Anterior Spinal Cord Ischemia after Infrainguinal Bypass Surgery

Morbidity of infrainguinal bypass surgery is mostly related to cardiac complication, graft thrombosis, and wound infections. Neurologic complications in these patients are unusual and generally related to traumatic peripheral nerve injury or ischemia. Anterior spinal cord ischemia, manifest clinically as flaccid paraplegia or lower extremity paraparesis, is a complication usually associated with aortic surgery. Reported here is a case of an 81-year-old male who developed spinal cord ischemia after infrainguinal bypass under epidural anesthesia.     

Early Protective Effects of Iloprost after Experimental Spinal Cord Ischemia in Rabbits

The potential role of Iloprost, a stable analogue of prostocyclin, in treating spinal cord ischemia was investigated in rabbits subjected to aortic occlusion for 15 minutes. Ten adult rabbits weighing 2-2.5 kg received an intravenous infusion of saline (SF) as a control group and 14 rabbits received an intravenous infusion of Iloprost, 25 microg/kg/h. Iloprost infusion was started immediately after clamping of the aorta and continued 60 minutes thereafter. Cortical somatosensorial evoked potentials (CSEP) were recorded during the pre-ischemic period as a baseline and post-ischemic readings were taken at 15, 30 and 60 minutes. There was no statistically significant difference between CSEP of the saline and Iloprost treated groups (p < 0.05). All animals were examined neurologically by using a modification of Tarlov scale and all subjects were then deeply anesthetized and their spinal cords were removed for light and electron microscopic examinations at 24 h after spinal cord ischemia. In order to obtain an accurate comparison of ultrastructural changes between saline treated and Iloprost treated groups, a grading scale was performed. The light microscopic and ultrastructural analysis of the Iloprost treated group revealed that there was moderate protection of the myelin and axons and edema was attenuated. Findings of this study suggest that Iloprost exerts a protective effect on spinal cord ischemia. However, further studies are needed to reveal possible mechanisms of protection provided by Iloprost.     

Reevaluation of Gray and White Matter Injury after Spinal Cord Ischemia in Rabbits

Background: Although gray matter injury has been well characterized, the available data on white matter injury after spinal cord ischemia (SCI) in rabbits are limited. The current study was conducted to investigate the evolution of ischemia induced injury to gray and white matter and to correlate this damage to hind-limb motor function in rabbits subjected to SCI.

Methods: Thirty-eight rabbits were randomly assigned to 24-h, 4-day, or 14-day reperfusion groups or a sham group (n = 9 or 10 per group). SCI was induced by occlusion of the infrarenal aorta for 16 min. Hind-limb motor function was assessed using the Tarlov scale (0 = paraplegia, 4 = normal). The gray matter damage was assessed on the basis of the number of normal neurons in the anterior spinal cord. White matter damage was assessed on the basis of the extent of vacuolation and accumulation of amyloid precursor protein immunoreactivity.

Results: Tarlov scores gradually decreased and reached a nadir 14 days after reperfusion. There were no significant differences in the number of normal neurons among the 24-h, 4-day, and 14-day groups. The extent of vacuolation, expressed as a percent of total white matter area, was significantly greater in the 4-day and 14-day groups in comparison with the sham group. By contrast, there was no difference in vacuolation between the sham and 24-h groups. Amyloid precursor protein immunoreactivity was greater in the 4-day and 14-day groups.     

Cyclooxygenase-1 in the Spinal Cord Is Altered after Peripheral Nerve Injury

Background: The mechanisms underlying neuropathic pain are incompletely understood and its treatment is often unsatisfactory. Spinal cyclooxygenase-2 (COX-2) expression is upregulated after peripheral inflammation, associated with spinal prostaglandin production leading to central sensitization, but the role of COX isoenzymes in sensitization after nerve injury is less well characterized. The current study was undertaken to determine whether COX-1 was altered in this model.

Methods: Male rats underwent partial sciatic nerve transsection (PSNT) or L5-L6 spinal nerve ligation (SNL). Four weeks after PSNT and 4 h, 4 days, or 2 weeks after SNL, COX-1 immunohistochemistry was performed on the L2-S2 spinal cord.

Results: COX-1 immunoreactivity (COX-1-IR) was unaffected 4 h after SNL. In contrast, 4 days after SNL, the number of COX-1-IR cells increased in the ipsilateral spinal cord. COX-1-IR increased in cells with glial morphology in the superficial laminae, but decreased in the rest of the ipsilateral spinal cord 4 weeks after PSNT and 2 weeks after SNL. These changes in immunostaining were greatest at the L5 level.     

The Effect of Graded Postischemic Spinal Cord Hypothermia on Neurological Outcome and Histopathology after Transient Spinal Ischemia in Rat

Background: Previous data have shown that postischemic brain hypothermia is protective. The authors evaluated the effect of postischemic spinal hypothermia on neurologic function and spinal histopathologic indices after aortic occlusion in the rat.

Methods: Spinal ischemia was induced by aortic occlusion lasting 10 min. After ischemia, spinal hypothermia was induced using a subcutaneous heat exchanger. Three studies were conducted. In the first study, the intrathecal temperature was decreased to 34, 30, or 27 [degree sign]C for 2 h beginning with initial reperfusion. In the second study, hypothermia (target intrathecal temperature 27 [degree sign]C) was initiated with reflow and maintained for 15 or 120 min. In the third study, the intrathecal temperature was decreased to 27 [degree sign]C for 2 h starting 5, 60, or 120 min after normothermic reperfusion. Animals survived for 2 or 3 days, at which time they were examined and perfusion fixed with 4% paraformaldehyde.

Results: Normothermic ischemia followed by normothermic reflow resulted in spastic paraplegia and spinal neuronal degeneration. Immediate postischemic hypothermia (27 [degree sign]C for 2 h) resulted in decreasing motor dysfunction. Incomplete protection was noted at 34 [degree sign]C. Fifteen minutes of immediate cooling (27 [degree sign]C) also provided significant protection. Delay of onset of post-reflow hypothermia (27 [degree sign]C) by 5 min or more failed to provide protection. Histopathologic analysis revealed temperature-dependent suppression of spinal neurodegeneration, with no effect of delayed cooling.     

应用中医传感针观察伤段脊髓氧分压的变化

目的：探讨应用中医传感针观察脊髓损伤（SCI）后伤段脊髓氧分压的变化及其与病理变化、神经功能损害的关系。方法：改变Allen法致伤大鼠脊髓，于伤前和伤后1／2、1、3、6、24、72、168h，用中医传感针技术测量脊髓氧分压，应用光、电镜观察脊髓病理变化，应用斜板试验评价大鼠运动功能。结果：SCI后伤段脊髓氧分压明显下降（P＜0．01），与病理变化及神经功能损害的发生发展一致。结论：中医传感针可应用于测量SCI后脊髓氧分压；脊髓氧分压是脊髓损伤研究中的重要观察指标。     

TMS—MEP监测脊髓缺血性损伤的实验研究

为观察经颅磁刺激的不同刺激量和脊髓缺血性损伤对运动诱发电位的影响，采用兔脊髓可逆性缺血损伤模型进行磁刺激运动诱发电位（ＴＭＳ－ＭＥＰ）监测。发现在４０％～８０％的刺激量时，ＭＥＰ相对稳定。脊髓缺血损伤后ＭＥＰ潜伏期延长或消失，恢复血供后ＭＥＰ先于后肢运动功能恢复，至４～６小时完全恢复正常，当脊髓缺血后２４小时出现继发性损伤时，ＭＥＰ再次出现异常，ＭＥＰ的表现和后肢运动功能变化及病理改变相一致。证实ＴＭＳ－ＭＥＰ可敏感而准确的反映脊髓缺血后改变，可用于监测脊髓的缺血性损伤。     

Early Trauma Indicators and Rehabilitation Outcomes in Traumatic Spinal Cord Injury

Objectives:To investigate the relationship between early trauma indicators and neurologic recovery after traumatic SCI using standardized outcome measures from the ISNCSCI examination and standardized functional outcome measures for rehabilitation populations.Methods:This is a retrospective review of merged, prospectively collected, multicenter data from the Spinal Cord Injury Model Systems (SCIMS) database and institutional trauma databases from five academic medical centers across the United States. Functional status at inpatient rehabilitation discharge and change in severity and level of injury from initial SCI to inpatient rehabilitation discharge were analyzed to assess neurologic recovery for patients with traumatic SCI. Linear and logistic regression with multiple imputation were used for the analyses.Results:A total of 209 patients were identified. Mean age at injury was 47.2 ± 18.9 years, 72.4% were male, 22.4% of patients had complete injuries at presentation to the emergency department (ED), and most patients were admitted with cervical SCI. Mean systolic blood pressure (SBP) was 124.1 ± 29.6 mm Hg, mean ED heart rate was 83.7 ± 19.9 bpm, mean O2 saturation was 96.8% ± 4.0%, and mean Glasgow Coma Scale (GCS) score was 13.3 ± 3.9. The average Injury Severity Score (ISS) in this population was 22.4. Linear regression analyses showed that rehabilitation discharge motor FIM was predicted by motor FIM on admission and ISS. Requiring ventilatory support on ED presentation was negatively associated with improvement of ASIA Impairment Scale (AIS) grade at rehabilitation discharge compared with AIS grade after initial injury. Emergency room physiologic measures (SBP, pulse, oxygen saturation) did not predict discharge motor FIM or improvement in AIS grade or neurological level of injury.Conclusion:Our study showed a positive association between discharge FIM and ISS and a negative association between ventilatory support at ED presentation and AIS improvement. The absence of any significant association between other physiologic or clinical variables at ED presentation with rehabilitation outcomes suggests important areas for future clinical research.     

脊髓前动脉损伤后脊髓病理演变的实验研究

目的观察脊髓前动脉损伤后脊髓组织形态学演变过程,研究病理机制.方法以家犬为实验模型,损伤脊髓前动脉后进行肉眼、光镜和电镜动态观察,定量测定坏死神经元.结果脊髓前动脉损伤2h运动神经元变性,轴索病变,6h神经元坏死,24h脊髓水肿达到高峰,7d髓内出血最明显.在脊髓前动脉损伤节段,24h 30%～40%的运动神经元坏死,3d达80%,7d以后95%以上.病变均位于脊髓2/3.脊髓前动脉损伤节段变性坏死最严重,相邻节段其次,尾侧脊髓坏死量逐渐减少.结论脊髓前动脉损伤后脊髓缺血性病变是渐进和不可逆的,可引起广泛节段脊髓病变.     

椎板成形术在椎管内肿瘤手术中的应用

目的 探讨棘突椎板复合体回植、钛板固定在椎管内肿瘤切除术中的应用价值.方法 2009年11月～2010年7月,对22例颈、胸椎的椎管内肿瘤(长3～11 cm,平均4.3 cm)采用磨钻沿关节突内侧2～3 mm磨开两侧的椎板,将棘突椎板复合体完整取下,处理完椎管内肿瘤后再将棘突椎板复合体原位回植,钛板固定,完成椎管成形....