tailieunhanh - Ear Surgery - part 4

Các biến chứng thường gặp nhất của viêm tai giữa mạn tính (COM) extracranial labyrinthitis và tê liệt thần kinh mặt. Labyrinthitis có liên quan với COM xảy ra thông qua fistulization viên OTIC cuộc xâm lược thông qua các cửa sổ hình bầu dục tròn. Loại bỏ các màng cholesteatoma từ màng endosteal được khuyến khích. | 4 Complications of Chronic Otitis Media Z Core Messages The most common extracranial complications of chronic otitis media COM are labyrinthitis and facial nerve paralysis. Labyrinthitis associated with COM occurs through fistulization of the otic capsule or invasion through the oval and round windows. Removal of cholesteatoma membrane from the endosteal membrane is recommended. Repair of oval or round window defects with soft tissue is an effective technique to preserve labyrinth function. Facial nerve paralysis in COM requires early surgery to remove chronic disease and preserve facial function. Intracranial complications from COM include meningitis brain abscess epidural subdural abscess and sigmoid sinus thrombophlebitis. Meningitis and brain abscess from COM may occur through a preformed pathway or by retrograde thrombophlebitis. The most serious complications of untreated COM and mastoiditis are labyrinthitis facial paralysis and various intracranial complications. The main intracranial complications are meningitis brain abscess subdural or epidural abscess and lateral sigmoid sinus thrombophlebitis. Extracranial Complication Labyrinthitis Labyrinthitis or invasion of the perilymphatic space by chronic middle ear and mastoid disease occur over three pathways. These are 1 fistulization of the bony labyrinth 2 round window and 3 oval window. The most common of the pathways is bony erosion of the labyrinthine capsule usually of the semicircular canals but less often of the bony wall of the cochlea. This bone erosion occurs as a result of the effects of pressure from an enlarging cholesteatoma and or the chemical breakdown of collagen by collagenase enzymes in the cholesteatoma membrane 1 Fig. . o Fig. A schematic demonstration of stages in bone erosion by cholesteatoma. BL bony labyrinth EB endosteal bone M membranous canal EM endosteal membrane P perilymph 34 Chapter 4 Complications of Chronic Otitis Media Fig. Axial CT of a temporal bone