Introduction
Recognition of extralaryngeal branching of the recurrent laryngeal nerve (RLN) is
crucial, because inadvertent operative division may lead to significant postoperative
morbidity. The purpose of this study was to examine the incidence of extralaryngeal
bifurcation of the RLN and to demonstrate the location of the motor fibers within
the branches of the RLN.
Methods
Prospective study on 99 patients over 1 year with operative data collected on the
branching of a total of 137 RLNs. Operative data obtained included the type of operation,
incidence of nerve bifurcation, the distance from the inferior border of the cricothyroid
to the point of bifurcation, and the location of the motor fibers to the intrinsic
muscles of the larynx within the branches of the RLN.
Results
The RLN was seen intra-operatively in all patients. A total of 137 (right 69, left
68) RLNs in 99 patients undergoing thyroidectomy (total 29; hemi 51), parathyroidectomy
(16) and central lymph node dissection (3) were studied. Overall, 46 RLNs (34%) bifurcated
prior to entry into the larynx. These bifurcations occurred on the right in 27 (59%)
and left 19 (41%). Bilateral bifurcation occurred in 12 (27%) of the 44 patients who
underwent bilateral dissections. The median branching distance from the cricothyroid
membrane on the right was 8.3 ± 2.5 mm, and on the left was 7.5 ± 1.8 mm. In all bifurcated
RLNs, the motor fibers to the vocal cords were located exclusively in the anterior
branches.
Conclusion
Extralaryngeal bifurcation was found in 34% of the RLNs in this case series. The motor
fibers of RLN are located in the anterior branch while the posterior branch is only
sensory in function. Great caution is, therefore, required after the presumed identification
of the RLN to ensure there is no unidentified anterior branch. Identification of the
anterior branch may lead to decreased risk of postoperative nerve injury.
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Article info
Publication history
Published online: April 19, 2011
Accepted:
February 10,
2011
Footnotes
Supported by Tulane University and Tulane University Hospital.
Identification
Copyright
© 2011 Mosby, Inc. Published by Elsevier Inc. All rights reserved.
