What is sulcus vocalis?
Sulcus vocalis is a thinning or absence of a special layer of tissue, called the superficial lamina propria, which is the tissue covering the vocal cord requires to vibrate in order to produce sound. (Please click here for more information on normal voice function.) The lack of this tissue causes a divot in the vocal cord, which gives the disorder its medical name. Sulcus means “cleft” or “furrow” in latin.
It is not at all clear what causes sulcus vocalis. Some physicians think that this is a developmental disorder which occurs around adolescence, when the larynx grows to adult size. They point to the fact that sulcus is never seen in children, and that sulcus appears to be found more often in certain ethnic groups as evidence suggesting that it is developmental and possibly genetic. Others think that it is a long-term result of a vocal fold hemorrhage or cyst. They hypothesize that the healing after hemorrhage or a burst cyst causes the delicate tissue of the vocal fold to shrink and stiffen, creating the sulcus.
What are the symptoms of sulcus vocalis?
Sulcus vocalis causes a characteristic harsh, reedy hoarseness. People with sulcus frequently must exert unusual effort to produce voice, and find it more difficult to be heard over background noise. Because of the change in pitch which sometimes accompanies this disorder, men with sulcus sometimes complain that they are mistaken for women on the telephone.
Sulcus is usually a lifelong condition. So, even though the hoarseness may be worse on certain days, it is always present and the voice is never normal. Most people cannot recall ever having had a normal voice as an adult, although it is not rare to have had a normal voice as a child.
What does sulcus vocalis look like?
Sulcus vocalis has a very characteristic appearance of a furrow or a trench in the vocal fold, which can vary in depth.
Figure 1: The subtle groove on the edge of the vocal fold on the right of the image represents a sulcus vocalis.
It is usually found at the margin of the vocal fold, oriented parallel to its length. It can stretch the entire length of the vocal fold. The segment involved with the sulcus usually does not vibrate normally during voicing, a fact that is apparent on stroboscopic examination.
When the vocal folds are brought together to voice, the loss of tissue along the length of the folds usually causes a gap that is the shape of a spindle to appear between them.
Figure 2: Both of these vocal folds have a sulcus, visible as a white line, more pronounced on the left than the right. Both sulcus lesions are surrounded by considerable inflammation.
This gap causes air to leak out during voicing, which is probably one of the main reasons for the perception of increased effort needed to voice.
Typically, sulcus vocalis is subtle and commonly overlooked; the diagnosis is an extremely hard one to make. It is routinely missed by examiners who do not use stroboscopy, since so much depends on seeing that part of the vocal fold is not vibrating normally.
How is sulcus vocalis treated?
The treatment of sulcus vocalis is controversial. The main difficulty is that there has been no perfect substitute for the missing superficial lamina propria tissue. Efforts to create a substitute in the laboratory are underway and may be ready for clinical use in the near future.
Some advocate that the strip of sulcus should be completely removed and that neighboring normal tissues should be drawn in to cover the gap left by the removal. While the theory is sound, in practice this maneuver typically results in scarring with hoarseness equal to or even worse than that caused by the sulcus itself.
Figure 3: There is a sulcus along the edge of both vocal folds which gives the appearance of tissue being scooped out of the vocal fold. This type of sulcus that involves the whole length of the vocal folds is a special type known as a sulcus vergeture.
Other physicians suggest that the vocal fold cover should be lifted up and a new tissue should be inserted to keep it apart from deeper tissues. Fat from elsewhere in the body, collagen and other substances are typically used. Results are inconsistent and somewhat unpredictable, although sometimes they can be quite good. It is hoped that the development of bioengineered superficial lamina propria tissue, currently being researched, will improve the results obtained with this approach.
Finally, some surgeons, displeased by the unreliability of either approach, settle for injecting the vocal fold to close the spindle-shaped gap created by sulcus. They and their patients accept that this is only a partial solution, but that it might be the best that can be done for now.