Etiology and pathogenesis of adolescent idiopathic scoliosis

Despite many years of dedicated research into the etio-pathogenesis, not one single cause for adolescent idiopathic scoliosis has been identified. The purpose of this review is to give a comprehensive overview of the current evidence and main etiological theories. Intrinsic causal mechanisms are found in the alignment of the upright human spino-pelvic complex and growth patterns of the immature spine. Studies on potential extrinsic mechanisms are mainly focused on neuromuscular, metabolic, and genetic etiological pathways. We can conclude that scoliosis is the spine's preconditioned response to a multitude of offenses that lead to a disturbance of the delicate human rotational spino-pelvic balance during growth

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 patient's 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

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

STUDY DESIGN: Cross-sectional. OBJECTIVE: To investigate the presence and magnitude of anterior spinal overgrowth in neuromuscular scoliosis and compare this to 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 non-idiopathic scoliosis has not been reported. METHODS: Supine CT scans of thirty AIS patients (thoracic Cobb 21-81°), thirty neuromuscular (NM) scoliotic patients (thoracic Cobb 19-101°) and thirty non-scoliotic controls were used. The difference in length in per cents between the anterior and posterior side (((ΔA-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% versus A-P% body -2.5 ± 2.6%; P < 0.001, NM: A-P% disc +19.1 ± 18.0% versus 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). CONCLUSIONS: 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

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

STUDY DESIGN: Cross-sectional. OBJECTIVE: To investigate the presence and magnitude of anterior spinal overgrowth in neuromuscular scoliosis and compare this to 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 non-idiopathic scoliosis has not been reported. METHODS: Supine CT scans of thirty AIS patients (thoracic Cobb 21-81°), thirty neuromuscular (NM) scoliotic patients (thoracic Cobb 19-101°) and thirty non-scoliotic controls were used. The difference in length in per cents between the anterior and posterior side (((ΔA-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% versus A-P% body -2.5 ± 2.6%; P < 0.001, NM: A-P% disc +19.1 ± 18.0% versus 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). CONCLUSIONS: 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

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

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%;

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

BACKGROUND: Patients with adolescent idiopathic scoliosis (AIS) are usually investigated by serial imaging studies during the course of treatment, some imaging involves ionizing radiation, and the radiation doses are cumulative. Few studies have addressed the correlation of spinal deformity captured by these different imaging modalities, for which patient positioning are different. To the best of our knowledge, this is the first study to compare the coronal, axial, and sagittal morphology of the scoliotic spine in three different body positions (upright, prone, and supine) and between three different imaging modalities (X-ray, CT, and MRI). METHODS: Sixty-two AIS patients scheduled for scoliosis surgery, and having undergone standard pre-operative work-up, were included. This work-up included upright full-spine radiographs, supine bending radiographs, supine MRI, and prone CT as is the routine in one of our institutions. In all three positions, Cobb angles, thoracic kyphosis (TK), lumbar lordosis (LL), and vertebral rotation were determined. The relationship among three positions (upright X-ray, prone CT, and supine MRI) was investigated according to the Bland-Altman test, whereas the correlation was described by the intraclass correlation coefficient (ICC). RESULTS: Thoracic and lumbar Cobb angles correlated significantly between conventional radiographs (68° ± 15° and 44° ± 17°), prone CT (54° ± 15° and 33° ± 15°), and supine MRI (57° ± 14° and 35° ± 16°; ICC ≥0.96; P < 0.001). The thoracic and lumbar apical vertebral rotation showed a good correlation among three positions (upright, 22° ± 12° and 11° ± 13°; prone, 20° ± 9° and 8° ± 11°; supine, 16° ± 11° and 6° ± 14°; ICC ≥0.82; P < 0.001). The TK and LL correlated well among three different positions (TK 26° ± 11°, 22° ± 12°, and 17° ± 10°; P ≤ 0.004; LL 49° ± 12°, 45° ± 11°, and 44° ± 12°; P < 0.006; ICC 0.87 and 0.85). CONCLUSIONS: Although there is a generalized underestimation of morphological parameters of the scoliotic deformity in the supine and prone positions as compared to the upright position, a significant correlation of these parameters is still evident among different body positions by different imaging modalities. Findings of this study suggest that severity of scoliotic deformity in AIS patients can be largely represented by different imaging modalities despite the difference in body positioning

13Th International Conference On Conservative Management Of Spinal Deformities And First Joint Meeting Of The International Research Society On Spinal Deformities And The Society On Scoliosis Orthopaedic And Rehabilitation Treatment – Sosort-Irssd 2016 Meeting

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