed with at least one IA was compared with that of smokers in the general population.

RESULTS

The proportion of smokers was higher in patients with IAs (56.2%) than in the reference population (51.4%; p < 0.001). A significant association of smoking with the presence of an IA was found throughout group comparisons (p = 0.01). The presence of multiple IAs was also significantly associated with smoking (p = 0.003). A trend was found between duration of smoking and the presence of multiple IAs (p = 0.057). However, the proportion of smokers among patients suffering SAH was similar to that of smokers among patients diagnosed with unruptured IAs (p = 0.48).

CONCLUSIONS

Smoking is strongly associated with IA formation. Once an IA is present, however, smoking does not appear to increase the risk of rupture compared with IAs in the nonsmoking population. The trend toward an association between duration of smoking and the presence of multiple IAs stresses the need for counseling patients with IAs regarding lifestyle modification.

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Issael Ramirez, Paldor Iddo and Sergey Spektor

Cerebral cavernous malformations (CCMs) are known to be angiographically occult malformations with low perfusion of blood flow.5 Near-infrared indocyanine green (ICG) video angiography allows for intraoperative observation and documentation of blood flow in large and small vessels.2,4

Developmental venous anomalies (DVAs) are thought to be the most common cerebral vascular abnormality.2,3 The opportunity to differentiate intraoperatively between normal veins and DVA draining veins might be useful in the event of a possible venous sacrifice. Coagulation of the DVA can lead to devastating consequences. ICG reliably demonstrates margins between CCM and the venous structures.1,2 For these reasons, we decided to use ICG video angiography in this patient.

The video can be found here: https://youtu.be/9MONn0GkO4U.

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Sauson Soldozy, Pedro Norat, Mazin Elsarrag, Ajay Chatrath, John S. Costello, Jennifer D. Sokolowski, Petr Tvrdik, M. Yashar S. Kalani and Min S. Park

The pathogenesis of intracranial aneurysms remains complex and multifactorial. While vascular, genetic, and epidemiological factors play a role, nascent aneurysm formation is believed to be induced by hemodynamic forces. Hemodynamic stresses and vascular insults lead to additional aneurysm and vessel remodeling. Advanced imaging techniques allow us to better define the roles of aneurysm and vessel morphology and hemodynamic parameters, such as wall shear stress, oscillatory shear index, and patterns of flow on aneurysm formation, growth, and rupture. While a complete understanding of the interplay between these hemodynamic variables remains elusive, the authors review the efforts that have been made over the past several decades in an attempt to elucidate the physical and biological interactions that govern aneurysm pathophysiology. Furthermore, the current clinical utility of hemodynamics in predicting aneurysm rupture is discussed.

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Cavernous angiomas: deconstructing a neurosurgical disease

JNSPG 75th Anniversary Invited Review Article

Issam A. Awad and Sean P. Polster

Cavernous angioma (CA) is also known as cavernoma, cavernous hemangioma, and cerebral cavernous malformation (CCM) (National Library of Medicine Medical Subject heading unique ID D006392). In its sporadic form, CA occurs as a solitary hemorrhagic vascular lesion or as clustered lesions associated with a developmental venous anomaly. In its autosomal dominant familial form (Online Mendelian Inheritance in Man #116860), CA is caused by a heterozygous germline loss-of-function mutation in one of three genes—CCM1/KRIT1, CCM2/Malcavernin, and CCM3/PDCD10—causing multifocal lesions throughout the brain and spinal cord.

In this paper, the authors review the cardinal features of CA’s disease pathology and clinical radiological features. They summarize key aspects of CA’s natural history and broad elements of evidence-based management guidelines, including surgery. The authors also discuss evidence of similar genetic defects in sporadic and familial lesions, consequences of CCM gene loss in different tissues at various stages of development, and implications regarding the pathobiology of CAs.

The concept of CA with symptomatic hemorrhage (CASH) is presented as well as its relevance to clinical care and research in the field. Pathobiological mechanisms related to CA include inflammation and immune-mediated processes, angiogenesis and vascular permeability, microbiome driven factors, and lesional anticoagulant domains. These mechanisms have motivated the development of imaging and plasma biomarkers of relevant disease behavior and promising therapeutic targets.

The spectrum of discoveries about CA and their implications endorse CA as a paradigm for deconstructing a neurosurgical disease.

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Rob Molenberg, Marlien W. Aalbers, Jan D. M. Metzemaekers, Aryan Mazuri, Gert-Jan Luijckx, Rob J. M. Groen, Maarten Uyttenboogaart and J. Marc C. van Dijk

OBJECTIVE

Unruptured intracranial aneurysms are common incidental findings on brain imaging. Short-term follow-up for conservatively treated aneurysms is routinely performed in most cerebrovascular centers, although its clinical relevance remains unclear. In this study, the authors assessed the extent of growth as well as the rupture risk during short-term follow-up of conservatively treated unruptured intracranial aneurysms. In addition, the influence of patient-specific and aneurysm-specific factors on growth and rupture risk was investigated.

METHODS

The authors queried their prospective institutional neurovascular registry to identify patients with unruptured intracranial aneurysms and short-term follow-up imaging, defined as follow-up MRA and/or CTA within 3 months to 2 years after initial diagnosis. Medical records and questionnaires were used to acquire baseline information. The authors measured aneurysm size at baseline and at follow-up to detect growth. Rupture was defined as a CT scan–proven and/or CSF-proven subarachnoid hemorrhage (SAH).

RESULTS

A total of 206 consecutive patients with 267 conservatively managed unruptured aneurysms underwent short-term follow-up at the authors’ center. Seven aneurysms (2.6%) enlarged during a median follow-up duration of 1 year (range 0.3–2.0 years). One aneurysm (0.4%) ruptured 10 months after initial discovery. Statistically significant risk factors for growth or rupture were autosomal-dominant polycystic kidney disease (RR 8.3, 95% CI 2.0–34.7), aspect ratio > 1.6 or size ratio > 3 (RR 10.8, 95% CI 2.2–52.2), and initial size ≥ 7 mm (RR 10.7, 95% CI 2.7–42.8).

CONCLUSIONS

Significant growth of unruptured intracranial aneurysms may occur in a small proportion of patients during short-term follow-up. As aneurysm growth is associated with an increased risk of rupture, the authors advocate that short-term follow-up is clinically relevant and has an important role in reducing the risk of a potential SAH.

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James K. Liu and Vincent N. Dodson

Brainstem cavernous malformations are formidable lesions because of their eloquent location and propensity for bleeding resulting in neurological impairment. The surgical management can be challenging due to their deep location around critical neurovascular structures. In this operative video manuscript, the authors demonstrate resection of a large recurrent pontine cavernous malformation with an exophytic component in the cerebellopontine angle via a combined petrosal approach. Both anterior and posterior (retrolabyrinthine) petrosectomies were performed to allow multi-corridor access to the lesion. Due to excessive scar formation from prior surgeries, sharp dissection was paramount to create dissection planes around the lesion. This video atlas demonstrates the operative technique and surgical nuances of the skull base approach, safe resection of the malformation through the operative corridor, gentle handling of the neurovascular structures and a multi-layered reconstruction technique to prevent cerebrospinal fluid leakage. The use of endoscopic-assisted microsurgery of the brainstem is also demonstrated. A gross total resection was achieved, and the patient improved neurologically. In summary, the combined petrosal approach with endoscopic assistance is an important strategy in the armamentarium for the surgical management of brainstem cavernous malformations.

The video can be found here: https://youtu.be/oAETW6tVc_Y.

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Yuichi Murayama, Soichiro Fujimura, Tomoaki Suzuki and Hiroyuki Takao

OBJECTIVE

The authors reviewed the clinical role of computational fluid dynamics (CFD) in assessing the risk of intracranial aneurysm rupture.

METHODS

A literature review was performed to identify reports on CFD assessment of aneurysms using PubMed. The usefulness of various hemodynamic parameters, such as wall shear stress (WSS) and the Oscillatory Shear Index (OSI), and their role in aneurysm rupture risk analysis, were analyzed.

RESULTS

The authors identified a total of 258 published articles evaluating rupture risk, growth, and endovascular device assessment. Of these 258 articles, 113 matching for CFD and hemodynamic parameters that contribute to the risk of rupture (such as WSS and OSI) were identified. However, due to a lack of standardized methodology, controversy remains on each parameter’s role.

CONCLUSIONS

Although controversy continues to exist on which risk factors contribute to predict aneurysm rupture, CFD can provide additional parameters to assess this rupture risk. This technology can contribute to clinical decision-making or evaluation of efficacy for endovascular methods and devices.