Since long before I started studying speech pathology and specializing in voice, there has been controversy about the classification of vocal fold lesions. Strikingly, there are vastly different opinions between the ENT’s I have worked with over the years in terms of what to call the various lumps and bumps we see in laryngeal stroboscopic examinations. I get many questions from patients and other interested people about this. So, I thought it would be helpful to outline some of the professional considerations we take into account in attempting to classify vocal fold lesions.
As there are a number of different considerations, I will break this discussion down into several parts. In this post, I will discuss the question of bilateral versus unilateral lesions.
In medical terminology, unilateral refers to something that is present or occurring on one side of a structure. Bilateral means something is present or occurring on both sides of a structure. In the larynx, there are two vocal folds positioned in a “v” shape at the top of the trachea (breathing tube). The top of the “v” opens when you breath and closes when you make sound. If there is a unilateral lesion of the vocal folds, that means there is a lump or bump on one vocal fold. If the lesions are bilateral, there are lumps or bumps on both of the vocal folds.
Prior to common availability of stroboscopic examination of the larynx, the only way a physician could visualize the vocal folds outside of the surgical suite was with a small dental mirror. The image was small, poorly lit and could not reveal what happens to the vocal fold cover during vibration.
It is important to recognize that the inability to see the movements of the vocal fold cover as it vibrates makes it virtually impossible to understand the dynamics involved in the sound. Since the vocal folds vibrate faster than the human eye can see, this information is lost in the absence of a stroboscopic examination. Historically, this was a serious limitation on the ability of physicians to specify lesion types during an office visit.
In that era, any time a physician saw benign, bilateral lesions (non-cancerous bumps opposite each other on each vocal fold) the patient would be said to have “nodules.” Given the information they had, the presence of lesions across from each other on each vocal fold was assumed to be the result of impact stress force during phonation (strain in speaking or singing). The unfortunate side effect of this assumption was the implication that the patient was somehow responsible for their condition; that they had “done something” to injure themselves. If the patient was involved in singing, even on a peripheral or amateur level, they were informed that cause was singing incorrectly. To this day, I receive some physician orders with the diagnosis of “singer’s nodules.”
The availability of stroboscopic imagery for voice allowed us to see the details of vocal fold lesions and their dynamics. What clinicians began to appreciate was the variety these lesions represented. We are now able to see subtle asymmetries and differences in consistency or stiffness in the lesions on one vocal fold versus the other. We are able to witness the impact that these factors have on the vibration of the vocal folds.
One conclusion drawn from this new information is the fact that a lesion can be created on the vocal fold by hitting a lesion on the opposing vocal fold. That is, there may be a lesion on say, the left vocal fold, but the right fold develops a reactive lesion from hitting the lesion on the other side. This is very different than saying a person is misusing their voice and therefore developed bilateral vocal fold nodules.
It is significant for treatment when it becomes clear that one lesion is in fact a unilateral polyp or cyst and the other lesion is a reactive nodule. In treatment then, you would not be surprised if the reactive lesion disappears with voice therapy alone, while the primary lesion needs surgical removal.
So, the question of whether a patient has bilateral lesions of the same type or bilateral lesions of different types is diagnostically significant in terms of discerning polyps, nodules and cysts. It may guide voice therapy treatment as well. Prognosis is certainly impacted by this distinction. It can no longer be assumed that simply viewing bilateral lesions is indicative of nodules, while polyps and cysts are mostly unilateral. If the detail of the vocal fold is not examined in great enough detail to distinguish between the two, the likely outcome will be suboptimal.
Stay tuned for the next post in this series, which will discuss distinguishing polyps versus nodules based on the presence or lack of a surrounding capsule.