Voice Disorders Due to Nerve Damage

1. Voice Disorders Due to Nerve Damage

2. Vocal fold paralysis • Inability of one or both folds to move because of the lack of innervation to particular intrinsic laryngeal muscles • lesion may be peripheral or central; most VFP are due to peripheral lesions e.g., damage to the SLN or RLN • Brodnitz (as far back as 1967) “most frequent cause…during thyroid operations”

3. Superior Laryngeal Nerve Paralysis • If bilaterally damaged, pt can not elevate pitch • if unilateral, one fold elongates for pitch change while the other is unaffected; results in hoarse voice, lacking pitch variation, and adequate loudness • result is an “oblique glottis”

4. Recurrent Laryngeal Nerve Paralysis • Can be unilateral or bilateral • Adductor paralysis: involved fold(s) can not be adducted to the central position • Abductor paralysis: paralyzed fold can not move laterally • paresis

5. Adductor Paralysis • Bilateral adductor form • folds are open; usually in a paramedian position • pts is aphonic • Unilateral Adductor form • involved fold is in paramedian position; complete glottal closure is not possible • air is wasted during phonation • breathy, hoarse vocal quality

6. Unilateral adductor con’t • Tx.directed at increasing the “sharpness” of glottal attack possibly with effort closure • sometimes will give the pt. a stronger,better voice • Medical management: electrotherapy to stimulate the fold (muscle and nerve) and phonosurgery

7. Unilateral Adductor Paralysis, con’t • Boone: if bilateral, voice tx is rarely effective • medical tx: surgical repositioning, phonosurgery • Spontaneous recovery period: approximately 6-9 months; varies physician Vs. behaviorists

8. Abductor Paralysis • Unilateral abductor: results in the paralyzed fold lying near the midline • some cases may abduct laterally to the intermediate position, but never full abduction as in deep inhalation • pt complains more about SOB than dysphonia • Primary symptom: usually impaired respiration with little/no voice change

9. Bilateral Abductor Paralysis • Both folds are relatively fixed in an adducted midline position • immediate surgery required to preserve the airway • initially requires tracheotomy, then a second procedure to reposition the folds • voice tx may be prescribed

10. Therapy for vocal fold paralysis • Bilateral adductor: May try effort closure • often result of central brain stem lesion (Boone) • can have cerebral dysfunction, e.g., weakness of the tongue, palate or pharynx • Boone says tx is “probably contraindicated” • Surgery only if bilateral damage secondary to PNS damage, not CNS

11. Unilateral Adductor Paralysis • Usually due to unilateral involvement of RLN • Perceptual symptoms: marked dysphonia, severe breathiness. Note: breathiness is dependent upon the degree of glottal closure. • Mgmt determined by MD/DO; must preserve the airway.

12. Airway considerations • Laryngeal valving; biologic function • silastic injection may be require to protect the airway

13. More tx considerations • Boone: best voice is achieved with treatment that stresses increased breath control, increased hard glottal attack (why??) and pushing exercises

14. Tx for Unilateral Abductor Paralysis • One fold remains fixed in a central, adducted position • phonation is rarely effected since both folds approximate well • quiet breathing is unaffected; during physical activity breathing becomes difficult due to narrowed airway

15. Unilateral Abductor tx con’t • Surgery unlikely as the airway will be preserved • Generally voice tx requires goo vocal hygiene, maintenance of a relaxed, open vocal tract

16. Tx for adductor forms(Boone, Stemple,Aronson and Case) • Prognosis is better for pts with static lesion rather than degenerative PNS diseases • Unilateral forms are better tx risks than bilateral • Idiopathic VFP may experience spontaneous voice return • masks as a conversion aphonia: SEE ENT!

17. More Boone, et al. • Tx based upon the pt’s potential to compensate by means of adduction of the intact fold • Aronson: effort closure, dec. musculoskeletal tension, digital manipulation of the affected fold, gravity, head turns

18. Considerations for surgical augmentation • Typically “polytef” a mixture of 50% glycerin base • inserted into the lateral margin of the fold

19. Case: reasons for teflon laryngoplasty • Only if affected fold is in the paramedian, intermediate or abducted position AND unable to move toward the midline • inject one cord if bilateral bowing due to SLN paralysis; bowing in the midglottic space when adduction/abduction are “normal”

20. Case, con’t • Done after cordectomy, hemilaryngectomy or blunt laryngeal trauma when glottal incompetency occurs due to removed or damaged tissue • Done when arytenoidectomy produces glottic incompetency

21. Contraindications of Teflon laryngoplasty • Not in majority of bilateral add. Paralyses as the procedure requires one competent v.f. to work against the displaced fold • can’t be done if v.f.s are paralyzed due to CNS lesion producing dysarthria and bilateral involvement • NOT done to add mass to v.f. to lower fundamental frequency

22. Contraindications, con’t • Not done before 6 mo after onset except in the case of CA-caused paralysis • may experience spontaneous recovery during the 6 mo period • Not done if pt is psychologically unstable • Not done for dysphonia from myasthenia laryngis or hypogenesis of the vocalis muscle

23. More contraindications • Not done for minor defects in the glottic area until vocal rehab via voice tx has been attempted • Should not be done in an attempt to move the arytenoid medially; only vocalis tissue should be moved by displacing the anterior 2/3 of the glottis

24. Phonosurgery Any surgery designed primarily for the improvement or restoration of voice

25. Phonosurgery options • Laryngeal injection techniques • Laryngeal framework surgery • Laryngeal innervation • Microsurgery of benign lesions • Laser • Instrumental

26. Evaluation • History and physical exam • Videostroboscoy • Aerodynamic analysis • Maximum phonation time (MPT) • Mean air flow rate (MFR) • Acoustic analysis • Laryngeal manual compression tests

27. Aerodynamic Analysis • Max phonation time • indication of glottic competence • influenced by vital capacity • use sustained /a/ • women: 14-40 seconds • men: 15-62 seconds

28. Aerodynamics, con’t • Mean air flow rate • indicator of degree of glottic closure • Norm values • women: 43-193 cm3/sec • men: 46-222 cm3/sec

29. Lateral Compression Test • Most valuable in incomplete glottic closure • Unilateral RLNP • Vocal Fold atrophy • Sulcus vocalis • Sulcus vergeture • Sustain phonation using /o/ • Type I thyroplasty

30. Injection Techniques in Vocal Fold Paralysis • 1911- Wilhelm Brunings • Paraffin injection • Brunings syringe (0.05 ml) • Paraffinoma < 46 degrees C • 1957 Godfery Arnold • Diced autogenous septal cartilage paste • 1976-Lewy--teflon injection; 1039 procedures over 24 y ears; 96% improvement

31. Laryngeal Framework Surgery • 1915-Erwin Payr: first thyroplasty, anteriorly based flap of the thyroid cart. • 1942-Yrho Meurman: implanted costal cartilage via laryngofissure • 1955-Odd Opheim: superior thyroid ala • 1965- Tschiassny:approximate cricoid and thyroid cartilage to increase vocal pitch • 1974-Isshiki thyroplasty

32. Laryngeal Framework SurgeryAdvantages • Less vocal fold trauma • Vibratory structure is preserved • Reversible • Intraoperative • Early voice restoration

33. Laryngeal Framework SurgeryIndications • Unilateral RLNP • Vocal fold atrophy • Suclus vocalis • Sulcus vergeture

34. Laryngeal Framework SurgeryIsshiki Classification • Type I Medialization • Type II Lateralization • Type III Shortening • Type IV Lengthening

35. Combined Lateral Compression and Cricothyoroid Approximation • Evaluates imperfect glottic closure due to VF atrophy and decrease in tension and stiffness • RLNP and presbylaryngis • CN X injury above the nodore ganglion • Thyroplasty Type I and IV or arytenoid adduction

36. Arytenoid Adduction • Procedure of choice when the glottic aperture is wide and the immobile vocal fold is at a higher level posteriorly • Technically difficult • Anterior placement-- junction of anterior and middle third of the thyroid ala • Open cricoarytenoid joint

37. Cricothyroid Approximation • Evaluates pitch disorders • Sustained /o/ • Compression should rise pitch • Thyroplasty type IV

38. Vocal Fold Medialization • Intrafold injection: transoral via indirect, transoral with direct or transcutaneous through the cricothyroid space • surgical augmentation • medial shift of the thyroid • rotation of the arytenoid

40. Vocal Fold Lateralization • Laterofixation of the VF: move the vocal process laterally • Arytenoidectomy: removal of the arytenoid to widen the posterior glottis

41. Vocal Fold Tensing • To raise pitch • Cricothyroid approximation: permanent approximation of the cricoid arch to the thyroid cart. Anteriorly • stimulates the cricothyroid m. • done under local to monitor pitch • anterior commissure advancement: intent is to stretch the VF by moving the anterior commissure anteriorly

42. Vocal Fold Slackening • Reduce the tension of the VFs • move the anterior commissure posteriorly, toward the arytenoids