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At least 613 records · Page 34Linked to original sources

PubMed1976

[Determination of skull volume (author's transl)].

Various means for indirect skull volume determination were investigated. For this purpose--the procedure of direct measurement of skull volume was improved first, using a latex method. The examinations were carried out on 20 macerated skulls, which were x-rayed in the usual manner and stereoscopically also. Various distances and planes were then determined from the radiographs and varied calculations carried out. From these calculations it appears that skull volume can be simply determined most accurately from the product of transverse diameter (greatest width) and the area of median plane.

Adult↗

PubMedDate not supplied

[Scanning stereographic surface measurement in idiopathic scoliosis after VDS (ventral derotation spondylodesis)].

INTRODUCTION: So far only radiometric and clinical methods have been available for the evaluation of results after anterior scoliosis surgery. Rasterstereography has proved to be a reliable method for three-dimensional surface measurement of conservatively treated idiopathic scoliosis patients. Therefore, patients treated operatively with anterior instrumentation were examined using rasterstereography to determine the three-dimensional correction of the spinal deformity. The aim was to measure back shape deformity, in particular derotation, and thus cosmetic improvements. METHODS: 31 patients with idiopathic thoracic, thoracolumbar and lumbar scoliosis (Cobb angle 57.2 degrees) were examined with raster stereography preoperatively, postoperatively and after follow-up (25.2 months) in a standardized standing posture. Standing radiographs were compared with raster stereography. RESULTS: The mean Cobb angle was reduced from 57.2 degrees to 17.2 degrees, the rasterstereographic maximal surface rotation from 16.5 degrees to 10.8 degrees, and the vertebral rotation according to Perdriolle from 29.2 degrees to 16.7 degrees. During follow-up the Cobb angle increased to 20.8 degrees, and surface rotation to 11.3 degrees. Vertebral rotation remained constant. Lordosis and kyphosis angles changed only slightly. CONCLUSION: Rasterstereography is a suitable tool for analyzing the three-dimensional correction of spinal deformities after anterior scoliosis surgery. In particular, the cosmetic improvement is clearly demonstrated. The measurement of surface rotation allows objective quantification of the obtained derotation.

Adolescent↗

PubMed2002

Magnifying endoscopy, stereoscopic microscopy, and the microvascular architecture of superficial esophageal carcinoma.

BACKGROUND AND STUDY AIMS: In this study we clarify the microvascular architecture of superficial esophageal carcinoma as observed by ultra-high magnification endoscopy and stereoscopic microscopy with Microfil injection. PATIENTS AND METHODS: We observed two surgically resected specimens of superficial esophageal cancer under stereoscopic microscopy with Microfil injection. In addition, in the histological investigation, we measured the caliber of the vessels at the surface of the tumor. We carried out ultra-high magnification before treatment in 82 patients with superficial esophageal neoplasms. We classified the depth of tumor penetration of superficial esophageal carcinoma into four categories: m1 to m3 (mucosal cancer) and sm (submucosal cancer). RESULTS: By observing the normal esophageal mucosa under a stereoscopic microscope and an ultra-high magnification endoscope, we were able to visualize the intrapapillary capillary loops (IPCL). In cancer lesions, we observed characteristic changes in the superficial microvascular architecture according to the depth of tumor invasion. In m1 invasion, there was dilatation of the IPCL; in m2 invasion, there was dilatation and elongation of the IPCL; in m3, there was a mixed appearance of the IPCL and tumor vessels; and in sm invasion, complete replacement by tumor vessels. On the basis of the above criteria, ultra-high magnification endoscopic observation before treatment showed a rate of agreement between histological depth of invasion and magnified appearance of 60/72 cases (83.3 %) for which satisfactory pictures were obtained. The histological investigation showed the caliber of the IPCL of the m1 cancer lesions (12.9 +/- 3.9 microm) to be significantly greater than that of the normal esophageal mucosa (6.9 +/- 1.5 microm) (P < 0.0001). CONCLUSIONS: Observation of the microvascular architecture of superficial esophageal carcinoma is useful in the diagnosis of the depth of invasion.

Carcinoma↗

PubMed2005

Aortic stentgraft movement detection using digital roentgen stereophotogrammetric analysis on plane film radiographs -- initial results of a phantom study.

PURPOSE: To evaluate the feasibility of aortic stentgraft micromovement detection using digital roentgen stereophotogrammetric analysis on plane film radiographs. MATERIAL AND METHODS: An aortic stentgraft used for demonstration purposes was marked with 10 tantalum markers of 0.8 mm in diameter. The stentgraft was placed on a Plexiglas phantom with 5 tantalum markers of 1 mm in diameter simulating a fixed segment needed for mathematical analysis. In a subsequent step, the stentgraft was placed onto an orthopaedic spine model to simulate in vivo conditions.in a next step. Two radiographs taken simultaneously from different angles were used for simulating different stentgraft movement, e. g. translation, angulation, aortic pulsation and migration in the spine model. Movement of the stentgraft markers was analysed using a commercially available digital RSA setup (UmRSA(R) 4.1, RSA Biomedical, Umea, Sweden). RESULTS: Our study shows the feasibility of measuring aortic stentgraft movement and changes in stentgraft shape in the submillimeter range using digital roentgen stereophotogrammetric analysis. Translation along the 3 cardinal axes, change in stentgraft shape, simulation of aortic pulsation and simulation of in vivo conditions could be described precisely. CONCLUSION: Aortic stentgraft movement detection using digital roentgen stereophotogrammetric analysis on plane film radiographs is a very promising, precise method.

Aorta↗

PubMedDate not supplied

[Asymmetry of posture and truncal musculature following unilateral arm amputation--a clinical, electromyographic, posture analytical and photogrammetric study].

Unilateral upper limb amputation causes changes in statics of the spine. As a result asymmetrical posture of the spine, muscular asymmetries follow. In this study a population of upper limb amputees (above and below elbow amputees) is examined by clinical, electromyographical analysis and gait analysis. Upper limb amputations cause in correlation to weight loss a shift of the trunk to the side of the amputation, a scoliosis with a bowing to the side of the amputation, an elevation of the shoulder on the amputation side and a torsion of the trunk. Muscular asymmetries result from loss of function (muscles of the arm, M. latissimus, M. trapezius) and by shifting of the center of gravity. In order to get the center of gravity over the legs, the amputee compensates the loss of weight by shifting the upper trunk to the side of the amputation. As a result the shift of the segmental center of gravity at the lumber height to the side of the normal arm with muscular asymmetry in the erector trunci lumbalis results. As well we saw an overactivity of musculus glutaeus medius and resulting stress of the amputation sided hip joint. There was a remarkable difference between above and below elbow amputees caused by differences in weight loss. Muscular and static asymmetries in amputees who lost their arm only a short period before could be reduced by compensating the weight loss. Results for technical orthopaedic fitting and stress on gymnastic procedures to compensate these statistical problems are discussed.

Adult↗

PubMedDate not supplied

[Augmentation of VDS (ventral derotation spondylodesis) using double rod instrumentation: surgical method and early results].

INTRODUCTION AND AIM OF THE STUDY: The advantages of the VDS according to Zielke with excellent three dimensional correction and shorter fusion levels in comparison to posterior instrumentation techniques are well known. A disadvantage is the postoperatively necessary long immobilisation in a body cast due to lack of primary stability. Aim of the presented double-rod-VDS is to optimize the system by augmentation and allow a postoperative plaster cast- and brace-free treatment. METHOD AND MATERIAL: Following thoracolumbar phrenotomy and ligation of the segmental vessels Kaneda-clamps are inserted. First VDS-screws are implanted into the posterior holes of these clamps. Using a M-4 compression rod, correction is obtained by centripetal compressive forces to the nuts. Next VDS-screws for the M-5 treated rod are inserted into the anterior holes of the Kaneda clamps. The rod is implanted in a slightly compressive manner and augments the system. Within a prospective study 12 patients with idiopathic and neuromuscular scoliosis underwent this surgical procedure. Three patients with thoracolumbar scoliosis have been followed for 12 months postoperatively and are presented as case reports. All patients were treated brace-free postoperatively, only using a semi-elastic vest for 4 months. RESULTS: Remarkable intra- and postoperative complications have not been noted. Curve correction ranged from 75 to 86%. Implant related complications and loss of correction have not been noted so far. The sagittal plane was within physiological limits postoperatively. Scanning stereography demonstrated excellent three dimensional correction. CONCLUSION: The results of the Double-rod-VDS allow the statement, that the advantages of the VDS according to Zielke are optimized by augmentation of the system with the possibility of plaster cast and brace-free postoperative treatment. Larger operation numbers and a longer follow-up period are needed for further assessment.

Adolescent↗

PubMedDate not supplied

[Mobility of the sacroiliac joint in vitro].

A photogrammetric method was used to measure the range of motion of the iliosacral joint in a two-dimensional in-vitro model. The results were compared with values reported in the literature. The influence of morphological and histopathological parameters was simultaneously studied on the same objects. This method which does not use radiation or metal implants leads to comparable values. Three-dimensional in-vivo studies using similar photogrammetric methods can achieve the required accuracy in a less invasive way.

Adult↗

PubMed1991

Importance of morphological findings in the progress and treatment of chest wall deformities with special reference to the value of computed tomography, echocardiography and stereophotogrammetry.

Patients with chest wall deformities have many particular anatomical, physiological, genetic, biomechanical and psychological characteristics. It is generally recognized that surgical correction of funnel chest and pigeon breast may be done for psychosocial reasons alone. Morphological and dynamic investigations are done to identify the function of the deformed chest wall and to permit objective assessment of the cosmetic and functional outcomes of the operation. There is no universally agreed standard for the diagnosis of funnel chest and pigeon breast. Non-invasive investigations, such as computed tomography (CT), echocardiography (ECG) and stereophotogrammetry (SP), improve the quality of the diagnostic assessment, including evaluation of its functional aspects, without directly influencing the decision to operate, which is still made mainly on subjective grounds. The value of these techniques in the diagnosis of chest wall deformities is assessed and the results of our personal experience are presented.

Adolescent↗

PubMed1986

Rasterstereography in the measurement and postoperative follow-up of anterior chest wall deformities.

Rasterstereography is a contact-free photogrammetric method for the measurement of body surfaces. As such it is particularly suited for the objective documentation of anterior chest wall deformities and the results of surgery. An example of its application and first results are presented. The possibilities of a thorough data analysis with regard to diagnosis and therapy control are outlined.

Adolescent↗

PubMedDate not supplied

[3-dimensional surface measurement of spinal deformities with video rasterstereography].

QUESTION: Video rasterstereography is a method for back surface measurement comprising automatic back surface reconstruction and shape analysis. Aim of this prospective study was to determine the accuracy of this method in comparison to the conventional frontal and lateral standing radiographs. METHOD: 95 patients with idiopathic scoliosis or scoliotic postural abnormalities and 18 patients with thoracic hyperkyphosis and Scheuermann's disease were investigated. The Cobb angles, the sagittal profile and apical vertebral rotation as well as pelvic obliquity and trunk decompensation were measured. The analysis was carried out by two independent observers. RESULTS: The root mean square (r.m.s.) deviation of the Cobb angle in the cases of idiopathic scoliosis ranged between 7 degrees and 8 degrees. In video rasterstereography there were no false negative results and two false positive results concerning differentiation between structural scoliosis and scoliotic postural abnormality. The r.m.s. deviation of apical vertebral rotation averaged 7.9 degrees and for pelvic obliquity respectively trunk imbalance 0.65 cm respectively 1.07 cm. The thoracic hyperkyphosis in Scheuermann's disease showed a r.m.s. deviation of 5.6 degrees. CONCLUSIONS: Video rasterstereography is a reliable method in the three-dimensional evaluation of spinal deformities and constitutes a valuable additional tool to the clinical examination and can reduce the number of radiographs.

Adolescent↗

PubMedDate not supplied

[Spatial orientation of the facies patellaris femoris].

The present article reports on the geometrical conditions of the physiological movement of the patella. The geometrical shape of 18 femoral condyles and patella sliding areas was investigated in order to describe basic data for the design of endoprostheses. Surface and direction of the facies patellaris femoris were determined by means of radiographic, mechanical and optical measurements. The curvature of the deepest patella sliding groove proves a constant correlation with the dorsal condylar curvature. In the frontal plane the lowest points of the sliding area run with a dispersion of +/- 4 degrees to the vertical line related to the transverse tangent on the dorsal condylar surface. Considering deviations of leg alignment the measures come close to an angle of about 0 degrees. So the direction of the patella sliding groove differs from the normal valgus position of the distal femur. Therefore in artificial knee replacement a lateral tilt of the patella sliding groove should not be propagated as 'physiological'.

Biomechanical Phenomena↗

PubMedDate not supplied

[Biomechanics of the metatarsophalangeal joints].

Koehler-Freiberg's disease is found to most commonly manifest itself in the metatarsal head of the second ray. Occasionally it is observed to occur in the metatarsal head of the third and less commonly it is seen to appear in the other rays of the foot. An investigation into probable causes of the disorder calls for consideration of the biomechanical conditions in the region of the metatarsophalangeal joints. A review of the literature pertaining to this matter has failed to reveal any detailed information in this respect and therefore a series of experiments have been conducted involving determination of a) the ground force under the metatarsophalangeal joints and under the toes in normal barefoot walking b) the direction of the flexor tendons and such others that cross the joint and that might play an important role in exerting force between the toes and the ground, c) the geometry of the articulating surfaces and d) the forces that act between the metatarsal head and the corresponding phalangeal joint surface. It is shown that the specific loading of the MP-II joint (due to forces acting across the joint) could amount to nearly twice that to which MP-I is subjected to. This might explain the more frequent occurrence of osteonecrosis of the second metatarsal head as compared to that observed within the head of the first. Furthermore, the direction of the joint resultant force in the MP-II joint is seen to be more dorsally inclined than that in MP-I, which agrees well with clinical findings regarding the site of localized lesions. Lastly, a hypothesis which still requires closer investigation is presented to explain the development of the bone lesions that are known to occur just below the subchondral cortex.

Biomechanical Phenomena↗

PubMedDate not supplied

[Value or lack of value of the Landwehr so-called balance scale].

A screening investigation was carried out at our department to study the equilibrium balance according to Landwehr, which is used for X-ray photographs as well as for Moiré or grid photometric analyses of the spine while standing in the upright position. If has been demonstrated that the balance could be "deceived" without difficulty by persons who are aware of its mechanism of action and who intend to do so, which means that its application does not necessarily yield "faultless reproducible radiographs", as Bernau has insisted. If the experiment is carried out with persons standing on the balance without prejudice, there is a high probability of better reproduction of the posture than without using the balance, though particular cases may assume an unnatural posture. A screening investigation using the equilibrium balance with 3000 pupils yielded 12% less false positive results. As a consequence of this investigation, we believe that after weighing the advantages and disadvantages, we can recommend the balance for both X-ray photographs and Moiré as well as grid analyses of the dorsum. In addition, appropriate use of the equilibrium balance provides better comparison of different results of treatment.

Humans↗

PubMedDate not supplied

[Reproducibility of surface measurements of the back using the opTRImetric method].

The early detection of scoliosis as well as the supervision of its progress without or with a minimal number of X-rays, is the aim of surface measurements by the opTRImetric method. The device, the method and the measured variables are described. The main aim of the work was the determination of the reproducibility of the measured variables. The variation of the measured variables caused by the stance and measurement method are given. It appears that the use of a balance for equal footloading results in a posture different from the "normal" one, and that the reproducibility of this posture seems even less than of the posture adopted when equiloading of the legs is subjectively attempted.

Adolescent↗

PubMedDate not supplied

[Objective determination of the shape of the anterior chest wall using moiré topography. Method and development of dimension-free indices for the evaluation of funnel chest].

Stereophotogrammetric measurement of body surface results in data, which are dependent on shape, posture and positioning of the patient. In order to establish a valid description and characterization of funnel chest measured by stereophotogrammetric methods, index numbers must be defined, which are independent of posture und positioning of the patient. This procedure is exemplified in the analysis of moiré topograms from 29 patients with funnel chest and 21 normal persons. The sagittal cross section is characterized by the index TI I, which in essential is the sum of absolute values of angles in a polygon along the section (cf. fig. 7). The funnel in the coronal cross section is characterized by the index TI II, which gives the quotient (in %) of the mean funnel width and funnel depth (cf. fig. 8). Application of the index numbers shows a good differentiation of TI I, independent of sex, whereas TI II might be most useful in follow up measurements.

Adolescent↗

PubMed1982

[The measurement of the kyphotic angle by contact free registration of back-shape (author's transl)].

Contour line patterns, as they are produced by Moiré Topography are dependent of position, posture and body-shape of the patient. For all medical applications data are needed, which are only dependent of shape and posture and which therefore have to be independent of positioning. Angles between tangents to the body surface are independent of positioning. The measurement of angles in general and the measurement of the inflectional tangent angle in particular is discussed for Moiré topograms. The angle against the grating plane of the Moiré apparatus can be found by calipering the fringe distance in the topogram and comparison with a tangent curve, photographically registered with each topogram (Fig 4). The difference of the two extreme angles along the profile (Fig. 5 a) equals the kyphotic angle. The inflectional points along the profile, where the angles are to be measured, are recognizable by the minimal vertical fringe distance in the topogram (Fig. 6). Although the kyphotic angle refers to the body surface, its definition equals in geometrical terms to that of the Cobb-angle (Fig. 7). A comparison between these two angles in 61 patients (Fig. 8) yields a correlation coefficient of 0.87.

Anthropometry↗

PubMed1980

[Stereochronoscopy].

If fundus photographs are taken at different times under strictly observed conditions of centering, temporal changes of the disk surface can rapidly be detected by stereoscopic methods. In glaucoma (early or late stages) such changes are found earlier than by routine perimetry. Hence, the onset of glaucoma can more easily be distinguished from real ocular hypertension, and success of therapy can be judged more accurately than by visual field determinations.

Glaucoma↗

PubMed2001

Acquisition of 3-dimensional shapes from images.

Advances in computer vision have started to infiltrate the specialty of orthodontics. During the past few years, a number of new products have appeared that are capable of extracting the 3-dimensional (3-D) structure of an object just by "looking." Examples include laser scanners for creating 3-D models of the face, and hand-held scanners for creating virtual models of the teeth. Such noninvasive methods will surely evolve rapidly and be applied to a multitude of diagnostic and therapeutic modalities, changing the way we think and practice. This article introduces the basic principles behind such technology so that we can better appreciate its advantages, limitations and possibilities. From the large number of methods for acquiring 3-D shapes from images, 4 were selected and are described below. For more comprehensive coverage, see the book by Klette et al (1).

Humans↗