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

A six-year observational study of 31 children with early-onset scoliosis treated using magnetically controlled growing rods with a minimum follow-up of two years

Aims

Magnetically controlled growing rod (MCGR) systems use non-invasive spinal lengthening for the surgical treatment of early-onset scoliosis (EOS). The primary aim of this study was to evaluate the performance of these devices in the prevention of progression of the deformity. A secondary aim was to record the rate of complications.

Patients and Methods

An observational study of 31 consecutive children with EOS, of whom 15 were male, who were treated between December 2011 and October 2017 was undertaken. Their mean age was 7.7 years (2 to 14). The mean follow-up was 47 months (24 to 69). Distractions were completed using the tailgating technique. The primary outcome measure was correction of the radiographic deformity. Secondary outcomes were growth, functional outcomes and complication rates.

Results

The mean Cobb angle was 54° (14° to 91°) preoperatively and 37° (11° to 69°) at the latest follow-up (p < 0.001). The mean thoracic kyphosis (TK) was 45° (10° to 89°) preoperatively and 42° (9° to 84°) at the latest follow-up. The mean T1-S1 height increased from 287 mm (209 to 378) to 338 mm (240 to 427) (p < 0.001) and the mean sagittal balance reduced from 68 mm (-76 to 1470) preoperatively to 18 mm (-32 to 166) at the latest follow-up. The mean coronal balance was 3 mm (-336 to 64) preoperatively and 8 mm (-144 to 64) at the latest follow-up. The mean increase in weight and sitting and standing height at the latest follow-up was 45%, 10% and 15%, respectively. The mean Activity Scale for Kids (ASKp) scores increased in all domains, with only personal care and standing skills being significant at the latest follow-up (p = 0.02, p = 0.03). The improvements in Cobb angle, TK and T1-S1 heights were not related to gender, the aetiology of the EOS, or whether the procedure was primary or conversion from a conventional growing rod system. A total of 21 children developed 23 complications at a rate of 0.23 per patient per year. Seven developed MCGR-specific complications. Complications developed at a mean of 38 months (3 to 67) after the initial surgery and required 22 further procedures. Children who developed a complication were more likely to be younger, have syndromic EOS, and have a single-rod construct (6.9 versus 9.3 years, p = 0.034).

Conclusion

The progression of EOS can be controlled using MCGRs allowing growth and improved function. Younger and syndromic children are more likely to develop complications following surgery. Cite this article: Bone Joint J 2018;100-B:1187-1200.

Reliability and Construct Validity of the Adapted Norwegian Version of the Early-Onset Scoliosis 24-item Questionnaire

Background:

The Early-Onset Scoliosis 24-item Questionnaire (EOSQ-24) reflects issues important for patients with early-onset scoliosis (EOS) and their parents. The aim of this study was to translate the original EOSQ-24 into Norwegian and to evaluate the resulting questionnaire's reliability and construct validity.

Methods:

The EOSQ-24 was translated using a forward-backward translation method, followed by an expert review. One hundred parents of a heterogenic group of patients with EOS answered the EOSQ-24 and scored Numeric Rating Scales (NRSs) to evaluate the children's general health, pain, and physical function. Two weeks later, 55 parents (55%) answered the retest questionnaire. Data quality, internal consistency, and test-retest reliability were assessed, including the minimal detectable change. Construct validity was evaluated by predefined hypotheses and correlations with NRS scores.

Results:

There were considerable ceiling (19.0% to 63.0%) and floor effects (zero to 26.0%). The internal consistency was excellent (Cronbach α = 0.95). The minimal detectable change for the EOSQ-24 total score was 15.2 and ranged from 21.6 to 33.0 for the subdomains scores. The EOSQ-24 showed discriminate capabilities among patients with different etiology, treatment status, and severity of deformity. High correlations were found between the EOSQ-24 total score and the NRS scores for general health (r = −0.66), pain (r = −0.63), and physical function (r = −0.78).

Conclusion:

The Norwegian version of the EOSQ-24 has acceptable reliability and validity for measuring quality of life and caregiver burden among EOS children. The EOSQ-24 total score is acceptable for evaluation of these patients over time.

Level of Evidence:

Level III, diagnostic study

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.

Outcomes of growing rod surgery for severe compared with moderate early-onset scoliosis: a matched comparative study

Aims

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

Patients and Methods

A review of a multicentre EOS database identified 107 children with severe EOS (major curve ≥ 90°) treated with growing rods before the age of ten years with a minimum follow-up of two years and three or more lengthening procedures. From the same database, 107 matched controls with moderate EOS were identified.

Results

The mean preoperative major curve was 101° (90 to 139) in the severe group and 67° (33° to 88°) in the moderate group (p < 0.001), which was corrected at final follow-up to 57° (10° to 96°) in the severe group and 40° (3° to 85°) in the moderate group (p < 0.001). T1-S1 height increased by a mean of 54 mm (-8 to 131) in the severe group and 27 mm (-4 to 131) in the moderate group at the initial surgery (p < 0.001), and by 50 mm (-17 to 200) and 54 mm (-11 to 212), respectively, during distraction (p = 0.84). The mean number of complications per patient was 2.6 (0 to 14) in the severe group and 1.9 (0 to 10) in the moderate group (p = 0.040). Five patients (4.7%) in the severe group and three (2.8%) in the moderate group developed a neurological deficit postoperatively (p = 0.47).

Conclusion

Severe EOS can be treated effectively using growing rods, but the risk of complications is high. Cite this article: Bone Joint J 2018;100-B:772-9.

Treatment strategies for early-onset scoliosis

Early-onset scoliosis (EOS) is defined as a spinal deformity occurring before the age of ten years.

Untreated EOS or early spinal fusion resulting in a short spine is associated with increased mortality and cardiopulmonary compromise.

EOS may progress rapidly, and therefore prompt clinical diagnosis and referral to a paediatric orthopaedic or spine unit is necessary.

Casting under general anaesthesia can be effective and may prevent or delay the need for surgery in curves of less than 60°.

‘Growing’ rods (traditional or magnetically-controlled) represent the standard surgical treatment in progressive curves of 45° or greater.

Children with congenital scoliosis associated with fused ribs benefit from surgery with a vertical titanium prosthetic rib.

Surgery with growth-friendly instrumentation is associated with a high risk of complications.

Cite this article: EFORT Open Rev 2018;3 DOI: 10.1302/2058-5241.3.170051

Current Use of Evidence-Based Medicine in Pediatric Spine Surgery

Evidence-based medicine (EBM) is a process of decision-making aimed at making the best clinical decisions as they relate to patients' health. The current use of EBM in pediatric spine surgery is varied, based mainly on the availability of high-quality data. The use of EBM is limited in idiopathic scoliosis, whereas EBM has been used to investigate the treatment of pediatric spondylolysis. Studies on early onset scoliosis are of low quality, making EBM difficult in this condition. Future focus and commitment to study quality in pediatric spinal surgery will likely increase the role of EBM in these conditions.

Cost analysis of a growth guidance system compared with traditional and magnetically controlled growing rods for early-onset scoliosis: a US-based integrated health care delivery system perspective

Purpose

Treating early-onset scoliosis (EOS) with traditional growing rods (TGR) is effective but requires periodic surgical lengthening, risking complications. Alternatives include magnetically controlled growing rods (MCGR) that lengthen noninvasively and the growth guidance system (GGS), which obviate the need for active, distractive lengthenings. Previous studies have reported promising clinical effectiveness for GGS; however the direct medical costs of GGS compared to TGR and MCGR have not yet been explored.

Methods

To estimate the cost of GGS compared with MCGR and TGR for EOS an economic model was developed from the perspective of a US integrated health care delivery system. Using dual-rod constructs, the model estimated the cumulative costs associated with initial implantation, rod lengthenings (TGR, MCGR), revisions due to device failure, surgical-site infections, device exchange, and final spinal fusion over a 6-year episode of care. Model parameters were from peer-reviewed, published literature. Medicare payments were used as a proxy for provider costs. Costs (2016 US$) were discounted 3% annually.

Results

Over a 6-year episode of care, GGS was associated with fewer invasive surgeries per patient than TGR (GGS: 3.4; TGR: 14.4) and lower cumulative costs than MCGR and TGR, saving $25,226 vs TGR. Sensitivity analyses showed that results were sensitive to changes in construct costs, rod breakage rates, months between lengthenings, and TGR lengthening setting of care.

Conclusion

Within the model, GGS resulted in fewer invasive surgeries and deep surgical site infections than TGR, and lower cumulative costs per patient than both MCGR and TGR, over a 6-year episode of care. The analysis did not account for family disruption, pain, psychological distress, or compromised health-related quality of life associated with invasive TGR lengthenings, nor for potential patient anxiety surrounding the frequent MCGR lengthenings. Further analyses focusing strictly on current generation technologies should be considered for future research.

Observed Length Increases of Magnetically Controlled Growing Rods are Lower Than Programmed

BACKGROUND

Magnetically controlled growing rods (MCGRs) are increasingly used in the treatment of early onset scoliosis (EOS). Few studies have reported whether desired lengthening can reliably be achieved, or if prior spine instrumentation and large tissue depths affect lengthening. In this clinical study of EOS patients, it was hypothesized that increases in rod length would equal programmed increases, patients with prior spine instrumentation would lengthen less than patients without prior surgery, and larger tissue depths would decrease lengthening success.

METHODS

A retrospective chart review was conducted on EOS patients with single and dual MCGRs placed between April 2014 to September 2015 and distracted at a single institution. Rod distraction was measured at each visit using ultrasound. Differences between programmed and actual distraction for each patient, and between groups with and without prior spine instrumentation, were determined by 2-tailed t tests. Regression and correlation were used to determine the relationship between tissue depth and length increases.

RESULTS

Thirty-one patients were included, 18 males, 13 females, age 8.1 (±2.5) years, with major curves measuring 60 (±14.6) degrees at time of MCGR insertion. In the 12 patients with prior instrumentation, time from initial growing rod placement to MCGR insertion was 23.1 (±10.6) months. The number of surgical procedures before MCGR insertion was 2.8 (±2.0). Total length increase relative to the programmed distraction was 86% (±21) (P<0.001). Length increases for patients with and without prior surgery were 87% (±23) and 86% (±19), respectively (P>0.9). Total lengthening was inversely proportional to tissue depth (r=0.38, P<0.01); the decrease in lengthening achieved was 2.1%/mm of tissue depth.

CONCLUSIONS

Increases in rod length were 14% lower than the programmed distraction. Prior instrumentation did not impact the amount of rod distraction. Greater distance between the rod and the skin surface negatively affected the magnitude of distraction.

What's New in Congenital Scoliosis?

BACKGROUND

Congenital scoliosis is a failure of vertebral formation, segmentation, or a combination of the 2 arising from abnormal vertebral development during weeks 4 to 6 of gestation. The associated spinal deformity can be of varying severity and result in a stable or progressive deformity based on the type and location of the anomalous vertebra(e). Bracing for congenital scoliosis is rarely indicated, while recent reports have demonstrated the utility of serial derotational casting for longer curves with multiple anomalous vertebrae as an effective "time buying strategy" to delay the need for surgery. Earlier hemivertebra excision and short-segment posterior spinal fusion have been advocated to prevent future curve progression of the deformity and/or the development of large compensatory curves. It has been shown in recent long-term follow-up studies that growth rates of the vertebral body and spinal canal are not as dramatically affected by pedicle screw instrumentation at a young age as once thought. Growth friendly surgery with either spine-based or rib-based anchors has demonstrated good results with curve correction while maintaining spinal growth. Rib-based anchors are typically more commonly indicated in the setting of chest wall abnormalities and/or when spinal anatomy precludes placement of spinal instrumentation. Recently, magnetically controlled growing rods have shown promising results in several studies that include a small subset of congenital scoliosis cases.

METHODS

A literature search was performed to identify existing studies related to the treatment of congenital scoliosis published from January 1, 2005 to June 1, 2016. Databases included PubMed, Medline, and the Cochrane Library. The search was limited to English articles and yielded 36 papers. This project was initiated by the Pediatric Orthopaedic Society of North America Publications Committee and was reviewed and approved by the Pediatric Orthopaedic Society of North America Presidential Line.

RESULTS

A total of 36 papers were selected for review based upon new findings. Classic manuscripts on congenital scoliosis are also included to provide sufficient background information.

CONCLUSIONS

Congenital scoliosis represents a wide range of pathology from the simple, stable hemivertebra to the complex, progressive spinal deformity with chest wall abnormalities and associated cardiac, renal, and neural axis anomalies. This paper reviews the natural history and associated anomalies with congenital scoliosis as well as the most up-to-date classification schemes and various treatment options for the care of this challenging patient population.

LEVEL OF EVIDENCE

Level 5.

Spine and Thoracic Height Measurements Have Excellent Interrater and Intrarater Reliability in Patients With Early Onset Scoliosis

STUDY DESIGN

Reproducibility of measurements.

OBJECTIVE

This study investigates the reliability and standard error of measurement of spine and thoracic height radiographic measurements in patients with early onset scoliosis (EOS).

SUMMARY OF BACKGROUND DATA

Spine and thoracic height radiographic measurements are often used as a surrogate for pulmonary development in patients with EOS. There is limited literature validating the reliability of spine and thoracic height measurements in the EOS population.

METHODS

Using pilot data, we determined measuring 49 unique radiographs would provide 80% power to obtain a 95% confidence interval (CI) width of 0.05 for the interclass correlation coefficients (ICCs). A random sampling strategy, stratified by underlying diagnosis from the Classification of Early Onset Scoliosis (C-EOS), was used to distribute the diagnoses in the study sample. Two attending pediatric spine surgeons, two pediatric orthopedic fellows, and two research assistants measured coronal spine (T1-S1) and thoracic (T1-T12) height on digital radiographs using imaging software (Surgimap; Nemaris, Inc, New York) on two separate occasions at least 3 weeks apart. Order of images was randomized for the second iteration. Linear mixed model regression analyses were used to estimate interrater and intrarater reliability.

RESULTS

The study sample included subjects (N = 48) with idiopathic (N = 17, 35%), congenital (N = 16, 33%, 1 patient excluded), neuromuscular (N = 11, 23%), and syndromic (N = 4, 8%) scoliosis. Overall interrater reliability estimates for spine height (ICC: 0.894, 95% CI: 0.847-0.932) and thoracic height (ICC: 0.890, 95% CI: 0.844-0.929) were excellent. Intrarater reliability estimates for spine height (ICC: 0.906, 95% CI: 0.830-0.943) and thoracic height (ICC: 0.898, 95% CI: 0.817-0.938) were also excellent.

CONCLUSION

There is excellent interrater and intrarater reliability for radiographic measurements of spine and thoracic height in the EOS population at our institution.

LEVEL OF EVIDENCE

2.

Comparison of Percentile Weight Gain of Growth-Friendly Constructs in Early-Onset Scoliosis

STUDY DESIGN

Multicenter retrospective cohort.

OBJECTIVE

To compare improvement in nutritional status seen in early-onset scoliosis (EOS) patients following treatment with various growth-friendly techniques, especially in underweight patients (<20th weight percentile).

BACKGROUND

Thoracic insufficiency resulting from EOS can lead to severe cardiopulmonary disease. In this age group, pulmonary function tests are often difficult or impossible to perform. Weight gain has been used in prior studies as a proxy for improvement and has been demonstrated following VEPTR and growing rod implantation. In this study, we aim to analyze weight gain of EOS patients treated with four different spinal implants to evaluate if significant differences in weight percentile change exist between them.

METHODS

Retrospective review of patients treated surgically for EOS was performed from a multicenter database. Exclusion criteria were index instrumentation at >10 years old and <2 years' follow-up.

RESULTS

287 patients met the inclusion criteria and etiologies were as follows: congenital = 85; syndromic = 79; neuromuscular = 69; and idiopathic = 52. Average patient age at surgery was 5.41 years, with an average follow-up of 5.8 years. Preoperatively, 55.4% (162/287) fell below the 20th weight percentile. There was no significant difference in preoperative weight between implants (p = .77), or diagnoses (p = .25). Among this group, the mean change in weight percentile was 10.5% (range: -16.7% to 88.7%) and all implant groups increased in mean weight percentile at final follow-up. There were no significant differences in weight percentile change between the groups when divided by implant type (p = .17).

CONCLUSIONS

Treatment of EOS with growth-friendly constructs resulted in an increase in weight percentile for underweight patients (<20th percentile), with no significant difference between constructs.

LEVEL OF EVIDENCE

Level III.

Short Segment Spinal Instrumentation in Early-onset Scoliosis Patients Treated With Magnetically Controlled Growing Rods: Surgical Technique and Mid - Short-term Outcomes

STUDY DESIGN

A prospective, a single-institution, nonrandomized study.

OBJECTIVE

The aim of this study was to evaluate the safety and effectivity of short-segment instrumentation in early-onset scoliosis (EOS) patients treated by magnetic-controlled growing rods (MCGRs).

SUMMARY OF BACKGROUND DATA

Despite the common use of conventional growing rods and the recent popularity of MCGR in the treatment of progressive EOS, distal instrumented vertebra and number of the spanned levels are not standardized.

METHODS

Patients with progressive EOS, characterized by the major thoracic curve and nonstructural compensatory curve, were a candidate to be treated by dual MCGR short segment spinal instrumentation spanning the major thoracic curve; such patients are followed up for a minimum period of 30 months. Radiological data were collected and analyzed in terms of Cobb angle of both primary and secondary curve, kyphosis angle, T1-T12, and T1-S1 distances, and T1-T12/T1-S1 ratio in preoperative, postoperative, and last follow-up.

RESULTS

Sixteen patients with different diagnoses of EOS, mean age at the operation was 7 years and 10 months (5 years and 6 months-9 years and 10 months), and mean period of follow-up was 37 (30-54) months. The Cobb angle of both major and compensatory curve are corrected by the mean value of 62° (44-85), 35° (22-45) preoperatively to 29° (12-49), 14° (9-24) postoperatively, and maintained at 28° (10-47), 10° (2-20) in the last follow-up, respectively. The T1-T12/T1-S1 ratio was 0.58 preoperatively, 0.6 postoperatively, and 0.62 at the last follow-up. The average yearly T1-T12 and T1-S1 length increase were calculated as 7 and 9 mm/year, respectively.

CONCLUSION

Selective fusion principals are applicable to EOS, in that short segment instrumentation with MGCR in thoracic curve EOS patients is an effective technique in correction of both structural and compensatory curve, and in maintaining the correction during subsequent nonsurgical spinal distraction.

LEVEL OF EVIDENCE

4.

How Does Hyperkyphotic Early-Onset Scoliosis Respond to Growing Rod Treatment?

BACKGROUND

Growing rods (GRs) pose a higher risk of kyphosis gain while improving coronal deformity with intermittent distractions in early-onset scoliosis (EOS), but in turn, increased kyphosis may also affect GR correction outcomes. However, there is a paucity of data regarding the effect of GRs on the sagittal spinal profiles in hyperkyphotic EOS. Thus, we aim to demonstrate how hyperkyphotic EOS responds to GRs treatment.

METHODS

Forty patients treated with GRs for EOS were included and categorized into a normal kyphosis (N) group [20 degrees≤thoracic kyphosis (TK)≤50 degrees] or hyperkyphosis group (K) group (TK≥50 degrees). Radiographic measurements were performed before and after the index surgery and at the last follow-up. The complications were identified and classified using the surgical complications grading system.

RESULTS

The N group included 13 patients with dual GRs and 6 patients with a single GR. The K group consisted of 17 patients with dual GRs and 4 patients with a single GR. The mean age at surgery in the N and K groups was 6.2±1.8 and 6.4±2.1 years, respectively. The N and K groups, respectively, had an average number of lengthenings of 4.2±2.0 and 4.3±2.3, with an average follow-up of 4.7±1.9 and 4.6±2.1 years, respectively. In the K group, TK was markedly reduced after the index surgery and slightly increased during follow-up, whereas changes in TK in the N group were not significant. The complication rate in the K group was significantly higher than in the N group (81.0% vs. 47.4%, P=0.046). The most common implant-related and alignment-related complication in both groups was rod fracture (17.5%) and proximal junctional kyphosis (22.5%), respectively. The complication events in the N group were 5 with grade I and 5 with grade IIA, whereas in the K group there were 8 with grade I and 11 with grade IIA.

CONCLUSIONS

GRs can effectively correct hyperkyphotic EOS, with the sagittal profile being successfully restored to normal range. However, hyperkyphotic EOS tends to experience more complications such as rod fracture and PJK.

LEVEL OF EVIDENCE

Level III.

Staged Growing Rods With Preimplantation of Spinal Anchors for Complex Early Onset Scoliosis

BACKGROUND

Treatment of early onset scoliosis (EOS) with growing rods (GR) can be challenging in patients with significant deformity, hyperkyphosis, or poor bone quality, due to risks of neurological deficit and hardware pull-out. The objective of this study is to report a series of EOS patients managed with a 2-stage GR technique used to minimize these complications.

METHODS

Two-stage GR technique was performed in 8 patients at mean age of 5.4 (range, 3.4 to 7.9) years. At stage 1, proximal and distal anchors were implanted with local fusion. At stage 2, the distraction rods were inserted. There were at least 3 months between stages 1 and 2, and halo-gravity traction was used before stage 2 unless contraindicated. Demographic, clinical, and surgical data were retrospectively reviewed with mean 4.9 (range, 2.0 to 9.4) years of follow-up. Radiographic measurements including Cobb and kyphosis angles were evaluated before stage 1, after halo-gravity traction, after stage 2, and at last follow-up. Indications for staging, anchor healing time, and complications were collected and analyzed.

RESULTS

Indications for 2-stage surgery were poor bone quality in 5 patients and neurological changes during initial attempt at GR placement in 3 patients. The mean time between stage 1 and 2 was 23 (15 to 45) weeks. Patients have undergone mean 7 (3 to 16) lengthenings. Three patients have been converted to magnetically controlled GR. The major coronal Cobb angle improved from mean 81 degrees (range, 61 to 97) preoperatively to 40 degrees (24 to 50) after stage 2 and remained at 40 degrees (27 to 53) at last follow-up. Kyphosis remained controlled from 45 degrees (10 to 76) preoperatively to 38 degrees (9 to 61) after stage 2 to 41 degrees (17 to 65) at last follow-up. Complications included superficial wound problems (4 patients), broken rods (2 patients), proximal migration (2 patients), and implant prominence (1 patient). At minimum 2-year follow-up, no patients had lingering neurological complications or instrumentation-bone failure of the GR construct.

CONCLUSIONS

Two-stage GR technique can effectively be utilized in EOS patients with poor bone quality or in the event of intraoperative neurological changes. Satisfactory deformity correction can be obtained and routine serial lengthenings can take place with minimal complications.

LEVEL OF EVIDENCE

Level IV- case series.

Clinically apparent adverse reactions to intra-wound vancomycin powder in early onset scoliosis are rare

PURPOSE

Spine surgeons have increasingly used intraoperative application of topical vancomycin powder (TVP) to prevent surgical site infections (SSIs). The goals of this study were to define the rate of pharmacological adverse reaction to TVP in young patients undergoing posterior spinal surgery and to summarise institutional variation in TVP dosing.

METHODS

This retrospective observational study included ten spine centres in the United States and one in Europe. Patients with early onset scoliosis who underwent posterior spine surgery were eligible for inclusion. Age, weight, TVP dose and surgery type were recorded. Surgeries where patient age was > 12 years were excluded. Pharmacological adverse reactions were defined as clinical instances of Red Man Syndrome, rash, nephrotoxicity, proteinuria, hepatotoxicity or ototoxicity. The rate of pharmacological adverse reaction to TVP was calculated. Dosing practices were summarised.

RESULTS

Patient age was in the range of seven months to 12 years (median ten years). Of 1398 observations, there was one possible pharmacological adverse reaction. This was in a ten-year-old, 20.4-kg female patient with neuromuscular sco-liosis undergoing growing rod implantation. She was dosed with 1500 mg of TVP and immediately developed a transient rash without systemic symptoms. This abated over minutes without any medical intervention. There were no other adverse reactions in the sample. The population rate of pharmacological adverse reaction was 0.072% (95% confidence interval 0 to 0.4). Significant variability in dosing practices existed between centres.

CONCLUSION

Pharmacological adverse reactions to TVP are rare. Future work may establish evidence-based guidelines for TVP dosing based on patient weight and other variables.

Three-dimensional True Spine Length: A Novel Technique for Assessing the Outcomes of Scoliosis Surgery

BACKGROUND

Current assessment of spine growth for patients undergoing growth friendly surgical treatment for early-onset scoliosis (EOS) is the use of serial, 1-dimensional standard-of-care coronal vertical spine height (SoCVH) measurements. Any growth of the spine out of the coronal plane is missed by the SoCVH, which may underestimate the actual growth of the spine. This study set to validate the novel 3-dimensional true spine length (3DTSL) radiographic measurement technique for measuring growth of EOS patients.

METHODS

3DTSL measurement accuracy, reliability, and repeatability was assessed using 10 physical model configurations. In addition, interrater and intrarater reliabilities (IRRs) were assessed using interclass coefficient (ICC) analyses of 23 retrospective EOS patient clinical radiographs. 3DTSL measurements were compared with SoCVH measurements.

RESULTS

The model assessment showed excellent accuracy with a mean error of 1.2 mm (SD=0.9; range, 0.0 to 3.0) and mean ICC of 0.999.IRR ICCs of the clinical radiographs averaged 0.952 for the 3DTSL and 0.975 for the vertical height whereas IRRs averaged 0.944 and 0.965, respectively (all P<0.001).Mean clinical 3DTSL curve lengths were 193.9 mm (SD=30.0; range, 142.8 to 276.8), whereas the SoCVH averaged 156.1 mm (SD=29.7; range, 74.7 to 207.3). The mean difference between the matched 3DTSL and SoCVH measurements was 37.8 mm (SD=21.4; range, 1.3 to 95.4) and was statistically significant (P<0.0001). On average, the 3DTSL of the measured spines was 124.2% of the measured SoCVH, with a progressive difference as the Cobb or kyphosis angles increased.

CONCLUSIONS

The novel 3DTSL measurement is accurate, repeatable, and complements the current growth assessments for EOS treatments.

LEVEL OF EVIDENCE

Level II-diagnostic study-development of a diagnostic criteria on basis of consecutive patients, with gold standard.

Weight Gain After Vertical Expandable Prosthetic Titanium Rib Surgery May Be From Nutritional Optimization Rather Than Improvement in Pulmonary Function

STUDY DESIGN

Prospective comparative study.

OBJECTIVE

To evaluate whether weight percentile (WP) increases after vertical expandable prosthetic titanium rib (VEPTR) insertion, and whether WP correlates with nutrition laboratories and pulmonary function.

SUMMARY OF BACKGROUND DATA

Children with thoracic insufficiency syndrome often have "failure to thrive" (WP ≤5). Previous authors have reported an increase in WP after VEPTR surgery. Weight gain was hypothesized to be secondary to improved pulmonary function. The presence of a correlation between WP and nutrition laboratories and pulmonary function tests (PFT) after VEPTR insertion has not been studied.

METHODS

Demographic, nutrition, radiographic, and PFT data were collected on 35 VEPTR patients with a minimum follow-up of 2 years. The relationship between WP and nutrition laboratories and pulmonary function was analyzed.

RESULTS

Preoperative WP was ≤5 (PREOP≤5) in 13 patients (37%) and >5 (PREOP>5) in 22 patients (63%). Although all children gained weight, the PREOP≤5 group was more likely to have an increase in WP (P = 0.014). Sixty-eight percent of the PREOP>5 group had a decrease in WP and 32% of the PREOP>5 patients met the criteria for failure to thrive at final follow-up. Overall, there was no change in the number of children with a WP ≤5 (13 vs. 15). Forty-two percent of the children who maintained or increased their WP had a gastrostomy tube, compared to 19% of those who decreased their WP. Seventy-three percent of the patients with failure to thrive at final follow-up did not have a gastrostomy tube. No significant correlations were found between WP and nutrition laboratories, radiographic measures, or PFTs.

CONCLUSION

We did not find an overall change in WP after VEPTR insertion. We did not find any correlation between WP and nutrition laboratories or pulmonary function. Weight gain after VEPTR surgery may be secondary to nutritional optimization in high-risk patients. Children who do not have failure to thrive at presentation also require attention.

LEVEL OF EVIDENCE

2.

VEPTR Implantation to Treat Children With Early-Onset Scoliosis Without Rib Abnormalities: Early Results From a Prospective Multicenter Study

BACKGROUND

Thoracoplasty and insertion of vertical expandable prosthetic titanium rib (VEPTR) for thoracic and spine distraction has been found to be effective in the treatment of early-onset scoliosis (EOS) with ribs anomalies and congenital vertebral anomalies. The aim of this study was to evaluate the efficacy of VEPTR in preventing further progression of scoliosis without impeding spinal growth in children with progressive EOS without rib abnormalities.

METHODS

This is a prospective, multicenter, observational cohort study. Erect radiographs were analyzed for coronal and sagittal curve and height measurements at preimplant, immediate postoperative, and at 2-year follow-up.

RESULTS

Sixty-three patients met inclusion: 35 males and 28 females. Mean age at time of implantation was 6.1±2.4 years. Etiologies included congenital (n=6), neuromuscular (n=36), syndromic (n=4), and idiopathic (n=17). The mean follow-up was 2.2±0.4 years. Scoliosis (72±18 degrees) decreased after implant surgery (47±17 degrees) followed by slight increase at 2-year follow-up (57±18 degrees), P<0.0001. Kyphosis (48±22 degrees) also showed significant decrease after implantation (40±14 degrees), but increased after 2 years (48±16 degrees), P<0.0001. Coronal spine height measurements including T1-T12 (15.7±3 cm) and T1-S1 (25±6 cm) showed significant increases after implantation surgery (17.7±4 cm and 28.6±6 cm, respectively) and at 2 years (18.4±4 cm and 29.1±5 cm, respectively), P<0.0001. The increase in coronal spine height represented 144% of expected age-matched T1-T12 growth and 193% of expected age-matched T1-S1 growth. Similarly, sagittal spine length of T1-T12 and T1-S1 increased from 16.9±2.7 cm and 27.1±3.9 cm, respectively preoperatively to 19.7±3.5 cm and 31.9±5.1 cm, respectively at 2-year follow-up, P<0.0001. The instrumented spine segment continued growth from 25.8±5.2 cm after implantation to 27.4±5.3 cm at 2-year follow-up, P<0.0001. Thirty-one patients (49%) had at least 1 complication with total of 58 complications.

CONCLUSIONS

At 2-year follow-up, VEPTR was effective in treating EOS without rib abnormalities with 86% of patients having an improvement in scoliosis and 94% of patients having an increased spinal height as compared with preoperative values. This study proved that spine continues to grow after VEPTR instrumentation during the distraction phase. This amount of growth represents about 40% for T1-T12 and 31% for T1-S1 spine of the expected age-matched growth based on Dimeglio reference numbers. We find this growth important as it proves continuous spine growth with VEPTR treatment.

LEVEL OF EVIDENCE

Level II.

Patients Without Intraoperative Neuromonitoring (IONM) Alerts During VEPTR Implantation Did Not Sustain Neurological Injury During Subsequent Routine Expansions: A Retrospective Multicenter Cohort Study

BACKGROUND

The purpose of this study was to determine the rate of intraoperative neurological monitoring (IONM) alerts and neurological injury during vertical expandable prosthetic titanium rib (VEPTR) treatment and evaluate the utility of IONM during VEPTR expansion procedures in patients who have not previously had neurological injury or IONM alerts.

METHODS

After institutional review board approval, VEPTR procedures and IONM records were reviewed at 17 institutions for patients treated with VEPTR from 2005 to 2011. All consecutive cases in patients with minimum 2-year follow-up were included. Patients with prior history of growing rods or other invasive spine-based surgical treatment were excluded. Surgeries were categorized into implant, revision, expansion, and removal procedures. Cases with IONM alerts or neurological injury had additional detailed review. Descriptive statistics were used for data analysis.

RESULTS

In total, 2355 consecutive VEPTR procedures (352 patients) consisting of 299 implant, 377 revision, 1587 expansion, and 92 removal procedures were included. In total, 620 VEPTR procedures had IONM, and 539 of those had IONM records available for review. IONM alerts occurred in 9/539 procedures (1.7%): 3/192 implants (1.6%), 3/58 revisions (5.2%), and 3/258 expansions (1.2%). New neurological injury occurred in 3/2355 procedures (0.1%), 3/352 patients (0.9%). All 3 injuries were in implant procedures, only 1 had an IONM alert. All 3 had upper extremity motor deficits (1 had sensory deficit also). All had full recovery at 17, 30, and 124 days postinjury. One patient without prior neurological injury or IONM alert had an IONM alert during expansion that resolved after an increase in blood pressure. The remaining IONM alerts during expansions were all in children with prior IONM alerts during implant, revision, or exchange procedures.

CONCLUSIONS

The highest rate of neurological injury in VEPTR surgery was found for implant procedures. There were no instances of neurological injury during VEPTR expansion, revision, or removal procedures. IONM did not identify new neurological injuries in patients undergoing VEPTR expansion who did not previously have a history of IONM signal change or neurologic injury.

LEVEL OF EVIDENCE

Level IV-diagnostic study.

Quantifying the ‘law of diminishing returns’ in magnetically controlled growing rods

Aims

Magnetically controlled growing rods (MCGRs) allow non-invasive correction of the spinal deformity in the treatment of early-onset scoliosis. Conventional growing rod systems (CGRS) need repeated surgical distractions: these are associated with the effect of the ‘law of diminishing returns’. The primary aim of this study was to quantify this effect in MCGRs over sequential distractions.

Patients and Methods

A total of 35 patients with a maximum follow-up of 57 months were included in the study. There were 17 boys and 18 girls with a mean age of 7.4 years (2 to 14). True Distraction (TD) was determined by measuring the expansion gap on fluoroscopy. This was compared with Intended Distraction (ID) and expressed as the ‘T/I’ ratio. The T/I ratio and the Cobb angle were calculated at several time points during follow-up.

Results

The mean follow-up was 30 months (6 to 57). There was a significant decrease in the mean T/I ratio over time (convex rod at 3 months 0.81, sd 0.58 vs 51 months 0.17, sd 0.16, p = 0.0001; concave rod at 3 months 0.93, sd 0.67 vs 51 months 0.18, sd 0.15, p = 0.0001). A linear decline of the mean T/I ratios was noted for both convex rods (r2 = 0.90, p = 0.004) and concave rods (r2 = 0.81, p = 0.015) over 51 months. At the 24-month follow-up stage, there was a significant negative correlation between the mean T/I ratio of the concave rod with weight (r = -0.59, p = 0.01), age (r = -0.59, p = 0.01), and BMI of the child (r = -0.54, p = 0.01).

Conclusions

The ‘law of diminishing returns’ is also seen after serial distraction using MCGR. Compared to previously published data for CGRS, there is a gradual linear decline rather than a rapid initial decline in lengthening. In older, heavier children a reduced distraction ratio in the concave rod of the MCGR device is noted over time. Cite this article: Bone Joint J 2017;99-B:1658–64.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

LEVEL OF EVIDENCE

Level III.

Classification of Early Onset Scoliosis has Excellent Interobserver and Intraobserver Reliability

BACKGROUND

Classification systems can be useful tools for clinical care and research but must be proven as reliable. The purpose of this study was to evaluate the interobserver and intraobserver reliability of the Classification of Early Onset Scoliosis (C-EOS) scheme.

METHODS

After IRB approval, 50 cases were drawn from a prospectively collected database of patients with EOS. Cases were selected using a stratified randomization scheme based on etiology. These cases were used to create an internet survey that was sent to pediatric orthopaedic faculty, research coordinators, and fellows involved in EOS care and research. Participants were asked to classify each case and were provided with a written C-EOS scheme that could be referenced while they completed the survey. Surveys were sent to participants twice, 3 weeks apart, to assess both intraobserver and interobserver reliability. Fleiss κ and Cohen κ were used to assess interobserver and intraobserver reliability, respectively.

RESULTS

There were 36 total participants, 29 who completed the survey twice (21 faculty, 13 research coordinators, and 2 fellows). Overall Fleiss κ coefficient for interobserver reliability was excellent across the major categories of etiology (0.84), major curve (0.93), and kyphosis (0.96). Overall intraobserver reliability was excellent with Cohen κ values for etiology (0.92), major curve (0.96), and kyphosis (0.98). Faculty members had excellent agreement for etiology (0.90), major curve (0.91), and kyphosis (0.96). Research coordinators had high levels of agreement for etiology (0.78), and excellent for major curve (0.95) and kyphosis (0.96). Intraobserver reliability was excellent across all major categories for all groups: faculty, research coordinators, and fellows.

CONCLUSIONS

The study shows high levels of interobserver and intraobserver agreement of the C-EOS scheme. The C-EOS scheme can be used as a reliable tool for classifying EOS patients for clinical communication and research.

LEVEL OF EVIDENCE

Level II-diagnostic study.

Magnetic Controlled Growing Rods as a Treatment of Early Onset Scoliosis: Early Results With Two Patients

STUDY DESIGN

Prospective unicentral nonrandomized study.

OBJECTIVE

To evaluate the safety and effectivity profile of magnetic controlled growing rods (MCGR) in patients with early onset scoliosis (EOS).

SUMMARY OF BACKGROUND DATA

Conventional growing rods are the most commonly used growth sparring devices in the treatment of EOS, as this technique requires repeated surgical operations for lengthening; it is associated with high rate of complications and increased costs. MCGR in treatment of EOS is effective in correcting deformity whereas allowing continuous spinal growth as reported by a few studies.

METHODS

A total of 18 patients with progressive EOS were treated by MCGR, two of them had undergone final fusion operation. Patients were followed-up for a minimium time of 9 months from the time of initial surgery. Radiological data were analyzed in terms of Cobb angle, kyphosis angle, T1-T12, and T1-S1 distances in preoperative, postoperative, and last follow up.

RESULTS

The mean preoperative Cobb and kyphosis angle were 68° (44-116°) and 43° (98-24°), it was corrected to 35° (67-12°) and 29° (47-21°) immediately after initial operation and maintained at 34.5° (52-10°) and 33° (52-20°) at last follow up, respectively.The mean preoperative T1-T12 and T1-S1 distance were 171 mm (202-130 mm) and 289 mm (229-370 mm), it was increased to 197 mm (158-245 mm) and 330 mm (258-406mm) immediately after initial operation and further increased to 215 mm (170-260 mm) and 357 mm (277-430 mm) at last follow up, respectively.Two patients had undergone final fusion, they had overall mean Cobb angle correction of 66° (62-70°), and kyphosis angle change of 53° (26-80°). Total height gain in T1-T12 and T1-S1 of 80.5 mm (67-94 mm) and 119 mm (105-133 ), respectively.

CONCLUSION

MCGR is safe and effective technique in correction of EOS deformity and in maintaining the correction during nonsurgical distraction procedures. A further correction of the deformity and more spinal height gain can be achieved in the final fusion operation.

LEVEL OF EVIDENCE

3.

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.

Complications and Radiographic Outcomes of Posterior Spinal Fusion and Observation in Patients Who Have Undergone Distraction-Based Treatment for Early Onset Scoliosis

STUDY DESIGN

Retrospective, multicenter.

OBJECTIVES

To compare surgical and radiographic outcomes of early-onset scoliosis (EOS) patients who had stopped lengthening for ≥2 years without additional surgery to those who had posterior spinal fusion (PSF) at the end of lengthening.

SUMMARY OF BACKGROUND DATA

Because of the risk of significant complications with PSF in patients with EOS, "watchful waiting" at the end of lengthening has been suggested as a viable alternative.

METHODS

Retrospective review of the Children's Spine Study Group (CSSG) database identified all patients with the diagnosis of EOS who had distraction-based treatment, who were ≥2 years from their last distraction, and who had complete records. Radiographic measures were obtained by a single unbiased trained observer. Treatment outcomes including curve correction, height and length gain, as well as complications were recorded.

RESULTS

The 37 patients (21 females and 16 males) had a mean age of 7.2 years; 12 were in the observation (OBS) and 25 in the PSF group. The PSF group had a slightly greater coronal Cobb angle and maximal kyphosis at the end of distraction. Although there was some correction of the coronal Cobb angle and maximal kyphosis following PSF, the differences between the two groups were not statistically significant at final follow-up. At final follow-up, the OBS group obtained 88% of T1-T12 height and 90% of T1-L1 length of that obtained by the PSF group. Twenty-six complications occurred in 15 patients, all in the PSF group.

CONCLUSIONS

Observation may be a viable alternative to PSF after distraction-based treatment in a subset of patients with EOS. PSF was found to provide no significant curve correction or gains in spine height and length compared to observation and carries a significant risk of complications.

LEVEL OF EVIDENCE

Level III, therapeutic.

Cost analysis of magnetically controlled growing rods compared with traditional growing rods for early-onset scoliosis in the US: an integrated health care delivery system perspective

Purpose

Traditional growing rod (TGR) for early-onset scoliosis (EOS) is effective but requires repeated invasive surgical lengthenings under general anesthesia. Magnetically controlled growing rod (MCGR) is lengthened noninvasively using a hand-held magnetic external remote controller in a physician office; however, the MCGR implant is expensive, and the cumulative cost savings have not been well studied. We compared direct medical costs of MCGR and TGR for EOS from the US integrated health care delivery system perspective. We hypothesized that over time, the MCGR implant cost will be offset by eliminating repeated TGR surgical lengthenings.

Methods

For both TGR and MCGR, the economic model estimated the cumulative costs for initial implantation, lengthenings, revisions due to device failure, surgical-site infections, device exchanges (at 3.8 years), and final fusion, over a 6-year episode of care. Model parameters were estimated from published literature, a multicenter EOS database of US institutions, and interviews. Costs were discounted at 3.0% annually and represent 2015 US dollars.

Results

Of 1,000 simulated patients over 6 years, MCGR was associated with an estimated 270 fewer deep surgical-site infections and 197 fewer revisions due to device failure compared with TGR. MCGR was projected to cost an additional $61 per patient over the 6-year episode of care compared with TGR. Sensitivity analyses indicated that the results were sensitive to changes in the percentage of MCGR dual rod use, months between TGR lengthenings, percentage of hospital inpatient (vs outpatient) TGR lengthenings, and MCGR implant cost.

Conclusion

Cost neutrality of MCGR to TGR was achieved over the 6-year episode of care by eliminating repeated TGR surgical lengthenings. To our knowledge, this is the first cost analysis comparing MCGR to TGR – from the US provider perspective – which demonstrates the efficient provision of care with MCGR.

Sagittal Spine Length Measurement: A Novel Technique to Assess Growth of the Spine

STUDY DESIGN

The accuracy and repeatability of a novel sagittal spine length (SSL) radiographic measurement was examined using photographic and radiographic imaging.

OBJECTIVES

To validate the new SSL technique for measuring growth in early-onset scoliosis (EOS) patients.

SUMMARY OF BACKGROUND DATA

Current assessment of patient growth undergoing growth-friendly surgical treatment for EOS is the use of serial vertical spine height measurements (VH) on coronal radiographs. Spine-based distraction implants are able to control the coronal plane deformity of scoliosis, but exhibit a "law of diminishing returns" in the impact of each follow-up lengthening surgery. As these treatments are kyphogenic, we hypothesize that the increase in kyphosis is, in fact, growth out of plane, not captured by standard spine height measurements.

METHODS

Measurement accuracy was assessed using 6 spine model alignments and clinical radiographs of 23 retrospective EOS patients. Inter- and intrarater reliabilities were assessed using interclass coefficient (ICC) analyses. The discrepancy between the VH and SSL was also investigated.

RESULTS

The model assessment showed excellent accuracy, with a 1.54 mm (SD: 1.07, range: 0.03-3.14, p = .226) mean error and mean ICCs of 0.999. As the kyphosis increased, a progressive difference between the phantom VH and SSL was observed. Interrater reliability ICCs of the clinical radiographs averaged 0.981 and 0.804, whereas intrarater reliabilities averaged 0.966 and 0.826, for the coronal and sagittal radiographs, respectively. Mean clinical SSLs were 177.5 mm (SD: 28.5, range: 114.3-250.3), whereas the VH averaged 161.6 mm (SD: 31.8, range: 58.5-243.0), resulting in a 16.0-mm (SD: 16.7, range: 0.3-90.3, p < .0001) difference between the two measurements with a progressive difference as the kyphosis increased.

CONCLUSIONS

The novel SSL measurement is accurate, repeatable, and complements the current growth assessments for EOS treatments. Until sagittal spine lengths are taken into consideration, the "law of diminishing returns" should be interpreted with caution.

LEVEL OF EVIDENCE

Level II - Prospective Comparative Study.

The Rotterdam Foot Classification: A Classification System for Medial Polydactyly of the Foot

BACKGROUND

Polydactyly at the medial side of the foot ("medial polydactyly" of the foot) is a rare and diverse congenital anomaly. In order to plan and evaluate surgical treatment, the classification of medial polydactyly is useful. The aim of our study was to develop a reliable and valid classification system for medial polydactyly of the foot that is more useful than previous systems for preoperative evaluation and surgical planning.

METHODS

A review of the literature and the clinical experience of a single experienced surgeon were used to determine classification categories. We identified all patients with medial polydactyly who had preoperative radiographs and clinical photographs and were treated at our hospital between 1993 and 2014. All affected feet were assessed according to our proposed classification system, the Rotterdam foot classification. The intrarater and interrater reliability among 5 observers who evaluated 30 feet were assessed with use of the Cohen kappa (κ) statistic.

RESULTS

We developed a classification system that describes duplication type, syndactyly, the presence of a hypoplastic ray, and deviation of the hallux. Seventy-three feet were classified according to the system. Seven duplication types were distinguished. Complete metatarsal duplication was most frequently seen (in 29%). Twelve feet showed a broad hallux without external expression of duplication. Syndactyly between medial and lateral (duplicate) halluces was present in 30 feet; between the lateral hallux and second toe, in 13 feet; and between both duplicated halluces and the lateral hallux and second toe, in 21 feet. A hypoplastic ray was seen in 75% of the feet. Intrarater agreement for duplication, hypoplastic rays, syndactyly, and deviation were, respectively, κ = 0.79, 0.75, 0.59, and 0.78. Interrater agreement for duplication, hypoplastic rays, syndactyly, and deviation were, respectively, κ = 0.72, 0.54, 0.48, and 0.64.

CONCLUSIONS

The proposed classification system contains 4 categories of anatomic features of the foot. Classification of all categories shows moderate to good reliability. Use of the Rotterdam classification in evaluating medial polydactyly improves type-specific description, which may, in the future, enhance the evaluation of surgical treatment.

CLINICAL RELEVANCE

The Rotterdam foot classification system is a reliable and easy-to-use system that we believe will improve communication between clinicians and researchers and facilitate the evaluation of treatment results in medial polydactyly of the foot.

New developments in the treatment of early-onset spinal deformity: role of the Shilla growth guidance system

Early-onset scoliosis is a complex condition with multiple facets. The goal of treating any spinal deformity is to improve the condition of the patient with the least intervention necessary. A system that allows for continuation of natural spinal growth while correcting the deformity should be the goal of treating this complex condition. The SHILLA growth guidance system allows for continued growth of the pediatric spine while correcting and guiding the apex and guiding the future growth of the curvature. The system involves selective fusion across the apex of the curvature, and minimally invasive instrumentation is then used above and below the apex to allow for continued growth of the spine. A review of recent literature on the SHILLA growth guidance system shows promising results. Early animal models showed continued growth across unfused levels with minimal facet articular damage. Comparative studies to traditional growing rods showed significantly less total surgeries along with comparable correction and longitudinal growth. The SHILLA growth guidance system is a good option for this complex patient group. Results are comparable with other growing constructs with significantly less operative interventions. The SHILLA system allows for natural growth of the pediatric spine while correcting the scoliotic deformity in a minimally invasive method. The goal of this article is to present a comprehensive review of the SHILLA system surgical technique and the associated literature concerning this topic.

Preliminary comparison of primary and conversion surgery with magnetically controlled growing rods in children with early onset scoliosis

PURPOSE

Non-invasive distraction of magnetically controlled growing rods (MCGR) avoids repeated surgical lengthening in patients with early onset scoliosis, but it is not known how effective this technique is in previously operated children.

METHODS

In a retrospective, multicentre study, the data were obtained for 27 primary (P) patients [mean age 7.0 (2.4-10.7) years at surgery] and 23 conversion (C) patients [mean age 7.7 (3.6-11.0) years at conversion from standard growing rods] with 1-year follow-up.

RESULTS

The mean major curve was 63.9° in the P group and 46.5° in the C group at baseline (preoperatively, p = 0.0009) and 39.5° and 39.6°, respectively, at 1-year follow-up (p = 0.99). The mean percentage change of spinal growth from baseline to 1-year follow-up was 18.3 % in the P group and 6.5 % in the C group (p = 0.007). Comparing the spinal growth from postoperative to 1-year follow-up no statistical difference was observed between the study groups (1.8 % P vs -2.2 % C, p = 0.09).

CONCLUSIONS

Scoliosis can be equally controlled after conversion from traditional growing rods into MCGR, but spinal growth from baseline is less in the conversion patients as compared with the primary group.

LEVEL OF EVIDENCE

III.

Low Pelvic Incidence Is Associated With Proximal Junctional Kyphosis in Patients Treated With Growing Rods

STUDY DESIGN

Retrospective review of a prospectively collected pediatric orthopedic spine database.

OBJECTIVE

To investigate whether pelvic incidence (PI) changes during growing rod treatment and to report the effects of PI, if any, on complications during treatment.

SUMMARY OF BACKGROUND DATA

Growing rods have been demonstrated to correct spinal deformity in early onset scoliosis while allowing for spinal growth. There has been little investigation into the potential effects, if any, of abnormal PI on complications, especially proximal junctional kyphosis (PJK).

METHODS

We retrospectively reviewed clinical and surgical data from our prospectively collected pediatric orthopedic spine database. Our final cohort of 48 patients had at least one lateral radiograph throughout the course of treatment containing the femoral heads and sacral endplate, and a minimum follow-up of 2 years. Defined failures were identified prospectively. Radiographs were measured for PI and development of PJK.

RESULTS

Mean age at initial treatment was 6.9 years (range 2.8-10.8 yr), with 35 females and 13 males. The mean length of follow-up was 8.1 years (range 2.0-22.1 yr). No statistical change in PI was observed throughout this study (P = 0.655). Development of any failure as well as total number of failures was associated with younger age at initial treatment (P < 0.0005 for both). Development of PJK was associated with younger age at initial treatment (P = 0.030), female sex (P = 0.002), and lower mean PI (P = 0.042).

CONCLUSION

PI remains constant throughout growth and the course of treatment with growing rods. Low PI was associated with increased PJK. When using growing rods in early onset scoliosis patients with decreased PI, increased attention should be paid to sagittal plane balance in an attempt to avoid PJK.

LEVEL OF EVIDENCE

4.

Outcomes of Pelvic Fixation in Growing Rod Constructs: An Analysis of Patients With a Minimum of 4 Years of Follow-up

STUDY DESIGN

Retrospective review.

OBJECTIVE

To evaluate which distal anchors in growing rod (GR) constructs optimally correct major curve, pelvic obliquity, sagittal alignment, T1-S1 length, thoracic kyphosis, and lumbar lordosis with the fewest complications at 4 or more years' postoperative follow-up.

SUMMARY OF BACKGROUND DATA

Pelvic fixation to the ilium and/or sacrum in GR constructs is used to treat patients with early-onset scoliosis. No studies have evaluated radiographical outcomes and complications in these patients at 4 or more years' follow-up.

METHODS

Included were 38 patients from a multicenter early-onset-scoliosis database with dual GRs anchored to the pelvis. Radiographic data included major curve, T1-S1 length, T5-T12 kyphosis, lordosis, sagittal alignment, and pelvic obliquity at preoperative and latest follow-up time points. Complications were evaluated for all anchor subtypes.

RESULTS

Mean follow-up time was 5.3 ± 0.1 years. GRs with distal anchors to the ilium significantly improved major curve (49%, p = .013) and pelvic obliquity (78%, p = .035) compared with constructs anchored to the sacrum only. Constructs with iliac fixation with S1 screws provided greater correction of lumbar kyphosis than constructs with iliac fixation and no S1 screws (p = .023). Constructs with a single caudal crosslink had a greater T1-S1 length at latest follow-up than constructs with combined cephalad and caudal crosslinks (p = .027). There were no significant differences in the rates of infection or instrumentation failure between iliac and sacral fixation groups. GR constructs with distal anchors that used a posterior superior iliac spine start point had a higher infection rate (60%) than those inserted via a sacral-alar-iliac technique (7%) (p = .002).

CONCLUSIONS

GR constructs anchored to the ilium provide significant improvements in the major curve and pelvic obliquity at a minimum of 4 years of follow-up versus constructs anchored to the sacrum alone.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Variability of Surgical Site Infection With VEPTR at Eight Centers: A Retrospective Cohort Analysis

STUDY DESIGN

Retrospective review.

OBJECTIVES

To describe clinical characteristics and infection rates in modern vertical expandable prosthetic titanium rib (VEPTR) surgery.

SUMMARY OF BACKGROUND DATA

Prior studies have demonstrated infection rates from 10% to 30% with VEPTR surgery.

METHODS

A retrospective query was done on an institutional review board-approved, multicenter prospectively collected database for patients implanted with VEPTR from 2007 to 2013 at eight sites. This identified 213 patients with appropriate data for analysis. Average follow-up was 4.1 years (range 1.7-6.3). Data collected included a Classification of Early-Onset Scoliosis (C-EOS) diagnosis, American Society of Anesthesiologists Physical Status (ASA-PS), major Cobb angle, construct type, clinical symptoms, and microbiology. The distribution of infection rates across all the study sites was compared. The exact p value was estimated by Monte Carlo simulation.

RESULTS

Overall, 18% (38/213) of patients implanted with VEPTR developed infection requiring operative debridement. There were significantly different infection rates among the sites, ranging from 2.9% to 42.9% (p = .029). The average time to infection was 70 days (range 8-236) after the infecting procedure. The majority of infections were due to gram-positive bacteria (80%, 44/55), the most prevalent being methicillin-sensitive Staphylococcus aureus (45%, 25/55). There were 20 patients (53%, 20/38) with either partial or complete implant removal to resolve infection; however, only 3 of 38 (8%) of these resulted in abandonment of VEPTR treatment. There was no difference in infection rate across the primary C-EOS diagnosis categories (p = .21) or based on ASA score (p = .53). After controlling for study site, the odds ratio of an infection following an implant procedure versus an expansion was 2.8 (p = .002). There was no difference in the odds ratio of an infection between the other procedure types (implant, expansion, exchange/revision).

CONCLUSIONS

There were significant differences in infection rates between sites. The variability in infection rate indicates a need for guided efforts to standardize best practices for infection control in VEPTR surgery.

LEVEL OF EVIDENCE

III, therapeutic study.

Early-Onset Scoliosis: A Review of History, Current Treatment, and Future Directions

Early-onset scoliosis (EOS) is defined as curvature of the spine in children >10° with onset before age 10 years. Young children with EOS are at risk for impaired pulmonary function because of the high risk of progressive spinal deformity and thoracic constraints during a critical time of lung development. The treatment of EOS is very challenging because the population is inhomogeneous, often medically complex, and often needs multiple surgeries. In the past, early spinal fusion was performed in children with severe progressive EOS, which corrected scoliosis but limited spine and thoracic growth and resulted in poor pulmonary outcomes. The current goal in treatment of EOS is to maximize growth of the spine and thorax by controlling the spinal deformity, with the aim of promoting normal lung development and pulmonary function. Bracing and casting may improve on the natural history of progression of spinal deformity and are often used to delay surgical intervention or in some cases obviate surgery. Recent advances in surgical implants and techniques have led to the development of growth-friendly implants, which have replaced early spine fusion as the surgical treatment of choice. Treatment with growth-friendly implants usually requires multiple surgeries and is associated with frequent complications. However, growth-friendly spine surgery has been shown to correct spinal deformity while allowing growth of the spine and subsequently lung growth.

The effect of vertical expandable prosthetic titanium rib on growth in congenital scoliosis

Aims:

In the treatment of thoracic insufficiency syndrome, the main aim is to maintain spinal and thoracic growth in order to continue respiratory functions. Vertical expandable prosthetic titanium rib (VEPTR) device application is a method of choice especially in the congenital cases with a thoracic deformity. In our study, we evaluated the effect of VEPTR on growth in congenital scoliosis.

Materials and Methods:

Four female patients in whom VEPTR was applied were retrospectively evaluated. Anteroposterior (AP) and lateral Cobb angles that were measured preoperatively and during the last control, space available for lung (SAL), T1-S1 and T1-T12 distances, coronal and sagittal balances were compared.

Results:

Four female patients in whom VEPTR was applied were retrospectively evaluated. AP and lateral Cobb angles that were measured preoperatively and during the last control, SAL, T1-S1, and T1-T12 distances, coronal and sagittal balances were compared.

Conclusions:

VEPTR may provide a good correction, and we observed a growth in the spine height and SAL following the treatment of congenital deformities. Long-term, multicenter, prospective studies that compare the spinal height, respiratory functions, the severity of the deformity, and the spinal balance are required in order to evaluate the efficacy of VEPTR.

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.

Traditional Growing Rods Versus Magnetically Controlled Growing Rods for the Surgical Treatment of Early-Onset Scoliosis: A Case-Matched 2-Year Study

INTRODUCTION

Traditional growing rod (TGR) surgery is a treatment technique commonly used for progressive early-onset scoliosis. Studies have shown that repeated TGR lengthenings can significantly increase the risk of complications. Magnetically controlled growing rods (MCGR) are currently available outside of the United States and early results have been promising. The purpose of this study was to compare the effectiveness of MCGR versus TGR for the treatment of early-onset scoliosis.

METHODS

Magnetically controlled growing rod patients were selected based on the following criteria: aged less than 10 years, major curve greater than 30°, thoracic height less than 22 cm, no previous spine surgery, and minimum 2-year follow-up. A total of 17 MCGR patients met the inclusion criteria, 12 of whom had complete data available for analysis. Each MCGR patient was matched with a TGR patient by etiology, gender, single versus dual rods, preoperative age, and preoperative major curve.

RESULTS

Magnetically controlled growing rod patients had a mean age of 6.8 years and mean follow-up of 2.5 years. Mean follow-up was greater for TGR patients by 1.6 years. Major curve correction was similar between MCGR and TGR patients throughout treatment. The MCGR patients experienced an average of 8.1 mm/year increase in T1-S1 during the lengthening period, compared with 9.7 mm/year for TGR patients (p = .73). There was a mean increase in T1-T12 of 1.5 mm/year for MCGR patients and 2.3 mm/year for TGR patients (p = .83). The TGR patients had 73 open surgeries, 56 of which were lengthenings. The MCGR patients had 16 open surgeries and 137 noninvasive lengthenings. Three TGR patients underwent 5 unplanned revision surgeries whereas 3 MCGR patients underwent 4 unplanned revisions.

CONCLUSIONS

Major curve correction was similar between MCGR and TGR patients throughout treatment. Annual T1-S1 and T1-12 growth was also similar between groups. The MCGR patients had 57 fewer surgical procedures than TGR patients. Incidence of unplanned surgical revisions as a result of complications was similar between groups.