Publications by authors named "Alvin Y Chan"

Introduction: Spondylodiscitis (SD) is an infection of the intervertebral disc with involvement of the adjacent vertebral bodies. Diagnostic tests with CT-guided biopsy only provide a positive yield in 14%-48% of cases. Percutaneous endoscopic debridement and drainage (PEDD) has recently shown promise in the treatment of spondylodiscitis.

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Background: Unlike syringomyelia, syringobulbia is not commonly observed in pediatric patients with Chiari malformation type I (CMI). Previous series have reported the incidence of syringobulbia as between 3% and 4% in these patients. Presentation is typically chronic, with the slow onset of neurological symptoms and cranial nerve (CN) palsies resulting from lower brainstem involvement.

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Proximal junctional kyphosis (PJK) is a common complication following long-segment thoracolumbar fusions for patients with adult spinal deformities. PJK is described as a progressive kyphosis at the upper instrumented vertebra or 1 or 2 segments adjacent to the instrumented vertebra. This condition can lead to proximal junction failure, which results in vertebral body fractures, screw pullouts, and neurological deficits.

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The leading cause of ventricular shunt failure in pediatric patients is proximal catheter occlusion. Here, we evaluate various types of shunt catheters to assess in vitro cellular adhesion and obstruction. The following four types of catheters were tested: (1) antibiotic- and barium-impregnated, (2) polyvinylpyrrolidone, (3) barium stripe, and (4) barium impregnated.

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Objective: One of the major causes of cerebral ventricular shunt failure is proximal catheter occlusion. We describe a novel ventricular cerebrospinal fluid (CSF) flow replicating system that assesses pressure and flow responses to varying degrees of catheter occlusion.

Methods: Ventricular catheter performance was assessed during conditions of partial and complete occlusion.

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Background: Spindle cell oncocytoma (SCO) of the pituitary gland is an extremely rare nonfunctional World Health Organization grade I tumor. SCOs are often misdiagnosed as nonfunctional pituitary adenomas on the basis of preoperative imaging. They are often hypervascular and locally adherent, which increases hemorrhage risk and limits resection, leading to increased risk of recurrence.

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Background: The costs of cervical spine surgery have steadily increased. We performed a 5-year propensity scoring-matched analysis of 276 patients undergoing anterior versus posterior cervical surgery at one institution.

Methods: We performed propensity score matching on financial data from 276 patients undergoing 1-3 level anterior versus posterior cervical fusions for degenerative disease (2015-2019).

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Introduction: Surgery can be an effective treatment for epilepsy if the seizure onset is adequately localized. Invasive monitoring is used if noninvasive methods are inconclusive. Initial invasive monitoring may fail if the pre-surgical hypothesis regarding location of epileptic foci is wrong.

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Objective: Summarize the current evidence on efficacy and tolerability of vagus nerve stimulation (VNS), responsive neurostimulation (RNS), and deep brain stimulation (DBS) through a systematic review and meta-analysis.

Methods: We followed the Preferred Reporting Items of Systematic reviews and Meta-Analyses reporting standards and searched Ovid Medline, Ovid Embase, and the Cochrane Central Register of Controlled Trials. We included published randomized controlled trials (RCTs) and their corresponding open-label extension studies, as well as prospective case series, with ≥20 participants (excluding studies limited to children).

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Background Chronic subdural hematoma (cSDH) is predicted to become the most common intracranial neurosurgical condition by 2030. Recurrence is estimated between 5-15%, and the use of a surgical drain is associated with lower recurrence rates. The authors present their experience with six patients undergoing cSDH evacuation with an irrigating drainage system, comprising the largest single-institution group in the United States (US).

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Objective: Circumferential minimally invasive spine surgery (cMIS) for adult scoliosis has become more advanced and powerful, but direct comparison with traditional open correction using prospectively collected data is limited. The authors performed a retrospective review of prospectively collected, multicenter adult spinal deformity data. The authors directly compared cMIS for adult scoliosis with open correction in propensity-matched cohorts using health-related quality-of-life (HRQOL) measures and surgical parameters.

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Background: As a growing number of patients seek consultations for increasingly complex and costly spinal surgery, it is of both clinical and economic value to investigate the role for second opinions (SOs). Here, we summarized and focused on the shortcomings of 14 studies regarding the role and value of SOs before proceeding with spine surgery.

Methods: Utilizing PubMed, Google Scholar, and Scopus, we identified 14 studies that met the inclusion criteria that included: English, primary articles, and studies published in the past 20 years.

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Objective: Elective surgical cases generally have lower costs, higher profit margins, and better outcomes than nonelective cases. Investigating the differences in cost and profit between elective and nonelective cases would help hospitals in planning strategies to withstand financial losses due to potential pandemics. The authors sought to evaluate the exact cost and profit margin differences between elective and nonelective supratentorial tumor resections at a single institution.

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At the time of writing of this article, there have been over 110 million cases and 2.4 million deaths worldwide since the start of the Coronavirus Disease 2019 (COVID-19) pandemic, postponing millions of non-urgent surgeries. Existing literature explores the complexities of rationing medical care.

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A long-standing goal of spinal cord injury research is to develop effective repair strategies, which can restore motor and sensory functions to near-normal levels. Recent advances in clinical management of spinal cord injury have significantly improved the prognosis, survival rate and quality of life in patients with spinal cord injury. In addition, a significant progress in basic science research has unraveled the underlying cellular and molecular events of spinal cord injury.

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Objective: With the advent of minimally invasive techniques, minimally invasive spine surgery (MISS) has become a realistic option for many spine cases. This study aims to evaluate the operative and clinical outcomes of MISS for total versus subtotal tumor resection from current evidence.

Methods: A literature search was performed using the search term (Minimally invasive surgery OR MIS) AND (spine tumor OR spinal tumor).

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Background: Incidental or intentional durotomy in spine surgery is associated with a risk of cerebrospinal fluid (CSF) leakage and reoperation. Several strategies have been introduced, but the incomplete closure is still relatively frequent and troublesome. In this study, we review current evidence on spinal dural repair strategies and evaluate their efficacy.

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Background: Spinopelvic parameters have hitherto dictated much of adult spinal deformity (ASD) correction. The Roussouly classification is used for the normal adult spine. We evaluated whether a correlation would be found between the Roussouly type and the rate of revision surgery in patients with ASD undergoing circumferential minimally invasive spinal (cMIS) correction.

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Background: Recently, there has been increased interest in patient satisfaction measures such as Press Ganey and Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) surveys. In this systematic review, the spine surgery literature is analyzed to evaluate factors predictive of patient satisfaction as measured by these surveys.

Methods: A thorough literature search was performed in PubMed/MEDLINE, Google Scholar, and Cochrane databases.

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Background: This article is the first to identify the most influential articles on medulloblastoma using the citation analysis methodology.

Objective: To perform a bibliometric analysis of the 100 most-cited articles on medulloblastoma.

Methods: Using the Web of Science database, search criteria included the title-specific keyword "medulloblastoma" OR "cerebellar primitive neuroectodermal tumor (PNET)" OR "cerebellar PNET.

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Objective: Minimally invasive anterior lumbar interbody fusion surgery (MIS ALIF) is a technique that restores disc height and lumbar lordosis through a smaller exposure and less soft-tissue trauma compared to open approaches. The mini-open and laparoscopic assistance techniques are two main forms of MIS ALIF. The authors conducted a systematic review that sought to critically summarize the literature on back pain following MIS ALIF.

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Objective: High-value medical care is described as care that leads to excellent patient outcomes, high patient satisfaction, and efficient costs. Neurosurgical care in particular can be expensive for the hospital, as substantial costs are accrued during the operation and throughout the postoperative stay. The authors developed a "Safe Transitions Pathway" (STP) model in which select patients went to the postanesthesia care unit (PACU) and then the neuro-transitional care unit (NTCU) rather than being directly admitted to the neurosciences intensive care unit (ICU) following a craniotomy.

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Background: Hemifacial spasm (HFS) is a debilitating disorder characterized by intermittent involuntary movement of muscles innervated by the facial nerve. HFS is caused by neurovascular compression along the facial nerve root exit zone and can be treated by microvascular decompression (MVD). The goal was to determine rates and predictors of spasm freedom after MVD for HFS.

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Background: Responsive neurostimulation (RNS) is a closed-loop neurostimulation modality for treating intractable epilepsy in patients who are not candidates for resection. In the past, implantation of depth electrodes was done through a transoccipital approach that transverses the hippocampus. There have been no descriptions of orthogonal approaches to RNS electrode placement.

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