Anatomic Variations From 120 Mental Nerve Dissections: Lessons for Transoral Thyroidectomy
Document Type
Article
Publication Title
Journal of Surgical Research
Abstract
Background:
Transoral endoscopic thyroidectomy vestibular approach (TOETVA) is a promising technique for eliminating a neck incision. A new risk of TOETVA is the potential for injury to the mental nerves during placement of three oral endoscopic ports. A better understanding of the variations in mental nerve anatomy is needed to inform safer TOETVA technique.
Materials and methods:
We performed 120 dissections of mental nerve branches exiting the mental foramen in 60 human cadavers. Anatomic distances and relationships of the foramen to the midline were evaluated. Mental nerve branching patterns were studied and compared with previously reported classification systems to determine surgical safe zones free of nerve branches.
Results:
The mean midline-to-mental foramen distance was 29.2 ± 3.3 mm, with high variability across individuals (18.8-36.8 mm). There were differences in this distance between the left and right foramina (29.8 ± 3.2 versus 28.8 ± 3.3 mm, P = 0.03). All mental nerve branches exiting the mental foramen distributed medially. The branching patterns were classified into eight distinct categories, three of which are previously undescribed. One of these novel patterns, occurring in 9.2% of cases, had a dense and wide clustering of branches traveling toward the midline.
Conclusions:
The location of the mental foramen and mental nerve branching patterns demonstrate high variability. To avoid mental nerve injury in TOETVA, we identify a safe zone for lateral port placement lateral to the plane of the mental foramen. Placement and extension of the middle port incision should proceed with caution, as clustering of mental nerve branches in this area can frequently be present.
DOI
10.1016/j.jss.2020.07.018
Publication Date
12-2020
Keywords
Mental nerve, TOETVA, thyroidectomy, transoral endoscopic thyroidectomy
ISSN
1095-8673
Recommended Citation
King SD, Arellano R, Gordon V, Olinger A, Seib CD, Duh Q, Suh I. Anatomic Variations From 120 Mental Nerve Dissections: Lessons for Transoral Thyroidectomy. Journal of Surgical Research. 2020; 256. doi: 10.1016/j.jss.2020.07.018.
