Holmium: YAG laser-induced liquid jet knife: possible novel method for dissection.
OBJECTIVE
Making surgical incisions in vessel-rich organs without causing bleeding is difficult. Thus, it is necessary to develop new devices for this purpose, especially for surgery involving small vessels as in neurosurgery, where damage against even small cerebral vessels result in severe neurological deficits.


METHODS
A laser-induced liquid jet was generated by irradiating pulsed Holmium Yttrium-Aluminum-Garnet (Ho: YAG) laser (beams of 350 microseconds pulse width) within a copper tube (internal diameter, 1 mm) with pure water (150 ml /hour). Ho: YAG laser beams were irradiated through an optical fiber (core diameter, 0.4 mm). The influence of the input of laser energy, structure of the nozzle, and the stand-off distance between the optical fiber tip and nozzle exit on the jet velocity was measured by a high-speed video camera to evaluate controllability of jet. The effect on artificial organs made of 10 and 30%(w/v) gelatin, each of which represent features of soft tissue and blood vessels.


RESULTS
Jet velocity increased in proportion to gain in laser energy input, and maximum penetration depth into 10%(w/v) gelatin was 35 mm by single exposure at 350 mJ/pulse without impairing a vessel model. Shapes of nozzle also modified jet velocity with optimal nozzle/tube area ratio of 0.25.


CONCLUSIONS
The laser-induced liquid jet has excellent potential as a new tool for removing soft tissue without damaging vital structures.
Nakagawa
Atsuhiro
A
Department of Neurosurgery, Tohoku University Graduate School of Medicine, Sendai 980-8574, Japan. nakg@nsg.med.tohoku.ac.jp
Hirano
Takayuki
T
Komatsu
Makoto
M
Sato
Mariko
M
Uenohara
Hiroshi
H
Ohyama
Hideki
H
Kusaka
Yasuko
Y
Shirane
Reizo
R
Takayama
Kazuyoshi
K
Yoshimoto
Takashi
T
D004210:Dissection / Q000295:instrumentation* / Q000379:methods*; D004867:Equipment Design; D006801:Humans; D053685:Laser Therapy / Q000295:instrumentation* / Q000379:methods*; D008954:Models, Biological; D011829:Radiation Dosage; D015203:Reproducibility of Results; D012212:Rheology; D013997:Time Factors