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

Objective: Vocal fold paralysis is the most com mon otolaryngological compl ication after anterior cervical spine surgery (ACSS). However, the frequenc y and etiology of this injury are not clearly defined. This study was perfo rmed to establish the incidence and mechanism of vocal fold paralysis in AC SS and to determine whether controlling for endotracheal tube/laryngeal wal l interactions induced by the cervical retraction system could decrease the rate of paralysis. Study Design: Retrospective review and complementary ca daver dissection. Methods: Data gathered on 900 consecutive patients underg oing ACSS were reviewed for complications and procedural risk factors. Afte r the first 250 cases an intervention consisting of monitoring of endotrach eal tube cuff pressure and release of pressure after retractor placement or repositioning was employed. This allowed the endotracheal tube to re cente r within the larynx. In addition, anterior approaches to the cervical spine were performed on fresh, intubated cadavers and studied with videofluorosc opy following retractor placement. Results: Thirty cases of vocal fold para lysis consistent with recurrent laryngeal nerve injury were identified with three patients having permanent paralysis, With this technique temporary p aralysis rates decreased from 6.4% to 1.69% (P = .0002). The cadaver studie s confirmed that the retractor displaced the larynx against the shaft of th e endotracheal tube with impingement on the vulnerable intralaryngeal segme nt 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 en dolarynx. Endotracheal tube cuff pressure monitoring and release after retr actor placement may prevent injury to the recurrent laryngeal nerve during anterior cervical spine surgery.