Analysis of SIRT1 Gene SNPs and Clinical Characteristics in Medication-Related Osteonecrosis of the Jaw.

Certain genetic factors, including single-nucleotide polymorphisms (SNPs) in the SIRT1 gene, have been linked to medication-related osteonecrosis of the jaw (MRONJ). This study examined four SNPs in the SIRT1 gene and implemented multivariate statistical analysis to analyze genetic and clinical factors in MRONJ patients. Genomic DNA was isolated from peripheral blood samples of 63 patients of European origin treated for MRONJ, and four SNP genotypes in the gene encoding the SIRT-1 protein were determined by Sanger sequencing. The allele frequencies measured in the MRONJ population were compared with allele frequencies measured in the European population in the National Center for Biotechnology Information Allele Frequency Aggregator (NCBI ALFA) database. Genetic and clinical factors were examined with multivariate statistical analysis. A C:A allele distribution ratio of 77.8:22.2 was measured in the rs932658 SNP. In the ALFA project, a C:A allele distribution ratio of 59.9:40.1 was detected in the European population, which was found to be a significant difference (p = 4.5 × 10-5). Multivariate statistical analysis revealed a positive correlation (0.275) between the genotype of SNP rs932658 and the number of stages improved during appropriate MRONJ therapy. It is concluded that allele A in SNP rs932658 in the SIRT1 gene acts as a protective factor in MRONJ.

Related adjustment of firm production after demand shocks.

Multiproduct firms often diversify into technologically related activities to exploit efficiencies of joint production; however, unrelated products in the company's portfolio provide access to distinct markets and can help to avoid industry-specific shocks. Yet, the underlying mechanisms of related and unrelated diversification are still poorly understood. Here we investigate diversification decisions of firms in periods when corporations' markets are hit by a demand shocks. In these times, cost efficiency considerations might drive firms to reduce costs by narrowing product portfolios and focusing on combinations of technologically related products, in which economies of scope and mutual capabilities can be exploited. To test this hypothesis, we consider two measures of demand shocks, decreasing sales volumes on the product market and increasing import competition; and analyze their association with changes of product portfolios of Hungarian firms in the 2003-2012 period. We find that production has become more coherent in terms of technological relatedness after firms were exposed to demand shocks. Evidence suggests related adjustment of firm production after demand shocks such that products unrelated to firms' core product are dropped from the portfolio but related products are added.

Initial experiences with the use of covered stents in endovascular treatment of aortoiliac stenoocclusive diseases / Aortoiliacalis stenoocclusiv betegség fedett sztentekkel végzett endovascularis ellátásával szerzett kezdeti tapasztalataink

Introduction: Treatment for complex aortoiliac stenoocclusive disease traditionally is open surgical repair. Endovascular approach is associated with less perioperative stress for the patient, and is a reasonable solution. Covered stent implantation is an alternative treatment option in this patient population even in the case of aortobiiliac or aortobifemoral bypasses. Objective: Assessing outcomes of aortoiliac covered stent implantation at our vascular center. Method: We retrospectively analysed the data of 36 prospectively registered, consecutive patients who underwent aortoiliac covered stent implantations at our department between the 1th November 2019 and 30th September 2021. Medical records, perioperative complications, preoperative and postoperative Rutherford stages and ankle-brachial index were recorded. One-year survival and primary patency as primary endpoints were presented on Kaplan-Meier curve. Our secondary endpoints were change of the ankle-brachial index and Rutherford stage, and the incidence of the major amputation. Results: 36 patients were included in the study. Mean follow-up time was 12 +/- 6.9 months. TASC C-D aortoiliac lesions were the indication of the procedures in 72.2% (n = 26). Patients had critical limb ischaemia in 44% (n = 16). In 64% (n = 23), interventions were performed via percutaneous puncture. In-hospital stay was 5 +/- 7 days. Perioperative bleeding and reoperation occured in 4 (11.1%) and 6 (16.6%) cases, respectively. Perioperative mortality was zero. The one-year survival and primary patency were 94.3% and 91.4%, respectively. The postoperative Rutherford stage (3 [2] vs. 1 [1]; p < 0.001) and ankle-brachial index (0.4 [0.55] vs. 1 [0.4]; p < 0.001) improved significantly compared to the preoperative ones. Unplanned major amputation was not performed. Conclusion: Significant clinical improvement with low perioperative mortality, acceptable morbidity and high one-year primary patency and survival can be obtained by the use of covered stents in the treatment of aortoiliac stenoocclusive disease. This procedure can be an alternative to open surgical repair.

Understanding hesitancy with revealed preferences across COVID-19 vaccine types.

Many countries have secured larger quantities of COVID-19 vaccines than their population is willing to take. The abundance and the large variety of vaccines created not only an unprecedented intensity of vaccine related public discourse, but also a historical moment to understand vaccine hesitancy better. Yet, the heterogeneity of hesitancy by vaccine types has been neglected in the existing literature so far. We address this problem by analysing the acceptance and the assessment of five vaccine types. We use information collected with a nationally representative survey at the end of the third wave of the COVID-19 pandemic in Hungary. During the vaccination campaign, individuals could reject the assigned vaccine to wait for a more preferred alternative that enables us to quantify revealed preferences across vaccine types. We find that hesitancy is heterogenous by vaccine types and is driven by individuals' trusted source of information. Believers of conspiracy theories are more likely to evaluate the mRNA vaccines (Pfizer and Moderna) unacceptable. Those who follow the advice of politicians are more likely to evaluate vector-based (AstraZeneca and Sputnik) or whole-virus vaccines (Sinopharm) acceptable. We argue that the greater selection of available vaccine types and the free choice of the individual are desirable conditions to increase the vaccination rate in societies.

Urban hierarchy and spatial diffusion over the innovation life cycle.

Successful innovations achieve large geographical coverage by spreading across settlements and distances. For decades, spatial diffusion has been argued to take place along the urban hierarchy. Yet, the role of geographical distance was difficult to identify in hierarchical diffusion due to missing data on spreading events. In this paper, we exploit spatial patterns of individual invitations sent from registered users to new users over the entire life cycle of a social media platform. We demonstrate that hierarchical diffusion overlaps with diffusion to close distances and these factors co-evolve over the life cycle. Therefore, we disentangle them in a regression framework that estimates the yearly number of invitations sent between pairs of towns. We confirm that hierarchical diffusion prevails initially across large towns only but emerges in the full spectrum of settlements in the middle of the life cycle when adoption accelerates. Unlike in previous gravity estimations, we find that after an intensifying role of distance in the middle of the life cycle a surprisingly weak distance effect characterizes the last years of diffusion. Our results stress the dominance of urban hierarchy in spatial diffusion and inform future predictions of innovation adoption at local scales.

Geographies of the global co-editor network in oncology.

The co-editor networks of academic journals are generally examined at the journal level. This paper investigates the geographies of the global co-editor network in oncology through the lens of cities. After using different network methods to analyze the global co-editor network, we found that the network can be characterized by a core-periphery structure. The dense core is occupied by many highly interconnected cities, whereas the periphery contains many cities maintaining loose connections with the core cities. The core shows an asymmetric dual sub-core structure. The greater sub-core is constituted by Northern American cities with New York, Washington DC, Boston, Houston, and Los Angeles in the center, whereas the smaller sub-core is formed by Asian cities and centered on Tokyo, Seoul, Osaka, Beijing, and Shanghai. The European core cities do not form a well-outlined sub-core but produce a ringlike shape around the Northern American core. This structure of the co-editor network is a consequence of the prestige effect still characterizing global science. Many European and Chinese journals tend to employ Northern American editors (US-based editors in the first place) to help increase the reputation of the journal. However, US-based journals are more interested in recruiting American editors from the top-ranked national cancer centers and universities rather than outside of the country.

Allocating vaccines to remote and on-site workers in the tradable sector.

Vaccination may be the solution to the pandemic-induced health crisis, but the allocation of vaccines is a complex task in which ethical, economic and social considerations are important. The biggest challenge is to use the limited number of vaccines available in a way that protects vulnerable groups, prevents further spread of infection, and reduces economic uncertainty. We argue that once the vaccination of healthcare workers and the most vulnerable groups has been completed, prioritizing the vaccination of on-site workers is important not only to slow the spread of the infection, but also to ensure the smooth running of economic production. We propose a simple economic model where remote and on-site workers are complementary to each other in the short run, thus a negative shock to the supply of either one may decrease the demand for the other, leading to unemployment. By illustrating the model using pre-Covid employment data from Sweden and Hungary, we show that the optimal vaccine allocation between remote and on-site workers in the tradable sector should be based on different proportions depending on the relative infection risk of on-site workers and the degree of vaccine availability. As long as the number of vaccines is limited and on-site workers are at higher risk of infection, they should be preferred in general. However, as more vaccines become available, countries like Sweden, where the share of occupations that can be done remotely is higher shall start immunize remote workers. In Hungary, where on-site work is dominant in the tradable sector, continued vaccination of on-site workers is more beneficial.

Understanding European integration with bipartite networks of comparative advantage.

Core objectives of European common market integration are convergence and economic growth, but these are hampered by redundancy, and value chain asymmetries. The challenge is how to harmonize labor division to reach global competitiveness, meanwhile bridging productivity differences across the EU. We develop a bipartite network approach to trace pairwise co-specialization by applying the revealed comparative advantage method within and between the EU15 and Central and Eastern European (CEE). This approach assesses redundancies and the division of labor in the EU at the level of industries and countries. We find significant co-specialization among CEE countries but a diverging specialization between EU15 and CEE. Productivity increases in those CEE industries that have co-specialized with other CEE countries after EU accession, while co-specialization across CEE and EU15 countries is less related to productivity growth. These results show that a division of sectoral specialization can lead to productivity convergence between EU15 and CEE countries.

Universal patterns of long-distance commuting and social assortativity in cities.

Millions commute to work every day in cities and interact with colleagues, partners, friends, and strangers. Commuting facilitates the mixing of people from distant and diverse neighborhoods, but whether this has an imprint on social inclusion or instead, connections remain assortative is less explored. In this paper, we aim to better understand income sorting in social networks inside cities and investigate how commuting distance conditions the online social ties of Twitter users in the 50 largest metropolitan areas of the United States. An above-median commuting distance in cities is linked to more diverse individual networks, moreover, we find that longer commutes are associated with a nearly uniform, moderate reduction of overall social tie assortativity across all cities. This suggests a universal relation between long-distance commutes and the integration of social networks. Our results inform policy that facilitating access across distant neighborhoods can advance the social inclusion of low-income groups.

Inequality is rising where social network segregation interacts with urban topology.

Social networks amplify inequalities by fundamental mechanisms of social tie formation such as homophily and triadic closure. These forces sharpen social segregation, which is reflected in fragmented social network structure. Geographical impediments such as distance and physical or administrative boundaries also reinforce social segregation. Yet, less is known about the joint relationships between social network structure, urban geography, and inequality. In this paper we analyze an online social network and find that the fragmentation of social networks is significantly higher in towns in which residential neighborhoods are divided by physical barriers such as rivers and railroads. Towns in which neighborhoods are relatively distant from the center of town and amenities are spatially concentrated are also more socially segregated. Using a two-stage model, we show that these urban geography features have significant relationships with income inequality via social network fragmentation. In other words, the geographic features of a place can compound economic inequalities via social networks.

Long-term analysis of the results of aorto-bifemoral bypass surgery for diffuse aorto-biiliac occlusive disease / Az aortobiiliacalis occlusiv érbetegség miatt végzett aortobifemoralis bypass mutétek hosszú távú eredményeinek elemzése.

Összefoglaló. Bevezetés: A diffúz aortobiiliacalis érszakasz occlusiv betegségének kezelésére alkalmazott aortobifemoralis bypass szerepe csökken az endovascularis mutétek térnyerése miatt. Célkituzés: A vizsgálat célja volt a modern invazív kezelés korszakában a perioperatív és a hosszú távú eredmények elemzése aortobiiliacalis bypass után, melyek összehasonlíthatók az endovascularis megoldások eredményeivel. Módszerek: A retrospektív, egycentrumú vizsgálat során a Semmelweis Egyetem Városmajori Szív- és Érgyógyászati Klinikájának Érsebészeti és Endovaszkuláris Tanszékén 2006. 01. 01. és 2017. 12. 31. között occlusiv aortoiliacalis atherosclerosis miatt primer aortobifemoralis bypass mutéten átesett 419 beteg (átlagéletkor: 62,2 év, SD: ± 8,22; 224 férfi, 53%) adatait elemeztük. Eredmények: A posztoperatív 30 napon belüli mortalitás 5,01%, a késoi mortalitás 10,98% és 29,59% volt 12, illetve 60 hónap után. A betegek 12,57%-ánál történt korai reoperáció, késoi reoperáció 32 (8%) betegnél vált szükségessé. A graft elsodleges nyitva maradása 88,65% és 81,15% volt 12, illetve 60 hónap után. 21 betegnél történt amputáció (6,29%); 57,14%-ban femoralis, 35,71%-ban cruralis szinten, 7,14%-ban a boka szintje alatt. Az amputációkra 35,71%-ban a bypasst követo 30 napon belül, további 35,71%-ban 2 éven belül került sor. Az esetek 35,63%-ában lépett fel egyéb szövodmény; a leggyakoribbak: mutétet igénylo posztoperatív hernia (6,89%), cardiovascularis szövodmény (4,19%), lágyéki nyirokcsorgás vagy sebgyógyulási zavar (4,79%). Következtetés: Eredményeink alapján e betegcsoportban az aortobifemoralis bypass elfogadható, de nem jelentéktelen perioperatív halálozással és magas morbiditással jár. A graft hosszú távú nyitva maradása jó, de az újabb érmutét mind rövid, mind hosszú távon relatíve gyakori. A kevésbé invazív technikák eredményeinek összehasonlítása indokolt a hosszú szakaszú (TASC C, D) elváltozások esetén. Orv Hetil. 2021; 162(3): 99-105. INTRODUCTION: The role of aorto-bifemoral bypass in the treatment of diffuse aorto-biiliac occlusive disease decreases in the era of endovascular surgery. OBJECTIVE: The aim of the study was to analyse the early and long-term postoperative results of aorto-bifemoral bypass in a recent time period. These results may be used as a baseline to compare the results of endovascular procedures. METHODS: In a retrospective, single-center study, the data of 419 patients (mean age: 62.2 years, SD: ± 8.22; 224 men, 53%) who underwent primary aorto-bifemoral bypass due to occlusive aorto-iliac atherosclerosis from 01. 01. 2006 to 31. 12. 2017 at the Department of Vascular and Endovascular Surgery of Semmelweis University Heart and Vascular Center were analysed. RESULTS: Postoperative mortality within 30 days was 5.01%, late mortality was 10.98% and 29.59% after 12 and 60 months, respectively. 12.57% of the patients needed early reoperation and late reoperation was required in 32 cases (8%). The primary graft patency was 88.65% and 81.15% after 12 and 60 months, respectively. 21 patients underwent amputation (6.29%); 57.14% at the femoral level, 35.71% at the crural level and 7.14% below the ankle level. Amputations were performed in 35.71% of the cases within 30 days after the bypass and an additional 35.71% within 2 years. Other complications occurred in 35.63% of the cases; the most common causes were postoperative hernia requiring surgery (6.89%), cardiovascular complication (4.19%) and inguinal wound healing disorders (4.79%). CONCLUSION: Based on our results, aorto-bifemoral bypass surgery is associated with acceptable but not insignificant perioperative mortality and high morbidity in this group of patients. The graft patency is favourable in the long term, however, additional vascular reintervention is common in short and long term as well. Short- and long-term results of percutaneous endovascular techniques in diffuse aorto-biiliac disease (TASC C and D lesions) are suggested to be compared to these recent results of open surgery. Orv Hetil. 2021; 162(3): 99-105.

Exploring the changing geographical pattern of international scientific collaborations through the prism of cities.

Science is becoming increasingly international in terms of breaking down walls in its pursuit of high impact. Despite geographical location and distance still being major barriers for scientific collaboration, little is known about whether high-impact collaborations are similarly constrained by geography compared to collaborations of average impact. To address this question, we analyze Web of Science (WoS) data on international collaboration between global leader cities in science production. We report an increasing intensity of international city-city collaboration and find that average distance of collaboration of the strongest connections has slightly increased, but distance decay has remained stable over the last three decades. However, high-impact collaborations span large distances by following similar distance decay. This finding suggests that a larger geographical reach of research collaboration should be aimed for to support high-impact science. The creation of the European Research Area (ERA) represents an effective action that has deepened intracontinental research collaborations and the position of the European Union (EU) in global science. Yet, our results provide new evidence that global scientific leaders are not sufficiently collaborative in carrying out their big science projects.

The role of geography in the complex diffusion of innovations.

The urban-rural divide is increasing in modern societies calling for geographical extensions of social influence modelling. Improved understanding of innovation diffusion across locations and through social connections can provide us with new insights into the spread of information, technological progress and economic development. In this work, we analyze the spatial adoption dynamics of iWiW, an Online Social Network (OSN) in Hungary and uncover empirical features about the spatial adoption in social networks. During its entire life cycle from 2002 to 2012, iWiW reached up to 300 million friendship ties of 3 million users. We find that the number of adopters as a function of town population follows a scaling law that reveals a strongly concentrated early adoption in large towns and a less concentrated late adoption. We also discover a strengthening distance decay of spread over the life-cycle indicating high fraction of distant diffusion in early stages but the dominance of local diffusion in late stages. The spreading process is modelled within the Bass diffusion framework that enables us to compare the differential equation version with an agent-based version of the model run on the empirical network. Although both model versions can capture the macro trend of adoption, they have limited capacity to describe the observed trends of urban scaling and distance decay. We find, however that incorporating adoption thresholds, defined by the fraction of social connections that adopt a technology before the individual adopts, improves the network model fit to the urban scaling of early adopters. Controlling for the threshold distribution enables us to eliminate the bias induced by local network structure on predicting local adoption peaks. Finally, we show that geographical features such as distance from the innovation origin and town size influence prediction of adoption peak at local scales in all model specifications.

Brokering the core and the periphery: Creative success and collaboration networks in the film industry.

In collaboration-based creative industries, such as film production, creators in the network core enjoy prestige and legitimacy that are key for creative success. However, core creators are challenged to maintain diverse access to new ideas or alternative views that often emerge from the network periphery. In this paper, we demonstrate that creators in the network core can increase the probability of their creative success by brokering peripheral collaborators to the core. The argument is tested on a dynamic collaboration network of movie creators constructed from a unique dataset of Hungarian feature films for the 1990-2009 period. We propose a new way to capture brokers' role in core/periphery networks and provide evidence that being in the core and at the same time bridging between the core and the periphery of the network significantly increases the likelihood of award winning.

Social capital predicts corruption risk in towns.

Corruption is a social plague: gains accrue to small groups, while its costs are borne by everyone. Significant variation in its level between and within countries suggests a relationship between social structure and the prevalence of corruption, yet, large-scale empirical studies thereof have been missing due to lack of data. In this paper, we relate the structural characteristics of social capital of settlements with corruption in their local governments. Using datasets from Hungary, we quantify corruption risk by suppressed competition and lack of transparency in the settlement's awarded public contracts. We characterize social capital using social network data from a popular online platform. Controlling for social, economic and political factors, we find that settlements with fragmented social networks, indicating an excess of bonding social capital has higher corruption risk, and settlements with more diverse external connectivity, suggesting a surplus of bridging social capital is less exposed to corruption. We interpret fragmentation as fostering in-group favouritism and conformity, which increase corruption, while diversity facilitates impartiality in public life and stifles corruption.

International Collaboration and Spatial Dynamics of US Patenting in Central and Eastern Europe 1981-2010.

How did post-socialist transition and a parallel shift in international labor division restructure regional innovation systems in Central and Eastern Europe? This question is increasingly important, because current EU innovation policy is combined with regional development in Smart Specialization Strategies; however, spatial trends of innovation in Central and Eastern Europe are not fully understood which might lead to less than perfectly efficient policy. In this paper we describe the spatial dynamics of inventor activity in the Czech Republic, Hungary, Poland and Slovakia between 1981 and 2010 -a period that covers both the late socialist era and the post-socialist transition. Cleaning and analyzing the publicly available data from the United States Patent and Trademark Office we illustrate that Central and Eastern European patents made in international co-operations with partners outside the region receive more citations than those Central and Eastern European patents that lack international co-operation. Furthermore, the technological portfolio of the former patents has become increasingly independent from the technological portfolio of the latter class. A town-level analysis of the applicant-inventor ties reveals that inventors have started to work for foreign assignees in those towns where no innovation activity had been recorded before. However, the positive effect does not last long and patenting seems to be only periodic in the majority of these towns. Therefore, innovation policy in Central and Eastern European countries, as well as in other less developed regions, shall foster synergies between international and domestic collaborations in order to decrease regional disparities in patenting.

Geographies of an Online Social Network.

How is online social media activity structured in the geographical space? Recent studies have shown that in spite of earlier visions about the "death of distance", physical proximity is still a major factor in social tie formation and maintenance in virtual social networks. Yet, it is unclear, what are the characteristics of the distance dependence in online social networks. In order to explore this issue the complete network of the former major Hungarian online social network is analyzed. We find that the distance dependence is weaker for the online social network ties than what was found earlier for phone communication networks. For a further analysis we introduced a coarser granularity: We identified the settlements with the nodes of a network and assigned two kinds of weights to the links between them. When the weights are proportional to the number of contacts we observed weakly formed, but spatially based modules resemble to the borders of macro-regions, the highest level of regional administration in the country. If the weights are defined relative to an uncorrelated null model, the next level of administrative regions, counties are reflected.

Development and initial validation of an endoscopic part-task training box.

BACKGROUND AND STUDY AIMS: There is currently no objective and validated methodology available to assess the progress of endoscopy trainees or to determine when technical competence has been achieved. The aims of the current study were to develop an endoscopic part-task simulator and to assess scoring system validity. METHODS: Fundamental endoscopic skills were determined via kinematic analysis, literature review, and expert interviews. Simulator prototypes and scoring systems were developed to reflect these skills. Validity evidence for content, internal structure, and response process was evaluated. RESULTS: The final training box consisted of five modules (knob control, torque, retroflexion, polypectomy, and navigation and loop reduction). A total of 5 minutes were permitted per module with extra points for early completion. Content validity index (CVI)-realism was 0.88, CVI-relevance was 1.00, and CVI-representativeness was 0.88, giving a composite CVI of 0.92. Overall, 82 % of participants considered the simulator to be capable of differentiating between ability levels, and 93 % thought the simulator should be used to assess ability prior to performing procedures in patients. Inter-item assessment revealed correlations from 0.67 to 0.93, suggesting that tasks were sufficiently correlated to assess the same underlying construct, with each task remaining independent. Each module represented 16.0 % - 26.1 % of the total score, suggesting that no module contributed disproportionately to the composite score. Average box scores were 272.6 and 284.4 (P = 0.94) when performed sequentially, and average score for all participants with proctor 1 was 297.6 and 308.1 with proctor 2 (P = 0.94), suggesting reproducibility and minimal error associated with test administration. CONCLUSION: A part-task training box and scoring system were developed to assess fundamental endoscopic skills, and validity evidence regarding content, internal structure, and response process was demonstrated.

Laparoscopic cholecystectomy: What is the price of conversion?

BACKGROUND: Laparoscopic cholecystectomy (LC) is the gold standard procedure for gallbladder removal. Conversion to an open procedure is sometimes deemed necessary, especially in complex cases in which a prolonged laparoscopic operative time is anticipated. A prolonged LC case is thought to be associated with increased complications and cost and therefore generally discouraged. The purpose of this study was to test this assumption, and compare outcomes and cost of converted and prolonged LC cases. METHODS: By using institutional National Surgical Quality Improvement Program and financial databases, we retrospectively reviewed and compared prolonged laparoscopic cases (Long-LC) with converted (CONV) procedures. Surgical times, length of stay (LOS), 30-day complications, operative room, and total hospital charges were compared between the 2 groups. RESULTS: A total of 101 Long-LC and 66 CONV cases met our inclusion criteria. Long-LC cases were 19 minutes longer than CONV cases (123 vs 104 min; P < .01). No differences in postoperative complications were found between the 2 groups (P > .05). When Poisson regression was used, we found that LOS was significantly shorter in the Long-LC compared with CONV group (1 day vs 4 days; P < .01). Long-LC cases had greater operative charges ($15,278 vs $13,128; P < .01). However, hospital charges for Long-LC cases were 26% less than for CONV cases ($23,946 vs $32,446; P < .01). CONCLUSION: Conversion is associated with a 3-day increase in LOS. Long-LC cases have greater operative room charges, but overall hospital charges were 26% less than CONV cases. Our data suggest that decision making regarding conversion should focus on safety and not time considerations.

Laparoscopic cholecystectomy after a quarter century: why do we still convert?

BACKGROUND: Laparoscopic cholecystectomy (LC) is the gold standard procedure for gallbladder removal. However, conversion to open surgery is sometimes needed. The factors underlying a surgeon's decision to convert a laparoscopic case to an open case are complex and poorly understood. With decreasing experience in open cholecystectomy, this procedure is however no longer the "safe" alternative it once was. With such an impending paradigm shift, this study aimed to identify the main reasons for conversion and ultimately to develop guidelines to help reduce the conversion rates. METHODS: Using the National Surgical Quality Improvement Program (NSQIP) database and financial records, the authors retrospectively reviewed 1,193 cholecystectomies performed at their institution from 2002 to 2009 and identified 70 conversions. Two independent surgeons reviewed the operative notes and determined the reasons for conversion. The number of ports at the time and the extent of dissection before conversion were assessed and used to create new conversion categories. Hospital length of stay (LOS), 30-day complications, operative times and charges, and hospital charges were compared between the new groups. RESULTS: In 91% of conversion cases, the conversion was elective. In 49% of these conversions, the number of ports was fewer than four. According to the new conversion categories, most conversions were performed after minimal or no attempt at dissection. There were no differences in LOS, complications, operating room charges, or hospital charges between categories. Of the six emergent conversions (9%), bleeding and concern about common bile duct (CBD) injury were the main reasons. One CBD injury occurred. CONCLUSIONS: In 49% of the cases, conversion was performed without a genuine attempt at laparoscopic dissection. Considering this new insight into the circumstances of conversion, the authors recommend that surgeons make a genuine effort at a laparoscopic approach, as reflected by placing four ports and trying to elevate the gallbladder before converting a case to an open approach.