New insights into the pathomechanism of postintubation arytenoid subluxation

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.

Head-neck movement may predispose to the development of arytenoid dislocation in the intubated patient: a 5-year retrospective single-center study

Background

Arytenoid dislocation is a rare laryngeal injury that may follow endotracheal intubation. We aimed to determine the incidence and risk factors for arytenoid dislocation after surgery under general anaesthesia.

Methods

We reviewed the medical records of patients who underwent operation under general anaesthesia with endotracheal intubation from January 2014 to December 2018. Patients were divided into the non-dislocation and dislocation groups depending on the presence or absence of arytenoid dislocation. Patient, anaesthetic, and surgical factors associated with arytenoid dislocation were determined using Poisson regression analysis.

Results

Among the 25,538 patients enrolled, 33 (0.13%) had arytenoid dislocation, with higher incidence after anterior neck and brain surgery. Patients in the dislocation group were younger (52.6 ± 14.4 vs 58.2 ± 14.2 yrs, P = 0.025), more likely to be female (78.8 vs 56.5%, P = 0.014), and more likely to be intubated by a first-year anaesthesia resident (33.3 vs 18.5%, P = 0.048) compared to those in the non-dislocation group. Patient positions during surgery were significantly different between the groups (P = 0.000). Multivariable Poisson regression identified head-neck positioning (incidence rate ratio [IRR], 3.10; 95% confidence interval [CI], 1.50–6.25, P = 0.002), endotracheal intubation by a first-year anaesthesia resident (IRR, 2.30; 95% CI, 1.07–4.64, P = 0.024), and female (IRR, 3.05; 95% CI, 1.38–7.73, P = 0.010) as risk factors for arytenoid dislocation.

Conclusion

This study showed that the incidence of arytenoid dislocation was 0.13%, and that head-neck positioning during surgery, less anaesthetist experience, and female were significantly associated with arytenoid dislocation in patients who underwent surgeries under general anaesthesia with endotracheal intubation.

Tracheal tube size in adults undergoing elective surgery - a narrative review

Tracheal tubes are routinely used in adults undergoing elective surgery. The size of the tracheal tube, defined by its internal diameter, is often generically selected according to sex, with 7-7.5 mm and 8-8.5 mm tubes recommended in women and men, respectively. Tracheal diameter in adults is highly variable, being narrowest at the subglottis, and is affected by height and sex. The outer diameter of routinely used tracheal tubes may exceed these dimensions, traumatise the airway and increase the risk of postoperative sore throat and hoarseness. These complications disproportionately affect women and may be mitigated by using smaller tracheal tubes (6-6.5 mm). Patient safety concerns about using small tracheal tubes are based on critical care populations undergoing prolonged periods of tracheal intubation and not patients undergoing elective surgery. The internal diameter of the tube corresponds to its clinical utility. Tracheal tubes as small as 6.0 mm will accommodate routinely used intubation aids, suction devices and slim-line fibreoptic bronchoscopes. Positive pressure ventilation may be performed without increasing the risk of ventilator-induced lung injury or air trapping, even when high minute volumes are required. There is also no demonstrable increased risk of aspiration or cuff pressure damage when using smaller tracheal tubes. Small tracheal tubes may not be safe in all patients, such as those with high secretion loads and airflow limitation. A balanced view of risks and benefits should be taken appropriate to the clinical context, to select the smallest tracheal tube that permits safe peri-operative management.

Clinical characteristics of arytenoid dislocation in patients undergoing bariatric/metabolic surgery: A STROBE-complaint retrospective study

Tracheal intubation and the use of a large-bore calibrating orogastric (OG) tube have been reported to increase the incidence of arytenoid dislocation (AD) in patients undergoing bariatric/metabolic surgery. This study aimed at identifying the clinical characteristics of this patient subgroup.We retrospectively examined the clinical characteristics of 14 patients with AD (study group) who received tracheal intubation and OG insertion for bariatric/metabolic surgery between 2011 and 2016. For comparison, another group of 19 patients with postoperative AD collected from published literature and 3 patients from the authors' institute served as controls in whom only tracheal intubation was performed. Information on patient characteristics, anesthetic time, symptoms, time of symptom onset, intervention, and postinterventional impact on vocalization of the 2 groups were collected and compared.Patients in the study group were younger than those in the control group (38 [25-60] vs 54.5 [19-88] years, P = .03). Compared with the control group, anesthetic time (282.5 [155-360] vs 225 [25-480] minutes, P = .041) was longer and symptom onset (1.0 [0-6] vs 1.0 [0-6] days, P = .018) was more delayed in the study group. After closed reduction, the frequency of voice recovery was comparable in both groups in a time interval of 12 weeks (84.6% vs 92.9%, P = .59).Our report demonstrates that the clinical characteristics of patients with AD who received tracheal intubation and OG insertion for bariatric/metabolic surgery were different from those with postoperative AD receiving only tracheal intubation, highlighting the importance of implementing individualized strategies for AD prevention in this patient population.

Arytenoid cartilage dislocation mimicking bilateral vocal cord paralysis: A case report

RATIONALE

Arytenoid dislocation is very rare and may be misdiagnosed as vocal cord paralysis or a self-limiting sore throat.

PATIENT CONCERNS

A 70-year-old male (70 kg, 156 cm) was scheduled for transurethral resection of bladder tumors. A McGrath videolaryngoscope, with a basic cuffed Mallinckrodt oral tracheal tube of 7.5 mm internal diameter, was used to successfully intubate his trachea. The duration of surgery was 25 minutes. In the recovery room, he complained of sore throat and dyspnea with inspiratory stridor, which were not resolved after intravenous injection of 10 mg of dexamethasone.

DIAGNOSES

The otolaryngological examination revealed midline fixation of the bilateral vocal folds, suggestive of bilateral arytenoid dislocation or bilateral vocal cord palsy. The latter was ruled out because there was no evidence of recurrent laryngeal nerve injury.

INTERVENTIONS

Under general anesthesia, a closed reduction was performed using laryngoscopic forceps to apply posterolateral pressure on the arytenoid joints on both sides. Only the dislocation of the left cricoarytenoid joint could be easily reduced, whereas reduction of the right joint was not possible.

OUTCOMES

On postoperative day 7, examination with a rigid laryngoscope showed a medially fixed right vocal fold, with full compensation by the left vocal fold. Computed tomography of the neck showed no pathologic findings. Six weeks after surgery, the patient had regained his normal voice with no complications.

LESSONS

Although arytenoid dislocation is a rare complication, it should be considered even in patients with uncomplicated tracheal intubation. Early diagnosis and the optimal therapeutic approach are critical for restoration of the patient's original vocal cord function.

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.

Correlation between extraction force during tracheal intubation stylet removal and postoperative sore throat

STUDY OBJECTIVE

To examine postoperative sore throat resulting from tracheal intubation stylet removal.

DESIGN

Prospective cohort study.

SETTING

Operating rooms and hospital ward.

PATIENTS

A total of 50 American Society of Anesthesiologists physical status 1 and 2 patients who underwent elective abdominal and/or orthopedic surgery under general anesthesia.

INTERVENTIONS

Patients were allocated to 2 groups: those who developed sore throat postoperatively (ST group) and those who did not (NST group). Comparative analysis of these 2 groups was performed to identify risk factors of the development of sore throat.

MEASUREMENTS

The extraction force during stylet removal was measured using a force measuring device. Postoperative sore throat was assessed by an anesthesiologist.

MAIN RESULTS

Nine patients (18%) complained of postoperative sore throat. Increased extraction force (P=.0054; odds ratio, 1.84; 95% confidence interval, 1.20-2.84) was the only significant risk factor for the development of postoperative sore throat. An extraction force of >10.3N was determined as a cutoff for developing postoperative sore throat.

CONCLUSION

Postoperative sore throat was significantly related to increased extraction force during stylet removal.

Nomenclature proposal to describe vocal fold motion impairment

The terms used to describe vocal fold motion impairment are confusing and not standardized. This results in a failure to communicate accurately and to major limitations of interpreting research studies involving vocal fold impairment. We propose standard nomenclature for reporting vocal fold impairment. Overarching terms of vocal fold immobility and hypomobility are rigorously defined. This includes assessment techniques and inclusion and exclusion criteria for determining vocal fold immobility and hypomobility. In addition, criteria for use of the following terms have been outlined in detail: vocal fold paralysis, vocal fold paresis, vocal fold immobility/hypomobility associated with mechanical impairment of the crico-arytenoid joint and vocal fold immobility/hypomobility related to laryngeal malignant disease. This represents the first rigorously defined vocal fold motion impairment nomenclature system. This provides detailed definitions to the terms vocal fold paralysis and vocal fold paresis.

Hoarseness after thyroidectomy: blame the endocrine surgeon alone?

OBJECTIVE

Hoarseness is a postoperative complication of thyroidectomy, mostly due to damage to the recurrent laryngeal nerve (RLN). Hoarseness may also be brought about via vocal cord dysfunction (VCD) due to injury of the vocal cords from manipulations during anesthesia, as well as from psychogenic disorders and respiratory and upper-GI related infections. We reviewed the literature aiming to explore these potential surgical and non-surgical causes of hoarseness beyond thyroidectomy and the role of the endocrine surgeon. Is he/she alone to blame?

METHODS/MATERIAL

The MEDLINE/PubMed database was searched for publications with the medical subject heading "hoarseness" and keywords "thyroidectomy", "RLN", "VCD" or "intubation". We restricted our search till up to May 2013.

RESULTS

In our final review we included 80 articles and abstracts that were accessible and available in English. We demonstrated the incidence of hoarseness stemming from surgical and non-surgical causes and also highlighted the role of intubation as a potential cause of injury-related VCD.

CONCLUSIONS

Hoarseness is a relatively common complication of thyroidectomy, which can be attributed to many factors including surgeon's error or injuries during intubation as well as to other non-surgical causes. However, compared to procedures such as cervical spine surgery, mediastinal surgery, esophagectomy and endarterectomy, thyroidectomy would seem to be a procedure with a relatively low rate of recurrent laryngeal nerve palsies (RLNPs). It is often difficult to determine whether the degree of hoarseness after thyroidectomy should be attributed only the surgical procedure itself or to other causes, for example intubation and extubation maneuvers. The differential diagnosis of postoperative hoarseness requires the use of specific tools, such as stroboscopy and intra- and extralaryngeal electromyography, while methods like acoustic voice analysis, with estimation of maximum phonation time and phonation frequency range, can distinguish between objective and subjective deterioration in the voice. The importance of medical history should be also emphasized.

High-force simulated intubation fails to dislocate cricoarytenoid joint in ex vivo human larynges

OBJECTIVES

We assessed the likelihood of arytenoid dislocation during intubation through the application of controlled force.

METHODS

Six cadaveric human larynges were mounted in an apparatus for simulating forcible collision with the arytenoid complexes. An endotracheal tube tip probe (ETTP) was used to push one arytenoid complex, and a non-slip probe (NSP) was tested on the other. Increasing pressure was applied until the probes either slipped or reached 5 kg of force. Dissection was then performed to assess the integrity of the cricoarytenoid ligament. The forces obtained by pushing an endotracheal tube against an electronic balance were measured to estimate the maximal possible intubating force.

RESULTS

None of the ETTP or NSP trials disrupted the cricoarytenoid joint ligaments, and the joint never appeared to be dislocated. The mean maximal forces were 1.8 kg for the ETTP (after which, slippage consistently occurred) and 4.7 kg for the NSP. The mean maximal forces from an endotracheal tube pushed against a scale were 1.5 kg (without stylet) and 4.6 kg (with stylet).

CONCLUSIONS

Arytenoid dislocation did not happen, and gross disruption of the joint capsule or ligament did not occur, even when the testing approximated the maximum force achievable under extreme conditions. Endotracheal tube insertion thus seems unlikely to cause arytenoid dislocation.

Characteristics of Vocal Fold Immobility following Endotracheal Intubation

Objectives:

We investigated the clinical and laryngeal electromyography (LEMG) characteristics and the outcome of closed reduction of arytenoid cartilage dislocation in patients with vocal fold immobility (VFI) following endotracheal intubation.

Methods:

Sixty patients with VFI following endotracheal intubation were included. Closed reduction was performed under local anesthesia in 54 cases. Another 6 patients did not undergo an intervention. Laryngeal behaviors and voice function were evaluated. Forty-five patients underwent LEMG testing.

Results:

All patients complained of persistent hoarseness immediately following surgery. The LEMG results for 29 of 45 patients showed normal patterns (15 cases) or mildly abnormal patterns (14 cases) on the affected side. Sixteen cases displayed apparent abnormal LEMG patterns on the affected side. The voices of all 54 patients improved after reduction. The movement of the affected vocal folds recovered to normal in 51 cases. One month after reduction, neuromuscular function had improved in 29 of 30 cases. Among the 6 patients who did not undergo intervention, 3 had normal or slightly hoarse voices, and 3 experienced moderate hoarseness.

Conclusions:

Vocal fold immobility following endotracheal intubation is typically caused by arytenoid dislocation. Some instances were accompanied by an abnormality of the recurrent laryngeal nerve. A timely closed arytenoid reduction should be performed to restore patients' normal voices and vocal fold mobility. Our reduction technique under local anesthesia can be performed easily and obtains satisfactory outcomes within 6 weeks after endotracheal intubation.

A promising new technique for closed reduction of arytenoid dislocation

Objectives:

To study the effect of a new technique for closed reduction of dislocated arytenoids.

Methods:

The study included 21 females (72.4 per cent) and eight males (27.6 per cent) with a diagnosis of arytenoid dislocation. There were 18 cases of left arytenoid dislocation and 11 of right arytenoid dislocation.Twenty-eight cases had anteromedial dislocation and one had posterolateral dislocation. All patients were treated with closed reduction using custom-made metal rods and an operating microscope, under general anaesthesia.

Results:

Post-operatively, 21 patients’ voices returned completely to normal (including full vocal fold mobility), five had an improved voice and three failed to show any improvement. There were no post-operative complications.

Conclusion:

This new closed reduction technique is a safe procedure for patients with dislocated arytenoids. It is repeatable and the outcome is reliable and effective. Closed reduction can be a useful treatment for arytenoid dislocation.

Arytenoid dislocation: An analysis of the contemporary literature

OBJECTIVES/HYPOTHESIS

To discuss the incidence, diagnosis, laryngeal findings, and management of arytenoid dislocation as a separate entity from vocal fold paralysis.

STUDY DESIGN

Literature review.

METHODS

A contemporary review of the literature was performed by searching the terms arytenoid cartilage dislocation and subluxation in various combinations. Articles were analyzed and selected based on relevance and content.

RESULTS

Arytenoid dislocation is described as an uncommon laryngeal finding associated with intubation or blunt laryngeal trauma. The majority of recent publications are case reports or small case series. Diagnosis of arytenoid dislocation with flexible laryngoscopy, helical computed tomography, videostroboscopy, and laryngeal electromyography is recommended. In most reported cases, diagnosis has been made based on the position of the arytenoid at laryngoscopy. Reduction and repositioning of the arytenoid cartilage is reported with limited success noted with delayed diagnosis. Speech therapy may also be a beneficial treatment option.

CONCLUSIONS

Although arytenoid dislocation is reported in the literature, the body of available evidence fails to sufficiently differentiate it as a separate entity from unilateral vocal fold paralysis. Flexible laryngoscopy is inadequate as a standalone procedure to distinguish arytenoid dislocation from laryngeal nerve injury.

Arytenoid dislocation related to an uneventful endotracheal intubation: a case report

INTRODUCTION

Invasive methods currently applied to the respiratory tract may result in impaired movement of the cricoarytenoid joint with hoarseness and immobility of the vocal ligament. Hoarseness after tracheal intubation is reported as a high incidence in patients who receive general anaesthesia. In most cases, the symptoms are temporary and improve within several days. We report this case for emphasizing that early diagnosis of arytenoid cartilage dislocation is important even in nontraumatic cases.

CASE PRESENTATION

We present the case of a 19-year-old Caucasian male who developed arytenoid cartilage dislocation associated with uneventful endotracheal intubation and anesthesia.

CONCLUSION

Arytenoid subluxation should be considered whenever any of the symptoms mentioned occur following endolaryngeal manipulation, and they become persistent, as recovery becomes difficult if appropriate treatment is not started immediately.

[Laryngopharyngeal morbidity following general anaesthesia. Anaesthesiological and laryngological aspects]

Laryngeal and pharyngeal complaints are among the subjective problems most frequently reported by patients after general anaesthesia involving endotracheal intubation, others being pain, nausea and vomiting. Hoarseness, sore throat, and vocal cord injuries restrict patients' social lives, and in some cases also their working lives. The most frequent types of laryngeal injury are swollen mucosa and haematoma of the vocal cords. Vocal cord paralysis occurs much less frequently. Knowledge of the pathophysiological aspects and other relevant factors associated with laryngopharyngeal morbidity are essential cornerstones of quality assurance in perioperative respiratory tract management. In this review specific sections are devoted to the implications of anaesthesia involving endotracheal intubation and laryngeal masks for laryngopharyngeal morbidity, and also particular aspects of thyroid gland surgery, cardiothoracic and bariatric surgery and obstetric and paediatric anaesthesia, and medicolegal aspects.

Update Larynx: funktionelle Anatomie unter klinischen Gesichtspunkten

ENT specialist and phoniatricians are not the only professionals for whom diseases of the larynx occupy centre stage; this applies to those in all fields involving conservative or surgical treatment of the larynx, such as speech therapists, paediatricians, anaesthetists, oncologists, pulmonologists, radiologists and general practitioners. On the basis of current knowledge and taking account of results yielded by their own research in recent years and of clinical aspects, in this paper the authors give a short overview of basic knowledge on the anatomy and physiology of the larynx. Part 1 deals with its development and division, the laryngeal skeleton and joints, the insertion structures of the vocal folds and the laryngeal musculature and describes new insights into the mineralization and ossification of the laryngeal skeleton and their implications for phonation, arytenoid subluxation, degenerative joint changes and the biomechanics of vocal cord insertion.

Arytenoid cartilage dislocation: a 20-year experience

SUMMARY

Arytenoid cartilage dislocation is an infrequently diagnosed cause of vocal fold immobility. Seventy-four cases have been reported in the literature to date. Intubation is the most common origin, followed by external laryngeal trauma. Decreased volume and breathiness are the most common presenting symptoms. We report on 63 patients with arytenoid cartilage dislocation treated by the senior author (RTS) since 1983. Significantly more posterior than anterior dislocations were represented. Although reestablishing joint mobility is difficult, endoscopic reduction should be considered to align the heights of the vocal processes. This process may result in significant voice improvement even long after the dislocation. Strobovideolaryngoscopy, laryngeal electromyography, and laryngeal computed tomography (CT) imaging are helpful in the evaluation of patients with vocal fold immobility to help distinguish arytenoid cartilage dislocation from vocal fold paralysis. Familiarity with signs and symptoms of arytenoid cartilage dislocation and current treatment techniques improves the chances for optimal therapeutic results.

Arytenoid cartilage dislocation caused by a double-lumen endobronchial tube

Following surgery requiring the use of a double-lumen endobronchial tube, a patient immediately complained of persistent severe hoarseness. On the third day after the operation, fibreoptic laryngoscopy revealed posterolateral dislocation of the left arytenoid cartilage. By the sixth day of the operation, a slight improvement was observed in the hoarseness without treatment and a spontaneous recovery of arytenoid cartilage dislocation was expected. The patient did not consent to surgical treatment, and therefore a conservative therapy was selected. Ten weeks after the operation, it was found that the dislocated left arytenoid cartilage had spontaneously repositioned and the patient regained his normal voice. The causes and treatment options are discussed.

Long-term complications of artificial airways

In summary, long-term complications of artificial airways are rare but important sequelae of artificial airways. Many of the potential long-term complications of translaryngeal intubation and tracheotomy are similar and overlapping. Although most patients who undergo these procedures tend to tolerate them without difficulties, significant morbidity and mortality may occur. Identifying the exact cause of the complication may not be possible at times, due to the multiple risk factors involved in the pathogenesis. It is hoped that understanding these potential complications will lead to a more vigilant preventive measures during the institution of long-term artificial airways and a judicious early search for the underlying pathology when a complication is suspected.

Hoarseness after laryngeal blunt trauma: a differential diagnosis between an injury to the external branch of the superior laryngeal nerve and an arytenoid subluxation. A case report and literature review

Arytenoid subluxation is a well-known cause of hoarseness due to incomplete glottic closure with intact inferior laryngeal nerves after severe laryngeal trauma. We report the case of a young man presenting after laryngeal blunt trauma with hoarseness, easy fatigue during phonation, marked difficulty with his high-pitch and singing voice and decreased phonation time, but intact function of both inferior laryngeal nerves, intact endolaryngeal mucosa sensibility and normal CT scans of the larynx and the neck. Due to the asymmetric anteromedial position of the right arytenoid with incomplete glottic closure, the primary diagnosis was arytenoid subluxation, and the patient was referred for instantaneous relocation therapy. The stroboscopic and electromyographic diagnosis of a unilateral paresis of the external branch of the right superior laryngeal nerve caused the therapy to be changed. Without repositioning, the patient had a total recovery of voice quality when the paresis receded 2 months later. In conclusion, the unilateral paresis of the external branch of the superior laryngeal nerve after laryngeal blunt trauma is reported here for the first time. Although the clinical findings are familiar sequelae of thyroid surgery, they may be misdiagnosed as arytenoid subluxation after laryngeal blunt trauma. Stroboscopy and electromyography permitted the correct diagnosis.

Impact of vocal cord paralysis on cricoarytenoid joint

To demonstrate structural changes in the cricoarytenoid joint after recurrent laryngeal nerve paralysis, we performed a laboratory investigation of fixed arytenoid cartilages from adult humans obtained during laser surgical arytenoidectomy in cases of bilateral vocal fold paralysis, analyzing the articular cartilage, the joint capsule, and the attached laryngeal musculature. Ten arytenoid cartilages from adult humans were studied by means of histology, as well as scanning and transmission electron microscopy. After long-standing denervation (>6 months), all arytenoid cartilages showed degenerative changes in their joint surface structure at various levels of intensity. The articular surface revealed fibrillation in some places, demasking of collagen fibrils next to the joint surface, and formation of chondrocyte clusters near the joint surface. All specimens also showed muscle atrophy. We conclude that long-standing recurrent laryngeal nerve paralysis does not result in ankylosis of the cricoarytenoid joint, as assumed, but the articular cartilage undergoes structural changes comparable to those in osteoarthritis. Structural changes in the articular cartilage and in the surrounding musculature hamper efforts at joint function recovery, as do procedures aiming solely at either medialization or lateralization of the vocal fold.

The cricoarytenoid joint capsule and its relevance to endotracheal intubation

Impaired movement of the cricoarytenoid joint with hoarseness and immobility of the vocal ligament may occur as a consequence of endotracheal intubation. Little is known about the cricoarytenoid joint capsule and its role in intubation. We investigated the joint capsules of 48 cricoarytenoid joints by means of gross anatomy microscopy, histology, and scanning electron microscopy; 30 unfixed cadaver larynges were also subjected to attempts to simulate traumata such as those that may occur during intubation trials. The larynges were intubated with the arytenoid tip entering the lumen of the tracheal tube or extubated with the cuff of the tube only partially deflated. Subsequently, i.e., after dissecting the left and right cricoarytenoid joint from each larynx, the morphologic changes induced experimentally were analyzed by using histologic methods. The cricoarytenoid joint was found to be lined by a wide joint capsule. Unexpectedly large and intensively vascularized synovial folds projected into the joint cavity. After simulation of intubation and extubation, histologic analysis revealed injuries to the synovial folds and joint surface impressions, but no trauma or rupture of the outer joint capsule. We conclude that laxity of the joint capsule and the large synovial folds are predisposing factors for intubation trauma of the cricoarytenoid joint, potentially leading to hemarthros and finally to cricoarytenoid joint dysfunction.

IMPLICATIONS

The present study illustrates by morphological investigations and intubation experiments that laxity of the joint capsule and large synovial folds are predisposing factors for intubation trauma of the cricoarytenoid joint, potentially leading to hemarthrosis and finally to cricoarytenoid joint dysfunction.

Osteoarthritis in cricoarytenoid joint

OBJECTIVE

Occurrence of osteoarthritis is a frequent event of limb joints in people over 40 years of age. The human cricoarytenoid joint is comparable with the joints of the limbs despite its structure and extracellular matrix composition. To date, little is known about the occurrence of osteoarthritis in the human cricoarytenoid joint.

METHODS

Sixty-eight cricoarytenoid joints (42 male and 26 female, age 25-98 years) were analysed by means of histology, lectin histochemistry, immunohistochemistry as well as scanning and transmission electron microscopy.

RESULTS

About 50% of the investigated cricoarytenoid joints aged over 40 years show degenerative changes in their joint surface structure at varying levels of intensity. The articular cartilage surface is fibrillated in some places and sometimes shows fissures. A demascing of collagen fibrils next to the joint surface and a loss of proteoglycans in the upper cartilage layers can be observed. Chondrocytes near the joint surface appear as voluminous chondrocyte clusters. The clusters and the superficial cartilage layer show a positive reaction to type VI collagen antibodies. The distribution patterns of lectins are completely changed in fibrillated cartilage areas.

CONCLUSION

Degenerative alterations in diarthrodial joints resembling osteoarthritis can occur in the joints of the larynx. These structural changes of the articular cartilage are comparable to osteoarthritis of the limb joints. Osteoarthritis in the cricoarytenoid joint may lead to impaired movements of the arytenoid cartilages. Functionally the structural changes may lead to negative consequences during vocal production, such as impaired vocal quality and reduced vocal intensity.

Composition of the extracellular matrix in human cricoarytenoid joint articular cartilage

The extracellular matrix of the human cricoarytenoid joint articular cartilage is involved in different pathological changes. Interestingly, in contrast to the limb joints, the extracellular matrix composition of the healthy cricoarytenoid joint articular cartilage has not yet been elucidated except by some light microscopical investigations. The present study investigates the extracellular matrix components of the cricoarytenoid joint articular cartilage by means of light microscopy, immunohistochemistry, transmission electron microscopy and scanning electron microscopy and compares them with the limb joints for a better understanding of their involvement in joint disease. Chondrocytes near the joint surface of the cricoid and arytenoid cartilage differ from chondrocytes of deeper cartilage layers. The extracellular matrix of the articular cartilage contains chondroitin-4-sulfate, chondroitin-6-sulfate and keratansulfate as well as collagen types II, III, VI, IX and XI. Type-III-collagen shows a special distribution throughout the joint cartilage. In deeper cartilage layers, type-III-collagen occurs only pericellularly; in higher cartilage layers type-III-collagen is also located territorially and interterritorialy in small amounts. Scanning and transmission electron microscopy have revealed the articular surface of the cricoid and arytenoid cartilage to consist of a network of irregularly organized collagen fibrils, which are lined by a layer of electron dense material. The network coats subjacent collagen bundles which descend obliquely downward and intermingle at right angles in the middle part of the articular cartilage with collagen bundles of the deeper cartilage zones. The articular cartilage surface shows structural characteristics which differ from the underlying cartilage. The superficial electron dense layer possibly plays a role in the lubrication of the articular cartilage surface. The alignment of the fibrillar structures in the articular cartilage of the cricoarytenoid joint varies from those of the limb joints based on the different strain occurring during arytenoid movement. Nevertheless, the human cricoarytenoid joint articular cartilage can be compared with the joints of the limbs despite its extracellular matrix composition and its involvement in joint pathology. Evidence of type III collagen in the outermost layer of the articular cartilage of the cricoarytenoid joint presents a peculiarity, which has yet not be demonstrated in the articular cartilage of limb joints.