An experimental setup with a laser fiber optic probe has been developed, and the vibration dynamics of the vocal folds (VFs) in the larynx of rabbits have been studied. VF vibrations were excited by a variable pressure air stream. We found that, at an air flow pressure of 50 to 60 mm Hg, VFs generate a white vibration noise in the frequency range of 100 Hz to 10 kHz. The spectrum of excited vibration frequencies becomes narrower when the air flow pressure decreases from 10 to 20 mm Hg, and three discrete lower fundamental frequencies of intrinsic mechanical vibrations of individual VFs are excited at about 360, 750, and 1100 Hz, simultaneously with narrow peaks in the high-frequency region at about 3, 6, and 8 kHz, respectively. The characteristic discrete vibration frequencies of VFs are most efficiently excited near the air flow exhaustion at a pressure of 1 to 5 mm Hg. We detected a difference in the fundamental frequencies of the excited vibrations between intact VF and those treated for a scar defect in one of the VFs. The frequencies of the lowest intrinsic excited modes of the treated VF are slightly higher compared with untreated (intact) VF. The increase in the vibration frequencies may be explained by the growth of VF’s stiffness related to the formation of scar tissue. The mentioned frequency difference was registered with confidence and may serve as a basis for a mildly invasive instrumental diagnostics in the therapy of VF disorders as an aid to a traditional examination and subjective assessment of VF states.
Cartilage is the best nature material for transplantation. Laser reshaping of cartilage allows obtaining any desirable shape of the implant. This work continues the interdisciplinary studies on laser-induced development of stable costal cartilage implants, the most promising biological object for the manufacture of implants (grafts) used in otolaryngology and maxillofacial surgery, in particular, in recovering tracheal defects for the treatment of larynx stenosis. We used 1560 nm fiber laser with feedback control system measuring tissue temperature in the course of laser irradiation.
The thermomechanical IR-laser effect on reshaping process for ENT is studied. The possibility and conditions of the laser reshaping of costal cartilage for stable human implants are investigated. The causes of nonlinear thermomechanical behavior of cartilage and its influence on controlled reshaping and stability of costal cartilage for ENT are discussed. Clinical trials for 5 patients with one and a half year follow-up observation demonstrate stable positive results.
As cartilage is an ideal natural material for transplantation, its use in the ENT surgery is limited by a difficulty to get
proper shape of cartilage implants. Aim of the work is to make ring-shaped cartilage implants, to check their stability
after laser reshaping and to perform transplantation into rabbits in vivo. We experimented with costal cartilages of 1-2
mm in thickness obtained from 3rd and 4rd ribs of a rabbit. 1.56 μm laser (Arcuo Medical Inc.) was used for cartilage
reshaping. The laser settings were established taking into account anisotropy of cartilage structure for different
orientation of the implants. The reshaped cartilage implants were surgically sewn to rib cartilages of the other rabbits.
The rabbits were slaughtered in 3.5-4 months after surgery. The results have shown that (1) all reshaped implants kept
circular form, and (2) the implants were adhered to the native rabbit cartilage sites (3) pronounced signs of regeneration
in the intermediate zones were observed. The prospects of the cartilage implants use in larynx stenosis surgery are