The pathophysiology of spinal cord injury.

The definitive treatment of severe injuries to the spinal cord is yet to be established, except in the few rare cases in which realignment or decompression results in functionally significant salvage of long tracts coursing through the injured cord segments. The author believes that the best chances for successful therapy lie in a better understanding of the process of spinal cord self-destruction.     

Wallerian degeneration of the corticospinal tracts: postmortem MR-pathologic correlations

Postmortem magnetic resonance (MR) images were correlated with the histological findings in two autopsy-proven cases of Wallerian degeneration of the corticospinal and corticopontine tracts associated with cerebral embolic infarction. T2 hyperintensities seen in Wallerian degeneration showed vacuolation of myelin in the early stage, and marked loss of myelin and axons with macrophages in the subacute and chronic stages. Similar T2 hyperintensities seen in the different stages of Wallerian degeneration reflect different histological findings.     

MR images of wallerian degeneration--relation between the time and MR findings of wallerian degeneration

On magnetic resonance (MR) images, wallerian degeneration of the pyramidal tract can be demonstrated as an abnormal intensity showing prolonged T1 and T2 relaxation times corresponding to the corticospinal tract, and/or as shrinkage of the ipsilateral cerebral peduncle and pons. We evaluated 150 cases with supratentorial cerebrovascular accident (CVA) and found the above findings in 35 patients (hematoma 21, infarction 14). The time interval between the ictus of CVA and manifestation of wallerian degeneration on MR images was evaluated. In all 35 cases the foci of CVA located at or extended into the motor cortex, the corona radiata of the pyramidal tract or the posterior limb of the internal capsule. Abnormal signal intensity appeared as early as 5 weeks after ictus and was observed in all 17 cases after 10 weeks. Ipsilateral shrinkage of the cerebral peduncle and the pons has appeared 13 months after ictus. MR appears to be the most useful modality for early detection of waller degeneration.     

MRI findings in posttraumatic spinal cord Wallerian degeneration

We present MRI findings in a patient who presented with a remote cervical cord injury and with onset of new symptoms. Imaging showed findings compatible with Wallerian degeneration (WD) above and below the level of the original injury. We review the pathogenesis of spinal cord WD and its implications.     

脊髓损伤动物模型的制备及神经功能评价

脊髓损伤（spinal cord injury,SCI）是医学界面临的难题和研究热点之一。脊髓损伤动物模型的制备对脊髓损伤相关基础研究具有重要意义。笔者现就目前国内外常用的脊髓损伤动物模型的制备及神经功能评价的方法综述如下。     

MR evaluation of wallerian degeneration of the pyramidal tract

This study is based on 135 magnetic resonance (MR) exams of 110 patients with wallerian degeneration of the pyramidal tract shown on MR images acquired on a mid field imaging scanner. The MR findings of wallerian degeneration were abnormal signal band along the course of the pyramidal tract and ipsilateral brain stem shrinkage. In all 110 cases an abnormal signal band was seen on T2-weighted spin-echo images, that is, a hypointense band in four exams between 30 days and 116 days after onset of symptoms, and hyperintense bands in 122 exams. The hyperintense signal on T2-weighted images was shown in most cases after 200 days from the onset. In one case a signal of the pyramidal tract showed a hyperintense band at 7 days, hypointense at 30 days, and hyperintense again at 123 days after onset. Sequential MR exams of another case showed gradual narrowing of the hyperintense signal band and progression of the ipsilateral brainstem shrinkage. The narrowing of the pyramidal tract and the ipsilateral brain stem shrinkage tended to be shown after 6 months from onset.(ABSTRACT TRUNCATED AT 250 WORDS)     

颈髓损伤后的低钠血症

低钠血症是颈髓损伤的严重并发症之一，最早由Hald报告，已有40年历史，如治疗不当，低钠血症则难以纠正，且可加重脊髓损伤或使已经恢复的神经功能再次丧失。以前，并未引起广泛的注意。近年来，颈髓损伤后水电解质紊乱尤其是低钠血症(其他如：低氯血症、代谢性酸中毒、高钙血症等)愈来愈受到重视。     

急性中央颈脊髓损伤

急性中央颈脊髓损伤是最常见的颈脊髓急性不完全性损伤。这一综合征主要临床特点为上肢运动功能受累明显、而下肢受累较轻或不受累、直肠膀胱功能障碍以及损伤平面以上感觉不同程度损害。急性中央颈脊髓损伤预后一般较好     

电刺激治疗与脊髓损伤

神经系统是通过生物电传导和整合等方式来传递信息，作出反应。脊髓损伤后上下神经元的联系出现障碍，使神经功能发生障碍。轴突的正确连接是功能恢复的基础，但轴突朝正确方向生长需要有局部信息来引导。电刺激治疗能否促进脊髓恢复，后期功能性电刺激神经假体能否改善瘫痪患者的运动状态，备受关注。     

Determining prognosis after spinal cord injury

INTRODUCTION: Disability following traumatic spine injury often requires assessment for judicial reasons. OBJECTIVE: To determine the optimum time to carry out a medico-legal evaluation. METHODS: Retrospective study (1995-2000) of patients with traumatic spine injury with a follow-up of five years. The American Spinal Injury Association (ASIA) scale was used to determine level and extent of the injury. Statistical analysis by SPSS 11.0. RESULTS AND DISCUSSION: 173 injuries were analyzed (39.3% ASIA A; 15.6% ASIA B; 29.47% ASIA C; 15.6% ASIA D). Neurological improvement was detected in 35.83%, more frequently in incomplete injuries. ASIA A injuries remained mainly complete from admission to discharge and in no case reached functional levels. Only a third of ASIA B patients showed improvement, of whom 33.3% were functional. Improvement in ASIA C patients was 76.4%, these and all ASIA D patients were functional on discharge. The condition a year after the injury remained unchanged in all cases, regardless of the extent of injury. Patients who showed improvement did so early on, mainly during hospitalization. CONCLUSIONS: The optimum time for evaluation of spinal cord injury for medicolegal purposes is at one year after the injury. In cases of complete injury, evaluation can be carried out on discharge with no need to wait for one year.     

脊髓损伤治疗的循证研究进展

脊髓损伤是骨科常见病,会对人体造成明显的功能障碍,严重影响患者的生活质量,同时也给患者家庭和社会带来巨大负担.脊髓损伤的治疗一直是热点和难点问题.目前有关其治疗的循证研究多集中于药物治疗、手术时机、手术方案及康复等方面.现阐述如下.     

Vascular remodeling after spinal cord injury

PURPOSE: Our purpose was to determine whether spinal cord injured (SCI) subjects have decreased femoral artery diameter and maximal hyperemic blood flow when expressed per unit of muscle volume compared with able-bodied (AB) individuals. A secondary purpose was to determine whether blood flow recovery rates were similar between groups. METHODS: Blood flow was measured in the femoral artery using Doppler ultrasound after distal thigh cuff occlusion of 4 and 10 min. Muscle mass of the lower leg was determined by magnetic resonance imaging (MRI). RESULTS: SCI individuals had smaller muscle cross-sectional areas (37%, P = 0.001) and volumes (38%, P = 0.001) than AB individuals. Furthermore, femoral artery diameter (0.76 +/- 0.14 vs 0.48 +/- 0.06 cm, AB vs SCI, P < 0.001) and femoral artery maximal blood flow (2050 +/- 520 vs 1220 +/- 240 mL x min-1, AB vs SCI, P < 0.001) were lower in SCI than AB individuals. Femoral artery diameter and maximal blood flow per unit muscle volume did not differ between SCI and AB individuals (P = 0.418 and P = 0.891, respectively). Blood flow recovery after ischemia was prolonged in SCI compared with AB individuals for both cuff durations (P = 0.048). CONCLUSIONS: In summary, femoral artery diameter and maximal hyperemic blood flow response per unit muscle volume are not different between SCI and AB individuals. Vascular atrophy after SCI appears to be closely linked to muscle atrophy. Furthermore, the SCI compared with AB individuals had a prolonged time to recovery, which may suggest decreased vessel reactivity.     

MRI of spinal cord and brain lesions in subacute combined degeneration

Subacute combined degeneration is a rare cause of demyelination of the dorsal and lateral columns of the spinal cord and even more rarely of the pyramidal and spinocerebellar tracts and cerebellum. We present the initial and follow-up MRI appearances in a patient with subacute combined degeneration of the spinal cord, brain stem and cerebellum, due to vitamin B₁₂ deficiency. The lesions in these structures were demonstrated clearly as pathologically high-signal areas on T2-weighted images. These lesions, except those of the brain stem and cerebellum, disappeared 4 months after therapy. MRI 14 months after the patient's discharge on vitamin B₁₂ therapy showed the same picture. Received: 24 July 1997 Accepted: 20 November 1997     

MRI对急性脊髓损伤的评价

目的 探讨MRI在评价急性脊髓损伤中的临床应用价值.方法 收集急性脊髓损伤患者50例,行同期X线片、CT和MRI检查,MRI检查应用1.5T超导型磁共振成像仪,采用自旋回波序列和快速自旋回波序列,常规矢状位及横轴位扫描,17例加扫冠状位.结果 脊髓水肿:MRI检出16例,CT检出4例;脊髓挫伤出血:MRI检出21例,CT检出11例;脊髓受压变形:MRI检出34例,CT检出15例;脊髓断裂:MRI检出10例,CT检出3例.X线片未检出上述脊髓损伤.结论 MRI对评估脊髓损伤明显优于X线片和CT扫描,是急性脊髓损伤的最佳检查与诊断方法.