Medical and congenital comorbidities associated with spinal deformities in the immature spine

Factors Related to Proximal Junctional Kyphosis and Device Failure in Patients with Early-Onset Scoliosis Treated with a Traditional Dual Growing Rod: A Single Institution Study

STUDY DESIGN

Observational study.

PURPOSE

Investigation of factors related to proximal junctional kyphosis (PJK) and device failure in patients with early-onset scoliosis.

OVERVIEW OF LITERATURE

The use of growth-friendly devices, such as traditional dual growing rod (TDGR) for the treatment of earlyonset scoliosis (EOS), may be associated with important complications, including PJK and device failure.

METHODS

Thirty-five patients with EOS and treated with TDGR from 2014 to 2021 with a minimum follow-up of 2 years were retrospectively evaluated. Potential risk factors, including demographic factors, disease etiology, radiological measurements, and surgical characteristics, were assessed.

RESULTS

PJK was observed in 19 patients (54.3%), and seven patients (20%) had device failure. PJK was significantly associated with global final kyphosis change (p=0.012). No significant correlation was found between the rod angle contour, type of implant, connector design, and the risk of PJK or device failure.

CONCLUSIONS

Treatment of EOS with TDGR is associated with high rates of complications, particularly PJK and device failure. The device type may not correlate with the risk of PJK and device failure. The progression of thoracic kyphosis during multiple distractions is an important risk factor for PJK.

Reproducibility of the classification of early onset scoliosis (C-EOS)

STUDY DESIGN

Reproducibility study.

OBJECTIVES

Assess the agreement and reliability of the classification of early onset scoliosis (C-EOS). C-EOS is a promising tool for patients with early onset scoliosis (EOS). However, the reliability has only been examined without measuring radiographs and not including the annual progression rate (APR) modifier.

METHODS

We included a single-center consecutive cohort of patients diagnosed with EOS seen in our outpatient clinic. Patients had no previous spine surgery. Four raters rated 60 cases. Two anterior-posterior full-spine radiographs, taken minimum 6 months apart, and one sagittal radiograph were measured twice by all raters in a blinded test-retest setup. Results were assessed using crude frequency of overall agreement (OA), intra- and inter-rater Fleiss kappa (κ) statistics, and intraclass correlation coefficient (ICC). We calculated the 95% limits of agreement (LOA) for major curve angle (MCA), kyphosis, and APR using a linear mixed-effects model. Inter- and intra-rater LOA were analyzed for each etiology separately.

RESULTS

Mean age was 8.7 ± 3.4 years and the etiology were congenital/structural (n = 20), idiopathic (n = 19), neuromuscular (n = 13), or syndromic (n = 8). For etiology, OA was 75.8% and κ = 0.80. For major curve angle, OA was 84.2%, κ = 0.86, ICC = 0.97, and LOA = 12.8°. For kyphosis, OA was 55.8%, κ = 0.52, ICC = 0.87, and LOA = 20.6°. For APR, OA was 76.7%, κ = 0.61, ICC = 0.77, and LOA = 17.4°/year. Inter- and intra-rater LOA were generally largest for neuromuscular and smallest for idiopathic patients.

CONCLUSIONS

We found substantial agreement for etiology, however, with disagreement in certain cases. The reliability of MCA was excellent; however, somewhat lower for kyphosis and APR with less accuracy. The measurement errors of MCA, kyphosis, and APR depended largely on the etiology. Regarding APR, LOA exceeded the 10°/year increments proposed in the C-EOS, suggesting a revision of this optional modifier.

LEVEL OF EVIDENCE

Diagnostic study level 1.

Impact of presenting patient characteristics on surgical complications and morbidity in early onset scoliosis

This study sought to assess comorbidity profiles unique to early-onset-scoliosis (EOS) patients by employing cluster analytics and to determine the influence of isolated comorbidity clusters on perioperative complications, morbidity and mortality using a high powered administrative database. The KID database was queried for ICD-9 codes pertaining to congenital and idiopathic scoliosis from 2003, 2006, 2009, 2012. Patients <10 y/o (EOS group) were included. Demographics, incidence and comorbidity profiles were assessed. Comorbidity profiles were stratified by body systems (neurological, musculoskeletal, pulmonary, cardiovascular, renal). K-means cluster and descriptive analyses elucidated incidence and comorbidity relationships between frequently co-occurring comorbidities. Binary logistic regression models determined predictors of perioperative complication development, mortality, and extended length-of-stay (≥75th percentile). 25,747 patients were included (Age: 4.34, Female: 52.1%, CCI: 0.64). Incidence was 8.9 per 100,000 annual discharges. 55.2% presented with pulmonary comorbidities, 48.7% musculoskeletal, 43.8% neurological, 18.6% cardiovascular, and 11.9% renal; 38% had concurrent neurological and pulmonary. Top inter-bodysystem clusters: Pulmonary disease (17.2%) with epilepsy (17.8%), pulmonary failure (12.2%), restrictive lung disease (10.5%), or microcephaly and quadriplegia (2.1%). Musculoskeletal comorbidities (48.7%) with renal and cardiovascular comorbidities (8.2%, OR: 7.9 [6.6-9.4], p < 0.001). Top intra-bodysystem clusters: Epilepsy (11.7%) with quadriplegia (25.8%) or microcephaly (20.5%). Regression analysis determined neurological and pulmonary clusters to have a higher odds of perioperative complication development (OR: 1.28 [1.19-1.37], p < 0.001) and mortality (OR: 2.05 [1.65-2.54], p < 0.001). Musculoskeletal with cardiovascular and renal anomalies had higher odds of mortality (OR: 1.72 [1.28-2.29], p < 0.001) and extLOS (OR: 2.83 [2.48-3.22], p < 0.001). EOS patients with musculoskeletal conditions were 7.9x more likely to have concurrent cardiovascular and renal anomalies. Clustered neurologic and pulmonary anomalies increased mortality risk by as much as 105%. These relationships may benefit pre-operative risk assessment for concurrent anomalies and adverse outcomes. Level of Evidence: III - Retrospective Prognostic Study.

Incidence, trends, and associated risks of developmental hip dysplasia in patients with Early Onset and Adolescent Idiopathic Scoliosis

Introduction

Early Onset and Adolescent Idiopathic Scoliosis, relatively common diagnoses (∼3% general population), have been associated with developmental dysplasia of the hip (DDH); a more rare spectrum of anomalies related to the abnormal development of acetabulum, proximal femur, and hip joint. To the best of our knowledge, no high powered investigations have been performed in an attempt to assess incidence and associated risks of DDH in scoliosis patients.

Methods

The KID database was queried for ICD-9 codes from 2003 to 2012 pertaining to EOS (Congenital and Idiopathic <10y/o) and AIS patients. Descriptive analysis assessed patient demographics and yearly trends in hip dysplasia rates. EOS and AIS patients with hip dysplasia were isolated, and incidence of hospital admissions for associated anomalies (osteonecrosis, osteoarthritis, recurrent hip dislocation, hip ankylosis) and hip arthroplasty (total + partial) were investigated. Univariate analysis of hip pathology determined significant predictors of hip arthroplasty. Binary logistic regression analysis was used to determine the relationship between these predictors.

Results

111,827 scoliosis patients (EOS: 25,747; AIS: 77,183) were included. AIS patients were older (15.2 vs 4.3), more female (64.2% vs 52.1%), had a higher CCI (0.84 vs 0.64), and less racially diverse (all p < 0.001). The incidence of hip dysplasia was 1.4% for AIS patients and 3.9% for EOS patients (p < 0.001). Of the AIS (n = 1073) and EOS (n = 1005) patients with hip dysplasia, 0.3% (p > 0.05 between groups) developed hip osteonecrosis, 0% of patients were coded as having a hip labral tear, hip ankylosis, and 0.6% (EOS: 0.2%; AIS: 0.9%, p = 0.025) developed hip osteoarthritis. AIS patients were more likely to have recurrent hip dislocations (35.4% vs 17.0%, p < 0.001), and both groups had similar primary hip arthroplasty rates (6.7% vs 5.4%, p = 0.118) and revision hip arthroplasty rates (0% vs 0.4%, p = 0.053). Hip osteoarthritis (OR: 13.43[5.21-34.66], p=<0.001) and older age (OR: 1.039[1.007-1.073], p = 0.017) were the only significant predictors of hip arthroplasty (p=<.001).

Conclusions

The incidence of hip dysplasia in EOS and AIS populations is higher than that of the general population. The rate of DDH was 3.9% and 1.8% for EOS and AIS, respectively. While the incidence of DDH is higher, associated anomalies of osteoarthritis, osteonecrosis, labral tears, and ankylosis appear to be a minimal risk for AIS and EOS patients with Hip Dysplasia.

Risk factors for predicting complications associated with growing rod surgery for early-onset scoliosis

OBJECTIVE

To identify risk factors for postoperative complications associated with growing rod surgery for early-onset scoliosis (EOS).

METHODS

A total of 55 consecutive patients underwent growing rod surgery for EOS were examined from database. Data included age at initial surgeries, sex, diagnosis, body mass index (BMI), duration of follow-up, initial and final measure of major curve, T2-5, T5-12, T10-L2, and T12-S1 kyphosis angles, levels and type of instrumentation, total number of surgeries, number of rods inserted, number of lengthenings, lengthening intervals and rod location were studied. Risk factors for postoperative complications were analyzed using binomial multiple logistic regression analysis.

RESULTS

Postoperative complications were associated with 37 of 272 procedures (14%) and affected 23 patients (42%). Complications included 25 implant-related failures (66%), 4 alignment complications (11%), 4 infections (11%), 1 neurological impairment (3%), 3 respiratory problems, 2 gastrointestinal problems, 1 urinary problem, and 1 dural tear. The most frequent implant-related failure was dislodged implant (76%) and 92% of the dislodgements occurred at the proximal foundation. Binomial multiple logistic regression analysis demonstrated that curve magnitude in last follow-up (OR: 1.042; P=0.036), duration between growing-rod lengthening procedures (OR: 1.121; P=0.003) and duration of follow-up (OR: 1.079; P=0.001) maintained its significance in predicting likelihood of postoperative complications.

CONCLUSION

The occurrence of postoperative complications in growing rod surgery for EOS is most likely multifactorial and is related to curve magnitude in last follow-up and duration between growing-rod lengthening procedures.

Growth guidance system for early-onset scoliosis: comparison of experimental and retrieval wear

STUDY DESIGN

Laboratory study conducted using an in vitro wear simulator with a growth guidance system. Analysis of variance performed to compare in vitro specimens (n = 6) with in vivo retrieval components (n = 5).

OBJECTIVE

To characterize the stainless steel, wear debris potential of a spinal growth guidance system by developing an in vitro model and validating tested implants with retrospectively obtained retrievals.

SUMMARY OF BACKGROUND DATA

Growth enabling, surgical treatments have been developed to provide fusionless options for patients with early-onset scoliosis. There exist few data regarding the wear debris associated with such spinal systems.

METHODS

In this study, we determined in vitro wear from the stainless steel components of the SHILLA™ Growth Guidance System. An analogue lumbar spine model was adapted from ISO 12189:2008 to assess the growth guidance system. In a multistation wear simulator, 6 assembled constructs were tested under displacement control for 5 million cycles (Mc) with diluted bovine serum, and the wear was measured gravimetrically at end of the test. The components were compared quantitatively for wear scar depth with retrieved growth guidance implants (n = 5), and qualitatively for wear, corrosion, and other surface damage.

RESULTS

The average total wear rate over 5 Mc was 0.39 ± 0.13 mm/Mc (3.12 ± 1.01 mg/Mc) with an average particle size of 1.3 μm in equivalent circular diameter. Prominent wear scars were noticed on both the tested and retrieved specimens with no statistical difference in the wear scar depths of the tested and retrieved components when set and multiaxial screws when compared collectively.

CONCLUSION

An in vitro wear analysis for a spinal growth guidance system was conducted using a novel protocol and validated against retrieved implants. This is the first study establishing a baseline value for the wear of "growth enabling" devices for the treatment of early-onset scoliosis.

Scoliosis in pediatric patients: comorbid disorders and screening

Scoliosis is one of the most commonly encountered pediatric spinal deformities. Knowledge of comorbid disorders associated with scoliosis is required in order to rule out other serious conditions. A thorough knowledge of the clinical scenarios associated with each of these disorders will help guide the pediatric practitioner in their work-up of associated conditions and possible further referrals. The aim of this review is to discuss the comorbidities associated with scoliosis and review appropriate screening tools aiding diagnosis.

Intraspinal anomalies in infantile idiopathic scoliosis: prevalence and role of magnetic resonance imaging

STUDY DESIGN

Retrospective case series of magnetic resonance imaging (MRI) findings in patients with presumed infantile idiopathic scoliosis (IIS).

OBJECTIVE

To identify the prevalence of intraspinal anomalies in patients with presumed IIS at a single, large volume institution and further define the role for a screening MRI.

SUMMARY OF BACKGROUND DATA

Idiopathic scoliosis in patients less than 10 years of age has been shown to carry a higher prevalence of concordant intraspinal anomalies, up to 20%, in juveniles, when compared to the adolescent age group. Few studies exist assessing the prevalence of intraspinal anomalies in the IIS patient population. Dobbs et al (2002) reported a 21.7% prevalence of neural axis abnormalities in 46 patients with presumed IIS across 3 combined spinal deformity clinics and recommended a screening MRI for all IIS patients with a curve >20 degrees.

METHODS

A retrospective review of the medical records of 54 patients at a single institution with a presumed diagnosis of IIS was performed. All patients satisfied the strict inclusion criteria of: curve > or =20 degrees, age <36 months at diagnosis, normal neurologic examination (i.e., normal tone, motor strength, reflexes, etc.), absence of any concomitant syndromes or congenital anomalies, and an MRI of the spine from skull to coccyx.

RESULTS

MRI revealed a neural axis abnormality in 7 (13%) of 54 patients who underwent an MRI. In this subset of 7 patients, 5 (71.4%) required neurosurgical intervention. Tethered cord requiring surgical release was identified in 3 patients, Chiari malformation requiring surgical decompression was found in 2 patients, and a small nonoperative syrinx was found in 2 patients.

CONCLUSION

This study represents the largest evaluation of intraspinal anomalies in IIS to date. Our patient population exhibited a smaller percentage (13%) of neural axis abnormalities than previously reported. On the basis of these findings, the close observation may be a reasonable alternative to an immediate screening MRI in patients presenting with presumed IIS and a curve >20 degrees.

Congenital scoliosis in monozygotic twins: case report and review of possible factors contributing to its development

BACKGROUND

The exact etiology of congenital scoliosis remains unknown as yet. It seems that its development may be influenced by both genetic predisposition and environmental factors, at varying degrees. International bibliography features few cases of monozygotic twins with congenital scoliosis. The aim of this study is to report a case in monozygotic twins and review the literature relating to the description of similar cases as well as the pathophysiological mechanism involved in its development.

METHODS

Clinical examination and simple X-rays revealed scoliosis of differing degrees and types in male monozygotic twins with moderate mental retardation and dyslalia.

RESULTS

Congenital scoliosis identified in both twins. In the first, this was manifested as left thoracic scoliosis, with Cobb angle of 34 degrees while in the second as left thoracolumbar scoliosis with Cobb angle of 10 degrees. Both were found to suffer from incarcerated hemivertebrae.

CONCLUSION

According to both its clinical identification and severity and to its course, not only the genetic but the environmental factors seem to play a leading role in the appearance of the condition.

DECISION MAKING IN PEDIATRIC SPINAL DEFORMITY

OBJECTIVE

To review the concepts involved in the decision-making process for management of pediatric patients with spinal deformity.

METHODS

The literature was reviewed in reference to pediatric deformity evaluation and management.

RESULTS

Pediatric spinal deformity includes a broad range of disorders with differing causes, natural histories, and treatments. Appropriate categorization of pediatric deformities is an important first step in the clinical decision-making process. An understanding of both nonoperative and operative treatment modalities and their indications is requisite to providing treatment for pediatric patients with spinal deformity. The primary nonoperative treatment modalities include bracing and casting, and the primary operative treatments include nonfusion instrumentation and fusion with or without instrumentation. In this article, we provide a review of pediatric spinal deformity classification and an overview of general treatment principles.

CONCLUSION

The decision-making process in pediatric deformity begins with appropriate diagnosis and classification of the deformity. Treatment decisions, both nonoperative and operative, are often predicated on the basis of the age of the patient and the natural history of the disorder.