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Migration of intradural epidermoid matrix: Embryological implications
OtolaryngoiogyHead and Neck Surgery Volume 121 N u m b e r 2
Objectives: Superior semicircular canal (SSC) dehiscence is a recently described clinical entity associated with sound, positional, and pressure-induced nystagmus and vertigo. The bony covering of the canal in the middle cranial fossa is absent, leading to pressure transduction from the intracranial space. This study evaluates the prevalence of SSC dehiscence on CT imaging of the temporal bone and correlates these findings with clinical symptoms. Methods: The high-resolution temporal bone CT scans of 30 consecutive adults and 30 consecutive children were evaluated for presence and extent of SSC dehiscence. The patients then completed an extensive telephone survey characterizing any otologic symptoms. The prevalence of SSC dehiscence in our patient population was calculated, and the results of the survey were correlated with the CT findings. Results: Based on CT parameters, 12 of 60 (20%) patients, 6 each of adults and children, demonstrated SSC dehiscence. Of the adults with dehiscence 4 (67%) had vertigo compared with 9 of 24 (38%) of those without dehiscence. Only one child had vertigo, and this patient did not have SSC dehiscence. The size of the dehiscence did not correlate with the severity of symptoms. Of vertiginous adults 4 of 13 (31%) had SSC dehiscence compared with nonvertiginous adults, in whom only 2 of 17 (12%) had SSC dehiscence. Conclusion: In a selected population, those undergoing CT imaging of the temporal bone, 20% of adults and children, have SSC dehiscence, making it a relatively common finding. Two thirds of adults with this finding had vertigo. SSC dehiscence is a potentially reparable cause of vertigo in the adult population; therefore high-resolution CT imaging of the temporal bone should be considered in the vertiginous patient. 10:02 AM
Migration of Intradural Epidermoid Matrix: Embryological Implications STILIANOS E KOUNTAKIS MD PHD (presenter); C Y JOSEPH CHANG MD; WILLIAM GHORMLEY MD; FERNANDO R CABRAL PHD; Houston TX
Objectives: The in vitro migratory behavior of acquired cholesteatoma matrices (those arising from the tympanic membrane) has been described previously. This tissue is derived embryologically from the first branchial groove and represents the only migratory epithelium arising from the branchial groove system. Epidermoid tumors isolated to the cerebellopontine angle are rare entities whose embryologic origin is presumed to be rests of ectodermal tissue that become trapped within the neural tube prior to neural tube closure. If the matrix from such an epidermoid exhibits migratory behavior similar to that of cholesteatomas originating from the tympanic membrane, a first branchial groove site of origin for cerebellopontine angle epidermoids would be supported.
Scientific Sessions--Tuesday
P161
Methods: Epidermoid cells harvested from a patient with histologically proven epidermoid tumor of the cerebellopontine angle without any evidence of extradural involvement were grown in tx-minimum essential medium. The cultures were examined daily, and cell mass migration rates were measured. Results: Cell mass migration was observed in vitro in the epithelial cells harvested from the cerebellopontine angle. The pattern of migration was similar to that seen in cells harvested from the medial external auditory canal, tympanic membrane, and acquired cholesteatomas. Conclusion: An exclusively intradural epidermoid tumor matrix harvested from the cerebellopontine angle exhibited migration in vitro. Its migratory properties were indistinguishable from those of matrices harvested from the medial external auditory canal, tympanic membrane, and acquired cholesteatomas, which are embryologically derived from the first branchial groove. These data provide support that purely intradural epidermoids are derived from cells of the first branchial groove. 10:10 AM
Hearing Lossin Steel Band Players SOLAIMAN JUMAN MD MBBS FRCS (presenter); COLLINS KARMODY MD; DONALD SIMEON; Couva Trinidad & Tobago; Boston MA; Mt Hope Trinidad & Tobago
Objectives: The steel pan was invented in Trinidad and is an integral part of the Trinidad culture. Sound pressure levels in a steel band can be quite high and have the potential for causing noise-induced hearing loss. This study compares the hearing of a group of steel band players to that of a group of non-steel-pan-playingcontrols. Methods: Thirty volunteers from a steel band in East Trinidad and thirty non-steel-band-playingcontrols had their hearing tested. A questionnaire was administered, and any steel band players with a history of ear disease were excluded. A similar questionnaire was filled out by the controls, and any one with previous exposure to noise was excluded. All the subjects were examined to exclude any anatomical abnormalities. Hearing levels at 250, 500, 100, 2000, 3000, 4000, 6000, and 8000 Hz were measured. Results: There was a statistically significant difference between the 2 groups at 2 (P < 0.02), 3, 4, and 6 kHz (P < 0.01). In all subjects older than 40 years, the steel band players were significantly worse than the controls at 3, 4, and 6 kHz (P < 0.001). The longer a steel band player played the instrument, there was a statistically significant trend toward having a hearing loss at 2 (P < 0.04), 3, 4 (P < 0.05), 6 (P < 0.03), and 8 kHz (P < 0.02). Conclusion: Steel band players suffer permanent auditory injury from prolonged exposure to loud sound. This clearly indicates a need for preventative measures to be instituted to prevent this from occurring in these musicians.
Objectives: Superior semicircular canal (SSC) dehiscence is a recently described clinical entity associated with sound, positional, and pressure-induced nystagmus and vertigo. The bony covering of the canal in the middle cranial fossa is absent, leading to pressure transduction from the intracranial space. This study evaluates the prevalence of SSC dehiscence on CT imaging of the temporal bone and correlates these findings with clinical symptoms. Methods: The high-resolution temporal bone CT scans of 30 consecutive adults and 30 consecutive children were evaluated for presence and extent of SSC dehiscence. The patients then completed an extensive telephone survey characterizing any otologic symptoms. The prevalence of SSC dehiscence in our patient population was calculated, and the results of the survey were correlated with the CT findings. Results: Based on CT parameters, 12 of 60 (20%) patients, 6 each of adults and children, demonstrated SSC dehiscence. Of the adults with dehiscence 4 (67%) had vertigo compared with 9 of 24 (38%) of those without dehiscence. Only one child had vertigo, and this patient did not have SSC dehiscence. The size of the dehiscence did not correlate with the severity of symptoms. Of vertiginous adults 4 of 13 (31%) had SSC dehiscence compared with nonvertiginous adults, in whom only 2 of 17 (12%) had SSC dehiscence. Conclusion: In a selected population, those undergoing CT imaging of the temporal bone, 20% of adults and children, have SSC dehiscence, making it a relatively common finding. Two thirds of adults with this finding had vertigo. SSC dehiscence is a potentially reparable cause of vertigo in the adult population; therefore high-resolution CT imaging of the temporal bone should be considered in the vertiginous patient. 10:02 AM
Migration of Intradural Epidermoid Matrix: Embryological Implications STILIANOS E KOUNTAKIS MD PHD (presenter); C Y JOSEPH CHANG MD; WILLIAM GHORMLEY MD; FERNANDO R CABRAL PHD; Houston TX
Objectives: The in vitro migratory behavior of acquired cholesteatoma matrices (those arising from the tympanic membrane) has been described previously. This tissue is derived embryologically from the first branchial groove and represents the only migratory epithelium arising from the branchial groove system. Epidermoid tumors isolated to the cerebellopontine angle are rare entities whose embryologic origin is presumed to be rests of ectodermal tissue that become trapped within the neural tube prior to neural tube closure. If the matrix from such an epidermoid exhibits migratory behavior similar to that of cholesteatomas originating from the tympanic membrane, a first branchial groove site of origin for cerebellopontine angle epidermoids would be supported.
Scientific Sessions--Tuesday
P161
Methods: Epidermoid cells harvested from a patient with histologically proven epidermoid tumor of the cerebellopontine angle without any evidence of extradural involvement were grown in tx-minimum essential medium. The cultures were examined daily, and cell mass migration rates were measured. Results: Cell mass migration was observed in vitro in the epithelial cells harvested from the cerebellopontine angle. The pattern of migration was similar to that seen in cells harvested from the medial external auditory canal, tympanic membrane, and acquired cholesteatomas. Conclusion: An exclusively intradural epidermoid tumor matrix harvested from the cerebellopontine angle exhibited migration in vitro. Its migratory properties were indistinguishable from those of matrices harvested from the medial external auditory canal, tympanic membrane, and acquired cholesteatomas, which are embryologically derived from the first branchial groove. These data provide support that purely intradural epidermoids are derived from cells of the first branchial groove. 10:10 AM
Hearing Lossin Steel Band Players SOLAIMAN JUMAN MD MBBS FRCS (presenter); COLLINS KARMODY MD; DONALD SIMEON; Couva Trinidad & Tobago; Boston MA; Mt Hope Trinidad & Tobago
Objectives: The steel pan was invented in Trinidad and is an integral part of the Trinidad culture. Sound pressure levels in a steel band can be quite high and have the potential for causing noise-induced hearing loss. This study compares the hearing of a group of steel band players to that of a group of non-steel-pan-playingcontrols. Methods: Thirty volunteers from a steel band in East Trinidad and thirty non-steel-band-playingcontrols had their hearing tested. A questionnaire was administered, and any steel band players with a history of ear disease were excluded. A similar questionnaire was filled out by the controls, and any one with previous exposure to noise was excluded. All the subjects were examined to exclude any anatomical abnormalities. Hearing levels at 250, 500, 100, 2000, 3000, 4000, 6000, and 8000 Hz were measured. Results: There was a statistically significant difference between the 2 groups at 2 (P < 0.02), 3, 4, and 6 kHz (P < 0.01). In all subjects older than 40 years, the steel band players were significantly worse than the controls at 3, 4, and 6 kHz (P < 0.001). The longer a steel band player played the instrument, there was a statistically significant trend toward having a hearing loss at 2 (P < 0.04), 3, 4 (P < 0.05), 6 (P < 0.03), and 8 kHz (P < 0.02). Conclusion: Steel band players suffer permanent auditory injury from prolonged exposure to loud sound. This clearly indicates a need for preventative measures to be instituted to prevent this from occurring in these musicians.