Vocal cord paralysis happens when one or both vocal cords can’t move because the nerve controlling them is damaged or disrupted. Your vocal cords (also called vocal folds) are two flexible bands of muscle tissue inside your voice box. They open when you breathe, close when you swallow, and vibrate together to produce sound. When paralysis strikes, the affected cord stays fixed in one position, which can weaken your voice, make swallowing difficult, and in some cases compromise your airway.
How the Nerve Damage Works
Vocal cord movement depends on a nerve called the recurrent laryngeal nerve, a branch of the vagus nerve that runs from the brain down through the neck and chest before looping back up to the voice box. This long, winding path makes the nerve vulnerable to injury at many points along the way. When the nerve is damaged, the electrical signals that tell your vocal cord muscles to open and close are weakened or cut off entirely.
A paralyzed vocal cord typically becomes shortened, loose, and positioned off to the side. Because it can’t press firmly against the other cord, a gap forms between them. Air leaks through that gap when you try to speak, producing a breathy, weak voice. The same gap also means the vocal cords can’t fully seal your airway when you swallow.
One Side vs. Both Sides
Most cases involve just one vocal cord (unilateral paralysis). The main problems are voice quality and, to a lesser extent, swallowing. Your voice sounds rough and breathy, tires out quickly, and you may feel short of breath while talking because so much air escapes. Breathing itself is usually not noticeably affected, since the working cord can still open the airway enough. Swallowing problems, when they occur, tend to involve thin liquids like water or coffee, which slip past the gap and trigger coughing.
Bilateral paralysis, where both cords are affected, is less common but more dangerous. If both cords are stuck near the midline, the airway opening becomes very narrow. Paradoxically, the voice can sound almost normal in this situation because the cords are close enough together to vibrate. But the tradeoff is stridor, a high-pitched, strained sound during breathing that signals the airway is partially blocked. Bilateral paralysis sometimes requires emergency treatment to secure the airway.
What Causes It
Surgery is the leading cause. Thyroid and parathyroid operations pose the highest risk because the recurrent laryngeal nerve runs directly behind the thyroid gland. Between 118,000 and 166,000 thyroidectomies are performed in the U.S. each year. Roughly 1 in 10 patients experiences a temporary nerve injury afterward, and up to 1 in 25 develops longer-lasting voice problems. Permanent vocal cord paralysis occurs in fewer than 1% to 5% of cases, depending on the complexity of the surgery.
Anterior cervical spine surgery is another significant contributor. Studies report vocal cord paralysis in up to 24% of patients immediately after the operation, though most of these cases resolve. Reoperation and right-sided surgical approaches increase the risk. Other surgical causes include lung surgery, heart surgery (including coronary artery bypass and aortic valve replacement), esophageal procedures, and even prolonged intubation from a breathing tube.
Outside the operating room, the most common causes include tumors pressing on the nerve (particularly lung or thyroid cancers), viral infections that inflame the nerve, and idiopathic cases where no clear cause is ever found. A rare condition called Ortner’s syndrome can also cause paralysis when an enlarged heart structure compresses the nerve.
Symptoms to Recognize
The hallmark symptom is a voice change. It may sound breathy, hoarse, or noticeably quieter than before. You might find yourself running out of breath mid-sentence or needing to take frequent pauses while speaking. Your voice may fatigue easily, getting worse as the day goes on or during long conversations.
Choking or coughing while eating or drinking is another red flag. Your vocal cords normally snap shut like a trapdoor when you swallow, keeping food and liquid out of your windpipe. A paralyzed cord can’t close that gap completely, so material slips into the airway. This is called aspiration, and it’s most noticeable with thin liquids. Repeated aspiration can, in rare but serious cases, lead to pneumonia.
How It’s Diagnosed
An ear, nose, and throat specialist will look directly at your vocal cords using a thin, flexible scope passed through the nose or mouth. This allows the doctor to watch whether both cords move normally when you breathe and speak. If one cord sits motionless while the other moves, the diagnosis is straightforward.
For a more detailed view, a test called videostroboscopy uses a small camera combined with a flashing light to record the vocal cords’ vibrations in slow motion. This reveals not just whether a cord moves, but how well it vibrates, how completely the cords close together, and whether the paralyzed cord has lost muscle bulk. Imaging of the neck and chest (CT or MRI) is often ordered to look for tumors or other structural causes along the nerve’s path.
The Waiting Period Before Treatment
Nerves can regenerate, so doctors typically wait at least a year from the onset of paralysis before recommending permanent surgery. During this observation window, a damaged nerve may recover partially or fully on its own, particularly if the cause was viral inflammation or mild surgical stretching rather than a severed nerve. Many patients whose paralysis follows surgery see improvement within the first several months.
This doesn’t mean you wait in silence. Voice therapy and temporary procedures can bridge the gap while you wait to see if the nerve comes back.
Voice Therapy
Voice therapy with a speech-language pathologist is often the first line of treatment and can produce meaningful improvements even without surgery. Sessions typically include breathing control exercises, techniques to reduce strain on the voice box, and exercises that encourage the working vocal cord to compensate by reaching further across the midline.
A 2024 meta-analysis found that voice therapy led to significant improvements across multiple measures: patients reported less voice-related disability, and objective tests showed better vocal stability, reduced breathiness, and longer sustained phonation. Starting therapy early appears to be particularly beneficial. Patients who began non-phonatory exercises soon after diagnosis achieved better vocal cord closure and could sustain sound longer compared to those who delayed treatment. Early therapy also helps prevent the bad vocal habits people naturally develop when trying to force a louder voice from a compromised system.
Surgical Options
If the voice remains inadequate after the observation period, or if the paralysis is clearly permanent, surgery can reposition the paralyzed cord to close the gap.
Injection Laryngoplasty
This is the less invasive option, often used as a temporary measure during the waiting period. A filler material is injected into or beside the paralyzed cord to bulk it up and push it toward the midline. The procedure can be done in an office setting and provides immediate voice improvement, though the effect of temporary fillers wears off over months.
Medialization Laryngoplasty
For a permanent fix, a surgeon makes a small incision in the front of the neck and creates a tiny window in the voice box cartilage. A small implant is placed next to the paralyzed cord, pushing it inward so the working cord can press against it. One unique aspect of this surgery: you’re typically awake. The surgeon asks you to speak during the procedure so the implant can be positioned for the best possible voice. The implant is usually permanent, though it rarely needs repositioning.
One limitation of implants is that they don’t restore muscle tone or the cord’s ability to change tension, so pitch control can feel limited. Over time, the paralyzed cord’s muscles may continue to shrink, which can gradually reduce the benefit.
Nerve Reconnection Surgery
A newer approach called laryngeal reinnervation takes a different philosophy. Instead of propping the cord in place mechanically, a surgeon borrows a nearby working nerve (most commonly one from the neck muscles) and connects it to the damaged nerve supplying the vocal cord. The goal is to restore actual muscle tone and bulk to the paralyzed cord. The operation takes about two hours under general anesthesia, and results develop gradually as the new nerve connection grows in over several months.
A randomized study published in The Laryngoscope compared reinnervation to implant surgery and found both approaches produced clinically meaningful improvements in voice quality and quality of life at 6 and 12 months. Reinnervation patients showed steady gains in how long they could sustain a note, improving from about 5.4 seconds at baseline to 7.8 seconds at one year. Both procedures were considered safe, though reinnervation carries the risks associated with general anesthesia and a longer operation.
Aspiration and Airway Concerns
For most people with unilateral paralysis, the biggest day-to-day frustration is the voice. But aspiration risk deserves attention, especially in older adults or people with other neurological conditions. Thickening liquids, eating slowly, and tucking your chin while swallowing are simple strategies that reduce the chance of liquid entering the airway. Voice therapy exercises that strengthen vocal cord closure also improve swallowing safety.
Bilateral paralysis presents a different challenge entirely. When both cords are stuck near the center, the priority shifts from voice to breathing. Procedures to widen the airway, such as removing a portion of one cord or spreading the cords apart, may be necessary. These procedures improve breathing but often come at the cost of voice quality, creating a tradeoff that requires careful discussion with your surgical team.