New approach to diagnose arytenoid dislocation and subluxation using three-dimensional computed tomography

Using Dynamic CT to Explore the Effect of Disease Course on Arytenoid Dislocation

OBJECTIVE

Using dynamic computed tomography (CT) to explore the structural characteristics of the larynx in patients with arytenoid dislocation and compare the impact of the dislocation course on the structural changes of the larynx.

METHODS

Twenty-three patients with arytenoid dislocation and 10 healthy subjects were selected as the dislocation group and the normal group, respectively. The 23 patients with arytenoid dislocation were divided into groups with dislocation duration less than 3 months (group A) and dislocation duration more than 3 months (group B). Dynamic CT scans were performed on each subjects, and a series of images from inhalation to phonation were collected for three-dimensional reconstruction. The differences in bilateral vocal cord height, area of laryngeal chamber, and glottic gap between the three groups were compared.

RESULTS

There were significant differences in bilateral vocal cord height and area of laryngeal chamber between dislocation group and the normal group. During phonation, the height difference between the bilateral vocal cords in group B was significantly smaller than that in group A. There was a significant difference in the area of the affected laryngeal chamber between groups A and B during inhalation to phonation (P < 0.05). The area of the affected laryngeal chamber in group B was larger than that in group A. There is no significant difference in the glottic gap ratio between the two dislocation groups.

CONCLUSIONS

Dynamic CT can quantitatively evaluate the structural characteristics of the larynx in patients with arytenoid dislocation. As the disease progresses, the structural characteristics of the larynx in patients with arytenoid dislocation will change.

Postnatal changes in thyroid cartilage shape and cartilage matrix composition are not synchronized in Mus musculus

The study was conducted to quantify laryngeal cartilage matrix composition and to investigate its relationship with cartilage shape in a mouse model. A sample of 30 mice (CD-1 mouse, Mus musculus) from five age groups (postnatal Days 2, 21, 90, 365, and 720) were used. Three-dimensional mouse laryngeal thyroid cartilage reconstructions were generated from contrast-enhanced micro-computed tomography (CT) image stacks. Cartilage matrix composition was estimated as Hounsfield units (HU). HU were determined by overlaying 3D reconstructions as masks on micro-CT image stacks and then measuring the attenuation. Cartilage shape was quantified with landmarks placed on the surface of the thyroid cartilage. Shape differences between the five age groups were analyzed using geometric morphometrics and multiparametric analysis of landmarks. The relationship between HU and shape was investigated with correlational analyses. Among five age groups, HU became higher in older animals. The shape of the thyroid cartilage changes with age throughout the entire life of a mouse. The changes in shape were not synchronized with changes in cartilage matrix composition. The thyroid cartilage of young and old M. musculus larynx showed a homogenous mineralization pattern. High-resolution contrast-enhanced micro-CT imaging makes the mouse larynx accessible for analysis of genetic and environmental factors affecting shape and matrix composition.

Hoarseness and arytenoid dislocation: A rare complication after facial bony contouring surgery

BACKGROUND

Arytenoid dislocation is a rare complication after endotracheal intubation and may result in permanent hoarseness, which cannot be tolerated during cosmetic surgeries, such as facial bony contouring surgery. This study aimed to identify the clinical characteristics of this patient subgroup and share the process of diagnosis and treatment.

METHODS

We retrospectively collected the medical records of patients who underwent facial bony contouring surgery under general anesthesia with endotracheal intubation from September 2017 to July 2022. We divided the patients into a nondislocation group and a dislocation group. Demographic, anesthetic, and surgical characteristics were collected and compared.

RESULTS

441 patients were enrolled, and 5 (1.1%) were diagnosed with arytenoid dislocation. The patients in the dislocation group were more likely to be intubated with the video laryngoscope (P = 0.049), and head-neck movement during surgery may predispose patients to arytenoid dislocation (P = 0.019). The patients in the dislocation group were diagnosed around 5-37 days after surgery. Three of them regained their normal voice after close reduction, and two recovered with speech therapy.

CONCLUSION

Arytenoid dislocation may result from multiple factors instead of one high-risk factor. Head-neck movement, the skills and experience of anesthetists, the time of intubation, and the use of intubation tools may all predispose patients to arytenoid dislocation. To acquire timely diagnosis and treatment, patients should be fully informed of this complication before surgery and observed closely afterward. Any postoperative voice or laryngeal symptoms lasting more than 7 days need a specialist evaluation.

To Explore the Changes and Differences of Microstructure of Vocal Fold in Vocal Fold Paralysis and Cricoarytenoid Joint Dislocation by Diffusion Tensor Imaging

OBJECTIVE

The diffusion characteristics of water molecules were measured in the vocal folds of canines exhibiting unilateral vocal fold paralysis and unilateral cricoarytenoid joint dislocation. These characteristics were used in conjunction with a histological examination of the microstructural changes of vocal fold muscle fibers to explore the feasibility of diffusion tensor imaging (DTI) in distinguishing unilateral vocal fold paralysis and unilateral cricoarytenoid joint dislocation as well as evaluating microstructural changes.

METHODS

Ten beagles were randomly divided into three groups: four in the unilateral vocal fold paralysis group, four in the unilateral cricoarytenoid joint dislocation group, and two in the normal group. Unilateral recurrent laryngeal nerve resection was performed in the vocal fold paralysis group. Unilateral cricoarytenoid joint dislocation surgery was performed in the dislocation group. No intervention was performed in the normal group. Four months postintervention, the larynges were excised and put into a magnetic resonance imaging (MRI) system (9.4T BioSpec MRI, Bruker, German) for scanning, followed by an analysis of diffusion parameters among the different groups for statistical significance. After MRI scanning, the vocal folds were cut into sections, stained with hematoxylin and eosin, and scanned digitally. The mean cross-sectional area of muscle fibers, and the mean diameter of muscle fibers in the vocal folds were calculated by target detection and extraction technology. Mean values of each measurement were used to compare the differences among the three groups. Pearson correlation analysis was performed on the DTI parameters and the results from histological section extraction.

RESULTS

The paralysis group had significantly higher Fractional Anisotropy (FA) compared to the dislocation group and normal group (P = 0.004). The paralysis group also had a significantly lower Tensor Trace value compared to the dislocation group and normal group (P = 0.000). The average cross-sectional area of vocal fold muscle fibers in the paralysis group was significantly smaller than the dislocation group and normal group (P = 0.000). Pearson correlation analysis yielded values of, r = -0.785, P = 0.01 between the average cross-sectional area of vocal muscle fibers and FA, and values of r = 0.881, P = 0.00 between Tensor Trace and the average cross-sectional area of vocal muscle.

CONCLUSION

FA and Tensor Trace can be used as effective parameters to reflect the changes of microstructure in vocal fold paralysis and cricoarytenoid joint dislocation. DTI is an objective and quantitative method to effectively evaluate unilateral vocal fold paralysis and unilateral cricoarytenoid joint dislocation, also capable of noninvasively evaluating vocal fold muscle fiber microstructure.

Risk factors of arytenoid dislocation after endotracheal intubation: A propensity-matched analysis

Objective

Arytenoid dislocation (AD) after general anesthesia with endotracheal intubation (EI) is an iatrogenic injury that impairs patient function and requires reduction. We aimed to investigate the risk factors of AD following EI.

Methods

This retrospective case-control study involved surgical adults who received EI for general anesthesia at a single institution from June 2010 to June 2020. Cases included all the patients who had AD. We used a ratio of 1:5 to identify patients in the propensity-matched control group.

Results

Multivariate analysis of 49 cases with AD and 245 controls without AD demonstrated that the use of a nasogastric (NG) tube (odds ratio [OR], 23.9; 95% confidence interval [CI], 6.8-84.1), undergoing abdominal surgery (OR, 3.7; 95% CI, 1.2-11.9), and an operative time longer than 3 h (OR, 5.2; 95% CI, 2.1-12.9) were risk factors for AD. We did not find significant independent associations between AD and 40 years or older age, gender, body mass index, whether a laryngeal mask airway was used, endotracheal tube size, and EI performers' experience.

Conclusion

The use of an NG tube, abdominal surgery, and longer operative time were risk factors for AD. Among these, the NG tube application showed a strong association with AD. Preventive measures of informing the patients of the increased risk and providing high-level patient monitoring can reduce the incidence of AD.

Level of Evidence

III.

Current management of arytenoid sub-luxation and dislocation

PURPOSE

To review the current management of arytenoid subluxation/dislocation (AS/AD) focusing on diagnostic, therapeutic, and prognostic controversies.

METHODS

The international literature of the last 20 years has been considered. After the application of inclusion criteria, 20 studies were selected (471 AS/AD cases in total).

RESULTS

All the included investigations were retrospective case series. AS/AD was often iatrogenic occurring at least in 0.01% of patients undergone endo-tracheal intubation. The most common symptom was persistent hoarseness. The diagnosis was made by video-laryngoscopy and neck computed tomography in most reports, while some used also laryngeal electromyography. Laryngeal electromyography was fundamental to rule out unilateral vocal fold paralysis, the main differential diagnosis. The surgical relocation of AS/AD under general or local anesthesia was achieved in about 80% of patients.

CONCLUSION

AS/AD is a mechanical disorder of the larynx that can be successfully treated if promptly diagnosed. Clinical trials and multi-centric studies are necessary to set management guidelines.

Regularity of voice recovery and arytenoid motion after closed reduction in patients with arytenoid dislocation: a self-controlled clinical study

Background: Closed reduction is an effective treatment for arytenoid dislocation. The treatment is usually given more than once to obtain normal voice. However, when to perform the next closed reduction remains controversial.Objective: This study aimed to observe the regularity of the voice recovery and the arytenoid motion in patients with arytenoid dislocation after closed reduction.Material and methods: Thirty-one patients were recruited from September 2017 to April 2019. Results of their clinical data were reviewed retrospectively.Results: Among the thirty-one patients, their VHI scores, F0, jitter%, shimmer%, glottal-to-noise excitation %(GNE), maximum phonation time (MPT) and GRBAS Scale (G, R, B, A) improved significantly (p < .05), but there was no statistically significant difference for GRBAS Scale (S) (p>.05). The duration between last closed reduction and the restoring normal voice ranged from 1-8 days, with a mean of 4.65 ± 0.57 days, at the same time the glottis was completely closed.Conclusions and significance: Closed reduction for patients with arytenoid dislocation is an effective procedure. A time window between 4.08th and 5.22th day (at a confidence level of 95%) after the last closed reduction was identified to be critical for voice recovery.

Treatment Outcomes of Arytenoid Dislocation by Closed Reduction: A Multidimensional Evaluation

OBJECTIVE

This study aimed to investigate the treatment outcomes of arytenoid dislocation by a multidimensional evaluation.

METHODS

From April 2010 to May 2018, the records of 57 patients with a history of arytenoid dislocation were reviewed. All the patients were treated with closed reduction under local anesthesia. Arytenoid motion, grade, roughness, breathiness, asthenia, strain, maximum phonation time, self-assessed Voice Handicap Index, and acoustic voice analysis were used to evaluate the clinical outcomes.

RESULTS

Following closed reduction, 57 patients were divided into "recovered" (n = 24), "improved" (n = 15), and "ineffective" (n = 18) groups. There were no major complications resulting from surgical intervention.

CONCLUSION

Closed reduction under local anesthesia continues to be an effective and well-tolerated method for treating arytenoid dislocation. The trichotomy of the treatment results of arytenoid dislocation by a multidimensional evaluation may be more accurate to evaluate the results of arytenoid dislocation.

Evaluation of Diffusional Characteristics and Microstructure in Unilateral Vocal Fold Paralysis Using Diffusion Tensor Imaging

OBJECTIVE

To investigate the value of diffusion tensor imaging (DTI) in the evaluation of vocal fold tissue microstructure after recurrent laryngeal nerve (RLN) injury.

METHODS

Six canines were divided into 2 groups: a unilateral vocal fold paralysis group (n = 4) and a control group (n = 2). The RLN was cut in the unilateral vocal fold paralysis group, and no intervention was applied in the control group. After 4 months, the canines' larynges were removed and placed in a small animal magnetic resonance imaging (MRI) system (9.4T BioSpec MRI; Bruker, Germany). After scanning, the vocal folds were isolated, sectioned, and stained. The slides were then analyzed for the cross-sectional area and muscle fiber density through feature extraction technology. Pearson correlation analysis was performed on the DTI scan and histological section extraction results.

RESULTS

In the vocal fold muscle layer, the fractional anisotropy (FA) of the unilateral RLN injury group was higher than that of the control group, and the Tensor Trace was lower than that of the control group. This difference was statistically significant, P < .05. In the lamina propria, the FA of the unilateral RLN injury group was lower than that of the control group, P > .05, and the Tensor Trace was lower than that of the control group, P < .05. The muscle fiber cross-sectional area of the RLN injury group was significantly smaller than the control group with statistical significance, P < .05, and the density of muscle fibers was lower, P < .05. The correlation coefficient between FA and the cross-sectional area was -0.838, P = .002, and .726; P = .017 between Tensor Trace and the cross-sectional area.

CONCLUSION

Diffusion tensor imaging is an effective method to assess the changes in the microstructure of atrophic vocal fold muscle tissue after RLN injury.

A Rare Complication Following Anesthesia: Arytenoid Dislocation During Orthognathic Surgery

PURPOSE

Arytenoid dislocation is a rare complication after tracheal intubation, and there are no published studies reporting on arytenoid dislocation during orthognathic surgery. The frequency of this phenomenon and the results of therapy were evaluated in this study.

MATERIALS AND METHODS

Three of 5,032 patients who underwent orthognathic surgery during an 11-year period had a postoperative arytenoid dislocation. Closed reduction was used in these 3 patients. To check the therapeutic effect, arytenoid dislocation symptoms were recorded and acoustic analysis was performed before reduction, immediately after reduction, and 1, 2, and 4 weeks after reduction.

RESULTS

The incidence of arytenoid dislocation in orthognathic surgery was 0.0596%. The symptoms of 2 patients showed marked improvement 2 weeks after reduction with voice recovery and resolution of odynophagia. The symptoms of the other patient showed marked improvement 4 weeks after reduction. The treatment effects for all 3 patients were satisfactory.

CONCLUSION

Arytenoid dislocation must be considered in cases of prolonged hoarseness after orthognathic surgery. Examination should be carried out as soon as possible, which can hasten the treatment of arytenoid dislocation and achieve a good outcome.

The larynx ruler to measure height and profile of vocal folds: a proof of concept

INTRODUCTION

Glottic leakage during phonation is a direct consequence of unilateral vocal fold (VF) paralysis. This air leakage can be in the horizontal plane and in the vertical plane. Presently, there is no easily applicable medical device allowing noninvasive, office-based measurement of the relative vertical position of the VFs. The larynx ruler (LR) is a laser-based measuring device that could meet the previously stated need, using a flexible endoscope. This study represents a proof of concept regarding the use of the LR in assessing VF relative positions in the vertical plane.

MATERIALS AND METHODS

One fresh male human cadaver larynx, free of neurologic and anatomic disease, was explored with the LR system through the operative channel of a flexible gastroenterology video-endoscope. The tip of the video-endoscope was located in the laryngeal vestibule. The right crico-arytenoid joint was posteriorly disarticulated. Tilting of the VF was obtained by pulling or pushing the arytenoid cartilage with a mosquito forceps fixed to the stump of the previously sectioned superior tip of the posterior crico-arytenoid muscle allowing anterior and posterior tilting of the arytenoid cartilage in order to induce an elevation or a depression of the VF process. Ten "push" and ten "pull" sessions were performed. The distance from the tip of the video-endoscope to each illuminated pixel of the laser beam was recorded. The level difference between the left and right VFs was measured for each recording.

RESULTS

Data provided by the LR were consistently in accordance with the movements applied on the VFs. The accuracy of 0.2 mm of the LR is compatible with the envisioned applications for the human larynx.

CONCLUSION

The LR system represents a feasible technique to evaluate respective vertical position of VFs in the human larynx. Technical limitations were identified that will require improvements before experimental use on human beings.

BMI May Be the Risk Factor for Arytenoid Dislocation Caused by Endotracheal Intubation: A Retrospective Case-Control Study

OBJECTIVE

This study aimed to investigate the risk factors for postoperative arytenoid dislocation caused by endotracheal intubation.

METHODS

From September 2014 to September 2016, the records of 28 patients with a history of postoperative arytenoid dislocation were reviewed. Patients matched in type of anesthesia and surgery were chosen as the control (n = 56). Recorded data for all patients were demographics, smoking status, alcoholic status, operation time, and anesthesia procedures. For arytenoid dislocation cases, we further analyzed the incidences of the left and right arytenoid dislocations. Categorical variables were presented as frequencies and percentages, and were compared using the chi-square test. Continuous variables were expressed as means ± standard deviation and compared using the Student unpaired t test. To determine the predictors of arytenoid dislocation, a logistic regression model was used for multivariate analysis. Statistical significance was indicated by P < 0.05.

RESULTS

Twenty-eight patients demonstrating postoperative arytenoid dislocation (10 women and 18 men) were included, with a mean age of 55 ± 12 years. Sixteen patients (57.14%) had left arytenoid dislocation and 12 (42.86%) had right arytenoid dislocation. Univariate analysis indicated that body mass index (BMI) was associated with arytenoid dislocation (P < 0.01), and logistic regression analysis showed that BMI (P = 0.025) was an independent risk factor for postoperative arytenoid dislocation.

CONCLUSIONS

BMI might be the independent risk factor for postoperative arytenoid dislocation.

The appropriate time for closed reduction using local anesthesia in arytenoid dislocation caused by intubation: a clinical research

CONCLUSION

Closed reduction is effective and safe for the treatment of arytenoid dislocation, and the selection of an appropriate time window to perform closed reduction is crucial in achieving relatively stable treatment outcomes and short treatment duration.

OBJECTIVE

The aim of this study was to investigate whether there is an appropriate time window to perform closed reduction for unilateral arytenoid dislocation caused by intubation.

METHODS

A retrospective chart review was carried out for the cases collected from September 2014 to May 2016 at Second Affiliated Hospital of Zhejiang University, China.

RESULTS

Thirty-five patients with arytenoid dislocation were identified. Endotracheal intubation was the cause for 33 of the patients and gastric tube caused arytenoid dislocation in two patients. The patients were treated by closed reduction, and no major complications resulting from surgical intervention were observed. All patients regained normal voice and vocal fold movement after the surgery, except one patient who recovered spontaneously. As one of the most significant findings in the current study, we observed the relatively stable treatment outcomes and shortened recovery duration were obtained in the patients treated during a period between the 13th day and 26th day after arytenoid dislocation.

Features of Vocal Fold Adductor Paralysis and the Management of Posterior Muscle in Thyroplasty

OBJECTIVE

To present the pathologic characteristics of unilateral recurrent nerve adductor branch paralysis (AdBP), and to investigate the management of posterior cricoarytenoid (PCA) muscle on the basis of our experience of surgical treatment for AdBP.

STUDY DESIGN

This is a retrospective review of clinical records

METHODS

Four cases of AdBP, in which surgical treatment was performed, are presented. AdBP shows disorders of vocal fold adduction because of paralysis of the thyroarytenoid and lateral cricoarytenoid muscles. The PCA muscle, dominated by the recurrent nerve PCA muscle branch, does not show paralysis. Thus, this type of partial recurrent nerve paresis retains the abductive function and is difficult to distinguish from arytenoid cartilage dislocation because of their similar endoscopic findings. The features include acute onset, and all cases were idiopathic etiology. Thyroarytenoid muscle paralysis was determined by electromyography and stroboscopic findings. The adduction and abduction of paralytic arytenoids were evaluated from 3 dimensional computed tomography (3DCT).

RESULTS

In all cases, surgical treatments were arytenoid adduction combined with thyroplasty. When we adducted the arytenoid cartilage during inspiration, strong resistance was observed. In the two cases where we could cut the PCA muscle sufficiently, the maximum phonation time was improved to ≥30 seconds after surgery, from 2 to 3 seconds preoperatively, providing good postoperative voices. In contrast, in the two cases of insufficient resection, the surgical outcomes were poorer.

CONCLUSIONS

Because the preoperative voice in AdBP patients is typically very coarse, surgical treatment is needed, as well as ordinary recurrent nerve paralysis. In our experience, adequate PCA muscle resection might be helpful in surgical treatment of AdBP.

Severe hoarseness associated with the streamlined liner of the pharyngeal airway (SLIPATM)

Hoarseness is a common post-operative complication in patients who receive general anesthesia. In most cases, the symptoms are temporary and improve within several days. This report describes two patients with prolonged hoarseness following use of the streamlined liner of the pharyngeal airway (SLIPATM). We present the first case of a 56-year-old female patient who developed arytenoid cartilage dislocation resulting in prolonged hoarseness and dysphagia after using a SLIPA™ during a laparoscopic myomectomy. In the second case, we report on a 65-year-old male patient who was scheduled for a laparoscopic cholecystectomy. Left vocal fold paralysis or paresis resulting from recurrent laryngeal nerve injury associated with use of a SLIPA™ caused persistent hoarseness. It should be noted that recurrent laryngeal nerve injury or arytenoid cartilage dislocation are possible complications associated with use of the SLIPATM in case of persistent hoarseness.

Arytenoid cartilage dislocation from external blunt laryngeal trauma: evaluation and therapy without laryngeal electromyography

Background

Intubation trauma is the most common cause of arytenoid dislocation. The aim of this study was to investigate the diagnosis and treatment of arytenoid cartilage dislocation from external blunt laryngeal trauma in the absence of laryngeal electromyography (LEMG) and to explore the role of early attempted closed reduction in arytenoids cartilage reposition.

Material/Methods

This 15-year retrospective study recruited 12 patients with suspected arytenoid dislocation from external blunt laryngeal trauma, who were evaluated through 7 approaches: detailed personal history, voice handicap index (VHI) test, indirect laryngoscope, flexible fiberoptic laryngoscope, video strobolaryngoscope, and/or high-resolution computed tomography (CT), and, most importantly, the outcomes after attempted closed reduction under local anesthesia. They were divided into satisfied group (n=9) and dissatisfied group (n=3) based on their satisfied with voice qualities at 1 week after the last closed reduction manipulation.

Results

Each patient was diagnosed with arytenoid dislocation caused by external blunt laryngeal trauma. In the satisfied group, VHI scores and maximum phonation time (MPT) at 1 week after the last reduction were significantly improved compared with those before the procedure (P<0.05). Normal or improved mobility and length of the affected vocal fold were also noted immediately after the end of the last closed reduction. The median time interval between injury and clinical intervention in satisfied group was 43.44±34.13 days, much shorter than the median time of 157.67±76.07 days in the dissatisfied group (P<0.05).

Conclusions

Multimodality assessment protocols are essential for suspected arytenoid dislocation after external blunt laryngeal trauma. Early attempted closed reduction should be widely recommended, especially in health facilities without LEMG, mainly, because it could be helpful for early diagnosis and treatment of this disease. In addition, early closed reduction could also improve the success of arytenoid reduction.

Imaging of laryngeal trauma

External laryngeal trauma is a rare but potentially life-threatening situation in the acutely injured patient. Trauma mechanism and magnitude, maximum focus of the applied force, and patient related factors, such as age and ossification of the laryngeal cartilages influence the spectrum of observed injuries. Their correct diagnosis and prompt management are paramount in order to avoid patient death or long-term impairment of breathing, swallowing and speaking. The current review provides a comprehensive approach to the radiologic interpretation of imaging studies performed in patients with suspected laryngeal injury. It describes the key anatomic structures that are relevant in laryngeal trauma and discusses the clinical role of multidetector computed tomography (MDCT) and magnetic resonance imaging (MRI) in the acute emergency situation. The added value of two-dimensional multiplanar reconstructions (2D MPR), three-dimensional volume rendering (3D VR) and virtual endoscopy (VE) for the non-invasive evaluation of laryngeal injuries and for treatment planning is discussed. The clinical presentation, biomechanics of injury, diagnostic pitfalls and pearls, common and uncommon findings are reviewed with emphasis of fracture patterns, involvement of laryngeal joints, intra- and extralaryngeal soft tissue injuries, and complications seen in the acute emergency situation. The radiologic appearance of common and less common long-term sequelae, as well as treatment options are equally addressed.

Treatment outcomes of closed reduction of arytenoid dislocation

CONCLUSION

Closed reduction is an effective and safe treatment method for arytenoid dislocation. Early closed reduction of arytenoid cartilage plays an important role in voice recovery.

OBJECTIVE

The study reviewed the clinical characteristics of arytenoid dislocation with the aim of identifying factors influencing voice recovery in the closed reduction of arytenoid dislocation.

METHODS

A retrospective chart review was performed at Chonnam National University Hospital for the period from January 2007 to March 2012.

RESULTS

Eleven patients with arytenoid dislocation were identified. The causes of arytenoid dislocation were intubation (n = 9) and blunt trauma (n = 2). All cases of arytenoid dislocations were treated by closed reduction. There were no major complications resulting from surgical intervention. Six of the 11 patients (54.5%) regained normal voice and vocal fold movement after closed reduction. Five patients (45.5%) had significant voice improvement postoperatively. In arytenoid dislocation due to blunt trauma, the duration between injury and voice improvement was much longer than in other causes of arytenoid dislocation (p = 0.012).

Detection of passive movement of the arytenoid cartilage in unilateral vocal-fold paralysis by laryngoscopic observation: useful diagnostic findings

In a previous study of patients with unilateral vocal-fold paralysis (UVFP), three-dimensional computed tomography (3DCT) revealed passive movement during phonation, with the arytenoid cartilage on the paralyzed side pushed to the unaffected side and deviated upwards. The present work compares the 3DCT findings with those obtained by 2-dimensional endoscopy to visualize the vertical passive movement of the arytenoid cartilage. The study population consisted of 23 patients with UVFP and two with laryngeal deviation but normal movement of the vocal folds. Two endoscopic findings represented cranial deviation during phonation: posterior deviation of the arytenoid hump and lateral deviation of the muscular process. These two findings were classified into four grades, ranging from 0 (normal) to 3 (severe). Cranial displacement detected by 3DCT was also classified into four grades. Significant correlations were found between the 3DCT-determined grade of cranial displacement of the arytenoid cartilage and the grade assigned based on the two endoscopic findings. Moreover, lateral deviation of the muscular process was more significantly correlated with 3DCT grade than with endoscopic grade. Thus, endoscopic findings may be useful in the diagnosis of vocal-fold paralysis, and passive lateral deviation of the muscular process as an indicator of UVFP.