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The Tullio phenomenon is an extremely rare condition in which loud noise induces a brisk vestibular response. Osteomas of the middle ear cleft are also uncommon. We report a patient with an osteoma of the middle ear cleft that became symptomatic with progressive facial palsy and mixed hearing loss. The onset was heralded by the Tullio phenomenon, which she had experienced for 10 years. The differential diagnosis of the Tullio phenomenon and the management of middle ear osteomas are discussed.
In 1929 Tullio first reported the association of nystagmus precipitated by loud noise.1 Initially reported as an observation in pigeons with abnormalities of the superior semicircular canals, the Tullio phenomenon has been reported in patients with various temporal bone abnormalities that have resulted in stapediovestibular coupling. Most importantly, this phenomenon can only happen when the tympanic membrane and ossicular chain are intact. This fact alone often obscures the diagnosis.
Only 23 patients with osteomas of the middle ear have been reported previously.2, 3, 4, 5, 6, 7, 8 , 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22 We present a patient with a middle ear osteoma associated with the Tullio phenomenon.
A 48–year–old woman sought treatment for a progressive right–sided facial palsy, which had developed over a period of 3 months, and for a hearing loss on the right that had been present for 2 years. In the weeks immediately before her presentation, she had become aware of intermittent otalgia and pulsatile tinnitus in her right ear.
Ten years earlier the patient had experienced the Tullio phenomenon and had undergone extensive investigation at another hospital. Based on her clinical records from that time, she had a 10–dB sensorineural hearing loss in her right ear. More detailed audiovestibular tests had shown that horizontal oscillopsia and vertigo could be elicited with 1200 Hz sound stimulation at 105 dB. Both computed tomography (CT) and magnetic resonance imaging (MRI) had failed to show any temporal bone abnormality. The conclusion was that her symptoms had been caused by a peripheral, but undefined, vestibular abnormality. Although her symptoms persisted, she pursued no further follow–up. During the ensuing years she continued to experience severe, brief episodes of rotatory vertigo that could be precipitated by loud traffic noise, the sound of children screaming, and straining or blowing her nose.
On examination her right tympanic membrane was intact, but a mass with a plum–colored hue seemed to be behind it in the attic. She had a grade 5 (House–Brackmann) right–sided facial palsy. First–degree horizontal nystagmus could be elicited when she gazed to the left, and she fell to the right when attempting the Unterberger test. Pure tone audiometry demonstrated an 80–dB mixed hearing loss in her right ear of which 30 dB was sensorineural. CT showed a calcified mass in the attic that had blocked the mastoid antrum and eroded the lateral semicircular canal (Fig. 1). The mastoid air cells were opaque and both T1– and T2–weighted MR sequences of this region were associated with a relatively high–intensity signal (Fig. 2).
The middle ear and mastoid were explored. The malleus, incus, and tympanic segment of the facial nerve were surrounded and fused in a calcified mass behind which cholesterol granuloma had developed (Fig. 3). A subtotal petrosectomy was performed, and the facial nerve was decompressed from the internal auditory meatus to the stylomastoid foramen (Fig. 4) The Eustachian tube and cochlear aqueduct were occluded with muscle and bone wax. A free fat graft harvested from the abdominal wall was used to obliterate the mastoid cavity. Histological examination of the middle ear mass revealed that it was an osteoma (Fig. 5).
Eight days elapsed before the patient was mobilized after surgery. She was fit for discharge on the thirteenth postoperative day. Three weeks later she was readmitted with cerebrospinal fluid (CSF) rhinorrhea. Lumbar CSF drainage was established and the leak ceased. During the ensuing months, her facial weakness and balance improved, and she returned to full–time employment. At review 18 months after surgery she had a grade 3 (House–Brackmann) facial weakness and exhibited only slight ataxia. However, she still reported a tendency to veer to the right.
The development of osteomas in the middle ear is rare. To date only 23 cases have been reported in the literature (Table 1).2, 3, 4, 5, 6, 7, 8 , 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22 Almost half of the reported osteomas have arisen from the promontory. The pyramidal process appears to be the next most common site of development. Where the osteoma arose in our patient was impossible to determine, but it may have originated from either the pyramidal process or the aditus and grew to encompass the ossicular chain. As might be expected, most osteomas in the middle ear have caused a pure conductive hearing loss, although they may be asymptomatic if there is no direct or indirect connection to the ossicular chain. Only one other case has been associated with a sensorineural component,17 but there was no evidence of labyrinthine erosion. The sensorineural hearing loss may be coincidental and caused by diabetic neuropathy.
Tullio observed that the vestibular system became sensitive to sound if a bony window was made in the superior semicircular canal.1 Hence, the term “Tullio phenomenon” is applied to patients who exhibit vestibular activation in response to acoustic stimulation.23 In these patients, intense sound produces vertigo, imbalance, or oscillopsia. A few may experience similar symptoms while straining or when pressure is applied to the tragus. This phenomenon has been reported in a range of conditions, including fistulae of the lateral semicircular canal,24, 25, 26 the Mondini developmental abnormality,26, 27 endolymphatic hydrops,28 and the hypermobile stapes syndrome.29 It has never been reported previously in association with a middle ear osteoma. In our patient, the lateral semicircular canal had been eroded by the osteoma and obviously had not sealed, even though no overt fistula was seen at exploration.
Only 6 of the 23 cases of middle ear osteoma have been in women; most have been found in young men. The age at presentation has varied from 5 to 57 years. A single report documents middle ear osteomas in siblings and proposed a genetic predisposition.2 No other related cases have been found.
No other patient has presented with progressive facial weakness. In our patient, the facial weakness was likely caused by interruption or compression of the blood supply to the tympanic segment of the facial nerve. The differential diagnosis for a bony tumor in this position also should include ossifying hemangiomas, which have been reported within the middle ear in relation to the facial nerve.30 As in other situations in which facial nerve function is compromised by extrinsic pressure, good outcomes can be achieved by prompt decompression. Recovery of the facial nerve was probably incomplete in our patient because several months elapsed before she sought treatment. Decompression of the facial nerve can be restricted to limited sections of the Fallopian canal. However, in our patient, it seemed sensible to uncover the entire nerve because the entire labyrinth had to be removed. This maneuver also ensured that no viable sensory neuroepithelium remained that might interfere with subsequent vestibular compensation.