bluuebunny/crossref_metadata_2025 huggingface dataset:
BIOLOGIA DA REPRODUÇÃO EM QUATRO ESPÉCIES DE Centrosema (DC.) BENTH
Authors: Battistin Alice , Lovatto Marlene Terezinha
Published: August 2014

RESUMO Com a finalidade de obter informações básicas sobre biologia floral das espécies: C. brasilianum (L.) Benth., C. Virginianum (L) Benth., C. shottii (Mill.) K. Sch. e C. pascuorum (Mart.) Benth., foram estudados comparativamente três parâmetros biológicos: número de óvulos por ovário, sementes por vagem que chegaram à maturidade e grãos de pólen viáveis. Os dados foram coletados no Campo Experimental do Instituto de Genética da ESALQ/USP - Piracicaba, SP e no Jardim Botânico do Departamento de Biologia da Universidade Federal de Santa Maria (UFSM) - Santa Maria, RS. As diferenças ocorridas nos parâmetros analisados mostram, de uma certa forma, a individualidade comportamental de cada espécie, decorrente de uma sensibilidade e variabilidade específicas. Todas as espécies estudadas tiveram uma produção de óvulos férteis acima de 78% e pólen viável acima de 95%. que refletiu uma elevada porcentagem de sementes viáveis (com exceção de C. shottii e C. pascuorum - Santa Maria, RS), garantindo desta forma a perpetuação da espécie.
VIABILIDADE DO EMPREGO DE UMA MINIDOSE DE PROSTAGLANDINA NA SINCRONIZAÇÃO DE CIOS EM OVINOS
Authors: Chagas Lúcia Martins , Souza Carlos José Hoff de , Moura Adilson , Moraes José Carlos Ferrugem
Published: August 2014

RESUMO São apresentados resultados de três experimentos seqüenciais que investigaram a viabilidade da redução da dosagem recomendada de prostaglandina para a sincronização de cios em ovinos via injeção na submucosa vulvar. Os resultados indicaram a possibilidade de utilização de uma terça parte da dose usual. Em sistemas de sincronização de nove dias os melhores resultados foram obtidos com a aplicação no sexto dia de serviço.
Influence of shear stress on cylindrical cavity expansion in undrained elastic–perfectly plastic soil
Authors: Zhou H. , Liu H. , Kong G.
Published: August 2014

The conventional cavity expansion method is based on the assumption of uniform radial pressure applied at the cavity wall boundary without considering the shear stress. However, in practice, shear stress may exist at the cavity wall, such as during the drilling process of drilled displacement piles. This note presents an analysis of the influence of shear stress on cylindrical cavity expansion in an undrained elastic–perfectly plastic soil. The problem is formulated by assuming large strain in the plastic zone and small strain in the elastic zone around the cavity, with a plane-strain condition under the cavity expansion process. Plastic yielding is determined by the Tresca failure criterion and an associated flow rule. A closed-form solution for the pressure–expansion relation is given to modify the conventional pressure–expansion relation without considering the influence of the shear stress. The plastic zone radius, cavity wall limit pressure, stress and excess pore pressure are also obtained. Furthermore, parametric studies are carried out to investigate the influence of shear stress on the cavity wall limit pressure, stress, excess pores pressure distributions around an expanding cylindrical cavity and the plastic zone radius. The results show that shear stress at the cavity wall boundary has a significant influence on the pressure–expansion relation and cannot be neglected when deriving the cavity wall pressure or excess pore pressure. However, the plastic zone radius is not sensitive to the shear stress. The present work provides a more general solution and improves the conventional cavity expansion theoretical framework.
The influence of membrane composition on the release of polyphenols from liposomes
Authors: Pravilovic Radoslava , Radunovic Vesna , Boskovic-Vragolovic Nevenka , Bugarski Branko , Pjanovic Rada
Published: September 2014

Polyphenols are compound which are widely studied because of their
antioxidative and potential therapeutic properties. Systems for the
controlled release of drugs offer a number of benefits comparing with
traditional forms of medicines and because of that these systems are widely
researched. The objective of this paper is to investigate the possibility of
using liposomes as carriers of polyphenols and influence the membrane
composition on the release rate of encapsulated polyphenols. Experiments show
how the membrane modification affects the mass transfer comparing to a
conventional liposomes. Liposomes were modified with surfactants Tween 20 and
Tween 60, and thyme tea extract was used as a source of polyphenols. The
diffusion of polyphenols from thyme extract, dispersion of conventional
liposomes and liposomes modified with Tween 20 and Tween 60 was studied using
Franz diffusion cell. From the experimental data diffusion coefficients were
determined for each of the systems, as well as the corresponding diffusion
resistances. From the obtained results it can be concluded that the
encapsulation of polyphenols in liposomes significantly slows diffusion, and
with membrane modification can be achieved further slowing. The diffusion
resistance of the liposome membrane modified with Tween 20 and Tween 60 is
about 5 times higher compared to the diffusion of unencapsulated polyphenols
from the thyme extract.
Influence of suturing material on wound healing: Experimental study in dogs
Authors: Gazivoda Dragan , Pelemis Dejan , Vujaskovic Goran , Djurdjevic Slavisa
Published: September 2014

Background/Aim. The most common materials implanted in the human organism are
suture materials that are classified on the basis of several criteria,
usually the origin, structure, and properties. The properties of suture
materials are related to its absorbability and non-absorbability. When using
resorbable materials it is of great importance to determine whether its
absorbability and tensile strength help wound healing in function of time.
Sutures themselves can become a source of inflammation, that may reduce or
compromise the potential of reparation and regeneration. The aim of this
experimental study on dogs was to ascertain whether the absorption rate and
the degree of local tissue reactions differ from information provided by the
manufacturers, whether there are differences between the applied suture
materials and which of the used suture materials have better effect on wound
healing. Methods. Experimental testing of the selected suture materials
basic characteristics was performed on 6 German Shepherd dogs, which, after
induction of general anesthesia, were made 3 identical incisions each in all
4 quadrants (left and right side of the upper and lower jaws), so that 12
horizontal incisions were formed, 10 mm long, 20-25 mm distant from one
another, on each animal. Randomly, incisions were stitched up in the
following order, starting from back to front: catgut, Dexon?, Vicryl-Rapid?.
The experiment was terminated by histopathological examination of tissue
samples, taken on postoperative day 3, 7, 14 and 21 in order to identify the
effect of healing and the degree of local reaction. Results. The obtained
results suggest that catgut has the highest absorption rate, while Dexon?
the lowest. Vicryl-Rapid? causes the lowest level of local reactions, while
Dexon? the highest. Conclusion. There is no ideal suture material because
various patient factors also influence the wound healing process.
Wave Propagation in a Micropolar Transversely Isotropic Generalized Thermoelastic Half-Space
Authors: Gupta R.R.
Published: September 2014

Rayleigh waves in a half-space exhibiting microplar transversely isotropic generalized thermoelastic properties based on the Lord-Shulman (L-S), Green and Lindsay (G-L) and Coupled thermoelasticty (C-T) theories are discussed. The phase velocity and attenuation coefficient in the previous three different theories have been obtained. A comparison is carried out of the phase velocity, attenuation coefficient and specific loss as calculated from the different theories of generalized thermoelasticity along with the comparison of anisotropy. The amplitudes of displacements, microrotation, stresses and temperature distribution were also obtained. The results obtained and the conclusions drawn are discussed numerically and illustrated graphically. Relevant results of previous investigations are deduced as special cases.
Theoretical Study of Heat Transfer Effects on Flow Past a Parabolic Started Vertical Plate in the Presence of Chemical Reaction of First Order
Authors: Muthucumaraswamy R. , Velmurugan S.
Published: September 2014

An exact solution of an unsteady flow past a parabolic starting motion of an infinite vertical plate with variable temperature and mass diffusion, in the presence of a homogeneous chemical reaction of first order has been studied. The plate temperature as well as concentration level near the plate are raised linearly with time t. The dimensionless governing equations are solved using the Laplace-transform technique. The effects of velocity profiles are studied for different physical parameters such as the chemical reaction parameter, thermal Grashof number, mass Grashof number, Schmidt number and time. It is observed that the velocity increases with increasing values of the thermal Grashof number or mass Grashof number. The trend is just reversed with respect to the chemical reaction parameter.
Experimental and Finite Element Studies on Free Vibration of Skew Plates
Authors: Srinivasa C.V. , Suresh Y.J. , Prema Kumar W.P.
Published: September 2014

The present paper deals with the experimental studies carried out on free vibration of isotropic and laminated composite skew plates. The natural frequencies were also determined using QUAD8 finite element of MSC/NASTRAN and a comparison was made between the experimental values and the finite element solution. The effects of the skew angle and aspect ratio on the natural frequencies of isotropic skew plates were studied. The effects of the skew angle, aspect ratio, fiber orientation angle and laminate sequence (keeping the number of layers constant) on the natural frequencies of antisymmetric composite laminates were also studied. The experimental values of natural frequencies are in good agreement with the FE solutions. The natural frequencies are found to increase with an increase in the skew angle. The variation of natural frequencies with the aspect ratio is small and negligible both for isotropic and laminated composite skew plates.
Effect of Periphery Fixity on Ballistic Limit of Thin Aluminum Plate Subjected to Blunt and Ogival Projectile Impact
Authors: Tiwari G. , Iqbal M.A. , Gupta P.K.
Published: September 2014

Three-dimensional numerical simulations were carried out with the ABAQUS/explicit finite element code to study the influence of target boundary conditions on its ballistic limit. 1mm thick 1100-H12 aluminum target of 255 mm span diameter was hit by 19 mm diameter and 50.8 mm length blunt nosed projectile. The mass of the projectile was kept as 52.5 gm. The boundary condition effects on the ballistic limit were investigated by varying the target periphery boundary condition as fully clamped and partially clamped target (75%, 50% and 25%) subjected to projectile impact. The energy absorption and ballistic limit of the target was found to be significantly affected by the boundary conditions. Some of the finite element analysis results were compared with experimental and numerical results reported in international literature and a good agreement between the two was found.
The Maximum Principle of Pontryagin in Control of Twolegged Robot Based on Human Walking System
Authors: Żur K.K.
Published: September 2014

In the paper a hypothesis about state equations of human gait is presented. Instantaneous normalized power developed by human muscles at particular joints of a leg is a control vector in state equations of the human walking system. The maximum principle of Pontryagin in analysis of dynamic human knee joint was presented. The discrete Hamilton function of a knee joint is similar to a discrete square function of normalized power developed by muscles at the knee joint. The results satisfy optimal conditions and could be applied in control of exoskeleton and DAR type robot.
We Can Do Better
Authors: Wilk Kevin E.
Published: September 2014

Typically, the goal of any rehabilitation program is to return the patient/athlete to the preinjury level. This is the frequently used benchmark reported in the literature when determining rehabilitation goals or describing the outcomes following anterior cruciate ligament injury or reconstruction. The first question we should ask ourselves is, “Is returning a patient to the preinjury level good enough?”

J Orthop Sports Phys Ther 2014;44(9):634–635. doi:10.2519/jospt.2014.0112
Incidence and Predictors of Contrast Induced Nephropathy after Coronary Intervention at College of Medical Sciences Teaching Hospital, Bharatpur
Authors: Sharma Sanjib Kumar , Dubey Laxman , Laudary Shankar , Dhungel Sachin , Ghimire Madhav , Pahari Bishnu , Gautam Samir , Guruprasad Sogunuru , Subramanyam Gangapatnam
Published: September 2014

Background and Aims: The implications of radio-contrast induced nephropathyare disastrous. In Nepal there is scarcity of data on contrast induced nephropathy. This observational descriptive study was undertaken to study the incidence of contrast induced nephropathy and to identify risk factors (predictors) for the development of contrast induced nephropathy in patients undergoing coronary angiography and angioplasty in atertiary care hospital. Methods: The subject consists of 540 patients undergoing coronary intervention from 2011 to 2013 were enrolled by convenient sampling technique. Two hundreds ten patients were excluded from the study. Therefore, a total of 330 patients were studied and analyzed. Contrast induced nephropathy was defined as an increase of >25% or >0.5 mg/dl in pre-catheterization serum creatinine at or after 48 h after percutaneous coronary intervention. Estimated glomerular filtration rate as calculated by applying the 4 variables Modification of Diet in Renal Disease Study equation. Standard definitions were used to define the variables. Results: Twenty seven (8.18%) patients experienced contrast induced nephropathy. The incidence of contrast induced nephropathy in patients with baseline creatinine clearance <60 ml/min was 45.9%. Contrast induced nephropathy developed in 10% of anemic and 12.5% diabetic patients. The amount of the contrast agent administered was similar for both groups of patients (138.20±91.34ml vs. 175.56±118.86ml; p =0.254). No correlation was found between the amount of contrast agent administered and the change of serum creatinine concentration. Multivariate logistic regression analysis found that baseline e-GFR and baseline hemoglobin were independent predictors for Contrast induced nephropathy. Conclusion: The overall incidence of Contrast induced nephropathy after coronary intervention in this study is high. Patients with both preexisting renal insufficiency and anemia were at high risk of Contrast induced nephropathy. DOI: http://dx.doi.org/10.3126/njh.v11i1.10975 Nepalese Heart Journal 2014;11(1): 3-11
Echocardiographic Profile of Patients in Dhulikhel Hospital, A Medical College Hospital in Nepal
Authors: Humagain Sanjaya , Twayana Ramsundar , Koju Rajendra
Published: September 2014

Background and Aim : Echocardiograph is an important diagnostic tool to evaluate cardiac disease and is indispensible for management. So it is important to know the spectrum of cardiac abnormalities that can be detected by echocardiograph and the frequency of these findings may vary depending on where the echocardiogram is performed. Aim of this study was to find out the spectrum of echocardiographic finding in different age group in a medical college hospital. Methods and materials : A retrospective observational study was done to at Dhulikhel Hospital to review Echocardiographic profile of 3310 patients who were indicated for echocardiogram over a period of 3 years. Data collected from echocardiograph report registry. Data analysis was done using SPSS 17. Result : Congenital Heart Disease(CHD) (37.74%),Normal finding( 21.19%), Pericardial Heart Disease(19.21%) and Rheumatic Heart Disease(RHD)(17.88%) were the echocardiographic finding in children. In adolescents and young adults Rheumatic Heart Disease (49.90%), Hypertensive Heart Disease (13.34%), Congenital Heart Disease (6.58%), and Pericardial Disease (4.38%) were found. Most common finding in middle age was cor-pulmonale (34.76%) followed by Diastolic Dysfunction (20.60%), Hypertensive Heart Disease(17.06%),Ischemic Heart Disease(IHD) (12.80%). In elderly age most common finding was Diastolic Dysfunction (57.14%). Conclusion : The spectrum of echocardiograph finding in a medical college hospital ranges from Congenital Heart Disease, Rheumatic Heart Disease, Ischemic Heart Disease ,Pericardial disease, Corpulmonale, Diastolic Dysfunction, systolic dysfunction and degenerative valve disease. Streptococcal sore throat leading to Rheumatic Heart Disease and complication of tuberculosis and parasitic infestation leading to pericardial diseases, as well as Hypertensive Heart Disease, and Ischemic Heart Disease constitutes burden in Nepal. Cor-pulmonale and ) Sanjaya Humagain, Ramsundar Twayana, Rajendra Koju. DOI: http://dx.doi.org/10.3126/njh.v11i1.10976   Nepalese Heart Journal 2014;11(1): 13-17
Echocardiographic Evaluation of Diastolic Dysfunction in Patients with Subclinical Hypothyroidism & the effect of L-Thyroxine treatment: A hospital based study
Authors: Karki Prahlad , Pandey Ila , Bhandary Sangita , Lamsal Madhab , Shrestha Nikesh Raj
Published: September 2014

Background & Aims: Diastolic dysfunction is the common condition with Subclinical Hypothyroidism and is reversible in many cases after treatment. We aimed to investigate the response of diastolic dysfunction to thyroid hormone replacement therapy in patients of Subclinical Hypothyroidism. Methods: Forty newly diagnosed cases of Subclinical Hypothyroidism (38 females and 2 males) and age more than 18 years were included. Diagnosis was made on the basis of history, clinical examination and thyroid function tests. Echocardiography was performed in all and was repeated after 4-6 months in those who had diastolic dysfunction. Distribution of Diastolic dysfunction among the involved cases and their response to treatment with L-thyroxine were studied. Results: The diastolic dysfunction was found in 15 (37.5%) and pericardial effusion (PE) in five (12.5%) patients. Fourteen of them had impaired relaxation abnormality and only one patient had pseudonormal pattern. With replacement therapy, 13 reverted back to the normal whereas one having grade 2 diastolic dysfunction (pseudonormal pattern) reverted to grade 1. One patient who had grade 1 diastolic dysfunction (impaired relaxation) did not improve. Pericardial effusion subsided in all 5 cases. Conclusions: Echocardiography may be a useful tool for monitoring the response of diastolic dysfunction to thyroid hormone replacement therapy in patients with Subclinical Hypothyroidism. Our findings suggest that Thyroid Hormone Replacement Therapy may reverse diastolic dysfunction in Subclinical Hypothyroidism. DOI: http://dx.doi.org/10.3126/njh.v11i1.10979   Nepalese Heart Journal 2014;11(1): 33-38
Initial experience with extracorporeal membrane oxygenation following cardiac surgery in children with congenital heart disease
Authors: Sharma Apurb , Pokharel Jeju Nath , Upreti Murari Raj , Koirala Bhagawan , Sharma Jyotindra , Pradhan Siddartha , Bhatta Mahendra
Published: September 2014

Background and Aim: Cardiac extra-corporeal membrane oxygenation is a mechanical life support system initiated in patients with extreme cardiopulmonary failure. Extracorporeal circulation after cardiac surgery supports the heart and lungs recover from the acute injuries of the surgery. Aims of this study were to present our initial experience about complications and outcome with the use of extracorporeal membrane oxygenation following open-heart surgery for congenital cardiac anomalies. Methods: Medical records of all pediatric and neonatal patients requiring extracorporeal life support following cardiac surgery for congenital cardiac anomalies were retrospectively reviewed. Patient and extracorporeal system characteristics were evaluated. Results: Between 2009 and 2012, eight children were treated at our institution with mechanical extracorporeal life support system following open heart surgery. Median age was four months and mean weight was 7.24 kilograms. The indications for initiation of extracorporeal support were difficulty in weaning off cardiopulmonary bypass despite maximal inotropic support, refractory pulmonary oedema immediately after cardiopulmonary bypass and right ventricular dysfunction in postoperative period. Two patients were weaned from the extracorporeal support successfully. Conclusions: Initial results of our extra-corporeal membrane oxygenation programme do not meet the international standards. It can still be a valuable strategy for saving lives after paediatric cardiac surgery. DOI: http://dx.doi.org/10.3126/njh.v11i1.10980   Nepalese Heart Journal 2014;11(1): 39-44
Medical Management of ST elevation Myocardial infarction - Where are we?
Authors: Adhikari Chandra Mani , Rajbhandari Sujeeb , Prajapati Dipanker , Shrestha Nagma , Baniya Bibeka , Bogati Amrit , Gurung Prakash , Thapaliya Suman
Published: September 2014

Background and Aims: Despite well developed guidelines in the management of ST elevation myocardial infarction, registries worldwide have demonstrated incomplete implementation of evidence-based recommendations. Our study aims to assess the adherence of our practices to the recommended clinical guidelines, which is based on the discharge prescription in Shahid Gangalal National Heart Centre. Methods: Medical records of 495 ST elevation myocardial infarction patients discharged from our centre in between January 2012 to December 2012 were retrospectively reviewed. Results: Among the 495 patients included in this study, 372 (75.1%) were males and 123 (24.9%) were females. The mean age was 56.9±12.4 years. Aspirin, Clopidrogel and statin were prescribed in more than 95% of the patients. Angiotensin Converting Enzyme inhibitor/ Angiotensin Receptor blockers was prescribed more often than β-blockers. Only a small numbers of patients were discharged without Angiotensin Converting Enzyme inhibitor /Angiotensin Receptor Blockers or β-blockers. Conclusions: Usage of Aspirin, clopidogrel, statins, beta blockers and Angiotensin Converting Enzyme inhibitor/ Angiotensin Receptor Blockers s is comparable to international studies. We still need some effort to increase improve our prescription rate of β-blockers and Angiotensin Converting Enzyme inhibitor/ Angiotensin Receptor Blockers. DOI: http://dx.doi.org/10.3126/njh.v11i1.10981 Nepalese Heart Journal 2014;11(1): 45-48
Management of intracranial aneurysms associated with arteriovenous malformations
Authors: Flores Bruno C. , Klinger Daniel R. , Rickert Kim l. , Barnett Samuel l. , Welch Babu G. , White Jonathan A. , Batjer H. Hunt , Samson Duke S.
Published: September 2014

Intracranial or brain arteriovenous malformations (BAVMs) are some of the most interesting and challenging lesions treated by the cerebrovascular neurosurgeon. It is generally believed that the combination of BAVMs and intracranial aneurysms (IAs) is associated with higher hemorrhage rates at presentation and higher rehemorrhage rates and thus with a more aggressive course and natural history. There is wide variation in the literature on the prevalence of BAVM-associated aneurysms (range 2.7%–58%), with 10%–20% being most often cited in the largest case series. The risk of intracranial hemorrhage in patients with unruptured BAVMs and coexisting IAs has been reported to be 7% annually, compared with 2%–4% annually for those with BAVM alone. Several different classification systems have been applied in an attempt to better understand the natural history of this combination of lesions and implications for treatment. Independent of the classification used, it is clear that a few subtypes of aneurysms have a direct hemodynamic correlation with the BAVM itself. This is exemplified by the fact that the presence of a distal flow-related or an intranidal aneurysm appears to be associated with an increased hemorrhage risk, when compared with an aneurysm located on a vessel with no direct supply to the BAVM nidus. Debate still exists regarding the etiology of the association between those two vascular lesions, the subsequent implications for patients’ risk of hemorrhagic stroke, and finally the determination of which patients warrant treatment and when. The ultimate goals of the treatment of a BAVM associated with an IA are to prevent hemorrhage, avoid stepwise neurological deterioration, and eliminate the mortality risk associated with recurrent hemorrhagic events. The treatment is only justifiable if the risks associated with an intervention are lower than or equivalent to the long-term risks of disability or mortality caused by the lesion itself. When faced with this difficult decision, a few questions need to be answered by the treating neu-rosurgeon: What is the mode of presentation? What is the symptomatic lesion? Which one of the lesions bled? What is the relationship between the BAVM and IA? Is it possible to safely treat both BAVM and IA? The objective of this review is to discuss the demographics, natural history, classification, and strategies for management of BAVMs associated with IAs.
Staged-volume radiosurgery for large arteriovenous malformations: a review
Authors: AlKhalili Kenan , Chalouhi Nohra , Tjoumakaris Stavropoula , Rosenwasser Robert , Jabbour Pascal
Published: September 2014

Stereotactic radiosurgery is an effective management strategy for properly selected patients with arteriovenous malformations (AVMs). However, the risk of postradiosurgical radiation-related injury is higher in patients with large AVMs. Multistaged volumetric management of large AVMs was undertaken to limit the radiation exposure to the surrounding normal brain. This strategy offers a promising method for obtaining high AVM obliteration rates with minimal normal tissue damage. The use of embolization as an adjunctive method in the treatment of large AVMs remains controversial. Unfortunately, staged-volume radiosurgery (SVR) has a number of potential pitfalls that affect the outcome. The aim of this article is to highlight the role of SVR in the treatment of large AVMs, to discuss the outcome comparing it to other treatment modalities, and to discuss the potential improvement that could be introduced to this method of treatment.
Association between posterior fossa arteriovenous malformations and prenidal aneurysm rupture: potential impact on management
Authors: Kouznetsov Evgueni , Weill Alain , Ghostine Jimmy S. , Gentric Jean-Christophe , Raymond Jean , Roy Daniel
Published: September 2014

Object

In patients with posterior fossa arteriovenous malformations (AVMs) who present with hemorrhage, feeding artery aneurysms are often the source of bleeding. The aim of this study was to evaluate the relative proportions of cases of infra- and supratentorial AVMs in which patients presented with prenidal aneurysm rupture. The management and outcome of 9 cases of posterior fossa AVMs associated with prenidal aneurysm rupture are presented.

Methods

The authors retrospectively reviewed 233 consecutive AVM cases involving patients treated at their institution between April 2001 and August 2012. Patients with a prenidal aneurysm as the cause of the hemorrhage were identified. The frequencies of prenidal aneurysm-related ruptures were compared in cases of supra- and infratentorial AVMs. Management and clinical outcome (modified Rankin Scale [mRS] score) of patients with posterior fossa AVMs treated for ruptured prenidal aneurysms were recorded.

Results

Of 233 AVMs, 25 (11%) were in the posterior fossa, and in 22 (88%) of these cases, the patients presented with hemorrhage, including 9 patients (41%) who presented with hemorrhage due to prenidal aneurysm rupture. Of 208 patients with supratentorial AVMs, 107 (51%) presented with hemorrhage, including 5 patients (4.7%) in whom the hemorrhage was associated with a prenidal aneurysm (p < 0.01). All 9 patients with posterior fossa AVMs and prenidal aneurysm rupture were treated with early embolization of the offending aneurysm. There was no early rebleeding or clinical complication related to this approach. At the end of follow-up (mean 46.8 months), 2 patients had an mRS score of 0, 1 had a score of 1, 3 had a score of 2, 2 patients were dead (mRS score of 6), and 1 patient was lost to follow-up.

Conclusions

Posterior fossa AVM hemorrhages are frequently associated with prenidal arterial aneurysms. Urgent endovascular treatment of the aneurysm was effective in this case series.
Are parenchymal AVMs congenital lesions?
Authors: Morales-Valero Saul F. , Bortolotti Carlo , Sturiale Carmelo , Lanzino Giuseppe
Published: September 2014

A long-held dogma in neurosurgery is that parenchymal arteriovenous malformations (AVMs) are congenital. However, there is no strong evidence supporting this theory. An increasing number of documented cases of de novo formation of parenchymal AVMs cast doubt on their congenital nature and suggest that indeed the majority of these lesions may form after birth. Further evidence suggesting the postnatal development of parenchymal AVMs comes from the exceedingly rare diagnosis of these lesions in utero despite the widespread availability of high-resolution imaging modalities such as ultrasound and fetal MRI. The exact mechanism of AVM formation has yet to be elucidated, but most likely involves genetic susceptibility and environmental triggering factors. In this review, the authors report 2 cases of de novo AVM formation and analyze the evidence suggesting that they represent an acquired condition.
Natural history of brain arteriovenous malformations: a systematic review
Authors: Abecassis Isaac Josh , Xu David S. , Batjer H. Hunt , Bendok Bernard R.
Published: September 2014

Object

The authors aimed to systematically review the literature to clarify the natural history of brain arteriovenous malformations (BAVMs).

Methods

The authors searched PubMed for one or more of the following terms: natural history, brain arteriovenous malformations, cerebral arteriovenous malformations, and risk of rupture. They included studies that reported annual rates of hemorrhage and that included either 100 patients or 5 years of treatment-free follow-up.

Results

The incidence of BAVMs is 1.12–1.42 cases per 100,000 person-years; 38%–68% of new cases are first-ever hemorrhage. The overall annual rates of hemorrhage for patients with untreated BAVMs range from 2.10% to 4.12%. Consistently implicated in subsequent hemorrhage are initial hemorrhagic presentation, exclusively deep venous drainage, and deep and infrantentorial brain location. The risk for rupture seems to be increased by large nidus size and concurrent arterial aneurysms, although these factors have not been studied as thoroughly. Venous stenosis has not been implicated in increased risk for rupture.

Conclusions

For patients with BAVMs, although the overall risk for hemorrhage seems to be 2.10%–4.12% per year, calculating an accurate risk profile for decision making involves clinical attention and accounting for specific features of the malformation.
Seizure outcomes following radiosurgery for cerebral arteriovenous malformations
Authors: Chen Ching-Jen , Chivukula Srinivas , Ding Dale , Starke Robert M. , Lee Cheng-Chia , Yen Chun-Po , Xu Zhiyuan , Sheehan Jason P.
Published: September 2014

Object

Seizures are a common presentation of cerebral arteriovenous malformations (AVMs). The authors evaluated the efficacy of stereotactic radiosurgery (SRS) for the management of seizures associated with AVMs and identified factors influencing seizure outcomes following SRS for AVMs.

Methods

A systematic literature review was performed using PubMed. Studies selected for review were published in English, included at least 5 patients with both cerebral AVMs and presenting seizures treated with SRS, and provided post-SRS outcome data regarding obliteration of AVMs and/or seizures. Demographic, radiosurgical, radiological, and seizure outcome data were extracted and analyzed. All seizure outcomes were categorized as follows: 1) seizure free, 2) seizure improvement, 3) seizure unchanged, and 4) seizure worsened. Systematic statistical analysis was conducted to assess the effect of post-SRS AVM obliteration on seizure outcome.

Results

Nineteen case series with a total of 3971 AVM patients were included for analysis. Of these, 28% of patients presented with seizures, and data for 997 patients with available seizure outcome data who met the inclusion criteria were evaluated. Of these, 437 (43.8%) patients achieved seizure-free status after SRS, and 530 (68.7%) of 771 patients with available data achieved seizure control (seizure freedom or seizure improvement) following SRS. Factors associated with improved seizure outcomes following SRS for AVMs were analyzed in 9 studies. Seizure-free status was achieved in 82% and 41.0% of patients with complete and incomplete AVM obliteration, respectively. Complete AVM obliteration offered superior seizure-free rates compared with incomplete AVM obliteration (OR 6.13; 95% CI 2.16–17.44; p = 0.0007).

Conclusions

Stereotactic radiosurgery offers favorable seizure outcomes for AVM patients presenting with seizures. Improved seizure control is significantly more likely with complete AVM obliteration.
Molecular and cellular biology of cerebral arteriovenous malformations: a review of current concepts and future trends in treatment
Authors: Rangel-Castilla Leonardo , Russin Jonathan J. , Martinez-del-Campo Eduardo , Soriano-Baron Hector , Spetzler Robert F. , Nakaji Peter
Published: September 2014

Object

Arteriovenous malformations (AVMs) are classically described as congenital static lesions. However, in addition to rupturing, AVMs can undergo growth, remodeling, and regression. These phenomena are directly related to cellular, molecular, and physiological processes. Understanding these relationships is essential to direct future diagnostic and therapeutic strategies. The authors performed a search of the contemporary literature to review current information regarding the molecular and cellular biology of AVMs and how this biology will impact their potential future management.

Methods

A PubMed search was performed using the key words “genetic,” “molecular,” “brain,” “cerebral,” “arteriovenous,” “malformation,” “rupture,” “management,” “embolization,” and “radiosurgery.” Only English-language papers were considered. The reference lists of all papers selected for full-text assessment were reviewed.

Results

Current concepts in genetic polymorphisms, growth factors, angiopoietins, apoptosis, endothelial cells, pathophysiology, clinical syndromes, medical treatment (including tetracycline and microRNA-18a), radiation therapy, endovascular embolization, and surgical treatment as they apply to AVMs are discussed.

Conclusions

Understanding the complex cellular biology, physiology, hemodynamics, and flow-related phenomena of AVMs is critical for defining and predicting their behavior, developing novel drug treatments, and improving endovascular and surgical therapies.
Contemporary management of spinal AVFs and AVMs: lessons learned from 110 cases
Authors: Rangel-Castilla Leonardo , Russin Jonathan J. , Zaidi Hasan A. , Martinez-del-Campo Eduardo , Park Min S. , Albuquerque Felipe C. , McDougall Cameron G. , Nakaji Peter , Spetzler Robert F.
Published: September 2014

Object

Spinal arteriovenous fistulas (AVFs) and arteriovenous malformations (AVMs) are rare, complex spinal vascular lesions that are challenging to manage. Recently, understanding of these lesions has increased thanks to neuroimaging technology. Published reports of surgical results and clinical outcome are limited to small series. The authors present a large contemporary series of patients with spinal AVFs and AVMs who were treated at Barrow Neurological Institute in Phoenix, Arizona.

Methods

Retrospective detailed review of a prospective vascular database was performed for all patients with spinal AVFs and AVMs treated between 2000 and 2013. Patient demographic data, AVF and AVM characteristics, surgical results, clinical outcomes, complications, and long-term follow-up were reviewed.

Results

Between 2000 and 2013, 110 patients (57 male and 53 female) underwent obliteration of spinal AVFs and AVMs. The mean age at presentation was 42.3 years (range 18 months–81 years). There were 44 patients with AVFs and 66 with AVMs. The AVM group included 27 intramedullary, 21 conus medullaris, 12 metameric, and 6 extradural. The most common location was thoracic spine (61%), followed by cervical (22.7%), lumbar (14.5%), and sacral (1.8%). The most common presenting signs and symptoms included paresis/paralysis (75.5%), paresthesias (60%), pain (51.8%), bowel/bladder dysfunction (41.8%), and myelopathy (36.4%). Evidence of rupture was seen in 26.4% of patients. Perioperative embolization was performed in 42% of patients. Resection was performed in 95 patients (86.4%). Embolization alone was the only treatment in 14 patients (12.7%). One patient was treated with radiosurgery alone. Angiographically verified AVF and AVM obliteration was achieved in 92 patients (83.6%). At a mean follow-up duration of 30.5 months (range 1–205 months), 43 patients (97.7%) with AVFs and 57 (86.4%) with AVMs remained functionally independent (McCormick Scale scores ≤ 2). Perioperative complications were seen in 8 patients (7%). No deaths occurred. Temporary neurological deficits were observed in 27 patients (24.5%). These temporary deficits recovered 6–8 weeks after treatment. Recurrence was identified in 6 patients (13.6%) with AVFs and 10 (15.2%) with AVMs.

Conclusions

Spinal AVFs and AVMs are complex lesions that should be considered for surgical obliteration. Over the last several decades the authors have changed surgical strategies and management to achieve better clinical outcomes. Transient neurological deficit postoperatively is a risk associated with intervention; however, clinical outcomes appear to exceed the natural history based on patients’ ability to recover during the follow-up period. Due to the recurrence rate associated with these lesions, long-term follow-up is required.
Thoracic arachnoid cyst resection
Authors: Deutsch Harel
Published: September 2014

Arachnoid cysts in the spinal cord may be asymptomatic. In some cases arachnoid cysts may exert mass effect on the thoracic spinal cord and lead to pain and myelopathy symptoms. Arachnoid cysts may be difficult to visualize on an MRI scan because the thin walled arachnoid may not be visible. Focal displacement of the thoracic spinal cord and effacement of the spinal cord with apparent widening of the cerebrospinal fluid space is seen. This video demonstrates surgical techniques to remove a dorsal arachnoid cyst causing spinal cord compression. The surgery involves a thoracic laminectomy. The dura is opened sharply with care taken not to open the arachnoid so that the cyst can be well visualized. The thickened arachnoid walls of the cyst are removed to alleviate the compression caused by the arachnoid cyst.

The video can be found here: http://youtu.be/pgUrl9xvsD0.
Release and repair of a ventral thoracic spinal cord herniation
Authors: McCormick Paul C.
Published: September 2014

Ventral thoracic spinal cord herniation is a rare but increasingly recognized cause of progressive myelopathy. This video demonstrates the imaging characteristics and surgical techniques for release and reduction of the spinal cord herniation as well as primary repair and reinforcement of the ventral dural hernia defect through an extended posterior approach. An instrumented fusion was concomitantly performed.

The video can be found here: http://youtu.be/6Pcokep6Tug.
Dorsal arachnoid web
Authors: McCormick Paul C.
Published: September 2014

Dorsal thoracic arachnoid web is a rare but often overlooked cause of progressive myelopathy. Syringomyelia, either above or below the compressive arachnoid band, may also be present. Dorsal arachnoid cyst and ventral spinal cord herniation may be mistaken for this condition. This video demonstrates the microsurgical identification and techniques of resection of a dorsal arachnoid band producing a progressive myelopathy in a 63-year-old man.

The video can be found here: http://youtu.be/KDNTqiyW6yo.
Microsurgical resection of intramedullary spinal cord hemangioblastoma
Authors: McCormick Paul C.
Published: September 2014

Spinal cord hemangioblastomas account for about 10% of spinal cord tumors. They usually arise from the dorsolateral pia mater and are characterized by their significant vascularity. The principles and techniques of safe resection are different than those employed for the more commonly occurring intramedullary glial tumors (e.g. ependymoma, astrocytoma) and consist of circumferential detachment of the tumor margin from the surrounding normal pia. This video demonstrates the microsurgical techniques of resection of a thoracic spinal cord hemangioblastoma.

The video can be found here: http://youtu.be/yT5KLi4VyAo.
Microsurgical ligation of spinal arteriovenous fistulae: techniques
Authors: Tuchek Chad A. , Cohen-Gadol Aaron A.
Published: September 2014

Spinal dural arteriovenous fistula (dAVF) is an acquired abnormal arterial-to-venous connection within the spinal dura with a wide range of clinical presentations and natural history. Spinal dAVF occurs when a radicular artery makes a direct anomalous shunt with a radicular vein within the dura of the nerve root sleeve. Spinal dAVFs are the most common vascular malformation of the spine.

The authors present a patient who presented with sudden temporary lower extremity weakness secondary to an L-1 spinal dAVF. The details of microsurgical techniques to disconnect the fistula are discussed in this video.

The video can be found here: http://youtu.be/F9Kiffs3s6A.
Resection of cervical ependymoma
Authors: Lanzino Giuseppe , Morales-Valero Saul F. , Krauss William E. , Campero Mario , Marsh W. Richard
Published: September 2014

Intramedullary ependymomas are surgically curable tumors. However, their surgical resection poses several challenges. In this intraoperative video we illustrate the main steps for the surgical resection of a cervical intramedullary ependymoma. These critical steps include: adequate exposure of the entire length of the tumor; use of the intraoperative ultrasound; identification of the posterior median sulcus and separation of the posterior columns; Identification of the plane between the spinal cord and the tumor; mobilization and debulking of the tumor and disconnection of the vascular supply (usually from small anterior spinal artery branches). Following these basic steps a complete resection can be safely achieved in many cases.

The video can be found here: http://youtu.be/QMYXC_F4O4U.
Introduction: Intradural Spinal Surgery video supplement
Authors: McCormick Paul C.
Published: September 2014

This Neurosurgical Focus video supplement contains detailed narrated videos of a broad range of intradural pathology such as neoplasms, including intramedullary, extramedullary, and dumbbell tumors, vascular malformations, functional disorders, and rare conditions that are often overlooked or misdiagnosed such as arachnoid cysts, ventral spinal cord herniation, and dorsal arachnoid web.

The intent of this supplement is to provide meaningful educational and instructional content at all levels of training and practice. As such, the selected video submissions each provide a comprehensive detailed narrative description and coordinated video that contains the entire spectrum of relevant information including imaging, operative setup and positioning, and exposure, as well as surgical strategies, techniques, and sequencing toward the safe and effective achievement of the operative objective. This level of detail often necessitated a more lengthy video duration than is typically presented in oral presentations or standard video clips from peer reviewed publications. Unfortunately, space limitations precluded the inclusion of several other excellent video submissions in this supplement.

While most videos in this supplement reflect standard operative approaches and techniques there are also submissions that describe innovative exposures and techniques that have expanded surgical options such as ventral approaches, stereotactic guidance, and minimally invasive exposures. There is some redundancy in both the topics and techniques both to underscore fundamental surgical principles as well as to provide complementary perspective from different surgeons.

It has been my privilege to serve as guest editor for this video supplement and I would like to extend my appreciation to Mark Bilsky, Bill Krauss, and Sander Connolly for reviewing the large number submitted videos. Most of all, I would like to thank the authors for their skill and effort in the preparation of the outstanding videos that constitute this video supplement.
Smoking is a negative predictor of arteriovenous malformation posttreatment obliteration: analysis of vascular risk factors in 774 patients
Authors: Dalyai Richard , Starke Robert M. , Chalouhi Nohra , Theofanis Thana , Busack Christopher , Jabbour Pascal , Gonzalez L. Fernando , Rosenwasser Robert , Tjoumakaris Stavropoula
Published: September 2014

Object

Cigarette smoking has been well established as a risk factor in vascular pathology, such as cerebral aneurysms. However, tobacco’s implications for patients with cerebral arteriovenous malformations (AVMs) are controversial. The object of this study was to identify predictors of AVM obliteration and risk factors for complications.

Methods

The authors conducted a retrospective analysis of a prospectively maintained database for all patients with AVMs treated using surgical excision, staged endovascular embolization (with N-butyl-cyanoacrylate or Onyx), stereotactic radiosurgery (Gamma Knife or Linear Accelerator), or a combination thereof between 1994 and 2010. Medical risk factors, such as smoking, abuse of alcohol or intravenous recreational drugs, hypercholesterolemia, diabetes mellitus, hypertension, and coronary artery disease, were documented. A multivariate logistic regression analysis was conducted to detect predictors of periprocedural complications, obliteration, and posttreatment hemorrhage.

Results

Of 774 patients treated at a single tertiary care cerebrovascular center, 35% initially presented with symptomatic hemorrhage and 57.6% achieved complete obliteration according to digital subtraction angiography (DSA) or MRI. In a multivariate analysis a negative smoking history (OR 1.9, p = 0.006) was a strong independent predictor of AVM obliteration. Of the patients with obliterated AVMs, 31.9% were smokers, whereas 45% were not (p = 0.05). Multivariate analysis of obliteration, after controlling for AVM size and location (eloquent vs noneloquent tissue), revealed that nonsmokers were more likely (0.082) to have obliterated AVMs through radiosurgery. Smoking was not predictive of treatment complications or posttreatment hemorrhage. Abuse of alcohol or intravenous recreational drugs, hypercholesterolemia, diabetes mellitus, and coronary artery disease had no discernible effect on AVM obliteration, periprocedural complications, or posttreatment hemorrhage.

Conclusions

Cerebral AVM patients with a history of smoking are significantly less likely than those without a smoking history to have complete AVM obliteration on follow-up DSA or MRI. Therefore, patients with AVMs should be strongly advised to quit smoking.