Laryngeal
disease causing voice disorders
Vocal
nodules
These are known as singers’ nodules in adults and screamers nodules in
children (Fig. 43.44). They are fibrous thickenings of the vocal folds at the
junction of the middle and anterior third, and are the result of vocal abuse.
Speech therapy is therefore the preferred treatment and the lesions will resolve
spontaneously in most cases. Occasionally the nodules will need to be surgically
removed using modern microlaryngoscopic dissection or laser techniques.
Follow-up by the speech therapist is necessary until all of the underlying
errors in voice production are overcome.
Vocal
fold polyps
These are usually unilateral and may be associated with an acute
infective episode, cigarette smoking and vocal abuse
Laryngeal
papillomata
These occur mainly in children but can also present in adults. They are
most commonly found on the vocal folds but may spread throughout the larynx and
tracheobronchial airway (Fig. 43.46). They are caused by papilloma viruses and
need removal by laser surgery in order to maintain a reasonable voice and
airway. Antiviral treatment by such drugs as interferon remains of doubtful
value at present. Endoscopic laser surgery is the least traumatic way of
removing these lesions and should not produce scarring or cause implantation of
the papillomata elsewhere in the airway.
Acute
laryngitis
This often occurs in association with upper respiratory tract infections
in association with a cough and pharyngitis. It may, however, be localised to
the larynx, is usually viral and settles quickly if the patient rests the voice
during the active inflammation. Steam inhalations are soothing along with mild
analgesics but antibiotics are unnecessary. The condition should resolve in
2—3 weeks with voice care.
Chronic
laryngitis
Chronic laryngitis may be specific and can be caused by mycobacteria,
syphilis and fungi. Treatment is directed towards the causative organism. Nonspecific
laryngitis is common, and the main predisposing factors are smoking,
chronic upper and lower respiratory sepsis and voice abuse. In some cases the
laryngeal mucosa may become dysplastic,
Vocal
fold palsy
This may be unilateral or bilateral, but a unilateral left vocal fold
palsy is the commonest as a consequence of the long intrathoracic course of the
left recurrent laryngeal nerve which arches around the aorta and may be commonly
involved in inflammatory and neoplastic conditions involving the left hilum (Fig.
43.47).
Clinical
features
Unilateral recurrent laryngeal nerve palsy of sudden onset produces
hoarseness which is most notable for lack of volume to the voice and
occasionally may be associated with difficulty in swallowing liquids and
weakening of the cough. These symptoms may be short lived and the voice may
return to normal within a few weeks as the muscles in the opposite vocal fold
compensate and move it across the midline to meet the paralysed vocal fold which
usually lies in the paramedian position. Owing to this efficient compensation,
in slowly
Bilateral
recurrent laryngeal nerve palsy is an occasional and very serious complication
of thyroidectomy. Acute dyspnoea occurs as a result of the paramedian position
of both vocal folds which reduce the airway to 2—3 mm and which tend to get
sucked together on inspiration. In severe cases tracheostomy or intubation is
necessary immediately otherwise death occurs from asphyxia.
Investigation
of vocal fold paralysis is most easily encompassed nowadays by a CT scan from
skull base to diaphragm. This technique has replaced the multiple previous
investigations which were necessary and reveals most of the pathology which
may give rise to an undiagnosed vocal fold palsy. Approximately 20—25 per cent
of cases of vocal fold paralysis occurs without known pathology and spontaneous
recovery may occur. In unilateral vocal fold paralysis, where compensation does
nor occur, the paralysed fold may be medialised by injecting Teflon paste
lateral to the vocal fold and displacing it medially. Alternatively, a small
external operation on the thyroid cartilage may be undertaken in order to enter
the paraglotric space and displace the fold medially (thyroplasty). These
surgical procedures should be performed early if the cause is carcinoma of the
bronchus and the outlook of the patient is poor. When the pathology is unknown
it may be better to wait for a period of 1 year to see whether spontaneous
improvement occurs and to allow further recovery with the help of speech
therapy.
In
bilateral vocal fold paralysis the patients frequently require tracheostomy, but
surgery may be carried out to remove a small portion of the posterior aspect of
one vocal
Tumours
of the larynx
Benign tumours of the larynx are extremely rare and squamous carcinoma
of the larynx predominates over all others, being responsible for more than 90
per cent of tumours within the larynx. It is the commonest head and neck cancer
and almost always occurs in elderly male smokers. However, over the past two
decades the sex incidence has changed as a consequence of increasing smoking
amongst women, and in some areas they now make up more than 20 per cent of the
patients. The squamous epithelium of the vocal folds and the respiratory
epithelium of the supraglottis undergo dysplastic change stimulated by cigarette
smoking and other factors. The incidence of laryngeal cancer in the three
compartments supraglottis, glottis and subglottis varies around the world; the
glottis is generally the commonest site followed by the supraglottis (Fig.
43.48). True carcinomas of the subglottis are very rare and most are a
consequence of inferior spread from the glottis.
Clinical
features
The frequent glottic origin means that patients almost always present
with hoarseness. This is of great importance because if a diagnosis can be made
while the tumour is in the first stage, i.e. confined only to one vocal fold,
these cancers have more than a 90 per cent 5-year disease-free cure rare when
treated with radiotherapy alone. The cure rare drops dramatically once the
lymphatically rich supraglottis or subglottis is involved, owing to spread to
neck nodes. The appearance of more than one neck gland halves the overall
prognosis of the patient.
Investigations
Direct laryngoscopy, preferably a microlaryngoscopy, together with
Hopkin’s rod examination allows precise determination of the extent of the
tumour and biopsy confirms an exact histology (Table
43.13). CT and MRI
scanning give further details of the extent of larger tumours demonstrating
escape of the tumour outside the larynx and suspicious nodal involvement within
the neck which may nor be determined on clinical examination.
Treatment
Early supraglottic and glottic tumours stages I and II are optimally
treated with megavoltage radiotherapy where these facilities exist. Five-year
cure rates for stages I and II are
Advanced
laryngeal disease
Once the squamous carcinoma has caused fixation of the vocal fold or has
infiltrated outside the larynx into adjacent structures such as the thyroid
gland and strap muscles, some form of subtotal or total laryngectomy is required
to attempt to cure the disease. Total laryngectomy is frequently required when
radiotherapy fails (Figs 43.49-43.51).
After the larynx has been removed,
the remaining trachea is brought out on to the lower part of the neck as a
permanent tracheal stoma and the hypopharynx, which is opened at the rime of the
operation, is closed to restore the continuity for swallowing. Thus, the upper
aerodigestive and digestive tracts are permanently disconnected. Part or all of
the thyroid gland and associated parathyroid glands may also need to be removed
depending on
Vocal
rehabilitation
The loss of the larynx as a generator of sound does not prevent patients
speaking as long as an alternative source of vibrating can be created in the
pharynx. There are basically three ways of achieving this.
• An artificial device which produces sound when applied to the soft
tissues of the neck which is turned into speech by the vocal tract comprising
the tongue, the pharynx, oral cavity, lips, teeth and nasal sinuses. These
devices are usually battery powered.
• Voice production may be restored in some patients by learning to
swallow air into the pharynx and upper oesophagus.
• The most modern method is to gain use of the expired air from the
lungs to power speech which is achieved by placing a small valve through the
back wall of the tracheal stoma into the pharynx. This is a one-way valve
allowing air from the trachea to pass into the pharynx but it does not allow
food and liquid to pass into the airway (Fig. 43.53).
There is a variety of these
type of valves, the best known being the Blom—Singer valve which was developed
in the USA. With the restoration of expired air passing into the pharynx, the
segment of vibrating pharyngeal mucosa has a much greater quantity of air than
when it is simply swallowed into the pharynx and oesophagus, and this gives
an improved flow and quality to the speech of total laryngectomy patients.
These valves are common nowadays in laryngectomy patients in many countries
and they must not be confused with tracheostomy tubes. Like all foreign bodies,
the speaking valves are associated with minor complications such as the
formation of granulations, bleeding or leakage of pharyngeal contents.