This study addresses a crucial gap in the knowledge of normative spinal growth in children. The objective of this study is to provide detailed and accurate 3D reference values for global and segmental spinal dimensions in healthy children under the age of 11. Radiographic spine examinations of healthy children conducted to rule out scoliosis were reviewed in four scoliosis referral centers in North America. All consecutive children aged three to eleven years old with EOS biplanar good quality x-rays, but without diagnosed growth-affecting pathologies, were included. Postero-Anterior and Lateral calibrated x-rays were used for spine 3D reconstruction and computation of vertebral body height and spine length. Median and interquartile range were calculated from cross-sectional data. Smooth centiles growth curves for 3D True Spinal Length (3DTSL) between T1 and S1, as well as for mid-vertebral heights of T5, T12 and L3, where fit and calibrated from data using the Lambda-Mu-Sigma method (GAMLSS package for R). This method automatically selects the best performing distribution from a familly of choices. Tables of centiles were then predicted from the computed models for selected ages. A total of 638 full spine examinations from asymptomatic patients were reconstructed in 3D, 397 in girls and 241 in boys. Medians and interquartile ranges were calculated for 3DTSL (T1-S1): 285 (24) mm, 314 (26) mm and 349 (31) mm, and for selected vertebral heights T5: 10 (1) mm, 11 (1) mm and 12 (1) mm, T12: 13 (2) mm, 14 (1) mm and 16 (2) mm, and L3: 14 (1) mm, 16 (2) mm and 18 (2) mm, respectively for the 3–6, 6–8 and 8–11 age groups. Centile curves ready for clinical use of the 3DTSL (T1-S1) and of the vertebral heights of T5, T12 and L3 as a function of age were derived for the 5, 10, 25, 50, 75, 90 and 95th centiles. In general, boys presented linear relationships between spinal dimensions and age, and girls presented more diverging trends with increased variance for older ages. Accordingly curves for boys follow the Normal distribution whereas those for girls follow the original Box-Cox-Cole-Green distribution. Model diagnostic tests (normally distributed residuals, adequate wormplots and |Z statistics| < 2) confirmed adequacy of the models and the absence of significant misfit. Accurate reference values were derived for spinal dimensions in healthy children. Spinal dimension charts showed that the spinal lengths and vertebral heights changed relatively constantly across the age groups closely resembling WHO total body height charts. The reference values will help physicians better assess their patients' growth potential. It could also be used to predict expected spinal dimensions at maturity or changes in pathologic conditions as well as to assess the impact of growth friendly interventions in the correction of spinal deformities.
The magnetically controlled growing rod (MCGR) system allows growth maintenance without the risk of anaesthesia, implant and wound complications associated with repeated surgeries. This is a medium-term report of the complications of MCGR from a multicentre study. Twenty-six patients from 6 spine institutes that are part of a multicentre study with prospectively collected data of minimum 24 months follow-up were assessed. Pre-operative, immediate post-operative and most recent spine radiographs were reviewed to measure the Cobb angle and the rod lengthening distance. The causes and any associated risk factors for re-operations were examined. Eleven patients required re-operation within the follow-up period, with a mean time to re-operation of 17 months after the initial surgery. Five were due to failure of rod distractions; 3 were due to failure of proximal foundation implants; 2 were due to rod breakage; and one case of superficial wound infection with failure of proximal fixation. Proximal junctional kyphosis occurred in 5 patients. Three had proximal anchor dislodgement and all five constructs were revised. This is the largest series with the longest follow-up to date. Our series show that the perception that using MCGR may reduce the frequency of re-operations may not be entirely true. This is the first report to examine the need for re-operation after MCGR implantation, and highlights the inherent risks of any surgical treatment in this group of patients despite the advantages of this new implant. Longer-term studies and comparisons with traditional growing rods are required.
The Hamann-Todd collection at the Cleveland Museum of Natural History (Cleveland, OH, USA) includes 63 paediatric skeletal specimens in varying condition and completeness. The initial data collection included representative skeletons of children aged 1–18 years. The aim of this study was to better understand the growth patterns of the paediatricspine and ribs. Data from vertebrae and corresponding ribs were collected. Data included 46 measurements from the vertebral body and ribs at T1, T4, T7, T10, and L3. Measurements were obtained with Vernier calipers, tape measures, and photographs of each bone. Several specimens were digitised with a Next Engine 3D laser scanner. The initial analysis used caliper-derived data, with some measurements obtained from photographs. The data were analysed by age, specific bone, and morphological features. More than 2000 cross correlations were studied. Linear regressions were done on scalar measurements with SAS (version 9.1.3) and JMP (version 8.0). Although the general demographics for each child were known, specifics such as height and weight or previous trauma were not.Introduction
Methods
There is an unresolved controversy in the published work about the effect of screws crossing the neuro-central cartilage (NCC) on spinal canal dimension in very young children and in animals. Anterior vertebral body screws with fusion can invade and damage the NCC, especially at the site of screw insertion; however, this finding has never been studied. This study is a retrospective, clinical and radiological analysis of seven consecutive children aged 1–2 years treated with anterior vertebral instrumentation and fusion by downsized rod screw systems. The mean age at time of surgery was 2 years 4 months (range 1 year 9 months to 2 years 10 months). The average follow-up period was 3 years 3 months (2 years 6 months to 4 years 5 months). 16 screws inserted anteriorely were evaluated by a follow-up CT scan. Spinal canals were divided with known anatomical landmarks into right and left hemicanals. The relation of the anterior screws to the NCC and the spinal canal dimension were studied. All clinical and radiological complications were recorded.Introduction
Methods
Surgical correction of spinal deformities is a challenge; segmental instrumentation controlling almost every level is the most recent approach. Correction of the deformity only through apical manipulation has many potential advantages, including little tissue disruption, less invasive intervention, preservation of spinal mobility, and vertebral growth. However, quantification of the amount of force needed to pull on the apex and its effect on translation, de-rotation, and overall correction of the curve needs to be studied. The purpose of this study is to determine the effect and amount of force needed to pull on the apex of a scoliotic deformity towards the midline, and the feasibility of use of this novel potential method of correction in the treatment of patients with adolescent idiopathic scoliosis (AIS). Measurements were taken from 20 patients with AIS treated between June, 2009, and January, 2010. There were 16 female and 4 male patients with an average age of 14.2 years (range 11–20); the coronal preoperative Cobb angle was 67° (42–108°), decreasing on bending to 39° (8–83°), and the apex of the deformity was between T6 and L2. All patients had proximal and distal anchors spanning two levels on each end; the anchors were connected by a concave rod to which the apical vertebra was pulled. We measured the distance between the rod and the apical vertebra and the rotation of the apical vertebrae.Introduction
Methods
The change of position of the distal pedicle screws with growing rods in relation to vertebral bodies was described as pedicle screws migration. Pedicle screws are subjected to serial distractive forces pushing them down with every distraction; additionally there is continuous growth of the vertebral bodies during the treatment period. These two factors can affect the change of position of the pedicle screws in relation to the vertebrae during the use of growing rods. To our knowledge, this finding has never been studied, confirmed, or quantified. This is a retrospective review of the radiographs and operative notes of 23 consecutive cases of early-onset scoliosis treated with single growing rods. Age at index surgery ranged from 4 years 2 months to 8 years 9 months, and the number of distractions was four to 11 per patient. Measurements were done on post-index and latest follow-up true lateral radiographs. With optimum initial position of the screws in the pedicle, we calculated the distance between the upper end plate and the pedicle screw (distance superior to the screw [SS]) and the distance between the screw and lower-end plate (distance inferior to the screw [IS]). We expressed this ratio as a percentage: SS/IS x 100%. Any increase in this percentage with time denoted a more caudal position; however, a change in the percentage of less than 10% was regarded as insignificant.Introduction
Methods
