Assessment of malalignment at early stage in adolescent idiopathic scoliosis: a longitudinal cohort study.

INTRODUCTION: Our objective was to assess abnormalities of the odontoid-hip axis (OD-HA) angle in a mild scoliotic population to determine whether screening for malalignment would help predict the distinction between progressive and stable adolescent idiopathic scoliosis (AIS) at early stage. MATERIALS AND METHODS: All patients (non-scoliotic and AIS) underwent a biplanar X-ray between 2013 and 2020. In AIS, inclusion criteria were Cobb angle between 10° and 25°; Risser sign lower than 3; age higher than 10 years; and no previous treatment. A 3D spine reconstruction was performed, and the OD-HA was computed automatically. A reference corridor for OD-HA values in non-scoliotic subjects was calculated as the range [5th-95th percentiles]. A severity index, helping to distinguish stable and progressive AIS, was calculated and weighted according to the OD-HA value. RESULTS: Eighty-three non-scoliotic and 205 AIS were included. The mean coronal and sagittal OD-HA angles in the non-scoliotic group were 0.2° and -2.5°, whereas in AIS values were 0.3° and -0.8°, respectively. For coronal and sagittal OD-HA, 27.5% and 26.8% of AIS were outside the reference corridor compared with 10.8% in non-scoliotic (OR = 3.1 and 3). Adding to the severity index a weighting factor based on coronal OD-HA, for thoracic scoliosis, improved the positive predictive value by 9% and the specificity by 13%. CONCLUSION: Analysis of OD-HA suggests that AIS patients are almost three times more likely to have malalignment compared with a non-scoliotic population. Furthermore, analysis of coronal OD-HA is promising to help the clinician distinguish between stable and progressive thoracic scoliosis.

Can preoperative magnetic resonance imaging be used for sagittal kyphotic flexibility assessment in patients with kyphosis secondary to symptomatic old osteoporotic thoracolumbar fracture?

OBJECTIVE: This study aimed to investigate whether preoperative magnetic resonance imaging (MRI) can be used for sagittal kyphotic (SK) flexibility assessment in patients with kyphosis secondary to symptomatic old osteoporotic thoracolumbar fracture (so-OTLF). METHODS: The authors evaluated the radiographic data of patients with kyphosis secondary to so-OTLF. All patients underwent posterior corrective fusion surgery in the hospital. Spinal sagittal parameters were measured on standing radiographs preoperatively. The regional kyphosis angle (RKA) was also measured on preoperative supine MRI and intraoperative prone radiographs on the surgical frame. The SK flexibility in patients with kyphosis secondary to so-OTLF was defined as the difference from the RKA measured on the standing radiographs to that measured on the intraoperative prone radiographs or preoperative supine MRI. The difference and the correlation between the SK flexibility measured by these two methods were compared and analyzed. RESULTS: Thirty-seven patients were included. The RKA measured on standing radiographs, supine MRI, and intraoperative prone radiographs were 48.0°, 34.4°, and 32.0°, respectively. Compared with the RKA measured in standing position, the RKA measured on supine MRI decreased by 13.6° (95% confidence interval 11.4°-15.8°), whereas that measured on intraoperative prone radiographs decreased by 16.1° (95% confidence interval 13.7°-18.5°). A linear correlation existed between the SK flexibility measured on supine MRI and that measured on intraoperative prone radiographs, with a mean difference of 2.4° (R2 = 0.912, p < 0.001). CONCLUSION: The degree of regional kyphosis deformity was reduced by self-reduction of the intraoperative surgical frame. With a predictive value similar to an intraoperative prone radiograph, preoperative supine MRI can be used for SK flexibility assessment in patients with kyphosis secondary to so-OTLF. The ability to predict the intraoperative degree of regional kyphosis deformity with positioning before an operation may help with surgical planning and patient counseling regarding expectations and risks of surgery.

A Patient-specific Approach to Alignment and Proximal Junctional Kyphosis Risk Assessment in Adult Spinal Deformity Surgery: Development and Validation of a Predictive Tool.

STUDY DESIGN: This was a single-institution, retrospective cohort study. OBJECTIVE: We aimed to develop a predictive model for proximal junctional kyphosis (PJK) severity that considers multiple preoperative variables and modifiable surgical alignment. SUMMARY OF BACKGROUND DATA: PJK is a common complication following adult deformity surgery. Current alignment targets account for age and pelvic incidence but not other risk factors. MATERIALS AND METHODS: This is a single-institution, retrospective cohort study of adult deformity patients with a minimum 2-year follow-up undergoing instrumented fusion between 2009 and 2018. A proportional odds regression model was fit to estimate PJK probability and Hart-International Spine Study Group (ISSG) PJK severity score. Predictors included preoperative Charlson Comorbidity Index, vertebral Hounsfield Units near the upper instrumented vertebrae, pelvic incidence, T1-pelvic angle, and postoperative L1-L4 and L4-S1 lordosis. Predictor effects were assessed using adjusted odds ratios and a nomogram constructed for estimating PJK probability. Bootstrap resampling was used for internal validation. RESULTS: Of 145 patients, 47 (32%) developed PJK. The median PJK severity score was 6 (interquartile range, 4-7.5). After adjusting for predictors, Charlson Comorbidity Index, Hounsfield Units, preoperative T1-pelvic angle, and postoperative L1-L4 and L4-S1 lordosis were significantly associated with PJK severity ( P <0.05). After adjusting for potential overfitting, the model showed acceptable discrimination [ C -statistic (area under the curve)=0.75] and accuracy (Brier score=0.10). CONCLUSIONS: We developed a model to predict PJK probability, adjusted for preoperative alignment, comorbidity burden, vertebral bone density, and modifiable postoperative L1-L4 and L4-S1 lordosis. This approach may help surgeons assess the patient-specific risk of developing PJK and provide a framework for future predictive models assessing PJK risk after adult deformity surgery. LEVEL OF EVIDENCE: Level III.

Assessment of changes in the sagittal plane of the spine in girls with adolescent idiopathic scoliosis using the moire method.

BACKGROUND: The gold standard in the clinical assessment of the extent of scoliosis is the Cobb method but the analysis also covers the changes that occur within the spine and trunk in relation to the transverse and sagittal planes. OBJECTIVE: The study aimed to estimate changes in the sagittal plane of the spine in girls with right-sided thoracic adolescent idiopathic scoliosis. METHODS: The study involved 29 girls with scoliosis (13.6 ± 0.6 years) and 36 healthy girls as the comparison group. The tests included an interview, clinical examination (with the use of Adam's test and the Cobb angle), and examination of shape of the spine surface with the use of the photogrammetric method and the projection moire effect. RESULTS: Lower values of the thoracic kyphosis parameters were found in the scoliosis group. Significant differences were noted for the parameters of the lumbosacral section α (p= 0.02), thoracolumbar section ß (p< 0.001), the upper thoracic section γ (p< 0.001), thoracolumbar and upper thoracic section ß+γ (p< 0.001) and the total size of α+ß+γ (p< 0.001) curvatures. CONCLUSIONS: The study showed that with an increase in the angular value of the thoracic curvature, the thoracic kyphosis decreased.

Accuracy on the preoperative assessment of patients with adolescent idiopathic scoliosis using biplanar low-dose stereoradiography: a comparison with computed tomography.

BACKGROUND: Although computed tomography (CT) is commonly used to diagnose the scoliotic spine in patients with adolescent idiopathic scoliosis (AIS) preoperatively, it is limited by the high radiation and prone scanning position. Recently, a new biplanar stereoradiography (EOS) was used to image the scoliotic spine in an upright posture with significantly less radiation in non-severe AIS subjects. However, its reliability to assess preoperative AIS patients remains unreported. Hence, the purpose of this study is to compare the scoliotic curvature between prone (CT) and upright positions (EOS) in preoperative AIS patients. METHODS: Thirty-three pre-operative AIS patients (mean age:18.4 ± 4.2) were recruited. EOS was used to scan the whole thoracic spine at upright position. Whereas on the same day, a conventional CT scan was used to evaluate the spine in prone position. The three-dimensional reconstruction of EOS and CT of the spine were then generated. Using previous validated techniques, multiple scoliotic parameters in both modalities were determined. The agreement between the two modalities was compared using the Bland-Altman test, whereas the correlation was assessed by the intraclass correlation coefficient (ICC). RESULTS: The mean ICC (prone and upright) of intra-rater/inter-rater reliabilities for the measured parameters were 0.985,0.961/0.969,0.903, respectively. Thoracic Cobb angles, intervertebral wedging and lumbar lordosis correlated significantly between upright EOS imaging radiographs (62.9 ± 9.3°,6.4 ± 2.9° and 48.8 ± 12.4°) and prone CT (47.3 ± 10.0°,5.8 ± 2.7° and 27.9 ± 11.4°; P < 0.001). The apical vertebral wedging and apical intervertebral disc wedging showed a good correlation among the two modalities (upright, 6.5 ± 3.5° and 6.4 ± 2.9°; prone, 6.5 ± 3.6° and 5.8 ± 2.7°; R2 ≥ 0.94; P < 0.01). Similarly, there was significant correlation in apical intervertebral rotation (R2 = 0.834; P < 0.01) between the prone CT (3.4 ± 3.0°) and upright EOS (3.8 ± 3.2°). In addition, the Cobb angle was significantly larger in upright EOS (62.9 ± 9.3°) than in prone CT (47.3 ± 10.0°, P < 0.01) position. There was significant underestimation on scoliotic severity in the prone position when compared with upright position. CONCLUSIONS: Importantly, the image acquisition and reconstruction from EOS can better provide accurate three-dimensional spinal representations of the scoliotic curvature in preoperative AIS patients. Moreover, our findings suggested that scoliotic curvatures in preoperative AIS patients can be largely represented by both imaging modalities despite the difference in body positioning.

Concurrent Validity of Digital Image-based Postural Assessment as a Method for Measuring Thoracic Kyphosis: A Cross-Sectional Study of Healthy Adults.

OBJECTIVE: To analyze the concurrent validity of the Digital Image-based Postural Assessment (DIPA) method for identifying the magnitude and classification of thoracic kyphosis in adults. METHODOLOGY: On the same day and in the same place, thoracic kyphosis was assessed in 68 adults using 2 methods: the DIPA software protocol and radiography. The DIPA software provided angular values of thoracic kyphosis based on trigonometric relations, while with the radiograph, the curvature was calculated using the Cobb method. The following tests were applied in the statistical analysis: Pearson's correlation, Bland-Altman's graphic representation, root mean square error, and receiver operating characteristic (ROC) curve; α = 0.05. The reference angular values for the standard thoracic posture used in DIPA were determined with the ROC curve based on the Cobb angles. RESULTS: The correlation between the angles obtained for thoracic kyphosis using the DIPA and Cobb methods was found to be high (r = 0.813, P < .001), and the accuracy was ±4°. According to Bland-Altman's representation, the magnitudes provided by the DIPA software were in agreement with those of the Cobb method. In reference values for determining the standard posture of the thoracic spine, the ROC curve indicated good accuracy in diagnosing a decrease in thoracic kyphosis (with a value of 33.9°) and excellent accuracy in diagnosing thoracic hyperkyphosis (with a value 39.9°) when using DIPA. CONCLUSION: The DIPA postural assessment method is valid in the sagittal plane for identifying the magnitude of thoracic kyphosis in adults. Furthermore, it is accurate in diagnosing alterations in thoracic kyphosis.

Assessment of Sagittal Spinopelvic Balance in a Population of Normal Chinese Children.

STUDY DESIGN: A retrospective study of 257 normal children at a single center from July 2016 to November 2018 was performed. OBJECTIVE: To evaluate the spinopelvic parameters in a population of normal children and adolescents in mainland China. SUMMARY OF BACKGROUND DATA: Values for sagittal parameters of the spine vary significantly by ages and different population. No study has yet quantified the normal measures for children and adolescents in China, or how these measures compare with other populations. METHODS: Pelvic incidence (PI), sacral slope, pelvic tilt, thoracic kyphosis (TK, T5-T12), lumbar lordosis (LL, L1-S1), and sagittal vertical axis were measured and evaluated by whole spine AP&lateral X-ray images. RESULTS: A total of 257 subjects, including 116 boys (45%) and 141 girls (55%) aged 3 to 12 years, were enrolled. Correlation matrix analysis demonstrated that sagittal balance is strongly correlated with age and Risser sign, including PI, a reported fixed parameter. Further investigation showed that PI could be expressed by the equation PI = 26.243+1.153×age. CONCLUSION: PI was not a fixed but a dynamic parameter in the population under 12-year old. Indeed, PI increases with age and bone maturity in childhood. We also found lower PI, pelvic tilt, and sacral slope compared with published studies of adolescents in other countries. These results may aid in the treatment of patients with spinal deformity, to help them achieve a certain degree of sagittal spinopelvic balance. LEVEL OF EVIDENCE: 2.

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.

Thoracic kyphosis assessment in postmenopausal women: an examination of the Flexicurve method in comparison to radiological methods.

The Flexicurve ruler is an alternative method to radiographs for measuring thoracic kyphosis (curvature), but it is not certain that it is comparable. This study shows that Flexicurve can estimate radiographic vertebral centroid angles with less error than Cobb angles but that its accuracy would be inadequate for most clinical purposes. INTRODUCTION: The Flexicurve ruler provides a non-radiological method of measuring thoracic kyphosis (TK) that has moderately strong correlations with the gold-standard radiographic Cobb angle method, while consistently underestimating the TK angle. Cobb angles can include measurement errors that may contribute to poor agreement, particularly in older populations. The vertebral centroid angle could be a better radiographic reference method for the validation of Flexicurve. Using two separate radiographic measurements of TK, we examined the validity of Flexicurve. We aimed to ascertain the level of agreement between measures and to empirically explore reasons for between-method differences. METHODS: TK angles determined using Flexicurve and radiographic Cobb and vertebral centroid methods were compared using data from 117 healthy postmenopausal women (mean (SD) age 61.4 (7.0) years). Bland and Altman plots were used to assess differences between methods. Age, bone mineral density and body mass index were examined as characteristics that might explain any differences. RESULTS: Flexicurve angles were scaled prior to analysis. There was no statistically significant difference between angles produced by Flexicurve and vertebral centroid methods (MD - 2.16°, 95%CI - 4.35° to 0.03°) although differences increased proportionally with TK angles. Flexicurve angles were significantly smaller than radiographic Cobb angles and depending on the scaling method used, systematic error ranged between - 2.48° and - 5.19°. Age accounts for some of the differences observed (R2 < 0.08, p < 0.005). CONCLUSIONS: TK measured using the Flexicurve shows better agreement with the radiographic vertebral centroid method, but inaccuracy of the Flexicurve increases with increasing angle of kyphosis.

Assessment of fatty infiltration of the multifidus muscle in patients with adolescent idiopathic scoliosis through evaluation by magnetic resonance imaging compared with histological analysis: a diagnostic accuracy study.

To evaluate fat infiltration in the multifidus muscle close to the scoliotic curve as seen in MRI compared with the histological evaluation in patients with adolescent idiopathic scoliosis (AIS). The evaluation of fatty infiltration in the multifidus muscle of patients with AIS by MRI was compared with biopsy. Fatty infiltration was greater in concave side than in the convex side in both MRI (P=0.005) and biopsy evaluation (P=0.026). There was no correlation between the fatty infiltration findings evaluated through MRI and biopsy. The MRI measurements do not express accurately the tissue changes observed in the biopsy.

Comprehensive Assessment of Outcomes From Patients With Severe Early-onset Scoliosis Treated With a Vertebral Column Resection: Results From an SRS Global Outreach Site (FOCOS) in Ghana.

BACKGROUND: Early-onset scoliosis (EOS) remains a challenging pediatric spine condition to manage. Some severe deformities can be managed with a vertebral column resection (VCR), which is fraught with high complication rates and the outcomes have not been well reported. The purpose of this study is to provide an assessment of operative, radiographic, and clinical outcomes from children diagnosed with severe EOS treated with a VCR. METHODS: We performed a retrospective review of prospectively collected data. Basic demographic data was collected along with the diagnosis, procedure performed, FOCOS risk score, blood loss (estimated blood loss), operative time, neuromonitoring events, intraoperative complications, and clinical follow-up. Coronal and sagittal radiographic parameters were measured by the first author. RESULTS: We identified 14 patients with posttuberculosis deformity (n=7) or congenital deformity (n=7) that underwent VCR between 2013 and 2016 (5 female; age, 7.7±3 y; body mass index, 17.7±2.8). There was significant improvement in coronal radiographic parameters (primary curve: 55 to 21 degrees, secondary: 37 to 13 degrees, T1-12 length: 137 to 151 mm, T1-S1 length: 219 to 271 mm, P<0.05) and sagittal parameters (kyphosis: 85 to 41 degrees, compensatory lordosis 56 to 39 degrees, P<0.001). There was no change in chest width, sagittal vertical axis, or pelvic tilt. Mean proximal junctional kyphosis (PJK) angle was 12±9 degrees and distal junctional kyphosis angle was 9±17 degrees. Estimated blood loss was 860±520 mL and operative time was 200±66 minutes. Seven cases had neuromonitoring changes that improved with corrective maneuvers and blood pressure elevation. Three patients required reoperation for junctional breakdown with 1 having a third operation for an infection, while 2 additional patients had evidence of radiographic PJK. CONCLUSIONS: VCR in the setting of EOS has excellent radiographic outcomes but a high complication profile. Half of these cases had neuromonitoring changes intraoperatively that improved without lasting neurological deficit. Three patients had PJK and 1 had an infection requiring reoperation. LEVEL OF EVIDENCE: Level IV-case series.

Thoracic Kyphosis and Lumbar Lordosis Assessment by Radiography and Photogrammetry: A Review of Normative Values and Reliability.

OBJECTIVE: The purpose of this study was to review referential values for thoracic kyphosis and lumbar lordosis for radiography and photogrammetry analysis and search for information about the interrater and intrarater reliability. METHODS: The databases PubMed/Medline and LILACS were searched using the following keywords: radiograph and posture, postural alignment, and photogrammetry or photometry or biophotogrammetry. Studies containing values of thoracic kyphosis and lumbar lordosis or a reliability test assessed by radiography and photogrammetry were selected. Random numbers were generated in MATLAB from each study individually to establish normative values for the thoracic kyphosis and lumbar lordosis for both methods. After that, frequencies (median, first quartile, and third quartile) were obtained in SPSS 20.0 (IBM Corp, Armonk, New York). RESULTS: Twenty-six articles were selected, of which 23 studies contained values for thoracic kyphosis and lumbar lordosis and 10 tested the intra- and interrater reliability of both methods. For the studies with radiography that calculated the angle by the same method of assessment, the mean was 44.07° (4.75) for L1 to L5 and 58.01° (5.75) for L1 to S1, and for T1 to T12 the mean was 48.33° (6.24). Most studies used the intraclass correlation coefficient test, showing strong reliability. CONCLUSION: No concordance among the results for both methods was shown. Also, it was not possible to perform the same procedure with the photogrammetry studies because of the great discrepancy in procedures and angle calculations. To assess the reliability, it is necessary to use the proper statistical test.

Procedures of assessment on the quantification of thoracic kyphosis and lumbar lordosis by radiography and photogrammetry: A literature review.

The quantification of thoracic kyphosis and lumbar lordosis can be assessed in different ways; among them radiography and photogrammetry. However, the assessment procedures are not consistent in the literature for either method. The objective of this study was to conduct a literature review about postural assessment through radiography and photogrammetry, for delineating the procedures for both methods. In total 38 studies were selected by an online search in the MEDLINE and LILACS databases with the keywords: radiograph and posture, postural alignment, photogrammetry or photometry or biophotogrammetry. For the radiographic method, the results showed divergences in arm positioning and in the calculation of thoracic and lumbar angles. The photogrammetry demonstrated differences in relation to the camera, tripod, plumb line and feet positioning, angle calculation, software utilization, and the use of footwear. Standardization is proposed for both methods to help establish normative values and comparisons between diagnoses.

Comparison of low density and high density pedicle screw instrumentation in Lenke 1 adolescent idiopathic scoliosis.

BACKGROUND: The correlation between implant density and deformity correction has not yet led to a precise conclusion in adolescent idiopathic scoliosis (AIS). The aim of this study was to evaluate the effects of low density (LD) and high density (HD) pedicle screw instrumentation in terms of the clinical, radiological and Scoliosis Research Society (SRS)-22 outcomes in Lenke 1 AIS. METHODS: We retrospectively reviewed 62 consecutive Lenke 1 AIS patients who underwent posterior spinal arthrodesis using all-pedicle screw instrumentation with a minimum follow-up of 24 months. The implant density was defined as the number of screws per spinal level fused. Patients were then divided into two groups according to the average implant density for the entire study. The LD group (n = 28) had fewer than 1.61 screws per level, while the HD group (n = 34) had more than 1.61 screws per level. The radiographs were analysed preoperatively, postoperatively and at final follow-up. The perioperative and SRS-22 outcomes were also assessed. Independent sample t tests were used between the two groups. RESULTS: Comparisons between the two groups showed no significant differences in the correction of the main thoracic curve and thoracic kyphosis, blood transfusion, hospital stay, and SRS-22 scores. Compared with the HD group, there was a decreased operating time (278.4 vs. 331.0 min, p = 0.004) and decreased blood loss (823.6 vs. 1010.9 ml, p = 0.048), pedicle screws needed (15.1 vs. 19.6, p < 0.001), and implant costs ($10,191.0 vs. $13,577.3, p = 0.003) in the LD group. CONCLUSIONS: Both low density and high density pedicle screw instrumentation achieved satisfactory deformity correction in Lenke 1 AIS patients. However, the operating time and blood loss were reduced, and the implant costs were decreased with the use of low screw density constructs.

MICROCOMPUTED TOMOGRAPHIC, MORPHOMETRIC, AND HISTOPATHOLOGIC ASSESSMENT OF CONGENITAL BONE MALFORMATIONS IN TWO NEOTROPICAL VIPERIDS.

Congenital malformations have been reported in all classes of vertebrates and may be a determinant of life span and survival. In reptiles, the incidence of congenital malformations can be associated with genetic and environmental causes, including pollution. The characterization of pathological processes involved in the development of congenital malformations of bone in snakes is rare in the literature, but is of great relevance in the field of reptile conservation and environmental health. We describe congenital bone lesions in 50 newborn jararaca (Bothrops jararaca) and 26 South American rattlesnakes (Crotalus durissus terrificus) born from wild-caught pregnant females in Southeastern Brazil. Lesions were evaluated by morphometric quantitative analysis, x-ray microtomography, and histopathologic descriptive analysis. Morphometric analysis showed that jararaca presented more severe axial lesions (kyphosis, scoliosis, and kyphoscoliosis) than rattlesnakes. Female rattlesnakes presented more severe axial lesions than did males. In rattlesnakes, spinal deformities were more frequently diagnosed in the caudal segment of the body. We present x-ray microtomographic assessments and images of malformed snakes (n=9) and characterized novel malformations, such as the agenesis of frontal, parietal, and supraoccipital bones in a jararaca specimen. Histopathologic findings included vertebral body fusion, myositis, coagulation necrosis, and disorganization of periaxial muscle fibers. The new methods and results presented in this study will be useful and informative for future research in pathology, teratology, embryology, and ecotoxicology in snakes.

An assessment of the most reliable method to estimate the sagittal alignment of the cervical spine: analysis of a prospective cohort of 138 cases.

OBJECTIVE Although there is increasing recognition of the importance of cervical spinal sagittal balance, there is a lack of consensus as to the optimal method to accurately assess the cervical sagittal alignment. Cervical alignment is important for surgical decision making. Sagittal balance of the cervical spine is generally assessed using one of two methods; namely, measuring the angle between C-2 and C-7, and drawing a line between C-2 and C-7. Here, the best method to assess sagittal alignment of the cervical spine is investigated. METHODS Data from 138 patients enrolled in a randomized controlled trial (Procon) were analyzed. Two investigators independently measured the angle between C-2 and C-7 by using Harrison's posterior tangent method, and also estimated the shape of the sagittal curve by using a modified Toyama method. The mean angles of each quantitative assessment of the sagittal alignment were calculated and the results were compared. The interrater reliability for both methods was estimated using Cronbach's alpha. RESULTS For both methods the interrater reliability was high: for the posterior tangent method it was 0.907 and for the modified Toyama technique it was 0.984. For a lordotic cervical spine, defined by the modified Toyama method, the mean angle (defined by Harrison's posterior tangent method) was 23.4° ± 9.9° (range 0.4°-52.4°), for a kyphotic cervical spine it was -2.2° ± 9.2° (range -16.1° to 16.9°), and for a straight cervical spine it was 10.5° ± 8.2° (range -11° to 36°). CONCLUSIONS An absolute measurement of the angle between C-2 and C-7 does not unequivocally define the sagittal cervical alignment. As can be seen from the minimum and maximum values, even a positive angle between C-2 and C-7 could be present in a kyphotic spine. For this purpose, the modified Toyama method (drawing a line from the posterior inferior part of the vertebral body of C-2 to the posterior upper part of the vertebral body of C-7 without any measurements) is a better tool for a global assessment of cervical sagittal alignment. Clinical trial registration no.: ISRCTN41681847 ( https://www.isrctn.com ).

Kyphosis index obtained in X-ray and with flexicurve assessment in children and young people / Índice de cifose obtido em radiografia e com o flexicurva na avaliação de crianças e jovens

Abstract Objectives: to assess the concurrent validity of kyphosis index measured in the flexicurve from the correlation of X-rays exams, identifying its accuracy and to assess the thoracic spine in children and young people. Methods: 31 young people at an average age of 11.1±3.4 years were evaluated by digital x-rays: (1) Cobb angle (ÂngCobb), (2) Kyphosis index (KIX), and (3) KIX angle (ÂngKIX). These were measured from the flexicurve design on the millimetric graph paper: (1) Kyphosis index (KIFint), obtained from C7 the intersection of kyphosis-lordosis, (2) Kyphosis index (KIFT12), obtained between C7 and T12, and (3) Kyphosis angle (ÂngKIFint and ÂngKIFT12). Statistical analysis: Correlation to Pearson Moment-Product and t test (α<0.05). Results: the angular values (ÂngKIFint, ÂngKIFT12, ÂngKIX) were underestimated in relation to Cobb angle (p<0.05), correlating only to KIX angle and Cobb angle [r=0.698, p<0.001]. The linear values (KIFint, KIFT12, KIX) were similar ( p>0.05) among themselves, correlating only to KIX and Cobb angle [r=0.698, p<0.001] and KIX angle and KIX [r=1; p<0.001]. Conclusions: the KIX and KIX angle presented as an accurate method and valid to be used in the thoracic kyphosis assessment, although KIFint, KIFT12, KIFint angle and KIFT12 angle showed no correlation to the gold standard and not being indicated to assess the thoracic kyphosis in children and young people.

Resumo Objetivos: avaliar a validade concorrente do índice de cifose mensurado no flexicurva a partir da correlação com exames de Raios-X, identificando sua acurácia, para avaliação da coluna torácica de crianças e jovens. Métodos: 31 jovens com idade média de 11,1±3,4 anos foram avaliados em radiografias digitais: (1) ângulo Cobb (ÂngCobb), (2) índice de cifose (KIX), e (3) ângulo do KIX (ÂngKIX). Foram mensurados a partir do desenho do flexicurva no papel milimetrado: (1) índice de cifose (KIFint), obtido de C7 à intersecção cifose-lordose, (2) índice de cifose (KIFT12), obtido entre C7 e T12, e (3) ângulo dos índices de cifose (ÂngKIFint e ÂngKIFT12). Análise estatística: Correlação Produto-Momento de Pearson e Teste t (α<0,05). Resultados: os valores angulares (ÂngKIFint, ÂngKIFT12, ÂngKIX) foram subestimados em relação ao ÂngCobb (p<0,05), sendo correlacionados apenas o ÂngKIX e ÂngCobb [r=0,698; p<0,001]. Os valores lineares (KIFint, KIFT12, KIX) foram semelhantes (p>0,05) entre si, sendo correlacionados apenas KIX e ÂngCobb [r=0,698; p<0,001] e ÂngKIX e KIX [r=1; p <0,001]. Conclusões: o KIX e ÂngKIX apresentaram-se como um método acurado e válido para ser utilizado na avaliação da cifose torácica, embora os KIFint, KIFT12, ÂngKIFint e ÂngKIFT12 não apresentaram correlação com o padrão ouro, não sendo indicados para a avaliação da cifose torácica de crianças e jovens.

The Assessment of Upright Cervical Spinal Alignment Using Supine MRI Studies.

STUDY DESIGN: This is a prospective, single-centre study. OBJECTIVE: The purpose of this study is researching whether there is a correlation or not between the cervical alignment in the examinations of magnetic resonance imaging (MRI) in lying position and the alignment in the cervical direct radiography and whether the cervical alignment in standing position could be estimated or not through MRI measurements in the supine position. SUMMARY OF BACKGROUND DATA: Cervical spinal alignment is a parameter required for deciding the surgical procedure particularly in patients with cervical myelopathy and deformity. However, cervical alignment angles change according to lying and standing positions. Therefore, the direct standing radiograph is taken as basis for this examination. METHODS: Cervical alignments were measured with 3 different methods with the standing lateral radiographies and lying MRI of 51 patients with cervical disorder. RESULTS: A high correlation was found between the measurements in standing and lying positions for the spinal alignments measured through the Cobb angle and posterior tangent method. It was found that standing Cobb angle (in plain graphy)=Cobb angle (in MRI)×0.489+7.13 and posterior tangent angle (in plain graphy)=posterior tangent angle (in MRI)×0.54+9.37. CONCLUSIONS: It is possible to estimate the spinal alignment in standing position with the measurements of cervical spinal alignment in the MRI at supine position. And this may render having cervical graphy in standing position unnecessary.

Impact of Fatigue on Maintenance of Upright Posture: Dynamic Assessment of Sagittal Spinal Deformity Parameters After Walking 10 Minutes.

STUDY DESIGN: Retrospective analysis of prospectively collected data. OBJECTIVE: To assess global and regional spinal sagittal radiographic parameters in adults with loss of lumbar lordosis ("flatback") before and after walking 10 minutes. SUMMARY OF BACKGROUND DATA: While routine activities of daily living may exacerbate functional disability of spinal sagittal-plane deformity, there is limited understanding of how sagittal parameters and compensatory mechanisms are affected by activity. METHODS: Consecutive adults with "flatback" at a single institution who previously had full-length standing spinal radiographs before and after walking 10 minutes were reviewed. Changes in spinal deformity sagittal parameters before and after walking were evaluated for two groups: Compensated Sagittal Deformity ("Compensated": sagittal vertical axis [SVA] ≤4 cm and pelvic tilt [PT] >20°) and Decompensated Sagittal Deformity ("Decompensated": SVA>4 cm and PT>20°). Intra-group radiographic comparisons were performed with paired Student t tests. RESULTS: One hundred fifty-seven patients (143 females, 14 males; average age 67.9 ±â€Š5.9 yr) met inclusion criteria. Initial average SVA was 1.7 ±â€Š1.2 cm for "Compensated" and 11.5 ±â€Š6.4 cm for "Decompensated." After walking 10 minutes, significant deteriorations in average SVA were observed for all "Decompensated" patients and 84.6% of "Compensated" patients. For both groups, this was accompanied by significant decreases in PT and LL and increases in PI-LL (P <0.01). Thoracic kyphosis increased after walking for only "Decompensated" (P <0.01). For "Compensated," the change in SVA was determined by decreases in PT and LL, while changes in SVA for "Decompensated" were correlated to worsening of all sagittal parameters. CONCLUSION: After walking, compensatory mechanisms to maintain sagittal balance in adults with spinal deformity are less pronounced than when the patient initially presents. This results in significant sagittal decompensation, irrespective of the initial SVA. As we postulate that loss of compensatory mechanisms is due to fatigue on pelvic and spinal extensor muscles, sagittal parameters can be re-evaluated with radiographs obtained after patients walk 10 minutes to unmask a hidden sagittal imbalance in compensated deformities. LEVEL OF EVIDENCE: 3.

Skipped versus consecutive pedicle screw constructs for correction of Lenke 1 curves.

PURPOSE: Thoracic pedicle screws provide superior curve correction to hook and wire constructs in adolescent idiopathic scoliosis, while increasing cost. The number of implants required for best correction and outcome has not yet been determined. METHODS: We retrospectively reviewed pre- and post-operative radiographs and self-reported outcome measures in an age- and curve-matched cohort of 40 patients with Lenke I AIS who underwent selective fusions between T3/4 and L1. Twenty patients were treated with thoracic pedicle screws at every level bilaterally (CON) and 20 patients with screws at every level on the concave side and skipped levels on the convex side of the curve (SKP). All patients had a minimum 2-year follow-up. Radiographs were assessed for coronal and sagittal curvatures, as well as thoracic torsion and vertebral rotation. Health-related quality of life was assessed using the SRS-22 instrument. Instrumentation cost data were collected for each case. RESULTS: Postoperative follow-up averaged 28 months for the CON group and 29 months for the SKP group. No statistically significant differences were found between groups with respect to age and pre- and post-operative radiographic parameters. Both constructs provided acceptable correction of the main thoracic curves (66.9 vs. 66.6 %, CON group and SKP group, respectively; p = 0.92), and spontaneous correction of the proximal thoracic (41.5 vs. 41.1 %; p = 0.92) and thoracolumbar/lumbar curves (54.8 vs. 54.3 %; p = 0.92). No significant difference was found in postoperative SRS-22 scores (96 vs. 94.3; p = 0.34). The CON group cost for instrumentation was significantly higher than the SKP group ($19,500 vs. $13,300; p = 0.002). There was no statistically significant difference in operating room times between groups. CONCLUSION: Both construct types provide excellent coronal correction and sagittal balance, with no significant differences in radiographic findings or clinical outcomes. A significant decrease in cost was found with use of skipped screw constructs.