do you ahve any information on the causes of partial paralysis to the vocal chords and what may have caused it, and the best therapy to have someone talking the way they used to.
thanks
Answer -------
It is somewhat unclear as to what is meant by "partial paralysis", but I assume it to mean paralysis of only one side of the larynx (voice box).
There are 2 primary innervations of the larynx (voice box). The superior laryngeal nerve is a branch of the vagus nerve which provides sensation to the mucosa lining the larynx and provides motor innervation to the cricothyroideus muscle which tenses the vocal cord muscle. A paralysis of this muscle typically results in a change in the range of the patients voice which may be subtle. It tends to be far more bothersome and serious in those who use their voice professionally (ie singers). Typically the physical examination will reveal a slight rotation in the orientation of the voice box on indirect mirror or endoscopic examination. The most likely cause of superior laryngeal nerve paresis is trauma such as from surgery, the most common cause being following thyroid surgery. There may be some benefit derived from speech therapy or voice therapy. There is no medical or surgical intervention that is used conventionally for this type of problem
The recurrent laryngeal nerve is also a branch of the vagus nerve and supplies most of the motor innervation of the larynx. If it is injured the vocal cord does not move. Like the superior nerve, there is a recurrent laryngeal nerve on either side of the larynx supplying the right and left vocal cords. If only one nerve is injured, the usual result is a weakness of the voice or breathiness of the voice. On physical examination, the physician can visualize movement of only one vocal cord. The paralyzed vocal cord typically rests displaced from the midline of the larynx. Thus the normal vocal cord may not come into full contact with the paralyzed vocal cord which is necessary to create the vibratory interaction necessary to generate normal vocal characteristics.
The most common cause of recurrent laryngeal nerve paralysis is also trauma, again surgical trauma being the most frequent etiology. Other causes of recurrent laryngeal n paralysis include tumors of the brain, tumors of the skull base where the vagus nerve exits into the neck, tumors of the throat or neck, or tumors in the chest. It is also not rare for isolated paralysis of a single vocal cord to have no known cause (some theories suggest viral infection.)
If the physician determines that the paralysis is permanent (usually a determination based upon time > 8-12mos following initial diagnosis), then surgical intervention for vocal rehabilatation can be considered. Surgical intervention is aimed at moving the paralyzed vocal cord back towards the midline of the larynx so that the opposite normal vocal cord can easily come into contact with the full length of the paralyzed cord to generate voice.
There are 2 basic conventional techniques to accomplish this: 1) By the injection of a "filling" substance into the muscle of the paralyzed cord. Most often Teflon paste is used, but other substances such as fatty tissue have also been used. This adds bulk to the paralyzed cord. The advantages of this technique are that it is fairly simple and readily available, as well as generally well tolerated. The disadvantages are that it can alter the natural vibratory characteristics of the paralyzed vocal cord making the resultant voice result somewhat unnatural. Additionally certain injected substances such as Teflon paste are considered permanent and can't be removed if too much is injected or if vocal function returns to normal.
2) By "laryngoplasty" techniques, whereby inert substance like medical grade silicon is implanted into the larynx through an external neck incision. This is designed to displace the paralyzed vocal cord towards the midline without disturbing the substance of the vocal cord muscle itself. It's main advantage is that it can restore a more natural voice than the injection technique. The disadvantage is that it is technically somewhat more difficult and requires an incision in the neck. This technique has recently enjoyed more widespread popularity amongst otolaryngologic surgeons in the US.
Both of these techniques are commonly done with the patient awake and the surgical area anesthetized with "numbing" medication. Also, surgical intervention for vocal paralysis typically is benefited by the addition of speech therapy intervention.
It should be noted that vocal cord paralysis can result in problems more serious than voice disorders. The vocal cords also help to protect the windpipe from aspiration of ingested substances or salivary secretions. If a vocal cord is paralyzed, it is possible for food or water to more easily pass into the windpipe and can subsequently cause pneumonia. If this situation is present, surgical intervention may be recommended even if it is too early to determine whether the condition is permanent. Also, if both vocal cords are paralyzed the voice may actually seem fairly normal, but breathing is often impaired since the vocal cords may interfere with the flow of air into the lungs.
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Steve Dankle, MD
Otolaryngology-Head and Neck Surgery
Milwaukee, Wis
NOTICE: OFCN is not engaged in the rendering of professional medical services. The information contained on this system or any other OFCN system should not supplant individual professional consultation. It is offered exclusively as a community education service. Advice on individual problems must be obtained directly from a professional.
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