Dehiscence of the Third Portion of the Facial Nerve

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Acta Otorrinolaringol Esp. 2013;64(2):165
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IMAGES IN OTORHINOLARYNGOLOGY
Dehiscence of the Third Portion of the Facial Nerve夽
Dehiscencia de la tercera porción del nervio facial
María Luisa Navarrete,a,∗ Juan Ramón Moya,a Sofía Cavallettob
a
Unidad de Otoneurología, Servicio de Otorrinolaringología, Hospital Vall d’Hebron, Universidad Autónoma de Barcelona,
Barcelona, Spain
b
Unidad de Neurorradiología, Servicio de Radiología, Hospital Vall d’Hebron, Universidad Autónoma de Barcelona, Barcelona,
Spain
Dehiscence of the mastoid portion of the facial nerve is
extremely rare. According to different authors in the literature reviewed, anatomical alterations of the third portion
of the facial nerve (dehiscence, route changes and nerve
branching) have an incidence of 7.45%, of which 0.67%
are dehiscences. Regarding a casuistry of 1150 patients
who underwent cochlear implantation, the percentage corresponded to 1.91% alterations of that portion, of which
0.17% were dehiscences. In our experience of work conducted at our department with 164 patients suffering Bell
peripheral facial paralysis studied radiologically, 16.19% presented dehiscence-type alterations in petrosal computed
tomography (CT) scans. Out of these, the second portion
was affected in 100% of cases and in no case was the third
portion of the nerve affected.
Due to their rarity, we present CT images of a patient with
right, severe, peripheral facial palsy (electroneurography of
1%) who presented dehiscence of the third portion of the
facial nerve up to the jugular bulb in the radiographic study
(Figs. 1 and 2).
Figure 1 Axial multiplanar reconstruction (MPR) of 0.2 mm
width, showing an absence of bone wall at the level of the facial
nerve channel in its third section.
夽 Please cite this article as: Navarrete ML, et al. Dehiscencia
de la tercera porción del nervio facial. Acta Otorrinolaringol Esp.
2013;64:165.
∗ Corresponding author.
E-mail address: [email protected] (M.L. Navarrete).
Figure 2 Coronal MPR of 0.2 mm width, showing an absence
of bone wall at the level of the mastoid facial nerve channel.
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