Bakken Hans E, Kawasaki Hiroto, Oya Hiroyuki, Greenlee Jeremy D W, Howard Matthew A
Department of Neurosurgery, University of Iowa, Iowa City, Iowa, USA.
J Neurosurg. 2003 Sep;99(3):604-8. doi: 10.3171/jns.2003.99.3.0604.
Neurosurgeons use invasive mapping methods during surgery to understand the functional neuroanatomy of patients. Electrical stimulation methods are used routinely for the temporary disruption of focal regions of cerebral cortex so that the surgeon may infer the functional role of the brain site being stimulated. Although it is an efficient and useful method, modes of electrical stimulation mapping have significant limitations. Neuroscientists use focal cooling to effect a more controlled disruption of cortical functions in experimental animals, and in this report, the authors describe their experience using a device to achieve this same objective in patients undergoing neurosurgery. The cooling probe consists of a stainless steel chamber with thermocouples and electroencephalography (EEG) recording contacts. Active cooling is achieved by infusing chilled saline into the chamber when the cooling probe is positioned on the pial surface. Experiments were performed in 18 patients. Temperature gradient measurements indicate that the entire thickness of gray matter under the probe is cooled to temperatures that disrupt local synaptic activity. Statistically significant changes in spontaneous and stimulus-evoked EEG activity were consistently observed during cooling, providing clear evidence of reversible disruption of physiological functions. Preliminary findings during functional mapping of the Broca area demonstrated qualitative differences between the temporary neurological deficits induced by cooling and those caused by electrical stimulation. These findings indicate the safety and utility of the cooling probe as a neurosurgical research tool. Additional rigorously designed studies should be undertaken to correlate the effects of cooling, electrical stimulation, and focal lesioning.
神经外科医生在手术过程中使用侵入性测绘方法来了解患者的功能神经解剖结构。电刺激方法通常用于临时破坏大脑皮质的局部区域，以便外科医生能够推断被刺激脑区的功能作用。尽管这是一种有效且有用的方法，但电刺激测绘模式存在显著局限性。神经科学家在实验动物中使用局部冷却来更可控地破坏皮质功能，在本报告中，作者描述了他们在接受神经外科手术的患者中使用一种装置来实现相同目标的经验。冷却探头由一个带有热电偶和脑电图（EEG）记录触点的不锈钢腔室组成。当冷却探头置于软脑膜表面时，通过向腔室内注入冷盐水来实现主动冷却。对18名患者进行了实验。温度梯度测量表明，探头下方灰质的整个厚度被冷却到破坏局部突触活动的温度。在冷却过程中持续观察到自发和刺激诱发的EEG活动有统计学意义的变化，这为生理功能的可逆破坏提供了明确证据。在布罗卡区功能测绘期间的初步发现表明，冷却诱导的临时神经功能缺损与电刺激引起的缺损在性质上存在差异。这些发现表明冷却探头作为一种神经外科研究工具的安全性和实用性。应该进行更多严格设计的研究，以关联冷却、电刺激和局灶性损伤的效果。
