Center for Musculoskeletal Surgery, Department of Orthopaedics, Charité-Universitätsmedizin Berlin, Berlin, Germany.
PLoS One. 2013 Jul 26;8(7):e69500. doi: 10.1371/journal.pone.0069500. Print 2013.
Variability in task output is a ubiquitous characteristic that results from non-continuous motor neuron firing during muscular force generation. However, variability can also be attributed to errors in control and coordination of the motor neurons themselves in diseases such as cerebral palsy (CP). Selective dorsal rhizotomy (SDR), a neurosurgical approach to sever sensory nerve roots, is thought to decrease redundant or excessive afferent signalling to intramedullary neurons. In addition to its demonstrated ability to reduce muscular spasticity, we hypothesised that SDR is able to decrease variability during gait, the most frequent functional motor activity of daily living.
Twelve CP children (aged 6.1 ± 1.3 yrs), who underwent SDR and performed gait analysis pre- and 12 months postoperatively, were compared to a control group of eleven typically developing (TD) children. Coefficients of variability as well as mean values were analysed for: temporal variables of gait, spatial parameters and velocity.
Gait parameters of cadence (p = 0.006) and foot progression angle at mid-stance (p = 0.041) changed significantly from pre- to post-SDR. The variability of every temporal parameter was significantly reduced after SDR (p = 0.003-0.049), while it remained generally unchanged for the spatial parameters. Only a small change in gait velocity was observed, but variability in cadence was significantly reduced after SDR (p = 0.015). Almost all parameters changed with a tendency towards normal, but differences between TD and CP children remained in all parameters.
The results confirm that SDR improves functional gait performance in children with CP. However, almost exclusively, parameters of temporal variability were significantly improved, leading to the conjecture that temporal variability and spatial variability may be governed independently by the motor cortex. As a result, temporal parameters of task performance may be more vulnerable to disruption, but also more responsive to treatment success of interventions such as SDR.
在产生肌肉力量时，由于运动神经元的非连续放电，导致任务输出的可变性是普遍存在的特征。然而，在脑瘫（CP）等疾病中，运动神经元本身的控制和协调也可能导致可变性。选择性脊神经后根切断术（SDR）是一种切断感觉神经根的神经外科方法，据认为它可以减少传入神经对脊髓内神经元的冗余或过度信号传递。除了其减少肌肉痉挛的能力已得到证实之外，我们假设 SDR 还能够减少步态中的可变性，步态是日常生活中最常见的功能性运动活动。
对 12 名接受 SDR 治疗并在术前和术后 12 个月进行步态分析的 CP 儿童（年龄 6.1±1.3 岁）与 11 名正常发育（TD）儿童的对照组进行比较。分析步态的时间变量、空间参数和速度的可变性系数和平均值。
SDR 后步态的步频（p=0.006）和中足站立时的足进角（p=0.041）发生了显著变化。SDR 后，每个时间参数的可变性均显著降低（p=0.003-0.049），而空间参数的可变性基本保持不变。虽然观察到步态速度有小的变化，但步频的可变性在 SDR 后显著降低（p=0.015）。几乎所有参数都朝着正常方向变化，但 TD 和 CP 儿童之间的差异仍然存在于所有参数中。
结果证实 SDR 改善了 CP 儿童的功能性步态表现。然而，几乎完全是，时间可变性参数得到了显著改善，这使得人们猜测时间可变性和空间可变性可能由运动皮层独立控制。因此，任务表现的时间参数可能更容易受到干扰，但也更容易对 SDR 等干预措施的治疗成功做出反应。
