Rib Vertebral Angle Difference Research Articles

Treatment of infantile idiopathic scoliosis using a novel thoracolumbosacral orthosis: a case report

BackgroundThe recommended treatment for mild to moderate infantile idiopathic scoliosis curves involves serial casting. There are concerns, however, regarding the safety of repeated casting in very young children owing to the requirement for anesthetization during the casting process. Very little research has been conducted on the influence of bracing as an initial treatment for scoliosis in this age group. This report details the successful treatment of a large thoracic curve using a thoracolumbosacral orthosis in an infant diagnosed with infantile idiopathic scoliosis.Case presentationThe Dutch-Australian patient presented at 11 weeks of age with a 44° thoracic scoliosis and a rib vertebral angle difference of 14°. The history and physical examination failed to reveal a cause of the curvature, and a diagnosis of infantile idiopathic scoliosis was made. The patient was prescribed a thoracolumbosacral orthosis (ScoliBrace) to be worn on a part-time basis for a period of 8 months. At the end of the bracing program, the patient’s curve had been reduced to 7° and a rib–vertebral angle difference of 0°. A final follow-up of the patient at 2 years after the cessation of treatment revealed no evidence of scoliosis. The parents were compliant with the bracing protocol and reported that the treatment was tolerated by the infant.ConclusionThe use of an orthosis as a standalone treatment in this patient resulted in significant reduction in a large thoracic scoliosis. Based on the results witnessed in this patient, further investigation into bracing as an alternative to casting is warranted.

Comparison of two types of casting in early-onset scoliosis.

Early-onset scoliosis (EOS) can be a progressive and debilitating condition if left untreated. Different casting techniques have fallen in and out of favor over the years for conservative management. Two types of casting, elongation-derotation-flexion (EDF) and body casting (BC) are employed at our institution. Here we compare the radiographic outcomes between these two types of casting in a cohort of patients diagnosed with EOS. Sixteen children with EOS were treated by EDF serial casting while seventeen children with the same diagnosis were treated by BC. Radiographic measurements included Cobb angle, rib-vertebral-angle difference (RVAD) and vertebral rotation (VR) by Nash-Moe method in casting (IC) or out of casting (OOC), thoracic height (TH) and width (TW). All of the patients had x-ray measurements at pre-casting OOC, 1st IC and final post-casting OOC. Casts were changed every 2-4 months. Independent two sample t-test, Wilcoxon rank-sum test, and Chi-square test were performed. There were no significant differences at the initial treatment for age, classification of EOS, OOC, RVAD, VR, kyphosis, TH, and TW between EDF and BC casting. There were no significant differences of changes for OOC, RVAD, VR, kyphosis, TH and TW from pre-casting to the final post-casting status between two casting techniques (P>0.05). However, children with EDF tended to receive 3 to 4 more castings than those with BC (7.5 vs.4 casts) (P=0.007) and achieved better outcomes in success (25% vs.20%) and improvement (50% vs.10%) (P=0.03). EDF has better outcomes with EOS improvement when there is treatment of longer duration.

Follow-up of an Elongation Bending Derotation Brace in the treatment of infantile scoliosis.

Since 2013, an elongation bending derotation brace (EBDB) has been developed and applied to EOS in our institution. The goals of the study were: 1) to compare radiographic changes before the use of EBDB (Pre-B), in brace (IB), and after the use of EBDB (Post-B) in a minimal two year follow-up; 2) to determine the compliance with the EBDB. Thirteen children diagnosed with an infantile scoliosis (IS) were retrospectively recruited. Under general anesthesia in the OR, child was placed on a Spica casting table, and the spine was manipulated by stockinet straps. Then 3D child's torso was scanned, the EBDB was designed and manufactured for exact fitting to the torso in the corrected position using CAD/CAM technology.1 Mean age at start of EBDB was 2 years and 6 months. Average follow-up was 36 months. Compliance showed a mean 19 hours per day (14 to 23 hours). Pre-treatment Cobb angle was 40°, in brace 22°, and out of brace 28°(p<0.05). Axial vertebral rotation (AVR) by Nash-Moe method improved from 30% before treatment to 21% in brace and 19% at the end of visit (p<0.05). Kyphosis was significantly increased from 16°(Pre-B) to 32°(Post-B) (P<0.05). However, there was reduction of Rib-vertebral angle difference (RVAD) from 23°(Pre-B) to 11°(Post-B) (P>0.05). A cascade of EBDB effectively corrects and stabilizes the 3D spinal deformities in infantile. Thus the EBDB is considered as a successful modality in the treatment of IS children.

Three-dimensional reconstruction image by biplanar stereoradiography reflects pulmonary functional states in adolescent idiopathic scoliosis

This study investigated whether the rib cage parameters estimated based on reconstructed three-dimensional (3D) images with biplanar stereoradiography reflect pulmonary functional states in adolescent idiopathic scoliosis (AIS) patients. A total of 67 Lenke type 1 or 2 AIS patients (59 females and 8 males, mean age 14.4 years) were enrolled. All patients underwent preoperative pulmonary functional tests (PFT) and biplanar stereoradiography. Vital capacity (VC) and forced vital capacity (FVC) pulmonary functional data were collected. Rib-cage parameters (maximum thickness, maximum width, thoracic index (TI), rib hump (RH), rib-cage volume (RCV), spinal penetration index (SPI), endothoracic hump ratio (EHR), vertebra–sternum angle (VSA), rib vertebral angle difference (RVAD), and vertebral lateral decentering (VLD)) were quantified from 3D images. Patients were divided into two groups: restrictive lung disorder (RLD) (%FVC < 80%) and non-RLD (%FVC ≥ 80%). The maximum width and RCV were significantly correlated with VC (p < 0.0001), and FVC (p < 0.0001). RH, EHR, and VSA were negatively correlated with %FVC (p < 0.01). TI, SPI, and RVAD were not correlated with any pulmonary parameters. The maximum widths of RLD patients were significantly shorter than those of the non-RLD patients (218.3 mm vs. 229.7 mm, p < 0.01). The RCV of RLD patients was significantly smaller than that of the non-RLD patients (3.94 L vs. 4.49 L, p < 0.0001). The maximum width and RCV measured by 3D images with biplanar stereoradiography reflected pulmonary functional variables in patients with AIS.

Role of Body Cast Application for Scoliosis Associated With Prader-Willi Syndrome.

Prader-Willi syndrome (PWS) is a rare genetic syndrome, with a prevalence of infantile scoliosis of ~23%. These curves are likely related to severe hypotonia. Approximately 15% of children with PWS will need surgical intervention for their scoliosis. The purpose of this study was to evaluate the effectiveness of curing or controlling moderate and severe infantile scoliosis curves in children with PWS. This single institution, retrospective study of patients with PWS and infantile scoliosis reviewed 34 consecutive children with >24 months follow-up from initiation of serial spinal casting. Cobb angle comparison measurements of radiographs taken precasting, during treatment, and at follow-up were performed. Rib-vertebral angle difference, Nash-Moe rotation, and space available for lung measurements were followed. Outcomes were stratified as "Cured," "Braced," and "Surgery." Average age for first cast for the entire study was 32 months (range, 14 to 64), undergoing 8 casts (range, 3 to 18) over 25 months (range, 9 to 57) for an initial curve of 54 degrees (range, 27 to 106 degrees), which improved to 27 degrees (range, 11 to 78 degrees). In total, 12 patients (35%) were in the Cured group, following 6 casts over 17 months, with an initial curve of 44±14 degrees improving to 17±5 degrees at the end of treatment, and 20±18 degrees at 68-month follow-up. In total, 18 patients were in the Braced group, with curves initially improving from 55±14 degrees to 35±14 degrees, but at 47±20 degrees at 51-month follow-up. Four patients needed surgery, with initial curves 85 degrees (range, 54 to 106 degrees), but surgery could be postponed 56 months (range, 40 to 73) by casting. Rib-vertebral angle difference was not prognostic. Serial spinal casting is effective in for treating infantile scoliosis in children with PWS. One third of patients had their curve resolved, at least temporarily, where they were braced and cast free. The others were able to delay surgery for a number of years. Initial curves <50 degrees in children <3 years of age seem to have the best prognosis. Level IV.

Three-Dimensional Analysis of Preoperative and Postoperative Rib Cage Parameters by Simultaneous Biplanar Radiographic Scanning Technique in Adolescent Idiopathic Scoliosis: Minimum 2-Year Follow-Up.

Prospective study. This study aimed to investigate the changes in rib cage deformity in adolescent idiopathic scoliosis (AIS) by comparing the preoperative and postoperative three-dimensional (3D) reconstruction images using simultaneous biplanar radiographic scanning technique (EOS) (EOS Imaging, Paris, France). EOS data are limited for the analyses of preoperative and postoperative rib cage deformity. A total of 67 Lenke type 1 or 2 AIS patients who underwent surgery (59 females and 8 males) were enrolled in this study. The mean patient age was 14.4 years (range: 11-17 yr). In all patients, posterior corrective fusion was performed with a rod rotation maneuver based on segmental pedicle fixation. Spinal parameters (scoliosis and kyphosis) and rib cage parameters (max thickness, thoracic index (TI), rib hump (RH), surface spinal penetration index (sSPI), end thoracic hump ratio, vertebra-sternum angle, rib vertebral angle difference at the apex, and vertebral lateral decentering), were measured. 3D images were assessed preoperatively and postoperatively at 2-year follow-up. Both main thoracic (MT) and proximal thoracic scoliosis were significantly corrected (51° to 15°, 30° to 17°, P < 0.0001). The rotation of MT apical vertebrae was also significantly corrected (12° to 5°, P < 0.0001). Thoracic kyphosis (T4-T12) significantly increased (13° to 18°, P < 0.0001). Besides, max thickness, TI, and RH demonstrated significant differences between preoperative and postoperative images (P < 0.01). T8-10 sSPI and end thoracic hump ratio decreased significantly postoperatively (P < 0.05). Although surgery significantly decreased vertebra-sternum angle (P < 0.0001), no significant difference was observed between the preoperative and postoperative rib vertebral angle difference (P = 0.32). Following the surgery, vertebral lateral decentering and rib cage volume were significantly increased (P < 0.0001). 3D reconstruction of the rib cage using biplanar standing stereoradiography is useful to evaluate preoperative and postoperative rib cage deformity in patients with AIS.Level of Evidence: 2.

Accuracy of rib cage parameters from 3-Dimensional reconstruction images obtained using simultaneous biplanar radiographic scanning technique in adolescent idiopathic scoliosis: Comparison with conventional computed tomography

Simultaneous biplanar radiographic scanning technique (EOS) (EOS Imaging, Paris, France) variability has previously been evaluated for spinal parameters, however limited EOS data exist regarding accuracy of 3-dimensional (3D) rib cage reconstruction. The purpose of this study was to compare the evaluation of ribcage parameter between EOS 3D images and 3D computed tomography (CT) images from adolescent idiopathic scoliosis (AIS) patients, and validate the accuracy of EOS 3D ribcage reconstruction images. In total, 31 AIS patients (27 females, 4 males; mean age 14.4 years) with Lenke types 1 or 2 who underwent corrective surgery were enrolled. EOS 3D images were assessed preoperatively for all patients. Rib cage parameters were measured, including surface spinal penetration index (sSPI), endothoracic hump ratio (EHR), vertebra-sternum angle (VSA), rib-vertebral angle difference (RVAD) at apex and vertebral lateral decentering (VLD). Measurements were subsequently compared with CT images. No significant differences were observed in sSPI or EHR measurements between EOS and CT images. Measured VSA values from EOS and CT were −28.1 degrees and −26.1 degrees, respectively. Measured RVAD values from EOS and CT were 13.0 degrees and 12.0 degrees, respectively. No significant differences were observed for measured VSA or RVAD values between EOS and CT images. Measured VLD values from EOS and CT were 68.5% and 67.5%, respectively, representing similar values. The accuracy of rib cage parameters measured with EOS software is similar to the measurements obtained with CT. The results of this study provide surgeons with important evidence pertaining to this novel imaging technology.

Radiographic and Respiratory Effects of Growing Rods in Children With Spinal Muscular Atrophy.

Respiratory weakness and spinal deformity are common in patients with spinal muscular atrophy (SMA). Posterior (distraction type) growing rods have recently gained favor as a treatment option in this population, due to their ability to prevent spinal deformity progression and their potential to allow lung volumes to increase over time. The objective of this study was to determine the impact of posterior growing rods on the spinal alignment and respiratory function in children with SMA with intermediate term follow-up. A single center, retrospective review was performed on SMA patients treated with growing rods, inserted between 2004 and 2010, with a minimum of 2-year follow-up. SMA type, changes in the route of bi-level positive airway pressure respiratory support and the amount of time receiving respiratory support are reported. Pulmonary function tests (PFTs) and radiographs were reviewed and data evaluated preinsertion, postinsertion, and at latest follow-up. Sixteen children with SMA (5 type I, 11 type II) met inclusion criteria. The average age of insertion was 5.8 (±1.5) years, the median number of lengthenings was 4 (range, 3 to 5), and the median time between insertion and last clinical review was 4.7 (range, 2.7 to 9.5) years. Radiographic review demonstrated significant (P<0.05) improvements in the following: Spinal curve magnitude, pelvic obliquity, space available for the lung, rib vertebral angle difference, and thoracic kyphosis following growing rod implantation. Thoracic and lumbar height and chest width and depth increased significantly (P<0.05) over the lengthening process. None of the patients initially required more than noninvasive positive pressure ventilation support. Fifteen of the 16 experienced no changes in their noninvasive positive pressure ventilation support needs throughout the study duration, requiring support only at night and naps. Serial PFTs were available for 6 children with SMA type II. PFTs demonstrated significant improvements in absolute forced vital capacity (FVC), minimal changes in the maximal inspiratory and expiratory pressures, and a gradual worsening of percent predicted FVC. Clinical respiratory support requirements appear to stabilize following the insertion and lengthening of posterior based growing rods in the SMA population. Similar to previous studies, increased spinal height and thoracic cavity size were noted throughout the process. Despite an increasing absolute FVC, the percent predicted FVC diminished over time. Level IV-therapeutic.

Serial Mehta Cast Utilization in Infantile Idiopathic Scoliosis: Evaluation of Radiographic Predictors

Mehta cast utilization has gained a considerable momentum as a nonoperative treatment modality for the initial management of infantile idiopathic scoliosis (IIS). Despite its acceptance, there is paucity of data that characterize the radiographic parameters associated with Mehta casting and the factors correlated with a sustained curve correction. A retrospective review of IIS patients who underwent Mehta casting was performed with a mean 2-year follow-up. X-rays were evaluated at each visit for the Cobb angle, focal deformity, rib-vertebral angle difference, and height of concavity and convexity of the apical 3 vertebrae. Concave-to-convex height ratios were calculated and tracked for each patient. Radiographic parameters were compared from precasting to after final casting, and from final casting to most recent follow-up. A total of 45 patients were identified, of whom 18 (40%) were male and 27 (60%) were female, with a mean age of 18.8±9.5 months at first casting and a mean follow-up of 37.7±19.7 months. Following final casting, the mean Cobb angle (25.6 vs. 52.7 degrees), focal deformity (17.4 vs. 30.5 degrees), rib-vertebral angle difference (18 vs. 32.3 degrees), and the concave-to-convex height ratios improved relative to precast parameters, respectively (P<0.001). At final follow-up, mean Cobb angle (16.2 vs. 25.6 degrees) and concave-to-convex height ratios progressively improved when compared with final cast measurements, respectively (P<0.001). Five (11%) patients did not demonstrate sustained curve correction at final follow-up, whereas 4 (9%) required growing-rod placement. Lastly, the regression analysis demonstrated improvements in the focal deformity (17.4 vs. 30.5) and the concave-to-convex height ratios of the +1 and -1 apical vertebrae from the precast to last cast periods (P<0.001). These findings were correlated with sustained Cobb angle correction from cast removal to the most recent follow-up. Radiographic parameters associated with control of progressive deformity for IIS include improvements in focal deformity and concave-to-convex height ratios for +1 and -1 apical vertebrae after final casting. Mehta casting is an effective treatment for symptomatic IIS and continues to provide IIS patients with significant curve correction. Level IV.

Serial Casting for Infantile Idiopathic Scoliosis: Radiographic Outcomes and Factors Associated With Response to Treatment.

Serial casting for early-onset scoliosis has been shown to improve curve deformity. Our goal was to define clinical and radiographic features that determine response to treatment. We retrospectively reviewed patients with idiopathic infantile scoliosis with a minimum of 2-year follow-up. Inclusion criteria were: progressive idiopathic infantile scoliosis and initial casting before 6 years of age. Two groups were analyzed and compared: group 1 (≥10-degree improvement in Cobb angle from baseline) and group 2 (no improvement). Twenty-one patients with an average Cobb angle of 48 degrees (range, 24 to 72 degrees) underwent initial casting at an average age of 2.1 years (range, 0.7 to 5.4 y). Average follow-up was 3.5 years (range, 2 to 6.9 y). Sex, age at initial casting, magnitude of spinal deformity, and curve flexibility (defined as change in Cobb angle from pretreatment to first in-cast radiograph) were not significantly different between groups (P>0.05). Group 1 had a significantly higher body mass index (BMI) than group 2 at the onset of treatment (17.6 vs. 14.8, P<0.05). Univariate analysis of demographic, radiographic, and treatment factors revealed that only BMI was predictive of Cobb improvement (P=0.04; odds ratio=2.38). Group 1 (n=15) had a significantly lower Cobb angle (21 vs. 56 degrees) and rib vertebral angle difference (13 vs. 25 degrees) compared with group 2 at latest follow-up (P<0.05). A significantly larger proportion of children who were casted at less than 1.8 years of age had a Cobb angle <20 degrees at latest follow-up (P=0.03). Group 2 maintained stable clinical and radiograph parameters from pretreatment to most recent follow-up. To maintain a homogeneous cohort, we excluded patients with syndromes and developmental delays. We believe that analyzing a homogeneous group provides more meaningful results than if we studied a heterogeneous sample. BMI was significantly associated with outcome such that for each unit increase in BMI, there is a 2.38× increase in the chance of improvement. Curve flexibility was similar between groups, which suggest that the amount of correction obtained at initial casting does not confirm treatment success. Key aspects of treatment that may determine success include age of less than 1.8 years at initiation of casting and derotation of the spine to correct rib vertebral angle difference of <20 degrees. Level IV-Therapeutic.

Rib-vertebral angle measurements predict brace treatment outcome in Risser grade 0 and premenarchal girls with adolescent idiopathic scoliosis.

To investigate the predictive role of rib-vertebral angle (RVA) measurements in early adolescent idiopathic scoliosis (AIS) girls with right thoracic curve during brace treatment. Early AIS (premenarchal and Risser 0) girls who had undergone brace treatment and had been followed regularly were recruited to this study. According to the bracing outcome, they were divided into Group A (non-progressed) and Group B (curve worsened over six degrees or indicated for surgery). Totally 48 girls were included. There were 30 and 18 patients in Groups A and B, respectively. Ratio of curve progression was significantly higher in patients with initial RVA difference (RVAD) ≥20° versus <20°, or convex RVA (CRVA) ≤68° versus >68°. From brace initiation to the latest follow-up, CRVA was found to be significantly higher in Group A versus Group B (P<0.05), while RVAD was higher in Group B versus Group A (P<0.05). Serial measurements revealed an increasing trend for RVAD (from 19±10° to 29±8°) yet a decreasing trend for CRVA (from 68±6° to 60±7°) in Group B, but both RVAD and CRVA were found to remain stable in Group A during the follow-up period. Association analyses showed that both RVAD ≥20° and CRVA ≤68° at brace initiation and at each follow-up were significantly associated with curve progression. The initial RVAD ≥20° and CRVA ≤68° serve as valid factors in predicting the risk of curve progression during bracing in early AIS. Constant watch on RVAD and CRVA can help to more accurately predict the effectiveness of bracing in these patients.

Serial Derotational Casting in Idiopathic and Non-Idiopathic Progressive Early-Onset Scoliosis

IntroductionSerial derotational casting has been used as a definitive treatment or as delaying strategy in progressive idiopathic (IS) and non-idiopathic (NIS) early-onset scoliosis (EOS). MethodsRetrospective chart and radiographic review of patients who underwent serial casting for progressive EOS between 2005 and 2012 at a single institution. ResultsA total of 74 consecutive patients entered serial cast treatment. Twenty-eight were currently being casted, 30 completed cast treatment and were converted to thoracolumbosacral orthosis (TLSO), 9 were treated surgically, 6 were lost to follow-up, and 1 had no further treatment. The researchers diagnosed IS in 41 patients; 33 had NIS. At presentation the IS group had an average Cobb angle (CA) of 49° and a rib vertebral angle difference (RVAD) of 37°. The NIS group had a CA of 51° (p = .69) and RVAD of 37° (p = .94). In patients currently being casted, 19 IS patients had a decreased CA, from 47° to 27°. The 9 NIS patients had a decreased CA, from 62° to 57° (p = .0002). Cobb angle improvement was significantly better in IS (p = .0005). In the TLSO group the 17 IS patients had a decreased average CA, from 46° to 18°, after serial casting and the 13 NIS patients decreased CA from 42° to 32°. Patients with IS had better improvement in CA than the NIS group (p < .001). At last follow-up, this was reduced to 11° in the IS group and maintained at 32° in the NIS. In the IS group, 5 of 41 patients were converted to growth constructs, and 4 of 26 in the NIS group. Casting initiated before age 2 years yielded better curve correction for IS (p < .01) compared with NIS. ConclusionsProgressive idiopathic scoliosis patients had better curve correction with casting than NIS patients. Casting in IS patients before age 24 months yielded better curve correction. Patients who required surgery had a higher age and Cobb angle at presentation than those who transitioned to a TLSO. The surgical group was observed for a similar duration of time and there was no significant statistical difference. Although RVAD is a predictor of progression in infantile IS, it did not show a predictive value in the response to casting of either the IS or NIS groups.

Reliability of Radiographic Measures for Infantile Idiopathic Scoliosis

Radiographic measures such as the rib vertebral angle difference (RVAD), Cobb angle, and space available for the lung (SAL) help to guide treatment and measure treatment effects in patients with infantile idiopathic scoliosis. This study aimed to evaluate the intraobserver and interobserver reliability of these radiographic measures. Forty-five spine radiographs of skeletally immature patients (age, two months to four years) with infantile idiopathic scoliosis were measured with use of Surgimap software. Three pediatric orthopaedic surgeons and a pediatric orthopaedic fellow identified the major curve apex, rib-vertebra phase, Cobb angle, and end vertebrae and calculated the RVAD and SAL values at two separate time points. Interobserver and intraobserver reliability of the RVAD, Cobb angle, and SAL values were assessed with use of intraclass correlation coefficients (ICCs). Fleiss kappa coefficients were calculated for categorical variables. The RVAD (ICC = 0.86 to 0.92) and Cobb angle (ICC = 0.99) measurements had high reliability. The SAL value had substantial interobserver reliability (ICC = 0.66) and moderate intraobserver reliability (ICC = 0.73). Despite the high agreement for the Cobb angle, the choice of the major curve vertebrae (kappa = 0.19 to 0.39) and apical vertebra varied (kappa = 0.57 to 0.62). Observers were more likely to choose the same apical vertebra in large curves (r = 0.483, p = 0.001). The agreement for the apical rib-vertebra phase was substantial (kappa = 0.67). Paired RVAD measurements fell within ≤ 10° of each other in 82% of cases, but the remaining 18% of the RVAD measurements showed >10° of variation. Measurements used to guide treatment of infantile idiopathic scoliosis curves were reliable despite standard radiographic measurement error and the difficulty in obtaining quality images in young patients. Clinicians are dependent on seemingly objective radiographic data. The reliability of the Cobb angle and RVAD measurements in infantile scoliosis was high but not devoid of variability that could skew the ability to accurately and reliably suggest the best course of treatment. The SAL value was a less reliable measure. Treatment recommendations for infantile idiopathic scoliosis should rely on the synthesis of objective and clinically subjective data, as variations in radiographic measurements can lead to inconsistencies in management and to inconsistent treatment outcomes.

Rib-Vertebral Angle Difference and Convex Rib-Vertebral Angle as Risk Factors in Predicting Curve Progression during Bracing in Young Children with Idiopathic Scoliosis

Rib-Vertebral Angle Difference and Convex Rib-Vertebral Angle as Risk Factors in Predicting Curve Progression during Bracing in Young Children with Idiopathic Scoliosis

The Effect of Differing Spinal Fusion Instrumentation on the Occurrence of Postoperative Crankshaft Phenomenon in Adolescent Idiopathic Scoliosis

Retrospective. To compare the occurrence of the crankshaft phenomenon in patients with adolescent idiopathic scoliosis (AIS) who underwent hybrid, consecutive pedicle screw or interval pedicle screw instrumentation for posterior spinal fusion. Scoliosis may progress after posterior spinal fusion in skeletally immature patients with AIS. The crankshaft phenomenon occurs when the anterior column continues to grow in the face of posterior fusion causing characteristic twisting of the fused segment. The optimal surgical method for preventing the occurrence of this complication has not been determined. Sixty seven patients with AIS who underwent posterior fusion over a 6-year period were divided into groups according to fixation method: hybrid instrumentation, interval pedicle screw placement, or consecutive pedicle screw placement. Preoperative, postoperative, and follow-up radiographic measures, including Cobb angle, apical vertebral rotation (AVR), apical vertebral transposition (AVT), rib vertebral angle difference (RVAD) and trunk shift (TS) were assessed. The occurrence of the crankshaft phenomenon was determined. The mean follow-up duration was 36 months. There were no between-the-group differences in demographics or preoperative or immediate postoperative measures. At the last follow-up, significant differences among the groups were apparent for Cobb angle, AVR, AVT, RVAD, and TS (all P<0.05). Cobb angle, AVR, AVT, RVAD, and TS significantly increased between the postsurgery and the last follow-up in the hybrid instrumentation group (all P<0.0167). Only TS increased significantly in the 2 other groups. There were 7 cases of crankshaft phenomenon occurrence in the hybrid instrumentation group (33%), but none in the other 2 groups. These findings suggest that in skeletally immature patients with AIS, hybrid instrumentation cannot effectively prevent occurrence of the crankshaft phenomenon, whereas interval and consecutive pedicle screw instrumentation may be more (and equally) efficacious in this regard.

Derotational Casting for Progressive Infantile Scoliosis

Serial cast correction by using the Cotrel derotation technique is one of several potential treatments for progressive infantile scoliosis. This study reviews our early experience to identify which, if any, patients are likely to benefit from or fail this technique. We followed all patients treated at our institutions for progressive infantile scoliosis since 2003 prospectively at 1 institution and retrospectively at the other 2. Data, including etiology, Cobb angles, rib vertebral angle difference, Moe-Nash rotation, and space available for the lung, were recorded over time. Fifty-five patients with progressive infantile scoliosis had more than 1 year of follow-up from the initiation of casting. The diagnosis of progressive scoliosis was made based upon either a progressive Cobb angle or a rib vertebral angle difference of more than 20 degrees at presentation. All but 6 patients responded to cast correction. Nine patients have undergone surgery to date, 6 because of worsening and 3 by parent choice. As shown in the table, initiation of cast correction at a younger age, moderate curve size (<60 degrees), and an idiopathic diagnosis carry a better prognosis than an older age of initiation, curve >60 degrees, and a nonidiopathic diagnosis. The space available for the lung improved from 0.89 to 0.93. No patient experienced worsening of rib deformities. Serial cast correction for infantile scoliosis often results in full correction in infants with idiopathic curves less than 60 degrees if started before 20 months of age. Cast correction for older patients with larger curves or nonidiopathic diagnosis still frequently results in curve improvement along with improvement in chest and body shape. Derotational cast correction seems to play a role in the treatment of progressive infantile scoliosis with cures in young patients and reductions in curve size with a delay in surgery in older and syndromic patients. Level 4, therapeutic study.

Drooping of Apical Convex Rib-vertebral Angle in Adolescent Idiopathic Scoliosis of More Than 40 Degrees

It is a retrospective analysis on radiograms of 113 adolescent idiopathic scoliosis (AIS) patients with a curve of 40 degrees or more at the time of presentation. Our aim was to find out the prognostic factor for the curve progression for this group. There is general consensus in favor of operation when the curve is more than 40 degrees for AIS. There are number of reports on the prognostic and etiologic factors for the progression of scoliosis. Rib-vertebral angle (RVA) became a topic of interest regarding the progression of scoliosis for many researchers since Mehta introduced it in 1972. There were 113 AIS patients (95 females and 18 males) who had a curve of more than 40 degrees at the time of presentation, with an average age of 12 years and 10 months. We measured RVA on the convex and concave sides at the apex and 12th vertebrae and measured rib-vertebral angle difference (RVAD) using Mehta's method at each follow-up. We also measured the drooping value of the convex rib after bracing and at final follow-up. Of the 113 patients, 84 responded to bracing and in 29 the curve progressed despite bracing at final follow-up. The average drooping of rib at the apex on the convex side was 11 degrees, which progressed compared with 0.12 degrees in those who responded to treatment. On analyzing the results we could not find any relationship in 12th vertebrae but there was a significant relationship between the drooping value of convex apical rib (RVA Cx) after bracing and curve progression, which is similar to RVAD. There was no relationship between curve progression and initial angle, age, Risser sign, or menarchal status at presentation. From our study, we conclude that a large number of curves can be treated with bracing; however, when we notice drooping of the convex apical rib along with RVAD, the curve will likely progress.

Dynamic instrumentation techniques in early-onset scoliosis

Similar to the situation in idiopathic scoliosis, the decision for operative or conservative treatment is based on the progression of the curve. Apart from age and Cobb angle, the rib-vertebral angle difference and rotation of the vertebrae are decisive for the prognosis. Surgery is indicated if, despite consistent brace treatment, a progression of >10 degrees or a Cobb angle of more than 45 degrees is found. Two different dorsal dynamic systems are presently used. With the growing rod technique, one or two rods are fixed to the spine cranially and caudally and are repeatedly"lengthened." Surgery is mandatory at least every 6 months. The Orthobiom system follows a new approach in which a rigid fixation is done in the middle of the curve, while the ends of the rods are linked to flexible connectors that can slide while the child grows. No long-time results are presently available for either system, so no general recommendations can be given.

Vertebral Rotation and Thoracic Torsion in Adolescent Idiopathic Scoliosis

As a result of the increased appreciation of the three-dimensional nature of scoliosis and modern spinal instrumentation's improved corrective capabilities, there has been renewed interest in the correction and measurement of vertebral rotation. Computed tomography (CT), the gold standard for accuracy, is limited in its clinical utility owing to cost, radiation exposure, and the effects of postural changes on scoliosis curves and vertebral rotation. Consequently, the Perdriolle and Nash-Moe techniques remain the standard measurements for providing a reasonable estimate of pre- and postoperative vertebral rotation because of their simplicity. However, these techniques have considerable interobserver variability, and pedicle screw instrumentation obscures the landmarks necessary for utilizing these techniques for postoperative vertebral rotation assessment. The purpose of the present study was to assess the utility of alternate radiographic measures to assess vertebral rotation and thoracic torsion when compared with conventional measures on pre- and postoperative radiographs and CT evaluation. We reviewed the preoperative, immediate postoperative, and final follow-up radiographs, as well as the pre- and postoperative CT scans, of 19 patients (average age 15 years, 6 months) with Lenke 1 curves (average 55 degrees , range 47-66 degrees ), all treated with anterior spinal fusion. Coronal and sagittal Cobb angles as well as vertebral rotation (Perdriolle and Nash-Moe) at the superior uninstrumented, superior instrumented, apical, inferior instrumented, and inferior uninstrumented vertebrae were measured on all films, and vertebral rotation was assessed on the CT scans by a previously described method. Additionally, several measures of thoracic torsion (as a proxy for vertebral rotation and overall deformity improvement) were assessed. These included the rib-vertebral angle difference (RVAD), apical rib hump prominence (RH), apical vertebral body-rib ratio (AVB-R), and apical rib spread difference (ARSD). The postoperative main thoracic curve averaged 26 degrees (range 16-39 degrees , 52% correction) and 29 degrees (range 22-40 degrees , 47% correction) at final follow-up. For apical derotation, the postoperative CT improved from -11.5 degrees to -6.6 degrees and correlated significantly with the Cobb main thoracic curves (42% correction, r = 0.48, P = 0.003). There was weakly positive, but statistically significant, correlation between the pre- and postoperative CT scans and the corresponding Perdriolle and Nash-Moe measures of segmental rotation (r = 0.32-0.40, all P < 0.0001). The RVAD demonstrated poor correlation with the main thoracic curve values and correction, Perdriolle rotation and correction, and CT rotation and correction (r = -0.22-0.37, all P > 0.20). The apical RH demonstrated good correlation with the main thoracic curve (r = 0.65, P < 0.0001), apical Perdriolle rotation (r = 0.57, P < 0.0001), and CT apical rotation (r = 0.53, P = 0.002). We also found moderate correlation between the AVB-R and the main thoracic Cobb, apical Perdriolle, and CT (r = 0.57, 0.59, and 0.49, respectively; all P < 0.005). Similar relationships were found with the ARSD (r = 0.51, 0.47, and 0.43, respectively; all P < 0.02). The RH, AVB-R, and the ARSD-measures of thoracic torsion-demonstrated moderate to good overall correlation with the main thoracic curve Cobb angles, apical Perdriolle rotation, and apical CT rotation. These should be useful as clinical measures for assessing three-dimensional deformity correction on plane radiographs, especially for the intraoperative evaluation of vertebral derotation and thoracic symmetry restoration.

Juvenile-Onset Scoliosis Followed up to Adulthood: Orthopaedic and Functional Outcomes

This retrospective review describes 52 children with juvenile-onset scoliosis followed up for at least 2 years after skeletal maturity and completion of treatment. The purpose was to compare clinical and radiographic characteristics and curve progression, as well as orthopaedic, functional, and psychosocial outcomes in children treated by observation, bracing, or surgery. Seventeen percent of patients were treated with observation and 33% with bracing; and 50% required surgery. Median rib-vertebral angle difference and mean level of apical vertebra differed by treatment group. Neither brace nor surgical treatment negatively affected self-esteem. Results suggest that juvenile scoliosis is more likely to progress, less likely to respond to bracing, and more likely to require surgical treatment than adolescent idiopathic scoliosis.