Non-Recurrent Laryngeal Nerve - A Surgical Challenge

Abstract

Shib Shankar Paul1 , Subrata Kumar Sahu2 , Indranil Chatterjee3

Both the cases discussed here had right sided NRLN, out of which one had 
associated aberrant right subclavian artery. None had iatrogenic nerve palsy. 
Dissection was difficult as during the routine procedure of dissection, the nerve 
was not found in its usual route and was found that the right laryngeal nerve was 
not recurrent and originated directly from the vagus nerve.
The non-recurrent laryngeal nerve (NRLN) is a rare embryologically derived 
variant of the recurrent laryngeal nerve and is found in 0.25 to 0.99% of patients 
who undergo thyroid surgery. On the right side, NRLN is found in 0.3% to 0.8% 
of patients and it is extremely rare on the left (0.004%).[1-2] The right NRLN is 
found to be associated with an aberrant right subclavian artery (86.7%)
In experienced hands, meticulous dissection in the region of the 
tracheoesophageal groove will result in identification of RLN. In any case, if the 
nerve is not seen / found longitudinally along the tracheoesophageal groove, then 
dissecting transversely along the fascial spaces between the carotid sheath and 
the larynx, will allow identification of the presence of NRLN.
Recurrent laryngeal nerve is a branch of the vagus nerve that is associated 
with both motor function and sensation of the larynx. It supplies all the intrinsic 
muscles of the larynx except the cricothyroid muscles. The non-recurrent laryngeal 
nerve (NRLN) is a rare embryologically derived variant of the recurrent laryngeal 
nerve and occurs in 0.25 to 0.99% of patients who undergo thyroid surgery and 
was first reported by Steadman in 1823.[3] on the right side, NRLN is found in 
0.3% to 0.8% of patients and on the left side, it is extremely rare (0.004%).[1-2]
The right NRLN is found to be associated with an aberrant right subclavian artery 
(86.7%).

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