Changes in disc height and posteroanterior displacement after fusion in patients with idiopathic scoliosis: a 9-year follow-up study.

Introduction: In scoliosis patients treated with long segment spinal fusion, degenerative changes like retrolisthesis and disc space narrowing below fusion have been observed. However, there is disagreement concerning their incidence and dependency on the location of the lowest instrumented vertebra.

Materials And Methods: To evaluate temporal changes in disc height and posteroanterior displacement (indicating listhesis) below fusion, 40 patients with adolescent idiopathic scoliosis, mainly treated with Cotrel-Dubousset instrumentation, were retrospectively investigated in this longitudinal study with a follow-up of on average 9.

Mobility of lumbar segments instrumented with a ProDisc II prosthesis: a two-year follow-up study.

Study Design: Longitudinal prospective study on a sample of 41 consecutive disc prosthesis patients, covering a postoperative time period of at least 2 years.

Objectives: To document the rotational and translational range of segmental motion of patients instrumented with ProDisc II prostheses in the lumbar spine and to compare motion between instrumented and untreated adjacent segments with respect to a normative database. To discuss potential causes of the low range of rotational motion observed after instrumentation with a Prodisc II prosthesis.

Comparing precision of distortion-compensated and stereophotogrammetric Roentgen analysis when monitoring fusion in the cervical spine.

Two methods to measure sagittal plane segmental motion in the cervical spine are compared. Translational and rotational motion was measured in nine cervical motion segments of nine patients by distortion-compensated (DCRA) as well as by stereophotogrammetric Roentgen analysis (RSA). To compare measurement precision of the new DCRA protocol with the established RSA technique under realistic clinical conditions and to discuss advantages and disadvantages of both methods in clinical studies.

Congenital cervical block vertebrae are associated with caudally adjacent discs.

Background: Knowledge on the time course of changes in cervical disc height and cervical kinematics at motion segments adjacent to congenital block vertebrae is fragmentary. Compared with this, after surgical fusion of cervical spine segments some find increased degenerative processes in combination with hypermobility or instability while others were unable to confirm these changes. This cross sectional study was undertaken to investigate whether congenital block vertebrae are associated with an increased risk of disc degeneration and hypermobility at adjacent motion segments.

Increased sagittal plane segmental motion in the lower cervical spine in women with chronic whiplash-associated disorders, grades I-II: a case-control study using a new measurement protocol.

Study Design: Case-control study comparing sagittal plane segmental motion in women (n = 34) with chronic whiplash-associated disorders, Grades I-II, with women (n = 35) with chronic insidious onset neck pain and with a normal database of sagittal plane rotational and translational motion.

Objective: To reveal whether women with chronic whiplash-associated disorders, Grades I-II, demonstrate evidence of abnormal segmental motions in the cervical spine.

Summary Of Background Data: It is hypothesized that unphysiological spinal motion experienced during an automobile accident may result in a persistent disturbance of segmental motion.

Disc height and anteroposterior translation in fused and adjacent segments after lumbar spine fusion.

In a series of 46 patients the effects of spinal fusion upon intervertebral height and sagittal alignment in operated and non-operated segments were retrospectively evaluated on digitized radiographs. Data was compared with age- and gender-normalized standard values. The objective was to evaluate the influence of different types of spine fusions primarily upon adjacent segments, particularly in terms of degeneration and sagittal profile of the lumbar spine.

[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.

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.

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.

Height of lumbar discs measured from radiographs compared with degeneration and height classified from MR images.

The relation between height of lumbar discs (measured from lateral radiographic views) and disc degeneration (classified from MR images) deserves attention in view of the wide, often parallel or interchanged use of both methods. The time sequence of degenerative signs and decrease of disc height is controversial. To clarify the issue, this cross-sectional study documents the relation between disc degeneration and disc height in a selected cohort.

Do human lumbar discs reconstitute after chemonucleolysis? A 7-year follow-up study.

Study Design: A retrospective, longitudinal study of 51 patients, covering a mean follow-up period of 81 months.

Objective: To observe the long-term temporal course of the height of human lumbar discs after chemonucleolysis. To document whether human lumbar discs reconstitute, thus characterizing the healing potential of central disc tissue.

Assessment of sagittal plane segmental motion in the lumbar spine. A comparison between distortion-compensated and stereophotogrammetric roentgen analysis.

Study Design: Sagittal plane translatory and rotatory motion was measured in 15 lumbar motion segments of 8 patients by distortion-compensated and stereophotogrammetric Roentgen analysis.

Objective: To compare measurement precision of the new distortion-compensated Roentgen analysis protocol with that of the established Roentgen stereophotogrammetric technique under realistic clinical conditions.

Summary Of Background Data: Roentgen stereophotogrammetric analysis constitutes the most precise method available to assess segmental motion.

[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.

[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.

Precision measurement of disc height, vertebral height and sagittal plane displacement from lateral radiographic views of the lumbar spine.

OBJECTIVE.: To compile a database of disc height, vertebral height and sagittal plane displacement from lateral radiographic views of the lumbar spine, valid for male and female subjects in the age range 16-57 years. The protocols used to measure these parameters compensate for distortion in central projection, off-centre position, axial rotation and lateral tilt of the spine as well as for variation in radiographic magnification and stature.

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.

Quantification of overload injuries to thoracolumbar vertebrae and discs in persons exposed to heavy physical exertions or vibration at the work-place The shape of vertebrae and intervertebral discs - study of a young, healthy population and a middle-aged control group.

The ongoing search for causes (and strategies for prevention) of low back trouble in sub-groups of the population exposed to heavy physical exertions or whole body vibration requires reliable data on the prevalence of lower-spine overload damage. Because published reports on this topic are rare and mostly qualitative, the present study was initiated to assess, objectively and quantitatively, overload damage to vertebrae and intervertebral discs. Part I of the work has involved the establishment of a normative database of shape parameters from measurements of 683 (539 male, 144 female) lateral radiographic views of the thoracolumbar spine of young (17-30 years), healthy subjects.

An improved method of stature measurement for quantitative determination of spinal loading. Application to sitting postures and whole body vibration.

A refined procedure for measuring stature is described; this provides a reproducibility error of 0.4 mm. The procedure accommodates the natural diurnal change in stature and permits estimation of the net stature change caused by a change in spinal loading.

Deformation of the vertebral end-plate under axial loading of the spine.

When the published data on the radial disc bulge in relation to the axial compression of the motion segment are compared to a simple mechanical model, it follows that an axial inward bulge of the vertebral endplates should occur during compression. The model predicts that the disc height at its center should remain practically constant under compression. The axial endplate bulge has been measured in specimens of the human lumbar spine by stereoroentgen-photogrammetric methods.

Analysis of human back shape using surface curvatures.

A method for the evaluation of surface measurements of the human back is presented. A shape analysis is carried out in terms of surface curvature. This is calculated using differential geometry of surfaces.