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J Sevastik

Publications and source records attributed to J Sevastik.

16 recordsLinked to original sources
PubMed2003

A new concept for the etiopathogenesis of the thoracospinal deformity of idiopathic scoliosis: summary of an electronic focus group debate of the IBSE.

There is no generally accepted scientific theory for the etiology of idiopathic scoliosis, and treatment is pragmatic and unrelated to such knowledge. As part of its mission to widen understanding of scoliosis etiology, the International Federated Body on Scoliosis Etiology (IBSE) introduced the electronic focus group (EFG) as a means of increasing debate of extant knowledge on important topics. This has been designated as an on-line Delphi discussion, and has proven very successful. The text for this EFG was written by Professor Sevastik and drawn from the extensive research carried out by himself and his co-workers. The thoracospinal concept of etiopathogenesis applies only to girls with right thoracic adolescent idiopathic scoliosis (Rcx-T-AIS-F). According to this concept, increased longitudinal growth of the left periapical ribs triggers the thoracic curve simultaneously in the three cardinal planes. The concept does not deal with factors involved in curve progression. Sevastik advocates mini-invasive operations on the ribs as a treatment for early progressive thoracic curves. Areas of controversy include whether or not there is overgrowth of the left periapical ribs in Rcx-T-AIS-F, and the question of whether there should be a clinical trial of mini-invasive operations on the ribs.

Adolescent↗
PubMed1997

Rib-vertebral angle asymmetry in idiopathic, neuromuscular and experimentally induced scoliosis.

The concave and convex rib-vertebral angle (RVA) at levels T2-T12 was measured on AP radiographs of 19 patients with right convex idiopathic thoracic scoliosis and 10 patients with major thoracic right convex neuromuscular scoliosis. The difference between the angles on the concave and the convex sides, the RVAD, was calculated. The RVAs were also measured on radiographs from three animal groups in which spinal curves had been induced experimentally in a variety of ways. Group 1 comprised 16 rabbits that had been subjected to selective electrostimulation of the latissimus dorsi, the erector spinae and the intercostal muscles. Group 2 comprised four dead rabbits whose spines had been subjected to manual bending. Group 3 comprised eight rabbits that had undergone mechanical elongation of one rib. In both the idiopathic and the neuromuscular group, the convex RVA was smaller than the concave RVA between levels T2 and T8, with a maximal difference between T4 to T5. From T9 to T12 the concave RVA was smaller than the convex. The RVA in relation to the scoliotic segment, i.e. the apex level of the curve and the two neighbouring vertebrae above and below this level, showed similar results. With increasing Cobb angle the RVADs increased linearly with the greatest difference at the second vertebra above the apex. In the three experimental groups the pattern of the RVADs between T6 to T12 was basically similar to the findings of the clinical study. From the results of these clinical and experimental studies, it is concluded that the typical pattern of the RVAs on the concave and convex sides seems to be independent of the underlying cause of the spinal curvature. It is likely that the RVADs result from a passive mechanical adaptation of the ribs to the lateral curvature of the spine.

Adolescent↗
PubMed1996

The position of the aorta in relation to the vertebra in patients with idiopathic thoracic scoliosis.

One CT-scan at the central part of the vertebral body of the apical vertebra of 32 patients with right convex thoracic idiopathic scoliosis and one CT-scan of either T8 or T9 of 22 normal subjects are included in this study. The position of the aorta in relation to the apical vertebra of the scoliotic patients and the corresponding vertebra of the normal subjects was determined at the horizontal plane. The mean lateral translation of the aorta in relation to the mid axis of the vertebral body increased from 19.7 +/- 4.3 mm in the normal group to 26.4 +/- 4.1 mm in the scoliotic group (p = 0.0001). In the normal group the aorta was located 41.7 +/- 8.6 mm in front of a perpendicular line to the mid axis of the vertebral body and in the scoliotic group this distance was reduced to 30.0 +/- 9.0 mm making the position of the aorta more posterior in the scoliotic group (p = 0.0001). This was in accordance with a decreased mean kyphosis-lordosis index from 0.53 +/- 0.06 in the normal group to 0.46 +/- 0.07 in the scoliotic group (p = 0.01). The position of the aorta, also expressed as the angle formed between the aorta and the vertebral body, the "aorto-vertebral angle", was increased from 24.4 degrees +/- 6.9 degrees in the normal group to 41.4 degrees +/- 8.4 degrees the scoliotic patients, (p = 0.0001). The aorto-vertebral angle did not change significantly with increasing Cobb angle (p = 0.26) but was positively correlated to the vertebral rotation (p = 0.0001). An estimation of the length of the intercostal arteries revealed a significantly greater R (right)/L (left) index in the scoliotic patients 1.18 +/- 0.11 than in the normal subjects 1.08 +/- 0.06 (p = 0.0003). It is concluded that the rotation and the anterior displacement of the vertebral body in scoliosis result in a deviation of the aorta along the left (concave) side of the vertebral body to a more posterior position relative to the vertebral body with a possible increased length of the intercostal artery on the right (convex) side.

Adolescent↗
PubMed1995

Vertebral rotation and pedicle length asymmetry in the normal adult spine.

Rotation in the horizontal plane of vertebra T8, T9 or T10 was determined on CT scans of 25 male and 25 female patients with normal spines. The pedicle length was measured using a new method, and the right/left pedicle length index was calculated. In 38 (76%) of the patients there was vertebral rotation to the right with a mean Cobb angle of 3.0 degrees, and in 4 (8%) rotation to the left, mean Cobb angle 2.2 degrees (P < 0.01). In 8 (16%) there was no measurable rotation. The pedicle length index was greater than 1.05 in 9 subjects, between 0.95 and 1.05 in 16 and less than 0.95 in 25, indicating a predominance of longer pedicles on the left side. In 21 out of the 38 patients with vertebral rotation to the right, the left pedicle was longer than the right one (P < 0.01). The results indicate that the normal spine is afflicted with a vertebral rotation to the right in association with a longer pedicle on the left. The significance of these observations for the pathogenesis of idiopathic scoliosis remain uncertain.

Adolescent↗
PubMed1995

Horizontal plane morphometry of normal and scoliotic vertebrae. A methodological study.

Computed tomography (CT) scans are widely used for quantification of the morphology of the vertebral body and of the changes of the thoracic cage in the horizontal plane in scoliosis. So far, however, no method exists for precise quantification of the parameters of the posterior elements. We present a method for quantification on the basis of CT scans of different parameters of the morphology of both the vertebral body and posterior elements in the horizontal plane. The precision and accuracy of the method were estimated in a model study by CT scanning of a normal and a scoliotic vertebra in different, controlled, tilted positions. Moreover, in a clinical study CT scans of 19 thoracic vertebrae from non-scoliotic subjects and the apex vertebra from 40 scoliotic subjects were selected to test the applicability of the method to clinical studies. The intra- and interobserver variation of the measurements was analysed. The angle between the longitudinal axis of the vertebral body and that of the whole vertebra was used to evaluate the asymmetry of the vertebral body. The right to left pedicle width index, the right to left hemi-canal width index and the index of transverse process angles related to the axis of the vertebra were used to quantify the asymmetry of the posterior elements. The results indicate that, except for the pedicle width index, the variables under study were not significantly influenced by a 5 degrees or 10 degrees tilt ventrally, dorsally, or laterally of either the normal or the scoliotic vertebra. Hence, the method can be satisfactorily applied to longitudinal group comparisons.(ABSTRACT TRUNCATED AT 250 WORDS)

Anthropometry↗
PubMed1995

Structural vertebral changes in the horizontal plane in idiopathic scoliosis and the long-term corrective effect of spine instrumentation.

The rotation and structural changes of the apex vertebra in the horizontal plane as well as of the thoracic cage deformity were quantified by measurements on computed tomography (CT) scans from patients with right convex thoracic idiopathic scoliosis (IS). The CT scans were obtained from 12 patients with moderate scoliosis (mean Cobb angle 25.8 degrees, r 13 degrees-30 degrees) and from 33 with severe scoliosis (mean Cobb angle 46.2 degrees, r 35 degrees-71 degrees). In addition, CT scans of thoracic vertebrae from 15 patients without scoliosis were used as reference material. Ten of the scoliotic cases had had Cotrel-Dubousset instrumentation (CDI) and posterior fusion and had entered a longitudinal study on the effect of operative correction on the re-modelling of the apical vertebra. An increasingly asymmetrical vertebral body, transverse process angle, pedicle width and canal width were found in the groups with scoliosis as compared with the reference material. Vertebral rotation and rib hump index were significantly larger in patients with early and advanced scoliosis than in normal subjects. The modelling angle of the vertebral body, the transverse process angle index and the vertebral rotation in relation to the middle axis of the thoracic cage were significantly greater in patients with severe than with moderate scoliosis. The results of this longitudinal study suggest that the structural changes of the apical vertebra regress 2 years or more after CD instrumentation.

Adolescent↗
PubMed1994

Sagittal configuration of the spine and growth of the posterior elements in early scoliosis.

The early changes of the sagittal alignment of the spine and the asymmetry between the posterior and anterior elements were determined on the basis of 134 lateral and 167 anteroposterior radiographs obtained from a control group and from patients with early scoliosis. The radiographs were allocated into four groups according to the degree of the Cobb angle. In thoracic curves with a Cobb angle of more than 8 degrees, the kyphosis and the vertebral sagittal wedge angle decreased in comparison with the control group. The sagittal-wedge angle of the disc did not change significantly with increasing Cobb angle. The pedicle height in relation to the vertebral height, considered to represent the growth of the posterior element in relation to the growth of the anterior element, was not significantly different in the scoliotic groups as compared with the control group. The results indicate that changes of the sagittal configuration of the spine occur early in idiopathic scoliosis and that they are associated with disturbed growth of the vertebral body but not of the posterior elements. These findings seem to reflect a simultaneous deformation in the coronal and sagittal planes rather than a single growth disturbance in any specific plane.

Adolescent↗
PubMed1990

Vascular changes in the chest wall after unilateral resection of the intercostal nerves in the growing rabbit.

In young, growing white New Zealand rabbits the third, fourth, and fifth intercostal nerves were resected anteriorly on the right side. Six months later the animals developed structural left convex scoliosis, with a Cobb angle ranging from 15 to 31 degrees. The vascular structure changes of the anterior chest wall were evaluated by measuring surface temperature and fluorescein intensity of the pectoral muscles, and the capillary density of the pectoral and intercostal muscle and periosteal parts of the ribs after angiography. In five normal control rabbits there was neither scoliotic deformity nor significant differences in the examined vascular variables between the right and left sides. In the animals undergoing resection, the temperature of the pectoral muscle on the side of the denervation--the right side--was significantly increased (p less than 0.05), but the difference was not correlated to the degree of scoliosis. The fluorescence index was significantly greater (p less than 0.05) on the right than on the left side, this difference being fairly strongly correlated to the degree of scoliosis. The capillary densities of the costal periosteum and the intercostal and the pectoral muscle were significantly greater (p less than 0.05) on the right than on the left side, and the difference was positively correlated to the degree of scoliosis. The volume density of the periosteum of the ribs was likewise significantly greater on the right. These results demonstrate that unilateral resection of the intercostal nerves significantly increases the vascularity of the structures on the denervated side of the thorax.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Effects of rib elongation on the spine. I. Distortion of the vertebral alignment in the rabbit.

Elongation of one rib on the right side by 1 cm was achieved in two groups of adult rabbits of different age, by osteotomy and application of a metallic expander. The procedure resulted in immediate deviation of the spine in the frontal and sagittal planes, with moderate scoliosis, convex to the left, and a significant decrease in the normal cervicothoracic lordosis and thoracolumbar kyphosis. Moreover, computed tomography (CT) scanning demonstrated rotation of vertebra about the longitudinal axis relative to the anterior midline of the body, and deviation of the spinous process toward the convex, left side, of the scoliotic deformity. Rib hump developed on the right side--that of the elongated rib. These changes, which occurred simultaneously in the three planes, were less pronounced in the group of older animals. Two weeks after the operation, the distorted configuration of the spine remained unchanged. The observed changes in the alignment of the vertebrae--changes that, except for their direction on the horizontal plane, resembled those associated with idiopathic scoliosis in man--support the earlier proposed link between the early stage of development of this condition and asymmetry of rib growth.

Animals↗
PubMed1990

Effects of rib elongation on the spine. II. Correction of scoliosis in the rabbit.

Three intercostal nerves on the right side of growing rabbits were resected partially. From 1 to 3 months later, moderate left-convex thoracic scoliosis with rotation of vertebrae had developed, and the sagittal curvatures of the spine had diminished. In one group of these animals, a mechanically produced increase of 1 cm in the length of one rib on the side of the convexity resulted in an immediate correction of the scoliotic deformity, an improvement that was still evident 3 weeks after the operation. In two other groups of rabbits, a further resection of three intercostal nerves, this time on the left convex side, 1 and 2 months after the first operation, resulted in regression of scoliosis or halted its progression. These results further support a new concept in which the precipitating factor in the development of scoliosis is ascribed to asymmetric longitudinal growth of the ribs. They also suggest that regulation of the rib length could be a promising approach to the effective correction of progressive scoliosis at an early stage in man.

Animals↗
PubMed1986

The thermal emission from the skin and the vascularity of the breasts in normal and scoliotic girls.

The vascularity of the breasts was examined by thermographic and diaphanographic methods in normal and scoliotic girls. The thermal emission from the skin registered with an AGA Thermovision 750 camera (Stockholm, Sweden) on black and white Polaroid film was evaluated visually by 10 independent observers. No significant differences between the thermal images of the left and the right breast were found in the control or scoliotic groups or in girls with a right convex thoracic curve, nor was there any significant difference between the groups in this respect. Image analysis of diaphanograms of the breasts using the GOP 300 system showed a significantly greater vascularity of the left breast than of the right, both in the scoliotic series as a whole and in the subgroup with a right convex thoracic curve, but not for the reference group. The vascularity of the left breast but not of the right one was significantly greater for the girls with a right convex thoracic curve than for the control group. The results of the diaphanographic study confirm earlier observations and together provide substantial evidence that unilateral stimulation of rib growth due to a greater vascularity of the left breast and the underlying costosternal junctions might be one initiating factor in the development of right convex thoracic idiopathic scoliosis in adolescent girls.

Adolescent↗
PubMed1985

Anthropometric data relating to normal and scoliotic Scandinavian girls.

The increase in height and weight and the age at the menarche have been determined in girls with idiopathic scoliosis and in age-matched normal girls. The scoliotic girls were classified according to the position of the curve. The menarche was found to occur significantly later in girls with either a thoracolumbar or a double primary curve than in the control group; it was also significantly later in those two groups combined than in the girls with a right convex thoracic curve. At the time of the menarche, the girls with a thoracolumbar or a double primary curve were significantly taller than those in the control group. The girls with a double primary curve, and these together with girls with a thoracolumbar curve, were also significantly taller than those with a right convex thoracic curve. Those in the control group were significantly heavier, and in some age groups significantly taller, than children born during the period 1953-1958 and providing earlier Swedish research data. The average age at the menarche did not differ from that for a normal population for this country. The observed differences between the group with a right convex thoracic curve and that with a thoracolumbar or a double primary curve indicate that the pathomechanism, and even the etiology, may vary with the form of idiopathic scoliosis.

Adolescent↗
PubMedDate not supplied

The length and ash weight of the ribs of normal and scoliotic persons.

The length and ash weight of ribs were studied in cadaveric specimens from 10 women and eight men with normal spines and from 15 women with scoliosis, six of them with idiopathic right convex thoracic curves. In each case, three rib pairs were removed, those from the scoliotic women corresponding to the apex and the suprajacent and subjacent vertebrae, and those from the normal male and female subjects usually being the 7th-9th. Between the female and the male control groups, there was a significant difference in rib length asymmetry, expressed as the mean of the left minus right difference for the three rib pairs for each person. The difference in ash weight was not significant. There was a significant mean difference in rib length asymmetry between the six patients with right convex thoracic idiopathic scoliosis (concave minus convex rib) and the group of normal females (left minus right rib). Ash weight displayed no significant differences. In five of the six patients with right convex thoracic scoliosis the left ribs of the three examined pairs were on average longer than the right ribs, but the difference was not significant.

Aged↗