How the Chest Wall Responds to Vacuum Bell Therapy

A vacuum bell places a silicone suction cup over the sunken chest and draws gentle negative pressure that lifts the sternum and the attached rib cartilage. That immediate lift has been confirmed thoracoscopically during surgery (Haecker 2016). Whether repeated lifting produces lasting change depends on cartilage flexibility, which is greater in younger patients and declines with age.

Key points

• The immediate mechanism is not disputed. Elevation of the sternum and attached rib cartilage under the device has been observed directly through a thoracoscope during minimally invasive surgery (Haecker 2016, approximately 450 patients).
• The device works by sustained gentle negative pressure over the deepest point. The protocol traced to the modern device is a minimum of 30 minutes twice daily, extending to several hours daily thereafter (Haecker 2016).
• Lasting change is attributed to gradual reshaping of pliable costal cartilage, which is more flexible in younger patients and stiffens with age. That is why adolescents typically respond faster and more completely than adults.
• Shallower initial depth and a longer treatment period independently predicted complete correction in preschool children (Luo et al. 2022, n=139).
• The durable-remodelling explanation remains a working hypothesis, not a proven pathway. After 20 years of clinical use, no validated guidelines for the therapy exist (Haecker et al. 2024).

The short answer, expanded

Pectus excavatum is a chest wall in which the sternum, the flat bone down the centre of the chest, and the costal cartilage that joins the ribs to it sit lower than the surrounding ribs, producing an indentation. A vacuum bell is a silicone dome and a hand pump. Pumping air out of the dome lowers the pressure inside it, and the resulting suction pulls the sunken area outward while the device is worn.

The chest wall responds in two distinct ways, and they should not be confused. The first is immediate and mechanical: the sternum and the attached cartilage lift under the suction, then settle back after the device comes off. The second is the proposed longer-term change, in which repeated daily lifting is thought to gradually reshape the cartilage so that some of the correction remains. The first response is directly observed and not in dispute. The second is inferred from outcome data and from what is known about cartilage, and it is where the honest uncertainty in this therapy lives.

What the evidence actually shows

The immediate mechanical response

The clearest single piece of mechanism evidence comes from surgery. During minimally invasive repair, surgeons place a camera inside the chest, and while the vacuum bell is applied to the outside they can watch what moves. Haecker (2016), reviewing a cohort of approximately 450 patients aged 2 to 61, reported that the sternum and rib cartilage rise under the device, confirmed thoracoscopically during the operation. This is the part of the mechanism that is settled. Negative pressure over the indentation produces real, visible elevation of the chest wall in that moment.

That elevation is not the same as a lasting result. The immediate lift is temporary and partially reverses within hours of removing the device. Mistaking the post-session lift for durable progress is one of the most common errors patients make, and it is addressed further below.

Why age changes the response

Costal cartilage is more pliable in younger patients and stiffens as the skeleton matures. A therapy that works by sustained gentle deformation depends on that pliability, so the same daily suction acts on a more responsive tissue in a child than in an adult. The outcome literature matches this biology closely. Younger patients respond faster and more completely than adults, and patients who begin later change less. Sustained daily use over months, rather than weeks, carries a similar weight. Age and time, the two variables the mechanism predicts should matter, are the two the literature singles out. A Swiss cohort at University Hospital Basel reported significant improvement in about 80% of 140 patients, and Scaife and colleagues (2025, n=240) reported a successful outcome in 66%.

What the youngest chests show

Luo and colleagues (2022, n=139) studied preschool children with a mean age of 4.6 years in Frontiers in Pediatrics, tracking chest depth with a three-dimensional scanner. Two factors independently predicted complete correction: shallower initial depth (odds ratio 0.69) and a longer treatment period (odds ratio 1.58). In plain terms, a shallower chase and more time on the device did better. This was short-term follow-up, so it describes how the chest wall responds during treatment, not whether that response holds for years.

The remodelling hypothesis and its limits

The word often attached to the lasting response is remodelling: the idea that repeated lifting slowly changes the shape of the cartilage itself rather than just moving it while the device is on. This is a reasonable explanation and it fits both the immediate observation and the age and time findings. It is not, however, a proven mechanism. No study cited here has imaged cartilage before and after therapy to show the tissue reshaping directly, and Haecker and colleagues (2024), after 20 years of clinical application, state plainly that no validated guidelines for the therapy exist. Treat durable remodelling as the current best explanation for the outcome data, not as an established fact.

How much of the chest actually changes

A Swiss cohort in Basel reported significant improvement in approximately 80% of patients (Basel cohort, approximately 140 patients). As with every cohort here, that figure describes selected and consistent users, not the general population, so read it as what a motivated group achieved rather than a rate to expect. The engineer who developed the modern device had pectus excavatum himself and reshaped his own chest over roughly two and a half years of daily use (Klobe cohort). Cincinnati Children's Hospital, a major paediatric centre with no product to sell, reports the strongest results in children aged 6 to 12 with a mild defect. The design of that device received FDA clearance in 2012 and carries CE certification, which applies to the device design and not to any single seller.

Who this works best for

The mechanism predicts a recognisable group in whom the chest wall responds best, and the outcome data agrees.

• Children and younger adolescents. Cartilage that has not begun to stiffen deforms most readily under sustained suction, which is why this group typically responds faster than adults.
• Shallower deformities. Shallower initial depth independently predicted complete correction in the preschool cohort (Luo et al. 2022, n=139).
• A flexible chest wall. Where the sternum visibly lifts under the device, the mechanical precondition for a response is present.
• People who can stay consistent for years. Sustained daily use over months is the dominant factor in the outcome. Consistency here is a dosing requirement, not a virtue.

Who this does not work for

The same mechanism that explains who responds also names who does not, and this section matters more than the one above it.

• Rigid, ossified chests. If the sternum does not visibly lift under suction, the tissue no longer has the pliability the mechanism depends on, and more time does not supply it. This is common in deep, long-standing adult deformity, which is usually a surgical conversation.
• Severe deformity in an adult. A deep, mature chest is a poor target for a device that works by gradual reshaping of flexible cartilage. The honest advice is a proper surgical assessment rather than a purchase.
• Anyone expecting change in weeks. The immediate lift after a session is temporary and partially reverses within hours (Haecker 2016). The durable response, if it comes, is measured in years.
• Pectus carinatum. A protruding sternum is the opposite deformity and needs compression bracing, not suction. A vacuum bell is not indicated and will not help.

Anyone with breathlessness disproportionate to exertion, palpitations, chest pain or reduced exercise tolerance should be assessed by a physician before starting, because those symptoms change the calculation and are not something a device purchase should precede. Cardiac conditions, bleeding disorders and active skin disease over the treatment area are specific contraindications that need clinical clearance first.

What this means in practice

Three things follow from how the chest wall actually responds.

Judge the durable response, not the session lift. Because the immediate elevation reverses within hours, measuring straight after a session tells a flattering story that collapses by the next morning. Measure in the morning, before the first session, using the same landmarks and posture each time, and compare across months rather than from one week to the next.

Age is the variable you cannot get back. The pliability the mechanism relies on declines steadily with growth, so a chest at 9 or 10 responds more readily than the same chest a few years later. If a young child has a flexible chest, the case for starting a conservative trial early is stronger than the case for watchful waiting, and it is worth raising with a paediatrician directly.

The downside of a trial is small next to the alternative. Surgical repair in the United States commonly runs 40,000 to 70,000 dollars, with uninsured cases reported up to 100,000, and involves a bar in the chest for two to three years plus a second operation to remove it. A vacuum bell trial costs a few hundred dollars and can be stopped at any time. A six-month trial is usually enough to see whether a chest is responding, and stopping closes no surgical door.

Not sure whether this applies to you?

The two questions this article cannot answer for you are whether your own chest is a reasonable candidate, and which device size fits it. Both depend on measurements only you can take.

The FormaChest assessment takes about four minutes. It screens your situation against the variables the research identifies as predictive (age, depth of the indentation, chest flexibility and symptoms) and returns an honest read on whether conservative treatment is a reasonable first step. That includes telling you when the answer is to see a surgeon first, which it does for roughly the situations described in the section above.

It also returns a vacuum bell size recommendation based on your own measurements, at no cost.

Sizing is normally not free or simple in this category. The usual process is to email photographs of your bare chest to a company and wait for a reply, or to print paper templates and tape them to yourself, with the manufacturer warning that self-measurement may produce the wrong model. The assessment asks for numbers you can take alone with a ruler. No photographs, no email exchange, no deposit.

Take the free assessment →

What the research does not tell us

Presenting the mechanism as settled would misrepresent it, and the gaps are specific.

The remodelling pathway is inferred, not imaged. No study cited here has shown costal cartilage reshaping directly before and after therapy. The durable response is deduced from outcome data and from the known behaviour of cartilage, which is a reasonable basis but not a demonstrated mechanism.

No randomised trials. Every study here is retrospective, observational or survey-based. There is no randomised comparison against surgery, against a sham device, or against no treatment, so effect sizes should be read as associations.

No validated guidelines. Haecker and colleagues (2024) state this directly after 20 years of use. Daily hours, session length, suction pressure and total course length vary between centres, which is a large part of why reported results disagree.

Weak durability data. Short-term cohorts such as Luo (2022, n=139) show a chest can respond during treatment, but whether corrections hold through later growth and into adulthood is not well established. Adherence, not the device, drives much of the variation. Zhou and colleagues (2024, n=65) found that 60% of children paused use for more than two weeks at least once, which breaks the consistent daily pressure the mechanism requires.

About this guide This article is published by FormaChest, a European manufacturer of vacuum bell correction systems, registered in Romania as AUGUMENTUM SRL. We make the device described above, and every figure quoted is cited to its source so you can verify it independently. The mechanism described in this article depends on sustained, consistent use, which is the reason FormaChest ships the bell, brace and gel together rather than a device alone: the vacuum bell, a chest support brace, post-session skin care, the written protocol, and scheduled follow-up. Together, the bell, brace and gel are $461.40 in the men's line and $491.40 in the women's line, where every competitor in this category sells the device by itself. See what is included →Tomas Titus is the founder of FormaChest (AUGUMENTUM SRL, Craiova, Romania). He had pectus excavatum and corrected it without surgery, documenting his own vacuum bell treatment on camera, taking each measurement before a session rather than after. His chest depth went from 25mm to 4mm. That is one person's result at 19; published adult timelines run 12 to 24 months and results vary. He is not a clinician, and nothing in this article is a substitute for assessment by one.

Related questions

• What is pectus excavatum?
• Does the vacuum bell actually work?
• What is the Haller index?
• How long does vacuum bell therapy take?

References

1. Scaife ER, et al. Vacuum bell therapy for pectus excavatum. 2025. n=240
2. Luo D, Cheng K, Yuan M, Xu C, He T. Efficacy and determinants of vacuum bell treatment in preschool children with pectus excavatum. Frontiers in Pediatrics. 2022. PMID 36313864
3. Haecker FM. Vacuum bell therapy. Annals of Cardiothoracic Surgery. 2016. PMID 27747177
4. Haecker FM, et al. 20 years clinical application of the vacuum bell for conservative treatment of pectus excavatum. Journal of Thoracic Disease. 2024. PMID 39268139
5. Loufopoulos I, Karagiannidis IG, Lampridis S, Mitsos S, Panagiotopoulos N. Vacuum Bell: Is It a Useful Innovative Device for Pectus Excavatum Correction? Turkish Thoracic Journal. 2021. PMID 35110237
6. Zhou L, Deng F, Tian Y, et al. Questionnaire-based subjective evaluation of factors influencing vacuum bell treatment effectiveness in children with pectus excavatum. Frontiers in Pediatrics. 2024. DOI 10.3389/fped.2024.1467215
7. Cincinnati Children's Hospital Medical Center. Vacuum bell therapy for pectus excavatum. Patient education resource.

This article is for information only and is not medical advice. Pectus excavatum should be diagnosed and assessed by a qualified physician. If you have chest pain, breathlessness, palpitations or reduced exercise tolerance, seek medical assessment before beginning any treatment.

Last reviewed: July 2026.