Histologic, risser sign, and digital skeletal age evaluation for residual spine growth potential in Chinese female idiopathic scoliosis

Contribution of postoperative vertebral remodeling to reversal of vertebral wedging and prevention of correction loss in patients with adolescent Scheuermann's kyphosis

OBJECTIVE

This study aimed to investigate reversal of vertebral wedging and to evaluate the contribution of vertebral remodeling to correction maintenance in patients with adolescent Scheuermann's kyphosis (SK) after posterior-only instrumented correction.

METHODS

A retrospective cohort study of patients with SK was performed. In total, 45 SK patients aged 10-20 years at surgery were included. All patients received at least 24 months of follow-up and had Risser sign greater than grade 4 at latest follow-up. Patients with Risser grade 3 or less at surgery were assigned to the low-Risser group, whereas those with Risser grade 4 or 5 were assigned to the high-Risser group. Radiographic data and patient-reported outcomes were collected preoperatively, immediately postoperatively, and at latest follow-up and compared between the two groups.

RESULTS

Remarkable postoperative correction of global kyphosis was observed, with similar correction rates between the two groups (p = 0.380). However, correction loss was slightly but significantly less in the low-Risser group during follow-up (p < 0.001). The ratio between anterior vertebral body height (AVBH) and posterior vertebral body height (PVBH) of deformed vertebrae notably increased in SK patients from postoperation to latest follow-up (p < 0.05). Loss of correction of global kyphosis was significantly and negatively correlated with increased AVBH/PVBH ratio. Compared with the high-Risser group, the low-Risser group had significantly greater increase in AVBH/PVBH ratio during follow-up (p < 0.05). The two groups had similar preoperative and postoperative Scoliosis Research Society-22 questionnaire scores for all domains.

CONCLUSIONS

Obvious reversal in wedge deformation of vertebrae was observed in adolescent SK patients. Patients with substantial growth potential had greater vertebral remodeling and less correction loss. Structural remodeling of vertebral bodies has a positive effect and protects against correction loss. These results could be help guide treatment decision-making.

Correlation of collagen X biomarker (CXM) with peak height velocity and radiographic measures of growth in idiopathic scoliosis

STUDY DESIGN

Prospective comparative study.

OBJECTIVES

Evaluate the correlation of CXM with established measures of growth. Theoretically higher CXM levels would correlate with rapid longitudinal bone growth and lower levels with growth cessation. Assessment of growth status in patients with pediatric spinal deformity is critical. The current gold standards for assessing skeletal maturity are based on radiographic measures and have large standard errors (SE). Type X collagen (COLX) is produced in the growing physis during enchondral ossification. CXM is a COLX breakdown product that can be measured in blood products. CXM, thus, is a direct measure of enchondral ossification.

METHODS

IRB-approved prospective study. Q6mo anthropometrics and spine PA biplanar slot scanner images including the hand were assessed for major Cobb, Risser score (RS), triradiate cartilage status (TRC), Greulich and Pyle bone age (BA), and Sanders Score (SS). Serial dried blood spots (DBS) to obtain CXM levels were collected 3 consecutive days Q1-2 months based on SS.

RESULTS

47 idiopathic scoliosis patients, Cobb ≥ 20 were enrolled. Mean enrollment age was 11.8 years (range 7.1-16.6 years). 3103 DBS samples were assayed in quadruplicate. CXM results were highly reproducible with a 3% intraassay coefficient of variation (CV), and 12% interassay CV%. The CXM 3-day average was significantly correlated with BA R = 0.9, p < 0.001, RS R = 0.6, p < 0.001, SS R = 0.7, p < 0.001 and with height R = 0.7, p < 0.001. No patient with a CXM level < 5 ng/ml had remaining growth.

CONCLUSION

CXM is the first identifiable biomarker specific to longitudinal bone growth. Early results indicate that it is a patient-specific, real-time measure of growth velocity with high correlation to the established anthropometric and radiographic measures of growth. It is predictive of cessation of growth. It is highly reproducible with a low SE. Long-term follow-up is required to determine the ability of CXM to guide clinical decision-making.

Brace Treatment in Adolescent Idiopathic Scoliosis Patients with Curve Between 40° and 45°: Effectiveness and Related Factors

OBJECTIVE

To investigate effectiveness of brace treatment in patients with adolescent idiopathic scoliosis with curve between 40° and 45° and to determine predictive factors associated with bracing outcome.

METHODS

Bracing was used to treat 90 patients with curve >40 degrees. Factors including Risser sign, age, sex, curve pattern, curve magnitude, and initial curve correction were compared between patients with curve improvement and patients with curve progression. Logistic regression analysis was used to determine the independent predictors of curve progression.

RESULTS

Curve was improved in 34 (37.8%) patients and stabilized in 12 (13.3%) patients. Remarkable curve progression >50 degrees was observed in 44 (48.9%) patients. Intergroup comparison showed significant differences between the 2 groups in terms of age (12.3 ± 1.4 years vs. 13.2 ± 1.6 years, P = 0.01), initial curve correction (2.2% ± 5.4% vs. 19.7% ± 12.2%, P < 0.001), and curve pattern (P = 0.03). Logistic regression analysis showed that initial curve correction of <10% (odds ratio = 12.82, P < 0.001) and Risser grade of 0 (odds ratio = 1.46, P = 0.04) were significant indicators of curve progression.

CONCLUSIONS

Bracing may produce a favorable outcome in certain patients with curve between 40° and 45°. It should be cautiously used in this situation, as there was a higher probability of bracing failure. It is important to differentiate patients at high risk of curve progression at an early stage to avoid overtreatment.

Scoliosis vertebral growth plate histomorphometry: Comparisons to controls, growth rates, and compressive stresses

Scoliosis progression in skeletally immature patients depends on remaining growth. Relationships between vertebral growth plate histomorphometry, growth rates, and mechanical stresses have been reported in several animal studies. Hypertrophic zone heights and chondrocyte heights have been used to assess treatments that aim to modulate growth. The purpose of this study was to determine whether human vertebral physeal hypertrophic zone and cell heights differed between two groups: Severe scoliosis and autopsy controls. Severity was defined at time of surgical planning by curve magnitude and curve stiffness. Physeal samples were obtained from the convex side apex, and from the concave side when feasible. Histologic sections were prepared, and digital images were used to measure hypertrophic zone height, cell height, and cell width. Thirteen spinal deformity patients were included, mean curve magnitude 67° (±23). Etiologies were juvenile and adolescent idiopathic, congenital, neurofibromatosis, neuromuscular, and Marfan syndrome. Five age-matched autopsy specimens without scoliosis served as controls. Results were presented by etiology, then all convex scoliosis specimens were combined and compared to controls. Zone heights for scoliosis, convex side, and controls were 152 µm (±34) and 180 µm (±42) (p = 0.21), cell heights 8.5 µm (±1.1) and 12.8 µm (±1.2) (p < 0.0005), and cell widths 14.9 µm (±1.5) and 15.0 µm (±2.5), respectively. Human values were compared to published animal models and to a quantitative theory of a stress ̶ growth curve. This quantification of vertebral physeal structures in scoliosis may be expected to help assess theories of progression and potential treatments using growth modulation. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2450-2459, 2018.

Low body mass index can be predictive of bracing failure in patients with adolescent idiopathic scoliosis: a retrospective study

PURPOSES

To determine the relationship between low body mass index (BMI) and the outcome of brace treatment in patients with adolescent idiopathic scoliosis (AIS).

METHODS

350 braced female AIS patients were included in this study. The baseline characteristics of the patient were recorded at their first visit, including age, Risser sign, digital skeletal age, BMI, curve pattern, and curve magnitude. Underweight was defined as lower than the 5th percentile of the sex- and age-specific BMI. The treatment was considered as a failure if the curve progressed more than 5°, or if patients underwent surgery. According to the final outcome of brace treatment, the cohort was divided into the success group and the failure group. A logistic regression model was created to determine the independent predictors of the bracing outcome.

RESULTS

24.5% (86/350) of the patients were identified as underweight at their initial visit, which was significantly higher than the rate of 13.1% (46/350) at the final follow-up (p < 0.001). At the initial visit of the patients, the rate of underweight was 17.6% (45/255) in the success group, which was significantly lower than the rate of 43.1% (41/95) in the failure group (p < 0.001). Logistic regression analysis showed that low BMI was significantly associated with bracing failure (p < 0.001).

CONCLUSION

The low BMI could be predictive of bracing failure in AIS patients, which should be taken into account when surgeons prescribe brace treatment to such patients.

Comparison of radiographic sagittal spinopelvic alignment between skeletally immature and skeletally mature individuals with Scheuermann's disease

PURPOSE

The aim of this study was to compare radiographic sagittal spinopelvic parameters between skeletally immature and skeletally mature patients with Scheuermann's disease (SD).

METHODS

Cross-sectional analysis of standing postero-anterior and lateral radiographs of the spine of patients with SD was performed. Sagittal vertical axis (SVA), thoracic kyphosis (TK), thoracolumbar kyphosis (TLK), lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), and sacral slope (SS) were measured on the lateral radiographs. Risser's sign was assessed on the postero-anterior radiographs. All of the parameters measured were compared between skeletally immature (Risser's sign 0-3) versus mature patients (Risser's sign 5). PI, PT, and SS in both groups were compared to PI, PT, and SS reported for normal children, adolescents, and adults.

RESULTS

Sixty-six patients with SD (33 immature and 33 mature) were retrospectively reviewed and included in the study. There was no significant difference between the two groups of SD patients in: SVA (-16.6 vs. -22.9 mm, p = 0.74), TK (57.8° vs. 56°, p = 0.66), TLK (7.8° vs. 11.7º, p = 0.14), LL (63.2° vs. 62.2°, p = 0.74), PI (36.7° vs. 39.4°, p = 0.20), PT (3.8° vs. 7.3°, p = 0.10), and SS (32.8° vs. 32.1°, p = 0.75). Both, the immature and mature group of SD patients presented significantly lower PI and SS than normal children, adolescents, and adults, and significantly lower PT than normal adults.

CONCLUSIONS

There is no significant difference in sagittal spinopelvic parameters between skeletally immature and mature subjects with SD. Pelvic incidence in both groups of SD patients was significantly lower than PI in normal children, adolescents, and adults. This challenges the role of PI in predicting desired LL in patients with SD.

Risk Factors for Coronal Decompensation After Posterior Spinal Instrumentation and Fusion in Adolescent Idiopathic Scoliosis

STUDY DESIGN

Retrospective review of multicenter data set with adolescent idiopathic scoliosis (AIS) patients with at least 2 years of follow-up after posterior spinal instrumentation and fusion (PSIF).

OBJECTIVES

The purpose of this study is to investigate risk factors for coronal decompensation 2 years after PSIF for AIS.

SUMMARY OF BACKGROUND DATA

Coronal decompensation is a potential complication of spinal instrumentation for AIS. This can result in problems requiring revision surgery.

METHODS

Demographic, clinical, and radiographic measures were reviewed on 890 identified patients. Coronal decompensation was defined as a change farther away from midline from 6 weeks postoperatively to 2 years in any one of the following radiographic parameters: change in coronal balance >2 cm; change in coronal position of the lowest instrumented vertebra (LIV) >2 cm; change in thoracic trunk shift >2 cm; or change in LIV tilt angle >10°. Patients with decompensation were compared to those without. The relationship between the LIV and lowest end vertebra (LEV) was examined as an independent variable.

RESULTS

Two years postoperation, 6.4% (57/890) of patients exhibited coronal decompensation. Multivariate regression revealed that decompensated patients were twice as likely to be male, have lower preoperative Risser score, and lower percentage major curve correction. The relationship between the LIV and LEV as well as quality of life surveys were not significantly different between decompensated and nondecompensated patients at 2 years.

CONCLUSIONS

Two years after PSIF, 6.4% of patients with AIS exhibit radiographic coronal decompensation. Although this study did not demonstrate a significant association between the relationship of LIV and LEV and decompensation 2 years postoperation, results of this study indicate that skeletal immaturity, male gender, and less correction of the major curve may be related to higher rates of coronal decompensation.

Predicting the peak growth velocity in the individual child: validation of a new growth model

Predicting the peak growth velocity in an individual patient with adolescent idiopathic scoliosis is essential or determining the prognosis of the disorder and timing of the (surgical) treatment. Until the present time, no accurate method has been found to predict the timing and magnitude of the pubertal growth spurt in the individual child. A mathematical model was developed in which the partial individual growth velocity curve was linked to the generic growth velocity curve. The generic curve was shifted and stretched or shrunk, both along the age axis and the height velocity axis. The individual age and magnitude of the PGV were obtained from the new predicted complete growth velocity curve. Predictions were made using 2, 1.5, 1 and 0.5 years of the available longitudinal data of the individual child, starting at different ages. The predicted values of 210 boys and 162 girls were compared to the child’s own original values of the PGV. The individual differences were compared to differences obtained when using the generic growth velocity curve as a standard. Using 2 years of data as input for the model, all predictions of the age of the PGV in boys and girls were significantly better in comparison to using the generic values. Using only 0.5 years of data as input, the predictions with a starting age from 13 to 15.5 years in boys and from 9.5 to 14.5 years in girls were significantly better. Similar results were found for the predictions of the magnitude of the PGV. This model showed highly accurate results in predicting the individual age and magnitude of the PGV, which can be used in the treatment of patients with adolescent idiopathic scoliosis.

Correlation and comparison of Risser sign versus bone age determination (TW3) between children with and without scoliosis in Korean population

BACKGROUND

Most studies comparing the Risser staging for skeletal maturity are representing the American or European standards which are not always applicable to Asian population who have relatively less height and body mass. There is no article available that compares the Risser sign and bone age correlation between patients with idiopathic scoliosis and patients without scoliosis.

MATERIALS AND METHODS

To analyze and compare the skeletal age with the Risser sign between scoliosis and non-scoliosis group, a cross-sectional study was done in 418 scoliosis (untreated, bracing or surgically) and 256 non-scoliosis children of Korean origin. Relationship was found in both groups using Pearson correlation test.

RESULTS

In scoliosis group, Pearson correlation exhibited significant correlation (p < 0.01) between Risser sign and chronological age (r2 = 0.791 for girls, 0.787 for boys) and Risser sign and TW3 age (r2 = 0.718 for girls, 0.785 for boys). Non-scoliosis group also showed significant relationship (p < 0.01) between Risser sign and chronological age (r2 = 0.893 for girls, 0.879 for boys) and Risser sign and TW3 age (r2 = 0.913 for girls, 0.895 for boys). Similarly, comparing Cobb angles of each patient according to their Risser staging, exhibited that if scoliosis remains untreated Cobb angle will increase with the increase in their Risser staging (r2 = 0.363 for girls, 0.443 for boys; p < 0.01).

CONCLUSION

Our results showed that chronological age is equally as reliable as skeletal age method to compare with Risser sign, and therefore, we do not mean to imply that only the Risser sign compared with skeletal age should be considered in the decision making in idiopathic as well as non-scoliosis patients of Korean ethnicity. Concomitant indicators such as menarchal period, secondary sex characteristics, and recent growth pattern will likely reinforce our data comparing Risser sign with skeletal age in decision making.

Assessment of angle velocity in girls with adolescent idiopathic scoliosis

Background

Although it has been demonstrated that the peak height velocity (PHV) is a predictive factor of progression in adolescent idiopathic scoliosis (AIS), little is known about the usefulness of angle progression in clinical practice. The purpose of this study was to establish a relationship between height and angle velocities, as well as to determine if peak angle velocity (PAV) occurs at the same time than PHV.

Methods

A retrospective study of a cohort of girls with idiopathic scoliotic curves greater than 10°. Data of 132 girls who participated in a previous retrospective study about growth in AIS were used to calculate height and angle velocities. Relationship between height and angle velocities was estimated by the use of a Linear Mixed Model.

Results

PHV and PAV take place simultaneously 1 year before menarche in progressive curves managed with a brace in AIS. Changes in angle velocity are influenced by changes in height growth velocity, in such a way that as from 6 months post-menarche, height growth velocity in this group of girls estimates curve progression velocity (β-coefficient -0.88, p = 0.04).

Conclusion

As from 6 months post-menarche, there is an inverse relationship between height velocity and curve progression in the group of AIS girls with progressive curves managed with a brace. Because height velocity is decreasing from 1 year before menarche, this finding corroborates that at the end of puberty, there is still a risk of progression in this group of girls despite bracing. The assessment of both height and angle velocity might be useful in clinical practice at the time of assessing brace effectiveness and how long bracing has to be indicated.

Correlation of Risser sign, radiographs of hand and wrist with the histological grade of iliac crest apophysis in girls with adolescent idiopathic scoliosis

STUDY DESIGN

A correlation analysis between histologic grade (HG) of iliac crest apophysis and skeletal age assessments.

OBJECTIVE

To study the correlation between HGs of iliac crest apophysis and the skeletal age of hand and wrist, digital skeletal age (DSA), and Risser sign in the girls with adolescent idiopathic scoliosis (AIS).

SUMMARY OF BACKGROUND DATA

The evaluation of the remaining growth of the patients clinically and radiologically is highly significant in predicting the curve progression and thus influencing the treatment strategy in AIS.

METHODS

Fifty-three AIS girls with a mean age of 14.0 years undergoing corrective posterior spinal surgery and instrumentation with autogenous bone graft were recruited. Menarche status was recorded while the skeletal age of hand and wrist, DSA, and Risser grade were evaluated radiologically. Using a standardized HG of proliferative chondrocyte zone of the iliac crest apophysis, correlation between the HGs and the radiologic and clinical skeletal maturity parameters was analyzed.

RESULTS

The HGs were negatively correlated with the radiologic parameters with the highest correlation coefficient between HGs and skeletal age of hand and wrist. The negative correlation between HGs and the 2 clinical parameters was significant and could be enhanced by combining with the radiologic parameters. No proliferative chondrocyte zone of the apophysis was detected when patients were either over 16 years of skeletal age or Risser grade 5, as well as 2-year postmenarche or over 15 years of chronological age in patients with DSA stage III and Risser grade 4.

CONCLUSION

Radiologic skeletal age of the wrist and digits can provide important information for maturity assessment in girls with AIS. It can also enhance the sensitivity of clinical parameters in determining the remaining growth potential.