Assessment of children with pectus excavatum without surgical correction

Unsophisticated assessment of the cardiopulmonary function in patients with pectus excavatum using the six minute walk test

BACKGROUND

We explored whether the maximum predicted walking distance, assessed with six-minute walk test (6MWT) and reflecting submaximal functional exercise capacity, is decreased among patients with pectus excavatum (PEX).

METHODS

This study comprised a retrospective analysis of patients with PEX who underwent a 6MWT for the assessment of functional capacity. The maximum distance walked was recorded and compared to reference values established for different populations, including a young and healthy South American population.

RESULTS

We included 43 patients with PEX who underwent 6MWT. The mean age was 17.8 ± 6.7 years. The mean maximum distance walked was significantly lower than the predicted distance (600.8 ± 67.6 metres vs. 729.8 ± 67.5 metres, p < 0.0001). Using the Enright reference equation including an older reference population, the mean negative difference was higher (PEX patients walked 190.4 ± 78.4 metres less than predicted, p < 0.0001). We also applied the Li et al. reference equation accounting for sex among other variables, detecting a decreased walked distance compared to the gender-adjusted predicted distance (PEX patients walked a mean 222.4 ± 87.4 metres less than predicted, p < 0.0001). Using the Ulrich et al. equation, PEX patients walked a mean 114.2 ± 85.1 metres less than predicted (p < 0.0001). Although of uncertain clinical relevance, there was a significant decrease in the mean oxygen saturation after exercise (baseline 97.4 ± 1.2%, vs. final 96.4 ± 2.1%, p = 0.006).

CONCLUSIONS

In this study, we identified a significant reduction in the maximum walked distance among patients with PEX compared to the predicted distance, thus potentially emerging as an unsophisticated means to evaluate and quantify functional exercise capacity.

[Funnel Chest Corrective Surgery with the Aid of a 3D Reconstruction of the Bony Thorax for Preoperative Adjustment of the Metal Bar]

BACKGROUND

Funnel chest is a congenital deformity of the thorax in which the sternum and the adjacent ribs form a funnel towards the spine. As the pathogenesis has not yet been clearly clarified, there are different therapeutic approaches. These range from conservative measures and minimally invasive surgery to open corrective surgery. The patients suffer from aesthetic impairment, as well as cardiopulmonary restrictions due to the narrowing of the mediastinal space. The indication for funnel chest correction surgery is therefore justified by functional and aesthetic reasons.

PATIENTS

We report a 23-year-old male patient who presented with subjectively impairing and objectively moderate funnel chest. A chest CT scan was performed preoperatively. The sternovertebral distance was 8 cm, the transverse thoracic diameter 28,9 cm (Haller's index 3.6). The preoperative pulmonary function test showed a slight restriction, the otherwise healthy patient described shortness of breath with greater exertion. The indication for funnel chest correction surgery was made. The operation was performed using a combined surgical technique: sternotomy and cartilage wedge resection according to Brunner/Grob and implantation of a metal bar without lateral antirotation plate. The most time-consuming step of the operation is the intraoperative adjustment of the metal bar. Therefore, in advance of the operation, we used a 3D printer to prepare a 3D reconstruction of the bony thorax with the help of the thorax CT scan. The metal bar was then bent and fitted to the thorax print and implanted during surgery. This allowed us to shorten the operation time by at least 15 min.

RESULTS

The postoperative follow-up examinations showed a clearly erect funnel and a satisfactory aesthetic result. The metal bar explantation took place, as planned, 7 months after implantation. The postoperative CT scan now showed a Haller's index of 3.25, the pulmonary function test showed improved results. Subjectively, the patient was always symptom-free.

CONCLUSION

The preparation of medical implants with 3D patient models as templates helps to save operation time. The practicability has not yet been established, as the creation of a 3D model of the bony thorax is associated with a different approach. With the increasing digitisation of the medical world, however, it is conceivable that the creation of digital and real 3D models will become easier and cheaper in the future.