Benign Vocal fold disorders
These disorders involve the mucosa lining the vocal cord. The free border of the vocal cord is responsible for voice production. At any given period of time about 50% of patients are affected by this disorder. These disorders are caused by vibratory trauma to the mucosa lining the free border of the vocal cord. Certain predisposing factors like Gastro esophageal reflux disorder, Smoking, Infections, Allergy may predispose this condition. This problem is most common among expressive and talkative personalities.
The following conditions are included under Benign vocal fold mucosal disorders:
1. Vocal nodules
2. Laryngeal polyps
3. Mucosal haemorrhage
4. Intracordal cysts
5. Mucosal bridges
6. Glottic sulci
If the affected pateint happens to be a singer, they may seek professional help because of voice limitation during singing, usually in the upper range. If the patient is a non singer then the patient may seek help with a little advanced lesion with a change in sound capabilities of the speaking voice.
Anatomy of the vocal fold:
Medial to lateral the membranous vocal fold is made up of squamous epithelium, Reinke's space (superficial layer of lamina propria) which is a potential space, vocal ligament (consisting of elastin & collagen fibres), thyroarytenoid muscle. Perichondrium & thyroid cartilage provide the lateral boundary.
Image showing vocal fold polyp
Image showing cut section of vocal fold
These vocal folds move as a whole between the extremes of abduction & adduction for breathing and phonation respcetively. The vocal fold mucosa (consisting of epithelium & superficial layer of lamina propria also known as Reinke's space) which covers the vocal folds is the chief oscillator during phonation causing continuous adduction. So it is the vocal fold mucosa which vibrates and not the vocal cord perse.
Hirano gave an excellent description of the ultra structure of the vocal cord. Acccording to him the body of the vocal fold is formed by muscle, which is covered by epithelium and superficial layer of lamina propria as the cover. The intermediate layers are formed by Collagenous and elastic fibres. These layers differ in their stiffness characteristics leading to different rates of vibrations during phonation. This whole process is known as decoupling. This decoupling allows the mucosa to oscillate with a degree of freedom from the ligament and muscle.
For phonation to occur pulmonary air is passed between adducted vocal folds. During this phase the vocal fold mucosa vibrates passively according to the length, tension and edge configuration determined by the intrinsic muscles, elastic recoil forces of the vocal fold mucosa.
How to evaluate these patients?
a. A good history taking is a must.
b. Assessment of vocal capabilities and limitations should be done.
c. Laryngeal examination.
History taking: should concentrate on the onset and duration of the vocal symptoms, exacerbating factors if any should be taken note of, symptom complexes must be studied, talkativeness of the patient must be ascertained, vocal commitments, other risk factors, severity of the disorder and vocal aspirations must be clearly noted.
Onset of symptoms: If the patient has complaints of frequently recurring bouts of vocal dysfunction, it could be safely assumed that it may be an exacerbation of a more chronic voice overuse disorder. These patients will benefit from voice training.
Exacerbating causes: Common symptoms are
1. Exaggeration of day to day variations of singing capabilitis.
2. Increased effort necessary for singing
3. There is clear reduction in vocal endurance
4. There is deterioration of ability for high frequency singing
5. There is delayed phonatory onset and air wastage
4. Certain drying medications prescribed for allergy
The following are the management options available:
2. Management of sinusitis
3. Management of acid reflex laryngitis : These patients have bad taste in the morning, scratching throat irritation, habitual throat clearing, erythema of arytenoid mucosa, and interarytenoid pachydermia / contact ulcers.
4. Voice rest.