xem hào quang của áp xe subperiosteal quỹ đạo. Viêm trong mê cung hai xoang sàng thâm nhập vào papyracea phiến và bị mắc kẹt bên dưới vỏ xương quỹ đạo. Cơ rectus trung gian dày từ viêm và toàn cầu được di dời phía trước, sản xuất proptosis. | Endoscopic Ethmoidectomy and Antrostomy 333 Figure 13 16 Orbital preseptal cellulitis. Figure 13 17 Coronal view of orbital subperiosteal abscess. Inflammation in the ethmoid labyrinth penetrates the lamina papyracea and is trapped beneath the orbital periosteum. The medial rectus muscle is thickened from inflammation and the globe is displaced anteriorly producing proptosis. 334 Surgical Atlas of Pediatric Otolaryngology CYSTIC FIBROSIS Most children with cystic fibrosis have chronic sinusitis though many are asymptomatic. Clinically important disease falls into two categories 1 headache with chronic inflammatory changes and 2 polyposis with or without mucocele formation. Before endoscopic techniques intervention was restricted to children with massive polyposis and expansion of the nasal bones. In skilled hands however children with lesser degrees of symptomatic disease can benefit from endoscopic polypectomy if the following pointers are observed Pulmonary function should be optimized before surgery. Polyps usually fill the nasal cavity arising from the ethmoid cells and maxillary antra Figure 13 18 . Some of the anterior polyps must often be removed with a microdebrider before the uncinate process can be located. The uncinate is often demineralized floppy and rotated into the nasal cavity by protruding maxillary polyps. A microdebrider is used to remove the uncinate process. In contrast to the techniques above ethmoidectomy is performed before antrostomy because the maxillary sinus contents often bleed vigorously. Ethmoid polyps are removed in a controlled fashion with the microde-brider Figure 13 19 . Ethmoid mucoceles are occasionally encountered during polyp dissection marsupialization into the nose is curative. The natural ostium of the maxillary sinus is usually widely patent but filled with polyps. A curved microdebrider tip is used to remove polyps at the mouth of the maxillary antrum and to remove the soft tissue of the fontanelle Figure 13-20 . Figure
