bluuebunny/crossref_metadata_2025 huggingface dataset:
Utilization Pattern of Personal Protective Equipment among Industrial Workers of Nawalparasi, Nepal
Authors: Acharya Shiva Raj
Published: January 2015

Introduction: With industrialization, radical alterations in the life of many rapidly developing countries are visible. Lack of well designed and appropriate safety measures leads to serious adverse health consequences to the workforce. The concept of occupational safety and health is still new in Nepal. The main objective of the study was to assess the utilization of personal protective equipment among industrial workers in Chaudhary Group Industrial Estate, Nawalparasi.Methods: A descriptive, cross-sectional study was carried out among 187 workers of five industries (Beer, Rio, Chesseball, Chips and Wafer) of Chaudhary Group Industrial Estate, Nawalparasi.Results: Mean age of the workers involved was 34.09 years (SD: ±8.650). Nine out of ten (87.2%) workers used any kind of PPE while working in worksite. Association of use of personal protective equipment with gender and encourage to use of personal protective equipment were statistically significant while income, educational status, age and working experience remained insignificant.Conclusion: Majority of the workers used the personal protective equipment in Chaudhary Group of Industry. All workers of the industry should be aware on the use of personal protective equipment to get protected from any kind of adverse health effects/hazards during while working in the industry.DOI: http://dx.doi.org/10.3126/hprospect.v13i2.11833
A simple procedure for estimating SN-lines for crack initiation from SN-lines for total failure*
Authors: Sonsino Cetin Morris
Published: January 2015

A simple procedure is proposed for estimating the SN-line for the failure criterion of fatigue life to crack initiation of components not subjected to a surface treatment. The prerequisite is the availability of a SN-line for total failure, i. e. rupture, with the scatter-band Tσ between the probabilities of survival Ps = 10 and 90 %, the knee point Nk and the slopes kf and k* before and after the knee point. The SN-line for crack initiation with Ps = 50 % is positioned at the knee point Nk of the SN-line with Ps = 90 % for total failure. The slope kcr for N < Nk cycles results from the exponent of the elastic portion of the strain controlled SN-line for crack initiation, obtained with unnotched specimens, and the slope k* after the knee point remains the same as that for the line for total failure. The SN-line for crack initiation possesses the same scatter-band Tσ as the line for total failure.
Design, manufacture and analysis of composite epoxy material with embedded silicon carbide (SiC) and alumina (Al2O3) nanoparticles/fibers
Authors: Aldosari Saad M. , Hedia Hassan S. , Hamed Mostafa A. , Khashaba Usama A.
Published: January 2015

The main objective of the presented study is to improve the performance of composite structures by introducing nanoparticles/fibers in the epoxy resin. The literature on this issue showed shortcomings in the investigations of such materials. Most of the investigations in this field are to enhance the mechanical properties of epoxy materials, which cannot be used alone for high performance structural applications due to their low mechanical properties. In the present work, the epoxy resin was modified with these different types of nanofillers such as silicon carbide (SiC) and alumina (Al2O3) nanoparticles. The nanophased epoxy was used to fabricate different types of nanocomposites as well as nano-hybridized glass fiber reinforced composite laminates. Therefore, nine different advanced materials have been fabricated including two nanocomposite materials (SiC/E and Al2O3/E), two quasi-isotropic nano-hybridized composite laminates (QI-GFR/SiC/E and QI-GFR/Al2O3/E), two unidirectional nano-hybridized composite laminates (UD-GFR/SiC/E and UD-GFR/Al2O3/E), and three control panels manufactured without nanofillers (neat epoxy, QI-GFR/E, UD-GFR/E). The materials were characterized under tension and compression. The results showed improvements in the tensile and compressive properties (strength and modulus) of the fabricated nanocomposites (SiC/E, and Al2O3/E) compared with neat epoxy. The hybridized composite laminate with Al2O3 showed high improvements in its mechanical properties compared to the composite laminates without nanofillers. In contrast, discouraging mechanical properties were observed for SiC hybridized composite laminate. Due to the many variables studied in the present work, the literature list will be long. The investigated parameters include nanofillers, nanocomposites, nano-hybridized advanced composite laminates, mechanical properties, glass transition temperature (Tg), bolted joint parameters and sonication parameters.
Effect of heat treatment on microstructure and mechanical properties of Fe-5Cr-1.4B alloy
Authors: Gu Jian , Fu Hanguang , Lei Yongping , Ma Shengqiang
Published: January 2015

The microstructures and mechanical properties of a Fe-Cr-B alloy containing 1.4 wt.-% B and 5.0 wt.-% Cr were researched after different heat treatment processes. The results indicate that the as-cast microstructure of the Fe-5Cr-1.4B alloy consists of M2B (M = Fe, Cr), M7(C,B)3, α-Fe and γ-Fe. The netlike eutectic M2B phase is distributed in the matrix. After water quenching, the netlike eutectic M2B phase begins to fracture, the metallic matrix transforms into martensite and secondary M23(C,B)6 borocarbides are precipitated. When the quenching temperature exceeds 1050 °C, the number of precipitated secondary borocarbides is reduced. After quenching, the macro- and microhardness of the samples increase with the increase of temperature, and the hardness reaches a maximum value at 1050 °C. When the temperature exceeds 1050 °C, the hardness value will slightly decrease. After tempering treatment, the matrix precipitates as miniature secondary borocarbides, and the martensite begins to soften, and the hardness is lower compared to that quenched by heat treatment. The decreasing hardness tendency becomes more pronounced with the increase of the tempering temperature. Moreover, the impact toughness reaches its maximum value (7.35 J × cm−2) when the tempering temperature ranges at 500 °C.
A discrete dislocation technique for fatigue microcracks (Part I)
Authors: Močilnik Vinko , Gubeljak Nenad
Published: January 2015

The present contribution in two continuations summarizes the contents and findings from the latest articles in the field of numerical modeling of initiation and the propagation of micro-cracks within crystalline material by the method of discrete dislocations. The discrete nature of the phenomenon of crack initiation in the crystal grain lattice, the fatigue crack propagation within the crystalline grains and theinfluence of the vicinity of the grain boundary on its propagation and its arrest were discussed, respectively. In accordance with the method of discrete dislocations, an explanation of the reasons for lifetime increase of torsion subjected specimens was provided. The lifetime of the specimens was increased by means of pre-stress compression in axial direction.
Surface roughness analysis and optimization for the CNC milling process by the desirability function combined with the response surface methodology
Authors: Esme Ugur
Published: January 2015

The present study is aimed for an optimization strategy for the CNC pocket millingprocess based on the desirability function approach (DFA) combined with the response surface methodology (RSM). Firstly, the milling parameters such as cutting speed, feed rate and depth of cut are designed using the rotatable central composite design (CCD). The AISI 1050 medium carbon steel is machined by a flat end 8 mm high speed steel (HSS) tool on a zigzag cutting path under air flow condition. The influence of milling parameters is examined. Secondly, the model for the surface roughness, as a function of milling parameters, is obtained using the RSM. Finally, the power and adequacy of the quadratic mathematical model has been proven by the analysis of variance (ANOVA) method. The results indicate that the feed rate is the dominant factor affecting the surface roughness, which is minimized when the feed rate and depth of cut are set to the experimental range. A high correlation coefficient of R2 = 0.99 has been obtained between the predicted and the experimental surface roughness. This reveals that the prediction system established in this study produces satisfactory results with an improved performance compared to other models in the literature. The enhanced method proposed in this study can be readily applied to different metal cutting processes with greater confidence.
Performance of organic and inorganic substances as inhibitors for chloride-induced corrosion in concrete
Authors: Aydin Özlem , Çizmeciglu Zeki
Published: January 2015

Studies have been carried out to investigate the concrete corrosion inhibitor performance of silica fume admixture and an admixture of amino alcohols containing organic and inorganic substances. The concrete specimens with and without admixtures were subjected to accelerated corrosion tests to determine the time to corrosion initiation. The results showed that the specimens admixtured with nitrogen containing organic and inorganic inhibitors performed slightly better than concrete specimens with silica fume admixture.
Modellbasierte Korrelation zwischen dem elektrischen Widerstand und der Versetzungsstruktur des ermüdungsbeanspruchten ICE-Radstahls R7
Authors: Starke Peter , Walther Frank
Published: January 2015

Kurzfassung

Eine gewichtsoptimierte Bauteilauslegung und ausfallsichere Abschätzung der Lebensdauer metallischer Werkstoffe sowie Bauteile setzen ein umfassendes Verständnis der Ermüdungsvorgänge und eine systematische Untersuchung des Ermüdungsverhaltens voraus. Dies wird umso bedeutender, wenn es um die Auslegung hochbeanspruchter komplexer Bauteilgeometrien geht, wie sie im Rad-Schiene-System im Hochgeschwindigkeitspersonenverkehr eingesetzt werden. Zur Charakterisierung des Ermüdungsverhaltens und der strukturmechanischen Prozesse werden üblicherweise mechanische Spannungs-Dehnungs-Hysteresis-Messungen, aber zunehmend auch verschiedene Arten von Temperatur- und elektrischen Widerstandsmessungen eingesetzt. Insbesondere die elektrische Widerstandsmessung führt zu einem wesentlichen Informationsgewinn, da bereits mikrostrukturelle Veränderungen detektiert werden können, die z. B. auf Veränderungen der Versetzungsdichte und -struktur beruhen. Zudem können diese resistiven Messverfahren auch in Einstufenversuchen mit lastfreien Unterbrechungen und in Betriebslastversuchen zur Charakterisierung des Schädigungsverlaufs herangezogen werden. Im Rahmen dieses Artikels wurden für den ICE-Vollradstahl R7 Kennwerte der (spezifischen) elektrischen Widerstandsänderung ermittelt und beanspruchungs- bzw. lastspielzahlabhängig mit der Veränderung der röntgenografisch ermittelten Versetzungsdichte korreliert.
Applying quadraphonic transmission ultrasonic defectoscopy on standard aluminum materials
Authors: Ebersold Zoran , Ćosović Nemanja , Đukić Slobodan , Mitrović Nebojša , Obradović Dragiša
Published: January 2015

Quadraphonic transmission ultrasonic defectoscopy (QTUD) is a new method of ultrasound. This paper presents a detailed and systematic view of the measuring procedure that enables the discovery of a necessary optimal balance between, on the one side, efficiency and reliability of the QTUD measuring system, and on the other, minimizing the investment costs in the measuring components precision. This type of defectoscope applies relatively low frequencies of just a few tens of kilohertz that enable the necessary signal penetration during the measuring procedure. This paper shows a defectoscopic examination of the standard aluminum material AlMg3 with a defect that has been purposely created in need of developing the QTUD measuring procedure, whereby varied wave forms and the amplitude levels of signal have been used for the purpose of their optimization.
Fast microwave synthesis and characterization of MgTi2O5
Authors: Çelik Gülşah , Kurtuluş Figen
Published: January 2015

Magnesium dititanate, MgTi2O5 was obtained via a microwave synthesis method. Powder X-ray diffraction, infrared spectroscopy and thermogravimetric/differantial thermal analysis measurements have been used to characterize the sample.
Rapid synthesis of Mn3O4 powder from pyro-synthesis of ethylene glycol–metal nitrate precursor assisted by nitric acid
Authors: de Abreu Dias Cristiane , Nobre Marcos A. L. , Lopes Mauro C.
Published: January 2015

The rapid synthesis of Mn3O4 powders by a two-step process of pyro-synthesis of ethylene glycol–metal nitrate precursor assisted by nitric acid is reported. A new strategy that accelerates the synthesis and allows obtaining highly pure crystalline Mn3O4 is discussed. The structural and morphological characteristics of the Mn3O4 powders are presented and discussed. The mechanism of formation of the Mn3O4 is also discussed. In comparison with other synthesis methods, the present method shows that the proposed route of synthesis has the main advantage of high production of the powder material in a very short time.
Gamma Knife radiosurgery for meningiomas in patients with neurofibromatosis Type 2
Authors: Liu Ann , Kuhn Elizabeth N. , Lucas John T. , Laxton Adrian W. , Tatter Stephen B. , Chan Michael D.
Published: January 2015

OBJECT

Neurofibromatosis Type 2 (NF2) is a rare autosomal dominant disorder predisposing patients to meningiomatosis. The role of stereotactic radiosurgery (SRS) is poorly defined in NF2, and although the procedure has excellent control rates in the non-NF2 population, its utility has been questioned because radiation has been hypothesized to predispose patients to malignant transformation of benign tumors. To the authors' knowledge, this is the first study to examine the use of SRS specifically for meningiomas in patients with NF2.

METHODS

The authors searched a tumor registry for all patients with NF2 who had undergone Gamma Knife radiosurgery (GKRS) for meningioma in the period from January 1, 1999, to September 19, 2013, at a single tertiary care cancer center. Medical records were retrospectively reviewed for patient and tumor characteristics and outcomes.

Results

Among the 12 patients who met the search criteria, 125 meningiomas were identified, 87 (70%) of which were symptomatic or progressive and thus treated with GKRS. The median age at the first GKRS was 31 years (interquartile range [IQR] 27–37 years). Five patients (42%) had multiple treatments with a median of 27 months (IQR 14–50 months) until the subsequent GKRS. The median follow-up in surviving patients was 43 months (IQR 34–110 months). The 5-year local tumor control and distant treatment failure rates were 92% and 77%, respectively. Toxicities occurred in 25% of the GKRS treatments, although the majority were Grade 1 or 2. At the last follow-up, 4 patients (33%) had died a neurological death at a median age of 39 years (IQR 37–46 years), and their cases accounted for 45% of all tumors, 55% of all treated tumors, and 58% of all GKRSs. Univariate analysis revealed several predictive variables for distant failure, including male sex (HR 0.28, 95% CI 0.086–0.92, p = 0.036), age at distant failure (HR 0.92, 95% CI 0.90–0.95, p < 0.0001), and prior number of GKRS treatments (HR 1.2, 95% CI 1.1–1.4, p = 0.0049). Local failure, maximum size of the treated tumor, delivered tumor margin dose, and WHO grade were not significant. On multivariate analysis, age at distant failure (HR 0.91, 95% CI 0.88–0.95, p < 0.0001) and prior number of GKRSs (HR 1.3, 95% CI 1.1–1.5, p = 0.004) remained significant. No malignant transformation events among treated tumors were observed.

CONCLUSIONS

Radiosurgery represents a feasible modality with minimal toxicity for NF2-associated meningiomas. Increasing patient age was associated with a decreased rate of distant failure, whereas an increasing number of prior GKRS treatments predicted distant failure. Further studies are necessary to determine the long-term patterns of treatment failure in these patients.
Prognostic value of premorbid hypertension and neurological status in aneurysmal subarachnoid hemorrhage: pooled analyses of individual patient data in the SAHIT repository
Authors: Jaja Blessing N. R. , Lingsma Hester , Schweizer Tom A. , Thorpe Kevin E. , Steyerberg Ewout W. , Macdonald R. Loch
Published: January 2015

OBJECT

The literature has conflicting reports about the prognostic value of premorbid hypertension and neurological status in aneurysmal subarachnoid hemorrhage (SAH). The aim of this study was to investigate the prognostic value of premorbid hypertension and neurological status in the SAH International Trialists repository.

METHODS

Patient-level meta-analyses were conducted to investigate univariate associations between premorbid hypertension (6 studies; n = 7249), admission neurological status measured on the World Federation of Neurosurgical Societies (WFNS) scale (10 studies; n = 10,869), and 3-month Glasgow Outcome Scale (GOS) score. Multivariable analyses were performed to sequentially adjust for the effects of age, CT clot burden, aneurysm location, aneurysm size, and modality of aneurysm repair. Prognostic associations were estimated across the ordered categories of the GOS using proportional odds models. Nagelkerke's R2 statistic was used to quantify the added prognostic value of hypertension and neurological status beyond those of the adjustment factors.

RESULTS

Premorbid hypertension was independently associated with poor outcome, with an unadjusted pooled odds ratio (OR) of 1.73 (95% confidence interval [CI] 1.50–2.00) and an adjusted OR of 1.38 (95% CI 1.25–1.53). Patients with a premorbid history of hypertension had higher rates of cardiovascular and renal comorbidities, poorer neurological status (p ≤ 0.001), and higher odds of neurological complications including cerebral infarctions, hydrocephalus, rebleeding, and delayed ischemic neurological deficits. Worsening neurological status was strongly independently associated with poor outcome, including WFNS Grades II (OR 1.85, 95% CI 1.68–2.03), III (OR 3.85, 95% CI 3.32–4.47), IV (OR 5.58, 95% CI 4.91–6.35), and V (OR 14.18, 95% CI 12.20–16.49). Neurological status had substantial added predictive value greater than the combined value of other prognostic factors (R2 increase > 10%), while the added predictive value of hypertension was marginal (R2 increase < 0.5%).

CONCLUSIONS

This study confirmed the strong prognostic effect of neurological status as measured on the WFNS scale and the independent but weak prognostic effect of premorbid hypertension. The effect of premorbid hypertension could involve multifactorial mechanisms, including an increase in the severity of initial bleeding, the rate of comorbid events, and neurological complications.
Ventriculoiliac shunt: a cadaveric feasibility study
Authors: Tubbs R. Shane , Tubbs Isaiah , Loukas Marios , Cohen-Gadol Aaron A.
Published: January 2015

OBJECT

Additional distal sites for placement of CSF diversionary shunts may be necessary in some patients. The present study aimed to investigate the marrow space of the ilium as a potential receptacle for CSF in patients with hydrocephalus.

METHODS

Cannulation of the marrow space of the ilium was performed in 5 fresh human cadavers less than 4 hours from time of death. Tap water was infused via a metal trocar for approximately 60 minutes.

RESULTS

A total of 30 L of water was easily injected into all cadaveric specimens without overflow from the infusion site or noticeable edema of the body. Upon inspection of the thoracic and abdominal cavities, no fluid accumulation was identified, ensuring that all infused fluid had gone into the vascular system.

CONCLUSIONS

Based on this cadaveric study, the ilium appears to be an ideal location for placement of the distal end of a CSF diversionary shunt when other anatomical receptacles are not an option. In vivo human studies are now required to verify these findings.
Smoking as an independent predictor of reoperation after lumbar laminectomy: a study of 500 cases
Authors: Bydon Mohamad , Macki Mohamed , De la Garza-Ramos Rafael , Sciubba Daniel M. , Wolinsky Jean-Paul , Gokaslan Ziya L. , Witham Timothy F. , Bydon Ali
Published: January 2015

OBJECT

This study aimed to identify the factors predicting an increased risk for reoperation in patients who had undergone a lumbar laminectomy.

METHODS

The authors retrospectively reviewed the electronic medical records of all patients who had undergone firsttime, bilateral laminectomy at 1, 2, or 3 levels for lumbar spondylosis at the authors' institution. Patients who underwent fusion, laminotomy, discectomy, or complete facetectomy were excluded. The patients' preoperative symptoms and comorbidities were also obtained from their medical records.

RESULTS

Over an average follow-up period of 46.8 months, of 500 patients who had undergone laminectomy at 1, 2, or 3 levels, 81 patients (16.2%) developed subsequent spinal disorders that required a reoperation. A multiple logistic regression analysis identified smoking as an independent predictor of reoperation (OR 2.15, p = 0.01). Smoking was also an independent predictor of reoperation after a single-level laminectomy (OR 11.3, p = 0.02) and after a multilevel (that is, involving 2 or 3 levels) laminectomy (OR 1.98, p = 0.05). For 72 patients undergoing reoperation only for spinal degeneration, smoking remained an independent, statistically significant predictor of reoperation (OR 2.06, p = 0.04). Nine patients underwent reoperation for nondegenerative conditions (hematoma, wound infection, or wound dehiscence), and in these patients, chronic obstructive pulmonary disease was the only statistically significant predictor of reoperation (OR 8.92, p = 0.03).

CONCLUSIONS

Smoking was the strongest predictor of reoperation in patients who had undergone single-level laminectomy, multilevel laminectomy, or reoperation for progression of spinal degeneration. These findings suggest that smokers have worse outcomes of lumbar decompression than nonsmokers.
Ultrafast dynamic computed tomography myelography for the precise identification of high-flow cerebrospinal fluid leaks caused by spiculated spinal osteophytes
Authors: Thielen Kent R. , Sillery John C. , Morris Jonathan M. , Hoxworth Joseph M. , Diehn Felix E. , Wald John T. , Rosebrock Richard E. , Yu Lifeng , Luetmer Patrick H.
Published: January 2015

OBJECT

Precise localization and understanding of the origin of spontaneous high-flow spinal CSF leaks is required prior to targeted treatment. This study demonstrates the utility of ultrafast dynamic CT myelography for the precise localization of high-flow CSF leaks caused by spiculated spinal osteophytes.

METHODS

This study reports a series of 14 patients with high-flow CSF leaks caused by spiculated spinal osteophytes who underwent ultrafast dynamic CT myelography between March 2009 and December 2010. There were 10 male and 4 female patients, with an average age of 49 years (range 37–74 years). The value of ultrafast dynamic CT myelography in depicting the CSF leak site was qualitatively assessed.

RESULTS

In all 14 patients, ultrafast dynamic CT myelography was technically successful at precisely demonstrating the site of the CSF leak, the causative spiculated osteophyte piercing the dura, and the relationship of the implicated osteophyte to adjacent structures. Leak sites included 3 cervical, 11 thoracic, and 0 lumbar levels, with 86% of the leaks occurring from C-5 to T-7. Information obtained from the ultrafast dynamic CT myelogram was considered useful in all treated CSF leaks.

CONCLUSIONS

Spinal osteophytes piercing the dura are a more frequent cause of high-flow CSF leaks than previously recognized. Ultrafast dynamic CT myelography adds value beyond standard dynamic myelography or digital subtraction myelography in the diagnosis and anatomical characterization of high-flow spinal CSF leaks caused by these osteophytes. This information allows for appropriate planning for percutaneous or surgical treatment.
Classification of middle fossa floor dehiscence syndromes
Authors: Gupta Kunal , Sabry Hatem A. , Dogan Aclan , Coppa Nicholas D. , McMenomey Sean , Delashaw Johnny B. , Raslan Ahmed M.
Published: January 2015

OBJECT

Middle fossa floor dehiscence (MFFD) can present as multiple syndromes depending on dehiscence location, tissue herniation, and dural integrity. The authors propose a classification system for MFFD with the potential to guide clinical decision making.

METHODS

A retrospective analysis of the electronic medical records (years 1995–2012) of patients who had undergone temporal craniotomy for the surgical repair of an MFFD syndrome at a single institution was undertaken. Reviewed data included demographic, operative, presentation, and outcome details. Middle fossa floor dehiscence was classified as follows: Class A, bony dehiscence without herniation of the brain and/or meninges; Class B, herniation of the brain and/or meninges through the middle fossa floor without CSF leakage; Class C, dehiscence with CSF leakage without meningitis; or Class D, dehiscence with meningitis.

RESULTS

Fifty-one patients, 22 males and 29 females, were included in the analysis. The mean age was 48.7 ± 15.5 years, mean body mass index was 32.65 ± 6.86 kg/m2, and mean symptom duration was 33 ± 42 months. Seven patients underwent repeat surgery for symptomatic recurrence; therefore, there were 58 surgical encounters. Repair included bony reconstruction with hydroxyapatite with or without resection of encephaloceles and/or repair of a dural defect. According to the MFFD classification system described, 15, 8, 27, and 8 cases were categorized as Class A, B, C, and D, respectively. The prevalence of hearing loss was 87%, 63%, and 70% in Classes A, B, and C, respectively. Vestibular symptoms were more prevalent in Class A. Seven patients reported persistent symptoms at the last follow-up. Transient complications were similar in each classification (13%–25%), and a single permanent complication related to anesthesia was observed. There were no mortalities or severe neurological morbidities in the series.

CONCLUSIONS

Middle fossa floor dehiscence has a spectrum of clinical presentations. A classification system may help to clarify the diagnosis and guide therapy. Surgery, the mainstay of treatment, is safe and well tolerated.
Aspirin is associated with an increased risk of subdural hematoma in normal-pressure hydrocephalus patients following shunt implantation
Authors: Birkeland Peter , Lauritsen Jens , Poulsen Frantz Rom
Published: January 2015

OBJECT

In this paper the authors investigate whether shunt-treated patients with normal-pressure hydrocephalus receiving aspirin therapy are at increased risk of developing subdural hematoma (SDH).

METHODS

Records from 80 consecutive patients who had undergone implantation of a cerebrospinal fluid shunt for the treatment of normal-pressure hydrocephalus were retrospectively reviewed.

RESULTS

Eleven cases of symptomatic SDH occurred, all among patients receiving aspirin or clopidogrel. The 5-year survival estimate was 0.3 (p < 0.0001) for users of aspirin and the hazard ratio was 12.8 (95% CI 3.1–53).

CONCLUSIONS

Patients on an aspirin therapy regimen have a markedly increased risk of SDH after a shunt has been implanted for the treatment of normal-pressure hydrocephalus. Users of clopidogrel may have an even greater risk.
The role of microscope-integrated near-infrared indocyanine green videoangiography in the surgical treatment of intracranial dural arteriovenous fistulas
Authors: Thind Harjot , Hardesty Douglas A. , Zabramski Joseph M. , Spetzler Robert F. , Nakaji Peter
Published: January 2015

OBJECT

The successful treatment of an intracranial dural arteriovenous fistula (dAVF) requires complete obliteration of blood flow through the fistulous point. Surgical ligation is often used along with endovascular techniques. Digital subtraction angiography (DSA) can be used to confirm fistula obliteration; however, this technique can be cumbersome intraoperatively and difficult to correlate anatomically with the surgical field. Near-infrared indocyanine green (ICG) videoangiography has been described as a complementary tool for this purpose.

METHODS

The authors examined intracranial dAVF cases in which microscope-integrated intraoperative ICG videoangiography was used to identify and/or confirm obliteration of the dAVF during surgery. Retrospective evaluation of all intracranial dAVF cases treated with surgical ligation over a 10-year period at the Barrow Neurological Institute (n = 47) revealed 28 cases in which ICG videoangiography was used. The results were compared with findings on preoperative and intraoperative or postoperative DSA.

RESULTS

ICG videoangiography successfully confirmed the fistulous point intraoperatively in 96% (22/23) of the cases. It also revealed complete obliteration of fistulas, comparable to intraoperative or postoperative DSA, in 91% (21/23) of the cases. The false-negative rate of ICG was 8.7% (2/23), which is similar to the false-negative rate of intraoperative DSA alone (10.5% [2/19]).

CONCLUSIONS

Microscope-based ICG videoangiography provides real-time information about the intraoperative anatomy of dAVFs. In addition, it can confirm complete obliteration of a fistula. This technique may be useful during dAVF surgery as an independent form of angiography or as an adjunct to intraoperative or postoperative DSA.
Concussion symptoms in youth motocross riders: a prospective, observational study
Authors: Luo T. David , Clarke Michelle J. , Zimmerman Amy K. , Quinn Michael , Daniels David J. , McIntosh Amy L.
Published: January 2015

OBJECT

Action motorsports, including motocross, have been gaining popularity among children and adolescents, raising concerns for increased risk of concussions in participating youth. The authors undertook this study to test the following hypotheses: 1) that there is a high rate of concussion symptoms associated with a number of preventable or adjustable risk factors, and 2) that a high percentage of these symptoms are not be reported to adults and medical personnel.

METHODS

The authors identified all motocross riders under the age of 18 at a regional racetrack during the riding season between May and October 2010. The participants completed questionnaires pertaining to demographic characteristics and variables associated with motocross. The questionnaire results were compared with the incidence of self-reported concussion symptoms.

RESULTS

Two hundred two riders were identified who met the criteria for participation in the study, and 139 of them completed the study questionnaire. Of these 139 riders, 67 (48%) reported at least 1 concussion symptom during the season. The majority of riders (98%) reported “always” wearing a helmet, and 72% received professional help with fitting of their helmets. Proper helmet fitting was associated with a 41% decreased risk of concussion symptoms (RR 0.59, 95% CI 0.44–0.81, p < 0.01). Sixty-six riders (47%) reported having received sponsor support for motocross participation. Sponsor support conferred a relative risk for concussion symptoms of 1.48 (95% CI 1.05–2.08, p = 0.02).

CONCLUSIONS

Nearly half of all motocross competitors under the age of 18 reported concussion symptoms. Preventive measures are necessary to limit the negative impact from concussions. The risk of concussive injury can be decreased for pediatric motocross riders if they receive professional help with proper helmet fitting and through implementation of stricter guidelines regarding sponsorship.
Craniopharyngioma arising in a Rathke's cleft cyst: case report
Authors: Alomari Ahmed K. , Kelley Brian J. , Damisah Eyiyemisi , Marks Asher , Hui Pei , DiLuna Michael , Vortmeyer Alexander
Published: January 2015

Craniopharyngioma is one of the most common non-glial intracranial tumors of childhood. Its relation to Rathke's cleft cyst (RCC) is controversial, and both lesions have been hypothesized to lie on a continuum of cystic ectodermal lesions of the sellar region. The authors report on a 7-year-old boy who presented with decreased visual acuity, presumably of at least 2 years' duration, and was found to have a 5.2-cm sellar lesion with rim enhancement. Histological examination of the resected lesion showed a mixture of areas with simple RCC morphology with focal squamous metaplasia and areas with typical craniopharyngioma morphology. Immunohistochemical staining with CK20 and Ki 67 differentially highlighted the 2 morphological components. Testing for beta-catenin and BRAF mutations was negative in the craniopharyngioma component, precluding definitive molecular classification. Follow-up imaging showed minimal residual enhancement and the patient will be closely followed up with serial MRI. Given the clinical and histological findings in the case, a progressive transformation of the RCC to craniopharyngioma seems to be the most plausible explanation for the co-occurrence of the 2 lesion types in this patient. An extensive review of previously proposed theories of the relationship between craniopharyngioma and RCC is also presented.
Extensive spinal epidural abscess treated with “apical laminectomies” and irrigation of the epidural space: report of 2 cases
Authors: Abd-El-Barr Muhammad M. , Bi Wenya Linda , Bahluyen Biji , Rodriguez Samuel T. , Groff Michael W. , Chi John H.
Published: January 2015

Spinal epidural abscess (SEA) is a rare but often devastating infection of the epidural space around the spinal cord. When an SEA is widespread, extensive decompression with laminectomy is often impossible, as it may subject the patient to very long operative times, extensive blood loss, and mechanical instability. A technique called “skip laminectomy” has been described in the literature, in which laminectomies are performed at the rostral and caudal ends of an abscess that spans 3–5 levels and a Fogarty catheter is used to mechanically drain the abscess, much like in an embolectomy. In this report of 2 patients, the authors present a modification of this technique, which they call “apical laminectomies” to allow for irrigation and drainage of an extensive SEA spanning the entire length of the vertebral column (C1–2 to L5–S1).

Two patients presented with cervico-thoraco-lumbar SEA. Laminectomies were performed at the natural apices of the spine, namely, at the midcervical, midthoracic, and midlumbar spine levels. Next, a pediatric feeding tube was inserted in the epidural space from the thoracic laminectomies up toward the cervical laminectomy site and down toward the lumbar laminectomy site, and saline antibiotics were used to irrigate the SEA. Both patients underwent this procedure with no adverse effects. Their SEAs resolved both clinically and radiologically. Neither patient suffered from mechanical instability at 1 year after treatment.

For patients who present with extensive SEAs, apical laminectomies seem to allow for surgical cure of the infectious burden and do not subject the patient to extended operating room time, an increased risk of blood loss, and the risk of mechanical instability.
High occurrence of head and spine injuries in the pediatric population following motocross accidents
Authors: Daniels David J. , Clarke Michelle J. , Puffer Ross , Luo T. David , McIntosh Amy L. , Wetjen Nicolas M.
Published: January 2015

OBJECT

Off-road motorcycling is a very popular sport practiced by countless people worldwide. Despite its popularity, not much has been published on the severity and distribution of central nervous system–related injuries associated with this activity in the pediatric population. The purpose of this study was to confirm, characterize, and document the rate of head and spine injuries associated with off-road motorcycling in this population.

METHODS

All patients aged 18 years or less who were treated for a motorbike injury at the authors' institution (a Level 1 regional trauma center) between 2000 and 2007 were identified through in-house surgical and trauma registries. Type, mechanism, and severity of CNS-related injuries were assessed, including: incidence of traumatic brain injury (TBI), loss of consciousness (LOC), Glasgow Coma Scale (GCS) score, head CT findings, neurological deficits, spinal fractures, cervical strain, and use of protective gear, including helmets.

RESULTS

During the 8-year period of study, 298 accidents were evaluated in 248 patients. The patients' mean age at the time of injury was 14.2 ± 2.7 years. Head injury or TBI was identified in 60 (20.1%) of 298 cases (involving 58 of 248 patients). Fifty-seven cases were associated with LOC, and abnormalities were identified on head CT in 10 patients; these abnormalities included skull fractures and epidural, subdural, subarachnoid, and intraparenchymal hemorrhages. The GCS score was abnormal in 11 cases and ranged from 3 to 15, with an overall mean of 14.5. No patients required cranial surgery. Helmet use was confirmed in 43 (71.6%) of the cases involving TBI. Spine fractures were identified in 13 patients (4.3%) and 5 required surgical fixation for their injury.

CONCLUSIONS

The authors found a high occurrence of head injuries following pediatric off-road motorcycle riding or motocross accidents despite the use of helmets. Additionally, this study severely underestimates the rate of mild TBIs in this patient population. Our data indicate that motocross is a high-risk sport despite the use of protective gear. Riders and parents should be counseled accordingly about the risks prior to participation.
Degenerative changes in adolescent spines: a comparison of motocross racers and age-matched controls
Authors: Daniels David J. , Luo T. David , Puffer Ross , McIntosh Amy L. , Larson A. Noelle , Wetjen Nicholas M. , Clarke Michelle J.
Published: January 2015

OBJECT

Motocross racing is a popular sport; however, its impact on the growing/developing pediatric spine is unknown. Using a retrospective cohort model, the authors compared the degree of advanced degenerative findings in young motocross racers with findings in age-matched controls.

METHODS

Patients who had been treated for motocross-related injury at the authors' institution between 2000 and 2007 and had been under 18 years of age at the time of injury and had undergone plain radiographic or CT examination of any spinal region were eligible for inclusion. Imaging was reviewed in a blinded fashion by 3 physicians for degenerative findings, including endplate abnormalities, loss of vertebral body height, wedging, and malalignment. Acute pathological segments were excluded. Spine radiographs from age-matched controls were similarly reviewed and the findings were compared.

RESULTS

The motocross cohort consisted of 29 riders (mean age 14.7 years; 82% male); the control cohort consisted of 45 adolescents (mean age 14.3 years; 71% male). In the cervical spine, the motocross cohort had 55 abnormalities in 203 segments (average 1.90 abnormalities/patient) compared with 20 abnormalities in 213 segments in the controls (average 0.65/patient) (p = 0.006, Student t-test). In the thoracic spine, the motocross riders had 51 abnormalities in 292 segments (average 2.04 abnormalities/patient) compared with 25 abnormalities in 299 segments in the controls (average 1.00/patient) (p = 0.045). In the lumbar spine, the motocross cohort had 11 abnormalities in 123 segments (average 0.44 abnormalities/patient) compared with 15 abnormalities in 150 segments in the controls (average 0.50/patient) (p = 0.197).

CONCLUSIONS

Increased degenerative changes in the cervical and thoracic spine were identified in adolescent motocross racers compared with age-matched controls. The long-term consequences of these changes are unknown; however, athletes and parents should be counseled accordingly about participation in motocross activities.
Primitive neuroectodermal tumors of the brainstem in children treated according to the HIT trials: clinical findings of a rare disease
Authors: Friedrich Carsten , Warmuth-Metz Monika , von Bueren André O. , Nowak Johannes , Bison Brigitte , von Hoff Katja , Pietsch Torsten , Kortmann Rolf D. , Rutkowski Stefan
Published: January 2015

OBJECT

Primitive neuroectodermal tumors of the central nervous system (CNS-PNET) arising in the brainstem are extremely rare, and knowledge about them is limited. The few existing case series report fatal outcomes. The purpose of this study was to analyze clinical characteristics of and outcome for brainstem CNS-PNET patients treated according to the consecutive, population-based HIT studies covering a 19-year time period.

METHODS

Between September 1992 and November 2011, 6 eligible children with histologically proven brainstem CNS-PNET not otherwise specified and 2 children with brainstem ependymoblastomas (3, partial resection; 3, subtotal resection; 2, biopsy), median age 3.3 years (range 1.2–10.6 years), were treated according to consecutive multimodal HIT protocols for CNS-PNET/medulloblastoma. Postoperative treatment was according to maintenance chemotherapy protocols (3, craniospinal irradiation [CSI] followed by maintenance chemotherapy), sandwich chemotherapy protocols (2, neoadjuvant chemotherapy, CSI, maintenance chemotherapy), or a therapy protocol for children younger than 4 years (3, postoperative chemotherapy followed by CSI).

RESULTS

The median duration of prediagnostic symptoms, predominantly cranial nerve deficits (n = 7), pyramidal tract signs (n = 5), or ataxia (n = 5), was 5 weeks (range 1–13 weeks). The tumors were all located in the pons. Most involved more than half of the pontine axial diameter and were sharply marginated. All patients had postoperative residual disease, including metastasis in 1 case. With 1 exception all tumors progressed early during treatment within 3.9 months (range 2.5–10.4 months), leading to a 1-year event-free survival rate (± standard error) of 13% ± 12%. After progression, patients succumbed early to their disease resulting in a 1-year overall survival rate of 25% ± 15%. The only surviving patient had a partially resected CNS-PNET, received a sandwich chemotherapy protocol, and is without disease progression 14 months after diagnosis.

CONCLUSIONS

CNS-PNET is a rare but important differential diagnosis in childhood brainstem tumors. So far, efficient therapies are lacking. The sampling of tumor material for improved biological understanding and identification of new therapeutic targets is important.
Occipital aneurysmal bone cyst rupture following head trauma: case report
Authors: Garber Sarah T. , Riva-Cambrin Jay K.
Published: January 2015

Aneurysmal bone cysts (ABCs) are benign, expansile, osteolytic lesions that represent 1%–2% of primary bone tumors. Cranial ABCs are even more rare and represent 3%–6% of these unique lesions. The authors describe the case of a 3-year-old girl who presented with an acute posterior fossa epidural hematoma after minor trauma. Imaging workup revealed a previously undiagnosed suboccipital ABC that appeared to have ruptured as a result of her trauma, leading to a life-threatening hemorrhage. To the authors' knowledge, a ruptured ABC has never before been presented in the pediatric literature. In this case report, the authors review the imaging findings, natural history, clinical course, and treatment of these rare lesions.
Extent of collateralization predicting symptomatic cerebral vasospasm among pediatric patients: correlations among angiography, transcranial Doppler ultrasonography, and clinical findings
Authors: Moftakhar Parham , Cooke Daniel L. , Fullerton Heather J. , Ko Nerissa U. , Amans Matthew R. , Narvid Jared A. , Dowd Christopher F. , Higashida Randall T. , Halbach Van V. , Hetts Steven W.
Published: January 2015

OBJECT

Although the development and prevalence of cerebral vasospasm (CV) has been extensively investigated in adults, little data exist on the development of CV in children. The authors hypothesized that even though children have highly vasoreactive arteries, because of a robust cerebral collateral blood flow, they rarely develop symptomatic CV.

METHODS

The authors retrospectively reviewed their university hospital's neurointerventional database for children (that is, patients ≤ 18 years) who were examined or treated for aneurysmal or traumatic subarachnoid hemorrhage (SAH) during the period 1990–2013. Images from digital subtraction angiography (DSA) were analyzed for the extent of CV and collateralization of the cerebral circulation. Results from transcranial Doppler (TCD) ultrasonography were correlated with those from DSA. Cerebral vasospasm on TCD ultrasonography was defined according to criteria developed for adults. Clinical outcomes of CV were assessed with the pediatric modified Rankin Scale (mRS).

RESULTS

Among 37 children (21 boys and 16 girls ranging in age from 8 months to 18 years) showing symptoms of an aneurysmal SAH (comprising 32 aneurysms and 5 traumatic pseudoaneurysms), 17 (46%) had CV confirmed by DSA; CV was mild in 21% of these children, moderate in 50%, and severe in 29%. Only 3 children exhibited symptomatic CV, all of whom had poor collateralization of cerebral vessels. Among the 14 asymptomatic children, 10 (71%) showed some degree of vessel collateralization. Among 16 children for whom TCD data were available that could be correlated with the DSA findings, 13 (81%) had CV according to TCD criteria. The sensitivity and specificity of TCD ultrasonography for diagnosing CV were 95% and 59%, respectively. The time to CV onset detected by TCD ultrasonography was 5 ± 3 days (range 2–10 days). Twenty-five (68%) of the children had good long-term outcomes (that is, had mRS scores of 0–2).

CONCLUSIONS

Children have a relatively high incidence of angiographically detectable, moderate-to-severe CV. Children rarely develop symptomatic CV and have good long-term outcomes, perhaps due to robust cerebral collateral blood flow. Criteria developed for detecting CV with TCD ultrasonography in adults overestimate the prevalence of CV in children. Larger studies are needed to define TCD ultrasonography–based CV criteria for children.
Metastatic renal cell carcinoma mimicking a schwannoma in a dorsal root ganglion: case report
Authors: Wasserman Jason K. , Tsai Eve C. , Glikstein Rafael , Mai Kien T. , Jansen Gerard H.
Published: January 2015

Peripheral nerve tumors are soft-tissue tumors that can occur in any nerve throughout the body. The majority of peripheral nerve tumors arise from elements of the nerve sheath with the two most common being neurofibromas and schwannomas. More than 90% of all peripheral nerve tumors are benign. When there is peripheral nerve involvement in metastatic carcinoma, it is often via contiguous spread from the primary mass; hematogenous seeding to a peripheral nerve is seldom seen. In this report the authors describe the even rarer case of metastatic renal cell carcinoma mimicking a schwannoma in a dorsal root ganglion. Cases from the literature show the rarity of this finding and its late clinical appearance. Given that survival in patients with metastatic carcinoma continues to increase, dorsal root ganglion metastasis may become more common over time.