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。     

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.     

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.

     

Pulmonary function after thoracoplasty in adolescent idiopathic scoliosis

The current study evaluated sequential pulmonary function tests prospectively at a minimum of 2 years after thoracoplasty in adolescent patients with idiopathic scoliosis. Twenty patients were divided into two groups: Group I (n=12) was comprised of patients who had posterior instrumented fusion with external thoracoplasty, and Group II (n=8) was comprised of patients who in addition to a posterior instrumented fusion, had an anterior release and fusion via video-assisted thoracoscopic surgery (n=4) or open thoracotomy (n=4) because of rigid severity. Forced vital capacity and forced expiratory volume in 1 second of percent predicted values in Group I declined 9% at 3 months postoperatively and returned to the preoperative baseline at 1 year. However, forced vital capacity and forced expiratory volume in 1 second of percent predicted values in Group II declined 11% to 18% postoperatively and did not return to the preoperative baseline at 2 years. Posterior instrumented fusion with thoracoplasty in adolescent patients with idiopathic scoliosis significantly decreased pulmonary function at 3 months, but returned to the preoperative baseline at 1 year. The addition of an anterior releasing procedure resulted in poorer pulmonary function, which did not return to the preoperative baseline by the 2-year followup.     

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。     

Prospective pulmonary function evaluation following open thoracotomy for anterior spinal fusion in adolescent idiopathic scoliosis

STUDY DESIGN: Prospective study. OBJECTIVES: To prospectively evaluate sequential pulmonary function tests (PFTs) at a minimum 2-year follow-up after an open anterior spinal fusion (ASF) with instrumentation for thoracic AIS. SUMMARY OF BACKGROUND DATA: Anterior spinal fusion with instrumentation is currently undergoing evaluation as an alternative to posterior spinal fusion (PSF) for thoracic adolescent idiopathic scoliosis (AIS). However, the effect of an open thoracotomy on pulmonary function in these patients is unknown. METHODS: Fifty-one patients with thoracic AIS with an average age of 15+0 (range 11+2 to 20+5) had PFTs consisting of volume (FVC), flow (FEV-1), and total lung capacity (TLC). Parameters were obtained preoperatively, and at 3 months, 1 year, and a minimum 2-year follow-up. All patients had a single or double open thoracotomy with the diaphragm kept intact. Fusion levels ranged from T4 (most proximal) to L1 (most distal). The average preoperative thoracic coronal Cobb measurement was 53 degrees (range 38 degrees to 80 degrees ), and the average postoperative coronal measurement was 24 degrees (range 7 degrees to 49 degrees ). The average preoperative thoracic sagittal kyphosis (T5-T12) averaged 22 degrees (range 10 degrees to 58 degrees ), and the average postoperative sagittal kyphosis measured 29 degrees (range 7 degrees to 67 degrees ). RESULTS: There was a significant decline (P< or =0.05) in PFT absolute values (L) of 19%-FVC, 15%-FEV-1, and 11%-TLC at 3 months postoperatively with subsequent improvement and no statistical difference between preoperative and 2-year postoperative values. When evaluating percent predicted values, there was a statistical decline (P< or =0.05) at 3 months postoperatively averaging 19% FVC, 14% FEV-1, and 12% TLC. These values returned to within 94% to 96% of baseline by the 2-year follow-up visit, but were still statistically less than the preoperative values (P相似文献   

Analysis of pulmonary function and axis rotation in adolescent and young adult idiopathic scoliosis patients treated with Cotrel-Dubousset instrumentation.

Forty-eight patients with idiopathic scoliosis underwent posterior spinal fusion with Cotrel-Dubousset instrumentation (CDI). Each patient was given preoperative and postoperative pulmonary function tests (PFTs). Pulmonary volume improved a mean 0.40 L (16%), and pulmonary flow improved a mean 0.33 L (15%). Differences between preoperative and postoperative PFT values were shown to be statistically significant and correlated well with coronal side-bending correction. Twenty patients had preoperative and postoperative CT scans through the apical vertebra. Vertebral rotation was assessed on CT scan by the method of Aaro and Dahlborn (1,2). At the apex, the mean percentage improvements in the longitudinal axis rotation relative to the midline (16%) and to the sagittal plane (10%), the rib hump index (8%), and the kyphosis-lordosis index (0%) were minimal. Radiographically, the 66% mean improvement in apical vertebral translation was more substantial and consistent than the 10% mean improvement in apical vertebral rotation. Therefore, at the apex the CDI "derotation maneuver" may be more of a "translational maneuver."     

马方及类马方综合征脊柱侧凸与青少年特发性脊柱侧凸患者肺功能障碍的差异性比较

目的:比较马方和类马方综合征脊柱侧凸(Marfan syndrome and Marfanoid scoliosis,MMS)患者与青少年特发性脊柱侧凸(adolescent idiopathic scoliosis,AIS)患者肺功能的差异及影响因素。方法:1999年9月~2013年4月我院收治的以胸弯(冠状面)为主的马方及类马方综合征脊柱侧凸患者共85例,其中年龄为11~19岁且临床资料完整的患者共40例(MMS组),男14例,女26例;收集患者术前肺功能指标,包括第1秒最大呼气容积(FEV1)、用力肺活量(FVC)、最大用力呼气峰流量(PEF),数值采用实测值占预计值的百分比,分析肺功能指标与年龄、冠状面Cobb角、胸后凸Cobb角、胸弯柔韧度之间的关系。并与同期住院行脊柱侧凸矫形内固定术的相匹配的80例AIS患者(AIS组)的术前肺功能参数进行比较。采用曼-惠特尼U检验比较两组间的差异,并用Pearson相关性分析对两组患者肺功能指标与患者年龄及相关脊柱侧凸指标进行相关性分析。结果:MMS组患者中肺功能处于中、重度损害的比例(11/40)显著高于AIS组(5/80)(P0.05)。MMS组患者FEV1、FVC均明显小于AIS组患者(P0.05);PEF两组间差异无统计学意义。MMS组患者FEV1、FVC与冠状面Cobb角呈显著性负相关(r=-0.444、-0.524,P0.05);FEV1、FVC、PEF与年龄之间呈正显著性相关(r=0.363,0.326,0.348,P0.05);FVC与胸弯冠状面柔韧度之间呈显著性正相关(r=0.321,P0.05);FEV1、FVC与胸椎后凸角均无显著相关性。AIS组患者FEV1、FVC、PEF等指标与冠状面Cobb角呈显著性负相关(r=-0.338、-0.293、-0.253,P0.05);FEV1、PEF与年龄之间呈显著性正相关(r=0.286、0.341,P0.05);FEV1与胸后凸Cobb角之间呈显著性正相关(r=0.238,P0.05)。两组患者肺功能指标与相关指标间的相关性存在差异。结论:MMS患者肺功能损害较AIS患者严重,其肺功能主要受胸弯冠状面Cobb角、年龄共同影响。