Protracted myelin clearance hinders central primary afferent regeneration following dorsal rhizotomy and delayed neurotrophin-3 treatment

Regeneration within or into the CNS is thwarted by glial inhibition at the site of a spinal cord injury and at the dorsal root entry zone (DREZ), respectively. At the DREZ, injured axons and their distal targets are separated by degenerating myelin and an astrocytic glia limitans. The different glial barriers to regeneration following dorsal rhizotomy are temporally and spatially distinct. The more peripheral astrocytic barrier develops first, and is surmountable by neurotrophin-3 (NT-3) treatment; the more central myelin-derived barrier, which prevents dorsal horn re-innervation by NT-3-treated axons, becomes significant only after the onset of myelin degeneration. Here we test the hypothesis that in the presence of NT-3, axonal regeneration is hindered by myelin degeneration products. To do so, we used the Long Evans Shaker (LES) rat, in which oligodendrocytes do not make CNS myelin, but do produce myelin-derived inhibitory proteins. We show that delaying NT-3 treatment for 1 week in normal (LE) rats, while allowing axonal penetration of the glia limitans and growth within degenerating myelin, results in misdirected regeneration with axons curling around presumptive degenerating myelin ovoids within the CNS compartment of the dorsal root. In contrast, delaying NT-3 treatment in LES rats resulted in straighter, centrally-directed regenerating axons. These results indicate that regeneration may be best optimized through a combination of neurotrophin treatment plus complete clearance of myelin debris.     

原发性舌咽神经痛的脑内窥镜微创治疗

目的探讨在脑内窥镜下乙状窦后入路舌咽神经微创手术治疗原发性舌咽神经痛的临床效果。方法2000年1月～2008年5月,对16例原发性舌咽神经痛,在脑内窥镜下经乙状窦后入路行舌咽神经微血管减压/切断术。患侧耳后纵行发际内缘切口,桥小脑角池释放脑脊液,形成操作通道,在脑内窥镜下广泛分离松解蛛网膜粘连,探查舌咽神经结构以及局部动脉走形。其中行舌咽神经切断术9例,单纯血管减压加舌咽迷走神经梳理7例。结果16例咽部疼痛术后均消失。16例随访3个月～8年,其中1～3年4例,3～8年2例。声音嘶哑2例,无吞咽困难,无复发。结论该手术具有创伤轻微、视野清晰、操作精确、疗效确切、术后反应轻、恢复快等特点。     

选择性脊神经后根部分切断术治疗痉挛性脑瘫

目的 探讨选择性脊神经后根部分切断术治疗痉挛性脑瘫的临床效果.方法 对39例痉挛性脑瘫患儿行SPR术.结果 39例患者术后肢体痉挛程度降低Ⅱ级15例,降低Ⅰ级24例;肌张力降低Ⅱ级20例,降低Ⅰ级19例.随访:痉挛缓解率为94%,步态功能改善率93%.结论 SPR术是治疗痉挛性脑瘫的满意方法.     

运动疗法在脑瘫儿童选择性脊神经后根切断术后康复中的应用

目的：分析运动疗法在脑瘫儿童选择性脊神经后根切断术后康复中的临床疗效,为脑瘫儿童的康复提供可靠方法。方法：2003年9月至2007年4月脑瘫患儿226例,男125例,女101例;年龄3～10岁,平均6．8岁;随机分为对照组113例和治疗组113例。治疗组：男66例,女47例;年龄3-8岁,平均（6．5±1．2）岁;采用选择性脊神经后根切断术同时辅以运动疗法。,对照组：男59例,女54例;年龄3～10岁,平均（6．9±1．5）岁;采用选择性脊神经后根切断术。两组治疗前后采用小儿脑瘫粗大运动功能测试量表（CMFM）、肌张力评分、被动关节活动度进行评估。结果：226例均获随访,时间6～18个月,平均8个月。治疗后组间进行比较：治疗组GMFM得分平均（134．29±46．43）分,高于对照组（P〈0．05）;肌张力评分平均（1．27±0．42）分,优于对照组（P〈0．05）;关节活动度中踝背屈角度平均（14．2±3．1）°,大于对照组（P〈0．05）。结论：运动疗法在脑瘫儿童SPR术后康复中具有明显效果,有助于减轻痉挛状态、降低肌张力、改善脑瘫儿童的运动功能。     

Concentration of amino acid neurotransmitters in the somatosensory cortex of the rat after surgical or functional deafferentation

Hindlimb unloading is considered as a model of functional deafferentation, since in this situation the tactile information from the paw and the proprioceptive input from the limb are dramatically reduced. Unloading induces a shrinkage of the cortical representation of the affected body part associated to a reorganization of topographic maps and to an expansion of receptive fields. Previous studies have suggested that cortical plasticity was the result of a change in the balance of excitation and inhibition in the cortex. The aim of the present study was thus to determine whether deafferentation of the hindlimb representation in the somatosensory cortex, by 14 days of unloading or by surgical means (selective dorsal rhizotomy during 17 days), can change the concentration in various amino acid neurotransmitters in the deprived cortex. The present findings indicate that both types of deafferentation result in a decrease in inhibitory amino acids (GABA, taurine) without significant changes in the main excitatory amino acid (glutamate). In conclusion, the present results support the idea that cortical changes are more likely due to a release from inhibition than to an increased excitation.     

腰骶段选择性脊神经后根切断术治疗脑瘫性下肢痉挛状态的远期疗效分析

目的 腰骶段选择性脊神经后根部分切断术(selective posterior rhizotomy,SPR)是公认的治疗脑瘫性下肢痉挛状态的手术方法,但对其远期疗效仍然存在争议.此研究的目的是使用标准化评估手段系统地探讨SPR治疗脑瘫性下肢痉挛状态的远期疗效.方法 回顾性分析141例平均随访9.7年且临床资料完整的脑瘫性下肢痉挛状态患者.分别在术前、术后1年、5年、终末时进行随访,评估手段包括定量的下肢肌张力标准化评估(改良Ashworth 6级量表)、粗大运动功能分级情况(GMFCS分级)、日常生活能力评分(ADL量表),并结合患者后续接受的治疗措施进行统计分析,以评估SPR的远期疗效.结果 患者术后下肢肌张力均有明显下降,末次随访时,下肢三大肌群肌张力改良Ashworth分级与术前比较差异均有统计学意义(P＜0.01);随访期间肌张力总体改善率90.7％.GMFCS分级与术前比较差异有统计学意义(P＜0.01),随访期间粗大运动功能较术前总体改善率为80.1％.日常生活能力评分与术前比较差异有统计学意义(P＜0.01),随访期间总体生活质量改善率为88.9％.术前GMFCS分级Ⅰ～Ⅲ级的患者术后ADL得分随时间延长而持续上升.截至到末次随访时患者所接受后续的周围神经选择性部分切断术、跟腱延长术、骨关节矫形术或痉挛肌肉肉毒素注射治疗的总体比例为27.7％,统计学分析示:是否接受后续治疗措施在末次随访时ADL改善程度上差异有统计学意义(P＜0.01).结论 腰骶段SPR治疗脑瘫性下肢痉挛状态的疗效可长期持续存在,其远期疗效包括肌张力、粗大运动功能和日常生活能力的改善,其中术前GMFCS分级Ⅰ～Ⅲ级的患者远期疗效最为显著.SPR术后联合必要的后续外科治疗措施有助于疗效维持及运动功能改善,并最终表现为日常生活能力的提高.     

SPR治疗脊髓损伤后下肢痉挛的临床观察

目的:探讨采用选择性脊神经后根切断术(SPR)治疗脊髓损伤后下肢痉挛的效果。方法:16例患者术前3d进行步态分析,术中对支配痉挛下肢的L2～S1的脊神经后根进行分束,电刺激仪测阈值,将阈值较低神经束切断。神经根切断比例结合肌张力、肌力、体重及肌群功能进行量化,均小于30%。结果:术后步态有明显改善(P<0.01)。16例平均随访3年,痉挛解除率90%,功能改善率80%。结论:选择性脊神经后根切断术能较有效地治疗脊髓损伤后下肢痉挛。