Vertebral Geometry Research Articles

Vertebral cortical thickness and cortical bone density: an automated CT assessment - towards enhanced spine segmentation

ABSTRACT In this paper a non-invasive method using routine CT scan to assess the vertebral geometry through normalised Cortical Thickness (CTh) and Cortical Bone Density (CBD) is proposed. This paper aims to propose a new automated method to segment cortical bone and measure its thickness and local density. This method were then used as a tool to compare these parameters between different vertebra models (in-vivo, cadaver and swine) and vertebra levels. An automated technique to segment cortical bone was proposed, assuming a two Gaussian bone density distribution. 42 vertebrae (3 high-thoracic, 3 low-thoracic and 1 lumbar vertebra for each subject) from three sub-groups (human in-vivo, cadaver and swine) were investigated. In the human in-vivo sub-group, the vertebral level was shown to influence normalised CTh and CBD. The CBD was found uniform within all the functional areas of the vertebral body (p > 0.05), while the normalised CTh showed significant differences (p < 0.001). Both CBD and normalised CTh showed significantly different between the inferior articular processes area and the posterior arch area d (p < 0.02 *). In each of the three sub-groups (human in-vivo Vs cadaveric Vs swine), normalised CTh and CBD were found significantly different across most functional areas (p < 0.001 ***). The proposed method offers an automated and accurate way of measuring cortical thickness and cortical bone density. Vertebra level and vertebra function areas were found to have influences on both proposed cortical bone characteristics. The influence of the vertebral level and of the vertebral functional areas on normalised CTh and CBD were reported within in-vivo and two vertebral models. Such a methodology could be used as a tool for image-guided surgery.

Biomechanical Behavior of Injected Cement Spacers versus Traditional Cages in Low-Density Lumbar Spine under Compression Loading.

Background and Objectives: Osteoporosis renders the use of traditional interbody cages potentially dangerous given the high risk of damage in the bone-implant interface. Instead, injected cement spacers can be applied as interbody devices; however, this technique has been mainly used in cervical spine surgery. This study aimed at investigating the biomechanical behavior of cement spacers versus traditional cages in lumbar spine surgery. Materials and Methods: Destructive monotonic axial compression testing was performed on 20 human cadaveric low-density lumbar segments from elderly donors (14 f/6 m, 70.3 ± 12.0 y) treated with either injected cement spacers (n = 10) or traditional cages (n = 10) without posterior instrumentation. Stiffness, failure load and displacement were compared. The effects of bone density, vertebral geometry and spacer contact area were evaluated. Results: Cement spacers demonstrated higher stiffness, significantly smaller displacement (p < 0.001) and a similar failure load compared to traditional cages. In the cage group, stiffness and failure load depended strongly on bone density and vertebral height, whereas failure displacement depended on vertebral anterior height. No such correlations were identified with cement spacers. Conclusions: Cement spacers used in lumbar interbody stabilization provided similar compression strength, significantly smaller failure displacement and a stiffer construct than traditional cages that provided benefits mainly for large and strong vertebrae. Cement stabilization was less sensitive to density and could be more beneficial also for segments with smaller and less dense vertebrae. In contrast to the injection of cement spacers, the optimal insertion of cages into the irregular intervertebral space is challenging and risks damaging bone. Further studies are required to corroborate these findings and the treatment selection thresholds.

A numerical investigation of passive acoustic mapping for monitoring bubble-mediated focused ultrasound treatment of the spinal cord.

Focused ultrasound (FUS) combined with intravenous microbubbles (MBs) has been shown to increase drug delivery to the spinal cord in animal models. Eventual clinical translation of such a technique in the sensitive spinal cord requires robust treatment monitoring to ensure efficacy, localization, safety, and provide key intraprocedural feedback. Here, the use of passive acoustic mapping (PAM) of MB emissions with a spine-specific detector array in the context of transvertebral FUS sonications is investigated in silico. Using computed tomography-derived human vertebral geometry, transvertebral detection of MBs is evaluated over varying source locations with and without phase and amplitude corrections (PACs). The impact of prefocal cavitation is studied by simulating concurrent cavitation events in the canal and pre-laminar region. Spatially sensitive application of phase and amplitude is used to balance signal strengths emanating from different axial depths in combination with multiple dynamic ranges to elicit multisource viewing. Collectively, the results of this study encourage the use of PAM in transvertebral FUS applications with PACs to not only localize sources originating in the spinal canal but also multiple sources of innate amplitude mismatches when corrective methods are applied.

FGF4L2 retrogene copy number is associated with intervertebral disc calcification and vertebral geometry in Nova Scotia Duck Tolling Retrievers

To evaluate the effects of the chondrodystrophy-associated FGF4L2 retrogene on intervertebral disc (IVD) calcification and vertebral geometry. 22 Nova Scotia Duck Tolling Retrievers (NSDTR) with no FGF4L2 retrogene (n = 7, wild-type dogs), 1 retrogene copy (8, heterozygous dogs), or 2 retrogene copies (7, homozygous dogs). Computed tomography (CT) scans of the vertebral column were analyzed using computer-aided design (CAD) software. IVD calcification, vertebral column length, and vertebral geometry of the third cervical (C3), 13th thoracic (T13), and first lumbar (L1) vertebrae were compared. IVD calcification was not found in wild-type dogs. IVD calcification was more frequent in homozygous dogs than heterozygous (P = .008) or wild-type dogs (P < .001) and in heterozygous dogs compared to wild-type dogs (P < .001). Four IVDs were subclinically herniated in 3 dogs (2 homozygous, 1 heterozygous). Calcified IVD had a greater volume and surface area in heterozygous dogs than homozygous dogs. C3 vertebral canal height-to-width ratio was greater in homozygous dogs than heterozygous dogs (P = .044) and wild-type dogs (P = .010). IVD calcification and vertebral geometry can be analyzed using CAD software. The presence of 1 or 2 FGF4L2 copies in the absence of the FGF4L1 retrogene has an additive effect on the number of calcified IVD and a minor effect on vertebral geometry in NSDTR dogs. Data support the use of FGF4L2 phenotyping to reduce clinical disease in segregating breeds and to monitor the introduction of wild-type alleles into fixed breed populations.

New method to apply the lumbar lordosis of standing radiographs to supine CT-based virtual 3D lumbar spine models

Standing radiographs play an important role in the characterization of spinal sagittal alignment, as they depict the spine under physiologic loading conditions. However, there is no commonly available method to apply the lumbar lordosis of standing radiographs to supine CT-based virtual 3D models of the lumbar spine. We aimed to develop a method for the sagittal rigid-body registration of vertebrae to standing radiographs, using the exact geometry reconstructed from CT-data. In a cohort of 50 patients with monosegmental spinal degeneration, segmentation and registration of the lumbar vertebrae and sacrum were performed by two independent investigators. Intersegmental angles and lumbar lordosis were measured both in CT scans and radiographs. Vertebrae were registered using the X-ray module of Materialise Mimics software. Postregistrational midsagittal sections were constructed of the sagittal midplane sections of the registered 3D lumbar spine geometries. Mean Hausdorff distance was measured between corresponding registered vertebral geometries. The registration process minimized the difference between the X-rays’ and postregistrational midsagittal sections’ lordoses. Intra- and inter-rater reliability was excellent based on angle and mean Hausdorff distance measurements. We propose an accessible, accurate, and reproducible method for creating patient-specific 3D geometries of the lumbar spine that accurately represent spinal sagittal alignment in the standing position.

126 CENTRAL ADIPOSITY IS ASSOCIATED WITH INCREASED PREVALENCE OF VERTEBRAL FRACTURES

Abstract Background Increased body weight and obesity are associated with greater bone mineral density (BMD) though effects on fracture risk appear to be site specific. In particular, the relationship between Body Mass Index (BMI), abdominal weight and Vertebral Fractures (VF) is complex. Some studies have found greater incidence of VF's with obesity though results are inconsistent. Recent evidence supports a stronger association between measures of abdominal fat and VF's. We aimed to examine the association between central adiposity and VF's in older Irish adults. Methods Participants were from a large cross-sectional study of older Irish adults (aged &amp;gt;60) attending GP or hospital outpatient services. VF diagnosis was based on self-report (ie. clinical vertebral fracture) so we excluded those with a Mini Mental State Examination (MMSE) &amp;lt; 25. BMD was measured with DXA and patients taking antiresorptive or anabolic therapies were excluded. The relationship of waist hip ratio (a surrogate marker of central adiposity) with VF's was explored in regression models. Results 2055 identified, mean age 69.8 ± 6.3 years (range 60-99), 58.6% female. Vertebral fracture prevalence was 6.3% (n=130). Waist hip ratio was positively associated with presence of a vertebral fracture after adjusting for age, sex, BMI, timed up and go, smoking, serum vitamin D, lumbar spine BMD and steroid use &amp;gt; 3 months (beta: 0.04, P&amp;lt;0.001). Conclusion We identified that central adiposity (as measured by waist/hip ratio) was associated with VF presence independent of several factors including BMI and spine BMD. This suggests that body fat distribution and/or altered bone quality may play a role. Visceral body fat (which is correlated with waist hip ratio) is associated with increased production of adipocytokines, altered vertebral geometry and micro-architecture, increased vertebral bone marrow fat and greater loading forces on the spine, all of which may mediate increased VF risk.

Comparison of morphing techniques to develop subject-specific finite element models of vertebrae

This study compared two morphing techniques (and their serial combination) to create subject-specific finite element models of 15 astronaut vertebrae. Surface deviations of the morphed models were compared against subject geometries extracted from medical images. The optimal morphing process yielded models with minimal difference in root-mean-square (RMS) deviation (C3, 0.52 ± 0.14 mm; T3, 0.34 ± 0.04 mm; L1, 0.59 ± 0.16 mm) of the subject’s vertebral geometry. <1% of model elements failed quality checks and compression simulations ran to completion. This research lays the foundation for the development of subject-specific finite element models to quantify musculoskeletal changes and injury risk from spaceflight.

Finite element modeling and static/dynamic validation of thoracolumbar-pelvic segment

Finite element method is an efficient tool to investigate the biomechanics of human spine. The key to finite element method is to reconstruct a complete and accurate finite element model. In this study, a three-dimensional finite element model of thoracolumbar structure including complete pelvis (T12-pelvis) was built using computed tomography technology. The modeling process has been explained in detailed. During the process of validation, the model was assigned with non-linear material property for static or dynamic analyses. In static analysis, the vertebral geometry parameters of T12-L5, the axial displacement, the posterior disc bulge and the intradiscal pressure of intervertebral disc, range of motion under six loading cases and facet joint forces were obtained and compared with the experimental data. In dynamic analysis, motion segments were loaded with sinusoidal displacement at 1 Hz in the anterior–posterior and axial directions to verify the reaction force. The first-order resonant frequencies in the vertical direction from one motion segment and two motion segments to the entire model were obtained. The study provides a detailed and accurate method of validation to verify the finite element model of thoracolumbar spine.

The prototype BS-II for computer measurement of biomechanical characteristics of the human cadaverous lumbar spine

BackgroundThe new second-generation computer system BS-II (Bio-Spine-II) based on the National Instruments’ development environment has been designed and constructed for evaluating the stability of various surgical fixative methods of the cadaverous lumbar spine (L1–L5). BS-II holds the measured sample using aluminum fixtures and using four computer-controlled stepper motors; it performs a circular movement (warm up of the specimen), programmatically driven extension (back bend), right and left lateral flexion (lateral bend), left and right axial torsion (rotation), and axial compression (pressure). Four strain gauges are used to measure the stiffness of the sample. The movement of individual components (vertebrae) is contactlessly monitored by two CCD (charge couple device) cameras. The obtained data are in digital form continuously stored in the computer memory for further processing.MethodsThe functionality of the equipment was verified on the cadaverous specimen of the human spine. The stiffness of the sample was measured by strain gauges, and the results were processed using linear regression analysis. Movements of vertebrae were determined by circular discs covered with appropriate patterns. The discs have been linked with the respective vertebrae and were contactlessly monitored by two CCD (charge couple device) cameras and evaluated using digital image processing methods and 2D digital FFT (fast Fourier transformation). Direction and displacement of the individual components were determined by the band of the calculated spectrum. The new device BS-II is controlled by a modifiable computer program designed in the National Instruments’ development environment which allows statistical processing of the sample, including its warming up.ResultsThe computer system BS-II for measurement of biomechanical properties of the spine sample was designed. Functionality of the device was verified by implementation of LUMIR XLIF CAGE implant into a cadaver sample of the human spine. Comparison of the rigidity of the intact and stabilized sample is shown in the graphs of article. The achieved results contributed to certification of the implant into the surgical practice.ConclusionThe designed computer BS-II system is designed for biomechanical measurements of the lumbar part of the human spine, especially for verification of surgical fixation methods. The system is based on the knowledge and experience with a manually operated measuring device designed by Palacky University Olomouc. The computer programmatic control allows the user to change the conditions and parameters of the measurement procedure in a planned way, which allows the results to be processed in, among other things, a statistical way.If suitable models are used (3D printing), the BS-II system can be used to verify procedures for surgical stabilization of the spine in the training of future doctors.The obtained data of stiffness and image information are stored in digital form and can be used for next offline sophisticated study of biomechanical properties of specimens (accurate vertebral geometry, statistical processing, 3D printing, etc.).The usefulness of the BS-II system is demonstrated in the case of biomechanical analysis of the implantation of LUMIR XLIF CAGE implant to a human cadaver specimen of the spine.

Eating Behavior Traits, Weight Loss Attempts, and Vertebral Dimensions Among the General Northern Finnish Population.

A population-based birth cohort study. To evaluate the associations of eating behavior traits and weight loss attempts with vertebral size among the general Northern Finnish population. Vertebral fragility fractures are a typical manifestation of osteoporosis, and small vertebral dimensions are a well-established risk factor for vertebral fracturing. Previous studies have associated cognitive eating restraint and diet-induced weight loss with deteriorated bone quality at various skeletal sites, but data on vertebral geometry are lacking. This study of 1338 middle-aged Northern Finns evaluated the associations of eating behavior traits (flexible and rigid cognitive restraint of eating, uncontrolled eating, emotional eating; assessed by the Three-Factor Eating Questionnaire-18) and weight loss attempts (assessed by a separate questionnaire item) with magnetic resonance imaging-derived vertebral cross-sectional area (CSA). Sex-stratified linear regression models were used to analyze the data, taking body mass index, leisure-time physical activity, general diet, smoking, and socioeconomic status as potential confounders. Women with rigid or rigid-and-flexible cognitive eating restraints had 3.2% to 3.4% smaller vertebral CSA than those with no cognitive restraint (P ≤ 0.05). Similarly, the women who reported multiple weight loss attempts in adulthood and midlife had 3.5% smaller vertebral size than those who did not (P = 0.03). Other consistent findings were not obtained from either sex. Rigid cognitive eating restraint and multiple weight loss attempts predict small vertebral size and thus decreased spinal health among middle-aged women, but not among men. Future longitudinal studies should confirm these findings. 3.

NUMERICAL ANALYSIS OF SHORT AND LONG INSTRUMENTATION IN THE TREATMENT OF THORACOLUMBAR FRACTURES CONSIDERING THE LIGAMENTOUS PORTION

ABSTRACT Objective: This study aims to numerically evaluate the surgical treatment of thoracolumbar fractures, comparing the strengths between the long and short fixations using the pedicle of the fractured vertebra, taking into account the supraspinous, intertransverse, and anterior longitudinal ligaments. Methods: A numerical analysis of the techniques of long and short fixation of a thoracolumbar spine fracture was performed using computed tomography images that were converted into three-dimensional models and analyzed through the ANSYS program. The two types of treatments were analyzed considering the tensions generated in the immediate postoperative period, when the fracture has not yet been consolidated. The anterior, posterior, supraspinal and intertransverse longitudinal ligaments were added, in addition to considering different vertebral geometries. Results: Taking into account that the maximum tensile stress of the material used in the metal implant, in the case of titanium, was 960 MPa, the highest tension found in the analysis of the short instrumentation was 346.83 MPa, reaching only 36.13% of the load the material supports, being, therefore, within a safety limit. The analysis performed in the spine with long instrumentation showed the highest tension value of 229.22 MPa. Conclusions: Considering the values found and the resistance of the synthesis material used, the short and long fixation can be considered in the treatment of thoracolumbar fractures with similarity and a good safety coefficient. Level of Evidence III; Case-Control.

Gravidity, Parity, and Vertebral Dimensions in the Northern Finland Birth Cohort 1966.

A population-based birth cohort study. To investigate the association between gravidity, parity, and vertebral geometry among middle-aged women. Vertebral size is a recognized determinant of vertebral fracture risk. Yet, only a few lifestyle factors that influence vertebral size are known. Pregnancy is a labile period that may affect the maternal vertebral size or shape. The lumbar lordosis angle is permanently deepened by pregnancy, but it remains unclear whether vertebral shape or size contribute to this deepened angle. We aimed to investigate whether gravidity and parity were associated with vertebral cross-sectional area (CSA) and height ratio (anterior height to posterior height) among 705 middle-aged women from the Northern Finland Birth Cohort 1966. We measured the corpus of their fourth lumbar vertebra using magnetic resonance imaging of the lumbar spine at the age of 46. Gravidity and parity were elicited using a questionnaire also at the age of 46. Linear regression analysis was used with adjustments for body mass index, vertebral CSA (height ratio models), and vertebral height (CSA models). We also ran a subgroup analysis that did not include nulliparous women, and we compared nulliparous women with grand multiparous women. The models found no statistically significant associations between the predictors and outcomes. Crude and adjusted results were highly similar, and the subgroup analyses provided analogous results. Pregnancy, or even multiple pregnancies, do not seem to have long-term effects on vertebral geometry. In order to enhance the prevention of vertebral fractures, future studies should aim to reveal more lifestyle determinants of vertebral size. 3.

Simulating transvertebral ultrasound propagation with a multi-layered ray acoustics model

The simulation accuracy of transvertebral ultrasound propagation using a multi-layered ray acoustics model based on CT-derived vertebral geometry was investigated through comparison with experimental measurements of pressure fields in ex vivo human vertebral foramen. A spherically focused transducer (5 cm diameter, f-number 1.2, 514 kHz) was geometrically focused to the centre of individual thoracic vertebral foramen, through the posterior bony elements. Transducer propagation paths through the laminae and the spinous processes were tested. Simulation transducer-vertebra configurations were registered to experiment transducer-vertebra configurations, and simulation accuracy of the simulation model was evaluated for predicting maximum transmitted pressure to the canal, voxel pressure in the canal, and focal distortion. Accuracy in predicting maximum transmitted pressure was calculated by vertebra, and it is shown that simulation predicts maximum pressure with a greater degree of accuracy than a vertebra-specific insertion loss. Simulation error in voxel pressure was evaluated using root-mean-square error and cross-correlation, and found to be similar to the water-only case. Simulation accuracy in predicting focal distortion was evaluated by comparing experiment and simulation maximum pressure location and weighted >50% focal volume location. Average simulation error across all measurements and simulations in maximum pressure location and weighted >50% focal volume location were 2.3 mm and 1.5 mm, respectively. These errors are small relative to the dimensions of the transducer focus (4.9 mm full width half maximum), the spinal cord (10 mm diameter), and vertebral canal diameter (15–20 mm diameter). These results suggest that ray acoustics can be applied to simulating transvertebral ultrasound propagation.

Construction of a Statistical Cervical Vertebrae Geometric Model for Children 3-10Years Old.

Cervical spinal injuries of children in motor vehicle crashes have high morbidity and mortality rates. Cervical vertebrae change rapidly in both size and shape during growth. To accurately assess the risk of spinal injury for children of different ages, it is necessary to understand how the spatial geometric features of vertebrae change with the child's age and neck size. In this study, an innovative semi-automated method was developed that can extract and align geometric points from computed tomography scans to accurately represent complex three-dimensional vertebral geometry. Based on these spatial geometric points, a statistical cervical vertebrae geometry model for children aged 3-10 YO was established based on principal component analysis and multivariate regression. According to this model, the vertebra spatial geometries for children of different ages and neck circumferences were represented, and its variation with age were accounted for. Statistical results show that age has a significant effect on anterior-posterior length (APL), transverse process width (TPW), vertebral body circumference (VBC) and height (VBH), whereas the significance of location and its interaction with age effects on these four parameters are different. The VBC and VBH increase more rapidly with age than the APL and TPW. In addition, the APL of C6 and C7 increase significantly faster than that of C3. As for the shape changes with child growth, the inclination angle of the upper surface of the lateral mass for C1 and the tilt angle of the articular process of the articular facet joint for C3-7 increase; and the shape of odontoid process of C2 becomes higher and steeper. This study can provide geometric basis for developing multiple pediatric cervical finite element models and anthropomorphic test devices to further quantify child neck injury risk with different ages and neck geometries.

Morphing the feature-based multi-blocks of normative/healthy vertebral geometries to scoliosis vertebral geometries: development of personalized finite element models

Personalized Finite Element (FE) models and hexahedral elements are preferred for biomechanical investigations. Feature-based multi-block methods are used to develop anatomically accurate personalized FE models with hexahedral mesh. It is tedious to manually construct multi-blocks for large number of geometries on an individual basis to develop personalized FE models. Mesh-morphing method mitigates the aforementioned tediousness in meshing personalized geometries every time, but leads to element warping and loss of geometrical data. Such issues increase in magnitude when normative spine FE model is morphed to scoliosis-affected spinal geometry. The only way to bypass the issue of hex-mesh distortion or loss of geometry as a result of morphing is to rely on manually constructing the multi-blocks for scoliosis-affected spine geometry of each individual, which is time intensive. A method to semi-automate the construction of multi-blocks on the geometry of scoliosis vertebrae from the existing multi-blocks of normative vertebrae is demonstrated in this paper. High-quality hexahedral elements were generated on the scoliosis vertebrae from the morphed multi-blocks of normative vertebrae. Time taken was 3 months to construct the multi-blocks for normative spine and less than a day for scoliosis. Efforts taken to construct multi-blocks on personalized scoliosis spinal geometries are significantly reduced by morphing existing multi-blocks.

Study of the morphometric variations of the neural arch in the lumbar vertebrae in adult human skeleton of North Indian population

Measurement of human vertebral geometry is important for accurate surgical procedures. The aim of this study is to measure the neural ach shape from L1 to L5. All Lumbar dry vertebrae (N = 150) of 30 individuals is measured and analyzed by gender. A Digital Vernier Caliper is used to measure the dimensions of the spinous (SP) and transverse (TP) processes, vertebral canal (VC), laminae, and isthmus. Most of the parameters are greater in males. Isthmus length decreases from L1 to L5 vertebrae in males with left side length greater than that of right in the lumbar region. In lumbar vertebrae transverse process length is increasing from L1 (17.83 mm) to L3 (22.58 mm) then decreasing till L5 (18.70 mm) with right side length more than the left side at L1 to L5. Vertebral Superior Canal Width (VSCW) is increasing more than Vertebral Superior Canal length (VSCL) in lumbar vertebrae. The difference of width and length is increasing from L1 (5.65 mm) to L5 (9.28 mm). The shape of vertebral canal is oval in lumbar vertebrae. In conclusion, the neural arch is systematically asymmetrical and dynamic in shape along the lumbar spine.

A NEW METHOD TO DETERMINE VOLUMETRIC BONE MINERAL DENSITY FROM BI-PLANAR DUAL ENERGY RADIOGRAPHS USING A FINITE ELEMENT MODEL: AN EX-VIVO STUDY

Finite element models (FEMs) derived from QCT-scans were developed to evaluate vertebral strength but QCT scanners limitations are restrictive for routine osteoporotic diagnosis. A new approach considers using bi-planar dual energy (BP2E) X-rays absorptiometry to build vertebral FEM. The purpose was to propose a FEM based on BP2E absorptiometry and to compare the vertebral strength predicted from this model to a QCT-based FEM. About 46 vertebrae were QCT scanned and imaged with BP2E X-rays. Subject-specific vertebral geometry and bone material properties were obtained from both medical imaging techniques to build FEM for each vertebra. Vertebral body volumetric bone mineral density (vBMD) distribution and vertebral strength prediction from the BP2E-based FEM and the QCT-based FEM were compared. A statistical error of 7[Formula: see text]mg/cm3 with a RMSE of 9.6% and a [Formula: see text] of 0.83 were found in the vBMD distribution differences between the BP2E-based and qCT-based FEM. The average vertebral strength was 3321[Formula: see text][Formula: see text] and 3768[Formula: see text][Formula: see text] for the qCT-based and BP2E-based FEM, respectively, with a RMSE of 641[Formula: see text]N and [Formula: see text] of 0.92. This method was developed to estimate vBMD distribution in lumbar vertebrae from a pair of 2D-BMD images and demonstrated to be accurate to personalize the mechanical properties in vitro.

3D Morphometric Analysis of Human Vertebrae C3-T3 Using CT Images Reconstruction

Vertebral morphometry is important for spinal analysis, diseases diagnosis and improved implant designs. New technologies available allow us to develop a simple and efficient process of obtaining accurate data of threedimensional (3D) vertebral geometry to create a wide and comprehensive database of vertebral dimension for further research. The primary aim of this study is to introduce a simple and precise technique of vertebral dimension measurement. The technique involves the segmentation of CT scans of a Caucasian male cadaver’s head and torso specimen to reconstruct 3D images of C1-T3 using 3D imaging processing software (ScanIP Academic, Synopsys Inc.), and 3D modelling software (ANSYS SpaceClaim). A systematic way of defining specific Cartesian coordinate system is done on all reconstructed vertebrae’ images and various standard vertebral parameters are determined accordingly. Finally, the data is compared against previous study to verify the reliability of this method. The results showed similar trend of vertebral parameters dimensions at vertebral level, except that the dimensions obtained from reconstructed model of CT scans are significantly greater than Asian specimen. The technique applied in this study in the measurement of vertebral parameters is reliable and preferred to other earlier previous methods. The greater dimensions obtained from the specimen can be explained by different specimen ethnic origin, as the vertebral parameters of Caucasian population were reported to be larger than Asian population. To support this latter hypothesis and to create more statistically accurate data, further study on more specimens should be carried out.

Conservative treatment in Scheuermann's kyphosis: comparison between lateral curve and variation of the vertebral geometry.

BackgroundConservative treatment in the Scheuermann’s kyphosis obtain, during skeletal growth, remodelling of the deformed vertebras. In a previous paper on Scheuermann’s kyphosis, we have studied the geometry variations of all vertebrae included in the curve, before and after the treatment.The purpose of this study was to confirm the effectiveness of conservative treatment in Scheuermann’s kyphosis and was to evaluate and compare the variation of the vertebral geometry with the curve trend in Cobb degrees, before and after conservative treatment.MethodsFrom a consecutive series of patients, we selected 90 patients with thoracic Scheuermann’s kyphosis, treated using anti-gravity brace: 59 male, 31 female. The mean age at the beginning of the treatment was 14 years.Radiographical measurements were performed on radiographs from a lateral projection, at the beginning (t1) and at the end of the treatment (t5). Vertebral geometry modifications at t1 and t5 were analysed according to the following parameters and evaluated by three independent observers: Anterior wedging angle (ALFA) of the apex vertebra and Posterior wall inclination (APOS) of the limiting lower vertebra. The curve was measured in Cobb degrees.ResultsThe results from our study showed that of the 90 patients with a thoracic curve mean value of Cobb degrees was 57.8 ± 6.0 SD at t1 and 41.3 ± 5.6 SD at t5. The differences between t1(angle at baseline) and t5 (end of treatment) were calculated for Cobb, ALFA and APOS angle and were respectively −16.4 ± 4.5, −6.4 ± 1.4 and −2.7 ± 1.2; tested with paired t-test were significative (p < 0.01). The results of the regression analysis to test the relationship between the three measures for the kyphosis (Cobb degree, ALFA and APOS) showed that the best association was between Cobb t5 and ALFA t5 (p < 0.01) and Cobb t1 and APOS t1 (p < 0.01). No significative association was found between the difference between ALFA and APOS.ConclusionWe sustain that using new parameters to study vertebral remodelling allows us to reach a better comprehension of Scheuermann spine response to anti-gravity brace treatment. Furthermore, the evaluation of the ALFA angle of the apex vertebra confirms to be more reliable than Cobb’s angle because it cannot be affected by the radiological position.

Hyperostosis frontalis interna in postmenopausal women—Possible relation to osteoporosis

ABSTRACTTo improve our understanding of hyperostosis frontalis interna (HFI), we investigated whether HFI was accompanied by changes in the postcranial skeleton. Based on head CT scan analyses, 103 postmenopausal women were divided into controls without HFI and those with HFI, in whom we measured the thickness of frontal, occipital, and parietal bones. Women in the study underwent dual energy x-ray absorptiometry to analyze the bone density of the hip and vertebral region and external geometry of the proximal femora. Additionally, all of the women completed a questionnaire about symptoms and conditions that could be related to HFI. Women with HFI had a significantly higher prevalence of headaches, neurological and psychiatric disorders, and a significantly lower prevalence of having given birth. Increased bone thickness and altered bone structure in women with HFI was localized only on the skull, particularly on the frontal bone, probably due to specific properties of its underlying dura. Bone loss in the postcranial skeleton showed the same pattern in postmenopausal women with HFI as in those without HFI. Recording of HFI in medical records can be helpful in distinguishing whether reported disorders occur as a consequence of HFI or are related to other diseases, but does not appear helpful in identifying women at risk of bone loss.