Discussion

Nowadays information on new therapeutic modalities circulates not only among surgeons and paediatricians but also rapidly among patients. In particular, patients who refused operative treatment by previously available procedures, now appear at the outpatient clinic and request to be considered for the new method. The vacuum method was used as early as 1910 by Lange [8] for elevating the sternum, but has not been previously applicated in a large number of patients, and long-term results are not reported. The vacuum bell used in our patients group was developed by an engineer, who himself suffered from PE (Klobe, http://www.trichterbrust.de). Long-term evidence of persistent effects of the treatment modality are not yet available, since the method has only been used for a maximum of 2 years. However, initial results proved dramatic, and the acceptance and compliance of patients seem to be good. In many cases of PE, the degree of pectus deformity does not immediately warrant surgery, yet patients may benefit from some type of nonsurgical treatment. Other patients are disinclined to undergo surgery because of possible complications after surgery, because of the pain associated with postoperative recovery and the risk of imperfect results. Thus, the introduction of the vacuum bell for conservative treatment of PE has generated much interest among patients with PE, despite of the lack so far of long-term results of the method.

The success of a therapeutic procedure not only requires a good technique, but also depends on a appropriate indication. In our study, patients, who presented with symmetric and mild PE, seemed to show a more successful outcome than those with asymmetric and deep PE. The application of the vacuum bell was well tolerated by both paediatric and adult patients. All patients except one were satisfied with the use of the vacuum bell, although objectively assessed improvement of PE varied between the individuals. All our patients were recommended to carry on undertaking sports and physiotherapy, so that the accompanying improvement of body control was an important factor in outcome. The participation of patients themselves in the ‘active’ treatment of PE clearly increases motivation to maintain therapy. The manufacturers instructions and our treatment protocol recommended application of the device twice daily for 30 min each. However, the definitive duration and length of use was determined by the individual patient and the parents, respectively. As demonstrated in the CT-scan (Bahr, http://www.trichterbrust.de), the force of the vacuum bell is strong enough to deform the chest within minutes. Therefore, especially in children younger than 10 years of age the application of the vacuum bell has to be performed carefully and should be supervised by an adult.

When creating the vacuum, the elevation of the sternum is obvious and persists for a distinct period of time. Therefore, the vacuum cup may also be useful in reducing the risk of injury to the heart during the MIRPE procedure, where the riskiest step of the procedure is the advancement of the introducer between the heart and sternum. Since the manufacturer of the device has not yet a license to sterilise the vacuum bell, this additional use has to be considered as a clinical trial. In accordance with our hospital hygienist, we applied the vacuum bell during the MIRPE procedure in a few patients with good experience. In addition, the vacuum bell may be useful in a way of ‘pretreatment’ to surgery. Since none of the 34 patients asked for the MIRPE procedure, we could not confirm this hypothesis at the moment.

In conclusion, the vacuum bell may allow some patients with PE to avoid surgery. Especially patients with symmetric and mild PE may benefit from this procedure. However, the time of follow-up in our series is too short to confirm this with any certainty. Additionally, the intraoperative use of the vacuum bell during the MIRPE may facilitate the introduction of the pectus bar. This must be evaluated by further studies. In any case, the method seems to be a valuable adjunct therapy in the treatment of PE.