The vacuum bell device should be available as a non-surgical treatment option for selected people who have a pectus excavatum that is negatively affecting their physical and/or psychological wellbeing.
Multidisciplinary team decision making on the use of the vacuum bell device should take into account factors that may be associated with successful treatment outcomes: a younger age at treatment onset, a flexible chest wall, a smaller pre-treatment chest wall depth, patient motivation and acceptance of the treatment, and support from patients' caregivers.
There should be ongoing data collection on the effectiveness and safety of the vacuum bell device for people with pectus excavatum, to help inform optimal treatment protocols.
NHSScotland is required to consider the Scottish Health Technologies Group (SHTG) recommendations.
1. The Council acknowledged that the evidence base is limited, consisting mainly of retrospective studies which are more prone to bias. The Council agreed that, on balance, the body of evidence was sufficient to demonstrate that the VB device was likely to provide positive treatment outcomes in a selected group of patients, with few safety concerns.
2. The Council noted that the VB device is mainly offered to people with a mild PE as a conservative treatment option, when they would not normally be eligible for surgery and have no other treatment options. The VB device also has the potential to treat people with more moderate and severe PEs to reduce the need for surgery. The Council recognised the patient and service benefits from fewer surgeries.
3. A topic expert from the Scottish National Chest Wall Service described the patient pathway for people with a chest wall difference in NHSScotland. The first VB device was prescribed in NHSScotland in 2018, and since then nearly 400 have been fitted. The expert noted that most patients are aged between 5 and 16 years (median age 13). The service in Scotland includes physiotherapists, surgeons and psychologists. Consultations are provided remotely when feasible.
4. Following discussion with the topic expert, the Council noted that treatment with the VB device requires considerable commitment from patients and their parents or carers, and progress can be slow. The topic expert suggested that approximately 30% of people who start treatment with the VB device do not complete treatment. It was suggested that one way to improve adherence to treatment may be to use new technology, for example three dimensional (3D) photographs, so that the patient can better visualise the ongoing improvement in their chest wall difference and hopefully continue using the VB device. The topic expert advised that a key factor in a patient's decision to continue treatment is their own desire to correct the PE, which outweighs the influence of their parents or carers.
5. The Council heard from a patient organisation, Pectus Matters, who described the impact that a chest wall difference can have on individuals. The physical effects for some people are significant, particularly for those whose cardiorespiratory functions are impacted. Pectus Matters also stressed the substantial psychological consequences of PE for some people. Young people and adolescents are especially susceptible to negative feelings and self-consciousness about their bodies. The resulting impact on their desire to participate in regular activities should not be underestimated.
6. The Council considered the costs of the VB device, including the first line treatment costs of VB device use, conservative management and surgery. Economic modelling comparing costs and effectiveness was not possible because of a lack of relative outcomes data. The Council highlighted the low cost of the VB device and the potential for the device to be good value for money, even if only a small portion of patients benefit from using the device.
7. The Council noted the reusable nature of the VB device, and the potential environmental and cost benefits for the service. The topic expert advised that a VB device is currently likely to only be used by two patients sequentially, because regular use and cleaning causes deterioration in the silicone VB device material.
8. The Council noted the importance of ongoing data collection by the Scottish National Chest Wall Service, and subsequent review of these data. The Scottish service has an established patient pathway for people with chest wall differences, and considerable experience of prescribing the VB device. Ongoing data collection will help further our understanding of, for example, the patients most likely to benefit from treatment and optimal treatment protocols.
1. We identified 15 studies on the use of the VB device for people with PE. Thirteen were retrospective reviews of medical records, one was a prospective case series and one was a small randomised controlled trial (RCT). The studies were heterogeneous and prone to bias. The retrospective studies were mostly small, patients self-reported their daily wear time, and only people who completed the treatment were included in the final analyses. It is not clear from most of the studies if the treatment benefits that are reported are maintained in the longer term.
2. The largest (n=259) and most recent study (2024), from The Netherlands, reported that 86 out of 165 people who completed treatment with the VB device considered it a success (52.1%). Treatment was considered successful if patients, parents and a surgeon regarded the result as aesthetically pleasing.
3. Eleven of the 15 studies reported on the effectiveness of the VB device. The outcomes and how they were measured varied across the studies. In the four oldest studies the sternum was raised to a normal level in 13.5% to 31.5% of participants following treatment for up to 18 months. The remaining seven studies, published since 2018, reported a positive treatment outcome in approximately 20% to 50% of patients selected for treatment with the VB device.
4. Evidence suggests that a younger age at treatment onset (approximately ≤11 years) and a flexible chest wall are factors associated with successful treatment outcomes with the VB device. A smaller pre-treatment chest wall depth may also be associated with improved outcomes. One small, preliminary RCT (n=26) reported that treatment with the VB device may be further optimised if patients are also offered a standardised physiotherapy programme.
5. Three of the studies reported improved patient outcomes in people who wore the VB device for longer periods of time.
6. Optimal daily wear time cannot be determined from the available literature, and it is likely to differ depending on the age of the patient and the nature of their PE. Younger patients (aged ≤11 years) with a pliable chest wall may only require, and tolerate, shorter daily wear times. Two studies did not find evidence of improved outcomes with longer wear times (>60 minutes and >150 minutes), with one reporting that successful treatment outcomes were observed in several people who chose to wear the VB device for less than 60 minutes per day.
7. Five of the studies reported that total duration of treatment was associated with improved patient outcomes. Two studies suggested that use of the VB device should last at least 12 months, and another two studies reported that treatment should last 24 months. The optimal total duration of treatment is likely to vary according to the age of the patient and the nature of the PE.
8. The VB device may not be suitable for some people with asymmetrical PEs if this means the device cannot be attached to the chest wall (that is, a vacuum cannot be created). Breast development may also impede use of the VB device.
9. No safety concerns with the VB device were identified. Most people are able to tolerate treatment with the VB device, and the side effects and complications reported in the literature do not appear to be permanent or severe. Side effects noted in the literature include chest wall pain, back pain, skin irritation, haematoma, upper extremity paraesthesia, petechiae, thickening/darkening of the skin and blistering. As the VB device is typically used to treat PE in children and young people, support and supervision by a parent or carer is required.
10. A patient organisation told us how people can be negatively affected by a difference in their chest wall appearance, with some people experiencing significant psychological and/or physiological consequences. Some people with PE become self-conscious and withdraw from activities that they would otherwise enjoy. For people with more pronounced PEs, the compression in the chest can impede normal functions such as walking, exercising and swallowing. No literature was identified on the patient experience of using the VB device.
11. We estimated and compared the total costs of first line conservative management for PE (an initial in-clinic appointment followed by virtual appointments with a physiotherapist, quarterly for up to 18 months), surgical management and treatment with the VB device. The cost of treatment with the VB device (estimated between £468 and £503 per patient) was higher than the cost of conservative management alone (£192), but far lower than the costs of surgical management (£15,003 modified Ravitch procedure; £13,513 Nuss procedure).
12. We were unable to conduct a cost-effectiveness analysis comparing use of the VB device with usual care options because of a paucity of evidence for key parameters. Gaps in the evidence included efficacy of VB compared with usual care, and evidence relating to health-related quality of life following VB device or usual care.
What were we asked to look at?
We were asked to assess the vacuum bell (VB) device for people with a pectus excavatum (PE). We were asked to consider clinical effectiveness, cost effectiveness, safety and patient issues, and we were also asked to look at other factors such as optimal wear time, whether effectiveness varies depending on the severity of the PE, and the optimal age for treatment.
Why is this important?
PE can be apparent from birth, or it can appear in young people following a growth spurt, typically between ages 11 and 14 years. It is caused by an abnormal growth of the cartilage ribs that attach to the breastbone, resulting in the front of the chest having a sunken appearance. In people who are only mildly affected, there are no negative effects on physical health. In more severe cases, PE may influence heart and lung function. For some people, the appearance of a chest wall difference can impact on their quality of life and psychological wellbeing. PE is the most common congenital chest wall difference, and the incidence is reported to be up to 8 per 1,000 live births.
The VB device may be used by people with mild PEs to help improve quality of life, especially when no other treatment options are available. Use of the VB device may help reduce the need for surgery for people with a more pronounced PE, or may help to prevent a mild PE from becoming more severe during puberty.
