Tracheobronchomalacia, often shortened to TBM, is a condition in which the walls of the trachea and large bronchi are abnormally soft and prone to collapsing during breathing, especially when you exhale, cough, or strain. The collapse happens because of weakened cartilage in the front of the airway, excessive flexibility of the membrane along the back, or both.1PubMed Central. Tracheomalacia and Tracheobronchomalacia in Pediatrics: An Overview of Evaluation, Medical Management, and Surgical Treatment The condition is more common than most people realize and routinely gets mistaken for asthma, chronic bronchitis, or a stubborn cough that just won’t go away.
Why TBM Gets Confused with Asthma and Bronchitis
One of the most frustrating aspects of TBM is how easily it hides behind other diagnoses. The symptoms overlap heavily with more familiar conditions: a barking or honking cough, wheezing, shortness of breath during exertion, and recurrent respiratory infections. There is no single telltale sign that screams TBM, which means many people spend years on inhalers, steroids, and antibiotics that never fully resolve the problem.2PubMed. Tracheobronchomalacia
A classic red flag is a cough or wheeze that does not respond to standard asthma treatments. If you’ve been told you have asthma but your rescue inhaler barely makes a dent, or if pulmonary function tests show flow limitations that don’t fit typical asthma patterns, TBM should be on the list. The difficulty is that TBM also coexists with other lung conditions like COPD, complicating the picture further. A person can have both COPD and TBM, and the collapsing airways amplify the symptoms of both.
What Actually Happens Inside the Airway
In a healthy airway, the trachea and main bronchi stay open during both inhalation and exhalation thanks to C-shaped rings of cartilage along the front and sides and a strip of muscular membrane across the back. During forceful exhalation, some narrowing is normal. In TBM, that narrowing goes too far. The cartilage rings lose their structural stiffness, the posterior membrane bulges forward into the airway, or both occur together, and the airway can narrow dramatically or even slam shut.
Researchers distinguish TBM from a related condition called excessive dynamic airway collapse (EDAC). In TBM, the cartilage itself is weakened. In EDAC, the cartilage is structurally fine, but the membrane along the back of the airway is overly elastic and balloons inward. The two conditions can look similar on a quick glance, but the underlying structural problem differs, and that distinction can affect treatment decisions.3PubMed. Tracheobronchomalacia and excessive dynamic airway collapse
The shape of the collapse varies, too. In what researchers call “saber-sheath” malacia, the cartilage gives way along a single line and the airway flattens side to side. In circumferential malacia, cartilage weakness is more widespread, and the airway narrows from all directions.4PubMed Central. A novel ex vivo tracheobronchomalacia model for airway stent testing and in vivo model refinement These different collapse patterns matter when doctors are deciding what type of stent or surgical approach fits best.
Causes and Associated Conditions
TBM can be congenital or acquired. In infants and young children, congenital TBM often results from abnormal development of the airway cartilage. Some babies are born with incomplete or entirely missing cartilage rings, a condition known as ring agenesis, which leads to diffuse and severe airway collapse.5Respiratory Medicine Case Reports. Face-mask CPAP as palliative support for diffuse tracheobronchomalacia from ring agenesis in an infant In many pediatric cases, mild-to-moderate TBM improves as the child grows and the cartilage stiffens, though severe forms can be life-threatening.
In adults, TBM is more often acquired. Prolonged intubation can damage the cartilage from the inside out. Chronic inflammation from COPD or recurrent infections gradually weakens the airway wall over time. External compression from enlarged blood vessels, thyroid masses, or tumors can also soften and deform the cartilage.
Certain systemic diseases increase TBM risk. Relapsing polychondritis, a rare autoimmune condition that attacks cartilage throughout the body, can cause sudden and severe TBM when it hits the airways.6PubMed Central. Sudden Respiratory Failure due to Tracheobronchomalacia by Relapsing Polychondritis, Successfully Rescued by Multiple Metallic Stenting and Tracheostomy Ehlers-Danlos syndromes, a group of connective tissue disorders, have also been associated with TBM as part of their broader respiratory effects, which can include chest wall deformities and spinal curvature alongside floppy airways.7American Journal of Medical Genetics, Part C: Seminars in Medical Genetics. Respiratory manifestations in the Ehlers–Danlos syndromes
How TBM Gets Diagnosed
The reference standard for diagnosing TBM is dynamic flexible bronchoscopy, in which a thin camera is threaded into the airways while the patient is breathing or coughing so doctors can watch the airway walls in real time. The catch is that even this gold standard has some inconsistency. Different observers looking at the same bronchoscopy footage don’t always agree on exactly how much the airway is collapsing, which introduces a layer of uncertainty into the diagnosis.8PubMed. Evaluation of tracheobronchomalacia by dynamic flexible bronchoscopy. A pilot study
CT imaging offers a less invasive alternative, but the technique matters. A standard chest CT taken at the end of a breath captures only a snapshot and tends to underestimate how much the airway actually collapses. Dynamic expiratory CT, where images are acquired while the patient actively forces air out, consistently shows significantly more collapse. One study found that dynamic expiration revealed roughly 50 to 58 percent airway narrowing at key points, compared with only 29 to 36 percent on end-expiratory images.9PubMed. Tracheobronchomalacia: comparison between end-expiratory and dynamic expiratory CT for evaluation of central airway collapse A separate study confirmed the same pattern at different airway levels, finding that dynamic imaging always identified more cases of TBM regardless of which threshold was used.10PubMed. Multi-detector CT evaluation in patients suspected of tracheobronchomalacia: comparison of end-expiratory with dynamic expiratory volumetric acquisitions The takeaway is that if your CT was only done at end expiration, a normal-looking result doesn’t necessarily rule TBM out.
The Threshold Problem
One of the most contentious questions in TBM care is how much collapse counts as pathological. For years, the textbook definition used a 50 percent reduction in cross-sectional airway area as the cutoff. The problem with that number is that many perfectly healthy people meet it. Studies of volunteers without any respiratory symptoms have shown that a substantial proportion of them exhibit 50 percent or more collapse during forced exhalation.11PubMed Central. Current concepts in severe adult tracheobronchomalacia: evaluation and treatment
Because of that, major centers now consider complete or near-complete collapse, meaning 90 percent or more reduction in airway area, as the threshold for severe TBM that might warrant intervention.12PubMed. Tracheobronchomalacia in adults This is a real and meaningful shift. A person told they have TBM based on 50 percent collapse during a CT scan might not actually need treatment at all. The diagnosis alone isn’t the question; the question is whether the collapse is severe enough to explain the symptoms and whether fixing it would help. That distinction matters enormously when weighing whether to proceed with stenting or surgery.
Non-Surgical Treatment Options
For people with mild or moderate TBM, treatment often starts with managing the underlying conditions that make it worse: treating COPD, controlling reflux, optimizing inhaler technique, and addressing recurrent infections. These measures won’t fix the floppy airway, but they can reduce the forces that provoke collapse and lower the overall symptom burden.
Continuous positive airway pressure, or CPAP, acts as a pneumatic splint. The constant airflow pressure keeps the airway walls propped open, counteracting the tendency to collapse. This approach was first described in adults with severe TBM who weren’t responding to standard medical therapy, where adding intermittent nasal CPAP improved both lung function measurements and the overall course of the disease.13PubMed. Nasal continuous positive airway pressure in the treatment of tracheobronchomalacia More recent work has shown that nighttime CPAP can relieve symptoms in adults with excessive airway collapse even when sleep studies are otherwise normal, suggesting the benefit comes from airway splinting rather than treating sleep apnea itself.14PubMed Central. Nocturnal continuous positive airway pressure offers symptomatic benefit in excessive dynamic airway collapse despite normal sleep study
CPAP has also been used in infants with severe congenital TBM. In one case involving a baby with extensive cartilage ring agenesis whose airway was not suitable for surgical reconstruction, face-mask CPAP delivered during sleep and after feedings stabilized oxygen levels and reduced episodes of turning blue at a pressure of just 6 cmH₂O.15Respiratory Medicine Case Reports. Face-mask CPAP as palliative support for diffuse tracheobronchomalacia from ring agenesis in an infant The idea is that sleep and the period after eating are the windows when the infant’s airway is most vulnerable to collapse, so targeted CPAP during those times provides the greatest benefit.
Stents and Surgical Repair
When TBM is severe and CPAP isn’t enough, the next step in the diagnostic and treatment pathway typically involves temporary airway stents. Silicone or metal stents are placed inside the airway during bronchoscopy to hold it open. These serve a dual purpose: they provide immediate symptom relief, and they function as a test run. If your symptoms improve substantially with a stent in place, that’s good evidence your collapsing airway was the real culprit and that surgical stabilization is worth pursuing.
In one prospective study, 57 patients with severe TBM underwent stent placement for central airway stabilization. Of those, 37 reported meaningful improvement in respiratory symptoms, and 35 were ultimately considered candidates for surgical repair.16PubMed. Tracheobronchoplasty for severe tracheobronchomalacia: a prospective outcome analysis That means about a third of stented patients did not improve enough to be surgical candidates, which underscores why the stent trial matters. Stents left in place long-term carry their own risks, including mucus plugging, migration, and granulation tissue forming around the stent, so they are generally considered a temporary or bridging option rather than a permanent solution.17Chest. COPD-Associated Expiratory Central Airway Collapse: Current Concepts and New Perspectives
The definitive surgical treatment is tracheobronchoplasty, a procedure in which a mesh (usually made of polypropylene) is sewn onto the outside of the airway to reinforce the weakened posterior membrane and restore structural support. The surgery is performed through the chest and typically requires general anesthesia and single-lung ventilation.
Long-Term Results After Surgery
The outcomes data for tracheobronchoplasty have become increasingly encouraging. At five years after surgery, one study found that respiratory quality-of-life scores roughly halved (meaning symptoms were cut in half from baseline), six-minute walking distance improved substantially, and functional status scores climbed from the mid-50s to the low 80s on a 100-point scale.18The Journal of Thoracic and Cardiovascular Surgery. Long-term outcomes of tracheobronchoplasty for severe excessive central airway collapse A separate study evaluating robotic-assisted tracheobronchoplasty found significant improvements in lung function at about two and a half years after the operation, with the amount of air patients could forcefully exhale in one second increasing from a median of 74 percent predicted to 82 percent, and forced vital capacity improving from about 69 percent to 81 percent.19PubMed. Robotic-assisted tracheobronchoplasty: Quality of life and pulmonary function assessment on intermediate follow-up
That said, improvement in measurable airflow and airway structure doesn’t always translate perfectly into how patients feel day to day. Research on quality-of-life outcomes has found that while objective functional measures consistently improve after tracheobronchoplasty, self-reported quality of life doesn’t always follow in lockstep.20PubMed Central. Quality of life outcomes in tracheobronchomalacia surgery Some patients feel dramatically better; others improve on paper but remain symptomatic. This may partly reflect the complexity of the patients undergoing surgery, many of whom have coexisting lung disease, obesity, or other conditions that contribute independently to breathlessness and cough.
TBM in Children and 3D-Printed Splints
Pediatric TBM presents unique challenges. A baby’s airway is tiny, and standard adult-sized stents and surgical meshes don’t work. The airway also needs to grow, so any device has to accommodate that growth without requiring repeated surgeries to swap it out.
One of the more remarkable innovations in this space has been the development of custom 3D-printed external airway splints. Designed from CT scans of each individual patient’s airway, these bioresorbable splints are placed around the outside of the collapsing segment to hold it open. The material is engineered to slowly dissolve over a predetermined period, ideally giving the child’s airway enough time to strengthen on its own. Researchers implanted these devices in three infants with life-threatening TBM and reported successful outcomes.21PubMed Central. Mitigation of tracheobronchomalacia with 3D-printed personalized medical devices in pediatric patients The splints represent a genuine case of personalized medicine: each one is built to the exact anatomy of one patient’s airway. This technology is still evolving, but it highlights how differently TBM needs to be managed in growing children compared to adults.
Anesthesia Risks Worth Knowing About
If you have TBM and are facing any surgery requiring general anesthesia, this is something your anesthesiologist needs to know about ahead of time. Induction of general anesthesia can trigger acute airway collapse in people with TBM, presenting as a sudden inability to ventilate the patient that can rapidly become dangerous.22PubMed. Expiratory Central Airway Collapse in Adults: Anesthetic Implications (Part 1) The drugs used to induce anesthesia relax the muscles that normally provide some backup support to the airway wall, and positive pressure ventilation through a breathing tube changes airway dynamics in ways that can worsen collapse. An anesthesiologist who knows about the TBM can plan for it, using strategies like higher levels of positive end-expiratory pressure, adjusting the ventilator settings, or having a rigid bronchoscope ready. An anesthesiologist who is surprised by it has a crisis on their hands.
This risk applies to any procedure under general anesthesia, not just lung operations. If you’ve been diagnosed with TBM and need a hip replacement, gallbladder surgery, or even a dental procedure under general anesthesia, it’s worth making sure the information is prominently flagged in your medical record.
TBM in Dogs
TBM is not exclusively a human problem. Small-breed dogs, particularly Yorkshire Terriers, Pomeranians, and similar toy breeds, develop tracheomalacia at high rates. The disease in dogs is similar enough to human TBM that veterinary researchers have used canine patients to test new stent designs. One group developed a spiral airway stent tested in dogs with naturally occurring tracheomalacia, noting that the similarity between the disease in dogs and in human newborns makes dogs a useful model for refining devices that could eventually be used in pediatric patients.23PubMed. A new airway spiral stent designed to maintain airway architecture with an atraumatic removal after full epithelization-Research of feasibility and viability in canine patients with tracheomalacia The honking cough that small-breed dog owners sometimes chalk up to a “reverse sneeze” or a collapsing trachea is often the same fundamental process as what happens in a human with TBM: weakened cartilage letting the airway fold in on itself during exhalation. The cross-species overlap has opened a productive two-way street where veterinary innovations inform human device development and vice versa.