Diagnostic perspectives of mobile radiographic computerized tomography]

The authors assess mobile methods of x-ray computer-aided tomography (CAT) and suggest an organization and methodological scheme of its application. Their program of the first and up to now the only one in this country mobile CAT device is based on the new principles of mobile CAT application. It is realized in special hospitals of large regions, where the patients with the optimal indications for CAT are assembled. Over 15,000 examinations were carried out with the use of the suggested CAT program over 4 years, that resulted in detection of 1295 brain tumors, 804 cases with neoplastic involvement of the abdominal cavity and the retroperitoneal space. The authors claim that wide application of mobile CAT devices according to the program they suggest will help decide the problem of unavailability of such examinations, for it will rule out the principal cause of this unavailability--economic problems arising because of high price of this equipment. One mobile device may replace 3 permanent CAT devices, if used according to the program suggested by the authors.     

Superiority of magnetic resonance imaging (MRI) over computerized tomography (CT) in diagnosis of hypopituitarism]

Hypopituitarism can be a result of various lesions of hypothalamus, pituitary stalk, or of the pituitary gland itself. The aim of the study was to assess the value of CT and MRI examinations in determination of the cause of hypopituitarism. Seventeen patients with hypopituitarism (9 women and 8 men) aged 22 to 61 years have been examined. In three cases growth deficiency was observed, 4 women had galactorrhoea, 4 patients had diabetes insipidus, 16 patients had supra-adrenal insufficiency, 14 had signs of hypogonadism and 10 hypothyroidism. In each case plasma concentrations of LH, FSH, PRL, TSH, alpha-subunit, ACTH before and after appropriate stimulation with TRH, metoclopramid, LH-RH, GRF or metyrapon were determined with RIA. Every patient was examined both with CT and MRI (0.5 T Toshiba MRT 50a). All 17 patients had abnormal MR images of hypothalamo-pituitary area, while only 10 of them had abnormalities in their CT scans. In remaining 7 patients the MRI revealed: three cases of congenital malformation of hypophyseal stalk, two cases of empty sella, one posttraumatic lesion of the stalk and one case of granulomatous infiltration of the stalk. We found MRI superior to CT in establishing the case of hypopituitarism.     

Disseminated pulmonary tuberculosis: significance of high-resolution computerized tomography]

Clinical and X-Ray studies were performed in 85 patients with disseminated pulmonary tuberculosis. All the patients underwent routine computerized tomography (CT) and high-resolution CT. According to the pathogenetic process, the authors identified hematogenic (n = 38), lymphogenic (n = 19), bronchogenic (n = 18) and mixed (n = 10) disseminations. High-resolution CT was found to have great advantages in detecting various types of tuberculous disseminations and in assessing the pattern of pulmonary abnormalities. Disseminated tuberculosis was revealed in 7 patients who had no pathological changes on routine lung X-ray films. The specific signs of hematogenic, lymphogenic disseminations and bronchgenic inoculations were identified in other forms of pulmonary tuberculosis. CT symptomatology is shown to be determined by the pathogenetic variant of its development and the stage of the process. Small focal changes in the lung were prevalent in patients with acute and subacute hematogenic forms of the disease. Infiltrates with decay cavities, thin-wall caverns, emphysema and bronchoectases were detected over the chronic course. Lymphogenic disseminations were characterized by the predominance of interstitial changes along with multiple minor foci. High-resolution CT had advantages in identifying decay cavities, signs of fibrosis and in evaluating mediastinal lymph nodes. CT data are of great significance for differential diagnosis of disseminated tuberculosis with lung metastases and diffuse interstitial diseases.     

Increase in facet joint loading after nucleotomy in the human lumbar spine

Low-back pain has been related to degenerative changes after nucleotomy. Although several etiologies for pain after nucleotomy have been proposed, there is evidence of pain arising in the facet joints in general, which may be related to changes in load transfer. This study addresses the effect of nucleotomy on facet joint loading.     

The extent of temperature sense and pain appreciation recovery in the dermatomes of the cauda equina roots after surgery for lumbar intervertebral disk herniation

Temperature sense and pain appreciation in the dermatomes of the cauda equina roots were estimated in patients with lumbar intervertebral disk hernias before surgery, as well as immediately and long after surgery for disk herniation. Before surgery, the temperature sense and pain appreciation were impaired not only in the dermatome of the compressed root, but also in the dermatomes located proximal and distal to it. The temperature sense was impaired more severely. The recovery of the temperature sense and pain appreciation in the dermatomes of the cauda equina roots after surgery is limited, especially in the region innervated by the compressed root. Positive changes in temperature sense and pain appreciation in different zones examined soon after surgery were observed, on average, in 55% of cases, whereas delayed positive changes were detected only in 36% of the patients. Pain appreciation (in tests with heat pain) both immediately and long after surgery was improved to a higher degree.     

Kinematics and muscle activities of the lumbar spine during and after working in stooped postures

Existing biomechanical evidence suggests mechanisms of low back injuries and disorders associated with prolonged stooping. However, no research has tested realistic and more natural stooped work conditions with human subjects in the investigation of the biomechanical responses of the low back in prolonged stooping. The current study was aimed to explore various biomechanical responses of the low back in more realistic and work-related loading and posture conditions of prolonged stooping. Twenty two subjects performed stooped work tasks for 7 min with periodic micro-breaks in upright standing, and various measures for assessing biomechanical responses of the low back were obtained before, during and immediately after the stooped work period. Study results found significant increases (p < 0.05) in the range of lumbar flexion and myoelectric activation of the low back muscles after the stooped work period. During stooped work, the low back extensor muscles did not show flexion–relaxation. It could be concluded that the natural and unrestricted stooped work conditions produced similar viscoelastic responses of the low back to what more severe stooping conditions with posture restrictions did in previous research, but could be more fatigue-prone due to low but consistent activation of the low back extensor muscles during stooped work activities.     

腰椎后路手术肠道菌群变化的研究

目的探讨腰椎后路手术患者肠道菌群的变化以期更合理的指导临床治疗。方法选择58例腰椎后路手术患者,出现肠道菌群失调症者38例,未出现肠道菌群失调症的20例作为对照组。在腰椎后路手术后,分别取2组患者自然排出的新鲜粪便10 g,采用定性定量检测比较2组患者肠道主要菌群差异及B/E值。肠道菌群失调症患者且与手术前自然排出的新鲜粪便进行相同比较。结果试验组肠道的双歧杆菌、类杆菌数量及B/E值较对照组均减少,分别是:9.21±0.65 vs 10.12±0.85;10.02±0.45 vs 10.23±0.45;1.05±0.17 vs 6.99±1.24,差异有统计学意义(P<0.05);而肠杆菌、肠球菌数量较对照组增加,分别是:9.11±1.09 vs 8.55±0.89;7.80±1.02vs 7.29±0.98,差异有统计学意义(P<0.05)。小梭菌、乳杆菌与对照组相比较,差异无统计学意义(P>0.05)。肠道菌群失调症患者与手术前进行比较,差异无统计学意义(P>0.05)。结论腰椎后路手术出现肠道菌群失调患者专性厌氧菌减少,条件致病菌增加,肠道微生物定植抗力下降。正确及时地去除病因,尽可能地采取微创手术技术,减少医源性损伤,调整机体免疫功能,纠正营养不良,合理使用抗生素是解决腰椎后路手术患者肠道功能障碍的有效办法。     

Computed tomography in the evaluation of tumor regression after neoadjuvant therapy: X-ray surgery and X-ray morphological comparisons

An analysis was made of chest computed tomograms of 38 small-cell lung cancer patients subjected to radical surgical treatment after neoadjuvant therapy. CT data were compared with the findings of macro- and microscopic examination of surgical specimens. In 24 (63.2%) patients, computed tomograms made before surgery showed complete tumor response confirmed by gross examination in 22 (96.1%) of them. However, microscopic examination found cancer cells in 8 (33.3%) patients. In 2 (8.3%) patients, small residual tumors could be detected by sight, which was confirmed by pathological examination. In 14 (36.8%) patients with partial response, radiological and gross examination findings fully coincided. Nevertheless, in 2 (14.3%) cases the "residual tumor" appeared to be a segment of fibrocicatrical tissue under pathological examination. On the basis of the CT findings the values of diagnostic sensitivity, accuracy and specificity in tumor response evaluation were calculated which made up 87.5%, 68.4% and 54.5% respectively. With sufficiently high sensitivity, CT specificity is low. CT makes it possible to objectively define the response of small-cell lung cancer to neoadjuvant therapy. However, the conclusion about complete response to the treatment can be made only on the basis of a comprehensive evaluation of the results of all available investigation methods and pathological examination.     

Use of high resolution algorithm in computerized tomography of disseminated lung diseases]

Lobule of the lung is a principal anatomical structure of the respiratory zone in the lungs. Secondary lobule of the lung consists of about fifty primary lobules and is delineated by fibrous interlobular septa. Each lobule is delineated by interlobular septa and blood is supplied by small arterioles of pulmonary artery system. Its shape is conical and size ranges from 10 to 22 mm. The author used algorithm of high resolution in HR CT to present normal distal generations of respiratory area of the lungs and the same in 32 patients with disseminated lesions to the lungs. It is known, that lobule of the lung may be involved in very important pathologies. The author shown that significant architectural rearrangement takes place in pulmonary lobules and adjacent areas in the course of disseminated pulmonary diseases. The process include thickening of interlobular septa, consolidation of lobular area, changes in the shape of lobuli, and appearance of small cysts. The use of HR CT enables imaging in such pathologies which normally are inaccessible to conventional radiologic examinations.     

Ultra-low field magnetic resonance tomography in the diagnosis of diseases of the spine and spinal cord]

A total of 309 investigated cases was analyzed with the help of the Magnaview apparatus with field intensity of 0.04 T. The method included obtaining both T1- and T2-suspended tomograms in the sagittal and, if necessary, transverse planes. MRT was shown to be an effective method of diagnosis and differential diagnosis of the compression syndrome of osteochondrosis, the effects of a "spinal" trauma, extra- and intramedullary tumors, metastatic vertebral involvement, postoperative changes, and syringomyelia.     

Effect of a double intervertebral cage on the mechanical behavior of the lumbar spine]

A three-dimensional nonlinear finite element model of the lumbar spine was developed. Paired threaded cages and a monosegmental internal spinal fixation device were integrated into the computer model. The model was loaded with such forces as apply during standing, as well as with pure moments in the three main anatomical planes, plus an additional preload. The latter was generated by shortening the distance between the pedicle screws on the longitudinal rod of the fixator. With the exception of torsional loading, an implant appreciably reduces the mobility in the segment concerned. At the loads studied, cages had only a minor impact on the movements and stresses in the adjacent regions, but a strong influence on the stresses in the endplates in contact with them. A preload increases these stresses dramatically. Contact conditions between vertebral body and cages also have a marked effect on the stress distribution in the corresponding vertebral endplate, especially in the case of extension loading. Owing to the preload, maximum stresses were higher for the rigid bond than when contact elements were used.     

Three-dimensional static modeling of the lumbar spine

This paper presents three-dimensional static modeling of the human lumbar spine to be used in the formation of anatomically-correct movement patterns for a fully cable-actuated robotic lumbar spine which can mimic in vivo human lumbar spine movements to provide better hands-on training for medical students. The mathematical model incorporates five lumbar vertebrae between the first lumbar vertebra and the sacrum, with dimensions of an average adult human spine. The vertebrae are connected to each other by elastic elements, torsional springs and a spherical joint located at the inferoposterior corner in the mid-sagittal plane of the vertebral body. Elastic elements represent the ligaments that surround the facet joints and the torsional springs represent the collective effect of intervertebral disc which plays a major role in balancing torsional load during upper body motion and the remaining ligaments that support the spinal column. The elastic elements and torsional springs are considered to be nonlinear. The nonlinear stiffness constants for six motion types were solved using a multiobjective optimization technique. The quantitative comparison between the angles of rotations predicted by the proposed model and in the experimental data confirmed that the model yields angles of rotation close to the experimental data. The main contribution is that the new model can be used for all motions while the experimental data was only obtained at discrete measurement points.     

Effect of lumbar fasciae on the stability of the lower lumbar spine

The biomechanical effect of tensioning the lumbar fasciae (LF) on the stability of the spine during sagittal plane motion was analysed using a validated finite element model of the normal lumbosacral spine (L4-S1). To apply the tension in the LF along the direction of the fibres, a local coordinate was allocated using dummy rigid beam elements that originated from the spinous process. Up to 10 Nm of flexion and 7.5 Nm of extension moment was applied with and without 20 N of lateral tension in the LF. A follower load of 400 N was additionally applied along the curvature of the spine. To identify how the magnitude of LF tension related to the stability of the spine, the tensioning on the fasciae was increased up to 40 N with an interval of 10 N under 7.5 Nm of flexion/extension moment. A fascial tension of 20 N produced a 59% decrease in angular motion at 2.5 Nm of flexion moment while there was a 12.3% decrease at 10 Nm in the L5-S1 segment. Its decrement was 53 and 9.6% at 2.5 Nm and 10 Nm, respectively, in the L4-L5 segment. Anterior translation was reduced by 12.1 and 39.0% at the L4-L5 and L5-S1 segments under 10 Nm of flexion moment, respectively. The flexion stiffness shows an almost linear increment with the increase in fascial tension. The results of this study showed that the effect of the LF on the stability of the spine is significant.