Is There a Correlation Between Cobb Angle and Pulmonary Function Tests at 2-year Follow-up in Patients With Severe Spinal Deformity Treated by Posterior Vertebral Column Resection?

Abstract

Study design: A retrospective study. Objective: The aim was to evaluate the relationships of Cobb angle and pulmonary function tests (PFTs) changes in severe spinal deformity and underwent posterior vertebral column resection (PVCR). Summary of Background Data: No previous study focused on the correlation of deformity correction and PFTs changes in patients with cobb angle >90 degrees. Methods: PFTs values [forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), and percent-predicted values FVC%, FEV1%] were evaluated preoperative and at 2 years after PVCR. FVC% <80% were defined as restrictive ventilation dysfunction (RVD), the severity of RVD were divided into mild (FEV1% ≥70%), moderate (70% > FEV1% ≥50%) and severe (FEV1% <50%). The relationships among PFTs values improvements and all possible impact factors (mainly correction cobb angle) collected in this study were analyzed. PFTs data were compared among the 3 RVD subgroups (mild vs. moderate vs. severe) and between residual >30 versus <30 degrees. Results: A total of 53 cases (28 male/25 female, mean ages 18.9 Y) underwent PVCR in one center from 2004 to 2016 were enrolled cobb angle. When 2 years after PVCR, average PFTs values showed significant improvements. PFTs values changes showed no correlation with correction rate and correction angle. The only significant impact factor in this study for FVC, FVC%, FEV1 improvements was preoperative FVC% and the only impact factor for FEV1% improvement was preoperative FEV1%, the relationships were negative. In accordance with the regression analysis, PFTs values improvements among the 3 RVD subgroups from high to low was severe>moderate>mild. However, patients with residual cobb angle <30 degrees had less PFTs values improvements than patients with residual cobb angle >30 degrees. Conclusions: Two years after PVCR, PFTs values were significantly improved. There is no linear correlation between cobb angle change and PFTs values improvements. Lower preoperative FVC% and FEV1% indicate more PFTs values improvements at 2 years post-PVCR. Level of Evidence: Level III.

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

“…By contrast, all patients who underwent only low-grade osteotomy rather than 3-column osteotomy in this study had not presented the shortening of thoracic spine. As a result, the mean FVC increased from 1.59 to 1.95 L (increase of 0.36 L) in the study of Zhang et al, 16 which was less than the value of our study (increase of 0.55 L). Inspiringly, for patients with SRSS, it is necessary to maintain the original length of thoracic spine and correct thoracic deformity as much as possible to obtain the greatest improvement in lung function and volume.…”

“…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 blood loss of 1490.8 mL and mean operation time of 269.8 mins in the patients of our study were significantly less than the values of the reported study by Zhang et al 16 In addition, no serious irreversible neurological complications and deep infection occurred after surgery. Taken together, preoperative HPT combined with posterior multilevel Ponte osteotomy is a more feasible and safer operative strategy compared with 1-stage PVCR surgery.…”

“…The study of the correlation among the correction of severe spinal deformity, improvement of pulmonary function, and change of lung volume is relatively rare. Zhang et al 16 reported that there was no correlation between the change in Cobb angle change and the improvements in PFT values before and after PVCR. Interestingly, in this study, the variation of MTC had significant positive correlations 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) before HPT and after surgery, and we also found that the variation of MTC showed positive correlation with the variation of Vin (r = 0.425, P = .015) before HPT and after surgery.…”

“…PVCR is an effective method to treat SRSS, but related complication is relatively high, 9,14,15 and the results of reported studies, which discussed the effect of PVCR on pulmonary function, are still controversial. 4,16 We therefore proposed the strategy of using preoperative HPT combined with posterior lowgrade osteotomy to treat SRSS and explore the influence of it on patients' pulmonary function and lung volume. The results revealed that the patients' pulmonary function and lung volume were significantly improved after HPT and at the final follow-up, respectively, and there were significant correlations among the variations of MTC, PFT outcomes, and Vin before HPT and after surgery.…”

“…PVCR is often used for the treatment of patients with SRSS. Zhang et al 16 reported 53 patients with SRSS treated by PVCR with a mean blood loss of 3549 mL and a mean operation time of 600 minutes and found that the FVC, FVC%, and FEV1 of patients were significantly improved from 1.59 L, 49.2%, and 1.44 L to 1.95 L, 55.8%, and 1.77 L, respectively at the 2-year follow-up. However, previous researches shown that PVCR potentially presented significant risks, such as neurological deficits and pulmonary compromise.…”