MANAGEMENT OF NEUROLOGIC DISEASE OF THE VOCAL CORD- PARALYSIS
Neurologic disease of the vocal cords embraces both conditions that weaken or paralyze the vocal cords or cause increased tone. In this section unilateral or one sided paralysis is featured.
The vocal cords are a pair of tissue bands, attached at the front of the voice box (larynx) just below the Adam’s apple. As a widening inverted “V” the vocal cords attach each to a mobile cartilage called the arytenoid. This cartilage sits on a slippery slope of cartilage and is held in place by 4 muscles. It is the neural organization of these muscles that slides the vocal cords to meet in the middle or move away. Thus, this is a valve and it opens to breathe, and closes to protect the lung during swallowing, produce an effective cough and create sound for a voice.
Loss of the nerve (recurrent laryngeal nerve) on one or both sides of the larynx leads to paralysis of the vocal cords. This nerve has a long course from the brain, through the neck, into the chest to turn and reenter the neck to reach the larynx. Disease, trauma or tumor can destroy this nerve anywhere along this extremely long course.
One sided nerve loss paralyzes that vocal cord from being able to move to the midline and meet its mate from the other side. The valve action is lost and with it is the ability to cough and project the lower airway and to produce sound as voice.
While it is problematic to be able to regain movement in a one sided paralyzed vocal cord that vocal cord can be moved and fixed in the midline so the opposite, and mobile cord can still meet it. That restores the valve function and even voice quality.
The adoption of high tech, modern materials as implants has made restitution of vocal cord valvular function possible and very successful. Some of the procedures can be done in the office under topical or “sprayed on” anesthesia. Using a flexible endoscope and attached camera, and the injection is begun while following the progress on the monitor. Small amounts are added as the patient is asked to phonate until the vocal cord is moved to a midline position where the opposite cord can meet it. The voice will have a full volume. The procedure takes about 1-2 minutes to complete and the patient is ready to leave. Injections such as this can last up to 3 years.
MANAGEMENT OF NEUROLOGIC DISEASE OF THE VOCAL CORD- OFFICE TREATMENT OF SPASTIC AND OTHER TREMOROUS MOVEMENT DISORDERS OF VOCAL CORD MOVEMENT
Botulinum toxin (Botox) is used in the treatment of overly active movement of the vocal cords and how they cause abnormal sounding voice. In some cases this is random breaks or stops in the free flow of speech. This presents as a spectrum from a mild disorder to inability to speak at all. Another disorder is vocal tremor where a shaking, regular series of voice breaks disrupts continuous speaking. A simple injection of the vocal cords with botox can alleviate this symptom for up to 6 months and then must be repeated. These injections can be done in the office.
The procedure is very precise, injecting a set, carefully measured volume under both visual and electromyographic (EMG) control into a specific point of the vocal cord. This control allows for a very predictable result that can actually be adjusted to the patients needs. To accomplish this in the office with this level of precision requires topical (local) anesthesia such that the procedure is essentially painless and allows use of a camera mounted on a flexible endoscope to display the procedure on a monitor.
A special, very fine EMG, is placed just below the voice box. It is monitored as it is maneuvered to enter each vocal cord just beneath the vocal process. The EMG picks up electrical activity within the tissue indicating that the correct muscle has been entered. At this point the injection is done. The lasts less than a minute. The patient is ready to leave.
The effects begin in about 24 hours and last for up to 6 months and then have to be repeated. The same treatment works for both the spastic or spasmodic voice and for vocal tremor.