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Biomedical subjects

M Biggemann

Publications and source records attributed to M Biggemann.

13 recordsLinked to original sources
PubMed2002

Sagittal plane segmental motion of the cervical spine. A new precision measurement protocol and normal motion data of healthy adults.

OBJECTIVE: (1) Precise documentation of sagittal plane segmental rotational and posteroanterior translational motion of segments C0/C1-C6/C7 of the human cervical spine from lateral radiographic views. (2) Compilation of a database describing normal motion. (3) Comparison of individual motion patterns with the normal database. DESIGN: Descriptive study based on computer-aided measurements from lateral radiographic views taken in flexion and extension. BACKGROUND: Previous studies concentrated on segmental rotational motion of the cervical spine. Normal data for translational motion were not available. Description of cervical spine motion patterns thus remained incomplete. METHODS: Based on computer-aided measurements from lateral radiographic views taken in flexion and extension, a new protocol determines rotational and translational motion for all segments (C0/C1-C6/C7) imaged on the radiographic views. Measured results are corrected for radiographic magnification and variation in stature; they are virtually uninfluenced by radiographic distortion and patient alignment errors. A database describing normal motion was compiled from 137 sets of lateral views of healthy adults taken in active flexion and extension. A specimen study as well as inter- and intra-observer studies quantify measurement errors. RESULTS: The error study demonstrated the error (SD) of a rotational motion measurement to amount to slightly less than 2 degrees. The error (SD) of a translational motion measurement amounts to less than 5% of vertebral depth; for a vertebra of 15 mm depth this corresponds to 0.7 mm. A normal database for rotational and translational motion was compiled. There was a linear relation between rotational and translational motion. This finding agrees qualitatively with results from previous studies; quantitative comparisons are not possible due to divergent definitions for translational motion. The relation between rotation and translation can be employed in individual cases to predict translational motion, in dependence on the rotation actually performed. A comparison of the rotational motion with the normal database and the difference between predicted and actual translational motion allow segmental hypo-, normal or hypermobility to be quantified. CONCLUSIONS: The new protocol measures segmental motion with high precision and corrects for radiographic distortion, variation in stature and alignment errors of patients. Thus, archive studies using existing radiographs are feasible. RELEVANCE: Flexion-extension radiographs of the cervical spine are performed to explore potential damage to the bony or ligamentous structure resulting in abnormal, segmental motion patterns. Determining rotational motion gives only an incomplete picture. The new protocol allows for precise quantification of translational motion and classification of segments as hypo- or hypermobile by comparison with normal motion data.

Adolescent↗
PubMed2002

Vertebral height, disc height, posteroanterior displacement and dens-atlas gap in the cervical spine: precision measurement protocol and normal data.

OBJECTIVE: (1) Precise measurement of vertebral height, disc height, posteroanterior displacement and dens-atlas gap from lateral radiographic views of the cervical spine. (2) Compilation of a normative database for these parameters, specifying dependence on gender and age. DESIGN: Descriptive study, based on measurements from lateral radiographic views of the cervical spine of healthy subjects. BACKGROUND: Normal data of vertebral height, disc height, posteroanterior displacement and size of the dens-atlas gap as well as their biological range of variation and potential dependence on gender and age are not available. METHODS: Based on computer-aided measurements from lateral radiographic views of the cervical spine, a new protocol determines these parameters. RESULTS: are compensated for radiographic magnification, variation in stature and the individually adopted posture of the cervical spine; they are virtually uninfluenced by radiographic distortion and patient alignment errors. A specimen study as well as inter- and intra-observer studies quantify measurement errors.Results. Employing the new protocol, vertebral height C3-C7 and disc height C2/C3-C6/C7 are measured with relative errors of 3.9% and 5.7% respectively. Posteroanterior displacement C1/C2 to C6/C7 is measured with an error of 2.8% of mean vertebral depth and the dens-atlas gap is measured with an error of <1.8% of the depth of C2. A normal database for the dimensions of cervical vertebrae and discs as well as of the sagittal plane alignment of the vertebrae within the cervical spine is compiled from 135 lateral views of healthy adults. CONCLUSIONS: Vertebral height, disc height, posteroanterior displacement and size of the dens-atlas gap are measured with high precision. Normal data are presented for the first time. RELEVANCE: The new protocol in conjunction with the normal database enables future studies detecting or monitoring morphological effects of, for example, trauma, long-term high mechanical loading, disc degeneration, rheumatoid arthritis, fusion or other surgical interventions.

Adult↗
PubMed2002

[Sagittal plane rotational and translational motion of lumbar segments with decreascd intervertebral disc height].

PURPOSE: Employing a precise measurement protocol, it was investigated whether decreased height of lumbar discs is related to an increase of sagittal plane segmental motion or to a displacement of the cranial vertebra into a retrolisthesis position. METHODS: The height of the intervertebral discs, the dorsoventral displacement of the cranial vertebra and the range of sagittal plane rotational and transitional motion were measured for all segments of the lumbar spine from flexion-extension views of 30 patients. In each patient, at least one lumbar disc exhibited a significant height decrease. The measurement was performed using a new protocol compensating for distortion in central projection, off-centre position, axial rotation and lateral tilt of the spine. Measured data on retrolisthesis position, rotational and translational motion were compared with previously compiled age- and gender-appropriate normal data. RESULTS: In the cohort investigated there was no statistically significant relation between a decrease of disc height and segmental hypermobility with respect to sagittal plane rotation or translation. There was no relation between a decrease of disc height and a displacement of the adjacent cranial vertebra into a retrolisthesis position. CONCLUSIONS: The results challenge the often postulated relation between low disc height and segmental hypermobility ("instability") and retrolisthesis position of the cranially adjacent vertebra.

Adolescent↗
PubMed1997

[The physiological pattern of lumbar intervertebral disk height].

UNLABELLED: Purpose of this study is to present a new method of quantifying objectively the height of all discs in lateral radiographs of the lumbar spine and of analysing the normal craniocaudal sequence pattern of lumbar disc heights. METHODS: The new parameter is the ventrally measured disc height corrected for the dependence on the angle of lordosis by normalisation to mean angles observed in the erect posture of healthy persons. To eliminate radiographic magnification, the corrected ventral height is related to the mean depth of the cranially adjoining vertebra. In this manner lumbar disc heights were objectively measured in young, mature and healthy persons (146 males and 65 females). The craniocaudal sequence pattern was analysed by mean values from all persons and by height differences of adjoining discs in each individual lumbar spine. RESULTS: Mean normative values demonstrated an increase in disc height between L1/L2 and L4/L5 and a constant or decreasing disc height between L4/L5 and L5/S1. However, this "physiological sequence of disc height in the statistical mean" was observed in only 36% of normal males and 55% of normal females. CONCLUSION: The radiological pattern of the "physiological sequence of lumbar disc height" leads to a relevant portion of false positive pathological results especially at L4/L5. An increase of disc height from L4/L5 to L5/S1 may be normal. The recognition of decreased disc height should be based on an abrupt change in the heights of adjoining discs and not on a deviation from a craniocaudal sequence pattern.

Adolescent↗
PubMed1996

Precision measurement of segmental motion from flexion-extension radiographs of the lumbar spine.

OBJECTIVE: To measure sagittal plane motion of lumbar vertebrae from lateral radiographic views. Previously identified factors of imprecision such as distortion in central projection, off-centre position, axial rotation, and lateral tilt of the spine were compensated. STUDY DESIGN: This study presents a new protocol to measure sagittal plane rotational and translational motion from lateral flexion-extension radiographs of the lumbar spine. BACKGROUND: Conventional methods to determine sagittal plane rotation and translation are prone to error from the distortional effects of the divergence of the radiographic beam and the measurement error inherent in constructing tangents to the contours of the vertebral body. High precision is attained by roentgen-stereophotogrammetric methods, but because of their invasive nature they can be applied only in exceptional cases. Agreement has been reached only in that measurement of sagittal plane motion from lumbar spine flexion-extension radiographs is inaccurate. Normal patterns of sagittal plane motion and the definition of what is an abnormal flexion-extension radiograph have not been settled. METHOD: Starting from an analysis of vertebral contours in the lateral view, geometric measures are identified which are virtually independent of distortion, axial rotation or lateral tilt. Applying a new protocol based on those geometric measures, the pattern of translational and rotational motion was determined from flexion-extension radiographs of 61 symptom-free, adult subjects. Measurement errors were quantified in a specimen experiment; a reproducibility study quantified inter- and intraobserver errors. RESULTS: Magnitude and sign of 'translation per degree of rotation' determined from a cohort of 61 adult subjects were very uniform for all levels of the lumbar spine. An auxiliary study evaluating a cohort of 10 healthy subjects where flexion-extension radiographs had been taken standing and side-lying showed no dependence of the rotation/translation pattern on posture. The error study demonstrated errors in angle ranging between 0.7 and 1.6 degrees and errors in displacement ranging between 1.2% and 2.4% of vertebral depth (the largest errors occurring at the L(5)/S(1) segment). Intra- and interobserver tests showed no or only negligibly small bias and an SD virtually equal to the measurement error multiplied by radical2. The relation of displacement to angle observed in the normal cohort can be used in individual cases to predict translational motion depending on the rotation actually performed. A comparison of the predicted translation (determined from normal controls) and the value actually measured allows translational hypo-, normal, or hypermobility to be quantified. Examples illustrate application of the new method in cases of normal, hypo-, and hypermobility and in the case of an instrumented spine. CONCLUSIONS: The results of this study show that precision of the measurement of rotational and translational motion can be considerably enhanced by making allowance for radiographic distortional effects and by minimizing subjective influence in the measurement procedure.

Journal Article↗
PubMed1991

[Aortobronchopulmonary fistula following a pulmonary contained aortic rupture in patients with a thoracic aortic aneurysm and severe aortic sclerosis].

Rupture of the thoracic aorta is usually widespread and fatal. Rupture limited by the lung and aorto-bronchopulmonary fistula are rare. We report two patients with a contained perforation of the thoracic aorta, who presented with haemoptysis. Chest radiographs demonstrated an aortic aneurysm and pulmonary haemorrhage in the first, while in the other perforation of an atherosclerotic aorta with a pulmonary haematoma was misinterpreted as bronchial carcinoma. In both cases contrast enhanced CT clearly demonstrated the abnormality in the aorta and the pulmonary haemorrhage. Since aortography often fails to demonstrate a perforation, CT or MRI should be performed early in patients with suspected rupture of the thoracic aorta.

Aged↗
PubMed1990

[Mediastinal and bronchovascular amyloidosis. An unusual x-ray morphologic finding].

The clinical and radiographic aspects of an unusual case of mediastinal and bronchovascular amyloidosis are presented. Besides hilar and mediastinal lymphadenopathy, extensive amyloid deposition in the peribronchial and perivascular connective tissue sheaths can be observed. Plain film radiographs and CT demonstrate an uncommon pattern of increased bronchovascular markings, which is discussed. Because of peribronchial amyloid deposits, bronchoscopy is of no help in demonstrating this special type of tracheobronchial amyloidosis.

Amyloidosis↗
PubMed1989

[Experimental research on the quantitative computed tomographic prediction of the compressive strength of the thoracolumbar vertebrae].

Testing 98 motion segments we investigated the possibility of a prediction of the compressive strength of thoracolumbar vertebrae by QCT. The ultimate compressive strength can be predicted from the density of the trabecular bone and from the size of the endplates--both determined by QCT--with an error of 1 kN. The increase of compressive strength in craniocaudal direction is calculated at approximately 0.3 kN per anatomical level. This variation is due to the increase of the endplate areas.

Adult↗
PubMed1989

Prediction of the compressive strength of human lumbar vertebrae.

The compressive strength of 98 specimens of motion segments of human thoracolumbar spines was measured. In addition, the density of the trabecular bone in the midplane of the vertebrae was assessed by quantitative computed tomography (QCT); the size of the vertebral endplates was measured by CT as well. The results show that the compressive strength of thoracolumbar vertebrae can be predicted from the product of density and end-plate area, with an error of estimate of 1 kN. The data of the experiment allow for an in vivo prediction of the strength of vertebrae to quantify the risk of fracture in physically very demanding tasks, to support expert opinion in trauma cases, or to assist in therapeutic decisions in cases of severe osteoporosis.

Humans↗
PubMed1988

Prediction of the compressive strength of vertebral bodies of the lumbar spine by quantitative computed tomography.

The ultimate compressive strength of 36 thoracolumbar vertebrae was determined experimentally. In addition, the trabecular bone mineral content was measured by single energy quantitative computed tomography. The areas of fractured endplates were also determined by computed tomography. The results show that a linear relationship exists between the compressive strength and the product of bone density and endplate area. These data allow an in vivo prediction of vertebral body strength using a noninvasive method with a standard error of estimate amounting to less than 0.95 kN.

Adult↗
PubMedDate not supplied

Risk of vertebral insufficiency fractures in relation to compressive strength predicted by quantitative computed tomography.

Vertebral insufficiency fractures may result from excessive loading of normal and routine loading of osteoporotic spines. Fracture occurs when the mechanical load exceeds the vertebral compressive strength, i.e., the maximum load a vertebra can tolerate. Vertebral compressive strength is determined by trabecular bone density and the size of endplate area. Both parameters can be measured non-invasively by quantitative computed tomography (QCT). In 75 patients compressive strength (i.e., trabecular bone density and endplate area) of the vertebra L3 was determined using QCT. In addition, conventional radiographs of the spines were analysed for the prevalence of insufficiency fractures in each case. By relating fracture prevalence to strength, three fracture risk groups were found: a high-risk group with strength values of L3 less than 3 kN (kilo Newton) and a fracture risk of 100%, an intermediate group with strength values from 3 to 5 kN and a steeply increasing risk with decreasing strength, and a low-risk group with strength values greater than 5 kN and a fracture risk near 0%. Biomechanical measurements and model calculations indicate that spinal loads of 3 to 4 kN at L3/4 will be common in everyday activities. These data and the results described above suggest that spines with strength values of L3 less than 3 kN are at an extremely high risk of insufficiency fractures in daily life. Advantages of fracture risk assessment by strength determination over risk estimation based on clinically used trabecular bone density measurements are discussed.

Adult↗
PubMedDate not supplied

[Objective measurement of the height of lumbar intervertebral disks from lateral roentgen views of the spine].

OBJECTIVE: Published methods to quantify height of lumbar discs from lateral radiographic views of the lumbar spine yield inaccurate results due to distortion in central projection. Normal values of disc height have not been compiled. METHODS: Starting from an analysis of the imaging properties of vertebral bodies in a lateral view and following a logical evolution of Farfan's proposal, a new protocol for the measurement of disc height is given which is independent of distortion. A database of normal values of the height of lumbar discs from T12/L1 to L5/S1 was compiled from 892 lateral views of healthy male and female subjects in the age range between 16 and 57 years. RESULTS: Employing the new protocol, height of all discs on a lateral view can be measured. Variations in position (standing, side-lying) do not influence the result. Retrospective investigations are feasible. The precision of the disc height measurement amounts to 4.15%. Normal, age-appropriate values for the height of lumbar discs are given for the first time. In the individual case, disc height can be quantitatively evaluated by comparison with the normative database. CLINICAL RELEVANCE: The new protocol can be employed to quantitatively identify processes which effect a decrease of disc height. In the individual case, the new protocol and the comparison with the normal database can be employed to quantitatively assess overload injury to lumbar discs in compensation cases.

Adolescent↗