耳硬化症课件

Otosclerosis 2015-7-31 Otosclerosis vOtosclerosis is a disorder of the bony labyrinth and stapes affecting only humans. vIn 1735, the Italian anatomist and surgeon Antonio Maria Valsalva of Bologna was the first to report on the lesion Introduction v Autosomal dominant ：incomplete penetrance v Male : Female = 1 : 2 v Peak incidence in the second or third decade v 60% with family history v 10% of Caucasians with histologic findings， 12% have clinical symptoms. v One ear is affected, the other is involved 80% v Primarily conductive hearing loss， may be a sensorineural or mixed hearing loss Embryology vAt 8 weeks, the cartilaginous framework is begun. At 16 weeks, endochondral bony replacement of this framework. vThe fissula ante fenestram, anterior to oval window is the last area of endochondral bone formation. vThis region is affected in 8090% of patients Histopathology A: Active (Grade I) otosclerosis. Hypercellularity, intense basophilic staining and pseudo-vascular spaces filled by multinucleated osteoclasts and hyaline (white arrow) can be seen. Histopathology B: Otosclerosis with moderate activity (Grade II）. The pseudo- vascular spaces are widened and empty (white arrow). There is a marked thickening of the stapes footplate. The osteoid substance shows marked basophilia with hypercellularity. Histopathology C: Inactive (Grade III) otosclerosis.Osteoid substance shows eosinophilic staining and sparsely located osteocytes. Histopathology D: Burned out (Grade IV) otosclerotic focus with intense eosinophilic staining and acellular osteoid substance (white arrow). Otosclerosis-associated genes Although these loci have been mapped, we have little information regarding the role of these genes in disease development Immunohistologic research vThe lesions of otosclerosis may be isolated to the oval window or may involve the labyrinth more extensively vOtologists refer to either fenestral or retrofenestral (cochlear) otosclerosis. vPredilection for Otosclerosis Border of round window Apical medial wall of cochlear Area posterior to cochlear aqueduct Stapes footplate Diagnosis of Otosclerosis vHistory Slowly progressive hearing loss Hearing speech more easily in noisy situation Paracusis of Willis Tinnitus present in 75% Family history of OS PE 33(8): 13081314. Surgical Management v Stapedectomy since late 1950s. v Most otologists replace the stapes superstructure with a prosthesis， due to less chance of recurrence of fixation. v BAHA bypasses the ossicular chain and amplifies sound that stimulates the cochlea directly through bone conduction. v For those with severe to profound SNHL bilaterally due to OS, CI is an option. vImaging studies can confirm the clinical assumption of otosclerosis vIn this regard, high-resolution CT is the modality of choice for evaluating the labyrinthine windows, stapes footplate, cochlear capsule, and other inner ear structures Areas for the study of otosclerosis were divided into 3 zones,. Zone 1 is the area anterior to the oval window. Zone 2 is the pericochlear area. Zone 3 is the round window niche. Axial (a) and coronal(b) HRCT images of the right temporal bone in an adult patient with right-sided CHL. A hypodense demineralised plaque (arrow) is noted in the region of the fissula ante fenestram in keeping with fenestral otosclerosis Axial HRCT images of the right(a)and left(b) temporal bone in an adult patient with bilateral CHL. Hypodense demineralised plaques (arrows) are noted in bilateral fissula ante fenestram regions in keeping with bilateral fenestral otosclerosis Axial HRCT images of the right(a) and left(b)temporal bone in a patient with bilateral fenestral otosclerosis. Otosclerotic plaques are noted causing bilateral round window narrowing (arrows),right more than left left temporal bone in an adult patient with left-sided CHL and previous history of left-sided otitis media. The soft-tissue density noted in the attic (asterisk) causing blunting of the scutum (arrow) is in favour of a cholesteatoma. In addition, a tiny hypodense fenestral otosclerotic focus (arrowheads)is noted anterior to the oval window Axial (a)and coronal(b) HRCT images of the right temporal bone in a patient with stapedectomy. The radiodense stapes prosthesis is well positioned with its distal end against the oval window v Fenestral otosclerosis after stapedotomy. A, Axial CT image of the left ear shows a prosthesis (arrow) inserted into the oval window. Otosclerotic plaque is noted anterior to the oval window. B, Coronal CT image of the left ear demonstrates the prosthesis. Note that the end of the prosthesis protrudes minimally into the vestibule. Axial (a) and coronal(b) HRCT images of the left temporal bone in a patient with persistent CHL, post stapedectomy. The stapes prosthesis (arrow)is dislocated posteriorly in relation to the oval window (arrowhead) with complete loss of contact Para-axial HRCT image of the left temporal bone in a patient with severe vertigo, post stapedectomy. The stapes prosthesis is dislocated and lies partly within the vestibule (arrow) Para-coronal (a) and para-axial (b)HRCT of th left temporal bone in a patient with persistent vertigo and left-sided SNHL after left stapedectomy. The stapes prosthesis (arrow) is well positioned. However a small sclerotic focus is seen within the vestibule (arrowheads) in keeping with labyrinthitis ossificans. A small fenestral otosclerotic focus (dashed arrow) is seen in the para-axial view Axial HRCT images of the right(a) and left(b) temporal bone in an adult patient with severe bilateral SNHL. The bilateral pericochlear hypodense double ring(arrow) is in keeping with bilateral cochlear otosclerosis v A, Axial CT image shows pronounced demineralization (arrow) surrounding the cochlea. Note that the demineralization abuts the lumen in several places. B,Slightly inferior cut shows the demineralization of the otic capsule Coronal contrast-enhanced MR image in a patient with left-sided SNHL. Bilateral pericochlear ring-like enhancement (arrow) is suggestive of bilateral cochlear otosclerosis, which was further proven by HRCT A, Axial CT image shows the demineralization around the cochlea on either side. This gives the appearance of the double ring or fourth turn of the cochlea. B, Axial T2-weighted MR image shows the lumen of the cochlea but only a very faint hint of demineralization on the left side. aAxial HRCTof the right temporal bone in a patient with known bilateral cochlear otosclerosis. There is almost complete obliteration of the basal turn of the right cochlea (arrow) by the otosclerotic process.b Axial MRI of the temporal bones in the same patient as at the level of the cochlea. There is significant obliteration of the fluid space in the basal turn of the right cochlea (arrow). Fig. 15 Axial HRCT images of the right(a) and left(b) temporal bone in a young adult with known osteogenesis imperfecta tarda and bilateral SNHL. Bilateral pericochlear ring-like Hypodensity (arrows) closely mimics cochlear otosclerosis Axial (a) and coronal(b) HRCT images of the right temporal bone in a child with suspected left SNHL. The small lucency seen around the cochlea (arrow) on both the axial and coronal images is in keeping with a cochlear cleft (normal variant) Axial HRCT of the skull base in an adult patient with known Pagets disease. The hypodense appearance of bilateral otic capsules (arrows) may mimi