Dynamics of loss and recovery of the nerve monitoring signal during thyroidectomy predict early postoperative vocal fold function.
The characteristics of segmental type 1 and global type 2 injuries to the recurrent laryngeal nerve (RLN) and the extent and dynamics of nerve recovery are poorly understood.



This investigation of 785 patients who underwent thyroidectomy under continuous intraoperative nerve monitoring aimed at exploring the dynamics of loss and recovery of the nerve monitoring signal and its relationship to early postoperative vocal fold palsy.



Persistent complete loss of signal and signal recovery <50% identified all (based on 12 and 4 patients with type 1 injuries) or most (based on 9 of 12 and 4 of 6 patients with global type 2 injuries) early unilateral vocal fold palsies. Signal recovery ≥50% (based on 7 patients) always signified normal vocal fold function.



These data, including the observation that global type 2 injuries may entail less severe nerve injury, require validation in independent series before being adopted more widely. © 2015 Wiley Periodicals, Inc. Head Neck 38: E1144-E1151, 2016.
Department of General, Visceral, and Vascular Surgery, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany.
Rick
R
Schneider
Department of General, Visceral, and Vascular Surgery, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany.
Carsten
C
Sekulla
Department of General, Visceral, and Vascular Surgery, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany.
Andreas
A
Machens
Department of General, Visceral, and Vascular Surgery, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany.
Kerstin
K
Lorenz
Department of General, Visceral, and Vascular Surgery, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany.
Phuong Nguyen
PN
Thanh
Department of General, Visceral, and Vascular Surgery, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany.
Henning
H
Dralle
D006801:Humans; D064795:Intraoperative Neurophysiological Monitoring; D012009:Recurrent Laryngeal Nerve / Q000503:physiopathology; D061226:Recurrent Laryngeal Nerve Injuries / Q000175:diagnosis* / Q000517:prevention & control; D012189:Retrospective Studies; D013965:Thyroidectomy / Q000009:adverse effects*; D014826:Vocal Cord Paralysis / Q000175:diagnosis* / Q000517:prevention & control; D014827:Vocal Cords / Q000503:physiopathology
early postoperative vocal fold function; global recurrent laryngeal nerve injury; intraoperative neuromonitoring; loss of signal; segmental recurrent laryngeal nerve injury; vocal fold palsy