Bi-planar spinal stereoradiography of adolescent idiopathic scoliosis: considerations in 3D alignment and functional balance

Comparisons of Interapical Distance and Coronal Balance Measurements Among Standing Positions in Participants With and Without Adolescent Idiopathic Scoliosis Using 3D Ultrasound Imaging

STUDY DESIGN

Cross-sectional study.

OBJECTIVE

The objective of this study was to quantify whether interapical distance and coronal balance measured on 3D ultrasound (3DUS) images differed among 10 standing positions of participants with and without adolescent idiopathic scoliosis (AIS).

SUMMARY OF BACKGROUND DATA

Apical vertebral translation (AVT) is an indicator of clinical symptoms and treatment outcomes in AIS. Stereoradiography simultaneously captures a frontal and lateral image, yet patients are required to elevate their arms during the examination and varied positioning may impact coronal plane measurements. Ultrasound can assess these measurements without exposing participants to radiation.

MATERIALS AND METHODS

Females with and without AIS were recruited from a scoliosis clinic, and e-mail advertisements, respectively. Participants underwent 3DUS scans in 10 positions: standing; arms anteriorly supported in 60° of shoulder flexion; fingers to clavicles, chin, zygomatic processes, and eyebrows; shoulders abducted at 90° with hands open and thumbs on shoulders; hands on anterior wall with and without blocks; and hands unsupported. AVT and coronal balance measurements were obtained using custom software. Positions and groups were compared using repeated measures ANOVAs with Sidak pairwise comparisons.

RESULTS

Fifty-nine females had a mean age, height, and weight of 17.5±4.9 years, 162.8±5.8 cm, and 56.2±10.6 kg, respectively. Seventeen single and 14 double curve participants were included with mean maximum curve angles of 26.4°±3.6° and 25.2°±3.1°, respectively. Overall, there were no statistically significant differences in interapical distance or coronal balance among the 10 positions, as well as in coronal balance between the groups ( P >0.05). The interapical distance of participants without AIS significantly differed from those with single curves in eight positions and from those with double curves in all 10 positions.

CONCLUSIONS

The positions evaluated may be interchangeable for coronal plane lateral deviation measurements of females with AIS.

What imaging does my AIS patient need? A multi-group survey of provider preferences

INTRODUCTION

Adolescent idiopathic scoliosis (AIS) is a common diagnosis managed by pediatric orthopedic surgeons with nonoperative radiographic monitoring representing a cornerstone of treatment. Differences in practices and techniques for obtaining radiographic studies contribute to variation, cost of care, and hamper data aggregation. We surveyed several large organizations dedicated to children's orthopedics or scoliosis care to obtain a consensus for radiographic evaluation of AIS.

METHODS

A REDCap-based survey was developed across four institutions and beta-tested by staff and fellows from a single institution. The finalized survey was distributed to members of POSNA, PSSG, and SOSORT, and shared on social media. Participants were asked to rank the importance of various datapoints in radiographic assessment of the spinal deformity, skeletal maturity, and study indications during initial, subsequent, preoperative, and final office visits for AIS. Response rate for the overall group was 26%.

RESULTS

Cobb angle was considered the most important (> 94%) radiographic index across all time points. For positioning, 46% of respondents favored arms bent touching clavicles as the ideal positioning for X-rays, and another 24% favored arms down with palms forward (Table 2). The majority of respondents obtain lateral X-rays at the first visit (99%) and at the preoperative visit (70%). At the preoperative visit, sagittal contour (86%), apex location (85%), and Lenke classification (73%) were considered important factors to record. Flexibility studies are primarily obtained at the preoperative visit (89%) and 81% of respondents prefer bending films as the flexibility technique of choice. Regarding measures of skeletal maturity, Sanders bone age was considered to be the most important by over 70% of respondents across initial, subsequent, preoperative and brace wean visits (Fig. 2). MRIs were obtained routinely by 34% of respondents and only when the patient had a concerning symptom or finding for 67% of respondents.

CONCLUSIONS

Despite large variations in radiographic examination of AIS, large areas of agreement were found. It is important to establish standards for positioning patients, evaluating skeletal maturity, and obtaining assessments including lateral views, flexibility studies, and advanced imaging. Establishing common practices for radiographic evaluation of AIS will allow for less variation in care and for critical questions to be answered through registry formation and large multicenter data collection.

SIGNIFICANCE

This study establishes current practitioner opinion on the radiographic evaluation of the AIS patient. Minimum data sets are useful for data aggregation and answering research questions in the face of data variability.

LEVEL OF EVIDENCE

Level V.

Investigation of spinopelvic sagittal alignment and its correlations in asymptomatic pediatric populations

The sagittal alignment of the cervical spine and its relationship with spinopelvic parameters plays a crucial role in maintaining overall postural balance. This study aims to provide normative values for these parameters in asymptomatic pediatric subjects, aiding in the enhancement of treatment and evaluation strategies for spinal deformities and disorders. Conducted at the Third Hospital of Hebei Medical University, this retrospective study included 307 asymptomatic pediatric volunteers aged 4-18 years, screened for scoliosis from January 2021 to July 2023. Participants underwent whole-length EOS examinations following a standard protocol. Radiographic measurements of cervical and spinopelvic parameters were taken, and statistical analyses were performed using SPSS software to assess variations by age and gender. Normative values for cervical sagittal and spinopelvic parameters were established, demonstrating significant differences based on age and sex. Key findings include a strong correlation between the C2-7 Cobb angle and T1 and C7 slopes, with an observed increase in cSVA particularly pronounced in boys. Age and gender significantly influenced the normative values of these parameters, suggesting the importance of considering these factors in pediatric spinal assessments. This study establishes crucial normative values for cervical and spinopelvic parameters in a large pediatric cohort, highlighting the influence of age and sex on spinal sagittal alignment. The findings underscore the necessity of tailoring spinal assessment approaches in pediatric populations to improve the clinical evaluation and management of spinal health, providing a foundational benchmark for future research in pediatric spinal deformities and disorders.

Improvement of Cardiac and Pulmonary Function in Patients With Moderate-to-Severe Idiopathic Scoliosis After Posterior Corrective surgery-A Single-Center, Prospective Cohort Study

STUDY DESIGN

Prospective single-center cohort study.

OBJECTIVE

To evaluate cardiac morphology, cardiac function, and pulmonary hypertension impairment in patients with idiopathic scoliosis (IS) and their changes one year after scoliosis surgery.

METHODS

70 patients with IS with predominantly thoracic curvature Cobb angle >40° were enrolled and categorized into moderate (<70°) and severe (≥70°) groups. Preoperative radiography and transthoracic echocardiography were performed. Postoperatively, 51 patients completed a one-year follow-up and were compared with preoperative data.

RESULTS

(1) Left ventricular end-diastolic diameter (LVEDD), left ventricular global longitudinal strain (LVGLS), and e were lower and E/e was higher in the moderate vs severe group, and the aortic internal diameter and LVEF were lower in the severe group than in the control group (P < 0.05); (2) Right ventricular free wall strain (RVFWS), tricuspid annular plane systolic excursion (TAPSE), and TAPSE/systolic pulmonary artery pressure (SPAP) were lower, and SPAP was higher in the moderate vs severe group than in the control group (P < 0.05); (3) The thoracic curve Cobb angle was significantly negatively correlated with LVEDD, SV, LVGLS, RVFWS, TAPSE, TAPSE/SPAP and FVC and FEV1 measured/predicted (P < 0.05), and positively correlated with SPAP (P < 0.05); (4) After one-year postoperative follow-up, LVEDD, LVGLS, SV, e, RVFWS, TAPSE and TAPSE/SPAP were higher, and E/e and SPAP were lower (P < 0.05) compared to pre-operation.

CONCLUSION

Cardiac morphology, left and right heart function, and pulmonary function were impaired in patients with IS, and which showed significant improvement after posterior corrective surgery.

The effect of arm positions used during radiography on spinal alignment parameters assessed by 3D ultrasound imaging in adolescents with and volunteers without idiopathic scoliosis

PURPOSE

Clinicians monitor scoliosis progression using multiple radiographs during growth. During imaging, arms must be elevated to visualize vertebrae, possibly affecting sagittal alignment. This study aimed to determine the arm position that best represents habitual standing (and possibly allowing hand-based skeletal maturity assessment) to obtain frontal and lateral stereo-radiographs as measured using frontal, sagittal, and transverse angles.

METHODS

Females with and without, and males with Adolescent Idiopathic Scoliosis (AIS) were recruited consecutively. Patients were scanned using 3D Ultrasound imaging (3DUS), in 10 arm positions; habitual standing, arms supported anteriorly at 60° flexion, fingers to clavicle, chin, zygomatic, and eyebrows, arms abducted 90°, hands on wall, on blocks, and unsupported. Axial vertebral rotation (AVR) differences, frontal, and sagittal curve angles were measured. Repeated measures ANOVAs with Sidak post-hoc tests compared positions.

RESULTS

Ninety females with and without AIS with mean age, and height of 17 ± 4 years, and 162 ± 6 cm, and ten males with AIS of 16 ± 3 years, and 174 ± 11 cm, respectively, were included. Female AIS single-curve showed larger curves in standing in all positions excluding hands on blocks (p > 0.05). Sagittal parameters showed decreases in kyphosis in arms abducted 90° and increases in lordosis in fingers to cheeks/eyebrows (p > 0.05). AVR twist was not significantly affected by position. Male AIS showed comparable results to females, but no significant differences were detected.

CONCLUSION

No position represented habitual standing for all groups. When arms are raised, decreases in curve angle were shown in single-curve patients, kyphosis decreased, and lordosis increased in all groups. Most accurate positioning for all parameters was in fingers to clavicle/chin position.

Systematic review of imaging comparisons of spinal alignment among standing positions in healthy adolescents or adolescents with idiopathic scoliosis: SOSORT 2023 award winner

PURPOSE

Clinicians detect scoliosis worsening over time using frequent radiographs during growth. Arms must be elevated when capturing sagittal radiographs to visualize the vertebrae, and this may affect the sagittal angles. The aim was to systematically review the published evidence of the effect of arm positions used during radiography on spinal alignment parameters in healthy participants and those with AIS.

METHODS

Design was registered in PROSPERO (CRD42022347494). A search strategy was run in Medline, Embase, CINAHL, and Web of Science. Healthy participants ≥ 10 years old and participants with AIS between 10 and 18 years old, with Cobb angles > 10° were included. Study quality was assessed using the Appraisal tool for Cross-Sectional Studies (AXIS). Meta-analysis was performed where possible.

RESULTS

Overall, 1332 abstracts and 33 full texts were screened. Data was extracted from 7 included studies. The most common positions were habitual standing, fists on clavicle, and active (arms raised unsupported). Kyphosis, lordosis, and sagittal vertical axis (SVA) were most measured. Meta-analysis showed significantly decreased kyphosis (SMD = 0.78, 95%CI 0.48, 1.09) and increased lordosis (SMD = - 1.21, 95%CI - 1.58, - 0.85) when clavicle was compared to standing. Significant posterior shifts in SVA were shown in clavicle compared to standing (MD = 30.59 mm, 95%CI 23.91, 37.27) and active compared to clavicle (MD = - 2.01 mm, 95%CI - 3.38, - 0.64). Cobb angles and rotation were rarely studied (1 study).

CONCLUSION

Meta-analysis evidence showed elevated arm positions modify sagittal measurements compared to standing. Most studies did not report on all relevant parameters. It is unclear which position best represent habitual standing.

Maximal Axial Vertebral Rotation in Adolescent Idiopathic Scoliosis: Is the Apical Vertebra the Most Rotated?

STUDY DESIGN

Retrospective cross-sectional study.

OBJECTIVES

It is generally believed that the apical vertebra has the largest axial rotation in adolescent idiopathic scoliosis. We investigated the relationship between apical axial vertebral rotation (apicalAVR) and maximal axial vertebral rotation (maxAVR) in both major and minor curves using biplanar stereo-imaging.

METHODS

EOS 2D/3D biplanar radiograph images were collected from 332 patients with adolescent idiopathic scoliosis (Cobb angle range 10°-122°, mean age 14.7 years). Based on the X-ray images, with the help of 3D full spine reconstructions Cobb angle, curvature level, apicalAVR and maxAVR were determined. These parameters were also determined for minor curves in Lenke 2, 3, 4, 6 type patients. Maximal thoracic rotation and maximal thoracolumbar/lumbar rotation were calculated. Statistical analysis was performed with descriptive statistics, Shapiro-Wilk test, and Wilcoxon signed-rank test.

RESULTS

The apical vertebrae were the most rotated vertebra in only 40.4% of the major curves, and 31.7% in minor curves. MaxAVR significantly exceeded apicalAVR values in the major curves (P < .001) as well as in minor curves (P < .001). The 2 parameters differed significantly in each severity group and Lenke type.

CONCLUSIONS

The apical vertebrae were not the most rotated vertebra in more than half of cases investigated indicating that apicalAVR and maxAVR should be considered as 2 distinct parameters, of which maxAVR fully describes the axial dimension of scoliosis. Furthermore, the substitution of maxAVR for the apicalAVR should be especially avoided in double and triple curves, as the apical vertebra was even less commonly the most rotated in minor curves.

Quantitative imaging of the spine in adolescent idiopathic scoliosis: shifting the paradigm from diagnostic to comprehensive prognostic evaluation

PURPOSE

We aimed to provide a perspective review of the available quantitative imaging modalities of the spine for prognostic evaluation of the adolescent idiopathic scoliosis (AIS).

METHODS

A technical description of the current imaging technologies for quantitative assessment of the pediatric spine with scoliosis was provided, and the pros and cons of each method were discussed. Imaging modalities that quantify the overall 3D alignment of the spine as well as the structural specification of the spinal bone, intervertebral disc, endplates, and ligaments as it pertains to development and progression of the idiopathic spinal deformities in adolescents were discussed.

RESULTS

Low-dose and microdose stereoradiography, ultrasound, and rasterstereography provide quantitative imaging of the 3D spinal alignment with low or no radiation in standing posture which allows repetitive imaging for early detection of the curve development. Quantitative magnetic resonance imaging, including ultrashort dual-echo time and T1-rho can provide quantitative assessment of the spinal tissues relevant to development of idiopathic spinal deformity in pediatric population. New computed tomography scans that uses dual-energy can provides high-resolution measure of the current-state of the bone quality and morphology as well as the osteogenic properties of the bone by quantitative evaluation of the bone marrow.

CONCLUSION

The presented imaging modalities can provide a wide spectrum of quantifiable information relevant to development and progression of the spinal deformity. Clinical application of these technologies can change the paradigm in clinical assessment of the pediatric scoliosis by improving our understanding of the pathogenesis of the idiopathic scoliosis.

Sagittal curvature of the spine as a predictor of the pediatric spinal deformity development

BACKGROUND

The sagittal curvature of the spine is hypothesized to play an important role in induction of spinal deformities in adolescent idiopathic scoliosis. We previously showed an S shaped flexible rod, with the same curvature as the pediatric sagittal spinal curve, produces scoliotic-like deformities under physiologic loading. Yet, detailed characteristics of the pediatric sagittal spinal curves associated with higher risk of scoliosis are not well defined.

METHODS

A total of 32 patients in a population with a high prevalence of idiopathic-like scoliosis, 22q11.2 deletion syndrome (22q), were included and followed up for at least two-years. We developed a reduced order finite element model (FEM) of the sagittal profile of these 32 patients where the spine was modeled as an S shaped elastic rod. We related the geometrical parameters of the sagittal curves and the deformed FEM of the corresponding S shaped rods to the risk of scoliosis development at two-year follow-up in this cohort.

RESULTS

Variations in the sagittal curvature in the cohort of 22q patients resulted in five different deformity patterns shown by finite element analyses. Two sagittal plane deformity pattern groups had high rate of scoliosis development (86% and 100%) whereas the other 3 groups had less than 50% rate of scoliosis development (40%, 33%, and 0%). The pre-scoliotic position of the inflection point (where lordosis turns into kyphosis), the ratio of the spinal curvatures above and below the inflection point, and the length of the spinal curve above and below the inflection point were significantly different between the five deformity patterns groups, p < 0.05.

CONCLUSION

Combination of geometrical parameters of the sagittal profile prior to onset of scoliosis can relate to the development of spinal deformity in pediatric population.

Displacement of Centre of Pressure during Rehabilitation Exercise in Adolescent Idiopathic Scoliosis Patients

Background. Adolescent idiopathic scoliosis (AIS) is included into the category of pathologies that could affect postural control. Rarely AIS shows symptoms but often compromises the normal positioning of the head, trunk and, more generally, of the limbs in the space. We used a stabilometric platform to evaluate the motor control outcomes during a self-elongation in girls with AIS. Methods. In 10 girls with AIS, we evaluated the center of pressure (COP) modifications on a baropodometric platform in a standing position and after a self-elongation correction. Results. All the outcomes (except the eccentricity) showed an increasement during the self-elongation exercise even if the significant differences were not found. Conclusion. SE correction contributes to ameliorate the COP symmetry with a better repercussion on the balance management. This highlights the importance of repetitions during all activities of daily life.

Three-dimensional classification of the Lenke 1 adolescent idiopathic scoliosis using coronal and lateral spinal radiographs

BACKGROUND

Classification of the spinal deformity in adolescent idiopathic scoliosis (AIS) remains two-dimensional (2D) as the spinal radiographs remain the mainstay in clinical evaluation of the disease. 3D classification systems are proposed, however are time consuming. We here aim to evaluate the clinical application of a 3D classification system by the use of only posterior-anterior and lateral radiographs in Lenke 1 adolescent idiopathic scoliosis (AIS).

METHODS

Forty Lenke 1 AIS were classified by five observers following a three-step flowchart, developed based on our previous 3D classification system. This 3D classification characterizes the curve in the frontal and sagittal views and infers the third dimension with rules based on prior data to determine the 3D subtypes of the curve. Repeated rating was performed for 20 randomly selected patients in the same cohort. In addition to the classification by the raters, the 3D model of the spines were generated to determine the actual curve subtype based on the algorithm that was originally used to develop the 3D classification system. The interobserver and intraobserver reliability and the classification accuracy were determined for both 3D and axial classifications of the cohort.

RESULTS

The interobserver reliability was moderate to strong with a kappa value between 0.61-0.89 for 3D and axial classifications. Comparing the mathematical classification and the raters' classification, the classification accuracy among all raters ranged between 56 and 89%.

CONCLUSION

We evaluated the reliability of a previously developed 3D classification system for Lenke 1 AIS patients when only two-view spinal radiographs are available. Radiologists and orthopedic surgeons were able to identify the 3D subtypes of Lenke 1 AIS from the patients' radiographs with moderate to strong reliability. The new 3D classification has the potential to identify the subtypes of the Lenke 1 AIS without a need for quantitative 3D image post-processing.

Restoration of Thoracic Kyphosis in Adolescent Idiopathic Scoliosis Over a Twenty-year Period: Are We Getting Better?

STUDY DESIGN

A multicenter, prospectively collected database of 20 years of operatively treated adolescent idiopathic scoliosis (AIS) was utilized to retrospectively examine pre- and postoperative thoracic kyphosis at 2-year follow-up.

OBJECTIVE

To determine if the adoption of advanced three-dimensional correction techniques has led to improved thoracic kyphosis correction in AIS.

SUMMARY OF BACKGROUND DATA

Over the past 20 years, there has been an evolution of operative treatment for AIS, with more emphasis on sagittal and axial planes. Thoracic hypokyphosis was well treated with an anterior approach, but this was not addressed sufficiently in early posterior approaches. We hypothesized that patients with preoperative thoracic hypokyphosis prior to 2000 would have superior thoracic kyphosis restoration, but the learning curve with pedicle screws would reflect initially inferior restoration and eventual improvement.

METHODS

From 1995 to 2015, 1063 patients with preoperative thoracic hypokyphosis (<10°) were identified. A validated formula for assessing three-dimensional sagittal alignment using two-dimensional kyphosis and thoracic Cobb angle was applied. Patients were divided into 1995-2000 (Period 1, primarily anterior), 2001-2009 (Period 2, early thoracic pedicle screws), and 2010-2015 (Period 3, modern posterior) cohorts. Two-way repeated measures analysis of variance and post-hoc Bonferroni corrections were utilized with P < 0.05 considered significant.

RESULTS

Significant differences were demonstrated. Period 1 had excellent restoration of thoracic kyphosis, which worsened in Period 2 and improved to near Period 1 levels during Period 3. Period 3 had superior thoracic kyphosis restoration compared with Period 2.

CONCLUSION

Although the shift from anterior to posterior approaches in AIS was initially associated with worse thoracic kyphosis restoration, this improved with time. The proportion of patients restored to >20° kyphosis with a contemporary posterior approach has steadily improved to that of the era when anterior approaches were more common.

LEVEL OF EVIDENCE

3.

Adolescent idiopathic scoliosis: evaluating perioperative back pain through a simultaneous morphological and biomechanical approach

Background

Adolescent idiopathic scoliosis (AIS) has been associated with diminished postural stability and a greater prevalence of back pain. Currently, the literature is lacking information on the effect of spinal fusion on both postural stability and its association with back pain. Our objectives were to evaluate the postsurgical effect of spinal morphological changes on static standing balance and assess the influence of these alterations on reported pain throughout the perioperative period.

Methods

Twenty consecutive AIS patients schedule to undergo spinal fusion surgery were recruited and followed prospectively at the Shriners Hospitals for Children-Canada. Data was collected at the preoperative, 6 weeks and 6 months postoperative visits. Spinal morphology data was collected through 3D reconstructed simultaneous standing biplanar radiographs using the SterEOS software. Postural balance was assessed through Moticon© sensor insoles and analyzed through their software. The data was simultaneously collected as part of the Global Biomechanical and morphological Assessment. Pain was evaluated through self-reported questionnaires.

Results

Morphological curve parameters were significantly reduced after surgery. Balance parameters did not change significantly throughout the perioperative period with the exception of the Center of Pressure of the left foot medial/lateral transient shift (P = 0.017) at 6 weeks. Of note, preoperative balance parameters were associated with the degree of right thoracic Cobb angles (P = 0.029 R = 0.528). Pain scores significantly improved 6 weeks and 6 months after the surgery. Pain intensity diminished in the thoracic and lumbar spine but worsen in the neck region at the 6 weeks and 6 months postoperative time points (P = 0.044). Greater residual Cobb angle difference between Mid thoracic and Thoracolumbar/Lumbar curves was associated with greater pain severity at 6 weeks postop (P < 0.005). In addition, greater residual thoracic deformity was associated with significant pain severity 6 months after surgery (P < 0.05).

Conclusions

Improved spinal morphology of postsurgical AIS patients has no significant impact on their static standing balance. Suggesting that other factors apart from the spinal morphology may contribute to AIS patients’ balance during stance. Although balance did not influence pain severity, spinal morphology and its correction appear to have influenced the intensity and location of back pain.

Changes in the Position of the Junctional Vertebrae After Posterior Spinal Fusion in Adolescent Idiopathic Scoliosis: Implication in Risk Assessment of Proximal Junctional Kyphosis Development

BACKGROUND

The development of proximal junctional kyphosis (PJK) after posterior spinal fusion in adolescent idiopathic scoliosis is a major problem. Changes in the global sagittal parameters as they relate to PJK have been reported after surgery, however, the relationships between the changes in the upper-instrumented vertebra (UIV) during and after surgery as they relate to development of PJK have not been quantified. We hypothesize that the compensatory changes in the unfused segments of the spine over time are correlated with the surgically induced changes in the UIV position.

METHODS

Sixty adolescent idiopathic scoliosis patients (with at least 1-year follow-up) who underwent posterior spinal surgery were included retrospectively. Global spinal parameters were calculated using 3-dimensional models of the spine, additional parameters [proximal junctional kyphosis angle (PJKA), cervical lordosis angle] were measured manually before surgery and at 3 postoperative follow-ups. The 3-dimensional position of the vertebral body centroids was calculated for T1, UIV, and lower-instrumented vertebra at all timepoints. The sagittal position of T1, UIV, and lower-instrumented vertebra were correlated to the cervical lordosis, PJKA, lumbar lordosis, and pelvic tilt.

RESULTS

The position of T1 and UIV were significantly more anterior at first erect for patients who developed PJK. The posterior shift of UIV at the most recent follow-up as compared with the preoperative position was significant in both the PJK and non-PJK cohort. A larger anterior shift in UIV at first erect correlated with a larger T1 and UIV posterior shift at the most recent follow-up. At the most recent follow-up, a more posterior position of the UIV correlated with a larger angle of PJKA (P<0.05).

CONCLUSION

Both a larger anterior shift of UIV between preoperative and first erect and a more posterior position of UIV at the most recent follow-up was correlated with a higher PJKA. A larger anterior shift in the position of the UIV after surgery was associated with a higher posterior shift of UIV at the last follow-up. The surgically induced changes in the UIV are an important parameter associated with the development of PJK.

LEVEL OF EVIDENCE

Level IV.

A Novel Method to Measure the Sagittal Curvature in Spinal Deformities: The Reliability and Feasibility of 3-D Ultrasound Imaging

The objective of this study was to test the reliability of sagittal spinal curvature measurements using 3-D ultrasound in patients with adolescent idiopathic scoliosis (AIS). Ultrasound spinous process angle (USSPA) and ultrasound laminae angle (USLA) were measured on sagittal ultrasound images, while the Cobb angle (XCA) was measured on sagittal X-ray images. Intra-class correlation coefficients (ICC) for the intra- and inter-observer variability, linear regression analysis and Bland-Altman method, including mean absolute difference (MAD), were investigated to evaluate the reliability and validity of the two ultrasound angles compared with XCA. Excellent measurement reliabilities were demonstrated for both ultrasound angles (ICC ≥ 0.91). Moderate to good and significant linear correlations and good agreement were demonstrated between the ultrasound methods and XCA (Thoracic [R² ≥ 0.574] / Lumbar [R² ≥ 0.635]). No significant differences were found for the MADs between both corrected ultrasound angles and XCA. Sagittal ultrasound angles were demonstrated to be reliable for assessing sagittal curvature using spinous processes and laminae and to have good and significant correlations with XCAs. Since it is non-ionizing and relatively low cost, this method opens the possibility of providing frequent curve monitoring and evaluation, and screening for AIS patients, particularly based on sagittal profiles.

A hierarchical classification of adolescent idiopathic scoliosis: Identifying the distinguishing features in 3D spinal deformities

This study aimed to identify the differentiating parameters of the spinal curves’ 2D projections through a hierarchical classification of the 3D spinal curve in adolescent idiopathic scoliosis (AIS). A total number of 103 right thoracic left lumbar pre-operative AIS patients were included retrospectively and consecutively. A total number of 20 non-scoliotic adolescents were included as the control group. All patients had biplanar X-rays and 3D reconstructions of the spine. The 3D spinal curve was calculated by interpolating the center of vertebrae and was isotropically normalized. A hierarchical classification of the normalized spinal curves was developed to group the patients based on the similarity of their 3D spinal curve. The spinal curves’ 2D projections and clinical spinal measurements in the three anatomical planes were then statistically compared between these groups and between the scoliotic subtypes and the non-scoliotic controls. A total of 5 patient groups of right thoracic left lumbar AIS patients were identified. The characteristics of the posterior-anterior and sagittal views of the spines were: Type 1: Normal sagittal profile and S shape axial view. T1 is leveled or tilted to the right in the posterior view. Type 2: Hypokyphotic and a V shape axial view. T1 is tilted to the left in the posterior view. Type 3: Hypokyphotic (only T5-T10) and frontal imbalance, S shape axial view. T1 is leveled or tilted to the right, and 3 frontal curves. Type 4: Flat sagittal profile (T1-L2), slight frontal imbalance with a V shape axial view, T1 tilted to the left. Type 5: flat sagittal profile and forward trunk shift with a proximal kyphosis and S shape axial view. T1 is leveled or tilted to the right. In conclusion, a hierarchical classification of the 3D scoliotic spine allowed identifying various distinguishing features of the spinal curves in patients with a right thoracic curve in an orderly fashion. The subtypes’ characteristics resulting from this 3D classification can be identified from the pairs of the frontal and sagittal spinal curves i.e. X-rays in right thoracic AIS patients.

Preoperative Sagittal Spinal Profile of Adolescent Idiopathic Scoliosis Lenke Types and Non-Scoliotic Adolescents: A Systematic Review and Meta-Analysis

STUDY DESIGN

Systematic review and meta-analysis.

OBJECTIVE

This study aims to determine the differences in sagittal spinopelvic parameters between adolescent idiopathic scoliosis (AIS) Lenke types and non-scoliotic controls through a systematic review and meta-analysis of the available literature.

SUMMARY OF BACKGROUND DATA

AIS classification mainly focuses on frontal curve differences; however, the variations in the sagittal spinopelvic alignment in the current classification system is not fully established.

METHODS

Following preferred reporting items for systematic reviews and meta-analyses guidelines, searches were performed for sagittal spinal and pelvic parameters of Lenke types and non-scoliotic controls in PubMed, Scopus, EMBASE, and Cochrane databases. Selection criteria were: (1) age range 10 to 21 years; (2) Lenke types 1-6 (for AIS group) or non-scoliotic adolescents (for the control group); (3) preoperative data for T5-T12 thoracic kyphosis (TK), L1-S1 lumbar lordosis (LL), pelvic incidence (PI), sacral slope (SS), and sagittal vertical axis (SVA). (4) Written in English language. PI-LL mismatch was calculated from the weighted average of PI and LL. Publication bias between studies and within studies quality were assessed. A meta-regression compared each measured variable between groups. Thoracic (Lenke1 and 2) and thoracolumbar/lumbar (Lenke 5 and 6) scoliosis were combined and statistically compared with the control group.

RESULTS

Meta-analysis, including 81 AIS and 18 control studies, showed no significant differences in sagittal parameters between Lenke types and controls for LL, PI, PI-LL mismatch, SS, and SVA (P > 0.05). Publication bias was significant in Lenke 1 TK, Control LL, and Lenke 1, and 5 SVA. Stratification based on deformity region (thoracic vs. thoracolumbar/lumbar) showed no significant differences in sagittal spinopelvic parameters (P > 0.05).

CONCLUSION

No definitive difference was found between non-scoliotic adolescents and Lenke types in sagittal spinal and pelvic parameters. Future studies on developing a sagittal classification specific to AIS patients with a goal to improve surgical planning and outcome prediction are highly encouraged.

LEVEL OF EVIDENCE

4.

Sagittal Spinopelvic Alignment After Posterior Spinal Fusion in Adolescent Idiopathic Scoliosis: A Systematic Review and Meta-analysis

STUDY DESIGN

A systematic review and meta-analysis.

OBJECTIVE

The aim of this study was to determine the differences in the sagittal spinopelvic parameters between the nonscoliotic controls, preoperative, and different time points postoperative in Lenke 1 and 5 adolescent idiopathic scoliosis (AIS).

SUMMARY OF BACKGROUND DATA

The postoperative changes in the sagittal profile of Lenke 1 and 5 AIS at varying time points after posterior spinal fusion (PSF) has not been rigorously demonstrated; studies performed have had conflicting results.

METHODS

Sagittal spinal and pelvic parameters, T5-T12 thoracic kyphosis (TK), L1-S1 lumbar lordosis (LL), pelvic incidence (PI), sacral slope (SS), and sagittal vertical axis (SVA), for Lenke 1 and 5 preoperatively, at immediate, less than 2-year, and more than 2-year postoperatively, and for nonscoliotic adolescents were searched. Differences in the sagittal spinopelvic parameters between preoperative and the follow-ups and between the nonscoliotic and pre- and postoperative AIS subtypes were calculated through meta-analysis.

RESULTS

A total of 22 studies on Lenke1 (1229 patients), 13 studies on Lenke5 (437 patients), and 18 studies on controls (1636 patients) were reviewed. Among all the measured variables, only PI in Lenke1 was significantly different between the final follow-up and controls, P < 0.05. In Lenke 1, SVA was significantly more anterior at the immediate postoperative than preoperative, but continued moving posteriorly up to 2-year postoperative resulting in no significant difference in the SVA position between the final follow-up and preoperative, P > 0.05. In Lenke 5, SVA was significantly more posterior at the immediate postoperative and more anterior at the final follow-up than the preoperative measurements, p < 0.05.

CONCLUSIONS

Continuous changes in the sagittal spinal parameters should be expected after PSF. Normalization of the sagittal spinal parameters appears to be the rule after PSF, and watchful waiting appears to be appropriate in this population when viewing the lateral X-ray postoperatively.

LEVEL OF EVIDENCE

4.

Reliability of Rod Lengthening, Thoracic, and Spino-Pelvic Measurements on Biplanar Stereoradiography in Patients Treated With Magnetically Controlled Growing Rods

STUDY DESIGN

Cross-sectional study.

OBJECTIVE

To assess the inter- and intraobserver reliability of thoracic, spino-pelvic, and rod lengthening measurements made on biplanar spinal stereoradiography (EOS imaging) in children treated with magnetically controlled growing rod (MCGR).

SUMMARY OF BACKGROUND DATA

MCGR treatment aims to gain spine length while gradually correcting the spinal deformity. Monitoring thoracic and spino-pelvic parameters is crucial for successful management. EOS imaging is widely used for diagnosis and monitoring of children with Early Onset Scoliosis. However, there is a paucity of literature on the reliability of thoracic and spino-pelvic parameters on EOS imaging in children treated with MCGR.

METHODS

Three independent reviewers independently read a random assortment of 20 whole spine posteroanterior and lateral radiographs from patients treated with MCGR. The measurements were repeated 4 weeks after the initial read. The following radiological parameters were measured: Cobb angle of the main and compensatory curves, coronal balance, coronal T1-S1 and T1-T12 length, chest width and depth at T6, pelvic inlet width, MCGR distracted lengths, global kyphosis, proximal and distal junctional angle, lordosis, sagittal balance, pelvic incidence, pelvic tilt and sacral slope. Statistical analysis was performed with paired t test and Cronbach alpha for inter- and intraobserver reliability.

RESULTS

All measurements had good or excellent intra- and interobserver reliability (α>0.8; P < 0.05), except measurements of the proximal junctional angle which showed only poor intra- and interobserver reliability for patients with an upper instrumented vertebra cranial to T4.

CONCLUSION

EOS imaging is reliable for diagnosis and monitoring of children with Early Onset Scoliosis treated with MCGR. EOS imaging is particularly excellent for assessment of MCGR lengthening. Diagnosis and interpretation of early proximal junctional kyphosis within the cervicothoracic junction should be made with caution.

LEVEL OF EVIDENCE

3.

Are we simplifying balance evaluation in adolescent idiopathic scoliosis?

BACKGROUND

Clinical evaluation of the postural balance in adolescent idiopathic scoliosis has been measured by sagittal vertical axis and frontal balance. The impact of the scoliotic deformity in three planes on balance has not been fully investigated.

METHODS

47 right thoracic and left lumbar curves adolescent idiopathic scoliosis and 10 non-scoliotic controls were registered prospectively. 13 spinopelvic postural parameters were calculated from the 3-dimantional reconstructions of X-rays. 7 balance variables describing the position and sway of the center of pressure were recorded using a pressure mat. A regression analysis was used to predict sagittal vertical axis and frontal balance from the 7 balance variables. A canonical correlation analysis was performed between all the postural parameters and balance variables and the significant associations between the postural and balance variables were determined.

FINDINGS

sagittal vertical axis and frontal balance were not significantly associated with the position or sway of the center of pressure (p>0.05). Canonical correlation analysis showed significant associations between the postural variables in the 3 planes and center of pressure position (R²=0.81) and sway (R²=0.62), p<0.05.

INTERPRETATION

Frontal Cobbs, apical rotations, distal kyphosis, pelvic incidence, sacral slope, sagittal vertical axis, and frontal balance contributed to the postural balance in the cohort. The compensatory role of the pelvis and distal kyphosis in sagittal plane was underlined. Multidimensional analyses between the postural and balance variables showed the alignment of the thoracic, lumbar, and pelvis in the 3 planes, in addition to the global head-pelvic position impact on adolescent idiopathic scoliosis balance.

Timing of Changes in Three-Dimensional Spinal Parameters After Selective Thoracic Fusion in Lenke 1 Adolescent Idiopathic Scoliosis: Two-Year Follow-up

STUDY DESIGN

Retrospective analysis of the prospectively collected data.

OBJECTIVE

To investigate the relationship between the axial rotation of the unfused lumbar spine and the parameters of the instrumented thoracic spine at varying time points after selective thoracic fusion (STF) in Lenke 1B and 1C adolescent idiopathic scoliosis (AIS).

SUMMARY OF BACKGROUND DATA

The impact of STF on the spontaneous lumbar curve correction in AIS has been studied mainly in the frontal planes. The relationship between the spontaneous transverse plane correction of the lumbar spine and the parameters of the fused thoracic spine is not well documented.

METHODS

Twenty-one Lenke 1B and 1C patients who had received STF with minimum two years' follow-up were selected. Thoracic and lumbar Cobb angles, kyphosis, lordosis, and thoracic and lumbar apical vertebrae rotations were measured at preoperative, first-erect, six-month, one-year, and two-year follow-ups. The association between the lumbar apical vertebral rotation and other thoracic and lumbar variables at different time points were determined using regression analysis. The variables significantly predicting the lumbar axial rotation correction at two years were determined from the preceding follow-up visits.

RESULTS

Kyphosis, thoracic Cobb, thoracic apical vertebral rotation, and lumbar Cobb were significantly different between the preoperative and all the postoperative follow-ups (p < .05). At the two-year follow-up, a decrease in thoracic rotation and lumbar Cobb and a higher residual thoracic Cobb were associated with an improved spontaneous lumbar rotation (R² = 0.41, p < .05). Lumbar rotation at two years was predicted from thoracic derotation and lumbar Cobb at first erect (R² = 0.30, p < .05).

CONCLUSION

Spontaneous lumbar curve rotation correction correlated to the fused and unfused spinal parameters in the three anatomic planes. The relationship between thoracic and lumbar rotation persist up to two years after STF. Thoracic derotation is an important factor determining the lumbar rotation correction at two years after STF.

Influence of the proprioceptive neuromuscular facilitation exercise programs on idiopathic scoliosis patient in the early 20s in terms of curves and balancing abilities: single case study

The purpose of this study was to determine the influence of the proprioceptive neuromuscular facilitation (PNF) exercise programs for idiopathic scoliosis with a female patient in the early 20s in terms of her spinal curve and balancing abilities. The study subject was selected among 21-year-old female college students. There were no particular activities that the subject could not perform, but patient complained of difficulty in maintaining the standing position for a prolonged time. Patient chest X-ray results showed S-shaped curves tilted towards the left or right in the lumbar spine, thoracic spine, and cervical spine areas. The PNF exercise programs consists of seven therapeutic exercise programs, including home exercises considering the patients' balancing abilities, the lateral symmetry of the spinal sway, the distortion, and the height of the pelvis and scapula bones. The programs last for 6 weeks and includes three sessions per week, with each session lasting for 30 min. Before and after the execution of the PNF exercise programs, the subject was monitored for the changes in her spinal sways through chest X-ray tests. Also, using a balance measurement instrument, the subject's static and dynamic balancing abilities were tested. After executing the PNF exercise programs for 6 weeks, the spinal sways of the subject were corrected, and her static and dynamic balancing abilities were improved compared to the baseline values.

Three-dimensional reconstruction using stereoradiography for evaluating adult spinal deformity: a reproducibility study

PURPOSE

In addition to the sagittal alignment, impact of transverse plane parameters (TPP) and rotatory subluxation on patients reported outcomes were highlighted. One of the hypotheses for genesis of degenerative scoliosis is disc degeneration with increased axial vertebral (AVR) and intervertebral rotation (AIR). Therefore, TPP analysis at early stage of the scoliosis seems of particular interest. This study aims at assessing reliability of tridimensional (3D) reconstructions of adult spinal deformity (ASD) patients.

METHODS

Thirty ASD patients underwent biplanar radiographs and were divided into two groups (Cobb angle >30° or <30°). Spinal parameters and TPP (apical AVR, AIR of upper and lower level of main curve) were measured. Four operators performed 3D reconstructions twice. Intra and inter-observer reliabilities were analyzed using ISO standard 5725-2, to quantify the global standard deviation of reproducibility (S _R).

RESULTS

Mean Cobb angle was 31°, mean age 55 years (70% of female). Mean values of apical AVR, upper and lower level AIR were, respectively, 16° ± 15°, 6° ± 6° and 5° ± 5°. Spinopelvic parameters S _R were below 4.5°. For Cobb angle <30°, S _R was 7.8°, 9.6°, 4.5° and 4.9°, respectively, for AVR apex, torsion index, upper and lower AIR. Reliability was worse in the group of patients with Cobb angle above 30°.

CONCLUSIONS

3D analysis was reliable for Cobb and sagittal parameters. 3D analysis for TPP was reproducible when Cobb is below 30°. However, uncertainty is larger for Cobb above 30°. Nevertheless, 3D reconstructions could help surgeons to anticipate onset of rotatory subluxation while assessing axial rotation evolution for small deformity and choose best delay for surgical treatment.