Comparative Analysis of Biotissue Laser Resection Using Strongly Absorbing Optical Fiber Tips

Abstract

We present a laser resection technique to be used when biotissue is heated by laser radiation to the temperature of material softening and then moved apart by the lateral edge of the optical fiber with a strongly absorbing tip. The absorbing tip allows the decrease in the power of effective cutting of the laser scalpel at the wavelength of 0.97 µm. And it changes the resection speed as well as the characteristics of the damage of the tissues adjacent to the incision in experiments on model media and experimental animals.

The influence on biotissue laser resection of a strongly absorbing layer at the optical fiber tip

“…We studied a carbon coating and an SAC based on silicone varnish. 13 Two modes of contact tissue-cutting were investigated: one with a clear tip to the operating¯ber and the other with the SAC tip. The contact exposure of animal integument to laser radiation with the¯ber laser tips was performed by an experienced laser surgeon.…”

“…Radiation with a power of 7 W was taken as being optimal as a result of data from Ref. 13 for the uncoated¯ber. The same power was used for comparative analysis with the SAC¯ber.…”

“…12 At the same time, the carbon layer which forms is also a strong radiation absorber across a wide range of wavelengths and this results in an interesting unstable mode of laser cutting. Preliminary experiments to study this e®ect on ex-vivo samples have demonstrated that the absorbing layer permits an increase in the e®ective resection speed of the laser scalpel by 0.97 m. 13 However, no comparative study has yet been undertaken of the scar characteristics during tissue regeneration after conventional laser resection and after resection using the absorbing coating, so the mechanism of the e®ect is not clear at this stage.…”

On the possible ultrasonic inspection of micro-bubbles generated by the optical fiber tip

“…So strongly absorbing coating is applied on the tip of the optical¯ber to increase its temperature. 2,6,8 Typically, a carbon-containing compound supplied with the surgical laser is used.…”

“…On the one hand, it considerably increases the cutting speed and reduces blood loss, which has a bene¯cial e®ect on post-surgery wound healing. [4][5][6] On the other hand, it gives rise to acoustic°ows and leads to the generation of bubbles of di®erent sizes ranging from fractions of a millimeter, the noise of which is heard as a \boiling" noise, to the size of the micron level. 3,7,8 The cavitation bubbles collapse, creating powerful acoustic streaming and shock waves causing, in particular, the death of bacteria, and thereby sterilizing the wound.…”