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IHTSDO-1249

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Introduction

As part of the Quality improvement project, a review of the Procedure (procedure) hierarchy of SNOMED CT is being conducted. As outlined in Editorial Guide, Procedures are "activities performed in the provision of health care" and "Method (attribute) represents the action being performed to accomplish the procedure". Given those statements, the Method attribute is an important attribute for properly defined Procedures in SNOMED CT.

The Method attribute has a range of << 129264002 |Action (qualifier value)|, which means that method values are comprised by an Action (qualifier value). In revision of this subhierarchy, some issues were found that may lead to inconsistency in properly defining procedures. A more specific review was conducted to standardize the definition of procedures under 128422009 |Destruction using electrical energy (procedure)| which uses the values for Method (attribute) under < 129382001 |Destruction - action (qualifier value)|:

Concepts under 128422009 |Destruction using electrical energy (procedure)| use one of the Action (qualifier value) values from the table above as a value for Method (attribute), but additionally and consistently, the Description's terming include another "Action" which is the final purpose of the Procedure, For example:

33397002 |Reattachment of choroid and retina by diathermy (procedure)|,  where the action performed is reattachment by means of diathermy

14771009 |Destruction of lesion of rectum by electrodesiccation (procedure)|, action = destruction, meaning = electrodesiccation

19947008 |Repair of aneurysm by electrocoagulation (procedure)|, action = repair, meaning = electrocoagulation. 

In some cases, Actions derived from 129382001 |Destruction - action (qualifier value)| are used interchangeably to refer to actions inconsistently defined, leading to erroneous conceptualization of terms and/or concepts, for example 428381003 |Diathermy - action (qualifier value)| is used to define all sorts of surgical and non-surgical procedures, such as 28443006 |Chiropractic diathermy (procedure)|, 10371000132109 |Colonoscopic snare polypectomy of colon (procedure)| and 300022005 |Diathermy of perineal warts (procedure)|. Given that 428381003 |Diathermy - action (qualifier value)| is subsumed by 129382001 |Destruction - action (qualifier value)|, every concepts using Method = Diathermy will be classified as a surgical and destructive procedure. Electrolysis is used in the same way: 302397007 |Electrolysis to skin lesion (procedure)| and 48957009 |Epilation by electrolysis (procedure)| are two examples.

Another issue is the use of the different subtypes of Destruction /Ablation using electric energy concepts interchangeably and sometimes inconsistently according to definitions from resources. But, even the resources use those actions in the same way, leading to confusion and lack of terming standardization. Actions like Thermocoagulation, Electrocautery, Fulguration, Electrodesiccation, Cauterization and Diathermy show usage inconsistencies according to resources on Electrosurgery physical principles and the correct usage of Electrosurgical devices. A full explanation and documentation can be found here.

From 163 concepts under << 128422009 |Destruction using electrical energy (procedure)|, none is correctly modeled with neither 424244007 |Using energy (attribute)| = 18213006 |Electricity (physical force)| nor 424226004 |Using device (attribute)| which are key relationship to define and correctly classify these procedures.

While concepts like Electrocoagulation and Electrocauterization may be easily understandable, Diathermy and Electrolysis are two concepts used to describe different kinds of procedures, actions and results. Because of this, these concepts require an specific approach to better define their surgical/non-surgical nature which is a hard task given how those procedures are currently modeled and classified in the terminology.

Purpose

The purpose of this project is to build a consistent way to define Electrosurgical procedures based on the use of the Action (qualifier value) values describing the purpose of the procedure and the type of Physical force and Device used to perform the Action. Not in the scope of the project: definition of classification and issues related with the use of 129382001 |Destruction - action (qualifier value)|.

Audience and stakeholder domain

The audience for this document includes all standards terminology leaders, implementers and users but is especially targeted at those stakeholders from surgical domain, including special cases.
A further significant audience is the community of SNOMED authors that may be requested to implement the recommended specification.

Input from stakeholders

This project merges from the need to review the modeling of the 387713003 |Surgical procedure (procedure)| and based on several requests as follows:

Statement of the problem or need

Summary of problem or need

There are inconsistencies in modeling of concepts under 128422009 |Destruction using electrical energy (procedure)| due to:

• Misunderstanding of physical principles of electrosurgery

• Overlapped and interchangeable use of Action (qualifier value) values in the field of electrosurgery. For example, there are many different definitions for Diathermy: Heat therapy is commonly used. It can be divided into superficial and deep treatment. Superficial heat therapy, which includes hot packs and thermal water, acts through skin contact. Deep heat therapy is generated by the interaction of electromagnetic waves with biological tissues. Different types of waves can be used in diathermy. Long-wave diathermy (LWD), short-wave diathermy (SWD), and microwave diathermy (MWD) are the most common. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7266838/ Diathermy is considered a synonym of electrocautery by some resources, but this is erroneous https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7467049/, https://pubmed.ncbi.nlm.nih.gov/18080583/. In SCT, Diathermy should be considered a non-surgical action and inherited concepts using Diathermy for modeling need review for proper classification.

• Many descriptions for electrosurgical procedures are named with two values from < 129264002 |Action (qualifier value)| leading to the use of multiple RG´s to model the concepts, or concepts with missing RG´s, for example: 

  • 33397002 |Reattachment of choroid and retina by diathermy (procedure)|

  • 14771009 |Destruction of lesion of rectum by electrodesiccation (procedure)|

• No explicit differentiation between surgical and non-surgical procedures using electricity, for example:

  • 28443006 |Chiropractic diathermy (procedure)| and

  • 274996002 |Electrolysis of eyelash (procedure)|, both currently classified as surgical procedures

• Currently, procedures under 128422009 |Destruction using electrical energy (procedure)| are modeled consistently without neither 424244007 |Using energy (attribute)| nor 424226004 |Using device (attribute)|.

• According to resources, 128422009 |Destruction using electrical energy (procedure)| should be named Surgical procedure (procedure) / Electrosurgery procedure (procedure). "Electrosurgery is defined as the use of high frequency electric current to desiccate, coagulate, and fulgurate biological tissues". "Various clinical outcomes could result depending on the shape of the active electrode and surface area in contact with the tissues." https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6377004/

• Giving the referred definition above, electrosurgery procedures shouldn't be fully defined until they are modeled with 424244007 |Using energy (attribute)| = 18213006 |Electricity (physical force)| and, to perform the procedure, a device is needed.

• Some procedures described as electrosurgery are actually using the indirect Physical force produced by the passage of electrical current through a wire or device, such concepts should be modeled with 424244007 |Using energy (attribute)| = 88999006 |Heat (physical force)|

• The issue originates from resources defining Diathermy and Electrosurgery as synonyms, which is erroneous.

• There are concepts referring to apply Electrical current with destructive purpose to an organ or structure without any mention of an associated pathology (e.g. 301760002 |Diathermy of ovary (procedure)| and 75603009 |Fulguration of scrotum (procedure)|), leading to confusion about the real purpose for performing the procedure. This issue will be corrected in another project.

Proposal

• To develop a Template to consistently model Electrosurgical procedures using the Action (qualifier value) values which are the ultimate task of the procedure and the Energy (physical force) and the Device (physical object) which provides the mean by which the action is performed.

• To evaluate the need for "combined" Action (qualifier value) values named with the prefix "electro", followed by the result of applying electrical current to biological tissues (e.g. "electro-desiccation", "electro-cautery") and if possible, avoid the use of such actions. While actions may be modeled with the Energy and the device used, the procedures modeled like "ElectroX (procedure)" will be kept in the  terminology as intermediate groupers.

• To reclassify 428381003 |Diathermy - action (qualifier value)| and 129443004 |Electrolysis - action (qualifier value)| under 129264002 |Action (qualifier value)| to be used in non-surgical procedures. Adding Surgical diathermy and Surgical electrolysis for better classification of surgical and non-surgical procedures.

• For non-surgical procedures using Diathermy and Electrolysis, create Therapeutic diathermy (regime/therapy) and Electrolysis procedure (regime/therapy) under Physical therapy procedure (regime/therapy).

• For procedures with Diathermy and Electrolysis in  descriptions, but referring to destructive procedures, use Method (Action) of X using Electrical current (e.g. Ablation of X using electrical current). If the concept terming includes another action together with the "destructive" action in descriptions, use Method (Action) of X by Method (Action) (e.g. Ablation of X using coagulation). Together with these changes, current FSNs will be kept as Preferred synonyms for legacy purposes.

• Change or inactivate "destructive" Surgical procedure concepts where the target is an structure itself and not a lesion, finding or morphologic abnormality associated, unless there is an explicit and well documented procedure targeting such structures (e.g. 405323007 |Diathermy of vein (procedure)|). This issue will be reviewed and tackled in a different sub-project.

• Develop the Editorial guidance for Naming patterns and defining attributes for Electrosurgical procedures (e.g. Standardize the use of Using energy (attribute) and Using device (attribute)to model Electrosurgical procedures), as well as a template for modeling of these procedures.

Detailed analysis of reported problem, including background

The analysis of the problem was conducted by reviewing the physical principles of electrosurgery, the results of using electrical current in biological tissues, the mechanics of the action itself, technical principles for the usage of electrosurgery devices and the variability of naming patterns and definitions for different kind of electrosurgical procedures among clinicians and resources. The details of the analysis can be found here.

Subsidiary and interrelated problems

Same issues related with Electrosurgical procedures have been found for concepts under 26782000 |Cryotherapy (procedure)|, 128423004 |Chemocautery (procedure)| and 27481003 |Chemosurgery (procedure)|. The template developed for Electrosurgical procedure will be the foundation for changes in destructive procedures using other Physical forces. 

Requirements: criteria for success and completion

Criteria for success/completion

1. A template for modeling and description patterns for Electrosurgical procedures applicable to all concepts using electricity as a mean for destruction.

2. Consistent Naming pattern for Electrosurgical procedure's descriptions created and applied to all concepts in the hierarchy.

3. Set of Defining attributes for Electrosurgical procedures and standardized application to all concepts in the hierarchy.

4. Coherent subsumption of concepts in the hierarchy, both as surgical and non-surgical procedures. 

5. Editorial guidance published for SCT International Edition

Solution Development

Descriptions pattern for Electrosurgical procedures:

Pattern 1

Example FSN:

1287894009 |Repair of retinal defect by diathermy (procedure)|

287221006 |Destruction of tissue of spinal cord by coagulation (procedure)|

57103007 |Reattachment of retina by diathermy (procedure)|

703983008 |Fixation of retina by diathermy (procedure)|

Pattern 2

Example:

FSN: 51454005 |Coagulation of prostatic bed using electrical energy (procedure)|

PT: Electrocoagulation of prostatic bed

46718002 |Cauterization of lesion of cornea using electrical energy (procedure)|

PT: Electrocauterization of lesion of cornea

FSN: 48495007 |Coagulation of uterus using electrical energy (procedure)|

PT: Electrocoagulation of uterus

FSN: 303395008 |Coagulation of duodenal lesion using electrical energy (procedure)|

PT: Electrocoagulation of duodenal lesion

Concept model for Electrosurgical procedures:

Testing the template and description pattern for Electrosurgical procedures:

Iteration One

• Reclassification of concepts currently classified as surgical to classify under non-surgical procedure hierarchies. For example:

  • 28443006 |Chiropractic diathermy (procedure)|

  • 48957009 |Epilation by electrolysis (procedure)|

• Changes to descriptions and modeling for 163 concepts from << 128422009 |Destruction using electrical energy (procedure)|

• Creation of new concepts as needed for correct subsumption in the hierarchy

• Review and alignment with Proximal primitive parent rule

Iteration Two

• Revision of potential inactivation for groupers under << 128422009 |Destruction using electrical energy (procedure)| referring to procedures by method

• Review of destructive procedures using Physical forces  different to Electricity (physical force)

• Change or inactivate "destructive" Surgical procedure concepts where the target is an structure itself and not a lesion

Iteration Three

• Review concepts where the action is stated to be performed to a healthy organ rather than a lesion and fix inconsistency.