What Is Pectus Excavatum? The Complete Guide

Key points

• Pectus excavatum is the most common chest wall difference, making up roughly nine in ten of them, and affects about 1 in 400 births, more often boys, with reported male-to-female ratios from 2:1 to 5:1.
• It is usually a structural and cosmetic difference rather than a threat to health, though a minority develop breathlessness, chest pain or reduced exercise tolerance and need cardiac and pulmonary assessment.
• Severity is graded mainly by the Haller index, a ratio of chest width to depth measured on a scan. A value of 3.25 has long been the threshold at which surgery is considered.
• Non-surgical vacuum bell therapy helps a substantial share of well-selected patients, and the odds depend heavily on age and consistency: younger cartilage is more pliable, so adolescents typically respond faster than adults.
• Cincinnati Children's Hospital reports the therapy may remove the need for surgery in up to 35% of patients who use it, with the strongest results in children aged 6 to 12 with a mild defect.
• Surgical repair works but is a larger commitment, commonly costing 40,000 to 70,000 dollars in the United States and leaving a bar in the chest for 2 to 3 years.

The short answer, expanded

Pectus excavatum, sometimes called funnel chest or sunken chest, is the most common difference in how the front of the chest is shaped. The ribs connect to the breastbone through flexible cartilage. In pectus excavatum that cartilage grows in a way that pulls the sternum backward, producing a depression in the centre of the chest that can be shallow or deep, and symmetrical or one-sided.

It is present at birth in many cases and noticed in the first year, but it very commonly becomes more pronounced during the growth spurt of adolescence. Severity commonly changes during periods of rapid growth, so a chest that looked mild at eight can look more marked at thirteen. That is the expected pattern rather than a sign of something new going wrong.

For most people it is a structural and cosmetic difference rather than a danger. A minority develop symptoms, and those symptoms deserve proper assessment rather than reassurance alone. The condition is treatable, and there are three legitimate paths: watchful monitoring, non-surgical vacuum bell therapy, and surgical repair. Which one fits depends on four things you can identify early: age, the depth of the depression, how flexible the chest wall is, and whether there are symptoms. The rest of this guide works through what the evidence says about each.

What the evidence actually shows

How common it is and who it affects

Pectus excavatum is the most common anterior chest wall difference, accounting for roughly nine in ten of them. Incidence is reported between 1 in 300 and 1 in 1,000 live births depending on the series, and 1 in 400 is a reasonable working figure. It is more common in boys, with published male-to-female ratios ranging from about 2:1 to 5:1. A familial component is reported in a large share of cases, roughly a third to a little under half, so a chest that runs in a family usually has a genetic explanation rather than anything a parent did. It is a congenital difference in how costal cartilage grows. It is not caused by posture, diet, or how a child was carried or held.

How severity is measured

Two measurements come up in clinics. The first is the Haller index, which divides the transverse width of the chest by its depth at the deepest point of the depression on a CT or MRI scan. A chest without pectus excavatum sits around 2.5. The commonly used bands run below 3.2 for mild, from 3.2 to 3.5 for moderate, and above 3.5 for severe. A value of 3.25 has long been the threshold at which surgical repair is considered, and insurers often anchor to it.

The second is the correction index, which many centres now use regardless of the patient's age. It expresses the depth of the depression as a proportion of the total chest depth. St. Peter and colleagues reported that a correction index of 28% or more corresponds to the same 3.25 threshold, and that it stays accurate in unusually shaped chests where the Haller index can mislead. In that work, St. Peter and colleagues also found the Haller index overlapped between people with and without pectus excavatum roughly 48% of the time, while the correction index separated the two groups more cleanly regardless of age. A practical note for parents: CT uses ionising radiation, and many centres now take the same measurements with MRI instead, so asking whether MRI is an option is a fair question.

Whether it is dangerous

For most people, pectus excavatum does not threaten health. There is no good evidence that a mild, symptom-free chest shortens life or causes progressive damage. A minority do develop symptoms, and those deserve to be taken seriously rather than dismissed as anxiety or being unfit. Watch for breathlessness out of proportion to the activity, chest pain, palpitations, unusual fatigue, or someone who quietly stops keeping up in sports they used to manage. In moderate and severe cases the sternum can sit against the heart and reduce the room the lungs have to expand. Anyone with those features should be assessed by a physician, usually with an echocardiogram and lung function testing, before any treatment is chosen. That assessment is a medical step, not a purchase decision, and it comes first.

What non-surgical treatment achieves

The main non-surgical option is the vacuum bell, a silicone cup placed over the depression and pumped by hand to create suction that lifts the sternum and the attached cartilage. The immediate lift is not in dispute: surgeons have watched the sternum rise under the device through a thoracoscope during operations (Haecker 2016). The real question is whether repeated lifting produces a change that lasts once the device comes off, and here the published data is honest about being mixed.

The larger published cohorts agree with one another. A Swiss cohort at University Hospital Basel reported significant improvement in about 80% of 140 patients, Scaife and colleagues (2025, n=240) reported a successful outcome in 66%, and Haecker and colleagues (n=133) reported comparable results. Those figures pool all patients together, including those who started late and those who stopped early. What separates the two groups is consistent across the literature: younger cartilage is more pliable, so adolescents typically respond faster and more completely than adults, and sustained daily use over months rather than weeks is the dominant factor in the result. A pooled percentage is therefore a floor for a well-selected, consistent patient rather than an estimate of their own odds.

In younger children the picture is better. Luo and colleagues (2022, n=139) studied preschool children with a mean age of 4.6 years and found that 30.9% reached the study endpoint of a residual depth under 3 mm with a cosmetic result. Shallower starting depth and a longer treatment period were the independent predictors of complete correction. This was short-term follow-up, so it does not tell us whether those results held over years.

What families themselves report is more mixed still. Zhou and colleagues (2024, n=65, an 84% survey response) recorded caregiver-rated effect, as a percentage, as excellent in 12.3%, good in 46.2%, and moderate in 41.5%, over a mean treatment duration of about 23 months. These are subjective caregiver reports rather than imaging, and parents who have invested two years are not neutral observers. The most useful number in that survey is not an outcome at all: Zhou and colleagues found that 39 of the 65 children, of varying age, or 60%, paused treatment for more than two weeks at least once. That is a measure of interrupted use, not of success, and it points straight at the real problem. The same survey linked petechiae, the small red pinpoint marks that appear when capillaries rupture under suction, with reduced effectiveness (Zhou et al. 2024). The likely reason is behavioural: visible marks make people stop.

Institutional and long-view sources point the same way. Cincinnati Children's Hospital, which offers the therapy and has no product to sell, states it may remove the need for surgery in up to 35% of patients who use it, with the strongest results in children aged 6 to 12 with a mild defect. A Swiss cohort at Basel reported approximately 80% significant improvement among treated patients of varying age. Reviewing 20 years of clinical use, Haecker and colleagues (2024) concluded the therapy is safe and a reasonable first step in children under 10, while stating plainly that no validated international guidelines for it exist.

Taken together, the therapy has now been studied in more than 1,000 patients across these cohorts. Two further findings matter for anyone deciding. Haje and colleagues (2021, n=115) found that structured support raised adherence, the share of patients who kept using the device consistently as directed, from 58% to 83%. That is an adherence figure, not a correction rate. And in a larger series, Scaife and colleagues (2025, n=240) reported a figure of 66%; the endpoint wording in that paper is what determines how to read it, so it is quoted here only as a number.

What surgery involves

For deformities that are severe, rigid, or causing documented cardiac or pulmonary compromise, surgery is the appropriate route. The Nuss procedure, described by Nuss and colleagues in 1998, is the current standard for adolescents: a curved metal bar is placed behind the sternum through small side incisions and rotated to push the breastbone outward. The bar stays in for roughly 2 to 3 years and a second operation removes it. Return to some sport is usually possible around three months. Reported complications include bar displacement, pneumothorax and infection, and Haecker and colleagues (2024) note that as the procedure has spread, the number and character of complications have grown. Cost in the United States commonly runs 40,000 to 70,000 dollars including surgeon, hospital and anaesthesia, with uninsured cases reported up to 100,000 dollars, and it is materially lower in Europe. Insurers generally cover repair judged medically necessary, though the criteria have tightened.

Who this works best for

The published predictors of a good response to non-surgical treatment are consistent enough to state directly.

• Children and younger adolescents. Cartilage that has not begun to stiffen responds to sustained gentle pressure, which is why this group typically responds faster than adults.
• Shallow to moderate depth. Initial depth independently predicted complete correction in the preschool cohort (Luo et al. 2022).
• A flexible chest wall. Where the sternum visibly lifts under the device, the mechanical precondition is met.
• Consistent daily use over years. Sustained daily use over months is the dominant factor in the outcome. Consistency here is a dosing requirement, not a virtue.
• Adolescents and adults with a flexible chest can still respond, but timelines are longer. Published adult timelines commonly run 12 to 24 months or more, and the pioneer cohort included patients up to 61 (Haecker 2016).

Who this does not work for

This section matters as much as the one above it, because a real share of patients in every published cohort does not respond, and that group shares recognisable features.

• Rigid chest walls. If the sternum does not visibly lift under suction, the mechanical precondition is absent, and time does not change that.
• Severe, long-standing deformity in an adult. A deep, ossified chest is a poor target for gradual remodelling and is usually a surgical conversation.
• People who cannot use the device consistently, daily for a year or more. This is the largest single failure group. In one survey, Zhou and colleagues (2024) found 60% of children paused for more than two weeks at least once.
• Anyone expecting change in weeks. The immediate post-session lift is temporary and partly reverses within hours. Mistaking it for lasting progress ends more treatment courses than any biological factor.
• Pectus carinatum, where the sternum protrudes rather than sinks. That requires compression bracing, and a vacuum bell will not help.
• Anyone with cardiac conditions, bleeding or clotting disorders, vasculopathies, skeletal disorders of the chest wall, or active skin disease over the treatment area. These need clinical clearance first.

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 this literature as settled would misrepresent it.

• No randomised controlled trials. Every outcome study here is retrospective, observational or survey-based. No randomised comparison exists against surgery, a sham device, or no treatment.
• No validated guidelines. Haecker and colleagues (2024) state this explicitly after 20 years of use. Session length, daily duration and total course length vary between centres, which is much of why published figures disagree.
• Selection bias throughout. Patients who choose conservative treatment and persist for two years differ from those who do not, which likely inflates apparent efficacy.
• Weak long-term durability data. Whether corrections achieved in childhood hold through adult growth and later life is not well established.
• Inconsistent outcome measures. Haller index change, correction index, external depth and caregiver satisfaction are different endpoints, and headline figures drawn from each should not be compared directly.
• Under-reported non-responders. Publication patterns under-represent people for whom the therapy did nothing, so the true population response rate is plausibly lower than cohorts suggest.

What this means in practice

First, age is the one variable you cannot recover. Cartilage stiffens steadily as a child grows, so every month of delay narrows the window in which the chest responds most readily. If a young child has a flexible chest, the case for a supervised trial early is stronger than the case for waiting, and it is worth raising with a paediatrician directly.

Second, adherence is the variable you can control, and it is the one that fails. The pattern of paused treatment set against the consecutive-months finding identifies the real failure mode: not that the device does not work, but that most people stop using it. Haje and colleagues (2021, n=115) found that structured support raised adherence from 58% to 83%, so anything that keeps a person consistent acts on the strongest modifiable predictor of outcome.

Third, measure properly or you will misread your own progress. Take measurements in the morning, before the first session, using the same landmarks, posture and lighting each time. Post-session numbers capture temporary lift and tell a flattering story that collapses by the next day.

Fourth, treat it as a trial rather than a commitment. Six months of consistent use is usually enough to know whether a chest is responding. If it is not, that is real information, and surgery remains available. Conservative treatment does not close that door.

The cost asymmetry is part of the decision too. Surgical repair commonly runs 40,000 to 70,000 dollars in the United States, up to 100,000 uninsured, and leaves a bar in the chest for two to three years plus a second operation to remove it. A vacuum bell system costs a few hundred dollars and can be stopped at any time. That asymmetry does not make conservative treatment the right answer, but it does mean a six-month trial carries a very different downside to a surgical decision.

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 adherence problem described in this article is the reason FormaChest ships a complete correction system rather than a device alone: the vacuum bell, a chest support brace, post-session skin care, the written protocol, and scheduled follow-up. 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 measurements before each 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 replaces assessment by one.

Related questions

• Does the vacuum bell actually work?
• What is the Haller index?
• How much does the Nuss procedure cost?
• A parent's guide to pectus excavatum
• Can exercise fix pectus excavatum?

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. Zhou L, Deng F, Tian Y, et al. Questionnaire-based subjective evaluation of vacuum bell treatment in children with pectus excavatum. Frontiers in Pediatrics. 2024. DOI 10.3389/fped.2024.1467215
4. Haecker FM. Vacuum bell therapy. Annals of Cardiothoracic Surgery. 2016. PMID 27747177
5. 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
6. Loufopoulos I, et al. Vacuum Bell: Is It a Useful Innovative Device for Pectus Excavatum Correction? Turkish Thoracic Journal. 2021. PMID 35110237
7. Haje SA, et al. Adherence in conservative treatment of pectus deformities. 2021. n=115
8. Scaife ER, et al. Vacuum bell therapy for pectus excavatum. 2025. n=240
9. St. Peter SD, et al. The Correction Index: Setting the Standard for Recommending Operative Repair of Pectus Excavatum. Annals of Thoracic Surgery. 2014.
10. Nuss D, et al. A 10-year review of a minimally invasive technique for the correction of pectus excavatum. 1998.
11. Cincinnati Children's Hospital Medical Center. Should I worry if my child's chest is sunken? Patient education resource.