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Antero-lateral transthoracic endoscopic approach for a calcified thoracic disc herniation

Roque Carlos Fernández, Miguel Mesa, Daniel Rosenthal, and Victor Rodrigo Paradells

Thoracic disc herniation is one of the most therapeutically challenging spine conditions. A myriad of surgical approaches have been described in the literature, including posterior, anterior, and combined techniques. However, transthoracic and retropleural approaches are currently deemed the most effective techniques to successfully obtain anterior decompression. Herein the authors describe a 65-year-old female patient who underwent a transthoracic endoscopic approach to remove a calcified herniated thoracic disc that caused spinal cord compression. Despite having a long learning curve, the surgical technique described herein can be even used in patients with complex and calcified thoracic disc herniations.

The video can be found here: https://stream.cadmore.media/r10.3171/2022.3.FOCVID221

In Neurosurgical Focus: Video Volume 7: Issue 1 (Jul 2022): Lateral Access Spine Surgery

Free access

Arteriovenous malformations of the filum terminale: clinical characteristics, angioarchitecture, and management of a rare spinal vascular pathology

Michael Mull, Manuel Dafotakis, Gerrit Alexander Schubert, Franz-Josef Hans, and Fidaa Jablawi

OBJECTIVE

The goal of this study was to describe clinical and neuroradiological features of arteriovenous malformations of the filum terminale (FT AVMs) and to present the authors’ diagnostic and therapeutic management in this rare disease.

METHODS

The presented cases were retrieved from a retrospectively collected database of all spinal vascular malformations treated between June 1992 and December 2021 at the Rheinisch-Westfälische Technische Hochschule (RWTH) University Hospital Aachen. Pretreatment and follow-up clinical and neuroradiological data were analyzed for this study.

RESULTS

Data in 15 patients with FT AVM with a mean age of 60 years were included, with an overall incidence of FT AVM of 19% among all spinal AVMs in our cohort. Twelve of 15 (80%) patients were men. Nonspecific but typical clinical and MR findings of thoracolumbar congestive myelopathy were found in all patients. Spinal MR angiography, performed in 10 patients, identified in all cases the arterialized FT vein as well as a lumbar/lumbosacral location of an AV shunt. Digital subtraction angiography (DSA) showed an arterial supply solely via the FT artery in 12/15 (80%) patients and via an additional feeder from the lumbosacral region in the other 3/15 (20%) patients. All patients were treated surgically. During 1-year follow-up, 2 patients presented with recurrent FT AVM due to further arterial supply from the lumbosacral region, and were treated surgically. Neurological status was improved in all patients within the 1-year follow-up, with marginal further changes during long-term follow-up.

CONCLUSIONS

Congestive myelopathy is the major pathological mechanism of symptoms in these patients, with no evidence for intradural bleeding. Missing the presence of possible multiple arterial supply of FT AVM during DSA may result in misdiagnosis and/or insufficient treatment. Due to the frequently prolonged course of FT artery, resection of the FT AVM may be a favorable treatment modality in comparison with endovascular treatment. Follow-up examinations are obligatory within the first 3 years after treatment, and further MR angiography and DSA examinations are indicated if congestive myelopathy persists.

In Neurosurgical Focus Volume 53 (2022): Issue 1 (Jul 2022): Arteriovenous Malformations

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Breaking boundaries through Doctors Reaching Minority Men Exploring Neuroscience: a mentorship model to foster a pipeline for underrepresented minorities

Ian T. McNeill, Alejandro Carrasquilla, Zerubabbel K. Asfaw, Ernest J. Barthélemy, Alyson Mehr, Kenya D. Townsend, Alexander Joseph, Joshua B. Bederson, Gary C. Butts, and Isabelle M. Germano

OBJECTIVE

In 2015, the Association of American Medical Colleges report titled "Altering the Course: Black Males in Medicine" showed a decline in the number of Black men matriculating into medical school. To alter this trend, the authors’ hypothesis was that formally exposing Black men to the clinical neurosciences during high school would enhance their chances of entering the physician workforce. For this reason, in 2007, the Doctors Reaching Minority Men Exploring Neuroscience (DR. MMEN) program was established at the Icahn School of Medicine at Mount Sinai. The program aimed to provide early exposure, mentorship, and inspiration to high school–age Black and Latinx men. The aim of this study was to evaluate the impact of the DR. MMEN program in the context of the recent race and ethnicity trends among medical school matriculants (MSMs).

METHODS

Association of American Medical Colleges data on MSMs stratified by race and ethnicity were reviewed for the period between 2015 and 2020. Data pertinent to the academic achievements of DR. MMEN participants, such as matriculation to college and/or medical school, were prospectively tracked and incorporated with mixed-methods exit assessment data. Qualitative responses were coded and analyzed using a thematic concept analysis method.

RESULTS

Over the study period, the increase of MSMs in the US was 1.0% and 1.7% for Black and Latinx individuals, respectively. Changes for the male MSM cohort were negligible: 0.3% for Black and 0.7% for Latinx. With respect to DR. MMEN, 42% of participants from 2017 to 2019 earned college scholarships, and 25% of students from the 2017–2018 cohort matriculated to a combined college–medical program. Survey data showed that 100% of DR. MMEN participants found the program useful. Analysis of qualitative data revealed that participants considered pursuing a career in neurosurgery or in another medical field. Diligence and a passion for medicine were identified as the top two most important lessons in the program, and witnessing patient satisfaction and observing a neurosurgery operation were described as the most important experiences. Participants considered availability to give advice and feedback and a passion for teaching as the principal attributes of their mentors.

CONCLUSIONS

Over the past 6 years, the slight increase in Black and Latinx MSMs has not been significant enough to remedy ethnoracial disparities among MSMs. In particular, Black male matriculation to medical school has remained stagnant. The DR. MMEN program is a promising model to inspire young scholars and improve diversity within neuroscience and medicine at large.

In Journal of Neurosurgery Publish Before Print

Free access

Cerebral vasospasm following arteriovenous malformation rupture: a population-based cross-sectional study

Alis J. Dicpinigaitis, Eric Feldstein, Steven D. Shapiro, Haris Kamal, Andrew Bauerschmidt, Jon Rosenberg, Krishna Amuluru, Jared Pisapia, Neha S. Dangayach, John W. Liang, Christian A. Bowers, Stephan A. Mayer, Chirag D. Gandhi, and Fawaz Al-Mufti

OBJECTIVE

Studies examining the risk factors and clinical outcomes of arterial vasospasm secondary to cerebral arteriovenous malformation (cAVM) rupture are scarce in the literature. The authors used a population-based national registry to investigate this largely unexamined clinical entity.

METHODS

Admissions for adult patients with cAVM ruptures were identified in the National Inpatient Sample during the period from 2015 to 2019. Complex samples multivariable logistic regression and chi-square automatic interaction detection (CHAID) decision tree analyses were performed to identify significant associations between clinical covariates and the development of vasospasm, and a cAVM–vasospasm predictive model (cAVM-VPM) was generated based on the effect sizes of these parameters.

RESULTS

Among 7215 cAVM patients identified, 935 developed vasospasm, corresponding to an incidence rate of 13.0%; 110 of these patients (11.8%) subsequently progressed to delayed cerebral ischemia (DCI). Multivariable adjusted modeling identified the following baseline clinical covariates: decreasing age by decade (adjusted odds ratio [aOR] 0.87, 95% CI 0.83–0.92; p < 0.001), female sex (aOR 1.68, 95% CI 1.45–1.95; p < 0.001), admission Glasgow Coma Scale score < 9 (aOR 1.34, 95% CI 1.01–1.79; p = 0.045), intraventricular hemorrhage (aOR 1.87, 95% CI 1.17–2.98; p = 0.009), hypertension (aOR 1.77, 95% CI 1.50–2.08; p < 0.001), obesity (aOR 0.68, 95% CI 0.55–0.84; p < 0.001), congestive heart failure (aOR 1.34, 95% CI 1.01–1.78; p = 0.043), tobacco smoking (aOR 1.48, 95% CI 1.23–1.78; p < 0.019), and hospitalization events (leukocytosis [aOR 1.64, 95% CI 1.32–2.04; p < 0.001], hyponatremia [aOR 1.66, 95% CI 1.39–1.98; p < 0.001], and acute hypotension [aOR 1.67, 95% CI 1.31–2.11; p < 0.001]) independently associated with the development of vasospasm. Intraparenchymal and subarachnoid hemorrhage were not associated with the development of vasospasm following multivariable adjustment. Among significant associations, a CHAID decision tree algorithm identified age 50–59 years (parent node), hyponatremia, and leukocytosis as important determinants of vasospasm development. The cAVM-VPM achieved an area under the curve of 0.65 (sensitivity 0.70, specificity 0.53). Progression to DCI, but not vasospasm alone, was independently associated with in-hospital mortality (aOR 2.35, 95% CI 1.29–4.31; p = 0.016) and lower likelihood of routine discharge (aOR 0.62, 95% CI 0.41–0.96; p = 0.031).

CONCLUSIONS

This large-scale assessment of vasospasm in cAVM identifies common clinical risk factors and establishes progression to DCI as a predictor of poor neurological outcomes.

In Neurosurgical Focus Volume 53 (2022): Issue 1 (Jul 2022): Arteriovenous Malformations

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Comparison of the impact of skull density ratio with alternative skull metrics on magnetic resonance–guided focused ultrasound thalamotomy for tremor

Jason Yuen, Abhinav Goyal, Timothy J. Kaufmann, Lauren M. Jackson, Kai J. Miller, Bryan T. Klassen, Neha Dhawan, Kendall H. Lee, and Vance T. Lehman

OBJECTIVE

One of the key metrics that is used to predict the likelihood of success of MR-guided focused ultrasound (MRgFUS) thalamotomy is the overall calvarial skull density ratio (SDR). However, this measure does not fully predict the sonication parameters that would be required or the technical success rates. The authors aimed to assess other skull characteristics that may also contribute to technical success.

METHODS

The authors retrospectively studied consecutive patients with essential tremor who were treated by MRgFUS at their center between 2017 and 2021. They evaluated the correlation between the different treatment parameters, particularly maximum power and energy delivered, with a range of patients’ skull metrics and demographics. Machine learning algorithms were applied to investigate whether sonication parameters could be predicted from skull density metrics alone and whether including combined local transducer SDRs with overall calvarial SDR would increase model accuracy.

RESULTS

A total of 62 patients were included in the study. The mean age was 77.1 (SD 9.2) years, and 78% of treatments (49/63) were performed in males. The mean SDR was 0.51 (SD 0.10). Among the evaluated metrics, SDR had the highest correlation with the maximum power used in treatment (ρ = −0.626, p < 0.001; proportion of local SDR values ≤ 0.8 group also had ρ = +0.626, p < 0.001) and maximum energy delivered (ρ = −0.680, p < 0.001). Machine learning algorithms achieved a moderate ability to predict maximum power and energy required from the local and overall SDRs (accuracy of approximately 80% for maximum power and approximately 55% for maximum energy), and high ability to predict average maximum temperature reached from the local and overall SDRs (approximately 95% accuracy).

CONCLUSIONS

The authors compared a number of skull metrics against SDR and showed that SDR was one of the best indicators of treatment parameters when used alone. In addition, a number of other machine learning algorithms are proposed that may be explored to improve its accuracy when additional data are obtained. Additional metrics related to eventual sonication parameters should also be identified and explored.

In Journal of Neurosurgery Publish Before Print

Free access

De novo epilepsy after microsurgical resection of brain arteriovenous malformations

Rajeev D. Sen, Dominic Nistal, Margaret McGrath, Guilherme Barros, Varadaraya Satyanarayan Shenoy, Laligam N. Sekhar, Michael R. Levitt, and Louis J. Kim

OBJECTIVE

Seizures are the second most common presenting symptom of brain arteriovenous malformations (bAVMs) after hemorrhage. Risk factors for preoperative seizures and subsequent seizure control outcomes have been well studied. There is a paucity of literature on postoperative, de novo seizures in initially seizure-naïve patients who undergo resection. Whereas this entity has been documented after craniotomy for a wide variety of neurosurgically treated pathologies including tumors, trauma, and aneurysms, de novo seizures after bAVM resection are poorly studied. Given the debilitating nature of epilepsy, the purpose of this study was to elucidate the incidence and risk factors associated with de novo epilepsy after bAVM resection.

METHODS

A retrospective review of patients who underwent resection of a bAVM over a 15-year period was performed. Patients who did not present with seizure were included, and the primary outcome was de novo epilepsy (i.e., a seizure disorder that only manifested after surgery). Demographic, clinical, and radiographic characteristics were compared between patients with and without postoperative epilepsy. Subgroup analysis was conducted on the ruptured bAVMs.

RESULTS

From a cohort of 198 patients who underwent resection of a bAVM during the study period, 111 supratentorial ruptured and unruptured bAVMs that did not present with seizure were included. Twenty-one patients (19%) developed de novo epilepsy. One-year cumulative rates of developing de novo epilepsy were 9% for the overall cohort and 8.5% for the cohort with ruptured bAVMs. There were no significant differences between the epilepsy and no-epilepsy groups overall; however, the de novo epilepsy group was younger in the cohort with ruptured bAVMs (28.7 ± 11.7 vs 35.1 ± 19.9 years; p = 0.04). The mean time between resection and first seizure was 26.0 ± 40.4 months, with the longest time being 14 years. Subgroup analysis of the ruptured and endovascular embolization cohorts did not reveal any significant differences. Of the patients who developed poorly controlled epilepsy (defined as Engel class III–IV), all had a history of hemorrhage and half had bAVMs located in the temporal lobe.

CONCLUSIONS

De novo epilepsy after bAVM resection occurs at an annual cumulative risk of 9%, with potentially long-term onset. Younger age may be a risk factor in patients who present with rupture. The development of poorly controlled epilepsy may be associated with temporal lobe location and a delay between hemorrhage and resection.

In Neurosurgical Focus Volume 53 (2022): Issue 1 (Jul 2022): Arteriovenous Malformations

Free access

Editorial. Curative embolization for low-grade AVMs: ready for prime time?

Giuseppe Lanzino and Lorenzo Rinaldo

In Neurosurgical Focus Volume 53 (2022): Issue 1 (Jul 2022): Arteriovenous Malformations

Free access

Editorial. Management of high-grade brain arteriovenous malformations: the current state of knowledge

James Feghali and Judy Huang

In Neurosurgical Focus Volume 53 (2022): Issue 1 (Jul 2022): Arteriovenous Malformations

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Editorial. Microsurgical treatment of sacral Tarlov cysts

Ken Porche and Daniel J. Hoh

In Journal of Neurosurgery: Spine Publish Before Print

Free access

Emerging pathogenic mechanisms in human brain arteriovenous malformations: a contemporary review in the multiomics era

Ethan A. Winkler, Mark A. Pacult, Joshua S. Catapano, Lea Scherschinski, Visish M. Srinivasan, Christopher S. Graffeo, S. Paul Oh, and Michael T. Lawton

A variety of pathogenic mechanisms have been described in the formation, maturation, and rupture of brain arteriovenous malformations (bAVMs). While the understanding of bAVMs has largely been formulated based on animal models of rare hereditary diseases in which AVMs form, a new era of “omics” has permitted large-scale examinations of contributory genetic variations in human sporadic bAVMs. New findings regarding the pathogenesis of bAVMs implicate changes to endothelial and mural cells that result in increased angiogenesis, proinflammatory recruitment, and breakdown of vascular barrier properties that may result in hemorrhage; a greater diversity of cell populations that compose the bAVM microenvironment may also be implicated and complicate traditional models. Genomic sequencing of human bAVMs has uncovered inherited, de novo, and somatic activating mutations, such as KRAS, which contribute to the pathogenesis of bAVMs. New droplet-based, single-cell sequencing technologies have generated atlases of cell-specific molecular derangements. Herein, the authors review emerging genomic and transcriptomic findings underlying pathologic cell transformations in bAVMs derived from human tissues. The application of multiple sequencing modalities to bAVM tissues is a natural next step for researchers, although the potential therapeutic benefits or clinical applications remain unknown.

In Neurosurgical Focus Volume 53 (2022): Issue 1 (Jul 2022): Arteriovenous Malformations