|Year : 2012 | Volume
| Issue : 1 | Page : 5-9
Unilateral pediatric vocal cord paralysis: Evolving trends
Nancy Grover, Abir Bhattacharyya
Department of Otolaryngology Head and Neck Surgery, Whipps Cross Hospital, London, E11 1NR, United Kingdom
|Date of Web Publication||9-Apr-2012|
Department of Otolaryngology Head and Neck Surgery, Whipps Cross Hospital, London, E11 1NR
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Unilateral vocal cord paralysis (UVCP) in children is a rare and challenging disorder for the pediatric otolaryngologist. The overall etiology differs from that in adults, iatrogenic causes are the commonest, followed by traumatic - birth or intubation trauma and neurologic causes. Prolonged spontaneous recovery occurs in up to 50% of cases. Management strategies used for adults have evolved and been utilized in children, with increasing reports of surgical intervention over the last decade. However, number of children treated remains small with no long-term follow-up. We used the terms "vocal cord palsy," "vocal cord paresis," "vocal fold immobility" each limited by "paediatric," "children," to search Medline, Embase, PubMed, Cochrane, and CINHAL. Reference lists were crosschecked to include relevant studies. Only English language literature was searched. Studies specifically relating to unilateral vocal cord or containing relevant data were identified and analyzed. We present our review of literature on pediatric UVCP with emphasis on various interventions for management, especially the growing experience with laryngeal re-innervation.
Keywords: Laryngoplasty, pediatric, palsy, re-innervation, thyroplasty, vocal cord
|How to cite this article:|
Grover N, Bhattacharyya A. Unilateral pediatric vocal cord paralysis: Evolving trends. J Laryngol Voice 2012;2:5-9
| Introduction|| |
Unilateral vocal cord palsy (UVCP) is defined as immobility of the vocal cord owing to disruption of the motor nerve supply to the larynx.  Etiology and consideration for management of the pediatric population differ from adults. Over the past few decades, advances have been made in diagnosis and management, with improvement in outcome measures following intervention. Greater understanding of surgical anatomy and basic science research into growth and genetics of pediatric larynx have contributed in improving outcomes. Recent development of pediatric voice-related quality of life (VRQOL) and a pediatric version of voice handicap index (VHI) will provide a greater insight into these issues in children and implications thereof any treatment. ,
We present our review of literature on pediatric UVCP with emphasis on various interventions for management, especially the growing experience with laryngeal re-innervation.
We used the terms "vocal cord palsy," "vocal cord paresis," "vocal fold immobility" each limited by "paediatric," "children," to search Medline, Embase, PubMed, Cochrane, and CINHAL. Reference lists were crosschecked to include relevant studies. Only English language literature was searched. Studies specifically relating to unilateral vocal cord or containing relevant data were identified and analyzed.
| Incidence and Etiology|| |
The true incidence of UVCP in general pediatric population is unknown. Previous studies of patients diagnosed during laryngoscopy for airway evaluation have reported an incidence varying between 8% and 25%.  There is also a sporadic incidence of vocal cord palsy throughout childhood and is related to progression of treatment of other congenital abnormalities. 
The overall etiology differs from that in adults. Iatrogenic causes are the commonest, followed by traumatic - birth or intubation trauma and neurologic causes. In up to 20%, no cause is identified-idiopathic, this figure being higher in older studies. Rare causes are neoplastic disease, inflammatory causes, prolonged esophageal foreign bodies, and vincristine chemotherapy. Though cardiovascular anomalies have been associated with bilateral vocal cord palsy, it is not a demonstrable cause in unilateral cases. ,,,
An evolving iatrogenic cause is the use of vagal nerve stimulators for treatment of epilepsy when injury might result from manipulation of the nerve. 
Most iatrogenic cases are secondary to cardiothoracic surgery, with the left recurrent laryngeal nerve being most commonly affected. Zbar and Smith have quoted an 8.8% rate of left vocal cord palsy subsequent to patent ductus arteriosus surgery.  Though an isolated genetic cause for bilateral cord palsy has been studied with linkage to a specific HLA and chromosome, to date none has been detected for UVCP. 
| Presentation|| |
Commonest presenting symptoms are stridor-in 70%, dysphonia-in 50%, and feeding difficulties in approximately 25% of patients. ,, Unilateral immobile cord in a small neonatal airway can cause sufficient airway obstruction and result in stridor. The paramedian cord position causes aspiration and voice disorder. 
| Management|| |
Initial evaluation should include a thorough history including birth and family history as this is associated with other systemic conditions. Impact on the respiratory system, feeding, weight gain, and exercise tolerance should be assessed. 
With the recent development and validation of pediatric VHI and VRQOL questionnaire, impact of dysphonia on various domains should be recorded. Patel et al. reported vocal cord injection in two children for voice concerns. One child was treated after a four-year observation period to avoid any negative impact of dysphonia in school environment as perceived by her parents and the medical team. Another patient was treated for hoarseness following acute injury.  Pre- and post-treatment scores with these questionnaires will provide a basis for treatment and measure any subsequent benefits, to allow for comparison in future studies.
Physical examination may reveal stridor, weak cry/cough, and dysphonia.
Formal diagnosis is based upon clinical documentation. Two decades ago, this was solely by means of direct laryngoscopic examination under general anesthesia. , Flexible laryngoscopy is a convenient and safe diagnostic technique allowing bedside examination.  Dynamic assessment during lightening plane of general anesthesia and the ability to palpate the cricoarytenoid joint are exclusively possible only on direct laryngoscopy. Daya et al. have reported association of other airway abnormalities viz. subglottic stenosis, tracheomalacia, and intubation granulomas with unilateral cord palsy,  hence making an argument for thorough assessment under anesthesia, especially for those undergoing a surgical procedure.
Laryngeal ultrasound is a useful adjunctive investigation. , It has a diagnostic accuracy of 89.5% in children older than twelve months. It is less reliable in younger children owing to small size of the neck and consequently a small window of access for the ultrasound probe.
Laryngeal electromyography in children has been explored. Initial reports were not very encouraging, with a high possibility of false-negative recordings. The recordings should hence always be interpreted in context with clinical findings. A more recent report with the use of bipolar needle electrodes has demonstrated usefulness in differentiating vocal cord palsy from fixity in cases of subtle scarring, hence influencing treatment.  They have stressed upon the need for accurate electrode placement in the muscles. Synkinesis in the muscles indicated low probability of recovery leading to early surgical intervention. It is also helpful in cases with combined pathologies. It remains operator dependent-upon the otolaryngologic surgeon for electrode placement and the person interpreting the results. The practical limitations in a pediatric larynx include risks of laryngeal edema or bleeding from electrode placement.
| Treatment|| |
Spontaneous recovery is known to occur at variable times after onset-up to 5 years in iatrogenic cases and 11 years in idiopathic cases. Prognosis is best for neurologic cases followed by idiopathic and iatrogenic. Neurologic or idiopathic cases recover in approximately 75%; UVCP secondary to iatrogenic trauma has long-term recovery rate of approximately 50%, prematurity being associated with worse prognosis. Time to recovery is variable; early reports document most recovery within the first three months from onset; patients developing nerve injury subsequent to cardiac surgery recover at a median of 6.6 months,  those with neurologic cause within 2 years and idiopathic cases over 6 months to 11 years. Recommended observation time before surgery is eight to twelve months. ,,,
Goals of therapy in children with laryngeal palsy should focus around: establishing and maintaining safe and stable airway, obtaining or preserving intelligible speech, swallowing without aspiration, and feeding and growth.  Impact of dysphonia upon social interaction in education or work place can be severe. 
If spontaneous recovery does not occur or compensation is inadequate, speech therapy may be considered. However, it has its own limitations. It has shown good results in older children; utility in younger age group is limited by their ability to participate. Schindler et al. have reported good results in children older than 12 years-subjectively and on objective evaluation.  King and Blumin comment that the ability of the child to interact and participate with the speech pathologist were more important than the absolute age. 
Surgical experience is limited though there has been an emerging trend in the last decade. There has been a shift in thinking from conservative treatment to active surgical intervention in well-selected cases. This is partly due to a greater understanding of the developmental anatomy of the pediatric larynx and partly due to growing experience with surgical techniques in children.
In the past, there has been a concept of growth centers within the cartilage and the potential effects of surgical manipulation upon growth. These have been offset by studies in animal models and human cadavers which have failed to reveal any areas of high cellular proliferation indicative of focal growth centers or any adverse effects of surgery on cartilage growth patterns. ,
The three major techniques utilized are injection laryngoplasty, thyroplasty, and laryngeal re-innervation.
This technique has the advantage of providing immediate improvement in voice and cough.  Most available materials are temporary in nature which might be an advantage in the pediatric population owing to prolonged spontaneous recovery on some patients. Unlike adults, this procedure is performed under general anesthetic because of lack of compliance with an awake patient; hence, the results cannot be judged on table and the quantity of injection and the degree of glottic closure must be estimated by the surgeon.  Patel et al. have however reported successful injection under local anesthesia in office setting for an 18-year-old patient. 
Collagen products have been used most commonly, followed by teflon, fat, and calcium hydroxylapatite [Table 1].
Most procedures have been performed after an adequate observation period; however, two children have successfully undergone injection in an acute setting with resolution of aspiration and return to oral feeding in one. 
This procedure has been successful in all children with aspiration. , Results for voice outcomes have been good with follow-up period ranging from one to six months. Benefits from collagen last for 4 to 6 months and with autologous fat between 1 to 6 months. Available follow-up with calcium hydroxylapatite is only 4 months with good results as shown by improved scores on pediatric VRQOL questionnaire. 
This procedure has evolved for use in the pediatric population over the last ten years and has been shown to be effective and safe [Table 2]. Additionally, the implant may be removed or resized as the larynx grows. Concerns however focus around the small size of the pediatric larynx and the effects that further growth may have on the medialization procedure, considering that revision surgery may be necessary and difficult. Link et al. modified the procedure for children accounting for the anatomically lower position of vocal cord; Gardner et al. suggested a technique for precise visualization of the endolarynx during the procedure to facilitate adequate medialization in an anesthetized child, since clinical assessment of adequacy of medialization on table as assessed in adults is not possible in small children who do not tolerate the procedure under local anesthetic. Sipp et al. performed the procedure in three children combining these two techniques and obtained 100% success. ,, Till the time of writing this article, sixteen thyroplasties have been described in literature for pediatric UVCP, with an evolving trend emerging in the last five years.
To facilitate an understanding of interaction of mechanics of the growing larynx with the implant, long-term results from previously reported cases will be desirable.
This procedure which was first described a hundred years ago has been used as an effective treatment for UVCP. Its experience in the pediatric age group is limited and case series have been published only in the last five years.
The advantages of this technique are maintenance of vocal improvement irrespective of growth of the laryngeal framework or ongoing muscle atrophy and no risk of local inflammatory reaction. In a recent report of this procedure in four pediatric patients, good voice outcomes have been reported as assessed objectively and by perceptual analysis.  VHI has been used postoperatively for all and preoperatively only for one child.
More recently, a modification of this technique has been described in two younger children aged three to six years using the anterior limb of ansa as donor to match the calibre of recurrent laryngeal nerve. Good results were obtained postoperatively at 7 months in one patient as assessed by videostroboscopy and acoustic analysis. No long-term follow-up is available for the other child. They have also reported personal experience with innervation in four other children previously. 
| Conclusion|| |
UVCP is a rare though well-described condition in the pediatric population. Most are diagnosed early with flexible laryngoscopy. More thorough assessment with direct laryngoscopy may be required to rule out the presence of other associated airway abnormalities and in the preoperative setting. The use of ultrasound in diagnosis has been described. Long-term follow-up of previously treated patients with objective assessment will provide further evidence about surgery in this age group.
| Summary|| |
- Newer techniques of electromyography are being explored and may help in confirming diagnosis in difficult cases and assist in management.
- Treatment is required in approximately 25% of diagnosed cases.
- Surgical techniques have been popularized in the last decade with a paradigm shift from conservative measures to active intervention.
- Pediatric VHI and VRQOL scores will provide evidence for impact of surgical interventions on quality of life and need for treatment thereof.
| References|| |
|1.||Daya H, Hosni A, Bejar-Solar I, Evans JN, Bailey CM. Paediatric Vocal Fold Paralysis: A long-term retrospective study. Arch Otolaryngol Head Neck Surg 2000;126:21-5. |
|2.||Boseley ME, Cunningham MJ, Volk MS, Hartnick CJ. Validation of paediatric voice - related quality of life survey. Arch Otolaryngol Head Neck Surg 2006;132:717-20. |
|3.||Zur KB, Cotton S, Kelchner L, Baker S, Weinrich B, Lee L. Paediatric voice handicap index (pVHI): A new tool for evaluating paediatric dysphonia. Int J Paediatr Otorhinolaryngol 2007;71:77-82. |
|4.||Parikh SR. Paediatric unilateral vocal fold immobility. Otolaryngol Clin North Am 2004;37:203-15. |
|5.||Emery PJ, Fearon B. Vocal Cord palsy in paediatric practice: A review of 71 cases. Int J Pediatr Otorhinolaryngol 1984;8:147-54. |
|6.||King EF, Blumin JH. Vocal cord paralysis in children. Curr Opin Otolaryngol Head Neck Surg 2009;17:483-7. |
|7.||Sipp JA, Kerschner JE, Braune N, Hartnick CJ. Vocal fold medialisation in children Injection laryngoplasty, thyroplasty or nerve innervation? Arch Otolaryngol Head Neck Surg 2007;133:767-71. |
|8.||de Gaudemar I, Roudaire M, Francois M, Narcy P. Outcome of laryngeal paralysis in neonates: A long term retrospective study of 113 cases. Int J Pediatr Otorhinolaryngol 1996;34:101-10. |
|9.||Uthman BM, Wilder BJ, Penry JK, Dean C, Ramsay RE, Reid SA, et al. Treatment of epilepsy by stimulation of vagus nerve. Neurology 1993;43:1338-45. |
|10.||Zbar RI, Smith RJ. Vocal fold paralysis in infants twelve months of age and younger. Otolaryngol Head Neck Sug 1996;114:18-21. |
|11.||Rogers JH. Functional inspiratory stridor in children. J Laryngol Otol 1980;94:669-70. |
|12.||Patel NJ, Kerschner JE, Merati AL. The use of injectable collagen in the management of paediatric vocal unilateral fold paralysis. Int J Pediatr Otorhinolaryngol 2003;67:1355-60. |
|13.||Rosin DF, Handler SD, Potsic WP, Wetmore RF, Tom LW. Vocal cord paralysis in children. Laryngoscope 1990;100:1174-9. |
|14.||Berkowitz RG. Neonatal upper airway assessment by awake flexible laryngoscopy. Ann Otol Rhinol Laryngol 1998;107:75-80. |
|15.||Vats A, Worley GA, De Bruyn R, Porter H, Albert DM, Bailey CM. Laryngeal ultrasound to assess vocal fold paralysis in children. J Laryngol Otol 2004;118:429-31. |
|16.||Jacobs IN, Finkel RS. Laryngeal electromyography in the management of vocal cord mobility problems in children. Laryngoscope 2002;112:1243-8. |
|17.||Truong MT, Messner AH, Kerschner JE, Scholes M, Wong-Dominguez J, Milczuk HA, et al. Paediatric vocal fold paralysis after cardiac surgery: Rate of recovery and sequelae. Otolaryngol Head Neck Surg 2007;137:780-4. |
|18.||de Jong AL, Kuppersmith RB, Sulek M, Friedman EM. Vocal cord paralysis in infants and children. Otolaryngol Clin North Am 2000;33:131-49. |
|19.||Narcy P, Contencin P, Viala P. Surgical treatment for laryngeal paralysis in infants and children. Ann Otol Rhinol Laryngol 1990;99:124-8. |
|20.||Smith M, Roy N, Stoddard K. Ansa-RLN reinnervation for unilateral vocal fold paralysis in adolescents and young adults. Int J Pediatr Otorhinolaryngol 2008;72:1311-6. |
|21.||Schindler A, Bottero A, Capaccio P, Ginocchio D, Adorni F, Ottaviani F. Vocal impairment after voice therapy in unilateral vocal fold paralysis. J Voice 2008;22:113-8. |
|22.||Verwoerd-Verhoef HL, Adriaansen FC, Laeijendecker RJ, van Osch GJ, Verwoerd CD. Growth dynamics of the cricoid cartilage and subglottic injury. An autoradiographic and histometric study in the rabbit. Eur Arch Otorhinolaryngol 1997;254 Suppl 1:S101-4. |
|23.||Kim JC, Mankarious LA. Novel cell proliferation marker for identification of a growth centre in the developing human cricoid. Arch Otolaryngol Head Neck Surg 2000;126:197-202. |
|24.||Tucker HM. Vocal cord paralysis in small children: Principles in management. Ann Otol Rhinol Laryngol 1986;95:618-21. |
|25.||Levine BA, Jacobs IN, Wetmore RF, Handler SD. Vocal cord injection in children with unilateral vocal cord paralysis. Arch Otolaryngol Head Neck Surg 1995;121:116-9. |
|26.||Shah RK, Harvey-Woodnorth G, Glynn A, Nuss RC. Perceptual voice characteristics in pediatric unilateral vocal fold paralysis. Otolaryngol Head Neck Surg 2006;134:618-21. |
|27.||Link TD, Rutter MJ, Liu JH, Willging JP, Myer CM, Cotton RT. Paediatric type I thyroplasty: An evolving procedure. Ann Otol Rhinol Laryngol 1999;108:1105-10. |
|28.||Gardner GM, Altman JS, Balakrishnan G. Paediatric vocal fold medialisation with silastic implant: Intraopeartive airway management. Int J Paediatr Otorhinolaryngol 2000;52:37-44. |
|29.||Marcum KK, Wright SC Jr., Kemp ES, Kitse DJ. A novel modification of the ansa to recurrent laryngeal nerve reinnervation procedure for young children. Int J Pediatr Otorhinolaryngol 2010;74:1335-7. |
[Table 1], [Table 2]