Transportation systems in the Arctic: a systematic literature review using textometry

Keywords: Arctic, Northern Sea Route, North West Passage, Shipping, Ports, Hinterland, Tourism

Transportation systems in the Arctic: a systematic literature review using textometry

Transportation systems in the Arctic: a systematic literature review

Introduction

One of global warming's effects is the melting of ice caps in Polar areas and especially in the Arctic region. The Arctic is warming more than twice as fast as the rest of the planet, rapidly increasing glacier and sea ice melt [START_REF] Quinn | Short-lived pollutants in the Arctic: their climate impact and possible mitigation strategies[END_REF]. This ice melt makes shipping possible for a certain period in the year along the coasts of Russia, with the Northern Sea Route (NSR) and Canada with the North West Passage (NWP) (Lasserre and Faury, 2019). Moreover, the ice melt influences the commercial viability of these routes [START_REF] Bekkers | Melting ice caps and the economic impact of opening the Northern Sea Route[END_REF]. Potential profitability comes from a reduction in distance for transcontinental shipping, and especially the Asia-Europe shipping [START_REF] Lasserre | Case studies of shipping along Arctic routes. Analysis and profitability perspectives for the container sector[END_REF].

The ice melt has two main consequences for transportation. First, it opens a passage for vessels crossing in theNorthern American area (Chenier et al, 2016) and in the Eurasian area [START_REF] Solvang | An exploratory study on the Northern Sea Route as an alternative shipping passage[END_REF]. These routes may not only be cheaper and faster solutions for transcontinental transportation, but they could also become less-polluting routes overall [START_REF] Theocharis | Arctic shipping: A systematic literature review of comparative studies[END_REF][START_REF] Zhang | Reducing black carbon emissions from Arctic shipping: Solutions and policy implications[END_REF]. Second, this melt also enables easier exploitation and transportation of resources to and from the Arctic area. It is especially true considering oil fields [START_REF] Remishevskaia | Actual problems of effective and safe development of the arctic oil and gas fields using the case of the Yamal Peninsula[END_REF] and liquefied natural gas fields [START_REF] Ritz | A strategic perspective on competition between pipeline gas and LNG[END_REF].

During the last few decades and with an increasing rate, studies have been performed by private, institutional, and academic sectors. These studies cover transportation through, from and to the Arctic area as well as infrastructures located in the Arctic. Transportation studies cover tramping and oil transportation [START_REF] Cariou | Relevance of the Northern Sea Route (NSR) for bulk shipping[END_REF], container shipping [START_REF] Xu | Economic feasibility of an NSR/SCR-combined container service on the Asia-Europe lane: a new approach dynamically considering sea ice extent[END_REF][START_REF] Cheaitou | Liner shipping service optimisation with reefer containers capacity: An application to northern Europe-South America trade[END_REF] and also cruise shipping [START_REF] Webb | Activity patterns and speeds of large cruise ships in Southeast Alaska[END_REF]Kajan, 2014;[START_REF] Dawson | Identifying and evaluating adaptation strategies for cruise tourism in Arctic Canada[END_REF]. Infrastructures in the Arctic have been studied from the perspective of ports with their capacity, development and specific requirements (Allen, 2015;[START_REF] Krivoshchekov | Seaport Concentration and Competition Development in the Arctic Region of Russia along the North Sea Route[END_REF]; from the perspective of the access to hinterland through the different corridors and modes of transport [START_REF] Alix | Maritime route; land route; polar route? Transportation strategies to connect Asia and Europe[END_REF][START_REF] Antipov | Problems of Implementation of Freights Transportation in the Arctic Zone of the Russian Federation by Sea[END_REF][START_REF] Alklychev | Railroad Transportation for the Territorial Development of Siberia and the Far East[END_REF]; and from a free zone perspective [START_REF] Lavissière | Free Ports as a tool to develop the navigation in the Arctic[END_REF].

In this short time, a complete field of research has emerged and structured itself around a few major approaches. Not only are academic articles increasing in numbers, but books have also been dedicated to transportation in the Arctic with its specific issues. Thematic literature reviews have also been carried out. First, [START_REF] Lasserre | Case studies of shipping along Arctic routes. Analysis and profitability perspectives for the container sector[END_REF] looked at the studies that compared the Arctic and non Arctic routes. He based his research on 26 academic papers dealing with such comparisons. Then, [START_REF] Meng | Viability of transarctic shipping routes: a literature review from the navigational and commercial perspectives[END_REF] carried out a literature review on the theme of Arctic navigation and commercial opportunities. This literature review is based on 25 academic papers. A few years ago, [START_REF] Theocharis | Arctic shipping: A systematic literature review of comparative studies[END_REF] completed a third literature review on the different research methods used to compare the existing shipping routes and the Arctic routes. This thematic literature review on methodology is based on 33 academic papers. While these three major literature reviews focus on very specific aspects in the field of Arctic transportation, there is currently no systemic literature review of concerning the whole field. This leaves Arctic transportation scholars with no overall picture of the current academic literature in their field.

The aim of the present paper is to bridge this gap. We present a systematic literature review of the Arctic transportation field. We include academic articles treating the whole scope of Arctic transportation: geographically with a coverage of NSR and NWP; in terms of transportation with academic papers on ports in the Arctic; shipping in the Arctic; tourism; and legal, institutional and geopolitical implications that the exploitation of the Arctic as a transportation route creates. Moreover, we compare the concerns of the academic community with the professional concerns that professional press about this field addresses and exposes.

For this systematic literature review, we take a textometric approach. This linguistics-based method has been used in other management studies [START_REF] Macke | Systematic literature review on sustainable human resource management[END_REF], but also in maritime studies [START_REF] Mandjak | Port marketing from a multidisciplinary perspective: A systematic literature review and lexicometric analysis[END_REF][START_REF] Fedi | The facilitating role of IT systems for legal compliance: the case of port community systems and container Verified Gross Mass (VGM)[END_REF] in order to obtain an overall picture of the literature published in the field.

Method

Characteristics of a systematic literature review

Systematic literature reviews began in medical science and then diffused to psychology, information technology, and social sciences [START_REF] Senivongse | Utilizing a systematic literature review to develop an integrated framework for information and knowledge management systems[END_REF]. They cover a specific topic in the academic literature in an exhaustive manner. The first aim is to build a state of the art. Such reviews also enable academic communities to find new topics for research and to identify specific gaps to fill while summarizing knowledge on the specific topic. In the field of transportation, several types of systematic reviews can be identified: methodological [START_REF] Woo | Seaport research: A structured literature review on methodological issues since the 1980s[END_REF], emerging topics [START_REF] Moros-Daza | Port Community Systems: A structured literature review[END_REF] or syntheses of large existing literature [START_REF] Mandjak | Port marketing from a multidisciplinary perspective: A systematic literature review and lexicometric analysis[END_REF].

A systematic literature review "is based on a clearly formulated question, identifies relevant studies, appraises their quality and summarizes the evidence by use of explicit methodology. It is the explicit and systematic approach that distinguishes systematic reviews from traditional reviews and commentaries" (Khan et al., 2003: 118).

In order to carry out the systematic literature review on Arctic transportation systems, we followed the steps suggested by [START_REF] Durach | A new paradigm for systematic literature reviews in supply chain management[END_REF] and commonly accepted in management science and economy [START_REF] Tranfield | Towards a methodology for developing evidenceinformed management knowledge by means of systematic review[END_REF][START_REF] Mandjak | Port marketing from a multidisciplinary perspective: A systematic literature review and lexicometric analysis[END_REF]. These six steps are the following: (1) defining the research question, (2) determining the required characteristics of primary studies, (3) retrieving a sample of potentially relevant literature, (4) selecting the relevant literature, (5) synthesizing the literature, and (6) reporting the results.

Steps in defining the relevant literature base

Step 1: Research question Literature suggests that the topic of a systematic literature review, as well as the research questions, should be chosen before starting to perform the review (Boell and Cecez-Kecmanovic, 2015;[START_REF] Khan | Five steps to conducting a systematic review[END_REF]. This approach led us to three main research questions:

• QR1: what is the state of the art of Arctic transportation?

• QR2: does academic research on Arctic transportation match with professional concerns about the topic?

• QR3: what are the perspectives of future research in the field?

Step 2: Required characteristics of primary studies Our literature review is composed of three textometric analyses. The first textometric analysis is restricted to academic work published in English in peer review journals. We chose this type of research document because it is the most representative of current research that is approved by the academic community researching transportation. We systematically searched for and included these articles. We did not include books, book chapters written by scholars, articles selected for publication in conference proceedings, Masters or Ph.D. dissertations, or reports.

The second textometric analysis concerns four academic books fully dedicated to Arctic transportation that were published recently. These four books constitute our second corpus.

For these books, we therefore performed a parallel analysis. These books were included in a parallel corpus because they were published by academic editor, written exclusively by scholars, were peer reviewed and edited by authors we identified as key authors of the topic.

During the analysis of our results, as a comparison, we also performed a textometric analysis of professional press articles. Through this analysis, we were able to ascertain the convergence or divergence of concerns between academia and the business world. While the review of professional press is not, strictly speaking, commonly part of a systematic literature review, we also aimed to identify sectorial themes that are salient in professional communication and not addressed in the academic literature.

Step 3: Sample of potentially relevant literature

We conducted a keyword research on EBSCO and SCOPUS, two of the most renowned and used academic databases in order to identify a first set of academic articles dealing with our topic. We limited our research to 30 years from 1990 to 2019 included. We then performed a research in February 2020 to include the any recently published articles. Five articles were included at this stage. These two databases are complementary since only 47 articles were duplicates out of the 386 articles which composed the corpus for the review.

Following the methods of [START_REF] Mandjak | Port marketing from a multidisciplinary perspective: A systematic literature review and lexicometric analysis[END_REF] the EBSCO and SCOPUS research was performed on two axes of keywords. One for the geographical approach to studying the Arctic and a second for the maritime-related transportation in the area. In order to select the keywords, we first surveyed and listed the potential keywords. Then we contacted a group of experts, who first individually gave us their feedback. Finally, we shared feedback to reach a consensus on the keywords. For the geographical axis, we excluded Arctic Bridge and Polar as keywords and retained Arctic, Northern Sea Route (and NSR), Northeast Passage (and NEP) North West Passage (and NWP). For the transportation axis, we selected Shipping, Transport, Maritime, Port, Hinterland, Tourism, and Cruise. To verify the quality of this method, when we had the final database, we also looked at smaller scale geographical areas to check if they were present in the corpus. We looked for Svalbard (842 occurrences), Greenland (1026), Siberia (274), Nunavut (476), Alaska (591), Baffin (114), Beaufort (240), After the collection and filtering out unrelated articles, 900 articles remained from the EBSCO database (Table 2a) and 445 articles from SCOPUS database (Table 2b). Several articles, however, appeared in more than one combination of keywords. After eliminating the duplicates, 204 articles relevant to the literature review remained in the EBSCO database.

Four articles, however, were not academic articles as they were consulting reports published in an academic review (1), book chapters (1), and books (2). One article appeared in the proceedings from a renowned international conference and was highly cited as such. We first excluded the article and then discovered that the paper was published in a peer reviewed journal. We only included the peer-reviewed version in our database. We used the same methodology to select 239 articles from the SCOPUS database. We excluded articles written in French (3) as well as in Russian (1). We also excluded book chapters (2). We finally merged both corpora and found 47 duplicates. The final total of our academic literature corpus was 386 academic peer reviewed articles in English. From these 386 articles, 49% appear only with one combination of keywords, 81% appear with five or less combinations and only 10% appear with 9 or more combinations with one article appearing in 23 combinations in each database.

Figure 1: Distribution of articles of the corpus in the combinations of keywords

Descriptive bibliographic results

The corpus (Fig. 2) shows an increasing interest in the topic over time. There are less than 5 articles per year from 1990 to 2006, then an increasing trend with three peaks in 2011 ( 24), 2016 (45) and 2018 (66). Our systematic literature review harnesses the advances in textometric software. Textometric software has been used for discourse analysis in linguistics (Longhi, 2020) and other social sciences [START_REF] Ratinaud | Des mondes lexicaux aux représentations sociales. Une première approche des thématiques dans les débats à l'Assemblée nationale (1998-2014)[END_REF]. Discourse analysis, however, primarily aims at understanding language and social phenomena through the study of discourse [START_REF] Partington | Patterns and meanings in discourse: Theory and practice in corpus-assisted discourse studies[END_REF]. While not sharing the same object of study, the methods used in some types of discourse analysis, such as textometry, can be employed to enhance systematic literature reviews. Indeed, the goal of these reviews is to provide "a critical component of advancing knowledge" in a given field of study (Durach et al. 2017: 67). Because it automatizes the coding phase and a part of the interpretation phase, textometry enhances knowledge about a field of study by allowing for a larger volume and wider range of literature to be analyzed and integrated during the review process. It also allows researchers to avoid some biases during the analysis and integration phase of the review.

Given its potential, textometric analysis has recently been used in several systematic literature reviews in management sciences. [START_REF] Macke | Systematic literature review on sustainable human resource management[END_REF] use a textometric method in their literature review about sustainable human resource management (SHRM). Their research contributes to the knowledge about the evolution of research about SHRM in time.

Additionally, the authors use the textometric analysis results to build a theoretical model of SHRM in the grounded theory approach. Mandják et al. ( 2019) carry out a systematic literature review of ports research with Iramuteq. They observe that ports have long been studied in terms of their operations, but that there is a need for further development of an industrial marketing approach in the field. Textometric analysis is therefore a promising method to understand the current academic conversations about transportation and the Arctic.

In addition, it has already been used in management science studies for systematic literature reviews.

In this article, we use textometric analysis of the full text of the 386 articles and 4 books to complete the fifth step of Durach et al.'s (2017:75-76) protocol for systematic literature reviews in Supply Chain Management. In this step, [START_REF] Durach | A new paradigm for systematic literature reviews in supply chain management[END_REF] recommend that the researchers 1) "code the relevant data from primary studies" and 2) carry out the task of "summarizing or cumulating the findings of different studies" through analysis and integration. As [START_REF] Durach | A new paradigm for systematic literature reviews in supply chain management[END_REF] highlight, there are risks associated with these substeps.

In substep 5.1, variability in manual coding can introduce bias into the review. In substep 5.2, there is a risk of expectancy bias, by which researchers highlight information that conforms to their expectations. Expectancy bias may also lead them to omit problematic information. This introduces subjectivity into the analysis and integration of the different studies.

In order to minimalize these biases and to include a much larger range and volume of research about Arctic transportation, we chose to use textometry to complete step 5. In this case, the manual coding of 5.1 is replaced by statistical calculation of the salience of content words (nouns, verbs, adverbs, and adjectives), the strength of the connections between them, and the statistic relationship of the contexts in which these content words appear. This method also reduces bias in step 5.2, during the analysis and integration of the coding of the various articles. While the interpretation of the results requires the insight of the researchers, the different themes calculated by Iramuteq are salient because of their statistical strength in the corpus, and not because of the researchers' own expectations. Finally, as textometry analyses the corpus of articles as a whole, it meets the goals of steps 5.1 and 5.2 as defined by Durach et al. (2017: 75): 5.1) discover the "content and interrelationships" between the information in the different articles and 5.2) "develop narrative propositions" that integrate "insights from different methodological approaches and research settings."

Iramuteq: underlying theory and types analyses performed

Textometric software programs allow researchers to carry out statistical analyses on content words in a corpus. Simply put, the hypothesis underlying Iramuteq, and textometry in general, is that the frequency with which a content word appears, the statistical relationships between content words and their contexts all witness to thematic patterns specific to a corpus. These patterns occur at a local level when content words are repeatedly used closely together. They also occur at a more global level when the same content words occur in the same contexts throughout the corpus. These latter trends the corpus form what Reinert calls "lexical worlds" (1990). [START_REF] Reinert | Les «mondes lexicaux» et leur «logique» à travers l'analyse statistique d'un corpus de récits de cauchemars[END_REF] explains that these represent cognitive "common places" towards which the authors of a corpus tend to gravitate.

The interest of this method for a systematic literature review is therefore threefold. First, the method provides a statistically grounded representation the current academic conversations in a given research field. Second, it also represents how these different conversations interlace or remain isolated from each other. The analyses were carried out in the five steps. We describe these five steps in following paragraphs.

First, the software lemmatizes content words such as nouns, verbs, adjectives and adverbs.

This means that grammatical information, such as the plural or verb tense, is removed from the corpus. For example, the words girl and girls are counted as two occurrences of one active form, girl. In the same way, the verbs ran and run are counted as two occurrences of one active form, run.

Second, the software divides the corpus into segments. These segments become the basic unit of context used in the statistical analyses. In our analysis, we chose the segment length of 26 words, as this corresponds to the average length of a sentence in English academic articles [START_REF] Deveci | Sentence Length in Education Research Articles: A Comparison between Anglophone and Turkish Authors[END_REF].

Third, the software performs a basic statistical analysis that calculates the following information. First, the number of texts in the corpus. Second, the number of words in the corpus. Third, the number of active forms in the corpus. Fourth, the number of hapaxes in the corpus. Fifth, the mean number of words per text. In addition, at this step, the software creates four tables:

1) active forms, ranked from most frequent to less frequent;

2) supplementary forms that include grammatical words such as a, the, and for. These forms are not counted in the active forms category;

3) hapaxes that include words that occur only once in the corpus; 4) total that includes both active forms and supplementary forms.

Fourth, a similarity analysis performed by Iramuteq. It is based on graph theory [START_REF] Flament | L'analyse de similitude[END_REF]. It creates a graph using the co-occurences of forms in the segments and the strength of their association [START_REF] Longhi | Chapitre 9. Tweets politiques: Corrélation entre forme linguistique et information véhiculée[END_REF]. This graph, therefore, represents the local connections that authors make between forms, and therefore, concepts, used to speak about Arctic transportation. Details about graph theory and the similarity analysis algorithm used in Iramuteq are given in [START_REF] Marchand | L'analyse de similitude appliquée aux corpus textuels: Les primaires socialistes pour l'élection présidentielle française (septembre-octobre 2011)[END_REF].

Fifth, the software performs the Reinert analysis. Details about the algorithm can be found in [START_REF] Reinert | Une méthode de classification descendante hiérarchique: Application à l'analyse lexicale par contexte[END_REF][START_REF] Reinert | Présentation du logiciel Alceste à l'aide d'un exemple[END_REF][START_REF] Reinert | Proposition d'une méthodologie d'analyse des données séquentielles[END_REF] in addition to [START_REF] Ratinaud | Amélioration de la précision et de la vitesse de l'algorithme de classification de la méthode Reinert dans IRaMuTeQ[END_REF] and [START_REF] Ratinaud | Application de la méthode ALCESTE à de "gros" corpus et stabilité des "mondes lexicaux" : analyse du[END_REF]. The Reinert analysis is a type of Descending Hierarchical Classification (DHC). It is based on a correspondence analysis. Using the frequency tables created at the lemmatization stage (step 1) and the segments into which the text was initially divided (step 2), the algorithm repeatedly divides the corpus into homogenous sections according to the chi-squared correlation between the categories and the frequency with which the active forms appear in similar segments [START_REF] Bart | L'analyse de données textuelles avec le logiciel Alceste[END_REF]. This creates different categories or "lexical worlds" according to [START_REF] Reinert | Alceste une méthodologie d'analyse des données textuelles et une application: Aurelia De Gerard De Nerval[END_REF]. It is important to underline that the categories created by the Reinert analysis are composed of the texts of the complete corpus. In this way, the categories exist in the entire literature of Arctic transportation as it is represented by the corpus. In addition to the Reinert dendrogram, Iramuteq creates a graph of the correspondence analysis representing the two factors that best explain the distribution of the corpus as axes.

We followed the above procedure for the analyses of the corpus of four books and the corpus of professional press that we describe in section 3.5.

Results of the textometric analysis

Results concerning the frequency of the active forms

As explained above, the analysis in this study was performed on the full text of 386 articles.

These articles amount for 2,663,095 occurrences of the forms. Consequently, there is an average of 6899 forms per article, which is consistent with results obtained is similar textometric literature reviews (see for example [START_REF] Mandjak | Port marketing from a multidisciplinary perspective: A systematic literature review and lexicometric analysis[END_REF]. 44,995 different forms generate these occurrences, of which, 20,983 are hapaxes (0.79% of occurrences for 46.63% of forms). 489 forms were supplementary forms. 44,525 active forms, therefore, were included in the analysis.

We now can divide the corpus into five groups:

• Group 1: the word Arctic represents 1.63% of occurrences of forms in the whole corpus, confirming its central position in our study. It represents 1.62% in EBSCO only papers, which shows high consistency in the corpus.

• Group 2: five more forms, state, ship, sea, ice and international, together with Arctic, represent 0.013% of the different forms of the corpus, but 5.23 % of the total occurrences in the corpus.

• Group 3: fifteen more forms, route, area, region, vessel, water, development, nsr, cost, law, include, time, port, russian, new, increase, and oil represent together with the previous five forms 10.12% of the corpus's occurrences.

• Group 4: 47 more forms represent, with the previous forms, 20% of the occurrences.

• Groupe 5: 106 more forms represent, with the previous forms, one-third of the occurrences.

• Group 6: the rest of the forms (99.6%) represent two-thirds of the corpus.

The concentration of forms in the occurrences shows the consistency of our corpus since the authors of the 386 articles use the same vocabulary to discuss Arctic transportation. Fig. 3 shows the logarithmic distribution of active forms in the overall corpus. Concerning the keywords used to select articles for the corpus, not all of them are present in the top occurrences of active forms in the corpus itself. This confirms that the authors whose articles were included are mainly concerned with shipping and ports along the Northern Sea Route.

Similarity analysis

We performed the similarity analysis on the Group 2, Group 3 and Group 4 of words. We did not include Group 1 which is composed of Arctic, because the centrality of this concept masked other connections. Secondary connections appear more clearly without Group 1. In addition, we did not include Group 5 in order to focus on the 0.15% of forms that represent 20% of the corpus occurrences, i.e., the heart of the corpus. Then, we performed the similarity analysis without the form ship that was too central on to part of the graph.

Figure 4a: Similarity analysis of the corpus (Groups 2, 3 and 4)

Figure 4a shows the results of the similarity analysis, with ten clusters of interrelated forms. shows an opposition between the state cluster and sea cluster. Each of them is linked to other clusters. These two main clusters and linked clusters include:

1) the concept of sea, which attracts a geographical cluster (area, north, ocean, route, polar, water, Canadian, etc.) with also marine environment branch, and concepts of government and convention; then minor clusters related are:

a. the concept of route, which starts inside the main sea cluster then opens to several branches which are transport, passage, transit; then nsr and service, and then port, cost and time;

b. the concept of ice, related to sea through new and that splits toward several small branches. These include ice vessel, ice base, ice condition, and then a group of forms around model, system, increase, risk and result.

c. the concept of region activity. This concept evolves toward oil company, economic development, resource and tourism with cruise and community

2) The concept of state with names of countries (Canada, Russia, country), institutional words (policy, agreement, border, council, etc.), a few other words concerning the role of state (unite, provide, include, develop, well), and case study. ; then minor clusters related are:

a. the concept international with international strait, international law and maritime b. the linear concept of environmental impact climate change.

Figure 4b: Similarity analysis of the corpus (Groups 2, 3 and 4 without ship)

Reinert analysis

To avoid bias, the categories of dendrogram and the axes of the factorial analysis were named using an iterative method, as described by [START_REF] Mandjak | Port marketing from a multidisciplinary perspective: A systematic literature review and lexicometric analysis[END_REF]. A linguist and a port economist first named the categories separately. In a second step, they compared their results and reached a consensus about the categories' names.

The dendrogram (Figure 5) shows two meta categories with each four categories. The categories of the first meta category deal with governance. The categories of the second meta category are related to Arctic operations.

• Category 1 is legal governance with semantic fields of law (convention, claim, treaty, right, etc.) and territories (state, coastal, delimitation, territorial, etc.).

• Category 2 is tourism governance with semantic fields of cruise (tourist, tour, operator, visitor, cruiser, expedition…) and the local governance (resident, community, attitude, Nunavut, wildlife…)

• Category 3 is outsider's geopolitics governance with semantic fields of disputes (military, war, nato…) the Asian countries (China, Chinese, Korean, Japan, official, …) the E.U. (E.U., European, Union, …)

• Category 4 is political governance with semantic fields of sustainable development (social, environment, resource, develop, governance…), and policy (government, political, institution, region, strategy…).

• Category 5 is ice conditions for operations with semantic fields of conditions (temperature, thickness, concentration, melt, cover, multilayer, surface, wind, sea, average…) and seasonality (season, summer, winter, warm…)

• Category 6 is modelization of operation factors with semantic fields of risk (probability, collision, accident, etc.) and the field of modeling (datum, variable, parameter, simulation, method, result, distribution, algorithm).

• Category 7 is shipping routes of operation with semantic fields of shipping (teu, container, vessel, route, ship, fuel, cost, fee, insurance, etc.) and the field of routes (nsr, suez, canal, transit, icebreaker, panama, …).

• Category 8 is Arctic trade operations with semantic fields of market (gas, lng, oil, million, ton, cargo, ore, volume, freight, etc.) and the field of logistics (export, import, transport, port, shipment, east, Europe, etc.). issues. This means that on the governance side, from management to modelization (bottom to top) there is an evolution from the cruiser's experience and marketing toward local communities management (category 2), then political issues (category 4) and geopolitical issues (category 3) and at last legal frameworks and international conventions (category 1) that are legal models. On the operation side, from management to modelization (bottom to top), there is an evolution from tourist management (Category 2), to the market (category 8), to factors of operations (category 6) and ice conditions (category 5) toward international routing (category 7) that is a model of shipping operations.

This interpretation opens an interesting perspective. The top of Figure 6 is much more densely filled than the bottom. Apparently, there is more research done on modelization than on management of arctic issues. Statistically, management appears in Group 6 of active forms, thus not a salient active form in the corpus. In Figure 6, the governance side is filled with forms from the tourism category (Marketing Management) and with political and geopolitical forms. On the operation side, however, there are only a few forms. Some of them are marketing concepts like service and value or refer to specific areas of logistic management like information management.

In addition to this first observation, there is a large gap between legal models and economic models. There is a gap around the top middle of Figure 6 between x=-1 and x=1 and y=0 and y=2. We interpret this gap as being the modelization of risk, which is conceptually between operations and governance/compliance. Risk is also an active form that is present in the corpus, but again, it is not among the most frequent forms.

Figure 6: graphic representation of the corpus's correspondence analysis

Comparative analysis of recently published books on Arctic shipping

In the past five years, there has been an increase in research on Arctic shipping (see Figure 2)

and four academic books have been published in English on Arctic issues (Table 5). These books included works by leading scholars and were also edited by top scholars identified in our literature review.

Comparative analysis with professional press

In order to compare the state of research with the realities of the field, we carried out a similar textometric analysis on professional press dedicated to Arctic transportation systems. In order to do this, we contacted experts of the field and asked them about the main professional press for Arctic transportation in English. They agreed on two titles: The Independent Barents

Observer, and GCaptain. The former is specialized about the topic while the latter is more general geographically. We included all articles of the former that were available online and selected articles from the latter with the keywords used to select the academic articles.

The Reinert analysis of this professional press corpus provides us with 10 categories that can be grouped into three meta-categories (NSR, Climatology, Geopolitics) as Figure 8 shows.

From these results, we can underline that professional press in logistics covers a wider range of topics than the academic articles. The density of the graphical representation of the correspondence analysis (Figure 9) confirms this observation. Importantly, we can observe that there are areas of research that academics should deepen. We can identify three such domains. First, there is the logistics of access to the Arctic routes. These different types of logistics include hinterland access for markets (Category 6), for logistics of people (Category 8), including researchers and emerging tourists, and for logistics of resources (Category 5).

Second, Category 5 clearly shows the link between fossil fuel extraction projects and shipping in the Arctic, as well as previously mentioned access to hinterland. Research focusing on these structuring projects (i.e. Yamal, Sabetta, Murmansk, etc.) needs to be developed. Third, Category 9 shows active forms that rarely appeared in the academic literature review such as icebreaker, construction, vessel class, etc. There is a wide field of research to develop in order to be in phase with these industry concerns.

Research Findings and Implications

The results presented in the study enable us to provide clear answers to our three research questions.

• QR1: what is the state of the art considering Arctic transportation?

First, there is a large body of research on the topic, with 386 articles found and studied. This is comparable to similar studies on port marketing with 369 articles over 40 years on a major and worldwide topic [START_REF] Mandjak | Port marketing from a multidisciplinary perspective: A systematic literature review and lexicometric analysis[END_REF]. Moreover, research about Arctic transportation is experiencing a growing trend. There are leading scholars in the field who work together in collaborations. Some of them collaborated to deepen the topic through recently published academic books.

In terms of content, the research on Arctic transportation systems covers the three pillars of sustainable development. Environmental issues are addressed, especially greenhouse gas emissions. Social issues are also treated, from both the legal aspects of compliance, international negotiations, or conventions, and the consequences of development of shipping and trade in the Arctic on local people.

Of course, trade development and economic issues for the industry are also at the heart of the concerns of scholars in the field. There is a concentration on economics of the shipping routes, compared to other options as well as on how climatic conditions influence feasibility.

Port strategy and industrial clusters are also identified as emerging topics. We notice a larger number of papers on the NSR than on the NWP.

• QR2: does academic research on Arctic transportation match professional concerns on the topic?

Professional concerns, summarized in our study by two of the main press journals on the field, match well with academic research. This means scholars are close to field issues that professionals find important. For this reason, researchers probably provide answers to professional issues. However, we observe a few topics that are not covered in depth by scholars. These could be developed in further research. The professional press also covers the topic from two perspectives that are different from scholars' concerns: climate change research and geopolitical and military issues. These two aspects are included in some research papers we studied, but they are not the core of the papers.

• QR3: what are the perspectives of future research in the field?

From the textometric analysis of the academic literature on Arctic transportation, the recently published books and the comparison with professionals' concerns, we identified five subfields of research to develop in the future. These fields are the following:

o The first major area to be developed in research on Arctic transportation systems is management. There is research on governance as well as on operation, but there is a gap in between these two aspects that corresponds to the management issues. What is at stake on tactical and strategic levels for companies? What are the marketing, corporate strategy, business models associated with this emerging market for logistics? What are the management constraints in the specific conditions of Arctic region?

o The second area is risk management. There are only a few studies that mention risk while this appears to be a wide area to explore once we know what the issues are, the legal context and the constraints on business. Risk and compliance to rules are important stakes. This area is also related to management since risk management in the Arctic deals with environmental issues, technical and industrial issues, but also with the management of human resources.

o The third area concerns access to the shipping routes of the Arctic. This concern is a wider topic than just the hinterland. Systems of transportation to access the ports of the Arctic as well as feedering routes are mentioned in the corpus from an outside the Arctic perspective with ports in China or in the North Range. There are a few articles dealing with developments of railroads, routes, or even barges and dry ports.

o The fourth area is related to the previous one with a large representation in the press of the logistic and industrial projects in the Arctic region. Only the Yamal project is mentioned several times in our academic corpus. There are, however, other projects. In addition, there could be studies do on the feasibility, profitability of such projects as well as decision models or best practices linked to such projects. This is also true from a supply chain management, business-to-business and business network perspective.

o The fifth area concerns vessel management. The fleet of ice class vessels is specific and needs not only technical research but also organizational research.

Indeed, icebreakers figure importantly in the professional press, but this concept does not appear frequently in academic research. Specifically, professional press articles mention the influence of vessels on location of ports as well as the mix in the fleet and the transshipment constraints it imposes on operations. Lasserre and Faury (2019) also mention this aspect.

Conclusion

The textometric approach of the literature review allowed us to have a systematic overview of 386 academic articles dealing with Arctic transportation systems. These articles were selected using keywords that refer to the geography of the Arctic and maritime-related transportation in the Arctic. We were also able to compare this corpus of articles with corpora of recently published books on this topical issue and with a sample of the professional press. Such comparison helps us to answer our research questions on the state of research on Arctic transportation system, on this state in comparison with professional concerns and therefore to identify research areas to develop in the future.

Five areas are recommended for further research: 1) a management approach to Arctic transportation in addition to the legal, economic and geopolitical ones; 2) a risk management approach that deals, in particular, with conditions of operations for people, organizations, and also the consequences for the environment; 3) a logistics approach to the access to the Arctic routes, including transportation modes and dry ports; 4) an approach that studies the clustering projects in the Arctic area; 5) research on fleet management.

Our research is based on an innovative method using textometric software that allows for a systematic literature review of 386 articles, representing a large volume and wide breadth of literature related to Arctic transportation. There are, however, certain limits. Iramuteq cannot analyze a corpus with more than one language. For this reason, literature in French and Russian could not be included. Finally, while the software is able to show crucial statistical connections across articles, it may miss finer connections and argument development contained in individual articles.

  Fig. 2 confirms the topicality of Arctic transportation and the relevance of a first systematic state of the art.

Figure 2 :

 2 Figure 2: Distribution of articles of the corpus over time

Figure 3 :

 3 Figure 3: Distribution of forms in the corpus

Four

  clusters are multibranches linked to sea, state, international and ship. The cluster centered on ship is linked to six linear clusters: region development, marine development, cruise tourism, Canadian government, impact climate change, and case study. When we exclude the form ship, in order to analyze other relationships between concepts, Figure 4b

Figure 5 :

 5 Figure 5: dendrogram of the corpus Reinert analysis Figure 6 shows a correspondence analysis of the eight categories. They are represented on two axes. Next to the center of the two axes, we find the word arctic. This representation confirms the distinction between the two branches of the dendrogram. The horizontal axis divides the corpus from operations to governance in the Arctic. We interpret the second axis as ontological, in the sense that it refers to the levels of abstractions: one side (top) represents the modelization of issues in the Arctic, while the other represents the management of these

Figure 7 :

 7 Figure 7: graphic representations of the books' correspondence analysis

Figure 8 :

 8 Figure 8: dendrogram of the press correspondence analysis

Table 2a :

 2a Matrix of articles collected and selected from EBSCO

	Keywords	Arctic	NEP	NSR	NWP	Sum
	Cruise	18	9	9	13	49
	Hinterland	4	2	3	1	10
	Maritime	99	30	67	32	228
	Port	49	17	31	23	120
	Shipping	124	34	61	32	251
	Tourism	33	8	7	12	60
	Transport	81	25	52	24	182
	Sum	408	125	230	137	900

Table 2b :

 2b Matrix of articles collected and selected from SCOPUS

	Keywords	Arctic	NEP	NSR	NWP	Sum
	Cruise	21		2		23
	Hinterland	2		2		4
	Maritime	82	1	30		113
	Port	26		13		39
	Shipping	100	1	58	7	166
	Tourism	21		1		22
	Transport	52		26		78
	Sum	304	2	132	7	445

Table 3

 3

shows the most well-represented journals in the corpus. We can see that only journals cited at least two times in the corpus are presented in Table

3

. There is a total of 181 different journals that appear in the corpus. The 12 most represented journals amount for more than a third of the publications on Arctic transportation systems. Moreover, 26 journals, including 1 Transportation Research Part A: Policy and Practice, represent 50% of the publications.

2

Table 3 :

 3 Most represented journals in the corpusTable4presents the authors who are most represented in the corpus with their country of 2 affiliation. We can see that only the 23 authors who appear at least three times in the corpus 3 are presented in Table4. These authors are central to the topic and represent 10.7 % of the The most prolific country is Canada with 3 authors in the top 24 authors. The 3 authors are

	3
	Academic Journal	Number Articles	Share Sum
	Ocean Development and International Law	36	9%	9%
	Review of European, Comparative and International Environmental Law	18	5%	14%
	Maritime Policy and Management	17	4%	18%
	Problems of Economic Transition	16	4%	23%
	Journal of Transport Geography		2%	25%
	International Affairs		2%	27%
	Ocean Engineering		2%	28%
	WMU Journal of Maritime Affairs		2%	30%
	Coastal Management		2%	32%
	Environmental science and technology		2%	33%
	Europe-Asia Studies		2%	35%
	Maritime Economics and Logistics		2%	37%
	Tourism in Marine Environments		1%	38%
	Transportation Research Part A: Policy and Practice		1%	39%
	Current Issues in Tourism		1%	40%
	Journal of Sustainable Tourism		1%	41%
	Nordic Journal of International Law		1%	42%
	Resources		1%	43%
	Scandinavian Journal of Hospitality and Tourism		1%	44%
	Strategic Analysis		1%	45%
	Ambio		1%	46%
	Energy Research and Social Science		1%	47%
	International Journal of Shipping and Transport Logistics		1%	48%
	J. Mar. L. and Com.		1%	48%
	Journal of Borderlands Studies		1%	49%
	Journal of Cleaner Production		1%	50%
	Journal of Marine Science and Application		1%	51%
	Mirovaya ekonomika i mezhdunarodnye otnosheniya		1%	52%
	Polar Record		1%	52%
	Ship technology research		1%	53%
	Studies on Russian Economic Development		1%	54%
	The RUSI Journal		1%	55%
	Transportation Research Part D: Transport and Environment		1%	55%
	Transportation research record		1%	56%
	American University International Law Review		1%	57%
	Annals of Tourism Research		1%	57%
	Applied Ocean Research		1%	58%
	Case W. Res. J. Int'l L.		1%	58%
	Climatic Change		1%	59%
	Energy Policy		1%	59%
	Eurasian Geography and Economics		1%	60%
	European Foreign Affairs Review		1%	60%
	FOCUS on Geography		1%	61%
	INCAS Bulletin		1%	61%
	International Environmental Agreements: Politics		1%	62%
	International Journal of Offshore and Polar Engineering		1%	62%
	Journal of International Affairs		1%	63%
	Marine Policy		1%	63%
	Nature Climate Change		1%	64%
	Polar Research		1%	65%
	Science of The Total Environment		1%	65%

6 8 appears second in terms of cumulated publications (17) from these major authors (4 out of 9 24). Other non Arctic countries such as China (2 authors) and Singapore (2 authors who have 10 more than 3 articles) are also represented.

11

Table 4 :

 4 Most active authors in the field of Arctic transportation

	12
	Authors	Nbr of Publications	Country of affiliation
	Lasserre, F.	9	Canada
	Dawson, J.	7	Canada
	Faury, O.	6	France
	Bennett, M.M.	5	Hong Kong
	Khan, F.	5	Canada
	Cariou, P.	4	France
	Cheaitou, A.	4	France
	Ehlers, S.	4	Germany
	Smith, L.C.	4	U.S.A.
	Stephenson, S.R.	4	U.S.A.
	Stewart, E.J.	4	New Zealand
	Zhang, Y.	4	Singapore
	Berkman, P.A.	3	U.S.A.
	Brubaker, R.D.	3	Norway
	Chen, J.S.	3	U.S.A.
	Erikstad, S.O.	3	Norway
	Fedi, L.	3	France
	Furuichi, M.	3	Japan
	Hu, H.	3	China
	Meng, Q.	3	Singapore
	Moe, A.	3	Norway
	Stokke, O.S.	3	Norway
	Tarovik, O.V.	3	Russia
	Yan, X.	3	China

13 2.4. Textometric analysis procedure: textometric analysis with Iramuteq 14 2.4.1. Textometry as a method in systematic literature reviews 15

Table 5 :

 5 Ranking of active forms in the corpus according to frequency of occurrence

	Form	Rank
	Arctic	1
	Shipping	2
	NSR	13
	Port	18
	Maritime	31
	Transport	27
	Tourism	34
	Cruise	45
	NWP	659
	NEP	1093
	Hinterland	2253

Table 5 :

 5 corpus of academic books

	Authors	Year	Title	Editor
	Keupp	2015	The Northern Sea Route. A Comprehensive Analysis	Springer
	Pastusiak	2016	The Northern Sea Route as a Shipping Lane. Expectations and Reality	Springer
	Vestergaard, Kaiser,	2018	Arctic Marine Resource Governance and	Springer

We carried out the same analyses as we did for the corpus of 386 academic articles.

The Reinert analysis results in six categories for Keupp's book and only four for the three other books (see Table 6 and details in Figure 7). For all the books, these categories are spread in three groups on the two axes of the correspondance analysis graph (Figure 7). We first observe that the categories of these books cover all the categories of our main corpus of academic articles, except for Tourism. Second, we observe that in all four books, there are categories dealing with the maritime transport aspect (trade, operations and shipping; routes and vessels; infrastructures and business; and transport geography and trade ports). Moreover, three categories are often together in the graphic representation. There is therefore a comparable architecture of topics. In addition, all the graphic representations have a propeller-like shape (see Figure 7). What is interesting is the central form for most books in these representations is sea. In opposition, we do not identify the lexical field of land transport. We interpret the propeller shape with categories going from the center to develop outside as the community's push to move research toward developing themes.


M.D Lionel Athlani
email: lionel.athlani@gmail.com

Ph. Audrey Chenel
email: achenel@newcliptechnics.com

Philippe Berton
email: pberton@newcliptechnics.com

M.D Romain Detammaecker
email: romain.detammaecker@hotmail.fr

Gilles Dautel
email: gillesdautel@mac.com

M.D Ph.D Dautel Gilles

Three-Dimensional Versus Radiographic Measurements for Analyzing Extra-Articular Distal Radius Malunion

Keywords: 3D, Computer-assisted preoperative planning, Corrective osteotomy, Distal radius malunion

de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

INTRODUCTION

Patients with symptomatic distal radius malunion are candidates for corrective osteotomy surgery. The deformity is typically evaluated using plain radiographs (1-3) and the differences in palmar tilt, radial tilt, and ulnar variance between the normal and affected sides have been used to determine the amount of deformity correction required [START_REF] Gray | Image-Based Comparison Between the Bilateral Symmetry of the Distal Radii Through Established Measures[END_REF][START_REF] Hollevoet | Comparison of palmar tilt, radial inclination and ulnar variance in left and right wrists[END_REF][START_REF] Campe | Corrective osteotomies in malunions of the distal radius: do we get what we planned?[END_REF]. However, distal radius malunion is considered a three-dimensional (3D) deformity and pre-operative planning based on plain radiographs may not be sufficiently accurate to ensure anatomical correction [START_REF] Athwal | Computer-assisted distal radius osteotomy[END_REF][START_REF] Bilic | Osteotomy for deformity of the radius. Computer-assisted three-dimensional modelling[END_REF][START_REF] Jupiter | Computer-generated bone models in the planning of osteotomy of multidirectional distal radius malunions[END_REF][START_REF] Miyake | Three-dimensional deformity analysis of malunited distal radius fractures and their influence on wrist and forearm motion[END_REF].

Prommersberger et al. [START_REF] Prommersberger | Outcome after corrective osteotomy for malunited fractures of the distal end of the radius[END_REF] and Von Campe et al. [START_REF] Campe | Corrective osteotomies in malunions of the distal radius: do we get what we planned?[END_REF] have shown that residual deformity is present in more than 50% of cases and that it negatively affects the functional outcome .

Recently, 3D bone models created from computed tomography (CT) data have been used to quantify the deformity [START_REF] Oka | Corrective osteotomy using customized hydroxyapatite implants prepared by preoperative computer simulation[END_REF][START_REF] Miyake | Comparison of three dimensional and radiographic measurements in the analysis of distal radius malunion[END_REF]. Using 3D models, Gray et al. [START_REF] Gray | Image-Based Comparison Between the Bilateral Symmetry of the Distal Radii Through Established Measures[END_REF] found that the contralateral radius can be used to define normal anatomy and serve as a reference during preoperative planning for malunion surgery. In a multicenter study, Buijze et al. [START_REF] Buijze | Three-Dimensional Compared with Two-Dimensional Preoperative Planning of Corrective Osteotomy for Extra-Articular Distal Radial Malunion: A Multicenter Randomized Controlled Trial[END_REF] compared the results of corrective osteotomy for extra-articular distal radial malunion performed with 3D versus twodimensional (2D) preoperative planning. They found no clinical differences between the two groups of patients. Nevertheless, radiographic analysis showed significant differences in the average residual palmar tilt and radial tilt compared with the healthy contralateral side, in favor of 3D method. The purpose of this study was to compare the accuracy of evaluating the deformity in distal radius malunions using plain radiographic measurements versus a threedimensional (3D) method involving 3D computer bone models.

METHODS

Study population

Between December 2016 and March 2019, consecutive patients who had an extra-articular distal radius malunion were included after they provided informed consent and institutional review board approval was obtained. Initially, all patients had sustained an extra-articular fracture treated by cast immobilization. These patients had been referred to us because of wrist pain, deformity, and/or limited pronation-supination. They had not previously undergone surgery. Standard (posteroanterior and lateral) radiographs and low-dose CT scans (Aquilion ONE; Canon Medical Systems, Otawara, Japan) of both wrists including the forearms were made for each patient.

Radiographic evaluation

Palmar tilt (accuracy of 1°), radial tilt (accuracy of 1°), and ulnar variance (accuracy of 0.1 mm) were measured (Figure 1) by a single independent examiner (senior surgeon). The "normal" status of the contralateral wrist was always confirmed. Digital images were viewed on OsiriX © (Pixmeo ® 2016, Geneva, Switzerland).

3D evaluation

The CT scan data were sent to a workstation in standard DICOM format. The 3D bone surface models of the radius were created using Simpleware software (Synopsys Inc, Mountain View, CA, USA) provided by **Blinded by JHS** Newclip Technics. The locations of the relevant points and axes were determined on the 3D bone surface models by a single engineer specialized in biomechanics who was blinded to the radiography findings. For the affected and contralateral wrists, the 3D palmar tilt (accuracy of 1°), 3D radial tilt (accuracy of 1°) and 3D ulnar variance (accuracy of 0.1 mm) were calculated based on these points using computer-aided design software (3D Creo Parametric®, PTC, Boston, USA) (Figure 2). The radial styloid and midway points were defined to minimize the impact of the sagittal plane deformity when calculating 3D radial tilt and 3D ulnar variance.

The amount of deformity was defined for the three 3D measurements as the difference between the two sides in the coronal and sagittal planes. The axial rotational deformity was analyzed by superimposing the 3D image of the affected radius onto the 3D mirror image of the contralateral normal radius. Then, we evaluated the magnitude of the axial rotational deformity by calculating the difference-in degrees (accuracy of 1°)-between the two axial planes defined for the two images superimposed proximally to distally (Figure 3).

Statistical analysis

For the two subgroups, the mean values and ranges were calculated. Differences between the radiographic and 3D methods were assessed using Student's t-test. Correlations between two continuous variables were investigated using Pearson's correlation coefficient (r) and simple regression analysis. Data were deemed significant if p values were less than 0.05.

RESULTS

Patients

Thirteen patients (5 men, 8 women) with a mean age of 40 years (22-57) were included. The dominant upper limb was involved in 5 cases. The average interval between the fracture event and our examination was 5 months (range 3-10). The 13 patients were divided into two subgroups based on their sagittal deformity: dorsal deformity type (malunion with dorsal tilt, n=7) or palmar deformity type (malunion with palmar tilt, n=6). The results for each patient are presented in Table 1.

Palmar tilt comparison

In the dorsal deformity group, the average palmar tilt on plain radiographs of the affected wrists was -19° (range -5° to -42°), whereas that of the contralateral normal wrist was +8° (range +5° to +12°). On the 3D models, the average 3D palmar tilt was -18° (range -2° to -39°) and +8° (range +4° to +12°), respectively.

In the palmar deformity group, the average palmar tilt on plain radiographs of the affected wrists was +29° (range +16° to +39°), whereas that of the contralateral normal wrist was +9° (range +5° to +11°). On the 3D models, the average 3D palmar tilt was +27° (range +19° to +37°) and +8° (range +4° to +12°), respectively.

In the both groups, the 3D palmar tilt was positively correlated with the radiographic palmar tilt (dorsal deformity group: r = 0.98, p = 0.59; palmar deformity group: r = 0.95, p = 0.19). The 3D palmar tilt had a smaller value than the radiographic palmar tilt (dorsal deformity group: y = 0.9498x + 0.4; palmar deformity group: y = 0.811x -3.8). The quantitative difference between the 3D method and plain radiographs was on average 2° for the dorsal deformity group and 3° for the palmar deformity group. ).

Radial tilt comparison

In the dorsal deformity group, the average radial tilt on plain radiographs of the affected wrists was 13° (range 5° to 15°), whereas that of the contralateral normal wrist was 23° (range 18° to 26°). On the 3D models, the average 3D radial tilt was 12° (range 2° to 19°) and 22° (range 18° to 25°), respectively.

In the palmar deformity group, the average radial tilt on plain radiographs of the affected wrists was 21° (range 14° to 29°), whereas that of the contralateral normal wrist was 22° (range 18° to 25°). On the 3D models, the average 3D radial tilt was 19° (range 10° to 26°) and 22° (range 19° to 26°), respectively. The 3D radial tilt was positively correlated with the radiographic radial tilt (dorsal deformity group: r = 0.84, p = 0.42; palmar deformity group: r = 0.91, p = 0.12). However, the quantitative difference between the 3D method and plain radiographs was 3° on average for both groups.

Ulnar variance comparison

In the dorsal deformity group, the average ulnar variance on plain radiographs of the affected wrists was +1.9 mm (range -1.5 to +4 mm), whereas that of the contralateral normal wrist was -0.7 mm (range -2 to 0 mm). On the 3D models, the average 3D ulnar variance was +3.2 mm (range -0.7 to 5.5 mm) and -0.5 mm (range -2 to 0mm), respectively.

In the palmar deformity group, the average ulnar variance on plain radiographs of the affected wrists was +1.3 mm (range -1 to 3 mm), whereas that of the contralateral normal wrist was (range -0.1 to 4.2 mm) and -1.1 mm (range -2 to 0 mm), respectively. The 3D ulnar variance was positively correlated with the values on radiographs (dorsal deformity group: r = 0.98, p = 0.002; palmar deformity group: r = 0.97, p = 0.007). Both groups had a significant difference in the average 3D and radiographic ulnar variance with the 3D measurements being consistently higher . The difference was on average +1.3 mm for the dorsal deformity group (p = 0.002) and +0.6 mm for the palmar deformity group (p = 0.007).

Axial rotational deformity

The average axial rotational deformity was 9° (range 2 to 21°). It was 5° (range 2 to 12°) in the dorsal deformity group and 13° (range 2 to 21°) in the palmar deformity group.

DISCUSSION

The current study shows that the three 3D parameters describing the deformity in extraarticular distal radius malunions are positively correlated with those measured on radiographs. Moreover, we found that, in most cases, the values of palmar tilt, radial tilt and ulnar variance derived from 3D bone models differed only slightly from those derived from radiographs. However, on average, the 3D palmar tilt and 3D radial tilt were smaller than in the radiographic evaluation. Conversely, the 3D ulnar variance values were larger.. According to Von Campe A et al. [START_REF] Campe | Corrective osteotomies in malunions of the distal radius: do we get what we planned?[END_REF], after corrective osteotomy using preoperative planning with plain radiographs, a residual deformity of more 10° with under-correction of the palmar tilt and overcorrection of the radial tilt deformity is often found. This may be the result of inadequate pre-operative analysis of those two values. On radiographs, the distal radius is seen in a 2D projected view. As the distal radius tilts more dorsally or more ventrally, the radial margin of the distal radial articular surface moves more proximally or more distally, and the angle changes [START_REF] Walenkamp | Computer-assisted 3D planned corrective osteotomies in eight malunited radius fractures[END_REF]. Therefore, one of the potential advantages of virtual preoperative planning would be the possibility of simulating the change in radial tilt after the dorsal or palmar tilt deformity has been corrected. . Ulnar variance is an important parameter for assessing shortening [START_REF] Prommersberger | Outcome after corrective osteotomy for malunited fractures of the distal end of the radius[END_REF][START_REF] Campe | Corrective osteotomies in malunions of the distal radius: do we get what we planned?[END_REF]. Therefore, we used the ulnar margin of the volar rim of the radial articular surface as a measuring point for ulnar variance on the radiographic evaluations. This point is not usable in 3D models because the sagittal deformity of the distal radius causes a measurement error. As a result, we used a point midway between the volar and dorsal rims of the ulnar margin of the radial articular surface as a reference point. In our study, ulnar variance was the only parameter with a significant difference between the 3D and 2D analysis. The 3D method found higher values while remaining quantitatively slightly different from those of the radiographic evaluation. This difference could be explained by the use of a "midway" point on 3D models. However, the use of the ulnar margin of the volar rim of the radial articular surface on radiographs could underestimate the magnitude of the shortening deformity, especially in cases of severe sagittal deformity. Von Campe et al. [START_REF] Campe | Corrective osteotomies in malunions of the distal radius: do we get what we planned?[END_REF] noted that more 40% of patients had a residual shortening deformity of ≥ 1 mm after a surgical procedure in which the pre-operative planning was done with radiographs. Ulnar variance improves spontaneously after the sagittal and coronal plane deformities are corrected, without lengthening [START_REF] Piñal | Sagittal rotational malunions of the distal radius: the role of pure derotational osteotomy[END_REF]. Thereby, 3D analysis could be helpful for evaluating the relationship between the correction of palmar tilt, radial tilt and ulnar variance.. Since the axial rotational deformity cannot be detected radiographically, its extent cannot be quantified. We believe our 3D method allows the axial rotational deformity to be evaluated relative to the contralateral normal radius, which is the rotation reference for a given patient.

However, in this study, we could not conclude that the axial rotational deformity is correlated with the differences between the radiographic and 3D evaluations. Lee et al. [START_REF] Lee | Correlation of malrotation deformity in distal radius fractures with radiographic analysis: cadaveric study[END_REF] found this deformity probably does not affect the radiographic parameters (palmar tilt, radial tilt and ulnar variance). For Shintani et al. [START_REF] Shintani | Computer-Assisted Three-Dimensional Corrective Osteotomy for Malunited Fractures of the Distal Radius Using Prefabricated Bone Graft Substitute[END_REF], 3D deformity of the distal radius must include rotation deformity; 3D computer bone models could be used to assess it.

The generalizability of our results is limited since the size of study sample is small (n = 13).

Nevertheless, according to our findings, measurements based on plain radiographs and 3D computer bone models are both accurate for evaluating the deformity of extra-articular distal radius malunion. Although the differences are small and possibly within the margin of error of what current surgical techniques can achieve, our 3D method seems to provide us with a more accurate measurement of ulnar variance, particularly for dorsally angulated cases, and is helpful for measuring rotational malalignment.. .

Figure 1 .

 1 Figure 1. Measurement of palmar tilt, radial tilt, and ulnar variance on radiographs. Palmar tilt

Figure 2 .Figure 3 .

 23 Figure 2. Deformity evaluation using 3D computer bone models. 3D palmar tilt (A) corresponds

Figure 1

 1 Figure 1

Figure 2

 2 Figure 2

Figure 3

 3 Figure 3

TABLE LEGENDS Table 1 .

 LEGENDS1 Radiographic and 3D measurements of palmar tilt, radial tilt and ulnar variance for each patient.

Table 1 .

 1 Radiographic and 3D measurements of palmar tilt, radial tilt and ulnar variance for each patient.

											Axial
											rotational
											deformity
	Patient	Affected	Palmar tilt (°)			Radial tilt (°)			Ulnar variance (mm)	(°)
		wrist	Radiographic	3D	Difference Radiographic	3D	Difference Radiographic	3D	Difference	3D
	Dorsal deformity group (n = 7)
	1	L	-28	-30	2	19	12	7	3.5	4.4	0.9	-
	2	L	-10	-9	1	12	9	3	-1.5	-0.7	0.8	2
	3	R	-5	-2	3	14	14	0	4	5.5	1.5	-
	4	R	-14	-13	1	14	12	2	3	5.5	2.5	5
	5	L	-42	-39	3	5	2	3	1	2.4	1.4	5
	6	L	-11	-15	4	15	16	1	3.5	4.8	1.3	12
	7	R	-21	-19	2	15	19	4	0	0.6	0.6	3
	Average		-19	-18	2	13	12	3	1.9	3.2	1.3	5

R: right; L: left.

The authors received no financial support for the research, authorship, and/or


The first use of laparoscopy to treat pelvic ring fractures: a case report

Keywords: Laparoscopy, Pelvic ring fracture, Plate fixation

Introduction

Pelvic ring injuries pose major challenges for the trauma surgeon. Given the complications of open surgeries, percutaneous techniques have become increasingly popular, but laparoscopy has never been employed for internal osteosynthesis of the pelvic ring.

Presentation of Case

We describe a 34-year-old male with a pelvic ring fracture (grade AO/OTA 61B2.1b). The anterior pelvic arch was successfully plate-fixed using a laparoscopic technique. This is the first report of such an approach to treat pelvic ring fractures.

Discussion

Our principal point is that "laparoscopic internal fixation" delivered an in situ result as good as that of open surgery, but we required only four trocar portals.

Conclusion

We describe a novel laparoscopic approach to treatment of pelvic ring fractures.

Introduction

Pelvic ring injuries pose major challenges for the trauma surgeon [START_REF] Halawi | Pelvic ring injuries: Surgical management and long-term outcomes[END_REF]. Given the complications of open surgeries, percutaneous techniques have become increasingly popular [START_REF] Stevenson | Percutaneous internal fixation of pelvic fractures[END_REF]. However, such techniques cannot be used to fix the anterior arch of the pelvic ring. Laparoscopy is better than open surgery when treating digestive tract [START_REF] Quah | Laparoscopic appendicectomy is superior to open surgery for complicated appendicitis[END_REF][START_REF] Wei | Laparoscopic versus open appendectomy for acute appendicitis: a metaanalysis[END_REF] and kidney conditions [START_REF] Nouralizadeh | Comparison of Open Versus Laparoscopic Versus Hand-Assisted Laparoscopic Nephroureterectomy: A Systematic Review and Meta-Analysis[END_REF]. In the context of pelvic ring surgery, laparoscopy has been used only to extract material or to treat tissue migration [START_REF] Thati | Laparoscopic extraction of fractured Kirschner wire from the pelvis[END_REF]. To the best of our knowledge, laparoscopy has never been employed for internal osteosynthesis of the pelvic ring. We here describe the first use of laparoscopy to treat such a fracture.

Case and technique

This case report adheres to the SCARE checklist [START_REF] Agha | For the SCARE Group. The SCARE 2018 statement: updating consensus surgical CAse REport (SCARE) guidelines[END_REF].

A 34-year-old male without medical or surgical history was admitted to the intensive care unit of our level 1 trauma centre after a road accident. He had severe head and pelvic ring injuries.

Emergency pelvic radiographs (Figure 1) and computed tomography revealed a lateral compression fracture with internal rotational instability; fracture of the left sacral wing (Denis grade 1) was associated with bilateral fracture of the obturator bone frames (grade AO/OTA 61B2.1b). We decided to fix the posterior arch of the pelvic ring, but also the anterior arch, as recommended by the AO [START_REF] Tile | Internal fixation of lateral compression fractures (type B2)[END_REF]. Surgery was performed by senior trauma (RDF) and urological (JM) surgeons. We first inserted two, left, sacroiliac cannulated screws (TIS; Königsee Implantate GmbH, Allendorf, Germany) via a classical percutaneous approach aided by inlet and outlet fluoroscopic views. We next performed laparoscopy. The peritoneal cavity was entered using an open laparoscopy technique via a 10/12-mm optical trocar positioned below the umbilicus. The pneumoperitoneum was insufflated to 12 mmHg and the intestinal loops repressed by placing the patient in the accentuated Trendelenburg position. Two further 10/12-mm trocars were added, triangulating the left and right pararectal areas. The Retzius space was opened using bipolar forceps and monopolar scissors. Dissection proceeded to the endopelvic fascia covering the base of the prostate. A fourth trocar (10/12 mm) was then created in the pubis to allow passage of instruments required for screw insertion. The pubic arch was carefully dissected. The right and left coronae mortices were ligated with bipolar forceps. Use of a monopolar hook and a dissector facilitated release of the pelvic bone surface. After dissection was adequate (Figure 2A), a 10-hole, Matta curved plate (Stryker GmbH, Selzach, Switzerland) was inserted through a trocar and retrieved using forceps.

When the plate was appropriately positioned on the anterior arch of the pelvic ring, it was fastened using a ball-spike pusher inserted into a trocar. A plate screw inserter (associated with a long drill guide) was then sequentially introduced into the various trocars to ensure appropriate orientation of all screws. The two key screws (those at the ends of the plate) were first inserted using a long screwdriver. When the plate was stably fixed to bone, the other screws were inserted. All screws required for reliable fixation were successfully inserted (Figure 2B). Fluoroscopy was then performed. Given the space required by the laparoscopic instruments and surgical manipulation, screw placement under direct fluoroscopy was impossible. Surgery required 4 h; blood loss was less than 100 mL, reflecting, principally, evacuation of a hematoma. We encountered no intraoperative complications; the patient did not react negatively to laparoscopy; and the postoperative X-rays were satisfactory (Figure 3).

Unfortunately, the patient died from his head trauma 16 days after the accident.

Discussion

Our principal point is that "laparoscopic internal fixation" delivered an in situ result as good as that of open surgery, but we required only four trocar portals (Figure 3). Management of pelvic ring fractures remains complex; the surgical approaches are risky. The Pfannenstiel and ilioinguinal approaches may injure the bladder, spermatic cord, iliac vessels, and the femoral and lateral thigh nerves; and/or trigger herniation [START_REF] Routt | The retrograde medullary superior pubic ramus screw for the treatment of anterior pelvic ring disruptions: a new technique[END_REF]. Developments in percutaneous screws since the 1990s have reduced intraoperative comorbidities, blood loss, operative time, negative post-operative outcomes, decubitus complications, and the infection rate; and facilitate early mobilization [START_REF] Banaszek | Technical Considerations and Fluoroscopy in Percutaneous Fixation of the Pelvis and Acetabulum[END_REF][START_REF] Gire | Percutaneous Versus Open Treatment of Posterior Pelvic Ring Injuries: Changes in Practice Patterns Over Time[END_REF]. However, percutaneous screwing remains somewhat risky and technically challenging [START_REF] Stevenson | Percutaneous internal fixation of pelvic fractures[END_REF][START_REF] Starr | Superior Pubic Ramus Fractures Fixed With Percutaneous Screws: What Predicts Fixation Failure?[END_REF]. Laparoscopy is better than open surgery when treating digestive tract and urological conditions [START_REF] Quah | Laparoscopic appendicectomy is superior to open surgery for complicated appendicitis[END_REF][START_REF] Wei | Laparoscopic versus open appendectomy for acute appendicitis: a metaanalysis[END_REF][START_REF] Nouralizadeh | Comparison of Open Versus Laparoscopic Versus Hand-Assisted Laparoscopic Nephroureterectomy: A Systematic Review and Meta-Analysis[END_REF], associated with low rates of intraoperative complications. Despite the longer operative time, blood loss and the hospital stay are reduced.

In our case, blood loss was very low. The long operating time is explained by certain intrinsic difficulties; urological surgeons lack experience with laparoscopic dissection of the pelvic ramp. Plate handling and positioning are also challenging. Screw insertion is slower than that of open surgery because instrument manipulation within trocars is delicate. Trauma surgeons are often not familiar with spatial laparoscopic landmarks.

Our treatment requires the use of Stryker PRO Pelvis and Acetabulum System Instrumentation (Stryker GmbH, Selzach, Switzerland). Our success heralds a new approach to pelvic ring fractures; we will refine our technique further. The learning curve, especially that of operative time, requires attention.

Conclusion

We describe a novel laparoscopic approach to treatment of pelvic ring fractures. Keywords: laparoscopy; pelvic ring fracture; plate fixation.

Compliance with Ethical Standards:

Registration of research studies: researchregistry5934.

Figure captions:

Figure 1 :

 1 Figure 1: Pelvic anteroposterior X-rays taken before surgery.

Figure 2 :

 2 Figure 2: Laparoscopic views of the transperitoneal approach. Opening of the Retzius space

Figure 3 :

 3 Figure 3: Laparoscopic views obtained after the pubic arch dissection (A), during the

Figure 4 :

 4 Figure 4: Pelvic anteroposterior X-rays taken after surgery.

Acknowledgements: We thank the anesthesia team and the nurses for their logistical and technical assistance.

Conflict of Interest Statement: The authors declare no conflicts of interest.

Conflict of Interest: The authors declare that they have no conflict of interest.

Funding: There is no funding source.

Informed consent: The patient was never able to give informed consent due to the sedation required since his accident.

Ethical approval: Because of his death, the fact that the patient does not have to provide opposition in his lifetime, and in accordance with the French law "Informatique et libertés" of 2004 (Article 56), the use of health data of this patient in this case report does not require the approval of our local ethics committee.

Provenance and peer review

Not commissioned, externally peer-reviewed