Abstract:The proposed classification for round window otosclerosis is a valuable clinical tool that can help in decisions regarding, and counseling about, stapes surgery. Classes RW-I and RW-II have no clinical impact. Patients with RW-III otosclerosis may have a mild residual gap after surgery; those with RW-IV have dramatically poorer results.
“…This rarely is associated with secondary torsional subluxation of the incus [2]. Otosclerosis can sometimes present as isolated round window involvement without pericochlear or oval window involvement [6]. Fig.…”
Otosclerosis is an otodystrophy of the otic capsule and is a cause of conductive, mixed or sensorineural hearing loss in the 2nd to 4th decades of life. Otosclerosis is categorised into two types, fenestral and retrofenestral. Imaging plays an important role in the diagnosis and management of otosclerosis. High-resolution CT (HRCT) of the temporal bone using 1-mm (or less) thick sections is the modality of choice for assessment of the labyrinthine windows and cochlear capsules. MRI has limited application in the evaluation of the labyrinthine capsules but is useful for assessment of the cochlear lumen prior to cochlear implantation in patients with profound hearing loss. The treatment of fenestral otosclerosis is primarily surgical with stapedectomy and prosthesis insertion. Patients with retrofenestral otosclerosis and profound hearing loss are treated medically using fluorides, but may derive significant benefit from cochlear implantation. This pictorial review aims to acquaint the reader with the pathology and clinical features of otosclerosis, the classical imaging appearances on CT and MRI, a radiological checklist for preoperative CT evaluation of otosclerosis, imaging mimics and a few examples of post-stapedectomy imaging and complications.Teaching points• Otosclerosis causes conductive, sensorineural and mixed hearing loss in adults.• HRCT of the temporal bone is the diagnostic imaging modality of choice.• Stapedectomy is used to treat fenestral otosclerosis.• Fluorides and cochlear implantation are used to treat retrofenestral otosclerosis.
“…This rarely is associated with secondary torsional subluxation of the incus [2]. Otosclerosis can sometimes present as isolated round window involvement without pericochlear or oval window involvement [6]. Fig.…”
Otosclerosis is an otodystrophy of the otic capsule and is a cause of conductive, mixed or sensorineural hearing loss in the 2nd to 4th decades of life. Otosclerosis is categorised into two types, fenestral and retrofenestral. Imaging plays an important role in the diagnosis and management of otosclerosis. High-resolution CT (HRCT) of the temporal bone using 1-mm (or less) thick sections is the modality of choice for assessment of the labyrinthine windows and cochlear capsules. MRI has limited application in the evaluation of the labyrinthine capsules but is useful for assessment of the cochlear lumen prior to cochlear implantation in patients with profound hearing loss. The treatment of fenestral otosclerosis is primarily surgical with stapedectomy and prosthesis insertion. Patients with retrofenestral otosclerosis and profound hearing loss are treated medically using fluorides, but may derive significant benefit from cochlear implantation. This pictorial review aims to acquaint the reader with the pathology and clinical features of otosclerosis, the classical imaging appearances on CT and MRI, a radiological checklist for preoperative CT evaluation of otosclerosis, imaging mimics and a few examples of post-stapedectomy imaging and complications.Teaching points• Otosclerosis causes conductive, sensorineural and mixed hearing loss in adults.• HRCT of the temporal bone is the diagnostic imaging modality of choice.• Stapedectomy is used to treat fenestral otosclerosis.• Fluorides and cochlear implantation are used to treat retrofenestral otosclerosis.
“…Tympanosclerotic plaques are found in the attic and around the stapes, oval window, RW, and promontorium [3]. The second most common site for sclerosis occurrence is the RW region, which is involved in 30% of clinical cases in histologic studies [4]. In radiologic studies, the prevalence of sclerosis in the RW is 3.2–13% [4].…”
Section: Discussionmentioning
confidence: 99%
“…The second most common site for sclerosis occurrence is the RW region, which is involved in 30% of clinical cases in histologic studies [4]. In radiologic studies, the prevalence of sclerosis in the RW is 3.2–13% [4]. Half of the patients with tympanosclerosis have required second sessions or revision procedures if ossicle fixation was present [5].…”
Usage of the Vibrant Soundbridge (VSB) with round window (RW)-Coupler placement at the RW has been shown to successfully treat mixed hearing loss. Coupling between the VSB's floating mass transducer (FMT) and the RW membrane is difficult in the case of sclerosis in the RW and drilling down the bony lip until the RW membrane can be seen completely can possibly induce a perilymphatic fistula. A 68-year-old woman who had bilateral mixed hearing loss with sclerosis in the RW due to tympanosclerosis underwent a RW-Vibroplasty with a RW-Coupler. Speech discrimination scores in quiet and noise and functional gain with the VSB with RW-Coupler were better than those using a conventional hearing aid. The results of the present case have shown the feasibility of implanting a VSB with RW-Coupler in patients with mixed hearing loss due to tympanosclerosis.
“…30,31 Fenestral otosclerosis may also secondarily involve the round window in approximately 3%-13% of cases. 32,33 Isolated round window otosclerosis has been reported, though the prevalence is rare (approximately 0.3% of cases). 32 Nevertheless, secondary involvement or isolated involvement of the round window by otosclerosis is an important radiologic observation because it portends a poorer chance of surgical success.…”
Section: Acquired Abnormalitiesmentioning
confidence: 99%
“…32,33 Isolated round window otosclerosis has been reported, though the prevalence is rare (approximately 0.3% of cases). 32 Nevertheless, secondary involvement or isolated involvement of the round window by otosclerosis is an important radiologic observation because it portends a poorer chance of surgical success. 30 Specifically, round window involvement diminishes the movement of perilymphatic fluid following stapedectomy and prothesis placement, the surgery typically used in cases of otosclerosis.…”
The round window serves to decompress acoustic energy that enters the cochlea via stapes movement against the oval window. Any inward motion of the oval window via stapes vibration leads to outward motion of the round window. Occlusion of the round window is a cause of conductive hearing loss because it increases the resistance to sound energy and consequently dampens energy propagation. Because the round window niche is not adequately evaluated by otoscopy and may be incompletely exposed during an operation, otologic surgeons may not always correctly identify associated pathology. Thus, radiologists play an essential role in the identification and classification of diseases affecting the round window. The purpose of this review is to highlight the developmental, acquired, neoplastic, and iatrogenic range of pathologies that can be encountered in round window dysfunction.
ABBREVIATIONS: LO 4 labyrinthitis ossificans; RW 4 round windowIndicates open access to non-subscribers at www.ajnr.org http://dx.
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