Measurement of friction on straight catheters in in vitro brain and phantom material
Measurement of friction on straight catheters in in vitro brain and phantom material
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DOI：
10.1109/10.664203
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发表时间：
1998-04-01
影响因子：
4.6
通讯作者：
Broaddus, WC
中科院分区：
文献类型：
--
作者：
Ritter, RC;Quate, EG;Broaddus, WC
作为我们对磁立体定向系统（MSS）（一种向大脑提供治疗的手段）研究的一部分，我们测量了用于模拟导管的细直管上的摩擦力。实验使用直径为 1.9 毫米的弹簧加载不锈钢管，该管穿过 5.5 厘米的明胶模型，或者穿过体外小牛脑。管对弹簧外端突然位移的动态响应可估算出管每单位长度的摩擦力。对两种介质中的二十三次运行分析了所表现出的静态和动态摩擦力。在这些系列中，发现明胶体模中的静摩擦力长度为 (0.0132 +/- 0.0012) N cm(-1) [(1.32 +/- 0.12) g cm(-1)]，大脑中的长度为 (0.0079 +/- 0.0008) N cm(-1) [(0.79 +/- 0.08) g cm(-1)]，动力学摩擦系数b被发现为(8.4+/-2.1)N·s·m(-1)/cm脑内导管长度和(16.3+/-7.6)N·s·m(-1)/cm导管在模型材料中的长度。根据这些数据，MSS 将能够在大脑白质和灰质中以 0.02 至 0.05 cm s(-1) 的位移速率移动 20 厘米长、具有类似摩擦力的直导管。未来的研究将评估弯曲路径产生的力。关于体内和体外大脑、动物和人类大脑之间的机械差异，以及脑沟在实际运动路径中的参与，仍然有待解答的问题。
As part of our studies on the magnetic stereotaxis system (MSS), a means of delivering therapies to the bulk brain, we have measured the frictional forces on a thin, straight tube used to simulate a catheter. Experiments were done with a spring-loaded, stainless steel tube of 1.9-mm diameter which was passed through 5.5 cm of gelatin phantom or, alternatively, through in vitro calf brain. The dynamic response of the tube to sudden displacement of the outer end of the spring yields estimates of the tube's friction per unit length. Twenty-three runs in the two media were analyzed for the static and dynamic frictional forces exhibited. In these series the static frictional forces were found to be (0.0132 +/- 0.0012) N cm(-1) [(1.32 +/- 0.12) g cm(-1)] of length in the gelatin phantom and (0.0079 +/- 0.0008) N cm(-1) [(0.79 +/- 0.08) g cm(-1)] of length in brain, The kinetic friction coefficient, b, was found to be (8.4 +/- 2.1) N s m(-1)/cm length of catheter in brain and (16.3 +/- 7.6) N s m(-1)/cm length of catheter in the phantom material. Based on these figures, the MSS will be capable of moving straight catheters of similar friction that are 20-cm long at rates of displacement of 0.02 to 0.05 cm s(-1) in the white and grey matter of the brain. Future studies will evaluate the forces arising from curved paths. Unanswered questions remain as to the mechanical difference between in vivo and in vitro brain, between animal and human brain, and the involvement of sulci in practical paths of motion.