bluuebunny/crossref_metadata_2025 huggingface dataset:
Techbits: SPE/SEG Workshop on Injection-Induced Seismicity
Authors: JPT staff _
Published: February 2015

Techbits

In September, SPE and the Society of Exploration Geophysicists (SEG) cohosted a workshop on injection-induced seismicity in Broomfield, Colorado. The goal of the workshop was to determine industry knowledge about seismicity accompanying injection activities, identify the gaps in knowledge, and to discuss ways to improve understanding of such seismicity. Approximately 115 participants gathered to share knowledge from diverse regions and experiences. Attendees were evenly split between service companies and research organizations, and while a majority of the participants described themselves as geophysicists, about 20% were engineers. Encouraging an open discussion between engineers and geophysicists was one of the reasons for holding the workshop.

The opening session set the stage for the workshop, and included presentations about case studies of induced seismicity associated with several types of human activities. The benefits and risks of induced seismicity to subsurface and surface facilities were discussed as a basis for understanding what information is needed to better understand and mitigate potential risks associated with the seismicity.

A poster session (chaired by Jamie Rich) highlighted topics related to characterizing and mitigating fluid-induced seismicity. Other sessions included:

Underground Mines–In Situ Laboratories for Injection-Induced Seismicity (cochaired by Mark Willis).

This session focused on investigations into the established field of mining-induced seismicity, including case studies from fluid injections in underground mines and the opportunity to perform controlled studies.  

Induced Seismicity Associated with Enhanced Geothermal Systems (EGS)—From Understanding to Hazard Control (chaired by Serge Shapiro and Ahmed Abou-Sayed).

This session included discussions about seismicity accompanying the development of EGS reservoirs and how public and regulatory concerns about induced seismicity risk have been addressed particularly through the United States Department of Energy EGS-induced seismicity protocol.

Looking Back at Induced Seismicity—Case Histories Examining Wastewater Disposal and Induced Seismicity—What is Known (chaired by Julie Shemeta and Dicky Hall).

This session consisted of presentations about wastewater disposal operations, observations of the comparison of seismicity with various injections, and potential interaction with existing faults.

What Do We Know About Fraccing-Induced Seismicity (co-chaired by Jamie Rich). 

This included presentations about characterizing hydraulic fractures through microseismicity, the types of measurements that are made to characterize induced seismicity, and applications of those measurements. Statistical analysis methods for investigating the attribution of induced seismicity were discussed.
Coiled Tubing Advances Improve Extended Reach Drilling Operations
Authors: Dunnahoe Tayvis
Published: February 2015

Coiled Tubing

Fast setup and depth specific capabilities make coiled tubing (CT) the fastest growing technology in the oilfield services sector. Small diameter tubing spooled on a reel make for easy transportation, especially in remote areas. The main driver for CT usage stems from its ability to operate without a rig, which reduces an operator’s time and cost extensively. Because of its flexibility, the use of CT in horizontal and extended reach drilling operations has increased dramatically over the past few years.

While CT can achieve efficient results at lower costs in less time, it is not a perfect solution. Small tubing size increases the chances of lockup during intervention.  CT also suffers from a reduction in stiffness. In horizontal and highly deviated wells, tubing is exposed to high frictional forces as it is dragged against the wellbore and this can lead to buckling.

The extended reach capabilities of CT have been extended by several methods including tractor technology and rollers, which add force at the end of the tubing, pulling it deeper into the hole. Designed in the planning phase, tapered strings can improve the efficiency of an operation, but may limit its use in subsequent intervention projects. Improved friction reduction is one of the key features to ensure against early lockup. Whether done chemically, lubricating the drillstring and the wellbore, or through buoyancy reduction, new technology is achieving results in extended reach CT applications.

Horizontal Application

The Bakken play in North America covers a 200,000 square mile region from Montana and North Dakota in the United States to southern Saskatchewan in Canada. Second only to Texas in oil production, the play has an estimated ultimate recovery of 24 billion bbl of oil, according to Continental Resources. The company has been active in the North Dakota Bakken since it completed the first commercially successful horizontal well, the Robert Heuer 1-17R, in March 2004.

Since 2008, Continental and Sanjel have successfully performed more than 200 CT mill outs in the Bakken with more than 3,000 plugs milled. Traditionally, completion technology has drastically increased the number of fracture stages per well. Early this year, a Bakken record was set of 39 plugs in a single trip while reaching out to 10,024 ft in a lateral. Mill outs in the Bakken routinely reach more than 19,000 ft using downhole water hammer tools (WHT) and different CT string designs. As CT depths approach 20,000 ft, friction reducers are among several other technologies being sought by operators in the region.
Fluid- and Rock-Property Effects on Reserves Estimation
Authors: Denney Dennis
Published: February 2015

This article, written by Senior Technology Editor Dennis Denney, contains highlights of paper SPE 148717, ’Effects of Fluid and Rock Properties on Reserves Estimation,’ by Kegang Ling, SPE, Zheng Shen, SPE, Texas A&M University, prepared for the 2011 SPE Eastern Regional Meeting, Columbus, Ohio, 17-19 August. The paper has not been peer reviewed.

Precise reserves calculation is fundamental for production forecasting. Great efforts are made to obtain fluid and rock properties such as porosity, permeability, saturation, rock and fluid compressibility, viscosity, fluid gravity, gas z-factor, saturation pressure, reservoir pressure, and temperature. There is always uncertainty regarding the information because of instrument sensitivity and limitations, measurement error, environmental effects, sample interval, location, and how representative of the rock the sample is. A systematic study on the effects of fluid and rock properties on reserves estimation was conducted.

Introduction

Fluid and rock properties control the volume of original hydrocarbon in place and the recoverable oil and gas. Uncertainty and error exist because of the instrument sensitivity and limitations, measurement error, environmental effects, sample interval, location, and how representative of the rock the sample is. Measuring rock properties under reservoir conditions is very difficult. A synthetic field was built to study the effects of fluid and rock properties. It is an oil field with aquifer support. The initial reservoir pressure is above the bubblepoint pressure.

Initially, five producers were drilled to produce oil. With time, reservoir pressure declined. As the reservoir pressure declined below the bubblepoint with production, solution gas was released from oil. When the gas saturation reached critical saturation, it began to flow with the oil and water. This three-phase flow in the reservoir represents the middle and late production periods.

Model Description

The simulation model divides the reservoir into 93×93×2 gridblocks. The reservoir is modified to an irregular shape by assigning zero porosity and permeability to gridblocks at the reservoir edge. To populate the rock properties, different porosities, permeabilities, depths, and pay thicknesses were assigned to each gridblock. Initially, a uniform oil/water contact divided the porous sand into oil and water zones. Pressure at datum was assigned such that pressure above and below the datum can be calculated according to in-situ fluid density. Initial water saturation was assigned to respect the real oil reservoir. Rock and water compressibilities were incorporated and were assumed to be constant at different pressures. Oil viscosity varied with the pressure because solution gas has a significant effect on it. Water viscosity was kept constant. Oil gravity, gas specific gravity, water specific gravity, formation-volume factor (FVF) for oil and gas, and solution-gas/oil ratio were assigned with values often found in real oil fields.
Manage Fields With Intelligent Surveillance, Production Optimization, and Collaboration
Authors: Denney Dennis
Published: February 2015

This article, written by Senior Technology Editor Dennis Denney, contains highlights of paper SPE 150079, ’Managing Fields Using Intelligent Surveillance, Production Optimization, and Collaboration,’ by Frans G. Van den Berg, SPE, Andrew Mabian, SPE, Ronald Knoppe, Edwin Van Donkelaar, Frans Terlaan, and Valentin Koldunov, SPE, Shell, and Rufina Lameda, Science Applications International Corporation, prepared for the 2012 SPE Intelligent Energy International, Utrecht, The Netherlands, 27-29 March. The paper has not been peer reviewed.

Asset professionals in Shell use advanced technologies and processes for field management and optimizing production performance. Real-time monitoring of wells and compressors has become the norm, delivering higher uptime and increased production. Wells and facilities with events or deviations (i.e., exceptions) are highlighted, enabling staff to focus on fixing critical wells and facilities. The information is brought together in collaborative work environments (CWEs) with a video connection to streamline communication between field and office, and to expedite decision making.

Introduction

In general, all of Shell’s new field developments, and redevelopments of existing fields, are equipped with appropriate smart-fields solutions. The elements selected in each field depend on its features and conditions. A screening process is carried out in the early stages of the project to identify requirements and opportunities for implementation. In some cases, application has changed the development concept completely (e.g., field development with smart wells and a remotely controlled platform). In other cases, solutions help improve field management.

Salym Development

Applications were implemented in the West Salym field in western Siberia, Russia. West Salym is the largest of three fields in the Salym Petroleum Development (Fig. 1). Since 2003, approximately 600 wells have been drilled, of which approximately 450 are producers and 150 are water injectors. Field production peaked in 2011 at approximately 180,000 B/D. Production decline would start within 5 years, and production was expected to continue for another 10–15 years. The wells were drilled from drilling pads, each with 16–20 well slots.

Each production well was equipped with an electrical submersible pump (ESP) and a variable drive control. The frequency of the ESPs (and, hence, the pump rate) was optimized weekly for production optimization and ESP-performance optimization and to keep the drawdown on the wells constant and the reservoir pressure above the bubblepoint. Frequent adjustments of the ESP settings were required because the reservoir responded fast to any changes in injection rates.
Comments: The Embargo at 40
Authors: Donnelly John
Published: February 2015

Editor's column

Forty years ago, the global oil market faced shortages, price shocks, and unanswered questions about security of supply. The global oil landscape is drastically different today, and many of the changes grew out of the events that occurred 4 decades ago.

The most dramatic recent change is the growth in US production, revitalized by shale and tight oil output. The United States has drastically reduced its reliance on imported oil and is predicted to soon be the largest producer in the world, surpassing Saudi Arabia and Russia. US oil production has grown more than 50% in the past 5 years, and petroleum imports have fallen from a high of 60% in 2005 to 35% today, according to IHS CERA. That 35% figure is the same as in 1973, when the so-called Arab oil embargo jolted the US and other developed countries into realizing the significance of their dependence on oil supplies from the Middle East and the political and economic ramifications of that reliance.

In addition to oil, US natural gas production has risen by a third since 2005, and shale gas now accounts for more than 40% of total gas output. Long thought a reliable future customer of natural gas, the US is now retrofitting import terminals into gas export facilities.

The 1973 oil embargo—along with consumer governments’ reactive policies such as price controls—helped create gasoline shortages and political panic. It also spawned the encouragement of technological innovation and the opening of new frontiers for oil exploration and production. Developments in the North Sea, Alaska, deepwater US Gulf of Mexico and west Africa, and Canadian oil sands, as well as the growth of other non-OPEC production followed. Since 1973, OPEC production has remained relatively flat at 30 million BOPD, while non-OPEC production has doubled from 27 million BOPD. The crisis also led to increased consumption efficiency and research into alternative forms of energy. After the oil crisis, the leading consuming countries created the International Energy Agency to help guide the need to increase energy security and developed initiatives, such as the Strategic Petroleum Reserve to guard against shortages and potential price spikes. 

While OPEC members and national oil companies (NOCs) have lost market share since that time, they still own the vast majority of the world’s reserves and are much less beholden to private international oil companies (IOCs). NOCs have become much more technically and financially savvy, calling the shots inside their countries and competing head to head outside their countries. NOCs no longer have to rely on large operators to develop their resources. They have the ability to manage projects and apply the latest technology, or can seek help from the large service companies, which are increasingly offering one-stop shop project expertise.
Workforce Competency and Organizational Health Key Drivers in Workforce Optimization
Authors: Glasscock Bill
Published: February 2015

Talent & Technology

In recent years, many energy companies have sought to “cut costs at any cost,” leading in some cases to arbitrary staff reductions with unintended consequences, including reduced productivity, undermined safety, and lower profitability. These companies frequently end up paying a price that exceeds the apparent cost savings. To move beyond simple quantitative formulas and across-the-board cuts, a growing number of energy operations are employing a highly data-driven staffing assessment approach within the context of the business process.

The Workforce Optimization Consulting approach consists of a proprietary methodology, tools, and seasoned consultants focused on helping operators determine and implement the optimum workforces for their facilities. The methodology is grounded in industry best practices and requires a thorough analysis of the total workforce that embraces both quantitative and qualitative criteria. It uses databases of actual, validated oil and gas facility performance. Comparing work practices at a particular site with the top performers in the world yields staffing recommendations that are both realistic and sustainable.

Two key drivers of this smarter, more nuanced approach to managing staffing levels are workforce competency and organizational health. These two different but related criteria directly drive required staffing levels.

From a practical viewpoint, workforce competency comprises a number of factors:

Achieving targeted business objectives: safety, environmental, and financial

Visible and strong leadership at all organizational levels: management, supervision, and workers

Consistent and efficient use of leading performance work processes

Continuous and sustained use of best practices supporting the work process implementation

Individual employee competency: knowledge, training, qualifications, and experience

Employee utilization

These factors must be considered when modifying existing organization structures and staffing levels, and when developing organization and staffing plans for new facilities. Achieving maximum performance for each of these factors takes time. Implementing a Workforce Optimization Consulting solution considers the time required to achieve both individual and organizational maximum competency when determining recommended organization structure and staffing levels. Actual individual employee competency must be considered when determining the number of employees required to perform identified workloads within reasonable time frames and at sustainable work rates.
Comparing North Sea and Deepwater Gulf of Mexico Produced-Water-Treating Systems
Authors: Carpenter Chris
Published: February 2015

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 159713, ’Produced-Water-Treating Systems: Comparison Between North Sea and Deepwater Gulf of Mexico’ by J.M. Walsh, SPE, Shell, and W.J. Georgie, SPE, Maxoil Solutions, prepared for the 2012 SPE Annual Technical Conference and Exhibition, San Antonio, Texas, USA, 8-10 October. The paper has not been peer reviewed.

In terms of platform technologies and extraction strategies, there are fundamental differences between the North Sea and the deepwater Gulf of Mexico (GOM). We consider these systems in light of best practices in water-treating-system design and consider the reasons for deviation from those practices. This process provides insight into the design of water-treating systems in general, emphasizing the importance of carrying out effective water treatment early in the process and the necessity of using large end-of-pipe equipment when this is not possible.

Introduction

Generally speaking, there is a perception that water-treating systems in the North Sea are different from those in the deepwater GOM. Specifically, North Sea systems involve greater use of hydrocyclones, with either no flotation or compact vertical flotation. Deepwater GOM systems are associated with the use of hydrocyclones (but to a lesser degree than in the North Sea) and the use of large horizontal multistage flotation. While these differences are often noted, even greater differences are observed by considering the oil/water/gas-separation system as a whole. The oil/water-separation system includes dehydration of oil and deoiling of water. From the standpoint of the overall integrated oil/water-separation system, the water-treating system is only a part. If a water-treating system is considered an add-on to the overall separation-system (oil/water/gas) design, rather than an integral part, then it will invariably be tasked with a much more difficult challenge (smaller droplets, more-stable emulsions). In that case, it will require large multistage flotation and perhaps tertiary end-of-pipe equipment such as media treatment or filtration.

As shown in Fig. 1, a typical North Sea oil/water-treating system consists of inlet heating where necessary (not shown), followed by first-stage three-phase separation. The produced water is separated from the first-stage separation with enough pressure and is treated through hydrocyclone units.

As shown in Fig. 2, typical deep-water GOM oil/water systems consist of one- or two-stage two-phase separation, followed by three-phase separation. Inlet heating is often not used.  The produced water is separated toward the end of the process at lower operating pressure. The produced water is processed through hydrocyclones through a common collecting vessel operated at a lower pressure and, in many cases, a lower temperature.
Selection for Increased Fiber Length in Cotton Progenies from Acala and Non‐Acala Types
Authors: Paulo de Carvalho Luiz , Correia Farias Francisco José , Isabela da Silva Rodrigues Josiane
Published: February 2015

Cotton (Gossypium hirsutum L. r. latifolium Hutch.) is one of the crops of greatest economic importance in Brazil. The changes in weaving technology, competition with synthetic fibers, and the globalization of cotton and textile production have increased the demand for better quality fibers. One of the characteristics to be improved is fiber length. Brazil traditionally produced and exported longer cotton fibers through the production of G. hirsutum L. r. marie galante, but this race has not been produced during the last 10 yr because of its perennial growth habit, which hinders control of the cotton boll weevil, Anthonomus grandis. This work studied some genetic aspects of fiber length in segregating generations of crosses between two upland cultivars, Guazuncho 2 (PI 606819) and Acala SJ4 (PI 529538). Single‐seed descent protocol and pedigree breeding procedures were used to advance generations. The fibers of the recombinant inbred lines (RILs) and those originated by pedigree procedure were evaluated by high‐volume instrument for length, lint percentage, and strength. The results suggest that it is possible to select materials with improved upper‐half mean length (UHML) that have values approaching a commercial extra‐long staple upland cultivar. A high percentage of the RILs also exhibited a UHML greater than 32 mm. Genetic gain for fiber length from the F4 to the F5 generation was 6.8%, indicating significant variability for UHML. The result indicates that simple methods of intrapopulational breeding may lead to genetic gains in UHML.
Confirmation of a Seed Yield QTL in Soybean
Authors: Fox Carolyn M. , Cary Troy R. , Nelson Randall L. , Diers Brian W.
Published: February 2015

Exotic germplasm can be an important source of genetic diversity for soybean [Glycine max (L.) Merr.] improvement. Previously, four yield quantitative trait loci (QTL) had been identified in a cross between the exotic soybean plant introduction (PI) 68658 and the U.S. cultivar Lawrence. The confirmation of these QTL in other genetic backgrounds will provide further evidence of their usefulness in cultivar development. To confirm the four yield QTL, a population of 117 recombinant inbred lines (RILs) was developed from a backcross using a line from the initial PI 68658 mapping study as the donor parent and LD00–3309, a high‐yielding elite cultivar, as the recurrent parent. The confirmation population was grown in Illinois at two locations in 2008, 2009, and 2010. One yield QTL, linked to marker Satt300 on chromosome (Chr) 5, was confirmed across the experiment (p < 0.01), and the high‐yield allele was contributed by exotic parent PI 68658. This QTL was given the confirmed designation cqSeed yield‐002. A second yield QTL, linked to Satt474 on Chr 14, was significant (p < 0.05) across the experiment, with the high‐yield allele contributed by LD00–3309. Analysis of yield components from one location showed a significant increase in the total number of pods per plant associated with both of these markers. Our results provide evidence that valuable yield QTL exist in exotic soybean germplasm and that these QTL could be used to increase yield in modern cultivars.
LETTER TO THE EDITOR: Management of Vemurafenib Induced Severe Arthralgia and Pyrexia in a
Patient with BRAF V600E Mutated Melanoma: First Experience with a
Switch to Dabrafenib
Authors: Schneider Lars Alexander , Paschka Peter , Scharffetter-Kochanek Karin , Haftek Verena , Treiber Nicolai , Huber Margit Anna
Published: February 2015

The invention of targeted therapy for BRAF mutated advanced stage melanoma has given the patients the
perspective of a possible longer remission of the disease based on taking several pills a day without a further hospital stay.
That is the ideal situation. However, the new drugs are not without side effects. Amongst them, fever and acute arthralgia
are well known. We report on a patient in which these effects were so severe under vemurafenib that we had to stop the
drug twice in the induction phase. Only with concomitant administration of corticosteroids finally a third induction
worked. After 6 months on this therapy we switched the patient to dabrafenib and observed that in this case dabrafenib
was much better tolerated. This is the second report on such a switch between the two licensed BRAF inhibitors because
of side effects so far.
Synthesis and Evaluation of New 2-Iminothiazolidin-4-one and Thiazolidin-2,4-dione Derivatives as Antimicrobial and Anti-inflammatory Agents
Authors: Bayoumi Waleed A. , Abdel-Rhman Shaymaa H. , Shaker Mohamed E.
Published: February 2015

A new series of 2-iminothiazolidin-4-ones and thiazolidin-2,4-diones were designed and synthesized. The target compounds were evaluated for antimicrobial and anti-inflammatory activities, aiming to find a candidate carrying dual activities. The antibacterial activity was determined by cup-diffusion technique and NCCLS broth dilution method. The MICs were determined using 96-well microtitre plates, while the anti-inflammatory activity was determined using carrageenan- induced rat paw edema model. The results revealed that target compounds showed no antifungal activity towards tested Fungi, whereas the antibacterial activity was mainly on Gram-positive bacteria. The anti-inflammatory activity was observed in compounds belonging to the thiazolidin-2,4-dione series. The structures of the newly synthesized compounds were confirmed by physical and spectral data.
Effect of Audiovisual Translation Mode on Perceived Truthfulness of Stories on Video
Authors: Kang Sinuk , Nam Yoonjae
Published: February 2015

We examined an audience's perception of the truthfulness of foreign-language speakers across various audiovisual translation modes. We randomly assigned 89 participants to 1 of 3 conditions: (a) English voiceover of Korean speech, (b) English subtitles over Korean speech, and (c) English
speech only. Korean speakers in the English subtitle and voiceover conditions were judged as more truthful than Korean speakers in the English-speech condition. In addition, the multiple significant positive correlations among personality traits and truthfulness suggest that an audience judging
translation modes may consider personality traits and recreate impressions of the speaker.
Recurrent craniopharyngioma after conformal radiation in children and the burden of treatment
Authors: Klimo Paul , Venable Garrett T. , Boop Frederick A. , Merchant Thomas E.
Published: February 2015

OBJECT

In this paper the authors present their experience treating children with recurrent craniopharyngioma who were initially managed with surgery followed by conformal radiation therapy (CRT).

METHODS

A departmental oncology information system was queried to identify all children (< 18 years old) who received CRT for a craniopharyngioma between 1998 and 2010 (inclusive) and specifically those who experienced tumor progression. For each patient, the authors recorded the type of recurrence (solid, cystic, or both), the time interval to first progression and each subsequent progression, the associated treatment complications, and disease status at last follow-up evaluation.

RESULTS

Among the 97 patients that met criteria for entry into this study, 18 (18.6%) experienced tumor progression (9 cystic, 3 solid, 6 cystic and solid). The median time to first recurrence was 4.62 years (range 1.81–9.11 years). The subgroup included 6 female and 12 male patients with a median age of 7.54 years (range 3.61–13.83 years). Ten patients experienced first progression within 5 years of CRT. The 5- and 10-year treatment-free survival rates for the entire cohort were 89.0% (95% confidence interval [CI] 80.5%–93.9%) and 76.2% (95% CI 64%–85%), respectively. Seven patients had a single episode of progression and 11 had more than 1. The time interval between each subsequent progression was progressively shorter. The 18 patients underwent 38 procedures. The median follow-up duration for this group was 9.32 years (range 4.04–19.0 years). Three patients died, including 1 from perioperative complications.

CONCLUSIONS

Craniopharyngioma progression after prior irradiation is exceedingly difficult to treat and local control is challenging despite repeated surgical procedures. Given our results, gross-total resection may need to be the surgical goal at the time of first recurrence, if possible. Decompressing new cyst formation alone has a low rate of long-term success.
Giant cell tumors of the spine: has denosumab changed the treatment paradigm?
Authors: Goldschlager Tony , Dea Nicolas , Boyd Michael , Reynolds Jeremy , Patel Shreyaskumar , Rhines Laurence D. , Mendel Ehud , Pacheco Marina , Ramos Edwin , Mattei Tobias A. , Fisher Charles G.
Published: February 2015

OBJECT

Giant cell tumors (GCTs) of the spine are rare and complex to treat. They have a propensity for local recurrence and the potential to metastasize. Treatment is currently surgical and presents unique challenges due to the proximity of neural structures and the need for reconstruction. Denosumab has been shown in clinical trials to be an effective treatment for GCT, but has not yet been studied specifically in GCT of the spine or as a surgical adjunct. To the authors' knowledge this is the first such reported series.

METHODS

A multicenter, prospective series of 5 patients with GCT of the spine treated with denosumab were included. Patient demographic data, oncological history, neurological status, tumor staging, treatment details and adverse events, surgical procedure, complications, radiological and histological responses, and patient outcome were analyzed.

RESULTS

All patients were women, with a mean age of 38 years, and presented with pain; 2 patients had additional neurological signs and symptoms. The mean duration of symptoms was 62 weeks. No patient had a prior tumor or metastatic disease at presentation. All patients had Enneking Stage III tumors and were treated with monthly cycles of 120 mg of denosumab, with initial additional loading doses on Days 8 and 15. Patients were given daily supplements of calcium (500 mg) and vitamin D (400 IU). There were no denosumab-related adverse events. All patients had a radiological response to denosumab. One patient failed to have a histological response to denosumab, with > 90% of tumor cells found to be viable on histological investigation.

CONCLUSIONS

This study reports the early experience of using denosumab in the treatment of spinal GCT. The results demonstrate a clinically beneficial radiological response and an impressive histological response in most but not all patients. Further experience with denosumab and longer patient follow-up is required. Denosumab has the potential to change the treatment paradigm for spinal GCT.
Intraoperative and perioperative complications in minimally invasive transforaminal lumbar interbody fusion: a review of 513 patients
Authors: Wong Albert P. , Smith Zachary A. , Nixon Alexander T. , Lawton Cort D. , Dahdaleh Nader S. , Wong Ricky H. , Auffinger Brenda , Lam Sandi , Song John K. , Liu John C. , Koski Tyler R. , Fessler Richard G.
Published: February 2015

OBJECT

Transforaminal lumbar interbody fusion (TLIF) has become one of the preferred procedures for circumferential fusion in the lumbar spine. Over the last decade, advances in surgical techniques have enabled surgeons to perform the TLIF procedure through a minimally invasive approach (MI-TLIF). There are a few studies reported in the medical literature in which perioperative complication rates of MI-TLIF were evaluated; here, the authors present the largest cohort series to date. They analyzed intraoperative and perioperative complications in 513 consecutive MI-TLIF–treated patients with lumbar degenerative disc disease.

METHODS

The authors performed a retrospective review of prospectively collected data on 513 consecutive patients treated over a 10-year period for lumbar degenerative disc disease using MI-TLIF. All patients undergoing either a first-time or revision 1- or 2-level MI-TLIF procedure were included in the study. Demographic, intraoperative, and perioperative data were collected and analyzed using bivariate analyses (Student t-test, analysis of variance, odds ratio, chi-square test) and multivariate analyses (logistic regression).

RESULTS

A total of 513 patients underwent an MI-TLIF procedure, and the perioperative complication rate was 15.6%. The incidence of durotomy was 5.1%, and the medical and surgical infection rates were 1.4% and 0.2%, respectively. A statistically significant increase in the infection rate was seen in revision MI-TLIF cases, and the same was found for the perioperative complication rate in multilevel MI-TLIF cases. Instrumentation failure occurred in 2.3% of the cases. After analysis, no statistically significant difference was seen in the rates of durotomy during revision and multilevel surgeries. There was no significant difference between the complication rates when stratified according to presenting diagnosis.

CONCLUSIONS

To the authors' knowledge, this is the largest study of perioperative complications in MI-TLIF in the literature. A total of 513 patients underwent MI-TLIF (perioperative complication rate 15.6%). The most common complication was a durotomy (5.1%), and there was only 1 surgical wound infection (0.2%). There were significantly more perioperative infections in revision MI-TLIF cases and more perioperative complications in multilevel MI-TLIF cases. The results of this study suggest that MI-TLIF has a similar or better perioperative complication profile than those documented in the literature for open-TLIF treatment of degenerative lumbar spine disease.
Motion characteristics and related factors of Modic changes in the lumbar spine
Authors: Hayashi Tetsuo , Daubs Michael D. , Suzuki Akinobu , Scott Trevor P. , Phan Kevin H. , Ruangchainikom Monchai , Takahashi Shinji , Shiba Keiichiro , Wang Jeffrey C.
Published: February 2015

OBJECT

Most studies of Modic changes (MCs) have focused on investigating the relationship between MCs and lowback pain, whereas the kinematic characteristics and degenerative disc disease associated with MCs are not well understood. To the authors' knowledge, no previous study has reported on the kinematics of MCs. The purpose of this study was to elucidate the relationship of MCs to segmental motion and degenerative disc disease.

METHODS

Four hundred fifty symptomatic patients underwent weight-bearing lumbar kinematic MRI in the neutral, flexion, and extension positions. Segmental displacement and intervertebral angles were measured in 3 positions using computer analysis software. Modic changes, disc degeneration, disc bulging, spondylolisthesis, angular motion, and translational motion were recorded, and the relationship of MCs to these factors was analyzed using a logistic regression model. To control the influence of disc degeneration on segmental motion, angular and translational motion were analyzed according to mild and severe disc degeneration stages. The motion characteristics and disc degeneration among types of MCs were also evaluated.

RESULTS

Multivariate analysis revealed that age, disc degeneration, angular motion, and translational motion were factors significantly related to MCs. In the severe disc degeneration stage, a significant decrease of angular motion and significant increase of translational motion were found in segments with MCs, indicating that a disorder of the endplate had an additional effect on segmental motion. Disc degeneration increased and angular motion decreased significantly and gradually as the type of MC increased. Translational motion was significantly increased with Type 2 MCs.

CONCLUSIONS

Age, disc degeneration, angular motion, and translational motion were significantly linked to MCs in the lumbar spine. The translational motion of lumbar segments increased with Type 2 MCs, whereas angular motion decreased as the type of MC increased, indicating that Type 2 MCs may have translational instability likely due to degenerative changes. A disorder of the endplates could play an important role in spinal instability.
Development of a non–tissue adherent neurosurgical patty and an ex vivo testing system to evaluate adherent characteristics
Authors: Kinoshita Manabu , Taniguchi Mai , Takagaki Masatoshi , Seike Nobuhisa , Hashimoto Naoya , Yoshimine Toshiki
Published: February 2015

Neurosurgical patties are the most frequently used instruments during neurosurgical procedures, and their high performance is required to ensure safe operations. They must offer cushioning, water-absorbing, water-retaining, and non–tissue adherent characteristics. Here, the authors describe a revised neurosurgical patty that is superior in all respects to the conventional patty available in Japan. Patty characteristics were critically and scientifically evaluated using various in vitro assays. Moreover, a novel ex vivo evaluation system focusing on the adherent characteristics of the neurosurgical patty was developed. The proposed assay could provide benchmark data for comparing different neurosurgical patties, offering neurosurgeons objective data on the performance of patties. The newly developed patty was also evaluated in real neurosurgical settings and showed superb performance during various neurosurgical procedures.
Changes in cerebrospinal fluid flow assessed using intraoperative MRI during posterior fossa decompression for Chiari malformation
Authors: Bond Aaron E. , Jane John A. , Liu Kenneth C. , Oldfield Edward H.
Published: February 2015

OBJECT

The authors completed a prospective, institutional review board–approved study using intraoperative MRI (iMRI) in patients undergoing posterior fossa decompression (PFD) for Chiari I malformation. The purpose of the study was to examine the utility of iMRI in determining when an adequate decompression had been performed.

METHODS

Patients with symptomatic Chiari I malformations with imaging findings of obstruction of the CSF space at the foramen magnum, with or without syringomyelia, were considered candidates for surgery. All patients underwent complete T1, T2, and cine MRI studies in the supine position preoperatively as a baseline. After the patient was placed prone with the neck flexed in position for surgery, iMRI was performed. The patient then underwent a bone decompression of the foramen magnum and arch of C-1, and the MRI was repeated. If obstruction was still present, then in a stepwise fashion the patient underwent dural splitting, duraplasty, and coagulation of the tonsils, with an iMRI study performed after each step guiding the decision to proceed further.

RESULTS

Eighteen patients underwent PFD for Chiari I malformations between November 2011 and February 2013; 15 prone preincision iMRIs were performed. Fourteen of these patients (93%) demonstrated significant improvement of CSF flow through the foramen magnum dorsal to the tonsils with positioning only. This improvement was so notable that changes in CSF flow as a result of the bone decompression were difficult to discern.

CONCLUSIONS

The authors observed significant CSF flow changes when simply positioning the patient for surgery. These results put into question intraoperative flow assessments that suggest adequate decompression by PFD, whether by iMRI or intraoperative ultrasound. The use of intraoperative imaging during PFD for Chiari I malformation, whether by ultrasound or iMRI, is limited by CSF flow dynamics across the foramen magnum that change significantly when the patient is positioned for surgery.
Characterization of radiation-induced cavernous malformations and comparison with a nonradiation cavernous malformation cohort
Authors: Cutsforth-Gregory Jeremy K. , Lanzino Giuseppe , Link Michael J. , Brown Robert D. , Flemming Kelly D.
Published: February 2015

OBJECT

The objective of this study was to characterize the clinical features of radiation-induced cavernous malformations (RICMs).

METHODS

The authors retrospectively reviewed the clinical and radiological characteristics of patients with RICMs. The features of these RICMs were then compared with features of nonradiation cavernous malformations (CMs) in 270 patients.

RESULTS

Thirty-two patients with RICMs were identified (56.2% men), with a median age of 31.1 years at RICM diagnosis. The median latency from radiation treatment to RICM diagnosis was 12.0 years (interquartile range 5.0–19.6 years). RICMs were always within the previous radiation port. RICMs were symptomatic at diagnosis in 46.9%, and were associated with symptomatic intracranial hemorrhage at any time in 43.8%. Older age at the time of radiation treatment and higher radiation dose were associated with shorter latency. RICMs tended to be diagnosed at a younger age than nonradiation CMs (median 31.1 vs 42.4 years, respectively; p = 0.054) but were significantly less likely to be symptomatic at the time of diagnosis (46.9% vs 65.8%, respectively; p = 0.036). RICMs were more likely to be multiple CMs than nonradiation CMs (p = 0.0002). Prospectively, the risk of symptomatic hemorrhage was 4.2% for RICMs and 2.3% for nonradiation CMs per person-year (p = 0.556). In the absence of symptoms at presentation, the risk of hemorrhage for RICMs was higher than for nonradiation CMs (4.2% vs 0.35%, respectively; p = 0.118).

CONCLUSIONS

In this patient population, RICMs occurred within the radiation port approximately 12 years after radiation treatment. Compared with nonradiation CMs, RICMs were more likely to occur as multiple CMs, to present at a younger age, and were at least as likely to cause symptomatic hemorrhage.
Instantaneous 3D EEG Signal Analysis Based on Empirical Mode Decomposition and the Hilbert–Huang Transform Applied to Depth of Anaesthesia
Authors: Shih Mu-Tzu , Doctor Faiyaz , Fan Shou-Zen , Jen Kuo-Kuang , Shieh Jiann-Shing
Published: February 2015

Depth of anaesthesia (DoA) is an important measure for assessing the degree to which the central nervous system of a patient is depressed by a general anaesthetic agent, depending on the potency and concentration with which anaesthesia is administered during surgery. We can monitor the DoA by observing the patient’s electroencephalography (EEG) signals during the surgical procedure. Typically high frequency EEG signals indicates the patient is conscious, while low frequency signals mean the patient is in a general anaesthetic state. If the anaesthetist is able to observe the instantaneous frequency changes of the patient’s EEG signals during surgery this can help to better regulate and monitor DoA, reducing surgical and post-operative risks. This paper describes an approach towards the development of a 3D real-time visualization application which can show the instantaneous frequency and instantaneous amplitude of EEG simultaneously by using empirical mode decomposition (EMD) and the Hilbert–Huang transform (HHT). HHT uses the EMD method to decompose a signal into so-called intrinsic mode functions (IMFs). The Hilbert spectral analysis method is then used to obtain instantaneous frequency data. The HHT provides a new method of analyzing non-stationary and nonlinear time series data. We investigate this approach by analyzing EEG data collected from patients undergoing surgical procedures. The results show that the EEG differences between three distinct surgical stages computed by using sample entropy (SampEn) are consistent with the expected differences between these stages based on the bispectral index (BIS), which has been shown to be quantifiable measure of the effect of anaesthetics on the central nervous system. Also, the proposed filtering approach is more effective compared to the standard filtering method in filtering out signal noise resulting in more consistent results than those provided by the BIS. The proposed approach is therefore able to distinguish between key operational stages related to DoA, which is consistent with the clinical observations. SampEn can also be viewed as a useful index for evaluating and monitoring the DoA of a patient when used in combination with this approach.
Glycosaminoglycans and Glycomimetics in the Central Nervous System
Authors: Rowlands Dáire , Sugahara Kazuyuki , Kwok Jessica
Published: February 2015

With recent advances in the construction of synthetic glycans, selective targeting of the extracellular matrix (ECM) as a potential treatment for a wide range of diseases has become increasingly popular. The use of compounds that mimic the structure or bioactive function of carbohydrate structures has been termed glycomimetics. These compounds are mostly synthetic glycans or glycan-binding constructs which manipulate cellular interactions. Glycosaminoglycans (GAGs) are major components of the ECM and exist as a diverse array of differentially sulphated disaccharide units. In the central nervous system (CNS), they are expressed by both neurons and glia and are crucial for brain development and brain homeostasis. The inherent diversity of GAGs make them an essential biological tool for regulating a complex range of cellular processes such as plasticity, cell interactions and inflammation. They are also involved in the pathologies of various neurological disorders, such as glial scar formation and psychiatric illnesses. It is this diversity of functions and potential for selective interventions which makes GAGs a tempting target. In this review, we shall describe the molecular make-up of GAGs and their incorporation into the ECM of the CNS. We shall highlight the different glycomimetic strategies that are currently being used in the nervous system. Finally, we shall discuss some possible targets in neurological disorders that may be addressed using glycomimetics.
Evaluation of ViroCyt® Virus Counter for Rapid Filovirus Quantitation
Authors: Rossi Cynthia , Kearney Brian , Olschner Scott , Williams Priscilla , Robinson Camenzind , Heinrich Megan , Zovanyi Ashley , Ingram Michael , Norwood David , Schoepp Randal
Published: February 2015

Development and evaluation of medical countermeasures for diagnostics, vaccines, and therapeutics requires production of standardized, reproducible, and well characterized virus preparations. For filoviruses this includes plaque assay for quantitation of infectious virus, transmission electron microscopy (TEM) for morphology and quantitation of virus particles, and real-time reverse transcription PCR for quantitation of viral RNA (qRT-PCR). The ViroCyt® Virus Counter (VC) 2100 (ViroCyt, Boulder, CO, USA) is a flow-based instrument capable of quantifying virus particles in solution. Using a proprietary combination of fluorescent dyes that stain both nucleic acid and protein in a single 30 min step, rapid, reproducible, and cost-effective quantification of filovirus particles was demonstrated. Using a seed stock of Ebola virus variant Kikwit, the linear range of the instrument was determined to be 2.8E+06 to 1.0E+09 virus particles per mL with coefficient of variation ranging from 9.4% to 31.5% for samples tested in triplicate. VC particle counts for various filovirus stocks were within one log of TEM particle counts. A linear relationship was established between the plaque assay, qRT-PCR, and the VC. VC results significantly correlated with both plaque assay and qRT-PCR. These results demonstrated that the VC is an easy, fast, and consistent method to quantify filoviruses in stock preparations.
L'aménagement touristique et ses rapports avec l'environnement (Touristic management and environment)
Authors: Michaud J.-L
Published: February 2015

Résumé. - Cet article étudie les conditions de la création et de la conservation d'espaces touristiques, et inversement celles de leur dégradation. Il envisage les conséquences du tourisme sur l'environnement géographique.