胸腰椎骨折手术适应证及其远期疗效观察

目的 探讨胸腰椎骨折的手术适应下及后路椎管环形减压、椎体植骨的远期疗效。方法 1994－2000年，采用椎管环形减压，结合横突间、椎板间和经椎弓根椎体内植骨,治疗176例胸腰椎骨折。术前不同随访时间行CT检查，分别计算其伤椎椎管狭窄率，确定椎管矢状径的恢复程度，采用配对t检验方法进行统计学分析。结果 97例患者术后平均随访23．2个月，按美国脊髓损伤学会（ASIA）神经损伤分级标准评定，71例脊髓不完全性损伤患者，64例分别提高1－3级，7例无变化；26例完全性脊髓损伤患者部分神经根功能有所恢复。CT检查显示，术前伤椎椎管狭窄率平均44．7％，术后伤椎椎管减压充分，1年后出现椎管再塑形现象，再塑形的伤椎椎管管径与正常理论值比较，差异无显著性意义（P＞0．05）。结论 大部分脊髓不完全性损伤的椎体骨折骨折应采用.地无神经压迫症状的不稳定性爆裂型骨折，手术治疗是预防晚期并发症的有效方法。椎管环形减压后1年，椎管表现出自发再塑形现象，塑形后的椎管管径在正常理论值范围。经椎弓根椎体内植骨技术可预防术后椎体塌陷。     

Normal and degenerative posterior spinal structures: MR imaging

A retrospective study of the magnetic resonance (MR) images of the lumbar spines of 13 healthy subjects and 30 patients with degenerative changes was done. In the healthy subjects, the vertebral facets, thickness of the cartilage and ligamentum flavum, signal characteristics of the bone marrow, and size of the spinal canal were studied. In the patients with degenerative changes in one of these structures, MR images in the sagittal plane were useful in demonstrating hypertrophy of the ligamentum flavum or the vertebral facets, in grading the degree of foraminal stenosis, and in measuring the sagittal diameter of the spinal cord. MR images in the axial plane facilitated detailed analysis of the facet joint and more accurate measurements of the thickness of the ligamentum flavum and spinal canal diameter. MR images were compared with computed tomography scans in 12 patients.     

Cervical myelography with metrizamide (amipaque)

Summary Cervical myelography with metrizamide was performed in a series of 30 patients. Minor modifications to the conventional technique made it possible to carry out measurements of the sagittal diameter of the cord and to improve the opacification of the upper cervical —foramen magnum region. Computer tomography was performed with a head scanner within 1 h after the conventional examination, and the spinal cord surrounded by contrast medium was shown from C-3 to the foramen magnum region. Measurements of the sagittal diameter of the spinal canal and the cord at corresponding levels using the two methods showed good correlation.     

比率法判定颈椎管狭窄的应用价值

作者对经临床确诊为颈椎管狭窄的２００例影像学资料，包括Ｘ线平片和ＣＴ扫描片各１００份，测量Ｃ＿（４－５）椎管与椎体的矢状径与横径。将椎管矢状径为１１ｍｍ及其以下者（绝对值法）和椎管下矢径／椎体中矢径之比率值为０．７１及其以下者（比率法），暂作为颈椎管狭窄的判定标准。分析并比较两种方法对颈椎管狭窄的检出率。结果提示，比率法平片组与ＣＴ组均明显优于绝对值法。运用比率法诊断颈椎管狭窄，Ｘ线平片与ＣＴ扫描同样有效。     

Cervical spinal stenosis: determination with vertebral body ratio method

Transient bilateral sensory and motor symptoms after trauma, including complete paralysis, have been identified in patients with cervical spinal stenosis. Radiographs of 23 patient athletes with cervical spinal neurapraxia were used for measurement of the cervical spinal canal. Two methods of measurement were used. In the conventional method, sagittal diameter is measured from the posterior surface of the vertebral body to the nearest point of the corresponding laminar line. In the ratio method, the sagittal diameter of the spinal canal is divided by the sagittal diameter of the corresponding vertebral body. Results indicate the ratio method is reliable for determining cervical spinal stenosis and is independent of technical factor variables.     

Morphological analysis of the cervical spinal canal,dural tube and spinal cord in normal individuals using CT myelography

To verify the conventional concept of developmental stenosis of the cervical spinal canal, we performed a morphological analysis of the relations of the cervical spinal canal, dural tube and spinal cord in normal individuals. The sagittal diameter, area and circularity of the three structures, and the dispersion of each parameter, were examined on axial sections of CT myelograms of 36 normal subjects. The spinal canal was narrowest at C4, followed by C5, while the spinal cord was largest at C4/5. The area and circularity of the cervical spinal cord were not significantly correlated with any parameter of the spinal canal nor with the sagittal diameter and area of the dural tube at any level examined, and the spinal cord showed less individual variation than the bony canal. Compression of the spinal cord might be expected whenever the sagittal diameter of the spinal canal is below the lower limit of normal, that is about 12 mm on plain radiographs. Thus, we concluded that the concept of developmental stenosis of the cervical spinal canal was reasonable and acceptable.     

颈椎间盘突出的CT表现

本文报告37例颈椎间盘突出。CT图像上的直接征象为椎间盘向椎管内突入的软组织块影。间接征象是硬膜外脂肪、硬膜囊,蛛网膜下腔、脊髓和神经根鞘袖受压改变。椎间盘突出厚度与椎管矢状径之比称之为椎管狭窄率。脊髓受压程度与该率大小有关,当该率为19％左右时,没有或仅有下肢轻微不适;32％左右时,可有下肢无力、步行不便;48％左右时,步行困难或卧床不起。11mm可作为国人颈椎管矢状径的正常下限。     

Cervical myelography: survey of modes of practice and major complications

A total of 68 major complications of cervical myelography were reported by 220 neuroradiologists in a mail survey. Two-thirds of the complications were attributed to cervical spine hyperextension and one-third to lateral C1-2 puncture. Narrow sagittal diameter of the spinal canal and severe cervical spondylosis were frequent contributing factors to hyperextension injury of the cervical spinal cord. Clinical and radiographic premyelography screening is suggested, with magnetic resonance imaging performed first in patients with spinal canal stenosis, severe spondylosis, and/or myelopathy of any cause. Neck extension should be minimal during myelography. All C1-2 punctures should be monitored with lateral fluoroscopy for accurate needle positioning and prevention of contrast medium injection into the spinal cord.     

Magnetic resonance imaging of spinal cord syndromes

Thirty-four patients with intramedullary space-occupying lesions or cord compression syndromes were examined with a resistive and two different superconductive magnetic resonance (MR) imaging units. Studies were done primarily by the spin-echo (SE) technique and in the majority of patients different pulse sequences were used. Images with short echo-time (TE) and short recovery-time (TR) were best for demonstration of spinal cord anatomy, for depicting cystic portions in intramedullary tumours and for showing syringomyelia. Solid intramedullary tumours showed normal cord signal intensity. Images with prolonged TE and TR predominantly enhanced CSF signal intensity and, to a more considerable extent, solid intramedullary tumours. Thus, the diameter of the subarachnoid space and the presence of a solid intramedullary tumour, not concomitant with a significant enlargement of the spinal cord, could only be recognized on these prolonged SE images. Major advantages of MR in comparison to CT are that the spinal cord can be imaged in the sagittal plane and that beam hardening artifacts do not occur; in comparison to myelography the cord can be imaged directly by MR. Partial volume is a major limitation of MR, not only in the preferably applied sagittal plane. The choice of slice thickness adequate to the diameter of the lesion and straight positioning of the patient for sagittal single slice midline images are fundamental for reliable MR investigations. Another limitation to MR is that cortical bone gives no signal. The actual diameter of the spinal canal therefore cannot be correctly appreciated and consequently it was difficult or impossible to assess spinal stenosis.     

Cervical spinal stenosis with cord neurapraxia: evaluations and decisions regarding participation in athletics

Cervical spinal cord neurapraxia (CCN) leads to transient episodes ranging from paresthesia to paresis to plegia (complete paralysis), and occurs in athletes with some demonstrable degree of cervical spinal stenosis. Determination of spinal stenosis requires demonstrating a sagittal diameter of the spinal canal less than 14 mm from C4 to C6. Because radiologic techniques vary affecting the accuracy of this measure, a ratio method was developed comparing the spinal canal to the vertebral body width, demonstrating that a ratio of less than 0.8 is indicative of cervical spinal stenosis. Although this has high sensitivity (93%), the low predictive value of 0.2% makes this a poor screening tool for athletic participation. Further complicating the challenge of determining which athletes are at risk for quadriplegia are data showing that athletes who suffered permanent injury did not recall transient episodes of CCN, and conversely none of the athletes with CCN later developed permanent neurologic injury. Nevertheless, 56% of football athletes returning to sport after an episode of CCN experienced a recurrence as determined by survey data. Those with CCN and documented ligamentous instability, magnetic resonance imaging evidence of cord defects or swelling, neurologic symptoms or signs for greater than 36 hours, or more than one recurrence have an absolute contraindication.     

Cervical myelopathy: MRI evaluation of cord compression

In order to assess the consequences of cervical spinal cord compression in cervical myelopathy, MRI measurements of the sagittal diameter of the cervical spinal cord were obtained in 50 normal volunteers and 50 patients suffering from cervical myelopathy. Whatever the degree of stenosis, the values obtained in the latter group are significantly inferior to those of the normal control group (average mean diameter: normal group: 8.2 mm; cervical myelopathy: 6.2 mm).     

Myelographic findings in cervical spines without degenerative changes

Summary One hundred cervical myelographies in patients without degenerative changes on plain radiographs were evaluated. Pathologic changes were seen in 75 patients, most of them with congenital spinal canal stenosis and dural sac stenosis. Normal values for sagittal diameter of the dural sac from C2 to C6 were established. It was found that a quotient <0.9 between the sagittal diameter of the spinal canal and the midsagittal diameter of the vertebral body indicated congenital stenosis. It is concluded that plain radiographs of the cervical spine are unreliable in predicting the diagnostic value of cervical myelography.     

Lumbar spondylolysis without spondylolisthesis: recognition of isolated posterior element subluxation on sagittal MR.

PURPOSETo document the occurrence of isolated dorsal subluxation of posterior elements in cases of lumbar spondylolysis without spondylolisthesis both quantitatively (using spinal canal measurements) and qualitatively (by visual inspection) on sagittal MR images.METHODSRetrospective analysis identified 63 patients with lumbar spondylolysis (confirmed by CT or conventional radiography) who had undergone MR imaging. From these we identified 12 patients with pars interarticularis defects but no evidence of spondylolisthesis. Measurements of anteroposterior spinal canal diameters were performed in these 12 patients to ascertain whether the sagittal canal diameter at the level of the spondylolysis exceeded the normal range as determined from 100 control subjects.RESULTSIn 9 of 12 patients the spinal canal was abnormally widened at the level of the spondylolysis because of dorsal subluxation of posterior elements. In 5 of these patients, the subluxation was readily visible on midline sagittal MR images. In 4 patients, spinal canal measurements were necessary to document this phenomenon.CONCLUSIONIn the majority of patients with spondylolysis but without spondylolisthesis, sagittal MR images can show isolated dorsal subluxation of posterior spinal elements.     

Radiographic anatomy of the distal dural sac. A myelographic investigation of dimensions and termination.

A radio-anatomical study was performed of the distal dural sac (DS) in 121 patients subjected to myelography. In 83.4% the termination of the DS was located from the upper half of the S1-segment to the lower half of the S2-segment. In the remaining patients the dural terminations were more distally located. The average location of the DS-termination was higher than that found in a previous anatomic study. The inference is that in patients with low-back pain and sciatica, the DS tends to terminate at a higher spinal level than in a non-selected anatomic material. The caudal reduction in sagittal diameter of the DS was less than that of the frontal diameter of the sac. The linear diminution in cross-sectional area of the DS from the level of L3 towards the lumbo-sacral junction was not correlated with the degree of caudal extension of the DS into the sacrum. Thus the length of the DS and its transverse diameters are independent of each other. These results supported the view that the location of the termination of the DS (and hence that of the spinal cord) is not related to stenosis of the central spinal canal.     

颈后路单开门椎管扩大成形术治疗多节段脊髓型颈椎病

目的探讨颈后路单开门椎管扩大成形术治疗多节段脊髓型颈椎病的疗效及手术前后影像学变化。方法用颈后路单开门椎管扩大成形术治疗多节段脊髓型颈椎病病人68例,用JOA17分法评价术前,术后功能恢复及临床症状消失的情况,测量术前术后椎管矢状径变化。结果 68例患者均获随访,随访时间平均12.3个月,术后病人均获不同程度症状改善。术后颈椎椎管矢状径扩大明显。结论该术式治疗多节段脊髓型颈椎病具有操作简单、安全性高、疗效确切的优点,并且只有严谨操作和围术期处理,才能有效避免各种并发症的发生。早期手术可防止脊髓损伤继续加重。     

Forward shifting of posterior dural sac during flexion cervical magnetic resonance imaging in Hirayama disease: An initial study on normal subjects compared to patients with Hirayama disease

Objective

Forward shifting of the posterior cervical dural sac is the most important sign in diagnosing Hirayama disease but can also be seen in normal subjects, causing potential diagnostic dilemma. We aim to explore the degree of forward displacement of posterior dural sac in normal subjects compared to that with Hirayama disease.

Materials and methods

50 healthy male teenagers and 3 patients with Hirayama disease were recruited into the control group and patient group, respectively. MR imaging of the cervical spine was performed in both neutral and flexion positions for all subjects, with the following parameters measured: maximal distance of forward shifting of posterior dural sac, dimension of dural sac and spinal cord.

Results

Forward shifting of the posterior cervical dural sac was depicted in 46% of normal subjects upon flexion position but without associated cord compression due to intrinsic expansion of the spinal canal volume. This intrinsic compensatory mechanism was inadequate in diseased patients leading to cord compression with significant increment in ratio of anteroposterior diameter of forward displacement of posterior dural wall/anteroposterior diameter of spinal canal (“x/y”), and decrement in ratio of anteroposterior diameter of spinal cord/perpendicular transverse diameter of spinal cord (“a/b”).

Conclusion

Depicting of forward shifting of posterior dural sac alone on flexion position cannot reliably diagnose Hirayama disease, which should be established only if there is forward shifting of posterior dural sac, plus increased ratio of x/y and decreased ratio of a/b on flexion position from associated mass effect on the spinal cord.     

Volume fast spin-echo imaging of the cervical spine

RATIONALE AND OBJECTIVES: The authors prospectively evaluated a T2-weighted, three-dimensional (3D) volume, fast spin-echo (SE) pulse sequence in assessment of the cervical spine and compared it with standard imaging protocol. MATERIALS AND METHODS: Eighteen patients with neck pain underwent magnetic resonance (MR) imaging at 1.5 T with two-dimensional (2D) fast SE and axial 3D gradient-echo (GRE) protocols and with an additional sagittal T2-weighted volume fast SE protocol. The spinal cord and canal, neural foramina, and intervertebral disks were assessed by two neuroradiologists, and the results were compared with reports from the standard protocol. The quality of the partition (direct sagittal) and reconstructed images were evaluated. RESULTS: No differences existed in the assessment of spinal cord disease or disk herniation with 2D fast SE and volume fast SE imaging. Some mild variation occurred in assessment of the neural foramina. Partition images demonstrated a high level of resolution and contrast, while reconstructed images had consistently lower quality. However, this did not impede detection and grading of disk or spinal abnormalities, which were adequately shown on volume fast SE sagittal images. Neural foramina were well demonstrated on axial reconstructions from volume fast SE imaging. CONCLUSION: Volume fast SE imaging provides information about the spinal cord, canal, disks, and neural foramina that is comparable to the information provided by routine imaging. Its thinner sections and multiplanar reconstruction capability are advantages over 2D imaging. Its greater tissue contrast with better visualization of the cervical cord, greater signal-to-noise ratio, and less susceptibility artifact are advantages over 3D GRE imaging.     

扩散加权成像在脊髓型颈椎病中的应用

目的:研究扩散加权成像(DWI)在脊髓型颈椎病(CSM)中的应用价值。方法:30例临床及影像学证实为CSM患者,行颈髓MRI和扩散加权成像,分析病变表现并测量其ADC值。结果:30例中除2例因伪影明显未行ADC值测量外,余28例均成功行DWI及ADC值测量。CSM的MRI主要表现为颈椎曲度异常、椎体骨质增生、椎间盘突出、后纵韧带及黄韧带增厚等,相应部位的脊髓均有不同程度的受压改变,伴有椎管狭窄者20例。T2WI脊髓受压部位出现高信号者18例,其中16例DWI相应部位均表现为ADC值增高,2例表现为ADC值略减低;10例T2WI未见异常信号者中有5例亦表现为脊髓受压部位不同程度的ADC值增高。3例手术后复查DWI显示病变部位ADC值不同程度减低。结论:DWI对CSM的早期诊断具有较高的敏感性,且可以在手术疗效监测方面发挥重要作用。     

Spinal stenosis subsequent to juvenile lumbar osteochondrosis

This paper describes eight patients with spinal stenosis associated with marked osteochondrous changes in the vertebral bodies due to juvenile lumbar osteochondrosis (Scheuermann's disease). In no case was the midsagittal or interpedicular diameter of the spinal canal indicative of bony stenosis. On the other hand, in the myelograms the sagittal diameter of the dural sac was in all cases significantly narrowed, a diagnostic sign of central spinal stenosis. Therefore, myelography should always be contemplated when osteochondrous changes are present and spinal stenosis is suspected clinically regardless of whether the spinal canal diameters are normal in plain films.