Importance to include the term Superficial Musculoaponeurotic System in Medical Subject Headings and in the International Anatomical Nomenclature

Purpose: To investigate the relevance of the term superficial musculoaponeurotic system (SMAS) and demonstrate that this term is important enough to be added to the MeSH database and listed in International Anatomical Nomenclature. Methods: Terms related to SMAS were selected from original articles retrieved from the ISI Web of Science and MEDLINE (PubMed) databases. Groups of terms were created to define a search strategy with high-sensitivity and restricted to scientific periodicals devoted to plastic surgery. This study included articles between January 1996 and May 2009, whose titles, abstracts, and keywords were searched for SMAS-related terms and all occurrences were recorded. Results: A total of 126 original articles were retrieved from the main periodicals related to plastic surgery in the referred databases. Of these articles, 51.6% had SMAS-related terms in the abstract only, and 25.4% had SMAS-related terms in both the title and abstract. The term ‘superficial musculoaponeurotic system’ was present as a keyword in 19.8% of the articles. The most frequent terms were ‘SMAS’ (71.4%) and superficial musculoaponeurotic system (62.7%). Conclusion: The term SMAS refers to a structure relevant enough to start a discussion about indexing it as a keyword and as an official term in Terminologia Anatomica: International Anatomical Terminology.


Introduction
The superficial musculoaponeurotic system (SMAS), an important structure in rhytidoplasty and a term commonly used in the literature, is neither listed in Terminologia Anatomica: International Anatomical Terminology, nor in classical anatomical treatises, even though Mitz and Peyronie had described SMAS as a 'new' anatomical structure in 1976 1 . Consequently, the SMAS is referred in the literature just as a surgical structure, and is not included in the Medical Subject Headings (MeSH) of the Index Medicus database (http://www.ncbi.nlm.nih.gov/entrez/query. fcgi?db=mesh). On the other hand, publications on the SMAS have gradually become more prominent in the specialized literature, which clearly indicates the need of using the term SMAS as a keyword.
Similarly, this reasoning could also be applied to the international anatomical terminology. Therefore, the objective of this study was to investigate the relevance of the term 'superficial musculoaponeurotic system' and to demonstrate that this term is important enough to be added to the MeSH database and listed in Terminologia Anatomica: International Anatomical Terminology.

Methods
A literature search was conducted on electronic databases for original articles published between January 1, 1996 and May 25, 2009. Articles were retrieved from the ISI Web of Knowledge and MEDLINE/PubMed databases using a search strategy denominated 'Strategy-1', consisting of 'plastic AND (Superficial musculoaponeurotic system OR Superficial musculo-aponeurotic system OR SMAS)'.
All terms and expressions related to or used as synonyms of 'superficial musculoaponeurotic system', 'superficial musculoaponeurotic system' or 'SMAS' in the title or abstract of the retrieved articles were recorded and denominated as 'Type-1 words'. Compound expressions relating the term 'superficial musculoaponeurotic system' to other terms describing anatomical structures or surgical procedures were also denominated as "Type- All occurrences of 'Type-1 words' and other SMASrelated terms and expressions identified in titles and abstracts and, occasionally, as keywords (terms incorrectly used as keywords since they are not MeSH terms) were added to a list denominated as 'Type-2 words'. All identical 'Type-2 words' (i.e., having exactly the same spelling) were counted only once in the title, abstract or keywords, regardless of the number of occurrences in an article.
The word 'SMAS' was counted regardless of whether it appeared as a term (i.e., without a previous description of the acronym) or as an acronym after the full term. In order to count 'Type-2 words',  Table 1. Superficial musculo-aponeurotic system

Importance to include the term Superficial Musculoaponeurotic System in Medical Subject Headings and in the International Anatomical Nomenclature
In some of the retrieved articles, 'Type-2 words' occurred exclusively in the title or abstract or as a keyword, but there were articles in which "Type-2 words" occurred simultaneously in the 'title and abstract' or 'abstract and keywords' or 'title, abstract and keywords' of the same article. Table 2 and Figure 1 show the number of original articles retrieved per periodical, stratified by the presence of 'Type-2 words' in their titles, abstracts and keywords.
Of the 126 retrieved articles, 51.6% had 'Type-2 words' in the abstract only, and 25.4% had 'Type-2 words' simultaneously in the title and abstract. The most cited term was 'SMAS' (71.4%) followed by 'Superficial musculoaponeurotic system' (62.7%), 'SMASectomy' (9.52%), and 'SMAS flap' (8.73%), see Figure 2.   Therefore, the knowledge to carry out this approach in a safe and efficient manner is extremely important and should be easily and clearly available in databases and in Terminologia Anatomica.
Only advances in the understanding of human morphology can provide the basis for the evolution of medical and biological sciences in general.
Although the term 'superficial musculoaponeurotic system' is not listed in PubMed (it is not a MeSH term), it is interesting to note that 19.8% of SMAS-related terms were present in the keywords, as exclusive or simultaneous occurrences, and that they were used as keywords at the initiative of the authors themselves; it is not clear, though, whether permission was granted by the scientific periodicals or whether the reviewers did not pay attention to this particular requirement. It is important to note that the same search strategy was used to identify articles on SMAS in anatomy periodicals indexed in the ISI Web of Knowledge and MEDLINE databases, but no SMAS-related articles were found.
The term 'SMAS' (the acronym) was the most prevalent (71.4%) term followed by 'superficial musculoaponeurotic system' (62.7%); therefore, the full, self-descriptive term is recommended as a MeSH term, and 'SMAS', as the acronym.
On the other hand, not adopting SMAS as an anatomical structure may compromise the knowledge of facial anatomy in a surgical context [6][7][8][9][10][11] , since this is an individualized structure, even though it is not listed in Anatomical Nomenclature 12 . This type of situation demonstrates that more effective communication and integration among anatomists, surgeons, and librarians are necessary to assure the inclusion and proper indexing of this term in databases and information centers.

Conclusion
The term 'superficial musculoaponeurotic system' and the acronym 'SMAS' are relevant enough to be added to the Mesh database; moreover, their indexing in databases and inclusion in Terminologia Anatomica: International Anatomical Terminology are fully justifiable.