Correlation of preoperative deformity magnitude and pulmonary function tests in adolescent idiopathic scoliosis

Pulmonary function in patients with idiopathic scoliosis 40 years after diagnosis

BACKGROUND CONTEXT

Pulmonary function in patients with scoliosis has been a topic of concern, with some reports of markedly decreased ventilatory function leading to disability and increased mortality in patients with severe scoliosis. Only limited data is available concerning pulmonary function in adult patients with scoliosis.

PURPOSE

To report the long-term pulmonary function (PF) in patients diagnosed with idiopathic scoliosis (IS) compared with an age-matched population using extended pulmonary function testing (EPFT).

STUDY DESIGN/SETTING

Retrospective clinical follow-up.

PATIENT SAMPLE

A total of 177 patients seen at our institution from 1972 to 1983 for a pediatric spinal deformity were assessed for inclusion in the study. About 77/129 eligible patients with IS (60%) partook in a clinical examination including radiographs, and EPFT.

OUTCOME MEASURES

The EPFT values included forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), FEV1/FVC ratio, vital capacity (VC), total lung capacity (TLC), residual volume (RV), RV/TLC ratio, diffusion capacity of carbon monoxide (DLco), carbon monoxide transfer coefficient (KCO) and alveolar volume (VA). Results were expressed with z-scores derived from height and arm span normative data. Z-scores were calculated as z-score=Measured PF-Predicted PF /Relative standard deviation (RSD). The limits of normal, are defined as the 5th and 95th percentile limits (z-score between -1.645 and 1.645), respectively.

METHODS

Patients underwent a clinical examination with full spine standing radiographs and EFPT. The results were compared between patients with thoracic and thoracolumbar/lumbar (TL/L) main curves, and overall compared with a background population. Results were expressed with z-scores derived from height and arm span normative data.

RESULTS

Of 77 included patients, 76 (99%) were females with a mean age of 54.6±2.5 years. The mean follow-up time was 40.8±2.8 years. Forty-four patients had thoracic main curves, and 33 had TL/L main curves. We found no pulmonary impairment based on z-scores in the total cohort or between groups, with only patients who were current or previous smokers, having z-scores below the normal limits Patients with main thoracic curves displayed significantly lower PF on mean absolute values and mean z-scores on FEV1, FVC, FEV1/FVC ratio, VC, TLC, and DLco compared with main TL/L curves. Patients with thoracic curves had significantly larger Cobb angles at follow-up; 52±17° compared with 40±22° (p-value <.05) in the TL/L group. We found no linear association between thoracic Cobb angle and degree of pulmonary impairment assessed with DLco, TLC, and FVC. Comparison of pulmonary z-scores based on arm span data, differed significantly on FVC and TLC, with the arm span measurements showing lower mean z-scores (p-value <.05).

CONCLUSIONS

Using EPFT, no pulmonary impairment could be demonstrated compared to the age-matched population 40 years after a diagnosis of IS. However, patients with thoracic curves had decreased PF compared to patients with TL/L curves although within the normal range. Thus, when treated as current guidelines suggest, patients with idiopathic scoliosis can expect the same long-term pulmonary function as the general population.

Changes in Diaphragm Intrusion and Thoracic Dimensions After Posterior Spinal Fusion in Patients With Neuromuscular Scoliosis

BACKGROUND

Cerebral palsy (CP) can cause scoliosis with large thoracolumbar or lumbar curves. Such curves may impair pulmonary function by causing the abdomen and diaphragm to encroach on the thorax. Our purpose was to investigate changes in diaphragm position and other thoracic radiographic measurements at 2 years after posterior spinal fusion (PSF).

METHODS

Retrospective review of data from 56 pediatric patients (Gross Motor Function Classification System >3) who underwent PSF for CP-related (neuromuscular) scoliosis at one US academic hospital from 2010 to 2018. In this study, we used radiographs taken preoperatively and 2 years after PSF to measure lung volume, diaphragm intrusion index (DII), diaphragm vertebral level (DVL), space available for the lung (SAL), and T1-S1 height.

RESULTS

Lung volume had increased by a mean 902 cm3 (range, -735 to 2697 cm3) at 2-year follow-up. DII improved from a mean (and SD) of 61%±12% to 71%±11% on the left side and 58%±14% to 68%±11% on the right (P<0.001). DVL increased caudally by a mean 1.2 vertebral levels bilaterally, with a mean postoperative position between T8 and T9. Lung space became more symmetrical as the SAL increased from 0.76 to 0.91 (P<0.001). T1-S1 height increased by a mean 7.5±4.3 cm.

CONCLUSIONS

These findings suggest a new way to understand changes in thoracic volume and redistribution of thoracic and lumbar balance when correcting the collapsing spinal deformity in CP. A more caudal postoperative diaphragm position with less diaphragm intrusion into the thorax may reflect an improved length-tension configuration, which could in turn produce greater diaphragmatic strength and endurance.

LEVEL OF EVIDENCE

Level III.

Benefit-risks analysis of thoracoplasty in adolescent idiopathic scoliosis treated by sublaminar bands

INTRODUCTION

Cosmetic concerns are one of the main complaints of patients with adolescent idiopathic scoliosis (AIS). Several studies have shown a significant improvement in self-image scores after thoracoplasty. However, the effects of thoracoplasty on pulmonary function and clinical outcomes remain debated. The objective was to analyze the benefits and risks of thoracoplasty during AIS surgery using a hybrid construct with sublaminar bands.

MATERIAL AND METHODS

In this monocentric prospective cohort study, 68 patients with thoracic AIS were consecutively included between 2016 and 2017. All patients had low-dose 3D radiographs. Surgical correction was performed via the posterior approach, using the posteromedial translation technique with a hybrid construct (thoracic sublaminar band and lumbar pedicle screws). A thoracoplasty was proposed in cases of severe rib hump (more than 3cm). Pulmonary function was assessed by pulmonary function tests (PFT) with forced vital capacity, forced expiratory volume in 1 second and total lung capacity). Radiographic parameters and PFT were compared between patients who had or had not had a thoracoplasty preoperatively and 2 years postoperatively. The SRS-22 score was collected at follow-up.

RESULTS

The average age was 15±3 years. Nineteen patients (27%) had a thoracoplasty. The demographic, radiographic and respiratory data of the 2 groups were comparable preoperatively. The correction was similar between the groups on sagittal and coronal views. At 2 years, the PFTs were comparable to those performed preoperatively and no difference was found between the groups. None of the 12 patients who had a pleural effusion had it drained. The total SRS-22 score and the cosmetic subscore were higher in the thoracoplasty group (p<0.03).

DISCUSSION

The association of a thoracoplasty with AIS surgery improves the self-image of patients without altering the PFTs at 2 years postoperatively. Given the low morbidity of thoracoplasty, it seems reasonable to offer it to patients with severe rib hump and high cosmetic demands.

LEVEL OF EVIDENCE

III.

Hypermobility Among Adolescents and the Association With Spinal Deformities: A Large Cross-Sectional Study

INTRODUCTION

Adolescent idiopathic scoliosis and Scheuermann kyphosis are common spinal deformities (SD) among adolescents. The potential link between hypermobility and SD is a topic of debate. We aimed to investigate the prevalence of hypermobility and its association with SD.

METHODS

A cross-sectional analysis of records of 17-year-old subjects who were recruited into mandatory military service was conducted. Study population comprised 1,220,073 subjects. Prevalence rates were calculated for hypermobility and different categories of SD by severity, studying the strength of the association between hypermobility and SD.

RESULTS

Of 1,220,073 subjects, 0.0111% exhibited hypermobility. Spinal deformities were identified in 10.5% of subjects. Specifically, 7.9% had mild SD, 2.4% had moderate SD, and 0.1% had severe SD. The overall association between hypermobility and SD showed an odds ratio of 2.31 (P < 0.001). Subgroup analyses revealed ORs of 1.226 (P = 0.041) for mild deformities, 5.783 (P < 0.001) for moderate deformities, and 4.01 (P = 0.002) for severe deformities. The association was stronger for moderate and severe SD.

CONCLUSIONS

This study establishes a notable association between hypermobility and SD among adolescents. The findings highlight the importance of understanding this relationship, which could contribute to advancements in comprehending SD development. Additional research is warranted to expand upon these findings.

Novel Surface Topographic Assessment of Lung Volume and Pulmonary Function Tests in Idiopathic Scoliosis: A Preliminary Study

OBJECTIVE

Severe spinal deformity results in restrictive pulmonary disease from thoracic distortions and lung-volume limitations. Though spirometry and body plethysmography are widely accepted tests for pulmonary function tests (PFTs), they are time-consuming and require patient compliance. This study investigates whether surface topographic [surface topography (ST)] measurements of body volume difference (BVD) and torso volume difference between maximum inhale and exhale correlate to values determined on PFTs.

METHODS

This study included patients with idiopathic scoliosis and thoracic/thoracolumbar curves ≥40 degrees. Patients received ST scans, clinical examinations, and EOS biplanar radiographs on the same day. PFTs were performed within 3 months of ST/radiographic analysis. Univariate linear regression analysis was used to examine relationships between BVD, PFT values, and mean curves.

RESULTS

Sixteen patients (14.6 ± 2.2 y, 69% females) with idiopathic scoliosis and mean thoracic/thoracolumbar curves of 62 degrees ± 15˚ degrees (45 degrees to 93 degrees) were assessed. BVD displayed statistically high-positive positive correlations with forced vital capacity ( R = 0.863, P < 0.0001), forced expiratory volume in 1 second ( R = 0.870, P < 0.001), vital capacity ( R = 0.802, P < 0.0001), and TLC ( R = 0.831, P < 0.0001. Torso volume difference showed similarly high positive correlations to forced vital capacity, forced expiratory volume in 1 second, vital capacity, and TLC, but not residual volume. No correlations emerged between the mean thoracic/thoracolumbar curve and BVD or PFT values.

CONCLUSION

This study strongly endorses further investigation into ST scanning as an alternative to traditional PFTs for assessing pulmonary volumes. The noncontact and noninvasive nature of ST scanning presents a valuable alternative method for analyzing thoracic volume, particularly beneficial for patients unable to cooperate with standard PFTs.

LEVEL OF EVIDENCE

Level II-prognostic.

Application of the Six-Minute Walk Test in Assessment of the Cardiopulmonary Function of Children With Idiopathic Scoliosis

STUDY DESIGN

A retrospective observational study.

OBJECTIVE

To assess whether the six-minute walk test (6MWT) can predict cardiopulmonary function in children with idiopathic scoliosis (IS) as an alternative to the cardiopulmonary exercise test (CPET).

SUMMARY OF BACKGROUND DATA

Cardiopulmonary functional impairment in the setting of IS is a common health problem. A simple and convenient assessment method is needed.

MATERIALS AND METHODS

We recruited 65 children (eight male, 57 female) aged 10.70 to 14.84 years old with IS. Radiographic characteristics of the cohort were measured, including Risser's sign and Cobb angle. We measured cardiopulmonary exercise tolerance using both the 6MWT and CPET and their corresponding indicators, including six-minute walking distance (6MWD) and peak oxygen uptake (peak VO 2 ), respectively. Pearson correlation analysis was used to determine the relationship between 6MWT indicators and IS parameters. Linear regression models were used to explore the relationship between 6MWT and CPET response indicators.

RESULTS

Over a third of the cohort (35.4%) had a Risser's sign grade of 0, with 21.5% in grade 2 and 3, respectively. The cohort's mean Cobb angle was 26.02°. 6MWD was significantly positively correlated with Risser's sign ( R =0.258; P =0.038) and change in respiratory rate positively correlated with vertebral rotation ( R =0.264; P =0.034). 6MWD positively correlated with peak VO 2 , peak VO 2 /heart rate (HR), and metabolic equivalents, and negatively correlated with the ventilation equivalent of the carbon dioxide slope (VE/VCO 2 slope) ( P <0.05). These four CPET indicators were found to be predicted from 6MWD in the linear regression model ( P <0.05).

CONCLUSIONS

CPET response indicators, especially peak VO 2 , can be predicted using 6MWD, among other factors. The 6MWT can therefore be used to rapidly and efficiently predict the cardiorespiratory tolerance of children with IS.

LEVEL OF EVIDENCE

3.

Respiratory function and respiratory muscle strength in adolescent idiopathic scoliosis

PURPOSE

It was aimed to analyze the relationship of the respiratory functions, respiratory muscle strength, magnitude of the curvature, angle of trunk rotation (ATR) and brace-wearing duration in patients with adolescent idiopathic scoliosis (AIS).

METHODS

Sixty patients with AIS (43 females), with maximum Cobb angles between 20° and 66° were included in the study. ATR values were measured with a scoliometer. Respiratory function parameters (forced vital capacity [FVC], forced expiratory volume in one second [FEV1], FEV1/FVC ratio, peak expiratory flow [PEF]) and respiratory muscle strengths (maximum inspiratory pressure [MIP] and maximum expiratory pressure [MEP]) were measured by combined spirometry.

RESULTS

There was a negative significant correlation between maximum Cobb angle and ATR with respiratory function parameters except for PEF and FEV1/FVC (r = -0.258-0.441; p = <0.001-0.047). There was a moderate negative correlation between ATR with MIP (cmH2O) (r = -0.377; p = 0.003) and MEP (cmH2O) (r = -0.362; p = 0.005). On the other hand, no correlation was found between brace-wearing duration with respiratory functions, maximum Cobb angle and brace-wearing duration with respiratory muscle results.

CONCLUSION

The results of this study showed that, respiratory functions were normal or mildly affected, and respiratory muscle strengths were weak in AIS. Increased Cobb angle and ATR negatively affected respiratory function; increased ATR was associated with decreased inspiratory and expiratory muscle strength. It is extremely important to carefully evaluate the respiratory system and to know the variables that affect respiratory functions and respiratory muscle strength in achieving optimum recovery in the holistic treatment of individuals with scoliosis.

The Impact of Anterior Vertebral Body Tethering on Pulmonary Function

STUDY DESIGN

Retrospective, single-center study.

OBJECTIVE

To examine pulmonary function tests (PFTs) in patients undergoing anterior vertebral body tethering (AVBT).

SUMMARY OF BACKGROUND DATA

The effect of AVBT on pulmonary status remains unclear.

MATERIALS AND METHODS

The authors examined preoperative and postoperative PFTs following AVBT in a retrospective, single-center cohort of patients. Outcomes were compared using percent predicted values as continuous and categorical variables (using 10% change as significant) and divided into categorical values based on the American Thoracic Society standards.

RESULTS

Fifty-eight patients with adolescent idiopathic scoliosis were included, with a mean age of 12.5±1.4 years and a follow-up of 4.2±1.1 years. The mean thoracic curve was 47°±9°, which improved to 21°±12°. At baseline, the mean forced expiratory volume in one second (FEV1%) and forced vital capacity (FVC%) values were 79% and 82%, respectively. Four patients had normal FEV1% (≥100%), 67% had mild restrictive disease (70%-99%) and the rest had worse FEV1%. Mean FEV1 improved from 2.2 to 2.6 L ( P <0.05) and FVC improved from 2.5 to 3.0 L ( P <0.05); however, % predicted values remained unchanged (FEV1%: 79%-80%; FVC%: 82-80%, P >0.05) with mean postoperative PFTs at 37±12 months postoperative. The use of miniopen thoracotomy was not associated with worsening PFTs, but extension of the lowest instrumented vertebra below T12 was correlated with decreasing FEV1% in the bivariate analysis ( P <0.05). Patients with worse preoperative FVC% (80±13% vs. 90±11%, P =0.03) and FEV1% (77±17% vs. 87±12%, P =0.06) also had a greater likelihood of declining postoperative FEV1%.

CONCLUSION

Pulmonary function in most patients undergoing AVBT remained stable (76%) or improved (14%); however, a subset may worsen (10%). Further studies are needed to identify the risk factors for this group, but worse preoperative PFTs and extension below T12 may be risk factors for worsening pulmonary function.

Impairments in pulmonary functions in paediatric spinal tuberculosis: a cross-sectional study

PURPOSE

This study aimed to investigate the impact of vertebral column destruction and kyphotic deformity due to spinal tuberculosis on pulmonary functions in paediatric patients.

METHODS

A cross-sectional study was conducted, involving 30 patients diagnosed with healed spinal tuberculosis, aged 7-18 years. Detailed radiographic measurements, including the level of involvement, kyphosis angle, Spinal Deformity Index (SDI), and drug-resistance status, were compared with various pulmonary function parameters.

RESULTS

The mean age of the study group was 12.8 ± 2.7 years (range 7-17 years), consisting of 11 males and 19 females. Fourteen patients were managed conservatively and 16 were managed operatively. The mean SDI was 5.2 ± 4.7. The mean kyphotic angle was 31.3° ± 25.3. The average number of involved vertebrae was 2.6 ± 1.5. Pulmonary functions were classified as restrictive in 24 patients, normal in 4 patients, obstructive in 1 patient, and mixed in 1 patient. Multidrug-resistant tuberculosis (MDR-TB) was detected in 5 (16.7%) patients, while the remaining 25 (83.3%) patients were sensitive to conventional antitubercular drugs. The correlation coefficients between the percentage reduction in forced vital capacity (FVC) and kyphosis angle, SDI, and number of vertebrae were 0.4 (p = 0.026), 0.4 (p = 0.028), and 0.19 (p = 0.295), respectively. The mean percentage reduction in FVC and total lung capacity (TLC) were 35.8 ± 15.7 and 6.2 ± 2.3, respectively. No significant association was observed between pulmonary functions and drug sensitivity status (p = 0.074).

CONCLUSIONS

Paediatric spinal tuberculosis can lead to thoracic insufficiency due to progressive destruction and shortening of the spinal column, spinal growth inhibition, and kyphotic deformity. Management of these cases should focus on promoting normal lung development while ensuring disease resolution and deformity correction. Further research should explore growth conserving or growth guiding systems to address or prevent growth retardation and simultaneously provide spinal stabilization.

Impact of pleural effusion at an early period after posterior spinal fusion for adolescent idiopathic scoliosis on future pulmonary function and lung volume

Background

Posterior spinal fusion (PSF) for adolescent idiopathic scoliosis (AIS) has a potential risk for postoperative pleural effusion. Although pleural effusion at an early period after PSF for AIS occurs with a relatively high frequency and occasionally requires some treatments, the impact of postoperative pleural effusion on future pulmonary function or lung volume (LV) has not been clarified to date. The aim of this study was to evaluate the effect of pleural effusion after PSF for AIS on the postoperative pulmonary function and LV.

Methods

A total of 114 consecutive patients who underwent PSF for AIS followed up greater than 2 years at our institute were retrospectively reviewed. We evaluated postoperative pleural effusion by computed tomography (CT) at the 1-week follow-up and divided patients into the pleural effusion (PF) and non-pleural effusion (NP) groups. We investigated spirometry parameters recorded for testing included vital capacity (VC), forced expiratory volume in the first second (FEV1), %VC, and FEV1% and measured the LV using CT images and a workstation at baseline and 2 years after surgery.

Results

A total of 87 (76.3%) patients with postoperative pleural effusion were identified, but all patients were asymptomatic and did not require additional treatment for postoperative pleural effusion. All pulmonary function parameters at the 2-year follow-up exhibited no significant differences between the two groups. Although preoperative left LV (1.21±0.30 L vs. 1.36±0.34 L; p=.022) and total LV (2.68±0.62 L vs. 2.99±0.73 L; p=.031) were significantly lower in the PF group than in the NP group, all postoperative LV parameters were similar between the two groups.

Conclusions

Pleural effusion at an early period after PSF for AIS was a postoperative occurrence without an impact on future pulmonary function and LV.

Improvement of Pulmonary Function and Reconstructed 3-Dimensional Lung Volume After Halo-Pelvic Traction Combined With Posterior Correction for Severe Rigid Spinal Scoliosis: A Multicenter Study

BACKGROUND AND OBJECTIVES

Severe rigid spinal scoliosis (SRSS) leads to severe restrictive ventilation dysfunction. Currently, the reports about the influence of preoperative halo-pelvic traction (HPT) combined with correction surgery on pulmonary function in patients with SRSS were relatively few. This study aims to investigate (1) the influence of preoperative HPT on lung volume and pulmonary function, (2) the further influence of the following correction surgery on lung volume and pulmonary function, and (3) the relationship among deformity correction, pulmonary function test outcomes, and computed tomography-based lung volume.

METHODS

A total of 135 patients with SRSS who underwent preoperative HPT and followed low-grade osteotomy correction surgery were reviewed. Spinal parameters, including proximal thoracic curve, main thoracic curve (MTC), lumbar curve, coronal balance, thoracic kyphosis, lumbar lordosis, sagittal vertical axis, pulmonary function test outcomes (forced vital capacity [FVC], the percentage of predicted forced vital capacity [FVC%], forced expiratory volume in 1 second [FEV1], total lung capacity [TLC]), and lung volume (Vin), were analyzed before, after HPT and at the final follow-up, respectively.

RESULTS

The mean FVC, FVC%, FEV1, and TLC increased from 1.67 L, 51.13%, 1.47 L, and 2.37 L to 1.95 L, 64.35%, 1.75 L, and 2.78 L, respectively, after HPT and further improved to 2.22 L, 72.14%, 1.95 L, and 3.15 L, respectively, at the final follow-up. The mean Vin increased from 1.98 L to 2.42 L after traction and further increased to 2.76 L at the final follow-up. The variation of MTC was correlated with the improvement of FVC (r = 0.429, P = .026), FVC% (r = 0.401, P = .038), FEV1 (r = 0.340, P = .043), and TLC (r = 0.421, P = .029) and the variation of Vin (r = 0.425, P = .015) before HPT and after surgery.

CONCLUSION

Preoperative HPT can improve preoperative pulmonary function and enhance the preoperative lung volume. There were significant correlations among the variations of MTC, pulmonary function indexes, and lung volume before HPT and after surgery in patients with SRSS.

Patient and surgical predictors of 3D correction in posterior spinal fusion: a systematic review

BACKGROUND

Restoration of three-dimensional (3D) alignment is critical in correcting patients with adolescent idiopathic scoliosis using posterior spinal fusion (PSF). However, current studies mostly rely on 2D radiographs, resulting in inaccurate assessment of surgical correction and underlying predictive factors. While 3D reconstruction of biplanar radiographs is a reliable and accurate tool for quantifying spinal deformity, no study has reviewed the current literature on its use in evaluating surgical prognosis.

PURPOSE

To summarize the current evidence on patient and surgical factors affecting sagittal alignment and curve correction after PSF based on 3D parameters derived from reconstruction of biplanar radiographs.

METHODS

A comprehensive search was conducted by three independent investigators on Medline, PubMed, Web of Science, and Cochrane Library to obtain all published information on predictors of postoperative alignment and correction after PSF. Search items included "adolescent idiopathic scoliosis," "stereoradiography," "three-dimensional," "surgical," and "correction." The inclusion and exclusion criteria were carefully defined to include clinical studies. Risk of bias was assessed with the Quality in Prognostic Studies tool, and level of evidence for each predictor was rated with the Grading of Recommendations, Assessment, Development, and Evaluations approach. 989 publications were identified, with 444 unique articles subjected to full-text screening. Ultimately, 41 articles were included.

RESULTS

Strong predictors of better curve correction included preoperative normokyphosis (TK > 15°), a corresponding rod contour, intraoperative vertebral rotation and translation, and upper and lower instrumented vertebrae selected based on sagittal and axial inflection points. For example, for Lenke 1 patients with junctional vertebrae above L1, fusion to NV-1 (1 level above the neutral vertebra) achieved optimal curve correction while preserving motion segments. Pre-op coronal Cobb angle and axial rotation, distal junctional kyphosis, pelvic incidence, sacral slope, and type of instrument were identified as predictors with moderate evidence. For Lenke 1C patients, > 50% LIV rotation was found to increase spontaneous lumbar curve correction. Pre-op thoracolumbar apical translation and lumbar lordosis, Ponte osteotomies, and rod material were found to be predictors with low evidence.

CONCLUSIONS

Rod contouring and UIV/LIV selection should be based on preoperative 3D TK in order to achieve normal postoperative alignment. Specifically, Lenke 1 patients with high-lying rotations should be fused distally at NV-1, while hypokyphotic patients with large lumbar curves and truncal shift should be fused at NV to improve lumbar alignment. Lenke 1C curves should be corrected using > 50% LIV rotation counterclockwise to the lumbar rotation. Further investigation should compare surgical correction between pedicle-screw and hybrid constructs using matched cohorts. DJK and overbending rods are potential predictors of postoperative alignment.

Effects of inspiratory muscle training on respiratory muscle strength, respiratory function and functional capacity in adolescents with idiopathic scoliosis : A randomized, controlled trial

BACKGROUND

Adolescent Idiopathic Scoliosis (AIS) may impair respiratory dynamics and affect the performance of inspiratory and expiratory muscles. The benefit of inspiratory muscle training (IMT) is not well investigated in AIS. We aimed to investigate the effects of IMT on respiratory muscle strength, respiratory function and functional capacity in adolescents with mild to moderate AIS.

METHODS

Thirty-six adolescents were randomized into control or IMT groups. Forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1) and peak expiratory flow (PEF) were measured by spirometry; respiratory muscle strength by maximum inspiratory pressure (MIP) and maximum expiratory pressure (MEP); and functional capacity by 6-min walk test (6MWT) before and after the 8-week-long home-based exercise program. Both groups received conventional exercise program including diaphragmatic breathing exercises, resistive local expansion exercise on the collapsed areas in concave sides of scoliosis, spinal stabilization, strengthening of interscapular muscles and stretching exercises. IMT group also trained with Threshold IMT device for 15 minutes, twice a day for 8 weeks at the intensity of 30% of initial MIP value in addition to conventional exercise program.

RESULTS

FEV1, PEF, MIP, MEP and 6MWT distance significantly improved in both groups. IMT group also showed significant improvement in FVC. The increases in FVC, MIP, MEP and 6MWT distance of IMT group were significantly higher compared to control group.

CONCLUSION

IMT is found to be beneficial for patients with AIS for achieving further improvements in respiratory function, respiratory muscle strength and functional capacity compared to conventional exercise program alone.

What Are the Effects of Posterior Corrective Surgery, With or Without Thoracoplasty, on Pulmonary Function in Adolescent Idiopathic Scoliosis? A Systematic Review and Meta-analysis

STUDY DESIGN

Systematic review and meta-analysis.

OBJECTIVES

This study's objective is to provide a critical review of the current literature regarding the changes in pulmonary function (PF) in Adolescent idiopathic scoliosis (AIS) patients who have undergone posterior spinal fusion and instrumentation (PSF), with and without thoracoplasty (TP).

METHODS

A comprehensive search was performed using the following databases: EMBASE, PubMed, EBSCOhost (CINAHL and Medline) and OpenGrey. Our focus was on studies that compared pre-and postoperative percent-predicted values of forced vital capacity (%FVC) or forced expiratory volume in 1 second (%FEV1) in AIS patients who had undergone PSF, with and without TP, with a minimum 2-year follow-up. The risk of bias for included studies was assessed using the ROBINS-I ("Risk Of Bias In Non-randomised Studies - of Interventions") tool. Mean change scores were depicted using forest plots.

RESULTS

Fifteen studies met our inclusion criteria. The results of our analysis suggest that PSF with TP caused a significant deterioration of %FVC in individuals with moderate AIS, with no significant effect on %FEV1. It also showed a minor improvement of FEV1% in individuals with moderate AIS after PSF only, but no significant change in %FVC.

CONCLUSIONS

PSF with TP caused a significant deterioration of % FVC while PSF alone caused a minor improvement of FEV1% in individuals with moderate AIS with a minimum 2-year follow-up.

Assessment of Regional Functional Effects of Surgical Treatment in Thoracic Insufficiency Syndrome via Dynamic Magnetic Resonance Imaging

BACKGROUND

Quantitative regional assessment of thoracic function would enable clinicians to better understand the regional effects of therapy and the degree of deviation from normality in patients with thoracic insufficiency syndrome (TIS). The purpose of this study was to determine the regional functional effects of surgical treatment in TIS via quantitative dynamic magnetic resonance imaging (MRI) in comparison with healthy children.

METHODS

Volumetric parameters were derived via 129 dynamic MRI scans from 51 normal children (November 2017 to March 2019) and 39 patients with TIS (preoperatively and postoperatively, July 2009 to May 2018) for the left and right lungs, the left and right hemi-diaphragms, and the left and right hemi-chest walls during tidal breathing. Paired t testing was performed to compare the parameters from patients with TIS preoperatively and postoperatively. Mahalanobis distances between parameters of patients with TIS and age-matched normal children were assessed to evaluate the closeness of patient lung function to normality. Linear regression functions were utilized to estimate volume deviations of patients with TIS from normality, taking into account the growth of the subjects.

RESULTS

The mean Mahalanobis distances for the right hemi-diaphragm tidal volume (RDtv) were -1.32 ± 1.04 preoperatively and -0.05 ± 1.11 postoperatively (p = 0.001). Similarly, the mean Mahalanobis distances for the right lung tidal volume (RLtv) were -1.12 ± 1.04 preoperatively and -0.10 ± 1.26 postoperatively (p = 0.01). The mean Mahalanobis distances for the ratio of bilateral hemi-diaphragm tidal volume to bilateral lung tidal volume (BDtv/BLtv) were -1.68 ± 1.21 preoperatively and -0.04 ± 1.10 postoperatively (p = 0.003). Mahalanobis distances decreased after treatment, suggesting reduced deviations from normality. Regression results showed that all volumes and tidal volumes significantly increased after treatment (p < 0.001), and the tidal volume increases were significantly greater than those expected from normal growth for RDtv, RLtv, BDtv, and BLtv (p < 0.05).

CONCLUSIONS

Postoperative tidal volumes of bilateral lungs and bilateral hemi-diaphragms of patients with TIS came closer to those of normal children, indicating positive treatment effects from the surgical procedure. Quantitative dynamic MRI facilitates the assessment of regional effects of a surgical procedure to treat TIS.

LEVEL OF EVIDENCE

Diagnostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Pulmonary Parameters in Adolescents with Severe Thoracic Idiopathic Scoliosis: Comparison Girls versus Boys

The study compared pulmonary parameters, registered at the preoperative examination, in adolescent boys versus girls, both with severe thoracic idiopathic scoliosis. Thirty consecutive boys and 30 consecutive girls with Lenke 1 or 3 type, in the age range 14−18 years, with a Cobb angle of >50° and Risser sign ≥ 3 were enrolled. Corrected body height was used to calculate pulmonary parameters according to the Global Lung Function (GLI 2012) reference values. Significantly higher values of the calculated predicted pulmonary parameters and the upper and lower limit of normal (ULN and LLN), as well as significantly higher absolute values of forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1), were observed in boys than girls; however, the registered FVC and FEV1, expressed as percentages of the predicted values, tended to be lower in boys. The FEV1 z-score difference between boys and girls may suggest a need for more intensive preoperative pulmonary rehabilitation in boys.

Systematic review of the association between isolated musculoskeletal hypermobility and adolescent idiopathic scoliosis

INTRODUCTION

Adolescent idiopathic scoliosis (AIS) affects 1-3% of the population, but its pathogenesis remains unclear. The coexistence of musculoskeletal hypermobility and scoliosis in many inherited syndromes raises the possibility that isolated musculoskeletal hypermobility may contribute to AIS development or progression.

METHODS

We performed a systematic review of the evidence for a relationship between isolated musculoskeletal hypermobility and AIS. A meta-analysis was planned, but if not possible, a narrative evidence synthesis was planned.

RESULTS

Nineteen studies met eligibility criteria for inclusion. One study was excluded due to insufficient quality. Substantial heterogeneity in study design and methodology negated meta-analysis, so a narrative review was performed. Of the 18 studies included, seven suggested a positive association and eight found no association. Three reported the prevalence of musculoskeletal hypermobility in individuals with AIS. Overall, there was no convincing population-based evidence for an association between musculoskeletal hypermobility and AIS, with only two case-control studies by the same authors presenting compelling evidence for an association. Although populations at extremes of hypermobility had a high prevalence of spinal curvature, these studies were at high risk of confounding. Wide variation in methods of measuring musculoskeletal hypermobility and the challenge of assessing AIS in population-based studies hinder study comparison.

CONCLUSIONS

There is a paucity of high-quality evidence examining the association between isolated musculoskeletal hypermobility and AIS. Large-scale prospective studies with adequate adjustment for potential confounding factors could clarify the relationship between musculoskeletal hypermobility and AIS to elucidate its role in the pathogenesis of AIS.

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.

Pulmonary Recovery Following Corrective Surgery in Adult Patients With Severe Scoliosis: A Minimum of Five-Year Follow-Up

Background

Halo gravity traction (HGT) has been reported to be a safe and effective adjunctive method for the management of scoliosis. However, the direct effects of HGT on the lung recovery of adult patients with scoliosis remain obscure.

Objective

To investigate changes in lung volume and pulmonary function in adult patients with severe scoliosis who underwent posterior spinal fusion concomitant with preoperative halo gravity traction.

Methods

A total of 47 patients with a minimum 5-year follow-up who underwent posterior spinal instrumentation and fusion using preoperative halo–gravity traction were analyzed. Pulmonary function tests and three-dimensional CT were performed to evaluate changes in lung function and lung volume, respectively.

Results

There was significant change in the Cobb angle of the major curve after halo gravity traction (P < 0.0001). Significant improvement in both Cobb angle (P < 0.0001) and thoracic kyphosis (P = 0.034) after corrective surgery was observed. Pulmonary function did not change significantly during traction. However, a significant decline in absolute and percent-predicted pulmonary function values was noted following surgery. The average change in lung volume did not show statistical differences during traction. At 5-year postoperative follow-up, the mean values revealed a significant increase in total lung volume (P < 0.0001) and concave lung volume (P < 0.0001) with surgical correction, but no statistically significant change in lung volume on the convex side (P = 0.57). Postoperative pulmonary complications occurred in nine cases with lower preoperative pulmonary function, indicating the importance of performing spirometry before corrective surgery.

Conclusions

We found that halo gravity traction prior to corrective surgery was less useful in improving pulmonary function in adult patients with severe scoliosis. However, these patients were expected to have increased lung volume after correction of the deformity.

Ultrasound Shear Wave Elastography of the Intervertebral Disc and Idiopathic Scoliosis: A Systematic Review

Ultrasound shear wave elastography is a radiation-free and low-cost technique for evaluating the mechanical properties of different tissues. This study systematically reviewed all relevant literature on shear wave elastography of the intervertebral disc. The purpose was twofold: first, to determine the validity of the elastography method, that is, the correlation between elastographically measured shear wave speed and disc mechanical properties, and inter-/intra-operator reliability; and second, to explore if disc elastography is potentially useful in identifying children at risk for idiopathic scoliosis. This systematic review was performed according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) guidelines. A comprehensive search was performed in PubMed and Embase, and study quality was assessed using the AXIS (Appraisal Tool for Cross-sectional Studies) critical appraisal instrument. Seven articles were included. Three animal ex vivo studies reported moderate-to-good correlations between shear wave speed and disc mechanical properties (r = 0.45-0.81). Three studies reported high intra-operator repeatability (intra-class correlation coefficient [ICC] 0.94-0.99) and inter-operator reproducibility (ICC 0.97-0.98). Four clinical studies measured shear wave speed in asymptomatic children. Two studies reported significantly higher shear wave speeds in scoliosis patients compared with healthy controls, measured in discs both inside and outside the scoliotic curve. In conclusion, shear wave elastography appears reliable in assessing intervertebral disc mechanical characteristics. Despite its promising capabilities to distinguish patients with asymptomatic from those with pathological discs, the exact correlation between disc mechanical properties and shear wave speed remains unclear.

Factors affecting postoperative pulmonary function deterioration in adolescent idiopathic scoliosis: A prospective study using 3-dimensional image reconstruction by biplanar stereoradiography

This study aimed both to evaluate rib cage parameters in patients with adolescent idiopathic scoliosis (AIS) by three-dimensional (3D) image reconstruction using biplanar stereoradiography (EOS) (EOS Imaging, Paris, France) and identify factors associated with postoperative pulmonary function deterioration (PFD). A total of 67 patients with Lenke type 1 or 2 AIS (59 females and 8 males; mean age, 14.4 years) undergoing posterior corrective fusion with a rod rotation maneuver based on segmental pedicle screw fixation were recruited. 3D images and pulmonary function test results were analyzed preoperatively and at 2 years postoperatively. The following parameters were measured: maximum thickness, maximum width, thoracic index, rib hump, rib cage volume (RCV), spinal penetration index (SPI), endothoracic hump ratio (EHR), vertebra-sternum angle (VSA), rib-vertebra angle difference, vertebral lateral decentering (VLD), forced vital capacity (FVC), and percent predicted FVC (%FVC). PFD was defined as a postoperative %FVC decline of 5% or greater. Patients were divided into two groups, namely PFD and non-PFD. FVC increased from 2.62 L to 2.73 L, while %FVC decreased from 88.7% to 82.7%. The maximum width diminished postoperatively in the PFD group. Patients in the PFD group exhibited a significantly smaller increase in RCV and VLD as well as a significantly smaller decrease in SPI, EHR, and VSA than those in the non-PFD group. The rib cage parameters quantified on 3D images reconstructed using EOS are useful in identifying factors affecting PFD in patients with AIS.

Influences of Thoracic Spinal Deformity on Exercise Performance and Pulmonary Function: A Prospective Study of 168 Patients with Adolescent Idiopathic Scoliosis

STUDY DESIGN

A prospective study.

OBJECTIVE

The aim of this study was to investigate the factors associated with cardiopulmonary exercise testing (CPET) measurements in patients with adolescent idiopathic scoliosis (AIS).

SUMMARY OF BACKGROUND DATA

Patients with AIS display restrictive pulmonary dysfunction on pulmonary function testing (PFT). It remains unknown whether thoracic spinal deformity affects exercise performance.

METHODS

One hundred and sixty-eight patients with AIS from January 2014 to December 2019 were included. They underwent preoperative spinal radiological assessment, PFT, and CPET. The effects of the thoracic curve magnitude, body mass index, physical activity level and history of bracing on pulmonary function and exercise performance were analyzed. The Student t test and two-tailed Pearson test were used in data analysis.

RESULTS

We found significantly reduced forced expiratory volume in 1second (FEV1) in patients with a larger magnitude of the proximal thoracic curve (P < 0.001) and the main thoracic curve (P < 0.001). There was a negative correlation between forced vital capacity (FVC) and the magnitude of the main thoracic curve (P < 0.001) and thoracic hypokyphosis (P < 0.001). In CPET, exercise capacity indicators such as the work rate, peak oxygen intake, and heart rate were not affected by the thoracic curve magnitude. Patients with moderate or severe pulmonary dysfunction had decreased tidal volume (P = 0.01) and ventilatory reserve (P < 0.001), as well as increased respiratory frequency at maximal exercise (P = 0.01). Patients with a moderate or high physical activity level had better exercise capacity, which was reflected by a higher work rate (P = 0.009) and oxygen intake (P < 0.001).

CONCLUSION

There was no significant correlation between radiographic parameters and exercise capacity indicators. When the thoracic curve increased, patients had restrictive ventilatory dysfunction, which led to a tachypneic breathing pattern and reduction of ventilatory reserve during exercise. A physiological change of improved peak oxygen intake was demonstrated in patients with a moderate or high physical activity level.Level of Evidence: 3.

Evaluation of the Parameters Affecting Respiratory Functions at Adolescent Idiopathic Scoliosis Patients

STUDY DESIGN

This was a retrospective observational study.

OBJECTIVE

The objective of the study was to evaluate the spinal and extraspinal factors responsible for pulmonary dysfunction in adolescent idiopathic scoliosis patients.

SUMMARY OF BACKGROUND DATA

Development of thoracic deformity due to scoliosis results with the restrictive ventilatory pattern and the reduced pulmonary function. To prevent pulmonary function deterioration, it is imperative to understand which factors are causing the restrictive lung disease in adolescent idiopathic scoliosis patients.

MATERIALS AND METHODS

An online database search was conducted in a hospital computerized archive between 2008 and 2018 years. Cobb angle of >30 degrees, Lenke type 1 and 2 patients treated in a single spine unit were included. Coronal and sagittal Cobb angle, bending correction rate for evaluation of flexibility, Risser score, apical vertebra rotation (AVR), and pulmonary function test of patients were obtained.

RESULTS

There was a moderate negative correlation between forced expiratory volume in the first second, forced vital capacity, and AVR. There was no correlation between forced expiratory volume in the first second and forced vital capacity with age, sex, Cobb angle, Risser score, kyphosis, and bending correction rate.

CONCLUSIONS

When considering the results of the current study and the other studies in the literature there is not any strong correlation between the features of scoliotic curvature and respiratory functions. In the current study, 52 (72.22%) of 72 patients with moderate to severe scoliosis had mild to severe respiratory dysfunction. Considering the age-related physiological respiratory loss, to evaluate the necessity of surgical treatment in patients with moderate and severe scoliosis, especially in patients with high AVR, the respiratory functions of the patient should also be evaluated.

LEVEL OF EVIDENCE

Level III.

Estimating pulmonary function after surgery for adolescent idiopathic scoliosis using biplanar radiographs of the chest with 3D reconstruction

AIMS

This study addressed two questions: first, does surgical correction of an idiopathic scoliosis increase the volume of the rib cage, and second, is it possible to evaluate the change in lung function after corrective surgery for adolescent idiopathic scoliosis (AIS) using biplanar radiographs of the ribcage with 3D reconstruction?

METHODS

A total of 45 patients with a thoracic AIS which needed surgical correction and fusion were included in a prospective study. All patients underwent pulmonary function testing (PFT) and low-dose biplanar radiographs both preoperatively and one year after surgery. The following measurements were recorded: forced vital capacity (FVC), slow vital capacity (SVC), and total lung capacity (TLC). Rib cage volume (RCV), maximum rib hump, main thoracic curve Cobb angle (MCCA), medial-lateral and anteroposterior diameter, and T4-T12 kyphosis were calculated from 3D reconstructions of the biplanar radiographs.

RESULTS

All spinal and thoracic measurements improved significantly after surgery (p < 0.001). RCV increased from 4.9 l (SD 1) preoperatively to 5.3 l (SD 0.9) (p < 0.001) while TLC increased from 4.1 l (SD 0.9) preoperatively to 4.3 l (SD 0.8) (p < 0.001). RCV was correlated with all functional indexes before and after correction of the deformity. Improvement in RCV was weakly correlated with correction of the mean thoracic Cobb angle (p = 0.006). The difference in TLC was significantly correlated with changes in RCV (p = 0.041). It was possible to predict postoperative TLC from the postoperative RCV.

CONCLUSION

3D rib cage assessment from biplanar radiographs could be a minimally invasive method of estimating pulmonary function before and after spinal fusion in patients with an AIS. The 3D RCV reflects virtual chest capacity and hence pulmonary function in this group of patients. Cite this article: Bone Joint J 2022;104-B(1):112-119.

Are we neglecting long-term effects of vertebral shortening on pulmonary function in spinal tuberculosis?

PURPOSE

In developing part of the world, it is common to see complete destruction of vertebral bodies in tuberculosis. Our study aims to assess the effect of spinal tuberculosis with vertebral shortening on pulmonary function.

METHODS

Fifty cases of spinal TB (14 males, 36 females) managed both operatively and non-operatively, who presented to tertiary care institute between years 2011 and 2016 were assessed. Vertebral height loss was assessed by spinal deformity index (SDI). All patients underwent pulmonary function testing using same equipment sitting in upright position.

RESULTS

Mean age was 27.9 years (27.9 ± 11.9). 11 patients with mean SDI of 2.7 ± 1.1 showed normal lung function. 36 patients showed restrictive pattern of which 12 were mild, 14 were moderate and 10 showed severe pattern with a mean SDI of 3.8 ± 1.2, 5.6 ± 1.3 and 6.1 ± 1.4, respectively. 3 cases showed obstructive pattern. As the apex of curve shifted proximally, FVC% reduced. Increase in SDI value was associated with a fall in the vital capacity and FEV₁. Increase in the kyphotic angle was associated with a deleterious effect on PFT results.

CONCLUSIONS

Risk stratification of pulmonary dysfunction resulting from vertebral body height loss due to kyphosis will emphasize the need for early detection of spinal tuberculosis before deformity occurs.

The 18-cm Thoracic-Height Threshold and Pulmonary Function in Non-Neuromuscular Early-Onset Scoliosis: A Reassessment

Thoracic spine height is cited as a crucial outcome measure in the treatment of early-onset scoliosis (EOS) because of its reported relationship to pulmonary function tests (PFTs). An 18-cm threshold has been proposed, although this single parameter might be overly simplistic for cases of different etiologies and deformity magnitude. We aimed to reevaluate pulmonary function in patients undergoing corrective surgery, assessing the role of residual scoliosis as well as spine elongation

Thoracic Morphology and Bronchial Narrowing Are Related to Pulmonary Function in Adolescent Idiopathic Scoliosis

BACKGROUND

In adolescent idiopathic scoliosis (AIS), lung function impairment is not necessarily related to the coronal spinal deformity. Recently, right-sided bronchial narrowing has been reported in thoracic AIS. The aim of this study was to describe the relation of chest and spinal deformity parameters, bronchial narrowing, and lung volumes with pulmonary function in preoperative AIS.

METHODS

Spinal radiographs, low-dose computed tomographic (CT) scans of the spine including the chest, and pulmonary function tests were retrospectively collected for 85 preoperative patients with thoracic AIS in 2 centers and were compared with 14 matched controls. Three-dimensional lung and airway reconstructions were acquired. Correlation analysis was performed in which radiographic spinal parameters, CT-based thoracic deformity parameters (rib-hump index [RHi], spinal penetration index, endothoracic hump ratio, hemithoracic-width ratio), lung volume asymmetry, and bronchial cross-sectional area were compared with percent-of-predicted spirometry results.

RESULTS

Forty-one patients (48%) had a percent-of-predicted forced expiratory volume in 1 second (FEV1%) or percent-of-predicted forced vital capacity (FVC%) of <65%, and 17 patients (20%) had obstructive lung disease. All thoracic deformity parameters correlated significantly with FEV1% and FVC%; RHi was found to be the best correlate (rs = -0.52 for FEV1% and -0.54 for FVC%). Patients with AIS with impaired pulmonary function had hypokyphosis, a larger rib hump, increased spinal and thoracic rotation, a narrower right hemithorax, and increased intrusion of the spine into the chest. Spinal intrusion correlated with right-sided bronchial narrowing, relative right lung volume loss, and decreased FEV1% and FVC%. Multivariate regression including spinal and thoracic deformity parameters, lung volume asymmetry, and airway parameters could explain 57% of the variance in FEV1% and 54% of the variance in FVC%.

CONCLUSIONS

Chest intrusion by the endothoracic hump is related to right-sided bronchial narrowing and lung function loss in preoperative AIS. The findings support the theory that ventilatory dysfunction in thoracic AIS is not only restrictive but frequently has an obstructive component, especially in patients with hypokyphosis. RHi is the most predictive chest parameter for lung function loss.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Does pulmonary function improve after surgical correction of adult idiopathic scoliosis?

PURPOSE

The aim was to investigate pulmonary function after surgical correction of adult idiopathic scoliosis.

METHODS

This study included 146 adult scoliosis patients aged 20-50 years (main curve in thoracic spine). Respiratory function was assessed as predicted forced vital capacity (%FVC) and the ratio of forced expiratory volume in 1 s / FVC (%FEV₁) preoperatively and 2 years postoperatively and classified as a normal function (≥ 80%), mild impairment (≥ 65% and < 80%), and moderate impairment (< 65%).

RESULTS

Preoperative %FVC and %FEV₁ were 85.3% and 85.4%, which were 81.5% and 87.5% at 2 years post-surgery. The preoperative %FVC was mild and moderate in 39 (26.7%) and 12 patients (11.6%), respectively. The %FVC significantly improved (+ 6.2% ± 11.4%, P < 0.001) postoperatively for moderate severity but significantly decreased postoperatively (- 6.4% ± 9.4%, P < 0.001) for normal function. The preoperative %FEV₁ was mild and moderate in 27 (18.5%) and 0 patients, respectively. The %FEV1 significantly improved postoperatively (6.3% ± 5.3%, P < 0.001) for mild severity but did not significantly change for normal severity. Twenty-three (15.8%) and 41 (28.1%) patients showed improved ⊿%FVC and ⊿% FEV₁ > 5%. Logistic regression analysis showed that preoperative %FVC and %FEV₁ severities were independent factors affecting postoperative recovery of %FVC (OR 0.95) and %FEV₁ (OR 0.85).

CONCLUSION

Pulmonary function improved in patients with preoperative pulmonary impairment of < 65% in %FVC and < 80% in %FEV₁, and the real improvement was limited to patients with severe preoperative impairment.

A Novel Classification of 3D Rib Cage Deformity in Subjects With Adolescent Idiopathic Scoliosis

STUDY DESIGN

This was a multicentric cross-sectional descriptive study.

OBJECTIVE

To analyze patterns of 3D rib cage deformity in subjects with adolescent idiopathic scoliosis (AIS) and their relationship with the spinal deformity.

SUMMARY OF BACKGROUND DATA

Subjects with AIS present with rib cage deformity that can affect respiratory functions. The 3D rib cage deformities in AIS and their relationship to the spinal deformity are still unelucidated.

METHODS

A total of 200 AIS and 71 controls underwent low-dose biplanar x-rays and had their spine and rib cage reconstructed in 3-dimensional (D). Classic spinopelvic parameters were calculated in 3D and: rib cage gibbosity, thickness, width, volume and volumetric spinal penetration index (VSPI). Subjects with AIS were classified as: group I with mild rib cage deformity (n=88), group II with severe rib cage deformity (n=112) subgrouped into IIa (high gibbosity, n=48), IIb (high VSPI, n=48), and IIc (both high gibbosity and VSPI, n=16).

RESULTS

Groups IIa and IIb had a higher Cobb angle (33 vs. 54 degrees and 46 degrees, respectively) and torsion index (11 vs. 14 degrees and 13 degrees, respectively) than group I. Group IIb showed more severe hypokyphosis (IIb=21 degrees; IIa=33 degrees; I=36 degrees; control=42 degrees) with a reduced rib cage volume (IIb=4731 cm3; IIa=4985 cm3; I=5257 cm3; control=5254 cm3) and thickness (IIb=135 mm; IIa=148 mm; I=144 mm; control=144 mm). Group IIa showed an increasingly large local gibbosity descending from proximal to distal levels and did not follow the axial rotation of the spine. Group IIc showed characteristics of both groups IIa and IIb.

CONCLUSIONS

This new classification of 3D rib cage deformity in AIS shows that the management of cases with high VSPI (groups IIb and IIc) should focus on restoring as much kyphosis as possible to avoid respiratory repercussions. Treatment indications in groups I and IIa would follow the consensual basic principles reported in the literature regarding bracing and surgery.

Spirometry Examination of Adolescents with Thoracic Idiopathic Scoliosis: Is Correction for Height Loss Useful?

Loss of body height is observed in patients with idiopathic scoliosis (IS) due to spine curvatures. The study compared pulmonary parameters obtained from spirometry examination considering the measured versus the corrected body height. One hundred and twenty adolescents with Lenke type 1 or 3 IS who underwent preoperative spirometry examination and radiographic evaluation were enrolled. The mean thoracic Cobb angle was 68° ± 12.6, range 48-102°. The difference between the measured and the corrected body height increased with the greater Cobb angle. Using the corrected body height instead of the measured body height significantly changed the predicted values of pulmonary parameters and influenced the interpretation of the pulmonary testing results.

The effect of direct vertebral rotation on the spine parameters (coronal and sagittal) in adolescent idiopathic scoliosis

BACKGROUND

Idiopathic scoliosis is accompanied by postural alterations, instability of gait, and functional disabilities. The objective was to verify radiographic parameters (coronal and sagittal) of adolescents with idiopathic scoliosis (AIS) pre- and post-surgery with direct vertebral rotation (DVR), associated with type 1 osteotomies in all segments (except the most proximal) and type 2 in the periapical vertebrae of the curves.

METHODS

A prospective study design was employed in which 41 AIS were evaluated and compared pre- and post-surgery. Scoliosis was confirmed by a spine X-ray exam (Cobb angle). Eight radiographic parameters were measured: Cobb angles (thoracic proximal and distal), segmental kyphosis, total kyphosis, lumbar lordosis, pelvic incidence, sacral slope, and pelvic tilt.

RESULTS

The Cobb angle averaged 51.3∘± 14.9∘. Post-surgery, there were significant reductions for the following spine measurement parameters: Cobb angle thoracic proximal (p= 0.003); Cobb angle thoracic distal (p= 0.001); Cobb angle lumbar (p= 0.001); kyphosis (T5-T12, p= 0.012); and kyphosis (T1-T12, p= 0.002). These reductions showed the effectiveness of surgical correction to reduce Cobb angles and improve thoracic kyphosis. The values obtained for lumbar lordosis, pelvic incidence, sacral slope, and pelvic tilt were not significantly different pre- and post-surgery.

CONCLUSION

The surgical technique of DVR in AIS proved to be effective in the coronal and sagittal parameters directed at Cobb angles and thoracic kyphosis in order to favor the rehabilitation process.

Scoliosis Management for Primary Care Practitioners

For many families, the possibility that their child may have scoliosis causes great anxiety because their child may be deformed for life, may need to wear a brace for years, or may need to undergo a large and dangerous operation. For most families, these fears are groundless. Up to 3% of the population has a spinal curvature, most of which are small curves that may not need referral or repeated imaging. Many adolescents with scoliosis do well and do not need to wear a brace or have surgery.

CARDIORESPIRATORY FUNCTION OF PATIENTS WITH ADOLESCENT IDIOPATHIC SCOLIOSIS

ABSTRACT Objective: Adolescent idiopathic scoliosis (AIS) is a spinal deformity that can cause cardiorespiratory dysfunction, contributing to decreases in tolerance for aerobic exercise (TAE) and in functionality. The objective is to assess the TAE and lung capacity of patients who underwent corrective AIS surgery in the pre- (PRE) and postoperative (POST) periods. Methods: Sixty individuals, PRE (n=30, age: 18.5±2.4 years) and POST (n=30, age: 24.5±4.5 years), participated in the study. The forced vital capacity (FVC), the forced expiratory volume in the first second (FEV1) and the FEV1/FVC ratio, as well as the maximum inspiratory and expiratory pressure were verified. The TAE was assessed by the distance travelled in the 6-minute walk test (6MWT), together with blood pressure, heart rate, respiratory rate and peripheral oxygen saturation measured at the beginning and at the end of the test. Results: A mild restrictive pattern in lung function and reduced expiratory muscle strength were observed in both groups, but with no difference between the PRE and POST groups. No difference was found between the PRE (534±67.1 m) and POST (541± 69.5 m) groups for the distance travelled in the 6MWT, though both were below the predicted percentage (82.8±10.0% and 84.8±10.9%, respectively). Hemodynamic and respiratory changes caused by the 6MWT were observed, except for the peripheral oxygen saturation. Conclusion: The results suggest that even after surgical correction, patients with AIS continue to have low TAE. Level of evidence III; Therapeutics Study - Investigation of Treatment Results / Case-control study.

Three-dimensional reconstruction image by biplanar stereoradiography reflects pulmonary functional states inadolescent idiopathic scoliosis

This study investigated whether the rib cage parameters estimated based on reconstructed three-dimensional (3D) images with biplanar stereoradiography reflect pulmonary functional states in adolescent idiopathic scoliosis (AIS) patients. A total of 67 Lenke type 1 or 2 AIS patients (59 females and 8 males, mean age 14.4 years) were enrolled. All patients underwent preoperative pulmonary functional tests (PFT) and biplanar stereoradiography. Vital capacity (VC) and forced vital capacity (FVC) pulmonary functional data were collected. Rib-cage parameters (maximum thickness, maximum width, thoracic index (TI), rib hump (RH), rib-cage volume (RCV), spinal penetration index (SPI), endothoracic hump ratio (EHR), vertebra-sternum angle (VSA), rib vertebral angle difference (RVAD), and vertebral lateral decentering (VLD)) were quantified from 3D images. Patients were divided into two groups: restrictive lung disorder (RLD) (%FVC < 80%) and non-RLD (%FVC ≥ 80%). The maximum width and RCV were significantly correlated with VC (p < 0.0001), and FVC (p < 0.0001). RH, EHR, and VSA were negatively correlated with %FVC (p < 0.01). TI, SPI, and RVAD were not correlated with any pulmonary parameters. The maximum widths of RLD patients were significantly shorter than those of the non-RLD patients (218.3 mm vs. 229.7 mm, p < 0.01). The RCV of RLD patients was significantly smaller than that of the non-RLD patients (3.94 L vs. 4.49 L, p < 0.0001). The maximum width and RCV measured by 3D images with biplanar stereoradiography reflected pulmonary functional variables in patients with AIS.

Anterior Vertebral Body Tethering for Adolescent Idiopathic Scoliosis: Early Results and Future Directions

Anterior vertebral body tether (AVBT) is a nonfusion surgical procedure for correction of scoliosis in skeletally immature individuals. With US Food and Drug Administration approval in 2019, AVBT technology is spreading and early to midterm reports are being published. Early clinical reports are promising while precise indications, outcomes, complication profiles, and best practices are being established. Patients who are skeletally immature and wish to avoid a fusion surgery may benefit from this procedure. This article highlights the translational science foundation, early to midterm clinical reports, and future directions for this growing technique in pediatric spinal deformity surgery.

Pulmonary Implications of Pediatric Spinal Deformities

"Pediatric spinal deformities may be associated with pulmonary complications in a patient's lifetime. A review of the diagnosis of spinal abnormalities includes classifications of scoliosis and kyphosis, correlating physical examination findings and radiographic interpretation. The natural history of untreated spine deformities is reviewed along with the associated altered pulmonary compromise. Treatment options for children affected by spinal deformities are discussed, including the relative indications, the efficacy, pros and cons of different treatment options, along with the evidence to support these. This overview of spine deformities includes research outcomes to support the care of these pediatric patients."

Does thoracoplasty adversely affect lung function in complex pediatric spine deformity? A 2-year follow-up review

STUDY DESIGN

Retrospective review of prospective multi-center cohort.

OBJECTIVE

To investigate the impact of thoracoplasty on pulmonary function at 2-year follow-up among complex pediatric spine deformity patients. Complex pediatric spine deformities may be associated with significant rib prominence causing body image concerns. Surgical correction of spine deformity may include thoracoplasty to correct the rotational prominence. Some surgeons refrain from performing thoracoplasty due to its purported negative effect on pulmonary function. There is paucity of literature on the effect of thoracoplasty on pulmonary function at 2-year follow-up in pediatric patients with complex spine deformity.

METHODS

We reviewed data of 312 patients (> 100°, with or without vertebral column resection (VCR)) or (< 100° with VCR)) from an international multicenter database. Data of 106 patients with complete radiographic and pulmonary function test (PFT) assessment with a minimum of 2-year follow-up was analyzed. Paired t test was performed to compare pre-op and 2-year PFT results. PFT comparison was stratified based on thoracoplasty status (thoracoplasty: Group 1 vs. no thoracoplasty: Group 2).

RESULTS

106 patients (61 patients Group 1 vs. 45 in Group 2). The average age and gender ratio were similar in both groups (p  >  0.05). Group 1 had significantly lower body mass index (BMI) compared to Group 2 (18.4 kg m^-2 ± 2.8 vs. 19.9 kg m^-2  ±  4.8, p  =  0.0351). The average baseline coronal and sagittal Cobbs were larger for Group 1 relative to Group 2 (p  < 0.05). The distribution of deformity etiology and curve types, and apices were similar between the two groups (p  >  0.05). The rate of pre-op utilization of halo gravity traction (HGT) was 52.5% vs. 26.7% (p  =  0.008), at an average duration of 103 days vs. 47 days, p  =  0.0001. The rate of surgical osteotomies was similar in both groups. Estimated blood volume (EBV) loss was greater in Group 1 (63.1% vs. 43.1%, p  =  0.0012). Post-op coronal and sagittal Cobb correction was similar in both groups. The incidence of post-op pulmonary complication was similar in both groups (8.2% vs. 8.9%, p  =  0.899). Baseline and 2-year follow-up PFT did not differ significantly between and within the groups. Vertebral column resection (VCR) did not negatively affect PFT in both groups.

CONCLUSION

Despite higher curve magnitudes in patients undergoing surgical correction and thoracoplasty for complex pediatric spine deformity, our findings revealed that thoracoplasty does not negatively affect pulmonary function at 2-year follow-up.

The correlation between spinal and chest wall deformities and pulmonary function in Marfan syndrome

PURPOSE

Scoliosis, chest wall deformities and pulmonary involvement are common features of Marfan syndrome (MFS). We aimed to assess the impact of spinal and chest wall deformities on pulmonary function in paediatric MFS patients with a surgically managed spinal deformity.

METHODS

In this multicentre retrospective study, spirometry, lung volumes and radiographic imaging were performed on 26 MFS patients between the ages of seven and 18 years who were undergoing planned spinal fusion surgery for spinal deformity. A correlation analysis assessed the relationship between radiographic measurements of spinal and chest wall deformities and predicted total lung capacity (TLC), forced vital capacity (FVC) and the ratio between forced expiratory volume in one second and FVC (FEV1/FVC).

RESULTS

In total, 18 patients (70%) had impaired pulmonary function. Thoracic kyphosis (mean 19.3°; -32° to 54°) had a strong positive correlation with FEV1/FVC (r = 0.65; p < 0.001). Significant decrease in FEV1/FVC below 80% occurred at kyphosis under 15° (p = 0.004). Kyphosis had a moderate negative correlation with FVC (r = -0.43; p = 0.03). Chest wall deformity had a strong negative correlation with FEV1/FVC (r = -0.61; p = 0.001). The magnitude of the thoracic curve (mean 55.2°; 28° to 92°) had a significant moderate negative correlation with TLC (r = -0.45; p = 0.04).

CONCLUSION

In MFS, three factors correlate with decreased pulmonary function measures: hypokyphosis, increasing chest wall deformity and increasing coronal curve magnitude. Hypokyphosis and increased chest wall deformity correlated with diminished FEV1/FVC; increasing thoracic spinal curvature with diminished TLC. Further analysis with a larger cohort will help better define the relationship between these deformities and pulmonary function in this unique population.

LEVEL OF EVIDENCE

IV.

Predicting preoperative pulmonary function in patients with thoracic adolescent idiopathic scoliosis from spinal and thoracic radiographic parameters

PURPOSE

The objective was to analyse the effect of thoracic morphology on pulmonary function in adolescent idiopathic scoliosis (AIS) to predict preoperative lung function.

METHODS

A total of 170 consecutive preoperative patients (average age 15.1 years) with Lenke 1 and 2 AIS underwent pulmonary function testing. Thirteen deformity parameters, including rib hump size, rib asymmetry, spinal intrusion and thoracic/lung dimensions in the sagittal and coronal plane, were measured on whole-spine radiographs. Lung function parameters were expressed as z-scores. Correlation and regression analysis of these parameters with lung function were performed.

RESULTS

Mean thoracic Cobb (MT) was 69.1°, and mean T5-T12 thoracic kyphosis (TK) was 21.8°. MT correlated significantly with FEV₁ and FVC (r_s = - 0.40 and - 0.38). TK correlated weakly with FEV₁ and FEV₁/FVC (r_s = 0.23 and 0.25). FEV₁ and FVC were best predicted by the inverse apical vertebra body-rib ratio (AVBRr^-1, r_s = 0.46 and 0.42), rib hump depth index (RHDi, r_s = - 0.52 and - 0.50) and spinal intrusion ratio (SIr, r_s = - 0.50 and - 0.45). The kyphosis-lordosis index (KLi) correlated with FEV₁/FVC (r_s = 0.29). Multivariate regression analysis of coronal and sagittal Cobb angles produced a model which explained 35% and 30% of the variance in FEV₁ and FVC, whilst a regression model consisting of AVBRr^-1 and SIr was able to predict 54% and 48%.

CONCLUSION

AVBRr^-1, RHDi and SIr measured on posterior-anterior and lateral radiographs provide better estimations of lung function in preoperative AIS patients than Cobb measurements. KLi was an indicator of airway obstruction as measured by FEV₁/FVC.

Flexibility of the thoracic curve and three-dimensional thoracic kyphosis can predict pulmonary function in nonoperatively treated adult patients with adolescent idiopathic scoliosis

BACKGROUND

Although several radiographic predictors for pulmonary function in adolescent patients have been reported, those in adult patients remain unclear. Therefore, we aimed to investigate the associations between spinal deformity and pulmonary function in nonoperatively treated adult patients with adolescent idiopathic scoliosis (AIS).

METHODS

Of 319 patients treated nonoperatively for AIS, 90 (average age, 40.0 ± 6.5 years) underwent both full-length standing radiographs and pulmonary function test. Standard two-dimensional (2-D) radiographic measurements were performed. Three-dimensional thoracic kyphosis (3-D TK) was calculated from 2-D standing radiograph data using a validated formula: 3-D TK (°) = 18.1 + 0.81 × (2-D TK) + 0.54 × (Cobb angle of thoracic curve). 3-D TK was defined as the sum of segmental kyphosis between T5 and T12, which eliminates the overestimation of TK in 2-D measurements due to rotational deformity. Bivariable correlation analysis, followed by a stepwise multiple linear regression analysis, was performed.

RESULTS

The average Cobb angle of the thoracic curve at the time of survey was 49.4° ± 14.6° with flexibility of 37.5% ± 18.2%. Thoracic curve magnitude, flexibility, apical vertebral rotation and translation, and 3-D TK were significantly correlated with percent-predicted forced vital capacity (%FVC) and expiratory volume in 1 s (%FEV1.0). Stepwise multiple regression analysis showed that curve flexibility and 3-D TK were significant, independent predictors of %FVC (R² = 0.358) and %FEV1.0 (R² = 0.335), curve flexibility having a greater impact (standardized coefficient > 0.45) than 3-D TK (<0.32).

CONCLUSIONS

Our results indicate that nonoperatively treated patients with AIS should be recommended to maintain flexibility of the thoracic curve to prevent future pulmonary impairment. Moreover, 3-D TK is another independent predictor of pulmonary function, which suggests that segmental sagittal alignment is a component of deformity correction to focus on.

Long-term pulmonary function after posterior spinal fusion in main thoracic adolescent idiopathic scoliosis

Background

Adolescent idiopathic scoliosis (AIS) patients typically undergo surgical treatment as teenagers, follow-ups of >5 years are necessary to evaluate effects on peak pulmonary reserves. However, limited data is available regarding the long-term (>10 years) effects of surgical intervention on pulmonary function (PF) in patients with thoracic AIS.

Objective

To provide long-term (>10 years) information on the PF after posterior spinal fusion for treating main thoracic AIS. We especially investigated whether surgical correction for AIS led to impairment of the PF.

Methods

A total of 35 patients with main thoracic AIS treated with posterior spinal fusion were included. Radiographs and PF tests, which included measurements of absolute and percent-predicted values of forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV₁), were evaluated.

Results

Mean age at surgery was 14.9 years (12–19 years). Mean follow-up period was 15.1 years (10–24 years). Although the final postoperative FVC and FEV₁ absolute values were higher than the preoperative values, the differences were not statistically significant (p = 0.22 and p = 0.08, respectively). Percent-predicted FVC and FEV₁ values between preoperative and final postoperative measurements were not statistically different (p = 0.63 and p = 0.29, respectively). However, for the patients who presented with pulmonary impairment preoperatively, both the FVC and FEV₁ significantly increased at the final follow-up (p = 0.01 and p = 0.01, respectively).

Conclusions

Long-term results of AIS patients who underwent posterior spinal fusion in main thoracic curves demonstrated absolute and percent-predicted PF test values similar to preoperative measurements; thus, indicating that posterior spinal fusion did not decrease PF 15 years after the initial surgery. Instead, patients with severe preoperative pulmonary impairment might show some degree of improvement after surgery.

The effect of 50% oxygen on PtCO2 in patients with stable COPD, bronchiectasis, and neuromuscular disease or kyphoscoliosis: randomised cross-over trials

BACKGROUND

High-concentration oxygen therapy causes increased arterial partial pressure of carbon dioxide (PaCO2) in patients with COPD, asthma, pneumonia, obesity and acute lung injury. The objective of these studies was to investigate whether this physiological response to oxygen therapy occurs in stable patients with neuromuscular disease or kyphoscoliosis, and bronchiectasis.

METHODS

Three randomised cross-over trials recruited stable patients with neuromuscular disease or kyphoscoliosis (n = 20), bronchiectasis (n = 24), and COPD (n = 24). Participants were randomised to receive 50% oxygen and 21% oxygen (air), each for 30 min, in randomly assigned order. The primary outcome was transcutaneous partial pressure of carbon dioxide (PtCO2) at 30 min. The primary analysis was a mixed linear model.

RESULTS

Sixty six of the 68 participants had baseline PtCO2 values < 45 mmHg. The intervention baseline adjusted PtCO2 difference (95% CI) between oxygen and room air after 30 min was 0.2 mmHg (- 0.4 to 0.9), P = 0.40; 0.5 mmHg (- 0.2 to 1.2), P = 0.18; and 1.3 mmHg (0.7 to 1.8), P < 0.001, in the neuromuscular/kyphoscoliosis, bronchiectasis and COPD participants respectively.

CONCLUSIONS

The small increase in PtCO2 in the stable COPD patients with high-concentration oxygen therapy contrasts with the marked increases in PaCO2 seen in the setting of acute exacerbations of COPD. This suggests that the model of studying the effects of high-concentration oxygen therapy in patients with stable respiratory disease is not generalisable to the use of oxygen therapy in the acute clinical setting. Appropriate studies of high-concentration compared to titrated oxygen in acute clinical settings are needed to determine if there is a risk of oxygen-induced hypercapnia in patients with neuromuscular disease, kyphoscoliosis or bronchiectasis.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry ACTRN12615000970549 Registered 16/9/15, ACTRN12615000971538 Registered 16/9/15 and ACTRN12615001056583 Registered 7/10/15.

Essential lordosis revisited

AIMS

Significant correction of an adolescent idiopathic scoliosis in the coronal plane through a posterior approach is associated with hypokyphosis. Factors such as the magnitude of the preoperative coronal curve, the use of hooks, number of levels fused, preoperative kyphosis, screw density, and rod type have all been implicated. Maintaining the normal thoracic kyphosis is important as hypokyphosis is associated with proximal junctional failure (PJF) and early onset degeneration of the spine. The aim of this study was to determine if coronal correction per se was the most relevant factor in generating hypokyphosis.

METHODS

A total of 95 patients (87% female) with a median age of 14 years were included in our study. Pre- and postoperative radiographs were measured and the operative data including upper instrumented vertebra (UIV), lower instrumented vertebra (LIV), metal density, and thoracic flexibility noted. Further analysis of the post-surgical coronal outcome (group 1 < 60% correction and group 2 ≥ 60%) were studied for their association with the postoperative kyphosis in the sagittal plane using univariate and multivariate logistic regression.

RESULTS

Of the 95 patients, 71.6% (68) had a thoracic correction of > 60%. Most (97.8%) had metal density < 80%, while thoracic flexibility > 50% was found in 30.5% (29). Preoperative hypokyphosis (< 20°) was present in 25.3%. A postoperative thoracic hypokyphosis was four times more likely to occur in patients with thoracic correction ≥ 60% (odds ratio (OR) 4.08; p = 0.005), after adjusting for confounding variables. This association was not affected by metal density, thoracic flexibility, LIV, UIV, age, or sex.

CONCLUSION

Our study supports the 'essential lordosis' hypothesis of Roaf and Dickson, i.e. with a greater ability to translate the apical vertebra towards the midline, there is a commensurate lengthening of the anterior column due to the vertebral wedging. Cite this article: Bone Joint J 2020;102-B(4):513-518.

Sagittal Balance in Adult Idiopathic Scoliosis

STUDY DESIGN

A narrative review article study.

OBJECTIVE

The objective of this study was to highlight guiding principles and challenges faced with addressing sagittal alignment in patients with adult idiopathic scoliosis (AIS) and to discuss effective surgical strategies based upon our clinical experience.

SUMMARY OF BACKGROUND DATA

Previous research and guidelines for the treatment of AIS have focused on the correction of spinal deformity in the coronal and axial planes. Failure to address sagittal deformity has been associated with numerous adverse clinical outcomes.

METHODS

This is a review of the current body of literature and a description of the rod derotation surgical technique for correction in the sagittal plane.

RESULTS

Several studies have offered general goals for postoperative radiographic measures in the sagittal plane for patients with AIS. However, these guidelines are evolving as diagnostic and therapeutic modalities continue to improve. The rod derotation surgical technique through differential metal rods is one method to potentially address sagittal balance in AIS.

CONCLUSIONS

Alignment in the sagittal plane is a unique challenge facing surgeons for patients with AIS. Further research with an assessment of functional outcomes and longer follow-up is needed to more precisely guide treatment principles.

LEVEL OF EVIDENCE

Level IV.

The Association Between the Classification of Early-onset Scoliosis and Smith Complications After Initiation of Growth-friendly Spine Surgery: A Preliminary Study

BACKGROUND

Early-onset scoliosis (EOS) is a complex, heterogeneous condition involving multiple etiologies, genetic associations, and treatment plans. In 2014, Williams and colleagues proposed a classification system of EOS (C-EOS) that categorizes patients by etiology, Cobb angle, and kyphosis. Shortly after, Smith and colleagues validated a classification system to report complications of growth-friendly spine instrumentation. Severity refers to the level of care and urgency required to treat the complication, and can be classified as device-related or disease-related complications. The purpose of this study was to investigate if C-EOS can be used as a reliable predictor of Smith complications to better risk stratify these young, surgical patients.

METHODS

This study queried retrospective data from a large multicenter registry with regard to growth-friendly spine instrumentation in the EOS population. One-hundred sixteen patients were included in final data analysis to investigate the outcomes of their growth-friendly procedures according to the Smith complication classification system.

RESULTS

There were 245 Smith complications distributed among 116 patients included in this study (2.1 complications per patient). The majority of the complications were device related requiring at least one unplanned trip to the operating room (Smith Device Complication IIA or IIB; 111 complications). There were no complications that caused abandonment of growth-friendly instrumentation (Smith Complication III) and no mortalities (Smith Complication IV). The most severely affected EOS group was the hyperkyphotic syndromic group with a major curve angle >50 degrees (S3+), with 3.4 complications per patient. The least affect EOS group was the hyperkyphotic congenital group with a major curve angle between 20 and 50 degrees, with 0.3 complications per patient.

CONCLUSIONS

The C-EOS simplifies a complex pathology and the Smith complication classification scheme creates a language to discuss treatment of known complications of growth-friendly spine surgery. Although there is an association between more advanced C-EOS and Smith complications, there does not appear to be a correlation that can satisfy a risk stratification at this time.

LEVEL OF EVIDENCE

Level II.

Adaptation to reduced lung function in children and young people with spinal deformity

BACKGROUND

Severe scoliosis can affect respiratory function in growing patients and produce cardiopulmonary complications, leading to significant morbidity. The development of spinal deformity may impact on young patients' level of function and reported quality of life (QOL). The aim of this study was to investigate the relationship between lung function, exercise capacity and quality of life in young patients with spinal deformity.

METHODS

This is a retrospective analysis of 104 patients (31% male, 69% female with mean age 14.9yrs). 77% of patients had an adolescent idiopathic scoliosis, with the remainder having other scoliosis diagnoses or Scheuermann's kyphosis. Principal outcomes included Spirometry [FEV₁, FVC], Whole Body Plethysmography, Cardiopulmonary Exercise Testing [CPET] and patient outcome questionnaires (with SRS-22). CPET measures included maximal exercise capacity [VO_2peak] as well as VO₂ at ventilatory threshold [VT] expressed as %predicted VO_2max-a measure of physical conditioning, and minute ventilation [V_E] from which breathing reserve [BR] could be calculated.

RESULTS

Mean (±SD) main thoracic scoliosis was 59.9⁰ (±15.2⁰), and mean kyphosis in those with Scheuermann's condition was 95.3⁰ (±11.5⁰). No correlation was elicited between FEV₁ or FVC (%predicted) and VO_2peak (%predicted) in this patient cohort. Greater thoracic curves were associated with lower FEV₁ (%predicted), r = -0.343, p = 0.001, FVC (%predicted), r = -0.307, p = 0.003 and BR (%) at the end of exercise (r = -0.-0.459, p < 0.001). The patient cohort had a mean (sd) VO₂peak of 98(17) %predicted, with greater VO₂peak levels recorded in female subjects, those of younger age and those with higher scoliosis angles. Those with better lung function [FEV₁ (%predicted)] had better BR (%) at the end of exercise (r = 0.483, p < 0.001). SRS-22 scores correlated significantly with VO_2peak (%predicted) (total SRS-22 versus VO_2peak (%predicted), r = 0.336, p = 0.002).

CONCLUSION

Larger thoracic scoliotic curves are associated with poorer lung function but better exercise capacity, likely related to higher levels of physical conditioning. Higher QOL scores were recorded in patients who had greater VO_2peak levels, suggesting that exercise capacity may be a protective factor for emotional well-being in patients with spinal deformity.