Taken from a word document. Source has not be uploaded to confluence. 

Amendment History

Review Timetable

© International Health Terminology Standards Development Organisation 2012. All rights reserved.

SNOMED CT® was originally created by the College of American Pathologists.

This document forms part of the International Release of SNOMED CT® distributed by the International Health Terminology Standards Development Organisation (IHTSDO), and is subject to the IHTSDO’s SNOMED CT® Affiliate Licence. Details of the SNOMED CT® Affiliate Licence may be found at http://www.ihtsdo.org/our-standards/licensing/.

No part of this document may be reproduced or transmitted in any form or by any means, or stored in any kind of retrieval system, except by an Affiliate of the IHTSDO in accordance with the SNOMED CT® Affiliate Licence. Any modification of this document (including without limitation the removal or modification of this notice) is prohibited without the express written permission of the IHTSDO.

Any copy of this document that is not obtained directly from the IHTSDO [or a Member of the IHTSDO] is not controlled by the IHTSDO, and may have been modified and may be out of date.  Any recipient of this document who has received it by other means is encouraged to obtain a copy directly from the IHTSDO [or a Member of the IHTSDO. Details of the Members of the IHTSDO may be found at http://www.ihtsdo.org/members/].

1 Glossary

1.1 Domain Terms

2.1 Purpose

The purpose of this document is to identify the need to review |Injury of body cavity structure (disorder)| current hierarchy. Its subtypes could be further organized by navigational concepts. This document will also analyze the different approaches and its related issues.

2.2 Audience

The audience for this document includes all standards terminology leaders, implementers, and users but is especially targeted at those stakeholders who worked with the anatomy project.  

2.2.1 Identification of stakeholders

None noted.

2.2.2 Input from stakeholders

None noted.

2.2.3 Degree of consensus on the statement of problem

None noted.

3 Statement of the problem or need

3.1 Summary of problem or need, as reported

3.2 Summary of requested solution

Organize this hierarchy using navigational concepts.

3.3 Statement of problem as understood

True navigational concept is helpful for better user browsing experience.

Unfortunately, the requestor did not identify a use case where a true navigational concept for |Injury of body cavity structure (disorder)| and its descendants are useful. Fortunately, IHTSDO-622 (artf6291) make refsets for navigational concepts and artf6291 Make refsets for navigational concepts INCEPTION.docx shed light on what may have been the reason for this request. In this artifact, the issue arise from mapping legacy coding systems to SNOMED CT where navigational concept is the link between the two. Additionally, a properly constructed navigational refset is needed for navigational concepts to be used. Without a clear use case, a navigational refset for mapping from legacy systems to a new navigational concept cannot be created and may not serve the initial purpose of this request.

This inception paper will explore the need to create navigational concepts for |Injury of body cavity structure (disorder)|, possible approach and impact.

3.4 Detailed analysis of reported problem, including background

3.4.1 Need analysis for creating navigational concepts for |Injury of body cavity (disorder)|

As of July 2016 release, |Injury of body cavity structure (disorder)| has approximately 90 concepts as its descendants. |Injury of body cavity structure (disorder)| has three (3) immediate subtypes (see the following figure). The second level subtypes are more extensive and may benefit from having navigational concepts. |Injury of internal organ (disorder)| will not be explored (see 3.5.2).

In SNOMED CT Technical Implementation Guideline (TIG), navigational concepts can be used for breaking down into manageable categories, linking related concepts of different types and from different hierarchies, bypassing levels in subtype hierarchies, and displaying in different orders. This may address the requestor's intention to map legacy coding systems to SNOMED CT where it needs to display into manageable categories, different orders and from different hierarchies. It could also serve to link concepts when the logical definition might not be applicable. However, this need may only be suitable in a local context, and not a international context.

Open

3.4.2 Need analysis for creating grouper concepts for |Injury of body cavity (disorder)|

What may be useful in an international context is to organize using grouper concepts. The advantages over a true navigational concept are: 1. allowing auto-classification of the subtypes by fully defining the grouper concept; and 2. allowing data retrieval and analysis, e.g. list all injury to <body site>, or list all <types of injury> to abdominal cavity. Grouper concept has semantic meaning because it is modelled with is-a and attribute relationships. If not careful, however, creating grouper concept with explicit disjunction, negation, conjunction creates ambiguity instead of clarity, as mention in artf6291 Make refsets for navigational concepts INCEPTION.docx. This approach would need alignment with the Anatomy project and facilitate browsing and aggregation.

E.g.:     Injury of bronchus… (F)

            Injury of diaphragm (F)

            Injury of esophagus… (F)

            Injury of heart… (P)

3.4.1.1. Alignment with the Anatomy project

Some of the benefits that can be considered are:

1. Aligning with the anatomy content in SNOMED CT. Reviewing this hierarchy based |Body structure| hierarchy may help identify missing anatomy content. The approach is clear, provide easy navigation for users because users are familiar with it.

2. The anatomy within the same group can be extensive and cause long list which users have to go through. Grouper concept that can break these further into smaller chunks that would ease browsing, searching, and aggregating. Once the hierarchy can no longer be grouped by anatomy and the list of subtypes are still extensive, the next approach can be taken such as the morphology seen in the example below.

3.4.1.2 Addressing the meaning of "Injury of body cavity" in the context of injuries

Anatomically, body cavity by itself is a space that is a three dimensional but non-material entity. A space cannot be injured. However, the wall lining which forms the body cavity can be injured. The question is, does |Body cavity structure (body structure)| includes the cavity AND its wall lining? The following examples indicated that |Body cavity structure (body structure)| involves both the lining and the cavity.

Clinically, describing an injury to a body cavity means that there is injury (penetrating or otherwise, open or closed) to the wall lining of the cavity. A penetrating/open wound would also affect the cavity.

Additionally, the organ/anatomical structure within that body cavity can also be injured. However, current anatomical hierarchy does not include the organs/anatomical structure as subtypes. Therefore, we can assume that injury to body cavity structure does not include related organ/anatomical structure unless specified.

In general, the current hierarchy in SNOMED CT reflects this understanding. 

Open

Open

3.4.1.3.     Concept with a combination of conditions (X with Y patterns)

Many of the subtypes under this hierarchy is a combination of conditions. Based on the findings from Updated elaboration phase document for artf6166 X with Y, X due to + slide deck from today's authoring meeting -topc7221, these subtypes falls under Pattern 3: X situation with (co-occurrence) and due to Y situation. Please refer to the figure below taken from artf6166 elaboration phase document:

Open

3.4.1.4.     Modeling primitive vs. defined concepts

More than half of the concepts under this hierarchy are still primitive which may be due to the inability to fully define this concept. These concepts will need to be manually placed as subtype or supertype if grouper concepts are to be created, and some concept will miss the ISA relationship, as in the following example.

E.g.:     |Injury of lung with open wound into thorax (disorder)|. This should be the supertype of |Lung laceration with open wound into thorax (disorder)|, but was not classified because it is a primitive concept. 

Open

To address this issue, effort should be made to review the modeling of these concepts and if it can be fully defined by refining the relationships. Example of these types of primitive concepts are:

• Bile duct/gallbladder injury with open wound into cavity (disorder)

• Compartment syndrome of abdomen due to trauma (disorder)

• Hematoma of spleen without rupture of capsule AND with open wound into abdominal cavity (disorder)

• Minor laceration of liver with open wound into abdominal cavity (disorder)

• Stellate laceration of liver with open wound into abdominal cavity (disorder)

Creating a fully defined grouper concept instead of true navigational concept would be advantageous for auto-classification. This may be achieved with the current model because almost all of the concepts have values for ASSOCIATED MORPHOLOGY and FINDING SITE.

The FINDING SITE to an open wound (as seen in the example figure above) seems correct if |Thoracic cavity structure (body structure)| involve both the wall lining and cavity, because a cavity/space by itself cannot be injured. 

3.4.1.5. Grouping by anatomy (FINDING SITE) and morphology (ASSOCIATED MORPHOLOGY)

The requestor have suggested a sample solution – by reviewing |Injury of mouth (disorder)|, Synonym: Injury of oral cavity. Most of these concepts are fully defined.

The subtypes are arranged according to the anatomy and morphology. The same anticipated problem are seen in this example: Dependency on anatomy content and long list based on the anatomy of “mouth”. However, grouping based on morphology managed to categorize concepts into smaller and manageable view. The following figure shows this example:

Open

We can also see grouper concepts can exists at so many level. With the same example, more grouper concept can be made according to types of injury, e.g. Abrasion injury of the mouth region, Avulsion injury of the mouth region, Fracture of the mouth region, etc. These terms are not used clinically. The question now is, how far should we go at creating NC and at which level should be enough to help user to navigate easily? Perhaps a guideline or a matrix for this would help provide consistency throughout the content.

3.5 Subsidiary and interrelated problems

3.5.1 Review the definition description for |Traumatic injury (disorder)|

This paper also found the duplicated definition description for |Traumatic AND/OR non-traumatic injury (disorder)| and its child concept |Traumatic injury (disorder)|.

The definition for |Traumatic injury (disorder)| could be further refine to reflect the ASSOCIATED MORPHOLOGY of Traumatic abnormality: “Disorder resulting from physical damage to the body caused by external force”.

3.5.2 Review |Injury of internal organ (disorder)| as a child concept for |Injury of body cavity (disorder)|

Injury to “internal organ” does not seem to belong under this hierarchy. The current anatomy for |Body cavity structure (body structure)| or its siblings under |Anatomical space structure (body structure)| does not include organ or body part. Therefore, there is a need to align the concept according to this definition. Revisiting clinicians on their opinion, whether injury of body cavity includes internal organ, should also be done for clarity.

3.5.3 Confusing FSN for |Injury of body cavity (disorder)| and |Body cavity structure (body structure)|

The term “body” in |Injury of body cavity structure (disorder)| and |Body cavity structure (body structure)| is confusing.

Open

The children of |Injury of body cavity structure (disorder)| includes structure from |Thoracic cavity (body structure)|, |Abdominal cavity (body structure)|, and |Pelvic cavity (body structure)|; which is subsumed by |Trunk body structure (body structure) and NOT just (Body cavity structure (body structure)|

Additionally, elsewhere in SNOMED CT, the term “body” does not specify the trunk at all, as seen in the child concepts for |Anatomical structure (body structure)|:

-       Body part structure (body structure)

-       Body organ structure (body structure)

-       Body system (body structure)

-       Body region structure (body structure)

4 Risks / Benefits

4.1 Risks of not addressing the problem

End-users may find difficulty in navigating, searching, and aggregating appropriate concepts under |Injury of body cavity (disorder)|. The current modeling may also be confusing without proper guidelines.

4.2 Risks of addressing the problem

Minimal risks to the end users. The risk is more on the high effort on the authoring team to address a small number of concepts (about 90 concepts under this hierarchy). However, there is a need to review the modeling of these concepts and the anatomy.

5 Requirements: criteria for success and completion

5.1 Criteria for success/completion

1. Clearly worded FSN, which will be based on the anatomy (FINDING SITE) as priority and type of injury (ASSOCIATED MORPHOLOGY)

2. Fully defining the concepts

3. The hierarchy has been reviewed to ensure

   1. Content is aligned with anatomy

   2. Review primitive concepts to ensure it is correctly placed.

   3. Editorial guideline for reproducibility in other hierarchies.

5.2 Strategic and/or specific operational use cases

The outline fit with IHTSDO strategic goals:

• 1.Make it easier to use SNOMED CT for priority use cases

• 1a.Improve understanding of SNOMED CT use in order to inform future directions

• 2.Produce robust terminology standards that are “fit for purpose” for priority use cases

6 Outline Possible Technical Approaches and Concept Model

6.1 Indicative Solutions

6.1.1 Approach One: Creating grouper concepts

This section will explore the approach and patterns for creating grouper concepts that are consistent.

The approach should be consistent throughout SNOMED CT, especially in similar hierarchies. Consistency will give user a better navigation and searching capability because the structure for navigating is familiar to the user. Creating navigational concepts should then reflect the meaning for the group it represents. This mean looking at the subtypes’ concept model for patterns.

Creation of a guideline which contains:

1) Modeling for this hierarchy

• Correct FINDING SITE for a fully defined concept

• Correct modeling for combination of concepts following Pattern 3: X situation with (occurrence) and Y situation

2) Consistency in naming approach that are usable, reproducible and understood. Order of importance is also helpful to guide authors. E.g. maintain anatomy as first approach, followed by morphology, then types of devices, etc. Since the parent concept is |Injury by body site (disorder)|, grouper concept by anatomy (via FINDING SITE) should be priority, followed by morphology (via ASSOCIATED MORPHOLOGY).

3) Fully defined grouper concepts to aid in auto-classification of subtypes.

• Review all subtypes to ensure correct placement.

• Review other concepts under |Injury of body cavity (disorder)| to ensure the concepts are not ‘missed’ from being grouped, especially the primitive concepts. This is the only time where the modeling may need to be reviewed, but this is beyond the scope of the project.

Example 1:

|Open wound injuries into thoracic cavity| was created as a grouper concept for |Injury of thoracic cavity (disorder)|. This grouper concept is based on the “open wound” morphology, done only when grouping by anatomy can no longer be done or sufficient. The child concepts under |Injury of thoracic cavity (disorder)| reduced from 12 to 5 after the grouper concept was created.

Open

Example 2:

The same approach is done for |Injury of abdominal cavity (disorder)|. |Open wound injury into abdominal cavity| was created. The child concepts under |Injury of abdominal cavity (disorder)| reduced from 21 to 5 after the grouper concept was created.

Open

6.1.1.1 End user Impact of approach one

1. Consistent approach for |Injury of body cavity (disorder)| and similar concepts such as in |Injury of mouth (disorder)| and |Injury of nasal cavity (disorder)|.

2. Better viewing by grouping concepts together and reducing the long lists of concepts.

3. There is a more complete model or meaning.

7 Indicative Project Plan

7.1 Scope of elaboration phase

Estimated project size: Small to medium

Forecast project velocity and duration: 1-3 man month if only dealing with |Injury of body cavity (disorder)|. The consistent pattern seen in the model may shorten the duration.

Review: Less than 100 concepts to be reviewed under |Injury of body cavity (disorder)|.

Create: No more than 10 grouper concepts may need to be created under |Injury of body cavity (disorder)|.

Preventing recurrence of problem: The problem is classifying primitive concepts. Changes from the anatomy project is expected to give better resolution. Long complex pre-coordinated concept should not be anticipated in future concept creation.

7.2 Projection of overall project size and resource requirements

7.2.1 Expected project resource requirement

The project resource requirement is classed as small – 1 person.

7.2.2 Expected project impact and benefit

The project impact is small to medium– The improvement will contribute for better browsing for end-users and maybe data analysis for listing types of injuries. .

7.2.3 Indicative resource estimates for elaboration, construction, transition and maintenance:

Elaboration phase:      3-6 month person month effort

Construction and transition phase:     Approximately 100 concepts to be authored. Half may be done by classifier, but most effort may be due to the primitive concepts.

Maintenance phase:    The existing concepts looked quite mature. Expecting less than 50 new ‘frequently used’ concepts requests in first 3 years.

[1] http://www.who.int/classifications/icd/adaptations/iceci/en/

[2] http://www.bls.gov/iif/oshoiics.htm