Vocal fold immobility in neonates is the second most common cause of congenital stridor; it can be congenital or acquired, unilateral or bilateral. Premature and extremely low-birth weight neonates have a higher risk of left vocal cord paralysis after PDA ligation (up to 40 %), and in these children the associated morbidity is significantly higher with increased risks for bronchopulmonary dysplasia, reactive airway disease, and need for gastrostomy tube placement [2]. Neonates undergoing a PDA ligation may not present with respiratory symptoms despite the presence of a vocal fold paralysis, and up to 14 % of neonates may have this diagnosis missed without a scheduled post-extubation fiberoptic laryngoscopy [17]. Prospective efforts to assess vocal fold mobility after this procedure are being studied in high-risk, extremely low-birth weight/premature neonates. For all other cardiac surgery in neonates via a median sternotomy, the reported incidence for vocal fold paresis is between 1.7 and 67 %, depending on the type of surgery and the weight of the patient at the time of surgery [5]. On average, one in five neonates undergoing cardiac surgery may encounter vocal fold mobility issues postoperatively. Neonatal cardiac surgery that involves manipulation of the aortic arch may result in a higher incidence of immobility and longer hospitalizations.

Vocal fold mobility disorders may have a greater negative impact on the neonate compared to older children or adults. While older patients may be asymptomatic due to compensation from the contralateral vocal fold, or present with dysphonia and a breathy voice, neonates with unilateral or bilateral vocal fold immobility often present with a weak cry, stridor, respiratory distress, and/or feeding difficulties. Neonates with bilateral vocal fold immobility present with more significant respiratory difficulties and may require endotracheal intubation or eventual tracheotomy placement in about 50 % of cases.

Diagnostic consultation is often requested in neonates who present with dysphonia, stridor, and/or respiratory distress. A complete and thorough history and physical examination can often elucidate the etiology. In neonates with complex coexisting and comorbid medical and neurologic pathology, input from neonatal intensivists and pediatric neurologists may aid in the diagnostic considerations and workup, providing valuable information relating to the patient’s overall prognosis.

Bedside fiberoptic laryngoscopy has become more readily available and is the primary diagnostic tool to assess vocal fold mobility. This nonsedated, awake endoscopic examination of the neonatal larynx will give the examiner the best opportunity to evaluate vocal fold mobility and dynamics. This evaluation may be more technically challenging than in the older patients as these infants have poorer pulmonary reserve and may have complicating, comorbid conditions. Inability to tolerate secretions, lack of patient cooperation, crowding of the nasopharyngeal, oropharyngeal, and supraglottic tissues, and enteric feeding tubes may interfere with introducing the equipment and visualization of the neonatal larynx. Recent extubation or significant laryngopharyngeal reflux can cause edema and erythema, which makes the examination even more challenging. Laryngomalacia, or floppiness of the supraglottic structures, may prohibit adequate visualization of the true vocal folds. Caution should be advised when performing bedside fiberoptic laryngoscopy, especially in the cardiac population, and advanced resuscitation equipment should be readily available when indicated in the unstable patient.

Given these limitations, an assessment of neonates vocal fold mobility can often be difficult, and careful attention should be placed on examining for adduction and abduction of the arytenoid cartilages which often serve as surrogate markers for vocal fold mobility. If there is a history of cardiothoracic surgery and symptoms of a hoarse cry and/or stridor, vocal cord immobility is often discovered. It is also important to rule out a subglottic pathology, as these patients have a history of intubation, which may lead to similar symptoms. Additionally, an initial assessment of pooling of secretions or the neonate’s ability to handle secretions is important to help determine the patient’s risk for aspiration and potential for oral feeding. Assessment for obvious masses or lesions in the supraglottic larynx should be undertaken. A detailed endoscopic view of the neonatal vocal folds, however, with current fiberoptic technology is limited. Large cysts or nodules should be readily visualized, but subtle nodules or submucosal lesions/scars will not be obvious in this age group. Accurate assessment of the subglottis is also not feasible with the bedside flexible laryngoscope.

Congenital infectious causes for vocal fold paralysis include varicella, for which the diagnosis may be confirmed by retinal imaging by the ophthalmologists [13].

The modified barium swallow (MBS) may be needed to be performed in order to assess the safety of oral feeding and the appropriateness of a particular diet under the guidance and supervision of a speech-language pathologist (SLP) and radiologist. The primary drawback to pursuing this study is the exposure of the neonate to ionizing radiation. The study, however, does provide some additional clinical information that may be useful in management and decision-making, as the managing team is also provided diagnostic radiographic images that may help to further delineate airway pathology and help protect the child from pulmonary soiling in cases of silent aspiration.

Cross-sectional imaging may be useful to help elucidate the etiology of vocal fold immobility. The choice is often between magnetic resonance imaging (MRI) and computed tomography (CT). The use of CT is often reserved for cases in which MRI cannot be performed or if there is a specific clinical indication. There is a growing body of literature cautioning the use of CT because of the potential effects of ionizing radiation, especially in young children [1]. MRI provides excellent, high resolution and high fidelity images evaluating for causes of vocal fold mobility disorders in neonates—Arnold Chiari malformation, central nervous system (CNS) abnormalities or malformations, intracranial hemorrhage, and neck or chest soft tissue lesions or vascular malformations. CT is often helpful in older patients to help detect arytenoid dislocation but is limited in neonates because of the lack of calcification of the maturing, laryngeal framework, which may make the pathology difficult to identify. MRI, when available, is probably the best choice for cross-sectional imaging in evaluating neonatal vocal fold paralysis. Small intracranial hemorrhages may be missed on CT. Evaluation and diagnosis of Chiari malformation almost always includes imaging with MRI. Detection of a Chiari malformation significantly impacts the clinical management of the child and necessitates neurosurgical consultation.

The treatment of vocal fold immobility in neonates is primarily guided by the clinical severity of the affected patient. Often this is related to whether the vocal fold immobility is unilateral or bilateral. Unilateral vocal fold immobility in neonates is often managed conservatively, rarely causing significant enough respiratory symptoms to warrant tracheostomy placement. In these cases, medical management for feeding and reflux is often all that is required until further assessments can be made when the patient is older, and their needs can be better evaluated.

The most important aspects of the triage of unilateral vocal fold immobility are the respiratory status and the aspiration risk. Often, affected neonates demonstrate a hoarse cry but rarely any significant respiratory distress. Speech-language pathology consultation should be requested and assessment of the safety for oral intake made. Potential recovery may occur, and therefore, it is prudent to try to delay any permanent intervention for at least 12 months and often longer. If swallowing issues fail to be controlled, or handling of saliva and feeds is not remedied, then a sooner intervention may be needed to protect the lungs.

In rare cases of neonatal arytenoid dislocation there will be a history of stridor after extubation. Laryngoscopy will reveal unilateral immobility of the vocal fold, mimicking paralysis with an anterior and medial displacement of the ipsilateral arytenoid. Neonatal arytenoid dislocation may cause edema and mass effect, making intubation more challenging. In the neonate, management of the airway in such cases must be judicious and is rarely needed. The surgical approach would most likely involve a closed reduction with splinting of the cricoarytenoid joint with an endotracheal tube.

Bilateral vocal fold immobility usually presents with significantly more pronounced respiratory compromise necessitating early intervention. The primary management hinges upon the degree of respiratory symptoms, with 50 % of patients requiring tracheostomy placement. The goal is often to provide a safe temporary airway to bypass the glottic obstruction, and provide time for diagnostic evaluations, treatment options to be attempted, or to await spontaneous recovery.

When a neurologic etiology for bilateral vocal fold paralysis is established, such as in the case of a Chiari malformation, intraventricular hemorrhage, and/or neuraxial malformation, neurology and neurosurgical consultations are recommended. If the lesion is surgically correctable, repair of a central nervous system anomaly has the potential to reverse the paralysis.

Other surgical options include endoscopic or open airway procedures. These types of procedures are more established in infants and children with limited reports of outcomes in neonates. Partial cordotomy has been described to be safe and successful in avoiding tracheostomy placement or aiding in decannulation in a limited number of infants. The technique has not been reported to be associated with a significant risk for functional respiratory or feeding complications but may contribute to more dysphonia as the child grows, and often does not lead to a long-term benefit. This is anecdotal and not currently supported by substantial literature.

Laryngotracheal augmentation with placement of a posterior cricoid costal cartilage graft has been utilized for decannulating children with a tracheostomy in place or in management of airway compromise secondary to bilateral fold paralysis in older patients who have managed to avoid a tracheostomy tube placement at a younger age. This procedure is not well established in neonates as an alternative to placement of a tracheostomy placement in the acute situation.

A recent report of several patients who have undergone an endoscopic anterior–posterior cricoid split with balloon dilation and stenting with an indwelling endotracheal tube shows some promise in neonates who are symptomatic from bilateral vocal fold immobility [15]. Long-term results (>2 years) are not well known, but those patients were able to avoid placement of a tracheostomy tube in the critical period when one would be considered.

The neonate who presents with stridor, hoarseness, and/or feeding difficulties and is found to have a vocal fold mobility issue should undergo a clinical assessment for feeding. Performing a functional endoscopic evaluation of swallowing (FEES) in the infant is feasible, but may provide limited information in this age group. Clinical assessment by a speech-language pathologist is often more appropriate. Safety and prevention of aspiration are of the utmost importance. Often, when there is vocal fold immobility, the ability of the neonatal larynx to compensate and provide protection from aspiration is impaired, especially when compared to adults. The degree to which neonates are affected by vocal fold immobility can vary, but in very low-birth weight patients who develop left vocal cord paralysis after PDA ligation have been shown to have significant feeding difficulties and high rates of gastrostomy tube placement.