Dino Colo

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

BackgroundPatients 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).MethodsSixty-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).ResultsThoracic 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).ConclusionsAlthough 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.

Anterior Spinal Overgrowth Is the Result of the Scoliotic Mechanism and Is Located in the Disc

Study Design. Cross-sectional study. Objective. To investigate the presence and magnitude of anterior spinal overgrowth in neuromuscular scoliosis and compare this with the same measurements in idiopathic scoliosis and healthy spines. Summary of Background Data. Anterior spinal overgrowth has been described as a potential driver for the onset and progression of adolescent idiopathic scoliosis (AIS). Whether this anterior overgrowth is specific for AIS or also present in nonidiopathic scoliosis has not been reported. Methods. Supine computed tomography (CT) scans of thirty AIS patients (thoracic Cobb 21–81°), thirty neuromuscular (NM) scoliotic patients (thoracic Cobb 19–101°) and 30 nonscoliotic controls were used. The difference in length in per cents between the anterior and posterior side {[(&Dgr;A-P)/P]*100%, abbreviated to A-P%} of each vertebral body and intervertebral disc, and between the anterior side of the spine and the spinal canal (A-C%) were determined. Results. The A-P% of the thoracic curves did not differ between the AIS (+1.2 ± 2.2%) and NM patients (+0.9 ± 4.1%, P = 0.663), both did differ, however, from the same measurements in controls (–3.0 ± 1.6%; P < 0.001) and correlated linearly with the Cobb angle (AIS r = 0.678, NM r = 0.687). Additional anterior length was caused by anterior elongation of the discs (AIS: A-P% disc +17.5 ± 12.7% vs. A-P% body –2.5 ± 2.6%; P < 0.001, NM: A-P% disc +19.1 ± 18.0% vs. A-P% body –3.5 ± 5.1%; P < 0.001). The A-C% T1-S1 in AIS and NM patients were similar (+7.9 ± 1.8% and +8.7 ± 4.0%, P = 0.273), but differed from the controls (+4.2 ± 3.3%; P < 0.001). Conclusion. So called anterior overgrowth has been postulated as a possible cause for idiopathic scoliosis, but apparently it occurs in scoliosis with a known origin as well. This suggests that it is part of a more generalized scoliotic mechanism, rather than its cause. The fact that the intervertebral discs contribute more to this increased anterior length than the vertebral bodies suggests an adaptation to altered loading, rather than a primary growth disturbance. Level of Evidence: 4

Asymmetry of the Vertebral Body and Pedicles in the True Transverse Plane in Adolescent Idiopathic Scoliosis: A CT-Based Study.

STUDY DESIGN Cross-sectional. OBJECTIVES To quantify the asymmetry of the vertebral bodies and pedicles in the true transverse plane in adolescent idiopathic scoliosis (AIS) and to compare this with normal anatomy. SUMMARY OF BACKGROUND DATA There is an ongoing debate about the existence and magnitude of the vertebral body and pedicle asymmetry in AIS and whether this is an expression of a primary growth disturbance, or secondary to asymmetrical loading. METHODS Vertebral body asymmetry, defined as left-right overlap of the vertebral endplates (ie, 100%: perfect symmetry, 0%: complete asymmetry) was evaluated in the true transverse plane on CT scans of 77 AIS patients and 32 non-scoliotic controls. Additionally, the pedicle width, length, and angle and the length of the ideal screw trajectory were calculated. RESULTS Scoliotic vertebrae were on average more asymmetric than controls (thoracic: AIS 96.0% vs. controls 96.4%; p = .005, lumbar: 95.8% vs. 97.2%; p < .001) and more pronounced around the thoracic apex (95.8%) than at the end vertebrae (96.3%; p = .031). In the thoracic apex; the concave pedicle was thinner (4.5 vs. 5.4 mm; p < .001) and longer (20.9 vs. 17.9 mm; p < .001), the length of the ideal screw trajectory was longer (43.0 vs. 37.3 mm; p < .001), and the transverse pedicle angle was greater (12.3° vs. 5.7°; p < .001) than the convex one. The axial rotation showed no clear correlation with the asymmetry. CONCLUSIONS Even in non-scoliotic controls is a degree of vertebral body and pedicle asymmetry, but scoliotic vertebrae showed slightly more asymmetry, mostly around the thoracic apex. In contrast to the existing literature, there is no major asymmetry in the true transverse plane in AIS and no uniform relation between the axial rotation and vertebral asymmetry could be observed in these moderate to severe patients, suggesting that asymmetrical vertebral growth does not initiate rotation, but rather follows it as a secondary phenomenon. LEVEL OF EVIDENCE Level 4.STUDY DESIGN Cross-sectional. OBJECTIVES To quantify the asymmetry of the vertebral bodies and pedicles in the true transverse plane in adolescent idiopathic scoliosis (AIS) and to compare this with normal anatomy. There is an ongoing debate about the existence and magnitude of the vertebral body and pedicle asymmetry in AIS and whether this is an expression of a primary growth disturbance, or secondary to asymmetrical loading. METHODS Vertebral body asymmetry, defined as left-right overlap of the vertebral endplates (ie, 100%: perfect symmetry, 0%: complete asymmetry) was evaluated in the true transverse plane on CT scans of 77 AIS patients and 32 non-scoliotic controls. Additionally, the pedicle width, length, and angle and the length of the ideal screw trajectory were calculated. RESULTS Scoliotic vertebrae were on average more asymmetric than controls (thoracic: AIS 96.0% vs. controls 96.4%; p =.005, lumbar: 95.8% vs. 97.2%; p <.001) and more pronounced around the thoracic apex (95.8%) than at the end vertebrae (96.3%; p =.031). In the thoracic apex; the concave pedicle was thinner (4.5 vs. 5.4 mm; p <.001) and longer (20.9 vs. 17.9 mm; p <.001), the length of the ideal screw trajectory was longer (43.0 vs. 37.3 mm; p <.001), and the transverse pedicle angle was greater (12.3° vs. 5.7°; p <.001) than the convex one. The axial rotation showed no clear correlation with the asymmetry. CONCLUSIONS Even in non-scoliotic controls is a degree of vertebral body and pedicle asymmetry, but scoliotic vertebrae showed slightly more asymmetry, mostly around the thoracic apex. In contrast to the existing literature, there is no major asymmetry in the true transverse plane in AIS and no uniform relation between the axial rotation and vertebral asymmetry could be observed in these moderate to severe patients, suggesting that asymmetrical vertebral growth does not initiate rotation, but rather follows it as a secondary phenomenon. LEVEL OF EVIDENCE Level 4.

The Height-Width-Depth Ratios of the Intervertebral Discs and Vertebral Bodies in Adolescent Idiopathic Scoliosis vs Controls in a Chinese Population

Adolescent idiopathic scoliosis (AIS) patients have been reported to be taller and more slender than normal controls, suggesting less mechanical stiffness of their trunk and spine. For assessment of mechanical stiffness, to our best knowledge this is the first to study height-width-depth relations at the level of the individual vertebra and disc in 3-D and to evaluate its relation with the Cobb angle severity. A unique series of high-resolution pre-operative computed tomographic (CT) scans of a total of 105 Chinese patients with moderate to severe AIS and 11 age-matched non-scoliotic controls were used for this study. It was found that some geometric relations differed between primary thoracic curves, secondary curves and normal controls at the individual affected vertebra and disc level. The scoliotic discs in the primary curves were relatively more slender (taller and thinner) than in secondary curves and as compared to controls. In the lumbar spinal area, the vertebral bodies were more slender in the primary as well as secondary AIS curves as compared to the controls. Therefore, if all material properties remain the same, our finding indicates that scoliotic spines may be mechanically less stiff than normal spines. No significant correlation between any of the measures and Cobb angle severity was found.

Orthopaedic manifestations within the 22q11.2 Deletion syndrome: A systematic review

The 22q11.2 Deletion Syndrome (22q11.2DS) is the most common microdeletion syndrome with an estimated prevalence of 1:4,000 live births. 22q11.2DS is known to have wide phenotypic variability, including orthopaedic manifestations. The purpose of this systematic review is to increase the awareness of orthopaedic manifestations associated with 22q11.2DS. This systematic review was performed according to the PRISMA Guidelines. Original epidemiological studies on the prevalence of orthopaedic manifestations within 22q11.2DS were systematically searched for in PubMed and EMBASE. The included articles were scored according to a risk‐of‐bias tool, a best‐evidence synthesis was performed and the prevalence data was extracted. Sixty‐nine published manuscripts described 58 orthopaedic manifestations in a total of 6,055 patients. The prevalence of at least one cervical or occipital anomaly is 90.5–100% (strong evidence). Fourteen studies (n = 2,264) revealed moderate evidence for a wide scoliosis prevalence of 0.6–60%. Two studies demonstrated that 5–6.4% of all 22q11.2DS patients required surgical scoliosis correction. Fifteen studies (n = 2,115) reported a 1.1–13.3% prevalence of clubfoot with moderate evidence. Other reported orthopaedic manifestations are patellar dislocation (10–20%), juvenile rheumatic arthritis (3.75%), impaired growth and skeletal anomalies like polydactyly (1.0–3.7%), syndactyly (11–11.8%), butterfly vertebrae (11.1%) and 13 ribs (2–19%). Orthopaedic findings are important manifestations of the 22q11.2DS, both in bringing patients to diagnostic attention and in requiring surveillance and appropriate intervention. Data on these manifestations are scattered and incomprehensive. Routinely screening for cervical anomalies, scoliosis, and upper and lower limb malformations is recommended in this vulnerable group of patients.

Complete Remodeling after Conservative Treatment of a Severely Angulated Odontoid Fracture in a Patient with Osteogenesis Imperfecta : A Case Report

Study Design. Case report. Objective. This is the first case report describing successful healing and remodeling of a traumatic odontoid fracture that was dislocated and severely angulated in a patient with osteogenesis imperfecta who was treated conservatively. Summary of Background Data. Osteogenesis imperfecta (OI) is a rare genetic disorder resulting in a low bone mass and bone fragility, predisposing these patients to fractures that often occur at a young age. Although any bone in the body may be involved, odontoid fractures are uncommon in this population. Because of a very high fusion rate, conservative management is accepted as a safe and efficient treatment of fractures of the odontoid in children. Several authors, however, recommend surgical treatment of patients who have failure of conservative treatment and have severe angulation or displacement of the odontoid. Methods. A 5-year-old female, diagnosed with OI type I, presented with neck pain without any neurological deficits after falling out of a rocking chair backward, with her head landing first on the ground. Computed tomography confirmed a type III odontoid fracture without dislocation and she was initially treated with a rigid cervical orthosis. At 1 and 2 months of follow-up, progressive severe angulation of the odontoid was observed but conservative treatment was maintained as the space available for the spinal cord was sufficient and also considering the patients history of OI. Results. Eight months postinjury, she had no clinical symptoms and there was osseous healing of the fracture with remodeling of the odontoid to normal morphology. Conclusion. Even in patients with OI, severely angulated odontoid fractures might have the capacity for osseous healing and complete remodeling under conservative treatment. Level of Evidence: 5

Prevalence and risk factors for neural axis anomalies in idiopathic scoliosis: a systematic review.

BACKGROUND There is ongoing controversy about the routine use of magnetic resonance imaging (MRI) preoperatively in patients with presumed idiopathic scoliosis (IS). Routine MRI can help identify possible causes for the deformity and detect anomalies that could complicate deformity surgery. However, routine MRI increases health-care costs significantly and may reveal mild variations from normal findings without clinical relevance, which can still lead to anxiety and influence decision-making. PURPOSE Given the necessity to make evidence-based decisions both in the light of quality of care and cost control, the aim of this review is to report the prevalence of neural axis anomalies in IS and to identify risk factors associated with these anomalies. STUDY DESIGN A systematic review was carried out. METHODS An electronic search of PubMed, Embase, Cochrane, and Cinahl until May 2017 was performed. Studies were assessed by two reviewers independently according to predetermined inclusion (MRI in presumed IS) and exclusion criteria (diagnosis other than IS). RESULTS Fifty-one studies were included comprising 8,622 patients. In 981 patients, anomalies were found, resulting in an overall prevalence of 11.4%. The prevalence was 10.5%, 9.0%, and 14.2% when screening was performed of all IS patients, preoperative patients, or patients with presumed risk factors. The prevalence of a syrinx (3.7%), an Arnold-Chiari malformation (3.0%), or a combination of both (2.5%) was highest. Less frequent diagnoses included tethered cord (0.6%), an incidental malignancy (0.3%), and split cord malformations (0.2%). Risk factors for intraspinal anomalies included early-onset scoliosis, male gender, atypical curves, thoracic kyphosis, and abnormal neurologic findings such as reflexes and sensation. CONCLUSIONS This systematic review shows that a significant number of patients have intraspinal anomalies on preoperative MRI in (presumed) IS. The prevalence of finding spinal axis abnormalities increases in preselected patient groups with specific risk factors.

Asymmetry of the Vertebral Body and Pedicles in the True Transverse Plane in Adolescent Idiopathic Scoliosis

Introduction Several studies have reported asymmetry of the vertebral bodies and between the concave and convex pedicles in AIS. There is ongoing debate about its magnitude and whether this caused by a primary growth disturbance, or is secondary to inherent asymmetrical loading within the curvature. The objective of this study is to quantify the asymmetry of the vertebral bodies and pedicles in the true transverse plane in adolescent idiopathic scoliosis (AIS) and to compare this with normal anatomy. Materials and Methods Vertebral body and pedicle asymmetry in the primary thoracic and lumbar curves were evaluated in the true transverse plane of the vertebral bodies on computed tomographic scans of 77 AIS patients with primary curves between 51–105° (thoracic) and 41–88° (lumbar). Magnitude of asymmetry was compared with the corresponding vertebrae in 32 non-scoliotic controls. Vertebral body asymmetry was defined as the percentage of left-right overlap of the vertebral endplates (i.e., 100% indicating perfect symmetry, 0% complete asymmetry). Additionally, the pedicle width and length, length of the ideal pedicle screw trajectory, transverse pedicle angle as well as amount of axial rotation were calculated for each level. Results Vertebrae showed asymmetry both in scoliotics and controls. In thoracic scoliosis, throughout the curve from end vertebra to end vertebra, there was on average significantly more asymmetry than in the controls over the same vertebrae (96.0% in AIS versus 96.4% in controls; p = 0.005). The asymmetry was more pronounced around the apex (95.8%) than at the end vertebrae (96.3%; p = 0.031). The lumbar vertebral bodies in AIS showed a similar pattern, with asymmetry being more pronounced than in controls (95.8% versus 97.2%; p < 0.001), but without significant difference between the apex and the end vertebrae. In the thoracic apex; the concave pedicle was significantly thinner (4.5 versus 5.4mm; p < 0.001) and longer (20.9 versus 17.9mm; p < 0.001) than the convex one, the length of the ideal screw trajectory was longer on the concavity (43.0 versus 37.3mm; p < 0.001) and the transverse pedicle angle was greater (12.3 versus 5.7°; p < 0.001). In the lumbar apex, the concave pedicle was shorter than convex (21.9 versus 24.5 mm; p < 0.001) and its transverse pedicle angle was greater (16.5 versus 9.5°; p = 0.015), there was no significant difference in pedicle width and the length of the ideal screw trajectory between concave and convex in the lumbar apex. The amount of axial rotation within the curve did not correlate with the vertebral asymmetry. Conclusions Even in non-scoliotic controls, there is a slight degree of asymmetry in the true transverse plane of vertebral bodies and pedicles. This vertebral and pedicle asymmetry, however, was slightly more pronounced in moderate to severe scoliosis patients, mostly around the rotated apical zones, with concave pedicles being thinner and longer. No linear relation between the amount of axial rotation and asymmetry could be observed in these severe AIS patients, suggesting that asymmetrical vertebral growth does not initiate rotation, but rather follows it as a secondary phenomenon.

Upright, prone and supine spinal morphology in adolescent idiopathic scoliosis

Introduction Adolescent idiopathic scoliosis patients are exposed to ten times more radiation as compared with healthy adolescents, this leads to increased risk of developing malignancies. To minimize the radiation exposure, non-ionizing imaging modalities, such as MRI, can be used, but this is acquired in supine positioning, unlike the standing X-rays that are the gold standard. As far as we know, this is the first study to compare the 2-D morphology of the spine on conventional radiographs with the 3-D morphology on supine MRI and prone CT images. The objective is to evaluate the correlation between the morphology of the spine on conventional radiographs in the upright position and 3-D supine and prone imaging modalities in patients with adolescent idiopathic scoliosis. Material and Methods 62 adolescent idiopathic scoliosis patients planned for scoliosis surgery and had undergone standard pre-operative work-up (upright radiographs, supine MRI for exclusion of neural axis abnormalities and prone CT for navigation surgery for posterior pedicle screw fixation) were included. In all three positions, Cobb angles, thoracic kyphosis, lumbar lordosis and apical vertebral rotation (2-D X-rays: method of Perdriolle, 3-D scans: semi-automatic software) were determined. In addition, on reconstructed 3-D MR and CT images, the true sagittal and coronal morphology were measured semi-automatically (previously validated technique). Chi-square tests were used for correlation analysis between the positions. Results In the thoracic and (thoraco)lumbar curves, Cobb angles correlated significantly between conventional radiographs (68 ± 15° and 44 ± 17°), supine MRI (57 ± 14° and 35 ± 16°) and prone CT (54 ± 15° and 33 ± 15°; r ≥ 0.89; p < 0.001). In the axial plane, the apical vertebral rotation showed a good correlation between the positions (upright, 22 ± 12°; prone, 20 ± 9° and supine, 16 ± 11°; r ≥ 0.56; p < 0.001). The thoracic kyphosis and lumbar lordosis on the conventional upright X-rays did not correlate with the true sagittal morphology on MRI or CT. The relation of the thoracic Cobb angle between the standing X-rays and the lying down images of moderate to severe patients is expressed by the formula: upright radiograph (°) = 10.81 + 1.01*supine MRI(°) and prone CT(°) = −3.02 + 1.00*supine MRI(°). Conclusion Although there is slight underestimation of the morphology of the 3-D spinal curvature in the supine position as compared with upright, there is a significant correlation of the deformation in all three dimensions between the different body positions and imaging modalities. Therefore, accurate estimation of the upright morphology of adolescent idiopathic scoliosis is possible, using non-ionizing supine MRI or prone CT scans.