Spinal root stimulation for restoration of function in lower-limb amputees

项目摘要 设计和致动方面的最新进展已经导致假肢的重要改进。然而，这些设备 缺乏提供直接感觉反馈的手段，需要用户从压力推断关于肢体状态的信息。 残肢感觉的缺乏限制了他们控制假肢的能力，导致步态缓慢，增加了患 下降还有证据表明，缺乏感觉反馈会导致幻肢痛（PLP），而电刺激会导致幻肢痛。 刺激背根神经节（DRG）可降低PLP。本研究的主要目的是商业化使用 FDA批准的脊髓刺激器（SCS）电极导线，用于测试DRG和背侧神经节电刺激的效果 小根（DR）作为恢复自然感觉（例如压力、运动）、减少PLP和改善步态的手段 在经胫骨截肢者中的功能。我们将使用刺激来（1）产生压力和关节运动的感觉，（2） 减少PLP，（3）诱发肌肉活动模式，模仿站立期间正常发生的自动反应， 行走，以及（4）当用传感器假肢站立和行走时改善姿势稳定性。 目的1：使用DRG/DR的刺激来产生压力和关节运动的自然感觉，局部 截肢，并实现临床相关的减少幻肢疼痛 为了提供直观的反馈，诱发的感觉应该被感知为起源于截肢，并且应该感觉到 自然主义的PLP的伴随降低也可能对生活质量产生重要影响。我们将进行详细的 心理物理测试，其中刺激参数变化，同时要求研究参与者报告信息 关于诱发的感觉（例如位置、模态、自然度）和对PLP的影响。 目的2：表征DRG/DR刺激诱发的完整和截肢肢体的运动反应， 它们与刺激参数的关系 在应对滑倒和绊倒等意外干扰时，双侧协调反射发挥着重要作用。 此外，步态阶段之间的转换主要是由对来自身体的感觉输入的反射性反应介导的。 腿对于恢复截肢者站立和行走的全部能力的假肢， 并精确控制这些反射活动的模式将是至关重要的。我们将记录肌电图（EMG）信号 从四肢站立和行走，同时改变刺激模式，并量化 刺激参数和诱发的反射反应。理解这些关系将有助于 用于功能性假体的刺激模式。 目的3：通过DRG/DR刺激提供感觉反馈，减少姿势摇摆并增加步态稳定性 为了量化感觉恢复对假肢使用的功能影响，我们将检测每个参与者的 具有压敏鞋垫和关节角度传感器的假肢，并使用来自这些装置的信号来调节 刺激.我们将进行一系列姿势和平衡测量，我们将跟踪功能性假肢的变化， 在7天的设备带回家试用后使用。

PROJECT SUMMARY Recent advances in design and actuation have led to important improvements in prosthetic limbs. However, these devices lack a means for providing direct sensory feedback, requiring users to infer information about limb state from pressure on the residual limb. Lack of sensation limits their ability to control the prosthesis and leads to slow gait and increased risk of falling. There is also evidence that lack of sensory feedback contributes to phantom limb pain (PLP), and that electrical stimulation at the dorsal root ganglia (DRG) can reduce PLP. The primary objective of this study is to use commercially available, FDA-cleared spinal cord stimulator (SCS) leads to test the effects of electrical stimulation of the DRG and dorsal rootlets (DR) as a means of restoring naturalistic sensation (e.g. pressure, movement), reducing PLP, and improving gait function in transtibial amputees. We will use stimulation to (1) produce sensations of pressure and joint movement, (2) reduce PLP, (3) evoke patterns of muscle activity that mimic automatic responses that occur normally during standing and walking, and (4) improve postural stability when standing and walking with a sensorized prosthesis. Aim 1: Use stimulation of the DRG/DR to generate naturalistic sensations of pressure and joint movement, localized to the amputated limb, and achieve a clinically relevant reduction in phantom limb pain To provide intuitive feedback, evoked sensations should be perceived as originating in the amputated limb and should feel naturalistic. A concomitant reduction in PLP may also have important effects on quality of life. We will perform detailed psychophysical testing in which stimulation parameters are varied while study participants are asked to report information about the evoked sensation (e.g. location, modality, naturalness) and the effects on PLP. Aim 2: Characterize the motor responses in the intact and amputated limbs evoked by DRG/DR stimulation and their relationship to stimulation parameters Bilaterally coordinated reflexes play an important role when responding to unexpected perturbations like slips and trips. Additionally, the transitions between phases of gait are largely mediated by reflexive responses to sensory input from the legs. For a prosthesis to restore the full capabilities of the amputated limb during standing and walking, the ability to evoke and precisely control these patterns of reflexive activity will be critical. We will record electromyogram (EMG) signals from the limbs during standing and walking while varying stimulus patterns and quantify the relationships between stimulation parameters and evoked reflexive responses. Understanding these relationships will aide in the programming of stimulation patterns for functional prosthesis use. Aim 3: Decrease postural sway and increase gait stability by providing sensory feedback via DRG/DR stimulation To quantify the functional impact of sensory restoration on prosthetic limb usage, we will instrument each participant’s prosthetic limb with a pressure sensitive insole and joint angle sensors, and use signals from these devices to modulate stimulation. We will perform a battery of posture and balance measures, and we will track changes in functional prosthesis usage after a 7-day take-home trial of the device.