Pneumolabyrinth: a systematic review

PURPOSE

The aim of this study is to provide a systematic review of the literature about the etiology, clinical and radiological presentation, surgical management, and outcomes of pneumolabyrinth (PNL).

METHODS

A systematic review of the literature was performed including studies published up to September 2020 in electronic databases (PubMed/MEDLINE, EMBASE, Cochrane Library, and Scopus). The PRISMA standard was applied to identify English, Italian, or French-language studies mentioning PNL. Full texts lacking information on the etiology were excluded. Data concerning the cause, site of air bubbles/fistula, clinical presentation, treatment, and outcome were collected. A qualitative synthesis of the results was performed.

RESULTS

Seventy-eight articles were eventually included; 132 patients were involved in the qualitative synthesis. The most common causes were: stapes surgery (24/132, 18.2%), temporal bone fracture (42/132, 31.8%), head trauma without temporal bone fracture (19/132, 14.4%), penetrating trauma (21/132, 15.9%), and barotrauma (15/132, 11.4%). The site most commonly involved was the vestibule (102/107, 95.3%), followed by cochlea (43/107, 40.2%) and semicircular canals (25/107, 23.4%).

CONCLUSION

The etiopathogenesis of PNL can be summarized in traumatic, iatrogenic, or inflammatory/infective. Its management consists in exploratory tympanotomy and sealing the fistula, but also conservative treatments can be attempted. Vestibular symptoms disappear in the majority of cases. Instead, the prognosis of hearing function is widely variable, and complete recovery is less probable. The certainty of evidence is still too low to make it useful for clinical decision-making.

Post-traumatic pneumolabyrinth: a rare cause of hearing loss

Pneumolabyrinth (PL) is the presence of air within the vestibule, semicircular canals, or cochlea. It represents an abnormal connection between the inner ear and middle ear spaces. PL most commonly occurs after blunt head trauma, followed by penetrating injuries. Temporal fractures may or may not accompany. Prognosis of hearing loss is poor, while prognosis of vestibular symptoms is good. Herein we present a 45-year-old female with unilateral pneumolabyrinth, who presented with significant dizziness and unilateral total hearing loss after a car accident.

Pneumolabyrinth, intracochlear and vestibular fluid loss after cochlear implantation

The present case was a 38-year-old male who presented with progressive hearing loss, resulting in profound bilateral hearing loss. He had a past history of childhood medulloblastoma, which was treated with posterior fossa craniotomy and radiotherapy. A ventriculoperitoneal (VP) shunt was put in place to manage the hydrocephalus. Cochlear implantation (CI) was carried out on his right ear by a standard procedure. At CI activation, the electric impedance of the electrode was very high, and computed tomography revealed that there was no area of liquid density, suggesting depletion of the perilymph in the cochlea and vestibule. Eight months later, the impedance improved gradually, and the cochlea was filled with perilymph. Consequently, one of the causes of the pneumolabyrinth in the present case was that a scarred stenotic cochlear canaliculus secondary to surgery or radiation therapy might have prevented the CSF from filling the scala. In addition, it is also possible that the VP shunt might have altered the CSF pressure, leading to depletion of the perilymph.

Bilateral Sequential Pneumolabyrinth Resulting from Nose Blowing

Pneumolabyrinth describes a condition with entrapped air in the labyrinth and usually occurs in temporal bone fractures that involve the otic capsule. While sporadic cases of bilateral pneumolabyrinth have been reported, cases lacking head trauma are very rare. We report the case of a 43-year-old man who had sudden hearing loss bilaterally after blowing his nose at an interval of 1 year. Although conservative management for the right ear and exploratory tympanotomy with sealing of the possible site of perilymphatic leakage in the left ear were performed, hearing outcome was poor in both ears. To our knowledge, this is the first case of bilateral pneumolabyrinth occurring as a result of nose blowing.

Case report illustrating the importance of systematic emergency management

INTRODUCTION

Temporal bone fracture is a common complication of high-energy cranial trauma. Labyrinth involvement is rare, but there is a risk of perilymphatic rupture that is often underestimated on initial clinical examination due to the predominance of neurological and/or somatic symptoms.

CASE REPORT

A patient presented with overlooked perilymphatic fistula, decompensated by hyperpressure effort due to poorly adapted management.

DISCUSSION

Following a review of the literature on post-traumatic pneumolabyrinth, overall management (from diagnosis to treatment, via prevention advice) was analyzed. A constructive critique of the patient's treatment was thus made.

CONCLUSION

We argue for a systematic management protocol in cranial trauma with temporal bone fracture, comprising ENT examination, millimetric-scale cross-sectional imaging of the fracture site, and standardized counseling to prevent late complications.