[Microsurgical anatomy of the recurrent laryngeal nerve: applications on the anterior approach to the cervical spine].
OBJECTIVE
To present an anatomical description of the recurrent laryngeal nerve (RLN) on both sides of the larynx as it relates to the possible lesion mechanisms in anterior cervical spine surgery.


METHODS
Twelve adult cadavers were examined from the microsurgical laboratory at the School of Medicine at UFMG, MG, Brazil. The data collected were analyzed in terms of frequency, average and standard deviation.


RESULTS
The left RLN had a total average length of 9.4 +/- 1.6 cm entering the larynx in 36.3% of the cases at the approximate height of C5, 18.2% at C4, 18.2% at C5-C6, 18.2% at C6 and 9.1% at C4-C5. Recurrence appeared in 45.4% of the cases at the approximate height of T3, 18.2% at T3-T4, 18.2% at T4 and 18.2% at T5. The right RLN had a total average length of 5 +/- 0.3 cm entering the larynx in 44.4% of the cases at the approximate height of C5, 44.4% at C6, and 11.1% at C3-C4. Recurrence appeared in 60% of the cases at the approximate height of T1, 30% at C7 and 10% at T2.


CONCLUSIONS
The right RLN was found to be more vulnerable to operational lesions due to two complimentary yet different reasons, trajectory and length. Owing to the fact that a more oblique and unprotected trajectory is not related directly with the tracheoesphageal groove, there is a strong possibility of direct traumas occurring as with the resulting compression from the employ of surgical retractors or an accidental cut, principally in surgeries involving lower vertebral levels. In the same way, the smallest RNL length favors the stretching of fibers during the per-operative traction.
Arantes
Aluízio
A
Laboratório de Microcirurgia, Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil. aluizio_arantes@uol.com.br
Gusmão
Sebastião
S
Rubinstein
Fabiana
F
Oliveira
Raquel
R
D000328:Adult; D003389:Cranial Nerve Diseases / Q000601:surgery*; D004210:Dissection; D006801:Humans; D008866:Microsurgery; D012009:Recurrent Laryngeal Nerve / Q000033:anatomy & histology* / Q000601:surgery*