Surgical procedures have been used to treat SD for more than thirty years. The majority of the operations are designed for patients with adductor spasmodic dysphonia (AdSD) and few surgical options exist for abductor spasmodic dysphonia (AbSD). This section only discusses operations designed to treat AdSD. The goal of these procedures is similar to that for botulinum toxin: weaken the muscles that are closing too tightly in order to produce a relaxed and fluent voice. This can be accomplished in two distinct ways.
The first involves adjusting the laryngeal supports to physically separate the vocal folds. The second involves adjusting the nerve input or muscle tension by physically altering the muscles or nerves going to the larynx.
Dr. Isshiki of Japan pioneered the operative procedure called thyroplasty, which entails separating the vocal folds. Most commonly used to treat vocal fold paralysis, thyroplasty has several variations, one of which has been performed on some people with SD.
In Type II thyroplasty, also called a lateralization thyroplasty, the surgeon physically separates the vocal folds to limit their ability to contact one another. The operation is typically performed under local anesthesia with sedation so that the patient can talk while the surgeon adjusts the vocal fold distance. The result is a slightly weaker voice with improved fluency. Although some people have reported success with the outcomes of this particular procedure, Chan, et. al, in a 2002 review of this technique, reported short-lived effects, with more than two-thirds of patients returning to a baseline voice at 12 months. Recovery time and risks are minimal, making this operation a reasonable option despite the variability of results.
The first nerve-related operation for SD is credited to Dr. Herbert Dedo of San Francisco. He published several reports of his patients’ experiences in the 1970s after a unilateral (one-sided) nerve resection.
Dr. Dedo cut and removed a portion of the nerve that goes from the brainstem to the larynx, known as the recurrent laryngeal nerve. Cutting this nerve weakened one side of the larynx. Some patients received significant improvement, but other doctors found the improvement came at the expense of a different type of hoarseness associated with the loss of one nerve. Many patients also had recurrence of spasms. Several variations of this recurrent nerve operation have been performed over the decades with variable results.
Selective Laryngeal Adductor Denervation-Rennervation (SLAD-R)
The Selective Laryngeal Adductor Denervation-Rennervation (SLAD-R) operation is an enhancement of the original procedure performed by Dedo. This bilateral operation, popularized by Dr. Gerald Berke, focuses on treatment of the tiny nerve branches that go to the individual muscles involved in AdSD. First, the surgeon cuts the nerves to the muscles on both sides of the larynx, thereby weakening the muscles. This is known as denervation and involves the recurrent laryngeal nerve being cut away from the thyroarytenoid (TA) and lateral cricoarytenoid (LCA) muscles. Next, the surgeon connects an unaffected nerve to the stumps of the nerves severed in denervation. This process, known as reinnervation, prevents the weakened muscles from atrophy and also blocks the denervated nerve branch from reconnecting and the spasms from returning.
The procedure is accomplished through an incision in the neck and creating a small window into the laryngeal cartilage to expose the underlying nerves and muscles. An operating microscope is often used to identify and suture the tiny nerve branches. Great care is taken to preserve the back part of the cartilage that protects the nerve branches to the breathing muscles. The procedure takes three or four hours and is performed under general anesthesia. A hospital stay is usually required.
Over the past 15 years, the results of SLAD-R operation have been quite favorable, with more than 80 percent of patients happy that they had the surgery. Although Dr. Berke and his associates have operated on the largest number of patients, surgeons in other centers also have performed the operation successfully. Patients report a very breathy voice for about two to four months following the procedure with their voices then getting progressively stronger over a year of healing. Many patients report a permanent stable resolution of their voice breaks. However, a handful of patients have reported poor voice outcomes with permanent alteration of their voices. Very few patients have had recurrence of symptoms and returned to BTX treatment.
Recently, surgeons have reported their experience with other operative procedures that treat the spasming muscle directly. The small number of these operations makes it difficult to generalize their outcomes. In one such procedure, the surgeon weakens the TA and LCA simply by cutting them. It is performed through the skin of the neck under local anesthesia with sedation or through the mouth under general anesthesia with a laser. The muscles are cut or removed, which relaxes the spasms and removes the voice breaks associated with SD. Risks of this operation are small, but, as with all SD treatments, medical or surgical, they may result in hoarse voice or swallowing difficulty.