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.     

选择性前路胸腰段或腰段融合治疗青少年特发性脊柱侧凸

目的 评价选择性前路胸腰段或腰段融合治疗PUMCⅡd1型(Lenke5型)青少年特发性脊柱侧凸(AIS)的临床效果. 方法回顾性分析35例行选择性前路胸腰段或腰段融合的PUMCⅡd1型(Lenke5型)AIS病例.所有病例均行前路单棒节段性固定融合,随访18～42个月,平均36个月.术前、术后及随访时均摄站立位全脊柱正侧位X线片,对躯干偏移、上下融合椎邻近椎间盘开角、下固定椎的倾斜、冠状面和矢状面Cobb角进行测量分析.测量数据使用SPSS 11.0统计学软件进行分析.结果 胸腰弯或腰弯冠状面Cobb角术前平均45.6°,术后9.7°,末次随访14.4°.胸弯冠状面Cobb角术前平均29.7°,术后17.6°,末次随访20.1°.躯干偏移术前平均14.0 mm,术后14.8 mm,末次随访5.1 mm.下端固定椎(LIV)倾斜术前平均-21.8°,术后-1.5°,末次随访-2.1°.冠状面上端固定椎(UIV)上位椎间盘开角(UIVDA)及LIV下位椎间盘开角(LIVDA)术前分别为0.5°和0.6°,术后为0.9°和4.9°,末次随访时均显著加重,为3.0°和7.8°.矢状面胸段(T5～12)及胸腰段(T10～L2)曲度术后及末次随访时均保持良好.矢状面腰前凸(L1～S1)及固定融合节段Cobb角在术后有所减小,末次随访时均保持良好.所有病例末次随访时均未见假关节形成及其他并发症. 结论 选择性前路胸腰段或腰段融合是治疗PUMCⅡd1型(Lenke 5型)AIS的安全、有效的方法,融合节段上、下椎间盘开角增加及部分病例残余胸弯过大现象需进一步随访评估.     

Anterior instrumentation for adolescent idiopathic scoliosis

Thirty-two patients with adolescent idiopathic scoliosis underwent anterior fusion with rigid single rod (third generation instrumentation) and titanium mesh cages. The mean follow-up was 31 (24-45) months and the mean age was 14.9 years. There were 8 patients with King type I, 10 with type II, 6 with type III, 4 with type IV and 4 with lumbar curves. Titanium mesh cages were used in all the lumbar procedures and at the cranial and caudal ends of the instrumented area in thoracic cases. All the patients were immobilized in an orthosis for 3-6 months postoperatively. Mean preoperative primary coronal Cobb angle of 56 degrees was improved to 8.6 degrees. Average correction rate was 84%. Sagittal balance was restored with a mean thoracic kyphosis of 28 degrees and a mean lumbar lordosis of 38 degrees. Spontaneous secondary curve decompensation did not occur and postoperative thoracolumbar junctional kyphosis was not seen. One case had to be revised due to proximal screw pull out and loss of correction.     

钛网椎间融合器在脊柱侧凸前路矫形矢状面形态维持中作用的初步研究

目的探讨钛网椎间融合器在脊柱侧凸前路矫形中应用的作用、效果及意义。方法对36例胸腰椎或腰椎特发性脊柱侧凸患者行前路手术,在矫形过程中在固定节段的每个椎间隙分别置入单个钛网椎间融合器。其中男性5例,女性31例,年龄14～22岁(平均17岁)。结果患者术前、术后及术后平均随访13个月的侧凸Cobb角分别为56°、15°和18°,胸椎后凸Cobb角分别为30°、33°和37°,腰椎前凸(L1～S1)Cobb角分别为46°、56°和51°。无死亡,无感染,无椎间隙塌陷。术中肉眼下乳糜管损伤1例(予以结扎),术后渗出性胸膜炎1例,两下肢短期皮温不等3例,胸腔积液2例(其中1例行穿刺引流)。结论在脊柱侧凸前路矫形中应用钛网椎间融合器可以达到很好的冠状面和矢状面的矫正,并可有效防止椎间隙的塌陷和防止腰椎后凸的形成。     

Prospective radiographic and clinical outcomes and complications of single solid rod instrumented anterior spinal fusion in adolescent idiopathic scoliosis

STUDY DESIGN: Prospective clinical cases series. OBJECTIVES: To prospectively evaluate outcomes and critically review radiographic results and complications associated with single solid rod anterior spinal fusions in adolescent idiopathic scoliosis with 2-year minimum follow-up (range, 2-6 years). METHODS: Ninety consecutive patients at a single institution with thoracic (n = 43) or thoracolumbar/lumbar (n = 47) adolescent idiopathic scoliosis were treated by one of two surgeons with a similar anterior surgical technique using rib autograft, intradiscal structural (Harms) cages placed below T12, and anterior single solid rod convex compressive instrumentation. The patients were evaluated prospectively with the Scoliosis Research Society outcome instrument and upright radiographs before surgery and minimum 2-year follow-up. RESULTS (RADIOGRAPHIC): The average coronal correction of thoracic curves was from 55 degrees to 29 degrees (47%). The average correction of thoracolumbar/lumbar curves was from 50 degrees to 15 degrees (70%). In the sagittal plane, kyphosis was improved in thoracic fusions from 23 degrees to 30 degrees (T5-T12) and lordosis maintained in thoracolumbar/lumbar fusions at -58 degrees (T12-sacrum). Five patients (5.5%) developed a pseudarthrosis, four with implant failure. Three of five required a posterior fusion for a reoperation rate of 3.3%. The fourth and fifth patients were asymptomatic and appeared fused at the 2-year follow-up, with minimal loss of correction. Common risk factors for pseudarthrosis were smoking (4 of 5), weight >70 kg (4 of 5), and for thoracic pseudarthrosis, hyperkyphosis >40 degrees T5-T12 (2 of 3). RESULTS (CLINICAL OUTCOME): Scoliosis Research Society domain average scores were improved for function, pain, and self-image (P < 0.01). With the Scoliosis Research Society satisfaction domain, 88% responded that they were satisfied with their results and 89% would undergo the same treatment again. Four of five patients with pseudarthrosis did not have statistically significant lower final Scoliosis Research Society scores than those with solid fusions (93 vs. 97, P = 0.18). CONCLUSION: Anterior instrumented fusions for adolescent idiopathic scoliosis using a single solid rod had good radiographic and clinical outcomes. Consideration should be given to alternate techniques in larger adolescents (>70 kg) with thoracic hyperkyphosis (>40 degrees ), and smoking should be avoided. Poor radiographic outcomes did not correlate with final Scoliosis Research Society scores.     

Comparison of push-prone and lateral-bending radiographs for predicting postoperative coronal alignment in thoracolumbar and lumbar scoliotic curves

STUDY DESIGN: A comparative evaluation of supine right and left lateral-bending radiographs and push-prone radiographs in patients with thoracolumbar and lumbar scoliosis to determine postoperative correction of the curve. OBJECTIVES: To determine the difference in the ability of the push-prone radiograph and the supine lateral-bending radiograph to predict postoperative coronal alignment for primary thoracolumbar and lumbar curves managed with an anterior spinal instrumentation and fusion. SUMMARY OF BACKGROUND DATA: Right and left supine side-bending radiographs are the standard means of evaluating curve flexibility before surgery in idiopathic scoliosis. A push-prone radiograph also has been obtained at the authors' institution as a single dynamic radiographic assessment of forced correction of the primary curve and resultant effects on compensatory curves above and below the fusion. METHODS: Preoperative standing, supine right and left lateral-bending, and push-prone radiographs were performed in 40 patients who underwent anterior spinal instrumentation and fusion. Postoperative standing radiographs of the spine were obtained at 3 months after surgery. Measurements on all the radiographs included the coronal Cobb angle, the angle of the lowest instrumented vertebra to the horizontal, the rotation of the lowest instrumented vertebra, and the distance of the midpoint of the lowest instrumented vertebra from the center sacral line. RESULTS: The lateral-bending and the push-prone radiographs predicted less correction of the Cobb angle and the angle of the lowest instrumented vertebra to the horizontal than was achieved after surgery. However, the push-prone radiograph was superior to the lateral-bending radiograph in accurately predicting the postoperative correction of the rotation of the lowest instrumented vertebra as well as the translation of the lowest instrumented vertebra from the center sacral line. CONCLUSIONS: The push-prone and lateral-bending radiographs are similar in predicting less correction of the Cobb angle after anterior spinal surgery. The push-prone radiograph helps in determining the effects that correction of the primary curve has on the curves above and below the level of fusion by better predicting the translational correction of the lowest instrumented vertebra and the rotation of the lowest instrumented vertebra.     

Posterior pedicle screws combined with shortening and release techniques for lumbar and thoracolumbar adolescent idiopathic scoliosis

Objective: To prospectively evaluate the clinical and radiographic effects of posterior surgery with wide posterior shortening release and segmental pedicle screws techniques in a consecutive group of patients with thoracolumbar /lumbar adolescent idiopathic scoliosis. Methods: Between April 2002 and July 2005, 114 patients (86 women and 28 men) were enrolled in this study. There were 72 Lenke type 5, 32 Lenke type 6, and 10 Lenke type 3C curves. Radiographic parameters such as coronal plane Cobb angle; lordosis angle; lowest instrumented vertebrae (LIV) angulation; and the distances from the central sacral vertical line (CSVL) to the LIV, to the apical vertebra and to the C7 plumb line, were analyzed. Complication rates were also recorded during follow‐up. Results: The average coronal correction was from 61° to 13° (78.6%). In the sagittal plane, lumbar lordosis was normalized from 36° with a wide range (23°–67°) to 42° with a normal range (34°–55°). The LIV had 79% correction of coronal angulations. The center sacral line to LIV was improved from 2.3 cm to 0.5 cm, apex to center sacral line from 5.0 cm to 1.6 cm, and CSVL from 2.7 cm to 0.8 cm. A total of 1460 pedicle screws were placed safely, average 9.6 levels (5–14) were fused. The patients were followed up for an average of 30 months (range, 12–50). There was excellent maintenance of correction at final follow‐up. Conclusion: Wide posterior release and segmental pedicle screw instrumentation has excellent radiographic and clinical results with minimal complications.     

Circumferential arthrodesis using PEEK cages at the lumbar spine

Usual interbody cages at the lumbar spine are made of titanium or carbon fiber-polyetheretherketone (PEEK). Pure PEEK cages have more recently been proposed for its lower elasticity modulus. The goal of our study was to investigate a series of patients with circumferential fixation using anterior PEEK cages for degenerative lumbar spine disorders with a specific interest in the local lordosis. Fifty-seven consecutive patients aged 54.6 years (29 to 75) were reviewed. The level of arthrodesis varied from L2L3 to L5S1. The clinical status and the radiologic variations in local lordosis at the level of arthrodesis were measured. Decrease in lordosis at follow-up was tested in a multivariate analysis regarding age, obesity, spinal level, bone graft amount, type of posterior instrumentation, postoperative lordosis increase, and cage height. The average follow-up was 5.7 years (4 to 8). Clinical outcomes were excellent or good in 49 cases. Fusion was definite in 56 cases. Although 47 patients had no change in lordosis after surgery, 10 cases showed lordosis increase (8.2 degrees; 5 to 12). At follow-up, local lordosis decreased in 13 cases (5.6 degrees; 4 to 8). The linear model was significant (P<0.001; R=0.590) showing that loss in lordosis was related with postoperative lordosis increase (P=0.01), cage height (P<0.001), posterior instrumentation rigidity (P=0.026), age (P=0.047), and low level (P=0.013). Lumbar circumferential arthrodesis using PEEK cages provided good clinical results and fusion rate. However, lordosis correction was not maintained at follow-up, especially at lower levels, using high cages, in older patients, and when associated with a rigid primary posterior instrumentation. Regarding the last point, this is likely that the order of the instrumentation (posterior first, then anterior) played a role in the loss of lordosis in case of rigid posterior fixation.     

Treatment of selected neuromuscular patients with posterior instrumentation and arthrodesis ending with lumbar pedicle screw anchorage

STUDY DESIGN: This is a retrospective analysis of 23 patients with severe neuromuscular spinal deformity treated with posterior instrumentation and fusion ending in the lumbar spine. OBJECTIVES: The purposes of this study were to determine the safety and efficacy of stopping posterior instrumentation constructs in the lumbar spine with pedicle screw anchorage. SUMMARY OF BACKGROUND DATA: There are sparse data in the peer-reviewed literature regarding indications and outcomes in patients with neuromuscular disorders for instrumented fusion ended short of the pelvis with transpedicular fixation. METHODS: The average age of patients at surgery was 18.4 years (range, 10-61 years). Additional anterior discectomy and fusion were performed in four patients with large, stiff curves. No patient received anterior instrumentation. Criteria for exclusion of the pelvis from the fusion were less than 15 degrees of pelvic obliquity as a result of a compensatory curve below the major curve(s), the absence of problematic lower extremity contractures, and, often, the potential for ambulation. Process and clinical outcomes and complications were analyzed. RESULTS: Radiographic follow-up was available in 21 patients at an average of 62 months (range, 24-110 months) after surgery. Their average Cobb angle was 71 degrees before surgery, 25 degrees after surgery (64% correction), and 32 degrees at follow-up (54% correction). Their average spinal-pelvic obliquity was 6 degrees before surgery, 5 degrees after surgery, and 6 degrees at follow-up. The average lower instrumented vertebra was lumbar 3.7. Clinical follow-up was available for all 23 patients for an average of 61 months (range, 24-110 months). There were no perioperative deaths, deep wound infections, pseudarthroses, or instrument failures. Outcomes based on responses to questionnaires completed by patient, parent, or caregiver were highly satisfactory in 20 patients (87%), satisfactory in 2 patients (9%) and neither satisfactory nor unsatisfactory in 1 patient (4%). CONCLUSION: Posterior instrumentation and arthrodesis using lumbar lower instrumented vertebra pedicle screw anchorage can be performed safely and effectively, in selected patients patients with scoliosis and minimal pelvic obliquity.     

Do anterior interbody cages have a potential value in comparison to autogenous rib graft in the surgical management of Scheuermann's kyphosis?

BACKGROUND CONTEXT: Previous studies have analyzed the outcome following posterior correction and combined anterior-posterior correction for Scheuermann's kyphosis. Traditionally interbody fusion has been obtained using morselized rib graft. Recently the use of titanium anterior cages has been suggested for interbody use. There are no long-term studies comparing these two techniques. PURPOSE: To investigate the potential value of titanium anterior interbody cages compared with morselized rib graft for anterior interbody fusion in combination with posterior instrumentation, correction, and fusion for Scheuermann's kyphosis. STUDY DESIGN: Nonrandomized comparison of two surgical techniques in matched subjects. PATIENT SAMPLE: Fifteen patients with identical preoperative radiographic and physical variables (age, gender, height, weight, body mass index) were managed with combined anterior release, interbody fusion, posterior instrumentation, correction, and fusion. Group A (n=8) had morselized rib graft inserted into each intervertebral disc space. Group B (n=7) had titanium interbody cages packed with bone graft inserted at each level. The posterior instrumentation extended from T2 to L2 in both groups. OUTCOME MEASURES: Preoperative and postoperative curve morphometry was studied on plain radiographs by two independent observers. The indices studied included Cobb angle, Ferguson's angle, Voutsinas index, sagittal vertical axis (SVA), sacral inclination (SI), and lumbar lordosis (LL). Interbody fusion was assessed at final follow-up. Each patient was reviewed at 3, 6, 12, 24, 48, and 60 months after surgery with standing radiographs. METHODS: Both surgical groups were compared in terms of radiological parameters and complications. Wilcoxon-matched pairs test and Mann-Whitney test were used. RESULTS: The average follow-up for Group A was 70 months and for Group B 66 months. For the whole group, the preoperative median Cobb angle for thoracic kyphosis was 86 degrees , the median Ferguson angle was 50 degrees , Voutsinas index was 28.7, SVA -3.5 centimeters, lumbar lordosis was 66 degrees , and the median sacral inclination angle was 40 degrees . The median postoperative Cobb angle was 42 degrees , Ferguson angle 28.4 degrees , Voutsinas index 13, SVA -4.0 centimeters, and the median sacral inclination angle was 34 degrees . There were significant differences between preoperative and postoperative measurements for all variables (p<.01), indicating that good correction was achieved. At 4-year follow-up, fusion criteria were satisfied in 12 of 15 cases (80%). Three patients had distal junctional kyphosis. There was no significant difference obtained in the final Cobb angle, Ferguson angle, and Voutsinas index when Group A (rib graft) was compared with Group B (titanium cage) Both Group A and B patients retained the postoperative correction achieved with respect to all the radiographic parameters studied. CONCLUSION: We were unable to demonstrate any significant advantage for the use of anterior titanium interbody cages over the use of morselized rib graft in the surgical management of Scheuermann's kyphosis. Given the not inconsiderable cost and the need for posterior chevron osteotomies when interbody cages are used, we have now reverted to our previous practice of using morselized rib graft at each intervertebral level.     

Effect of posterior lumbar interbody fusion on the lumbar sagittal spinal profile

AIM: To determine the effect of different cage geometries and posterior instrumentation on the sagittal spinal profile after monosegmental lumbar interbody fusion. METHOD: The study is based on a retrospective analysis of 119 patients with segmental instability, who were surgically managed by monosegmental PLIF with PEEK-Cages and dorsal instrumentation. RESULTS: At radiographic follow-up after surgery we found a significant improvement of the lumbar sagittal spinal profile, independent of the cage geometry utilised. A marked discrepancy between 0 degrees -standard and 4 degrees -trapezoid implants concerning the radiographic parameters lumbar lordosis, disc height, correction of spondylolisthesis and sacral inclination was not found. With the use of 4 degrees optimised cages in segment L4/5 slightly better results for segmental lordosis were obtained. Reliability of the radiographic evaluation, expressed as intra-observer error, was satisfactory. Cage geometry did not have an effect on the clinical result. By combining interbody fusion with pedicular instrumentation the reposition of slipped vertebra and distraction of the interbody space could more effectively be achieved. Patients without dorsal instrumentation had a higher rate of pseudarthrosis as well as a less satisfactory clinical outcome. CONCLUSION: These results show that normal sagittal alignment after single-level lumbar fusion can be achieved with rectangular and 4 degrees -wedged cages. Although results after utilization of 4 degrees -wedged cages do not significantly differ, these implants offer the surgeon one more sizing variation with which physiological lumbar lordosis may be attained. The combination of intersomatic implants with dorsal instrumentation achieves a more precise realignment and has a lower rate of cage-associated complications. It therefore seems prudent that an interbody fusion for the surgical management of lumbar segmental instability should be combined with pedicular instrumentation.     

Spine behavior caudal to instrumentation in King II and IV curves

This retrospective review of children surgically treated for King Type II or IV curvature of the spine required a minimum lumbar Cobb angle of 40 degrees and a minimum lumbar inclination (the angle formed between a line through the spinous processes of the three most caudal lumbar vertebrae and a line perpendicular to the floor) of 10 degrees. Twenty children had combined anterior thoracolumbar and posterior instrumentations whereas 20 had only posterior instrumentation. Children who had combined surgery had significantly better corrections of their lumbar Cobb angles. They had a mean correction of 43.3 degrees compared with 26.7 degrees in children with posterior instrumentation only. These superior corrections of the lumbar Cobb angles did not result in significantly better improvements in the lumbar inclinations. Patients who had the combined procedures had a mean improvement of 10.1 degrees, whereas patients who had posterior instrumentation only had a mean improvement of 8.0 degrees in lumbar inclination. Instead of having superior corrections of the lumbar inclinations, the combined surgeries resulted in a significant worsening of the angle between the end plates of the last instrumented vertebra and the next most caudal end plate. In patients who had combined surgery this angle averaged 8.4 degrees, whereas in patients who had posterior instrumentation only this angle averaged 4.1 degrees.     

选择性前路手术治疗胸腰段或腰段青少年特发性脊柱侧凸的参数分析

目的 探讨Lenke5、6型青少年特发性脊柱侧凸(AIS)患者选择性前路手术的筛选指标.方法 回顾性分析我院1999年3月至2004年5月期间收治的52例Lenke5、6型AIS患者,随访2～4年(平均34个月),评估术前各相关参数.按术后结果 分成两组:满意组(胸弯减小)A组,不满意组(胸弯加重)B组.结果 A组(n=46)术前胸弯平均33°,术后平均18°,腰弯术前平均49°,术后平均21°.B组(n=6)术前胸弯平均38°,术后平均45°.腰弯术前平均46°,术后平均25°.B组患者中2例由于术后脊柱失平衡,进行了后路翻修术.结论 胸椎柔韧性和患者的成熟度决定了该方案外科手术的效果.在各种结构参数中,(TL/L:T)Cobb比率和胸椎柔韧性,是筛选患者的较好指标.     

The biomechanical effect of postoperative hypolordosis in instrumented lumbar fusion on instrumented and adjacent spinal segments

STUDY DESIGN: Change in lumbar lordosis was measured in patients that had undergone posterolateral lumbar fusions using transpedicular instrumentation. The biomechanical effects of postoperative lumbar malalignment were measured in cadaveric specimens. OBJECTIVES: To determine the extent of postoperative lumbar sagittal malalignment caused by an intraoperative kneeling position with 90 degrees of hip and knee flexion, and to assess its effect on the mechanical loading of the instrumented and adjacent segments. SUMMARY OF BACKGROUND DATA: The importance of maintaining the baseline lumbar lordosis after surgery has been stressed in the literature. However, there are few objective data to evaluate whether postoperative hypolordosis in the instrumented segments can increase the likelihood of junctional breakdown. METHODS: Segmental lordosis was measured on preoperative standing, intraoperative prone, and postoperative standing radiographs. In human cadaveric spines, a lordosis loss of up to 8 degrees was created across L4-S1 using calibrated transpedicular devices. Specimens were tested in extension and under axial loading in the upright posture. RESULTS: In patients who underwent L4-S1 fusions, the lordosis within the fusion decreased by 10 degrees intraoperatively and after surgery. Postoperative lordosis in the proximal (L2-L3 and L3-L4) segments increased by 2 degrees each, as compared with the preoperative measures. Hypolordosis in the instrumented segments increased the load across the posterior transpedicular devices, the posterior shear force, and the lamina strain at the adjacent level. CONCLUSIONS: Hypolordosis in the instrumented segments caused increased loading of the posterior column of the adjacent segments. These biomechanical effects may explain the degenerative changes at the junctional level that have been observed as long-term consequences of lumbar fusion.     

Segmental analysis of the sagittal plane alignment of the normal thoracic and lumbar spines and thoracolumbar junction

Recent advances in spinal instrumentation have brought about a new emphasis on the three-dimensional spinal deformity of scoliosis and especially on the restoration of normal sagittal plane contours. Normal alignment in the coronal and transverse planes is easily defined; however, normal sagittal plane alignment is not so simple. This retrospective study was undertaken to increase the understanding of the normal alignment of the spine in the sagittal plane, with a special emphasis on the thoracolumbar junction. Measurements were made from the lateral radiographs of 102 subjects with clinically and radiographically normal spines. Cobb measurements of the thoracic kyphosis (T3-T12), the thoracolumbar junction (T10-T12 and T12-L2), and the lumbar lordosis (L1-L5) were determined. The spices of the thoracic kyphosis and lumbar lordosis also were determined. Using a computerized digitalizing table, the segmental angulation was determined at each level from T1-2 to L5-S1. In conclusion, there is a wide range of normal sagittal alignment of the thoracic and lumbar spines. When using composite measurements of the combined frontal and sagittal plane deformity of scoliosis, this wide range of sagittal variance should be taken into consideration. Using norms established here for segmental alignment, areas of hypokyphosis and hypolordosis commonly seen in scoliosis can be more objectively evaluated. The thoracolumbar junction is for all practical purposes straight; lumbar lordosis usually starts at L1-2 and gradually increases at each level caudally to the sacrum.     

腰椎退变性侧凸合并椎管狭窄症的外科治疗

目的 探讨腰椎退变性侧凸合并椎管狭窄症的临床特点及外科治疗.方法 回顾性分析1997年1月至2007年1月手术治疗腰椎退变性侧凸合并椎管狭窄症的43例患者,男18例,女25例;年龄51～72岁,平均56.4岁.侧凸Cobb角25°～40°,平均31.8°;腰椎前凸-40.5°～70°,平均-20.9°.采用后正中切口,"责任狭窄节段"椎板减压,切除突出的"责任椎间盘",扩大狭窄的神经根管.应用平移、去旋转结合凹侧撑开、凸侧加压技术,矫正侧凸.28个椎间隙应用融合器融合,9个椎间隙应用自体髂骨融合.其余节段行后外侧融合.结果 术后随访1～10年,平均4.9年,采用JOA 29分标准进行评定.末次随访侧凸Cobb角5°～10°,矫正度数12°～30°,矫正率58.8%.腰椎前凸角矫正为-12°～17.3°,平均12.3°.所有患者均获得骨性融合,术前JOA评分11分,末次随访为25分,优良率为90.1%.未发现螺钉断裂、松动,无断棒现象.1例术后10d出现皮肤浅表感染,应用敏感抗生素而治愈;1例术后脑脊液漏,经抬高床尾,口服醋氮酰胺治愈.2枚钛合金cage移位,无不适而未处理.结论 腰椎退变性侧凸合并椎管狭窄症的外科治疗较为棘手,手术以解决"责任节段"为重点,融合固定是保证治疗效果的前提.     

Mesh cages in idiopathic scoliosis in adolescents.

Since 1995, titanium mesh cages have been used in the thoracolumbar and lumbar spine for instrumented anterior spinal fusions in adolescents with idiopathic scoliosis. One hundred thirty patients had 451 fusion levels with cages. Radiographic results show acceptable coronal correction with maintained or improved thoracolumbar and lumbar lordotic sagittal alignment. The pseudarthrosis rate has been 3% per patient (four of 130 patients) and 0.08% per fusion level with a cage (four of 451 levels). The authors think that the use of titanium mesh cages anteriorly with single or dual rod anterior instrumentation systems provide for adequate lordotic sagittal alignment and an acceptable pseudarthrosis rate.     

Lumbar lordosis restoration following single-level instrumented fusion comparing 4 commonly used techniques

A major sequelae of lumbar fusion is acceleration of adjacent-level degeneration due to decreased lumbar lordosis. We evaluated the effectiveness of 4 common fusion techniques in restoring lordosis: instrumented posterolateral fusion, translumbar interbody fusion, anteroposterior fusion with posterior instrumentation, and anterior interbody fusion with lordotic threaded (LT) cages (Medtronic Sofamor Danek, Memphis, Tennessee). Radiographs were measured preoperatively, immediately postoperatively, and a minimum of 6 months postoperatively. Parameters measured included anterior and posterior disk space height, lumbar lordosis from L3 to S1, and surgical level lordosis.No significant difference in demographics existed among the 4 groups. All preoperative parameters were similar among the 4 groups. Lumbar lordosis at final follow-up showed no difference between the anteroposterior fusion with posterior instrumentation, translumbar interbody fusion, and LT cage groups, although the posterolateral fusion group showed a significant loss of lordosis (-10°) (P<.001). Immediately postoperatively and at follow-up, the LT cage group had a significantly greater amount of lordosis and showed maintenance of anterior and posterior disk space height postoperatively compared with the other groups. Instrumented posterolateral fusion produces a greater loss of lordosis compared with anteroposterior fusion with posterior instrumentation, translumbar interbody fusion, and LT cages. Maintenance of lordosis and anterior and posterior disk space height is significantly better with anterior interbody fusion with LT cages.     

Thoracic kyphoscoliosis resembling neurofibromatosis: a case report focusing on subfascial instrumentation.

BACKGROUND CONTEXT: The management of early-onset progressive scoliosis is controversial. PURPOSE: To describe the unusual surgical management of a young female with an early-onset progressive, short, angular kyphoscoliosis resembling neurofibromatosis. STUDY DESIGN: A case report reviewing the treatment of an unusual occurrence of kyphoscoliosis. METHODS: After compliant Milwaukee brace wear had failed to stop deformity progression, surgical management including segmental anterior and posterior T5-T10 arthrodesis, and posterior T3-L4 subfascial rod instrumentation was performed at age 4 years and 6 months. After 10 rod lengthenings, segmental anterior T10 to L3 arthrodesis and posterior T3-L4 instrumentation and arthrodesis were done at age 11 years and 5 months. RESULTS: From preoperative to 3-year postoperative definitive surgery, her T3 to L4 instrumented spine length increased by 9.5 cm; 4 cm after the initial surgery, 3 cm between the initial surgery and the definitive surgery and 2.5 cm after the definitive surgery. From preoperative to latest follow-up, her thoracic scoliosis was reduced from 89 to 31 degrees, her thoracolumbar compensatory scoliosis from 59 to 37 degrees and her kyphosis from 70 to 17 degrees. CONCLUSIONS: The combination of early definitive anterior and posterior major curve arthrodesis with a subfascial rod lengthening program to control the remainder of the thoracolumbar spine was a satisfactory solution for this unusual case of early-onset, progressive, short, angular kyphoscoliosis.     

Selective ventral derotation spondylodesis in idiopathic thoracic scoliosis: a prospective study

AIM: Radiometric curve analysis of instrumented primary and spontaneous secondary curve correction after anterior correction and fusion of idiopathic thoracic scoliosis. METHOD: Sixty-four patients with idiopathic thoracic scoliosis were prospectively evaluated. All patients were operated either with the Zielke-VDS or with a primary stable double rod instrumentation with selective fusion of the thoracic curve from end-to end-vertebra. Follow-up averaged 29 months (24 - 52 months). RESULTS: The Cobb angle of the primary curve averaged 63.2 degrees preoperatively and was corrected to 21.4 degrees postoperatively with an average loss of correction of 5.3 degrees (58 % final curve correction). Apical thoracic vertebral rotation was corrected by 48 %. The secondary lumbar curve measured 38.2 degrees preoperatively (72 % correction on the bending films) and was spontaneously corrected by 57 % to 16.4 degrees without significant loss of correction in the final follow-up. Apical vertebral rotation averaged 11.3 degrees in the lumbar curve and was corrected spontaneously by 24 % to 8.6 degrees without significant loss of correction. Lumbar apex vertebra deviation showed no significant reduction. There was no case of lumbar curve decompensation in either frontal or sagittal plane. Implant related complications were observed in 7 patients (rod breakage), but no pseudarthrosis occurred. There were no neurological complications noted. CONCLUSION: Selective anterior correction and fusion in idiopathic thoracic scoliosis enables a satisfactory correction of both primary and lumbar secondary curves. The advantage of selective anterior correction and fusion of thoracic scoliosis is the short fusion length, better derotation and satisfactory correction of the secondary lumbar curve. The disadvantages of single threaded rod techniques in terms of lack of primary stability and a kyphogenic effect have been eliminated by the development of a primary stable, small size double rod instrumentation.