An analysis of the effect of the Zielke operation on the rib cage of S-shaped curves in idiopathic scoliosis

Changes of concave and convex rib-vertebral angle, angle difference and angle ratio in patients with right thoracic adolescent idiopathic scoliosis

The aim of this study is to describe the radiological changes in rib-vertebral angles (RVAs), rib-vertebral angle differences (RVADs), and rib-vertebral angle ratios (RVARas) in patients with untreated right thoracic adolescent idiopathic scoliosis and to compare with the normal subjects. The concave and convex RVA from T1 to T12, the RVADs and the RVARas were measured on AP digital radiographs of 44 female patients with right convex idiopathic scoliosis and 14 normal females. Patients were divided into three groups: normal subjects (group 1), scoliotic patients with Cobb's angle equal or <30° (group 2) and scoliotic patients with Cobb's angle over 30° (group 3). Overall values (mean ± SD) of the RVAs on the concave side were 90.5° ± 17° in group 1, 90.3° ± 15.8° in group 2 and 88.8° ± 15.4° in group 3. On the convex side, values were 90.0° ± 17.3° in group 1, 86.3° ± 13.7° in group 2 and 80.7° ± 14.4° in group 3. Overall values (mean ± SD) of the RVADs at all levels were 0.5° ± 0.7° in group 1, 4.0° ± 4.8° in group 2 and 8.0° ± 4.0° in group 3. The RVARa values (mean ± SD) at all levels was 1.008° ± 0.012° in group 1, 1.041° ± 0.061° in group 2 and 1.102° ± 0.151° in group 3. RVAD and RVARa values in the scoliotic segment were greater in patients with untreated scoliosis over 30° than in patients with an untreated deformity of <30° or normal subjects. A significant effect between groups was observed for the RVA, RVAD and RVARa variables. Measurement of RVA, RVAD and RVARa should not only be performed at and around the apex of a thoracic spinal deformity, but also extended to the whole thoracic spine.

A segmental radiological study of the spine and rib--cage in children with progressive infantile idiopathic scoliosis

BACKGROUND

The role of rib cage in the development of progressive infantile idiopathic scoliosis (IIS) has not been studied previously. No report was found for rib growth in children with IIS. These findings caused us to undertake a segmental radiological study of the spine and rib-cage in children with progressive IIS. The aim of the present study is to present a new method for assessing the thoracic shape in scoliotics and in control subjects and to compare the findings between the two groups.

MATERIALS AND METHODS

In the posteroanterior (PA) spinal radiographs of 24 patients with progressive IIS, with a mean age of 4.1 years old, the Thoracic Ratios (TRs) (segmental convex and concave TRs), the Cobb angle, the segmental vertebral rotation and vertebral tilt were measured. In 233 subjects, with a mean age of 5.1 years old, who were used as a control group, the segmental left and right TRs and the total width of the chest (left plus right TRs) were measured in PA chest radiographs. Statistical analysis included Mann-Whitney, Spearman correlation coefficient, multiple linear regression analysis and ANOVA.

RESULTS

The comparison shows that the scoliotic thorax is significantly narrower than that of the controls at all spinal levels. The upper chest in IIS is funnel-shaped and the vertebral rotation at T4 early in management correlates significantly with the apical vertebral rotation at follow up.

CONCLUSION

The IIS thorax is narrower than that of the controls, the upper chest is funnel-shaped and there is a predictive value of vertebral rotation at the upper limit of the thoracic curve of IIS, which reflects, impaired rib control of spinal rotation possibly due to neuromuscular factors, which contribute also to the funnel-shaped chest.

External fixation for dynamic correction of severe scoliosis

BACKGROUND CONTEXT

The ideal treatment for scoliosis may be the correction of the factors that cause the disease. An external fixation device was used in 12 patients to achieve a correction by dynamic distraction, compression and derotation of the curve. Follow-up was done over a 7-year period.

PURPOSE

To describe the treatment of inflexible and severe scoliosis by special correction with external fixation.

STUDY DESIGN/SETTING

This was a prospective, longitudinal and descriptive study, with a follow-up period of 7 years.

PATIENT SAMPLE

Twelve patients (9 female, 3 male) from the National Orthopaedic Institute Spine Service in external consultation.

OUTCOME MEASURES

Radiographic measurements with the scoliosis angulation of Cobb's method were used before surgery, after surgery and in the final follow-up period.

METHODS

The surgical procedure consisted of two stages, anterior and posterior approach, dissectomies, vertebrectomy at the apex, spinal column shortening and the placement of an external stabilization device. Progressive correction of the curve was done by a daily increase in distraction (3 mm/day). When the correction was finished, a different internal fixation device was used to maintain the correction. The time between initial treatment and final correction was 50 days. Ten thoracic curves, one thoracolumbar curve and one lumbar curve were treated, with an average of 93 degrees. All patients had kyphosis with an average of 89 degrees. Vertebral rotation was not found in two patients.

RESULTS

Average correction of scoliosis was 52.9% and of kyphosis, 29%. Vertebral rotation in eight cases was corrected. There were no neurological irreversible lesions in any patient. There was one infection. Using an evaluation result scale, there were 2 excellent, 6 good and 4 fair outcomes. The average loss of correction was 5 degrees.

CONCLUSION

The results suggest that the use of an external stabilization device with controlled compression on the convexity and distraction on the concavity of the curve can achieve a correction of up to 50% in scoliosis, 30% in kyphosis and 1 degree in the rotation of the spine.

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.

Prediction of scoliotic cobb angle with the use of the scoliometer

STUDY DESIGN

A prospective study was conducted in a young homogenous adolescent population, with the use of the scoliometer.

OBJECTIVES

To create a mathematic formula that provides the accurate Cobb angle of idiopathic scoliosis with the use of the scoliometer only.

SUMMARY OF BACKGROUND DATA

The scoliometer is an accepted method for detection and evaluation of scoliosis during screening programs. To the author's knowledge, there are no previous methods and formulas to estimate the approximate Cobb angle using only the scoliometer.

METHODS

Several clinical (scoliometer value, age, and sex) and radiographic (Cobb angle, Perdriolle of and apical vertebra, Risser iliac apophysis classification) parameters from 442 (4.37%) of 10,109 screened adolescents who had a scoliometer value of at least 7 degrees were taken and correlated using the simple and multiple linear regression analysis.

RESULTS

Cobb angle and scoliometer value were statistically significantly correlated to each other. Two mathematic formulas were created to predict the Cobb angle of the thoracic and lumbar scoliosis, with similar sensitivity and accuracy. The thoracic and lumbar scoliometer values were statistic significantly correlated with the thoracic and lumbar Cobb angle (P = 0.0254 and P = 0.0015, respectively). The lumbar scoliometer value was significantly correlated with lumbar apical vertebra Perdriolle value. Also, the thoracic and lumbar Cobb angles were significantly correlated with thoracic and lumbar apical vertebra (P = 0.0001 and P = 0.0015, respectively).

CONCLUSIONS

In the present study, the authors have constructed two mathematic formulas, which provide accurately the scoliotic Cobb angle in young adolescents using only the scoliometer with a deviation of 5.63 degrees thoracic curves and 5.79 degrees for lumbar curves. The authors recommended that all physicians engaged in scoliosis screening programs use the scoliometer based on the mathematic formulas that the authors developed. They believe that this method will reduce the cost of school screening programs, the overdiagnosis, and the unnecessary exposure to irradiation of this young population in the future.