Relationship between Lung Volume and Pulmonary Function in Patients With Adolescent Idiopathic Scoliosis: Computed Tomographic-based 3-Dimensional Volumetric Reconstruction of Lung Parenchyma

Evaluation of Pulmonary Function After Halo-Pelvic Traction for Severe and Rigid Kyphoscoliosis Utilizing CT with 3D Reconstruction

BACKGROUND

The purpose of the present study was to evaluate changes in pulmonary function, caused by preoperative halo-pelvic traction (HPT) for the treatment of extremely severe and rigid kyphoscoliosis, with use of 3-dimensional computed tomography (3D-CT) reconstruction and pulmonary function tests (PFTs).

METHODS

Twenty-eight patients with severe and rigid scoliosis (Cobb angle, >100°) underwent preoperative HPT and staged posterior spinal fusion. CT, radiographic assessment, and PFT were performed during pre-traction and post-traction visits. The changes in total lung volume were evaluated with use of 3D-CT reconstruction, and the changes in pulmonary function were evaluated with PFTs at each time point. Differences were analyzed with use of 2-tailed paired Student t tests, and correlations were analyzed with use of Spearman rank tests.

RESULTS

None of the patients had pulmonary complications during traction, and all radiographic spinal measurements improved significantly after HPT. The main Cobb angle was corrected from 143.30° ± 20.85° to 62.97° ± 10.83° between the pre-traction and post-traction evaluations. Additionally, the C7-S1 distance was lengthened from 280.48 ± 39.99 to 421.26 ± 32.08 mm between the pre-traction and post-traction evaluations. Furthermore, 3D lung reconstruction demonstrated a notable increase in total lung volume (TLV) (from 1.30 ± 0.25 to 1.83 ± 0.37 L) and maximum lung height (from 176.96 ± 27.44 to 202.31 ± 32.45 mm) between the pre-traction and post-traction evaluations. Moreover, PFTs showed that total lung capacity (TLC) improved between the pre-traction and post-traction evaluations (from 2.06 ± 0.32 to 2.98 ± 0.82 L) and that the changes in T1-T12 distance and maximum lung height were correlated with changes in TLV (p = 0.0288 and p = 0.0007, respectively).

CONCLUSIONS

The application of HPT is a safe and effective method for improving pulmonary function in patients with extremely severe and rigid scoliosis before fusion surgery. The TLV as measured with CT-based reconstruction was greatly increased after HPT, mainly because of the changes in thoracic height.

LEVEL OF EVIDENCE

Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.

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.

Improvement of Pulmonary Function in Arthrogryposis Multiplex Congenita Patients Undergoing Posterior Spinal Fusion Surgery for Concomitant Scoliosis: A Minimum of 3-Year Follow-up

OBJECTIVE

We sought to investigate the long-term outcome of pulmonary function for arthrogryposis multiplex congenita (AMC) patients undergoing posterior spinal fusion (PSF) and to further determine influential factors.

METHODS

Eighteen AMC patients with a minimum of 3-year follow-up after PSF were prospectively collected. All the patients underwent a pulmonary function test before surgery and at the final follow-up. The percentage predicted values of vital capacity (VC%) and forced vital capacity (FVC%) were recorded. The following radiographic parameters were collected including Cobb angle and thoracic kyphosis. The total lung volumes (TLV) were measured on the image of 3-dimensional computed tomography scan by the reconstruction software.

RESULTS

There were 10 males and 8 females with a mean age of 13.8 ± 6.1 years. The mean preoperative VC% and FVC% were 40.5% ± 7.6% and 39.5% ± 4.7%, which were significantly increased to 52.0% ± 7.5% and 51.2% ± 6.8% at the final follow-up (P < 0.001). Besides, there was remarkable improvement in terms of TLV (1.57 ± 0.2 L vs. 2.39 ± 0.6 L, P < 0.001). Remarkable correlations were observed between TLV and pulmonary function tests (r = 0.79, P < 0.001 for VC%; r = 0.78, P < 0.001 for FVC%). Multiple regression analysis showed that 2 variables including Δ thoracic kyphosis and Δ Cobb angle were independently associated with the improvement of pulmonary function.

CONCLUSIONS

The pulmonary function of AMC patients can be well improved through PSF surgery. It was remarkably associated with the correction of curve magnitude and restoration of thoracic kyphosis.

Perioperative concerns in Pott's spine: A review

Pott's disease is the most common granulomatous spine infection caused by tubercle bacilli and is a common site of osseous tuberculosis, accounting for 50–60% of cases. The delay in establishing diagnosis and management results in complications such as spinal cord compression and spinal deformity. The aim of this narrative review is to discuss the perioperative concerns in patients for spine surgery. The literature source for this review was obtained via PubMed, Medline, Google Scholar, Cochrane database of systematic reviews, and textbooks until December 2019. On the literature search, we could not retrieve any review article specifically discussing the perioperative concerns of spinal tuberculosis. Therefore, the aim of the present narrative review is to discuss the perioperative concerns of patients for spine surgery along with the specific concerns related to spinal tuberculosis.

Prevalence and Key Radiographic Spinal Malalignment Parameters Associated with the Risk of Pulmonary Function Impairment in Patients Treated Surgically to Correct Adult Spinal Deformity

Introduction

There is a significant relationship between pulmonary function and degree of spinal deformity, location of apical vertebrae, and coronal imbalance in patients with childhood spinal deformity. By contrast, the pathophysiology, epidemiology, and influence of deformity on respiratory dysfunction in patients with adult spinal deformity (ASD) remain largely unknown. We sought to clarify and compare the prevalence of pulmonary function impairment in patients with ASD with that in patients with lumbar spinal stenosis (LSS), to determine radiographically which spinal malalignment parameters are associated with a risk of respiratory dysfunction, and to determine the association of respiratory dysfunction with corrective surgery.

Methods

We conducted a prospective study of consecutive patients with a diagnosis of ASD or LSS who underwent spinal surgery. We included data from 122 consecutive patients with ASD and 121 consecutive patients with LSS. Parameters were obtained from full-length lateral radiographs taken with the patients standing and in supine and prone positions. We compared respiratory dysfunction between a group of patients with ASD and LSS and determined correlations between respiratory dysfunction and spinopelvic parameters.

Results

Preoperative % forced vital capacity (FVC) of patients with ASD was significantly lower than that of patients with LSS, and the frequency of restrictive ventilatory impairment was significantly higher in those with ASD (15.7%) than those with LSS (7.4%). Thoracolumbar kyphotic curvature (TK) while the patients were in supine position was significantly greater in the group with restrictive ventilatory impairment, and a significant negative correlation was found between %FVC and TK with the patients in supine position. We found no significant improvement of respiratory dysfunction 1 year after surgery.

Conclusions

Spinal deformity is a potential risk factor for restrictive ventilatory impairment in the elderly. We propose that radiographs obtained when patients are in supine position are valuable for evaluating the flexibility of the TK. Rigid TK might be an etiology of restrictive ventilatory impairment in patients with ASD.

Correlation analysis between the pulmonary function test and the radiological parameters of the main right thoracic curve in adolescent idiopathic scoliosis

Background

Scoliosis causes thoracic deformities, and it is necessary to assess these changes in pulmonary function test (PFT). To determine how measurements of spinal and thoracic cage deformities are related to pulmonary function.

Methods

Seventy-two patients with main right thoracic curvature in adolescent idiopathic scoliosis (AIS) underwent a PFT and a radiological parameter evaluation of spinal and thoracic cage deformities. Simple and multiple linear regressions were also used to note whether a combination of variables might better predict PFT values. Means were compared using the two-sample t test or one-way ANOVA with Tukey’s multiple comparison methods.

Results

Forced vital capacity (FVC)% predicted had significantly negative correlations with main thoracic curve Cobb (MT-Cobb) (R² = 0.648, p < 0.001), main thoracic curve-rib hump (MT-RH) (R² = 0.522, p < 0.001), main thoracic curve apical vertebral body-to-rib ratio (MT-AVB-R) (R² = 0.536, p < 0.001), and main thoracic curve apical vertebra translation (MT-AVT) (R² = 0.383, p < 0.001). Multiple regression analysis was performed with FVC% predicted as the dependent variable and MT-Cobb, MT-RH, MT-AVB-R, and MT-AVT as the independent variables. MT-Cobb, MT-RH, MT-AVB-R, and MT-AVT were factors with a significant effect on FVC% predicted (p < 0.001). For 45 patients who had preoperative FVC impairment (FVC% predicted < 80%), their MT-Cobb averaged 76.71°. Twenty-seven patients with normal preoperative FVC (FVC% predicted ≥ 80%) had a smaller mean MT-Cobb of 52.03° (p < 0.001). In other radiological parameters, the impaired FVC group had a MT-AVT of 54.29 mm compared to 38.06 mm for the normal FVC group (p < 0.001). MT-AVB-R averaged 2.92 for the impaired FVC group and 1.78 for the normal FVC group (p < 0.001). MT-RH averaged 28.79 mm for the impaired group and 16.62 mm for the normal group (p < 0.001). Further stratification of preoperative PFT results is divided into three groups. The three groups also showed significant differences in MT-Cobb, MT-RH, MT-AVB-R, and MT-AVT (p < 0.001).

Conclusion

Severe scoliosis leads to an increased degree of thoracic deformity, which increases the risk of lung damage in AIS. Moreover, a more accurate assessment of pulmonary function is achieved through radiological parameters and PFTs.

In-brace alterations of pulmonary functions in adolescents wearing a brace for idiopathic scoliosis

BACKGROUND

Despite the common use of braces to prevent curve progression in idiopathic scoliosis, their functional effects on respiratory mechanics have not been widely studied.

OBJECTIVE

The objective was to determine the effects of bracing on pulmonary function in idiopathic scoliosis.

METHODS

A total of 27 adolescents with a mean age of 14.5 ± 1.5 years and idiopathic scoliosis were included in the study. Pulmonary function evaluation included vital capacity, forced expiratory volume, forced vital capacity, maximum ventilator volume, peak expiratory flow, and respiratory muscle strengths, measured with a spirometer, and patient-reported degree of dyspnea. The tests were performed once prior to bracing and at 1 month after bracing (while the patients wore the brace).

RESULTS

Compared with the unbraced condition, vital capacity, forced expiratory volume, forced vital capacity, maximum ventilator volume, and peak expiratory flow values decreased and dyspnea increased in the braced condition. Respiratory muscle strength was under the norm in both unbraced and braced conditions, while no significant difference was found for these parameters between the two conditions.

CONCLUSION

The spinal brace for idiopathic scoliosis tended to reduce pulmonary functions and increase dyspnea symptoms (when wearing a brace) in this study. Special attention should be paid in-brace effects on pulmonary functions in idiopathic scoliosis.

CLINICAL RELEVANCE

Bracing seems to mimic restrictive pulmonary disease, although there is no actual disease when the brace is removed. This study suggests that bracing may result in a deterioration of pulmonary function when adolescents with idiopathic scoliosis are wearing a brace.

Ventilation/perfusion SPECT/CT in patients with severe and rigid scoliosis: An evaluation by relationship to spinal deformity and lung function

OBJECTIVE

Structural changes of the spine and chest wall associated with SRS result in poor cardiopulmonary function. Comprehensive assessment of pulmonary function is extremely important for patients with SRS before a correction operation. We explore the changes of distribution of lung ventilation and perfusion function in patients with SRS using SPECT/CT and describe the relation between these changes with Cobb angle and FVC%.

PATIENTS AND METHODS

From March 2015 to August 2016, 16 consecutive SRS patients with a mean age of 20.1 years(range 11-36 years) were included in the study. Scoliotic parameters on radiographs were analyzed. FVC% were obtained by spirometry test. Lungs ventilation/perfusion single photon emission computed tomography scans was performed preoperatively in all patients to explore pulmonary ventilation and perfusion function changes. These changes were measured as the deviation form the normal perfusion and ventilation function distribution in right and left lung and correlated with the Cobb angle of main curve and FVC%.

RESULTS

The regional lung ventilation and perfusion function defects were not found in all SRS patients. Ventilation function deviation was a mean 5.7%(range, -3.6% to 10.1%), significantly less than perfusion function deviation of 8.2%(range, -0.3% to 22.2%) (P = 0.015, t = -2.732). Lung ventilation and/or perfusion function deviation did not correlated with Cobb angle and FVC%, respectively. There was significant correlation between lungs ventilation and perfusion function deviation(P = 0.001, r = 0.753).

CONCLUSION

The ventilation and perfusion function distribution were favourable in convex and concave side lung of SRS. Deformity bring about greater lungs perfusion function changes than ventilation function. The measurement of lung ventilation and perfusion function changes may represents an additional functional feature to assess pulmonary function of SRS more comprehensively.

Does Scoliosis Affect Sleep Breathing?

OBJECTIVE

Scoliosis, especially thoracic curves, causes poor pulmonary function. As a result, scoliosis may impair sleep breathing. The literature regarding the relationship between scoliosis and sleep breathing is sparse.

METHODS

Fifty-seven patients with adolescent idiopathic scoliosis or congenital scoliosis and 25 healthy control subjects were included. The wrist sleep monitors was used. Sleep breathing was evaluated with the following parameters: 1) Respiratory Disorders Index (pRDI), indicating mean respiratory events per hour of sleep including apnea, hypoxia, and respiratory effort-related arousal; 2) Apnea and Hypopnea Index (pAHI), expressing the number of apnea and hypopnea events per hour of sleep; and 3) mean and minimal oxygen saturation (Sao₂) during sleep.

RESULTS

No differences in age, sex distribution, and body mass index were found between the two groups. Patients with scoliosis had statistically significant higher pRDI (median, 10.10 vs. 8.65; P = 0.039) and pAHI (median, 1.60 vs. 0.72; P = 0.029) scores than the control group. The minimal SaO₂ value in patients with scoliosis was lower (median, 93% vs. 94%, respectively; P = 0.005), whereas no difference was found in the mean SaO₂ value during sleep. In patients with scoliosis, pAHI scores were higher when lying on the convex side of the thoracic curve compared with the concave side (2.34 vs. 2.28, respectively; P = 0.044), whereas no such difference was observed in the control group.

CONCLUSIONS

Patients with scoliosis have more respiratory events of apnea and hypopnea during sleep than the control group. The minimal SaO₂ value in patients with scoliosis is lower than the normal population. Sleeping on the convex side of the thoracic curve results in higher pAHI scores than on the concave side.

2016 SOSORT guidelines: orthopaedic and rehabilitation treatment of idiopathic scoliosis during growth

BACKGROUND

The International Scientific Society on Scoliosis Orthopaedic and Rehabilitation Treatment (SOSORT) produced its first guidelines in 2005 and renewed them in 2011. Recently published high-quality clinical trials on the effect of conservative treatment approaches (braces and exercises) for idiopathic scoliosis prompted us to update the last guidelines' version. The objective was to align the guidelines with the new scientific evidence to assure faster knowledge transfer into clinical practice of conservative treatment for idiopathic scoliosis (CTIS).

METHODS

Physicians, researchers and allied health practitioners working in the area of CTIS were involved in the development of the 2016 guidelines. Multiple literature reviews reviewing the evidence on CTIS (assessment, bracing, physiotherapy, physiotherapeutic scoliosis-specific exercises (PSSE) and other CTIS) were conducted. Documents, recommendations and practical approach flow charts were developed using a Delphi procedure. The process was completed with the Consensus Session held during the first combined SOSORT/IRSSD Meeting held in Banff, Canada, in May 2016.

RESULTS

The contents of the new 2016 guidelines include the following: background on idiopathic scoliosis, description of CTIS approaches for various populations with flow-charts for clinical practice, as well as literature reviews and recommendations on assessment, bracing, PSSE and other CTIS. The present guidelines include a total of 68 recommendations divided into following topics: bracing (n = 25), PSSE to prevent scoliosis progression during growth (n = 12), PSSE during brace treatment and surgical therapy (n = 6), other conservative treatments (n = 2), respiratory function and exercises (n = 3), general sport activities (n = 6); and assessment (n = 14). According to the agreed strength and level of evidence rating scale, there were 2 recommendations on bracing and 1 recommendation on PSSE that reached level of recommendation "I" and level of evidence "II". Three recommendations reached strength of recommendation A based on the level of evidence I (2 for bracing and one for assessment); 39 recommendations reached strength of recommendation B (20 for bracing, 13 for PSSE, and 6 for assessment).The number of paper for each level of evidence for each treatment is shown in Table 8.

CONCLUSION

The 2016 SOSORT guidelines were developed based on the current evidence on CTIS. Over the last 5 years, high-quality evidence has started to emerge, particularly in the areas of efficacy of bracing (one large multicentre trial) and PSSE (three single-centre randomized controlled trials). Several grade A recommendations were presented. Despite the growing high-quality evidence, the heterogeneity of the study protocols limits generalizability of the recommendations. There is a need for standardization of research methods of conservative treatment effectiveness, as recognized by SOSORT and the Scoliosis Research Society (SRS) non-operative management Committee.

Change in Lung Volume Following Thoracoscopic Anterior Spinal Fusion Surgery: A 3-Dimensional Computed Tomography Investigation

STUDY DESIGN

Lung volumes and thoracic anatomy were measured from low-dose computed tomography (CT) scans preoperatively and 2 years following thoracoscopic anterior spinal fusion (TASF) for adolescent idiopathic scoliosis (AIS).

OBJECTIVE

The aim of this study was to assess changes in lung volume after TASF surgical correction.

SUMMARY OF BACKGROUND DATA

AIS patients are known to have decreased pulmonary function as a consequence of their spinal and ribcage deformity. Several studies have evaluated changes in pulmonary function clinically after scoliosis correction surgery showing varied results. To date, there have been no published studies using CT to evaluate lung volume changes following TASF.

METHODS

Twenty-three female AIS patients with both pre- and 2 years postoperative low-dose CT scans were selected from an ethically approved, historical databank. Three-dimensional lung volumes were reconstructed to determine anatomical lung volumes. Right and left lung volumes, total lung volume, and right-to-left lung volume ratio were obtained as well as hemithoracic symmetry, to indicate the extent of thorax deformity. Cobb angle, rib hump, levels fused in surgery, and patient height were used for correlation analysis with the lung volume results.

RESULTS

Left lung volume, total lung volume, and hemithoracic ratio all increased significantly 2 years after surgery. There was no significant change in right-to-left lung volume ratio (P = 0.36). Statistical regression found significant positive correlation between lung volume changes, reduction in Cobb angle, increase in height, and improvement in hemithoracic symmetry ratio.

CONCLUSION

TASF resulted in a statistically significant increase in lung volume following surgery, as well as improvement in the symmetry of the thoracic architecture; however, the postoperative lung volumes remained in the lower 50th percentile relative to females without thoracic deformity. Furthermore, change in lung volume was significantly correlated with changes in Cobb angle, hemithoracic asymmetry, and increased patient height, which are important consequences of thoracic deformity correction surgery.

LEVEL OF EVIDENCE

3.

Correlation between severity of adolescent idiopathic scoliosis and pulmonary artery systolic pressure: a study of 338 patients

PURPOSE

Study of patients with adolescent idiopathic scoliosis.

OBJECTIVE

To examine the correlation between pulmonary arterial pressure and coronal Cobb angle of idiopathic scoliosis.

METHODS

A total of 338 patients (82.8 % female) with idiopathic scoliosis (average age 15.6 years; range 14-20 years) were included. Preoperatively, the coronal Cobb angle of curvature and the apex location and direction were determined from radiographic records. Tricuspid regurgitation velocity (TRV) and inferior vena cava diameter were also measured using Doppler echocardiography. Pulmonary arterial systolic pressure (sPAP) was calculated from the TRV according to the modified Bernoulli equation and correlations between sPAP and the features of scoliosis were identified by statistical analysis.

RESULTS

Among the 338 patients, there were 305 thoracic curves, 276 (90.5 %) of which were right curves, and 265 thoracolumbar/lumbar curves. sPAP varied from 5.0 to 37.6 mmHg. Pulmonary hypertension could not be excluded in the case of one patient. A mild correlation (Spearman test, correlation coefficient = 0.187, P = 0.001) between sPAP and coronal Cobb angle of the main thoracic (MT) curves was identified. Correlations between sPAP and the degree of other curves were not significant. Patients with sPAP >20 mmHg also had larger thoracic curve angles (mean MT 42.16° vs. 52.45°; U test, P = 0.002). There were no differences in sPAP levels between patients with right and left thoracic curves.

CONCLUSIONS

A mild positive correlation was identified between sPAP and the coronal Cobb angle of the MT curves. There was no relationship between sPAP and the direction of the curvature.

Three-dimensional computed tomography for assessing lung morphology in adolescent idiopathic scoliosis following posterior spinal fusion surgery

OBJECTIVE

To evaluate the changes in lung morphology in subjects with adolescent idiopathic scoliosis (AIS) following posterior spinal fusion surgery.

METHODS

From April 2009 to August 2013, 30 AIS patients (nine males and 21 females) were enrolled in this study. All scans were obtained with the patient in the supine position and the breath held in deep inspiration and performed both before and after surgery. Syngo software was used to manage the computed tomography scan imaging and to calculate the lung volume, lung height and pulmonary cross-sectional area in the apical vertebral plane.

RESULTS

Left lung, right lung and total lung volumes and convex to concave lung volume ratio did not change significantly after corrective surgery. There was a statistically significant improvement in left lung and right lung heights after posterior spinal fusion surgery. However, the pulmonary cross-sectional area in the apical vertebrae plane was smaller postoperatively than preoperatively.

CONCLUSIONS

This study showed that lung height in AIS patients increased significantly immediately postoperatively whereas lung volume did not change significantly. Thoracic symmetry was improved postoperatively in these patients.