Prognosis of spontaneous thoracic curve correction after the selective anterior fusion of thoracolumbar/lumbar (Lenke 5C) curves in idiopathic scoliosis

Background contextPrognosis of minor lumbar curve correction after selective thoracic fusion in idiopathic scoliosis is well defined. However, the prognosis of minor thoracic curve after isolated anterior fusion of the major lumbar curve has not been well described.PurposeTo define the prognosis of spontaneous thoracic curve correction after selective anterior fusion of the lumbar/thoracolumbar curve in idiopathic scoliosis.Study designA retrospective cohort study on the prognosis of the minor curve after selective anterior correction and fusion of the lumbar/thoracolumbar curve in idiopathic scoliosis.Patient sampleIdiopathic lumbar scoliosis patients treated with anterior spinal fusion.Outcome measuresThe Scoliosis Research Society 22 questionnaire was used as an outcome measure at the final follow-up.MethodsTwenty-eight patients were included in this study. Four patients were male, 24 patients were female, and average age at the time of surgery was 16 years. Mean follow-up was 48 months. According to the Lenke Classification, 22 patients were 5CN, 5 were 5C?, and 1 was 5C+. All operations were performed in the same institution. Standing long posterior-anterior and lateral radiographs were taken just before surgery, 1 week after surgery, and at final follow-up.ResultsThe mean preoperative Cobb angle of the lumbar (major) curve was 53° (standard deviation [SD]=8.6) and that of the thoracic (minor) curve was 38.4° (SD=6.24). The lumbar and thoracic curves were corrected to 10° (SD=7.6) and 25° (SD=8.3) postoperatively and measured 17° (SD=10.6) and 27° (SD=7.7), respectively, at the last follow-up. There was a significant difference between the preoperative and postoperative measurements of the minor curves (p<.05). However, there was no significant difference between the early postoperative and the final follow-up measurements (p>.05). Regarding the overall sagittal balance, there was no significant difference between preoperative, early, and late postoperative measurements (p>.05).ConclusionsSelective anterior fusion of the major thoracolumbar/lumbar curve was an effective method for the treatment of Lenke Type 5C curves. Minor thoracic curves did not progress after selective fusion of thoracolumbar/lumbar curves in minimum 2-year follow-up.     

Predictability of the spontaneous lumbar curve correction after selective thoracic fusion in idiopathic scoliosis

In this study we tried to achieve a better understanding of the biodynamic mechanism of balance in the scoliotic spine. Therefore we focused on the pre- and postoperative spine of patients with idiopathic scoliosis with a primary thoracic curve and a secondary lumbar curve. Several studies showed that the lumbar curve spontaneously corrects and improves after selective thoracic fusion. We try to understand and describe this spontaneous compensatory lumbar curve correction after selective thoracic correction and fusion. We performed a retrospective examination of pre- and postoperative radiographs of the spine of 38 patients with idiopathic scoliosis King type II and III. Frontal Cobb angles of the thoracic and lumbar curves were assessed on pre- and postoperative antero-posterior and side bending radiographs. We determined the postoperative corrections of the thoracic and lumbar curves. Relative (%) corrections and correlations of the postoperative corrections were calculated. The group was divided in three subgroups, depending on lumbar curve modifier, according to Lenkes classification system. The calculations were done for the whole group as for each subgroup. As expected, significant correlations were present between the relative correction of the main thoracic and the lumbar curve (mean R = 0.590; P = 0.001). The relation between relative thoracic and lumbar correction decreased with the lumbar modifier type. This study shows a highly significant correlation between the relative corrections of the main thoracic curve and the lumbar curve after selective thoracic fusion in idiopathic scoliosis. This correlation depends on lumbar curve modifier type. This new classification system seems to be of great predictable value for the spontaneous correction of the lumbar curve. Depending on the curve-type, a different technique for predicting the outcome should be used. The lumbar curve correction does not occur throughout the whole lumbar curve. Most correction is achieved in the upper part of the curve. The distal lumbar curve seems to be more rigid and less important in the spontaneous curve correction.     

青少年特发性脊柱侧凸主胸弯融合后未融合上胸弯的变化及其与肩部平衡的关系

【摘要】 目的：探讨青少年特发性脊柱侧凸（AIS）患者主胸弯融合后未融合上胸弯的变化及其与肩部平衡的关系。方法：回顾性分析2008年1月~2010年12月在我院接受手术治疗的AIS患者,选取年龄10～18岁,Lenke分型为Lenke 1、2、3、4型,右胸弯且Cobb角＜80°,采用后路椎弓根螺钉系统固定矫形,固定融合上端椎在T4或T4以下,随访时间2年以上的患者,排除翻修手术和截骨手术患者。术前根据Lenke分型判断上胸弯是否为结构性,分成结构性上胸弯组和非结构性上胸弯组,统计比较两组术前、术后3个月和末次随访时外观肩部平衡以及影像学各项参数的变化。结果：共有62例患者纳入本研究,平均年龄14.4岁,随访时间24~62个月,平均36.4个月,其中结构性上胸弯组17例,非结构性上胸弯组45例。两组患者术后上胸弯均能自发性矫正,末次随访时,上胸弯Cobb角平均由27.9°减小至19.4°,T1倾斜角由-0.21°增加至4.7°,第一肋倾斜角（FRT）由0.4°增加至3.7°,锁骨角（CA）由-1.5°增加至0.8°,双肩高度差（CSH）由-13.0mm增加至5.2mm,改变均有统计学意义（P=0.000）。Pearson相关性分析显示,T1倾斜角的改变（术后T1倾斜角-术前T1倾斜角）与CSH变化（术后CSH-术前CSH）有较强相关性（r=0.624,P=0.000）,术后主胸弯的矫正率和FRT与CSH变化为中等程度相关（r=0.437,0.345,P=0.007,0.006）,术前主胸弯Cobb角与CSH变化为弱相关（r=0.262,P=0.040）。上胸弯Cobb角及柔韧性、主胸弯柔韧性、T1倾斜角等参数与CSH变化无统计学相关性。结论：AIS患者结构性与非结构性上胸弯在主胸弯矫正以后均有自发性矫正现象,但T1倾斜角、第一肋倾斜角和双肩高度差均会增加。右胸弯患者左肩被抬高的程度与T1倾斜角增加的程度、主胸弯的矫正率及术后第一肋倾斜角相关。     

前路Moss Miami器械矫形治疗特发性胸腰段或腰段脊柱侧凸

目的:评价MossMiami前路矫形系统对特发性胸腰段或腰段脊柱侧凸的手术效果。方法:对21例胸腰段或腰段特发性脊柱侧凸患者经前路胸腹联合入路行MossMiami矫形内固定,自体肋骨椎间植骨融合术。测量手术前后Cobb角以及躯干侧方位移。结果:Cobb角术前平均53°,术后平均5°,矫正率为90%。上方代偿性胸椎侧凸术前平均17°,术后矫正至平均5°。下方代偿性腰骶椎侧凸术前平均43°,术后自发矫正至19°。随访12~24个月,Cobb角平均丢失19.7°,胸腰段(T11~L1)术前平均前凸0.3°(0~4°),术后平均后凸3°(0~5°)。躯干侧方位移从术前平均26mm矫正至术后5mm。1例术后出现一侧下肢交感神经切断症状,2例术后并发气胸。无感染、截瘫及内固定失败等并发症发生。结论:MossMiami前路器械具有操作简单和低切迹的优点。棒的预弯、去旋转矫形、正确选择螺钉置入部位和椎间植骨可防止固定节段后凸畸形的形成。对Risser征小于4度的患者应密切观察上方代偿性胸椎侧凸进展情况。     

King Ⅱ型特发性脊柱侧凸的手术治疗

目的：探讨King Ⅱ型特发性脊柱侧凸患者三维矫形融合节段的选择。方法：1997年7月～2002年6月手术矫形治疗King Ⅱ型特发性脊柱侧凸患者79例，平均年龄14．3岁，其中King Ⅱ A型28例，均行选择性胸椎融合，平均融合椎体8．5个；King ⅡB型51例，均固定融合胸椎与腰椎，平均融合椎体11．8个。结果：术后平均随访35个月(12～57个月)，King ⅡA型胸弯矫正率为56％，King ⅡB型的胸弯矫正率为67％，腰弯矫正率为60％。共有5例躯干失平衡并发症，其余患者均获得较好的躯干平衡和矫形效果。结论：KingII型特发性脊柱侧凸进行选择性胸椎融合是可行的，但应慎重。     

胸弯为主的青少年特发性脊柱侧凸后路矫形术后肩部失平衡的危险因素分析

【摘要】 目的：观察以胸弯为主的青少年特发性脊柱侧凸（AIS）患者后路矫形术后肩部失平衡的发生情况,探讨其危险因素。方法：回顾性分析96例以胸弯为主的AIS患者的临床资料,Lenke分型为Lenke 1、2、3、4型,均为右胸弯且Cobb角＜80°。男15例,女81例;年龄10～18岁,平均14.5岁。均采用后路椎弓根螺钉系统固定矫形,随访22～68个月,平均42.2个月。根据术后肩部平衡情况,将患者分为肩部平衡组和肩部失平衡组,分析比较两组患者的临床资料和影像学特点。结果：肩部失平衡患者17例,发生率为17.7%。单变量分析和Logistic回归分析的结果发现与术后肩部失平衡相关的3个独立因素为：术前锁骨角（OR=1.873,P=0.018）、术前主胸弯Cobb角（OR=2.222,P=0.028）和术后主胸弯Cobb角（OR=0.483,P=0.039）。其中锁骨角和术前主胸弯Cobb角为危险因素,术前锁骨角的正值越大,主胸弯角度越大,术后肩部失平衡的危险性越大;术后主胸弯Cobb角为保护因素,术后主胸弯残余角度较大时,能相对避免肩部失平衡的发生。结论：术前锁骨角为正性倾斜、主胸弯角度较大和术后主胸弯残余角度过小可能是AIS患者主胸弯矫正后肩部失平衡的独立危险因素。     

Surgical assessment of the proximal thoracic curve in adolescent idiopathic scoliosis

Existing predictive signs as available in current literature may miss potential proximal thoracic (PT) curve deterioration and shoulder imbalance, following selective main thoracic (MT) curve correction in adolescent idiopathic scoliosis (AIS). The present study is an attempt to evaluate and complement these signs, through a retrospective study of 56 AIS patients who underwent correction and fusion from 1986 till 2003 with follow-up 4–16 years. Forty-nine had fusion of MT curve, 7 of MT and PT. Cotrel–Dubousset instrumentation in 45, Luque in 12. Preoperative data: MT 50° (40°–80°), PT 25° (0°–50°), shoulder elevation from −4 cm (right) to 2 cm (left), clavicle angle from −14° to 5°, PT bending correction from 0 to 100% and T1 tilt from −15° to 14°. We introduced the first rib index (FRI), i.e., the difference between the diameter of right and left first rib arch as a percentage of the sum of both diameters, averaging from −22.7 to 14.3%. (Minus signs refer to or predict right, while positive left shoulder elevation.) Evaluation included all predictive parameters as related principally to postoperative left shoulder elevation ≥1 cm, patient satisfaction and surgeon fulfillment. Postoperative correction MT curve 53% (23–83%) and PT 35% (0–100%). One progressive paraplegic started 40 min following normal wake-up test. Immediate decompression, full recovery. Three cases with wound infection recovered after late removal of instrumentation. Loss of correction ≥10° in five. Fifteen had postoperative persisting left shoulder elevation ≥1 cm. Seven of these expressed dissatisfaction. Statistically FRI proved valuable predictive factor always in combination with previously described signs. We concluded that a postoperative left shoulder elevation ≥2 cm is a potential cause of dissatisfaction and may be prevented with thorough validation of all predictive signs, principally the FRI. Part of this paper was presented at the 62nd annual meeting of the Hellenique Orthop. Society (October 2006) and received the 1st award for best clinical paper.     

Short anterior instrumented fusion and posterior convex non-instrumented fusion of hemivertebra for congenital scoliosis in very young children

A variety of treatments has been described in the literature for the treatment of HV. We report the results of early surgical anterior instrumented fusion with partial preservation of the HV and posterior non-instrumented fusion in the treatment of progressive congenital scoliosis in children below the age of six. Between 1996 and 2006, 31 consecutive patients with 33 lateral HV and progressive scoliosis underwent short segment fusions. Mean age at surgery was 2 years and 10 months. Mean follow-up period was 6.1 years. The major scoliotic curve improved from 41° preoperatively to 17° on follow-up. Preoperative segmental Cobb angle averaging 39° was corrected to 15° after surgery, being 15° at the last follow-up (62% of improvement). Compensatory cranial and caudal curves corrected by 47 and 45%, respectively. The angle of segmental kyphosis averaged 16° before surgery, 11° after surgery, and 11° at follow-up. There were two wound infections requiring surgical debridment, one intraoperative fracture of the vertebral body and one case lost correction due to implant failure. All went on to stable bony union. There were no neurological complications. Early diagnosis and early and aggressive surgical treatment are mandatory for a successful treatment of congenital scoliosis and prevention of the development of secondary compensatory deformities. Anterior instrumentation is a safe and effective technique capable of transmitting a high amount of convex compression allowing short segment fusion, which is of great importance in the growing spine. Study conducted at the Great Ormond Street Hospital for Children and the Royal National Orthopaedic Hospital, Stanmore, London, UK.     

Segmental pedicle screw instrumentation in idiopathic thoracolumbar and lumbar scoliosis

The role of posterior correction and fusion in thoracolumbar and lumbar scoliosis as well as pedicle screw instrumentation in scoliosis surgery are matters of debate. Our hypothesis was that in lumbar and thoracolumbar scoliosis, segmental pedicle screw instrumentation is safe and enables a good frontal and sagittal plane correction with a fusion length comparable to anterior instrumentation. In a prospective clinical trial, 12 consecutive patients with idiopathic thoracolumbar or lumbar scolioses of between 40° and 60° Cobb angle underwent segmental pedicle screw instrumentation. Minimum follow-up was 4 years (range 48– 60 months). Fusion length was defined according to the rules for Zielke instrumentation, normally ranging between the end vertebrae of the major curve. Radiometric analysis included coronal and sagittal plane correction. Additionally, the accuracy of pedicle screw placement was measured by use of postoperative computed tomographic scans. Major curve correction averaged 64.6%, with a loss of correction of 3°. The tilt angle was corrected by 67.0%, the compensatory thoracic curve corrected spontaneously according to the flexibility on the preoperative bending films, and led to a satisfactory frontal balance in all cases. Average fusion length was the same as that of the major curve. Pathological thoracolumbar kyphosis was completely corrected in all but one case. One patient required surgical revision with extension of the fusion to the midthoracic spine due to a painful junctional kyphosis. Eighty-five of 104 screws were graded “within the pedicle”, 10 screws had penetrated laterally, 5 screws bilaterally and 4 screws medially. No neurological complications were noted. In conclusion, despite the limited number of patients, this study shows that segmental pedicle screw instrumentation is a safe and effective procedure in the surgical correction of both frontal and sagittal plane deformity in thoracolumbar and lumbar scoliosis of less than 60°, with a short fusion length, comparable to anterior fusion techniques, and minimal loss of correction. Received: 23 September 1999 Revised: 20 January 2000 Accepted: 26 January 2000     

Radiographic evaluation of selective anterior thoracolumbar or lumbar fusion for adolescent idiopathic scoliosis

According to Lenke classification of adolescent idiopathic scoliosis (AIS), patients with type 5 curve in which the structural major curve is thoracolumbar or lumbar curve with nonstructural proximal thoracic and main thoracic curves, could be surgically treated with selective anterior thoracolumbar or lumbar (TL/L) fusion. This study retrospectively analyzed the radiographies of selective anterior TL/L fusion in 35 cases of AIS with Lenke type 5 curve. Segmental fixation with a single rigid rod through anterior thoracoabdominal approach was applied in all patients. Measurements of scoliosis curve in preoperative, immediate postoperative and follow-up radiographies were analyzed. The average follow up time was 36 months (24-42 months). The average preoperative Cobb angle of the TL/L curve was 45.6 degrees and improved into 9.7 degrees immediate postoperatively, with 79.7% curve correction. In addition, the minor thoracic curve decreased from 29.7 degrees preoperatively to 17.6 degrees postoperatively, with a spontaneous correction of 41.5%. During the follow-up, a loss of 4.6 degrees correction was found and the average Cobb angle of TL/L increased to 14.4 degrees . Also, the minor thoracic curve increased to average 20.1 degrees with a loss of 2.4 degrees correction. Trunk shift deteriorated slightly immediate postoperatively and improved at the follow-up. The lowest instrumented vertebra (LIV) tilt was improved significantly and maintained its results at the follow-up. During the follow-up, the coronal disc angle immediately above the upper instrumented vertebra (UIVDA) and below the LIV (LIVDA) aggravated, while the sagittal contours of T5-T12 and T10-L2 were well maintained. The lumbar lordosis of L1-S1 and the sagittal Cobb angle of the instrumented segments were reduced slightly postoperatively and at the follow-up. There were no major complications or pseudarthrosis. The outcomes of this study show that selective anterior thoracolumbar or lumbar fusion with solid rod instrumentation is effective for surgical correction of AIS with Lenke type 5 curve. The TL/L curve, minor thoracic curve, and LIV title can be improved significantly, with good maintenance of sagittal contour. However, the UIVDA and LIVDA aggravate postoperatively when the trunk rebalances itself during follow-up. The degeneration of LIV disc warrants longer-term follow-up.     

Anterior lumbar instrumentation improves correction of severe lumbar Lenke C curves in double major idiopathic scoliosis

Fifteen skeletally immature patients with double major adolescent idiopathic scoliosis with large lumbar curves and notable L4 and L5 coronal plane obliquity were retrospectively studied. Seven patients who underwent anterior release and fusion of the lumbar curve with segmental anterior instrumentation and subsequent posterior instrumentation ending at L3 were compared with eight patients treated with anterior release and fusion without anterior instrumentation followed by posterior instrumentation to L3 or L4. At 4.5 years follow-up (range 2.5-7 years), curve correction, coronal balance and fusion rate were not statistically different between the two groups; however, the group with anterior instrumentation had improved coronal plane, near normalangulation in the distal unfused segment compared with the group without anterior instrumentation. In cases involving severe lumbar curvatures in the context of double major scoliosis, when as a first stage anterior release is chosen, the addition of instrumentation appears to restore normal coronal alignment of the distal unfused lumbar segment, and may in certain cases save a level compared with traditional fusions to L4.     

Lenke 5C型脊柱侧凸后路选择性矫形术下端融合椎影像学改变对冠状面平衡的影响

【摘要】 目的：探讨下端融合椎（lowest instrumented vertebra,LIV）相关影像学指标对Lenke 5C型特发性脊柱侧凸（adolescent idiopathic scoliosis,AIS）患者术后冠状面平衡的影响。方法：本研究包括30例行后路选择性融合的Lenke 5C型AIS患者,所有患者于术前、术后即刻及末次随访时拍摄站立前后位像及术前仰卧位拍摄左右Bending像。对术前、术后和末次随访时的冠状面平衡与LIV相关影像学指标（LIV偏移、LIV旋转、LIV倾斜度、LIV尾侧椎间盘开角）进行分析。结果：所有患者平均随访33个月（24~50个月）,其中LIV为L3者20例,L4者10例。30例Lenke 5C型AIS患者术前冠状面胸腰弯/腰弯Cobb角平均为49.8°±5.1°,术前冠状面胸弯Cobb角平均为25.6°±7.1°。相关性检验发现以下3个指标与术后即刻冠状面平衡（coronal trunk balance,CTB）有显著相关性：（1）术前CTB（r=0.69,r2=0.48,P<0.01）;（2）术前LIV倾斜度（r=0.63,r2=0.40,P<0.01）;（3）术后即刻LIV倾斜度（r=0.60,r2=0.36,P<0.01）。在末次随访时,不管是术前还是术后的LIV相关影像学指标均与末次随访时CTB无显著相关（P>0.05）。结论：对行后路选择性融合术的Lenke 5C型AIS患者而言,术前冠状面平衡与否及术前LIV倾斜度大小对预测术后即刻冠状面平衡有重要的作用。术前LIV倾斜大于25°的患者容易发生术后即刻冠状面失平衡。然而,LIV倾斜度对Lenke 5C型AIS患者术后冠状面平衡无显著影响。     

Mid-term effects of Cotrel-Dubousset instrumentation on the configuration of the spine and the thoracic cage in thoracic idiopathic scoliosis

Summary The effect of Cotrel-Dubousset instrumentation (CDI) on the three-dimensional spinal deformity in 24 consecutive patients with idiopathic scoliosis was investigated by posteroanterior and lateral radiographs and by computed tomography preoperatively, postoperatively, and at a mean follow-up of 3.2 years (range 2.0–5.3 years). At follow-up the mean Cobb angle was decreased by 73%, and the translation of the apical vertebra was significantly decreased by 33%. The sagittal contour was significantly improved with thoracic kyphosis T5–12 increased by 46% (6.9°) and lumbar lordosis L1–5 increased by 28% (10.3°) at follow-up. The sagittal diameter was significantly improved by 5 mm at follow-up. Although the vertebral rotation and the size of rib hump was improved postoperatively, this was followed by significant loss of correction, and at follow-up the vertebral rotation and the size of rib hump were not significantly better than preoperatively. The study indicates that while CDI improves the coronal and sagittal plane deformity permanently, the effect on vertetebral rotation and the rib hump deteriorates with time.     

Rip hump correction and rotation of the lumbar spine after selective thoracic fusion

In this study a series of 32 patients with idiopathic scoliosis, managed with selective thoracic fusion, was reviewed. Classified according to King and instrumented with the H-frame, the patients were evaluated for curve correction, rib hump correction and postoperative shift in lumbar rotation. Age and follow-up averaged 19.4 and 2.4 years, respectively. The 32 patients had an average primary and lumbar curve correction of, respectively, 66% (6.0% correction loss) and 53% (3.4% correction loss). The respective values for postoperative rib hump correction and shift in apical lumbar rotation averaged 8° and 9.4° in type II King curves, 4.4° and 3.5° in type III and 11° and-5° in Type IV. Significant differences were noted between the curve types in rib hump correction and shift in lumbar rotation. The study showed that en bloc postoperative rotation of the compensatory lumbar segment, directed towards the rib hump, positively influences rib hump correction. This en bloc rotation of the unfused lumbar segments is induced by the correcting forces applied by the instrumentation. The unfused lumbar spine of a patient with a King type II curve shows a larger lumbar rotation shift and subsequent rib hump correction than that of a patient with a King type III curve. Together with factors such as lateral angulation, rib-vertebra angles and structural limitations, the rotational dynamics of the unfused lumbar spine seem to form an important component in the understanding and surgical management of scoliosis.     

Characteristics of the pelvic axial rotation in adolescent idiopathic scoliosis: a comparison between major thoracic curve and major thoracolumbar/lumbar curve

Background contextAs the biomechanical foundation of the spine, the pelvis was found to display rotation in the transverse plane in adolescent idiopathic scoliosis (AIS). However, the possible factors influencing the pelvic axial rotation (PAR) and its mechanism in patients with AIS remain unclear.PurposeTo characterize the PAR in AIS patients with right major thoracic (MT) or major left thoracolumbar/lumbar (TL/L) curve and to explore the associated influencing factors and probable mechanism of compensation by analyzing the association between PAR and other spinal radiographic parameters.Study designRetrospective study.Patient sampleAll patients with the primary diagnosis of AIS from January 2008 to November 2009 were retrieved from our scoliosis database.Outcome measuresAge, Cobb angle, and apex rotation of the main curve and the compensatory curve, curve flexibility, and PAR.MethodsOne-hundred thirty-two patients with right MT (14.7±1.8 years, 48±6.9°) and 83 patients with left major TL/L (14.7±1.5 years, 46±6.6°) were retrospectively reviewed. On standing full-spine posteroanterior radiographs, the PAR was quantified by the left/right hemi-pelvis width ratio (L/R ratio); then the subjects in both MT and major TL/L groups were divided into two subgroups: L/R ratio ≤1 (pelvis rotated to the right, R-PAR group); and L/R ratio >1 (pelvis rotated to the left, L-PAR group). Comparisons of all variables were performed between the L- and R-PAR subgroups; correlation and regression analysis were carried out to identify the influencing factors of PAR.ResultsThe majority of the MT and major TL/L patients (75.8% vs. 60.2%) displayed right pelvic rotation, which was in the same direction as the thoracic curve. The incidence of R-PAR was greater in the MT patients than the major TL/L ones (p=.016). Lumbar flexibility in MT patients with R-PAR was greater than in MT patients with L-PAR (0.96±0.27 vs. 0.81±0.33, p=.038), which was contrary to the findings in the major TL/L patients (L-PAR>R-PAR, 0.79±0.15 vs. 0.70±0.22, p=.024). In the MT patients with R-PAR, the L/R ratio showed significant positive correlations with the lumbar Cobb angle (r=0.424) as well as with the apex rotation (r=0.488), which was further identified as an influencing factor (R=0.418) of the PAR. Significant positive correlations between L/R ratio and thoracic apex rotation (r=0.361) also were detected.ConclusionThe majority of AIS patients with right MT or left major TL/L curves were found to have PAR to the right, in the same direction as the thoracic curve. The lumbar flexibility and apex rotation significantly influenced the PAR direction and magnitude. Moreover, the pelvis might be involved in compensation for the MT deformity through its connection with the lumbar spine.     

The results of anterior fusion and Cotrel-Dubousset-Hopf instrumentation in idiopathic scoliosis

Anterior instrumentation for the correction of scoliotic curves has recently been gaining in popularity. The problems of high mortality and morbidity that were associated with the employment of anterior instrumentation in the first years it was used have now been overcome. Efforts are now being concentrated on increasing the correction rates in the frontal plane and decreasing the kyphotic effect in the sagittal plane. The anterior Cotrel-Dubousset-Hopf (CDH) system is a recently developed instrumentation that has been claimed to decrease the kyphotic effect through the use of double rods. This study aimed to investigate the impact of the anterior CDH system on idiopathic scoliotic curves in frontal and sagittal planes. To this end, 26 idiopathic scoliosis patients treated with the CDH system were followed for a mean period of 32.8 ± 5.3 months. In the frontal plane, Cobb angles of major and secondary curves were measured, and postoperative and final correction rates determined. In the sagittal plane, sagittal contours of both the instrumented region and the thoracic and lumbar regions were measured, and their preoperative, postoperative and final control values were determined. In addition to clinical examination, lateral trunk shift (LT), shift of head (SH) and shift of stable vertebra (SS) were measured in vertebral units (VU), on the preoperative and postoperative radiographs in order to evaluate the effect of the system on trunk balance. It was established that in patients with single flexible thoracolumbar and lumbar curves and those with rigid thoracic curves, the correction rates obtained in the frontal plane were respectively 79.4 ± 14.8%, 68.0 ± 9.4% and 61.5 ± 8.0%, with statistical significance. Their final corrections at the last control were 76.3 ± 17.4%, 56.9 ± 9.1% and 52.3 ± 8.3%, respectively. Although the corrections in the lumbar rigid curves were relatively low, they were still statistically significant. Taking all the patients together, the mean preoperative Cobb angle of the major curves of 67.2°± 20.2° improved to a mean of 28.6°± 21.0°, which was a statistically significant difference (P < 0.05), giving a mean correction rate of 61.2 ± 20.3%. The mean correction loss of major curves in the frontal plane in all patients was 6.0°± 3.8° and the mean final correction rate was 52.6 ± 23.2%. In the sagittal plane, there was a favorable kyphotic effect on the thoracic region of patients with hypokyphosis and lordosis pattern, whilst in patients with kyphotic pattern, this effect was minimal. In patients with a single flexible lumbar curve, kyphotic effect was not observed except in two patients. In these two patients, it was thought that excessive compression force may have been used. As to the patients with a rigid lumbar curve, there was a slight decrease in lumbar lordosis. No postoperative complaints were made about imbalance, and the mean overall correction in LT values was 60.1 ± 21.7%. While preoperatively, the SH and SS values of all patients were over 0.5 VU, postoperatively, 12 patients (46.2%) were completely balanced (SH = 0 VU, SS = 0 VU) and 8 patients (30.8%) were balanced (0 VU < SH and SS < 0.5 VU). The remaining six patients, whose balance values were corrected with statistical significance but were still over 0.5 VU, were found to be the ones with rigid lumbar curves. Implant failure and systemic complications were not noted in the follow-up period. In view of these findings, it was determined that CDH instrumentation achieves significant correction rates in the frontal and sagittal planes, particularly in single flexible lumbar, thoracolumbar and thoracic rigid curves. It was found that the kyphotic effect was minimized with a double rod system. Significant clinical and radiological corrections were achieved in balance values, without any imbalance and decompensation problems. Received: 27 April 1999 Revised: 13 April 2000 Accepted: 2 May 2000     

The segmental effect of Cotrel-Dubousset instrumentation on vertebral rotation,rib hump and the thoracic cage in idiopathic scoliosis

The segmental effect of Cotrel-Dubousset instrumentation (CDI) on the spine and thoracic cage was investigated in 38 patients with adolescent idiopathic scoliosis by preoperative and postoperative postero-anterior and lateral radiographs and computed tomography from T1 to S1. Mean Cobb angle decreased by 67%. The T5–T12 kyphosis in the hypokyphotic patients increased on average by 8.4° (P<0.001). Average preoperative as well as postoperative maximal vertebral rotation was located at the apex level, and was reduced from 19.0° to 14.3° (P<0.001). All vertebrae between the upper and lower instrumented vertebrae were significantly derotated. Average derotation for the apical zone was 4.8° (P<0.001), for the upper instrumented zone it was 2.5° (P<0.01), and for the lower instrumented zone it was 2.6° (P<0.01). Vertebral derotation was significantly higher in the apical zone than in the upper and lower instrumented zones. The apical rib hump index (RHi) decreased by 38% (P<0.001) and the cumulative RHi for the five apical levels decreased by 34% (P<0.001). The RHi for the two levels above and below the instrumentation each decreased by 20% (n.s.). No significant increase in sagittal or transverse rib cage diameter at any level was observed. The translation in the coronal plane of the apical vertebra of major right thoracic curves improved significantly (P<0.001). The preoperative flexibility index of the major curve correlated positively (r=0.47) with derotation at the apex level (P<0.01). However, no correlation was found between flexibility index and reduction of RHi at the apex level. Vertebral derotation did not correlate with reduction in RHi at any level. The study shows that CDI results in a postoperative three-dimensional improvement of the spine and a limited improvement of the thoracic cage, with no tendency towards a worsened deformity at any level within or outside the instrumentation.     

Comparison of anterior and posterior double-rod instrumentation for thoracic idiopathic scoliosis: results of 141 patients

Ventral derotation spondylodesis, according to Zielke, achieves good results in operative treatment of idiopathic thoracic scolioses. Corrections of scoliotic major and secondary curve as well as derotation of the spine are reliably performed. The high rate of rod fractures with subsequent correction loss as well as a proportionate kyphogenic effect represents a problem. By keeping to the correcting principle, anterior double-rod instrumentation (Halm-Zielke Instrumentation) is to be stable in a similar way as posterior double-rod systems. Thus, it is done to facilitate brace-free postoperative care and to prevent excessive kyphotic pattern of the spine. In this prospective study, we retrospectively collected data. We performed radiological follow-up of two groups of patients with idiopathic thoracic scoliosis (King II, III and IV) undergoing an operation with posterior approach (USS instrumentation, posterior group, n=104) in 1997 and 1998 or being corrected with an anterior fusion (Halm-Zielke instrumentation, anterior group, n=37) between 2000 and 2001. Mean age of all patients for operation was 15±4 years. Follow-up was performed after 4±2 years on average. Preoperative measurements of the major and secondary curve, the lateral profile, rotation and frontal balance (C7 to S1) did not show any significant differences apart from a more severe scoliotic curve in the lumbar spine for the anterior group with appropriately higher lumbar rotation. During follow-up we noticed similar corrections of the thoracic major and lumbar curve in both groups ranging from 49 to 56%. In case of hypokyphotic (T4–T12≤20°) scoliosis a kyphogenic effect on the thoracic spine was achieved with both surgical methods. Hyperkyphotic (T4–T12≥40°) scolioses were flattened by posterior spinal fusion; the effect of anterior spinal fusion was not significant. Correction of thoracic and lumbar rotation in the anterior group by 37 or 30% was more significant than in the posterior group by 27 or 20%. There was no impact of anterior technique on the balance of the spine whereas the latter shifted by an average of 7 mm to the left in the posterior group. The number of fused segments was significantly smaller in the anterior group with 7±1 vertebral bodies (posterior, 11±1 vertebral bodies). Rates of complication were identical with 11 or 12% in both groups during follow-up. Anterior and posterior double-rod instrumentations result in comparable corrections for idiopathic thoracic scoliosis of the major and secondary curve. In case of posterior technique, however, four vertebral bodies less were integrated in spondylodesis on average. Balance of the spine did not change after anterior spondylodesis; however, it declined by using the posterior technique. Augmentation of the anterior threaded rod combined with a solid second rod significantly decreases the rate of implant breakages and reliably reduces consecutive correction losses.     

肋骨结构性支撑植骨在青少年特发性脊柱侧凸前路矫形融合术中的应用

目的:评价肋骨结构性支撑植骨在青少年特发性脊柱侧凸(AIS)前路矫形融合术中的应用效果。方法:回顾性分析术后随访时间超过1年的AIS病例35例,男4例,女31例;年龄12～17.5岁,平均14.6岁。侧凸类型包括PUMCⅠa型1例,Ⅰb型6例,Ⅰc型3例,Ⅱc1型1例,Ⅱd1型24例。采用前路三维矫形手术,融合3～7节椎体,平均4.4节。内固定器械包括CDH21例、Isola12例、TSRH1例、Moss Miami1例。全部病例均采用自体肋骨结构性支撑植骨。术前、术后及随访时摄脊柱X线片,测量冠状面及矢状面Cobb角,并观察植骨融合情况,有无假关节形成及螺钉松动、断钉、断棒等内置物并发症。结果:随访12～75个月,平均29个月,融合弯冠状面矫形率术后平均为76.5%,其中21例随访超过2年者末次随访时矫形丢失平均4.2°;固定融合节段冠状面矫形率术后平均为93.6%,随访超过2年者末次随访时丢失平均1.7°;固定融合节段矢状面Cobb角术前与术后比较无显著性差异(P=0.086),随访超过2年者末次随访时矫形丢失平均2.3°。13例胸腰段后凸患者术前后凸平均8.3°,术后矫正为前凸5.6°,1年随访时保持前凸4.2°。全部病例末次随访时均未见假关节形成和内置物并发症。结论:在AIS前路矫形融合手术中采用肋骨结构性支撑植骨融合率高,能获得并维持良好的冠状面及矢状面矫形,是一种可靠、有效的植骨方法。     

Combined anterior and posterior instrumentation in severe and rigid idiopathic scoliosis

A prospective clinical and radiographic evaluation of 33 consecutive patients with severe and rigid idiopathic scoliosis (average Cobb angle 93°, flexibility on bending films 23%) were treated with combined anterior and posterior instrumentation with a minimum follow-up of 2 years. All patients underwent anterior release and VDS-Zielke Instrumentation of the primary curve. In highly rigid scoliosis, this was preceded by a posterior release. Finally, posterior correction and fusion with a multiple hook and pedicle screw construct was performed. Thirty patients were operated in one stage, three patients in two stages. Preoperative curves ranged from 80 to 122° Cobb angle. Frontal plane correction of the primary curve averaged 67% with an average loss of correction of 2°. The apical vertebral rotation of the primary curve was corrected by 49%. In all but three patients, sagittal alignment was restored. There were no neurological complications, deep wound infections or pseudarthrosis. Combined anterior and posterior instrumentation is safe and enables an effective three-dimensional curve correction in severe and rigid idiopathic scoliosis.