Dislocation or subluxation of the cricoarytenoid joint is mainly caused by tracheal intubation injury and neck trauma, which is rarely reported in the general literature. However, in recent years, as the proportion of general anesthesia intubation increases year by year and tracheal intubation techniques become more and more popular, there is a tendency to increase the incidence of this injury among unskilled operators. The consequences of this kind of laryngeal injury can cause postoperative vocal function and swallowing dysfunction, and this complication has a certain incidence, so it should be paid great attention.
1.Types of cricoarytenoid dislocation
According to the left and right anatomical position of the arytenoid cartilage, it can be divided into: left and right dislocation of the cricoarytenoid joint;
According to the direction of dislocation, it can be divided into: anterior and posterior dislocation of the cricoarytenoid joint;
According to the degree of dislocation, it can be divided into: total dislocation and subluxation of the crico-arytenoid joint.
Among them, left anterior subluxation is the most common, because the general operation in the larynx is that the operator holds the instrument (laryngoscope, etc.) in the left hand and advances the tracheal tube and gastric tube in the right hand.
2. Causes of cricoarytenoid joint
Patient factors.
(1) Short and thick neck, difficulty in exposing the vocal cords, and poor visual field;
(2) Old age, frailty, prolonged illness, and hypotonia;
(3) Disease causing degenerative changes in the ligaments of the cricoarytenoid joint;
(4) Invasion of laryngeal tumor, systemic diseases including chronic renal failure (especially renal failure due to diabetes mellitus), ulcerative colitis, laryngeal tenderness, acromegaly, and long-term glucocorticoid use patients are prone to cricoarytenoid joint dislocation due to degeneration of the cricoarytenoid joint and weakening of its ligament tension.
Operative factors.
Anterior dislocation of the left arytenoid cartilage is more frequent because the operator holds the laryngoscope in the left hand and the catheter is inserted into the laryngeal cavity from the right side;
Anterior dislocation.
① The lens is placed too deep;
(ii) The laryngoscope reveals the vocal fissure, and the lens pulls the epiglottis with excessive tension, colliding with the arytenoid cartilage;
(3) The tip of the catheter or the core directly hits the arytenoid cartilage when seeking the vocal fissure.
Posterior dislocation is related to the distal bend of the catheter squeezing the arytenoid cartilage posteriorly during anesthesia.
It is related to the anesthesiologist’s lack of operational experience and unskilled technique!
The timing of intubation is not good; when intubating a critically ill patient, the patient is in a hurry and moves roughly;
Intubation of awake patients, too fast action, forced intubation when laryngeal reflex is obvious;
Intubation errors and assistant pressure on the chest or larynx;
Improper use of the core;
Insufficient induction of anesthesia for tracheal intubation, which causes the patient to swallow and choke too often, resulting in upward and downward pulling of the larynx, which can easily cause dislocation of the arytenoid cartilage. When the tracheal intubation is removed, the arytenoid cartilage is displaced posteriorly and externally due to insufficient deflation of the balloon and forced removal of the balloon when it is still partially filled.
Both intubation and extubation may cause dislocation!
Invasive operations.
(1) Placement and retention of gastric tube
Multiple placement of gastric tube with hard texture and coiling of gastric tube at the acoustic opening, which pulls the arytenoid cartilage causes.
If the gastric tube is located in the middle position for a long time, the posterior lateral branch of the recurrent laryngeal nerve is compressed or the muscle is spasmed, which may lead to ulcer formation, infection, and vocal fold dysfunction in the arytenoid cartilage part and posterior cricoid cartilage.
(2)Gastroscopy placement
(3)TEE ultrasound probe placement
3.Diagnosis of cricoarytenoid dislocation
Dislocation of the cricoarytenoid joint should be detected early and treated promptly. The symptoms of cricoarytenoid dislocation are mainly hoarseness, laryngeal pain, painful swallowing, choking and coughing when eating. Among them, hoarseness is the most dominant clinical manifestation, and an auditory analysis score has been proposed. Accordingly, the degree of dislocation and injury is assessed by the RBH scale: Roughness, Breathiness and Hoarseness.
CT examination, branched fiberscopy, direct laryngoscopy, bronchoscopy, and esophagoscopy are all used to diagnose cricoarytenoid dislocation. A fine scan (1 mm) is considered appropriate for CT examination. Television laryngoscopy is the most useful method. The treatment effect of cricoarytenoid dislocation is closely related to the time of consultation, and early treatment is crucial to the prognosis. If it enters the chronic stage after the joint fibrosis, the activity is impaired and the vocal cord is fixed and then the treatment is not ideal.
4.Treatment of dislocation of cricoarytenoid joint
Closed repositioning of the cricoarytenoid joint, i.e., arytenoid cartilage pivot.
Timing: Generally, it is performed within 24-48h after the occurrence of dislocation with good results, and the timing is flexible depending on the patient’s condition on the premise that the earlier the better.
Effect: It depends on the experience of the surgeon and the length of time after dislocation of the patient, and generally requires 2 to 3 times and close cooperation of the patient.
Toggle tight reset under local anesthesia
For posterior-lateral dislocation, place the repositioner at the bottom of the affected pear-shaped fossa and pivot the arytenoid cartilage forward and inward in accordance with the trajectory of the cricoid arytenoid node;
For anteromedial dislocation, the repositioner is gently placed anteromedially to the affected arytenoid cartilage, and the arytenoid cartilage is plucked posteriorly and laterally while the patient is vocalizing.
If the vocalization is good or significantly improved from the preoperative level;
If the affected side of the phial is symmetrical to the opposite side and the vocal fold movement is restored, then the pivoting repositioning is considered successful; otherwise, the position is appropriately adjusted and pivoted again.
Generally, one local anesthesia can be performed 1-5 times.
Reset under general anesthesia to support the laryngoscope to expose the phial fissure and vocal folds.
After determining the dislocation of the arytenoid cartilage, pivot repositioning is performed along its trajectory, and the position of the phial is observed to determine the repositioning of the arytenoid cartilage after each pivot operation.
Adjust the depth of anesthesia, observe the movement of the vocal cord, and evaluate the efficacy.
If the repositioning is not satisfactory, adjust the toggle technique immediately and toggle repositioning again.
Botulinum toxin injection to selectively support the specific laryngeal muscles of the arytenoid cartilage and correct the arytenoid cartilage repositioning to normal position.
Only for anterior and middle arytenoid cartilage dislocation;
In order to balance the laryngeal muscle forces, it is important to prevent injection through the myofascia into other muscles;
Botulinum toxin 75 U is injected into the repositioned lateral arytenoid and lateral cricothyroid muscles after manipulation;
Teflon is injected to fix the cricoarytenoid joint while keeping the vocal folds on one side in neutral position.
Surgical treatment is used only if tight repositioning fails or if surgical treatment is deemed necessary after examination of the cricoarytenoid cartilage. Open repositioning, such as arytenoid cartilage inversion or rotation, or even arytenoid cartilage resection.
Vocal cord restoration therapy. In some patients, the dislocated cricoarytenoid joint can be reset automatically after appropriate training, or most of its functions can be restored to normal after compensating for the contralateral vocal cord.
Anti-inflammatory drugs, such as steroid hormones or non-steroidal steroids, can be used as an adjunct to treatment.
5.Prevention of cricoarytenoid dislocation
Familiar with the anatomical structure of the larynx, familiar with the operation process, and skilled in dealing with various unexpected situations;
Choose a suitable tracheal tube, use lubricant outside the tube to reduce resistance friction, and fully deflate the balloon when tracheal extubation;
Complete anesthesia, accurate judgment of intubation timing, avoid choking and swallowing, and reduce laryngeal muscle tension during intubation;
The operation of formal tracheal intubation should be steady, accurate, light and fast. Avoid using violence and inappropriate wicks, and do not insert the laryngoscope too deeply;
Pay attention to the appropriate adjustment of the patient’s body position at the right time; avoid excessive posterior tilt;
Do not apply inappropriate pressure outside the larynx.
Choose a soft gastric tube of moderate thickness and cooperate closely with the patient during insertion.
Patients with diabetes mellitus, chronic colitis, acromegaly, or long-term application of steroid hormone drugs should have a detailed medical history.
For patients with difficult tracheal intubation process, close postoperative follow-up should be performed to detect the dislocation of the cricoarytenoid joint in time for early treatment.
In cases of scar contracture and anterior flexion deformity of the neck with poor vocal portal exposure, repeated intubation should be avoided, and intubation under fiberoptic bronchoscopic guidance is feasible when necessary.