Evidence basis for management of spine and chest wall deformities in children

Growth friendly surgeries increase 3D true spine length at two-years post-operative

PURPOSE

Traditional coronal-plane vertical spine height measurements, such as T1-T12 and T1-S1 spine height, are influenced by 3-dimensional spinal deformity. Therefore, they are unreliable indicators of true spine growth. The novel 3D true spine length (3D-TSL) technique assesses spine growth regardless of the presence of 3D spinal deformity. This study evaluates the effect of growth friendly surgery on spine growth using the 3D-TSL technique at two years follow-up.

METHODS

Radiographs of early onset scoliosis (EOS) participants undergoing growth friendly surgery at a single institution were evaluated at pre-index, post-index, and at 2-year follow-up. Scoliosis, kyphosis, traditional coronal height and 3D-TSL were measured.

RESULTS

Twenty-four EOS patients (14 female) with a mean age of 6.3 years were included. Scoliosis improved from 77.8 ± 18.7° pre-index to 56.0 ± 17.8° post-index (p < 0.001); but increased at 2 years to 65.9 ± 20.1° (p < 0.05). Kyphosis improved from 56.0 ± 20.7° pre-index to 39.3 ± 13.8° post-index (p < 0.001); and increased again at 2 years to 48.6 ± 16.4° (p < 0.05). Traditional T1-S1 height increased from pre-index to post-index, to 2-year follow-up (245.5 ± 37.2 mm to 275.8 ± 42.7 mm; p < 0.001, to 288.0 ± 41.7 mm; p = 0.005). As expected, T1-S1 3D-TSL did not change from pre to immediately post-index (305.6 ± 43.9 mm vs 306.5 ± 44.0 mm); there was a significant change from post-index to 2-year follow-up (334.1 ± 48.0 mm; p < 0.001).

CONCLUSIONS

Out of plane changes in scoliosis and kyphosis over time justify the use of the 3D-TSL for this cohort of patients. There was no significant change in 3D-TSL from pre-index to post-operatively; however, during the growth phase of treatment 3D-TSL increased significantly by 27.6 mm.

Contraindications to magnetically controlled growing rods: consensus among experts in treating early onset scoliosis

PURPOSE

The purpose of this study was to describe contraindications to the magnetically controlled growing rod (MCGR) in patients with early onset scoliosis (EOS) by establishing consensus amongst expert surgeons who treat these patients frequently.

METHODS

Nine pediatric spine surgeons from an international EOS study group participated in semi-structured interviews via email to identify factors that influence decision making in the use of MCGR. A 39-question survey was then developed to specify these factors as contraindications for MCGR-these included patient age and size, etiology, medical comorbidities, coronal and sagittal curve profiles, and skin and soft tissue characteristics. Pediatric spine surgeons from the EOS international study group were invited to complete the survey. A second 29-item survey was created to determine details and clarify results from the first survey. Responses were analyzed for consensus (> 70%), near consensus (60-69%), and no consensus/variability (< 60%) for MCGR contraindication.

RESULTS

56 surgeons of 173 invited (32%) completed the first survey, and 64 (37%) completed the second survey. Responders had a mean of over 15 years in practice (range 1-45) with over 6 years of experience with using MCGR (range 2-12). 71.4% of respondents agreed that patient size characteristics should be considered as contraindications, including BMI (81.3%) and spinal height (84.4%), although a specific BMI range or a specific minimum spinal height were not agreed upon. Among surgeons who agreed that skin and soft tissue problems were contraindications (78.6%), insufficient soft tissue (98%) and skin (89%) to cover MCGR were specified. Among surgeons who reported curve stiffness as a contraindication (85.9%), there was agreement that this curve stiffness should be defined by clinical evaluation (78.2%) and by traction films (72.3%). Among surgeons who reported sagittal curve characteristics as contraindications, hyperkyphosis (95.3%) and sagittal curve apex above T3 (70%) were specified. Surgeons who indicated the need for repetitive MRI as a contraindication (79.7%) agreed that image quality (72.9%) and not patient safety (13.6%) was the concern. In the entire cohort, consensus was not achieved on the following factors: patient age (57.4%), medical comorbidities (46.4%), etiology (53.6%), and coronal curve characteristics (58.9%).

CONCLUSION

Surgeon consensus suggests that MCGR should be avoided in patients who have insufficient spinal height to accommodate the MCGR, have potential skin and soft tissue inadequacy, have too stiff a spinal curve, have too much kyphosis, and require repetitive MRI, particularly of the spine. Future data-driven studies using this framework are warranted to generate more specific criteria (e.g. specific degrees of kyphosis) to facilitate clinical decision making for EOS patients.

LEVEL OF EVIDENCE

Level V-expert opinion.

Thoracic Morphology and Bronchial Narrowing Are Related to Pulmonary Function in Adolescent Idiopathic Scoliosis

BACKGROUND

In adolescent idiopathic scoliosis (AIS), lung function impairment is not necessarily related to the coronal spinal deformity. Recently, right-sided bronchial narrowing has been reported in thoracic AIS. The aim of this study was to describe the relation of chest and spinal deformity parameters, bronchial narrowing, and lung volumes with pulmonary function in preoperative AIS.

METHODS

Spinal radiographs, low-dose computed tomographic (CT) scans of the spine including the chest, and pulmonary function tests were retrospectively collected for 85 preoperative patients with thoracic AIS in 2 centers and were compared with 14 matched controls. Three-dimensional lung and airway reconstructions were acquired. Correlation analysis was performed in which radiographic spinal parameters, CT-based thoracic deformity parameters (rib-hump index [RHi], spinal penetration index, endothoracic hump ratio, hemithoracic-width ratio), lung volume asymmetry, and bronchial cross-sectional area were compared with percent-of-predicted spirometry results.

RESULTS

Forty-one patients (48%) had a percent-of-predicted forced expiratory volume in 1 second (FEV1%) or percent-of-predicted forced vital capacity (FVC%) of <65%, and 17 patients (20%) had obstructive lung disease. All thoracic deformity parameters correlated significantly with FEV1% and FVC%; RHi was found to be the best correlate (rs = -0.52 for FEV1% and -0.54 for FVC%). Patients with AIS with impaired pulmonary function had hypokyphosis, a larger rib hump, increased spinal and thoracic rotation, a narrower right hemithorax, and increased intrusion of the spine into the chest. Spinal intrusion correlated with right-sided bronchial narrowing, relative right lung volume loss, and decreased FEV1% and FVC%. Multivariate regression including spinal and thoracic deformity parameters, lung volume asymmetry, and airway parameters could explain 57% of the variance in FEV1% and 54% of the variance in FVC%.

CONCLUSIONS

Chest intrusion by the endothoracic hump is related to right-sided bronchial narrowing and lung function loss in preoperative AIS. The findings support the theory that ventilatory dysfunction in thoracic AIS is not only restrictive but frequently has an obstructive component, especially in patients with hypokyphosis. RHi is the most predictive chest parameter for lung function loss.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Altered Bone Status in Rett Syndrome

Rett syndrome (RTT) is a monogenic neurodevelopmental disorder primarily caused by mutations in X-linked MECP2 gene, encoding for methyl-CpG binding protein 2 (MeCP2), a multifaceted modulator of gene expression and chromatin organization. Based on the type of mutation, RTT patients exhibit a broad spectrum of clinical phenotypes with various degrees of severity. In addition, as a complex multisystem disease, RTT shows several clinical manifestations ranging from neurological to non-neurological symptoms. The most common non-neurological comorbidities include, among others, orthopedic complications, mainly scoliosis but also early osteopenia/osteoporosis and a high frequency of fractures. A characteristic low bone mineral density dependent on a slow rate of bone formation due to dysfunctional osteoblast activity rather than an increase in bone resorption is at the root of these complications. Evidence from human and animal studies supports the idea that MECP2 mutation could be associated with altered epigenetic regulation of bone-related factors and signaling pathways, including SFRP4/WNT/β-catenin axis and RANKL/RANK/OPG system. More research is needed to better understand the role of MeCP2 in bone homeostasis. Indeed, uncovering the molecular mechanisms underlying RTT bone problems could reveal new potential pharmacological targets for the treatment of these complications that adversely affect the quality of life of RTT patients for whom the only therapeutic approaches currently available include bisphosphonates, dietary supplements, and physical activity.

The first magnetically controlled growing rod (MCGR) in the world - lessons learned and how the identified complications helped to develop the implant in the past decade: case report

Background

The first magnetically controlled growing rod (MCGR) was implanted in 2009. Since then multiple complications have been identified that have helped drive the development of the MCGR and its surgery. The aim of this report is to illustrate how identified complications in the first MCGR helped with developments in the past decade and to report a unique failure mechanism with stud fracture close to the barrel opening.

Case presentation

A 5-year old girl with a scoliosis of 58.5 degrees at T1–9 and 72.8 degrees at T9-L4 had a single MCGR inserted and anchored at T3–4 and L3–4. At postoperative 13 months the MCGR was noted to have lost of distraction between lengthening episodes due to unrestricted turning of the internal magnet. To prevent further loss of distraction, an external magnet was placed outside the skin to prevent the magnet from turning back. The overall balance was suboptimal and after the rod was fully distracted, proximal junctional kyphosis occurred. Subsequently, the MCGR was modified with an internal keeper plate to prevent loss of distraction and a dual set of these rods were implanted when the patient was 9 years old. Extension proximally to C7-T1 was done to manage the proximal junctional kyphosis. Her spinal balance improved and distractions continued. She subsequently developed add-on below and the piston rod was not aligned with the actuator. The lumbar spine was also observed to have autofusion. She subsequently had final fusion surgery performed at the age of 15 from C7-L4 leaving a residual tilt below to avoid fusion to the pelvis. The final extracted rod on the left side indicated the “crooked rod sign” on X-ray and rod dissections revealed a new failure mechanism of stud fracture close to the barrel opening. Body fluids and tissue may infiltrate the rod despite no obvious deformation or fractures resulting in hastened wearing of the threads.

Conclusions

There are various complications associated with MCGRs that are related to rod design and surgical inexperience. Repeated rod stalling is not recommended with potential stud fracture and “crooked rod sign”. Rotor stalling and thread wearing which indicates rod failure still require solutions.

Burden of care in families of patients with early onset scoliosis

Early onset scoliosis is a complex manifestation of a heterogenous group of disorders, often necessitating multiple medical and surgical interventions to address the spinal deformity and its accompanying comorbidities. Current literature documents decreases in the health-related quality of life of these patients; however, there is a distinct lack of published data examining the burden on their caregivers. The purpose of this study is to compare burden on caregivers of children with early onset scoliosis and those on caregivers of age-matched healthy peers. A multicenter retrospective cohort study was conducted by querying a national registry for patients with early onset scoliosis diagnosed before 10 years old whose caregivers completed the caregiver burden (CB) and financial burden (FB) domains of the Early Onset Scoliosis Questionnaire (EOSQ-24) before their treatment. Scores were compared by etiology and planned treatment. The study identified 503 patients categorized by etiology and eventual treatment type. Overall, FB and CB scores for patients with early onset scoliosis were ≥10% worse than those of their age-matched peers, greater than the minimal clinically important difference for the EOSQ-24 (P < 0.001). Non-idiopathic patients' scores were ≥16% worse than age-matched peers regardless of future treatment (P < 0.001), while scores for idiopathic patients were varied. Idiopathic patients who went on to be observed had similar scores to national norms, but those who were managed either non-operatively (14% worse FB, 7% worse CB; P < 0.001) or operatively (25% worse FB, 27% worse CB; P > 0.05) had caregivers who reported greater burdens compared to those of healthy peers. This study suggests burdens on caregivers of patients with early onset scoliosis of nearly all etiologies are greater than those imposed on caregivers of healthy children, even before the additional stress of treatment is imposed. Level of evidence: II.

Systematic investigation of metallosis associated with magnetically controlled growing rod implantation for early-onset scoliosis

AIMS

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

METHODS

This was a prospective observational study of patients with early onset scoliosis (EOS) treated with MCGRs and undergoing rod exchange who were consecutively recruited between February 2019 and January 2020. Ten patients were recruited (mean age 12 years (SD 1.3); 2 M:8 F). The configurations of the MCGR were studied to reveal the distraction mechanisms, with crucial rod parts being the distractable piston rod and the magnetically driven rotor inside the barrel of the MCGR. Metal-on-metal contact in the form of ring-like wear marks on the piston was found on the distracted portion of the piston immediately outside the barrel opening (BO) through which the piston rod distracts. Biopsies of paraspinal muscles and control tissue samples were taken over and away from the wear marks, respectively. Spectral analyses of the rod alloy and biopsies were performed to reveal the metal constituents and concentrations. Histological analyses of the biopsies were performed with haematoxylin and eosin staining.

RESULTS

Titanium (Ti), vanadium (V), and neodymium (Nd) concentrations in the biopsies taken near the wear marks were found to be significantly higher than those in the control tissue samples. Significantly increased Nd concentrations were also found in the tissues near the barrel of the MCGR. Chronic inflammation was revealed by the histological studies with fibrosis and macrophage infiltration. Black particles were present within the macrophages in the fibrotic tissues.

CONCLUSION

Ti and V were generated mainly at the BO due to metal-on-metal contact, whereas the Nd from the rotor of the MCGR is likely released from the BO during distraction sessions. Phagocytotic immune cells with black particles inside raise concern regarding the long-term implications of metallosis. Cite this article: Bone Joint J 2020;102-B(10):1375-1383.

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.

Current status of the magnetically controlled growing rod in treatment of early-onset scoliosis: What we know after a decade of experience

The magnetically controlled growing rod (MCGR) has had approximately 10 years of clinical experience worldwide. Clinical effectiveness to control early-onset scoliosis is consistent even at final surgery. MCGRs have significantly lower relative percentage of infection or wound complications as compared to traditional growing rods. Most common complications include foundation failure and failure of distraction. Contouring of the rod especially at the proximal segment while accommodating for the straight actuator remains a difficult task and its failure may lead to proximal junctional kyphosis. Unique complications of MCGR include clunking, temporary diminishing distraction gains, and metallosis. Temporary reductions in distraction gains are observed as the MCGR lengthens but return to normal baseline distraction gains after rod exchange. Lack of standardization for rod configuration, distraction strategies and decisions of whether to keep the rods in situ, remove without fusion surgery or to perform spinal fusion at skeletal maturity will require further study.

Expert Consensus for Early Onset Scoliosis Surgery

BACKGROUND

Despite a validated classification system, high-quality multicenter research databases (CSSG/GSSG), and a recent proliferation in publications, early-onset scoliosis (EOS) surgeons have no consensus on standards for surgical treatment. The 21st-century revolution in EOS care has only accelerated, with the arrival of a classification system, magnetically controlled growing rod, nusinersen, and improved nonoperative care (Mehta or Risser casting and compliance-monitored braces). This dizzying pace of change may have outstripped our ability to develop best-practice standards for EOS surgical indications. To learn where consensus is best (and worst) at this moment, we surveyed EOS world thought-leaders on a collection of representative cases.

METHODS

A 6-case survey was constructed and sent to 20 EOS world thought-leaders. The cases were selected to be representative of the major treatment categories: idiopathic, neuromuscular, syndromic, congenital, thoracic dysplasia, and spinal muscular atrophy (specifically to assess the impact of nusinersen and parasol deformity on surgical planning). Respondents were queried regarding treatment with specific attention to instrumentation and construct when surgery was selected. Responses regarding surgical timing and technique were analyzed for consensus (defined as >80%). χ analysis was performed to evaluate for differences in treatment preferences based on years of experience.

RESULTS

The survey response was 100%. Clinical experience ranged from 8 to 40 years (average 23.9 y). There was no consensus on any case. The greatest variability was on the congenital case; the closest to consensus was on the spinal muscular atrophy case. Three or more approaches were selected for all 6 cases; >4 approaches were selected for 5 cases. There is a trend towards screw fixation for proximal anchors. The management of thoracic dysplasia and parasol deformity is far from consensus.

CONCLUSION

The lack of consensus for surgical treatment of 6 representative EOS cases demands a renewed effort and commitment to develop best-practice guidelines based on multicenter outcome data.

LEVEL OF EVIDENCE

Level V-Expert Opinion.

Idiopathic Early-onset Scoliosis: Growing Rods Versus Vertically Expandable Prosthetic Titanium Ribs at 5-year Follow-up

BACKGROUND

Distraction-based techniques allow spinal growth until skeletal maturity while preventing curve progression.

METHODS

Two multicenter early-onset scoliosis databases were used to identify patients with idiopathic spine abnormalities treated with traditional growing rods (TGR) or vertically expandable titanium ribs (VEPTR). Patients underwent at least 4 lengthenings and had at least 5-year follow-up. Significance was set at P<0.05.

RESULTS

In total, 50 patients treated with TGR and 22 treated with VEPTR were included. Mean (±SD) age at surgery was 5.5 (±2.0) years for the TGR group versus 4.3 (±1.9) years for the VEPTR group (P=0.044); other demographic parameters were similar. VEPTR patients had more procedures (mean 15±4.2) than TGR patients (mean 10±4.0) (P=0.001). Unilateral constructs were present in 18% (4 of 22) of VEPTR and 16% (8 of 50) of TGR patients. Bilateral constructs spanned a mean 2.1 additional surgical levels and exposed patients to 1.6 fewer procedures than unilateral constructs. Curve correction was similar between bilateral and unilateral constructs. TGR patients experienced greater curve correction (50%) than VEPTR patients (27%) (P<0.001) and achieved a greater percentage of thoracic height gain (24%) than VEPTR patients (12%) (P=0.024). At latest follow-up, TGR patients had better maintenance of curve correction, less kyphosis, and 15% greater absolute gain in thoracic height versus VEPTR patients. TGR patients had a lower rate of wound complications (14%) than VEPTR patients (41%) (P=0.011).

CONCLUSIONS

In patients with idiopathic early-onset scoliosis, TGRs produced greater initial curve correction, greater thoracic height gains, less kyphosis, and lower incidence of wound complications compared with VEPTR.

LEVEL OF EVIDENCE

Level III.

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.

Respiratory Complications After Posterior Spinal Fusion for Neuromuscular Scoliosis: Children With Rett Syndrome at Greater Risk Than Those With Cerebral Palsy

STUDY DESIGN

Retrospective cohort.

OBJECTIVE

To determine how respiratory failure rates and duration of intensive care unit (ICU) stay after posterior spinal fusion (PSF) for neuromuscular scoliosis compare between children with Rett syndrome (RS) versus cerebral palsy (CP).

SUMMARY OF BACKGROUND DATA

Rett syndrome and CP are associated with high incidence of neuromuscular scoliosis and respiratory dysfunction.

METHODS

We included 21 patients with RS (mean age, 13 ± 3.1 yrs) and 124 with CP (mean age, 14 ± 3.2 yrs) who underwent PSF by one surgeon from 2004 to 2017. Preoperative motor function was assessed using the Gross Motor Function Classification System (GMFCS). Primary outcomes were respiratory failure and duration of ICU stay. Secondary outcomes were pneumonia and prolonged use of positive pressure ventilation (PPV). Using multivariate regression, we identified associations of age, intraoperative vital signs, duration of hospital stay, number of vertebral levels fused, anesthesia and surgery durations, and estimated blood loss with longer ICU stay and respiratory failure.

RESULTS

A greater proportion of CP patients (96%) than RS patients (66%) were in GMFCS IV or V (P < 0.01). Respiratory failure was more common in RS patients (43% vs. 19%; P = 0.02), as was PPV (67% vs. 31%; P < 0.01). RS patients had shorter median durations of anesthesia and surgery (P < 0.01). RS patients had a longer median (interquartile range) ICU stay (4 days [1-5] vs. 2 days [2-19]; P = 0.01). Incidence of pneumonia did not differ between groups (P = 0.69). Only RS diagnosis (P = 0.02) and prolonged PPV (P < 0.01) were associated with longer ICU stay.

CONCLUSION

Despite better preoperative motor function and shorter anesthesia and surgery durations, patients with RS experienced more respiratory failure, prolonged PPV use, and longer ICU stays after PSF than did children with CP.

LEVEL OF EVIDENCE

4.

Cardiopulmonary Function in Patients with Congenital Scoliosis: An Observational Study

BACKGROUND

Patients with congenital scoliosis often have restrictive pulmonary dysfunction on static pulmonary function testing (PFT). Although frequently asymptomatic during daily activities, these patients are generally assumed to have reduced exercise capacity. The aim of this study was to use dynamic cardiopulmonary exercise testing (CPET) to investigate exercise capacity and its association with spinal deformity in patients with congenital scoliosis.

METHODS

Sixty patients with congenital scoliosis who underwent preoperative spinal radiography, PFT, and CPET were included from January 2014 to November 2017. The impact of thoracic spinal deformity and rib anomalies on pulmonary function and physical capacity was investigated.

RESULTS

A significant deterioration in pulmonary function with increases in the severity of the major thoracic curve was demonstrated by the forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), and total lung capacity (all p < 0.001). The ratio of FEV1 to FVC was similar regardless of thoracic curve severity. A smaller tidal volume during exercise testing reflected restrictive dysfunction in the patients with the most severe curves. CPET also revealed a significant trend of faster breathing by patients with a severe thoracic curve (p < 0.001). Exercise capacity indicators such as work rate (p = 0.019), heart rate (p = 0.015), and oxygen saturation (p = 0.006) were significantly reduced only in patients with a thoracic curve of >100°. Pulmonary dysfunction was the major contributor to exercise intolerance. Compared with mild pulmonary dysfunction, moderate and severe dysfunction was associated with an abnormal breathing pattern and lower work rate (p = 0.032) and peak oxygen intake (p = 0.042), indicating worse exercise tolerance.

CONCLUSIONS

Congenital scoliosis leads to restrictive pulmonary dysfunction, which reduces the tidal volume and forces patients to accelerate respiratory rates during exercise. Patients with a thoracic curve of >100° are unable to compensate and have significantly reduced exercise capacity.

LEVEL OF EVIDENCE

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

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.

Preliminary Results of Magnetically Controlled Growing Rods for Early Onset Scoliosis

BACKGROUND

Growth-sparing techniques for the treatment of early onset scoliosis (EOS) have developed significantly over the last years. Traditional growing rods (GRs) require repeated surgical lengthening under anesthesia. Since June 2011 we have been using the magnetically controlled growing rods (MCGR) to treat patients with progressive EOS.

METHODS

Thirty-five patients with EOS of different etiologies underwent treatment with MCGR. We record about our preliminary results of 24 patients who fulfilled the inclusion criteria of a minimum follow-up (FU) of 12 month and >3 lengthenings. The mean age at surgery was 8.9±2.5 years. Correction of the primary curve after the index surgery and after lengthenings was measured on standing radiographs using the Cobb technique. T1-T12 and T1-S1 spinal length were also measured. Intraoperative and postoperative complications were recorded.

RESULTS

The mean FU was 21.1±7.3 months. All patients had a minimum of 3 outpatient lengthenings [mean, 4.6±1.5 (range, 3 to 8)]. The mean primary curve was 63±15 degrees (range, 40 to 96 degrees) and improved to 29±11 degrees (range, 11 to 53 degrees; P<0.001) after MCGR. The mean major curve after most recent lengthening was 26 degrees (range, 8 to 60 degrees; P<0.07). The T1-T12 as well as the T1-S1 length increased significantly (P<0.001). The mean preoperative thoracic kyphosis decreased from 43±24 degrees (range, -32 to 86 degrees) to 27±12 degrees (range, 9 to 50 degrees; P<0.001) after surgery, respectively, and measured 32±12 degrees (range, 12 to 64 degrees; P<0.05) at last FU. In 1 patient a loss of distraction occurred making rod exchange necessary. Three patients developed a proximal junctional kyphosis and in another patient a screw pull out occurred that required revision surgery.

CONCLUSIONS

Our results demonstrate that MCGR is a safe and effective nonfusion technique in the treatment of progressive EOS avoiding repeated surgical lengthening procedures. It provides adequate distraction similar to standard GR. The magnetically induced transcutaneous lengthening allows noninvasive distraction achieving spinal growth comparable to conventional GR techniques.

LEVEL OF EVIDENCE

Level IV-retrospective nonrandomized objective study.

Learning Curve in Monitoring Magnetically Controlled Growing Rod Distractions With Ultrasound

STUDY DESIGN

Prospective study.

OBJECTIVE

To determine whether a learning curve exists for ultrasound measurement of magnetically controlled growing rod (MCGR) distractions.

SUMMARY OF BACKGROUND DATA

For patients managed by MCGRs, close monitoring of interval distraction length gains is important to determine whether the distractions are translating into actual spine growth. Radiographs are the criterion standard for measuring length gains, but ultrasound has been shown to be effective in monitoring distraction lengths without radiation exposure. It is, however, an operator-dependent tool and thus the accuracy of ultrasound measurement of distracted length may improve with experience.

METHODS

This is a prospective correlation analysis of patients who underwent MCGR treatment for scoliosis. The study period was inclusive of 19th February 2013 to 31st March 2015. All subjects were consecutively recruited in a prospective manner. Data regarding date of the distraction visit, and the interval radiograph and ultrasound measurements of the distracted lengths were collected. Only those episodes with both radiograph and ultrasound performed were used for analysis. The mean differences in change of radiograph and ultrasound measurements were plotted to determine correlation differences and to observe for a learning curve.

RESULTS

A total of 379 distraction episodes were analyzed. The mean differences between ultrasound and radiograph measurements per distraction episode were -0.3 mm for the right rod and -0.1 mm for the left rod. For learning curve analysis, there were three distinct timepoints in which the difference of correlation became significantly better and were described as clusters. The correlation in the first cluster (19th February 2013 to 15th October 2013) was 0.612 (right rod) and 0.795 (left rod), the second cluster (16th October 2013 to 20th May 2014) was 0.879 (right rod) and 0.918 (left rod), and the third cluster (21st May 2014 to 31st March 2015) was 0.956 (right rod) and 0.932 (left rod). Thus, a plateau was observed at the second cluster, which translated to 97 to 146 rod measurements.

CONCLUSION

Correlation between radiograph and ultrasound measurements is reasonable to begin with but improves with time. During initial use, successful distractions should correlate between the clinical feel and ultrasound confirmation. Although the absolute value may not be accurate and may require radiographs to confirm, with time and experience, ultrasound measurements can then be more reliable.

LEVEL OF EVIDENCE

3.

Clinical and biological progress over 50 years in Rett syndrome

In the 50 years since Andreas Rett first described the syndrome that came to bear his name, and is now known to be caused by a mutation in the methyl-CpG-binding protein 2 (MECP2) gene, a compelling blend of astute clinical observations and clinical and laboratory research has substantially enhanced our understanding of this rare disorder. Here, we document the contributions of the early pioneers in Rett syndrome (RTT) research, and describe the evolution of knowledge in terms of diagnostic criteria, clinical variation, and the interplay with other Rett-related disorders. We provide a synthesis of what is known about the neurobiology of MeCP2, considering the lessons learned from both cell and animal models, and how they might inform future clinical trials. With a focus on the core criteria, we examine the relationships between genotype and clinical severity. We review current knowledge about the many comorbidities that occur in RTT, and how genotype may modify their presentation. We also acknowledge the important drivers that are accelerating this research programme, including the roles of research infrastructure, international collaboration and advocacy groups. Finally, we highlight the major milestones since 1966, and what they mean for the day-to-day lives of individuals with RTT and their families.

Frequent small distractions with a magnetically controlled growing rod for early-onset scoliosis and avoidance of the law of diminishing returns

PURPOSE

To assess the effect of frequent small distractions with a magnetically controlled growing rod (MCGR) on spinal length gain and achieved distraction length in children with early-onset scoliosis (EOS), and to determine whether the law of diminishing returns applies to this group of patients with MCGR.

METHODS

A consecutive series of 3 males and 4 females with EOS who underwent MCGR implantation at a mean age of 10.2 years and were followed up for a mean of 3.8 years were reviewed. Distraction was aimed at 2 mm monthly. The coronal Cobb angle, T1-S1 length gain, and achieved distraction length were measured at 6-monthly intervals.

RESULTS

The mean total number of distractions was 31. Four of the patients had problems that may have affected distractions. The mean coronal Cobb angle improved post-operatively and was maintained throughout the follow-up period. The mean T1-S1 length gain and achieved distraction length varied over the follow-up period and did not diminish with repeated lengthening.

CONCLUSIONS

Frequent small distractions with the MCGR for EOS enable T1-S1 and achieved distraction length gain without significant reduction in gain after repeated lengthening.

Family satisfaction following spinal fusion in Rett syndrome

PURPOSE

We evaluated family satisfaction following spinal fusion in girls with Rett syndrome.

METHODS

Families participating in the population-based and longitudinal Australian Rett Syndrome Database whose daughter had undergone spinal fusion provided data on satisfaction overall, care processes and expected changes in health and function. Content analysis of responses to open-ended questions was conducted.

RESULTS

Families reported high levels of overall satisfaction and consistently high ratings in relation to surgical and ICU care. Outstanding clinical care and the development of strong partnerships with clinical staff were much appreciated by families, whereas poor information exchange and inconsistent care caused concerns.

CONCLUSIONS

Family satisfaction is an important outcome within a patient-centred quality of care framework. Our findings suggest strategies to inform the delivery of care in relation to spinal fusion for Rett syndrome and could also inform the hospital care of other children with disability and a high risk of hospitalization.

Surgical fusion of early onset severe scoliosis increases survival in Rett syndrome: a cohort study

AIM

Scoliosis is a common comorbidity in Rett syndrome and spinal fusion may be recommended if severe. We investigated the impact of spinal fusion on survival and risk of severe lower respiratory tract infection in Rett syndrome.

METHOD

Data were ascertained from hospital medical records, the Australian Rett Syndrome Database, a longitudinal and population-based registry, and from the Australian Institute of Health and Welfare National Death Index database. Cox regression and generalized estimating equation models were used to estimate the effects of spinal surgery on survival and severe respiratory infection respectively in 140 females who developed severe scoliosis (Cobb angle ≥45°) before adulthood.

RESULTS

After adjusting for mutation type and age of scoliosis onset, the rate of death was lower in the surgery group (hazard ratio [HR] 0.30, 95% confidence interval [CI] 0.12-0.74; p=0.009) compared to those without surgery. Rate of death was particularly reduced for those with early onset scoliosis (HR 0.17, 95% CI 0.06-0.52; p=0.002). There was some evidence to suggest that spinal fusion was associated with a reduction in risk of severe respiratory infection among those with early onset scoliosis (risk ratio 0.41, 95% CI 0.16-1.03; p=0.06).

INTERPRETATION

With appropriate cautions, spinal fusion confers an advantage to life expectancy in Rett syndrome.

Actuator pin fracture in magnetically controlled growing rods: two cases

BACKGROUND CONTEXT

Magnetically controlled growing rods (MCGRs) are used in the management of early-onset scoliosis (EOS). Each MCGR contains a telescopic actuator that serves as the distraction element when stimulated by an external remote controller (ERC), permitting non-invasive lengthening in the outpatient clinic.

PURPOSE

This report highlights a subtle cause of MCGR failure. We present the first two reported cases of lengthening pin fracture in patients with dual-MCGR constructs.

STUDY DESIGN

We present two cases of patients with EOS treated with dual-construct MAGEC (MAGnetic Expansion Control, Ellipse Technologies Inc, Aliso Viejo, CA, USA) MCGRs.

METHODS

A 12-year-old boy presented describing a "popping" sensation in his thoracic spine and resultant grating 36 months following MCGR insertion.

RESULTS

A plain radiograph revealed a subtle fracture of the lengthening pin within the actuator of the right MCGR. Following identification of this case of implant failure, we reviewed the most recent radiographs of all nine of our patients treated with this MCGR in our institution, resulting in the discovery of bilateral MCGR lengthening pin fractures in an otherwise asymptomatic 11-year-old girl.

CONCLUSIONS

Clinicians should have a high index of suspicion of structural implant failure when presented with histories similar to those reported in our first case, or following unsuccessful distraction of MCGRs. In such cases new radiographs should be taken, and all previous images should be reviewed for evidence of this phenomenon. Centers that document MCGR lengthening with ultrasound should obtain plain radiographs every 6 months to evaluate the structural integrity of the implant.

Clinical utility of ultrasound to prospectively monitor distraction of magnetically controlled growing rods

BACKGROUND CONTEXT

Growing rods are commonly used for surgical treatment of skeletally immature patients with scoliosis, but require repeated surgeries for distractions and are fraught with complications. As an alternative, the use of magnetically controlled growing rods (MCGR) allows for more frequent non-invasive distractions to mimic normal growth. However, more plain radiographs are needed to monitor increased distraction frequency, thereby increasing ionizing radiation exposure to the developing child. The use of ultrasound, which emits no radiation, has been found in a cross-sectional study to be reliable in measuring MCGR distractions.

PURPOSE

The study aims to address the prospective clinical utility of ultrasound compared with plain radiographs for assessing MCGR distractions.

STUDY DESIGN

This is a prospective study.

PATIENT SAMPLE

The study includes patients with early-onset scoliosis undergoing distractions after MCGR implant.

OUTCOME MEASURES

The distraction length on plain radiographs and ultrasound was measured.

METHODS

This is a prospective study of patients treated with MCGR. Patients with both single- and dual-rod systems were included. Outpatient distractions were performed at monthly intervals, targeting 2 mm of distraction on each occasion. Assessment of distraction length was monitored by ultrasound at each visit; plain radiographs were taken every 6 months and were compared with ultrasound measurements.

RESULTS

Nine patients (5 female, 4 male), with a mean of 29 distractions (standard deviation [SD] ±14.3), were recruited. The mean distracted length per 6 months was 5.7 mm (SD ±3.6 mm) on plain radiographs and 5.2 mm (SD ±3.9 mm) on ultrasound for the concave rod, and 6.1 mm (SD ±3.6 mm) on plain radiographs and 5.9 mm (SD ±3.8 mm) on ultrasound for the convex rod. Excellent inter- and intra-rater reliabilities were observed for radiographic and ultrasound measurements. An excellent correlation was noted between the two imaging modalities (r=0.93; p<.0001).

CONCLUSIONS

This is the first prospective study to validate that ultrasound assessment of MCGR distraction lengths was highly comparable with that of plain radiographs. The present study has verified that ultrasound can be used to document length changes by distraction over time and that it had high clinical utility. Ultrasound can be a reliable alternative to plain radiographs, thereby avoiding radiation exposure and its potential detrimental sequelae in the developing child.

Special article: Update on the magnetically controlled growing rod: tips and pitfalls

Magnetically controlled growing rods (MCGR) have become an important treatment option in young patients with spinal deformities. This device allows for gradual lengthening on an outpatient setting with continuous neurological monitoring in an awake patient. With its growing popularity and interest, this study reports the tips, pitfalls, and complications of the MCGR for management of scoliosis. On 3 June 2015 at the University of Hong Kong, 32 participants from 16 regions shared their experience with MCGR. Current indications for surgery include early-onset scoliosis patients. Adolescent idiopathic scoliosis and congenital scoliosis patients have less favourable outcomes. The number of instrumented levels should be minimised, as all instrumented levels must be included in the definitive fusion surgery. Rod contouring is important and owing to the straight portion of the rod housing the magnet, there is limited proximal rod portion for proper contouring, which may predispose to proximal junctional kyphosis. There is currently no consensus on the rod configuration, timing, frequency, technique, and amount of distraction. Risk factors for distraction failure include larger patients, internal magnets too close to each other, and magnets too close to the apex of the major curve. Future studies should resolve the issues regarding the technique of distraction, optimal frequency and amount of distraction per session. More comprehensive cost analyses should be performed.

Patient-Reported Outcome Instruments in Pediatric Deformity Surgery: A Bibliometric Analysis

STUDY DESIGN

Bibliometric analysis.

OBJECTIVES

To identify patient-reported outcomes instruments (PROIs) used in pediatric deformity surgery research over the past decade and their frequency and usage trends.

SUMMARY OF BACKGROUND DATA

The emphasis on PROIs is increasing along with the demand for evidence-based medicine and cost-effectiveness research. Therefore, investigators and PROI consensus writers should be aware of the PROIs used in pediatric deformity and usage trends.

METHODS

Five top orthopedics journals were reviewed from 2004 to 2013 for clinical studies of surgical intervention in pediatric deformity that report PROIs. Publication year, level of evidence (LOE), and PROIs were reported for each article. Mean and range scores for the most frequently used PROIs were analyzed at 2-year follow-up.

RESULTS

A total of 79 studies using PROIs were published in the pediatric deformity literature over the period studied. The researchers identified 21 named PROIs and 6 additional custom questionnaires. The Scoliosis Research Society (SRS)-22 was the most frequently used instrument (32.9%), followed by the SRS-24 (29.1%), Oswestry disability index (17.7%), visual analog scale (12.7%), SRS-30 (10.1%), and Short Form-36 (6.3%). Level of evidence III was most common (39.2%) and 1 LOE I study was identified. Mean preoperative and postoperative SRS instrument scores were 4.0 (95% confidence interval, 3.8-4.1) and 4.5 (95% confidence interval, 4.4-4.6), respectively, in SRS-22r equivalents. No studies met the criteria for mean and range calculation for the other top instruments.

CONCLUSIONS

Scoliosis Research Society instruments are used in 74.7% of pediatric deformity studies reporting PROIs. Therefore, there is a consensus that SRS instruments should be used in pediatric deformity outcome studies; yet, consistent use of the most up-to-date version, the SRS-22r, is still needed. General health questionnaires are currently underused in pediatric deformity research. Version reporting and use of the latest versions of PROIs need to be improved in future studies.

Is There an Optimal Time to Distract Dual Growing Rods?

STUDY DESIGN

Retrospective multicenter observational cohort study.

OBJECTIVES

To determine whether there is a significant difference in final spinal height achieved, instrumented height, or Cobb angle related to the mean time interval between distractions of dual growing rods.

SUMMARY OF BACKGROUND DATA

Patients were prospectively enrolled in "The Treatment of Progressive Early Onset Spinal Deformities: A Multi-Center Study." Additional data were collected via a retrospective review of medical records.

METHODS

Using data from a multicenter database, the authors identified 46 patients (23 boys and 23 girls) with early-onset scoliosis who were treated with dual growing rods and who had surgical treatment spanning more than 4 years. The patients were divided into 2 groups: those who had less than 9 months (16 patients) and those who had 9 months or more (30 patients) between distractions. Standard univariate statistics were calculated. The researchers performed 2-tailed t tests. Significance was set at p = .05.

RESULTS

The differences in primary Cobb angle, T1-S1 height, and instrumented segment length at the last distraction or final arthrodesis, compared with the post-index procedure values, were not significantly different (p = .52, .58, and .60, respectively) between groups with the available data. The normalized instrumented height gains, in millimeters per year, were not significantly different (p = .22).

CONCLUSIONS

Patients with longer times between growing-rod distractions (9 or more months) had no significant differences in primary Cobb angle, T1-S1 length, or instrumented length gain compared with patients with shorter times (less than 9 months) between distractions.

Development and initial validation of the Classification of Early-Onset Scoliosis (C-EOS)

BACKGROUND

Early-onset scoliosis is a heterogeneous condition, with highly variable manifestations and natural history. No standardized classification system exists to describe and group patients, to guide optimal care, or to prognosticate outcomes within this population. A classification system for early-onset scoliosis is thus a necessary prerequisite to the timely evolution of care of these patients.

METHODS

Fifteen experienced surgeons participated in a nominal group technique designed to achieve a consensus-based classification system for early-onset scoliosis. A comprehensive list of factors important in managing early-onset scoliosis was generated using a standardized literature review, semi-structured interviews, and open forum discussion. Three group meetings and two rounds of surveying guided the selection of classification components, subgroupings, and cut-points. Initial validation of the system was conducted using an interobserver reliability assessment based on the classification of a series of thirty cases.

RESULTS

Nominal group technique was used to identify three core variables (major curve angle, etiology, and kyphosis) with high group content validity scores. Age and curve progression ranked slightly lower. Participants evaluated the cases of thirty patients with early-onset scoliosis for reliability testing. The mean kappa value for etiology (0.64) was substantial, while the mean kappa values for major curve angle (0.95) and kyphosis (0.93) indicated almost perfect agreement. The final classification consisted of a continuous age prefix, etiology (congenital or structural, neuromuscular, syndromic, and idiopathic), major curve angle (1, 2, 3, or 4), and kyphosis (-, N, or +) variables, and an optional progression modifier (P0, P1, or P2).

CONCLUSIONS

Utilizing formal consensus-building methods in a large group of surgeons experienced in treating early-onset scoliosis, a novel classification system for early-onset scoliosis was developed with all core components demonstrating substantial to excellent interobserver reliability. This classification system will serve as a foundation to guide ongoing research efforts and standardize communication in the clinical setting.

Distractional failure forces comparison of different anchor sites for the pediatric growing rod technique

PURPOSE

To analyze the distraction load-to-failure force supported by pedicle, lamina or rib linked to different constructs in pediatric cadaveric thoracic spine.

METHODS

Eighteen pediatric cadaveric thoracic spines with rib cages were randomly assigned into three testing groups: A (lamina and pedicle), B (rib and pedicle), and C (rib and lamina). Each specimen was sectioned into six units from T1-T2 to T11-T12. A longitudinal load-to-failure test simulating growing rod distraction force was performed with an ElectroForce(®)3500 machine, and yield forces were statistically analyzed.

RESULTS

The results showed that pedicle and lamina anchors could provide a similar capacity against distraction force in group A (P > 0.05), which was almost double that of ribs in groups B and C (P < 0.05). The data showed that T5 and T7 pedicles and laminas seem to provide the lowest distractional force. Furthermore, break pedicle insertion provides 75.6 % of distractional force as compared to the same segments with intact pedicle insertion.

CONCLUSIONS

Our results suggest the lamina as a proximal thoracic anchor site for pediatric spinal deformity. The pedicle and lamina of T5 and T7 vertebrae seemed to provide a lower distractional force than other thoracic segments in our test.

[Early onset scoliosis. What are the options?]

The prognosis of children with progressive early onset scoliosis has improved considerably due to recent advances in surgical and non-surgical techniques and the understanding of the importance of preserving the thoracic space. Improvements in existing techniques and development of new methods have considerably improved the management of this condition. Derotational casting can be considered in children with documented progression of a <60° curve without previous surgical treatment. Both single and dual growing rods are effective, but the latter seem to offer better results. Hybrid constructs may be a better option in children who require a low-profile proximal anchor. The vertical expandable prosthetic titanium rib (VEPTR(®)) appears to be beneficial for patients with congenital scoliosis and fused ribs, and thoracic Insufficiency Syndrome. Children with medical comorbidities who may not tolerate repeated lengthenings should be considered for Shilla or Luque Trolley technique. Growth modulation using shape memory alloy staples or other tethers seem promising for mild curves, although more research is required to define their precise indications.

Posterior vertebral column resection in early onset spinal deformities

PURPOSE

Early onset spinal deformities (EOSD) can be life-threatening in very young children. In the growing spine, surgical intervention is often unavoidable and should be carried out as soon as possible. A deformed section of the spine not only affects the development of the remaining healthy spine, but also that of the chest wall (which influences pulmonary function), the extremities and body balance. Posterior vertebral column resection (PVCR) represents an effective surgical solution to address such problems. However, reports in the literature concerning PVCR are mostly limited to its use in adolescents or adults. The purpose of this study was to illustrate our experience with PVCR in EOSD and to describe the surgical technique with respect to the unique anatomy of young children.

MATERIALS AND METHODS

Four children [mean age 3.7 (range 2.5-5.2) years] with severe spinal deformity underwent PVCR through a single approach. Multimodal intraoperative monitoring was used in all cases. Surgery included one stage posterior circumferential resection of one vertebral body along with the adjoining intervertebral discs and removal of all posterior elements. A transpedicular screw-rod system was used for correction and stabilisation. Fusion was strictly limited to the resection site, allowing for later conversion into a growing rod construct at the remaining spine, if necessary. Relevant data were extracted retrospectively from patient charts and long spine radiographs.

RESULTS

The mean operation time was 500 (range 463-541) min, with an estimated blood loss of 762 (range 600-1,050) ml. Mean follow-up time was 6.3 (range 3.5-12.4) years. After PVCR, the mean Cobb angle for scoliosis was reduced from 69° (range 50-99°) to 29° (5-44°) and the sagittal curvature (kyphosis) from 126° (87-151°) to 61° (47-75°). The mean correction of scoliosis was 57 % (18-92°) and of kyphosis, 51 % (44-62°). There were no spinal cord-related complications. In three patients, spinal instrumentation for growth guidance (fusion less growing rod technique) was applied. Two patients had complications: one patient had a complication of anesthesia, halo pin failure, and revision surgery with extension of the instrumentation cranially due to loss of correction; the second patient had a postoperative infection, which required plastic reconstructive measures.

CONCLUSION

PVCR appears to be an effective technique to treat severe EOSD. There are important differences in its use in young children when compared with older patients. In patients with EOSD, additional surgical procedures are often necessary during growth, and hence non-fusion instrumentation beyond the vertebral resection site is advantageous, as it permits spinal growth and the later addition of fusion.

More experienced surgeons less likely to fuse: a focus group review of 315 hypothetical EOS cases

INTRODUCTION

Previous work has identified significant variability in decision making and multiple areas of clinical equipoise in the treatment of early-onset scoliosis (EOS). In an attempt to better understand possible determinants of this variability, we examined the relationship between socioclinical attributes of 11 participating surgeons and decision making regarding the treatment of EOS.

METHODS

Eleven experienced EOS surgeons were surveyed. The first part of the survey consisted of questions regarding surgeon and practice demographics. Next, surgeons were queried regarding their preferred management of 315 hypothetical EOS cases. Cases varied considerably in etiology [idiopathic, and low-tone and high-tone neuromuscular (HTNM)], age, and curve severity and progression. Treatment options were analyzed both individually and grouped as conservative (observation, bracing, or casting) versus surgical (spine-based or rib-based distraction, growth guidance, growth modulation, or definitive fusion). An "outlier" variable was created to determine the extent of a surgeon's deviation from the group in management decisions. A univariate and multivariate regression analysis to identify statistical associations between physician characteristics and their management decisions in the presented hypothetical cases was performed.

RESULTS

The cohort's mean years in practice was 20.7±7.36 years. Fifty-six percent of the cohort held Chest Wall and Spine Deformity Study Group (CWSDSG) membership and 56% were members of the Growing Spine Study Group. Multivariate regression demonstrated more years of practice predicted a lower preference for fusion (P<0.05). This effect was greater among HTNM cases (P<0.05). Overall, there was equal interest among groups regarding the choice between rib-based and spine-based distraction methods; however, for the subset of patients with HTNM scoliosis, membership in the CWSDSG (P<0.05) and the percentage of practice spent treating spinal deformity (P<0.05) predicted more rib-based distraction use.

CONCLUSIONS

EOS surgeons with more experience were less likely to opt for definitive fusion. Use of rib-based distraction methods was common across surgeons in both study groups and within various cohorts of patients.

LEVEL OF EVIDENCE

Level V (survey of experts).

Magnetically controlled growing rods for severe spinal curvature in young children: a prospective case series

BACKGROUND

Scoliosis in skeletally immature children is often treated by implantation of a rod to straighten the spine. Rods can be distracted (lengthened) as the spine grows, but patients need many invasive operations under general anaesthesia. Such operations are costly and associated with negative psychosocial outcomes. We assessed the effectiveness and safety of a new magnetically controlled growing rod (MCGR) for non-invasive outpatient distractions.

METHODS

We implanted the MCGR in five patients, two of whom have now reached 24 months' follow-up. Each patient underwent monthly outpatient distractions. We used radiography to measure the magnitude of the spinal curvature, rod distraction length, and spinal length. We assessed clinical outcome by measuring the degree of pain, function, mental health, satisfaction with treatment, and procedure-related complications.

FINDINGS

In the two patients with 24 months' follow-up, the mean degree of scoliosis, measured by Cobb angle, was 67° (SD 10°) before implantation and 29° (4°) at 24 months. Length of the instrumented segment of the spine increased by a mean of 1·9 mm (0·4 mm) with each distraction. Mean predicted versus actual rod distraction lengths were 2·3 mm (1·2 mm) versus 1·4 mm (0·7 mm) for patient 1, and 2·0 mm (0·2 mm) and 2·1 mm (0·7 mm) versus 1·9 mm (0·6 mm) and 1·7 mm (0·8 mm) for patient 2's right and left rods, respectively. Throughout follow-up, both patients had no pain, had good functional outcome, and were satisfied with the procedure. No MCGR-related complications were noted.

INTERPRETATION

The MCGR procedure can be safely and effectively used in outpatient settings, and minimises surgical scarring and psychological distress, improves quality of life, and is more cost-effective than is the traditional growing rod procedure. The technique could be used for non-invasive correction of abnormalities in other disorders.

FUNDING

Ellipse Technologies.

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.

The Vertical Expandable Prosthetic Titanium Rib in the treatment of spinal deformity due to progressive early onset scoliosis

The Vertical Expandable Prosthetic Titanium Rib (VEPTR) is a technique developed for the treatment of progressive early onset scoliosis. This vertically placed device uses distraction to indirectly elongate the spine and chest, stabilizing the progression of the spinal deformity while preserving spinal growth. Thoracic spine and chest wall deformity are usually correlated; therefore, elongation of the chest wall will increase the space available for the lung and improve respiratory mechanics in patients with early onset scoliosis. We conducted a retrospective study of 17 patients with early onset scoliosis treated with the VEPTR technique. The medical records, imaging studies, and follow-up physical examinations were evaluated. The patient population consisted of 17 primary VEPTR implantations and 33 expansion surgeries with a mean follow-up of 25 months. Our results show that there was an improvement in the coronal plane deformity between the presurgical and postsurgical Cobb angles, preoperative Cobb angle of 59 degrees (range 38-77) to postoperative 35 degrees (range 10-70), resulting in an average decrease of 59% in the Cobb angle (P<0.001). The thoracic kyphosis was maintained at anatomically normal values. The surgical technique preserved the space available for the lung. The complication rate was 13%, which includes infection, device migration, and rib fracture. The analysis of the data shows that the natural history of the progressive spinal deformity was improved in all patients. This preliminary report reaffirms that the VEPTR implantation is a safe and efficient method for the treatment of early onset scoliosis.

Dual growing rod technique followed for three to eleven years until final fusion: the effect of frequency of lengthening

STUDY DESIGN

Retrospective case review of children completing dual growing rod treatment at our institutions. Patients had a minimum of 2 years follow-up.

OBJECTIVE

To identify the factors influencing dual growing rod treatment outcome followed to final fusion.

SUMMARY OF BACKGROUND DATA

Published reports on dual growing rod technique results for early onset scoliosis demonstrate it to be safe and effective in curve correction and maintenance as well as in allowing spinal growth.

METHODS

Between 1990 and 2003, 13 patients with no previous surgery and noncongenital curves underwent final fusion. All had preoperative curve progression over 10 degrees after unsuccessful nonoperative treatment. There were 10 females and 3 males. Average age was 6.6 +/- 2.9 years at initial surgery. There were 3 idiopathic, 1 nonspine congenital anomaly, and 9 syndromic patients. Analysis included age at initial surgery and final fusion, number and frequency of lengthenings, and complications. Radiographic evaluation included changes in Cobb angle, T1-S1 length, and instrumentation length over the treatment period.

RESULTS

Cobb angle improved from 81.0 +/- 23 degrees to 35.8 +/- 15 degrees postinitial and 27.7 +/- 17 degrees after final fusion. Average number of lengthenings was 5.2 +/- 3 at an interval of 9.4 +/- 5 months. T1-S1 length increased from 24.4 +/- 3.4 to 29.3 +/- 3.6 cm postinitial and 35.0 +/- 3.7 cm postfinal fusion. Average growth was 1.46 +/- 0.66 cm/year. Those lengthened at <or=6 months (n = 7; range, 5.5-6.7 months) had a higher annual growth rate of 1.8 cm versus 1.0 cm (P = 0.018) from postinitial to postfinal and significantly greater scoliosis correction (79% vs. 48%, P = 0.007) than those lengthened less frequently (n = 6; range, 9-20 months). Six patients experienced complications: 3 within the treatment period, 2 postfinal, and 1 both during and after treatment.

CONCLUSION

Dual growing rod technique resulted in 5.7 +/- 2.9 cm of spinal growth during a 4.37 +/- 2.4 year treatment period. There was significantly greater growth and correction achieved in those lengthened more frequently.