gms | German Medical Science

50. Jahrestagung der Deutschen Gesellschaft für Medizinische Informatik, Biometrie und Epidemiologie (gmds)
12. Jahrestagung der Deutschen Arbeitsgemeinschaft für Epidemiologie (dae)

Deutsche Gesellschaft für Medizinische Informatik, Biometrie und Epidemiologie
Deutsche Arbeitsgemeinschaft für Epidemiologie

12. bis 15.09.2005, Freiburg im Breisgau

Classification of Medical Procedures: Comparison of ICHI and Basic Coding System of CCAM

Meeting Abstract

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  • Susanne Hanser - Universitätsklinikum Freiburg, Freiburg
  • Niklas Baerlecken - Universitätsklinikum Freiburg, Freiburg
  • Albrecht Zaiß - Universitätsklinikum Freiburg, Freiburg

Deutsche Gesellschaft für Medizinische Informatik, Biometrie und Epidemiologie. Deutsche Arbeitsgemeinschaft für Epidemiologie. 50. Jahrestagung der Deutschen Gesellschaft für Medizinische Informatik, Biometrie und Epidemiologie (gmds), 12. Jahrestagung der Deutschen Arbeitsgemeinschaft für Epidemiologie. Freiburg im Breisgau, 12.-15.09.2005. Düsseldorf, Köln: German Medical Science; 2005. Doc05gmds607

The electronic version of this article is the complete one and can be found online at:

Published: September 8, 2005

© 2005 Hanser et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.



Introduction and Objectives

Information on surgical and other medical interventions constitutes an indicator for the use of health care, of hospitals in particular. While diagnoses are captured by ICD-Codes across the world, it is different for procedures. Europe- and worldwide, various coding systems are in use. There are, however, countries without any procedure classification. Data about the performance of medical procedures is rarely available and poorly comparable.

During the last years, the introduction of a common/international medical procedure classification has been discussed again. The Australian NCCH (National Centre for Classification in Health) presented the International Classification of Health Interventions (ICHI) as a proposal for an international procedure classification. An alternative way could be to use the CCAM framework for procedure classification - “Système de Codification” of the French Classification Commune des Actes Médicaux - for the generation of a procedure shortlist. We compared ICHI and CCAM Basic Coding System focusing on the appropriateness of both systems for supporting comparability of procedure data.

Materials and Methods

We used ICHI Alpha Version 2002, a trial version [1], and CCAM Système de Codification (Basic Coding System) Version V0bis from 2001[2]. ICHI is a procedure shortlist of 1421 classes, based on the Australian Classification of Health Interventions (ACHI). CCAM Basic Coding System is a framework for the multiaxial classification of procedures according to anatomical site, action (“surgical deed”) and approach/method. Using this framework, France developed a CCAM Tabular List, containing about relevant 8000 procedures, to be used for in- and outpatients.

As we had done before with classes of OPS-301 [3], we mapped ICHI classes to multiaxial CCAM codes and assessed representability and granularity. Mapping ICHI to CCAM was based on ICHI block titles: We represented ICHI contents to anatomical site, procedural type, and approch/method, using the axes of the Basic Coding System of CCAM. This resulted in multiaxial codes for ICHI procedure descriptions. In addition, we compared the architecture of both classifications, regarding coding system, hierarchy, as well as vocabulary.


Mapping. A high percentage of ICHI classes could be mapped to four-digit CCAM Codes (78,4%) due to considerable similarities between both procedure models, especially concerning anatomical site (mapping 99,3%). Representability of the action/procedural type axis was affected by a) missing CCAM codes for “incision on …” and “other procedure…” and by b) imprecise procedure descriptions in ICHI titles/blocks, e.g. “procedure for (a disease)”. The third axis for approach/method could represent more information, if ICHI blocks would provide such information. In traditional procedure classifications, information of this type is merely implicit to a great extent, so we were unable to map procedures, which in practice are performed using different approaches or techniques. Table 1 [Tab. 1] and 2 [Tab. 2] exemplarily show the mapping results for panendoscopy procedures, e.g. 1005=>HZQE.

Comparison of ICHI/CCAM Architecture

Coding system: ICHI blocks are coded using sequential numbers, while the hierarchical information to anatomical site and procedural type is not coded. CCAM provides multiaxial four-digit codes, representing body system, anatomical site, action (procedural type).

Hierarchy: ICHI tabulates each block according to 1) anatomical site/ specialty, 2) anatomical site/detail, 3) procedural type. The result is a formal, consistent hierarchical procedure list. CCAM’s multiaxial classification system supports different hierarchies; it makes sense to choose a hierarchical tabulation oriented on the axis for body system/anatomical site.

Vocabulary: ICHI titles (blocks) do not use a controlled vocabulary, which in some cases, leads to ambiguities. The procedure descriptions are either “clinical” (proctocolectomy) or “formal” (excision procedures on liver, i.a. for hepatectomy) and of varying granularity. CCAM uses a controlled vocabulary to describe procedures unambiguously and in a consistent granularity, equivalent or slightly coarser than “formal” procedure descriptions of ICHI.


Mapping ICHI classes to CCAM, we found that a complete mapping was possible in a high percentage, due to a high degree of similarities, especially concerning the anatomical site classification. Incompatibilities result from undefined classes in CCAM (e.g. “other”), from unspecific descriptions (“procedures for…”), and from missing information to approach/method in ICHI.

Comparing the architectures of ICHI and CCAM Basic Coding System, we found CCAM being a well defined coding system, appropriate to generate classes which are consistent regarding granularity of procedure description and class boundaries, appropriate for statistical purposes - presumed the integration of additional codes for residual classes (“other”). With a universal modeling and an elaborated application guide [2] in combination with the simplicity of the coding system, CCAM facilitates a correct and consistent assignment of codes, which is a precondition for improved data quality. The hierarchical structure of ICHI shows rather well structured elements, too, with the potential to facilitate statistical analysis, but these elements are not represented in a well applicable coding system. Block titles describe procedures in varying granularity and partially problematic ambiguity. There is also a tendency to group various combinations of anatomical sites (“… of pelvis or hip” next to “… of pelvis or femur”). Thus, statistical analysis using block texts is poorly supported.

In the case of recommending ICHI as an international procedure classification, it would be essential to improve its structure by adding a multiaxial code and by eliminating textual ambiguities and inconsistencies. With regard to the advantages of the CCAM classification architecture (accordance to European Standard EN 1828, multiaxial coding system, detailed definitions/coding guidelines, controlled vocabulary, and last but not least simplicity), we strongly recommend to structure an international procedure classification using the CCAM Basic Coding System, which we consider to be a useful basis in order to achieve comparability of procedure data and for the elaboration of local, finer classifications. This implies, of course, the generation of a tabular list of sensible procedure descriptions using the CCAM framework.


International Classification of Health Interventions (ICHI), Alpha Version (Trial Version) Last visited 20.04.05
Classification des Actes Médicaux, Version V0bis, 2001: Guide de Lecture - Système de Codification, Seite 53 ff. Die aktuelle CCAM Version V1, 2005 siehe Last visited 20.04.05
Hanser S, Zaiß A, Jakob R. Bewährter Inhalt in neuer Struktur: Abbildbarkeit von Inhalten des OPS-301 mit den Methodiken zweier medizinischer Prozedurenklassifikationen (PCS, CCAM). Informatik, Biometrie und Epidemiologie in Medizin und Biologie, 2003; 34 (3) : 244-246 (48. Jahrestagung der Deutschen Gesellschaft für Medizinische Informatik, Biometrie und Epidemiologie (GMDS), Münster, 14.-19. September 2003)