Abstract
Facial baroparesis is a rare transient facial nerve palsy caused by compression of the tympanic segment of the facial nerve. However, otolaryngologists are lacking sufficient information about the course and treatment of this disease. We report a case of facial baroparesis relieved by endoscopic sinus surgery (ESS). A 41-year-old man presented with a one-year history of recurrent right facial palsy that only developed during altitude changes in an aircraft. Computed tomography (CT) of the temporal bone revealed dehiscence of the tympanic portion of the facial nerve canal. Based on the CT finding and clinical course, the patient was diagnosed with facial baroparesis. He was also diagnosed with chronic rhinosinusitis with nasal polyps (CRSwNP), and thereafter underwent ESS. For 4 years after surgery, he has not experienced facial palsy during airplane altitude changes. To our knowledge, this is the first case report of facial baroparesis relieved by ESS.
Introduction
Facial baroparesis is a transient facial palsy caused by pressure changes in the middle ear [Citation1]. It is a relatively rare condition, with cases reported to date involving scuba diving and altitude changes in airplanes [Citation2]. Facial baroparesis is considered to result from ischemic neuropraxia of the facial nerve, caused by Eustachian tube dysfunction and bony defects in the tympanic segment of the facial nerve canal [Citation3]. Currently, there are several treatments for facial baroparesis, including tympanostomy tube insertion, Eustachian tube dilation, and nasal decongestant spray [Citation2]; however, there are no reports of the disease being treated with endoscopic sinus surgery (ESS). Herein, we report a case of facial baroparesis, improved by ESS for comorbid chronic rhinosinusitis with nasal polyps (CRSwNP).
Case presentation
A 41-year-old man with nasal obstruction and seasonal allergic rhinitis presented to our hospital with right transient facial nerve palsy that only developed during airplane altitude changes. He was taking montelukast and bilastine for allergic rhinitis. He experienced the facial paralysis, once each during altitude ascent and descent in one year. The episodes were preceded by right otalgia and ear fullness, and spontaneously relieved within 15 min after onset. He did not experience other concurrent symptoms including vertigo, dizziness, or contralateral ear symptoms during airplane altitude changes. In addition, the facial nerve palsy occurred when his flight coincided with periods of worsening nasal obstruction due to a viral upper respiratory infection or seasonal allergic rhinitis. On his initial visit, facial nerve palsy was not present. Type B tympanogram of the right side was observed, and the cone of light in the right tympanic membrane was slightly weakened, suggesting Eustachian tube dysfunction and middle ear fluid (Figure ). Computed tomography (CT) of the temporal bone revealed dehiscence of the tympanic segment of the right facial nerve canal (Figure ). Based on the episodes over the past year and the findings regarding the tympanogram and the temporal bone CT, he was diagnosed with facial baroparesis. Nasal endoscopy showed nasal polyps reaching the common meatus (Figure ). Plain CT of the sinus revealed opacification of bilateral maxillary and ethmoid sinuses (Figure ). Based on these findings, the patient was also diagnosed with CRSwNP. To improve nasal obstruction symptoms and Eustachian tube function, we performed ESS for CRSwNP. Four years after surgery, the patient never experienced facial paralysis during the airplane altitude changes.
Figure 1. Image of right tympanic membrane. Cone of light is slightly weakened.
Figure 2. Images of right temporal bone computed tomography. Dehiscence of the tympanic segment of the facial nerve canal is visualized (arrow head). (A) and (B) show axial and coronal view, respectively.
Figure 3. Endoscopic image of the right nasal cavity. Nasal polyps reaching the common nasal meatus are visualized (arrow head).
Figure 4. Images of sinus computed tomography. Soft tissue density lesions were filling maxillary and ethmoid sinuses on both sides. (A,B) show axial and coronal view, respectively.
Discussion
Facial baroparesis is a disease caused by a difference in the pressure of the middle ear and the external environment; and not well recognized by otolaryngologists and general physicians [Citation2]. Facial baroparesis is considered to develop based on two abnormalities: dysfunction of the Eustachian tube and dehiscence of the tympanic segment of the facial nerve canal [Citation4]. There are several basic studies on the pathophysiology of the disease. Roffman et al. [Citation5] reported that the application of 150–200 mmHg pressure for 15 min to the surgically exposed facial nerve of a cat caused transient ischemic neuropraxia of the facial nerve. During aircraft ascent, the increase in the middle ear pressure relative to the external pressure may compress the vasa nervorum of the tympanic segment of the facial nerve, resulting in ischemic neuropraxia of the facial nerve. Additionally, the time of pressure on the facial nerve is quite short in human facial baroparesis cases, thus it is inferred that the disease is reversible. Conversely, during aircraft descent, the pressure on the blood vessels in the middle ear is reduced, so another mechanism may exist. Alperet al. [Citation6] reported that decompression in the middle ear leads to ischemia due to the increased permeability of blood vessels exposed in the middle ear. It is speculated that neuropraxia may occur due to the permeability increase in the vasa nervorum of the facial nerve. Cases of facial baroparesis occurring during aircraft ascent [Citation7–9] and descent [Citation1] have been reported, respectively. Dehiscence of the tympanic segment of the facial nerve canal is a necessary factor in the development of facial baroparesis. Moreano et al. [Citation10] reported that 56% of the healthy population had at least one facial canal dehiscence in a review of 1000 autopsy cases of the temporal bone. Although dehiscence of the facial nerve canal is not so uncommon, it seems very rare to encounter facial baroparesis in clinical practice. According to a systematic review by Alwan et al. [Citation2], only 23 cases of facial baroparesis due to aircraft altitude change have been reported to date. Review articles on otic barotrauma [Citation10] usually do not mention facial baroparesis, suggesting a lack of awareness of this condition among clinicians.
Eustachian tube dysfunction is an important mechanism involved in the pathogenesis of facial baroparesis. In the previously reported cases of facial baroparesis, treatment for Eustachian tube dysfunction, such as tympanostomy tube insertion, Eustachian tube dilation, and nasal decongestant spray have been successfully administered [Citation1,Citation2,Citation11]. CRS is a disease known to be involved in Eustachian tube dysfunction, and there are reports that ESS for CRS has improved Eustachian tube function [Citation12,Citation13]. It is believed that ESS improves the inflammatory state of the nasal cavity to the nasopharynx, mucosal thickening, and ciliary function, which leads to improvement of Eustachian tube function [Citation12]. To our knowledge, there is no case report of facial baroparesis that improved after ESS. Considering the involvement of Eustachian tube dysfunction in the pathogenesis of facial baroparesis, clinicians should be mindful of ESS as a treatment option in cases complicated by CRS.
Facial baroparesis itself is not a disease that significantly worsens quality of life, because it only causes transient symptoms during changes in external pressure. However, low awareness of this disease may lead to unnecessary and costly procedures being performed on patients. For example, it could be misdiagnosed as an air embolism or stroke [Citation7]. Therefore, reports and education about this rare condition are important.
A limitation of this report should be recognized. We cannot rule out the possibility that the facial baroparesis improved spontaneously; albeit previous studies [Citation1,Citation2,Citation8] reported treatment for Eustachian tube dysfunction leads to the cure of facial baroparesis. We cannot objectively prove that ESS improved Eustachian tube function. In the present case, ESS was performed to improve nasal obstruction caused by CRSwNP. Therefore, even if the effect on facial baroparesis is uncertain, we believe it was a reasonable treatment choice.
Conclusion
We reported a case of facial baroparesis on airplane flights that improved after ESS for comorbid CRSwNP. This report adds to the current knowledge base by suggesting that ESS may improve Eustachian tube dysfunction in cases of facial baroparesis complicated by CRS and relieve the facial palsy on airplane flights. Optimal treatment of facial baroparesis is not conclusively established; therefore, education about this rare condition and accumulation of a greater number of cases are necessary.
Informed consent
Written informed consent was obtained from the patients for the publication of any potentially identifiable images or data included in this article.
Disclosure statement
No potential conflict of interest was reported by the author(s).
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References
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