Thoracic insufficiency syndrome and exotic scoliosis

Kyphectomy followed by self-sliding pedicle screw and translumbosacral rod impaction and fixation: a novel growth-friendly technique in myelomeningocele patients

INTRODUCTION

Congenital lumbar kyphosis is present in about 15% of patients with myelomeningocele. Worsening of deformity with complications such as chronic skin ulcers and bone exposure is common. In patients under 8 years of age, treatment becomes even more challenging: in addition to resecting the apex of the kyphotic deformity, we should ideally stabilize the spine with fixation methods that do not interrupt the growth of the rib cage, associated with the challenging pelvic fixation in this population. The emergence of growth-friendly techniques has greatly benefited patients with early-onset deformity, allowing for correction and control of deviation without interrupting trunk growth, which is often already compromised in these patients. We describe the surgical technique and present preliminary clinical outcomes for a novel approach which combines self-sliding screws that allow for trunk growth with impaction of translumbosacral rods for distal fixation.

METHODOLOGY

Candidates for the technique were patients with myelomeningocele and congenital lumbar kyphosis, inability to assume supine position, and a history of skin ulcers, recurrent osteomyelitis and poor weight gain. They all lacked sensory or motor function below the level of the myelomeningocele. They underwent the same reconstruction technique after kyphectomy which combines self-sliding screws that allow for trunk growth with impaction of the translumbosacral rods for distal fixation.

RESULTS

Case 1: Female; 4.5 years old at surgery; 5 year follow-up. 1 complication: loosening of one blocker. The child is doing well and did not require surgical revision. Mean growth per year: 9.5 mm. Case 2: Male; 7.4 Years old at surgery; 4 year follow-up. 1 complication: post-surgical infection which required 2 debridements in the operating room and prolonged antibiotic therapy. Mean growth per year: 6 mm. Case 3: Female; 5.5 Years old at surgery; 27 month follow-up. No complications reported so far. Mean growth per year: 9.42 mm. None of the cases showed signs of sacral osteolysis or rod migration.

DISCUSSION / CONCLUSION

To our knowledge, this is the first study that combines sliding screws with translumbosacral rod impaction. Although this technique has proven to be safe and effective, we are aware that the number of cases is limited and the follow-up is short. Further studies are necessary to confirm the method.

Comprehensive spinal correction rehabilitation (CSCR) study: a randomised controlled trial to investigate the effectiveness of CSCR in children with early-onset idiopathic scoliosis on spinal deformity, somatic appearance, functional status and quality of life in Shanghai, China

INTRODUCTION

Presently, the physiotherapy scoliosis-specific exercise recommended by the International Scientific Society on Scoliosis Orthopaedic and Rehabilitation Treatment guidelines is primarily advised for adolescents with scoliosis, and there is a lack of individualised and precise exercise therapy for children with early-onset idiopathic scoliosis (EOIS), whose bodies are in the nascent stages of development. Therefore, this study aims to investigate the efficacy of comprehensive spinal correction rehabilitation in treating EOIS.

METHODS AND ANALYSIS

This study will be designed as a randomised controlled trial, and the subjects participating in the study will consist of 122 EOIS patients between the ages of 7-10 years. Subjects will be randomly assigned to an experimental group (n=61) and a control group (n=61). Both groups will be treated for 6 months, with the experimental group receiving comprehensive spinal correction rehabilitation (including specific exercise therapy, balance and stability training, breathing training, strength training, home-based exercise and bracing) and the control group receiving core stability training. Enrolled subjects will be evaluated at the initial visit and after 6 months of treatment, and data will be processed and analysed after collecting data from both evaluations. The primary outcome index is the major curvature Cobb angle, and the secondary outcome indices are the angle of trunk rotation, plumb line distance, the Trunk Aesthetic Clinical Evaluation index, forced vital capacity and the Scoliosis Research Society-22 questionnaire.

ETHICS AND DISSEMINATION

The current study received ethical approval from the Xinhua Hospital Ethics Committee Affiliated to Shanghai Jiao Tong University School of Medicine (XHEC-C-2023-108-3). Written informed consent will be obtained from all participants and their guardians. Any interim analyses and full results will be published in an international peer-reviewed journal.

TRIAL REGISTRATION NUMBER

The study protocol was registered at www.

CLINICAL TRIALS

gov (number identifier: ChiCTR2300078359).

Variation in thoracic inlet measurements and its correlation with pulmonary dysfunction in kyphoscoliotic deformities: a prospective case-control study

BACKGROUND

Pulmonary dysfunction in thoracic kyphoscoliosis has been correlated with chest wall distortion, uneven trunk growth and restrictive pattern. The study aims to analyse the variation in thoracic inlet measurements on pulmonary dysfunction with varying curve magnitude and thoracic cage parameters.

METHODS

In a non-randomised, prospective case-control study, 80 consecutive patients with thoracic kyphoscoliosis were divided into 3 groups based on Cobb angle: Group 1 (31-50), Group 2 (51-80) and Group 3 (> 80). Thoracic inlet measurement was calculated by thoracic inlet index (TI) on MRI at the sternal level. Pulmonary function and thoracic cage parameters [hemi thorax height, rib-apex distance, AP chest diameter at sternal level and transverse thoracic diameter] were documented. TI values were compared with 20 age-matched asymptomatic controls. Multivariate correlation and regression analysis were performed to investigate the correlations.

RESULTS

The mean age of the study cohort was 14.1 ± 4.4 years, including Group 1 (6 patients), Group 2 (55 patients) and Group 3 (19 patients) versus 12.9 ± 2.2 years in controls. The mean TI was 2.8 ± 0.56 in Group 1, 3.7 ± 0.9 in Group 2 and 4.0 ± 1.12 in Group 3 versus 2.6 ± 0.43 in controls. Pulmonary dysfunction was severe with TI > 7.1 (p < 0.001) in Group 3 patients with thoracic hypokyphosis. Multivariate regression for thoracic parameters and TI > 5.6 showed significant correlation of pulmonary dysfunction in Group 2 and 3 curves with apex between T1 and T4, whereas transverse thoracic diameter, rib-apex distance and hemi thorax height were weakly associated.

CONCLUSION

Thoracic inlet index (TI), a neglected pre-operative variable associated with pulmonary dysfunction in thoracic kyphoscoliosis, can be evaluated on MRI without an additional cost and radiation.

LEVEL OF EVIDENCE: 3

Quantifying Normal Diaphragmatic Motion and Shape and their Developmental Changes via Dynamic MRI

Background

The diaphragm is a critical structure in respiratory function, yet in-vivo quantitative description of its motion available in the literature is limited.

Research Question

How to quantitatively describe regional hemi-diaphragmatic motion and curvature via free-breathing dynamic magnetic resonance imaging (dMRI)?

Study Design and Methods

In this prospective cohort study we gathered dMRI images of 177 normal children and segmented hemi-diaphragm domes in end-inspiration and end-expiration phases of the constructed 4D image. We selected 25 points uniformly located on each 3D hemi-diaphragm surface. Based on the motion and local shape of hemi-diaphragm at these points, we computed the velocities and sagittal and coronal curvatures in 13 regions on each hemi-diaphragm surface and analyzed the change in these properties with age and gender.

Results

Our cohort consisted of 94 Females, 6-20 years (12.09 + 3.73), and 83 Males, 6-20 years (11.88 + 3.57). We observed velocity range: ∼2mm/s to ∼13mm/s; Curvature range -Sagittal: ∼3m -1 to ∼27m -1 ; Coronal: ∼6m -1 to ∼20m -1 . There was no significant difference in velocity between genders, although the pattern of change in velocity with age was different for the two groups. Strong correlations in velocity were observed between homologous regions of right and left hemi-diaphragms. There was no significant difference in curvatures between genders or change in curvatures with age.

Interpretation

Regional motion/curvature of the 3D diaphragmatic surface can be estimated using free-breathing dynamic MRI. Our analysis sheds light on here-to-fore unknown matters such as how the pediatric 3D hemi-diaphragm motion/shape varies regionally, between right and left hemi-diaphragms, between genders, and with age.

Do Rib-Based Anchors Impair Chest Wall Motion in Early Onset Scoliosis (EOS)?

Purpose

There is a concern in pediatric surgery practice that rib-based fixation may limit chest wall motion in early onset scoliosis (EOS). The purpose of this study is to address the above concern by assessing the contribution of chest wall excursion to respiration before and after surgery.

Methods

Quantitative dynamic magnetic resonance imaging (QdMRI) is performed on EOS patients (before and after surgery) and normal children in this retrospective study. QdMRI is purely an image-based approach and allows free breathing image acquisition. Tidal volume parameters for chest walls (CWtv) and hemi-diaphragms (Dtv) were analyzed on concave and convex sides of the spinal curve. EOS patients (1-14 years) and normal children (5-18 years) were enrolled, with an average interval of two years for dMRI acquisition before and after surgery.

Results

CWtv significantly increased after surgery in the global comparison including all EOS patients (p < 0.05). For main thoracic curve (MTC) EOS patients, CWtv significantly improved by 50.24% (concave side) and 35.17% (convex side) after age correction (p < 0.05) after surgery. The average ratio of Dtv to CWtv on the convex side in MTC EOS patients was not significantly different from that in normal children (p=0.78), although the concave side showed the difference to be significant.

Conclusion

Chest wall component tidal volumes in EOS patients measured via QdMRI did not decrease after rib-based surgery, suggesting that rib-based fixation does not impair chest wall motion in pediatric patients with EOS.

Case report: A simple and reliable approach for progressive internal distraction of the sternum for Jeune syndrome (asphyxiating thoracic dystrophy): preliminary experience and literature review of surgical techniques

Background

Described for the first time in 1954, Jeune syndrome (JS), often called asphyxiating thoracic dystrophy, is a congenital musculoskeletal disease characterized by short ribs, a narrow thorax, and small limbs. In this study, we analyzed and presented our preliminary experience with a device for progressive internal distraction of the sternum (PIDS) in patients with symptomatic JS. In addition, we reviewed the contemporary English literature on existing surgical techniques for treating children with congenital JS.

Material and methods

A retrospective analysis of pediatric patients (<18 years old) treated for symptomatic JS at our tertiary center between 2017 and 2023 was performed.

Results

We presented two patients with JS who underwent surgery using an internal sternal distractor, a Zurich II Micro Zurich Modular Distractor, placed at the corpus of the sternum among the divided halves.

Conclusions

We obtained promising results regarding the safety and effectiveness of this less-invasive device for PIDS in patients with symptomatic JS. Further studies on long-term outcomes are needed to validate these findings.

Accuracy of 3D printed spine models for pre-surgical planning of complex adolescent idiopathic scoliosis (AIS) in spinal surgeries: a case series

Adolescent idiopathic scoliosis (AIS) is a noticeable spinal deformity in both adult and adolescent population. In majority of the cases, the gold standard of treatment is surgical intervention. Technological advancements in medical imaging and 3D printing have revolutionised the surgical planning and intraoperative decision making for surgeons in spinal surgery. However, its applicability for planning complex spinal surgeries is poorly documented with human subjects. The objective of this study is to evaluate the accuracy of 3D printed models for complex spinal deformities based on Cobb angles between 40° to 95°.This is a retrospective cohort study where, five CT scans of the patients with AIS were segmented and 3D printed for evaluating the accuracy. Consideration was given to the Inter-patient and acquisition apparatus variability of the CT-scan dataset to understand the effect on trueness and accuracy of the developed CAD models. The developed anatomical models were re-scanned for analysing quantitative surface deviation to assess the accuracy of 3D printed spinal models. Results show that the average of the root mean square error (RMSE) between the 3DP models and virtual models developed using CT scan of mean surface deviations for the five 3d printed models was found to be 0.5±0.07 mm. Based on the RMSE, it can be concluded that 3D printing based workflow is accurate enough to be used for presurgical planning for complex adolescent spinal deformities. Image acquisition and post processing parameters, type of 3D printing technology plays key role in acquiring required accuracy for surgical applications.

Assessment of Regional Functional Effects of Surgical Treatment in Thoracic Insufficiency Syndrome via Dynamic Magnetic Resonance Imaging

BACKGROUND

Quantitative regional assessment of thoracic function would enable clinicians to better understand the regional effects of therapy and the degree of deviation from normality in patients with thoracic insufficiency syndrome (TIS). The purpose of this study was to determine the regional functional effects of surgical treatment in TIS via quantitative dynamic magnetic resonance imaging (MRI) in comparison with healthy children.

METHODS

Volumetric parameters were derived via 129 dynamic MRI scans from 51 normal children (November 2017 to March 2019) and 39 patients with TIS (preoperatively and postoperatively, July 2009 to May 2018) for the left and right lungs, the left and right hemi-diaphragms, and the left and right hemi-chest walls during tidal breathing. Paired t testing was performed to compare the parameters from patients with TIS preoperatively and postoperatively. Mahalanobis distances between parameters of patients with TIS and age-matched normal children were assessed to evaluate the closeness of patient lung function to normality. Linear regression functions were utilized to estimate volume deviations of patients with TIS from normality, taking into account the growth of the subjects.

RESULTS

The mean Mahalanobis distances for the right hemi-diaphragm tidal volume (RDtv) were -1.32 ± 1.04 preoperatively and -0.05 ± 1.11 postoperatively (p = 0.001). Similarly, the mean Mahalanobis distances for the right lung tidal volume (RLtv) were -1.12 ± 1.04 preoperatively and -0.10 ± 1.26 postoperatively (p = 0.01). The mean Mahalanobis distances for the ratio of bilateral hemi-diaphragm tidal volume to bilateral lung tidal volume (BDtv/BLtv) were -1.68 ± 1.21 preoperatively and -0.04 ± 1.10 postoperatively (p = 0.003). Mahalanobis distances decreased after treatment, suggesting reduced deviations from normality. Regression results showed that all volumes and tidal volumes significantly increased after treatment (p < 0.001), and the tidal volume increases were significantly greater than those expected from normal growth for RDtv, RLtv, BDtv, and BLtv (p < 0.05).

CONCLUSIONS

Postoperative tidal volumes of bilateral lungs and bilateral hemi-diaphragms of patients with TIS came closer to those of normal children, indicating positive treatment effects from the surgical procedure. Quantitative dynamic MRI facilitates the assessment of regional effects of a surgical procedure to treat TIS.

LEVEL OF EVIDENCE

Diagnostic Level II. See Instructions for Authors for a complete description of levels of evidence.

A minimally interactive method for labeling respiratory phases in free-breathing thoracic dynamic MRI for constructing 4D images

OBJECTIVE

Determination of end-expiration (EE) and end-inspiration (EI) time points in the respiratory cycle in free-breathing slice image acquisitions of the thorax is one key step needed for 4D image construction via dynamic magnetic resonance imaging. The purpose of this paper is to realize the automation of the labeling process.

METHODS

The diaphragm is used as a surrogate for tracking respiratory motion and determining the state of breathing. Regions of interest (ROIs) containing the hemi-diaphragms are set by human interaction to compute the optical flow matrix between two adjacent 2D time slices. Subsequently, our approach examines the diaphragm speed and direction and by considering the change in the optical flow matrix, the EE or EI points are detected.

RESULTS AND CONCLUSION

The labeling accuracy for the lateral aspect of the left lung and the lateral aspect of the right lung (0.630.71) is significantly lower (P < 0.05) than the accuracy for other positions (0.420.44), but the error in almost all scenarios is less than 1 time point. By comparing between automatic and manual labeling in 12 scenarios, we found out that 9 scenarios showed no significant difference (P > 0.05) between two methods. Overall, our method is found to be highly agreeable with manual labeling and greatly shortens the labeling time, requiring less than 8 minutes/ study compared to 4 hours/ study for manual labeling.

SIGNIFICANCE

Our method achieves automatic labeling of EE and EI points without the need for use of patient internal or external markers.

Two-staged posterior osteotomy surgery in complex and rigid congenital scoliosis in younger than 10 years old children

Background

Congenital scoliosis caused by failure of multiply vertebral segmentation with concave fused rib or unsegmented bar combined with contralateralhemivertebra is usually rigid and produces enormous asymmetric growth. Fusionless techniques have less advantage and come with some complications. Paucity of data was reported for children with complex congenital scoliosis using two-staged osteotomy surgery.

Methods

From 2006 to 2016, 11 patients less than 10 years old undergoing two staged osteotomy surgery for complex rigid congenital scoliosis were retrospectively reviewed. The analysis included age at initial surgery, second surgery and at the latest follow-up, and complications. Changes in coronal major curve, thoracic kyphosis, lumbar lodorsis, apex vertebra translation, T1-T12 length, T1-S1 length, trunk shift, and SVAwere included in radiological evaluation.

Results

In all, the mean follow-up was 72.5 ± 23.8 (42 to 112) months. The mean flexibility of the spine was 17.4 and 17.8 % before two surgeries. The mean age at the initial surgery was 6.6 ± 2.6 (2.5–10) years. The mean fusion level was 4.6 ± 1.3 (2 to 6) segments. The mean scoliosis improved from 67.4° to 23.7° after initial surgery and was 17.4° at the latest follow-up. The average increase of T1-S1 length was 0.92 cm per year. No patients had neurological complications.

Conclusions

Two-staged osteotomy surgery including hemivertebrae resection or Y-shaped osteotomy can achieve good radiological and clinical outcomes without severe complications. This procedure can be an option of treatment for complex congenital scoliosis.

Correlation of Pulmonary Function to Novel Radiographic Parameters of Collapsing Parasol Deformity in Spinal Muscular Atrophy

Spinal muscular atrophy (SMA) is a neuromuscular disease with manifestations of scoliosis, pulmonary function decline, and, uniquely, collapse of the ribs. Methods to quantify rib deformity and its impact on pulmonary function are sparse. The authors propose new radiographic measurements to quantify the aspect of SMA known as collapsing parasol deformity and correlate these measurements with pulmonary function. Twenty-eight full-spine radiographs of pediatric SMA patients were measured twice by 3 independent investigators, with 2 weeks separating each measurement. Radiographic measurements, demographics, spirometry results, and assisted ventilation rating were obtained. Twenty-one patients with spirometry metrics were assessed to correlate pulmonary function and spinal measurements. The intrarater intraclass correlation coefficient (ICC) for the measurements ranged from 0.706 to 0.99, and the interrater ICC ranged from 0.64 to 0.97. Eighteen of 19 variables had ICC values greater than 0.75 for inter- and intrarater reliability. Twenty-one patients with forced expiratory volume in 1 second and forced vital capacity were assessed in terms of these measurements. Ratio of the concave hemithoracic width at T6/convex hemithoracic width at T6 (P=.004) and ratio of convex vertical rib displacement at the apical rib/concave vertical rib displacement (P=.021) were both significantly correlated with decreased pulmonary function. No significant correlation was found examining the average vertical rib displacement at the apical rib. High inter-and intrarater reliability can be obtained in a variety of spinal measurements of SMA patients. Various measurements are correlated to diminished pulmonary function, specifically variables showing asymmetric changes in the chest cavity. [Orthopedics. 2021;44(2):e287-e293.].

Anesthesia for Innovative Pediatric Surgical Procedures

Over the past few decades, there have been many advances in pediatric surgery, some using new devices (eg, VEPTR, MAGEC rods) and others using less invasive approaches (eg, Nuss procedure, endoscopic cranial suture release, minimally invasive tethered cord release). Although many of these procedures were initially met with caution or skepticism, continued experience over the past few decades has shown that these procedures are safe and effective. This article reviews the anesthetic considerations for these conditions and procedures.

OFx: A method of 4D image construction from free-breathing non-gated MRI slice acquisitions of the thorax via optical flux

PURPOSE

Since real-time 4D dynamic magnetic resonance imaging (dMRI) methods with adequate spatial and temporal resolution for imaging the pediatric thorax are currently not available, free-breathing slice acquisitions followed by appropriate 4D construction methods are currently employed. Self-gating methods, which extract breathing signals only from image information without any external gating technology, have much potential for this purpose, such as for use in studying pediatric thoracic insufficiency syndrome (TIS). Patients with TIS frequently suffer from extreme malformations of the chest wall, diaphragm, and spine, leading to breathing that is very complex, including deep or shallow respiratory cycles. Existing 4D construction methods cannot perform satisfactorily in this scenario, and most are not fully automatic, requiring manual interactive operations. In this paper, we propose a novel fully automatic 4D image construction method based on an image-derived concept called flux to address these challenges.

METHODS

We utilized 25 dMRI data sets from 25 pediatric subjects with no known thoracic anomalies and 58 dMRI data sets from 29 patients with TIS where each patient had a dMRI scan before and after surgery. A time sequence of 80 slices are acquired at each sagittal location continuously at a rate of ~480 ms per slice under free-breathing conditions, with 30-40 sagittal locations across the chest for each subject depending on the thoracic size. In our approach, we first extract the breathing signal for each sagittal location based on the flux of the optical flow vector field of the body region from the image time series. Here, for each time point of respiratory phase, the net flux of the body region can be regarded as the flux going into or out of the body region, which we term Optical Flux (OFx). OFx provides a very robust representation of the real breathing motion of the thorax. OFx allows us to perform a full analysis of all respiratory cycles, extract only normal cycles in a robust manner, and map all extracted normal cycles on to one cosine respiration model for each sagittal location. Subsequently, we re-sample one normal cycle from the respiration model for each location independently. The normal cycle models associated with the different sagittal locations are finally composited to form the final constructed 4D image.

RESULTS

We employ several metrics to evaluate the quality of the 4D construction results: E_ie - error in locating time instants corresponding to end inspiration and end expiration; E_to - deviation from correct temporal order in each detected normal cycle; E_ss - deviation in spatial smoothness; and E_sc - deviation from spatial continuity as scored by a reader. The means and standard deviations of these metrics for normal subjects and TIS patients are found to be, respectively: E_ie: 0.25 ± 0.05 and 0.38 ± 0.16 in units of time instance (ideal value = 0); E_to: 2.7% ± 2.3% and 1.8% ± 2% (ideal value = 0%); E_ss: 0.5 ± 0.17 and 0.54 ± 0.25 in pixel units (ideal value = 0); E_sc: 4.6 ± 0.48 and 4.56 ± 0.98 (score range: best = 5, worst = 1). The results show that the OFx method achieves excellent spatial and temporal continuity and its yield was 100% meaning that it successfully performed 4D construction on every data set tested. Compared to a recently published method, OFx is fully automatic requiring about 5 min of computational time per study starting from acquired dMRI scans. The method achieves high temporal and spatial continuity even on complex TIS data sets that include many abnormal respiratory cycles.

CONCLUSIONS

A new 4D dMRI construction method based on the concept of optical flux is presented which is fully automatic and very robust in deriving respiratory signals purely from dynamic image sequences even when presented with complex breathing patterns due to severe disease conditions like TIS. Evaluations show that its accuracy is comparable to the variations found in manual annotations. An important characteristic of the method is that it is independent of the number of sagittal locations used in the construction process, which suggests that it is applicable to imaging techniques where data are acquired at only a few sagittal locations instead of the full width of the thorax. The method is not tied to any specific imaging modality, as demonstrated in this paper on not just dMRI but dynamic computed tomography (CT) as well.

Automatic labeling of respiratory phases and detection of abnormal respiratory signals in free-breathing thoracic dynamic MR image acquisitions based on deep learning

4D thoracic images constructed from free-breathing 2D slice acquisitions based on dynamic magnetic resonance imaging (dMRI) provide clinicians the capability of examining the dynamic function of the left and right lungs, left and right hemi-diaphragms, and left and right chest wall separately for thoracic insufficiency syndrome (TIS) treatment [1]. There are two shortcomings of the existing 4D construction methods [2]: a) the respiratory phase corresponding to end expiration (EE) and end inspiration (EI) need to be manually identified in the dMRI sequence; b) abnormal breathing signals due to non-tidal breathing cannot be detected automatically which affects the construction process. Since the typical 2D dynamic MRI acquisition contains ~3000 slices per patient, handling these tasks manually is very labor intensive. In this study, we propose a deep-learning-based framework for addressing both problems via convolutional neural networks (CNNs) [3] and Long Short-Term Memory (LSTM) [4] models. A CNN is used to extract the motion characteristics from the respiratory dMRI sequences to automatically identify contiguous sequences of slices representing exhalation and inhalation processes. EE and EI annotations are subsequently completed by comparing the changes in the direction of motion of the diaphragm. A LSTM network is used for detecting abnormal respiratory signals by exploiting the non-uniform motion feature sequence of abnormal breathing motions. Experimental results show the mean error of labeling EE and EI is ~0.3 dMRI time point unit (much less than one time point). The accuracy of abnormal cycle detection reaches 80.0%. The proposed approach achieves results highly comparable to manual labeling in accuracy but with close to full automation of the whole process. The framework proposed here can be readily adapted to other modalities and dynamic imaging applications.

The potential of spring distraction to dynamically correct complex spinal deformities in the growing child

Purpose

Current treatment of progressive early onset scoliosis involves growth-friendly instrumentation if conservative treatment fails. These implants guide growth by passive sliding or repeated lengthenings. None of these techniques provide dynamic correction after implantation. We developed the spring distraction system (SDS), by using one or multiple compressed springs positioned around a standard sliding rod, to provide active continuous distraction of the spine to stimulate growth and further correction. The purpose of this study was to determine feasibility and proof of concept of the SDS.

Methods

We developed a versatile, dynamic spring distraction system for patients who would benefit from active continuous distraction. This prospective case series evaluates four patients with exceptional and progressive congenital spine deformities.

Results

Four patients had a mean age of 6.8 years at surgery with a mean follow-up of 36 months (range 25–45). The mean progressive thoracic lordosis, which was the reason for initiating surgical treatment in two patients, changed from 32° lordosis preoperatively to 1° kyphosis post-operatively. During follow-up, this further improved to 32° thoracic kyphosis. In the two other patients, with cervicothorcacic scoliosis, the main coronal curve improved from 79° pre-operatively to 56° post-operatively and further improved to 42°. The mean T1-S1 spine growth during follow-up for all patients was 1.3 cm/year. There was one reoperation because of skin problems and no device-failures.

Conclusion

These early results show the feasibility and the proof of concept of spring-based distraction as a dynamic growth-enhancing system with the potential of further correction of the deformity after implantation.

Thoracic Quantitative Dynamic MRI to Understand Developmental Changes in Normal Ventilatory Dynamics

BACKGROUND

A database of normative quantitative measures of regional thoracic ventilatory dynamics, which is essential to understanding better thoracic growth and function in children, does not exist.

RESEARCH QUESTION

How to quantify changes in the components of ventilatory pump dynamics during childhood via thoracic quantitative dynamic MRI (QdMRI)?

STUDY DESIGN AND METHODS

Volumetric parameters were derived via 51 dynamic MRI scans for left and right lungs, hemidiaphragms, and hemichest walls during tidal breathing. Volume-based symmetry and functional coefficients were defined to compare left and right sides and to compare contributions of the hemidiaphragms and hemichest walls with tidal volumes (TVs). Statistical analyses were performed to compare volume components among four age-based groups.

RESULTS

Right thoracic components were significantly larger than left thoracic components, with average ratios of 1.56 (95% CI, 1.41-1.70) for lung TV, 1.81 (95% CI, 1.60-2.03) for hemidiaphragm excursion TV, and 1.34 (95% CI, 1.21-1.47) for hemichest wall excursion TV. Right and left lung volumes at end-expiration showed, respectively, a 44% and 48% increase from group 2 (8 ≤ age < 10) to group 3 (10 ≤ age < 12). These numbers from group 3 to group 4 (12 ≤ age ≤ 14) were 24% and 28%, respectively. Right and left hemichest wall TVs exhibited, respectively, 48% and 45% increases from group 3 to group 4.

INTERPRETATION

Normal right and left ventilatory volume components have considerable asymmetry in morphologic features and dynamics and change with age. Chest wall and diaphragm contributions vary in a likewise manner. Thoracic QdMRI can provide quantitative data to characterize the regional function and growth of the thorax as it relates to ventilation.

Magnetic Controlled Growth Rods in the Treatment of Scoliosis: Safety, Efficacy and Patient Selection

Early-onset scoliosis is defined as a spinal curvature greater than 10° in children prior to 10 years of age. Untreated EOS may lead to progressively severe spinal deformity, impaired pulmonary development, restrictive lung disease, and both increased morbidity and mortality. Limitations of established conservative treatments include inability to correct severe deformity, as well as challenges with compliance when casting and bracing is applied. In addition, surgical treatment in the form of traditional growing rods requires regular surgical lengthenings and is associated with complications inherent with repeated invasive procedures and exposure to general anesthesia. MAGEC is an evolving magnetically controlled growing rod system for the treatment of EOS. After initial implantation, lengthening is achieved non-invasively by using magnetic external remote control. MAGEC offers the potential to control moderate and severe EOS, while avoiding repeated surgical procedures and associated complications. In this review, we examine the results from clinical, radiological and explant studies following the use of MAGEC, in the context of other established and emerging treatments for EOS.

Infection in neuro-muscular scoliosis deformity correction

Assess the outcome of a standardised protocol for the treatment of post-operative wound infection in patients undergoing deformity correction for neuro-muscular scoliosis (NMS). Retrospective review of 443 consecutive patients with a minimum 18 months' follow-up, following a primary posterior deformity correction for NMS. In patients who developed a wound complication, the patient demographic and comorbidities, causative pathogen, number of re-operations, length of stay (LOS), rate of cure, and complications were analysed. Forty-four patients (9.9%) developed a wound infection. Marginally more infections were mono-microbial (23) than poly-microbial (21). Coagulase negative staphylococcus and Staphylococcus aureus were the most commonly cultured pathogens. Seventeen patients were treated with antibiotics alone, while 27 patients also required surgical debridement. The average LOS for those treated with antibiotics alone was 12 days (range: 9-15 days), in contrast to those requiring debridement, which was 35 days (range: 35-70 days). All patients were cured from their infection and ultimately achieved fusion. Infection is common in NMS deformity correction. This is marginally more common as a mono-microbial than poly-microbial infection with most pathogens being staphylococcal in origin. Our defined treatment strategy resulted in a cure for all patients and capacity for all patients to achieve fusion.

Long term outcome of vertical expandable prosthetic titanium rib treatment in children with early onset scoliosis

The vertical expandable prosthetic titanium rib (VEPTR) device was originally developed for the treatment of thoracic insufficiency syndrome with the aim of improving respiratory function of affected patients. Although clinically obvious, the changes in pulmonary function of VEPTR-treated patients are difficult to assess when using common lung function tests, and newer techniques based on functional magnetic resonance imaging (MRI) are currently being evaluated. The potential of improving lung function and simultaneously controlling the spinal deformity has continuously broadened the spectrum of indications for VEPTR, not least due to the frequent reports of complications with spine-based traditional growing rods (tGR). However, the initial enthusiasm of spine-sparing deformity correction has progressively subsided with the increasing number of reports on complications, including the detection of extraspinal ossifications along the implants and across ribs. The avoidance of repetitive surgical implant lengthening with the availability of motorized distraction-based implants has further diminished the use of VEPTR, especially in the absence of volume-depletion deformities of the thorax. In view of the still scarce reporting on the ultimate strategy of VEPTR treatment and the lack of long-term follow-up of patients receiving growth-sparing surgery, only limited conclusions can be drawn so far. Based on the available reports, however, the intended deformity corrections with final fusion surgeries can be achieved to a rather limited extent, while the complication and reoperation rates are still very high.

Quantitative Dynamic Thoracic MRI: Application to Thoracic Insufficiency Syndrome in Pediatric Patients

Background Available methods to quantify regional dynamic thoracic function in thoracic insufficiency syndrome (TIS) are limited. Purpose To evaluate the use of quantitative dynamic MRI to depict changes in regional dynamic thoracic function before and after surgical correction of TIS. Materials and Methods Images from free-breathing dynamic MRI in pediatric patients with TIS (July 2009-August 2015) were retrospectively evaluated before and after surgical correction by using vertical expandable prosthetic titanium rib (VEPTR). Eleven volumetric parameters were derived from lung, chest wall, and diaphragm segmentations, and parameter changes before versus after operation were correlated with changes in clinical parameters. Paired analysis from Student t test on MRI parameters and clinical parameters was performed to detect if changes (from preoperative to postoperative condition) were statistically significant. Results Left and right lung volumes at end inspiration and end expiration increased substantially after operation in pediatric patients with thoracic insufficiency syndrome, especially right lung volume with 22.9% and 26.3% volume increase at end expiration (P = .001) and end inspiration (P = .002), respectively. The average lung tidal volumes increased after operation for TIS; there was a 43.8% and 55.3% increase for left lung tidal volume and right lung tidal volume (P < .001 for both), respectively. However, clinical parameters did not show significant changes from pre- to posttreatment states. Thoracic and lumbar Cobb angle were poor predictors of MRI tidal volumes (chest wall, diaphragm, and left and right separately), but assisted ventilation rating and forced vital capacity showed moderate correlations with tidal volumes (chest wall, diaphragm, and left and right separately). Conclusion Vertical expandable prosthetic titanium rib operation was associated with postoperative increases in all components of tidal volume (left and right chest wall and diaphragm, and left and right lung tidal volumes) measured at MRI. Clinical parameters did not demonstrate improvements in postoperative tidal volumes. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Paltiel in this issue.

[Surgical "no-touch" distraction technique to correct pediatric scoliosis]

OBJECTIVE

Reduction and retention of the scoliotic curve in children with progressive spinal deformities.

INDICATIONS

Progressive neuromyopathic scoliosis which cannot be controlled conservatively (especially by walking disability), and/or development of a thorax insufficiency syndrome (TIS).

CONTRAINDICATIONS

Insufficient soft tissue coverage; body weight < 11.4 kg; body mass index (BMI) > 25 or >50 kg; missing osseous anchoring structures (ribs); adult skeleton (usually age < 12 years at surgery); severe spasticity.

SURGICAL TECHNIQUE

Indirect correction and distraction of the spinal deformity by two extendable, paravertebral telescopic implants, anchored to the cranial ribs and the iliac crest; the spine is not compromised surgically.

POSTOPERATIVE MANAGEMENT

Early functional therapy, no brace; multiple surgical (VEPTR®-system) or externally (magnetically controlled rods) controlled extensions per year.

RESULTS

The surgical paravertebral "no-touch" technique for spine correction is particularly suitable for children with neuromyopathic scoliosis with a body weight > 11.4 kg. Our prospective group of children (n = 45), was treated with a combination of the classic vertical expandable prosthetic titanium rib (VEPTR®) anchored to the ribs and iliac crest combined with a magnetically controlled telescopic implant (MAGEC®). The primary correction of >50% was achieved, while progression was effectively prevented over years. In 495 outpatient lengthening procedures, the rate of implant-associated complications requiring surgery was 3.7%. Of the 45 children, 13 (29%) underwent surgical revision. With the proposed surgical "no-touch" technique for scoliosis correction of pediatric neuromyopathic deformities, an effective reduction of the scoliotic curve can be achieved and maintained. Advantages of the method are a partial retention of spinal flexibility and a reduction of spinal ossifications, which facilitates dorsal spondylodesis as the final treatment.

Treatment of early-onset scoliosis with growing rods in patients with neurofibromatosis-1

This study aimed at verifying the efficacy of growing rod treatment in patients affected by neurofibromatosis with early-onset scoliosis. The authors present a retrospective case study of seven children treated between 2001 and 2017. Mean age at initial surgery was 7.2 years. Mean Cobb angle was 82.7°. Lengthening was performed once a year. Mean Cobb angle at last follow-up was 50.1°. Mean spinal growth was 13.6 mm/year, with regular gain during lengthening procedures. Mean follow-up period was 7 years after the first surgery. Three patients underwent final fusion. Complications were one proximal junctional kyphosis, nine rod breakages, and one hook dislocation.

Two-stage posterior spinal fusion for early-onset scoliosis: Two case reports

RATIONALE

Fusionless techniques for early-onset scoliosis (EOS) have evolved to allow near-normal growth while maintaining the correction achieved during the initial surgery. However, such procedures require repeated surgeries and have increased complication rates. We have developed a 2-stage fusion technique using pedicle screws for EOS to reduce patient burden and complication risk. This series describes the clinical and radiological features of 2 patients with EOS who received 2-stage posterior spinal fusion. This surgical method for EOS represents the first of its kind.

PATIENT CONCERNS

Case 1 was a 10-year-old girl who was diagnosed as having scoliosis with Prader Willi syndrome at the age of 2 years. Her preoperative major curve Cobb angle was 100 degrees at age 10 years. Case 2 was an 11-year-old boy who was found to have scoliosis with 22q11.2 deletion syndrome at the age of 4 years. His preoperative major curve Cobb angle was 77 degrees at age 11 years.

DIAGNOSIS

Whole-spine radiographs were performed to diagnose scoliosis.

INTERVENTIONS

Both patients received 2-stage posterior spinal fusion.

OUTCOMES

Postoperative Cobb angle of the major curve improved to 46 and 48 degrees, respectively. Thoracic height respectively improved from 160 and 148 mm before surgery to 206 and 211 mm at final follow-up. Surgical outcome as evaluated by Scoliosis Research Society-22 patient questionnaires revealed acceptable results without any severe complications.

LESSONS

Based on the present case report, 2-stage posterior spinal fusion for EOS achieves good radiological and clinical outcomes without severe complications.

EVALUATION OF THE VEPTR SYSTEM IN THE MANAGEMENT OF SPINAL DEFORMITIES BETWEEN 2008 AND 2014 AT THE ROOSEVELT INSTITUTE

ABSTRACT Objective: Traditional surgical treatments, such as on-site fusion and hemiepiphysiodesis, have not addressed chest deformity in its three dimensions, and are usually insufficient and unpredictable for the management of congenital and neuromuscular scoliosis. The application of the Vertical Expandable Prosthetic Titanium Rib (VEPTR) is a technique developed to treat early-onset progressive scoliosis that elongates the spine and thoracic wall, allowing adequate lung development. Methods: A case series retrospective study was conducted. We included 23 patients, including fifteen females and eight males diagnosed with congenital and neuromuscular scoliosis, who were treated with VEPTR type implants between January 2008 and May 2014. We obtained data about the implant and pre and postoperative radiographic images to assess the magnitude of the curve, and we measured the Cobb angle and length after lengthening, as well as evaluating the complications found. Results: There was an improvement in the postoperative Cobb angle. In patients with congenital scoliosis, deformity correction was 8.6% (p=0.014), and in neuromuscular scoliosis, we observed deformity correction of 19.5% (p=0.009). Likewise, we found gains in thoracic height through the device, which results in an average 10% lengthening of the spine in congenital scoliosis. In this study, we identified complications such as material migrations, rib synostosis, pressure zones, rib fracture, hemothorax, and deep wound infection. Conclusion: The natural history of progressive spinal deformity was improved in most of the minors, through the use of VEPTR. This allows us to continue managing patients in the future, in order to make a deeper assessment of its performance in treatment of early onset scoliosis. Level of Evidence III; Therapeutic studies - Investigating the results of a treatment.

Spiro A, Kunkel P, Grolle B, Stücker R, Rupprecht M. Strategies for Treating Scoliosis in Early Childhood

BACKGROUND

Scoliosis in early childhood is defined as abnormal curvature of the spine of any etiology that arises before age 10. The affected children are at high risk of developing restrictive pulmonary dysfunction. The treatment presents major challenges because of the complexity and high morbidity of the disease.

METHODS

This article is based on pertinent articles retrieved by a selective literature search, and on the results of a retrospective study by the authors.

RESULTS

In addition to conservative treatment methods including physiotherapy, casts, and corsets, progressive scoliosis usually requires early surgical intervention. In recent years, many different so-called non-fusion techniques have been developed for the surgical treatment of early childhood scoliosis. The goal of this new strategy is to avoid early fusion procedures and to enable further growth of the rib cage, lungs, and spine in addition to correcting the scoliosis. The authors also present their own intermediate-term results with a novel growth-preserving spinal operation that exploits magnet technology.

CONCLUSION

Because of the low prevalence and heterogeneous etiology of early childhood scoliosis, the literature to date contains no randomized controlled therapeutic trials concerning this small group of high-risk patients. For the treatment to succeed, it is essential for specialists from all of the involved medical disciplines to work closely together. Conservative measures such as physiotherapy, casts, and corsets can delay the (frequent) need for surgery or even make surgery unneces - sary, particularly in the idiopathic types of early childhood scoliosis. The new non-fusion techniques enable continued growth of the spine, rib cage, and lung in addition to correcting the scoliosis.

Quantitative dynamic MRI (QdMRI) Volumetric Analysis of Pediatric Patients with Thoracic Insufficiency Syndrome

The lack of standardizable objective diagnostic measurement techniques is a major hurdle in the assessment and treatment of pediatric patients with thoracic insufficiency syndrome (TIS). The aim of this paper is to explore quantitative dynamic MRI (QdMRI) volumetric parameters derived from thoracic dMRI in pediatric patients with TIS and the relationships between dMRI parameters and clinical measurements. 25 TIS patients treated with vertical expandable prosthetic titanium rib (VEPTR) surgery are included in this retrospective study. Left and right lungs at end-inspiration and end-expiration are segmented from constructed 4D dMRI images. Lung volumes and excursion (or tidal) volumes of the left/right chest wall and hemi-diaphragms are computed. Commonly used clinical parameters include thoracic and lumbar Cobb angles and respiratory measurements from pulmonary function testing (PFT). 200 3D lungs in total (left & right, pre-operative & post-operative, end-inspiration & end-expiration) are segmented for analysis. Our analysis indicates that change of resting breathing rate (RR) following surgery is negatively correlated with that of QdMRI parameters. Chest wall tidal volumes and hemi-diaphragm tidal volumes increase significantly following surgery. Clinical parameter RR reduced after surgical treatment with P values around 0.06 but no significant differences were found on other clinical parameters. The significant increase in post-operative tidal volumes suggests a treatment-related improvement in lung capacity. The reduction of RR following surgery shows that breathing function is improved. The QdMRI parameters may offer an objective marker set for studying TIS, which is currently lacking.

Lung Parenchymal Analysis on Dynamic MRI in Thoracic Insufficiency Syndrome to Assess Changes Following Surgical Intervention

General surgeons, orthopedists, and pulmonologists individually treat patients with thoracic insufficiency syndrome (TIS). The benefits of growth-sparing procedures such as Vertical Expandable Prosthetic Titanium Rib (VEPTR)insertionfor treating patients with TIS have been demonstrated. However, at present there is no objective assessment metricto examine different thoracic structural components individually as to their roles in the syndrome, in contributing to dynamics and function, and in influencing treatment outcome. Using thoracic dynamic MRI (dMRI), we have been developing a methodology to overcome this problem. In this paper, we extend this methodology from our previous structural analysis approaches to examining lung tissue properties. We process the T2-weighted dMRI images through a series of steps involving 4D image construction of the acquired dMRI images, intensity non-uniformity correction and standardization of the 4D image, lung segmentation, and estimation of the parameters describing lung tissue intensity distributions in the 4D image. Based on pre- and post-operative dMRI data sets from 25 TIS patients (predominantly neuromuscular and congenital conditions), we demonstrate how lung tissue can be characterized by the estimated distribution parameters. Our results show that standardized T2-weighted image intensity values decrease from the pre- to post-operative condition, likely reflecting improved lung aeration post-operatively. In both pre- and post-operative conditions, the intensity values decrease also from end-expiration to end-inspiration, supporting the basic premise of our results.

Use of a Vertical Expandable Prosthetic Titanium Rib in Children With Thoracic Insufficiency Syndrome and Scoliosis

Thoracic insufficiency syndrome is the inability of the thorax to support normal respiration or lung growth. One treatment to address the thoracic deformities associated with the syndrome is placement of a vertical expandable prosthetic titanium rib. The goal is to restore thoracic volume, symmetry, and function and to allow for growth of the thorax in skeletally immature children. The main topics include indications for placement of a titanium rib, postoperative nursing care, potential complications, long-term follow-up, quality-of-life issues, and implications for critical care nurses and advanced practice nurses.

Magnetically Controlled Devices Parallel to the Spine in Children with Spinal Muscular Atrophy

Background:

Children with severe spinal deformity frequently are managed with growth-friendly implants. After initial surgery, externally controlled magnetic rods allow spinal deformity correction during growth without further surgical intervention. The ability to lengthen the spine without additional surgical procedures is especially beneficial in high-risk children, such as those with spinal muscular atrophy (SMA). The purpose of the present study was to assess the level of control of spinal deformity in a homogeneous group of patients with SMA who were managed with magnetically controlled implants for 2 years.

Methods:

This prospective, nonrandomized study included 21 non-ambulatory children with type-II SMA and progressive scoliosis who were managed bilaterally with a magnetically controlled implant that was inserted parallel to the spine with use of rib-to-pelvis hook fixation. Radiographic measurements of scoliotic curves, kyphosis, lordosis, pelvic obliquity, and spinal length were performed before and after implantation of the magnetically controlled device and during external lengthening. The mean duration of follow-up was 2 years.

Results:

The mean main curve of patients without prior vertical expandable prosthetic titanium rib (VEPTR) treatment decreased from 70° before implantation of the magnetically controlled device to 30° after implantation of the device. Correction was maintained during the follow-up period, with a mean curve of 31° at the time of the latest follow-up at 2.2 years. Pelvic obliquity was surgically corrected by 76% (from 17° to 4°) and remained stable during follow-up. Thoracic kyphosis could not be corrected within the follow-up period. Spinal length of children without prior spinal surgery increased by >50 mm immediately after device implantation and steadily increased at a rate of 13.5 mm/yr over the course of treatment. During treatment, 4 general complications occurred and 6 lengthening procedures failed, with 3 patients requiring surgical revision.

Conclusions:

Bilateral implantation of an externally controlled magnetic rod with rib-to-pelvis fixation represents a safe and efficient method to control spinal deformity in children with SMA, achieving sufficient and stable curve correction as well as increased spinal length. The complication rate was lower than those that have been described for VEPTR and other growing rod instrumentation strategies.

Level of Evidence:

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

The Classification for Early-onset Scoliosis (C-EOS) Correlates With the Speed of Vertical Expandable Prosthetic Titanium Rib (VEPTR) Proximal Anchor Failure

BACKGROUND

The Classification for Early-onset Scoliosis (C-EOS) was developed by a consortium of early-onset scoliosis (EOS) surgeons. This study aims to examine if the C-EOS classification correlates with the speed (failure/unit time) of proximal anchor failure in EOS surgery patients.

METHODS

A total of 106 EOS patients were retrospectively queried from an EOS database. All patients were treated with vertical expandable prosthetic titanium rib and experienced proximal anchor failure. Patients were classified by the C-EOS, which includes a term for etiology [C: Congenital (54.2%), M: Neuromuscular (32.3%), S: Syndromic (8.3%), I: Idiopathic (5.2%)], major curve angle [1: ≤20 degrees (0%), 2: 21 to 50 degrees (15.6%), 3: 51 to 90 degrees (66.7%), 4: >90 degrees (17.7%)], and kyphosis ["-": ≤20 (13.5%), "N": 21 to 50 (42.7%), "+": >50 (43.8%)]. Outcome was measured by time and number of lengthenings to failure.

RESULTS

Analyzing C-EOS classes with >3 subjects, survival analysis demonstrates that the C-EOS discriminates low, medium, and high speed of failure. The low speed of failure group consisted of congenital/51-90/hypokyphosis (C3-) class. The medium-speed group consisted of congenital/51-90/normal and hyperkyphosis (C3N, C3+), and neuromuscular/51-90/hyperkyphosis (M3+) classes. The high-speed group consisted of neuromuscular/51-90/normal kyphosis (M3N), and neuromuscular/>90/normal and hyperkyphosis (M4N, M4+) classes. Significant differences were found in time (P<0.05) and number of expansions (P<0.05) before failure between congenital and neuromuscular classes.As isolated variables, neuromuscular etiology experienced a significantly faster time to failure compared with patients with idiopathic (P<0.001) and congenital (P=0.026) etiology. Patients with a major curve angle >90 degrees demonstrated significantly faster speed of failure compared with patients with major curve angle 21 to 50 degrees (P=0.011).

CONCLUSIONS

The ability of the C-EOS to discriminate the speeds of failure of the various classification subgroups supports its validity and demonstrates its potential use in guiding decision making. Further experience with the C-EOS may allow more tailored treatment, and perhaps better outcomes of patients with EOS.

LEVEL OF EVIDENCE

Level III.

Interactive iterative relative fuzzy connectedness lung segmentation on thoracic 4D dynamic MR images

Lung delineation via dynamic 4D thoracic magnetic resonance imaging (MRI) is necessary for quantitative image analysis for studying pediatric respiratory diseases such as thoracic insufficiency syndrome (TIS). This task is very challenging because of the often-extreme malformations of the thorax in TIS, lack of signal from bone and connective tissues resulting in inadequate image quality, abnormal thoracic dynamics, and the inability of the patients to cooperate with the protocol needed to get good quality images. We propose an interactive fuzzy connectedness approach as a potential practical solution to this difficult problem. Manual segmentation is too labor intensive especially due to the 4D nature of the data and can lead to low repeatability of the segmentation results. Registration-based approaches are somewhat inefficient and may produce inaccurate results due to accumulated registration errors and inadequate boundary information. The proposed approach works in a manner resembling the Iterative Livewire tool but uses iterative relative fuzzy connectedness (IRFC) as the delineation engine. Seeds needed by IRFC are set manually and are propagated from slice-to-slice, decreasing the needed human labor, and then a fuzzy connectedness map is automatically calculated almost instantaneously. If the segmentation is acceptable, the user selects "next" slice. Otherwise, the seeds are refined and the process continues. Although human interaction is needed, an advantage of the method is the high level of efficient user-control on the process and non-necessity to refine the results. Dynamic MRI sequences from 5 pediatric TIS patients involving 39 3D spatial volumes are used to evaluate the proposed approach. The method is compared to two other IRFC strategies with a higher level of automation. The proposed method yields an overall true positive and false positive volume fraction of 0.91 and 0.03, respectively, and Hausdorff boundary distance of 2 mm.

Retrospective 4D MR image construction from free-breathing slice Acquisitions: A novel graph-based approach

PURPOSE

Dynamic or 4D imaging of the thorax has many applications. Both prospective and retrospective respiratory gating and tracking techniques have been developed for 4D imaging via CT and MRI. For pediatric imaging, due to radiation concerns, MRI becomes the de facto modality of choice. In thoracic insufficiency syndrome (TIS), patients often suffer from extreme malformations of the chest wall, diaphragm, and/or spine with inability of the thorax to support normal respiration or lung growth (Campbell et al., 2003, Campbell and Smith, 2007), as such patient cooperation needed by some of the gating and tracking techniques are difficult to realize without causing patient discomfort and interference with the breathing mechanism itself. Therefore (ventilator-supported) free-breathing MRI acquisition is currently the best choice for imaging these patients. This, however, raises a question of how to create a consistent 4D image from such acquisitions. This paper presents a novel graph-based technique for compiling the best 4D image volume representing the thorax over one respiratory cycle from slice images acquired during unencumbered natural tidal-breathing of pediatric TIS patients.

METHODS

In our approach, for each coronal (or sagittal) slice position, images are acquired at a rate of about 200-300ms/slice over several natural breathing cycles which yields over 2000 slices. A weighted graph is formed where each acquired slice constitutes a node and the weight of the arc between two nodes defines the degree of contiguity in space and time of the two slices. For each respiratory phase, an optimal 3D spatial image is constructed by finding the best path in the graph in the spatial direction. The set of all such 3D images for a given respiratory cycle constitutes a 4D image. Subsequently, the best 4D image among all such constructed images is found over all imaged respiratory cycles. Two types of evaluation studies are carried out to understand the behavior of this algorithm and in comparison to a method called Random Stacking - a 4D phantom study and 10 4D MRI acquisitions from TIS patients and normal subjects. The 4D phantom was constructed by 3D printing the pleural spaces of an adult thorax, which were segmented in a breath-held MRI acquisition.

RESULTS

Qualitative visual inspection via cine display of the slices in space and time and in 3D rendered form showed smooth variation for all data sets constructed by the proposed method. Quantitative evaluation was carried out to measure spatial and temporal contiguity of the slices via segmented pleural spaces. The optimal method showed smooth variation of the pleural space as compared to Random Stacking whose behavior was erratic. The volumes of the pleural spaces at the respiratory phase corresponding to end inspiration and end expiration were compared to volumes obtained from breath-hold acquisitions at roughly the same phase. The mean difference was found to be roughly 3%.

CONCLUSIONS

The proposed method is purely image-based and post-hoc and does not need breath holding or external surrogates or instruments to record respiratory motion or tidal volume. This is important and practically warranted for pediatric patients. The constructed 4D images portray spatial and temporal smoothness that should be expected in a consistent 4D volume. We believe that the method can be routinely used for thoracic 4D imaging.

Incidence of proximal junctional kyphosis with magnetic expansion control rods in early onset scoliosis

BACKGROUND

The introduction of magnetic expansion control growth rods for the surgical management of EOS has gained popularity. However, there are no published studies on the incidence of proximal junctional kyphosis (PJK) using this technique.

PURPOSE

The aim of this study is to report the incidence of PJK following treatment with magnetic growth rods in EOS.

METHODS

Retrospective review of data from 21 cases (12 males, 9 females) over 3 years. PJK was obtained from whole spine X-rays pre-op, immediate post-op and last follow-up. Cobb angle was measured between the superior end plate of vertebra two levels above the upper instrumented vertebra (UIV) and the inferior end plate of the UIV. A difference of >10° between the pre-operative x-rays and the last follow-up X-rays was recorded as PJK.

RESULTS

6/21 (28.6 %) had proximal junctional kyphosis of more than 10° at last follow-up. Average age was 5.3. Average follow-up was 32.5 months. All the patients with PJK were syndromic. Four out of these six patients were males (66 %). Average PJK angle was 25.55°. Average pre-operative kyphosis was 52.5°. Average number of distractions was 7.4. All six patients had syndromic association. 3/6 patients (50 %) were conversion cases treated with traditional growth rods previously (TGR). None of the patients required unplanned surgery for PJK.

CONCLUSION

The incidence of PJK in EOS patients treated with magnetic rods is favourably comparable to that reported with traditional growth rods. Also, children who are male, syndromic, hyperkyphotic, and younger must be monitored closely.

Bilateral Rib-Based Distraction to the Pelvis for the Management of Congenital Gibbus Deformity in the Growing Child With Myelodysplasia

BACKGROUND

Congenital gibbus deformity of the spine associated with myelodysplasia is a challenging problem in the growing child and is commonly associated with skin breakdown and chronic infection. Surgical solutions including kyphectomy, flap closure of the skin, and early spinal fusion are associated with a high rate of complications and, ultimately, a short trunk due to stoppage of spinal growth. The purpose of this article is to describe our early results in using a rib-based distraction to the pelvis without vertebral resection and fusion to manage this deformity.

METHODS

This is an IRB-approved retrospective study of a consecutive single-surgeon series of using the rib-to-pelvis distraction technique in congenital gibbus deformity. There were four patients (two males, two females) with an average age of 20 months (16-25 months). The diagnosis was myelomeningocele (n = 2), congenital kyphosis (n = 1), and congenital kyphoscoliosis (n = 1). All patients were managed with bilateral rib-to-pelvis distraction using the Vertical Expandable Prosthetic Titanium Rib (VEPTR) device.

RESULTS

The average preoperative gibbus deformity measured 114 degrees (range = 108-154). The average postoperative gibbus measured 52 degrees (range = 36-80). The average length of postoperative follow-up is 66 months (range = 48-84 months). There were 10 complications; a dural leak during device expansion, rib hook migrations and postoperative infections after initial implant that resolved with irrigation, debridement, and intravenous antibiotics. One patient had skin expanders placed preoperatively to facilitate skin coverage. No patient has required vertebral resection to achieve correction of the deformity. No patient has had subsequent skin breakdown over the residual gibbus.

DISCUSSION

This minimally invasive technique effectively corrects gibbus deformity in the growing child without early vertebral column resection and fusion. Our practice is to intervene early while the gibbus is flexible and prior to skin breakdown over the deformity. These early results are encouraging, but further long-term follow-up is needed to confirm the benefits of this technique over traditional methods.

LEVEL OF EVIDENCE

IV.

Fusionless surgery in early-onset scoliosis

BACKGROUND

Surgical treatment of early-onset scoliosis has greatly developed in recent years. Early-onset scoliosis covers a variety of etiologies (idiopathic, neurologic, dystrophic, malformative, etc.) with onset before the age of 5 years. Progression and severity threaten respiratory development and may result in respiratory failure in adulthood. Many surgical techniques have been developed in recent years, aiming to protect spinal and thoracic development.

MATERIAL AND METHODS

Present techniques are based on one of two main principles. The first consists in posterior distraction of the spine in its concavity (single growing rod, or vertical expandable prosthetic titanium rib [VEPTR]), or on either side (dual rod); this requires iterative surgery, for lengthening, unless motorized using energy provided by a magnetic system. The second option is to use spinal growth force to lengthen the assembly; these techniques (Luque Trolley, Shilla), using a sliding assembly, are known as growth guidance.

RESULTS

These techniques are effective in controlling early scoliotic deformity, and to some extent restore spinal growth. However, they show a high rate of complications: infection, rod breakage, spinal fixation pull out and, above all, progressive spinal stiffness, reducing long-term efficacy. Respiratory gain is harder to assess, as thoracic expansion does not systematically improve respiratory function, particularly due to impaired compliance of the thoracic cage.

[Adolescent scoliosis : From deformity to treatment]

Scoliosis affects up to 6 % of the population. The resulting spine deformity, the increasing risk of back pain, cosmetic aspects, pulmonary disorders if the Cobb angle is > 80°, and the progress of the deformity to > 50° after the end of growth indicate non-operative or operative therapy. In daily clinical practice, the classifications of scoliosis allow the therapy to be adapted. Classifications consider deformity, topography of the scoliosis, and the age at diagnosis. This publication gives an overview of the relevant and most common classifications in the treatment of adolescent scoliosis. For evaluation, the deformity measurement on the coronary radiographic projection of the total spine (Cobb angle) is relevant to therapy. The classification of topography, form, and the sagittal profile of the deformity of the spine are useful for preoperative planning of the fusion level. Classifications that take into account the age at the time of the diagnosis of scoliosis differentiate among early onset scoliosis (younger than 10 years of age), adolescent scoliosis (up to the end of growth), and adult scoliosis. Early onset scoliosis is subdivided by age and etiology. Therapy is derived from the classification of clinical and radiological findings. Classifications that take into account clinical and radiological parameters are essential components of modern scoliosis therapy.

[Treatment of early onset scoliosis : How far can we go?]

BACKGROUND

Recently, inconsistent definitions of early onset scoliosis (EOS) and a wide variety of treatment options have been observed.

OBJECTIVES

To clearly define the term EOS, to depict non-operative and operative treatment options, and to present the limitations of the boundaries of these techniques.

METHODS

Review of the literature, including conference presentations and expert opinions, in addition to personal experiences.

RESULTS

Early onset scoliosis (EOS) refers to spine deformity that is present before 10 years of age, regardless of etiology. All existing operative treatment options share a high risk of complications. Therefore, non-operative treatment should act as a time-buying approach to postpone surgery.

DISCUSSION

Awareness of treatment options and their specific indications, in addition to respecting each patient's individual needs and feasibilities, are crucial for the optimal outcome.

Extent of Spine Deformity Predicts Lung Growth and Function in Rabbit Model of Early Onset Scoliosis

Early onset deformity of the spine and chest wall (initiated <8 years of age) is associated with increased morbidity at adulthood relative to adolescent onset deformity of comparable severity. Presumably, inhibition of thoracic growth during late stage alveolarization leads to an irreversible loss of pulmonary growth and thoracic function; however the natural history of this disease from onset to adulthood has not been well characterized. In this study we establish a rabbit model of early onset scoliosis to establish the extent that thoracic deformity affects structural and functional respiratory development. Using a surgical right unilateral rib-tethering procedure, rib fusion with early onset scoliosis was induced in 10 young New Zealand white rabbits (3 weeks old). Progression of spine deformity, functional residual capacity, total lung capacity, and lung mass was tracked through longitudinal breath-hold computed tomography imaging up to skeletal maturity (28 weeks old). Additionally at maturity forced vital capacity and regional specific volume were calculated as functional measurements and histo-morphometry performed with the radial alveolar count as a measure of acinar complexity. Data from tethered rib rabbits were compared to age matched healthy control rabbits (N = 8). Results show unilateral rib-tethering created a progressive spinal deformity ranging from 30° to 120° curvature, the severity of which was strongly associated with pulmonary growth and functional outcomes. At maturity rabbits with deformity greater than the median (55°) had decreased body weight (89%), right (59%) and left (86%) lung mass, right (74%) and left (69%) radial alveolar count, right lung volume at total lung capacity (60%), and forced vital capacity (75%). Early treatment of spinal deformity in children may prevent pulmonary complications in adulthood and these results provide a basis for the prediction of pulmonary development from thoracic structure. This model may also have future use as a platform to evaluate treatment effectiveness.

Expansion Thoracoplasty for Thoracic Insufficiency Syndrome Associated with Jarcho-Levin Syndrome

Introduction

Although surgical treatment of spondylothoracic dysplasia (STD) is controversial, we have found that an expansion thoracoplasty using a Vertical Expandable Prosthetic Titanium Rib (VEPTR; DePuy Synthes) results in favorable outcomes, including 100% survivability (at an average follow-up of 6.2 years), increased thoracic spinal length, and decreased requirements for ventilation support.

Step 1 Preoperative Preparation

Make anteroposterior and lateral radiographs of the spine.

Step 2 Position the Patient for the Procedure

The patient is placed in the prone position.

Step 3 The Incision

A curvilinear skin incision is made, starting proximally between the spine and the medial edge of the scapula.

Step 4 The Osteotomy

Perform the v-osteotomy.

Step 5 Placement of the VEPTR Device

A number-4 VEPTR-I device is wedged in, starting laterally within the osteotomy sites, wedging the osteotomies apart, distracting the superior ribs proximally and the inferior ribs distally, lengthening the hemithorax, and stopping approximately at the posterior axillary line, when there is maximum stress on the superior and inferior ribs, to avoid fracture, and the lamina spreaders are then removed.

Step 6 Wound Closure

Insert drains and local anesthetic catheters and close the wound.

Step 7 Expansion and Replacement Procedures

Lengthen the devices with the standard VEPTR technique of limited 3-cm incisions every three to six months.

Results

VEPTR treatment in patients with STD is associated with increased thoracic spine height and reduced thoracic width-to-height ratio, suggesting a greater gain in height than in width.

What to Watch For

IndicationsContraindicationsPitfalls & Challenges.

Vertical expandable prosthetic titanium rib (VEPTR): a review of indications, normal radiographic appearance and complications

Vertical expandable prosthetic titanium rib (VEPTR) is increasingly used in the treatment of thoracic insufficiency, idiopathic and neuromuscular scoliosis and chest wall defects in children. In contrast to spinal fusion surgery, the VEPTR allows for growth while stabilizing the deformity. We illustrate the common indications and normal radiographic appearance of the three common configurations of VEPTR (cradle-to-cradle assembly, cradle with lumbar extension assembly, cradle-to-ala hook assembly). There is a relatively high rate of reported complications with VEPTR in the literature. We discuss the potential complications of VEPTR, including infection, rib fracture, dislodged hardware and neurological injury, with an emphasis on imaging diagnosis.

Operative management of traumatic cervical spine distraction and complete cord transection in a 3-year-old patient

This report describes the presentation and operative treatment of a 3-year-old boy who survived a motor vehicle accident that resulted in a C6-7 distraction injury, complete avulsion of the spinal cord, and gross spinal instability. Only 5%-10% of all spinal cord and vertebral column injuries occur in children. Survival after such an injury is exceptionally rare in very young patients and is associated with severe neurological deficits. The authors discuss the substantial ethical challenges involved in the care of a patient with this injury. To their knowledge, only two other cases of survival have been reported in pediatric patients following motor vehicle trauma resulting in complete injury to the lower cervical spinal cord.

Early-onset scoliosis: current treatment

Early-onset scoliosis, which appears before the age of 10, can be due to congenital vertebral anomalies, neuromuscular diseases, scoliosis-associated syndromes, or idiopathic causes. It can have serious consequences for lung development and significantly reduce the life expectancy compared to adolescent scoliosis. Extended posterior fusion must be avoided to prevent the crankshaft phenomenon, uneven growth of the trunk and especially restrictive lung disease. Conservative (non-surgical) treatment is used first. If this fails, fusionless surgery can be performed to delay the final fusion procedure until the patient is older. The gold standard delaying surgical treatment is the implantation of growing rods as described by Moe and colleagues in the mid-1980s. These rods, which are lengthened during short surgical procedures at regular intervals, curb the scoliosis progression until the patient reaches an age where fusion can be performed. Knowledge of this technique and its complications has led to several mechanical improvements being made, namely use of rods that can be distracted magnetically on an outpatient basis, without the need for anesthesia. Devices based on the same principle have been designed that preferentially attach to the ribs to specifically address chest wall and spine dysplasia. The second category of surgical devices consists of rods used to guide spinal growth that do not require repeated surgical procedures. The third type of fusionless surgical treatment involves slowing the growth of the scoliosis convexity to help reduce the Cobb angle. The indications are constantly changing. Improvements in surgical techniques and greater surgeon experience may help to reduce the number of complications and make this lengthy treatment acceptable to patients and their family. Long-term effects of surgery on the Cobb angle have not been compared to those involving conservative "delaying" treatments. Because the latter has fewer complications associated with it than surgery, it should be the first-line treatment for most cases of early-onset scoliosis.

Chest wall hypoplasia--principles and treatment

The chest is a dynamic structure. For normal movement it relies on a coordinated movement of the multiple bones, joints and muscles of the respiratory system. While muscle weakness can have clear impact on respiration by decreasing respiratory motion, so can conditions that cause chest wall hypoplasia and produce an immobile chest wall. These conditions, such as Jarcho-Levin and Jeune syndrome, present significantly different challenges than those faced with early onset scoliosis in which chest wall mechanics and thoracic volume may be much closer to normal. Because of this difference more aggressive approaches to clinical and surgical management are necessary.

Apical and intermediate anchors without fusion improve Cobb angle and thoracic kyphosis in early-onset scoliosis

BACKGROUND

The main goal of treatment in early-onset scoliosis is to obtain and maintain curve correction while simultaneously preserving spinal, trunk, and lung growth. This study introduces a new surgical strategy, called the modified growing rod technique, which allows spinal growth and lung development while controlling the main deformity with apical and intermediate anchors without fusion. The use of intraoperative traction at the initial procedure enables spontaneous correction of the deformity and decreases the need for forceful correction maneuvers on the immature spine and prevents possible implant failures. This study seeks to evaluate (1) curve correction; (2) spinal length; (3) number of procedures performed; and (4) complications with the new approach.

DESCRIPTION OF TECHNIQUE

In the initial procedure, polyaxial pedicle screws were placed with a muscle-sparing technique. Rods were placed in situ after achieving correction with intraoperative skull-femoral traction. The most proximal and most distal screws were fixed and the rest of the screws were left with nonlocked set screws to allow vertical growth. The lengthening reoperations were performed every 6 months.

METHODS

Between 2007 and 2011, we treated 19 patients surgically for early-onset scoliosis. Of those, 16 (29%) were treated with the modified growing rod technique by the senior author (AH); an additional three patients were treated using another technique that was being studied at the time by one of the coauthors (CO); those three were not included in this study. The 16 children included nine girls and seven boys (median, 5.5 years of age; range, 4-9 years), and all had progressive scoliosis (median, 64°; range, 38°-92°). All were available for followup at a minimum of 2 years (median, 4.5 years; range, 2-6 years).

RESULTS

The initial curve Cobb angle of 64° (range, 38°-92°) improved to 21° (range, 4°-36°) and was maintained at 22° (range, 4°-36°) throughout followup. Preoperative thoracic kyphosis of 22° (range, 18°-46°) was maintained at 23° (range, 20°-39°) throughout followup without showing any substantial change. There was a 47 mm (range, 38-72 mm) increase in T1-S1 height throughout followup. The mean number of lengthening operations was 5.5 (range, 4-10). The mean T1-S1 length gain from the first lengthening was 1.18 cm (range, 1.03-2.24 cm) and decreased to 0.46 cm (range, 0,33-1.1 cm) after the fifth lengthening procedure (p = 0.009). The overall complication rate was 25% (four of 16 patients) and the procedural complication rate was 7% (seven of 102 procedures). We did not experience any rod breakages or other complications apart from two superficial wound infections managed without surgery during the treatment period. The only implant-related complications were loosening of two pedicle screws at the uppermost foundation in one patient.

CONCLUSIONS

In this preliminary study, the modified growing rod technique with apical and intermediate anchors provided satisfactory curve control, prevented progression, maintained rotational stability, and allowed continuation of trunk growth with a low implant-related complication rate.

Bilateral rib-to-pelvis Eiffel Tower VEPTR construct for children with neuromuscular scoliosis: a preliminary report

BACKGROUND CONTEXT

Neuromuscular scoliosis could develop at a young age and progress beyond skeletal maturity. An early spinal fusion arrests growth of the spine and thorax, risking the development of secondary thoracic insufficiency syndrome. Vertical expandable prosthetic titanium rib (VEPTR) is a fusionless technique aiming at correction of the deformity with preservation of growth potential.

PURPOSE

To demonstrate the preliminary results of the use of VEPTR in an Eiffel Tower construct in children with neuromuscular scoliosis in regard to coronal and sagittal profiles, space available for the lungs (SAL), and spinal growth. The report lists the complications we faced during the follow-up of 1.33 years after the index procedure.

STUDY DESIGN

A retrospective analysis of prospectively collected data of a case series.

PATIENT SAMPLE

Twenty nonambulatory children (mean 8.9 years) with neuromuscular scoliosis. Their primary diagnoses were myelomeningocele in seven, cerebral palsy in three, spinal muscular atrophy in two, myopathies in three, arthrogryposis in one, and syndromic scoliosis in four patients.

METHODS

All 20 patients received percutaneous rib-to-pelvis VEPTR implantation. Mean operative time was 2 hours, and mean hospital stay was 12 days. None of them needed blood transfusion. They underwent 20 primary implantations and 39 lengthenings.

OUTCOME MEASURES

The patients were assessed based on physiologic measures, that is, the radiographic improvement of their scoliosis, SAL, pelvic tilt, spinal height, and sagittal and coronal decompensation.

RESULTS

At the latest follow-up, thoracolumbar curvature improved significantly (65.7°±20.5° to 49.9°±15.7°), as did lumbar curvature (61.6°±19.5° to 35°±21.2°), thoracic (17.2±2.3 to 20±2.3 cm) and lumbar spinal height (9.9±1.7 to 11.9±1.8 cm), SAL (86.5±8.9 to 97±10), pelvic obliquity (12.5°±8° to 5.2°± 5.2°), and the iliolumbar angle (15°±8° to 10.06°±7.1°). Nine patients suffered complications in the form of proximal cradle migration (five), implant breakage (five), deep wound infection (three), and dislodged iliac hooks (two).

CONCLUSIONS

Early results of VEPTR for neuromuscular scoliosis are encouraging. Follow-up till skeletal maturity will best determine future indications.

Extraspinal ossifications after implantation of vertical expandable prosthetic titanium ribs (VEPTRs)

INTRODUCTION

Though developed for thoracic insufficiency syndrome, the spinal growth-stimulating potential and the ease of placement of vertical expandable titanium ribs (VEPTRs) has resulted in their widespread use for early-onset spine deformity. Observation of implant-related ossifications warrants further assessment, since they may be detrimental to the function-preserving non-fusion strategy.

PATIENTS AND METHODS

Radiographs (obtained pre and post index procedure, and at 4-year follow-up) and the records of 65 VEPTR patients from four paediatric spine centres were analysed. Ossifications were classified as type I (at anchor points), type II (along the central part) or type III (re-ossification after thoracostomy).

RESULTS

The average age at the index procedure was 6.5 years (min 1, max 13.7). The most prevalent spine problem was congenital scoliosis (37) with rib fusions (34), followed by neuromuscular and syndromic deformities (13 and 8, respectively). Idiopathic and secondary scoliosis (e.g. after thoracotomy) were less frequent (3 and 4, respectively). Forty-two of the 65 (65 %) patients showed ossifications, half of which were around the anchors. Forty-five percent (15/33) without pre-existing rib fusions developed a type II ossification along the implant. Re-ossifications of thoracostomies were less frequent (5/34, 15 %). The occurrence of ossifications was not associated with patient-specific factors.

CONCLUSIONS

Implant-related ossifications around VEPTR are common. In contrast to harmless bone formation around anchors, ossifications around the telescopic part and the rod section are troublesome in view of their possible negative impact on chest cage compliance and spinal mobility. This potential side effect needs to be considered during implant selection, particularly in patients with originally normal thoracic and spinal anatomy.

Complications in pediatric spine surgery using the vertical expandable prosthetic titanium rib: the French experience

STUDY DESIGN

Multicenter retrospective study of 54 children.

OBJECTIVE

To describe the complication rate of the French vertical expandable prosthetic titanium rib (VEPTR) series involving patients treated between August 2005 and January 2012.

SUMMARY OF BACKGROUND DATA

Congenital chest wall and spine deformities in children are complex entities. Most of the affected patients have severe scoliosis often associated with a thoracic deformity. Orthopedic treatment is generally ineffective, and surgical treatment is very challenging. These patients are good candidates for VEPTR expansion thoracoplasty. The aim of this study was to evaluate the potential complications of VEPTR surgery.

METHODS

Of the 58 case files, 54 were available for analysis. The series involved 33 girls and 21 boys with a mean age of 7 years (range, 20 mo-14 yr and 2 mo) at primary VEPTR surgery. During the follow-up period, several complications occurred.

RESULTS

Mean follow-up was 22.5 months (range, 6-64 mo). In total, 184 procedures were performed, including 56 VEPTR implantations, 98 expansions, and 30 nonscheduled procedures for different types of complications: mechanical complications (i.e., fracture, device migration), device-related and infectious complications, neurological disorders, spine statics disturbances. Altogether, there were 74 complications in 54 patients: a complication rate of 137% per patient and 40% per surgery. Comparison of the complications in this series with those reported in the literature led the authors to suggest solutions that should help decrease their incidence.

CONCLUSION

The complication rate is consistent with that reported in the literature. Correct determination of the levels to be instrumented, preoperative improvement of nutritional status, and better evaluation of the preoperative and postoperative respiratory function are important factors in minimizing the potential complications of a technique that is used in weak patients with complex deformities.