Biomechanics of Operation to Correct a Pectus Excavatum Deformity

The algorithm and program implementation of numerical simulation of the process of surgical correction ofpectus excavatum deformity are set forth. A case ofsymmetrical chest deformation of a male patient is considered. The construction of a threedimensional finite-element model of the patient thorax and the simulation of a process of the low invasive correction of the funnel chest deformation (Nuss procedure for pectus excavatum) are performed using the modern program complexes. The constructed model includes ribs, sternum, costal cartilages, vertebras, intervertebral disks, and correcting bars. Joints of costal cartilages with ribs and sternum as well as joints of ribs with vertebras were assumed to be immobile. Taking into account the interaction between the bars and the sternum has been implemented by means of creation of the contact surface out of three-dimensional contact finite elements. The analysis of stress and strain state of the chest and the correcting bars is performed after the operation. The adequacy of these results is established on the basis of processing of the experimental data available.

References

[1] Kuz’michev V.A. Informatsionnyy resurs o rekonstruktivnoy i esteticheskoy khirurgii grudnoy kletki [Information resource about reconstructive and cosmetic surgery of the chest]. Available at: http://www.pectusexcavatum.ru (accessed 01.04.2013).

[2] Nuss D., Kelly R.E., Croitoru D.P., Katz M.E. A 10-year rewiew of minimally invasive technique to the correction of pectus excavatum. J. Pediatr. Surg., 1998, no. 33, pp. 545-552.

[3] Kurutz M. Finite element modelling of human lumbar spine. In: Moratal D. Finite element analysis. Ch. 9. InTech Publ., 2010, pp. 209-236. Available at: http://www.intechopen.com/books/finite-element-analysis/finite-element-modelling-of-human-lumbar-spine (accessed 01.04.2013).

[4] Pei Yeh Chang, Zhen-Yu Hsu, Da-Pan Chen, Jin-Yao Lai, Chao-Jan Wang. Preliminary analysis of the forces on the thoracic cage of patients with pectus excavatum after the Nuss procedure. Clin. Biomech., 2008, no. 23, pp. 881-885.

[5] Vaziri A., Nayeb-Hashemi H., Akhavan-Tafti B. Computational model of rib movement and its application in studying the effects of the age-related thoracic cage calcification on respiratory system. Comput. Methods Biomech. Biomed. Eng., 2010, vol. 13, no. 2, pp. 257-264.

[6] Nagasao T., Miуamoto J., Tamaki T., Ichihara K., Jiang H., Taguchi T. Stress distribution on the thorax after the Nuss procedure for pectus excavatum results in different patterns between adult and child patients. J. Thorac. Cardiovasc. Surg., 2007, no. 134, pp. 1502-1507.

[7] Nagasao T., Noguchi M., Miyamoto J., Jiang H., Ding W., Shimizu Y. Dynamic effect of the Nuss procedure on the spine in asymmetric pectus excavatum. J. Thorac. Cardiovasc. Surg., 2010, no. 140, pp. 1294-1299.

[8] Weber P.G., Huemmer H.P., Reingruber B. Forces to be overcome in correction of pectus excavatum. J. Thorac. Cardiovasc. Surg., 2006, no. 132, pp. 1369-1373.

[9] Niedbala A., Adams M., Boswell W.C., Considine J.M. Acquired thoracic scoliosis following minimally invasive repair of pectus excavatum. Am. Surg., 2003, no. 69, pp. 530-533.