A new landmark for the identification of the facial nerve during parotid surgery: A cadaver study

Abstract

Objective Precise knowledge of facial nerve anatomy is crucial for parotid surgery. Although several surgical landmarks to identify the facial nerve have been described in literature, their position is variable, inconsistent, and difficult to follow in some cases. The purpose of this study was to prove that the facial nerve trunk (FNT) is located midway between the mastoid tip (MT) and osteocartilaginous junction of the external auditory canal (EAC). Methods A prospective study of 7 frozen cadaver specimens, of which 13 facial sides were dissected. The distances between the osteocartilaginous junction and the MT, between the FNT and the MT, and between the FNT and the osteocartilaginous junction were recorded, respectively. Results The distance between the osteocartilaginous junction and the MT ranged from 17 to 21 mm, with a mean of 19.5 mm (SD = ±1.19). The mean distances between the osteocartilaginous junction and the FNT and between the MT and the FNT were 9.2 mm (±1.58) and 10.3 mm (±1.79), respectively. Conclusion The FNT was consistently located close to the midpoint between mastoid tip inferiorly and bony‐cartilaginous junction of the EAC superiorly. Level of Evidence NA

Facial Nerve Morbidity after Superficial Parotidectomy in the Absence of Nerve Conductor: A Cross-Sectional Study from a Tertiary Centre in Pakistan

“…These include the identification of stylomastoid foramen, posterior belly of the digastric muscle, tragal pointer, mastoid process, tympano-mastoid suture and identification of peripheral branches of the facial nerve. Al-Qahtani et al, after cadaveric dissection, have recently confirmed the consistent location of the facial nerve truck at the midpoint between the mastoid tip inferiorly and the osteocartilaginous junction of the external auditory canal superiorly 12,14 . As the evidence does not superior antegrade to retrograde dissection and where anatomical identification is the primary approach, it is also advised to limit the exploration of the facial nerve to the branches in close relation with the adenoma 15,16 .…”

Styloid Process Is the Robust Landmark for Identification of the Facial Nerve during Parotid Surgery

“…Parotid surgery is warranted for benign and malignant neoplasm, chronic inflammatory diseases, sialolithiasis, intra-parotid cysts/sinuses and lymphadenopathy, and many other diseases. The methods of identification of the facial nerve and its importance are aptly described by many eminent surgeons using various anatomical landmarks during parotidectomy [4]. In this article styloid process is considered the very consistent robust anatomical landmark in the triangle technique in conjunction with the tragal cartilage to tragal pointer and the origin of the posterior belly of the digastric muscle at the mastoid tip.…”

Precise extratemporal pattern and intramuscular distribution of the facial nerve

“…20,26 Many researches have been widely investigated the distance of the anatomical landmarks to the facial nerve trunk (Table 1)(Figure 20). 4,67,[70][71][72][73][74][75][76][77] Figure 20 Distance of the temporal branch of the facial nerve correlated to the external auditory. [70][71][72] Table 1 The distance of the facial nerve trunk to the anatomical landmarks.…”

“…[70][71][72] Table 1 The distance of the facial nerve trunk to the anatomical landmarks. Al-Qahtani et al 77 (2020)…”

“…Figure 21 Right side of the face in the cadaveric dissection presents anatomical landmarks and the facial nerve trunk (FNT). TP, tragal pointer; MT, tip of mastoid process (blue arrow); PBDM, posterior belly of the digastric muscle, mastoid process (black dotted line), the osteocartilagenous junction (OCJ) (green line), the tympanomastoid suture (red line) 77 The patterns of the facial nerve were first explained by Davis et al in 1956. Six types (I, II, III, IV, V and VI) of this was identified related to anastomosis of the terminal branches (Figure 22).…”