Risk Factor Analysis of Cryopreserved Autologous Bone Flap Resorption in Adult Patients Undergoing Cranioplasty with Volumetry Measurement Using Conventional Statistics and Machine-Learning Technique.

OBJECTIVE: Decompressive craniectomy (DC) with duroplasty is one of the common surgical treatments for life-threatening increased intracranial pressure (ICP). Once ICP is controlled, cranioplasty (CP) with reinsertion of the cryopreserved autologous bone flap or a synthetic implant is considered for protection and esthetics. Although with the risk of autologous bone flap resorption (BFR), cryopreserved autologous bone flap for CP is one of the important material due to its cost effectiveness. In this article, we performed conventional statistical analysis and the machine learning technique understand the risk factors for BFR. METHODS: Patients aged >18 years who underwent autologous bone CP between January 2015 and December 2021 were reviewed. Demographic data, medical records, and volumetric measurements of the autologous bone flap volume from 94 patients were collected. BFR was defined with absolute quantitative method (BFR-A) and relative quantitative method (BFR%). Conventional statistical analysis and random forest with hyper-ensemble approach (RF with HEA) was performed. And overlapped partial dependence plots (PDP) were generated. RESULTS: Conventional statistical analysis showed that only the initial autologous bone flap volume was statistically significant on BFR-A. RF with HEA showed that the initial autologous bone flap volume, interval between DC and CP, and bone quality were the factors with most contribution to BFR-A, while, trauma, bone quality, and initial autologous bone flap volume were the factors with most contribution to BFR%. Overlapped PDPs of the initial autologous bone flap volume on the BRF-A crossed at approximately 60 mL, and a relatively clear separation was found between the non-BFR and BFR groups. Therefore, the initial autologous bone flap of over 60 mL could be a possible risk factor for BFR. CONCLUSION: From the present study, BFR in patients who underwent CP with autologous bone flap might be inevitable. However, the degree of BFR may differ from one to another. Therefore, considering artificial bone flaps as implants for patients with large DC could be reasonable. Still, the risk factors for BFR are not clearly understood. Therefore, chronological analysis and pathophysiologic studies are needed.

Anticoagulation and Antiplatelet Agent Resumption Timing following Traumatic Brain Injury.

Traumatic brain injury (TBI) is a major global health concern. Due to the increase in TBI incidence and the aging population, an increasing number of patients with TBI are taking antithrombotic agents for their underlying disease. When TBI occurs in patients with these diseases, there is a conflict between the disease, which requires an antithrombotic effect, and the neurosurgeon, who must minimize intracranial hemorrhage. Nevertheless, there are no clear guidelines for the reversal or resumption of antithrombotic agents when TBI occurs in patients taking antithrombotic agents. In this review article, we intend to classify antithrombotic agents and provide information on them. We also share previous studies on the reversal and resumption of antithrombotic agents in patients with TBI to help neurosurgeons in this dilemma.

Fencing Knife-Induced Transorbital Penetrating Brain Injury: A Case Report.

Penetrating brain injury (PBI) is a rare type of traumatic brain injury, which accounts for 0.4% of all head trauma cases. In this study, we describe a 14-year-old male adolescent who sustained a transorbital penetrating injury caused by a fencing knife. Although the patient visited the hospital after the foreign body had been removed, we diagnosed a PBI based on identification of a linear injury trajectory extending from an orbital roof fracture to the contralateral parietal lobe, using three-dimensional reconstruction of the hemorrhage. The patient fully recovered after conservative treatment. We hope that sharing our experience will serve as a guideline for the clinical management of PBI.

A Lesson from a Measles Outbreak among Healthcare Workers in a Single Hospital in South Korea: The Importance of Knowing the Prevalence of Susceptibility.

BACKGROUND: Despite the high vaccination coverage rate, in-hospital transmission of measles continues to occur in South Korea. We present a measles outbreak in which two healthcare workers (HCWs) with presumptive evidence of measles immunity were infected by a patient with typical measles at a single hospital in South Korea. This facilitated the evaluation of measles seroprevalence in all HCWs. METHODS: In 2018, suspected patients and contacts exposed during a measles outbreak were investigated based on their medical histories and vaccination status. Cases were confirmed by the detection of measles-specific immunoglobulin M or RNA. After the measles outbreak in 2018, measles IgG testing was conducted on a total of 972 HCWs for point-prevalence, including those exposed to the measles. In addition, we have routinely performed measles IgG tests on newly employed HCWs within one week of their hire date since 2019. The measles vaccine was administered to HCWs who tested negative or equivocally negative for IgG antibodies. RESULTS: An index patient who returned from China with fever and rash was diagnosed with measles at a hospital in Korea. Two additional HCWs were revealed as measles cases: one was vaccinated with the two-dose measles-mumps-rubella (MMR) vaccine, and the other, who was born in 1967, was presumed to have immunity from natural infection in South Korea. All three patients harbored the same D8 genotype. No additional measles cases were identified among the 964 contacts of secondary patients. A total of 2310 HCWs, including those tested during the 2018 outbreak, underwent measles IgG tests. The average age at the time of the test was 32.6 years, and 74.3% were female. The overall seropositivity of measles was 88.9% (95% confidence interval, 87.5-90.1). Although the birth cohorts between 1985 and 1994 were presumed to have received the measles-rubella (MR) catch-up vaccination in 2001, 175 (89.3%) HCWs were born after 1985 among the 195 seronegative cases. CONCLUSION: Despite high population immunity, imported measles transmission occurred among HCWs with presumed immunity. This report underscores the importance of understanding the prevalence of measles susceptibility among newly employed HCWs. This is important for policymaking regarding hospital-wide vaccinations to prevent the spread of vaccine-preventable diseases.

Interpreting changes in consecutive laboratory results: clinician's perspectives on clinically significant change.

BACKGROUND: Clinical laboratory tests are inevitably affected by various factors. Therefore, when comparing consecutive test results, it is crucial to consider the inherent uncertainty of the test. Clinical laboratories use reference change value (RCV) to determine a significant change between 2 results. Whereas the criteria for the interpretation of consecutive results by clinicians are not well known. We investigated the clinician's interpretation of a clinically significant change in consecutive laboratory test results and compared them to RCV. METHODS: We performed a questionnaire survey on clinicians, which comprised 2 scenarios with 22 laboratory test items suggesting initial test results. Clinicians were asked to choose a result showing clinically significant change. RCV of the analytes from EFLM database were collected. RESULTS: We received 290 valid questionnaire responses. Clinicians' opinions on clinically significant change was inconsistent between clinicians and scenarios, and was generally larger than RCV. Clinicians commented that they were not familiar with the variability of the laboratory tests. CONCLUSIONS: Clinicians' opinions on clinically significant changes were more prominent than RCV. Meanwhile, they tended to neglect the analytical and biological variation. Laboratories should properly guide clinicians on the RCV of tests for better decision-making on patients' clinical states.

Status of Pre-analytical Quality Management of Laboratory Tests at Primary Clinics in Korea.

Background: The quality of laboratory test results is crucial for accurate clinical diagnosis and treatment. Pre-analytical errors account for approximately 60%-70% of all laboratory test errors. Laboratory test results may be largely impacted by pre-analytical phase management. However, primary care clinics currently do not have pre-analytical quality management audit systems. We aimed to understand the current status of pre-analytical quality management in laboratory medicine in Korean primary care clinics. Methods: Questionnaires were designed to focus on essential components of the pre-analytical process of primary care clinics. An online survey platform was used to administer the survey to internal medicine or family medicine physicians in primary care clinics. Results: A total of 141 physicians provided a complete response to the questionnaire. In 65.2% of the clinics, patient information was hand-labeled rather than barcoded on the specimen bottles; 14.2% of clinics displayed only one piece of patient information (name or identification number), and 19.9% of clinics displayed two pieces of information. Centrifuges were not available in 29.1% of the clinics. Institutions carrying out the National Health Screening Program (NHSP) used more barcode system and had more centrifuges than institutions that did not carrying out the NHSP. Conclusions: Pre-analytical quality management is inadequate in many primary clinics. We suggest implementation of a mandatory management system, allowing for a pre-analytical quality management to be carried out in primary care clinics.

Is Fetal-Type Posterior Cerebral Artery a Risk Factor for Recurrence in Coiled Internal Carotid Artery-Incorporating Posterior Communicating Artery Aneurysms? Analysis of Conventional Statistics, Computational Fluid Dynamics, and Random Forest With Hyper-Ensemble Approach.

BACKGROUND: The fetal-type posterior cerebral artery (FPCA) has been regarded as the risk factor for recurrence in coiled internal carotid artery-incorporating posterior communicating artery (ICA-PCoA) aneurysm. However, it has not been proven in previous literature studies. OBJECTIVE: To reveal the impact of FPCA on the recurrence of ICA-PCoA aneurysms using conventional statistical analysis, computational fluid dynamics (CFD) simulation, and random forest with hyper-ensemble approach (RF with HEA). METHODS: Vascular parameters and clinical information from patients who underwent coil embolization ICA-PCoA aneurysms from January 2011 to December 2016 were obtained. Conventional statistical analysis was applied to a total of 95 cases obtained from patients with a follow-up of more than 6 months. For CFD simulation, 3 sets of three-dimensional models were used to understand the hemodynamical characteristics of various FPCAs. The RF with HEA was applied to reinforce the clinical data analysis. RESULTS: The conventional statistical analysis fails to reveal that FPCA is a risk factor. CFD analysis shows that the diameter of FPCA alone is less likely to be a risk factor. The RF with HEA shows that the impact of FPCA is also minor compared with that of the packing density in the recurrence of coiled ICA-PCoA aneurysms. CONCLUSION: The gathered results of all 3 analyses show more clear evidence that FPCA is not a risk factor for coiled ICA-PCoA aneurysms. Hence, we may conclude that FPCA itself is doubtful to be the major risk factor in the recurrence of coiled ICA-PCoA aneurysms.

Pharmacological Management of Germinal Matrix-Intraventricular Hemorrhage.

Germinal matrix-intraventricular hemorrhage (GM-IVH) is among the devastating neurological complications with mortality and neurodevelopmental disability rates ranging from 14.7% to 44.7% in preterm infants. The medical techniques have improved throughout the years, as the morbidity-free survival rate of very-low-birth-weight infants has increased; however, the neonatal and long-term morbidity rates have not significantly improved. To this date, there is no strong evidence on pharmacological management on GM-IVH, due to the limitation of well-designed randomized controlled studies. However, recombinant human erythropoietin administration in preterm infants seems to be the only effective pharmacological management in limited situations. Hence, further high-quality collaborative research studies are warranted in the future to ensure better outcomes among preterm infants with GM-IVH.

Collaborative Study to Establish National Reference Standards for Anti-HIV-1 Antibody.

Background: National reference standards for anti-HIV-1 antibody are needed to evaluate the performance and maintain the quality control of anti-HIV-1 antibody assays. The aim of this study was to prepare a mixed-titer performance panel and assess its suitability as a national reference standard for anti-HIV-1 antibody according to stability, collaboration, and other studies. Methods: Nineteen serum samples from different HIV patients were obtained, along with 15 units of fresh frozen plasma samples with negative anti-HIV-1 antibody results. Ten anti-HIV-1 antibody-positive candidate standards and two negative candidate standards were prepared based on the reactivity in the Alinity i HIV Ag/Ab combo assay (Abbott Laboratories, Wiesbaden, Germany). A collaborative study was conducted across eight laboratories using five anti-HIV-1 antibody assays. Real-time and accelerated stability were evaluated to assess the long-term stability. Results: In the collaborative study, results of all five anti-HIV-1 antibody assays were positive for all 10 candidate standards prepared using HIV patient samples. The CV of each assay for every candidate standard was within 10%, except for one assay result. No real-time and accelerated stability change trend was observed at -70°C or -20°C, supporting that the reference standards were maintained in a stable state at -70°C for long-term storage. Conclusions: The overall results suggest that the 12 candidate standards could serve as national reference standards for anti-HIV-1 antibody.

White Cord Syndrome: A Reperfusion Injury Following Spinal Decompression Surgery.

Reperfusion injury of the spinal cord has been scarcely reported. Herein, we present a case of white cord syndrome after spinal decompression. A 61-year-old male, who initially had ossification of the posterior longitudinal ligament at C3-6 level, was admitted to our hospital with a ruptured disc at the C6-7 level. The patient experienced radiating pain in both upper extremities. Anterior cervical discectomy and fusion was performed. However, the patient developed quadriplegia. Emergency magnetic resonance imaging revealed a new and enlarged signal change in the spinal cord at the C4-7 level. Additional posterior decompression surgery was performed. After intense rehabilitation, the patient's motor function improved to grade 4. White cord syndrome is likely due to reperfusion injury following operative decompression of a compressed spinal cord segment. Although rare, spine surgeons should be aware of this complication and warn patients preoperatively.

Angiographic Follow-Up for Small Ruptured Intracranial Aneurysm Treated by Endovascular Treatment : Follow-Up Plan and Long-Term Follow-Up Results.

OBJECTIVE: Although endovascular treatment for intracranial aneurysms is considered effective and safe, its durability is still debated. Also, few studies have described angiographic follow-up plan after endovascular treatment of intracranial aneurysm, especially in ruptured cases. Hence, we report the long-term results of follow-up angiography protocol. METHODS: Radiological records of 639 cases of coil embolization with ruptured aneurysms from March 2003 to December 2016 were retrospectively reviewed. Patients who received treatment of a saccular aneurysm less than 7 mm resulted with near complete occlusion were included. Two hundred thirty-eight aneuryms which received the follow-up angiography at least once were enrolled. We classified four periods of follow-up as follows : post-treatment 1 year (defined as the first period), from 1 to 2 years (the second period), 2 to 5 years (the third period), and over 5 years (long-term). RESULTS: We identified 14 cases (6.4%) of recurrence from 218 aneurysms in follow-up angiography in the first period. Among 143 aneurysms in the second period, five cases (3.5%) of recurrence were identified. There were no findings suspicious of recanalization in 97 patients in the third period. Of the total 238 cases, there were 19 recurrences, for a recurrence rate of 8.0%. Six (31.6%) out of 19 recurrences showed a tendency toward repeat recurrences even after additional treatment. Twenty-eight received long-term follow-up over 5 years and there was no recurrence. CONCLUSION: Most of the recurrence were found during the first and the second year. We suggest that at least one digital subtraction angiography examination may be necessary around post-treatment 2 years, especially in ruptured cases. If the angiographic results are favorable at 2 years post-treatment, long-term result should be favorable.

Comparison between polynomial regression and weighted least squares regression analysis for verification of analytical measurement range.

OBJECTIVES: Recently, the linearity evaluation protocol by the Clinical & Laboratory Standards Institute (CLSI) has been revised from EP6-A to EP6-ED2, with the statistical method of interpreting linearity evaluation data being changed from polynomial regression to weighted least squares linear regression (WLS). We analyzed and compared the analytical measurement range (AMR) verification results according to the present and prior linearity evaluation guidelines. METHODS: The verification of AMR of clinical chemistry tests was performed using five samples with two replicates in three different laboratories. After analyzing the same evaluation data in each laboratory by the polynomial regression analysis and WLS methods, results were compared to determine whether linearity was verified across the five sample concentrations. In addition, whether the 90% confidence interval of deviation from linearity by WLS was included in the allowable deviation from linearity (ADL) was compared. RESULTS: A linearity of 42.3-56.8% of the chemistry items was verified by polynomial regression analysis in three laboratories. For analysis of the same data by WLS, a linearity of 63.5-78.3% of the test items was verified where the deviation from linearity of all five samples was within the ADL criteria, and the cases where the 90% confidence interval of all deviation from linearity overlapped the ADL was 78.8-91.3%. CONCLUSIONS: Interpreting AMR verification data by the WLS method according to the newly revised CLSI document EP6-ED2 could reduce laboratory workload, enabling efficient laboratory practice.

Nationwide Survey for Current Status of Laboratory Diagnosis of Clostridioides difficile Infection in Korea.

BACKGROUND: The interest in Clostridioides difficile infection (CDI) has increased, and the choice of assays became wider since the first national survey in Korea on CDI diagnosis in 2015. We conducted a survey of the domestic CDI assays with more varied questions to understand the current situation in Korea. METHODS: In April 2018, about 50 questions on the current status of CDI assays and details on implementation and perceptions were written, and a survey questionnaire was administered to laboratory medicine specialists in 200 institutions. RESULTS: One-hundred and fifty institutions responded to the questionnaire, of which 90 (60.0%) including one commercial laboratory, performed CDI assays. The toxin AB enzyme immunoassay (toxin AB EIA), nucleic acid amplification test (NAAT), and C. difficile culture, glutamate dehydrogenase assay, alone or in combination with other assays, were used in 75 (84.3%), 52 (58.4%), 35 (36.0%), and 23 (25.8%), respectively, and 65 (73.0%) institutions performed a combination of two or more assays. The sensitivity of toxin AB EIA was more negatively perceived, and that on specificity was more positively perceived. The perception of sensitivity and specificity of NAAT was mostly positive. Perception on the algorithm test projected it as useful but in need of countermeasures. Sixty-three (73.3%) institutions responded that they performed surveillance on CDI. CONCLUSION: This study provides useful evidence on the current status of CDI laboratory diagnosis in Korea as well as on items that require improvement and is thought to aid in standardizing and improving the CDI laboratory diagnosis in Korea.

Comparison of Visual Outcomes of Ophthalmic Artery Aneurysms Treated with Microsurgical Clipping and Endovascular Coiling.

PURPOSE: Post-treatment visual deficit is a major concern associated with both microsurgical clipping and endovascular coiling for the treatment of ophthalmic artery (OphA) aneurysms of the internal carotid artery. We aimed to compare the safety and effectiveness of the 2 modalities. MATERIALS AND METHODS: We retrospectively reviewed and compared the baseline characteristics and postoperative visual and angiographic outcomes of OphA aneurysms treated by clipping or coiling between January 2010 and August 2018 at our hospital. In addition, the balloon occlusion test was performed to evaluate the safety of OphA occlusion. RESULTS: This study included 56 aneurysms treated by clipping and 82 aneurysms treated by coiling. Both the immediate and follow-up rates of incomplete aneurysm occlusion were comparable between the 2 groups (21.4% vs. 22.0%; 24.4% vs. 23.6%). The incidence of post-treatment visual deficits was higher in the clipping group than in the coiling group (16.1% vs. 2.4%; P=0.010). We observed total ipsilateral OphA occlusion in 6 patients and near occlusion in 3 patients during endovascular coiling; however, only 1 patient with near OphA occlusion showed a post-treatment visual field defect. CONCLUSION: OphA aneurysms treated by endovascular coiling exhibited an aneurysm occlusion rate similar to that of microsurgical clipping with fewer post-treatment visual deficits. The total occlusion of OphA with adequate collaterals did not cause post-treatment visual deficits.

Vivax malaria detection using a parasitic red blood cell flag generated by the Sysmex XN-9000 hematology analyzer.

INTRODUCTION: A Sysmex XN-series hematology analyzer (Sysmex), the next generation up from the Sysmex XE-series, can provide information regarding malaria infection in the form of a parasitic red blood cell (pRBC) flag. This study aimed to determine the usefulness of the pRBC flag for early detection and follow-up in patients infected with Plasmodium vivax. METHODS: A total of 221 patients with fever for whom CBC and malaria microscopy had been requested were analyzed. Sixty-seven individuals were diagnosed with P vivax infection, and 154 were diagnosed with other febrile diseases. The sensitivity and specificity of the pRBC flag for malaria parasite detection and the relationship between parasite density and presence of the pRBC flag were determined. The concordance rate between malaria microscopy and pRBC flag in 147 follow-up cases was calculated. RESULTS: The pRBC flag was detected in 56 of 67 malaria patients (sensitivity, 83.6%; specificity, 100%). The patients with the pRBC flag at initial diagnosis revealed significantly higher parasite density than the patients without the pRBC flag (P < .05). The concordance rate between malaria microscopy and pRBC flag in the follow-up cases was 53.1%. CONCLUSION: Considering its high sensitivity in malaria-suspicious patients, unexpected vivax malaria cases can be detected with the pRBC flag when CBC is done in a routine laboratory setting. The pRBC flag provided by the Sysmex XN series is a valuable tool for vivax malaria detection.

Turbulence Intensity as an Indicator for Ischemic Stroke in the Carotid Web.

OBJECTIVE: Carotid web (CaW) is reported as one of the causes of cryptogenic strokes. However, its pathophysiology is not known, which makes clinicians debate CaW treatment. The current study presents the mechanism of ischemic stroke in CaW and finds a potential indicator for ischemic stroke in CaW. METHODS: Computational fluid dynamics (CFD) was applied to computer-aided artificial human CaW models to investigate the correlation between stenosis rate and CaW angle. The CFD results were compared with stroke or symptomatic CaW including adequate reported images for anatomic analysis of the stenosis rate and CaW angle. RESULTS: The CFD result of the CaW models shows that the velocity decreases and the turbulence generation of blood flow increases in the area under CaW (AuCaW). In AuCaW, turbulence intensity (TI) is high in the high stenosis rate and small angle conditions. Moreover, TI remained high in the AuCaW throughout the cardiac cycles. The analysis of 67 anatomic figures appeared in 36 articles merged with CFD results, and a CaW scoring system was introduced for clinicians to determine patients with CaW with a high risk of ischemic stroke. CONCLUSIONS: This study is believed to be the first to apply TI to CaW. Because most ischemic strokes in CaW occurred at a high stenosis rate and small angle, TI may be used as a potential indicator of ischemic stroke in CaW. Furthermore, TI is easily used in the daily clinical field by applying CaW scores.

An Efficient Method for Aneurysm Volume Quantification Applicable in Any Shape and Modalities.

OBJECTIVE: Aneurysm volume quantification (AVQ) using the equation of ellipsoid volume is widely used although it is inaccurate. Furthermore, AVQ with 3-dimensional (3D) rendered data has limitations in general use. A novel universal method for AVQ is introduced for any diagnostic modality and application to any shape of aneurysms. METHODS: Relevant AVQ studies published from January 1997 to June 2019 were identified to determine common methods of AVQ. The basic idea is to eliminate the normal artery volume from 3D model with the aneurysm. After Digital Imaging and Communications in Medicine (DICOM) data is converted and exported to stereolithography (STL) file format, the 3D STL model is modified to remove the aneurysm and the volume difference between the 3D model with/without the aneurysm is defined as the aneurysm volume. Fifty randomly selected aneurysms from DICOM database were used to validate the different AVQ methods. RESULTS: We reviewed and categorized AVQ methods in 121 studies. Approximately 60% used the ellipsoid method, while 24% used the 3D model. For 50 randomly selected aneurysms, volumes were measured using 3D Slicer, RadiAnt, and ellipsoid method. Using 3D Slicer as the reference, the ratios of mean difference to mean volume obtained by RadiAnt and ellipsoid method were -1.21±7.46% and 4.04±30.54%, respectively. The deviations between RadiAnt and 3D Slicer were small despite of aneurysm shapes, but those of ellipsoid method and 3D Slicer were large. CONCLUSION: In spite of inaccuracy, ellipsoid method is still mostly used. We propose a novel universal method for AVQ that is valid, low cost, and easy to use.

Timing of Thrombosis in Embolization of Unruptured Intracranial Aneurysms : Tirofiban as Rescue Treatment.

PURPOSE: Thrombosis is one of the main complications of endovascular treatment for unruptured intracranial aneurysms (UIA). This article reports the timing and initial location of thrombosis and prognosis after the use of tirofiban for performing coil embolization for UIA. METHODS: This study retrospectively collected 1686 cases of intracranial aneurysms treated with coil embolization from January 2013 to February 2018. Ruptured cases were excluded. The presumed causes and timing of thrombosis, the response after tirofiban administration and the modified Rankin scale (mRS) score at 3 months were reviewed. RESULTS: Of the 26 patients 76% were female and middle cerebral artery and basilar artery aneurysms accounted for 7 cases. The initial location of thrombosis was related to the stent (n = 14, 53.8%) or coil (n = 12, 46.2%). Of the patients 19 (73.1%) developed thrombosis during the procedure, and 5 patients (19.2%) developed it within 1 day of the procedure. Median duration between the thrombotic procedure and initial thrombosis was 38.5 min, 12 patients were symptomatic but more than half completely recovered after using tirofiban. Good clinical outcome (mRS 0-2) was seen in 92.3%. In the subgroup analysis, median time from the first thrombotic procedure to initial thrombosis within 1 day was 38.0 min (stent-related group) and 35.0 min (coil-related group, p = 0.651). CONCLUSION: In most cases of embolization for UIA, thrombosis requiring the use of tirofiban occurs intraprocedurally or on the first day after the procedure. Careful observation of thrombosis during the procedure is important and tirofiban should be used for a better outcome even if the infarction progresses.