Vocal fold paralysis after anterior cervical spine surgery: incidence, mechanism, and prevention of injury.

OBJECTIVE

Vocal fold paralysis is the most common otolaryngological complication after anterior cervical spine surgery (ACSS). However, the frequency and etiology of this injury are not clearly defined. This study was performed to establish the incidence and mechanism of vocal fold paralysis in ACSS and to determine whether controlling for endotracheal tube/laryngeal wall interactions induced by the cervical retraction system could decrease the rate of paralysis.

STUDY DESIGN

Retrospective review and complementary cadaver dissection.

METHODS

Data gathered on 900 consecutive patients undergoing ACSS were reviewed for complications and procedural risk factors. After the first 250 cases an intervention consisting of monitoring of endotracheal tube cuff pressure and release of pressure after retractor placement or repositioning was employed. This allowed the endotracheal tube to re-center within the larynx. In addition, anterior approaches to the cervical spine were performed on fresh, intubated cadavers and studied with videofluoroscopy following retractor placement.

RESULTS

Thirty cases of vocal fold paralysis consistent with recurrent laryngeal nerve injury were identified with three patients having permanent paralysis. With this technique temporary paralysis rates decreased from 6.4% to 1.69% (P = .0002). The cadaver studies confirmed that the retractor displaced the larynx against the shaft of the endotracheal tube with impingement on the vulnerable intralaryngeal segment of the recurrent laryngeal nerve.

CONCLUSION

The study results suggest that the most common cause of vocal fold paralysis after anterior cervical spine surgery is compression of the recurrent laryngeal nerve within the endolarynx. Endotracheal tube cuff pressure monitoring and release after retractor placement may prevent injury to the recurrent laryngeal nerve during anterior cervical spine surgery.