Publications by authors named "Karras C"

Background And Objective: While safe and effective modalities exist to treat small arteriovenous malformations (AVMs), large (>10 cm) AVMs remain difficult to cure via surgical or endovascular means. Staged stereotactic radiosurgery (SRS), either volume-staged (VS) or dose-staged (DS), has been proposed for large AVMs. The relative efficacy of these two strategies, with or without endovascular embolization, is unclear.

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Objective: To preserve facial nerve function in vestibular schwannoma (VS) microsurgery, some have advocated subtotal resection (STR) if the tumor is densely adherent to a thinned facial nerve. The objective of this study was to determine if residual volume is associated with progression and whether there is a threshold residual volume that should be pursued during STR to prevent recurrence. A secondary objective of this study was to determine whether facial nerve function at last follow-up was associated with extent of resection (EOR).

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Objective: Cervical spinal cord injury (SCI) and lower trunk brachial plexus injury (BPI) commonly result in hand paralysis. Although restoring hand function is complex and challenging to achieve, regaining volitional hand control drastically enhances functionality for these patients. The authors aimed to systematically review the outcomes of hand-opening function after supinator to posterior interosseous nerve (PIN) transfer.

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Article Synopsis
  • The study investigates the clinical characteristics and outcomes of trigeminal schwannoma (TS) surgical resections across two institutions from 2004 to 2022, analyzing data from 30 patients.
  • Most patients were middle-aged, with common symptoms including sensory loss and headaches; tumors primarily consisted of mixed cystic-solid types with an average diameter of 3.3 cm.
  • Although 87% of patients reported symptom improvements after surgery, there were notable risks, with 17% experiencing temporary and 10% experiencing permanent cranial nerve deficits.
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The point spread function (PSF) of a microscope describes the image of a point emitter. Knowing the accurate PSF model is essential for various imaging tasks, including single-molecule localization, aberration correction and deconvolution. Here we present universal inverse modeling of point spread functions (uiPSF), a toolbox to infer accurate PSF models from microscopy data, using either image stacks of fluorescent beads or directly images of blinking fluorophores, the raw data in single-molecule localization microscopy (SMLM).

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Objectives: Increased fetal lung heterogeneity has been associated with term fetal lungs in singleton gestations. The objective of this study was to determine if fetal lung heterogeneity index (HI) differs between twin and singleton fetuses in the late second and third trimesters.

Methods: Prospective cohort study of women with singleton and twin gestations with medically-indicated ultrasound examinations at 24 weeks of gestation onward.

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Article Synopsis
  • Meningioma classification and treatment have advanced significantly since their early descriptions in the 1920s, focusing on improving prognostication through histopathology, radiography, and molecular profiling.
  • Accurate classification is vital for patient management, involving monitoring, surgery, radiotherapy, and potential clinical trials, primarily guided by WHO grade, extent of resection, and patient features.
  • Recent research has identified molecular markers related to the disease's aggressiveness and response to treatment, though challenges remain in applying these discoveries effectively in clinical settings.
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Objective: Parasagittal meningiomas (PM) are treated with primary microsurgery, radiosurgery (SRS), or surgery with adjuvant radiation. We investigated predictors of tumor progression requiring salvage surgery or radiation treatment. We sought to determine whether primary treatment modality, or radiologic, histologic, and clinical variables were associated with tumor progression requiring salvage treatment.

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To characterize neurocognitive response to cerebrospinal fluid (CSF) diversion during a multiday external lumbar drainage (ELD) trial in patients with suspected normal pressure hydrocephalus (NPH). Inpatients ( = 70) undergoing an ELD trial as part of NPH evaluation participated. Cognition and balance were assessed using standardized measures before and after a three-day ELD trial.

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In the evolving landscape of Industry 4.0, the convergence of peer-to-peer (P2P) systems, LoRa-enabled wireless sensor networks (WSNs), and distributed hash tables (DHTs) represents a major advancement that enhances sustainability in the modern agriculture framework and its applications. In this study, we propose a P2P Chord-based ecosystem for sustainable and smart agriculture applications, inspired by the inner workings of the Chord protocol.

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The point spread function (PSF) of a microscope describes the image of a point emitter. Knowing the accurate PSF model is essential for various imaging tasks, including single molecule localization, aberration correction and deconvolution. Here we present uiPSF (universal inverse modelling of Point Spread Functions), a toolbox to infer accurate PSF models from microscopy data, using either image stacks of fluorescent beads or directly images of blinking fluorophores, the raw data in single molecule localization microscopy (SMLM).

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 Vestibular schwannomas (VSs) are treated with microsurgery and/or radiosurgery. Repeat resection is rare, and few studies have reported postoperative outcomes. The objective of this study was to describe clinical characteristics and outcomes in patients undergoing repeat surgery for VS.

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Article Synopsis
  • Trigeminal schwannomas (TS) are usually non-cancerous tumors, but they can sometimes be large or cause problems, leading to the need for surgery.
  • A study collected data from 26 research papers about 974 patients who had surgery for TS, focusing on their experiences and outcomes.
  • The study found that patients who had a complete removal of the tumor (gross total resection) had a much lower chance of the tumor coming back compared to those who didn’t get it all removed.
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  • This systematic review and individual patient data analysis aimed to summarize existing research on pineoblastoma, a rare type of brain tumor, and evaluate factors affecting overall survival.
  • The study analyzed data from 44 studies and 298 patients, using methods like Kaplan-Meier analyses and Cox regression to identify significant predictors of mortality.
  • Findings indicated that poorer prognostic factors included incomplete tumor resection, metastatic disease, and young age at diagnosis, but overall survival rates have improved significantly from 2012, rising from 32.8% to 56.1%.
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Background: The VS-5 index was recently proposed to predict complications, nonroutine discharge, length of stay (LOS), and cost after vestibular schwannoma (VS) resection. The VS-5 ranges from 0-17.86, and a score ≥2 was proposed as being predictive of postoperative adverse events.

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Objective: Odontoid fractures can be managed surgically when indicated. The most common approaches are anterior dens screw (ADS) fixation and posterior C1-C2 arthrodesis (PA). Each approach has theoretical advantages, but the optimal surgical approach remains controversial.

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Background: Spetzler-Martin (SM) grade III arteriovenous malformations (AVMs) show angioarchitecture heterogeneity and lack a clearly defined treatment strategy. This study aims to evaluate outcomes after treatment of SM grade III AVMs with Gamma Knife radiosurgery (GKRS).

Methods: A single-institution retrospective analysis was conducted of 307 patients with SM grade III AVMs undergoing GKRS between October 2006 and December 2020 with follow-up times of at least 24 months.

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Objective: The coronavirus disease 2019 (COVID-19) pandemic has necessitated the use of telehealth visits (THVs). The effects on neurosurgical practice have not been well characterized, especially concerning new-patient THVs. Therefore, the authors of this study reviewed their institution's experience with outpatient clinic visits and THVs from before the COVID-19 pandemic to the present to focus on clinical metrics, rates of surgery, and the effects of implementing THVs in order to better understand their implications for clinical practice as more data emerge over time.

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Background: Stereotactic body radiotherapy (SBRT) has been established as a safe and effective treatment modality for control of long-term pain and tumor growth. However, few studies have investigated the efficacy of postoperative SBRT versus conventional external beam radiation therapy (EBRT) in extending survival within the context of systemic therapy.

Methods: A retrospective chart review of patients who underwent surgery for spinal metastasis at our institution was conducted.

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Objective: Sociodemographic factors may play a role in incidence and treatment of metastatic spinal tumors, as there is a delay in diagnosis and increased incidence of relevant primaries. There has yet to be a detailed analysis of the impact of sociodemographic factors on surgical outcomes for spinal metastases. We sought to examine the influence of socioeconomic factors on outcomes for patients with metastatic spinal tumors.

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Supratentorial non-skull base meningiomas are the most common primary central nervous system tumor subtype. An understanding of their pathophysiology, imaging characteristics, and clinical management options will prove of substantial value to the multi-disciplinary team which may be involved in their care. Extensive review of the broad literature on the topic is conducted.

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Objective: Foramen magnum meningiomas (FMMs) pose a unique challenge given their intimate anatomical relationship with the craniovertebral junction. While resection has been studied extensively, much less has been reported about the use of stereotactic radiosurgery (SRS) for FMMs. This study includes what is to the authors' knowledge the first systematic review in the literature that summarizes patient and treatment characteristics and synthesizes outcomes following SRS for FMMs.

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Objective: To explore the difference in post-operative DVT, PE, and ICH complications following administration of prophylactic UFH or enoxaparin in patients undergoing craniotomy.

Methods: A retrospective chart review was conducted for 542 patients at our institution receiving either 5000units/0.5 mL UFH (BID or TID; 180 patients) or single daily 40 mg/0.

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Article Synopsis
  • The study analyzed the safety and effectiveness of the endoscopic endonasal approach (EEA) for pediatric skull base surgery over an 11-year period, involving 94 patients and 130 surgeries.
  • It found that common presenting symptoms included endocrinopathies, vision abnormalities, and cranial nerve deficits, with EEA being employed in the majority of surgeries to treat conditions like craniopharyngioma and pituitary adenoma.
  • Results indicated that EEA is safe with complication rates comparable to adult patients, showing it as a viable option for managing various diseases of the anterior cranial base in children.
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