title: Laser reshaping of costal cartilage for transplantation.
abstract: OBJECTIVE
  Laser reshaping of cartilage is a new effective and safe technique for correction of nasal septum and ear deformities. Costal cartilage is a most suitable natural material for transplantation. The problem is to obtain stable proper shape of cartilage implants. The objective of this article is to study reshaping of porcine costal cartilage for larynx stenosis surgery using Erbium glass fiber laser.
  
  
  METHODS
  Porcine cartilage plates 3 mm in thickness were mechanically curved and irradiated (1) on one side (stretched or compressed) and (2) on both sides with different sequence. Irradiation was performed using a 1.56 µm laser with power varied from 1 to 2.5 W, exposure time from 5 to 20 seconds, spot diameter of 2.5 mm, pulse duration of 500 milliseconds, pulse repetition rate of 1.4 Hz. For each laser setting, stable curvature radius was measured during 24 hours after the experiment. Irradiated samples were analyzed by means of differential scanning calorimerty (DSC) to reveal the collagen denaturation degree.
  
  
  RESULTS
  The optimum laser setting for stable reshaping of costal cartilage without visual thermal damage of cartilage matrix was established: laser power of 2.2 W, exposure time of 6 seconds. Nonlinear thermomechanical behavior of cartilage in the course of its laser reshaping is experimentally revealed. The influence of irradiation sequence on the curvature radius of cartilage implant is found for the first time. It is shown that (1) it is possible to use laser reshaping technique for making stable proper shape of costal cartilage, and (2) primary irradiation of compressed side followed with an irradiation of stretched side is more effective than reverse sequence of laser treatment. DSC analysis showed that thermal effect of irradiated specimens (2.58-3.79 J/g) was slightly lower that that for intact cartilage specimens and considerably lower than that for denaturation of collagen (65 ± 5 J/g).
  
  
  CONCLUSIONS
  It is possible to use laser reshaping technique for preparation of stable cartilage implants. Nonlinear thermomechanical behavior of cartilage is experimentally revealed. The influence of irradiation sequence on curvature radius of cartilage grafts is established for the first time.
authors.affiliation: Institute on Laser & Information Technologies, Russian Academy of Sciences, Troitsk 142190, Russia. baumolga@gmail.com
authors.forename: Olga I
authors.initials: OI
authors.lastname: Baum
authors.forename: Yulia M
authors.initials: YM
authors.lastname: Soshnikova
authors.forename: Emil N
authors.initials: EN
authors.lastname: Sobol
authors.forename: Andrey Ya
authors.initials: AY
authors.lastname: Korneychuk
authors.forename: Mariya V
authors.initials: MV
authors.lastname: Obrezkova
authors.forename: Valeriy M
authors.initials: VM
authors.lastname: Svistushkin
authors.forename: Oxana K
authors.initials: OK
authors.lastname: Timofeeva
authors.forename: Valeriy V
authors.initials: VV
authors.lastname: Lunin
mesh_terms: D000818:Animals; D002356:Cartilage / Q000601:surgery* / Q000637:transplantation*; D053685:Laser Therapy; D012272:Ribs / Q000601:surgery* / Q000637:transplantation*; D013552:Swine