Sectional Anatomy Investigation Of The Ostiomeatal Complex And Itsignificance

Objective: Ostiomeatal complex(OMC) is located in the middle of lateral nasal wall, consisting of meddile concha nasalis, processus uncinatus, semilunar hiatus, former group screening sinus, frontal recess, maxillary sinus natural openings and nasal fontanel area. In recent years, with the wide application of endoscopic technique and the development of minimally invasive surgery, relevant experts begin to try to carry out novel operation in this region. However, due to the lack of detailed clinical applied anatomy basis, the operation is difficult and with low success rate, which lead to high promotion difficulty. Scholars both at home and abroad had ever studied from the viewpoint of anatomy and imageology. But there are almost no researches via continuous thin slice technique. Thus, this paper applies the improved celloidin embedding technology to obtain continuous thin slice(0.25 mm) from both the coronal and sagittal view, by which the relations between the detailed anatomical structure of OMC and its adjacent structure can be revealed in omni-directional and three-dimensional(3D) way. It might provide reference basis to image examination and also provide important morphologic basis to the clinical operation in the region and its safe scope.Methods: Take 30 fixed dead adult heads and fetch the anterior skull bases after eliminating head diseases and traumatic scars by the CT and MRI detection. Decalcify the specimen with HCl of 20% concentration and then dehydrate the tissue blocks with alcohol of 70%, 80%, 95% concentration and absolute alcohol and ethylether alcohol successively. Then the tissue blocks are impregnated with collodion of 8%, 15% concentration in order. After embedding and welding, slice the heads into horizontal, sagittal and coronal sections of 0.25 mm with the Germany-made JUNGAG type cerebrum slicer. Observe the appearance of OMC and its adjacent region and its surrounding structure. Measure the OMC using 40 dry skull and the 10 decalcificated dead heads to obtain some contrastive data.Results: From sagittal view of the thin fault section specimens, nasal fontanelle area is a right angle trapezoid as a whole and the natural openings of maxillary sinus, which located in the nasal anterior fontanelle or(and) posterior fontanelle, can be presented oblique slit-like shape, teardrop shape and oval shape. From coronal view, the natural channel between OMC and concha nasalis media might have straight shape, "^" shape, "N" shape and "S" shape, etc. The part over the inferior nasal concha can deform both inwardly and outwardly. When the anterior ethmoid sinus fully gasify, it can merge together with maxillary sinus and concha nasalis media into a large clover shaped sinuses, and the three interchanges can form a narrow cavity the nasal passages. In the sagittal cut dry bone specimens, nasal fontanel area appears trapezoid or parallelogram. Through observing the decalcified adult head, nasal fontanel area is divided into two parts the nasal anterior fontanelle and the nasal posterior fontanelle by processus uncinatus. The percentage that maxillary sinus opens in nasal anterior fontanelle was 58% while it was 33% in cases maxillary sinus opens in nasal posterior fontanelle. 9% cases have maxillary sinus opened in both anterior and posterior nasal fontanelle. The angle between maxillary nasal tube and the horizontal plane is-30°~120°. The left side diameter is(1.74 ± 0.22) mm while the right side diameter is(1.62 ± 0.20) mm, and its absence rate is 9%.Conclusion: OMC is a novel anatomy concept put forward by the international FESS technology, which is composed by concha nasalis media, processus uncinatus, semilunar hiatus, former group screening sinus, frontal recess, maxillary sinus natural openings and nasal fontanel area. This paper shows that the maxillary sinus inside wall connects to the former group ethmoid sinus bottom wall via a thin bone plate with a thickness of 0.1 mm. Therefore, successful operation through maxillary sinus should avoid cutting through this bone plate into ethmoid sinus. When ethmoid sinus drainage operation is carried out, exudate can shunt to the maxillary sinus and then leads to maxillary sinus infection, causing recurrent and unhealed. nasal fontanel area is divided into nasal anterior fontanelle and nasal posterior fontanelle by processus uncinatus. The key point to maxillary sinus drainage operation is to confirm its opening location. It is generally believed that maxillary sinus naturally opens in nasal anterior fontanelle. In addition, opening also can appear in nasal posterior fontanelle and nasal bone between anterior and posterior fontanelle. Thus, preoperative image examination is necessary in order to improve the success rate of surgery. Besides, the operation difficulty is associated with the shape of the upper nasal tube and its size. The less fold the natural channel has and the larger size the nasal tube has, the easier the operation is. When the angel of nasal upper tube is- 30°~0°, Upper tubesoften appear "^" form and drainage is simple. When it is 0°~60°, Upper tubes often appear "N" shape, "S" shape, etc.and drainage is difficult easily causing secondary infections in other sinus cavity. When it is 60°~120°, the maxillary sinus opening is funnel-shaped and nasal upper tube is absent, which is the best situation for drainage operation.