Ex vivo laser thermoplasty of whole costal cartilages

Abstract

Background and objective: To examine the possibilities of laser thermoplasty of whole costal cartilages for correction the human congenital chest wall deformities.

Study design/materials and methods: Ex vivo the samples of porcine costal cartilages were heated with lasers of differing wavelengths, including a 0.97-μm diode laser, a 1.56-μm erbium-doped quartz fiber laser, and a 1.68-μm fiber Raman laser. The dynamics of the temperature fields and the degradation of collagen in the laser-affected regions of samples were determined by using, respectively, thermometry, trypsin treatment, and light microscopy. Ex vivo the whole mechanically deformed costal cartilages of pigs were treated by laser radiation with wavelength 1.68-μm. The changes of cartilage shape were recorded at certain intervals over a 24-hour period by photographing them in a fixed position with a digital camera.

Results: Treatment of costal cartilage samples from 5 to 11 mm in thickness by laser radiation with 0.97, 1.56, and 1.68 μm wavelengths showed that the 1.68-μm radiation could produce the necessary nonuniform bulk heating of the exposed sample. The altered shape of costal cartilage proved to remain stable after treatment when the laser irradiation settings used provided for the heating of a broad region within the tissue to temperatures about 80°C.

Conclusion: This study demonstrates the possibilities of laser thermoplasty of whole costal cartilages for treatment of human congenital chest wall deformities. The development of novel approaches based on laser cartilage engineering techniques will enable to treat the human congenital chest wall deformities.

Keywords: chest wall deformities; child funnel chest; laser reshaping; pectus carinatum and excavatum in children; stress relaxation in cartilage.