Critical to successful parotid surgery is complete tumor removal and safe identification and preservation of the facial nerve. There are a number of accepted anatomic landmarks used to locate the facial nerve, including the use of the tragal pointer, the tympanomastoid suture line; the attachment of the posterior belly of the digastric muscle to the mastoid tip; and the styloid process. Despite these anatomic markers, it can be a challenging and time-consuming process.
The parotid fascia, particularly the parotid–mastoid segment overlying the facial nerve trunk, can be utilized as an additional landmark of depth to help identify the facial nerve trunk during a parotidectomy in conjunction with other commonly used standard anatomic landmarks, suggests a study recently published in the Ear, Nose and Throat Journal.
Steven B. Micucci and colleagues from the Department of Head and Neck Surgery—Otolaryngology, Kaiser Permanente Medical Center, Oakland, CA, USA aimed to describe the parotid fascia as a landmark that can help identify the immediately underlying facial nerve trunk.
Dissection of the parotid fascia and identification of the facial nerve trunk were carried out on 8 fresh cadaveric parotid glands. The attachments and arrangement of the parotid gland and its fascia were evaluated and histologically assessed, with special attention to the fascia overlying the facial nerve trunk.
It was found out that the parotid fascia envelops the posterior aspect of the parotid gland in an open-book fashion. Also, posteriorly, it connects to the anterior and medial aspect of the mastoid tip. Posterosuperiorly, it attaches to the inferior aspect of the tragal pointer. Directly medial to the fascia lies the facial nerve trunk.
Hence, the study concluded that "the parotid fascia, particularly the parotid–mastoid segment overlying the facial nerve trunk, can be utilized as an additional landmark of depth to help identify the facial nerve trunk during a parotidectomy in conjunction with other commonly used standard anatomic landmarks. The parotid fascia sling spans from the mastoid and tragal pointer to the parotid gland and can be easily palpated intraoperatively. Once the fascia is removed, the facial nerve trunk is identified."
https://doi.org/10.1177/0145561319877998