Abstract
Objective: To study variations in recurrent laryngeal
nerve (RLN) bifurcation in extra laryngeal course in
neck, to prevent vocal cord palsy due to its damage.
Methodology: This prospective study was completed
from October 2020 to March 2021 at anatomy
department with the collaboration of general surgery
department of Dow University of Health Sciences and
Dow Hospital, Ojha Campus, Karachi. A total of 240
RLNs in 120 patients, undergoing thyroid surgery
were studied. Cervical course was classified into four
segments based on two anatomical landmarks, nerveartery crossing and laryngeal entry. Four segments
were pre-arterial, arterial, post arterial and prelaryngeal. According to these segments, point of nerve
bifurcation was observed and compared on both sides
of the neck.
Results: Out of 240 RLNs, 55 (40 cases) were
bifurcated. Bilateral bifurcation was found in 15
(12.5%) patients and 30 RLNs. Unilateral bifurcation
was found in 25 (20.8%) cases (25 RLNs) including
right side bifurcation in 11 (9.2%) and left side
bifurcation in 14 (11.7%) cases.
Conclusion: Extra laryngeal bifurcation of RLN is a
common variation. In this study bilateral extra
laryngeal bifurcation of RLNs were found in 33.3%.
Awareness of surgeons of variations in RLNs
bifurcation can prevent injury of the nerve and vocal
cord paralysis.
Keywords: Recurrent laryngeal nerve, nerve
bifurcation, anatomic variation, vocal cord palsy,
thyroid surgery.
