The MAGnetic Expansion Control (MAGEC) system is used increasingly in the management of early-onset scoliosis. Good results have been published, but there have been recent reports identifying implant failures that may be associated with significant metallosis surrounding the implants. This article aims to present the current knowledge regarding the performance of this implant, and the potential implications and strategies that may be employed to identify and limit any problems. We urge surgeons to apply caution to patient and construct selection; engage in prospective patient registration using a spine registry; ensure close clinical monitoring until growth has ceased; and send all explanted MAGEC rods for independent analysis. The MAGEC system may be a good instrumentation system for the treatment of early-onset scoliosis. However, it is innovative and like all new technology, especially when deployed in a paediatric population, robust systems to assess long-term outcome are required to ensure that patient safety is maintained. Cite this article: Bone Joint J 2017;99-B:708–13

Conventional growing rods are the most commonly used distraction-based devices in the treatment of progressive early-onset scoliosis. This technique requires repeated lengthenings with the patient anaesthetised in the operating theatre. We describe the outcomes and complications of using a non-invasive magnetically controlled growing rod (MCGR) in children with early-onset scoliosis. Lengthening is performed on an outpatient basis using an external remote control with the patient awake. Between November 2009 and March 2011, 34 children with a mean age of eight years (5 to 12) underwent treatment. The mean length of follow-up was 15 months (12 to 18). In total, 22 children were treated with dual rod constructs and 12 with a single rod. The mean number of distractions per patient was 4.8 (3 to 6). The mean pre-operative Cobb angle was 69° (46° to 108°); this was corrected to a mean 47° (28° to 91°) post-operatively. The mean Cobb angle at final review was 41° (27° to 86°). The mean pre-operative distance from T1 to S1 was 304 mm (243 to 380) and increased to 335 mm (253 to 400) in the immediate post-operative period. At final review the mean distance from T1 to S1 had increased to 348 mm (260 to 420). Two patients developed a superficial wound infection and a further two patients in the single rod group developed a loss of distraction. In the dual rod group, one patient had pull-out of a hook and one developed prominent metalwork. Two patients had a rod breakage; one patient in the single rod group and one patient in the dual rod group. Our early results show that the MCGR is safe and effective in the treatment of progressive early-onset scoliosis with the avoidance of repeated surgical lengthenings. Cite this article: Bone Joint J 2013;95-B:75–80

Aims. The aim of this study was to compare the surgical and quality-of-life outcomes of children with skeletal dysplasia to those in children with idiopathic early-onset scoliosis (EOS) undergoing growth-friendly management. Patients and Methods. A retrospective review of two prospective multicentre EOS databases identified 33 children with skeletal dysplasia and EOS (major curve ≥ 30°) who were treated with growth-friendly instrumentation at younger than ten years of age, had a minimum two years of postoperative follow-up, and had undergone three or more lengthening procedures. From the same registries, 33 matched controls with idiopathic EOS were identified. A total of 20 children in both groups were treated with growing rods and 13 children were treated with vertical expandable prosthetic titanium rib (VEPTR) instrumentation. Results. Mean preoperative major curves were 76° (34° to 115°) in the skeletal dysplasia group and 75° (51° to 113°) in the idiopathic group (p = 0.55), which were corrected at final follow-up to 49° (13° to 113°) and 46° (12° to 112°; p = 0.68), respectively. T1-S1 height increased by a mean of 36 mm (0 to 105) in the skeletal dysplasia group and 38 mm (7 to 104) in the idiopathic group at the index surgery (p = 0.40), and by 21 mm (1 to 68) and 46 mm (7 to 157), respectively, during the distraction period (p = 0.0085). The skeletal dysplasia group had significantly worse scores in the physical function, daily living, financial impact, and parent satisfaction preoperatively, as well as on financial impact and child satisfaction at final follow-up, than the idiopathic group (all p < 0.05). The domains of the 24-Item Early-Onset Scoliosis Questionnaire (EOSQ24) remained at the same level from preoperative to final follow-up in the skeletal dysplasia group (all p > 0.10). Conclusion. Children with skeletal dysplasia gained significantly less spinal growth during growth-friendly management of their EOS and their health-related quality of life was significantly lower both preoperatively and at final follow-up than in children with idiopathic EOS. Cite this article: Bone Joint J 2019;101-B:1563–1569

Aims. To report the mid-term results of a modified self-growing rod (SGR) technique for the treatment of idiopathic and neuromuscular early-onset scoliosis (EOS). Methods. We carried out a retrospective analysis of 16 consecutive patients with EOS treated with an SGR construct at a single hospital between September 2008 and December 2014. General demographics and deformity variables (i.e. major Cobb angle, T1 to T12 length, T1 to S1 length, pelvic obliquity, shoulder obliquity, and C7 plumb line) were recorded preoperatively, and postoperatively at yearly follow-up. Complications and revision procedures were also recorded. Only patients with a minimum follow-up of five years after surgery were included. Results. A total of 16 patients were included. Six patients had an idiopathic EOS while ten patients had a neuromuscular or syndromic EOS (seven spinal muscular atrophy (SMA) and three with cerebral palsy or a syndrome). Their mean ages at surgery were 7.1 years (SD 2.2) and 13.3 years (SD 2.6) respectively at final follow-up. The mean preoperative Cobb angle of the major curve was 66.1° (SD 8.5°) and had improved to 25.5° (SD 9.9°) at final follow-up. The T1 to S1 length increased from 289.7 mm (SD 24.9) before surgery to 330.6 mm (SD 30.4) immediately after surgery. The mean T1 to S1 and T1 to T12 growth after surgery were 64.1 mm (SD 19.9) and 47.4 mm (SD 18.8), respectively, thus accounting for a mean T1 to S1 and T1 to T12 spinal growth after surgery of 10.5 mm/year (SD 3.7) and 7.8 mm/year (SD 3.3), respectively. A total of six patients (five idiopathic EOS, one cerebral palsy EOS) had broken rods during their growth spurt but were uneventfully revised with a fusion procedure. No other complications were noted. Conclusion. Our data show that SGR is a safe and effective technique for the treatment of EOS in nonambulatory hypotonic patients with a neuromuscular condition. Significant spinal growth can be expected after surgery and is comparable to other published techniques for EOS. While satisfactory correction of the deformity can be achieved and maintained with this technique, a high rate of rod breakage was seen in patients with an idiopathic or cerebral palsy EOS. Cite this article: Bone Joint J 2020;102-B(11):1560–1566

Aims. The aim of this study was to compare the clinical and radiological outcomes of patients with early-onset scoliosis (EOS), who had undergone spinal fusion after distraction-based spinal growth modulation using either traditional growing rods (TGRs) or magnetically controlled growing rods (MCGRs). Methods. We undertook a retrospective review of skeletally mature patients who had undergone fusion for an EOS, which had been previously treated using either TGRs or MCGRs. Measured outcomes included sequential coronal T1 to S1 height and major curve (Cobb) angle on plain radiographs and any complications requiring unplanned surgery before final fusion. Results. We reviewed 43 patients (63% female) with a mean age of 6.4 years (SD 2.6) at the index procedure, and 12.2 years (SD 2.2) at final fusion. Their mean follow-up was 8.1 years (SD 3.4). A total of 16 patients were treated with MCGRs and 27 with TGRs. The mean number of distractions was 7.5 in the MCGR group and ten in the TGR group (p = 0.471). The mean interval between distractions was 3.4 months in the MCGR group and 8.6 months in the TGR group (p < 0.001). The mean Cobb angle had improved by 25.1° in the MCGR group and 23.2° in TGR group (p = 0.664) at final follow-up. The mean coronal T1 to S1 height had increased by 16% in the MCGR group and 32.9% in TGR group (p = 0.001), although the mean T1 to S1 height achieved at final follow-up was similar in both. Unplanned operations were needed in 43.8% of the MCGR group and 51.2% of TGR group (p = 0.422). Conclusion. In this retrospective, single-centre review, there were no significant differences in major curve correction or gain in spinal height at fusion. Although the number of planned procedures were fewer in patients with MCGRs, the rates of implant-related complications needing unplanned revision surgery were similar in the two groups. Cite this article: Bone Joint J 2022;104-B(2):257–264

Aims. We undertook a prospective non-randomised radiological study to evaluate the preliminary results of using magnetically-controlled growing rods (MAGEC System, Ellipse technology) to treat children with early-onset scoliosis. Patients and Methods. Between January 2011 and January 2015, 19 children were treated with magnetically-controlled growing rods (MCGRs) and underwent distraction at three-monthly intervals. The mean age of our cohort was 9.1 years (4 to 14) and the mean follow-up 22.4 months (5.1 to 35.2). Of the 19 children, eight underwent conversion from traditional growing rods. Whole spine radiographs were carried out pre- and post-operatively: image intensification was used during each lengthening in the outpatient department. The measurements evaluated were Cobb angle, thoracic kyphosis, proximal junctional kyphosis and spinal growth from T1 to S1. Results. The mean pre-, post-operative and latest follow-up Cobb angles were 62° (37.4 to 95.8), 45.1° (16.6 to 96.2) and 43.2° (11.9 to 90.5), respectively (p < 0.05). The mean pre-, post-operative and latest follow-up T1-S1 lengths were 288.1 mm (223.2 to 351.7), 298.8 mm (251 to 355.7) and 331.1 mm (275 to 391.9), respectively (p < 0.05). In all, three patients developed proximal pull-out of their fixation and required revision surgery: there were no subsequent complications. There were no complications of outpatient distraction. Conclusions. Our study shows that MCGRs provide stable correction of the deformity in early-onset scoliosis in both primary and revision procedures. They have the potential to reduce the need for multiple operations and thereby minimise the potential complications associated with traditional growing rod systems. Cite this article: Bone Joint J 2016;98-B:1240–47

Aims. The aim of this study was to compare outcomes after growth-friendly treatment for early-onset scoliosis (EOS) between patients with skeletal dysplasias versus those with other syndromes. Methods. We retrospectively identified 20 patients with skeletal dysplasias and 292 with other syndromes (control group) who had completed surgical growth-friendly EOS treatment between 1 January 2000 and 31 December 2018. We compared radiological parameters, complications, and health-related quality of life (HRQoL) at mean follow-up of 8.6 years (SD 3.3) in the dysplasia group and 6.6 years (SD 2.6) in the control group. Results. Mean major curve correction per patient did not differ significantly between the dysplasia group (43%) and the control group (28%; p = 0.087). Mean annual spinal height increase was less in the dysplasia group (9.3 mm (SD 5.1) than in the control group (16 mm (SD 9.2); p < 0.001). Mean annual spinal growth adjusted to patient preoperative standing height during the distraction period was 11% in the dysplasia group and 14% in the control group (p = 0.070). The complication rate was 1.6 times higher (95% confidence interval (CI) 1.3 to 2.0) in the dysplasia group. The following complications were more frequent in the dysplasia group: neurological injury (rate ratio (RR) 5.1 (95% CI 2.3 to 11)), deep surgical site infection (RR 2.2 (95% CI 1.2 to 4.1)), implant-related complications (RR 2.0 (95% CI 1.5 to 2.7)), and unplanned revision (RR 1.8 (95% CI 1.3 to 2.5)). Final fusion did not provide additional spinal height compared with watchful waiting (p = 0.054). There were no significant differences in HRQoL scores between the groups. Conclusion. After growth-friendly EOS treatment, patients with skeletal dysplasias experienced a higher incidence of complications compared to those with other syndromes. Surgical growth-friendly treatment for skeletal dysplasia-associated EOS should be reserved for patients with severe, progressive deformities that are refractory to nonoperative treatment. Cite this article: Bone Joint J 2024;106-B(6):596–602

Aims

The aim of this study was to compare the outcomes of surgery using growing rods in patients with severe versus moderate early-onset scoliosis (EOS).

Aims

To investigate metallosis in patients with magnetically controlled growing rods (MCGRs) and characterize the metal particle profile of the tissues surrounding the rod.

The December 2022 Children’s orthopaedics Roundup. 360. looks at: Immobilization of torus fractures of the wrist in children (FORCE): a randomized controlled equivalence trial in the UK; Minimally invasive method in treatment of idiopathic congenital vertical talus: recurrence is uncommon; “You’re O.K. Anaesthesia”: closed reduction of displaced paediatric forearm and wrist fractures in the office without anaesthesia; Trunk range of motion and patient outcomes after anterior vertebral body tethering versus posterior spinal fusion: comparison using computerized 3D motion capture technology; Selective dorsal rhizotomy for individuals with spastic cerebral palsy; Scheuermann’s kyphosis and posterior spinal fusion; All-pedicle-screw constructs in skeletally immature patients with severe idiopathic early-onset scoliosis; Proximal femoral screw hemiepiphysiodesis in children with cerebral palsy

The April 2024 Spine Roundup. 360. looks at: Lengthening behaviour of magnetically controlled growing rods in early-onset scoliosis: a multicentre study; LDL, cholesterol, and statins usage cause pseudarthrosis following lumbar interbody fusion; Decision-making in the treatment of degenerative lumbar spondylolisthesis of L4/L5; Does the interfacing angle between pedicle screws and support rods affect clinical outcomes after posterior thoracolumbar fusion?; Returning to the grind: how workload influences recovery post-lumbar spine surgery; Securing the spine: a leap forward with s2 alar-iliac screws in adult spinal deformity surgery

The April 2023 Children’s orthopaedics Roundup. 360. looks at: Can you treat type IIA supracondylar humerus fractures conservatively?; Bone bruising and anterior cruciate ligament injury in paediatrics; Participation and motor abilities after treatment with the Ponseti method; Does fellowship training help with paediatric supracondylar fractures?; Supracondylar elbow fracture management (Supra Man): a national trainee collaborative evaluation of practice; Magnetically controlled growing rods in early-onset scoliosis; Weightbearing restrictions and weight gain in children with Perthes’ disease?; Injuries and child abuse increase during the pandemic over 12,942 emergency admissions

Aims. Magnetically controlled growing rods (MCGR) have been gaining popularity in the management of early-onset scoliosis (EOS) over the past decade. We present our experience with the first 44 MCGR consecutive cases treated at our institution. Methods. This is a retrospective review of consecutive cases of MCGR performed in our institution between 2012 and 2018. This cohort consisted of 44 children (25 females and 19 males), with a mean age of 7.9 years (3.7 to 13.6). There were 41 primary cases and three revisions from other rod systems. The majority (38 children) had dual rods. The group represents a mixed aetiology including idiopathic (20), neuromuscular (13), syndromic (9), and congenital (2). The mean follow-up was 4.1 years, with a minimum of two years. Nine children graduated to definitive fusion. We evaluated radiological parameters of deformity correction (Cobb angle), and spinal growth (T1-T12 and T1-S1 heights), as well as complications during the course of treatment. Results. The mean Cobb angles pre-operatively, postoperatively, and at last follow-up were 70° (53 to 103), 35° (15 to 71) and 39° (15 to 65) respectively (p < 0.001). Further, there was a mean of 14° (-6 to 27) of additional Cobb angle correction upon graduation from MCGR to definitive fusion. Both T1-T12 and T1-S1 showed significant increase in heights of 27 mm and 45 mm respectively at last follow-up (p < 0.001). Ten children (23%) developed 18 complications requiring 21 unplanned operations. Independent risk factors for developing a complication were single rod constructs and previous revision surgery. Conclusion. MCGR has the benefit of avoiding multiple surgeries, and is an effective tool in treatment of early-onset scoliosis. It also maintains the flexibility of the spine, allowing further correction at the time of definitive fusion. Cite this article: Bone Joint Open 2020;1-7:405–414

Introduction. Growing rods are used in the treatment of early-onset scoliosis. The aim of this technique is to achieve deformity correction while maintaining spinal growth. Gradual stiffening or spontaneous fusion of the spine can interfere with the ability to lengthen. Furthermore, diminished acquired length with serial distraction is common and needs to be evaluated and quantified. The purpose of this prospective study was to measure the forces and amount of distraction over time in patients with early-onset scoliosis treated with growing rods. Methods. Distraction forces were measured prospectively during 60 consecutive lengthening procedures in 26 patients. All patients had single submuscular rod constructs with side-to-side connectors. For every measurement, output from a transducer on a dedicated pair of distraction calipers was recorded at zero load status, and the force was then recorded at every 1 mm lengthening; length was obtained at each event and was recorded in millimeters. Results. The force required to distract the spine doubled at the fifth lengthening procedure (mean 368 N [SD 54]), and the distraction force was significantly higher at the fifth lengthening than at previous lengthening (p<0·01). Mean length achieved at each distraction decreased over time, such that by the fifth lengthening, 8mm or less was consistently achieved. Conclusions. Distraction forces increase significantly after repeated lengthening of growing rod constructs, and the length obtained at each procedure decreases

Introduction. Sparing of the spinal growth and scoliotic deformity control in patients with early-onset scoliosis is a challenge in spinal surgery. Loss of the surgical correction, implant breakage, and revision surgeries are the main disadvantages of present treatment methods. The purpose of this study is to investigate whether growing transpedicular instrumentation spares achieved surgical correction during patient's growth. Methods. This is a prospective study of 12 consecutive patients with early-onset scoliosis from one clinical centre. All patients underwent anterior convex growth arrest and posterior transpedicular instrumentation with growing construct. Spinal derotation was used for the correction of the deformity. The diagnoses were infantile idiopathic (n=10) and congenital (n=2) scoliosis (formation failure). Follow-up was 3 years. Mean age at the time of surgery was 9·1 years. Results. Preoperative major Cobb angle was 74·3° (range 52–100°), minor Cobb angle was 32·2° (5–50°), and average preoperative thoracic kyphosis was 27·2° (0–63°). Mean number of the instrumented levels was 12·2. Postoperative major Cobb angle was 22·4° (0–40°), minor Cobb angle was 5·7° (0–23·5°), and postoperative thoracic kyphosis was 26·2° (6–41°). After 3 years of follow-up, primary curve was an average of 22·7° (10–40°), secondary curve was 5·4° (0–25°), and mean thoracic kyphosis was 28° (12–40°). Mean growth of the instrumented spine was 18 mm. We did not observe any gross complications in the patients. Two patients had pleural effusion, and one needed rod exchange 15 months after primary surgery because of insufficient length. Conclusions. The results of this study show that anterior convex growth arrest and polysegmental transpedicular spinal instrumentation with growing construct save spinal growth and anatomical values achieved after surgical correction. Rod derotation for the deformity correction favours spinal growth in skeletally immature patients

SUMMARY. A retrospective cohort study of 19 patients of EOS who underwent MCGR rod instrumentation with subsequent serial distractions, measured using ultrasonography. The degree of distraction achieved during each session were analyzed and subgroup analysis done. HYPOTHESIS. The degree of distraction/ distractibility of the MCGR rod is closely linked to the etiology of EOS. The degree of distraction achieved at each session progressively diminishes with successive distractions. STUDY DESIGN. Retrospective cohort study. INTRODUCTION. MCGR rods have gained popularity as an alternative to traditional growing rods for the treatment of Early-onset scoliosis (EOS), serially distracting with an aim to mimic the normal spinal growth, which can be achieved in an outpatient setting using external remote controller. The use of ultrasound as a tool to measure the degree of distraction achieved has been validated previously. However the association between the etiological diagnosis of EOS and the degree of distraction achieved has not been studied previously. METHODS. We performed a retrospective cohort study of 19 patients with EOS of varying etiologies who underwent MCGR rod instrumentation at our institution since 2016. Their hospital records were analyzed to assess the demographics, distraction interval and the degree of distraction achieved at each session. RESULTS. 19 patients (12 females and 7 males) were included in the study. The average age of the study population was 7 years (4–13 years). The average follow up was 2.1 years (1–4). The following were the etiological diagnoses: Idiopathic EOS(8), Neuromuscular scoliosis(5), Syndromic(5), Congenital(1). The average interval between each distraction was 109.8days (88.2–140.6). The overall mean distraction was 1.66mm (0.6–3.427). The mean distraction achieved for the concave rod was 1.69mm (0.6–3.03) as against 1.59mm (0.2–3.427) for the convex rod. The degree of distraction achieved per session was the greatest in patients with neuromuscular scoliosis 2.79mm (0.94–4.62), while it was the least in Congenital scoliosis 0.99mm (0.8–2.93). The degree of distraction in Syndromic and Idiopathic scoliosis groups were 2.19mm (0.1–4.2) and 1.50mm (0.2–4.45) respectively. The mean distraction achieved during the first session after MCGR instrumentation was 2.82mm (0.4–9.8) as against 1.98mm (0.1–4.2) and 1.18mm (0.2–2.3), achieved during the 5. th. and 10. th. distractions respectively. CONCLUSIONS. The average distraction of the MCGR rod achieved per session depends upon the etiological diagnosis of EOS. Neuromuscular curves are the most amenable to MCGR distractions, while the congenital curves are the least. The degree of distraction achieved progressively diminishes with each successive distractions. The distraction achieved slumps to 70% of the initial distraction by the 5. th. session and further declines to 41% of the initial distraction by the 10. th. session. TAKE HOME MESSAGE. The distractibility of the MCGR rod is closely linked to the etiology of EOS. MCGR rods are most effective in cases of neuromuscular scoliosis, while least effective in congenital scoliosis. The law of diminishing returns holds true even with MCGR rods

Introduction. Many methods are available for distal anchoring of spine-based and rib-based growing rod systems for early-onset scoliosis. One of these methods, pelvic S-hooks, was initially recommended for patients with spina bifida or for those with severe thoracolumbar curves. No study has yet analysed the clinical and radiographic effects of S-hooks on patients with rib-based instrumentation. The purpose of this study is to retrospectively review the results of S-hook pelvic fixation in patients with rib-based instrumentation. Methods. A multicentre, retrospective study, approved by the institutional review board, was undetaken in all patients treated with rib-based constructs using S-hooks for pelvic fixation. Preoperative and postoperative clinical variables, radiological measurements, and the incidence and management of complications were evaluated in patients with a minimum follow-up of 2 years. Results. 44 patients, 26 of whom were girls, were studied and had a mean age at surgery of 71 months. The most common surgical indication was progressive neuromuscular scoliosis. The average preoperative Cobb angle was 64° and at most recent follow-up (mean 45 months) was 53°. The most common construct was dual rods resting over the iliac crest without suture to the iliac crest extending from T3/T4 ribs to the pelvis using domino connectors. 45% of the patients had complications, of which S-hook migration after the initial procedures was the most common. S-hook migration was corrected at the next lengthening with repositioning of the hook to the iliac crest. No correlation was detected between the complication rates and the clinical, radiographic, and surgical technique variables evaluated. Conclusions. Control of spinal deformities without fusion presents several challenges. S-hooks can migrate off the iliac crest, requiring repositioning of implants during subsequent lengthening. This finding highlights the need to explore different fixation techniques with a stronger attachment to the iliac crest

Introduction. Spinopelvic parameters describe the orientation, shape, and morphology of the spine and pelvis. In children without spinal deformity, these parameters change during the first 10 years of life; however, spinopelvic parameters need to be defined in children with significant early-onset scoliosis (EOS). The purpose of this study is to examine the effects of EOS on sagittal spinopelvic alignment. We hypothesise that sagittal spinopelvic parameters for patients with EOS will differ from age-matched children without spinal deformity. These values will act as a baseline for future studies and may predict postoperative complications such as proximal junctional kyphosis and implant failure in children being treated with growing systems. Methods. Standing, lateral radiographs of 82 untreated patients with EOS with Cobb angle greater than 50° were evaluated. Sagittal spine parameters (sagittal balance, thoracic kyphosis [TK], lumbar lordosis [LL]) and sagittal pelvic parameters (pelvic incidence [PI], pelvic tilt [PT], sacral slope [SS], and modified pelvic radius angle [PR]) were measured. These results were compared with those reported by Mac-Thiong and colleagues (Spine, 2004) for a group of similar aged children without spinal deformity. Results. Patients had a mean age of 5·17 years and mean Cobb angle of 73·3° (□}17·3°). Mean sagittal spine parameters were: sagittal balance (+2·4 cm [□}4·03]), TK (38·2° [□}20·8°]), and LL (47·8° [□}17·7°]). These values were similar to those reported for asymptomatic patients (table). Mean sagittal pelvic parameters were: PI (47·1° [□}15·6°]), PT (10·3° [□}10·7°]), SS (35·5° [□}12·2°]), and PR (57·1° [□}21·2°]). Although PI was similar to age-matched controls, PT was significantly higher and there was a trend for lower SS in the study population. Conclusions. Sagittal plane spine parameters in children with EOS were similar to those in children without spinal deformity. Pelvic parameters (PI, SS, PR) were similar between groups; however, children with EOS had signs of pelvic retroversion (increased pelvic tilt)

Introduction. Spinopelvic parameters describe the orientation, shape, and morphology of the spine and pelvis. These parameters change during the first 10 years of life in children without spinal deformity; however, spinopelvic parameters have yet to be defined in children with significant early-onset scoliosis (EOS). Sagittal plane alignment could affect the natural history and outcome of interventions for EOS. As a result, spinopelvic parameters are being defined for this population. On the basis of the landmarks used for measurement of these parameters, there may be inherent error in performing these measurements on the immature pelvis. The purpose of this study is to define the variability associatedwith the measurement of spinopelvic parameters in children with EOS. Methods. Standing, lateral radiographs of 11 patients with untreated EOS were evaluated. Sagittal spinopelvic parameters (pelvic incidence [PI], pelvic tilt [PT], sacral slope [SS], and modified pelvic radius angle [PR]) were measured. To assess intraobserver reliability, these measurements were repeated 15 days apart. To define interobserver reliability, radiographs were measured by 2 independent observers. Results. Average age was 5·7 years and average Cobb angle was 80·8°. Repeated measurements by one observer showed no significant differences for any of the parameters. Paired samples correlations showed a moderate correlation between measurements of PI (0·564), whereas stronger correlations were demonstrated for measurements of PT (0·816), SS (0·947), and PR (0·789). Interobserver analysis showed a significant difference in measurement of SS (p=0·003), whereasmeasurements of PI, PT, and PR did not differ significantly between independent observers. Conclusions. Intraobserver variabilty yielded acceptable correlations for PT, SS, and PR; however, we noted only a moderate correlation for PI. Interobserver analysis showed a significant difference only in SS. The intraobserver and interobserver variablity of measurements for PT and PR were superior than were those for PI and SS. This finding may be related to difficulties in determining the orientation of the sacral endplate in the immature pelvis when measuring PI and SS

Introduction. Children with early-onset scoliosis (EOS) with rib hump chest-wall distortion or fused/absent ribs have thoracic insufficiency syndrome (TIS). Commonly, respiration is adversely affected by loss of lung volume from chest-wall constriction and clinical loss of active rib cage expansion. The dynamic thoracic components of diaphragm or rib cage lung expansion during respiration is poorly characterised by radiograph or CT scan. Pulmonary function tests indicate only hemithorax performance. Dynamic lung MRI, however, can visualise both chest-wall and diaphragm motion, allowing assessment of each individual hemithorax performance, so that a dynamic classification system of the thoracic function can be developed. Methods. Ten patients with TIS underwent dynamic lung MRI testing as part of the routine clinical preoperative work-up. Each hemithorax was graded: 1=intact motion of both chest wall and diaphragm; 2=primarily loss of chest-wall motion with minimal diaphragm abnormality; 3=substantial loss of diaphragm excursion with minimal loss or compensatory hyperkinesis of chest wall; and 4=substantial loss of both diaphragm and chest-wall motion. The grades for each hemithorax were added and averaged to form the thoracic function score. Ranges of scores were grouped into levels of clinical thoracic performance: level I (score 1–1·5); level II (>1·5–2·5); level III (>2·5–3·5); and level IV(>3·5–4·0). Results. Of nine patients with EOS, two were level I, three were level II, and four were level III. In four patients there was marked posterior obstruction of diaphragmatic excursion by soft-tissue organs. One patient with hypoplastic thorax without scoliosis was level II. Conclusions. Thoracic function index is a new thoracic performance approach based on dynamic lung MRI that has potential to identify biomechanical abnormalities of the thorax in EOS that cause restrictive lung disease. This index could provide insight into how to reverse the abnormality with new types of surgeries. Posterior obstructive blockade of the diaphragm is identified as a new cause for restrictive lung disease in EOS