A new MRI technique for imaging scoliosis in the sagittal plane

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 β (p< 0.001), the upper thoracic section γ (p< 0.001), thoracolumbar and upper thoracic section β+γ (p< 0.001) and the total size of α+β+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.

Association between lumbosacral transitional vertebrae and spinal pathologies based on T2 whole-spine sagittal magnetic resonance imaging

PURPOSE

To assess the association between 4, 5, or 6 lumbar spine vertebrae and the presence of lumbar spinal pathologies.

METHODS

We reviewed all MRI reports and images performed between August 1st, 2018 and July 31st, 2019. Lumbar spine pathologies such as disc herniation, lytic spondylolisthesis, and spinal stenosis were recorded. The reviewer studied the T2 sagittal screening of the entire spine and counted down manually from C2 to T12 on the assumption that there are seven cervical and twelve dorsal vertebrae. We then recorded whether there were four, five, or six lumbar vertebrae.

RESULTS

Our work incorporated a total of 1985 patients for whom T2-weighted entire spine sagittal MR images were obtainable. The study cohort's average age was 52.2 ± 15.9 years, comprising 944 males and 1041 females. One hundred and thirty-three patients (6.7%) had 4 lumbar-type vertebrae; 1799 (90.6%) had 5 lumbar-type vertebrae; and 53 (2.7%) had 6 lumbar-type vertebrae. There was a statistically significant difference between the rates of 6 lumbar-type vertebrae in males versus females (p < 0.05). There was a statistically significant difference with more spinal stenosis patients in the 6 lumbar-type vertebrae compared to the 4 or 5 lumbar-type vertebrae groups (p < 0.001).

CONCLUSION

Our study shows that spinal stenosis is significantly more common in patients with 6 lumbar-type vertebrae.

Correlation of supine MRI and standing radiographs for cervical sagittal balance in myelopathy patients: a cross-sectional study

PURPOSE

Cervical sagittal alignment is correlated with myelopathy severity and used by spinal surgeons for surgical planification. Magnetic resonance imaging (MRI) is the gold standard for the evaluation of cervical myelopathy but may not be for the assessment of cervical sagittal balance compared to X-rays. The objective of this study was to assess the correlation of cervical alignment between supine MRI and standing radiographs in patients with cervical spondylotic myelopathy (CSM).

METHODS

Cobb, Jackson and Harrison methods were used to measure cervical sagittal alignment on supine MRI and standing radiographs of CSM adults. Cervical alignment was divided based on Cobb angle values on lordotic (> 4°), kyphotic (< - 4°) and rectitude (- 4° to 4°). Correlations between radiographic and MRI measurements were determined. Intra- and interobserver reliability were assessed and MRI and X-Ray-measured angles were compared.

RESULTS

One hundred and thirty patients with CSM were reviewed. Correlations of cervical lordosis measures between radiographs and MRI were strong using the Cobb (0.65) and Jackson (0.63) methods, and moderate using the Harrison (0.37) method. Mean cervical lordosis angle was significantly lower on supine MRI compared to standing radiographs for all methods (Cobb 11.6 Rx vs. 9.2 MRI, Jackson 14.6 vs. 11.6, Harrison 23.5 vs. 19.9). Eighteen patients (15.4%) without lordosis on supine MRI presented lordosis on standing radiographs.

CONCLUSION

A substantial proportion of patients has sagittal alignment discrepancies between supine MRI and standing radiographs. Therefore, standing radiographs of the cervical spine should always be included in surgical planning of CSM patients.

Coexisting Spine Lesions on Whole Spine T2 Sagittal MRI in Evaluating Spinal Degenerative Disease

BACKGROUND

Studies have reported on the usefulness of whole spine magnetic resonance imaging (MRI) in evaluating specific diseases such as spinal tuberculosis, spinal trauma, spondyloarthropathies, and multiple myeloma. In studies concerning degenerative spinal disease, sample sizes were small and some did not provide information on how symptomatic coexisting lesions were treated. We evaluated the types and prevalence of coexisting spine lesions found on whole spine T2 sagittal screening performed at the time of routine cervical and lumbar spine MRI and evaluated the efficacy of such screening in degenerative diseases of the cervical and lumbar spine.

METHODS

We reviewed 1,757 and 2,266 consecutive cases where whole spine T2 sagittal screening had been performed with routine cervical and lumbar spine MRI, respectively, in patients with cervical and lumbar spinal degenerative diseases. Coexisting spine lesions were documented and statistical analysis was performed to investigate significant differences according to sex, age, and initial diagnosis. Electronic medical records were reviewed to determine whether additional interventions were necessary following such findings.

RESULTS

We reviewed 1,252 and 1,689 consecutive cases of routine cervical and lumbar spine MRI respectively, with whole spine T2 sagittal screening. Of the 1,252, 419 (33.5%) patients with cervical spinal degenerative disease had coexisting lesions in the thoracolumbar spine. Patients with ligament ossification disease of the cervical spine showed a higher prevalence of coexisting spine lesions. Sixty of the 419 (14.3%) patients with coexisting spine lesions warranted additional intervention or surgical treatment. Four hundred and eighty-one of 1,689 (28.5%) patients with lumbar degenerative disease had coexisting spine lesions in the cervicothoracic spine. Forty-eight of the 481 (10.0%) patients with coexisting spine lesions warranted additional intervention. In both patient groups, older patients showed a significantly higher prevalence of coexisting spine lesions than younger patients.

CONCLUSION

Considering the minimal extra time and cost in performing whole spine screening, its application to routine spine MRI can be considered in evaluating cervical and lumbar spinal degenerative diseases.

Could pelvic parameters determine optimal postoperative thoracic kyphosis in Lenke type 1 AIS patients?

Background

A proper restoration of sagittal alignment is essential in AIS patients, but few studies provided a formula to predict an optimal surgical thoracic kyphosis (TK) gain in adolescent idiopathic scoliosis (AIS) patients. A formula was recently proposed (LL = (PI+TK)/2 + 10) to predict the optimal lumbar lordosis (LL) in adult spinal deformity patients, which has not been validated in adolescents. The aim of this study is to establish a formula with TK and pelvic parameters in normal adolescents and predict an optimal TK with this formula pre- and post-operatively in Lenke 1 AIS patients.

Methods

A total of 60 asymptomatic adolescents were used to validate the proposed formula. The subject was considered to match with the formula, if the difference between the virtual TK and the theoretical TK was less than 10°. Then regression analysis was performed to establish a new formula to predict TK in adolescents. The predictive efficiency of the new formula was also validated in 40 Lenke 1 AIS patients.

Results

Of the 60 asymptomatic adolescents, only 26 (43.33%) asymptomatic adolescents matched with the adjusted formula: TK = 2 × (LL-10)-PI. The paired t test revealed a significantly different theoretical TK (tTK) compared to the virtual TK (41.23 ± 18.29° vs. 24.80 ± 8.75°, P < 0.001). Multiple linear regression showed that TK had a relationship with LL, SS and age (R² = 0.331): TK = − 0.785 × LL-0.843 × SS + 0.858 × age + 3.754. There were 27 (67.50%), 32 (80.00%) and 35 (87.50%) Lenke 1 AIS patients matched this formula preoperatively, postoperatively and at the last follow-up.

Conclusion

Our results revealed that the predictive formula for sagittal alignment for adults was not applicable in adolescents. This study established a new predictive formula for TK based on asymptomatic adolescents. In Lenke 1 AIS patients, post-op TK in 87.5% of patients matched the predictive value, indicating that the new formula can be considered as a reference when making a surgery strategy.

[Magnetic resonance imaging versus DR for whole spine imaging in patients with degenerative spinal disease]

OBJECTIVE

To assess the quality of whole spine images obtained by DR and magnetic resonance imaging (MRI) and analyze the whole spinal imaging sagittal parameters for standing DR and supine MRI.

METHODS

Sixty-one patients aged 49.9∓17.6 years with degenerative spinal disease underwent both standing DR and supine MRI of the whole spine from November, 2010 to March, 2016. The image quality was retrospectively reviewed, and the cervical lordosis (CL), thoracic kyphosis (TK), lumbar lordosis (LL), sacral slope (SS), and sagittal vertical axis (SVA) were measured on the whole spinal lateral DR and middle sagittal MR images.

RESULTS

Both the DR and MR whole spine images had a high quality (100%). The CL, TK, LL, SS, and SVA measured were 28.37mnplus;10.91 °, 29.98mnplus;8.96 °, 45.61mnplus;12.46 °, 34.38mnplus;9.05 °, and 17.20mnplus;26.39 mm on DR images and were 24.34mnplus;9.01 °, 21.22mnplus;8.13 °, 41.45mnplus;12.17 °, 37.45mnplus;8.19 °, and 36.51mnplus;12.44mm on MR images, respectively, showing significant differences in the measurements between the two modalities (P=0.000, 0.000, 0.000, 0.001, and 0.007, respectively). The correlation coefficient between DR and MR images for CL, TK, LL, SS, and SVA were 0.69, 0.68, 0.72, 0.51, and 0.27 (P=0.000, 0.000, 0.000, 0.000, and 0.034, respectively).

CONCLUSION

Both standing DR and supine MR whole spine imaging can provide high-quality images. The CL, TK, LL, SS, and SVA measured on supine MR whole spine images are correlated with those on standing DR images but differ obviously. Supine MR imaging can not substitute standing DR examinations, and comprehensive assessment of degenerative spinal disease needs the combination of the two imaging techniques.

Contour and Angle-Function Based Scoliosis Monitoring: Relaxing the Requirement on Image Quality in the Measurement of Spinal Curvature

PURPOSE

A method for measuring spinal curvature that provides a useful analog to the Cobb angle and is tolerant of degraded image quality is proposed. Conventional methods require a higher standard of discernibility for vertebra features and suffer high variability.

METHODS

Assumption is made that the natural representation of the spine for the purpose of scoliosis monitoring is that of a continuous curved contour rather than a series of discrete vertebral bodies with individual orientations. The angle that a tangent line to this contour makes with the vertical, expressed as a continuous function of height, is proposed as a metric for characterization of the curve. The Cobb angle can be approximated as the difference between the extrema of this function, and details of the function shape can provide additional markers for tracking curve variation and evolution. A method for deriving the angle function from coronal images of the spine is proposed, and both manual and automatic variants of the procedure are described.

RESULTS

The method is applied to conventional coronal radiographs and to magnetic resonance (MR) coronal views derived from volumetric acquisitions of the spine. Included in the latter category is an image exhibiting poor discrimination of vertebra features due to motion artifacts. The method permits extraction of the curve and Cobb angles in all cases.

CONCLUSIONS

Because the spine contour is discernible even in low quality images where vertebral endplates may be obscured or poorly contrasted from surrounding tissue, the approach offers improved reliability, applicability across imaging modalities, and, in the case of x-rays, the possibility of a reduced radiation dose. Moreover, since it relies on larger image features and exploits the continuity of the spine, the contour-based approach is expected to reduce the variability associated with Cobb angle measurement.

MRI May Serve as a Valid Alternative to Standing Radiography in Evaluating the Sagittal Alignment of the Upper Thoracic Spine

STUDY DESIGN

This study is of a retrospective radiographic design.

OBJECTIVE

The objective of the study was to compare supine magnetic resonance images (MRI) with standing x-ray scanning in the evaluation of the sagittal alignment of the upper thoracic spine.

SUMMARY OF BACKGROUND DATA

X-ray films have been reported to be inaccurate in evaluating the proximal thoracic sagittal alignment because of poor visibility of the upper thoracic region. Previous studies have demonstrated the feasibility of supine MRI in evaluating spinal deformities in the coronal plane. However, no study has addressed the use of MRI for evaluating the sagittal alignment of the upper thoracic region.

METHODS

Ninety-six adolescents with idiopathic thoracolumbar/lumbar scoliosis were enrolled. The visibility of the upper thoracic spine landmarks from C7 to T6 in the lateral standing x-ray films was first graded. For patients with moderate or good clarity of the landmarks of each vertebra from C7 to T6 on x-ray films, the vertebral sagittal angles from T1 to T5 and the angle of T2-T5 kyphosis were measured by 3 observers on standing x-ray films and supine MRI images, respectively. Intraclass correlation coefficients were used to determine the intraobserver, interobserver, and method reliability. The paired t test was performed to compare the measurements between the 2 methods.

RESULTS

The visibility of the upper thoracic region in x-ray films was generally unsatisfactory, especially for T1 and T2, whereas all the vertebrae were clear in MRI images. Only 50 patients' x-ray films were graded as moderate or good visibility in the upper thoracic spine. Measurements on MRI images gave excellent intraobserver and interobserver reliability (0.914-0.924 and 0.838-0.920, respectively), which were better than that on x-ray films (0.767-0.891 and 0.713-0.883, respectively). No significant difference was found between the 2 modalities in terms of sagittal angles of T3, T4, and T5 (P=0.680, 0.595, and 0.239, respectively) and T2-T5 kyphosis (P=0.105).

CONCLUSIONS

With excellent measurement reproducibility, a supine MRI image may serve as a valid alternative to a standing x-ray film for the measurement for T3, T4, and T5 sagittal angles and for the evaluation of upper thoracic kyphosis.

Magnetic resonance imaging assessment of degenerative cervical myelopathy: a review of structural changes and measurement techniques

Degenerative cervical myelopathy encompasses a spectrum of age-related structural changes of the cervical spine that result in static and dynamic injury to the spinal cord and collectively represent the most common cause of myelopathy in adults. Although cervical myelopathy is determined clinically, the diagnosis requires confirmation via imaging, and MRI is the preferred modality. Because of the heterogeneity of the condition and evolution of MRI technology, multiple techniques have been developed over the years in an attempt to quantify the degree of baseline severity and potential for neurological recovery. In this review, these techniques are categorized anatomically into those that focus on bone, ligaments, discs, and the spinal cord. In addition, measurements for the cervical spine canal size and sagittal alignment are also described briefly. These tools have resulted collectively in the identification of numerous useful parameters. However, the development of multiple techniques for assessing the same feature, such as cord compression, has also resulted in a number of challenges, including introducing ambiguity in terms of which methods to use and hindering effective comparisons of analysis in the literature. In addition, newer techniques that use advanced MRI are emerging and providing exciting new tools for assessing the spinal cord in patients with degenerative cervical myelopathy.

Upright, prone, and supine spinal morphology and alignment in adolescent idiopathic scoliosis

BACKGROUND

Patients with adolescent idiopathic scoliosis (AIS) are usually investigated by serial imaging studies during the course of treatment, some imaging involves ionizing radiation, and the radiation doses are cumulative. Few studies have addressed the correlation of spinal deformity captured by these different imaging modalities, for which patient positioning are different. To the best of our knowledge, this is the first study to compare the coronal, axial, and sagittal morphology of the scoliotic spine in three different body positions (upright, prone, and supine) and between three different imaging modalities (X-ray, CT, and MRI).

METHODS

Sixty-two AIS patients scheduled for scoliosis surgery, and having undergone standard pre-operative work-up, were included. This work-up included upright full-spine radiographs, supine bending radiographs, supine MRI, and prone CT as is the routine in one of our institutions. In all three positions, Cobb angles, thoracic kyphosis (TK), lumbar lordosis (LL), and vertebral rotation were determined. The relationship among three positions (upright X-ray, prone CT, and supine MRI) was investigated according to the Bland-Altman test, whereas the correlation was described by the intraclass correlation coefficient (ICC).

RESULTS

Thoracic and lumbar Cobb angles correlated significantly between conventional radiographs (68° ± 15° and 44° ± 17°), prone CT (54° ± 15° and 33° ± 15°), and supine MRI (57° ± 14° and 35° ± 16°; ICC ≥0.96; P < 0.001). The thoracic and lumbar apical vertebral rotation showed a good correlation among three positions (upright, 22° ± 12° and 11° ± 13°; prone, 20° ± 9° and 8° ± 11°; supine, 16° ± 11° and 6° ± 14°; ICC ≥0.82; P < 0.001). The TK and LL correlated well among three different positions (TK 26° ± 11°, 22° ± 12°, and 17° ± 10°; P ≤ 0.004; LL 49° ± 12°, 45° ± 11°, and 44° ± 12°; P < 0.006; ICC 0.87 and 0.85).

CONCLUSIONS

Although there is a generalized underestimation of morphological parameters of the scoliotic deformity in the supine and prone positions as compared to the upright position, a significant correlation of these parameters is still evident among different body positions by different imaging modalities. Findings of this study suggest that severity of scoliotic deformity in AIS patients can be largely represented by different imaging modalities despite the difference in body positioning.

Comparison of Sagittal Spinopelvic Alignment in Patients With Ankylosing Spondylitis and Thoracolumbar Fracture

This article is a comparative study. The aim of the study is to investigate the difference of sagittal alignment of the pelvis and spine between patients with thoracolumbar kyphosis secondary to ankylosing spondylitis (AS) and thoracolumbar fracture, and to evaluate the role of sacropelvic component in AS patients' adaption to the changes in sagittal alignment. Advanced stages of AS are often associated with thoracolumbar kyphosis, resulting in an abnormal spinopelvic balance and pelvic morphology, whereas thoracolumbar fractures may lead to major kyphosis with a potential compromise of the spinal canal, which can cause an abnormal spinopelvic balance. Until now, the comparison of that sagittal alignment between AS and thoracolumbar fracture is not found in the literature. This study included 30 cases of AS and 30 cases of thoracolumbar fracture. Sagittal spinal and pelvic parameters were measured from the standing lateral radiograph, and the following 11 radiological parameters were measured, including global kyphosis (GK), thoracic kyphosis (TK), C7 tilt (C7T), sagittal vertical axis (SVA), spino-pelvic angle (SSA), lumbar lordosis (LL), upper arc of lumbar lordosis (ULL), lower arc of lumbar lordosis (LLL), pelvic incidence (PI), sacrum slope (SS), pelvic tilt (PT), and T9 tilt (T9T). Analysis of variance was used in the comparison of each dependent variable between the 2 cohorts. The relationship between sagittal spinal alignment and pelvic morphology of AS patients was determined via Pearson correlation coefficient (r). Compared with the thoracolumbar fracture group, AS patients had significantly lower C7T, SSA, LL, LLL and SS (78.3° ± 9.3° vs 88.0° ± 2.7°, P < 0.001 for C7T; 91.6° ± 22.7° vs 119.1° ± 9.0°, P < 0.001 for SSA; 20.7° ± 21.0° vs 36.3° ± 16.8°, P = 0.001 for LL; 18.1° ± 11.9° vs 29.0° ± 9.7°, P < 0.001 for LLL; and 18.1° ± 11.9° vs 29.0° ± 9.7°, P < 0.001 for SS), whereas in terms of SVA and PT, AS patients had an obviously higher value than those of thoracolumbar fracture patients (94.5 mm ± 58.4  mm vs 8.0 mm ± 23.3  mm, P < 0.001 for SVA; and 26.5° ± 10.3° vs 17.5° ± 6.6°, P < 0.001 for PT). In AS patients, SS were found to be significantly correlated with SVA, SSA, and LL (r = -0.312, P < 0.05 for SVA; r = 0.475, P < 0.05 for SSA; r = 0.809, P < 0.001 for LL). In our study, there were significant differences in sagittal alignment of the pelvis and spine between patients with AS and thoracolumbar fracture, and changes in pelvic morphology compensated more in AS patients for a thoracolumbar kyphosis. These findings may be helpful for better understanding of sagittal alignment in patients with thoracolumbar kyphosis secondary to AS.

How Does the Supine MRI Correlate With Standing Radiographs of Different Curve Severity in Adolescent Idiopathic Scoliosis?

STUDY DESIGN

A retrospective study.

OBJECTIVE

To study how the supine magnetic resonance image (MRI) correlates with standing radiographs of different curve severity in adolescent idiopathic scoliosis (AIS).

SUMMARY OF BACKGROUND DATA

Linear correlation between Cobb angles measured on supine MRI and standing radiographs has been identified. However, the effects of different curve severity on the correlation have not been studied in depth.

METHODS

Girls with AIS with standing radiographs and supine MRI were reviewed. From standing radiographs, all structural and nonstructural Cobb angles were measured. For those with simultaneous lateral radiographs, thoracic kyphosis (TK) and lumbar lordosis (LL) angles were measured. On supine MRI, the coronal Cobb angles, TK and LL were measured accordingly. The coronal Cobb angles were divided into 3 groups based on values measured on standing radiographs: mild group for Cobb angles less than 20°, moderate group for 20° to 40°, and severe group for more than 40°. Correlation was analyzed using scatter plot.

RESULTS

Eighty patients with AIS with 122 coronal curves were reviewed. On standing radiographs, the coronal Cobb angles were 14.7°± 3.2°, 28.2°± 5.1°, and 54.9°± 11.3° for mild, moderate, and severe groups. On supine MRI, the Cobb angles averaged 10.1°± 5.6°, 20.0°± 6.3°, and 49.4 ± 12.3° for each group, respectively. TK were 16.3 ± 9.1° and 11.8 ± 6.1° for radiographs and MRI (P < 0.001), whereas the LL averaged 45.5 ± 12.2° and 39.5 ± 10.5° for radiographs and MRI (P < 0.001). Cobb angles measured on standing radiographs and supine MRI were linearly correlated with the adjusted R being 0.0627, 0.2118, and 0.7999 for the mild, moderate, and severe groups.

CONCLUSION

Cobb angles measured on supine MRI were linearly correlated with Cobb angles measured on standing radiographs and the correlation was more reliable in those with Cobb angles more than 40°. Therefore, the supine MRI could serve as a reliable alternative to standing radiographs in the assessment of Cobb angles more than 40° in AIS.

LEVEL OF EVIDENCE

3.

In vitro comparison of three rifampicin loading methods in a reinforced porous β-tricalcium phosphate scaffold

The antibiotic compound, rifampicin (RFP), was loaded into porous reinforced β-tricalcium phosphate (β-TCP) scaffolds using three different solution adsorption methods. This resulted in drug delivery systems (DDS) generated by vacuum adsorption (VA), dynamic adsorption (DA), and static adsorption (SA). In vitro examination of the drug loading and release profiles of the DDS indicated that the unit mass of RFP loaded into the scaffold by the VA method (0.44 mg/g) was higher than that achieved by SA (0.42 mg/g) or DA (0.38 mg/g) (P < 0.05). The mechanical strength had no significant change after RFP-loading (P > 0.05). Moreover, there were no significant differences among the mechanical strength of three β-TCP DDS generated by loading RFP using SA, DA, and VA (P > 0.05). In vitro release testing showed an initial burst release of RFP from the three different DDS within the first 3 h and in the first 51 h, the cumulative release of RFP from VA-DDS, DA-DDS, and SA-DDS had reached 56.2, 83.6, and 88.6 %, respectively. Complete RFP release had occurred from VA-DDS, DA-DDS, and SA-DDS after 23, 17, and 15 days, respectively. As the VA-DDS method showed improved RFP loading and a more sustained drug release, this method is recommended for solution adsorption drug loading into porous β-TCP scaffolds to form a DDS.

Evaluation of demographic factors affecting predictability of the sacro-femoral-pubic angle in healthy adolescents

The objectives of the present study are to evaluate the correlation between pelvic tilt (PT) and the sacro-femoral-pubic (SFP) angle in Asian healthy adolescents, to provide the normal value of SFP angle as reference data in Asian adolescents, and to clarify whether the predictability of PT could be affected by gender and ontogenesis. In all, 100 girls with a mean age of 12.66 years (range 8-18 years) and 70 boys with a mean age of 13.35 years (range 8-18 years) were recruited in this retrospective study. SFP angles and PT were obtained on long-cassette standing upright radiographs. The subjects were grouped based on age. Independent-sample t-tests were performed to compare age, SFP angle, and PT between genders. In all age groups, the relationship between SFP angle and PT was analyzed by Pearson's correlation analysis and linear regression analysis, respectively. Reliability analysis showed high intra- and inter-observer agreements in PT and SFP, with an intra-class correlation coefficient (ICC) > 0.8. SFP angle averaged 71.64° ± 4.91 in all the normal subjects, of which the mean PT was 72.03°± 4.94 in the female group and 71.09°± 4.83 in the male group. SFP and PT were strongly correlated in all the age groups according to Pearson's correlation analysis. The overall coefficient was 0.679 in girls and 0.584 in boys. The present study is the first to describe the normal value of SFP angle in healthy Asian adolescents to serve as a reference data. In all age groups, SFP angles can be used to predict PT when lateral radiographs do not permit assessment of PT. The predictability of SFP angle for PT was not affected by gender or maturation status.

SOSORT 2012 consensus paper: reducing x-ray exposure in pediatric patients with scoliosis

This 2012 Consensus paper reviews the literature on side effects of x-ray exposure in the pediatric population as it relates to scoliosis evaluation and treatment. Alternative methods of spinal assessment and imaging are reviewed, and strategies for reducing the number of radiographs are developed. Using the Delphi technique, SOSORT members developed consensus statements that describe how often radiographs should be taken in each of the pediatric and adolescent sub-populations.

Do novel cement-type biomaterials reveal ion reactivity that affects cell viability in vitro?

Calcium phosphate bioceramics have been studied as bone filler materials for years and have become a component of many commercial products. It is widely known that surface-reactive biomaterials may cause changes in the concentration of crucial ions in the surrounding environment, thereby affecting cell metabolism and viability. The aim of this study was to produce five cement-type biomaterials and characterize their phase composition using X-ray diffraction method, and porosity and pore size distribution using mercury intrusion porosimeter. We then evaluated ion interactions of the novel biomaterials with the surrounding environment (culture medium). A commercially available bone substitute, HydroSet™ (Stryker®), was used as a reference. MTT and NRU cytotoxicity tests were performed to assess the effect of changes in the concentration of crucial ions (calcium, magnesium, phosphate) on osteoblast metabolism and viability in vitro. Our study clearly indicated that various biomaterials demonstrated different ion reactivity and consequently may cause changes in ion concentration in the local environment. Critically low or high values of calcium, magnesium, and phosphate concentrations in the medium exerted cytotoxic effects on the cultured cells. Moreover, we discovered that the chemical composition of the culture medium had a substantial influence on ion interactions with biomaterials.

Bone graft substitutes currently available in orthopaedic practice: the evidence for their use

We reviewed 59 bone graft substitutes marketed by 17 companies currently available for implantation in the United Kingdom, with the aim of assessing the peer-reviewed literature to facilitate informed decision-making regarding their use in clinical practice. After critical analysis of the literature, only 22 products (37%) had any clinical data. Norian SRS (Synthes), Vitoss (Orthovita), Cortoss (Orthovita) and Alpha-BSM (Etex) had Level I evidence. We question the need for so many different products, especially with limited published clinical evidence for their efficacy, and conclude that there is a considerable need for further prospective randomised trials to facilitate informed decision-making with regard to the use of current and future bone graft substitutes in clinical practice.

Using ultrasound imaging to identify landmarks in vertebra models to assess spinal deformity

Scoliosis is a type of spinal deformity that commonly develops in adolescents. Cobb angle, using the most tilted vertebrae, is the gold standard to assess scoliosis on radiographs. However, regularly taking radiographs introduces harmful ionizing radiation to patients, thus non-ionizing radiation methods have been explored for many years. Ultrasound has been proposed as one of the non-ionizing radiation methods to measure the deformity. This research was divided into two studies: 1) to investigate the reliability and repeatability of a new proposed method to measure Cobb angle; 2) to determine if landmarks can be identified from ultrasound images to measure curvature of spine. Based on the two studies, the feasibility of using ultrasound images to assess spinal deformity will be determined. Thirty-nine radiographs were used in the first study. The new method agreed well with the traditional Cobb method with intraclass correlation coefficient (ICC) value greater than 0.7 in different severity groups, and the average angle difference was 1.6° ± 3.1°. The second study showed laminae and transverse processes could be recognized from ultrasound images. The difference of the width of the laminae between the phantom and the ultrasound image was 0.3 mm. Therefore, it is feasible to use the proposed method and the laminae from the ultrasound images to assess the severity of scoliosis.

Comparison of sagittal spinopelvic alignment in Chinese adolescents with and without idiopathic thoracic scoliosis

STUDY DESIGN

A retrospective radiographical study investigated the sagittal alignment in healthy Chinese girls and Chinese girls with idiopathic thoracic scoliosis (T-AIS).

OBJECTIVE

To evaluate the sagittal alignment of the pelvis and spine in Chinese girls with idiopathic scoliosis and healthy girls and to assess whether the pelvic morphology differed between white and Chinese girls with AIS.

SUMMARY OF BACKGROUND DATA

It has been shown that patients with AIS have an abnormal spinopelvic balance and pelvic morphology. Race is a determinant factor of sagittal spinal alignment and serves as a reminder when planning surgical reconstruction for spinal deformity. Until now, there have been no studies documenting the sagittal lumbosacral spine morphology in Chinese girls with T-AIS.

METHODS

In this study, 95 patients with T-AIS and 33 healthy age-matched adolescents were recruited consecutively. Sagittal spinal and pelvic parameters were measured from the standing lateral radiograph, including thoracic kyphosis (TK), lumbar lordosis (LL), upper arc of LL, lower arc of LL, pelvic incidence (PI), sacrum slope (SS), and pelvic tilt (PT). Analysis of variance was used in the comparison of each dependent variable between patients with AIS and healthy adolescents. The relations between all parameters were determined via Pearson correlation coefficient (r).

RESULTS

For all the sagittal parameters, only the TK and the upper arc of the LL showed significant differences between girls with AIS and healthy girls. The LL, lower arc of the LL, and 3 pelvic parameters were similar for both groups. The TK was found to be strongly correlated with LL and the upper arc of the LL in both groups. However, the TK was not related to the lower arc of the LL, nor were the 3 pelvic parameters in either group. In addition, LL was found to be associated with PI and SS in both groups. The lower arc of the LL was also correlated with PI for both groups. The PI was related to PT and SS in both groups; however, no correlation was found between PT and SS. In this study, the TK (15.7°), SS (35.1°), and PI (44.2°) were found to be significantly lower in Chinese patients with T-AIS than the values reported in the AIS cohort.

CONCLUSION

In our study, the Chinese girls with T-AIS had similar PI, PT, and SS values when compared with the age-matched healthy girls. There were significant differences in pelvic morphology between Chinese and white girls with AIS. These results suggest that race may influence an individual's spinopelvic morphology. Although we have shown that the TK could affect LL through the upper arc of the LL directly, the evaluation of the thoracolumbar morphology of T-AIS before surgery is important for surgical planning.

Injectability and mechanical properties of magnesium phosphate cements

Up to now magnesium phosphate cements are mainly being utilized in wastewater treatment due to their adsorptive properties. Recently they also have been shown to have a high potential as degradable biocements for application as replacement materials for bone defects. In comparison to degradable calcium phosphate cements they have the advantage of setting at neutral pH, which is favorable in biological environment. In this study two parameters of the cement composition, namely powder-to-liquid ratio (PLR) and citrate content, were varied in order to optimize the injectability properties of the cement paste and the mechanical properties of the reaction product. These properties were determined by means of testing setting time and temperature, paste viscosity, and injectability as well as phase composition and compressive strength of the set cements. Best results were obtained, when the cements were prepared with a PLR of 2.5 and a binder liquid consisting of an aqueous solution of 3 mol/l diammonium hydrogen phosphate and 0.5 mol/l diammonium citrate.

Uncoupled neuro-osseous growth in adolescent idiopathic scoliosis? A preliminary study of 90 adolescents with whole-spine three-dimensional magnetic resonance imaging

Previous literatures revealed abnormal cross-sectional morphology of spinal cord in AIS, suggesting the presence of disproportional growth between the neural and skeletal system. No accurate measurement of whole spine by MRI multiplanar reconstruction and their correlation with Cobb angle were studied. In this study, MRI three-dimensional reconstruction of the whole spine was performed in 90 adolescents (49 AIS with thoracic/thoracolumbar curve, and 41 age-matched healthy controls). Measurements of the ratio of anteroposterior (AP) and transverse (TS) diameter of the cord, the concave and convex lateral cord space (LCS) were obtained at the apical level in AIS patients. Cerebellar tonsillar level related to the basion-opsithion line, location of conus medullaris, cord length, vertebral column length, cord/vertebral column length ratio were obtained. All of the same parameters were also measured in healthy controls at matched vertebral levels and their correlations with Cobb angle were made. We notice that AP, TS, AP/TS and LCS ratio were increased in AIS subjects with low-lying position of cerebellar tonsillar level and elevating position of conus medullary when compared with healthy controls (P < 0.01). AP, AP/TS and LCS ratio were correlated significantly with Cobb angle (P < 0.05). Cord length and vertebral column length were not significantly different between AIS and control group. However, cord/vertebral column length ratio was significantly smaller in AIS group (P < 0.01). Cord length, vertebral column length and cord/vertebral column length ratio were not related with age or Cobb angle (P > 0.05). These data suggest the presence of uncoupled neuro-osseous growth along the longitudinal axis of spinal cord with associated morphologic changes of cross-sectional configuration and relative position of the cord. Some changes are significantly relevant with Cobb angle, which may indicate pathogenesis of AIS.

Types and prevalence of coexisting spine lesions on whole spine sagittal MR images in surgical degenerative spinal diseases

PURPOSE

We investigated types and prevalence of coexisting lesions found on whole spine sagittal T2-weighted images (WSST2I) acquired from magnetic resonance imaging (MRI) and evaluated their clinical significance in surgical degenerative spinal diseases.

MATERIALS AND METHODS

Coexisting spinal lesions were investigated using WSST2I from 306 consecutive patients with surgical degenerative spinal diseases. Severity of coexisting lesions was classified into four grades (0-3). Lesions of grade 2 and 3 were defined as "meaningful coexisting spine lesions" (MCSL). Degenerative spinal diseases were classified into three pathologies: simple disc herniation, degenerative spinal stenosis, and ligament ossification disease. The relationships between MCSL, gender, age, and primary spine lesions were analyzed.

RESULTS

MCSL were found in 95 patients: a prevalence of 31.1%. Five out of 95 MCSL were surgically managed. The most common types of MCSL were disc herniation with 13.1% prevalence, followed by degenerative stenosis (9.5%) and ligament ossification diseases (6.8%). Older patients (age >or= 40) showed a significantly higher prevalence of MCSL than younger patients. There was no significant difference between male and female patients. The prevalence of MCSL was significantly higher (52.4%) in ligament ossification diseases than in disc herniation or spinal stenosis.

CONCLUSION

Degenerative spinal diseases showed a high prevalence of MCSL, especially in old ages and ligament ossification diseases. WSST2I is useful for diagnosing coexisting spinal diseases and to avoid missing a significant cord-compressing lesion.

Promotion of bone regeneration by CCN2 incorporated into gelatin hydrogel

CCN family protein 2/connective tissue growth factor (CCN2/CTGF) is a unique molecule that promotes the entire endochondral ossification process and regeneration of damaged articular cartilage. Also, CCN2 has been shown to enhance the adhesion and migration of bone marrow stromal cells as well as the growth and differentiation of osteoblasts; hence, its utility in bone regeneration has been suggested. Here, we evaluated the effect of CCN2 on the regeneration of an intractable bone defect in a rat model. First, we prepared two recombinant CCN2s of different origins, and the one showing the stronger effect on osteoblasts in vitro was selected for further evaluation, based on the result of an in vitro bioassay. Next, to obtain a sustained effect, the recombinant CCN2 was incorporated into gelatin hydrogel that enabled the gradual release of the factor. Evaluation in vivo indicated that CCN2 continued to be released at least for up to 14 days after its incorporation. Application of the gelatin hydrogel-CCN2 complex, together with a collagen scaffold to the bone defect prepared in a rat femur resulted in remarkable induction of osteoblastic mineralization markers within 2 weeks. Finally, distinct enhancement of bone regeneration was observed 3 weeks after the application of the complex. These results confirm the utility of CCN2 in the regeneration of intractable bone defects in vivo when the factor is incorporated into gelatin hydrogel.

Preparation of tricalcium phosphate/calcium pyrophosphate structures via rapid prototyping

Custom made tricalcium phosphate/calcium pyrophosphate bone substitutes with a well-defined architecture were fabricated in this study using 3D powder printing with tricalcium phosphate (TCP) powder and a liquid phase of phosphoric acid. The primary formed matrix of dicalcium phosphate dihydrate (DCPD, brushite) was converted in a second step to calcium pyrophosphate (CPP) by heat treatment in the temperature range 1,100-1,300 degrees C. The structures exhibited compressive strengths between 0.8 MPa and 4 MPa after sintering at 1,100-1,250 degrees C, higher strengths were obtained by increasing the amount of pyrophosphate formed in the matrix due to a post-hardening regime prior sintering as well as by the formation of a glass phase from TCP and calcium pyrophosphate above 1,280 degrees C, which resulted in a strong densification of the samples and compressive strength of >40 MPa.

Postural characteristics of adolescents with idiopathic scoliosis

BACKGROUND

The objectives of this study were to compare the postural characteristics of idiopathic scoliosis (IS) patients with different types of spinal curvature and to compare a motion capture and a sequential digitization technique to estimate the postural characteristics of the IS patients.

METHODS

A total of 57 IS patients underwent a radiological, clinical, and postural geometric evaluations in an upright standing position as part of their regular follow-up. The posteroanterior radiograph of the trunk was used to measure the amplitude of spinal curvature. The postural evaluation was performed using a motion capture and sequential digitization technique providing the necessary 3-dimensional positions of anatomical landmarks. These landmarks were used to calculate postural parameters defining the position and orientation of the pelvis, shoulders, and shoulder blades. These measurements included lateral shift and angular measures of rotation and tilt.

RESULTS

Significant differences in the frontal and transverse planes were found between the right thoracic (RTh), left thoracolumbar, and RTh-left lumbar (RThLL) patients. These characteristics were most prominent in the transverse plane for RTh patients, in the frontal plane for left thoracolumbar patients, and in the frontal and transverse planes for the RThLL lumbar patients. A strong positive intraclass correlation was also found between the parameters estimated with the motion capture system and with the sequential digitization system.

CONCLUSIONS

Unique postural characteristics that are related to the type of the spinal curvature are evident in adolescents who have IS. Further work is necessary to assess how these measures may be used to monitor the progression of the spinal deformity.

CLINICAL RELEVANCE

Quantifying the postural alignment of IS patients using surface anthropometric landmarks provides an opportunity to characterize the unique postural attributes that accompany each type of spinal curvature.

Variations of the position of the cerebellar tonsil in idiopathic scoliotic adolescents with a cobb angle >40 degrees: a magnetic resonance imaging study

STUDY DESIGN

A retrospective study was performed through measurements on MRI images in adolescent idiopathic scoliosis (AIS) patients and age-matched adolescents.

OBJECTIVES

To investigate the position of the cerebellar tonsil in AIS patients with a Cobb angle >40 degrees in comparison with age-matched healthy adolescents and to determine the relationships of the tonsil position with age, sex, curve severity, and curve patterns.

SUMMARY OF BACKGROUND DATA

There have been increasing evidences implying that AIS patients may present with subtle or subclinical neurologic dysfunction and a higher incidence of tonsillar ectopia was documented in AIS patients. However, the tonsil position has not been clearly addressed in AIS patients with a severe curve.

METHODS

According to the method described by Aboulezz et al, measurements of the tonsil position relative to the magnum foramen on magnetic resonance images were performed in 203 AIS patients with a Cobb angle >40 degrees and 86 age-matched healthy adolescents. The inferior displacement of the cerebellar tonsil with an extent within 5 mm was defined as tonsillar ectopia when it located below the magnum foramen. On the basis of measurement results, the incidence of tonsillar ectopia was determined in both AIS and control groups. The associations of tonsillar ectopia with curve severity and curve patterns for AIS patients and the relationships of the tonsil positions with age and gender in all subjects were analyzed.

RESULTS

In AIS patients and healthy controls, the median position of the cerebellar tonsil was 0.8 and 2.9 mm above the magnum foramen, respectively. The incidence of tonsillar ectopia (0-4.8 mm below the magnum foramen) in AIS was found to be significantly higher than healthy adolescents (range 0-1.8 mm vs. 0-4.8 mm below the magnum foramen; ratio 34.5% vs. 5.8%; P < 0.01). No significant correlations were found between the position of the cerebellar tonsil with age or gender in AIS and control subjects. It was shown the position of the cerebellar tonsil was not significantly different among AIS patients with different curve severity. However, it was noted that there was a highest incidence (62.5%) of tonsillar ectopia in atypical scoliotic cases with a double thoracic curve. Additionally, a significantly higher incidence of tonsillar ectopia was found in patients with thoracic or thoracolumbar curves when compared with those with lumbar curves (37.4% vs. 21.6%, P = 0.049).

CONCLUSION

Tonsillar ectopia with the extent >2 mm in AIS patients should be regarded as abnormal. AIS patients had a lower tonsil position and a higher prevalence of tonsillar ectopia than controls, and tonsillar ectopia was found to be associated with curve patterns. It is suggested that a lower position of the cerebellar tonsil might be associated with the etiopathogenesis of AIS and might contribute to subclinical neurologic dysfunction in AIS patients.

Curve correction effect of rigid spinal orthosis in different recumbent positions in adolescent idiopathic scoliosis (AIS): a pilot MRI study

In this pilot cross-sectional study, the effectiveness of rigid spinal orthoses in the correction of spinal curvature of 14 patients with moderate adolescent idiopathic scoliosis (AIS) at different recumbent positions (supine, prone, right and left decubitus) was investigated. Using magnetic resonance (MR) imaging and multi-planar reconstruction technique, evaluation of the scoliotic spine in the coronal, sagittal and axial planes and the effect of spinal orthosis on AIS at different recumbent positions was studied. There was significant reduction of coronal Cobb's angle (p < 0.05) with bracing at all four recumbent positions and the maximal reduction was found in the prone position (18% reduction). The sagittal Cobb's angle was only significantly reduced at the supine position while the axial rotation did not change significantly in all positions.

Demonstration of vertebral and disc mechanical torsion in adolescent idiopathic scoliosis using three-dimensional MR imaging

This study was designed to demonstrate and measure mechanical torsion in patients with adolescent idiopathic scoliosis using three-dimensional magnetic resonance (MR) imaging. Ten patients with adolescent idiopathic scoliosis were imaged with three-dimensional MR imaging, and the data post-processed through multiplanar reconstruction to produce images angled through individual endplates. Transverse rotation was measured at each endplate and these measurements used to calculate the amount of vertebral and disc mechanical torsion present. A test object was imaged in order to validate the measurement technique. Mechanical torsion was demonstrated within the vertebral bodies and discs of the imaged subjects, with vertebral mechanical torsion contributing on average 45% of the overall transverse plane deformity. It is concluded that deformation occurs in the transverse plane within the vertebrae and discs of subjects with idiopathic scoliosis, and a significant proportion of the rotation present in the scoliotic spine occurs as a result of plastic deformation within the vertebrae themselves. We believe that this is the first systematic demonstration of mechanical torsion in idiopathic scoliosis.

Visualisation of the brace effect on the spinal profile in idiopathic scoliosis

We studied the brace effect on the spinal profile in idiopathic scoliosis, using a MR procedure visualising the complete scoliotic spine in any vertical plane, while rotating it 180 degrees on the longitudinal axis of the patient. Thirty-eight female patients (mean age, 14.5 years) were included in the study. Inclusion criteria were an idiopathic scoliosis, a Cobb angle greater than 20 degrees , age of 10-17 years and bracing with a Cheneau brace. The brace effect was studied in 38 thoracic curves. The MR examinations were carried out in direct sequences, with and without brace. A reconstruction algorithm allows visualising the whole spine in vertical projections, with rotational steps of 2 degrees , from -90 degrees to 90 degrees , referred to as MR animation. In various vertical MR projections, the changes of the curves were evaluated by measuring the Cobb angle. Additionally, a translation angle of the apical vertebra was determined, representing the lateral deviation of the apical vertebra from a defined midline. Testing the reproducibility of the Cobb angles, the standard deviation of the intra-individual differences was 1.7 degrees and of the inter-individual differences, 2.1 degrees . For the translation angles, the standard deviation of the intra-individual differences was 0.8 degrees and of the inter-individual differences, 0.9 degrees . With brace the mean Cobb angle of the thoracic curves was significantly reduced in the various vertical MR projections. The mean translation angle was also reduced. MR analysis showed that the brace effect is a translation process, straightening the profile of the scoliotic spine in all vertical planes. MR animation allows visualising the brace effect on the spine in scoliosis based on a 3D data set, without additional radiation exposure. It showed the straightening effect of the brace leading to a flattening of the sagittal spinal profile.

Einfluss unterschiedlicher Anr�hrfl�ssigkeiten auf die mechanischen und mikromorphologischen In-vitro-Eigenschaften von Hydroxylapatitzement

AIM

In reconstructive craniofacial surgery a new synthetic hydroxyapatite cement has been used in the last few years. Tetra- and dicalcium phosphates react with either slow setting aqua bidest. or with faster setting sodium monophosphate solution to hydroxyapatite. The aim of this study was to investigate the two mixing fluids of hydroxyapatite for resulting micromorphology, pressure strength, and interactions with fibroblasts.

MATERIAL AND METHODS

Pressure strength tests of hydroxyapatite cement test samples (n=80) were performed after a setting time of 3 and 24 h. The micromorphology of surfaces of the resulting particles was assessed under an electron microscope. In cell cultures L-929 and HEp2 cells were incubated with test samples and cell growth was assessed by light and electron microscopy.

RESULTS

The test samples mixed with sodium monophosphate solution showed statistically significantly higher values of pressure strength. The resulting pressure strength depended on respective mixing fluids, setting time, and pressure of application. In general, test samples mixed with sodium monophosphate solution showed a more load-stable, homogeneous anorganic matrix whereas test samples mixed with aqua bidest. had a porous microarchitecture which was more fragile. In cell culture the porous structure showed disintegration in cell culture medium.

CONCLUSION

To what extent the two mixing liquids of hydroxyapatite cement influence the resorption and bony substitution has to be shown in further studies.

Sagittal plane analysis of the spine and pelvis in adolescent idiopathic scoliosis according to the coronal curve type

STUDY DESIGN

A retrospective study investigated the sagittal alignment in adolescent idiopathic scoliosis (AIS).

OBJECTIVE

To evaluate the sagittal alignment of the spine and pelvis in adolescent idiopathic scoliosis on the basis of curve type.

SUMMARY OF BACKGROUND DATA

The relation between the spine and pelvis highly influences the sagittal balance in adults. However, the sagittal alignment of the spine and pelvis in adolescent idiopathic scoliosis is poorly defined in the literature.

METHODS

Five sagittal parameters were evaluated on lateral radiographs of 160 patients with adolescent idiopathic scoliosis: thoracic kyphosis, lumbar lordosis, sacral slope, pelvic tilt, and pelvic incidence. The patients were classified according to their coronal curve type. Analysis of variance was used to compare the parameters between the curve types, and Pearson coefficients were used to investigate the relation between all parameters (alpha = 0.05).

RESULTS

The thoracic kyphosis was significantly lower for King I, II, and III curves than for lumbar curves. The lumbar lordosis was higher for lumbar curves, although not significantly. No significant change between the groups was observed for the sacral slope, pelvic tilt, or pelvic incidence. The pelvic incidence was significantly correlated with the lumbar lordosis, sacral slope, and pelvic tilt for all the groups. The lumbar lordosis was strongly related to the sacral slope in all cases, but not with the thoracic kyphosis, except in the case of thoracolumbar curves.

CONCLUSIONS

Thoracic kyphosis depended mostly on the spinal deformity, whereas lumbar lordosis was influenced mainly by the pelvic configuration. The scoliotic curve type was not associated with a specific pattern of sagittal pelvic morphology and balance. The pelvic incidence found in this study was significantly higher than that reported in the literature for normal adolescents. The role of the pelvic incidence in the pathogenesis of adolescent idiopathic scoliosis needs to be explored in a longitudinal study involving patients with adolescent idiopathic scoliosis and normal adolescents.