Walter J S, Griffith P, Scarpine V, Bidnar M, Dauzvardis M, Turner M, McLane J, Sweeney J, Robinson C J
Rehabilitation Research and Development Center, Edward Hines, Jr. Department of Veterans Affairs Hospital, Hines, IL 60141, USA.
J Spinal Cord Med. 1996 Oct;19(4):234-41. doi: 10.1080/10790268.1996.11719439.
The raccoon was evaluated as an animal model for upper limb neural prosthetics. This animal was selected primarily because the functional use of its forelimb mimics in many ways the usage in humans and because of its optimal size and commercial availability. Eight cadaver and fresh specimen forearms were dissected. Important characteristics of the raccoon forearm were: 1) large muscles in the volar forearm, 2) large digits in the paw that appear more similar to humans than to other species such as cat or dog, 3) persistence of two median nerve cords into the forearm, 4) no separation of individual tendons of flexor digitorum superficialis and flexor digitorum profundus in the carpal tunnel, 5) a small thumb digit with little function and 6) a primary origin of flexor policis longus on the proximal ulna with a secondary origin on the radius. Four animals were anesthetized and responses of the forearm and paw to stimulation of the volar forearm muscles with percutaneous electrodes were evaluated. A pair of stimulating electrodes was placed in each of four muscles or muscle groups. Recording electrodes were placed in two muscles which showed the greatest separation of muscle movements to stimulation. Stimulation currents just above threshold produced discrete motion as well as recordable EMG M-waves. Incremental increases in stimulation current produced an increase in M-wave amplitude up to a maximal stimulating current. Torque recordings for pronation, wrist flexion and finger flexion showed graded and selective responses. These results including anatomical descriptions indicate both the limitations of this animal model and its potential use in the development of upper limb neural prosthetics. We conclude that the raccoon model may be superior to other nonprimate animal models such as the cat because of its extensive forearm and paw movements.
浣熊被评估为上肢神经假体的动物模型。选择这种动物主要是因为其前肢的功能使用在许多方面模仿人类，并且因其最佳的体型和商业可得性。解剖了八个尸体和新鲜标本的前臂。浣熊前臂的重要特征有：1）掌侧前臂肌肉较大；2）爪子中的大指与人类的更相似，而与猫或狗等其他物种不同；3）两条正中神经索持续进入前臂；4）腕管内指浅屈肌和指深屈肌的各条肌腱未分离；5）拇指较小且功能有限；6）拇长屈肌主要起于尺骨近端，次要起于桡骨。对四只动物进行麻醉，并使用经皮电极刺激掌侧前臂肌肉，评估前臂和爪子的反应。在四块肌肉或肌肉群中各放置一对刺激电极。记录电极置于两块肌肉中，这两块肌肉在受到刺激时肌肉运动的分离最大。略高于阈值的刺激电流产生离散运动以及可记录的肌电图M波。刺激电流的递增会使M波振幅增加，直至达到最大刺激电流。旋前、腕屈曲和手指屈曲的扭矩记录显示出分级和选择性反应。这些结果包括解剖学描述，既表明了这种动物模型的局限性，也表明了其在上肢神经假体开发中的潜在用途。我们得出结论，由于浣熊模型的前臂和爪子运动范围广，它可能优于其他非灵长类动物模型，如猫。
