Analysis of the risk factors for early tether breakage following vertebral body tethering in adolescent idiopathic scoliosis

Introduction

Tether breakage is a common mechanical complication after VBT. When this occurs shortly after surgery, patients may be at higher risk for loss of correction. Aim of this study was to analyze demographic and radiographic parameters that may potentially be risk factors for early tether breakage, as no data are yet available on this topic.

Materials and methods

All skeletally immature patients who underwent VBT and for whom a 1-year follow-up was available were included in the study. Demographic, intraoperative and coronal and sagittal parameters from the preoperative and 1st standing X-rays were collected. Patients were divided in two groups according to the presence or absence of a breakage and the outcomes of interest were compared.

Results

Data from 105 patients were available (age 14.2 ± 1.5, 153 curves). Lumbar curves showed a higher risk of breakage than thoracic ones (71% vs. 29%, P < 0.0001). Overall, preoperative risk factors were a high curve magnitude (MD, mean difference − 4.1°, P = 0.03) and a limited flexibility (MD 8.9%, P = 0.006); postoperative risk factors were a large residual curve (MD − 6.4°, P = 0.0005) and a limited correction (MD 8.4%, P = 0.0005). The same risk factors were identified in thoracic curves, while in lumbar instrumentation only a higher preoperative Cobb angle represented a risk factor for breakage. Age and skeletal maturity did not represent risk factors.

Conclusion

The main preoperative risk factors for early tether breakage after VBT are a high curve magnitude and a limited flexibility. A limited curve correction also represents a risk factor for this complication.

     

Meta-analysis on the efficacy and safety of anterior vertebral body tethering in adolescent idiopathic scoliosis

Purpose

In this meta-analysis, we analyzed the efficacy and safety of anterior vertebral body tethering in patients with adolescent idiopathic scoliosis.

Methods

We performed a literature search and analyzed the following data: baseline characteristics, efficacy measures (corrections of the main thoracic curve, proximal thoracic curve, and thoracolumbar curve, thoracic kyphosis, lumbosacral lordosis, rib hump, lumbar prominence and SRS-22 scores, and complications. Analyses were performed with Cochrane's Review Manager version 5.4.

Results

Twelve studies met the inclusion criteria. Significant corrections of the main thoracic (MD 22.51, 95% CI 12.93 to 32.09) proximal thoracic (MD 10.14°, 95% CI 7.25° to 13.02°), and thoracolumbar curve (MD 12.16, 95% CI 9.14 to 15.18) were found. No statistically significant corrections were observed on the sagittal plane assessed by thoracic kyphosis (MD − 0.60°, 95% CI − 2.45 to 1.26; participants = 622; studies = 4; I2 = 36%) and lumbosacral lordosis (MD 0.19°, 95% CI − 2.16° to 2.54°). Significant corrections were identified for rib hump (MD 5.26°, 95% CI 4.19° to 6.32°) and lumbar prominence (MD 1.20°, 95% CI 0.27° to 2.13°) at final follow-up. Significant improvements of total SRS-22 score (MD − 0.96, 95% CI − 1.10 to − 0.83) were achieved at final follow-up. The most common complication was overcorrection (8.0%) and tether breakage (5.9%), with a reoperation rate of 10.1%.

Conclusions

Anterior vertebral body tethering is effective to reduce the curve in the coronal plane and clinical deformity. Maximum correction is achieved at one year. The method should, however, be optimized to reduce the rate of complications.

     

椎体拴系术治疗脊柱侧凸的研究进展

非融合技术在控制和矫正脊柱畸形的同时可保持脊柱生长能力,近年来在治疗青少年严重脊柱侧凸时得到越来越多的应用.椎体拴系术(vertebral body tethering,VBT)属于非融合技术中的脊柱生长调节非融合术(growth-modulation fusionless surgery)[1],其利用一种由椎体螺钉...     

Difference between radiographically suspected and intraoperatively confirmed tether breakages after vertebral body tethering for idiopathic scoliosis

European Spine Journal - Vertebral body tethering (VBT) has shown promising results but also a high tether breakage rate, which has been reported in up to 48% of patients. Tether breakages can lead...     

Effect of direct vertebral body derotation on the sagittal profile in adolescent idiopathic scoliosis

Purpose  

We sought to clarify the effect of applying derotation maneuvers in the correction of adolescent idiopathic scoliosis (AIS) on the sagittal plane.     

支具治疗对女性青少年特发性脊柱侧凸患者肺功能的影响

目的:观察支具治疗对女性青少年特发性脊柱侧凸(AIS)患者肺功能的影响。方法:2001年2月~2009年12月283例女性AIS患者在我院接受矫形手术治疗,术前检测患者用力肺活量(FVC)、第1秒用力呼气容积(FEV1),记录预计值、实测值及实测值占预计值百分比。根据术前是否曾接受支具治疗分为2组,支具治疗组80例(A组),未接受支具治疗组203例(B组)。分析2组患者术前肺功能参数的差异,同时对A组患者肺功能FVC及FEV1的实测值占预计值百分比(FVC%、FEV1%)与术时年龄、身高、主弯冠状面Cobb角、主侧凸累及节段数、主胸弯矢状面Cobb角、每日支具治疗时间、支具治疗总时长进行多元线性回归分析。结果:A、B组患者FVC预计值分别为3.23±0.40L和3.20±0.40L,FEV1预计值分别为2.76±0.40L和2.73±0.30L,A组与B组比较均无统计学差异(P>0.05);A、B组FVC实测值分别为2.58±0.60L和2.72±0.60L,FEV1实测值分别为2.34±0.50L和2.49±0.50L,A、B组FVC%分别为(80.3±16.5)%和(85.4±16.5)%、FEV1%分别为(85.6±18.4)%和(91.3±16.9)%,A组FEV1实测值、FVC%及FEV1%较B组均明显降低(P<0.05),其中主弯为胸弯患者(173例)明显(P<0.05),而主弯为胸腰弯/腰弯患者(110例)不明显(P>0.05)。A组患者中,胸段侧凸矢状面Cobb角与FVC%、FEV1%呈正相关(P<0.05),支具治疗总时长与FEV1%呈负相关(P<0.05);而术时年龄、身高、主弯冠状面Cobb角、主侧凸累及节段数、每日支具治疗时间(8~23h,平均18.7h)与FVC%及FEV1%均无显著相关性(P>0.05)。结论:支具治疗可使女性青少年特发性胸段脊柱侧凸患者肺功能FVC%及FEV1%下降,支具治疗总时长和胸段侧凸矢状面Cobb角可能是影响患者肺功能FVC%及FEV1%的相关因素。     

青少年特发性脊柱侧凸患者术前肺功能影响因素分析及临床意义

目的 分析影响青少年特发性脊柱侧凸患者术前肺功能的相关影像学参数及其临床意义.方法 回顾性研究2009年7月～2012年8月本院收治的青少年特发性脊柱侧凸患者24例,术前肺功能检查、胸部CT扫描资料完整.分析肺功能结果与站立位全长X线片Cobb角、顶椎偏移、椎体旋转分度（Nash/Moe法）、顶椎肋椎角差值、矢状位T5-12后凸角和胸段累及椎体数目之间相关性.结果 患者年龄平均14.8岁,Cobb角平均52.8°;主弯Cobb角与术前肺活量占预计值百分比、第1秒最大呼气容积占预计值百分比、用力肺活量占预计值百分比、最大通气量占预计值百分比、肺总量占预计值百分比、一氧化碳弥散量占预计值百分比和一氧化碳弥散量呈负相关;顶椎偏移与肺总量占预计值百分比、一氧化碳弥散量占预计值百分比及一氧化碳弥散量呈明显负相关;站立位顶椎凸凹侧肋椎角差值分别与肺总量占预计值百分比、肺总量、一氧化碳弥散量占预计值百分比和一氧化碳弥散量呈负相关;Bending位顶椎凸凹侧肋椎角差值与肺总量、一氧化碳弥散量呈负相关;胸段累及椎体数≥7个组患者50％肺活量时最大呼气流量、75％肺活量时最大呼气流量、最大用力呼气中段流速占预计值百分比、最大通气量占预计值百分比及一氧化碳弥散量占预计值百分比数值,比胸段累及椎体数＜7个组患者有减少（P＜0.05）.结论 术前站立位主弯Cobb角愈大,主弯顶椎偏移增大,站立位以及Bending位顶椎凸凹侧肋椎角差值增加,肺功能下降.近胸弯≥30°组较之＜30°组,胸段累及椎体数≥7个组较之＜7个组,肺功能数值下降.     

Cotrel-Dubousset instrumentation and vertebral rotation in adolescent idiopathic scoliosis

We have studied 34 consecutive patients receiving Cotrel- Dubousset instrumentation for a single and flexible thoracic scoliotic curve, evaluating the rib hump deformity from a single CT scan through the apical vertebra of the curve. Using two measures of rotation we found a mean improvement of 25% in the rotation of the vertebra after operation. Any, usually minor, deterioration occurred in the first six months postoperatively, and there was no significant further deterioration in 19 patients assessed over two years after surgery. Cotrel-Dubousset instrumentation can produce a significant correction of vertebral rotation and of the associated rib hump deformity.     

以胸弯为主的青少年特发性脊柱侧凸对肺功能的影响研究

目的 分析以胸弯为主的青少年特发性脊柱侧凸(adolescent idiopathic scoliosis,AIS)对肺功能的影响.方法 回顾性分析2018年10月至2019年11月在我院确诊并接受治疗的31例AIS病人的临床资料,分析用力肺活量占预测值的百分比(FVC％pred)、第1秒用力呼气容积占预测值的百分比(...     

Evaluation of deformities and pulmonary function in adolescent idiopathic right thoracic scoliosis

Summary Seventy patients with adolescent idiopathic right thoracic scoliosis had full assessment of their pulmonary function using a computerised pulmonary function system. Their mean age at evaluation was 13.8 years. The following measurements were obtained from anteroposterior and lateral standing and antero-posterior supine bending radiographs: lateral curvature, vertebral rotation, kyphosis, maximum sterno-vertebral distance and apical rib-vertebral angles. Using the above measurements, the flexibility of curve, vertebral rotation and rib-vertebral angle asymmetry were calculated. Patients were classified into three groups on the basis of their predicted vital capacity, to determine whether radiological features of deformity can help identify patients with compromised pulmonary function. The mean Cobb angle and vertebral rotation for the 70 patients were 50° (range 35–100°) and 22° (range 1–44°) respectively. The mean flexibility of curve and vertebral rotation were 52% and 49% respectively. Mean thoracic kyphosis was 25%, ranging from -7 to 55%. Of the patients with Cobb angle less than 90%, 71% had vital capacity less than 80% of predicted values, and of these, 18% had marked compromise of vital capacity (less than 60% of predicted values). Mean values of Cobb angle, vertebral rotational flexibility, kyphosis, rib-vertebral angle asymmetry (in standing as well as supine bending radiographs) differed significantly between patients with more than 80% of predicted vital capacity and those with 60% or less of predicted values. Radiological features indicative of better pulmonary function were: rotational flexibility exceeding 55%, rib-vertebral angle asymmetry (standing) less than 25% and kyphosis greater than 15%. Two deformity parameters—that give a better prediction of pulmonary function than the widely used Cobb angle, vertebral rotational flexibility and rib-vertebral angle asymmetry—were identified in this study.     

Platelet function in adolescent idiopathic scoliosis.

Recent studies have reported abnormal platelet morphology and function in patients with adolescent idiopathic scoliosis. These abnormalities include increased platelet size and dense body numbers, abnormal aggregation, thromboxane A2 synthesis, serotonin release to adenosine diphosphate and epinephrine stimulus, and decreased myosin-adenosine-triphosphatase-specific activity. It was postulated that a membrane-specific defect in calcium transport may be partially responsible for the abnormalities found. In response to a suggestion in the literature that platelet screening could be clinically useful in scoliosis evaluation as well as in basic research of its pathophysiology, a study was performed to evaluate platelet morphology, biochemistry, and function in patients with adolescent idiopathic scoliosis. Platelets from nine volunteers with adolescent idiopathic scoliosis were compared with cells from a control group of nine patients. No significant differences in measured platelet parameters were noted between adolescent idiopathic scoliosis patients and control groups. Platelets from both groups demonstrated normal aggregation and release patterns with all agents except for a mild decreased aggregation and secretion response to epinephrine. No significant differences were noted in serotonin or adenine nucleotide levels. No significant ultrastructural differences were noted. Earlier findings of an abnormal aggregation and secretion response to adenosine diphosphate, increased numbers of dense bodies, or increased intracellular calcium could not be confirmed. On the contrary, we found normal, if not slightly decreased, numbers of dense bodies per platelet and calcium levels that were not different from controls.     

The effects of the three-dimensional deformity of adolescent idiopathic scoliosis on pulmonary function

Purpose

Utilizing 2D measurements, previous studies have found that in AIS, increased thoracic Cobb and decreased thoracic kyphosis contribute to pulmonary dysfunction. Recent technology has improved our ability to measure and understand the true 3D deformity in AIS. The purpose of this study was to evaluate which 3D radiographic measures predict pulmonary dysfunction.

Methods

One hundred and sixty-three surgically treated AIS patients with preoperative PFTs (FEV, FVC, TLC) and EOS^® imaging were identified at a single center. Each spine was reconstructed in 3D to obtain the true coronal, sagittal, and apical rotational deformities. These were then correlated with the patient’s preoperative PFT measurements. Regression analysis was performed to determine the relative effect of each radiographic measure.

Results

There were 124 thoracic and 39 lumbar major curves. The range of preoperative thoracic and lumbar 3D coronal angle was 11–115° and 11–98°, respectively. The range of preoperative thoracic 3D kyphosis (T5–T12) and thoracic apical vertebral rotation was ?56 to 44° and 0–29°, respectively. Increasing thoracic 3D Cobb and thoracic vertebral rotation and decreasing thoracic 3D kyphosis most significantly correlated with decreasing pulmonary function, especially FEV. In patients with the largest degree of thoracic deformity (3D Coronal Cobb > 80°, 3D thoracic lordosis >20°, and absolute apical rotation >25°), the majority of patients had moderate to severe pulmonary impairment (≤65 % predicted). 3D thoracic kyphosis was the most consistent predictor of FEV (r ² = 0.087), FVC (r ² = 0.069), and TLC (r ² = 0.098) impairment.

Conclusions

Larger thoracic coronal, sagittal, and axial deformities increase the risk of pulmonary impairment in patients with AIS. Of these, decreasing 3D thoracic kyphosis is the most consistent predictor. This information can guide surgeons in the decision making process for determining which surgical techniques to utilize and which component of the deformity to focus on.

     

仰卧位和俯卧位测量青少年特发性脊柱侧凸患者胸主动脉与椎体毗邻关系的差异

目的　通过术前仰卧位MRI和术中俯卧位O形臂X线机获得青少年特发性脊柱侧凸(AIS)患者横断面影像学资料,探讨2种体位下主胸弯顶椎与胸主动脉的毗邻关系。方法回顾性分析2013年4月—2018年7月美国梅奥医学中心骨科采用后路手术治疗的18例AIS患者资料。患者术前均行仰卧位全脊柱MRI平扫和术中俯卧位脊柱O形臂X线机平扫,将影像资料上传至临床图像显示系统(Qreads 5.10)。选取主胸弯顶椎为测量平面,测量顶椎椎体旋转角度(AVR),主动脉到椎体距离(a线),主动脉到左侧椎弓根置钉点距离(b线),主动脉到椎管垂直距离(c线),主动脉到椎弓根置钉点连线的垂直距离(d线),主动脉椎体角(AVA),左侧椎弓根置钉点和主动脉内侧切线与椎体中轴线平行线间的夹角(∠α),左侧椎弓根置钉点和主动脉中心点连线与椎体中轴线平行线间的夹角(∠β)。采用配对样本t检验比较2种体位下各参数变化,采用Pearson相关分析对数据进行相关性分析。结果俯卧位AVR、c线均大于仰卧位,差异均有统计学意义(P 0.05),平均差值分别为2.71°、2.24 mm。俯卧位与仰卧位AVA平均差值为4.45°,差异有统计学意义(P 0.05);俯卧位AVR、a线、b线、c线、d线、AVA、∠α、∠β与仰卧位相应指标呈正相关;俯卧位∠β与主胸弯Cobb角呈正相关,与俯卧位及仰卧位AVR均呈负相关;俯卧位d线与主胸弯Cobb角呈负相关,与俯卧位及仰卧位AVR呈正相关。结论相较于仰卧位,脊柱侧凸患者俯卧位时顶椎旋转度增大,主动脉到椎管的垂直距离增大,主动脉向椎体右前方移动。     

青少年特发性脊柱侧凸与神经源性脊柱侧凸患者椎体和椎间盘的楔形变及其临床意义

目的:观察青少年特发性脊柱侧凸(adolescent idiopathic scoliosis,AIS)与神经源性脊柱侧凸(neurological scoliosis,NS)患者的椎体和椎间盘的楔形变情况,探讨其临床意义。方法:对35例AIS患者和31例NS患者(继发于Chiari畸形)应用Cobb法测量胸椎和腰椎每个侧凸范围内顶椎及其上、下各两个椎体和相应椎间盘的楔变角,计算其占整个侧凸角度的百分比(楔变率),得出侧凸范围内5个椎体的平均楔变率和4个椎间盘的平均楔变率。应用SPSS10.0统计软件进行统计分析,组间比较采用单因素方差分析。结果:相同病因、相同侧凸部位、相同Cobb角分组情况下,椎体与椎间盘的楔变率存在显著性差异(P0.05)。相同病因、相同侧凸部位,Cobb角60°组的椎体楔变率和椎间盘楔变率与Cobb角≥60°组比较均无显著性差异(P0.05)。相同侧凸部位、相同Cobb角分组,AIS组椎体和椎间盘的楔变率分别与NS组比较均无显著性差异(P0.05)。结论:AIS与NS患者椎体与椎间盘的相对楔形变方式相同,AIS患者的椎体楔形变可能是继发的。在治疗脊柱侧凸时,即便是较小角度的脊柱侧凸,都应该考虑到其存在椎体和椎间盘的楔形变。