VTechWorks staff will be away for the Thanksgiving holiday beginning at noon on Wednesday, November 27, through Friday, November 29. We will resume normal operations on Monday, December 2. Thank you for your patience.

Browsing by Author "In, Alexander"

Now showing 1 - 3 of 3
  • Thumbnail Image
    Co-occurrence of dural arteriovenous fistula and meningioma: A rare case and systematic review
    Bhutada, Abhishek S.; Adhikari, Srijan; Cuoco, Joshua A.; In, Alexander; Entwistle, John J.; Witcher, Mark R. (Elsevier, 2023-07-01)
    Background: The coexistence of meningioma and dural arteriovenous fistula (dAVF) is a rare, but highly complex condition. Various pathophysiological mechanisms underlie intracranial meningiomas with continuous or distant dAVFs. We describe a case of coexisting meningioma and dAVF with a systematic review of the literature. Result: Including the present case, there are 21 reported cases of coexisting intracranial dAVF and meningioma. The patients’ ages ranged from 23 to 76 years, with a mean age of 61 years. The most common presenting symptom was headache. The dAVFs were commonly located at the transverse-sigmoid sinus (43%) and superior sagittal sinus (24%). The most common meningioma locations were the tentorium and parietal convexity. In 76% of the cases, the meningioma occluded the sinus. The most common dAVF treatment was transcatheter arterial embolization, followed by tumor resection (52%). Among the 20 cases with available outcome data, 90% reported favorable outcomes. Conclusion: This report highlights some of the features of coexisting dAVF and meningioma and presents a systematic review of other reports on this phenomenon. Through an in-depth analysis of the literature, we highlight some of the leading theories regarding the causes of concomitant dAVF and meningiomas. Our report supports one of the leading theories that impaired venous return, whether through the occlusion of sinuses or sinus manipulation during surgery, plays a role in the development of dAVF. Further understanding may help guide future clinical decision-making and surgical planning.
  • Thumbnail Image
    Noninvasive neuromodulation of subregions of the human insula differentially affect pain processing and heart-rate variability: a within-subjects pseudo-randomized trial
    Legon, Wynn; Strohman, Andrew; In, Alexander; Payne, Brighton (Wolters Kluwer Health, Inc., 2024-02-01)
    The insula is an intriguing target for pain modulation. Unfortunately, it lies deep to the cortex making spatially specific noninvasive access difficult. Here, we leverage the high spatial resolution and deep penetration depth of low-intensity focused ultrasound (LIFU) to nonsurgically modulate the anterior insula (AI) or posterior insula (PI) in humans for effect on subjective pain ratings, electroencephalographic (EEG) contact heat–evoked potentials, as well as autonomic measures including heart-rate variability (HRV). In a within-subjects, repeated-measures, pseudo-randomized trial design, 23 healthy volunteers received brief noxious heat pain stimuli to the dorsum of their right hand during continuous heart-rate, electrodermal, electrocardiography and EEG recording. Low-intensity focused ultrasound was delivered to the AI (anterior short gyrus), PI (posterior longus gyrus), or under an inert Sham condition. The primary outcome measure was pain rating. Low-intensity focused ultrasound to both AI and PI similarly reduced pain ratings but had differential effects on EEG activity. Low-intensity focused ultrasound to PI affected earlier EEG amplitudes, whereas LIFU to AI affected later EEG amplitudes. Only LIFU to the AI affected HRV as indexed by an increase in SD of N-N intervals and mean HRV low-frequency power. Taken together, LIFU is an effective noninvasive method to individually target subregions of the insula in humans for site-specific effects on brain biomarkers of pain processing and autonomic reactivity that translates to reduced perceived pain to a transient heat stimulus.
  • Thumbnail Image
    Prognostic Factors and Nomogram for Choroid Plexus Tumors: A Population-Based Retrospective Surveillance, Epidemiology, and End Results Database Analysis
    Bhutada, Abhishek S.; Adhikari, Srijan; Cuoco, Joshua A.; In, Alexander; Rogers, Cara M.; Jane, John A.; Marvin, Eric A. (MDPI, 2024-01-31)
    Background: Choroid plexus tumors (CPTs) are rare neoplasms found in the central nervous system, comprising 1% of all brain tumors. These tumors include choroid plexus papilloma (CPP), atypical choroid plexus papilloma (aCPP), and choroid plexus carcinoma (CPC). Although gross total resection for choroid plexus papillomas (CPPs) is associated with long-term survival, there is a scarcity of prospective data concerning the role and sequence of neoadjuvant therapy in treating aCPP and CPC. Methods: From the years 2000 to 2019, 679 patients with CPT were identified from the Surveillance, Epidemiology, and End Result (SEER) database. Among these patients, 456 patients had CPP, 75 patients had aCPP, and 142 patients had CPC. Univariate and multivariable Cox proportional hazard models were run to identify variables that had a significant impact on the primary endpoint of overall survival (OS). A predictive nomogram was built for patients with CPC to predict 5-year and 10-year survival probability. Results: Histology was a significant predictor of OS, with 5-year OS rates of 90, 79, and 61% for CPP, aCPP, and CPC, respectively. Older age and African American race were prognostic for worse OS for patients with CPP. Older age was also associated with reduced OS for patients with aCPP. American Indian/Alaskan Native race was linked to poorer OS for patients with CPC. Overall, treatment with gross total resection or subtotal resection had no difference in OS in patients with CPP or aCPP. Meanwhile, in patients with CPC, gross total resection (GTR) was associated with significantly better OS than subtotal resection (STR) only. However, there is no difference in OS between patients that receive GTR and patients that receive STR with adjuvant therapy. The nomogram for CPC considers types of treatments received. It demonstrates acceptable accuracy in estimating survival probability at 5-year and 10-year intervals, with a C-index of 0.608 (95% CI of 0.446 to 0.77). Conclusions: This is the largest study on CPT to date and highlights the optimal treatment strategies for these rare tumors. Overall, there is no difference in OS with GTR vs. STR in CPP or aCPP. Furthermore, OS is equivalent for CPC with GTR and STR plus adjuvant therapy.