Hayashi N, Sugawara T, Goto T, Takeuchi T, Tsubokawa T
No Shinkei Geka. 1976 Aug;4(8):739-45.
The interstitial pressure of the brain was measured with wick catheter by Lassen in 1972. But original wick catheter inserted into the brain tissue does not always measure the real interstitial pressure as indicated by experimental results of Brodersen, because, the interstitial pressure is always affected by solid pressure such as cells in the brain tissue, in the condition of which surrounded by positive CSF pressure in the semiclosed skull box. It is not yet clarified what kinds of the pressure are measured by wick catheter method in the brain tissue. The size of wick catheter is 300-500 times as large as the width of interspace of the brain tissue and the catheter is easily obstructed by brain tissue. Therefore, a new, modified wick catheter is made for improvement of these problems which is observed by using original wick catheter. The new, modified catheter has 0.4 mm inside diameter and 10 cm length. The tip of catheter is closed and 6 small side holes(0.1 mm0)are made. Inside the catheter, several pieces of 0.04 mm diameter nylon threads are inserted as shown in figure 1, and the catheter is filled up with the cerebrospinal fluid. In this paper, the structure of the new, modified catheter is demonstrated, and the brain tissue pressure is measured, comparing with the results of the original wick catheter to test the function of the new, modified catheter. The results of measurement of the brain tissue fluid pressure with the new, modified catheter are as follows; 1) The brain tissue fluid pressure is relatively constant and shows a positive pressure of 5.2 mmHg. 2) As there are few blocking effects in the catheter, the new, modified catheter is useful for the measurement of the brain tissue fluid pressure for a long time. 3) The brain tissue fluid pressure is not altered by the number's of nylon threads in the catheter at static condition, but movement of brain tissue fluid pressure with respiration is a little dumped by the increased conductancy with the numbers of nylon threads in the catheter. 4) The tissue fluid pressure affected by the viscosity and osmolarity of the fluid in the catheter, CSF should be used for correct measurement. According to these results, it might be concluded that the new, modified wick catheter is better than the original wick catheter regarding prevention of obstruction of the catheter by brain tissue fragments, artifacts which causet by movement of wick fibers, measurement of brain tissue fluid pressure for a long time and clarify the resistance of catheter to pressure conductancy.
1972年，拉森用灯芯导管测量了脑间质压力。但正如布罗德森的实验结果所示，插入脑组织的原始灯芯导管并不总能测量到真正的间质压力，因为在半封闭的颅骨箱中，脑间质压力总是受到脑组织中细胞等固体压力的影响，且周围存在正性脑脊液压力。目前尚不清楚灯芯导管法在脑组织中测量的是何种压力。灯芯导管的尺寸是脑组织间隙宽度的300 - 500倍，导管很容易被脑组织阻塞。因此，为改善使用原始灯芯导管时观察到的这些问题，制作了一种新的改良灯芯导管。新的改良导管内径为0.4毫米，长度为10厘米。导管尖端封闭，有6个0.1毫米的小侧孔。如图1所示，在导管内插入几根直径为0.04毫米的尼龙线，导管内充满脑脊液。本文展示了新的改良导管的结构，并测量了脑组织压力，与原始灯芯导管的结果进行比较，以测试新改良导管的功能。用新改良导管测量脑组织液压力的结果如下：1）脑组织液压力相对恒定，显示正压5.2 mmHg。2）由于导管堵塞作用小，新改良导管可用于长时间测量脑组织液压力。3）在静态条件下，导管中尼龙线的数量不会改变脑组织液压力，但随着导管中尼龙线数量增加，传导性增强，脑组织液压力随呼吸的波动会稍有减弱。4）导管内液体的粘度和渗透压会影响组织液压力，应使用脑脊液进行准确测量。根据这些结果，可以得出结论，在防止脑组织碎片阻塞导管、灯芯纤维移动引起的伪像、长时间测量脑组织液压力以及明确导管对压力传导性的阻力方面，新改良灯芯导管优于原始灯芯导管。
