Selective Laryngeal Adductor Denervation-Reinnervation (SLAD-R)

Selective Laryngeal Adductor Denervation-Reinnervation (SLAD-R) is a newer surgical treatment for adductory spasmodic dysphonia, introduced by Dr. Gerald Berke of UCLA^[1] in the late 1990s. During the procedure, the anterior branch of the recurrent laryngeal nerve, which supplies the thyroarytenoid (TA) and lateral cricoarytenoid (LCA) muscles—both essential for voice production—is severed. This eliminates the strained, squeezed quality of the voice, as well as the characteristic “catching” or “cutting out,” of speech. However, without additional intervention, the voice would remain permanently weak, or dystonic nerve impulses could reestablish unwanted connections.

To avoid this, SLAD-R includes a simultaneous reinnervation process. A branch of the ansa cervicalis nerve, which typically serves less critical neck muscles, is harvested and connected to the severed nerve. This helps restore function while preventing unwanted nerve regeneration. However, the reconnection process takes time, leaving patients with a breathy, whispery voice for three or more months before some muscle tone and vocal volume return.

While many patients experience long-term improvement, others may redevelop spasms and require additional treatments, such as Botox injections or vocal cord muscle debulking. The effectiveness of SLAD-R varies, and outcomes are difficult to predict for any individual. It would be helpful to have an online source of voice recordings of many patients at various times: before SLAD-R surgery, and also at 3 months, 6 months, 1 year, and 2 years after surgery.

Differential Re-Innervation after SLAD-R Surgery

Six years post SLAD-R (1 of 4)

Six years after SLAD-R performed elsewhere. Note that re-innervation appears greater for left (right of photo) than right (left of photo) thyroarytenoid (TA) muscle. Signs of continuing atrophy of the TA muscle within the right cord (left of photo) include capacious ventricle (‘V’); absence of “conus” (‘C’) bulk below the free margin (see contrast between /–/ on both sides); slight concavity or bowing of the free margin; and narrower band of the vocal cord itself that we sometimes refer to as the “spaghetti-linguini” larynx.

TA + LCA muscles (2 of 4)

While TA is more recovered on the left (right of photo) as seen in photo 1, here we see that the lateral cricoarytenoid (LCA) muscle has recovered more on the right (left of photo). At the prephonatory instant, the failure of the left (right of photo) vocal process to turn to the midline indicates continuing weakness of the LCA muscle.

Greater amplitude of right cord (3 of 4)

Under strobe illumination, open phase of vibration shows greater amplitude of right cord (left of photo), consistent with the atrophy of the permanently somewhat weak TA muscle seen in photo 1.

Patient has returned to Botox (4 of 4)

Closed phase of vibration. A few years after SLAD-R, this man’s spasms recurred sufficiently that he has resumed Botox injections.

SLAD-R Findings in Spasmodic Dysphonia

This man has had longstanding laryngeal dystonia causing adductory spasmodic dysphonia. More than a year before these photos, he underwent SLAD-R on the left side (right of photo). The left cord moves normally, and one can see full recovery of the LCA (lateral cricoarytenoid) muscle, but the TA (thyroarytenoid) muscle is atrophic and flaccid.

Angle of Abduction post SLAD-R Surgery — Angle of Abduction (1 of 5)

A year after SLAD-R, the angle of abduction (legs of the “V”) is the same bilaterally due to equal function of the PCA (posterior cricoarytenoid) muscle, not affected by the surgery. The margin of the folds (dotted lines) appear similar. But the bulk of the left thyroarytenoid muscle as manifested in the conus (bulge below the margin) appears to be less on the left (right of photo) than on the right (left of photo). The conus is also mildly flattened, as well. See the difference as marked by the bracketed lines.

Concave margin demonstrates TA muscle atrophy — Concave Margin (2 of 5)

As the cords approach approximation, the vocal processes are both beginning to point equally towards each other, suggesting that both LCA (lateral cricoarytenoid) muscles fully functional. However, the margin of the left cord appears to be subtly more concave than the right, suggesting mild TA (thyroarytenoid) muscle atrophy. (Compare dotted lines.)

Lateral buckling of left vocal cord — Lateral buckling (3 of 5)

During phonation under standard light, the cord margins are both blurred due to vibration, but the left side (right of photo) is buckling laterally, consistent with atrophy/flaccidity.

Mild bowing of the left vocal cord — Mild bowing (4 of 5)

Under strobe light, at maximally closed phase of vibration. This view again suggests mild bowing of the left cord (right of photo).

Greater amplitude due to atrophy and flaccidity — Greater amplitude (5 of 5)

The open phase of vibration shows much greater amplitude (lateral excursion) of left cord oscillation (lower right of photo) than on the right vocal cord (upper left of photo). Furthermore, the vibratory wave of the left cord is much greater, also consistent with atrophy/flaccidity.

One Man’s Experience Over Time with SLAD-R

SLAD-R is a surgical alternative to ongoing “botox” injections for treatment of adductory spasmodic dysphonia. The surgery involves intentionally cutting the nerves that close the vocal cords for voice and reconnecting a different nearby nerve supply (reinnervating the nerves).

This surgery requires the patient’s willingness to endure an extremely breathy voice for many months after the procedure, while awaiting reinnervation.

How Effective Is SLAD-R in Treating AD-SD?

SLAD-R compared to high quality botulinum toxin injections.

Read Article

SLAD-R: A New Surgical Treatment for AD-SD ^[1]

Gerald S. Berke, MD et al.

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Selective Laryngeal Adductor Denervation-Reinnervation (SLAD-R)

Differential Re-Innervation after SLAD-R Surgery

Six years post SLAD-R (1 of 4)

TA + LCA muscles (2 of 4)

Greater amplitude of right cord (3 of 4)

Patient has returned to Botox (4 of 4)

SLAD-R Findings in Spasmodic Dysphonia

Angle of Abduction (1 of 5)

Concave Margin (2 of 5)

Lateral buckling (3 of 5)

Mild bowing (4 of 5)

Greater amplitude (5 of 5)

One Man’s Experience Over Time with SLAD-R

How Effective Is SLAD-R in Treating AD-SD?

SLAD-R: A New Surgical Treatment for AD-SD [1]

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SLAD-R: A New Surgical Treatment for AD-SD ^[1]