Correlation between compliance and brace treatment in juvenile and adolescent idiopathic scoliosis: SOSORT 2014 award winner

Background

Over the last years, evidence has accumulated in support of bracing as an effective treatment option in patients with idiopathic scoliosis. Yet, little information is available on the impact of compliance on the outcome of conservative treatment in scoliotic subjects. The aim of the present study was to prospectively evaluate the association between compliance to brace treatment and the progression of scoliotic curve in patients with idiopathic adolescent (AIS) or juvenile scoliosis (JIS).

Methods

Among 1.424 patients treated for idiopathic scoliosis, 645 were eligible for inclusion criteria. Three outcomes were distinguished in agreement with the SRS criteria: curve correction, curve stabilization and curve progression. Brace wearing was assessed by one orthopaedic surgeon (LA) and scored on a standardized form. Compliance to treatment was categorized as complete (brace worn as prescribed), incomplete A (brace removed for 1 month), incomplete B (brace removed for 2 months), incomplete C (brace removed during school hours), and incomplete D (brace worn overnight only). Chi square test, T test or ANOVA and ANOVA for repeated measures tests were used as statistical tests.

Results

The results from our study showed that at follow-up the compliance was: Complete 61.1%; Incomplete A 5.2%; Incomplete B 10.7%; Incomplete C 14.2%; Incomplete D 8.8%. Curve correction was accomplished in 301/319 of Complete, 19/27 Incomplete A, 25/56 Incomplete B, 52/74 Incomplete C, 27/46 Incomplete D. Cobb mean value was 29.8 ± 7.5 SD at beginning and 17.1 ± 10.9 SD at follow-up. Both Cobb and Perdriolle degree amelioration was significantly higher in patients with complete compliance over all other groups, both in juvenile, both in adolescent scoliosis. In the intention-to-treat analysis, the rate of surgical treatment was 2.1% among patients with definite outcome and 12.1% among those with drop-out. Treatment compliance showed significant interactions with time.

Conclusion

Curve progression and referral to surgery are lower in patients with high brace compliance. Bracing discontinuation up to 1 month does not impact on the treatment outcome. Conversely, wearing the brace only overnight is associated with a high rate of curve progression.

Intraspinal canal rod migration causing late-onset paraparesis 8 years after scoliosis surgery

INTRODUCTION

Complete intraspinal canal rod migration with posterior bone reconstitution has never been described in the adolescent idiopathic scoliosis (AIS) population. We present an unusual but significant delayed neurological complication after spinal instrumentation surgery.

CASE REPORT

A 24-year-old woman presented with lower limb weakness (ASIA D) 8 years after posterior instrumentation from T2 to L4 for AIS. CT scan and MRI demonstrated intra-canal rod migration with complete laminar reconstitution. The C-reactive protein was slightly elevated (fluctuated between 10 and 20 mg/l). Radiographs showed the convex rod had entered the spinal canal. The patient was taken into the operating room for thoracic spinal decompression and removal of the convex rod. This Cotrel-Dubousset rod, which had been placed on the convexity of the thoracic curve had completely entered the canal from T5 to T10 and was totally covered by bone with the eroded laminae entirely healed and closed. There was no pseudarthrosis. Intra-operatively, the fusion mass was opened along the whole length of this rod and the rod carefully removed and the spinal cord decompressed. The bacteriological cultures returned positive for Propionibacterium acnes. The patient recovered fully within 2 months post-operatively.

CONCLUSION

We opine that the progressive laminar erosion with intra-canal rod migration resulted from mechanical and infectious-related factors. The very low virulence of the strain of Propionibacterium acnes is probably involved in this particular presentation where the rod was trapped in the canal, owing to the quite extensive laminar reconstitution.

The progression of lumbar curves in adolescent Lenke 1 scoliosis and the distal adding-on phenomenon

INTRODUCTION

The postoperative deterioration of the curve below spinal fusion instrumentation resulting in a distal adding-on (AO) phenomenon in idiopathic adolescent scoliosis (IAS) frequently requires surgical revision with disappointing secondary clinical results.

HYPOTHESIS

Analysis of AP (coronal) range of motion (cROM) and lateral (sagittal) range of motion (sROM) on dynamic (side-bending, flexion, extension) X-rays to determine the choice of the lowest instrumented vertebra (LIV) can help reduce distal adding-on. The goal of this study was to study the postoperative progression of the lumbar curve in Lenke 1 scoliosis operated on with a LIV based on dynamic X-ray results.

MATERIALS AND METHODS

Right-sided Lenke 1 IAS that was treated surgically by posterior arthrodesis alone with a follow-up of at least 2 years was included in the study. The following radiographic parameters were evaluated: the Cobb angles of the curves, reducibility of the curves, the apex of the scoliosis, the central sacral vertical line, the stable vertebra (SV), the neutral vertebra (NV), the distances between the CSVL and the centroids of the LIV and of the first vertebra below instrumentation, as well as the tilt of the superior endplates. sROM and cROM were determined on dynamic X-rays.

RESULTS

Fifty IAS were evaluated/185 files. Only three cases fulfilled the criteria for AO including two that were secondary to peri- or postoperative complications. The lumbar curve presented with a loss of correction of 0.9° at one year and 1.14° at the final follow-up. None of the parameters studied were correlated to the deterioration of the lumbar curve.

DISCUSSION

The choice of the LIV has been shown to influence the deterioration of the lumbar curve and the development of AO. The choice of the LIV based on an analysis of AP (coronal) and lateral (sagittal) range of motion seems to prevent the development of AO.

LEVEL OF EVIDENCE

4, retrospective study.

Evaluation of bone mineral status in adolescent idiopathic scoliosis

Background

Several reports have suggested low bone mineral density (BMD) in patients with adolescent idiopathic scoliosis (AIS). We determined bone mineral status in patients with AIS to evaluate the effect of brace treatment on BMD.

Methods

BMD was measured in 46 patients (mean age, 17.8 ± 4.9 years) with AIS (17 with brace and 29 without brace) by dual-energy X-ray absorptiometry scan and compared the results to an age-matched (mean age, 16.6 ± 3.9 years) control group (n = 54).

Results

The AIS group had significantly lower bone mass at the lumbar spine (Z-score, -1.500 vs. -0.832) and hip (Z-score, -1.221 vs. -0.754) except at the femoral neck. No difference in BMD was found between patients with AIS who used a brace and those who did not.

Conclusions

The results confirmed that BMD was low in AIS patients and it was not affected by brace treatment.

Increased Body Mass Index Negatively Affects Patient Satisfaction After a Posterior Fusion and Instrumentation for Adolescent Idiopathic Scoliosis

STUDY DESIGN

Retrospective.

SUMMARY OF BACKGROUND DATA

Previous studies have reported the correlation of body mass index (BMI) with non-spine surgical outcomes; however, only a few reviewed the correlation of BMI to outcomes after spine surgery.

OBJECTIVES

To review the influence of preoperative BMI on the follow-up clinical and functional outcomes after posterior-only fusion (PSF) and instrumentation for adolescent idiopathic scoliosis in a larger patient cohort.

METHODS

Retrospective review of a consecutive series of patients treated with PSF for adolescent idiopathic scoliosis from 2002 to 2009 at a single institution. There were 3 categories: underweight (UW), normal weight (NML), and overweight (OW). Percent correction of the major curve was collected at 2 years postoperatively and patient outcome scores were analyzed preoperatively and at 2 years postoperatively. Differences between groups were analyzed using analysis of variance, with p < .05.

RESULTS

A total of 459 patients at an average age of 15.0 years (range, 10.0-21.3 years) treated with PSF instrumentation were included. At 2 years, all groups achieved and maintained equal percent correction with no differences between groups. Regarding preoperative Scoliosis Research Society (SRS) outcome scores, OW patients reported more pain than NML (p = .002) and UW patients (p < .001) despite less reported activity than for the NML (p = .033) and UW groups (p = .005). The total SRS score was also lower in the OW patients compared with NML (p = .009) and UW patients (p = .002). At 2 years, the OW group reported more pain than the UW (p = .031) and NML groups (p = .018), lower mental scores (p = .011) and lower SRS total scores (p = .005) than the NML group.

CONCLUSIONS

At follow-up, preoperative overweight adolescents reported more pain and lower mental, activity, and appearance domain scores after surgery than UW and NML patients despite equal percent curve correction. This information may help the surgeon with preoperative counseling of OW patients by stressing that their own assessment of outcome is influenced by BMI, which may help promote a healthy weight management program in this patient group.

Intra- and Interobserver Reliability of the Cobb Angle-Vertebral Rotation Angle-Spinous Process Angle for Adolescent Idiopathic Scoliosis

STUDY DESIGN

A reliability analysis of Cobb angle, vertebral rotation (VR), and spinous process angle (SPA) measurements in adolescent idiopathic scoliosis.

OBJECTIVE

To determine the intra- and interobserver reliability of semi-automated digital radiograph measurements.

SUMMARY OF BACKGROUND DATA

Cobb angle measurements on posteroanterior radiographs are commonly used to determine the severity of scoliosis. Vertebral rotation helps assess scoliosis 3-dimensionally and has a role in predicting curve progression. Recent studies have shown that the spinous process angle is a useful parameter in assessing scoliosis when using ultrasound imaging. Because the reliability of SPA measurements on radiographs has yet to be determined, it is important to compare the reliability of these 3 parameters (Cobb angle, VR, and SPA) using a computer assisted semi-automated method.

METHODS

Sixty posteroanterior radiographs of patients with adolescent idiopathic scoliosis were obtained and measured twice by 3 observers who were blinded to their previous measurements, using an in-house developed program. Measurements were obtained using a semi-automated method to minimize variability resulting from observer reliability. The intra- and interobserver reliabilities were analyzed using intra-class correlation coefficients (ICCs) as well as Bland-Altman's bias and limits of agreement.

RESULTS

Over 350 (intra) and 90 (inter) sets of curves with an average Cobb angle of 26° ± 9° (range, 10° to 44°) were compared for each parameter. Intra-observer reliabilities for each parameter were excellent (ICC_[2,1], .82; 1.00), with mean absolute differences under 3° between most measurements. Interobserver reliability (ICC_[2,1], .72; .95) was mostly good to excellent, with mean absolute differences ranging from 2.0° to 5.6°.

CONCLUSIONS

Both the intra- and interobserver assessment of the Cobb, VR, and SPA from the semi-automated measurements had clinically acceptable reliability ranges and may be considered for clinical implementation. Additional studies will be conducted to determine the accuracy and sensitivity to change of these scoliosis severity measurements.

The influence of thoracolumbosacral orthoses on standing balance in patients with adolescent idiopathic scoliosis: a pilot study

BACKGROUND AND AIM

The objective of this study was to assess the effect of thoracolumbosacral orthoses (TLSOs) on antero-posterior (AP) sway, medio-lateral (ML) sway and displacement of the center of pressure (COP) during a longitudinal study in patients with adolescent idiopathic scoliosis (AIS).

METHODS

Eight females aged between 12 and 14.5 years participated in this study. Evaluations were performed prior to the TLSO intervention as a baseline condition, after 1 month, and after 4 months of orthosis use by assessing balance when standing statically on different surfaces.

RESULTS

When standing on both lower limbs on a solid surface there were significant differences in ML sway with the eyes both open and closed, and also in A/P sway but only when standing on a solid surface with the eyes open and also when standing on a foam surface with the eyes closed with TLSO use. When standing on the dominant leg, ML sway significantly improved, but AP sway only improved with a foam base surface with the eyes open.

CONCLUSION

This study demonstrated positive effects of wearing a TLSO in improving quiet standing balance and standing on the dominant lower extremity in subjects with AIS after 4 months of brace use. Implications for Rehabilitation Due to a change in body shape such as that caused by scoliosis, human posture changes and spinal deformities affect the position of the center of support, and thus balance ability may change. AIS subjects have poor standing stability compared to a healthy matched control group. Brace wearing had positive effect in improving quiet standing balance and standing on the dominant lower extremity in subjects with AIS undergoing brace treatment after 4 months of TLSO use.

Improving the measurement of health-related quality of life in adolescent with idiopathic scoliosis: the SRS-7, a Rasch-developed short form of the SRS-22 questionnaire

Scoliosis Research Society-22 (SRS-22) questionnaire was developed to evaluate health-related quality of life (HRQL) in adolescent idiopathic scoliosis (AIS) patients. Rasch analysis (RA) is a statistical procedure which turns questionnaire ordinal scores into interval measures. Measures from Rasch-compatible questionnaires can be used, similar to body temperature or blood pressure, to quantify disease severity progression and treatment efficacy. Purpose of the current work is to present Rasch analysis (RA) of the SRS-22 questionnaire and to develop an SRS-22 Rasch-approved short form. 300 SRS-22 were randomly collected from 2447 consecutive IS adolescents at their first evaluation (229 females; 13.9 ± 1.9 years; 26.9 ± 14.7 Cobb°) in a scoliosis outpatient clinic. RA showed both disordered thresholds and overall misfit of the SRS-22. Sixteen items were re-scored and two misfitting items (6 and 14) removed to obtain a Rasch-compatible questionnaire. Participants HRQL measured too high with the rearranged questionnaire, indicating a severe SRS-22 ceiling effect. RA also highlighted SRS-22 multidimensionality, with pain/function not merging with self-image/mental health items. Item 3 showed differential item functioning (DIF) for both curve and hump amplitude. A 7-item questionnaire (SRS-7) was prepared by selecting single items from the original SRS-22. SRS-7 showed fit to the model, unidimensionality and no DIF. Compared with the SRS-22, the short form scale shows better targeting of the participants' population. RA shows that SRS-22 has poor clinimetric properties; moreover, when used with AIS at first evaluation, SRS-22 is affected by a severe ceiling effect. SRS-7, an SRS-22 7-item short form questionnaire, provides an HRQL interval measure better tailored to these participants.

Sagittal Cervical Alignment in Adolescent Idiopathic Scoliosis

STUDY DESIGN

Retrospective case series of surgically treated adolescent scoliosis patients.

OBJECTIVES

To assess the radiographic changes of cervical kyphosis and identify the possible factors affecting postoperative sagittal cervical kyphosis in surgically treated patients with adolescent idiopathic scoliosis.

SUMMARY OF BACKGROUND DATA

Cervical kyphosis is a well-recognized phenomenon in patients with adolescent idiopathic scoliosis. Despite recent reports, the prevalence, radiographic changes, and possible factors affecting postoperative sagittal cervical kyphosis are controversial.

MATERIALS AND METHODS

A retrospective review of a single-center database was performed on 133 consecutive patients with adolescent idiopathic scoliosis treated with long instrumented (more than 5 levels) spine fusion (minimum, 2 years; mean, 3.3 years; range, 2 to 5.5 years). A total of 89 patients met all of the inclusion criteria. Preoperative and postoperative radiographic measurements and patient demographics were investigated.

RESULTS

Postoperative cervical kyphosis was observed in 46 patients. Cobb angle decreased from 48.1° ± 13.1° to 15.4° ± 11.1° at the final follow-up. Cervical kyphosis significantly decreased from 5.5° ± 8.9° preoperatively to -1.5° ± 8.9° at the final follow-up. No difference was observed for T2-T5, T5-T12, lumbar lordosis, sacral slope, pelvic incidence, pelvic tilt, and sagittal vertical axis during the follow-up. Notably, T2 sagittal tilt was significantly increased from preoperatively to the final follow-up. Pearson correlation coefficient test showed a strong correlation between postoperative cervical lordosis and T2 sagittal tilt (r = 0.73; p < .001).

CONCLUSIONS

Despite the significant increase of cervical lordosis, 85% of patients still have a kyphotic or less lordotic cervical spine. The strong positive association between cervical lordosis and T2 sagittal tilt suggests that the sagittal cervical alignment of adolescent idiopathic scoliosis patients is closely related to the global sagittal spine balance rather than thoracic kyphosis.

Differences in early sagittal plane alignment between thoracic and lumbar adolescent idiopathic scoliosis

BACKGROUND CONTEXT

It has previously been shown that rotational stability of spinal segments is reduced by posteriorly directed shear loads that are the result of gravity and muscle tone. Posterior shear loads act on those segments of the spine that are posteriorly inclined, as determined by each individual's inherited sagittal spinal profile. Accordingly, it can be inferred that certain sagittal spinal profiles are more prone to develop a rotational deformity that may lead to idiopathic scoliosis; and lumbar scoliosis, on one end of the spectrum, develops from a different sagittal spinal profile than thoracic scoliosis on the other end.

PURPOSE

To examine the role of sagittal spinopelvic alignment in the etiopathogenesis of different types of idiopathic scoliosis.

STUDY DESIGN/SETTING

Multicenter retrospective analysis of lateral radiographs of patients with small thoracic and lumbar adolescent idiopathic scoliotic curves.

PATIENTS SAMPLE

We included 192 adolescent idiopathic scoliosis patients with either a thoracic (n=128) or lumbar (n=64) structural curve with a Cobb angle of less than 20° were studied. Children with other spinal pathology or with more severe idiopathic scoliosis were excluded, because this disturbs their original sagittal profile. Subjects who underwent scoliosis screening and had a normal spine were included in the control cohort (n=95).

OUTCOME MEASURES

Thoracic kyphosis, lumbar lordosis, T9 sagittal offset, C7 and T4 sagittal plumb lines, pelvic incidence, pelvic tilt, and sacral slope, as well as parameters describing orientation in space of each individual vertebra between C7 and L5 and length of the posteriorly inclined segment.

METHODS

On standardized lateral radiographs of the spine, a systematic, semi-automatic measurement of the different sagittal spinopelvic parameters was performed for each subject using in-house developed computer software.

RESULTS

Early thoracic scoliosis showed a significantly different sagittal plane from lumbar scoliosis. Furthermore, both scoliotic curve patterns were different from controls, but in a different sense. Thoracic kyphosis was significantly decreased in thoracic scoliosis compared with both lumbar scoliosis patients and controls. For thoracic scoliosis, a significantly longer posteriorly inclined segment, and steeper posterior inclination of C7-T8 was observed compared with both lumbar scoliosis and controls. In lumbar scoliosis, the posteriorly inclined segment was shorter and located lower in the spine, and T12-L4 was more posteriorly inclined than in the thoracic group. The lumbar scoliosis cohort had a posteriorly inclined segment of the same length as controls, but T12-L2 showed steeper posterior inclination. Lumbar lordosis, pelvic incidence, pelvic tilt, and sacral slope, however, were similar for the two scoliotic subgroups as well as the controls.

CONCLUSIONS

This study demonstrates that even at an early stage in the condition, the sagittal profile of thoracic adolescent idiopathic scoliosis differs significantly from lumbar scoliosis, and both types of scoliosis differ from controls, but in different aspects. This supports the theory that differences in underlying sagittal profile play a role in the development of different types of idiopathic scoliosis.

Revisiting scoliosis in the KNM-WT 15000 Homo erectus skeleton

Owing to its completeness, the 1.5 million year old Nariokotome boy skeleton KNM-WT 15000 is central for understanding the skeletal biology of Homo erectus. Nevertheless, since the reported asymmetries and distortions of Nariokotome boy's axial skeleton suggest adolescent idiopathic scoliosis, possibly associated with congenital skeletal dysplasia, it is questionable whether it still can be used as a reference for H. erectus. Recently, however, the presence of skeletal dysplasia has been refuted. Here, we present a morphological and morphometric reanalysis of the assertion of idiopathic scoliosis. We demonstrate that unarticulated vertebral columns of non-scoliotic and scoliotic individuals can be distinguished based on the lateral deviation of the spinous process, lateral and sagittal wedging, vertebral body torsion, pedicle thickness asymmetry, and asymmetry of superior and inferior articular facet areas. A principal component analysis of the overall asymmetry of all seven vertebral shape variables groups KNM-WT 15000 within non-scoliotic modern humans. There is, however, an anomaly of vertebrae T1-T2 that is compatible with a short left convex curve at the uppermost thoracic region, possibly due to injury or local growth dysbalance. Asymmetries of the facet joints L3-L5 suggest a local right convex curve in the lower lumbar region that probably resulted from juvenile traumatic disc herniation. This pattern is incompatible with adolescent idiopathic scoliosis or other types of scoliosis, including congenital, neuromuscular or syndromic scoliosis. It is, however, consistent with a recent reanalysis of the rib cage that did not reveal any asymmetry. Except for these possibly trauma-related anomalies, the Nariokotome boy fossil therefore seems to belong to a normal H. erectus youth without evidence for adolescent idiopathic scoliosis or other severe pathologies of the axial skeleton.

[Severe idiopathic scoliosis. Does the approach and the instruments used modify the results?]

OBJECTIVE

The aim of this work is to evaluate and compare the radiographic results and complications of the surgical treatment of adolescents with idiopathic scoliosis greater than 75 degrees, using a double approach (DA) or an isolated posterior approach with hybrid instruments (posterior hybrid [PH]), or with «all-pedicle screws» (posterior screws [PS]).

MATERIAL AND METHOD

A retrospective review was performed on 69 patients with idiopathic scoliosis greater than 75°, with a follow-up of more than 2 years, to analyze the flexibility of the curves, the correction obtained, and the complications depending on the type of surgery. The Kruskal-Wallis test for non-parametric variables was used for the statistical analysis.

RESULTS

There were no statistically significant differences between the 3 patient groups in the pre-surgical Cobb angle values (DA=89°, PH=83°, PS=83°), in the immediate post-surgical (DA=34°, PH=33°, PS=30°), nor at the end of follow-up (DA=36°, PH=36°, PS=33°) (P>.05). The percentage correction (DA=60%, PH=57%, PS=60%) was similar between groups (P>.05). The percentage of complications associated with the procedure was 20.8% in DA, 10% in PH and 20% in PS. Two patients in the PS group showed changes, with no neurological lesions, in the spinal cord monitoring, and one patient in the same group suffered a delayed and transient incomplete lesion.

DISCUSSION AND CONCLUSIONS

No significant differences were observed in the correction of severe idiopathic scoliosis between patients operated using the double or isolated posterior approach, regardless of the type of instrumentation used.

Quantification of the spatial strain distribution of scoliosis using a thin-plate spline method

The objective of this study was to quantify the three-dimensional spatial strain distribution of a scoliotic spine by nonhomogeneous transformation without using a statistically averaged reference spine. The shape of the scoliotic spine was determined from computed tomography images from a female patient with adolescent idiopathic scoliosis. The shape of the scoliotic spine was enclosed in a rectangular grid, and symmetrized using a thin-plate spline method according to the node positions of the grid. The node positions of the grid were determined by numerical optimization to satisfy symmetry. The obtained symmetric spinal shape was enclosed within a new rectangular grid and distorted back to the original scoliotic shape using a thin-plate spline method. The distorted grid was compared to the rectangular grid that surrounded the symmetrical spine. Cobb's angle was reduced from 35° in the scoliotic spine to 7° in the symmetrized spine, and the scoliotic shape was almost fully symmetrized. The scoliotic spine showed a complex Green-Lagrange strain distribution in three dimensions. The vertical and transverse compressive/tensile strains in the frontal plane were consistent with the major scoliotic deformation. The compressive, tensile and shear strains on the convex side of the apical vertebra were opposite to those on the concave side. These results indicate that the proposed method can be used to quantify the three-dimensional spatial strain distribution of a scoliotic spine, and may be useful in quantifying the deformity of scoliosis.

The Use of Finite Element Models to Assist Understanding and Treatment For Scoliosis: A Review Paper

INTRODUCTION

Scoliosis is a complex spinal deformity whose etiology is still unknown, and its treatment presents many challenges. Finite element modeling (FEM) is one of the analytical techniques that has been used to elucidate the mechanism of scoliosis and the effects of various treatments.

METHODS

A literature review on the application of FEM in scoliosis evaluation and treatment has been undertaken. A literature search was performed in each of three major electronic databases (Google Scholar, Web of Science, and Ovid) using the key words "scoliosis" and "finite element methods/model". Articles using FEM and having a potential impact on clinical practice were included.

RESULTS

A total of 132 abstracts were retrieved. The query returned 105 articles in which the abstracts appeared to correspond to this review's focus, and 85 papers were retained. The current state of the art of FEM related to the biomechanical analysis of scoliosis is discussed in 4 sections: the etiology of adolescent idiopathic scoliosis, brace treatment, instrumentation treatment, and sensitivity studies of FEM. The limitations of FEM and suggested future work are also discussed.

Understanding the Basis of Genetic Studies: Adolescent Idiopathic Scoliosis as an Example

STUDY DESIGN

A review of the general concepts of genetics studies with specific reference to adolescent idiopathic scoliosis (AIS).

OBJECTIVES

To equip the average spine surgeon with the vocabulary and understanding needed to understand the genetics of scoliosis and the approaches used to identify risk genes.

SUMMARY OF BACKGROUND DATA

Adolescent idiopathic scoliosis is a multifactorial disease. Increasing evidence from families and monozygotic twins suggests the involvement of genetic factors. An estimation of heritability also indicates a strong influence of genetics on the disease. Increasing focus has been placed on identifying genes and genetic variants associated with AIS.

REVIEW

This is a review of genes and genetic variations, the phenotype definition of AIS in genetics studies, concepts and approaches to identifying associated genes, and the evaluation of results. Different types of genetic variations are present in the genome. These variations may modulate the expression or function of protein products, which in turn alter individuals' susceptibility to disease. Identifying the variants related to AIS requires an objective and clearly defined phenotype, among which the Cobb angle is commonly used. The phenotype helps classify subjects into cases and controls. By selecting candidate genes of growth factors and hormonal receptors, which are speculated to be involved in the mechanism of disease, the variants within these genes were compared between cases and controls to identify any differences. Another approach was to use large families and inspect the co-segregation of variants and phenotypes. Recently, arrays covering the variants of the whole genome were developed and assist in high-throughput screening for associated genes.

CONCLUSIONS

Genetic factors have an important role in AIS. Deciphering the genes and genetic variants associated with AIS can improve our understanding of the mechanisms of the disease, as well as assist in designing treatment methods and preventive measures.

The current status of bracing for patients with adolescent idiopathic scoliosis

Adolescent idiopathic scoliosis affects about 3% of children. Non-operative measures are aimed at altering the natural history to maintain the size of the curve below 40° at skeletal maturity. The application of braces to treat spinal deformity pre-dates the era of evidence-based medicine, and there is a paucity of irrefutable prospective evidence in the literature to support their use and their effectiveness has been questioned. This review considers this evidence. The weight of the evidence is in favour of bracing over observation. The most recent literature has moved away from addressing this question, and instead focuses on developments in the design of braces and ways to improve compliance.

Volumetric changes in cerebellar regions in adolescent idiopathic scoliosis compared with healthy controls

BACKGROUND CONTEXT

Adolescent idiopathic scoliosis (AIS) is a three-dimensional spinal deformation that affects adolescents, especially girls. The etiopathogenesis of this disease remains uncertain, and studies have been carried out to understand its cause and related organs. Previous studies suggest that AIS is probably related to the cerebellum dysfunction, which could also be related to the abnormality in morphology of the cerebellum.

PURPOSE

The purpose of the study is to investigate the relationship between AIS and the volume and morphology of cerebellum.

STUDY DESIGN/SETTING

The study design of the cerebellum segmentation and volume quantification involved the following four steps: whole-brain normalization, cerebellum isolation, mapping with the statistical cerebellum template, and cerebellum regional volume correction.

PATIENT SAMPLE

In particular, high-resolution T1-weighted magnetic resonance images of 50 AIS patients with the right-thoracic curves (ie, Cobb angle ≥20°) and 40 age-matched normal controls were acquired. The exclusion criteria included history of head injury, back injury, severe headache, weakness or numbness in any limbs, urinary incontinence, nocturnal enuresis, and any space-occupying lesion found on magnetic resonance (MR) images.

OUTCOME MEASURES

The AIS subjects were all with moderate-to-severe curves (ie, Cobb angle ≥20°) (9 moderate and 41 severe; mean Cobb angle 48.7°, range 20°-90°).

METHODS

The cerebellum was parcellated to 28 regions by mapping with a well-recognized probabilistic MR cerebellum atlas. Student t test of each cerebellar region and the correction for multiple comparisons were performed.

RESULTS

The volumes of four regions, namely right VIIIa, right VIIIb, left X, and right X, were significantly increased by approximately 7.43% to 8.25% in the AIS compared with the control group. Statistically, the results suggested that the cerebellar volume in AIS patients was larger compared with normal controls in the cerebellum regions of prepyramidal-prebiventer and intrabiventer fissures, intrabiventer and secondary fissures, and floccular-nodular (X)-posterolateral fissure to the inferior hemispheric margin.

CONCLUSIONS

The functions of the affected regions involve motor control, somatosensory, working memory, language, and response to visual stimulation. We conclude that the volume difference could be compensatory consequences in the central nervous system because of the persistent effort in AIS patients to maintain the body balance given the asymmetric spine.

Reliability of assessing the coronal curvature of children with scoliosis by using ultrasound images

PURPOSE

To investigate the intra- and inter-observer reliability of the coronal curvature asymmetry of children with adolescent idiopathic scoliosis (AIS) using the center of lamina (COL) method on ultrasound (US) images.

METHODS

A cadaver spinal column phantom which was manipulated to present 30 scoliotic curves of varying severity of scoliotic deformities was scanned using both the US and laser scanner (LS) systems. Three observers of varying experience and skill measured the coronal curvature using the Cobb method on the LS images and the COL method on the US images. All of the measurements were performed twice, with a 1-week interval to reduce memory bias. The intra-class correlation coefficient (ICC), the mean absolute differences (MAD), and the error index (EI) were calculated to determine the agreement on selecting the end vertebrae. In addition, five AIS subjects were scanned using the US system. One observer measured the coronal curvature on the US images twice, and the measurements were compared with the Cobb angle reported in the clinical records.

RESULTS

In the phantom study, the COL method showed high intra- and inter-observer reliabilities, with all ICC values >0.88. The maximum MAD of the COL measurements between different sessions among all observers was <4.1°. The EI values of the US method had similar end-vertebra selections as the LS method. The results of the pilot study showed a high intra-reliability for the US measurements. The measured difference between the Cobb and COL methods was 0.7° ± 0.5°.

CONCLUSIONS

The COL method using US images appears to be a very reliable method for measuring the coronal curvature in AIS without the need to expose the patient to radiation.

Airport metal detector activation is rare after posterior spinal fusion in children with scoliosis

PURPOSE

Since the September 11, 2001 terrorist attacks on the World Trade Center in New York City, travel security has become an ever-increasing priority in the United States. Frequent parent and patient inquiry and recent literature reports have generated interest in the impact of heightened security measures on patients with orthopaedic implants, and have indicated increasing rates of metal detector triggering. There are no reports to date, however, evaluating children and adolescents who have undergone posterior spinal fusion for scoliosis, so responses to patient and parent inquiries are not data-driven. The purpose of this study is to determine the frequency of airport metal detector triggering by patients who have had posterior-only spinal fusion and to characterise any potential predictors of metal detector activation.

METHODS

A cross-sectional study was performed by interviewing 90 patients who underwent posterior-only spinal fusion for a diagnosis of juvenile or adolescent idiopathic scoliosis and have travelled by air in the past year. Demographic, clinical and surgical instrumentation data were collected and evaluated, along with patients' reports of airport metal detector triggering and subsequent screening procedures.

RESULTS

Five patients with stainless steel instrumentation (5.6 % of the cohort) triggered an airport walkthrough metal detector, and an additional five patients who did not trigger an airport detector triggered a handheld detector at a different venue. All patients who triggered an airport metal detector had stainless steel instrumentation implanted prior to 2008, and no patient with titanium instrumentation triggered any detector in any venue. All trigger events required subsequent screening procedures, even when an implant card was presented.

CONCLUSIONS

In this cohort of children and adolescents with posterior spinal instrumentation, airport walkthrough metal detector triggering was a rare event. Therefore, we advise patients and families with planned posterior scoliosis fusions using titanium instrumentation that airport detection risk is essentially non-existent, and only rare for those with planned stainless steel instrumentation. We no longer issue implant cards postoperatively, as these did not prevent further screening procedures in this cohort.

LEVEL OF EVIDENCE

Prognostic level 2.

STUDY DESIGN

cross-sectional.

The effects of backpack load and carrying method on the balance of adolescent idiopathic scoliosis subjects

BACKGROUND CONTEXT

Concerns have been raised about the effect of backpack carrying on adolescent balance. For adolescent idiopathic scoliosis (AIS) subjects, the effect of backpack carrying method on their balance has not been determined. Our aim is to examine the effects of backpack load and carrying method on AIS subjects' balance.

STUDY DESIGN/SETTING

Paired sample matched for age and sex.

PATIENT SAMPLE

Twelve healthy adolescents matched for age and sex with 14 adolescents with mild AIS participated in this study.

OUTCOME MEASURES

A test battery including clinical examination, radiological assessment, and stabilometric measurements of the postural sways in the upright standing posture were conducted.

METHODS

Center of pressure excursions of our subjects were recorded with a stabilometric platform during the upright standing posture without a backpack and while carrying a backpack symmetrically and asymmetrically on each shoulder. For each carrying method, the backpack is loaded at 10% and 15% of body weight (BW).

RESULTS

Our results indicated that postural sways increased with increasing backpack load. These postural sways were observed when normal adolescents carried a backpack loaded with 15% BW load, whereas, for age- and sex-matched AIS subjects, these postural responses were observed for the 10% BW load. The symmetrical backpack carrying induced better balance compared with the asymmetrical one. Asymmetrical carrying on the convex side of the scoliotic curve affects AIS subjects' balance more than carrying it on the concave side.

CONCLUSIONS

Load carriage of 10% BW seems to alter AIS subjects' balance. Asymmetrical carrying should be avoided especially on the convex side of the scoliotic curve because it causes balance impairments that may increase spinal pain.

Artificial neural networks assessing adolescent idiopathic scoliosis: comparison with Lenke classification

BACKGROUND CONTEXT

Variability in classifying and selecting levels of fusion in adolescent idiopathic scoliosis (AIS) has been repeatedly documented. Several computer algorithms have been used to classify AIS based on the geometrical features, but none have attempted to analyze its treatment patterns.

PURPOSE

To use self-organizing maps (SOM), a kind of artificial neural networks, to reliably classify AIS cases from a large database. To analyze surgeon's treatment pattern in selecting curve regions to fuse in AIS using Lenke classification and SOM.

STUDY DESIGN

This is a technical concept article on the possibility and benefits of using neural networks to classify AIS and a retrospective analysis of AIS curve regions selected for fusion.

PATIENT SAMPLE

A total of 1,776 patients surgically treated for AIS were prospectively enrolled in a multicentric database. Cobb angles were measured on AIS patient spine radiographies, and patients were classified according to Lenke classification.

OUTCOME MEASURES

For each patient in the database, surgical approach and levels of fusion selected by the treating surgeon were recorded.

METHODS

A Kohonen SOM was generated using 1,776 surgically treated AIS cases. The quality of the SOM was tested using topological error. Percentages of prediction of fusion based on Lenke classification for each patient in the database and for each node in the SOM were calculated. Lenke curve types, treatment pattern, and kappa statistics for agreement between fusion realized and fusion recommended by Lenke classification were plotted on each node of the map.

RESULTS

The topographic error for the SOM generated was 0.02, which demonstrates high accuracy. The SOM differentiates clear clusters of curve type nodes on the map. The SOM also shows epicenters for main thoracic, double thoracic, and thoracolumbar/lumbar curve types and transition zones between clusters. When cases are taken individually, Lenke classification predicted curve regions fused by the surgeon in 46% of cases. When those cases are reorganized by the SOM into nodes, Lenke classification predicted the curve regions to fuse in 82% of the nodes. Agreement with Lenke classification principles was high in epicenters for curve types 1, 2, and 5, moderate in cluster for curve types 3, 4, and 6, and low in transition zones between curve types.

CONCLUSIONS

An AIS SOM with high accuracy was successfully generated. Lenke classification principles are followed in 46% of the cases but in 82% of the nodes on the SOM. The SOM highlights the tendency of surgeons to follow Lenke classification principles for similar curves on the SOM. Self-organizing map classification of AIS could be valuable to surgeons because it bypasses the limitations imposed by rigid classification such as cutoff values on Cobb angle to define curve types. It can extract similar cases from large databases to analyze and guide treatment.

Should Shoulder Balance Determine Proximal Fusion Levels in Patients With Lenke 5 Curves?

STUDY DESIGN

Multicenter review of prospectively collected data.

OBJECTIVES

To identify the frequency of an opposite high shoulder in Lenke 5 patients and evaluate factors that influence preoperative and postoperative shoulder balance.

SUMMARY OF BACKGROUND DATA

A high left shoulder is an indication to extend the fusion proximally in a right thoracic curve. Some apply a similar rule to high right shoulders in patients with left thoracolumbar/lumbar curves.

METHODS

A prospective multicenter adolescent idiopathic scoliosis database was queried for patients with Lenke 5 curves and minimum 2-year follow-up. Preoperative and postoperative shoulder height differences were recorded and categorized by the opposite shoulder (right shoulder in a left thoracolumbar curve) as high (greater than 1 cm), level (0-1 cm), and low (less than 1 cm). Preoperative and postoperative radiographic variables and Scoliosis Research Society questionnaire scores were evaluated.

RESULTS

Of the 104 patients identified, 37% had level shoulders and 53% had a high opposite shoulder. A high shoulder was associated with a greater mean thoracic Cobb (31°) than a level (24°) or low shoulder (26°) (p = .008). Postoperatively, 64% of patients had level shoulders (less than 1 cm); 93% had a shoulder difference less than 2 cm. Preoperative lumbar Cobb was a significant predictor of postoperative shoulder height (p = .051). A slightly greater proportion of preoperative high shoulders (36%) had a nonselective fusion than those with level (27%) or low (9%) shoulders. Among the 29 patients with a preoperative moderate or significant high shoulder (greater than 2 cm), 3 continued to have a high shoulder greater than 2 cm that was not influenced by fusing the thoracic spine. There were no significant differences in preoperative or postoperative Scoliosis Research Society scores based on shoulder height (p > .05).

CONCLUSIONS

Half of all Lenke 5 curves have a high opposite shoulder that is influenced by the size of the compensatory thoracic curve. Postoperatively, most patients had level shoulders. Inclusion of the thoracic spine did not influence postoperative shoulder balance.

Abnormal bone quality versus low bone mineral density in adolescent idiopathic scoliosis: a case-control study with in vivo high-resolution peripheral quantitative computed tomography

BACKGROUND CONTEXT

Adolescent idiopathic scoliosis (AIS) is associated with low bone mass that could persist into early adulthood and is an important prognostic factor for curve progression. Previous studies were confined to areal bone mineral density measurement that was a two-dimensional investigation for a three-dimensional structure. Evaluation of volumetric BMD (vBMD) and other bone quality parameters are important for gaining in-depth understanding of the etiopathogenesis of AIS.

PURPOSE

The objective of this study was to carry out direct in vivo measurement of bone quality in AIS using high-resolution peripheral quantitative computed tomography (HR-pQCT) and compare the correlation of bone quality with osteopenia between AIS and control subjects.

STUDY DESIGN/SETTING

A case-control study.

PATIENT SAMPLE

Newly diagnosed AIS girls (n=112) and non-AIS girls (n=115) between 11 and 13 years.

OUTCOME MEASURES

Areal bone mineral density of bilateral femoral necks and HR-pQCT of the nondominant distal radius were performed.

METHODS

Areal bone mineral density of femoral necks was measured by dual-energy X-ray absorptiometry. Subjects were classified into the osteopenic (Z score less than or equal to -1) and nonosteopenic (Z score more than -1) groups. Bone quality parameters, including bone morphometry, trabecular bone microarchitecture, and vBMD, were measured by HR-pQCT (XtremeCT; Scanco Medical, Zurich, Switzerland).

RESULTS

In AIS, the osteopenic group had lower measurements in cortical area, cortical thickness, average vBMD, compact bone vBMD, trabecular vBMD, trabecular bone volume to tissue volume ratio, and trabecular thickness compared with nonosteopenic AIS subjects. In contrast, among the non-AIS controls, the osteopenic group had lower measurements only in bone morphometry, average vBMD, and compact bone vBMD but not in trabecular vBMD and all other trabecular bone microarchitecture parameters.

CONCLUSIONS

This is the first study using HR-pQCT to compare the correlation of bone quality with osteopenia in AIS and non-AIS subjects. It provides new insights and highlights the unique bone quality profile with predominant changes in the trabecular compartment in association with osteopenia being notably only detected in the AIS subjects. Further studies in this area are warranted for defining the metabolic nature and biomechanical sequelae of derangement in bone mass and bone quality and their roles in the etiopathogenesis of AIS.

Review of current technologies and methods supplementing brace treatment in adolescent idiopathic scoliosis

PURPOSE

To report on the current technologies and methods supplementing brace treatment in adolescent idiopathic scoliosis.

METHODS

A comprehensive literature review was performed to determine the effectiveness of bracing, to report on imaging techniques that can assist in the assessment of bracing, to understand the roles of the biomechanical treatment concepts on bracing and to address the importance of the quality of life of the brace wearers.

RESULTS

The effectiveness of bracing still remains controversial. Many technologies are still in development to improve the bracing process and quantify the effects of bracing. Imaging techniques with decreased or no radiation are promising in providing more frequent data on curve progression for patients. Computer-assisted design models have been used for both fitting and manufacturing the brace to patient contours. Ultrasound has been developed as a new means of diagnosing scoliosis and determining the effects of a brace on a patient's spine in real time. The brace treatment outcomes are correlated to the quantity and the quality of brace usage. Compliance monitors and force sensors have been developed to track the quality of brace usage. Improvements to brace wear also require consideration of patient quality of life. Surveys have been developed to describe the effects of family influence and self-image on bracing effectiveness of patient quality of life.

CONCLUSIONS

Bracing remains a highly qualitative process, relying on the empirical judgment of the physicians and orthotists, along with buy-in with the patient. The suggested improvements will help to push bracing into a more evidence-based practice.

[Is local bone graft sufficient to maintain the surgical correction in adolescent idiopathic scoliosis curves?]

OBJECTIVE

The purpose of this study was to compare postoperative clinical and radiological results in adolescent idiopathic scoliosis curves treated by posterior arthrodesis using autogenous bone graft from iliac crest (CI) versus only local autograft bone (HL).

PATIENTS AND METHODS

A retrospective matched cohort study was conducted on 73 patients (CI n=37 and HL n=36) diagnosed with adolescent idiopathic scoliosis and treated surgically by posterior arthrodesis. The mean post-operative follow-up was 126 months in the CI group vs. 66 months in the HL group. The radiographic data collected consisted of preoperative, postoperative, and final follow-up antero-posterior and lateral full-length radiographs. Loss of correction and quality of arthrodesis were evaluated by comparing the scores obtained from the Spanish version of the SRS-22 questionnaire.

RESULTS

There were significant differences in the post-operative results as regards the correction of the Cobb angle of the main curve (HL 61 ± 15% vs. CI 51 ± 14%, P<.004), however a greater loss of correction was found in the local bone group (CI 4.5 ± 7.3° vs. HL 8.5 ± 6.3°, P=.02). There were no significant differences as regards the correction of the Cobb angle of the main curve at the end of follow-up. There were no clinical differences between the two groups in the SRS-22 scores.

CONCLUSION

At 5 years of follow-up, there was a statistically significant greater loss of radiographic correction at the end of final follow-up in the local bone graft group. However clinical differences were not observed as regards the SRS-22 scores.

Acute pulmonary embolism following adolescent idiopathic scoliosis correction surgery: case report and review of literature

Pulmonary embolism is a significant complication of surgery. This report presents a case of suspected fatal postoperative acute pulmonary embolism following posterior correction surgery in a 16-year-old female with idiopathic scoliosis. The patient presented with a suspected pulmonary embolism 2 h postoperatively. She lost consciousness quickly, and cardiac respiratory arrest occurred. Cardiopulmonary resuscitation was started immediately. The patient was stabilized but underwent a further suspected pulmonary embolism the following day. Cardiopulmonary resuscitation was performed again, but she lost consciousness and respirator support was required. At 40 days after surgery, a computed tomography scan revealed an area of necrotic brain tissue near the lateral cerebral ventricle. The patient remained in a comatose state for 16 months, after which active management was withdrawn. This case reminds us to be alert to potentially fatal postoperative pulmonary embolism in young patients without any risk factors for thrombosis.

Reinstrumentation for rapid curve progression after implant removal following posterior instrumented fusion in adolescent idiopathic scoliosis: a case report

BACKGROUND CONTEXT

Spinal implants are occasionally removed due to infection or soft tissue irritation secondary to prominence. Several studies have reported loss of scoliotic curve correction after implant removal. However, further review of the literature reveals no similar cases of rapid curve progression following implant removal in patients with adolescent idiopathic scoliosis (AIS) necessitating repeat posterior instrumented fusion.

PURPOSE

To describe a 15-year-old female AIS patient treated by posterior instrumented fusion, who developed unusual rapid coronal and sagittal curve progression after implant removal.

STUDY DESIGN

Case report.

METHODS

Retrospective case report.

RESULTS

A 15-year-old female with Lenke type 1A AIS underwent a successful posterior spinal fusion with instrumentation. She initially had no complications after surgery, but three years after instrumentation, her implants were removed due to pain secondary to implant prominence. Fifteen months after removal, the main thoracic curve increased, compared with radiographs taken before removal, from 29° to 57°. This development required the patient to undergo additional surgery, which involved multiple osteotomies and posterior reinstrumentation.

CONCLUSIONS

We must acknowledge that a remarkable amount of progression can occur rapidly following implant removal in scoliotic patients. Taking this into consideration,we need to carefully explain to patients that removal of their implants entails a risk of progressive deformity and that they need to follow-up with their physician after implant removal.

Discriminative Properties of the Spinal Appearance Questionnaire Compared With the Scoliosis Research Society-22 Revised

STUDY DESIGN

Longitudinal cohort.

OBJECTIVES

To determine the responsiveness of the Spinal Appearance Questionnaire (SAQ) in patients with adolescent idiopathic scoliosis (AIS) undergoing surgical correction of the deformity.

SUMMARY OF BACKGROUND DATA

The SAQ has been found to be a valid and reliable measure in patients with AIS. A recently published factor analysis and scoring system has been shown to be applicable to all Lenke types and had greater correlation to the curve magnitude than the Scoliosis Research Society (SRS) Appearance and Total score.

METHODS

From a prospective multicenter database, 126 AIS patients who underwent correction of the spinal deformity with complete SAQ and SRS-22 Revised data at baseline and 2-year follow-up were identified. Discriminative properties of the SAQ domains (Expectations, Appearance, and Total) and SRS domains (Appearance, Activity, Pain, Mental, Satisfaction, and Total) were compared by computing the effect size (ES) and the standardized response mean (SRM).

RESULTS

The SAQ Total had the largest ES (1.8) and SRM (1.5). This was followed by the SAQ Appearance, with an ES of 1.7 and SRM of 1.4; and the SAQ Expectations, with an ES of 1.5 and SRM of 1.2. Among the different SRS domains, only the Appearance (ES = 1.2, SRM = 1.1), Satisfaction (ES = 0.8, SRM = 0.6), and Total scores (ES = 0.8, SRM = 0.9) had effect sizes that were considered large. The SRS Mental domain had a moderate effect size (ES = 0.3, SRM = 0.3), whereas the Activity (ES = 0.0, SRM = 0.0) and Pain (ES = 0.2, SRM = 0.2) domains had small effect sizes.

CONCLUSIONS

The SAQ is sensitive and responsive to change, as evidenced by the large effect size for both domain and the Total score. The effect sizes are larger than those for any of the SRS domains, including Appearance and Total scores.

Multicenter Comparison of the Factors Important in Restoring Thoracic Kyphosis During Posterior Instrumentation for Adolescent Idiopathic Scoliosis

STUDY DESIGN

Multicenter review, prospectively collected data.

OBJECTIVES

To determine factors predictive of postoperative correction of hypokyphosis when segmental posterior pedicle screw implants were used in treating thoracic adolescent idiopathic scoliosis (AIS).

SUMMARY OF BACKGROUND DATA

Correcting hypokyphosis, which is common in patients with thoracic AIS, may be important in preventing junctional kyphosis, maintaining lumbar lordosis, and improving pulmonary function.

METHODS

A multicenter, prospective database was reviewed for Lenke type 1-4 AIS patients with preoperative kyphosis of 5° to 20°, treated with posterior pedicle screws and 5.5-mm rods. Surgeons with a minimum of 20 patients identified were included. Patients were divided into 2 groups postoperatively based on first erect X-rays: those remaining hypokyphotic (HK) (T5-T12 less than 20° or an increase less than 5° in T5-T12 kyphosis) and those restored to normal kyphosis (NK) (T5-T12 greater than 20° with 5° or more increase). Regression analysis was done on 5 preoperative factors thought to influence the postoperative kyphosis: preoperative kyphosis, surgeon, rod material (standard, high-strength, and ultra-high-strength steel; titanium; and cobalt chromium), implant density, and use or no use of a posterior release (Ponte osteotomies).

RESULTS

Of 280 patients included, 222 remained hypokyphotic and 53 achieved normal kyphosis. There were no differences in preoperative kyphosis (13.4° ± 5°, HK group vs. 14.5° ± 4°, NK group) and age (14.7, HK group vs. 14.6, NK group) between patients brought to greater than 20° (NK) and those who remained less than 20° (HK). Of the factors evaluated, the surgeon who performed the operation was the only significant predictor of restoration of normal kyphosis. Comparison of surgeons showed that the rate of normalizing kyphosis ranged from 6% to 42% (p = .001). There was no difference in the degree of preoperative kyphosis among surgeons.

CONCLUSIONS

Restoration of thoracic kyphosis remains a challenge in posteriorly treated thoracic AIS patients. The surgeon was the only significant predictor of restoring normal kyphosis, which emphasizes the importance of intraoperative techniques.

Surgical Site Infection in Adolescent Idiopathic Scoliosis Surgery

OBJECTIVE

To define the current rate of postoperative surgical site infections (SSIs) in a large prospective series of surgical adolescent idiopathic scoliosis (AIS) cases.

METHODS

A multicenter, prospective database of patients who underwent surgical correction of AIS was reviewed. Early SSIs were defined as occurring within 90 days after the index operation, as per the Center for Disease Control's definitions. Treatment and outcome information on all confirmed SSIs was compiled. Variables associated with the occurrence of an SSI were evaluated.

RESULTS

Of the 1,757 patients analyzed, 28 developed an SSI within the first 90 days postoperatively (1.6%). Patient weight was associated with SSI (p < .001). There was a trend in correlation with the number of levels fused (p = .07) and blood loss as a percentage of blood volume (p = .07) and the incidence of SSI. There was no correlation with any other variables. There was variation in the rate of SSI among the 9 centers, ranging from 0.6% to 4.4% (p = .27). Of the 28 infections, 26 resolved with surgery and/or antibiotics and did not need implant removal. Only 2 patients had late pain. In addition to the 28 confirmed SSIs, there were an additional 68 other wound issues (4.2%) that did not meet the Center for Disease Control criteria for an SSI.

CONCLUSIONS

Early SSIs after AIS surgery occurred at a rate of 1.6%. The federal mandate to eliminate SSI and the proposed lack of reimbursement for its treatment may change clinical practice, and these data provide average SSI rates across multiple centers for future comparison. Investigations into variations in practice between centers might yield areas for potential improvement in SSI for AIS patients. Fortunately, 92% of patients were able to retain their implants and were free of pain at final follow-up.

Spondylolisthesis in Operative Adolescent Idiopathic Scoliosis: Prevalence and Results of Surgical Intervention

STUDY DESIGN

Retrospective, matched cohort.

OBJECTIVES

To evaluate patients with spondylolisthesis who underwent spinal fusion for adolescent idiopathic scoliosis (AIS); compare their overall satisfaction using the Scoliosis Research Society's outcome measure (SRS-22) with that of patients without spondylolisthesis; examine postoperative radiographs to determine slip progression and scoliotic correction; and provide a guide in choosing the lowest instrumented vertebral level.

SUMMARY OF BACKGROUND DATA

Spondylolisthesis has been reported to occur in 6.2% of patients with AIS. To the authors' knowledge, there is no prior matched-pair study comparing radiographic and clinical outcomes of patients who have undergone spinal fusion for AIS in the setting of spondylolisthesis.

METHODS

Records and radiographs of 349 patients with AIS treated with spinal fusion were reviewed to evaluate for spondylolisthesis. A set of matched controls with AIS but without spondylolisthesis was assembled. Data collected included Lenke curve type, curve magnitude, level and grade of spondylolisthesis, preoperative and postoperative slip angle, number of levels between the fusion and the spondylolisthesis, SRS-22 scores, curve correction, and slip progression.

RESULTS

Sixteen patients with operatively treated AIS (4.58%) also had spondylolisthesis. No patients with low-grade slips had progression of the slip at final follow-up of an average of 4 years. All fusions and listheses were separated by at least 3 levels. No significant differences were seen in postoperative SRS-22 scores between patients with AIS and those with AIS and spondylolisthesis.

CONCLUSIONS

Adolescent idiopathic scoliosis and spondylolisthesis can be treated independently. Powerful curve corrections can be obtained and maintained for at least 4 years in patients with AIS regardless of the presence of spondylolisthesis. Preserving motion of 3 levels between a posterior spinal fusion for AIS and a spondylolisthesis does not contribute to slip progression. According to SRS-22 questionnaire data, patients with concomitant AIS and spondylolisthesis who undergo spinal fusion procedures do well clinically.

Head and trunk mass and center of mass position estimations in able-bodied and scoliotic girls

Anthropometric tables are not applicable to calculate the scoliotic trunk mass and center of mass (COM). The purposes of this study were: (1) to estimate the head and trunk mass and COM in able-bodied and scoliotic girls using a force plate method, (2) to estimate head and trunk COM offset compared to those of the body, and (3) the use of mean ratios to estimate the head and trunk COM calculated in this study and that calculated according to a conventional three-dimensional (3D) method compared to the measured values. Twenty-one scoliotic and twenty able-bodied girls participated. The subjects stood upright with arms beside the trunk on a force plate that collected data at 60 Hz for a period of 5s. The anteroposterior and mediolateral positions of the body COM were obtained from the mean center of pressure values. The height of the body COM was estimated by the reaction board method. Afterwards a body segment was displaced and changes in force plate readings were recorded and applied to estimate the head and trunk mass and COM. Trunk offset was defined as the difference between the COM of the body and head and trunk. The measured head and trunk COM was compared to values obtained by the mean ratios calculated from this study and given by the conventional 3D method. The relative head and trunk mass and the anteroposterior trunk offset were larger in scoliotic girls. The force plate method gave similar results to measured COM values for both groups underlying its capability to provide a more accurate estimation of COM related values. Thus, the use of mean ratios of 0.5538 and 0.6438 obtained in this study to estimate the head and trunk mass and COM position in scoliotic girls can overcome the main drawbacks of current anthropometric methods, if direct measurements cannot be taken.

The effect of tranexamic acid in blood loss and transfusion volume in adolescent idiopathic scoliosis surgery: a single-surgeon experience

PURPOSE

Intraoperative blood loss in scoliosis surgery often requires transfusions. Autogenous blood decreases but does not eliminate risks typically associated with allogenic blood transfusion. Costs associated with transfusions are significant. Tranexamic acid (TXA) has been shown to decrease blood loss in cardiac and joint surgery. Few studies have examined its use in pediatric spine surgery, and the results are inconsistent. The aim of this study was to determine whether TXA decreases intraoperative blood loss and transfusion requirements in adolescent idiopathic scoliosis patients undergoing posterior spinal fusion by a single surgeon.

METHODS

The medical records and operative reports of surgically treated patients with adolescent idiopathic scoliosis between 2000 and 2009 were retrospectively reviewed. The inclusion criteria were: (1) patients who underwent instrumented posterior spinal fusion, (2) had complete medical records, and (3) were treated by the same surgeon. Forty-nine patients who met the inclusion criteria were divided into two groups: Group A (25 patients) received TXA, while Group B (24 patients) did not receive TXA.

RESULTS

After controlling for age at the time of surgery, gender, and number of vertebral levels fused, the mean intraoperative blood loss was significantly lower in Group A (537 ml) than in Group B (1,245 ml) (p = 0.027). The mean volume of blood transfused intraoperatively was 426 and 740 ml for Group A and Group B, respectively. The difference was not statistically significant after controlling for age, gender, and number of levels fused (p = 0.078).

CONCLUSION

TXA significantly decreased intraoperative blood loss in posterior spinal fusions performed for adolescent idiopathic scoliosis.

Experience with transforaminal interbody fusion in corrective surgery for adolescent idiopathic scoliosis

One of the surgical goals during the treatment of adolescent idiopathic scoliosis (AIS) is to preserve segments and thus mobility while achieving a well-balanced spine on all planes. The transforaminal interbody fusion (TLIF) technique allows for a significant degree of rotational correction and thus may allow for preservation of more mobile segments. This retrospective study analyzed the use of TLIF in AIS patients who underwent surgery between 2006 and 2009 at a single center, and discusses the degree of curve correction, complications and outcomes. All curves were classified using the Lenke classification system. Standing posterior-anterior Cobb angle, sagittal and coronal balance, percent correction, and end/stable/neutral/apical vertebra were determined on preoperative, postoperative and follow-up radiographs. Nine patients were identified (eight women and one man) ranging in age from 11.6-18 years. All TLIF procedures were performed at the L2/3 level. Lenke curves included 5CN (n=5), 5BN (n=2), and 6CN (n=2). Average follow-up was 27.4 months (range, 12-57 months). Average postoperative curve correction was 79%. One patient underwent revision surgery. All patients remained stable from a clinical and radiographic standpoint on their last follow-up visit. TLIF is an important adjunct in the surgical management of select AIS patients. By allowing for greater rotational correction, it may be possible to preserve one more mobile segment without decompensation or overcorrection. To our knowledge, this is the first report on the role of TLIF in AIS. Future studies are warranted in determining those who will maximally benefit from this technique.

Generalized epileptic seizure in an adolescent idiopathic scoliosis (AIS) patient with syringomyelia after deformity correction surgery

INTRODUCTION

Adolescent idiopathic scoliosis and epilepsy are pathologies rarely seen together. In this study we report an AIS case we operated in which epilepsy was seen post operatively. We want to emphasize the items one should pay attention in such cases.

PRESENTATION OF CASE

In a 14-year-old girl with AIS and concomitant syringomyelia and spondylolisthesis, posterior deformity correction and fusion were performed. After stabilization the patient was discharged on the 10th day of discharge epileptic seizure appeared.

DISCUSSION

In scoliosis surgery, the mechanic stress and bleeding caused by the operation itself can cause neurological problems due to primary nervous system injury. The operation and bleeding during and after the operation, pulmonary and cardiac functional instability, metabolic imbalance can be the causes of epileptic seizures.

CONCLUSION

Epilepsy seen after a major surgery like scoliosis surgery, can be either as a result of central nervous system origined vascular and hypoxic problems or metabolic. In our case we concluded that massive hemorrhage must have induced epilepsy. In neurologic consultations the case was considered as an incidental epileptic picture.

Effect of the intraoperative wake-up test in sevoflurane-sufentanil combined anesthesia during adolescent idiopathic scoliosis surgery: a randomized study

STUDY OBJECTIVE

To investigate the effect of the intraoperative wake-up test on sevoflurane-sufentanil anesthesia for adolescent idiopathic scoliosis (AIS) surgery.

DESIGN

Randomized, double-blind, parallel trial.

SETTING

Operating room.

PATIENTS

30 ASA physical status 1 patients, aged 13 to 20 years, scheduled for AIS surgery.

INTERVENTIONS

Patients were randomized to two groups: Group W patients received sevoflurane-sufentanil combined anesthesia and underwent the intraoperative wake-up test; Group NW received sevoflurane-sufentanil combined anesthesia without the wake-up test. Anesthesia was induced with an intravenous (IV) injection of midazolam, propofol, and sufentanil and maintained with sevoflurane inhalation, a target-controlled infusion (TCI) of sufentanil, and IV infusion of cisatracurium besylate.

MEASUREMENTS

The primary outcome was postoperative delirium. Secondary outcomes were duration of surgery, duration of anesthesia, intraoperative blood loss and transfusion, exposure of drugs administered, time to eye opening, extubation, and consciousness.

MAIN RESULTS

Postoperative delirium occurred in one patient from each group (P > 0.05). There were no significant differences between the two groups in duration of surgery (322 ± 65 min vs 336 ± 72 min), duration of anesthesia (356 ± 76 min vs 368 ± 81 min), intraoperative blood loss (1847 ± 423 mL vs 1901 ± 451 mL) and transfusion (1663 ± 398 mL vs 1649 ± 382 mL), average exposure of drugs (72 ± 13 mg vs 75 ± 15 mg for propofol, 116 ± 28 μg vs 109 ± 25 μg for sufentanil, and 22 ± 5 vs 23 ± 4 mg for cisatracurium), time to eye opening (4.7 ± 1.5 min vs 4.8 ± 1.4 min), extubation (7.5 ± 2.0 min vs 7.3 ± 2.2 min), and consciousness (8.9 ± 1.8 min vs 9.1 ± 2.1 min) (all P > 0.05).

CONCLUSIONS

Sevoflurane-sufentanil combined anesthesia provides hemodynamic stability and rapid recovery from AIS surgery. There is no correlation between the intraoperative wake-up test and postoperative delirium after sevoflurane-sufentanil combined anesthesia.

Is Routine Postoperative Radiologic Follow-up Justified in Adolescent Idiopathic Scoliosis?

STUDY DESIGN

Retrospective review.

OBJECTIVES

To determine whether routine periodic radiographic examination is worthwhile in adolescent idiopathic scoliosis (AIS) patients undergoing instrumented fusion with third-generation implants.

SUMMARY OF BACKGROUND DATA

In common practice, patients who have undergone surgery for idiopathic scoliosis are followed up for a minimum of 2 years by clinical assessment and routine radiographic study at 3, 6, 12, and 24 months. The radiation related to these examinations is not negligible. To our knowledge, the use of routine radiographic follow-up after posterior spinal fusion for adolescent idiopathic scoliosis has not been evaluated.

METHODS

We retrospectively analyzed full-spine X-rays and clinical records from the first 2 postoperative years of 43 patients. We sought any clinical feature (eg, pain, deformity progression, material protrusion) justifying X-ray, and any relevant radiologic finding (eg, loss of correction, instrumentation loosening, junctional kyphosis).

RESULTS

Excluding the immediate postoperative films, 14.8% of X-rays were clinically justified, 8.3% were associated with a relevant finding, and 4.3% led to a therapy change. All patients with clinical deformity progression had a relevant X-ray finding. Pain was associated with a relevant finding in 23.5% of cases (positive predictive value, 0.1); 7.4% of films with no clinical justification showed a relevant finding (negative predictive value, 0.86). Lower Risser sign increased the risk of having a relevant radiographic finding (p < .05).

CONCLUSIONS

With the current use of third-generation implants, routine biplanar postoperative X-rays at 3, 6, 12, and 24 months do not seem to be justified in AIS and should be avoided in mature, asymptomatic patients.

Anterior Dual Rod Versus Posterior Pedicle Fixation Surgery for the Surgical Treatment in Lenke 5C Adolescent Idiopathic Scoliosis: A Multicenter, Matched Case Analysis of 42 Patients

STUDY DESIGN

Multicenter matched case analysis.

OBJECTIVE

Compare patients with Lenke 5C scoliosis surgically treated with anterior spinal fusion with dual rod instrumentation and anterior column support versus posterior release and pedicle screw instrumentation.

SUMMARY OF BACKGROUND DATA

Treatment of single, structural, lumbar and thoracolumbar curves in patients with adolescent idiopathic scoliosis (AIS) has been the subject of some debate. Previous papers directly comparing these approaches are problematic because of heterogeneity of the groups, nonrandomized protocols, and surgeon bias and variation of instrumentation (upper instrumented vertebrae and lower instrumented vertebrae) in relation to the defined Cobb angle (upper end vertebra and lower end vertebrae). This report sought to remedy these flaws by analyzing a database of Lenke 5C AIS and performing matched cases.

METHODS

We analyzed 96 patients with Lenke 5C AIS curves based on radiographic and clinical data at 3 institutions, surgically treated between 2001 and 2005 with minimum 2-year follow-up. Case matched criteria (age within 1 year, sex, curve within 5°, lower end vertebrae, and lower instrumented vertebrae) yielded 21 matched patient pairs. We evaluated and compared multiple clinical and radiographic parameters.

RESULTS

We observed no significant statistical differences between groups in any preoperative clinical or radiographic parameters. At final follow-up, the major curve measured 8° (83%) in the posterior spinal fusion group, compared with 13° (72%) in the anterior spinal fusion group (p = .002). Estimated blood loss was similar in both groups. Hospital stay was significantly shorter in the posterior spinal fusion group. There were no differences in radiographic complications, such as proximal junctional kyphosis.

CONCLUSIONS

At a minimum of 2 years' follow-up in a multicenter, matched case analysis, adolescents with Lenke 5C curves demonstrated statistically significantly better curve correction and shorter hospital stays when treated with a posterior release with pedicle screw instrumented fusion compared with an anterior instrumented fusion with dual rods for similar patient populations.

Converting Scoliosis Research Society-24 to Scoliosis Research Society-22r in a Surgical-Range, Medical/Interventional Adolescent Idiopathic Scoliosis Patient Cohort

STUDY DESIGN

Prospective questionnaire administration study.

OBJECTIVES

To assess the ability to translate total and domain scores from Scoliosis Research Society (SRS)-24 to SRS-22r in a surgical-range, medical/interventional adolescent idiopathic scoliosis (AIS) patient population.

SUMMARY OF BACKGROUND DATA

Conversion of SRS-24 to SRS-22r is demonstrated in an operative cohort of patients with AIS, but not in a medical/interventional patient population.

METHODS

We simultaneously administered SRS-24 and SRS-22r questionnaires to 75 surgical-range, medical/interventional AIS patients and compared them. We performed analysis by regression modeling to produce conversion equations from SRS-24 to SRS-22r.

RESULTS

The total SRS-24 score for these medical/interventional AIS patients was 92.5 ± 9.45 (mean, 3.9 ± 0.39), and the total SRS-22r score was 93.5 ± 9.63 (mean, 4.3 ± 0.44). The correlation between these 2 groups was fair (R² = 0.77) and improved to good when mental health or recall questions were removed. The correlation was also fair for total pain domains (R² = 0.73). However, there was poor correlation for general self-image (R² = 0.6) and unacceptable for post-treatment self-image (R² = 0.01), general function (R² = 0.52), activity function (R² = 0.56), and satisfaction (R² = 0.53). Compared with a published population of operative AIS patients, R² values for total SRS-24 scores, pain, general self-image, activity function, and satisfaction were similar (p > .05). The R² values for general function and combined general and activity function were significantly different between the operative and medical/interventional cohorts.

CONCLUSIONS

Scoliosis Research Society-24 can be converted to SRS-22r scores with fair accuracy in the surgical-range, medical/interventional AIS patient population for total score, and total pain domains. The SRS-24 translates unacceptably to the SRS-22r in self-image, function, and satisfaction domains. The SRS-24 to SRS-22r conversion equations are similar to operative AIS patients, except for the function domain. Caution should be used when interpreting results based on translation of SRS-24 to SRS-22r values.

Outcomes Following Posterior Fusion for Adolescent Idiopathic Scoliosis With and Without Autogenous Iliac Crest Bone Graft Harvesting

STUDY DESIGN

Retrospective.

SUMMARY OF BACKGROUND DATA

There is continued controversy regarding the morbidity associated with harvesting iliac crest bone graft (ICBG). More important, its effect on clinical outcomes is poorly understood.

OBJECTIVES

The purpose of this study was to determine whether harvesting ICBG affects clinical outcomes after posterior instrumented fusion in patients with adolescent idiopathic scoliosis (AIS).

METHODS

We identified patients enrolled in a prospective, multicenter database of patients with AIS who had posterior instrumented fusion with complete preoperative and 2-year postoperative Scoliosis Research Society (SRS)-22R data. Patients who had a previous fusion, thoracoplasty, or anterior surgery were excluded. We classified patients into 2 groups: those who underwent ICBG harvest (ICBG group) and those who did not (non-ICBG group).

RESULTS

We included 342 patients in the ICBG group versus 563 in the non-ICBG group. There were no significant differences in preoperative age (14.9 vs. 14.8; p = .178), major Cobb angle (51.3 vs. 51.8; p = .782), minor Cobb angle (34.8 vs. 35.1; p = .846), or Pain (4.11 vs. 4.11; p = .912), Appearance (3.29 vs. 3.33; p = .384), Activity (4.15 vs. 4.14; p = .847); Mental (3.95 vs. 4.00; p = .313), or Total (3.86 vs. 3.87; p = .603) SRS-22R scores. The average operative time was slightly longer in the ICBG group (293.55 vs. 276.21 minutes; p = .002). Estimated blood loss was greater in the ICBG group (939.47 vs. 723.63 mL; p = .000; 12.2% vs. 9.2% estimated blood volume; p = .000). The average number of levels fused was similar between groups (10.6 vs. 10.3; p = .137). There were no significant differences in any of the postoperative SRS-22R domains: Pain (4.30 vs. 4.34; p = .373), Appearance (4.23 vs. 4.19; p = .310), Activity (4.31 vs. 4.33; p = .509), Mental (4.20 vs. 4.23; p = .532), Satisfaction (4.42 vs. 4.43; p = .870), or Total Score (4.27 vs. 4.29; p = .674). By 2-year follow-up, there was 1 nonunion reported in the ICBG group and none in the non-ICBG group.

CONCLUSIONS

After posterior instrumented fusion surgery for AIS, ICBG harvesting was associated with longer operative times and increased blood loss, but did not influence 2-year outcomes, which included pain and appearance scores.

Are Thoracic Curves With a Low Apex (T11 or T11/T12) Really Thoracic Curves?

STUDY DESIGN

Multicenter; review of prospectively collected data.

OBJECTIVES

To determine whether curves with an apex at T11 or T11/T12 represent a combination of thoracic and thoracolumbar curves or constitute their own class of curves.

SUMMARY OF BACKGROUND DATA

Curves with an apex at T11 and T11/T12 are classified by the Scoliosis Research Society and Lenke classification as thoracic curves.

METHODS

We reviewed 1,835 adolescent idiopathic scoliosis cases from a multicenter database. Based on the most common curve apex levels (thoracic [TH] curves, T9; thoracolumbar/lumbar [TL/L] curves, L1), we created 2 comparison groups that represented classic examples of TH and TL/L curves. We identified 66 cases with an apex at T11-T11/T12 and compared them with 320 cases with a T9 apex, and 126 cases with an L1 apex. We compared characteristics of these 3 groups (p < .05) and completed a radiographic review of the T11-T11/T12 group.

RESULTS

The curve direction of the 3 groups was significantly different (TL/L, 84% left; TH, 3% left; and T11-T11/T12, 16% left) (p < .001). The mean number of vertebrae in curves for the T11-T11/T12 group (7.1 ± 1.2) fell between the value for the TL/L (5.7 ± 0.8) and TH (7.3 ± 1.0) groups. The T11-T11/T12 curves had a greater trunk shift than TL/L (p = .002) and TH (p = .011) curves. There was no difference among the 3 groups in terms of major curve Cobb magnitude (p = .09) or age at surgery (p = .76). Radiographic review of the T11-T11/T12 curves revealed 3 curve patterns: 21 long single curves (32%), 28 short single curves (42%), and 17 double thoracic curves (26%).

CONCLUSIONS

We suggest caution in lumping curves with an apex at T11 or T11-12 disc together with other thoracic apices in studies involving primary thoracic curves, because some of these curves have features much more typical of thoracolumbar curves.

Anterior surgery for adolescent idiopathic scoliosis

Anterior open scoliosis surgery using the dual rod system is a safe and rather effective procedure for the correction of scoliosis (50-60 %). Thoracic hypokyphosis and rib hump correction with open anterior rather than posterior instrumentation appear to be the better approaches, although the latter is somewhat controversial with current posterior vertebral column derotation devices. In patients with Risser grade 0, hyperkyphosis and adding-on may occur with anterior thoracic spine instrumentation. Anterior thoracoscopic instrumentation provides a similar correction (65 %) with good cosmetic outcomes, but it is associated with a rather high risk of instrumentation (pull-out, pseudoarthrosis) and pulmonary complications. Approximately 80 % of patients with adolescent idiopathic scoliosis (AIS) curves of >70° have restrictive lung disease or smaller than normal lung volumes. AIS patients undergoing anterior thoracotomy or anteroposterior surgery will demonstrate a significant decrease in percentage of predicted lung volumes during follow-up. The thoracoabdominal approach and thoracoscopic approach without thoracoplasty do not produce similar changes in detrimental lung volume. In patients with severe AIS (>90°), posterior-only surgery with TPS provides similar radiographic correction of the deformity (44 %) with better pulmonary function outcomes than anteroposterior surgery. Vascular spinal cord malfunction after segmental vessel ligation during anterior scoliosis surgery has been reported. Based on the current literature, the main indication for open anterior scoliosis instrumentation is Lenke 5C thoracolumbar or lumbar AIS curve with anterior instrumentation typically between T11 and L3.

Pathogenesis and biomechanics of adolescent idiopathic scoliosis (AIS)

Adolescent idiopathic scoliosis is defined as a scoliosis that starts after the age of ten and has no clear underlying disease as a reason for its development. There is, however, a disparity between the growth of the vertebral bodies anteriorly and that of the posterior elements. The vertebral bodies grow faster than the posterior elements, resulting primarily in a lordosis. The diminished dorsal growth impedes the ventrally located vertebral bodies from increasing in height, forcing them to become distorted, i.e., rotate, in order to create space for themselves. This produces a rotational lordosis. The idea of looking at it in this way dates back to Somerville in 1952. Many recent studies have confirmed this idea and have shown that the spinal canal is shorter than the anterior ligament of the vertebral bodies. In a mathematical model of the spine it was demonstrated that-although the vertebral column in humans is still predominantly loaded in an axial direction-certain segments of the human spine (especially the backward inclined segments) are subject to dorsally directed shear loads as well. In addition to the antero-posterior difference in growth, there is also a deformation of the vertebral bodies itself in 3-D. This is probably secondary and not primary effects, but this question is still under discussion. For the treatment of scoliosis, the biomechanical principles of axial and transverse forces are used. The combination of axial and transverse loads is most beneficial for all curves. The axial forces provide most of the corrective bending moment when deformity is severe, while the transverse loads take over the correcting function when deformity is mild. The deformity angle of 53° is the break-even point for the axial and transverse loads. In more severe curves transverse forces become less and less efficient, while axial forces rapidly gain more and more effect.

Clinical investigation and imaging

Adolescent idiopathic scoliosis (AIS) affects 2-4 % of children and is diagnosed between age 10 and skeletal maturity. The female to male ratio for mild curves less than 20° is 1.5:1; however, progression to a severe deformity occurs more often in females (Weinstein in JAMA 289(5):559-567, 2003). Despite significant ongoing research, including into the genetic basis for AIS, there are currently no identifiable causes, and therefore the disorder still remains a diagnosis of exclusion. History, physical examination and radiographic assessment must exclude other possible causes of spinal deformity and are crucial in predicting the risk of curve progression. History should focus on family history, menarche, presence or absence of pain, sports activities and neurologic changes. Physical examination concentrates on anthropometric data, pubertal staging, neurologic testing and specific investigation of the spine, with the Adams' forward bending test being the most meaningful step to evaluate trunk rotation. Definitive diagnosis cannot be made without imaging. The gold standard remains plain radiography with assessment of the Cobb angle on a standing coronal radiograph of the entire spine. A lateral X-ray is used for assessing sagittal balance and for evaluating the deformity in the sagittal plane. If available, surface topography can accompany the follow-up in AIS, reducing the radiation exposure. The role of magnetic resonance imaging (MRI) in AIS is an ongoing matter of debate. Common indications for MRI are the presence of an atypical curve pattern and abnormal neurological findings.

Classification of adolescent idiopathic scoliosis (AIS)

In 1983 Howard King presented his classification system for adolescent idiopathic scoliosis (AIS) based on the experience with Harrington rod instrumentation. Curves were divided into five types and guidelines and recommendations for which levels should be instrumented were given to preserve motion as much as possible. As segmental instrumentation systems began to gain favor over the Harrington rods this system failed and led to the development of a new classification system which was presented by Lawrence Lenke in 2001. In order to define a curve type by the Lenke classification, one must identify the curve type, the lumbar modifier and, for the first time in any classification system for scoliosis, the sagittal profile was also included. The Lenke classification showed higher inter and intra-reliability compared to the King classification. It also provided a better and more reliable tool to assist surgeons in choosing the best method of treatment for each curve pattern. Although the Lenke classification is more comprehensive and reliable than the King classification it is still far from perfect. It does not address the rotational component of the deformity. New technologies which provide three-dimensional (3D) reconstruction of the spine may serve as a basis for a truly 3D classification of scoliosis and for new therapeutic concepts.

Idiopathic scoliosis: etiological concepts and hypotheses

Scoliosis is diagnosed as idiopathic in 70 % of structural deformities affecting the spine in children and adolescents, probably reflecting our current misunderstanding of this disease. By definition, a structural scoliosis should be the result of some primary disorder. The goal of this article is to give a comprehensive overview of the currently proposed etiological concepts in idiopathic scoliosis regarding genetics, molecular biology, biomechanics, and neurology, with particular emphasis on adolescent idiopathic scoliosis (AIS). Despite the fact that numerous potential etiologies for idiopathic scoliosis have been formulated, the primary etiology of AIS remains unknown. Beyond etiology, identification of prognostic factors of AIS progression would probably be more relevant in our daily practice, with the hope of reducing repetitive exposure to radiation, unnecessary brace treatments, psychological implications, and costs-of-care related to follow-up in low-risk patients.

Epidemiology of adolescent idiopathic scoliosis

Adolescent idiopathic scoliosis is a common disease with an overall prevalence of 0.47-5.2 % in the current literature. The female to male ratio ranges from 1.5:1 to 3:1 and increases substantially with increasing age. In particular, the prevalence of curves with higher Cobb angles is substantially higher in girls than in boys: The female to male ratio rises from 1.4:1 in curves from 10° to 20° up to 7.2:1 in curves >40°. Curve pattern and prevalence of scoliosis is not only influenced by gender, but also by genetic factors and age of onset. These data obtained from school screening programs have to be interpreted with caution, since methods and cohorts of the different studies are not comparable as age groups of the cohorts and diagnostic criteria differ substantially. We do need data from studies with clear standards of diagnostic criteria and study protocols that are comparable to each other.

Natural history of adolescent idiopathic scoliosis: a tool for guidance in decision of surgery of curves above 50°

The purpose of this lecture was to give an overview of the natural history of adolescent idiopathic scoliosis (AIS), in order to serve as guidance in the decision of performing surgery or not for the specific patient with AIS. A literature review was performed. Studies concerning long-term outcome in patients with adolescent idiopathic scoliosis that had received no treatment were used. Outcome in terms of curve size, pulmonary function, back function and quality or life/social life was compared. The literature review showed that single thoracic curves of 50°-75° progress 0.73°/year over a 40-year period. AIS do not result in increased mortality, but pulmonary symptoms may be associated with larger curves. Back pain is more frequent among patients with AIS. No study using modern quality of life questionnaires exists, but for social function, childbearing, and marriage no apparent disadvantageous effects were reported compared to the healthy population. The conclusion is that most individuals with AIS and moderate curve size around maturity function well and lead an acceptable life in terms of work and family. Some patients with larger curves have pulmonary problems, but not to the extent that this affects the life span. This needs to be taken into account when discussing surgery with the individual patient.

Bracing in adolescent idiopathic scoliosis

The article reviews the present knowledge about brace treatment for adolescent idiopathic scoliosis (AIS). Indications, technique, problems, and results, are presented based on the literature. It is stressed by the authors that more scientific evidence is needed to reach a final conclusion whether brace treatment in AIS is effective or not.

The psychopathological influence of adolescent idiopathic scoliosis in korean male : an analysis of multiphasic personal inventory test results

OBJECTIVE

There are few published studies which have documented psychopathological abnormalities in patients with of adolescent idiopathic scoliosis (AIS) The aim of this study was to evaluate the psychopathological influence of AIS in Korean 19-year-old males.

METHODS

The authors compared the Korean military multiphasic personal inventory (KMPI) military profiles of 105 AIS cases (more than 10 degrees of Cobb's angle without surgical treatment) with the KMPI profiles of 108 normal controls. The AIS group was split depending on Cobb's angle to further evaluate this relation by the severity of AIS.

RESULTS

A significantly decreased result on the faking-good response scale and an significantly increased result on the faking-bad response were observed in the AIS group compared to the control (p<0.012). The neurosis scale results, including anxiety, depression and somatization symptoms, were significantly increased in the AIS group compared to the control (p<0.010). The severity level of personality disorder and schizophrenia were also significantly increased in the AIS group (p<0.010). Differences in KMPI scale scores were not related to the severity of AIS.

CONCLUSION

Young males with AIS tend to have abnormal results on the multiphasic personal inventory test compared to normal volunteers, suggesting that AIS may be related to psychopathology in the young male group in Korea. Although these psychopathology in AIS were differently observed compared to normal controls, but not interfered with military life. Clinicians are recommended to pay attention the psychopathological traits of patients with AIS.