1
Introduction
Pneumolabyrinth as a radiologic sign of a perilymphatic fistula was first reported by Mafee et al shortly after the invention of high-resolution computed tomography (HRCT). The intrusion of air into the inner ear has been described as a complication of petrous bone fractures mostly after direct manipulative trauma to the tympanic membrane, often in combination with a displacement of the stapes into the vestibule . It has also been reported as an iatrogenic complication after stapes surgery, particularly after a stapedectomy .
We report a case of a radiologically confirmed pneumolabyrinth presumably as a consequence of a strong sneeze in a patient with large vestibular aqueduct syndrome (LVAS). In addition, the patient wears a cochlear implant on the same side. In a theoretical approach, we discuss the probability of the cochleostomy, the LVAS, or an interaction of both being the cause for the pneumolabyrinth.
2
Case report
A 50-year-old woman presented with progressive hearing loss on both sides since childhood that had to be treated with hearing aids at the age of 4 years. Familial history for amblyacousia was empty; there has been neither trauma nor treatment with ototoxic drugs in the past. There was no history or evidence on clinical examination of neurologic malformations, neurosurgical procedures, recurrent middle ear inflammation, or rare entities like Alport or Usher syndrome.
On the right side, the patient subsequently suffered deafness over the past 7 years. On the left side, she showed a high-grade sensorineural hearing loss where the use of conventional hearing aids led to no improvement in speech recognition. A preoperative HRCT showed large vestibular aqueducts on both sides; furthermore, there was no evidence of ossification on either side, with normal imaging result of the outer and middle structures. The usual preoperative diagnostics that included a promontorial test showed no contraindications; and thus, we indicated a cochlear implantation with a COCHLEAR Nucleus Freedom (Hannover, Germany) implant on the right side. The postoperative course was uneventful; the transorbital temporal bone imaging showed a correct position of the electrodes.
After 6 months, there was a significant improvement in hearing and speech recognition; simultaneously, the patient reported progressive, fluctuating vertigo that led to a significant impairment during work and off time. She noticed an odd bubbling sound on the right ear that started after a strong sneeze; in addition, she had the feeling as if the environment was consistently moving around her. At this time, pain was negated, tinnitus did not change its intensity or frequency, there was no fever and no clinical evidence for meningism, and the inflammation parameters were normal. Valance function tests with Frenzel glasses showed no spontaneous or provoked nystagmus. The Romberg sign and the Unterberger stepping test showed a slight tendency to fall backward; thermal testing of the horizontal semicircular duct could not be accomplished because of noncompliance due to early vomiting. A probatory intravenous hydration with hydroxyethyl starch, pontocain, and dexamethasone resulted in a particular relief.
After another month, the formerly pleasing grade of speech recognition lowered gradually. In the Hochmair-Schulz-Moser (HSM) sentence test, the identification rate declined from 80% to 47%. Average pure-tone thresholds dropped to 60 to 80 dB from 250 to 6000 Hz ( Fig. 1 ). Therefore, we performed an HRCT scan that showed an inflation of air into the right basal coil of the cochlea, the vestibular system in the region of the utricle and saccule, and the endolymphatic sac ( Fig. 2 ).
Under the assumption of a perilymphatic fistula in the area of the cochleostomy, we performed revision surgery on the right side and applied a thin layer of soft tissue over the cochleostomy site. During surgery, no perilymphatic fistula could be observed. In addition, we inserted a grommet into the tympanic membrane. The rationale was to incapacitate the patient doing Valsalva-like maneuvers, like sneezing, and hereby prevent the middle ear from positive pressure. In the consecutive months, the vertigo diminished; and the patient showed a progress in speech recognition (HSM sentence test recognition rate of 92%) and in pure-tone audiometric results to preoperative values ( Fig. 3 ). An HRCT control showed a complete remission of the pneumolabyrinth ( Fig. 4 ). Follow-up is still closely monitored; and to this day, no similar event has taken place.
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