Cardiopulmonary Exercise Testing In Patients With Scoliosis

Part ?:The Influence of Adolescent Idiopathic Scoliosis on Cardiopulmonary FunctionBackground:In patients with adolescent idiopathic scoliosis(AIS),the thoracic spine deformities that could be observed on radiographs included not only scoliosis and vertebral rotation,but also reduction of thoracic kyphosis in the sagittal plane.Studies had found the relation between the severity of thoracic spinal deformity and pulmonary dysfunction.However,there were very few studies on the overall cardiopulmonary function and exercise tolerance of patients with AIS.Objective:To analyze the correlation between radiographic parameters and the results of static pulmonary function testing(PFT)and cardiopulmonary exercise testing(CPET)in patients with AIS.Methods:The clinical data of patients with AIS who were admitted to our hospital between January 2014 and December 2019 were retrospectively collected.Radiographic measurements were performed based on the whole spine and bending X-ray,including coronal and sagittal parameters.PFT and CPET were performed and the results of various functional parameters were collected.Results:A total of 168 patients with AIS(143 female and 25 male)were included,with an average age of 14.2 ± 1.6 years.All patients completed the CPET to exhaustion.When the maximum exercise level was reached,17 patients reported shortness of breath or dyspnea.With increasing magnitude of proximal thoracic curve and the main thoracic curve(within 100°),forced expiratory volume in 1 second(FEV1),forced vital capacity(FVC)and FEV1/FVC(the ratio of FEV1 to FVC)showed a significant decline.There were significant negative correlations between the proximal thoracic curve and main thoracic curve and CPET parameters such as tidal volume(Vt),ventilatory reserve(VR),and oxygen saturation(SpO2).Within a range of 50°,T5-T12 kyphosis were positively correlated with FEV1 and FVC.In addition,patients with double structural thoracic curves had significantly reduced FEV1 and FVC,while the work rate(WR),peak oxygen uptake(VO2peak)and heart rate(HR)at maximum exercise level were not related to the curve pattern.In patients with double structural thoracic curves,Vt were reduced yet respiratory frequency(fR)increased significantly.Patients were divided into two groups according to the physical activity level(PAL).The FEV1 and FVC were significantly reduced in the low PAL group,and the WR and VO2peak also had a significant decline.Among the breathing and circulation parameters,the minute ventilation(VE)and oxygen pulse(O2/pulse)were also significantly reduced in the low PAL group.Conclusion:The severity of restrictive ventilation dysfunction in patients with AIS is related to the magnitude of thoracic spine deformity.In patients with severe thoracic spinal deformities,compensatory breathing patterns appear during exercise.Ventilation reserve and oxygen saturation also decrease at the maximum exercise level.Within a range of main thoracic curve less than 100°,our study did not find a significant correlation between the overall exercise capacity and the severity of spinal deformity.Patients with AIS who maintain moderate to high exercise levels in daily life have higher exercise tolerance than those with low exercise levels.Part ?:The Influence of Congenital Spinal Deformity on Cardiopulmonary FunctionBackground:Congenital spinal deformity is often early-onset and progresses rapidly.Thoracic deformity not only causes decreased thoracic range of motion,but also affects lung development and damages lung function.Routine PFT can detect restrictive ventilation dysfunction,yet it is not possible to systematically measure the exercise tolerance and overall cardiopulmonary functional capacity.Objective:To analyze the correlation between PFT and CPET results and radiographic parameters including spine,rib,thoracic diameters and other measurements in patients with congenital spinal deformity.Methods:The clinical data of patients with congenital spinal deformities who were admitted to our hospital between January 2014 and December 2019 was retrospectively collected.Radiographic measurements included the location of spinal deformity,thoracic scoliosis and kyphosis,rib deformity,thoracic diameter and geometric parameters.PFT and CPET were performed and the results of various functional parameters were collected.Results:A total of 73 patients(47 female and 26 male)with congenital spinal deformity were included,with an average age of 18.9±7.4 years.The average curvature of thoracic scoliosis was 90.0±31.3°,and the average thoracic kyphosis was 46.6±36.2°.Seventy-one patients completed the cardiopulmonary exercise test to exhaustion.At the maximum exercise level,20 patients reported shortness of breath or dyspnea.In the thoracic deformity group,FEV1,FVC,and TLC were significantly reduced and in CPET,VR and SpO2 at maximum exercise level were also decreased.With the increase of thoracic curvature,FEV1,FVC and total lung capacity(TLC)gradually decreased.In CPET,WR,VO2peak and HR decreased significantly in patients with thoracic curve greater than 100°.In terms of lung ventilation and gas exchange,patients with thoracic curve greater than 100° had lower Vt and SpO2 when reaching the maximum exercise level,while fR increased significantly.Thoracic kyphosis had negative correlation with FEV1,FVC,TLC and VO2peak.Patients with complex rib anomaly also had FEV1,FVC,and TLC.In the ventilation indexes of CPET,VE and Vt of the complex rib deformity group were significantly decreased.As for the thoracic geometry parameters,correlation analysis showed that TH/TD and TW/TD were positively correlated with FEV1,FVC and TLC.In CPET,TH/TD,TW/TD are were also positively correlated with WR and VO2peak.The VE,Vt and SpO2 at maximum exercise level also dropped as the TH/TD and TW/TD values decreased.Conclusion:In patients with congenital spinal deformity,the severity of restrictive ventilation dysfunction is related to the magnitude of thoracic scoliosis and kyphosis.For patients with thoracic curvature exceeding 100°,we found that not only the compensated breathing pattern was adopted,but the exercise tolerance also decreased significantly.In addition,the thoracic radial diameter and geometric parameters are significantly related to lung function impairment and exercise tolerance.It is estimated that the ratio of thoracic height to depth>2.3 and width to depth>2.5 may be the threshold of normal peak oxygen uptake at the maximum exercise level.Patients with complex rib abnormality had more severe pulmonary function damage and abnormal ventilation parameters during exercise.Part ?:The Effect of Spinal Surgery on Cardiopulmonary Function in Patients with Adolescent Idiopathic ScoliosisBackground:AIS often causes restrictive ventilation dysfunction.Previous studies have provided clinical evidence of improved lung function in patients treated surgically.However,as a static test,pulmonary function measurement is difficult to reflect changes in overall cardiopulmonary function and exercise tolerance.Objective:Our study aims to analyze the changes of preoperative and postoperative pulmonary function and cardiopulmonary exercise test results in patients with AIS and underwent spinal surgery,and to investigate whether there is a correlation between the improvement of spinal deformity and functional measurements.Methods:We retrospectively collected clinical data of patients with AIS who underwent posterior spinal surgery in our hospital between January 2014 and December 2019.The surgical levels included thoracic spine in all patients.Radiographic measurement was performed on the X-ray of the whole spine.Patients received PFT and CPET pre-operatively and at last follow up.The results of each functional test were collected.Results:A total of 15 patients(12 female and 3 male)with AIS were included.The average age before surgery was 14.1±1.4 years,and the average follow-up was 20.4 month.The correction rates of scoliosis in the upper thoracic,thoracic,and lumbar spine of the patients were 55.3%,74.5%,and 78.5%,respectively.The average height of T1-T12 improved from 23.5cm to 26.3cm.The average FEV1 improved from 2.46 ±0.63L before surgery to 2.69±0.57L at the last follow-up(P=0.004),and the average FVC improved from 2.96±0.76L before surgery to 3.19±0.67L at the last follow-up(P=0.016).In terms of percentage of the predicted value,there is no significant statistical difference.The average preoperative WR was 103.2±27.1 W,and the average at the last follow-up was 108.7±2.2W(P=0.281);the average preoperative VO2peak was 1256.6±280.8 ml/min,and the average at the last follow-up was 1412.4 ± 229.1 ml/min(P=0.086).In terms of the percentage of the predicted value,there is no significant statistical difference.Correlation analysis of changes in functional measurement and radiographic improvements was not found to be statistically significant.Conclusion:In this study,patients with AIS had received posterior spinal surgery.At an average follow-up of 20.4 months,the absolute value of the parameters of pulmonary function test were elevated,while the percentage of the predicted value remained unchanged.CPET results suggest that the peak oxygen intake and work rate at the maximum exercise level also maintained.There is no significant correlation between the improvement of patients radiographic and functional changes.