Adult vs. pediatric larynx, laryngeal nerve palsies and management

Adult vs. pediatric larynx, laryngeal nerve palsies and management

1. Adult vs. Pediatric Larynx, Laryngeal nerve palsies and management Presenter- Dr. Suresh Pradhan Moderator- Prof. UC Sharma

2. The Pediatric Airway structures are more smaller and anterior relatively larger tongue more rostral larynx angled vocal cords differently shaped epiglottis; floppier funnel shaped larynx- narrowest part of pediatric airway is cricoid cartilage larger occiput

3. Anatomy : Larynx laryngeal apparatus develops from brachial clefts and descends caudally higher position infant’s larynx is higher in neck (C 2-3 ) compared to adult’s (C 4-5 ) anterior position

4. Adult Larynx C 4-5 Infant Larynx C 2-3

5. positioned high at C 2-3 at rest and reaches C 1-2 during swallowing laryngeal cartilages are soft and collapse easily epiglottis is omega-shaped arytenoids are large thyroid cartilage is flat overlaps Cricoid is overlapped by hyoid bone

6. infant’s larynx is small and conical diameter of cricoid is smaller hence the narrowest part submucosal tissues are loose and easily go edematous with trauma or inflammation--obstruction

7. Relatively Larger Tongue obstructs airway obligate nasal breathers difficult to visualize larynx straight laryngoscope blade completely elevates the epiglottis, preferred for pediatric laryngoscopy

8. Angled Vocal Cords infant’s vocal cords have more angled attachment to trachea, whereas adult vocal cords are more perpendicular difficulty in nasal intubations where blindly placed ETT may easily lodge in anterior commissure rather than in trachea

9. Differently Shaped Epiglottis adult epiglottis broader, axis parallel to trachea infant epiglottis omega ( Ω ) shaped and angled away from axis of trachea more difficult to lift an infant’s epiglottis with laryngoscope blade

10. Funnel Shaped Larynx narrowest part of infant’s larynx is the undeveloped cricoid cartilage, whereas in the adult it is the glottis opening (vocal cord) tight fitting ETT may cause edema and trouble upon extubation uncuffed ETT preferred for patients < 8 years old fully developed cricoid cartilage occurs at 10-12 years of age

11. narrowest point is cricoid cartilage in the child

12. Laryngeal Nerve Palsies and Management

13. The Vagus vagus nerve has three nuclei located within the medulla: 1. nucleus ambiguus 2. dorsal nucleus 3. nucleus of the tract of solitarius

14. nucleus ambiguus is the motor nucleus of the vagus nerve efferent fibers of the dorsal (parasympathetic) nucleus innervate the involuntary muscles of the bronchi esophagus heart stomach small intestine part of the large intestine afferent fibers of the nucleus of the tract of solitarius carry sensory fibers from the pharynx, larynx, and esophagus

15. the superior laryngeal nerve branches into internal and external branches the internal superior laryngeal nerve penetrates the thyrohyoid membrane to supply sensation to the larynx above the glottis and at the vocal cord the external superior laryngeal nerve innervates the one muscle of the larynx not innervated by the recurrent laryngeal nerve, the cricothyroid muscle

16. right vagus nerve passes anterior to the subclavian artery and gives off the right recurrent laryngeal nerve it loops around the right subclavian artery and ascends in the tracheo -esophageal groove, before it enters the larynx just behind the cricothyroid joint

17. left vagus does not give off its recurrent laryngeal nerve until it is in the thorax, where the left recurrent laryngeal nerve wraps around the aortic arch just posterior to the ligamentum arteriosum it then ascends back toward the larynx in the TE groove

18. Sup. Laryngeal N. : Arises form middle and inf. Vagal ganglion Internal laryngeal N. External laryngeal N Originates lateral to the cornu of hyoid Pierces thyrohyoid membrane Travels under mucosa in pyriform recess Sup. Br. – Mucosa of piriform fossa Middle Br – Musoca of ventricle Inf. Br. Mucosa of subglottic cavity Continue downwad on lat. Surface of inf. Constrictor Close relationship to Sup. Thyroid Artery where artery is clamped during thyroid lobectomy

19. Nerve supply of Larynx Superior Laryngeal Nerve- internal branch is sensory; supplies larynx above and at the level of vocal cords external branch supplies cricothyroid muscle Recurrent Laryngeal Nerve- motor branch supplies all muscles of larynx except the cricothyroid sensory branch supplies subglottis region

20. Intrinsic muscle of larynx muscles controlling the laryngeal inlet close the inlet – Oblique Arytenoid open the inlet – Thyroepiglottic muscles controlling the movement of vocal cords tense – Cricothyroid relax – Thyroarytenoid ( Vocalis ) adduction – Lateral Cricoarytenoid – Transverse Arytenoid abduction – Posterior Cricoarytenoid

21. Adductors of the Vocal Folds

22. Classification of Laryngeal Paralysis May be unilateral or bilateral and may involve Recurrent Laryngeal Nerve Superior Laryngeal Nerve Both Recurrent and Superior Laryngeal Nerve (combined or complete paralysis)

23. Causes of Vocal Cord Paralysis Malignant (25%) Surgical/Traumatic: (20%) Neurological (5-10%) Inflammatory Infectious Idiopathic (20-25%)

24. Malignant accounts for 25% of cases one half being caused by carcinoma of lung

25. Surgical/Traumatic: (20% cases) Thyroidectomy (partial or total) Neck dissection Carotid surgery Spinal surgery (with a neck incision) Heart surgery Mediastinoscopy Mediastinal mass (thymoma, lymph nodes, etc )

26. Long surgery of any kind (due to a long period of breathing tube placement) Esophageal surgery Pneumonectomy CABG Penetrating neck or chest trauma. Post intubation Whiplash injuries Posterior fossa surgery

27. Neurological (5-10%) Wallenberg syndrome (lateral medullary stroke) Syringomyelia Encephalitis Parkinsons Disease Poliomyelitis Multiple Sclerosis Myasthenia Gravis Guillian -Barre Syndrome Diabetes

28. Inflammatory: Rheumatoid Arthritis Infectious: Syphilis Tuberculosis Thyroiditis Viral

29. Idiopathic (20-25%): Sarcoidosis Lupus Polyarteritis nodosa Ortner's syndrome (left atrial hypertrophy)

30. Causes of Laryngeal Palsies Intracranial causes Cranial causes Neck Chest

31. Intracranial Head injury CVA Bulbar poliomyelitis Distinctive features Other neurological signs and symptoms due to combined paralysis of soft palate, pharynx and larynx

32. Cranial Fracture base of skull Juglar foramen lesions (Glomus tumours , Naspharyngeal Carcinoma) Skull base osteomyelitis Distinctive features Other cranial nerve palsies (IX,X,XI) Pharyngeal, superior and Recurrent Laryngeal nerve

33. Neck Thyroidectomy Thyroid Tumours Post Cricoid Carcinoma Malignant Cervical Lymphnodes Distinctive features Superior and Recurrent Laryngeal nerves involved

34. Chest Bronchogenic Carcinoma Cardiothoracic Surgery Aortic Aneurysm Mediastinal Lymphadenopathy Tracheal/ Oesophageal surgery Distinctive feature Involvement of Left Recurrent Laryngeal Nerve

35. Position of Vocal Cords

36. Position of Vocal Cords in Health and Disease

37. Recurrent Laryngeal Nerve Paralysis

38. Causes of Recurrent Nerve Paralysis

39. Recurrent Laryngeal Nerve Paralysis Unilateral results in ipsilateral paralysis of all intrinsic muscles except the cricothyroid vocal cord assumes a median or paramedian position and does not move laterally on deep inspiration

40. Clinical Features undetected as 1/3 rd of patients remain asymptomatic some patients may complain of change of voice voice gradually improves due to compensation by healthy cord which crosses the midline to meet paralysed one Treatment : generally treatment is not required

41. Bilateral RLN Paralysis Aetiology : condition is often acute in onset most common causes neuritis trauma (thyroidectomy)

42. Position of cords: as all the intrinsic muscles are paralysed the vocal cords lie in median or paramedian position due to unopposed action of cricothyroid

43. Clinical Features airway is inadequate causing dyspnoea and stridor but the voice is good dyspnoea and stridor become worst during exertion or during attacks of acute laryngitis treatment : Tracheostomy / vocal cord lateralization procedures

44. Vocal Cord Lateralization Procedures a im to move and fix the cord in lateral position to improve the airway Various procedures are Arytenoidectomy : can be done by external approach, endoscopic or by using LASER Thyroplasty type 2 Cordectomy: can be done through external, endoscopic or by using LASER Nerve muscle implant : sternohyoid muscle with its nerve supply is transplanted into the paralysed posterior cricoarytenoid to bring some movement

45. Superior Laryngeal Nerve Paralysis usually it’s a part of combined paralysis, isolated lesions are rare causes paralysis of cricothyroid muscle and ipsilateral anesthesia of the larynx above the vocal cord Causes : - thyroid surgery - thyroid tumors - diptheria Unilateral

46. Clinical Features: voice is weak and pitch can not be raised occasional aspiration may be present askew position of glottis as anterior commissure is rotated to the healthy side shortening of the cord with loss of tension as tension of the cord is lost , it sags down during inspiration and bulges up during expiration

47. uncommon condition both Cricothyroids are paralysed along with anesthesia of upper part of larynx Etiology: surgical accidental trauma neuritis neoplastic (pressure by metastatic lymph nodes) Clinical features: anaesthesia of larynx weak and husky voice aspiration causing cough and choking fits Bilateral

48. Treatment depends on cause, neuritis recovers spontaneously troublesome aspiration requires tracheostomy with cuffed tube and esophageal feeding tube epiglottopexy - operation to close laryngeal inlet to protect the lungs from repeated aspiration a reversible process

49. Combined (Complete) Paralysis Unilateral causes paralysis of all the muscles of larynx on one side except interarytenoid which receives innervation from the opposite side Etiology thyroid surgery is the most common cause may also occur in the lesions of nucleus ambiguus or that of the vagus nerve proximal to origin of SLN lesion may lie in medulla, posterior cranial fossa, jugular foramen or parapharyngeal space

50. Clinical features: all the muscles of larynx on one side are paralysed vocal cord will lie in cadeveric position healthy cords fails to compensate this causes hoarseness of voice and aspiration of liquids through the glottis cough is ineffective due to air waste

51. Treatment speech therapy procedures to medialise the cord injection of Teflon paste thyroplasty type 1 muscle or cartilage implant arthrodesis of cricothyroid joint

52. Bilateral both RLN and SLN are paralysed on both sides both cords lie in cadeveric position and there is total anaesthesia of the larynx Clinical features aphonia aspiration inability to cough bronchopneumonia

53. Treatment: tracheostomy epiglottopexy : epiglottis is folded backwards and fixed to the arytenoids vocal cord plication total laryngectomy

54. Congenital Vocal Cord Paralysis may be unilateral or bilateral unilateral is more common; due to birth trauma congenital anomalies of great vessels or heart bilateral paralysis may be due to Hydrocephalus Arnold-Chiari malformations Intracerebral hemorrhage during birth Meningocoele Nucleus ambiguus agenesis

55. THANK YOU!!!