Anomalies of the facial nerve: a surgeon’s nightmare
Keywords:Facial nerve, Anomaly, Expertise, Precaution
Background: Most of the anomalies of the facial nerve have been encountered during otological surgery or dissection of the temporal bones. ENT surgeons are taught from a nascent stage to always be wary of an anomalous facial nerve during otological surgery. Today’s surgeon is assisted with high definition imaging and nerve monitoring; yet iatrogenic facial palsy still is encountered even today.
Methods: This study was conducted in a select population of patients who reported with aural symptoms with an aim to see the number of facial nerve anomalies one encounters during aural surgery. The filter applied was no patient with congenital anomaly was considered and patients with squamous COM were also excluded.
Results: Almost 4.5% of the patients subjected to surgery had varying kinds of facial nerve anomaly, the most common being dehiscence of the fallopian canal.
Conclusions: Facial nerve anomalies are not so uncommon as one expects it to be. So it is mandatory that every ENT surgeon should be well versed with facial nerve anatomy and be wary of any structural anatomical abnormality, and irrespective of the experience it pays to be extra cautious when operating on the ear because in the event of damage to the facial nerve the patient has to carry the stigma of a facial deformity for his/her life.
Van Swearingen JM, Cohn JF, Turnbull J, Mrzai T, Johnson P. Psychological distress: linking impairment with disability in facial neuromotor disorders. Otolaryngol Head Neck Surg. 1998;118(6):790-6.
Hohman MH, Bhama PK, Hadlock TA Epidemiology of iatrogenic facial nerve injury: a decade of experience. Laryngoscope. 2014;124(1):260-5.
Baxter A. Dehiscence of the fallopian canal. J Laryngol Otol. 1971;85(6):587–59.
Takahashi H, Sando I. Facial canal dehiscence: histologic study and computer reconstruction. Annals Otol, Rhinol Laryngol. 1992;101(11):925–30.
Gupta S, Mends F, Hagiwara M, Fatterpekar G, Roehm PC. Imaging the facial nerve: A contemporary view. Available at: Researchgate. net/publication/ 237844132. Accessed on 3 May 2018.
Pensak ML, Willging JP, Keith RW. Intraoperative facial nerve monitoring in chronic ear surgery: a resident training experience. Am J Otol. 1994;15(1):108-10.
Hu J, Fleck TR, Xu J, Hsu JV, Xu HX. Contemporary changes with the use of facial nerve monitoring in chronic ear surgery. Otolaryngol Head Neck Surg. 2014;151:473-7.
Gragnaniello C, Kamel M, Al-Mefty O. Utilization of fluorescein for identification and preservation of the facial nerve and semicircular canals for safe mastoidectomy: a proof of concept laboratory cadaveric study. Neurosurgery. 2010;66:204–7.