Stereotactic radiosurgery for facial nerve schwannomas: A preliminary assessment and review of the literature.

OBJECTIVE: Facial nerve schwannomas (FNS) are rare tumors, and their appropriate management remains the subject of considerable debate. This report details the results of a series of patients with FNS treated with stereotactic radiosurgery (SRS) at the University of Virginia. METHODS: We performed a retrospective review of the clinical and imaging outcomes of 5 patients who underwent Gamma Knife RS (GKRS) for small-to-medium-sized (<5 mL) FNS at our institution. The study population consisted of 3 males and 2 females with a median age of 35 years. All patients presented with varying degrees of facial palsy and/or hearing dysfunction. Tumor volumes at GKRS ranged from 0.1 to 5 (median=0.8) mL. The median maximum radiosurgical dose and tumor margin dose were 24 Gy and 12 Gy, respectively. RESULTS: After a median follow-up period of 12 (range, 6-36) months, three tumors were radiographically smaller and two remained stable. Facial function improved in three patients, remained stable in one patient, and slightly declined from House-Brackmann grade I to II in one patient. Hearing function was preserved in three patients and deteriorated in two patients, one from Gardner-Robertson grade I to II and the other from serviceable hearing grade II to III. CONCLUSION: SRS appears to offer a reasonable rate of facial nerve preservation and tumor control for patients with small-to-medium-sized FNS. Considering the published outcomes achieved with resection, RS may be the preferred first-line treatment for these tumors.

Platypnea Orthodeoxia Due to a Patent Foramen Ovale and Intrapulmonary Shunting After Severe COVID-19 Pneumonia.

BACKGROUND Platypnea orthodeoxia syndrome (POS) presents with positional dyspnea and hypoxemia defined as arterial desaturation of at least 5% or a drop in PaO2 of at least 4 mmHg. Causes of POS include a variety of cardiopulmonary etiologies and has been reported in patients recovering from severe COVID-19 pneumonia. However, clinical presentation and outcomes in a patient with multiple interrelated mechanisms of shunting has not been documented. CASE REPORT An 85-year-old man hospitalized for hypertensive emergency and severe COVID-19 pneumonia was diagnosed with platypnea orthodeoxia on day 28 of illness. During his disease course, the patient required supplemental oxygen by high-flow nasal cannula but never required invasive mechanical ventilation. Chest imaging revealed evolving mixed consolidation and ground-glass opacities with a patchy and diffuse distribution, involving most of the left lung. Echocardiography was ordered to evaluate for intracardiac shunt, which revealed a patent foramen ovale. Closure of the patent foramen ovale was not pursued. Management included graded progression to standing and supplemental oxygen increases when upright. The patient was discharged to a skilled nursing facility and his positional oxygen requirement resolved on approximately day 78. CONCLUSIONS The present case highlights the multiple interrelated mechanisms of shunting in patients with COVID-related lung disease and a patent foramen ovale. Eight prior cases of POS after COVID-19 pneumonia have been reported to date but none with a known patent foramen ovale. In patients with persistent positional oxygen requirements at follow-up, quantifying shunt fraction over time through multiple modalities can guide treatment decisions.

Cerebral Arteriovenous Malformations and Epilepsy, Part 1: Predictors of Seizure Presentation.

OBJECTIVE: Seizures are relatively common in patients harboring cerebral arteriovenous malformations (AVMs). Because the pathogenesis of AVM-associated epilepsy is not well-defined, we aim to determine the factors associated with seizure presentation in AVM patients. METHODS: We evaluated our institutional AVM radiosurgery database, from 1989-2013, to select patients in whom pertinent clinical information at presentation and adequate clinical and radiologic follow-up was available. Baseline patient demographics and AVM angioarchitectural features were compared between patients with and without seizure presentation. In addition to standard descriptive statistics, logistic regression analyses were performed to identify predictors of seizure presentation. RESULTS: Of the 1007 AVM patients included for analysis, 229 patients presented with seizures (22.7%). The incidence of seizure presentation was significantly higher in cortical than noncortical AVMs (33.1% vs. 6.6%, P < 0.0001). Among the cortical locations, occipital AVMs had the lowest rate of seizure presentation (21.5%, P = 0.0012), whereas the rates of seizure presentation in frontal (37.3%), temporal (37.7%), and parietal (34.0%) AVMs were similar. The lack of prior AVM hemorrhage (P < 0.0001), larger nidus diameter (P < 0.0001), and cortical location (P < 0.0001) were independent predictors of seizure presentation in the multivariate analysis. The strongest independent predictors of seizure presentation were lack of prior AVM hemorrhage (OR 16.8) and cortical location (OR 4.2). CONCLUSIONS: Large, unruptured, cortical nidi are most prone to seizure presentation in patients referred for radiosurgery. Further investigations of the molecular biology, neuronal and glial physiology, and natural history of AVM-associated epilepsy appear warranted.

Radiosurgery for temporal lobe arteriovenous malformations: effect of temporal location on seizure outcomes.

OBJECT: The temporal lobe is particularly susceptible to epileptogenesis. However, the routine use of anticonvulsant therapy is not implemented in temporal lobe AVM patients without seizures at presentation. The goals of this case-control study were to determine the radiosurgical outcomes for temporal lobe AVMs and to define the effect of temporal lobe location on postradiosurgery AVM seizure outcomes. METHODS: From a database of approximately 1400 patients, the authors generated a case cohort from patients with temporal lobe AVMs with at least 2 years follow-up or obliteration. A control cohort with similar baseline AVM characteristics was generated, blinded to outcome, from patients with non-temporal, cortical AVMs. They evaluated the rates and predictors of seizure freedom or decreased seizure frequency in patients with seizures or de novo seizures in those without seizures. RESULTS: A total of 175 temporal lobe AVMs were identified based on the inclusion criteria. Seizure was the presenting symptom in 38% of patients. The median AVM volume was 3.3 cm3, and the Spetzler-Martin grade was III or higher in 39% of cases. The median radiosurgical prescription dose was 22 Gy. At a median clinical follow-up of 73 months, the rates of seizure control and de novo seizures were 62% and 2%, respectively. Prior embolization (p = 0.023) and lower radiosurgical dose (p = 0.027) were significant predictors of seizure control. Neither temporal lobe location (p = 0.187) nor obliteration (p = 0.522) affected seizure outcomes. The cumulative obliteration rate was 63%, which was significantly higher in patients without seizures at presentation (p = 0.046). The rates of symptomatic and permanent radiation-induced changes were 3% and 1%, respectively. The annual risk of postradiosurgery hemorrhage was 1.3%. CONCLUSIONS: Radiosurgery is an effective treatment for temporal lobe AVMs. Furthermore, radiosurgery is protective against seizure progression in patients with temporal lobe AVM-associated seizures. Temporal lobe location does not affect radiosurgery-induced seizure control. The low risk of new-onset seizures in patients with temporal or extratemporal AVMs does not seem to warrant prophylactic use of anticonvulsants.

Cerebral Arteriovenous Malformations and Epilepsy, Part 2: Predictors of Seizure Outcomes Following Radiosurgery.

OBJECTIVE: Seizure outcomes after arteriovenous malformation (AVM) management with radiosurgery are incompletely understood. In this case-control study, we aim to determine the incidences and define the predictors of seizure improvement and de novo seizures in patients with AVM with and without seizures at presentation, respectively. METHODS: We evaluated our institutional AVM radiosurgery database to determine the factors that were associated with favorable seizure outcome (seizure improvement or lack of de novo seizures). In patients with seizures at presentation, seizure improvement was defined as decreased seizure frequency or complete seizure remission. In patients without seizures at presentation, de novo seizures were defined as new-onset seizures after radiosurgery. Logistic regression analyses were performed to identify predictors of favorable seizure outcome. RESULTS: In 229 patients with seizures at presentation, the rates of seizure improvement and seizure remission were 57% and 20%, respectively. Prior AVM hemorrhage (P = 0.015), longer follow-up (P < 0.0001), and lack of hemorrhage after radiosurgery (P = 0.048) were independent predictors of seizure improvement in the multivariate analysis. In 778 patients without seizures at presentation, the overall rate of de novo seizures was 1.7%. Prior AVM hemorrhage (P = 0.001) and higher Spetzler-Martin grade (P = 0.018) were independent predictors of the absence of de novo seizures in the multivariate analysis. AVM obliteration was not significantly associated with seizure outcomes after radiosurgery. CONCLUSIONS: Radiosurgery provides reasonable rates of seizure improvement for patients with AVM who present with seizures. For patients with AVM without seizures at presentation, the risk of de novo seizures after radiosurgery is very low, obviating the need for prophylactic antiepileptic drug therapy. Further investigation of epilepsy in patients with AVM undergoing stereotactic radiosurgery should be considered with validated outcome measures and prospective study design.