What is Arytenoid Subluxation?
Arytenoid subluxation is a condition where the arytenoid cartilage, a small, pyramid-shaped part of your throat, moves out of its normal place. It’s a rare issue that normally happens after an injury that happens during procedures involving the throat, such as laryngoscopy and intubation, or from trauma to the throat.
The arytenoids are a pair of small cartilages in your throat that connect with the cricoid cartilage. They, along with the cricoarytenoid joints, can be quite delicate and prone to damage during throat procedures. It’s common for medical staff to see a bulge in the tissue that covers the arytenoids during a laryngoscopy.
The arytenoids have a peak, a base, and two extensions (for voice and muscles). The vocal extensions go forward and connect to the vocal ligament, controlling the tightness, looseness, or approximation of the vocal folds. The muscular extensions provide a point of attachment for the muscles that control the opening and closing of the glottis, which is how the vocal cords move. It also supports the top part of the arytenoids and their interaction with the cricoid cartilage. The cricoarytenoid joint is crucial in controlling the movement of the vocal cords, needed for breathing, speaking, and protecting the airway.
Often, you might see the terms ‘subluxation’, and ‘dislocation’ used to describe the same thing. However, a dislocation means the arytenoid cartilage is completely separated from the joint, while a subluxation means it’s only partially displaced. Both conditions are considered variations of the same problem with different levels of severity, affecting us in the same way. A subluxation can be classified as anterior when the displacement is towards the front, or posterior when the displacement is towards the back.
What Causes Arytenoid Subluxation?
Arytenoid subluxation, or dislocation of the arytenoid cartilages in the voice box, usually happens after a traumatic event that affects the area where the arytenoid and cricoid cartilages meet. It can be due to several factors, including the improper insertion of a breathing tube, difficulty placing the tube in the airway causing damage or prolonged procedure, use of a gum elastic bougie (a device to insert the tube), blind intubation methods (like using a lighted instrument), or inserting bulky tubes with two lumens.
Other related factors can be the skill level of the person performing the procedure, a bad dental bite, having a small jaw or a large tongue. Also, instances of severe coughing or even spontaneous dislocation of the arytenoid have been reported.
Some systemic diseases, chronic use of corticosteroids, conditions causing softening of the larynx or growth hormone disorders could weaken the joint’s protective layer, making this complication worse. Being overweight might also increase the risk. Major heart surgeries that require the use of a probe for ultrasound imaging of the esophagus may also increase the chance of this happening. The likely cause in these cases is the placement of the probe itself.
Risk Factors and Frequency for Arytenoid Subluxation
The chance of having arytenoid subluxation, which is a condition that can occur after a medical procedure called endotracheal intubation, is currently reported to be quite low – between 0.01% and 0.1%. However, some believe the true number could be higher. For example, Rudert and his team suggested that as many as 30% of patients who experienced prolonged hoarseness after their larynx was worked on might have this condition, with around 80% to 90% of these cases being due to trauma from intubation.
It’s also worth noting that while arytenoid subluxation or dislocation usually occurs in adults, it can also affect children and even newborn babies.
Signs and Symptoms of Arytenoid Subluxation
People with tracheal injuries often have a raspy or rough voice, trouble swallowing, and neck pain. These symptoms usually occur after a traumatic procedure that involves placing a tube down their windpipe (intubation) or some sort of procedure that involves the upper airway. There have been rare reports of a severe cough, external blunt trauma, or even spontaneous events leading to these symptoms. Respiratory issues that can develop include difficulty breathing and symptoms that mimic asthma.
Doctors must initially make sure the patient is not dealing with life-threatening conditions like stridor (a noisy or high-pitched sound with breathing), difficulty breathing, and blood clots within the neck or on its surface. Diagnostic procedures such as flexible fiber-optic laryngoscopy and videostroboscopy are used to give a direct and dynamic view of the structures in the voice box.
Testing for Arytenoid Subluxation
There’s no single perfect method for diagnosing potential damage after a procedure involving a breathing tube. If someone experiences a change in their voice after the tube is removed, several examinations are necessary to understand what might have happened.
Firstly, a flexible fiberoptic laryngeal examination allows doctors to observe any unusual placement or movements of the vocal fold (the part of our throat that produces sound) and a small piece of cartilage involved in opening and closing the vocal folds, called the arytenoid cartilage. The examination can also detect any damage to the larynx (the part of the throat involving the vocal folds).
Videostroboscopy uses a strobe light to capture detailed video of the throat during sound production, which can show if there are differences in length between the vocal cords, or if the arytenoid cartilages are at uneven heights.
Computed tomography, or CT scans, can show whether the vocal cords are unevenly placed. This is a common sign of arytenoid cartilage dislocation, where this piece of cartilage moves out of place. However, for younger patients where the cartilage may not be fully hardened, it might not be as useful.
A laryngeal electromyography test, which measures the electrical activity of the muscles in the throat, can help differentiate between a dislocated arytenoid cartilage and vocal cord palsy. For the former, the result of the test would usually be normal, while for the latter, the result would typically show an issue. But, both dislocation and a blood-filled swelling (hematoma) can occur with certain conditions, which can make diagnosis complicated.
The most accurate way to diagnose this issue seems to be by using a combination of the patient’s history and physical signs, the flexible fiberoptic laryngoscopy, a laryngeal CT scan, and an electromyography test.
Treatment Options for Arytenoid Subluxation
The typical treatment for a certain vocal cord condition is a procedure called closed arytenoid reduction, done through a process known as direct laryngoscopy. During this procedure, a part of the vocal cord called the arytenoid cartilage is moved to sit on top of another part called the cricoid. The idea is to position it as evenly as possible compared to the arytenoid cartilage on the other side. This process is generally done under sedation, and the patient’s voice quality is monitored during the procedure itself. If the voice improves right away, it’s a good sign that the diagnosis was correct. However, if the patient also has a nerve injury, they may experience delayed improvement, or no improvement at all.
If the diagnosis takes too long, scar tissue can form, which makes the treatment harder. In these cases, open procedures like thyroplasty and arytenoidopexy may need to be considered. Other treatment methods can be used to compliment these procedures, such as botulinum toxin and voice therapy.
Certain patients who can’t undergo surgery for various reasons could opt for vocal cord augmentation procedures. During these procedures, temporary materials like absorbable gelatin powder, or more permanent ones like a substance known as polytetrafluoroethylene paste, are injected into the vocal cord. This can improve the patient’s voice quality and reduce the risk of choking or aspirating.
Simply managing the condition through voice therapy can also yield good results. In voice therapy, patients typically learn voice exercises, relaxation techniques for the vocal cords and mechanisms to compensate for any voice issues they might have.
What else can Arytenoid Subluxation be?
The primary condition to consider when diagnosing voice box paralysis could be a paralyzed recurrent laryngeal nerve. A specific diagnostic test known as laryngeal electromyography helps distinguish between arytenoid subluxation and paralysis of this nerve. This test might also provide some hints about the possibility of recovering from vocal fold paralysis.
However, it’s important to note that this test isn’t always perfect as temporary muscle weakness could occur with either a displacement of the vocal cords (called subluxation) or a blood clot (known as hematoma).
What to expect with Arytenoid Subluxation
About 19% of patients experience a spontaneous reduction and get better without treatment. Results are usually better when treatment is provided early. In fact, almost all patients regain their normal voice and vocal cord function immediately after a procedure known as closed reduction.
Good voice recovery can also be achieved even if the treatment is delayed. Patients who do not show improvement immediately often have an associated nerve injury. However, in some cases, these patients may recover over time. If the condition is left untreated for too long, the joint in the larynx (arytenoid joint) can become stiff and get stuck in an uncomfortable position.
Possible Complications When Diagnosed with Arytenoid Subluxation
If the condition lasts for a long time, patients may experience a stiffening and scarring of the cricoarytenoid (a joint in the voice box), leading to constant hoarseness, difficulty in swallowing, and even breathing problems.
Recovery from Arytenoid Subluxation
Voice therapy can be useful after surgery, or it can act as a beneficial and successful treatment by itself. This is a good option for patients who would rather go for non-invasive treatments.
Preventing Arytenoid Subluxation
It’s essential that patients receiving a procedure called endotracheal intubation be informed about any potential side effects. Patients should be advised to look out for symptoms like continuous harshness in voice or difficulty swallowing, which might develop suddenly. If these symptoms occur, seek immediate help from a healthcare provider.
