The Relation between Mastoid Pneumatization and Sigmoid Sinus Position in Chronic Otomastoiditis

PURPOSE: If significantly influenced by chronic otomastoiditis(COM), mastoid pneumatization and the position of the sigmoid sinus affect the operative procedure and postoperative complications in middle ear surgery. We evaluated mastoid pneumatization and sigmoid sinus position, and their relationship in COM, especially its during onset. MATERIALS AND METHODS: Using temporal bone CT and referring to any relevant medical records, we retrospect+tively analyzed 107 cases of COM and 49 cases of normal ear. The total case load comprised an adult group, aged above 16 years [100 cases of COM (M:F=46:54, mean age = 45 years), and 42 cases of normal ear,(M:F=20:22, mean age = 44 years)], and a childhood group, aged less than 16 years [7 cases of COM (M:F=4:3, mean age = 8.4 years), and 7 cases of normal ear (M:F=4:3, mean age = 7 years)]. We determined the thickness of the mastoid bone by measuring the shortest distance between the outer cortex of this bone and the deepest border of the sigmoid sinus; the depth of the sigmoid sinus; and the degree of mastoid pneumatization and sclerosis. Fifty-three patients whose medical history clearly included the onset of otomas-toiditis were divided into a child-onset group and an adult-onset group, and the relationship between the onset of otomastoiditis and the thickness of the mastoid bone was compared between the two groups. RESULTS: The mean axial thickness of the mastoid bone was 9.672 <+/-2.745 mm in COM and 12.430 +/-3.027 mm in normal ear. The difference was statisfically significant (p < 0.0001). The mean depth of the sigmoid sinus was 7.557 +/-1.868 mm in COM and 7.591 +/-2.315 mm in normal ear, with no statistically significant difference. In the childhood group, the mean axial thickness of the mastoid bone was 8.672 +/-2.978 mm in COM and 11.778 +/-3.087 mm in normal ear. This difference was statistically significant (p < 0.05). In the adult group, the corresponding figures were 9.742 +/-2.731 mm in COM and 12.538 +/-3.041 mm in normal ear, a dif-ference which was also statistically significant (p < 0.0001). Among patients with an obvious history of COM, child-onset cases totalled 24 (mean axial thickness of the mastoid bone, 9.2.0 +/-2.158 mm), while there were 29 adult-onset cases (mean axial thickness, 10.08 +/-2.99 mm). This difference in thickness between child-onset and adult-onset COM was statistically significant (p < 0.05). CONCLUSION: In COM, the degree of mastoid pneumatization is proportional to the axial thickness of the mastoid bone, and inversely proportional to the degree of sclerosis, anterior location of the sigmoid sinus and the onset of COM. If the sigmoid sinus is properly located, COM may inhibit mastoid pneumatization.

Differential Diagnosis between Chronic Otitis Media with and Mass Effect

PURPOSE: In order to determine specific differences, we compared the temporal bone CT findings of chronic otitis media(COM) with and without cholesteatoma, focusing on bone change. MATERIALS AND METHODS: Between 1997 and 1998, 82 patients(84 cases) underwent temporal bone CT and were shown to have COM, with or without cholesteatoma after mastoidectomy and tympanoplasty. There were 36cases of COM with cholesteatoma(26 patients, M:F=11:15; age range, 16 -61 [mean, 36.2] years), and 58 cases without cholesteatoma(56 patients, M:F=25:31, age range, 15 -61 [mean, 36.2]years). The findings of temporal bone CT were analyzed at the point of bony changes including erosion and medial displacement of ossicles(malleus, incus, and stapes), erosion or destruction of the scutum, tegmen, facial canal, and lateral semicircular canal, and ballooning of the tympanic cavity and mastoid antrum. In addition, the soft tissue changes seen on temporal bone CT were analyzed at the site of lateral bulging of soft tissue in Prussak's space, perforation of the pars flaccida, tympanic membrane retraction, and tympanosclerosis. We retrospectively compared the findings of temporal bone CT with the surgical findings, and to assess statistical significance, the Chi-square test was used. RESULTS: Bone erosion or destruction was seen in 36.2 % of COM cases without cholesteatoma, and in 96.2% of cases with cholesteatoma. Comparing COM with and without cholesteatoma, the erosion of ossicles includ-ing the malleus(81%, 24%), incus(88%, 14%), stapes(58%, 10%), scutum(88%, 10%), facial canal(8%, 0%), and lateral semicircular canal(8%, 0%), was more common in COM with cholesteatoma(p-value0.05). CONCLUSION: Bone erosion or destruction was seen in COM without cholesteatoma, but expansile bone erosion or destruction with mass effect suggested COM with cholesteatoma. These findings of temporal bone CT in COM demonstrate the existence and extent of combined cholesteatoma, and are therefore valuable.

Differential Diagnosis between Chronic Otitis Media with and Mass Effect

PURPOSE: In order to determine specific differences, we compared the temporal bone CT findings of chronic otitis media(COM) with and without cholesteatoma, focusing on bone change. MATERIALS AND METHODS: Between 1997 and 1998, 82 patients(84 cases) underwent temporal bone CT and were shown to have COM, with or without cholesteatoma after mastoidectomy and tympanoplasty. There were 36cases of COM with cholesteatoma(26 patients, M:F=11:15; age range, 16 -61 [mean, 36.2] years), and 58 cases without cholesteatoma(56 patients, M:F=25:31, age range, 15 -61 [mean, 36.2]years). The findings of temporal bone CT were analyzed at the point of bony changes including erosion and medial displacement of ossicles(malleus, incus, and stapes), erosion or destruction of the scutum, tegmen, facial canal, and lateral semicircular canal, and ballooning of the tympanic cavity and mastoid antrum. In addition, the soft tissue changes seen on temporal bone CT were analyzed at the site of lateral bulging of soft tissue in Prussak's space, perforation of the pars flaccida, tympanic membrane retraction, and tympanosclerosis. We retrospectively compared the findings of temporal bone CT with the surgical findings, and to assess statistical significance, the Chi-square test was used. RESULTS: Bone erosion or destruction was seen in 36.2 % of COM cases without cholesteatoma, and in 96.2% of cases with cholesteatoma. Comparing COM with and without cholesteatoma, the erosion of ossicles includ-ing the malleus(81%, 24%), incus(88%, 14%), stapes(58%, 10%), scutum(88%, 10%), facial canal(8%, 0%), and lateral semicircular canal(8%, 0%), was more common in COM with cholesteatoma(p-value0.05). CONCLUSION: Bone erosion or destruction was seen in COM without cholesteatoma, but expansile bone erosion or destruction with mass effect suggested COM with cholesteatoma. These findings of temporal bone CT in COM demonstrate the existence and extent of combined cholesteatoma, and are therefore valuable.

Temporal Bone CT Findings of Tuberculous Otitis Media: Comparison with Chronic Otitis Media

PURPOSE: To compare the differential findings of tuberculous otitis media(TOM) with those of chronic suppurative otitis media with or without cholesteatoma, as seen on high resolution temporal bone CT. MATERIALS AND METHODS: We retrospectively reviewed 14 cases of TOM, 30 cases of chronic suppurative otitis media(CSOM), and 30cases of chronic otitis media with cholesteatoma(Chole). All had been pathologically confirmed. We evaluated thepreservation of mastoid cells without sclerotic change, the location and extension of soft tissue to the externalauditary canal, the erosion of ossicles, the tegmen tympani, scutum, bony labyr inth, facial nerve canal andsigmoid sinus, and the presence of intracranial co mplications. RESULTS: Soft tissue in the mastoid antrum wasseen in all cases of TOM(100%), 29 cases of CSOM(96.7%), and 26 cases of Chole(86.7%). In contrast, the softtissue in the entire middle ear cavity was noted in 13 cases of TOM(92.8%), 7 cases of CSOM(23.3%), and 12 casesof Chole(40%). Soft tissue extended to the superior aspect of the external auditory canal in 4 cases of TOM(28.6%) and 5 cases of Chole (16.7%). Mastoid air cells were seen in 9 cases of TOM (64.3%), 4 cases of CSOM(13.3%), and 3 cases of Chole(10%). Ossicular erosion was noted in 6 cases of TOM (42.9%), 12 cases of CSOM (40%),and 26 cases of Chole(86.7%), while in one case of TOM (7.1%), 5 cases of CSOM (16.7%), and 15 cases of Chole(50%)there was erosion of the scutum. In one case of TOM, follow-up CT study after 9 months of antituberculousmedication without surgery revealed complete clearing of previously noted soft tissue in the middle ear cavity. CONCLUSION: Specific CT findings of TOM were not seen, but if there were findings of soft tissue in the entiremiddle ear cavity, soft tissue extension to the external auditory canal, preservation of mastoid air cells withoutsclerotic change, and intact scutum, TOM may be differentiated from other chronic otitis media.

Three Cases of Tuberculous Otitis Media

We report the imaging features of three cases of tuberculous otitis media. All three patients underwenttemporal bone CT scanning, and in two, additional MRI scanning was performed. The three cases showed soft tissuedensity in the external auditory canal, and in two, destruction of the trabeculation and internal cortex of themastoid bone was noted. In two patients with facial palsy, erosion of the facial canal was seen. On MRI, abundantgranulomatous tissue was noted in the middle ear cavity and mastoid air cells. In one case, abnormal enhancementof the cochlea, and of the facial and eighth cranial nerve in the internal acoustic canal was seen. Another caseshowed enhancement of the vestibule and lateral semicircular canal. If radiologic evaluation of chronic otitismedia reveals destruction of the tegmen and trabeculation of the mastoid bone, together with abundant granulationtissue and enhancement of the internal ear, tuberculous otitis media may be included in the differentialdiagnosis.