Frontal Cobb Angle Research Articles

Spine to pelvis “T-Construct” using magnetic controlled growing rods in non-walkers neuromuscular early-onset scoliosis: a preliminary study

BackgroundsMagnetic controlled growing rods (MCGRs) have been proven to be effective in controlling early onset neuromuscular scoliosis but no study has evaluated the combination with a sacro-bi-iliac construct. The aim of our study is to report surgical management of early onset non-walkers neuromuscular scoliosis correction using MCGRs associated with a sacro-bi-iliac “T-construct” and its mid-term outcomes. Our hypothesis was that this set-up provided well correction of the pelvic obliquity and that this correction was maintained over time. MethodsA retrospective single-center study was conducted including all consecutive neuromuscular early onset scoliosis who underwent spinopelvic fixation using “T-construct” with two MCGRS. Four millimeters lengthening was performed every 4 months during outpatient clinics sessions. All children had a low-dose biplanar stereoradiography in EOS-Chair at pre/postoperative phase, each outpatient clinic appointment and last follow-up. ResultsEighteen patients were included and 17 analyzed at the last follow-up. The mean age at surgery was 9.5 (range from 5 to 12 years), the mean follow-up was 4,7 years (range from 2.5 to 6.6 years) and 8 patients had a Risser stage above four. The global complication rate was 35% (N = 6/17 patients) including three medical and three mechanical complications related to “T-construct”, while the reoperation rate was 18% (N = 2 patients for wound debridement and one for iterative pelvic fixation). Cobb angle and pelvic obliquity were significantly improved by surgery (mean correction was 33.2 ° (55%) and 11 ° (77%) respectively; p < 0.001). At the last follow-up, we noted a loss of frontal Cobb angle correction (p < 0.01) whereas we did not observe any significant loss of pelvic obliquity (p > 0.9). ConclusionsAlthough the global complication rate was 35% (half of which are mechanical complications), the treatment combining pelvic T-construct and MCGRs provides satisfactory correction of pelvic obliquity correction, good maintenance in the medium term and may be a procedure to consider for the surgical treatment of early onset neuromuscular scoliosis. Level of evidenceIV; Retrospective cohort prognostic study

Efficacy of polyester bands placed under the transverse vertebral process for the correction of adolescent idiopathic scoliosis : A case series of 105 patients with a minimum of 24 months follow-up.

To report an original technique for the surgical correction of adolescent idiopathic scoliosis (AIS) based on hybrid construct using polyester bands placed under the thoracic transverse processes. We reviewed 105 patients operated between 2013 to 2017 for AIS with a minimum of 2years follow-up. Clinical and radiological data, including 2D measurements of scoliosis parameters preoperatively, and at 3- and 24-months postoperatively were analyzed. Radiological analysis was performed by two independent observers using KEOPS (Smaio, Lyon-France, CE 2014) database. Mean age was 14.6 ± 2years. Mean follow-up was 23.7 ± 1.2months. Most curves were classified as Lenke-1 (78%). The average number of vertebra involved in the construct was 10.9 ± 1.3 (range 7-13). A mean of 12.8 implants were used per construct (mean implant density 0.59). The number of subtransverse bands placed averaged 3 (range 1-5 bands). The mean frontal Cobb angle decreased from 57.9 to 21.2° (p < 0.05) postoperatively. The average T4-T12 kyphosis increased from 20.2°to 32.4° (p < 0.05) postoperatively and no loss of correction was observed at 2years follow-up. We encountered one case of transverse process fracture intraoperativley. No neurological complications were observed. In the postoperative period, 4 cases were diagnosed with distal junctional failure, three of which required an extension of the construct, while the fourth case was treated by bracing. The use of subtransverse band is an efficient and safe method for the surgical correction of AIS. This technique incorporates technical ease (minimal risk of neurological injury), provides good frontal correction and restores thoracic kyphosis. Results are maintained over a two-year period.

A Predictive Model of Progression for Adolescent Idiopathic Scoliosis Based on 3D Spine Parameters at First Visit.

Prospective cohort study. The objective of the present study was to design a model of AIS progression to predict Cobb angle at full skeletal maturity, based on curve type, skeletal maturation, and 3D spine parameters available at first visit. Adolescent idiopathic scoliosis (AIS) is a three-dimensional (3D) spinal deformity that affects 1% of adolescents. Curve severity is assessed using the Cobb angle. Prediction of scoliosis progression remains challenging for the treating physician and is currently based on curve type, severity, and maturity. The objective of this study was to develop a predictive model of final Cobb angle, based on 3D spine parameters at first visit, to optimize treatment. A prospective cohort of AIS patients at first orthopedic visit was enrolled between 2006 and 2010, all with 3D reconstructions. Measurements of five types of descriptors were obtained: angle of plane of maximum curvature, Cobb angles, 3D wedging, rotation, and torsion. A general linear model analysis with backward selection was done with final Cobb angle (either just before surgery or at skeletal maturity) as outcome and 3D spine parameters and clinical parameters as predictors. Of 195 participants, 172 (88%) were analyzed; average age at presentation was 12.5 ± 1.3 years and mean follow-up to outcome, 3.2 years. The final model includes significant predictors: initial skeletal maturation, curve type, frontal Cobb angle, angle of plane of maximal curvature, and 3D disk wedging (T3-T4, T8-T9) and achieved a determination coefficient (R) = 0.643. Positive and negative predictive values to identify a curve of 35 degrees are 79% and 94%. This study developed a predictive model of spinal curve progression in scoliosis based on first-visit information. The model will help the treating physician to initiate appropriate treatment at first visit. 3.

3-Year follow-up of a single magnetically controlled growing rod with contralateral gliding system and apical control for early onset scoliosis

Study designTwo-center retrospective cohort study.ObjectiveThe aim of this study is to investigate the clinical effectiveness and safety of the MCGR hybrid in terms of spinal growth, 3D correction, balance, and complications.Summary of background dataThe magnetic-controlled growing-rod (MCGR) growth instrumentation method has gained popularity for early onset scoliosis (EOS) treatment in the past years due to the non-invasiveness of the subsequent interval elongation procedures. To improve 3D correction and reduce the costs, we combined a single concave MCGR with a sliding rod on the convex side to control the apex.MethodsA retrospective cohort study of 18 EOS children with an average 3-year follow-up (range 2.0–3.7) from two European spine centers treated with the single MCGR hybrid concept; 14 primary and 4 conversion cases. The primary and conversion cases were both evaluated preoperatively, postoperatively, 1 year, 2 years, and last follow-up.ResultsMean age was 9.9 (SD ± 2.9 years). The average frontal Cobb angle was reduced from mean 65° to 30° postoperatively, and had increased to 37° at latest follow-up. Rotation of the apical vertebra improved from mean 27° to 20° postoperatively which was partially lost to 23°. Kyphosis and lordosis both increased by an average of 5° during the time of follow-up. Spinal balance was improved. The post-implantation T1–S1 spine growth rate averaged 10 mm/year at last follow-up. There were 13 implant-related complications in 6 out of 18 patients. No screw pull-outs and nor surgical site infections were registered.ConclusionsThis is the first medium-term results of a single MCGR hybrid construct. Maintenance of correction and growth are reasonable, and the complication rate is relatively low as compared to bilateral MCGR application.Level of evidenceIII.

Is There Still a Place for Convex Hemiepiphysiodesis in Congenital Scoliosis in Young Children? A Long-Term Follow-up.

Study Design:Retrospective cohort.Objectives:To evaluate the long-term effect of convex growth arrest (CGA) on coronal deformity correction in congenital scoliosis.Methods:Twenty-two patients with congenital scoliosis operated by 1-staged double approach hemiephysiodesis by bone grafting of the convex side without instrumentation are included. Eighteen curves had an isolated hemivertebra while 4 curves had congenital bar. Subgroup analysis was performed according to age at surgery (3 years cutoff), type of malformation (hemivertebra vs congenital bar), and severity of curve (35° cutoff).Results:Patients’ mean age at surgery was 3 years (range 0.5-8 years), with a mean frontal Cobb angle of 40.59°. Mean follow-up is 10.7 years (range 5.5-25 years). Overall results showed mean frontal Cobb angle reduction of 35.47% (40.59° to 27.41°). Detailed analysis showed that 15 curves had a mean correction of 51.8%, 5 stabilized and 2 had a mean aggravation of 25.11%. Subgroup analysis revealed that patients operated ≤3 years of age had mean cobb angle correction of 43.1% versus 21.49% in patients operated >3 years (P = .140). Mean correction of 44.5% was gained in curves with isolated hemivertebra compared with 1.3% in curves with congenital bar (P = .004). A 58.17% mean correction was reached in curves ≤35° versus 23.68% in curves >35° (P = .032).Conclusions:A limited convex hemiepiphysiodesis still has a place in congenital scoliosis care when it is performed in patients ≤3 years old, with curves ≤35°, and with isolated hemivertebra. It spares patients the risks of vertebral resection and instrumentation, while fusing the same number of levels.

Three-dimensional reconstructions of the rib cage in adolescent idiopathic scoliosis: What determines gibbosity?

Introduction Subjects with adolescent idiopathic scoliosis (AIS) often seek treatment with the aim of correcting the gibbosity of the rib cage. Current surgical treatment for AIS mainly focuses on the correction of the spinal deformity. It is not yet known how the gibbosity is related to the spinal deformity. The aim was to quantify the relationship between the gibbosity and the 3D deformity of the scoliotic spine. Material and methods Seventy-four subjects with AIS (62F, age: 15 ± 2 years, Cobb: 32° [20–50°]) age-matched to 44 controls (24F) underwent full-body biplanar X-rays with 3D reconstructions of the spine and the rib cage. Parameters were collected for the rib cage: maximum thickness, maximum width, gibbosity, rib cage volume, volumetric spinal penetration index. Sagittal spino-pelvic parameters (PI, PT, SS, TK, LL) were assessed as well as the frontal Cobb angle, and the axial rotation of the apical vertebra (AVR). A subset of the initial sample consisting of 30 subjects with AIS age-matched to 10 control subjects were considered for the repeatability assessment and had their rib cages reconstructed 3 times by 6 trained operators. The reliability was assessed on this subset using the Intraclass Correlation Coefficients (ICC). The 95% confidence interval (CI), including both intra and inter-observer variability, was calculated for each parameter (confidence in the estimate Results The reliability analysis of the 3D rib cage parameters showed an ICC > 0.98. The 95% CI of the gibbosity varied between 2.2° and 3.2°. The absolute value of gibbosity was significantly larger in scoliotics (6° ± 4° vs. 3° ± 2°, P Discussion 3D reconstructions of the rib cage, based on biplanar X-rays, were shown to be repeatable in both control and AIS subjects. This is the first study to investigate the relationship between the deformity of the rib cage and the one from the spine in subjects with AIS. AVR was shown to be the most determinant factor of gibbosity. Other unexplored factors, probably related to the mechanical properties of the ribs and soft tissues, could also be implicated in gibbosity generation.

Treatment of early-onset scoliosis with a hybrid of a concave magnetic driver (magnetic controlled growth rod) and a contralateral passive sliding rod construct with apical control: preliminary report on 17 cases

Background ContextMagnetic controlled growth rods (MCGRs) are increasingly popular for surgical treatment of severe early-onset scoliosis (EOS), because they allow noninvasive extensions with good growth maintenance. We combined an MCGR with a contralateral passive sliding rod construct with apical control on the convex side to improve efficiency in terms of costs and three-dimensional (3D) correction. PurposeTo investigate the feasibility, 3D correction, spinal growth, and complications of the apical control MCGR sliding rod hybrid. Study DesignTwo-center retrospective cohort study. Patient SampleA consecutive series of 17 children with EOS from two European spine centers were treated with the hybrid principle: 13 primary cases and 4 conversion cases from other growth instrumentation. Median age at surgery was 9 years (range: 6–18). Median follow-up time was 24 months (range: 12–31). OutcomesCobb angles (frontal Cobb, kyphosis, lordosis), rotation, spinal length gain, growth rate, and complications. MethodsRadiographs and patient files were reviewed. All the patients received fully financed treatment within the national public health-care systems. ResultsMean preoperative frontal Cobb angle was 59°, reduced postoperatively to 30° and was maintained throughout follow-up. Mean rotation of the apical vertebra improved from 27° to 18°, but was partially lost over time. Kyphosis decreased and lordosis was largely unaltered. Instrumented spine growth was maintained at a mean of 12 mm per year. One child had surgical revision because of progressive trunk shift, unrelated to the technique. The same child fell and sustained T1 and T2 fractures that were treated conservatively. Another child is planned for revision because of MCGR distraction failure. ConclusionThese early results show satisfactory frontal Cobb curve reduction and maintenance of spinal growth after using a new hybrid concept of a single magnetic growth rod and contralateral apical control sliding rods. A single magnetic growth rod in this combination may work equally well as traditional or dual magnetic growth rods. This new concept may represent a significant gain in both cost-effectiveness of growth rod treatment and 3D correction in EOS.

The Development of a Representative Porcine Early-Onset Scoliosis Model With a Standalone Posterior Spinal Tether

Study DesignIn vivo analysis in a porcine model. ObjectivesTo develop a porcine experimental scoliosis model representative of early-onset scoliosis (EOS) with the use of a radiopaque ultra-high molecular weight polyethylene (UHMWPE) posterior spinal tether. Summary of Background DataLarge animal experimental scoliosis models with substantial growth potential are needed to test new fusionless scoliosis correction techniques. Previously described scoliosis models involve rib procedures, which violate the thoracic cage and affect subsequent corrective procedures. Models omitting these rib procedures have experienced difficulties in producing persistent three-dimensional structural deformities representative of EOS. MethodsScoliosis was induced in 14 immature pigs using an asymmetric posterior radiopaque UHMWPE spinal tether fixated to an offset device at lumbar and thoracic levels. Radiographs were taken at 2-week intervals, and frontal and sagittal Cobb angles were measured. A tether release was performed at the 10-week follow-up, and the animals were observed for another 10 weeks. ResultsFour animals had complications (infections and/or screw breakout) and were excluded from the study. Eight animals developed progressive curves with a mean frontal Cobb angle of 62°. A thoracic lordosis (34°) and a thoracolumbar kyphosis (22°) formed. CT analysis, acquired prior to tether release, showed a mean vertebral rotation of 37° at the apex with a mean vertebral wedge angle of 10°. After tether release, the frontal Cobb angles decreased to 46° at the 20-week follow-up. Sagittal curvature was not substantially affected after tether release. ConclusionsWe describe a large animal scoliosis model, which exhibits a substantial deformity in three planes without the use of rib procedures additional to a posterior spinal tether. The created deformities showed persistence after tether release. With the management of infection and enhancement of instrumentation stability, the creation of a valid model for testing new devices in fusionless scoliosis surgery seems feasible. Level of EvidenceLevel V.

Spino-pelvic coronal and sagittal alignment in Down's syndrome patients

Orthopedic conditions are common in subjects with Down's syndrome. Few studies have investigated spinal deformities in the frontal and sagittal planes but none have analyzed the pelvic parameters in relation to the spine. The aim was to describe the scoliotic deformities and sagittal spino-pelvic alignment in subjects with Down's syndrome. Forty-one subjects (13 F, 28 M, age 17.4 A 6.2 years) with Down's syndrome, without history of cardiac surgery, had undergone full body biplanar X rays with 3D reconstructions of their spine and pelvis. Subjects were age and gender-matched to 41 asymptomatic subjects (13 F, 28 M, age 17.7 A 5.4 years). Spinal and pelvic parameters were calculated: thoracic kyphosis (TK- T1–T12 and T4–T12), lumbar lordosis (LL- L1–L5 and L1–S1), coronal Cobb angle, axial rotation of the apical vertebra, pelvic incidence (PI), pelvic tilt (PT) and sacral slope (SS). Spino-pelvic parameters were compared between both groups using Student's or Mann-Whitney's tests. Since scoliosis can influence sagittal spinal curvatures, ANCOVA test was used to compare kyphosis and lordosis between groups while eliminating the frontal Cobb angle as a confounding factor. Significance level was set at 0.05. Significant differences on spino-pelvic parameters were found between the Down's syndrome and control group: pelvic incidence (53° vs. 45°, p = 0.01), sacral slope (48° vs 37°, p = 0.01), pelvic tilt (5° vs 8°, p = 0.009), L1–L5 (54° vs 44°, p = 0.001), L1–S1 (69° vs 57°, p = 0.01), T4–T12 (29° vs 38°, p = 0.001), number of patients where the Cobb angle was > 10° (20 subjects vs 8 subjects, p = 0.005), Cobb angle (11.5° vs 8°, p = 0.001), apical vertebral rotation (7° vs 4°, p = 0.001). After adjusting for Cobb angle, T1–T12, T4–T12, L1–L5 and L1–S1 remained significantly different between groups ( p

Role of Intraoperative Radiographs in the Surgical Treatment of Adolescent Idiopathic Scoliosis.

One of the main goals of scoliosis surgery is to obtain a balanced fused spine. Although preoperative planning remains essential, intraoperative posteroanterior radiographs are the only available tool during the procedure to verify shoulder and coronal spinal balance and, if necessary, adjust the construct. The aim of this study was to quantify the direct influence of intraoperative radiographs on the surgical procedure itself during correction of adolescent idiopathic scoliosis. Retrospective analysis of prospectively collected data on a monocentric cohort of adolescent idiopathic scoliosis patients undergoing corrective surgery. A total 148 consecutive patients operated in the same department following the same validated preoperative planning method were included in this prospective radiologic study. The mean follow-up averaged 33 months. Frontal Cobb angles, T1 tilt, shoulder tilt, iliolumbar angle, and frontal balance were measured and compared on intraoperative, early postoperative, and latest follow-up radiographs. Any intraoperative modification of the correction performed after analysis of the intraoperative radiograph were recorded. The analysis of all radiologic parameters was possible in 90.5% of the cases. In 9.5% of the cases, shoulders could not be properly distinguished. Significant modifications on the upper thoracic curve to correct T1 tilt or shoulder balance were performed in 29% of the patients, and changes at the distal levels were recorded in 19%, underlining planification imperfections. On postoperative standing radiographs, the average coronal parameters were neutral, without loss of correction at follow-up. Intraoperative radiographs remain necessary to ensure compensation of the shortcomings of the modern preoperative planification method.

Adolescent idiopathic scoliosis correction achieved by posteromedial translation using polyester bands: A comparative study of subtransverse process versus sublaminar fixation

PurposeSublaminar polyester bands have been used in hybrid construct to achieve correction of adolescent idiopathic scoliosis since 2003. Despite the reported safety of the bands, some surgeons remain reluctant at the idea of approaching the canal because of the potential neurological complications reported with the Luque wiring. Sub transverse bands might be an alternative. The present study is the first to compare sublaminar polyester band fixation to fixation of polyester bands around the transverse processes in hybrid constructs used to treat AIS. MethodsTwo cohorts of consecutive patients treated for thoracic AIS were retrospectively reviewed, with a minimum 2-year follow-up. Posteromedial translation was used for main curve correction in all cases. Sublaminar polyester bands were used in group 1 (20 patients). In group 2 (20 patients), the same implant was used, but the bands were passed around the transverse process instead of the lamina. Radiographic analysis included frontal Cobb angle measurements for each curve, thoracic kyphosis and rotation of the apical vertebra (RVA). ResultsMean operative time was similar in groups 1 and 2 (235±35 and 240±30minutes, respectively). Mean frontal correction achieved for the main curve was similar in both groups, 62.5±17.4% in group 1 and 54.1±19.4% in group 2. Sagittal correction was similar, with a final mean thoracic kyphosis of 30.9°±9.7° and 27.8°± 6.8° in group 1 and 2, respectively. Correction of RVA was similar in both groups postoperatively, 65.8% (±29.1) and 54.4% (±42.7) in group 1 and 2 respectively. No transverse process or lamina fracture was observed during insertion of the bands or curve correction in any of the groups. ConclusionThis study confirms that anchorage of Universal clamps (UCs) around transverse processes is a safe and efficacious technique in both the frontal and sagittal planes, providing a useful alternative for the correction of moderate AIS. UCs attached to transverse processes can achieve correction of moderate AIS similar to that obtained with sublaminar UCs while further reducing risks of vertebral canal complications. Level of evidenceLevel IV.

Voie antérieure versus voie postérieure dans la correction tridimensionnelle de la scoliose idiopathique de l’adolescent : une méta-analyse

Systematic review was conducted to compare effectiveness and safety of anterior and posterior surgical approach in three-dimensional correction of adolescent idiopathic thoracic scoliosis. Data sources were Medline and Scopus databases. We included studies on the use of either anterior or posterior instrumentation, or their combination, in surgical correction of adolescent idiopathic thoracic scoliosis, with at least 10 enrolled patients, aged less than 20 years at the time of surgery, and a follow-up of at least 24 months. A study was eligible if it reported the number of patients, mean estimate and dispersion of three key outcome measures (frontal and sagittal Cobb angle, apical vertebra rotation according to Perdriolle) at three measurement points (preoperatively, postoperatively, at follow-up). The quality of studies was assessed using the scale by Pilkington. Although 24 articles met the inclusion criteria, no randomized controlled trials (RCTs) was identified. None of the articles was of high quality. Both instrumentations provided a similar degree of reduction of frontal Cobb angle. Long-term effects of surgical correction on the sagittal Cobb angle seemed to be more stable in patients treated by posterior approach, while the anterior approach was more effective in the reduction of apical vertebral rotation. The surgery parameters were more favorable for anterior approach, particularly for the number of fused vertebrae. Although the available evidence favors neither of the two approaches, our study revealed several important issues: the reports are heterogeneous and provide incomplete relevant information. High-quality studies, particularly RCTs, are called for. Level II.

Anterior versus posterior approach in 3D correction of adolescent idiopathic thoracic scoliosis: A meta-analysis

Systematic review was conducted to compare effectiveness and safety of anterior and posterior surgical approach in 3D correction of adolescent idiopathic thoracic scoliosis. Data sources were MEDLINE and SCOPUS databases. We included studies on the use of either anterior or posterior instrumentation, or their combination, in surgical correction of adolescent idiopathic thoracic scoliosis, with at least 10 enrolled patients, aged less than 20 years at the time of surgery, and a follow-up of at least 24 months. A study was eligible if it reported the number of patients, mean estimate and dispersion of three key outcome measures (frontal and sagittal Cobb angle, apical vertebra rotation according to Perdriolle) at three measurement points (preoperatively, postoperatively, at follow-up). The quality of studies was assessed using the scale by Pilkington. Although 24 articles met the inclusion criteria, no randomized controlled trials (RCT) was identified. None of the articles was of high quality. Both instrumentations provided a similar degree of reduction of frontal Cobb angle. Long-term effects of surgical correction on the sagittal Cobb angle seemed to be more stable in patients treated by posterior approach, while the anterior approach was more effective in the reduction of apical vertebral rotation. The surgery parameters were more favorable for anterior approach, particularly for the number of fused vertebrae. Although the available evidence favors neither of the two approaches, our study revealed several important issues: the reports are heterogeneous and provide incomplete relevant information. High quality studies, particularly RCT, are called for. Level II.

Assessment of the prevalence of kyphosis disorders in students

The aim of this study was to assess the prevalence of kyphosis disorders in students. Total of 502 students in three levels including primary (99 girls, 99 boys), guidance (47...

Intrasacral Rod Fixation for Pediatric Long Spinal Fusion: Results of a Prospective Study With a Minimum 5-year Follow-up

Lumbosacral fusion is often needed in cases of pediatric neuromuscular spinal deformities. Despite the numerous fixation techniques described, the procedure remains challenging. Jackson has described a method of intrasacral fixation providing immediate 3-dimensional stability and promising clinical results. The purpose of this study was to report our experience with long spinal fusion using Jackson intrasacral fixation in pediatric patients. All patients with at least 5 years of follow-up were reviewed. No brace was used postoperatively. Clinical data and radiographs were collected and analyzed preoperatively, postoperatively, and at latest follow-up. Intraoperative and postoperative complications were reported. Paired t test was used for statistical analysis. Fifty-six patients were included. The average age at surgery was 15.3 years. Mean follow-up period was 10.3 years and no patient was lost to follow-up. All radiographic parameters (frontal balance, frontal Cobb angle of the primary curve, iliolumbar angle, pelvic obliquity, sagittal balance, lumbosacral lordosis, and sacral slope) were significantly improved postoperatively (P<0.001), without significant loss of correction at latest follow-up. Four early infections, 1 pressure sore, and 4 cases of radicular pain, which resolved without intervention, were reported postoperatively. At latest follow-up, no patient complained of lumbar pain, and neither ambulatory status nor activity level ability worsened in any case. Sixteen of the 20 patients who needed a sitting orthosis preoperatively achieved a functional sitting posture without bracing. Jackson fixation is a safe and reliable technique providing immediate stability. In our series, no mechanical complication occurred and no loss of correction was observed, despite immediate unprotected mobilization. The method provides reliable good sacral fixation for pediatric neuromuscular spinal deformities, especially when the correction of severe pelvic obliquity is necessary. This consecutive series provides level IV evidence.

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.

A Clinical Impact Classification of Scoliosis in the Adult

Multicenter, prospective, consecutive clinical series. To establish and validate classification of scoliosis in the adult. Studies of adult scoliosis reveal the impact of radiographic parameters on self-assessed function: lumbar lordosis and frontal plane obliquity of lumbar vertebrae, not Cobb angle, correlate with pain scores. Deformity apex and intervertebral subluxations correlate with disability. A total of 947 adults with spinal deformity had radiographic analysis: frontal Cobb angle, deformity apex, lumbar lordosis, and intervertebral subluxation. Health assessment included Oswestry Disability Index and Scoliosis Research Society instrument. Deformity apex, lordosis (T12-S1), and intervertebral subluxation were used to classify patients. Outcomes measures and surgical rates were evaluated. Mean maximal coronal Cobb was 46 degrees and lumbar lordosis 46 degrees . Mean maximal intervertebral subluxation (frontal plane) was 4.2 mm (sagittal plane, 1.2 mm). In thoracolumbar/lumbar deformities, the loss of lordosis/higher subluxation was associated with lower Scoliosis Research Society pain/function and higher Oswestry Disability Index scores. Across the study group, lower apex combined with lower lordosis led to higher disability. Higher surgical rates with decreasing lumbar lordosis and higher intervertebral subluxation were detected. A clinical impact classification has been established based on radiographic markers of disability. The classification has shown correlation with self-reported disability as well as rates of operative treatment.

Correction of flexible thoracic scoliosis below 65 degrees—A radiological comparison of anterior versus posterior segmental instrumentation applied to similar curves

Direct comparison of the correction of scoliosis achieved by different surgical methods is usually limited by the heterogeneity of the patients analyzed (their age, curve pattern, curve magnitude, etc.). The hypothesis is that an analysis of comparable scoliotic curves treated by different implant systems could detect subtle differences in outcome. The objective of this study was therefore: (1) to measure the 3D radiological parameters of scoliotic deformity and to quantify their postoperative changes, and (2) to compare the radiographic results achieved with one anterior and one posterior instrumentation methods applied to similar curves but representing different mechanisms of correction. The clinical notes and radiographs of 46 patients operated on for adolescent idiopathic scoliosis were reviewed. The inclusion criteria consisted of: a single thoracic curve, right convex, a frontal Cobb angle minimum of 45 degrees and a maximum of 65 degrees , flexibility on a lateral bending test of more than 30%, and a Risser test value of between 1 and 4. The operative procedures were: Cotrel-Dubousset instrumentation (CDI) for 25 patients (the CD group) and correction by anterior instrumentation (Pouliquen plate) for 21 patients (the ANT group). Preoperative and postoperative long cassette standing antero-posterior and lateral radiographs were examined. The frontal and sagittal thoracic Cobb angle, apical vertebra transposition (AVT), apical vertebra rotation (AVR), lowest instrumented vertebra (LIV) tilt, C7 vertebra shift and rib cage shift (RCS) were all compared. A computed reconstruction was produced with Rachis-91 software. Vertebral axial rotation angle was evaluated throughout the spine. Postoperative assessment revealed a mean correction of the frontal Cobb angle of 37.0 degrees for the CD group and 41.0 degrees for the ANT group. The AVT operative correction was 45.8 and 42.7 mm, respectively, and AVR correction was 1.8 and 12.6 degrees , respectively. The postoperative change of the sagittal Th4-Th12 Cobb angle was not significant for any method but it was significant (P=0.05) for the CD group if the curves were divided preoperatively into hypokyphotic and normokyphotic subgroups and then analyzed separately. Computed assessment demonstrated a correction of segmental axial rotation of more than 50% in the main thoracic curve in the ANT group, significantly more than that in the CD group (P<0.001). Anterior instrumentation provided better correction of the vertebral axial rotation and of the rib hump. CD instrumentation was more powerful in translation and more specifically addressed the sagittal plane: the postoperative thoracic kyphosis angle increased in the hypokyphotic curves and slightly decreased in the normokyphotic curves.

Assessment of Curve Flexibility in Adolescent Idiopathic Scoliosis

A prospective comparative evaluation of the commonly accepted or described radiologic techniques to determine curve flexibility in adolescent idiopathic scoliosis (AIS), comparison of the results to those obtained by supine traction radiographs taken with the patient under general anesthesia (UGA) just before surgery and correlation of all findings to surgical correction. To determine if supine traction radiographs taken with the patient UGA help provide better assessment of curve flexibility and better predicting surgical correction. Supine lateral bending radiographs are the standard methods of evaluating curve flexibility before surgery in idiopathic scoliosis. Supine traction radiographs have also been used at the authors' institution in addition to the supine lateral bending radiographs before surgery, believing that it is usually more helpful to analyze the response of the main and compensatory curves to corrective forces. A total of 34 consecutive patients with AIS who had surgical treatment were studied. Preoperative radiologic evaluation consisted of standing anteroposterior and lateral, supine lateral bending and traction, fulcrum bending radiographs, and also supine traction radiographs taken with the patient UGA just before surgery. All structural curves were measured, and the flexibility ratio was determined on each radiograph. The amount of correction obtained by all radiographic methods was compared with the amount of surgical correction by evaluating the differences from surgery as absolute values. Mean absolute differences from surgery were used to determine the confidence intervals. Statistical differences were calculated with the comparison of the exact 95% confidence intervals for the mean. Curves were accepted to be moderate if between 40 degrees and 65 degrees (29 patients) and severe if >65 degrees (5 patients). In these 29 patients, average frontal Cobb angle of the thoracic and lumbar curves were 49.7 degrees (range 40 degrees-60 degrees) and 39.4 degrees (range 22 degrees-58 degrees), respectively. For the moderate thoracic curves, fulcrum radiographs provided the best amount of flexibility, with no significant difference from traction with the patient UGA but with significant difference from bending radiographs. For the moderate lumbar curves, flexibility obtained by fulcrum and bending radiographs were significantly better than traction radiographs with the patient UGA. For the lumbar and thoracic curves more than 65 degrees, traction radiographs with the patient UGA provided clearly better flexibility compared to bending and fulcrum radiographs, however, the number of patients is not enough to determine whether the differences are statistically significant. Better flexibility in traction radiographs with the patient UGA helped us eliminate the need for anterior release in all 5 patients who had severe and rigid curves more than 65 degrees, which did not bend to less than 40 degrees and were planned to have anterior release. Fulcrum higher than bending higher than traction with the patient UGA is the order of radiographs for better predicting flexibility and correction in curves between 40 degrees and 65 degrees. Flexibility obtained at traction radiographs with the patient UGA is clearly better in numerical values, and closer to the amount of surgical correction than the amount of flexibility at fulcrum and side-bending radiographs for curves larger than 65 degrees, although not statistically significant as a result of the small number of patients in this group. However, pedicle screw instrumentation provides even more correction than the traction radiographs with the patient UGA. Thus, traction radiographs with the patient UGA may show much better flexibility, especially in more than 65 degrees and rigid curves.

Three-Dimensional Morphological Modeling of Scoliotic Spine.

Scoliosis is a spinal deformity that is defined as a pathological frontal curvature with decrease of the physiological sagittal curvature, and must be evaluated three-dimensionally. We present a morphologic curve to express the three-dimensional configuration of a scoliotic spine from two plane radiograms, and evaluate spinal curvature three-dimensionally. The morphologic curve can be formulated from two plane curves approximating the frontal and sagittal arrangements of the centers of vertebral bodies. Furthermore, the Cobb angle, which is widely used in orthopaedics, can be calculated three-dimensionally as the maximum angle between two tangent vectors of the morphologic curve. In 45 spines with idiopathic scoliosis, the configurations of spines were extremely well approximated by the morphologic curves. Three-dimensional Cobb angle was significantly larger than frontal Cobb angle. Since the three-dimensional Cobb angle includes the sagittal and frontal curvatures, it can be used for three-dimensional evaluation of the scoliotic spine.