Once a translation is completed, the burden of translation lessens considerably. However, translating SNOMED CT is shooting at a moving target, or like chasing Aristotle’s famous turtle: whenever a finish line has been crossed, the turtle has moved on. 

With every new release, SNOMED CT expands with new concepts; moreover, the definition or even the FSN of the concepts that are already translated may change and render an earlier translation inaccurate. In order to keep a translation usable, it must be maintained.

This chapter will address the different streams of incoming work of mature translations (new content, changes in existing content, reactivated content). Also, maintaining consistency, updating guidelines and principle decisions after the initial translation is included.

5.1 New content

New content is added to the SNOMED CT International Edition by monthly releases.

On average, 700 new concepts per month based on releases in 2022, with significant variability in hierarchy composition.

• all of them require translation if the complete SNOMED CT is to be available in the target language. Most of the new concepts require manual translation, but for selected areas such as clinical drugs, template-based batch translation might be leveraged, but this depends on the target language characteristics and the results of ongoing research. 
• less than 5% of new concepts are direct replacements of ambiguous inactivated concepts with a similar translation
• 15-20% of new concepts are aligned with the SNOMED CT International Drug Model. Those usually benefit (and sometimes require, like most clinical drugs) template-based translation or quality assurance, as naming conventions for multi-ingredient clinical drugs are complex to craft or review manually 
• average 50-100 new descriptions in existing concepts. In concept-based translations those might be ignored, or triaged to a simplified manual inspection workflow that closes the task if no changes are deemed necessary.

5.2 Changes in existing content

Changes in the lexical representation of existing source concepts are made in every new international release.

• FSN changes usually require manual inspection to identify potential shifts in meaning or a need to align to recent remodelling or new naming conventions (e.g. recent new perspective on osteotomies). 
• In recent releases FSN changes usually arise from the enforcement of new naming conventions and the QI project. While the new conventions are usually only enforced on new content and on areas being revised by the QI project, translation projects might prefer on a case by case basis to extend the revision to existing translations sharing the same source pattern.
• Inactivated source descriptions may require manual inspection as old translations might have been influenced by obsolete (e.g. deprecated organism names) or terms inactivated as not semantically equivalent.
• Changes in preferred terms should not affect concept-based translations that base their synonyms on descriptions that accurately represent the meaning of the source FSN. However, the use of translation memories, machine pre-translations and template-based text generation might have introduced undesirable characteristics of term-to-term translations if the target preferred term is directly derived from the source preferred term.

5.3. Reactivated content

Reactivated concepts usually represent a very small portion of content updates, but they might result in duplicate translations in some cases.

Inactivated concepts that have active translated descriptions are not usually considered a priority to trigger reviews, but in some cases they are relevant to local implementations and require follow up (particularly if the concept was inactivated as ambiguous. 

5.4 Content change reports

Snomed International publishes monthly release notes which give an overall view of the content change in the last release. However, for translation there is a need for a record of each change. Also, NRCs which have only translated parts of the international edition, there is also a need for filtering out changes which affect the national edition.

NRCs which are using Managed Service, can access the Reporting Platform, where several reports are available for the national extension, for example the Inactivated translation concepts report.

Figure 5-1: Screenshot of the Inactivated translated concept report (Reporting Platform) for Norwegian (january 2022)

Content change reports are also available in other SNOMED CT tool environments, such as TermSpace: 

Figure 5-2: Screenshot of content change report of the international edition during the March 2022 release in the TermSpace environment.

5.5 Other source for change

Other translation maintenance tasks originate in other sources than changes in SNOMED CT international edition: external feedback, internal quality improvement projects, or changes in editorial policies or style guides.

• change requests from users detecting typos or incorrect translations issues detected by the translation team 
• translation consistency across different translation periods (complete translations take years and editorial policies might change over time)
• changes in naming conventions related to the ongoing QI project might require extensive revision of previous translation.
  

5.6 Maintaining consistency, updating guidelines and principle decisions

When taking the step from initial translation to translation maintenance, a much smaller team will be required. Although in an ideal world one would keep a large and diverse group of clinicians and domain experts to review the recurring translations, this will most likely not be feasible once the initial translation project is ended. One should still strive for building up a system where domain expertise is available to a reasonable extent, such as a pool of volunteers or through formal collaboration with medical specialist organisations or by other means. A key question is, also, whether it possible to both have a small team and ensure national consensus

In a situation where the complete set of concepts in SNOMED CT are translated (this is the case e.g. in Sweden) the translation cycles might be performed quite fast and specialised terms may not receive an optimal translation, even if the overall translation is of reasonable quality. In this situation, the improvements of the translation will be organic and driven by demands of users. Such a translation will be a result of actual use: SNOMED CT areas and branches that are subjects for development projects on different levels will be reviewed as the need arises.  

During the translation project, but of course to an even greater extent once the initial project is completed, staff may leave and be replaced. This poses the challenge to preserve knowledge and maintain the expertise required to keep the new translations consistent with the older translations. Each new member of staff must be trained in the use of the guidelines, tools and processes.

During or after the translation project inconsistencies in translations may come to light. For instance, in Dutch the word ‘thyroid’ can be translated to ‘schildklier’, ‘thyroïd’ or ‘glandula thyroidea’. The first two are equally frequently used and thus different translators and reviewers will not choose consistently unless there is a guideline that governs the choice.

One approach for handling guidelines is to collect fundamental linguistic and terminological guidelines of the translation in a basic document that is kept stable over the years. Editorial agreements on principle issues which are raised during every translation cycle are documented in a separate, complementary document. This document is where decisions about individual term choices are to be found, i.e. which term of two or more possible ones the translator should choose (see Figure 5-3). The translators could also find instructions on how to spell an expression, if there are several spelling variants. The document also contains advice on such fairly general expressions that recur in the SNOMED CT material and which in the translation work should be handled in a similar way. This document is continuously replenished, which means that newer decisions revoke older ones.

Figure 5-3: Spreadsheet with principle issues for translation, Swedish version

Once a guideline is established, to achieve consistency it is not sufficient to apply it to all future translations; all finished translations that contain the term must be revised so that they will adhere to the guideline in the next edition. The efficient usage of ECL queries, including the description filters, is useful for detecting inconsistencies. This issue also emphasises the need for an easy and effective tool for batch changes.

The use and implementation of the terminology, or changes in a new version of the international edition, may periodically provide new insights that require updates of the linguistic guidelines; which in its turn may require revision of older translations.