How to Reduce Recurrent Laryngeal Nerve Palsy in Anterior Cervical Spine Surgery: A Prospective Observational Study

BACKGROUND: Recurrent laryngeal nerve palsy (RLNP) occurs as a complication during anterior cervical spine surgery. In 2005 the authors demonstrated the high incidence of asymptomatic RLNP in a right-sided approach. OBJECTIVE: This follow-up prospective observational study was designed to test 2 options said to reduce the rate of RLNP: reduced endotracheal cuff pressure and sinistral approach. METHODS: Two hundred forty-two patients in whom anterior cervical spine surgery was performed were examined postoperatively with indirect laryngoscopy to evaluate the status of the vocal cords. All patients had a left-sided approach but 1 group (A, 149 patients) was operated on with an additional reduction of endotracheal cuff pressure to below 20 mm Hg. In 93 patients we could not reduce the cuff pressure. This group served as a control group (B). Both groups were compared with a historic control group with a right-sided approach and no cuff pressure reduction. In cases of vocal cord malfunction a follow-up examination was done 3 months later. RESULTS: Group A (low cuff pressure) had a total rate of persisting symptomatic and asymptomatic RLNP of 1.3% and group B had a rate of 6.5% (normal cuff pressure). Compared with the historic study (N = 120) with a right-sided approach and a total rate of persisting RLNP of 13.3% in the left-sided approach, a marked reduction to 6.5% and 1.3% with an additional reduction of cuff pressure was seen. CONCLUSION: The left-sided approach in anterior cervical spine surgery reduces the incidence of postoperative and permanent RLNP significantly. Endotracheal cuff pressure reduction used additionally decreases the rate of RLNP even more. These results indicate that anterior cervical spine surgery should be performed with a left-sided approach and, if possible, with an additional reduction of the endotracheal cuff pressure while the retractors are inserted.