Recovery profile of single motoneurons after electrical stimuli in man

The H-reflex of 120 soleus motoneurons was recorded using fibre EMG. The recovery profile of these motoneurons was studied during monitoring surface H-reflex records in 28 adult subjects. The spectrum of motoneurons tested was homogeneous with two extremes of neurons having different characteristics. A motoneuron population (forming about 69% of our sample) had a high threshold level for electrical stimuli, short recovery time, and short recovery fringe time (called type A). A second population of motoneurons (forming about 20-30% of our sample) had a low threshold level for electrical stimuli, long recovery fringe time (called type B). During an isometric muscle contraction every motoneuron showed an early shift in recovery time (i.e. each had a shorter recovery time) with shortened recovery fringe time. These changes were larger for motoneurons type B than motoneurons type A. With paired identical electrical stimuli of varying interstimulus intervals a motoneuron may fire in response to the conditioning and test stimuli giving an H2, but not in response to both stimuli. This occurred for interstimulus intervals of 4-11 ms. A strong inhibition period was recorded with interstimulus intervals of 12-80 ms in which all motoneurons did not show any recovery. Most motoneurons recovered in orderly fashion between 80 and 300 ms of interstimulus interval, and this recovery coincided with the fast recovery recorded in surface H-reflex. All motoneurons were recovered by 3000 ms of interstimulus intervals. These findings emphasize the importance of eliciting the H-reflex every 3-5 s in H-reflex methodology in order to be assured that all excited motoneurons have been recovered.     

Mechanisms mediating the brain stem control of somatosensory transmission in the dorsal horn of the cat's spinal cord: an intracellular analysis

Summary The effect of brainstem stimulation was studied on neurones recorded intracellularly in the superficial and deeper laminae of the lumbosacral dorsal horn of the spinal cord in anaesthetised cats. Stimulation in the nucleus locus coeruleus (LC) produced a hyperpolarisation in 4/13 multireceptive neurones and produced a biphasic action consisting of a hyperpolarisation which was followed by a depolarisation in 3/13 neurones. These actions were produced irrespective of whether the multireceptive neurone was located in the superficial or deeper laminae of the dorsal horn. Stimulation failed to produce postsynaptic potentials in the remaining 6/13 multireceptive neurones. The amplitude of hyperpolarisation was increased by the passage of depolarising pulses through the recording microelectrode and decreased by hyperpolarising pulses. Stimulation in other brainstem areas such as, the lateral (FTL), paralemniscal (FTP) and central (FTC) divisions of the tegmental field and the nuclei raphe magnus (NRM) and reticularis magnocellularis (RMc) also hyperpolarised neurones in the dorsal horn. The polarity of hyperpolarisation evoked from some brainstem areas (FTP, FTC, RMc) could be reversed to depolarisation by the passive diffusion of ions from the recording microelectrode containing 3M-KCl. Brainstem (LC, NRM, FTP, FTL) stimulation generated long lasting (700 ms) hyperpolarisation on 4/4 selectively nocireceptive neurones of lamina I. There was, however, no effect on the activity of 5/5 neurones recorded in laminae I/II which in addition to receiving excitatory cutaneous inputs were inhibited by heat stimuli. Stimulation in LC also produced dorsal root potentials (DRPs) and reduced the amplitude of simultaneously recorded excitatory postsynaptic potentials (EPSPs) generated by the activation of primary afferent fibres in 3 multireceptive neurones. It is concluded that inhibition of nociceptive transmission in the spinal cord from LC and other brainstem areas may involve both pre- and postsynaptic mechanisms.     

单侧入路椎体后凸成形术治疗老年骨质疏松性胸腰椎压缩性骨折临床研究

目的：探讨单侧入路椎体后凸成形术治疗老年骨质疏松性胸腰椎压缩性骨折的临床疗效和安全性。方法：将15例老年骨质疏松性胸腰椎压缩性骨折患者，行单侧入路穿刺椎体后凸成形术。记录手术时间和透视次数，观察术后患者背痛缓解程度及日常活动恢复情况，比较术前、术后伤椎高度和脊柱后凸畸形Cobb’S角。结果：15例患者均顺利完成手术，手术时间25～43min，平均28．6min；透视次数15～23次，平均19．8次；术后伤椎前部、中部高度，脊柱后凸畸形Cobb’S角与术前比较，差异有统计学意义（P〈0．05）；术后24h患者背痛均明显缓解，与术前比较差异有统计学意义（P〈0．05）。患者均能在术后次日下床行走，未发现神经损伤等手术并发症。结论：单侧入路穿刺球囊扩张椎体后凸成形术能有效地治疗老年骨质疏松性胸腰椎压缩性骨折，且操作简便、安全，能明显地减少患者和术者的放射暴露。     

罗哌卡因腰硬联合麻醉在老年患者下肢手术中的应用

目的：探讨罗哌卡因腰硬联合麻醉应用于老年患者下肢手术的有效性和安全性。方法：选择在腰硬联合麻醉下择期行下肢手术的老年患者60例，随机分为2组，每组30例。Ⅰ组采用0．75％盐酸罗哌卡因1．2mL，Ⅱ组采用0．75％盐酸布比卡因1．2mL，均以脑脊液稀释后蛛网膜下腔给药，术中麻醉效果不佳时硬膜外腔追加1．5％利多卡因5—10mL。观察比较两组患者的感觉、运动阻滞情况和不良反应发生情况。结果：两组患者在感觉阻滞起效时间、最高感觉阻滞平面、T12阻滞维持时间方面，差异无统计学意义（P〉0．05）；与Ⅱ组相比，Ⅰ组患者运动阻滞起效时间长，最大Bromage评分小，Bromage 1分的维持时间短，差异有统计学意义（P〈0．05）；两组患者不良反应的发生率比较，差异无统计学意义（P〉0．05）。结论：罗哌卡因腰硬联合麻醉可安全有效地用于老年患者下肢手术。     

腰椎后路非融合固定系统的临床应用

复习腰椎后路非融合固定系统的设计原理、临床应用及治疗效果等相关文献,与传统的脊柱融合术相比,应用非融合系统可获得很好的疗效,并可以减少邻近节段退变的发生率。     

电针对SNI大鼠痛敏及脊髓相应节段谷氨酸和P物质的影响

目的:探讨电针对神经病理性痛大鼠痛觉过敏以及脊髓谷氨酸和P物质含量的影响。方法:40只SD大鼠,随机分为空白组、假手术组、手术组和电针组(n=10)。采用坐骨神经分支选择性损伤模型,电针"委中"和"环跳"穴,观察其对大鼠机械痛阈和热痛阈的影响,以OPA柱前衍生+HPLC荧光检测和放射免疫分析法测定脊髓相应节段谷氨酸和P物质含量的变化。结果:SNI手术可明显降低大鼠机械痛阈,并且其脊髓相应节段谷氨酸含量明显升高,P物质含量则明显降低;而电针干预后可显著降低大鼠脊髓相应节段谷氨酸的含量,升高P物质含量,并减轻SNI大鼠的机械痛敏状态,进而改善其痛行为。结论:电针干预神经病理性痛的脊髓机制之一可能与其有效的减少大鼠脊髓相应节段谷氨酸和P物质的释放有关。     

Spinal Drop Metastasis from a Posterior Fossa Choroid Plexus Papilloma

Choroid plexus papillomas (CPPs) are typically considered as benign tumors, with a favorable long-term prognosis. Drop metastasis of CPP into the spinal subarachnoid space is rare. We report a 42-year-old woman who presented with headache and back pain 6 years after removal of a posterior fossa CPP. Magnetic resonance imaging revealed mass lesions in the lumbosacral subarachnoid space and recurrent intracranial tumor. The lesions were resected and histologically diagnosed was CPP. We consider that CPP can spread via cerebrospinal fluid pathways and cause spinal drop metastasis. Therefore, it is necessary to evaluate the whole spinal axis and to perform periodic follow-up examinations in patients with CPP.     

Surgery for ventricular tachycardia in patients undergoing surgical ventricular restoration: The Karolinska approach

This article presents a review on the efficacy of surgical ventricular restoration and direct surgery for ventricular tachycardia in patients with left ventricular aneurysm or dilated ischemic cardiomyopathy. The procedure includes a non-electrophysiologically guided subtotal endocardiectomy and cryoablation in addition to endoventricular patch plasty of the left ventricle. Coronary artery bypass surgery and mitral valve repair are performed concomitantly as needed. In our experience, this procedure yielded a 90% success rate in terms of freedom from spontaneous ventricular tachycardia, with an early mortality rate of 3.8%. A practical guide to the pre- and postoperative management of these patients is provided. Electronic supplementary material The online version of this article (doi: ) contains supplementary material, which is available to authorized users.     

丹参注射液椎管内局部灌注对急性脊髓损伤的保护作用

目的 探讨丹参对急性脊髓损伤的防治作用。方法 以改良Allen's法造成兔不完全性脊髓损伤的模型,硬膜下插管。随机分成丹参治疗组和对照组。术后按每天0.3ml/kg体重的总量分4次从硬膜下导管推入丹参注射液,对照组推入生理盐水。损伤后8、72h对脊髓损伤区进行过氧化物歧化酶(SOD)、丙二醛(MDA)、组织形态学观察、神经元凋亡、bcl-2等进行评价。结果 丹参组SOD含量高于对照组(P<0.01),MDA含量低于对照组(P<0.01)。细胞凋亡数目TUNEL法丹参组低于对照组(P<0.01),流式细胞术检测凋亡丹参组低于对照组(P<0.05)。bcl-2的表达丹参组高于对照组(P<0.05)。神经元及神经纤维变性、坏死轻于对照组。结论 丹参能改善损伤脊髓微循环,抑制和减轻脊髓损伤后的两种死亡方式坏死和凋亡。