Thoracic malformation with early-onset scoliosis: effect of serial VEPTR expansion thoracoplasty on lung growth and function in children

Ovine model of congenital chest wall and spine deformity: From birth to 3 months follow-up

Background

The evolution and treatment of lung alterations related to congenital spine and chest wall deformities (CWD) are poorly understood. Most animal models of CWD created postnatally were not evaluated for respiratory function. The goal of our study was to evaluate the effects of a CWD induced in utero on lung growth and function in an ovine model.

Methods

A CWD was induced in utero at 70-75 days of gestation in 14 ovine fetuses by resection of the 7th and 8th left ribs. Each non-operated twin fetus was taken as control. Respiratory mechanics was studied postnatally in the first week and at 1, 2, and 3 months. Post-mortem respiratory mechanics and lung histomorphometry were also assessed at 3 months.

Results

Eight out of 14 CWD lambs (57%) and 14 control lambs survived the postnatal period. One severe and five mild deformities were induced. At birth, inspiratory capacity (25 vs. 32 mL/kg in controls), and dynamic (1.4 vs. 1.8 mL/cmH2O/kg), and static (2.0 vs. 2.5 mL/cmH2O/kg) respiratory system compliances were decreased in CWD lambs. Apart from a slight decrease in inspiratory capacity at 1 month of life, no other differences were observed in respiratory mechanics measured in vivo thereafter. Postmortem measurements found a significant decrease in lung compliance-for each lung and for both lungs taken together-in CWD lambs. No differences in lung histology were detected at 3 months in CWD animals compared to controls.

Conclusions

Our study is the first to assess the effects of a prenatally induced CWD on lung development and function from birth to 3 months in an ovine model. Our results show no significant differences in lung histomorphometry at 3 months in CWD lambs compared to controls. Resolution at 1 month of the alterations in respiratory mechanics present at birth may be related to the challenge in inducing severe deformities.

Early Onset Scoliosis and Adolescent Idiopathic Scoliosis: A Review of the Literature and Correlations With Pulmonary Dysfunction

In the management of early onset scoliosis (EOS) and adolescent idiopathic scoliosis (AIS), orthopedic surgeons are tasked with considering the effects that curves and their treatment can have on the respiratory system, possibly the most relevant being pulmonary dysfunction due to thoracic cage changes. The pulmonary impairment that occurs as a result of scoliosis varies widely and requires a multimodal response, including physiologic testing, such as pulmonary function tests (PFTs) and consistent psychosocial monitoring of the patient. This forces healthcare providers to consider all factors affecting the patient's quality of life (QOL) and not just the primary pathology they are treating. One method that could be utilized to ensure a more holistic approach to treatment is the use of patient-reported outcome measures (PROMs) to assess the QOL domains. Thus, this review serves to highlight the importance of addressing and correcting pulmonary dysfunction in the care of children with EOS and AIS in a holistic manner.

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.

Factors Associated with Postoperative Respiratory Complications following Posterior Spinal Instrumentation in Children with Early-onset Scoliosis

Objective

To investigate the incidence and risk factors of postoperative respiratory complications (PRCs) in children with early‐onset scoliosis (EOS) following posterior spine deformity surgery (PSDS) based on growth‐friendly techniques, so as to help improve the safety of surgery.

Methods

A retrospective study of children with EOS admitted for PSDS based on growth‐friendly techniques from October 2013 to October 2018 was reviewed at a single center. There were 73 children (30 boys, 43 girls) who fulfilled the criteria in this research. The mean age of the patients was 7 ± 6.2 years. Patients were divided into the groups with and without PRCs. Variables that might affect the PRCs during the perioperative period, including general factors, radiographic factors, laboratory factors and surgical factors, were analyzed using univariate analysis to evaluate the potential risk factors. The variables that were significantly different were further analyzed by binary logistic regression analysis to identify the independent factors of PRCs.

Results

All the 73 children included 42 idiopathic scoliosis (57.5%), 12 congenital scoliosis (16.4%), 10 syndromic scoliosis (13.7%) and nine neuromuscular scoliosis (12.3%). PRCs were detected in 16 children (21.9%) with nine different PRCs. The total frequency of detected PRCs was 54, including pleural effusion (25.9%), postoperative pneumonia (20.4%), hypoxemia (18.5%), atelectasis (14.8%), prolonged intubation with mechanical positive pressure ventilatory support (PIMPPVS) (7.4%), bronchospasm (3.7%), reintubation (3.7%), delayed extubation (3.7%) and pneumothorax (1.9%). Results of univariate testing demonstrated that the following six variables were statistically different (P < 0.05): nonidiopathic scoliosis, combined with pulmonary comorbidities, pretransferrin < 200 mg/dL, prealbumin < 3.5 g/dL, anesthesia time ≥ 300 min and blood loss to total blood volume ratio (BL/TBV) ≥ 15%. Binary logistic regression analysis confirmed that BL/TBV≥15% (odd ratio OR = 29.188, P = 0.010), combined with pulmonary comorbidities (OR = 19.216, P = 0.012), pretransferrin < 200 mg/dL (OR = 11.503, p = 0.024), and nonidiopathic scoliosis (OR = 7.632, P = 0.046) were positively linear correlated with PRCs in children with EOS following PSDS.

Conclusion

PRCs has a higher incidence in children with EOS following PSDS. BL/TBV ≥15%, combined with pulmonary comorbidities, pre‐transferrin < 200 mg/dL, and nonidiopathic scoliosis play an important role for the development of PRCs in this population.

55th Harrington Lecture: The respiratory impact of EOS and its therapies: where are we and where do we go from here?

The following lecture was delivered at the Scoliosis Research Society annual meeting in 2020. It addresses our current knowledge about the respiratory impact of Early Onset Scoliosis, the limitations in the data that have been published, and the opportunity for further clinical research in the field.

Growing-rod Graduates With Idiopathic Early-onset Scoliosis Have Comparable Exercise Tolerance to Patients With Surgically Treated Adolescent Idiopathic Scoliosis

BACKGROUND

Growing-rod (GR) treatment is the current standard for progressive idiopathic early-onset scoliosis (I-EOS) in young children. Despite good radiographic outcomes, the impact of scoliosis treatment on pulmonary functions is not well-defined in this patient population. The aim of this study was to evaluate pulmonary functions and exercise tolerance in I-EOS patients graduated from GR treatment and to compare them with age-matched, surgically treated adolescent idiopathic scoliosis (AIS) patients and healthy controls.

METHODS

Eight GR graduates with I-EOS with pulmonary function tests and complete radiographic results were compared with a group of 9 thoracic AIS patients at least 2 years out from posterior fusion. Both groups were also compared with a set of 10 healthy individuals. All subjects underwent cardiopulmonary exercise testing and spirometry to evaluate pulmonary function.

RESULTS

Age, sex, height, arm span, weight, residual deformity, and level of instrumentation in GR and AIS patients were similar. In the GR group, forced vital capacity % and forced expiratory volume in 1 second % values were reduced compared with the healthy controls and AIS group (P<0.001, <0.001 and 0.036, 0.046, respectively). Breathing reserve index at lactate threshold (BRILT) was higher in GR and AIS patients (P=0.001 and 0.002, respectively), and was similar between GR and AIS patients (P=0.916). Heart rate at lactate threshold was higher in GR and AIS groups compared with controls (P<0.001 and 0.001, respectively).

CONCLUSIONS

AIS and GR patients demonstrated reduced pulmonary reserve and exercise tolerance compared with their peers with no spinal deformity. However, exercise tolerance of I-EOS patients treated with the GR method was similar to that of operated AIS patients. These results suggest a positive impact of GR treatment in children with I-EOS.

LEVEL OF EVIDENCE

Level III-cross-sectional comparative study.

Comparison of T1-S1 Spine Height of Postoperative Rib-based Implant Patients With Age-matched Peers

BACKGROUND

Severe early-onset scoliosis leads to deficient spine height, thoracic growth inhibition, and ultimately pulmonary compromise. Rib-based growing instrumentation seeks to correct thoracic deformities, in part by correcting the spinal deformity, adding height, increasing thoracic volume, and allowing for continual spinal growth until maturity. However, the amount of growth in these patients relative to their peers is unknown.

METHODS

Sixty patients who had undergone surgical intervention for the treatment of early-onset scoliosis were assessed via radiographic measurements of coronal T1-S1 height and major curve angle before implantation and again at most recent follow-up (minimum 2 years). T1-S1 measurements were then compared with age-matched peers to assess growth differences. Clinical information was examined for relevant parameters.

RESULTS

The average age of our cohort at initial surgery and most recent follow-up was 4.4±3.8 and 10.0±4.4 years old, respectively. In this patient set, there was an average increase in T1-S1 height of 13.1±11.1 mm per year, with the majority of growth occurring in the first 2 years following implantation, and improvement in a major curve from 68±8 to 53±7 degrees. Overall, 77% of patients saw improvement in the major curve at most recent follow-up. Furthermore, a statistically significant greater percent of expected growth was seen in congenital compared with neuromuscular scoliosis (P<0.001). In addition, a weak negative correlation was observed between a number of surgical lengthenings and T1-S1 growth.

CONCLUSIONS

Rib-based implant intervention has been shown to improve the major curve, but only improves growth potential to around 80% of expected growth. Scoliosis diagnosis type also influences growth rate potential, with congenital scoliosis patients being surgically treated earlier in life and having a growth rate approaching that of a healthy individual.

LEVEL OF EVIDENCE

Level III-Case control.

Clinical Issues for Pediatric Pulmonologists Managing Children With Thoracic Insufficiency Syndrome

Thoracic insufficiency Syndrome (TIS) is a recently coined phrase to describe children with spine and chest wall deformities, inherited and acquired, who have respiratory impairment, and are skeletally immature. This population has both restrictive and less often obstructive lung disease due to changes in spine and rib configuration which reduce lung volume, stiffen the chest wall, and reduce respiratory muscle strength. Although the population is heterogeneous with regard to age of onset, etiology, severity of deformity, and rate of progression of the deformity, there are common issues that arise which can be addressed by pediatric pulmonologists. These are illustrated in this review by using Early Onset Scoliosis as a common form of TIS. The pulmonary issues pertaining to TIS require collaboration with multi-disciplinary teams, particularly spine surgeons, in order to make decisions about non-surgical and surgical strategies, timing of surgery and medical supportive care over time. Pulmonary input about respiratory function should be used in conjunction with structural features of each deformity in order to determine the impact of the deformity and the response to various treatment options. In those patients with residual lung function impairment as young adults, pediatric pulmonologists must also ensure successful transition to adult care.

VEPTR Treatment of Early Onset Scoliosis in Children Without Rib Abnormalities: Long-term Results of a Prospective, Multicenter Study

BACKGROUND

In 2007, this prospective study on vertical expandable prosthetic titanium rib (VEPTR) treatment of early onset scoliosis in children without rib abnormalities was initiated. Two-year follow-up results have previously been reported. This study examines whether, at 5-year follow-up, VEPTR continues to control scoliosis and allow spinal growth.

METHODS

A prospective, multicenter, observational cohort design was used. Patients underwent traditional VEPTR implantation ≥5 years before analysis. Preimplantation and last available images were compared, regardless of whether VEPTR remained in vivo. Additional analysis was performed if VEPTR was in vivo ≥5 years.

RESULTS

This study included 59 patients (mean age at VEPTR implantation, 6.1±2.4 y; mean follow-up, 6.9±1.4 y). Currently, 24 patients still have VEPTR, whereas 24 have converted (13 fusions, 6 MCGR, 3 growing rods, 1 hybrid, and 1 Shilla). Three have had VEPTR explanted, 6 are unknown, and 2 have deceased. On last available imaging (n=59; mean follow-up, 4.8±1.9 y), scoliosis improved from 71.8±18.0 degrees preoperatively to 60.9±20.3 degrees (P<0.001) and T1- T12 height increased (15.8±3.2 to 19.3±3.8 cm, P<0.001). T1-S1 height also increased (24.8±4.4 to 31.2±5.3 cm, P<0.001), representing 119% age-matched growth. Composite improvement of scoliosis, T1-T12, and T1-S1 height was achieved in 79% of patients. A subset of 29 patients with VEPTR was analyzed at most recent follow-up ≥5 years while VEPTR remained in vivo (24 patients with VEPTR above, and 5 who later converted to other devices). Mean age at implantation was 5.0±2.2 years, with a mean VEPTR treatment duration of 6.2±1.1 years. Scoliosis improved from preoperatively (69.3±14.5 to 61.6±16.1 degrees, P=0.006), with mild recurrence from postoperative to 5 years. T1-T12 height increased (15.0±3.3 to 18.7±3.3 cm, P<0.001) and T1-S1 height increased (23.7±4.5 to 30.1±4.6 cm, P<0.001), representing 83% age-matched growth. Composite improvement was achieved in 83% of patients. Instrumented sagittal length also increased during this period (21.8±4.2 to 30.3±5.1 cm, P<0.001).

CONCLUSION

At a 5-year follow-up, VEPTR continues to control scoliosis and allow spinal growth.

LEVEL OF EVIDENCE

Level II-prospective cohort, therapeutic study.

Persistence and Progression of Airway Obstruction in Children With Early Onset Scoliosis

BACKGROUND

Obstructive lung disease occurs in 30% of children with early onset scoliosis (EOS); changes in degree of airway obstruction over time have not been reported.

METHODS

Longitudinal patterns of incidental, persistent, and progressive airway obstruction were retrospectively analyzed in a cohort of children with EOS with at least 1 forced expiratory volume in 1 second (FEV1)/forced vital capacity (FVC) value <85% on serial spirometric assessments over a ≥3-year observation period. The prevalence of clinical features and the severity of coronal and sagittal spine deformities for each group at the beginning and end of the study period were compared.

RESULTS

Airway obstruction was incidental in 12 (24%) and persistent in 37 (76%) of 49 children with EOS. Twenty of 37 (54%) of those with persistent obstruction developed progressive airway obstruction. The decline in FEV1/FVC over 6±2 years was insignificant in the incidental group (4%±2%) and the persistent nonprogressive group (7%±4%) but significant in the progressive group (13%±4%, t test; P=0.002). In total, 29% of the 49 children at the onset and 57% at the end of the study had airway obstruction. The incidental, persistent nonprogressive, and progressive groups did not differ with regard to age, diagnosis distribution, or sex. The initial coronal curve size, apex, direction of the curve, and degree of kyphosis were statistically similar among the 3 groups. Coronal curve magnitude inversely correlated with FEV1/FVC at the end but not the beginning of the study (r=-0.19, P=0.002). Six of 19 responded to bronchodilator treatment, suggesting concurrent asthma. Airway obstruction did not relate to restrictive pulmonary abnormalities measured by FVC at first or last timepoints [slope=-0.076 (95% confidence interval, -0.99 to 0.038; P=0.19)]. Changes in degrees of airway obstruction and restrictive lung disease over time did not correlate [slope=-0.125 (95% confidence interval, -0.294 to 0.044; P=0.14)].

CONCLUSIONS

Children with EOS and progressive airway obstruction represent an important subgroup which may require new surgical and nonsurgical treatment strategies to prevent loss of lung function over time.

The Effect of Expansion Thoracostomy on Spine Growth in Patients with Spinal Deformity and Fused Ribs Treated with Rib-Based Growing Constructs

STUDY DESIGN

Retrospective review of prospective registries.

OBJECTIVES

We hypothesized that patients with congenitally fused ribs who underwent thoracostomy upon implantation of rib-based distraction devices would achieve improved spine growth compared with those who did not undergo thoracostomy.

SUMMARY OF BACKGROUND DATA

Patients with fused ribs may develop thoracic insufficiency syndrome. Treatment for severe early-onset spinal deformity with rib fusions often includes the placement of rib-based expansion devices with surgical division of the fused ribs (thoracostomy). The effect of thoracostomy on spinal growth has not been fully examined.

METHODS

Two multicenter registries of primarily prospectively collected data were searched. Patients with fused ribs and implantation of a rib-based device were identified. A total of 151 patients with rib fusions treated with rib-based constructs and minimum two-year follow-up were included. Among those, 103 patients were treated with expansion thoracostomy at the time of implantation, whereas 48 patients received device implantation alone. We evaluated change in T1-T12 and T1-S1 height, coronal Cobb angle, kyphosis, and number of surgeries. Preoperative deformity was similar between the two groups. Only 19% of patient underwent final fusion, with similar numbers fused in each group.

RESULTS

At latest follow-up, the expansion thoracostomy group had a greater total improvement in T1-S1 height (7.2 cm vs. 4.8 cm, p = .004). There was no difference between the two groups for change in spinal height at each lengthening procedure. Interestingly, thoracostomy patients also underwent more total surgeries (11.5 vs. 9.6, p = .031) and more lengthening procedures (8.3 vs. 6.6, p = .017) than the comparison group despite similar length of follow-up.

CONCLUSIONS

Patients who underwent expansion thoracostomy at the time of rib expansion device implantation achieved greater improvement in T1-S1 height than those who underwent implantation of rib expansion device alone. Further work is needed to evaluate whether expansion thoracostomy impacts pulmonary function.

Long-term Outcome of Early Fusions for Congenital Scoliosis

STUDY DESIGN

The current literature on outcomes of early fusions for early-onset scoliosis (EOS) has a short follow-up of 7.7 to 12.5 years, with many patients not at the end of growth. The forced vital capacity (FVC) at follow-up ranged from 40.8% to 64% of predicted. A study was undertaken to evaluate the long-term outcome of these fusions.

METHODS

The study is of congenital patients who had a fusion under age 8 years, with the current age being >20 years. A follow-up consisting of radiographs, outcome questionnaires, and pulmonary function tests was performed. Of the 42 patients identified, 20 were traced and 11 agreed to participate, and completed all the data. The average follow-up was 37 years. All the fusions included the thoracic spine, with an average of 10.2 levels fused, of which an average of 8.8 levels were thoracic.

RESULTS

The average scoliosis at presentation was 52°, 56° at surgery and 47° at follow-up. At follow-up, the average FVC was 53% of predicted, with an average PaO₂ of 86 and PaCO₂ of 44 mm Hg. The mean T1-T12 length was 20 cm. There was no correlation of the FVC percentage predicted and the proximal extent of the fusion, the T1-T12 length or the number of thoracic levels fused. The average ODI was 23. On the SF36, the average Physical Component t score was 50; with the average Mental Component t score was 52.

CONCLUSION

At a long-term average follow-up of 37 years, the patients had a low FVC of 53%, with one on permanent oxygen and 5 with dyspnea. The patients were functioning well at follow-up, but it is unknown what their function would be without surgery or with longer follow-up.

VEPTR: Are We Reducing Respiratory Assistance Requirements?

BACKGROUND

The assisted ventilation rating (AVR) indicates the degree of external respiratory support required in children with thoracic insufficiency syndrome (TIS) and early onset scoliosis. For skeletally immature patients with TIS, the vertical expandable prosthetic titanium rib (VEPTR) device can be used to improve lung volume and growth. We hypothesized that patients who underwent early thoracic reconstruction by VEPTR treatment had an improved respiratory status.

METHODS

Preoperative and postoperative AVR ratings were prospectively collected in a multicenter study group and compared to determine change after VEPTR treatment. Patients under 10 years of age at initial implant with minimum of 2-year follow-up data were included. Patients were excluded if there were incomplete data or if initial AVR was normal (breathing on room air). Statistical analysis was performed on groups which had stable, declined, and improved AVR at final follow-up.

RESULTS

Database search yielded 77 patients with initial abnormal AVR. Average follow-up was 5.6 years. The most frequent primary diagnoses were congenital scoliosis (n=14) and spinal muscular atrophy (n=14). In total, 19 (24%) demonstrated improvement, 9 (12%) patients deteriorated, and 49 (64%) remained at the same level. The average preoperative major curve in those with improvement (58.4 degrees) and those with no change (63.5 degrees) was less than in those with deterioration (85.5 degrees) (P=0.014). The average age in years at implant of those with improvement (4) was less than those declined (6.7) and those with no change (5.5). In total, 16 (84.2%) of those that improved had a normal AVR and did not require respiratory support at last follow-up.

CONCLUSIONS

There is evidence that a subset of patients with early onset scoliosis and TIS who received early thoracic reconstruction with VEPTR treatment show complete resolution of pulmonary support at final follow-up. In total, 89% of 79 patients did not experience respiratory deterioration. A total of 24% (n=19) had a positive change with over 84% (n=16) of this group no longer requiring support.

LEVEL OF EVIDENCE

Level III-prognostic.

A comprehensive review of the diagnosis and management of congenital scoliosis

PURPOSE

To provide the reader with a comprehensive but concise understanding of congenital scoliosis METHODS: We have undertaken to summarize available literature on the pathophysiology, epidemiology, and management of congenital scoliosis.

RESULTS

Congenital scoliosis represents 10% of pediatric spine deformity and is a developmental error in segmentation, formation, or a combination of both leading to curvature of the spine. Treatment options are complicated by balancing growth potential with curve severity. Often associated abnormalities of cardiac, genitourinary, or intraspinal systems are concurrent and should be evaluated as part of the diagnostic work-up. Management balances the risk of progression, growth potential, lung development/function, and associated risks. Surgical treatment options involve growth-permitting systems or fusions.

CONCLUSION

Congenital scoliosis is a complex spinal problem associated with many other anomalous findings. Treatment options are diverse but enable optimization of management and care of these children.

Early-onset Scoliosis: Contemporary Decision-making and Treatment Options

Early-onset scoliosis (EOS) describes a wide array of diagnoses and deformities exposed to growth. This potentially life-threatening condition is still 1 of the biggest challenges in pediatric orthopaedics. The enlightenment of Bob Campbell's thoracic insufficiency syndrome concept and the negative impact of the earlier short and straight spine fusion approach on respiratory function and survival have fueled the evolution of EOS care. Despite all the progress made, growth-friendly spine surgery remains to be a burden to patients and caregivers. Even down-sized implants and remote-controlled noninvasive rod expansions do not omit unexpected returns to the operating room: failures of foundations, rod breakage, difficulties to keep the sagittal balance, progressive transverse plane deformities, stiffening, and the need for final instrumented fusion are still common. However, past experience and the current multitude of surgical strategies and implants have sharpened the decision-making process, patients with thoracic insufficiency syndrome require earliest possible vertical expandable prosthetic titanium ribs application. Flexible deformities below 60 degrees, with normal spinal anatomy and without thoracic involvement, benefit from serial Mehta casting which revived as a long available but not-used strategy. In case of progression, standard double growing rods or-if available, affordable, and applicable-magnetically controlled motorized rods provide deformity control and growth promotion. Shilla growth-guiding technique is a less costly alternative. Its lack of stiff lengthening boxes or actuators may be beneficial in difficult deformities. Anterior convex flexible tethering promises benefits of sparing the trunk muscles and keeping mobility. However, this step towards a true nonfusion concept has yet to stand the test of broad clinical application.

An NIHR-approved two-year observational study on magnetically controlled growth rods in the treatment of early onset scoliosis

Aims

The primary aim of this study was to evaluate the performance and safety of magnetically controlled growth rods in the treatment of early onset scoliosis. Secondary aims were to evaluate the clinical outcome, the rate of further surgery, the rate of complications, and the durability of correction.

Patients and Methods

We undertook an observational prospective cohort study of children with early onset scoliosis, who were recruited over a one-year period and followed up for a minimum of two years. Magnetically controlled rods were introduced in a standardized manner with distractions performed three-monthly thereafter. Adverse events which were both related and unrelated to the device were recorded. Ten children, for whom relevant key data points (such as demographic information, growth parameters, Cobb angles, and functional outcomes) were available, were recruited and followed up over the period of the study. There were five boys and five girls. Their mean age was 6.2 years (2.5 to 10).

Results

The mean coronal Cobb angle improved from 57.6° (40° to 81°) preoperatively, 32.8° (28° to 46°) postoperatively, and 41° (19° to 57°) at two years. Five children had an adverse event, with four requiring return to theatre, but none were related to the device. There were no neurological complications or infections. No devices failed. One child developed a proximal junctional kyphosis. The mean gain in spinal column height from T1 to S1 was 45.4 mm (24 to 81) over the period of the study.

Conclusion

Magnetically controlled growth rods provide an alternative solution to traditional growing rods in the surgical management of children with early onset scoliosis, supporting growth of the spine while controlling curve progression. Their use has clear psychosocial and economic benefits, with the reduction of the need for repeat surgery as required with traditional growing rods. Cite this article: Bone Joint J 2018;100-B:507-15.

Maximal Respiratory Muscle Strength and Vital Capacity in Children With Early Onset Scoliosis

STUDY DESIGN

Descriptive cross-sectional study.

OBJECTIVE

To measure respiratory muscle function in children with early onset scoliosis (EOS), determine the frequency of respiratory muscle weakness, and correlate these measures with vital capacity, body mass index, and Cobb angle.

SUMMARY OF BACKGROUND DATA

Progressive restrictive respiratory disease is common among children with moderate to severe EOS. Reduced respiratory muscle strength is associated with the loss of lung function in adolescents and adults with scoliosis. We hypothesized that reduced inspiratory and expiratory respiratory muscle strength also occur in children with EOS and correlate with reduced vital capacity, poor nutritional status, and severity of the spine deformity.

METHODS

We measured maximum inspiratory pressure (MIP) and maximum expiratory pressure (MEP), forced vital capacity (FVC), body mass index IBMI), and Cobb angle in 49 children with EOS but with no diagnosis of underlying muscle weakness. We measured these indices in 12 children serially over 18 months to see if abnormal respiratory muscle function was sustained.

RESULTS

FVC averaged 51% (SD 21) of predicted norms with 26 subjects having an FVC <50% predicted. The mean MIP was 57% (SD 25) and the mean MEP was 53% (SD 23) of predicted norms. Thirteen (27%) of the group had MIP values >2SD below the age and sex-based norms. BMI ranged between 1% and 99% of age-based norms. Cobb angle averaged 59° (SD27). MIP% and MEP% significantly correlated with FVC% (r =0.37, P = 0.01 and r = 0.52, P < 0.001 respectively)) but not with BMI or Cobb angle. Reduced MIP% and MEP% were sustained over 7 to 41 months.

CONCLUSION

Respiratory muscle weakness is common and persistent in children with EOS and correlates with reductions in vital capacity. Mechanisms for abnormal respiratory function are unclear but must be determined to develop surgical treatment strategies that preserve respiratory muscle function in children with EOS throughout childhood.

LEVEL OF EVIDENCE

2.

Complications in using the vertical expandable prosthetic titanium rib (VEPTR) in children

PURPOSE

This report describes complications using the vertical expandable prosthetic titanium rib (VEPTR) for thoracic insufficiency syndrome (TIS) at a single center.

METHODS

This is a prospective cohort evaluating 65 patients with rib-rib and rib-spine VEPTR devices for TIS placed between 10/2001 and 11/2014, for children with spinal or chest wall deformity. Patients were classified using the early onset scoliosis classification system (C-EOS).

RESULTS

65 patients are available for follow up. 23 congenital scoliosis, 12 neuromuscular, 14 syndromic, 2 idiopathic and 14 not classifiable by the C-EOS system including 11 chest wall reconstructions. Average age at implantation was 6.9years (range 1.3-24.8) with average follow up 6.9years (range 0.4-14.8). 22 patients had 37 complications. Those classifiable by C-EOS had complications in the normo- and hyperkyphotic groups. Implant erosion and infection were most common. The majority of complications required one additional unplanned surgery for resolution. Two complications required abandonment of a growth-friendly strategy.

CONCLUSIONS

Use of VEPTR for TIS is associated with significant and frequent complications. C-EOS suggests that complications are more likely in those with normal or hyperkyphotic curves. Most complications are managed with one unplanned surgery. VEPTR is usually salvaged and abandonment of a growth-friendly strategy is unusual.

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.

A classification of growth friendly spine implants

BACKGROUND

Various types of spinal implants have been used with the objective of minimizing spinal deformities while maximizing the spine and thoracic growth in a growing child with a spinal deformity.

PURPOSE

The aim of this study was to describe a classification system of growth friendly spinal implants to allow researchers and clinicians to have a common language and facilitate comparative studies. Growth friendly spinal implant systems fall into 3 categories based upon the forces of correction the implants exert on the spine, which are as follows: Distraction-based systems correct spinal deformities by mechanically applying a distractive force across a deformed segment with anchors at the top and bottom of the implants, which commonly attach to the spine, rib, and/or the pelvis. The present examples of distraction-based implants are spine-based or rib-based growing rods, vertical expandable titanium rib prosthesis, and remotely expandable devices. Compression-based systems correct spinal deformities with a compressive force applied to the convexity of the curve causing convex growth inhibition. This compressive force may be generated both mechanically at the time of implantation, as well as over time resulting from longitudinal growth of vertebral endplates hindered by the spinal implants. Examples of compression-based systems are vertebral staples and tethers. Guided growth systems correct spinal deformity by anchoring multiple vertebrae (usually including the apical vertebrae) to rods with mechanical forces including translation at the time of the initial implant. The majority of the anchors are not rigidly attached to the rods, thus permitting longitudinal growth over time as the anchors slide over the rods. Examples of guided growth systems include the Luque trolley and Shilla.

CONCLUSIONS

Each system has its benefits and shortcomings. Knowledge of the fundamental principles upon which these systems are based may aid the clinician to choose an appropriate treatment for patients. Having a common language for these systems may aid in comparative research. Vertical expandable titanium rib prosthesis is used with humanitarian exemption. The other devices mentioned in this manuscript are not approved for growing constructs by the Food and Drug Administration and are used off-label.

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.

Primary thoraco-spinal disorders of childhood

Primary structural deformities of the spine and thorax were at one time rare and reportable in case series. With the development of new "growth friendly" implantable devices, children with these disorders are living longer and receiving both surgical and pulmonary care. As a result, there has been growing interest in the functional cardiopulmonary consequences of these deformities, the current surgical and non-surgical treatments, and the role of long-term supportive care. This article reviews current literature in this rapidly changing field, where new devices are developed and outcomes are changing. The respiratory consequences of early-onset thoraco-spinal disorders are emphasized and the roles of the pulmonologist and surgeons are discussed. There are more questions than answers as no long-term outcome data yet exists.

Early Onset Scoliosis: A Pulmonary Perspective

Early-onset scoliosis impairs lung function, often severely as it progresses. This review depicts current understanding of the changes in respiratory function resulting from early-onset scoliosis and how pulmonologists and their assessment tools affect clinical treatment decisions by spine surgeons.

[Non-fusion techniques for treatment of pediatric scoliosis]

The primary goal of treatment in children with early onset scoliosis (EOS) is to control the deformity and to allow spinal and chest wall growth to continue and improve pulmonary function. In skeletally immature children spondylodesis leads to fusion of the instrumented segments with associated nonsymmetrical growth and pulmonary insufficiency. Non-fusion, techniques such as growing rods, vertical expandable prosthetic titanium rib® (VEPTR) and staples have evolved over the past years. Each technique has its different spectrum of indications which the surgeon has to follow accurately to prevent the patient from developing complications. A new trend started by using magnetically controlled growing rods to avoid the need for anesthesia and open surgery during adaptive growth. The intention of this article is to give the reader a synopsis about the three most important non-fusion techniques based on own experience and the current literature.

Recent advances in the management of early onset scoliosis

As the undesired results of early spinal fusion have become apparent, "growth-friendly" management methods for early onset scoliosis have been increasing during recent years. Current literature supports the use of repeated corrective cast applications as the initial management for most early onset progressive spinal deformities as either definitive treatment or as a temporizing measure. If casting is not an option or the deformity cannot be controlled via casting, one of the growth-friendly instrumentation techniques is chosen. Growth-friendly surgical methods and implants have been evolving as understanding of the disease improves.

Chest wall abnormalities and their clinical significance in childhood

The thorax consists of the rib cage and the respiratory muscles. It houses and protects the various intrathoracic organs such as the lungs, heart, vessels, esophagus, nerves etc. It also serves as the so-called "respiratory pump" that generates the movement of air into the lungs while it prevents their total collapse during exhalation. In order to be performed these functions depend on the structural and functional integrity of the rib cage and of the respiratory muscles. Any condition (congenital or acquired) that may affect either one of these components is going to have serious implications on the function of the other. Furthermore, when these abnormalities occur early in life, they may affect the growth of the lungs themselves. The following article reviews the physiology of the respiratory pump, provides a comprehensive list of conditions that affect the thorax and describes their effect(s) on lung growth and function.

Wound complications of vertical expandable prosthetic titanium rib incisions

STUDY DESIGN

Multicenter retrospective review.

OBJECTIVE

To compare the incidence of infection between vertical expandable prosthetic titanium rib (VEPTR) incision locations and determine if the infection risk increases in relation to presence of previous incisions and/or increased number of times incisions are opened.

SUMMARY OF BACKGROUND DATA

Patients undergoing treatment for chest and spine deformity with VEPTR require multiple incisions that are opened repeatedly during expansion procedures.

METHODS

A prospective database (7 sites) and institutional database (2 sites), were queried to identify their 20 most recent patients with VEPTR with a minimum of 4 expansions for inclusion. A total of 103 patients were identified. Clinical and operative reports were reviewed to determine incision locations, number, and infection complications.

RESULTS

Twenty-five of 103 patients (24%) developed an infection during treatment. Six had multiple infections (range, 2-4), providing a total of 34 infection events. Patients averaged 6.4 expansion procedures and 13 total incisions. Infection rate at each incision site was not significantly different, in the range from 1% to 5%: paramedian (6 infections/23 patients with total 185 incisions, 3%), proximal midline (12/39; 224, 5%), thoracotomy (6/61; 455, 1%), iliac (5/37; 143, 4%), and distal midline (5/58; 148, 3%). Infection events occurred after an average of 3 times a particular incision was opened (95% confidence interval: 2.2-3.8). There was a trend toward higher infection rate with increased number of times a particular incision was opened. There was no increased infection rate in patients with surgical incisions prior to VEPTR (26%; 6/23) compared with patients not having prior incisions (24%; 19/80).

CONCLUSION

The incidence of infection in patients with 4 or more VEPTR lengthenings was 24% and did not differ across the various incision locations. Presence of prior surgical incisions was not a risk factor for infection. Surgeons should use the most appropriate incision in relation to their patient's pathology when using VEPTR while remaining vigilant for infection.

LEVEL OF EVIDENCE

3.

VEPTR to treat nonsyndromic congenital scoliosis: a multicenter, mid-term follow-up study

BACKGROUND

Traditional surgical management of multiple congenital vertebral anomalies in young children, including fusion in situ and hemiepiphyseodesis, do not promote spinal growth nor address the associated thoracic insufficiency syndrome. We hypothesize that vertical expandable prosthetic titanium rib (VEPTR) with expansion thoracoplasty may control spinal deformity, allow spinal growth, and address thoracic insufficiency syndrome in children with nonsyndromic complex congenital spinal deformities.

METHODS

Eight pediatric spine centers prospectively entered clinical and radiographic data into a database on every congenital spinal deformity treated with VEPTR as part of an Food and Drug Administration study. We retrospectively reviewed these data and excluded patients with spina bifida, Jarcho-Levin, or other syndromes. Data analysis focused on surgical technique and expansion frequency, change in Cobb angle and thoracic heights, and adverse events for a consecutive series of patients with at least 2 years of follow-up.

RESULTS

Twenty-four children with an average age at surgery of 3.3 years (range, 1.0 to 12.5 y) were treated with VEPTR insertion and expansion thoracostomy and were followed for an average of 40.7 months (range, 25 to 78 mo). Twenty-three (95.8%) had associated rib fusions. All patients had subsequent expansion surgery; 50% had 5 or more expansions. Twenty patients (83.3%) had an improvement in Cobb angle during treatment with an average improvement of 8.9 degrees. All had an increase in thoracic height, with a mean increase of 3.41 cm. The most common adverse events were device migration in 7 patients and infection or skin problems in 6 patients.

CONCLUSIONS

VEPTR insertion with expansion thoracoplasty represents a successful treatment paradigm for nonsyndromic congenital spinal deformities. We report multicenter data with midterm follow-up of children without syndromic diagnoses, in which the vast majority had an improvement in Cobb angle and thoracic height over the treatment period. Challenges include the demands of multiple procedures, skin problems, and device migration.

LEVEL OF EVIDENCE

Level IV-prognostic study.

Treatment of congenital thoracic scoliosis with associated rib fusions using VEPTR expansion thoracostomy: a surgical technique

INTRODUCTION

Untreated growing patients with congenital scoliosis and fused ribs will develop finally thoracic insufficiency syndrome. The technique of expansion thoracoplasty with implantation of a vertical expandable prosthetic titanium rib (VEPTR) was introduced initially to treat these children.

METHODS

This article attempts to provide an overview of the surgical technique of opening-wedge thoracostomy and VEPTR instrumentation in children with congenital thoracic scoliosis and fused ribs.

RESULTS

Our modification of the surgical approach using a posterior midline incision rather than the modified thoracotomy incision initially described could potentially help to diminish wound dehiscence and secondary infection, while preserving a more acceptable esthetic appearance of the back.

CONCLUSIONS

Vertical expandable prosthetic titanium rib-based treatments should be undertaken only with a good knowledge of its numerous specific complications. Every aspect of the treatment should be oriented to minimize these complications. At the same time it should be kept in mind that the ultimate step of this long-term fusionless treatment strategy will be a technically demanding spine fusion.

2014 Update on the 'growing spine surgery' for young children with scoliosis

PURPOSE OF REVIEW

Spinal fusion procedures that are the mainstay of the treatment of progressive or severe curves in adolescents and adults are not suitable for most young children as there is a large magnitude of remaining growth. Early spinal fusion stunts the growth of the thorax and may interfere with the development of the lungs. Therefore, in children with early-onset scoliosis, 'growth friendly' instrumentation systems have been utilized to control the deformity while allowing the growth of the spine and the thoracic cage.

RECENT FINDINGS

The experience with growing rods has been increasing, along with expanding indications. Several self-lengthening instrumentation systems have been introduced aiming for guided spinal growth. There has been considerable progress in the clinical and laboratory studies using magnetically controlled growing rod constructs. Growing rods and vertical expandable prosthetic titanium rib (VEPTR) systems provide deformity control while allowing for spinal growth along with a risk of spontaneous vertebral fusions. VEPTR may cause rib fusions as the implants overlie the thoracic cage and, therefore, the use in pure spinal deformities is controversial.

SUMMARY

There have been exciting recent advances concerning the treatment of spinal deformities in young children. Despite these advances, the surgical treatment of early-onset scoliosis remains far from optimal and more development is on the way.

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.

Evaluation of a Three-Dimensional Reconstruction Method of the Rib Cage of Mild Scoliotic Patients

STUDY DESIGN

Validation study.

OBJECTIVE

To evaluate a method of 3-dimensional (3D) reconstruction of the rib cage in a population of scoliotic patients.

SUMMARY OF BACKGROUND DATA

Evaluation of the thoracic cage clinical parameters would be helpful in the management of spinal deformities.

METHODS

Biplanar X-rays were performed using the EOS system and the rib cage was reconstructed using a previously developed semi-automated method. Thoracic parameters were calculated from the 3D reconstructions: volume, frontal and sagittal diameters, 3D spinal penetration index (SPI), thoracic index, and rib hump. To test accuracy, the authors constructed biplanar projections from 3 computed tomography scans and then used these projected X-rays as material for stereoradiographic reconstructions. The models were then compared with volumetric objects reconstructed from these 3 computed tomography scans. To test intra-observer and interobserver reproducibility, 22 chests (mean Cobb angle, 28° [range, 17° to 45°]) were reconstructed twice by 3 operators. The 95% confidence interval was calculated for the study parameters.

RESULTS

The mean signed point to surface distance was -1.6 mm. Interobserver reproducibility was 9 mm for maximum anteroposterior and lateral diameters, <0.8% for SPI, 5° for rib hump, .02 for thoracic index, and 450 cm³ for volume.

CONCLUSIONS

The results of the reproducibility study were satisfactory. The 95% confidence interval was <6% for the transverse diameters and <10% for volume and SPI. The reported method of 3D reconstruction of the rib cage provides accurate and reproducible determinations of the investigated thoracic parameters in scoliotic patients.

VEPTR: past experience and the future of VEPTR principles

PURPOSE

This review summarizes the experience with the vertical expandable prosthetic titanium rib (VEPTR) device, which enables five new procedures to treat complex spine and chest wall abnormalities in pediatric patients, which cause thoracic insufficiency syndrome, the inability of the thorax to support normal respiration or lung growth.

METHODS

The literature on VEPTR was reviewed and discussed by the author, the inventor of the VEPTR.

RESULTS

The central VEPTR treatment principle is to correct volume depletion deformity of the thorax, and maintain the correction until skeletal maturity, at which time procedures such as spinal fusion can be considered. For individual cases of complex deformity, VEPTR strategies can differ remarkably. The goal of VEPTR surgery is to pursue the surgical strategy that provides the largest, most symmetrical, most functional thorax that can grow as normally as possible. Assessment of these results is difficult, since natural history of VEPTR-treated diseases are not clearly known and no current imaging test can measure thoracic insufficiency syndrome, but dynamic lung MRI have promise for the future in better defining this potentially lethal condition.

CONCLUSION

VEPTR and its principles of use have become an important first step toward improving the quality of life and longevity of children with thoracic insufficiency syndrome, but much work remains to advance both its design and its use.

Advances in nonfusion techniques for the treatment of scoliosis in children

Scoliotic deformity in young children is a challenge for the spinal surgeon. Though traditional spinal correction and fusion techniques can improve these deformities, they inhibit growth of the spine. Nonfusion technologies are an effective approach to this problem. They not only correct the spinal deformity, but also allow the spine to keep growing and developing. These techniques include the growing rod, stapling, pedicle screw tethering, the vertical expandable prosthetic titanium rib (VEPTR), and multi-vertebrae wedge osteotomy. This is a review of advances in nonfusion techniques for the treatment of scoliosis in children.

What can imaging tell us about physiology? Lung growth and regional mechanical strain

The interplay of mechanical forces transduces diverse physico-biochemical processes to influence lung morphogenesis, growth, maturation, remodeling and repair. Because tissue stress is difficult to measure in vivo, mechano-sensitive responses are commonly inferred from global changes in lung volume, shape, or compliance and correlated with structural changes in tissue blocks sampled from postmortem-fixed lungs. Recent advances in noninvasive volumetric imaging technology, nonrigid image registration, and deformation analysis provide valuable tools for the quantitative analysis of in vivo regional anatomy and air and tissue-blood distributions and when combined with transpulmonary pressure measurements, allow characterization of regional mechanical function, e.g., displacement, strain, shear, within and among intact lobes, as well as between the lung and the components of its container-rib cage, diaphragm, and mediastinum-thereby yielding new insights into the inter-related metrics of mechanical stress-strain and growth/remodeling. Here, we review the state-of-the-art imaging applications for mapping asymmetric heterogeneous physical interactions within the thorax and how these interactions permit as well as constrain lung growth, remodeling, and compensation during development and following pneumonectomy to illustrate how advanced imaging could facilitate the understanding of physiology and pathophysiology. Functional imaging promises to facilitate the formulation of realistic computational models of lung growth that integrate mechano-sensitive events over multiple spatial and temporal scales to accurately describe in vivo physiology and pathophysiology. Improved computational models in turn could enhance our ability to predict regional as well as global responses to experimental and therapeutic interventions.

Pulmonary function in children with idiopathic scoliosis

Idiopathic scoliosis, a common disorder of lateral displacement and rotation of vertebral bodies during periods of rapid somatic growth, has many effects on respiratory function. Scoliosis results in a restrictive lung disease with a multifactorial decrease in lung volumes, displaces the intrathoracic organs, impedes on the movement of ribs and affects the mechanics of the respiratory muscles. Scoliosis decreases the chest wall as well as the lung compliance and results in increased work of breathing at rest, during exercise and sleep. Pulmonary hypertension and respiratory failure may develop in severe disease. In this review the epidemiological and anatomical aspects of idiopathic scoliosis are noted, the pathophysiology and effects of idiopathic scoliosis on respiratory function are described, the pulmonary function testing including lung volumes, respiratory flow rates and airway resistance, chest wall movements, regional ventilation and perfusion, blood gases, response to exercise and sleep studies are presented. Preoperative pulmonary function testing required, as well as the effects of various surgical approaches on respiratory function are also discussed.

Fusionless procedures for the management of early-onset spine deformities in 2011: what do we know?

While attempts to understand them better and treat them more effectively, early-onset deformities have gained great pace in the past few years. Large patient series with long follow-ups that would provide high levels of evidence are still almost non-existent. That there is no safe treatment algorithm defined and agreed upon for this patient population continues to pose a challenge for pediatric spine surgeons. In this review, authors who are well known for their research and experience in the treatment of early-onset scoliosis (EOS) have come together in order to answer those questions which are most frequently asked by other surgeons. The most basic eight questions in this field have been answered succinctly by these authors and a current overview is provided.

Early definitive spinal fusion in young children: what we have learned

BACKGROUND

Early-onset scoliosis, when left untreated, leads to severe deformity. Until the last decade, treatment of progressive curves in young children often consisted of definitive spinal fusion. The recognition of thoracic insufficiency syndrome associated with definitive early fusion has led to the development of new surgical techniques developed to preserve spinal and thoracic growth in young patients with progressive scoliosis.

QUESTIONS/PURPOSES

We asked: (1) Does early definitive fusion arrest progression of spinal deformity? To what extent does early definitive spinal fusion influence (2) pulmonary function and (3) thoracic growth?

METHODS

A Medline search of the published literature on early-onset scoliosis, congenital scoliosis, and infantile scoliosis between 2008 and 2010 was performed on spinal fusion for early-onset scoliosis, focusing on studies reporting pulmonary function at followup.

RESULTS

Spinal deformity is apparently not well controlled by early fusion since revision surgery has been required in 24% to 39% of patients who underwent presumed definitive fusion in early childhood. Restrictive pulmonary disease, defined as forced vital capacity less than 50% of normal, occurs in 43% to 64% of patients who undergo early fusion surgery with those children who have extensive thoracic fusions and whose fusions involve the proximal thoracic spine at highest risk. Thoracic growth after early surgery is an average of 50% of that seen in children with scoliosis who do not have early surgery. Diminished thoracic spinal height correlates with decreased forced vital capacity.

CONCLUSIONS

The literature does not support routine definitive fusion of thoracic spinal deformity at an early age in children with scoliosis.

Structure-respiration function relationships before and after surgical treatment of early-onset scoliosis

BACKGROUND

Spine and chest wall deformities in children with early onset scoliosis (EOS) frequently impair respiratory function and postnatal growth of the lung. While a relationship between deformity and such impairment has been reported in children with adolescent idiopathic scoliosis it is not well understood in children with early-onset scoliosis (EOS).

QUESTIONS/PURPOSES

We therefore describe (1) the preoperative relation between Cobb angle and forced vital capacity (FVC) in infants with EOS; (2) how changes in Cobb angle before and after surgery relate to changes in lung ventilation and perfusion in the right and left lungs.

METHODS

We measured FVC in 10 children with EOS < 3 years old using the raised volume rapid thoracic compression (RVRTC) technique and correlated them with Cobb angles. We then measured right lung contributions to total lung ventilation and perfusion using lung scans before and 4 to 57 months after placement of vertical expandable prosthetic titanium ribs (VEPTRs) in 15 children with EOS and correlated changes in right lung function with postoperative changes in Cobb angles.

RESULTS

In children 4 to 57 months of age, preoperative FVC (mean value, 83%; range, 63%-109% of predicted values) did not correlate with Cobb angles (mean value, 56º; range, 14°-120º). In children 1.8 to 11.5 years old, right lung ventilation and perfusion were abnormal in eight and seven children, respectively, but neither ventilation nor perfusion predictably normalized despite reductions in Cobb angle postoperatively.

CONCLUSIONS

The data extend the age range of children with EOS whose Cobb angles correlate poorly with FVC preoperatively. The data are also consistent with reports that reduced Cobb angles after VEPTR insertion do not correlate with postoperative changes in respiratory function.

Vertical expandable prosthetic titanium rib device insertion: does it improve pulmonary function?

PURPOSE

Vertical expandable prosthetic titanium rib (VEPTR) insertion and expansion has been advocated to increase thoracic volume and pulmonary function in patients with thoracic insufficiency syndrome. We reviewed our experience with VEPTR implantation to determine if lung function and growth is augmented, to determine the children's functional status, and if the scoliosis is controlled.

METHODS

From 2006 to 2010, 29 insertions and 57 expansions were performed in 26 patients at our institution. Demographic data were reviewed in conjunction with complications, scoliosis angles, pulmonary function tests (PFTs), and computed tomography-guided 3D reconstructions to determine lung volumes; and quality of life scores were determined using a modified Scoliosis Research Society (SRS) questionnaire preoperatively and postoperatively. The groups were also stratified by age (because of lung growth potential), disease (congenital or infantile scoliosis, Jeune syndrome, neuromuscular, other structural thoracic disorders), and sex. Analyses using SPSS (SPSS, Chicago, Ill) were performed with P < .05 considered significant.

RESULTS

Each patient underwent 3.03 ± 1.8 surgeries, spending 0.97 ± 1.8 days in the intensive care unit and 4.41 ± 6 days in the hospital for each procedure. Mean age was 90.7 ± 41 months. Of the 36 complications, most were because of infection (12), half requiring operative repair (hardware removal). The average PFT percent predicted values for forced expiratory volume in 1 second, forced vital capacity, and RV were 54.6 ± 22, 58.1 ± 24, and 145.3 ± 112, respectively, preoperatively and 51.8 ± 20, 55.9 ± 20, and 105.6 ± 31, respectively, postoperatively. The lung volumes measured by computed tomography when corrected for age do not increase significantly postoperatively. The mean Cobb measurement for the preoperative major curves was 64.7° and postoperatively was 46.1° for those curves measured preoperatively, for a 29% curve improvement. All postoperative curves had a mean of 56.4° and 58.1° at final follow-up, a 3% curve increase. The SRS scores for patients remained unchanged and no statistical difference was seen from preoperative to postoperative values. No statistically significant difference was seen in complications, PFT (forced expiratory volume in 1 second, forced vital capacity, RV), lung volumes, scoliosis angles, and SRS scores between sex, age, and disease categories.

CONCLUSION

There was mild improvement in scoliosis angles but no improvement in lung function and volume. Scoliosis Research Society scores indicate that the children have near normal function both before and after VEPTR placement. Pulmonary function, lung volume, and patient subjective assessments did not increase dramatically after VEPTR placement, although scoliosis angles improved.

Preoperative medical and surgical planning for early onset scoliosis

STUDY DESIGN

A review of current medical and surgical preoperative planning knowledge and protocols for children with early-onset scoliosis (EOS; onset less than 5 years of age).

OBJECTIVE

To describe the preoperative planning process to undertake safe and effective treatment for the EOS patient.

SUMMARY OF BACKGROUND DATA

Children with EOS present with a myriad of medical and orthopedic conditions associated with their specific diagnosis, and frequently require intensive preoperative evaluation and nutritional, pulmonary, and other support to prepare them for safe and effective treatment of the spinal/chest wall deformity. Such patients are among the most difficult and complex to treat effectively.

METHODS

A literature review of known conditions associated with EOS, and a summary of current surgical techniques to maintain deformity control while promoting spine and thoracic growth, was undertaken. Current recommendations for preoperative support and postoperative management of these complex patients are summarized, drawn from the experiences of the author and members of study groups focusing on EOS.

RESULTS

Preoperative assessment of respiratory function, potential for respiratory failure, and determination of objective criteria to indicate surgical management (deformity progression, lack of growth of spine and/or thoracic volume, lack of weight gain) are weighed against the potential for development of thoracic insufficiency syndrome. Magnetic resonance imaging evaluation for neuraxis abnormalities is considered on the basis of diagnosis. Nutritional status, osteopenia, and airway management are evaluated to minimize postoperative complications. Current general recommendations for implants and constructs for specific deformities are reviewed.

CONCLUSION

Thorough preoperative evaluation of EOS patients provides the surgeon with the knowledge to produce a sound surgical plan for this difficult and complex to treat patient population.

Current concepts in the management of early-onset idiopathic scoliosis

Early-onset scoliosis is a diagnosis when a child is presenting with scoliosis before the age of 5 years. This excludes other causes of scoliosis (e.g., congenital, neuromuscular or syndromic). Twin studies and observations of familial aggregation reveal significant genetic contributions to idiopathic scoliosis. Radiographic criteria help in distinguishing the progressive curves from those that will resolve spontaneously. One must do a complete clinical evaluation to exclude other organ involvement especially congenital heart disease, inguinal hernia and hip dysplasia. MRI scans of the neural axis are mandatory in curves greater than 20° at presentation to rule out any occult lesions in the CNS. Minor nonprogressive curves can be managed with observation until growth is completed. Some curves may be managed with casting and bracing. There is increased risk of morbidity and mortality due to respiratory failure in untreated children with early-onset scoliosis who have progressive curves. Therefore, progressive curves must be addressed surgically. Surgical procedures continue to evolve and are primarily directed at correcting and maintaining the curve correction while simultaneously preserving spinal and trunk growth. A definitive spinal fusion is indicated once the thoracic spinal growth is nearing completion.

The treatment of vertebral and chest wall deformities with expandable thoracoplasty and a prosthetic expandable implant

BACKGROUND

Expansion thoracoplasty is a temporary solution to allow complete pulomonary development in the setting of vertebral and rib cage deformities. After thoracoplasty, an expandable implant is needed to maintain the correction. The Growing Spine Profiler (GSP) is a new type of readjustable rib distracter. The purpose of this study was to evaluate the experiences of surgeons in Europe with the implantation of the GSP.

METHODS

We retrospectively reviewed 44 patients that underwent placement of the GSP at 15 sites throughout Europe. The mean age at the time of surgery was 6.24 years. Basic demographic data and postoperative management were reviewed. All patients received an opening-wedge thoracostomy with device implantation and expansion thoracoplasty. Retrospectively, the original indications for implantation were determined. Digital images of the radiographs were used to measure coronal and sagittal parameters.

RESULTS

The most common diagnoses for implantation were hemivertebrae (9), hemivertebrae with chest wall deformity (10), and unilateral bar (8). Outcomes were available for 43 patients with a mean follow-up period of 3.07 years. There were 23 patients that had an adverse event. Rib fractures were the most common adverse event, with 8 incidents in 7 patients. Radiographically, coronal curve magnitudes were maintained, whereas sagittal kyphosis gradually increased.

CONCLUSIONS

The GSP was effective in the maintenance of deformity, while providing a moderate complication rate. Further studies need to be performed to determine the safety and efficacy of this implant.