IHTSDO-977 Naming convention for synonyms to support anatomy SEP model

IHTSDO Content development – fast track (simple/single changes)

Title

Naming convention for synonyms to support anatomy SEP model

Version Information

Document review - see approvals below. 

Statement of problem as requested or initially identified

The SEP (Structure, Entire, Part) model is the foundation in anatomy for supporting logical concept modeling for clinical content such as procedures, findings and disorders in SNOMED CT. The recommended naming conventions for fully specified names of Structure concept (S concept), Entire concept (E concept), and Part concept (P concept) are:

• Structure of X (body structure), or X structure (body structure)

• Entire X (body structure) or X entire (body structure)

• X part (body structure), or Part of X (body structure)

However, there is no clear guidance for preferred terms and synonyms for anatomy. The issue has been raised by terminology users and editors in national release centers. For example, 'Liver' is a synonym for both 'Liver structure' and 'Entire liver'. This synonym does not provide any additional facility for searching since both FSN and preferred term already contain the word 'liver'. Furthermore, synonym 'Liver' can cause confusion as to whether it refers to S concept or E concept unless the FSN or concept ID is provided. Therefore, the policy for preferred terms and synonyms in anatomy needs to be developed. The existing descriptions need to be changed to avoid potential confusion.

Relevance to International edition

This is a data quality issue in the international release.

Related changes impacted by this content development request

The concepts in other hierarchies, which use these anatomy concepts in modeling, will be reviewed. Some changes to concept modeling might be required if concept inactivation is needed.

Agreed scope statement

Description changes in this project will ensure consistency for supporting the SEP model.
The identified issues to be addressed in this project include:

1. 520 FSNs or PTs do not contain the word 'entire' for 260 E concepts. 

2. 2,300 Synonyms do not contain the word 'entire' for 2,000 E concepts based on hierarchical relationships.  

3. FSNs contain the word 'entire', but about 9,000 synonyms do not contain the word 'entire' for 7,500 E concepts. 

Identify additional changes

The following two additional changes are identified during the analysis for this project. However, they are out of the scope for this project.

1. The S concepts for Cell have not been populated. The concepts related to cells are not in the scope for this project until the S concepts for cells are fully populated.

2. Some E concepts do not have a parent concept that is an E concept. This has been addressed in the new anatomy model, therefore it is out of the scope for this project.

Solution proposed

A term without the word of 'structure' or 'entire' as short description could be useful, such as liver, skin, bone, and muscle. However, it could cause confusion when the same term is assigned for different concepts, in particular, when concept IDs or FSNs are not available. The clarity can be improved by only adding such term to either S concept or E concept, but not both. The question is which is more suitable.
From the perspective of clinical usage and concept modeling, the E concepts are only used for specific cases, such as congenital short growth, amputations, and absence of entire body structures etc. It is important to include the word 'entire' in all descriptions to indicate the entirety. The omission of 'entire' from descriptions could cause misinterpretation of whether it is entire or any part of it. S concepts are most commonly used for modeling procedures or findings/disorders involved in a body site that can be either entire or any part of a structure. A term without the word 'structure' would still meet the most common usage for clinical practice.
In conclusion, all descriptions for E concepts must contain the word 'entire' to avoid confusion. A description without the word of 'structure' or 'entire' would only be suitable for S concept. The naming convention for synonym needs to be added in the editorial guide and the changes need to be applied to the existing content.

Stakeholder input

E concepts represent the entities that match to the FMA from an ontological perspective. The mapping between SNOMED CT anatomy and FMA are based on E concepts.
James Case agreed that clarity can be improved by including the word 'entire' in descriptions for E concepts.
The input from Peter Williams was that the proposed changes can be made in batch. The process will not have impact to the SCA tool if each task only has 100 description changes. The result of these changes will help to identify E concepts by descriptions.

Impact assessment

The description changes will improve consistency and avoid confusion for choosing S concepts or E concepts. This is important and useful for not only concept modeling in SNOMED CT but also using anatomy concepts in information model such as openEHR, HL7 FHIR, CDA, and HL7 messaging. The impact to users and systems is minimum and there is no requirement for software change. 

Risk assessment

The potential risk of making description changes could be performance impact to the content editing. There will be a large number of description changes for review but with comparatively small effort.
A term without the word of 'structure' or 'entire' could be made as preferred term. However, this will involve a very larger number of changes to description types. Since this kind of terms is only available for S concepts, it should meet most requirements. The changes can be made in the future if there are requirements.

Approval process

Priority

Specify the basis for the above priority assignment

It is one deliverable for the anatomy project, which has been planned for January 2017 release. The improvement of consistency will reduce potential modeling errors in the procedure, finding/disorders and observable hierarchies.

Content editing

For the issue 1:

1. Retire FSNs and/or Preferred terms

2. Add new FSNs and/or Preferred term with word 'entire'

All 262 concepts identified have a parent concept that is an E concept though FSN does not contain the word 'entire'. In the anatomy hierarchy, a concept must be a E concept if it has a superconcept that is E concept. Furthermore, E concept can be a subconcept of S concept. S concept cannot be a subconcept of E concept. This project will address 262 concepts which excludes cell concepts that are out of the scope of this project. Therefore, it is relatively safe to make description changes without retirement of concepts. This would be an exception to avoid retirement of a large number of concepts.

For the issue 2 and 3:

1. Retire synonyms that do not have the word 'entire' for E concepts.

2. Adding new synonyms if the description with 'entire' does not exist. 

Details of content changes

There will be no frontend editing in the SCA. The steps are described in content editing section.

Manual quality check

A routine review needs to be completed in the SCA tool when the batch changes are completed.

Automated quality check

Query descriptions in the daily build of RF2 snapshot. This could also identify further changes for new additions.

Publish to release branch

January 2017