B- Middle Meatal Antrostomy
In recent years, the most significant change in FESS technique has been the recognition of the need to preserve normal anatomy in order to have postoperative normal nasal functions. The importance of mucosal preservation leaving behind intact mucosa-lined cavities is essential for proper postoperative healing. This becomes even more critical in the all-important area of the natural sinus ostium and the following sinus drainage segment.
In MMA the functional objective is achieved when the natural maxillary sinus ostium is visualized and possibly widened to improve sinus drainage and ventilation. Emphasis on identifying the natural ostium early during surgery preserving most of its lining and including it in the most anterior part of the antrostomy is well documented in the following videos. If there is an accessory ostium, it should be included in MMA at one of its edges (usually at the posterior end of MMA). The use of thru cutting instruments and/or powered instruments is most beneficial to preserve mucosa. The 300 endoscope is essential for the finesse of MMA, and in some patients the 450 endoscope is also needed. Angled endoscopes are needed first to visualize the natural ostium and secondly if manipulations at the lateral part or floor of the sinus are needed.
It is a personal preference to make MMA before dealing with the ethmoidal bulla so as to preserve anatomical landmarks (the natural ostium site is slightly anterior to antero-inferior border of the ethmoidal bulla).
Visualization of the Natural Ostium:
The first step is to identify the uncinate process as demonstrated before, then to gently retract it medially with a curved probe.
In few cases the natural maxillary ostium can be seen before resecting a window in uncinate process opposite to it (Video 15).
More commonly, the natural ostium can only be seen after resecting a small window in the uncinate process opposite the antero-inferior angle of the ethmoidal bulla (Video 16).
Video 15 "Natural Ostium seen before Uncinectomy" Video 16 "Natural O. seen After Uncinate Window"
Video 17&Video 18 illustrate MMA with cold instruments.
Video 19 illustrates MMA with powered instruments.
Video 17 "MMA with Cold Instruments 1" Video 18 "MMA with Cold Instruments 2"
Video 19 "MMA with Powered Instruments"
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