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PubMed1989

[An experimental study on surgical treatment of tracheomalacia-- methods for making models of tracheomalacia and development of a new operative method].

To develop a new surgical method for the repair of tracheobronchomalacia, we conducted experiments on dogs. First, we created malacic models by fracturing or resecting 5 to 10 tracheal cartilages. The bearing strength of the tracheal lumen became remarkably weakened, and bronchoscopic examination revealed tracheal collapses during coughing. Second, we tried external stenting of the malacic tracheae with prostheses. In 11 dogs, a prosthesis composed of Silastic sheet and Marlex mesh was sutured to the malacic segments of trachea. The connective tissue around the prosthesis increased in amount and the tracheal wall became firmer with time. However, mucosal defects around the sutures were found in 4 of the dogs. Those defects were probably due to injury to capillaries by the suturing procedures. Therefore, instead of suturing, we decided to try adhesives for fixation of the prosthesis to the trachea. We tested three adhesives: PUP (polyurethane-prepolymer), cyanoacrylate and fibrin glue. In five dogs using cyanoacrylate, the tracheal walls were remarkably hardened within 3 to 8 months. In eight dogs using fibrin glue for fixation of Marlex mesh to the malacic trachea the results were satisfactory. With fibrin glue, the tracheal walls after 3 to 8 months had almost the same strength as the average of normal tracheae.

Animals↗
PubMed1986

Contemporary surgery of tracheomalacia.

During the past 7 years, 41 infants were treated for tracheomalacia. The etiology was primary/congenital in 28 patients and secondary/acquired in 16 patients, of which three patients were originally in the primary group. The primary group consisted of patients with pulsatile tracheomalacia but normal vascular anatomy, idiopathic disease, or tracheomalacia associated with tracheoesophageal fistula. The secondary group consisted of patients with tracheal compression due to great vessel abnormalities, or tracheostomy-tracheomalacia. Diagnosis was made by bronchoscopic demonstration of major (greater than 40%) collapse of the trachea. Treatment consisted of conservative therapy, tracheostomy, aortopexy, or tracheal reconstruction. The 15 patients with mild primary tracheomalacia treated conservatively had gradual resolution of symptoms by the age 2 years. All five patients with primary tracheomalacia treated by tracheostomy developed secondary tracheomalacia and/or cicatrix at the tracheostomy site. In the 9 patients with primary tracheomalacia treated by aortopexy, 5 are symptom free, 1 is improved, 1 had recurrent apnea, and 2 died, 1 from unrelated complications. Of the 10 patients in the acquired group treated by aortopexy, 6 were cured, 2 were improved, and 2 failed. Of 6 patients with tracheostomy-tracheomalacia, 3 were eventually extubated, 1 had major reconstruction, and 2 had tracheostomies when lost to follow-up at 1 and 5 years. Our conclusions are that, when feasible, conservative therapy in milder cases is preferred, and no perfect operation currently exists for severe tracheomalacia although aortopexy may have less long-term morbidity than tracheostomy.

Aorta, Thoracic↗
PubMed2005

Interventions for primary (intrinsic) tracheomalacia in children.

BACKGROUND: Tracheomalacia, a disorder of the large airways where the trachea is deformed or malformed during respiration is commonly seen in tertiary paediatric practice. It is associated with a wide spectrum of respiratory symptoms from life threatening recurrent apnea to common respiratory symptoms such as chronic cough and wheeze. Current practice following diagnosis of tracheomalacia include medical approaches aimed at reducing associated symptoms of tracheomalacia, ventilation modalities of continuous positive airway pressure (CPAP) and bi-level positive airway pressure (BiPAP) and, surgical approaches aimed at improving the caliber of the airway (airway stenting, aortopexy, tracheopexy). OBJECTIVES: To evaluate the efficacy of medical and surgical therapies for children with intrinsic (primary) tracheomalacia. SEARCH STRATEGY: The Cochrane Central Register of Controlled Trials (CENTRAL), the Cochrane Airways Group Specialised Register, MEDLINE and EMBASE databases were searched by the Cochrane Airways Group. The latest searches were performed in Feb 2005. SELECTION CRITERIA: All randomised controlled trials of therapies related to symptoms associated with primary or intrinsic tracheomalacia. DATA COLLECTION AND ANALYSIS: Results of searches were reviewed against pre-determined criteria for inclusion. No eligible trials were identified and thus no data were available for analysis. MAIN RESULTS: No randomised controlled trials (RCTs) that examined therapies for intrinsic tracheomalacia were found. Eight of the more recent (last 11 years) non randomised controlled trials reported a benefit from the various surgical interventions. The success was however not universal and in some studies severe adverse events occurred. AUTHORS' CONCLUSIONS: There is currently an absence of evidence to support any of the therapies currently utilised for management of intrinsic tracheomalacia. It is unlikely that any RCT on surgically based management will ever be available for children with severe life threatening illness associated with tracheomalacia. For those with less severe disease, RCTs are clearly needed. Outcomes of these RCTs should include measurements of the trachea and physiological outcomes in addition to clinical outcomes.

Adolescent↗
PubMed2000

The anterior mediastinal approach for management of tracheomalacia.

BACKGROUND: Tracheomalacia occurs as a primary developmental defect or may be secondary to vascular compression. It is common in association with esophageal atresia and tracheoesophageal fistula. Collapse of the weak trachea is a cause of recurrent respiratory symptoms but may be severe and life threatening. METHODS: Between 1978 and 1999 at Sheffield Children's Hospital and The Royal Manchester Children's Hospital, of 16 children with clinically significant symptoms of tracheomalacia 8 underwent combined aortopexy and tracheopexy, 1 had aortopexy alone, 4 only had a tracheopexy, and 3 had tracheal reinforcement with free costal cartilage ring grafts. The surgical approach was limited to a low cervical skin crease incision with a midline manubrial split providing extrapleural access to the anterior mediastinum and allowing for all surgery under direct unimpaired vision. RESULTS: Ten children did not require postoperative ventilatory support. Four underwent ventilation for a few hours or days. One child required CPAP for 4 months for residual tracheomalacia and a further child, who had 3 operations to insert 11 costal cartilage ring grafts, underwent ventilation intermittently for 6 months. Adequate tracheal patency could be verified by intraoperative tracheoscopy and was sustained postoperatively so that only 1 child with associated bilateral vocal cord paralysis came to tracheostomy. Four children required prolonged hospitalization because of residual tracheomalacia, 2 for bronchomalacia and 2 because of esophageal narrowing leading to further surgery. All other children were fit for discharge within 10 to 30 days of surgery. Long-term follow-up has confirmed sustained tracheal improvement and resolution of the life-threatening features of tracheomalacia. CONCLUSIONS: The authors recommend the low skin crease transmanubrial approach, as described by Vaishnav and MacKinnon, for tracheopexy, aortopexy and for tracheal reconstruction for tracheomalacia. The approach gives excellent access for surgery under direct vision through a relatively avascular plane. It is associated with less morbidity than a conventional thoracotomy and leaves a more acceptable aesthetic scar.

Child, Preschool↗
PubMedDate not supplied

Acquired tracheomalacia: detection by expiratory CT scan.

PURPOSE: The purpose of this work was to determine whether cross-sectional area and coronal and sagittal diameter measurements of the trachea between inspiration and end-expiration on CT are significantly different between patients with acquired tracheomalacia and those without this condition. METHOD: Inspiratory and end-expiratory CT scans of the trachea of 23 normal patients and 10 patients with acquired tracheomalacia were analyzed. Percent changes in cross-sectional area, coronal, and sagittal diameters were calculated. RESULTS: For patients with tracheomalacia, mean percent changes in the upper and middle trachea between inspiration and expiration were 49 and 44%; mean changes in the coronal and sagittal diameters in the upper and middle tracheal were 4 and 10% and 39 and 54%, respectively. Control group mean percent changes in the upper and middle tracheal area were 12 and 14%, respectively, and mean changes in the coronal and sagittal diameters in the upper and middle trachea were 4 and 4% and 11 and 13%, respectively. Significant differences were calculated for changes in cross-sectional area and sagittal diameter between groups (p < 10-5). Based on receiver operator curve analysis, a > 18% change in the upper trachea and 28% change in the midtrachea between inspiration and expiration were observed; the probability of tracheomalacia was 89-100%. The probability of tracheomalacia was > 89%, especially if the change in sagittal diameter was > 28%. CONCLUSION: By measuring changes in tracheal cross-sectional area and sagittal diameters between inspiratory and end-expiratory CT, a significant difference can be identified between normal patients and those with acquired tracheomalacia.

Adult↗
PubMed2003

Tracheomalacia incidentally detected on CT pulmonary angiography of patients with suspected pulmonary embolism.

OBJECTIVE: The aim of this study was to determine the frequency of tracheomalacia incidentally detected on CT pulmonary angiography in patients with suspected pulmonary embolism. MATERIALS AND METHODS: CT records of 163 consecutive patients imaged with CT pulmonary angiography for suspected pulmonary embolism were retrospectively reviewed at our institution. The patients underwent CT pulmonary angiography with three different types of CT scanners. All images were visually assessed by two thoracic radiologists for excessive collapse of the trachea and the main bronchi. The cross-sectional area of the lumen at the site of maximal collapse of the airway was measured, and the percentage of luminal narrowing was calculated by comparing it with the cross-sectional area of the airway lumen at an adjacent area without collapse. We defined tracheomalacia as a 50% or greater decrease in tracheal lumen. RESULTS: Sixteen (10%) of 163 patients showed evidence of tracheomalacia (seven men, nine women; age range, 41-95 years; mean age, 72 years). The most common presenting symptom was shortness of breath, which was observed in 13 (81%) of 16 patients. Known causes of tracheomalacia were found in 15 (94%) of 16 patients, prior intubation was confirmed in 12 patients, and history of asthma or chronic obstructive pulmonary disease was observed in five patients. CONCLUSION: Tracheomalacia is a relatively common incidental finding on CT pulmonary angiography studies. The central airways, as well as pulmonary vasculature, should be reviewed carefully for clinical interpretation in patients with suspected pulmonary embolism. Paired expiratory-inspiratory CT is recommended if patients present with known causes of tracheomalacia such as prior intubation, chronic obstructive pulmonary disease, or asthma.

Adult↗
PubMed1988

Tracheomalacia from compressing goiter: management after thyroidectomy.

Tracheomalacia may result from prolonged compression by expanding goiter, particularly within the confines of the thoracic inlet. Constriction of the upper airway by the growing goiter may be indication for operation, but the residual problem of tracheomalacia after thyroidectomy is a life-threatening postoperative complication. Examples of postoperative tracheomalacia in patients with neglected goiters endemic in the third world or recurrent goiter with airway compromise in a western medical center referral practice are described for development of management methods. Two patients with lethal postthyroidectomy tracheomalacia led me to anticipate this complication in certain identifiable high-risk patients in my own practice, and the cases of five patients are described for whom several techniques of tracheal support were attempted. One patient, for whom staged tracheoplasty was planned, opted for tracheostomy, whereas four patients have had adequate tracheal airways restored by extrinsic support. One was treated by subtotal thyroidectomy with tracheal suspension; one by staged thyroid reductions; two were treated by creation of extrinsic tracheal neo-rings constructed of surgical wire and vascular prostheses. The patient with the most dramatic airway impairment from the most extensive tracheomalacia experienced very satisfactory airway security. A second patient was also supported by the prosthetic rings but extruded one of them, possibly because of tracheostomy contamination. Until tracheal replacement or better tolerated prosthetic or biologic supports are devised, tracheomalacia will remain a vexing problem complicating thyroidectomy for long-standing or recurrent airway-compressing goiter.

Adult↗
PubMed1991

Tracheomalacia in Hallermann-Streiff syndrome.

We report on a white boy with Hallermann-Streiff syndrome (HSS) who also had tracheomalacia. Chronic respiratory insufficiency led to biventricular failure and death at age 6 months. There have been no previously reported cases of Hallermann-Streiff syndrome with documented tracheomalacia. However, there may be cases in which tracheomalacia may have been present, but not diagnosed. The literature contains 6 HSS cases with severe respiratory symptoms. Tracheomalacia should be considered in a patient with HSS who presents with an unusual cry, stridor, choking, or apnea. With the availability of surgery and supportive treatment, early diagnosis of tracheomalacia in these patients may prevent death and secondary neurologic insult from acute hypoxia.

Cartilage Diseases↗
PubMed1991

An experimental model for the surgical correction of tracheomalacia.

Tracheomalacia may result from large intrathoracic goiters. Due to the chronic compression, particularly within the confines of the thoracic inlet, the tracheal wall weakens, with disintegration of some of the cartilaginous rings. Tracheomalacia can cause acute airway distress, particularly during the post-operative period, and may occasionally result in death. The other major cause of tracheomalacia is related to either prolonged endotracheal intubation or over-inflation of the tracheostomy cuff. While various techniques such as internal stenting, external support devices, tracheostomy, and tracheal resection have been used based on individual circumstances, no one method appears to be perfect. To further study this difficult problem, an experimental model of tracheomalacia was created in eight dogs. Six to seven rings of the tracheal cartilages were dissected submucosally. More than half of the circumference of the tracheal rings was resected. The tracheal walls were reconstructed with polytetrafluoroethylene (PTFE) grafts. The grafts strengthened the tracheal wall without causing luminal constriction. Tracheostomy was not performed on any of the dogs. All dogs tolerated the procedure well and were extubated at the conclusion of the experiment. The dogs were followed for 4 to 6 months and then sacrificed so that the tracheal wall could be examined histologically. There was considerable fibrosis leading to stiff neotrachea. The results of this experimental technique for prosthetic reconstruction to counteract problems simulating tracheomalacia are very encouraging.

Animals↗
PubMed2006

Clinically relevant tracheomalacia after repair of esophageal atresia: the role of minimal intra-operative dissection and timing for aortopexy.

BACKGROUND: Tracheomalacia is associated with esophageal atresia (EA), but may go unnoticed from external splinting forces. Intra-operative dissection with fistula division releases external splinting, revealing tracheomalacia only post-operatively. Analysis of surgical technique may disclose an iatrogenic etiology. METHODS: From 1995 - 2004, 44 neonates underwent surgery for EA. All patients underwent pre-, intra- and postoperative bronchoscopy. Operative and bronchoscopic notes were studied for malacia, and extensive dissection of the esophagus and fistula from the trachea. RESULTS: Surgical mortality was 6.8 %. Pre-operative tracheomalacia was diagnosed in 3 patients, who eventually fared well. In 17 other patients, the pre-operative bronchoscopy was negative, but airway obstruction developed post-operatively. Tracheomalacia was documented at the site of the former fistula and surgical release maneuvers. Aortopexy was required in 5 instances, whereas 12 others with malacia were managed conservatively. CONCLUSIONS: Mediastinal connective tissue and the fistula may splint open the marginally diseased airway in patients with EA, the lack of which may disclose previously unknown tracheomalacia after repair. When aggressive release maneuvers have been required, early aortopexy may be preferred to ventilator dependency.

Airway Obstruction↗
PubMed2000

Efficacy of transoral intraluminal Wallstents for tracheal stenosis or tracheomalacia.

OBJECTIVES: The efficacy and safety of intraluminal Wallstent Endoprosthesis (Boston Scientific/ Medi-Tech, Quincy, MA) placement to restore airway patency in patients with tracheal stenosis or tracheomalacia are unknown. STUDY DESIGN: Retrospective review in setting of tertiary, referral, and academic center. METHODS: A retrospective review of 13 consecutive patients over a 2-year period who underwent transoral resection of tracheal stenosis and immediate transoral Wallstent placement. One patient had tracheomalacia. All of the patients were considered at high risk for transcervical surgery or had failed prior traditional open procedures. RESULTS: The average patient age was 54.2 years, with nine male and four female patients. All had Cotton/Myer stenoses (grades II to IV) with moderate to severe degrees of inspiratory stridor. Four patients were tracheotomy dependent. The length of stenosis varied from 1 to 4 cm. One patient had a 10-cm segment of tracheomalacia. At the time of writing, none of the patients has had a problem with significant migration or extrusion and most of the patients have incorporated the stent well without any short-term obstructive granulation tissue. After a mean follow-up of 15 months (range, 4-24 mo). 10 of the 12 patients with stenosis (83%) have remained free of any inspiratory noise during breathing. The one patient with tracheomalacia also has remained free of symptoms. CONCLUSIONS: Transoral Wallstents appear to be safe and may be a reasonable alternative in the restoration of airway patency in select patients with tracheal stenosis or tracheomalacia.

Adolescent↗
PubMed2005

Treatment of tracheomalacia with Palmaz stent: a case report.

Tracheomalacia is a potentially life-threatening clinical problem. The expandable Palmaz stent can be used for the treatment of tracheomalacia. We describe a female infant with tracheomalacia who showed respiratory distress the day after birth. Tracheomalacia was diagnosed by bronchoscopic examination, computed tomography and bronchography. At 75 days of age, an expandable metallic stent (Palmaz stent) was inserted into the trachea under fluoroscopic control. The patient's respiratory status improved rapidly. Bronchoscopic examination 6 months after the insertion did not show any granulation tissue. However, in bronchoscopic examination carried out two years later, we detected invasion of the Palmaz stent to the trachea and development of granulation tissue. We think that expandable metallic stent placement should be considered in patients who show intractable respiratory symptoms caused by tracheomalacia in the earlier stages of the treatment. But long-term complications of this procedure are crucial.

Airway Obstruction↗
PubMed1998

Tracheal ring-graft reinforcement in lieu of tracheostomy for tracheomalacia.

Three children with tracheomalacia had tracheal reinforcement with free three-quarter circumference ring grafts of autologous cartilage taken from the costal margin. A low cervical manubrium-splitting approach gave excellent access to the anterior mediastinum and the intrathoracic trachea in two children. The first child, a neonate with oesophageal atresia (OA) and tracheo-oesophageal fistula (TOF), had 11 grafts to support the whole of the trachea from the cricoid to the carina and never required a tracheostomy. For the first 5 years she had frequent pneumonic episodes and on one occasion bilateral pneumothoraces. These episodes and radiographic lung hyperinflation, attributed to distal bronchomalacia, have reduced spontaneously in frequency and severity. At 9 years of age she has a well-supported trachea with palpable cartilage rings in the cervical segment. The trachea has grown to approximately 75% of expected normal size for her age. Another child with tracheomalacia related to innominate-artery compression and who presented with 'dying episodes' was completely relieved and resumed a normal life without a tracheostomy following insertion of four grafts to the intrathoracic trachea. He remains well and symptom-free 8 months postoperatively. A third child had cartilage-graft reinforcement of the lower cervical trachea, including the tracheostomy site, to achieve tracheostomy closure at 16 months of age. Five years later he continues to have a well-supported trachea showing acceptable growth. However, he has ongoing evidence of tracheo-bronchomalacia presenting as expiratory wheezing, lung hyperinflation, and pneumonic episodes that are diminishing spontaneously with growth. Our experience, limited to three children, recommends primary tracheal reinforcement with autologous free costal-cartilage grafts for tracheomalacia in the neonate and young infant. This procedure and the anterior mediastinal approach are well-tolerated, providing instant tracheal support, removing the need for a tracheostomy, and allowing the child's rapid return to the family. Long-term follow-up, presently 9 and 5 years in two children originally presenting with OA and TOF, indicates adequate tracheal growth and an aesthetically acceptable appearance. It is relevant to prognosis that relief of the life-threatening tracheal component exposed the full extent of the bronchial cartilaginous weakness, which has significantly detracted from the quality of life for these two children with OA and TOF-related tracheomalacia.

Cartilage↗
PubMed1997

Tracheomalacia with esophageal atresia and tracheoesophageal fistula in fetal rats.

BACKGROUND: Many patients who have esophageal atresia and tracheoesophageal fistula (EA-TEF) have associated tracheomalacia, which is thought to be one of the reasons for respiratory complications after surgical correction of the abnormality. METHODS: In this study, tracheas from Adriamycin-induced EA-TEF fetal rats were examined histologically and relevant cross-sectional parameters of the tracheas were measured. RESULTS: The tracheal lumen in tracheomalacia was small and irregular, losing its normal "D" shape. In most rats, the cartilaginous ring was broken into two to four segments, making the trachea lose its rigid support. The submucosa was thickened with prominent bulging of its membranous part into the tracheal lumen. The ratio of the inner luminal cross-sectional area to the outer tracheal cross-sectional area in EA-TEF rats was 15.7%, compared with a control ratio of 47.2%. In EA-TEF rats, the length of the cartilaginous ring was significantly shortened (P < .001), but not the length of membranous trachea, thus resulting in a cartilaginous/membranous (C/M) ratio of 1.55:1, markedly lower than that of normal rats (4.34:1, P < .001). The reduction of anterior-posterior diameter of the tracheal lumen was more marked than that of the transverse diameter. CONCLUSIONS: These observations suggest that the trachea in EA-TEF rats has a smaller lumen and is more flaccid than normal, making it prone to airway obstruction. The fact that tracheomalacia developed only in fetuses who had EA-TEF indicates that the factors that result in EA-TEF also cause tracheomalacia.

Airway Obstruction↗
PubMed2001

[Tracheomalacia and tracheal dyskinesias].

Tracheomalacia is characterized by an expiratory tracheal collapse. The revealing clinical features usually occur after a symptom-free period during the first year of life (during the first three months in 60% of cases): mainly stridor, wheezing, chronic cough, apnoeic attacks, and difficult breathing. Tracheoscopy allows the differentiation of primary tracheomalacia and tracheomalacia secondary to pressure on the trachea from the vascular ring or mediastinal tumour. Tracheomalacia is also frequently associated with oesophageal atresia. Surgical treatment is indicated in severe and secondary forms.

Apnea↗
PubMed1998

Understanding tracheomalacia.

Tracheomalacia is an abnormality of the trachea that probably is present to some degree in all infants and children with oesophageal atresia. It causes the trachea to collapse during breathing, leading to obstruction of the upper airway. Our knowledge of the structural abnormalities underlying tracheomalacia is limited, mainly because patients with oesophageal atresia usually survive. Recently, the Adriamycin-induced rat model of oesophageal atresia and tracheomalacia has clarified some aspects of its pathology and the factors which may influence its development. The rat model suggests that the same detrimental factors that cause oesophageal atresia might also affect the development of the trachea, and that anomalous great vessels may exacerbate the severity of tracheomalacia locally.

Airway Obstruction↗
PubMedDate not supplied

Cartilage regeneration using slow release of bone morphogenetic protein-2 from a gelatin sponge to treat experimental canine tracheomalacia: a preliminary report.

We investigated whether saber sheath-type tracheomalacia could be treated by the slow release of bone morphogenetic protein (BMP)-2 from a gelatin sponge. A 1 cm gap was made in the middle portion of each of 10 consecutive tracheal cartilage rings in the canine cervix (control group, n = 3), then a gelatin sponge containing 12 microg of BMP-2 solution was implanted in the gap (12 microg group, n = 3). In another group (120 microg + P group, n = 3), the implanted gelatin sponge contained 120 microg of BMP-2 solution, and the gap was covered with periosteum. All of the control dogs developed saber sheath-type tracheomalacia, whereas tracheomalacia was not observed in the 12 microg and 120 microg + P groups. In the 12 microg group, fibrous cartilage was observed at the ends of the cartilage stumps. In the 120 microg + P group, newly formed bone and cartilage were observed to form a bridge between the cartilage stumps. The regeneration of cartilage or bone induced by the slow release of BMP-2 from a gelatin sponge might be useful for treatment of tracheomalacia.

Animals↗
PubMed2006

Tracheal morphology in patients with tracheomalacia: prevalence of inspiratory lunate and expiratory "frown" shapes.

OBJECTIVE: To identify the spectrum of tracheal morphologies in patients with tracheomalacia, and to determine the prevalence of specific inspiratory (lunate) and expiratory (frown) shapes that have been associated with this condition. MATERIALS AND METHODS: A retrospective review was performed of a consecutive series of patients with bronchoscopically-proven tracheomalacia who were imaged with inspiratory and dynamic-expiratory computed tomography (CT). The CT images of each patient were reviewed in a blinded, randomized fashion by an experienced thoracic radiologist. For each case, the shape of the trachea at end-inspiration and dynamic expiration was classified using specific tracheal morphologies described in the literature. RESULTS: The study population included 17 patients, with a mean age of 54 years. At inspiration, 16 (94%) of 17 subjects demonstrated a normal tracheal configuration (round, oval, horseshoe, or inverted-pear shape), and 1 (6%) of 17 subjects demonstrated an abnormal "lunate" tracheal configuration (coronal: sagittal ratio >1). At expiration, 9 (53%) of 17 subjects demonstrated a crescenteric, "frown" shape; 1 (6%) subject demonstrated complete collapse; and 7 (41%) subjects demonstrated other morphologies. CONCLUSIONS: Inspiratory tracheal morphology is almost always normal in patients with tracheomalacia, with a lunate configuration only rarely observed. In contrast, an expiratory "frown sign" is observed in approximately half of patients with this condition. This sign has the potential to aid the detection of tracheomalacia when patients inadvertently breathe during routine CT scans.

Adult↗