Sagittal Curvature Research Articles

Reliability of cervical lordosis and global sagittal spinal balance measurements in adolescent idiopathic scoliosis

Radiological reproducibility study. To assess intra and interobserver reliability of radiographic measurements for global sagittal balance parameters and sagittal spine curves, including cervical spine. Sagittal spine balance in adolescent idiopathic scoliosis (AIS) is a main issue and many studies have been reported, showing that coronal and sagittal deformities often involve sagittal cervical unbalance. Global sagittal balance aims to obtain a horizontal gaze and gravity line at top of hips when subject is in a static position, involving adjustment of each spine curvature in the sagittal plane. To our knowledge, no study did use a methodologically validated imaging analysis tool able to appreciate sagittal spine contours and distances in AIS and especially in the cervical region. Lateral full-spine low-dose EOS radiographs were performed in 75 patients divided in three groups (control subjects, AIS, operated AIS). Three observers digitally analyzed twice each radiograph and 11 sagittal measures were collected for each image. Reliability was assessed calculating intraobserver Pearson's r correlation coefficient, interobserver intra-class correlation coefficient (ICC) completed with a two-by-two Bland-Altman plot analysis. This measurement method has shown excellent intra and interobserver reliability in all parameters, sagittal curvatures, pelvic parameters and global sagittal balance. This study validated a simple and efficient tool in AIS sagittal contour analysis. It defined new relevant landmarks allowing to characterize cervical segmental curvatures and cervical involvement in global balance.

Reduction in range of cervical motion on serial long-term follow-up in patients undergoing oblique corpectomy for cervical spondylotic myelopathy

To determine whether motion preservation following oblique cervical corpectomy (OCC) for cervical spondylotic myelopathy (CSM) persists with serial follow-up. We included 28 patients with preoperative and at least two serial follow-up neutral and dynamic cervical spine radiographs who underwent OCC for CSM. Patients with an ossified posterior longitudinal ligament (OPLL) were excluded. Changes in sagittal curvature, segmental and whole spine range of motion (ROM) were measured. Nathan's system graded anterior osteophyte formation. Neurological function was measured by Nurick's grade and modified Japanese Orthopedic Association (JOA) scores. The majority (23 patients) had a single or 2-level corpectomy. The average duration of follow-up was 45 months. The Nurick's grade and the JOA scores showed statistically significant improvements after surgery (p < 0.001). 17% of patients with preoperative lordotic spines had a loss of lordosis at last follow-up, but with no clinical worsening. 77% of the whole spine ROM and 62% of segmental ROM was preserved at last follow-up. The whole spine and segmental ROM decreased by 11.2° and 10.9°, respectively (p ≤ 0.001). Patients with a greater range of segmental movement preoperatively had a statistically greater range of movement at follow-up. The analysis of serial radiographs indicated that the range of movement of the whole spine and the range of movement at the segmental spine levels significantly reduced during the follow-up period. Nathan's grade showed increase in osteophytosis in more than two-thirds of the patients (p ≤ 0.01). The whole spine range of movement at follow-up significantly correlated with Nathan's grade. Although the OCC preserves segmental and whole spine ROM, serial measurements show a progressive decrease in ROM albeit without clinical worsening. The reduction in this ROM is probably related to degenerative ossification of spinal ligaments.

Targeted Cranial Bone Transport Distraction Is Enhanced Using a Novel Device

Targeted Cranial Bone Transport Distraction Is Enhanced Using a Novel Device

Sagittal and meridional radii of curvature for a surface with symmetry of revolution by using a null-screen testing method

An algorithm to compute the sagittal and meridional radii of curvature for a surface of revolution is presented. The sagittal radius is obtained from the surface normal, and the meridional radius is calculated from a function fitted to the derivative of the sagittal curvature by using the surface-normals raw data. A calibration spherical surface is tested by using the null-screen testing method. Experimental results of the spherical surface show that the sagittal and meridional radii of curvature differ by 2.600% and 2.604%, respectively, with respect to the actual radius of the calibration spherical surface.

A multicenter analysis of factors associated with change in height after adolescent idiopathic scoliosis deformity surgery in 447 patients

In the surgical management of adolescent idiopathic scoliosis (AIS), patients are often preoperatively informed that they will gain height as a result of their surgery. However, current estimations conflict significantly and do not have any clinical correlation. The authors developed a formula that would predict postoperative gains in height after deformity correction in AIS. A large, multicenter, prospective database was retrospectively queried for AIS patients with Lenke Type 1, 2, or 3 curves having undergone posterior spinal fusion alone. A univariate and multivariate analysis was performed to identify which factors contributed significantly to changes in height. Four hundred forty-seven patients were included in the series. Factors correlating with changes in postoperative height included: upper thoracic curve magnitude, main thoracic curve magnitude, lumbar curve magnitude, T2-12 kyphosis, T5-12 kyphosis, curve flexibility, number of levels fused, presence of Ponte osteotomies, total preoperative coronal Cobb angle, change in coronal curve magnitude, total preoperative sagittal curvature, change in sagittal curvature, and thoracic curve correction. When combined in a multivariate regression analysis the following variables remained significant: thoracic curve magnitude (p < 0.01), number of levels fused (p < 0.01), change in total sagittal curvature (p < 0.01), and the presence of osteotomies (p = 0.03). The contribution from the thoracic curve magnitude was significantly greater than any of the other parameters identified (R2 = 0.140). Change in height (in cm) = ([thoracic curve magnitude × 0.039] + [number of levels fused × 0.193] - [change in sagittal curvature × 0.033] + [x × 0.375]) - 1.858, where x = 1 if 1 or more osteotomies were performed and x = 0 if no osteotomy was performed. The authors' results suggest that changes in the coronal plane contribute more significantly to height changes than those in the sagittal plane and approximately 0.39 cm of height gain can be expected for each 10° of coronal curve preoperatively. Unfortunately, a significant fraction of the postoperative height changes cannot be predicted by currently measured parameters.

Long-term Improvement after the Athens Protocol for Advanced Keratoconus with Significant Ectasia Progression in the Fellow Eye

ABSTRACT To describe the long-term result of the Athens protocol (custom topography-guided advanced surface ablation followed by riboflavin-UVA collagen crosslinking in the same day) for progressive advanced keratoconus in the left eye, while the fellow right eye first presented with relatively mild keratoconus that was treated with a more conservative therapeutic approach of continuous contact lenses use with the goal for ectasia stabilization. Five years after the Athens protocol, a regression of over 10 D (diopters) was observed on the sagittal curvature with significant regularization of corneal shape and improvement of distance corrected visual acuity (DVCA) in the left eye. The right eye, which was treated more conservatively, had an over 12 D increase on sagittal curvature along with significant distortion of the corneal shape and reduction of DCVA. How to cite this article Siqueira JA, Dias LC, Siqueira R, Valbon B, Santos R, Dawson D, Ambrósio Jr R. Longterm Improvement after the Athens Protocol for Advanced Keratoconus with Significant Ectasia Progression in the Fellow Eye. J Kerat Ect Cor Dis 2013;2(3):143-146.

Specific Sagittal Curve Patterns of Cervical Spine in Adolescent Idiopathic Scoliosis (AIS)

Specific Sagittal Curve Patterns of Cervical Spine in Adolescent Idiopathic Scoliosis (AIS)

Kyphosis and review of the literature.

The term kyphosis is used to describe the spinal curve that results in an abnormally rounded back. Kyphosis may develop due to trauma, developmental anomalies, degenerative disc disease, inflammatory diseases, and infectious diseases and also iatrogenic. The aim of this paper is to review the etiopathognesis and the treatment management of kyphosis. A search in the National Library of Medicine (Pubmed) database using key word 'kyphosis' and was made. For the literature review, papers concerning etiopathogenesis, classification and treatment were selected among these papers. A search in the National Library of Medicine (Pubmed) database using key word 'kyphosis' yielded 7506 papers published between 1916 and 2013. The main papers about kyphosis were congenital, Scheuermann, tumour related, neuromuscular, posttraumatic, infectionrelated, iatrogenic kyphosis. Every patient with kyphosis should be treated based on her/his current state and needs. It should always be remembered that the patients with negative sagittal balance can compensate it with the hip flexion but it is far more difficult to compensate the positive sagittal balance. The main goal of surgery to treat the kyphotic patients is to correct the sagittal curve and also restore a spinal balance within an acceptable range above the hips and knees.

Accuracy and reliability of coronal and sagittal spinal curvature data based on patient-specific three-dimensional models created by the EOS 2D/3D imaging system

Three-dimensional (3D) deformations of the spine are predominantly characterized by two-dimensional (2D) angulation measurements in coronal and sagittal planes, using anteroposterior and lateral X-ray images. For coronal curves, a method originally described by Cobb and for sagittal curves a modified Cobb method are most widely used in practice, and these methods have been shown to exhibit good-to-excellent reliability and reproducibility, carried out either manually or by computer-based tools. Recently, an ultralow radiation dose-integrated radioimaging solution was introduced with special software for realistic 3D visualization and parametric characterization of the spinal column. Comparison of accuracy, correlation of measurement values, intraobserver and interrater reliability of methods by conventional manual 2D and sterEOS 3D measurements in a routine clinical setting. Retrospective nonrandomized study of diagnostic X-ray images created as part of a routine clinical protocol of eligible patients examined at our clinic during a 30-month period between July 2007 and December2009. In total, 201 individuals (170 females, 31 males; mean age, 19.88 years) including 10 healthy athletes with normal spine and patients with adolescent idiopathic scoliosis (175 cases), adult degenerative scoliosis (11 cases), and Scheuermann hyperkyphosis (5 cases). Overall range of coronal curves was between 2.4° and 117.5°. Analysis of accuracy and reliability of measurements were carried out on a group of all patients and in subgroups based on coronal plane deviation: 0° to 10° (Group 1, n=36), 10° to 25° (Group 2, n=25), 25° to 50° (Group 3, n=69), 50° to 75° (Group 4, n=49), and more than 75° (Group 5, n=22). Coronal and sagittal curvature measurements were determined by three experienced examiners, using either traditional 2D methods or automatic measurements based on sterEOS 3D reconstructions. Manual measurements were performed three times, and sterEOS 3D reconstructions and automatic measurements were performed two times by each examiner. Means comparison t test, Pearson bivariate correlation analysis, reliability analysis by intraclass correlation coefficients for intraobserver reproducibility and interrater reliability were performed using SPSS v16.0 software (IBM Corp., Armonk, NY, USA). No funds were received in support of this work. No benefits in any form have been or will be received from a commercial party related directly or indirectly to the subject of this article. In comparison with manual 2D methods, only small and nonsignificant differences were detectable in sterEOS 3D-based curvature data. Intraobserver reliability was excellent for both methods, and interrater reproducibility was consistently higher for sterEOS 3D methods that was found to be unaffected by the magnitude of coronal curves or sagittal plane deviations. This is the first clinical report on EOS 2D/3D system (EOS Imaging, Paris, France) and its sterEOS 3D software, documenting an excellent capability for accurate, reliable, and reproducible spinal curvature measurements.

Clinical validation of coronal and sagittal spinal curve measurements based on three-dimensional vertebra vector parameters

For many decades, visualization and evaluation of three-dimensional (3D) spinal deformities have only been possible by two-dimensional (2D) radiodiagnostic methods, and as a result, characterization and classification were based on 2D terminologies. Recent developments in medical digital imaging and 3D visualization techniques including surface 3D reconstructions opened a chance for a long-sought change in this field. Supported by a 3D Terminology on Spinal Deformities of the Scoliosis Research Society, an approach for 3D measurements and a new 3D classification of scoliosis yielded several compelling concepts on 3D visualization and new proposals for 3D classification in recent years. More recently, a new proposal for visualization and complete 3D evaluation of the spine by 3D vertebra vectors has been introduced by our workgroup, a concept, based on EOS 2D/3D, a groundbreaking new ultralow radiation dose integrated orthopedic imaging device with sterEOS 3D spine reconstruction software. Comparison of accuracy, correlation of measurement values, intraobserver and interrater reliability of methods by conventional manual 2D and vertebra vector-based 3D measurements in a routine clinical setting. Retrospective, nonrandomized study of diagnostic X-ray images created as part of a routine clinical protocol of eligible patients examined at our clinic during a 30-month period between July 2007 and December 2009. In total, 201 individuals (170 females, 31 males; mean age, 19.88 years) including 10 healthy athletes with normal spine and patients with adolescent idiopathic scoliosis (175 cases), adult degenerative scoliosis (11 cases), and Scheuermann hyperkyphosis (5 cases). Overall range of coronal curves was between 2.4 and 117.5°. Analysis of accuracy and reliability of measurements was carried out on a group of all patients and in subgroups based on coronal plane deviation: 0 to 10° (Group 1; n=36), 10 to 25° (Group 2; n=25), 25 to 50° (Group 3; n=69), 50 to 75° (Group 4; n=49), and above 75° (Group 5; n=22). All study subjects were examined by EOS 2D imaging, resulting in anteroposterior (AP) and lateral (LAT) full spine, orthogonal digital X-ray images, in standing position. Conventional coronal and sagittal curvature measurements including sagittal L5 vertebra wedges were determined by 3 experienced examiners, using traditional Cobb methods on EOS 2D AP and LAT images. Vertebra vector-based measurements were performed as published earlier, based on computer-assisted calculations of corresponding spinal curvature. Vertebra vectors were generated by dedicated software from sterEOS 3D spine models reconstructed from EOS 2D images by thesame three examiners. Manual measurements were performed by each examiner, thrice for sterEOS 3D reconstructions and twice for vertebra vector-based measurements. Means comparison ttest, Pearson bivariate correlation analysis, reliability analysis by intraclass correlation coefficients for intraobserver reproducibility and interrater reliability were performed using SPSS v16.0 software. In comparison with manual 2D methods, only small and nonsignificant differences were detectable in vertebra vector-based curvature data for coronal curves and thoracic kyphosis, whereas the found difference in L1-L5 lordosis values was shown to be strongly related to the magnitude of corresponding L5 wedge. Intraobserver reliability was excellent for both methods, and interrater reproducibility was consistently higher for vertebra vector-based methods that was also found to be unaffected by the magnitude of coronal curves or sagittal plane deviations. Vertebra vector-based angulation measurements could fully substitute conventional manual 2D measurements, with similar accuracy and higher intraobserver reliability and interrater reproducibility. Vertebra vectors represent a truly 3D solution for clear and comprehensible 3D visualization of spinal deformities while preserving crucial parametric information for vertebral size, 3D position, orientation, and rotation. The concept of vertebra vectors may serve as a starting point to a valid and clinically useful alternative for a new 3D classification of scoliosis.

3D Ultrasound Imaging for Assessment of Scoliosis

Adolescent idiopathic scoliosis (AIS)is defined as deformity of the spine in coronal plane with more than 10 degrees of Cobb’s angle, which measures from the end-plates of the end vertebral bodies in a standing radiograph. It is accompanied by deformities in the sagittal plane together with axial rotational deformities. About 3.1% children suffer from scoliosis in Hong Kong, and similar number has been reported in other regions. The outcome measure for the treatment of patients with AIS relies heavily on the monitoring of coronal and sagittal curves, progression of deformity, and conservative and surgical management.

Effect of Topographic Cone Location on Outcomes of Corneal Collagen Cross-linking for Keratoconus and Corneal Ectasia

To assess the effect of preoperative topographic cone location on 1-year outcomes of corneal collagen cross-linking (CXL). In this prospective, randomized, controlled clinical trial, 99 eyes (66 keratoconus, 33 ectasia) from 76 patients underwent CXL. Cone location was defined by the coordinates of preoperative maximum keratometry (maximum K) using the anterior sagittal curvature topography map (Pentacam, Oculus Optikgeräte GmbH). Patients were divided into three groups: those with a maximum K located within the central 3-mm (central cone group), 3- to 5-mm (paracentral cone group), and outside the 5-mm (peripheral cone group) optical zones. Topography and visual acuity data were obtained preoperatively and at 1 year. In the combined cohort, maximum K and uncorrected and corrected distance visual acuity significantly improved by -1.60±3.40 diopters (D) (P<.001), -0.08±0.25 logMAR (P=.001), and -0.10±0.18 log-MAR (P<.001), respectively. Comparing cone groups, maximum K decreased by 2.60±4.50 D (P<.001) in the central cone group, 1.10±2.50 D (P=.02) in the paracentral cone group, and 0.40±1.20 D (P=.08) in the peripheral cone group. Differences among groups were statistically significant (P<.001). Uncorrected distance visual acuity improved by -0.07±0.3 logMAR (P=.1) (central cone group), -0.1±0.17 logMAR (P=.004) (paracentral cone group), and -0.1±0.25 logMAR (P=.04) (peripheral cone group). Corrected distance visual acuity improved by -0.14±0.21 logMAR (P<.001) (central cone group), -0.08±0.17 logMAR (P=.01) (paracentral cone group), and -0.08±0.12 logMAR (P=.002) (peripheral cone group). For both UDVA and CDVA outcomes, these differences among groups were not statistically significant. After CXL, more topographic flattening occurs in eyes with centrally located cones and the least flattening effect occurs when the cone is located peripherally. This cone-location effect is found in eyes with both keratoconus and ectasia.

Vertebral Column Resection in Children With Neuromuscular Spine Deformity

Retrospective analysis. To determine, in pediatric patients with neuromuscular deformity undergoing vertebral column resection (VCR), the (1) characteristics of the surgery performed; (2) amount of pelvic obliquity restoration, and coronal and sagittal correction achieved; (3) associated blood loss and complications; and (4) extent to which curve type and VCR approach influenced correction, blood loss, and complications. VCR allows for correction of severe, rigid spinal deformity. This technique has not been previously reported in children with neuromuscular disorders. We retrospectively reviewed the records of 23 children with neuromuscular disorders (mean age, 15 years) and spinal deformities (severe scoliosis, 9; global kyphosis or angular kyphosis, 4; kyphoscoliosis, 10) who underwent VCR. The Student t test was used to compare correction differences (statistical significance, P < 0.05). A mean 1.5 vertebrae (27 thoracic and 6 lumbar) were resected per patient. Significant corrections were achieved in pelvic obliquity (11°, from 19° ± 13° to 8° ± 7°), in major coronal curve (56°, from 94° ± 36° to 38° ± 20°), and in major sagittal curve (46°, from 86° ± 37° to 40° ± 19°). There was no difference in correction between various curve types. VCR was associated with substantial blood loss (mean, 76% [estimated blood loss per total blood volume]), which correlated with patient weight and operating time. Overall, 6 patients experienced major complications: spinal cord injury, pleural effusion requiring chest tube insertion, pneumonia, pancreatitis, deep wound infection, and prominent implant requiring revision surgery. There were no deaths or permanent neurological injuries. VCR achieved significant pelvic obliquity restoration and coronal and sagittal correction in children with neuromuscular disorders and severe, rigid spinal deformity. However, this challenging procedure involves the potential for major complications.

Impact of Prone Surgical Positioning on the Scoliotic Spine

To study the impact of patient-specific prone positioning on the sagittal and coronal curves of scoliotic spines, including the impact of various patient and surgical frame factors. Prone operative positioning has been shown to impact the geometry of various individual spinal segments. Its impact on global spinal geometry and influential factors remains unknown. Lateral and coronal radiographs were acquired of 6 scoliotic patients while standing, prone on a dynamically adjustable surgical frame and intraoperatively on the Relton-Hall frame. Standing lateral bending radiographs were also acquired. Lordosis, kyphosis, and Cobb angles were measured in each position. Personalized finite element models (FEMs), including the spine, ribcage, pelvis, and lower limbs were generated for each patient based on their standing radiographs. The FEM's ability to reproduce prone spinal geometry was evaluated by using different values of intervertebral disc elastic moduli: published, optimized based on lateral bending radiographs and optimized based on prone radiographs. The 6 FEMs were then exploited to study the impact of surgical frame cushion configuration, standing curve magnitudes, and patient weight on spinal geometry changes due to prone positioning. All coronal and sagittal curves decreased in the prone position; averaging 12% in lordosis, 19% in kyphosis, 7%, 14%, and 26%, respectively, for proximal thoracic, main thoracic, and thoracolumbar/lumbar Cobb angles. FEM prone simulations yielded best results when optimized by using the prone position radiographs (Δ<5 degrees for all segmental curves). Lateral bending optimization yielded similar results by using published properties. Surgical frame cushion configuration, standing curve magnitudes, and patient weight all had an important impact on spinal geometries with the exception of thoracic cushion longitudinal position. A strong correlation (R=0.86) was found between standing kyphosis and its reduction in the prone position. Prone positioning results in a reduction of all spinal segmental curves which is dependent on a number of patient and surgical frame factors.

Spinal tuberculosis in children: Retrospective analysis of 124 patients

Background:There is a paucity of report on spinal tuberculosis in children. We report a retrospective analysis of 124 children with TB spine treated over 30 years.Materials and Methods:We retrospectively reviewed 124 children; of cervical (n=36), cervicothoracic (n=4), thoracic (n=53), and lumbar and lumbosacral tuberculosis (n=31) with no skip or multifocal lesions treated between 1971-2004. The age ranged from 2 to 15 years of age with 28 children less than 5 years of age, 58 were between 6 and 10 years, and 38 were over 10 years, 18 had paraplegia of various degrees. Ninety-one children were treated conservatively, while 33 children were subjected to surgery for focal debridement (n=23), posterior interspinous wiring and cementation (n=4), and posterior instrumentation with rods and segmental wiring (n=14). Triple chemotherapy (isoniazid, streptomycin, and PAS) was given for 18 months (3HSPa, 15Hpa) between 1971 and 1975, and triple or quadruple chemotherapy (isoniazid, rifampicin, ethambutol, or pyrazinamide) after 1976 to 2004 for 12 months (12RHZ or 12 RHZE). Some of the children in the current series belonged to the British MRC conservative study patients. The average duration of followup was 5 years and 8 months (range 1.6-20 years).Results:All children attained healed status and showed neural recovery (n=18). The patients attained healed status at 18 months in the first series and at 12 months in the second series after chemotherapy. Spontaneous intercorporal fusion occurred only in 10 (8.06%) of 124 children. Sagittal curve during growth showed three different patterns: Unchanged, decreased, and increased curves. The residual kyphosis was unavoidable in cases with growth plate damage. Kyphosis increased in cases with wedged monovertebra and fused wedged block vertebra, though it was different at different level.Conclusion:The vertebral reformation and curve correction were possible only through the growth plates. The posterior instrumented stabilization alone could correct and/or prevent progress of the kyphosis. However, for active tuberculosis, posterior instrumented stabilization combined with anterior radical surgery should be reserved only for the advanced tuberculosis with instability, rapid progress of kyphosis, and/or unacceptable pre-existing kyphosis, though there is a new trend of prophylactic posterior instrumentation even for the early tuberculosis.

Biomechanical Study of Patient Positioning

The objective of this study was to use finite element model (FEM) simulations and experimental testing to study the relationship between lower limb positioning for surgeries of the spine and changes in sagittal curves. Four volunteers underwent lower limb flexibility and range of motion testing before being placed prone on a new surgical frame where lateral radiographs of their spines were taken in positions of hip flexion (average 48 degrees) and extension (average 13 degrees). Personalized FEMs were created representing each volunteer's spine, rib cage, pelvis, and lower limbs. Optimization of model behavior was performed by adjustment of lower limb muscle initial strains. The FEMs were exploited to examine the impact of more extreme and intermediate lower limb positions; 30 degrees of hip extension to 90 degrees of flexion at intervals of 20 degrees. With increased hip flexion, lordosis and kyphosis decreased to an average of 52% (35 degrees) and 16% (6 degrees), respectively. Personalization of the 4 FEMs allowed reproduction of the experimental results within 5 degrees and their subsequent exploitation showed the linear changes in lordosis and kyphosis between extreme positions decreasing an average of 84% (59 degrees) and 34% (13 degrees) with increased hip flexion. A strong correlation was found between experimental change in lordosis and individual hamstring flexibilities (R=-0.93) which allowed for the development of a predictive equation for lordosis in terms of hip flexion which factors straight leg raise test results. Knowledge gained through this study can be used to improve intraoperative control of sagittal curves through lower limb positioning.

High 10-Year Survival Rate with an Anatomic Cementless Stem (SPS)

BackgroundProximal cementless fixation using anatomic stems reportedly increases femoral fit and avoids stress-shielding. However, thigh pain was reported with the early stem designs. Therefore, a new anatomic cementless stem design was based on an average three-dimensional metaphyseal femoral shape. However, it is unclear whether this stem reduces the incidence of thigh pain.Questions/purposesWe asked whether this stem design was associated with a low incidence of thigh pain and provided durable fixation and high function.MethodsOne hundred seventy-one patients (176 THAs) who had the anatomic proximal hydroxyapatite-coated stem implanted were reviewed. Eleven (6%) patients were lost to followup and 34 (20%) died without revision surgery. We used the Harris hip score (HHS) to assess pain and function. We evaluated femoral stem fixation and stability with the score of Engh et al. and also calculated a 10-year survival analysis. We assessed 126 patients (131 hips) at a mean followup of 10 years (range, 8–11 years)ResultsAt last followup, two patients described slight thigh pain that did not limit their physical activities. All stems appeared radiographically stable and one stem was graded nonintegrated but stable. Five patients had revision surgery: one on the femoral side (for posttraumatic fracture) and four on the acetabular side. Considering stem revision for aseptic loosening as the end point, survivorship was 100% (range, 95.4%–99.9%) at 10 years.ConclusionThis anatomic cementless design using only metaphyseal fixation with a wide mediolateral flare, a sagittal curvature, and torsion, allowed durable proximal stem stability and fixation.Level of EvidenceLevel IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Variation of the Position of the Aorta Relative to a Kyphotic Thoracic Spine

An analysis of computed tomography images of the spine in adult Japanese patients. To evaluate the variation of the position of the aorta relative to a spine with a thoracic kyphotic angle and to verify the safety margin for transpedicular screw fixation. Recent studies have suggested that the aorta is positioned more laterally and posteriorly in patients with idiopathic scoliosis than in normal patients; however, variation of the position of the aorta in thoracic sagittal alignment has not been performed. T4-T12 vertebrae were studied using computer tomography images in 58 Japanese patients (aged 31-90 years) with normal coronal alignment of the spine. Pedicle diameter, pedicle length, chord length, closest distance from the aorta, and pedicle-aorta angle (PAA) were evaluated using a Mann-Whitney U test and Spearman rank correlation analysis. Pedicle diameter showed an increase in size from T4 (4.7 mm) to T12 (8.2 mm), pedicle length had an almost constant size of about 20 mm, and chord length increased from T4 (37.7 mm) to T12 (47.2 mm). Closest distance from the aorta decreased from T4 (29.6 mm) to T6 (24.6 mm) and then increased to T12 (49.3 mm). PAA increased from T4 (31.5°) to T6 (38.6°) and then decreased to T12 (5.0°). Sagittal curvature showed a correlation with PAA, with an increasing sagittal thoracic Cobb angle related to decreases in PAA at the T5 (r = -0.31, P = 0.034), T6 (r = -0.37, P = 0.008), and T7 (r = -0.29, P = 0.036) levels. The descending aorta is positioned more medially at the T5, T6, and T7 levels in patients with a kyphotic spine. These spatial relationships should be considered when planning pedicle screw insertion for a kyphotic spine.

Simultaneous Translation on Two Rods to Treat Adolescent Idiopathic Scoliosis

Retrospective analysis of a consecutive cohort of 62 adolescent patients treated by posterior spinal fusion (PSF) with a minimum follow-up of 2 years. To present sagittal and coronal results of a specific method of reduction: the simultaneous translation on 2 rods (ST2R). The long-term outcome of surgically treated scoliosis is dependent not only on the coronal correction but also on restoration of sagittal curves. Recent publications confirm the moderate correction of thoracic hypokyphosis by posterior instrumentation with hooks or pedicle screws. Radiographic parameters were measured preoperatively and at 6 weeks, 1 year, and last follow-up (between 2 and 7.4 years) in a consecutive cohort of 62 patients with adolescent idiopathic scoliosis (AIS) treated by PSF. All operative procedures were performed by the same surgeon using stable anchorages such as screws or self-stabilizing claws. The screws and claws included a polyaxial-threaded extension, which was fixed to the rod with connecting clamps. Reduction of the deformity was obtained by gradual and alternate tightening of the nuts on all threaded extensions on both rods, which allowed the vertebrae to gradually approach the rods while the translation maneuver was performed. In the coronal plane, the average main curve was reduced from 51° to 16° and maintained 70% of correction at last follow-up. In the sagittal plane, for patients with hypokyphosis (27 cases < 20°), the average kyphosis angle was significantly improved from 9° to 29° and maintained during follow-up (32°) with a mean gain of 23° (P < 0.0001). Only 1 patient reported hypokyphosis (18°) at last follow-up. For patients with normal kyphosis, the average gain was 8°. In a large consecutive cohort, reduction of scoliosis by ST2R is a simple method that allows 70% of correction in the coronal plane, equivalent to screw instrumentations, and a restoration of normal thoracic kyphosis.

Comparison of Anterior and Posterior Elevation, and Sagittal Curvature between Keratoconus and Normal Cornea

Comparison of Anterior and Posterior Elevation, and Sagittal Curvature between Keratoconus and Normal Cornea