陈旧性Denis Ⅱ型骶骨骨折合并骶神经损伤的诊断与治疗

目的：探讨陈旧性Denis Ⅱ型骶骨骨折合并骶神经损伤的诊断及手术方法。方法：取60具骶骨干标本及26具完整骨盆标本，测量S1棘突与S1后孔同位置关系、骶前区血管、骶神经及梨状肌之间关系；对14例陈旧性DenisⅡ型骶骨骨折合并骶神经损伤患者，在常规骨盆X线片，CT，螺旋CT三维重建的同时，又采用显示骶神经全长的骶骨斜冠状位MR扫描，观察神经走向及眦领关系。11例行自行设计的后略骶神经管扩大减压术，3例行非手术治疗。结果：S1棘突于S1后孔中上1/3者占90%，骶前区主要血管有骶外侧动静脉和骶外侧血管、骶正中血管及臀上血管进入骶前孔的分支。血管位于骶丛神经腹侧，骶外侧斑管距离S1前孔大于10mm，S2前孔大于5mm。骶骨斜冠状位MR扫描可以显示骶神经全长及周围眦领关系。骶神经损伤时，发现有神经根走行改变(13例），损伤处神经很周围脂肪消失（11例），神经根管狭窄(10例)。14例均获得随访。随访时间6--12个月。平均7.1个月，术后改善情况，优9例，无变化1例。结论螺旋CT三维重建及骶骨斜冠状位MR扫描对于骶神经损伤的定位及定性诊断有重要价值。后路骶神经管扩大减压术是针对骶神经管、骶前孔处神经损伤的较理想手术方法。     

脊柱原发性肿瘤的手术治疗策略

目的 回顾性研究对脊柱原发性肿瘤患者应用多种入路实施手术治疗的效果及并发症。探讨脊柱原发性肿瘤的手术治疗策略。方法 自1998年7月至2005年7月，共收治脊柱原发性肿瘤患者135例。其中，骨髓瘤25例，神经纤维瘤、神经鞘瘤23例，巨细胞瘤17例，血管瘤15例，淋巴瘤9例，软骨肉瘤7例，骨母细胞瘤6例，嗜酸性肉芽肿6例，尤文肉瘤5例，动脉瘤样骨囊肿4例，粒细胞肉瘤4例，骨肉瘤3例，恶性纤维组织细胞瘤3例i血管内皮瘤2例，骨纤维异样增殖症2例，骨软骨瘤2例，脊索瘤2例。病变累及颈椎13例，胸椎79例，腰椎43例。出现神经系统受累者92例，其中Frankel分级A、B级9例，C、D级83例；无神经系统受累者43例。前后路联合手术切除肿瘤18例，经后路侧前方手术13例，经前路切除肿瘤73例，经后路切除肿瘤31例。结果 135例患者中，126例（93.3％）术后疼痛得到不同程度的缓解，9例术后疼痛无明显减轻。92例术前有神经系统受累的患者中，86例术后麻痹症状得到不同程度的缓解。在随访期内未见严重并发症。11例患者术后出现脑脊液漏，经应用抗生素及抬高床尾治疗后愈合。3例应急性溃疡患者，经输血及抗酸药治疗溃疡愈合。皮下气肿3例，伤口浅表感染3例，神经根损伤2例，内固定物松脱2例，瘫痪加重1例。结论 对于脊柱巨细胞瘤或软骨肉瘤等恶性肿瘤破坏单个或相邻的两个脊椎时，应采用前后路联合手术切除肿瘤。术前根据肿瘤的Tomita或WBB分期设计手术方案，合理切除肿瘤，降低术后复发率。     

Limited proteolysis of single-chain tetanus toxin by tissue enzymes,in cultured brain tissue and during retrograde axonal to the spinal cord

Summary Single-chain toxin was investigated in vitro and in vivo for limited proteolysis into the fully active two-chain toxin. Plasmin from serum, elastase and gelatinase from leucocytes, as well as clostripain from C. histolyticum cleaved single-chain toxin and increased by that way its ability to inhibit [³H]noradrenaline release in vitro. Cultured mouse brain generated fragments from ¹²⁵I-single-chain toxin which were cell-associated. Some of them comigrated in electrophoresis with light and heavy chain after mercaptolysis. When injected i. v. into rats, ¹²⁵I-single-chain-toxin disappeared from the blood with a half-life of about 11 h without signs of nicking. However, after its injection into the triceps surae muscle both single- and two-chain toxin were found in the ipsilateral ventral horn of the spinal cord. Thus single-chain toxin is subjected to limited proteolysis by enzymes involved in tissue damage, by cultured brain tissue, and during or after its retrograde axonal transport to the spinal cord. Limited proteolysis is necessary for the release of the light chain known to mediate the action of toxin on several systems.     

Gd-DTPA-enhanced MR in thoracic disc herniations

Summary The Gd-DTPA-enhanced magnetic resonance findings in two patients with herniated thoracic intervertebral discs are reported. The first patient was a 56-year-old woman with a small subligamentous T6-7 disc herniation, slightly lateralized to the right. The second patient was a 51-year-old man with a central and right posterolateral disc herniation, including a large calcified fragment, at the T8-9 level. The nonenhanced MR examination revealed the presence of an extradural mass lesion in both patients, impinging upon the dural sac and compressing and displacing the spinal cord posteriorly. The lesion was slightly hypointense on both T1- and T2-weighted spin echo sequences. Following intravenous injection of Gd-DTPA in a dosage of 0.1 mmol/kg body weight, enhancement of the posterior longitudinal ligament was noted and triangular areas of contrast uptake were seen to occur in the epidural space above and below the herniated disc. At surgery, they were found to correspond to dilated and congested epidural veins.     

Repetitive lifting and spinal shrinkage, effects of age and lifting technique

The assumed advantages of the so-called leg-lifting technique over the back-lifting technique are still the subject of much debate. The present study was aimed at studying the consequences of performing both lifting techniques on net lumbar moments and spinal shrinkage. Furthermore, the relation between age and spinal shrinkage was studied. Five subjects approximately 40 years old and six subjects 20 years old performed six 5-min bouts of repetitive lifting using each technique on a separate day. Net lumbar moments were calculated using a two-dimensional dynamic linked segment model. Spinal shrinkage was measured at T₁₂ and at the head after each bout of lifting and every 5 min during 1 h preceding the lifting bouts. The peak moments were marginally but significantly higher in the leg-lift. No differences in mean moments and shrinkage between lifting techniques were found. The shrinkage after the back-lift was more pronounced in the older subjects and a similar tendency was found after the leg-lift. The creep rate, i.e. the rate at which the shrinkage approaches its equilibrium was higher in the older subjects. No clear relations of anthropometrical variables and net moments with shrinkage was found. The common advice of using a leg-lift rather than a back-lift was not supported by the present study. Both the mechanical load on the low back (net moments) and the resulting shrinkage show considerable interindividual variation, the causes of which need further elucidation.

The leg-lifting technique is still widely advocated, thought its merits from a biomechanical point of view have been questioned. In this study spinal shrinkage and lumbar moments calculated by means of a dynamic linked segment model are used to compare the leg-lift to the more commonly used back-lift.     

Discrimination of spinal fracture with various bone mineral measurements

For several different bone mineral measurements and various skeletal sites, we compared capability to discriminate between women in various age decades with and without spinal fracture, and attempted to identify the most effective cutoff level in discrimination of spinal fracture. The subjects were 88 women aged 50–59 years (including 32 with fracture), 95 women aged 60–69 years (including 54 with fracture), and 34 women aged 70–79 years (including 18 with fracture). Spinal trabecular and cortical bone mineral density (BMD) were measured using quantitative computed tomography (CT), and spinal, radial (ultra-distal, 10% distal and 33% distal), and calcaneal BMD were measured by dual X-ray absorptiometry. These BMD values were obtained in each subject on the same day. Three statistical techniques—Student's t-test, the logistic regression analysis, and the receiver operating characteristics (ROC) analysis— were applied and accuracy was calculated using the various cutoff values. The capability to discriminate between women with and those without fracture using these BMD values was different among the three age groups. In women aged 50–59 and 60–69 years, all measurements showed good capabilities for discriminating women with fracture. In women aged 70–79 years, these measurements showed lower capability than in those aged 50–59 and 60–69 years, but among them, the calcaneal and ultradistal radial BMD showed relatively good capability. The 10% and 33% distal radial BMD values were not useful in the detection of the high risk women with fracture. The cutoff BMD values for discrimination of women with fracture varied according to the sites and methods of measurement. For each specific age group, the most suitable measurement methods and the appropriate skeletal sites should be considered, and the effective cutoff values to discriminate those with fracture may differ according to the measurement methods, the skeletal sites examined, and age. Received: 5 February 1996 / Accepted: 18 June 1996     

Dynamic gadolinium-enhanced MRI in the detection of spinal arteriovenous malformations

Arteriovenous fistulae and malformations (AVFs and AVMs) of the spinal cord are rare, potentially treatable causes of progressive disability. Although a variety of MRI abnormalities has been described, the diagnosis rests on the findings on selective spinal angiography.Collecting T2^*-weighted MR images during the passage of a gadolinium bolus gives information about perfusion and blood volume. We carried out dynamic MRI in seven patients with vascular abnormalities (5 dural AVFs, 1 intramedullary AVM, 1 cryptic angioma) and in two patients without an AVM. High resolution T1- and T2-weighted sagittal images of the whole spinal cord were first obtained using a multiarray receiver coil. Sagittal radiofrequency spoilt gradient echo images (GE34/25, flip angle 10⁰) were then obtained during bolus injection of gadolinium-DTPA. Abnormalities were seen in all seven patients with AVFs or AVMs. In the patient with an intramedullary AVM and four of the five with dural AVFs transient signal reduction was seen within the perimedullary venous plexus during passage of the bolus. The findings correlated well with those from selective spinal angiography. We conclude that dynamic MRI offers a useful adjunct to angiography and may localise an arteriovenous shunt when conventional MRI fails to do so. In combination with high-resolution imaging of the entire spinal cord the technique may make myelography redundant; it is simple, well tolerated and can be carried out without significant time penalty.     

Use of gadolinium chelates in MR imaging of the spine

Spinal disease can be divided into intramedullary, extramedullary-intradural, and extradural compartments. In the cord (intramedullary compartment), gadolinium chelates are useful to diagnose primary and metastatic tumors, inflammation, and demyelination, and to evaluate syringomyelia when a Chiari I malformation is not present. In the extra-medulullary-intradural compartment, gadolinium chelates are useful for the diagnosis of drop metastases, meningiomas, and schwannomas. In the extradural compartment, gadolinium chelates are most useful to distinguish recurrent disc herniation from epidural fibrosis in the postoperative back and may be useful to diagnosis the soft tissue component of osseous metastases.     

Scintigraphic visualization of intrathecal liposome biodistribution

Background: Liposomes containing local anaesthetics have been administered intrathecally and in the epidural space. Poor attention has been given to the pharmacokinetics of liposomes as drug carriers. Therefore, we observed the biodistribution of liposomes after intrathecal injection in rats by scintigraphic imaging during 24 h.
Methods: We administered ⁹⁹Tc-labeled multilamellar (MLV) and small unilamellar vesicles (SUV) of defined size and volume dispersities into the cerebrospinal fluid at the lumbar level. Those vesicles were free of contamination by radiolabeled colloids as visualized by light and electron microscopy and of neurotoxic products from phosphatidylcholine hydrolysis and peroxidation, both during the preparation process and after 24 h incubation in cerebrospinal fluid at 37°C in vitro.
Results: SUV immediately diffused from the lumbar site of injection to the head and were cleared between 1 and 24 h after injection. MLV were cleared more slowly from the spinal space and appeared in the head region 1 h after injection where they accumulated up to 24 h. These differences were explained in terms of vesicle sizes and volumes. SUV with 0.05 μm diameters were rapidly absorbed into the blood through the arachnoid granulations. In contrast, particles larger than the upper size limit of the arachnoid granulations permeability (±8 μm) could accumulate in the head with a slow elimination rate.
Conclusion: This difference in clearance from the intrathecal space outlines the importance of defining the size of the liposomes, the distribution of a tracer or a drug inside the liposomal preparation, the chemical stability and the absence of toxic degradation products of liposome formulations before clinical use.