Download Voice Disorders Due to Nerve Damage

Voice Disorders Due to Nerve
Damage
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”
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”
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
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
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
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
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
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
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
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.
Airway considerations
• Laryngeal valving; biologic function
• silastic injection may be require to protect
the airway
More tx considerations
• Boone: best voice is achieved with
treatment that stresses increased breath
control, increased hard glottal attack
(why??) and pushing exercises
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
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
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!
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
Considerations for surgical
augmentation
• Typically “polytef” a mixture of 50%
glycerin base
– inserted into the lateral margin of the fold
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”
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
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
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
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
Phonosurgery
Any surgery designed primarily for
the improvement or restoration of
voice
Phonosurgery options
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Laryngeal injection techniques
Laryngeal framework surgery
Laryngeal innervation
Microsurgery of benign lesions
– Laser
– Instrumental
Evaluation
• History and physical exam
• Videostroboscoy
• Aerodynamic analysis
– Maximum phonation time (MPT)
– Mean air flow rate (MFR)
• Acoustic analysis
• Laryngeal manual compression tests
Aerodynamic Analysis
• Max phonation time
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indication of glottic competence
influenced by vital capacity
use sustained /a/
women: 14-40 seconds
men: 15-62 seconds
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
Lateral Compression Test
• Most valuable in incomplete glottic closure
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Unilateral RLNP
Vocal Fold atrophy
Sulcus vocalis
Sulcus vergeture
• Sustain phonation using /o/
• Type I thyroplasty
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
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
Laryngeal Framework Surgery
Advantages
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Less vocal fold trauma
Vibratory structure is preserved
Reversible
Intraoperative
Early voice restoration
Laryngeal Framework Surgery
Indications
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Unilateral RLNP
Vocal fold atrophy
Suclus vocalis
Sulcus vergeture
Laryngeal Framework Surgery
Isshiki Classification
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Type I
Type II
Type III
Type IV
Medialization
Lateralization
Shortening
Lengthening
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
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
Cricothyroid Approximation
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Evaluates pitch disorders
Sustained /o/
Compression should rise pitch
Thyroplasty type IV
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
The images below depict the medialization thyroplasty
procedure. The image on the left shows the placement of the
shim in the thyroid cartilage. The coronal image on the right
demonstrates how this shim, when correctly placed, an help
push a motion-impaired vocal fold medially.
Vocal Fold Lateralization
• Laterofixation of the VF: move the vocal
process laterally
• Arytenoidectomy: removal of the arytenoid
to widen the posterior glottis
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
Vocal Fold Slackening
• Reduce the tension of the VFs
– move the anterior commissure posteriorly,
toward the arytenoids