Implementation of the “EAONO/JOS Definitions and Classification of Middle Ear Cholesteatoma” - from STAM to STAMCO

Abstract

Recently, EAONO/JOS's joint consensus paper on definitions, classification, and staging of middle ear cholesteatoma was published 1 .As it is the era of collection of and report on uniform and comparable data, this is a welcome consensus statement. Currently, we are setting up a new nationwide multicenter study in the Netherlands, entitled Dutch Cholesteatoma Data, in which we would like to implement this guideline. To inform colleagues about our local experiences and choices so far, we are writing this letter.Although the EAONO/JOS consensus statements are clearly presented, we encountered some difficulties with the classification. First, we believe that the divisions of the middle ear space need further specifications. The anatomical sites as presented in the figure and the text of the consensus statements 1 can be variously interpreted and show some "blank spots. " For instance, the borders used for the anterior epitympanic space are unclear, which, in addition to the variation in anatomy and exposition in this area (canal wall up, canal wall down, microscopic, and endoscopic), will most likely result in a non-uniform registration. Second, we strongly believe that there is a primary need to elaborate on the classification rather than simplify it with a staging system. Gathering classification data on extent, complication, and ossicular state, using an easy format will make it possible to monitor surgical outcomes. This will allow comparisons of data among different hospitals, publications, and classifications. When large numbers of data on outcomes in relation to classification become available, results can be used to propose different stages. To improve the practical applicability of the EAONO/JOS joint statement in our national study, we have proposed to our participating ENT surgeons the following modifications:1. The borders of divisions of the middle ear and mastoid are further defined, and consequently, the figure of the consensus paper is refined [1] . In the EAONO/JOS consensus statement, the middle ear and mastoid spaces are divided into four sites to classify the extent of the cholesteatoma: difficult access sites (S), tympanic cavity (T), attic (A), and mastoid and antrum (M). The difficult access sites (S) further include S1 (the supratubal recess) and S2 (the sinus tympani). We propose to define the anatomical divisions of the middle ear and mastoid in more detail using surgical and anatomical landmarks. These landmarks based on a selection of published papers on this topic are highly likely to be identified both on CT scans and during all types of surgical approaches and are thus less prone to various interpretations [2][3][4] . Table 1 summarizes our suggestions for further specification of borders between the different sites of the middle ear and mastoid. In addition, Figure 1 shows the updated illustration based on those refined borders.An advantage of a more detailed description of these borders can be illustrated by the following examples that describe the difference between A and S1 ant...

A Retrospective Analysis and Comparison of the STAM and STAMCO Classification and EAONO/JOS Cholesteatoma Staging System in Predicting Surgical Treatment Outcomes of Middle Ear Cholesteatoma

“…Differences were solved by discussion. The extension of cholesteatoma was based on the anatomical sites of mastoid and middle ear space as described by Merkus et al (2). The STAM classification was classified according to the scale (STAM 1-3) by Merkus et al…”

“…In the STAM classification (Table 1), the middle ear and mastoid region are divided into four sites to simplify the description of the cholesteatoma extension. Merkus et al (2) adjusted the STAM classification by further defining the anatomical borders of those sites and by including the complications caused by the cholesteatoma (C) and perioperative ossicular chain status (O), resulting in the ''STAMCO classification.'' They suggest registering the extension of the cholesteatoma in an ascending scale referring to the number of sites affected by the cholesteatoma ( Table 1).…”

Introducing the “ChOLE” Classification and Its Comparison to the EAONO/JOS Consensus Classification for Cholesteatoma Staging

“…The EAONO/JOS definitions and classification have been criticized by Merkus et al (13) mainly for their anatomical borders and the negligence of the ossicular chain status. They proposed a more accurate definition of the attic and epitympanic space and took into account anatomical bony borders visible on preoperative CT scans.…”

Evaluation of the SAMEO-ATO surgical classification in a Dutch cohort

“…Since uniform registration to aid comparison of surgical outcomes is the aim of the SAMEO-ATO, registering disease characteristics and outcomes are important too. Disease characteristics (the pathology) can be registered by means of the STAMCO classification for example [8]. Classification of both surgical outcomes by means of the SAMEO-ATO and the classification of the pathology should always be performed together.…”