Body Mass Index as an Indicator of Pulmonary Dysfunction in Patients With Adolescent Idiopathic Scoliosis

Is impaired lung function related to spinal deformities in patients with adolescent idiopathic scoliosis? A systematic review and meta-analysis-SOSORT 2019 award paper

PURPOSE

Some teenagers with adolescent idiopathic scoliosis (AIS) display compromised lung function. However, the evidence regarding the relations between pulmonary impairments and various spinal deformity parameters in these patients remains unclear, which affects clinical management. This systematic review and meta-analysis aimed to summarize the associations between various lung function parameters and radiographic features in teenagers with AIS.

METHODS

A search of PubMed, Embase, PEDro, SPORTDiscus, CINAHL, Cochrane Library, and PsycINFO (from inception to March 14, 2022) without language restriction. Original studies reporting the associations between lung function and spinal deformity in patients with AIS were selected. Independent reviewers extracted data and evaluated the methodological quality of the included studies according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Pearson correlation and 95% confidence intervals were calculated using random-effects meta-analysis.

RESULTS

Twenty-seven studies involving 3162 participants were included. Limited-quality evidence supported that several spinal parameters were significantly related to lung function parameters (e.g., absolute value and percent of the predicted forced vital capacity (FVC; %FVC), forced expiratory volume in one second (FEV₁; %FEV₁), and total lung capacity (TLC; %TLC)) in AIS patients. Specifically, meta-analyses showed that main thoracic Cobb angles in the coronal plane were significantly and negatively related to FVC (r =  - 0.245), %FVC (r =  - 0.302), FEV₁ (r =  - 0.232), %FEV₁ (r =  - 0.348), FEV₁/FVC ratio (r =  - 0.166), TLC (r =  - 0.302), %TLC (r =  - 0.183), and percent predicted vital capacity (r =  - 0.272) (p < 0.001). Similarly, thoracic apical vertebral rotation was negatively associated with %FVC (r =  - 0.215) and %TLC (r =  - 0.126) (p < 0.05). Conversely, thoracic kyphosis angles were positively related to %FVC (r = 0.180) and %FEV₁ (r = 0.193) (p < 0.05).

CONCLUSION

Larger thoracic Cobb angles, greater apical vertebral rotation angle, or hypokyphosis were significantly associated with greater pulmonary impairments in patients with AIS, although the evidence was limited. From a clinical perspective, the results highlight the importance of minimizing the three-dimensional spinal deformity in preserving lung function in these patients. More research is warranted to confirm these results.

The Prevalence of Scoliosis Screening Positive and Its Influencing Factors: A School-Based Cross-Sectional Study in Zhejiang Province, China

Objective

Early detection of scoliosis is of great significance to patients with scoliosis and the whole society. This paper aims to learn the prevalence of scoliosis screening positive among students in primary and secondary schools and to explore the influencing factors.

Methods

In 2019, a stratified cluster sampling technique was employed in this school-based cross-sectional study. The sampling covers all prefecture-level cities in Zhejiang Province. Based on the whole class, at least 80 students in each grade of primary school, junior high school, and senior high school were selected. Physical examination and scoliosis screening were performed in the school-based investigation. The distribution of demographic characteristics and nutritional status of children and adolescents with scoliosis screening positive were explored.

Results

A total of 45,547 students were screened. The overall prevalence of children and adolescents with scoliosis screening positive were 3.9%. Higher prevalence of scoliosis screening positive was found in students living in urban area (4.1%), women students (4.1%), students with low weight (5.3%) (p < 0.05), and the prevalence increased with age (p < 0.05). In logistic analysis, we found age (OR = 1.145; 95% Cis: 1.128, 1.162), gender (OR = 1.118; 95% Cis: 1.016, 1.230) and low weight (OR = 1.48; 95% Cis: 1.25, 1.751) were the influencing factors for prevalence of scoliosis screening positive (p < 0.05).

Conclusions

There were no disparities between living areas, but there was a significant difference between genders, among different ages, and among different nutritional statuses of children and adolescents with or without scoliosis screening positive. In multi-analysis, age, gender, and low weight were the influencing factors for the prevalence of scoliosis screening positive. Age and gender-specific scoliosis screening strategies and nutritional public health policies for children and adolescents are needed.

Pulmonary function in children and adolescents with untreated idiopathic scoliosis: a systematic review with meta-regression analysis

BACKGROUND CONTEXT

One of the controversies in untreated idiopathic scoliosis is the influence of curve size on respiratory function. Whereas scoliosis patients with curves over 90 to 100 degrees are agreed to be at risk for cardiorespiratory failure in later life, the impairment of curves below 90 degrees is generally considered mild. Although various studies showed that pulmonary function is affected in patients with scoliosis, quantification of the relation between curve size and pulmonary function is lacking.

PURPOSE

This systematic review with meta-regression analysis aims to characterize the relation between pulmonary function tests and scoliosis severity in children and adolescents with idiopathic scoliosis.

STUDY DESIGN

Systematic review with meta-regression analysis.

METHODS

Pubmed, Embase, Cochrane, and CINAHL were systematically searched until November 3, 2020, for original articles that reported (1) severity of scoliosis quantified in Cobb angle, and (2) pulmonary function tests in children and adolescents with untreated idiopathic scoliosis. Exclusion criteria were other types of scoliosis, non-original data, post-treatment data, and case reports. All study designs were included, and relevant study details and patient characteristics were extracted. The primary outcome was the effect of Cobb angle on pulmonary function as expressed by the slope coefficient of a linear meta-regression analysis.

RESULTS

A total of 126 studies, including 8,723 patients, were retrieved. Meta-regression analysis revealed a statistically significant inverse relation between thoracic Cobb angle and absolute and predicted forced vital capacity in 1 second, forced vital capacity, vital capacity, and total lung capacity. For these outcomes, the slope coefficients showed a decrease of 1% of the predicted pulmonary function per 2.6 to 4.5 degrees of scoliosis. A multivariable meta-regression analysis of potential confounders (age, year of publication, and kyphosis) hardly affected the majority of the outcomes.

CONCLUSION

This meta-regression analysis of summary data (means) from 126 studies showed an inverse relationship between the thoracic Cobb angle and pulmonary function. In contrast to previous conclusions, the decline in pulmonary function appears to be gradual over the full range of Cobb angles between <20 and >120 degrees. These findings strengthen the relevance of minimizing curve progression in children with idiopathic scoliosis.

Do Heavier Patients With Adolescent Idiopathic Scoliosis Have More Preserved Thoracic Kyphosis and Pulmonary Function?

STUDY DESIGN

Retrospective.

OBJECTIVES

We aimed to determine if heavier patients with adolescent idiopathic scoliosis (AIS) had more preserved thoracic kyphosis (TK), and as a result, more preserved pulmonary function.

SUMMARY OF BACKGROUND DATA

Some believe that childhood weight is predictive of adult sagittal plane parameters, with heavier children having greater TK as adults. Generally, thoracic scoliosis is coupled with loss of TK, which is associated with worsening pulmonary function.

METHODS

A total of 142 patients with AIS and a structural main thoracic curve were analyzed. We excluded patients with structural proximal thoracic curves (Lenke 2 and 4). Standing preoperative radiographs, pulmonary function tests, and preoperative body mass indices (BMIs) were reviewed. The main thoracic Cobb angle, T2-T12 TK, percentage predicted forced vital capacity (FVC) and BMI were recorded. Spearman correlation was determined. Linear regression analysis used FVC as the primary outcome and BMI, TK, and Cobb angle as the independent variables. BMI categories were overweight/obese (BMI ≥25) and normal (BMI <25). Wilcoxon rank-sum tests were performed to detect a difference in TK and BMI between the 2 groups. The Cobb angles between the two groups were analyzed by t tests.

RESULTS

Demonstrated correlations included BMI and FVC (0.37, p ≤.01), FVC and TK (0.26, p <.01), BMI and TK (0.23, p = .01), and FVC and Cobb angle (-0.23, p = .01). Linear regression revealed that Cobb angle (p ≤.01), TK (p <.01), and BMI (p <.01) remained statistically significant predictors of FVC. Wilcoxon rank-sum tests revealed a statistically significant difference between TK (p = .03) and FVC (p <.01) in the overweight/obese group and the normal group, with the overweight/obese group having greater values for both TK and FVC. The Cobb angles between the overweight/obese and normal group were not significantly different (p = .72).

CONCLUSIONS

Heavier AIS patients have greater values of TK and percentage predicted FVC.

LEVEL OF EVIDENCE

Level III.

Risk Factors of Impaired Pulmonary Function in Arthrogryposis Multiplex Congenital Patients With Concomitant Scoliosis: A Comparison With Adolescent Idiopathic Scoliosis

STUDY DESIGN

A retrospective study.

OBJECTIVE

To investigate the severity of pulmonary function impairment for arthrogryposis multiplex congenital (AMC) patients with concomitant scoliosis and to determine risk factors associated with the impaired pulmonary function in these patients.

SUMMARY OF BACKGROUND DATA

AMC patients are generally believed to have impaired pulmonary function. However, the severity of respiratory morbidity and the associated risk factors have not been reported.

METHODS

The pulmonary function tests data including the percentage predicted values of forced vital capacity (%FVC), forced expiratory volume in 1 second (%FEV1), and the ratio of FEV1 to FVC (%FEV1/FVC) were reviewed and compared for 48 AMC patients with secondary scoliosis and 48 patients with adolescent idiopathic scoliosis. The radiographic parameters of coronal and sagittal plane deformities and body mass index (BMI) were measured and correlated with impaired pulmonary function in these AMC patients.

RESULTS

AMC patients with concomitant scoliosis had significant lower mean %FVC, %FEV1, and %FEV1/FVC than adolescent idiopathic scoliosis patients (48.8 vs. 70.3 for %FVC, P < 0.001; 45.3 vs. 69.7 for %FEV1, P < 0.001; 92.1 vs. 96.9 for %FEV1/FVC, P < 0.05, respectively). Seventy percent of AMC patients had severe pulmonary function impairment. A positive correlation was found between BMI and %FVC and %FEV1 (P < 0.01) and between hypokyphosis and %FVC and %FEV1 (P < 0.05). A negative correlation was found between coronal angle and pulmonary function (P < 0.05). Multiple regression analysis showed that all of the three variables were independent predictors associated with a reduced pulmonary function. With a combination of these variables, the multiple regression model could account for 38.7% of the variance in %FVC and 41.5% in %FEV1.

CONCLUSION

There exists severe impairment of pulmonary function in AMC patients with concomitant scoliosis. The scoliotic curve, hypokyphosis, and BMI were independent risk factors associated with the pulmonary dysfunction in these patients. As the majority of the variability of impaired pulmonary function tests are still poorly understood, more risk factors await to be uncovered in future studies.

LEVEL OF EVIDENCE

4.

A software program to measure the three-dimensional length of the spine from radiographic images: Validation and reliability assessment for adolescent idiopathic scoliosis

BACKGROUND AND OBJECTIVE

The aim of this study was to validate a new program which aims at measuring the three-dimensional length of the spine's midline based on two calibrated orthogonal radiographic images. The traditional uniplanar T1-S1 measurement method is not reflecting the actual three dimensional curvature of a scoliotic spine and is therefore not accurate. The Spinal Measurement Software (SMS) is an alternative to conveniently measure the true spine's length.

METHODS

The validity, inter- and intra-observer variability and usability of the program were evaluated. The usability was quantified based on a subjective questionnaire filled by eight participants using the program for the first time. The validity and variability were assessed by comparing the length of five phantom spines measured based on CT-scan data and on radiographic images with the SMS. The lengths were measured independently by each participant using both techniques.

RESULTS

The SMS is easy and intuitive to use, even for non-clinicians. The SMS measured spinal length with an error below 2 millimeters compared to length obtained using CT scan datasets. The inter- and intra-observer variability of the SMS measurements was below 5 millimeters.

CONCLUSIONS

The SMS provides accurate measurement of the spinal length based on orthogonal radiographic images. The software is easy to use and could easily integrate the clinical workflow and replace current approximations of the spinal length based on a single radiographic image such as the traditional T1-S1 measurement.