Hirano T, Nakagawa A, Uenohara H, Ohyama H, Jokura H, Takayama K, Shirane R
Department of Neurosurgery, Tohoku University Graduate School of Medicine, Sendai, Japan.
Acta Neurochir (Wien). 2003 May;145(5):401-6; discussion 406. doi: 10.1007/s00701-003-0010-9.
Neurosurgery has long required a method for dissecting brain tissue without damaging principal vessels and adjacent tissue, so as to prevent neurological complications after operation. In this study we constructed a prototype of such a device and used it in an attempt to resect beagle brain cortex.
The prototype device consisted of an optical fibre, a Y adaptor, and a nozzle whose internal exit diameter was 100 microm. Cold physiological saline (4 degrees C) was supplied to it at a rate of 40 ml/h. Pulsed liquid jets were ejected from the nozzle by a pulsed Holmium:YAG) (Ho:YAG) laser at an irradiation energy of 300 mJ/pulse. The profile of the liquid jet was observed with a high-speed camera while changing the distance between the optical fibre end and nozzle exit (equivalent to the standoff distance). With this device (3 Hz operation), brain dissection of anaesthetized beagles was attempted while measuring the local temperature of the target. A histological study of the incised parts was also performed.
When the standoff distance was 24 mm, the liquid jet was emitted straight from the nozzle at a maximum initial velocity of 50 m/s. The brain parenchyma was cut with this device while preserving vessels larger than 200 microm in diameter and keeping the operative field clear. The local temperature rose to no more than 41 degrees C, below the functional heat damage threshold of brain tissue. Histological findings showed no signs of thermal tissue damage around the dissected margin.
The Ho:YAG laser-induced liquid jet dissector can be applied to neurosurgery after incorporating some minor improvements.
神经外科长期以来一直需要一种在不损伤主要血管和相邻组织的情况下解剖脑组织的方法，以防止术后神经并发症。在本研究中，我们构建了这样一种设备的原型，并将其用于切除比格犬的脑皮质。
该原型设备由一根光纤、一个Y型适配器和一个内部出口直径为100微米的喷嘴组成。以40毫升/小时的速率向其供应冷生理盐水（4℃）。脉冲钬：钇铝石榴石（Ho:YAG）激光以300毫焦/脉冲的照射能量从喷嘴中喷出脉冲液体射流。在改变光纤末端与喷嘴出口之间的距离（相当于 standoff 距离）时，用高速相机观察液体射流的轮廓。使用该设备（3赫兹运行），在测量目标局部温度的同时，尝试对麻醉的比格犬进行脑解剖。还对切开部位进行了组织学研究。
当 standoff 距离为24毫米时，液体射流以最大初始速度50米/秒从喷嘴笔直喷出。使用该设备切割脑实质，同时保留直径大于200微米的血管，并保持手术视野清晰。局部温度升高不超过41℃，低于脑组织的功能性热损伤阈值。组织学结果显示，解剖边缘周围没有热组织损伤的迹象。
钬：钇铝石榴石激光诱导液体射流解剖器在进行一些小的改进后可应用于神经外科手术。
