Simple Technique Using an Additional Landmark to Reliably Identify the Trunk of Facial Nerve During Parotidectomy: a Cadaveric and Clinical Correlation Study.

Abstract

The incidence of facial palsy in parotid surgeries is up to 50% transient and 17% complete facial palsy. Locating facial nerve trunk during parotid surgery can be tricky despite using the standard landmarks. During a cadaveric dissection, we came across a simple technique to identify the trunk of facial nerve which we have also tried to use it in clinical setting and found it to be useful. Parotidectomy was done in 12 cadaveric hemi-faces. The distance between the mastoid tip and the tympanic segment of facial nerve was measured. The distance of the facial nerve and mastoid tip and tympanomastoid suture and facial nerve was measured. The trunk of facial nerve was found to cross the tympanomastoid sulcus-mastoid tip at around 8-10mm from the mastoid tip in 70% of the cases. We extrapolated this information in 5 cases of parotidectomy in operative setting. We were able to identify facial nerve trunk accurately in 4/5 cases. Imaginary line connecting the mastoid tip and tympanomastoid suture can be used to locate the probable position of the facial nerve trunk reliably during parotidectomy.