The risk of intraoperative venous air embolism from neurosurgical procedures performed in the lounging position

J Neurosurg 142:797–807, 2025

The study investigated the risk of venous air embolism (VAE) during neurosurgery in the lounging position, finding no permanent sequelae or fatal events. Despite a 51.4% VAE detection rate, no hemodynamic instability occurred, suggesting experienced teams can safely use this position.

Study Overview

Objective: Assess venous air embolism (VAE) risk and outcomes in lounging position neurosurgery.

Study Design: Retrospective analysis of 1000 patients from 2010 to 2020.

Primary Focus: VAE incidence, severity, and associated complications.

Key Findings

VAE Detection: 51.4% of patients experienced VAE, with no grade 5 events.

Complications: 0.3% developed acute respiratory distress syndrome (ARDS) linked to VAE grade.

No Permanent Sequelae: No patients suffered permanent neurological deficits from VAE.

Patient Demographics

Mean Age: 47.7 years; 56.5% female.

Common Pathologies: 94.9% had posterior fossa tumors, mainly vestibular schwannomas.

Surgical Approach and Positioning

Lounging Position: Feet elevated above head to improve venous return.

Surgical Benefits: Reduced intracranial pressure and improved surgical field visibility.

Risk Factors and Outcomes

High-Grade VAE: Associated with older age and lower BMI.

No PFO Contraindication: PFO is not linked to paradoxical embolism in this cohort.

Outcome Predictors: Preoperative KPS score is most relevant for clinical outcomes.

Adult Posterior Fossa Anaplastic Ependymoma

World Neurosurg. (2022) 158:205-209

Ependymomas are rare central nervous system tumors. The current treatment strategy is gross total tumor removal. Whether adjuvant therapy will be beneficial is controversial. We retrospectively analyzed 3 cases of World Health Organization (WHO) grade III posterior fossa anaplastic ependymomas treated with different treatment modalities. We aimed to identify possible treatment options for infratentorial WHO grade III anaplastic ependymoma in adults.

METHODS: We performed a retrospective analysis of 3 patients diagnosed with infratentorial anaplastic ependymomas in our institution from 2016 to 2020. The demographic data were documented. This case series of 3 patients does not meet the Department of Health and Human Services definition of research and does not need Institutional Review Board approval. All patients’ informed consents have been obtained.

RESULTS: One patient underwent subtotal tumor resection combined with adjuvant radiotherapy and Gamma Knife radiosurgery while the other 2 patients underwent gross total tumor removal combined with Gamma Knife radiosurgery or adjuvant radiotherapy. Tumors recurred in the first patient 20 months later, while the other 2 patents did not develop recurrence. The modified Rankin scale scores of these patients were 1, 0, and 0. All patients are followed up with regular magnetic resonance imaging at our facility.

CONCLUSIONS: The strategy for treating WHO grade III anaplastic ependymomas is controversial, but gross total tumor resection remains the key element. Adjuvant stereotactic radiosurgery after tumor removal might be considered if radiotherapy is not an option. The role of chemotherapy is unclear, and the use of chemotherapy should be tailored to individual patients

Permanent Cerebrospinal Fluid Diversion in Adults With Posterior Fossa Tumors: Incidence and Predictors

 

Neurosurgery 89:987–996, 2021

Posterior fossa tumors (PFTs) can cause hydrocephalus. Hydrocephalus can persist despite resection of PFTs in a subset of patients requiring permanent cerebrospinal fluid (CSF) diversion. Characteristics of this patient subset are not well defined.

OBJECTIVE: To define preoperative and postoperative variables that predict the need for postoperative CSF diversion in adult patients with PFTs.

METHODS: We surveyed the CNS (Central Nervous System) Tumor Outcomes Registry at Emory (CTORE) for patients who underwent PFT resection at 3 tertiary-care centers between 2006 and 2019. Demographic, radiographic, perioperative, and dispositional data were analyzed using univariate and multivariate models.

RESULTS:We included 617 patients undergoing PFT resection for intra-axial (57%) or extraaxial (43%) lesions. Gross total resection was achieved in 62% of resections. Approximately 13% of patients required permanent CSF diversion/shunting. Only 31.5% of patients who required pre- or intraop external ventricular drain (EVD) placement needed permanent CSF diversion. On logistic regression, size, transependymal flow, use of perioperative EVD, postoperative intraventricular hemorrhage (IVH), and surgical complications were predictors of permanent CSF diversion. Preoperative tumor size was only independent predictor of postoperative shunting in patients with subtotal resection. In patients with intra-axial tumors, transependymal flow (P = .014), postoperative IVH (P = .001), surgical complications (P = .013), and extent of resection (P = .03) predicted need for shunting. In extra-axial tumors, surgical complications were the major predictor (P = .022).

CONCLUSION: Our study demonstrates that presence of preoperative hydrocephalus in patients with PFT does not necessarily entail the need for permanent CSF diversion. We report the major predictive factors for needing permanent CSF diversion.