What is femtolaser surgery?

Answer 1

An area of growing interest is the use of ultra-short pulsed (femtoseconds)

lasers for surgery and tissue ablation (Juhasz et al., 2002). The advantages

offered by these ultra-short pulses are that cuts or ablations can be made more

precisely, with very little collateral damage. The mechanism of laser-tissue

interactions that occur using ultra-short laser pulses is also different from the

photothermal and photoablation mechanisms discussed above because they

pertain to tissue contouring and welding. The high peak power of the ultrashort

pulses lead to photodisruption, discussed in Chapter 6. The mechanism

of photodisruption involves laser-induced optical breakdown (LIOB), in

which a strongly focused short-duration pulse generates a high-intensity electric

field and leads to efficient multiphoton ionization and subsequent

avalanche ionization to produce a hot microplasma. This hot microplasma

expands with supersonic velocity, displacing (ablating or cutting) the surrounding

tissue.

Since the displacement is adiabatic (i.e., it occurs on a time

scale short compared to the local thermal diffusion time), the effect of ablation or cutting is spatially confined and any spread due to thermal damage

is also confined. The wide availability of mode-locked Ti:sapphire lasers

producing ~100-fesec pulses at ~800nm has provided much of the impetus

for using them for femtolaser surgery or tissue ablation.