Scheiner A, Polando G, Marsolais E B
Department of Veterans Affairs Medical Center, Cleveland, OH 44106.
IEEE Trans Biomed Eng. 1994 May;41(5):425-31. doi: 10.1109/10.293216.
An electrode, designed to be implanted without a surgical incision, was developed for skeletal muscle stimulation. Stainless steel, Teflon-insulated wire was wound into a helical lead around a polypropylene core and then rewound into a double helix configuration for stress relief during muscle contractions. The electrode tip was augmented with stainless steel barbs to increase anchoring strength. Electrodes were implanted with the help of specially modified hypodermic needles, sheaths, and passing tubes. 775 electrodes were implanted in a five year period in 22 subjects; accumulated implant time was 1,080 electrode years. 453 electrodes (65%) continue to produce strong, stable, muscle contractions. Electrode longevity varied with the location of implant. Electrodes were removed because of (1) inability to locate and properly place the electrode in a suitable site for stimulation during surgery (28.4%), (2) unwanted changes in muscle response to stimulation (91, 12%; one-third occurring during the first six weeks post implant), (3) increase in electrode impedance (74, 10%; assumed breakage, mostly occurring during the first year after implant), (4) intolerable pain during stimulation (8, 1%), and (5) infection (4, 0.5%). 67 (8%) electrodes were removed by accident or when the subjects left the program. This double helix electrode design has proven practical for achieving chronic stimulation of selected muscles in hemiplegic, paraplegic, stroke and brain-injured subjects with minimally invasive surgery.
一种无需手术切口即可植入的电极被开发用于骨骼肌刺激。不锈钢、聚四氟乙烯绝缘的导线绕在聚丙烯芯上形成螺旋状导线，然后重新绕成双螺旋结构以缓解肌肉收缩时的应力。电极尖端用不锈钢倒刺增强以增加锚固强度。电极借助经过特殊改良的皮下注射针、护套和穿管进行植入。在五年时间里，22名受试者共植入了775个电极；累计植入时间为1080电极年。453个电极（65%）继续产生强烈、稳定的肌肉收缩。电极的使用寿命因植入位置而异。电极被移除的原因包括：（1）在手术过程中无法找到并将电极正确放置在合适的刺激部位（28.4%）；（2）肌肉对刺激的反应出现意外变化（91个，12%；其中三分之一发生在植入后的前六周）；（3）电极阻抗增加（74个，10%；推测为断裂，大多发生在植入后的第一年）；（4）刺激过程中出现无法忍受的疼痛（8个，1%）；（5）感染（4个，0.5%）。67个（8%）电极因意外或受试者退出项目而被移除。这种双螺旋电极设计已被证明对于通过微创手术实现对偏瘫、截瘫、中风和脑损伤受试者选定肌肉的长期刺激是切实可行的。
