Current biomechanical theories on the etiopathogenesis of idiopathic scoliosis.

PURPOSE: There is great controversy about the etiologic origin of adolescent idiopathic scoliosis. Multiple theories have been suggested, including metabolic aspects, endocrine dysfunction, neurological central abnormalities, genetic predisposition and epigenetic factors involved in the development of scoliosis. However, there has always been speculations based on human biomechanical behavior. METHODS: In this article, we performed a literature review on the biomechanical traits of human posture, and the proposed theories that explain the special characteristics present in idiopathic scoliosis. RESULTS: The current theory on the etiopathogeneis of AIS suggests that dorsally directed shear loads acting on a preexisting axial plane rotation, in a posteriorly inclined sagittal plane of a growing patient, together with disc maturation, collagen quality at this phase of development and immaturity of proprioception, is the perfect scenario to spark rotational instability and create the three-dimensional deformity that defines idiopathic scoliosis. CONCLUSION: The unique spinal alignment of human bipedalism, gravity and muscle forces acting straight above the pelvis to preserve an upright balance, and the instability of the soft tissue in a period of growth development, is an appealing cocktail to try to explain the genesis of this condition in humans.

MRI-based measurements of spondylolisthesis and kyphosis in degenerative cervical myelopathy.

BACKGROUND: To provide normative data and to determine accuracy and reliability of preoperative measurements of spondylolisthesis and kyphosis on supine static magnetic resonance imaging (MRI) of patients with degenerative cervical myelopathy. METHODS: T2-weighted midsagittal images of the cervical spine were in 100 cases reviewed twice by one junior observer, with an interval of 3 months, and once by a senior observer. The spondylolisthesis slip (SSlip, mm) and the modified K-line interval (mK-line INT, mm) were assessed for accuracy with the standard error of measurement (SEm) and the minimum detectable change (MDC). Intraobserver and interobserver reliability levels were determined using the intraclass correlation coefficient (ICC). RESULTS: The SEm was 0.5 mm (95% CI 0.4-0.6) for spondylolisthesis and 0.6 mm (95% CI 0.5-0.7) for kyphosis. The MDC, i.e., the smallest difference between two examinations that can be detected with statistical certainty, was 1.5 mm (95% CI 1.2-1.8) for spondylolisthesis and 1.6 mm (95% CI 1.3-1.8) for kyphosis. The highest reliability levels were seen between the second observation of the junior examiner and the senior observer (ICC = 0.80 [95% CI 0.70-0.87] and ICC = 0.96 [95% CI 0.94-0.98] for SSlip and mK-line INT, respectively). CONCLUSIONS: This study provides normative values of alignment measurements of spondylolisthesis and kyphosis in DCM patients. It further shows the importance of taking measurement errors into account when defining cut-off values for cervical deformity parameters and their potential clinical application in surgical decision-making.

Quantifying Typical Progression of Adolescent Idiopathic Scoliosis: Longitudinal Three-Dimensional MRI Measures of Disk and Vertebral Deformities.

STUDY DESIGN: A prospective cohort study. OBJECTIVE: Detail typical three-dimensional segmental deformities and their rates of change that occur within developing adolescent idiopathic scoliosis (AIS) spines over multiple timepoints. SUMMARY OF BACKGROUND DATA: AIS is a potentially progressive deforming condition that occurs in three dimensions of the scoliotic spine during periods of growth. However, there remains a gap for multiple timepoint segmental deformity analysis in AIS cohorts during development. MATERIALS AND METHODS: Thirty-six female patients with Lenke 1 AIS curves underwent two to six sequential magnetic resonance images. Scans were reformatted to produce images in orthogonal dimensions. Wedging angles and rotatory values were measured for segmental elements within the major curve. Two-tailed, paired t tests compared morphologic differences between sequential scans. Rates of change were calculated for variables given the actual time between successive scans. Pearson correlation coefficients were determined for multidimensional deformity measurements. RESULTS: Vertebral bodies were typically coronally convexly wedged, locally lordotic, convexly axially rotated, and demonstrated evidence of local mechanical torsion. Between the first and final scans, apical measures of coronal wedging and axial rotation were all greater in both vertebral and intervertebral disk morphology than nonapical regions (all reaching differences where P <0.05). No measures of sagittal deformity demonstrated a statistically significant change between scans. Cross-planar correlations were predominantly apparent between coronal and axial planes, with sagittal plane parameters rarely correlating across dimensions. Rates of segmental deformity changes between earlier scans were characterized by coronal plane convex wedging and convexly directed axial rotation. The major locally lordotic deformity changes that did occur in the sagittal plane were static between scans. CONCLUSIONS: This novel investigation documented a three-dimensional characterization of segmental elements of the growing AIS spine and reported these changes across multiple timepoints. Segmental elements are typically deformed from initial presentation, and subsequent changes occur in separate orthogonal planes at unique times.

Calcium sensing and signaling are impaired in the lumbar spine of a rat model of congenital kyphosis.

PURPOSE: Kyphosis involves spines curving excessively backward beyond their physiological curvature. Although the normal structure of the spinal vertebrae is extremely important for maintaining posture and the normal function of the thoracic and abdominal organs, our knowledge concerning the pathogenesis of the disease is insufficient. We herein report that the downregulation of the calcium signaling pathway is involved in the pathogenesis of congenital kyphosis. METHODS: The third to fifth lumbar spine segments, the kyphotic region of Ishibashi (IS) rats, which are used as a model of congenital kyphoscoliosis, were collected. A DNA microarray, quantitative PCR, Western blotting, and immunohistochemistry were used to measure the expression of genes and proteins related to intracellular calcium signaling. RESULTS: We found that the expression of calcium-sensing receptor (CaSR) and transient receptor potential vanilloid 1 (Trpv1)-two receptors involved in the calcium signaling-was decreased in the lumbar spine of IS rats. We also observed that the number of CaSR-immunoreactive and Trpv1-immunoreactive cells in the lumbar spine of IS rats was lower than in wild-type rats. Furthermore, the expression of intracellular molecules downstream of these receptors, such as phosphorylated protein kinase C, c-Jun N-terminal kinase, and neural EGFL-like 1, was also reduced. In fact, the calcium content in the lumbar spine of IS rats was significantly lower than that in wild-type rats. CONCLUSION: These results indicate that adequate calcium signaling is extremely important for the regulation of normal bone formation and may also be a key factor for understanding the pathogenesis of congenital kyphosis.

Quantifying Muscle Size Asymmetry in Adolescent Idiopathic Scoliosis Using Three-dimensional Magnetic Resonance Imaging.

STUDY DESIGN: This is a case-control study of prospectively collected data. OBJECTIVE: To quantify paraspinal muscle size asymmetry in adolescent idiopathic scoliosis (AIS) and determine if this asymmetry is (i) greater than observed in adolescent controls with symmetrical spines; and (ii) positively associated with skeletal maturity using Risser grade, scoliosis severity using the Cobb angle, and chronological age in years. SUMMARY OF BACKGROUND DATA: AIS is a three-dimensional deformity of the spine which occurs in 2.5% to 3.7% of the Australian population. There is some evidence of asymmetry in paraspinal muscle activation and morphology in AIS. Asymmetric paraspinal muscle forces may facilitate asymmetric vertebral growth during adolescence. METHODS: An asymmetry index [Ln(concave/convex volume)] of deep and superficial paraspinal muscle volumes, at the level of the major curve apex (Thoracic 8-9 th vertebral level) and lower-end vertebrae ( LEV , Thoracic 10-12 th vertebral level), was determined from three-dimensional Magnetic Resonance Imaging of 25 adolescents with AIS (all right thoracic curves), and 22 healthy controls (convex=left); all female, 10 to 16 years. RESULTS: Asymmetry index of deep paraspinal muscle volumes was greater in AIS (0.16±0.20) than healthy spine controls (-0.06±0.13) at the level of the apex ( P <0.01, linear mixed-effects analysis) but not LEV ( P >0.05). Asymmetry index was positively correlated with Risser grade ( r =0.50, P <0.05) and scoliosis Cobb angle ( r =0.45, P <0.05), but not age ( r =0.34, P >0.05). There was no difference in the asymmetry index of superficial paraspinal muscle volumes between AIS and controls ( P >0.05). CONCLUSIONS: The asymmetry of deep apical paraspinal muscle volume in AIS at the scoliosis apex is greater than that observed at equivalent vertebral levels in controls and may play a role in the pathogenesis of AIS.

MRI features of spinal chronic recurrent multifocal osteomyelitis/chronic non-bacterial osteomyelitis in children.

BACKGROUND: Spinal lesions in pediatric chronic recurrent multifocal osteomyelitis/chronic non-bacterial osteomyelitis (CRMO/CNO) can cause permanent sequelae; thus, early recognition of these is vital for management. OBJECTIVE: To characterize the MR imaging features and patterns of pediatric spinal CRMO/CNO. MATERIALS AND METHODS: This cross-section study received IRB approval. The first available MRI with documented spine involvement in children with CRMO/CNO was reviewed by a pediatric radiologist. Descriptive statistics were used to describe the characteristics of vertebral lesions, disc involvement, and soft tissue abnormality. RESULTS: Forty-two patients were included (F:M, 30:12); median age was 10 years (range 4-17). At diagnosis, 34/42 (81%) had spine involvement. Kyphosis in 9/42 (21%) and scoliosis in 4/42 (9.5%) patients were present at the time of spinal disease recognition. Vertebral involvement was multifocal in 25/42 (59.5%). Disc involvement was found in 11/42 (26%) patients, commonly in the thoracic spine and often with adjacent vertebrae height loss. Posterior element abnormalities were present in 18/42 patients (43%) and soft tissue involvement in 7/42 (17%). One hundred nineteen vertebrae were affected, commonly the thoracic vertebrae (69/119; 58%). Vertebral body edema was focal in 77/119 (65%) and frequently superior (42/77; 54%). Sclerosis and endplate abnormality were present in 15/119 (13%) and 31/119 (26%) vertebrae, respectively. Height loss was present in 41/119 (34%). CONCLUSION: Chronic non-bacterial osteomyelitis of spine is usually thoracic. Vertebral body edema is often focal at the superior vertebral body. Kyphosis and scoliosis occur in a quarter and vertebral height loss in a third of children at spinal disease recognition.

Glycerol induced paraspinal muscle degeneration leads to hyper-kyphotic spinal deformity in wild-type mice.

Degenerative spinal disorders, including kyphotic deformity, are associated with a range of degenerative characteristics of the paraspinal musculature. It has therefore been hypothesized that paraspinal muscular dysfunction is a causative factor for degenerative spinal deformity; however, experimental studies demonstrating causative relationships are lacking. Male and female mice received either glycerol or saline injections bilaterally along the length of the paraspinal muscles at four timepoints, each separated by 2 weeks. Immediately after sacrifice, micro-CT was performed to measure spinal deformity; paraspinal muscle biopsies were taken to measure active, passive and structural properties; and lumbar spines were fixed for analysis of intervertebral disc (IVD) degeneration. Glycerol-injected mice demonstrated clear signs of paraspinal muscle degeneration and dysfunction: significantly (p < 0.01) greater collagen content, lower density, lower absolute active force, greater passive stiffness compared to saline-injected mice. Further, glycerol-injected mice exhibited spinal deformity: significantly (p < 0.01) greater kyphotic angle than saline-injected mice. Glycerol-injected mice also demonstrated a significantly (p < 0.01) greater IVD degenerative score (although mild) at the upper-most lumbar level compared to saline-injected mice. These findings provide direct evidence that combined morphological (fibrosis) and functional (actively weaker and passively stiffer) alterations to the paraspinal muscles can lead to negative changes and deformity within the thoracolumbar spine.

[Pathologic features of paraspinal muscle biopsies in patients with adolescent idiopathic scoliosis].

OBJECTIVE: To characterize the paraspinal muscles of adolescent idiopathic scoliosis (AIS) patients, and to further explore its etiology. METHODS: Clinical records and paraspinal muscle biopsies at the apex vertebra region during posterior scoliosis correction surgery of 18 AIS were collected from November 2018 to August 2019. Following standardized processing of fresh muscle tissue biopsy, serial sections with conventional hematoxylin-eosin (HE) and histochemical and immunohistochemical (IHC) with antibody Dystrophin-1 (R-domain), Dystrophin-2 (C-terminal), Dystrophin-3 (N-terminal), Dystrophin-total, Myosin (fast), major histocompatibility complex 1 (MHC-1), CD4, CD8, CD20, and CD68 staining were obtained. Biopsy samples were grouped according to the subjects' median Cobb angle (Cobb angle ≥ 55° as severe AIS group and Cobb angle < 55° as mild AIS group) and Nash-Moe's classification respectively, and the corresponding pathological changes were compared between the groups statistically. RESULTS: Among the 18 AIS patients, 8 were in the severe AIS group (Cobb angle ≥55°) and 10 in the mild AIS group (Cobb angle < 55°). Both severe and mild AIS groups presented various of atrophy and degeneration of paraspinal muscles, varying degrees and staining patterns of immune-expression of Dystrophin-3 loss, especially Dystrophin-2 loss in severe AIS group with significant differences, as well as among the Nash-Moe classification subgroups. Besides, infiltration of CD4+ and CD8+ cells in the paraspinal muscles and tendons was observed in all the patients while CD20+ cells were null. The expression of MHC-1 on myolemma was present in some muscle fibers. CONCLUSION: The histologic of paraspinal muscle biopsy in AIS had similar characteristic changes, the expression of Dystrophin protein was significantly reduced and correlated with the severity of scoliosis, suggesting that Dystrophin protein dysfunctions might contribute to the development of scoliosis. Meanwhile, the inflammatory changes of AIS were mainly manifested by T cell infiltration, and there seemed to be a certain correlation between inflammatory cell infiltration, MHC-1 expression and abnormal expression of Dystrophin. Further research along the lines of this result may open up new ideas for the diagnosis of scoliosis and the treatment of paraspinal myopathy.

Dropped head syndrome: a treatment strategy and surgical intervention.

PURPOSE: The pathology of dropped head syndrome (DHS) is diverse, and reports of surgery for DHS are scarce. We aimed to describe surgery for DHS and to investigate the surgical outcomes thereof. METHODS: We enrolled 40 consecutive patients (six males and 34 females; average age at surgery, 72.0 years) with DHS who underwent correction surgeries at a single institute. Short fusion (SF), with the extent of fixation mainly at the cervical region, was performed for 27 patients; long fusion (LF), involving the cervical and thoracic spine, for 13. Clinical and radiological outcomes were investigated, and factors analyzed using the Japanese Orthopedic Association Cervical Myelopathy Evaluation Questionnaire (JOACMEQ). RESULTS: All patients were able to gaze horizontally at the follow-up. Instances of five transient C5 palsy results, and five distal junctional kyphosis results were found, but no revisions were reported due to recurrence. Patients whose T1 slope-20° was smaller than the C2-7 angle postoperatively exhibited better clinical outcomes in the three domains of the JOACMEQ, regardless of the extent of fixation. CONCLUSION: For cases where the T1 slope is relatively small, and approximately 10° of cervical lordosis is predicted to be obtained postoperatively, SF is appropriate. Alternatively, for cases with higher T1 slope, obtaining a cervical lordosis over 20° has a risk of postoperative complications. For such cases, it is an option to perform an LF involving the cervical and thoracic spine.

Loss of cervical sagittal alignment worsens the cervical spinal lesions in patients with Hirayama disease.

OBJECTIVE: To quantify the cervical sagittal alignment in patients with Hirayama disease (HD) and to investigate the effect of loss of cervical sagittal alignment upon the cervical spinal lesions in HD. METHODS: Cervical sagittal alignments were measured in 253 HD patients and 63 healthy subjects by C2-C7 Cobb and a modified method of Toyama et al. Motor unit number estimation (MUNE) was performed in bilateral abductor pollicis brevis (APB) in all HD patients, and 31 patients further underwent cervical diffusion tensor imaging (DTI). RESULTS: Compared with healthy subjects, HD patients showed lower C2-C7 Cobb (P < 0.05), and 83.4% patients showed loss of cervical lordosis (cervical straight or kyphosis), which was greater than healthy subjects (55.6%, P < 0.05). Compared with lordotic/straight group, patients with cervical kyphosis showed lower MUNE values and greater single motor unit potential (SMUP) in bilateral APB, and higher apparent dispersion coefficient (ADC) and lower fractional anisotropy were observed at C4/C5 level in the latter than the former (P < 0.05). C2-C7 Cobb was associated with both C4/C5 ADC and bilateral SMUP (P < 0.05). CONCLUSIONS: Most HD patients showed loss of cervical sagittal alignments, and both MUNE and DTI detections demonstrated a positive correlation between loss of cervical sagittal alignments and cervical spinal lesions in HD. These findings supported that loss of cervical sagittal alignments may worsen motor impairments in HD. Therefore, it is necessary for clinicians to be aware of restoring cervical sagittal alignments during HD treatment.

Preoperative Association Between Quantitative Lumbar Muscle Parameters and Spinal Sagittal Alignment in Lumbar Fusion Patients.

STUDY DESIGN: A retrospective cross-sectional study. OBJECTIVE: To assess the association between spinal muscle morphology and spinopelvic parameters in lumbar fusion patients, with a special emphasis on lumbar lordosis (LL). SUMMARY OF BACKGROUND DATA: Maintenance of sagittal alignment relies on muscle forces, but the basic association between spinal muscles and spinopelvic parameters is poorly understood. MATERIALS AND METHODS: Patients operated between 2014 and 2017 who had both lumbar magnetic resonance imaging scan and standing whole-spine radiographs within six months before surgery were included. Muscle measurements were conducted on axial T2-weighted magnetic resonance images at the superior endplate L3-L5 for the psoas and L3-S1 for combined multifidus and erector spinae (paraspinal) muscles. A pixel intensity threshold method was used to calculate the total cross-sectional area (TCSA) and the functional cross-sectional area (FCSA). Spinopelvic parameters were measured on lateral standing whole-spine radiographs and included LL, pelvic incidence (PI), PI-LL mismatch, pelvic tilt, sacral slope, thoracic kyphosis, and sagittal vertical axis. Analyses were stratified by biological sex. Multivariable linear regression analyses with adjustments for age and body mass index (BMI) were performed. RESULTS: A total of 104 patients (62.5% female) were included in the analysis. The patient population was 90.4% White with a median age at surgery of 69 years and a median BMI of 27.8 kg/m 2 . All muscle measurements were significantly smaller in women. PI, pelvic tilt, and thoracic kyphosis were significantly greater in women. PI-LL mismatch was 6.1° (10.6°) in men and 10.2° (13.5°) in women ( P =0.106), and sagittal vertical axis was 45.3 (40.8) mm in men and 35.7 (40.8) mm in women ( P =0.251). After adjusting for age and BMI, paraspinal TCSA at L3-L5, and paraspinal FCSA at L4 showed significant positive associations with LL in women. In men, psoas TCSA at L5 and psoas FCSA at L5 showed significant negative associations with LL, but none of the paraspinal muscle measurements. CONCLUSION: Our findings indicate that psoas and lumbar spine extensor muscles interact differently on LL among men and women, creating a unique mechanical environment. LEVEL OF EVIDENCE: Level 4.

Comparison of Spinopelvic Configuration and Roussouly Alignment Types Between Pediatric and Adult Populations.

STUDY DESIGN: Retrospective cross-sectional study. OBJECTIVE: The aim was to describe spinopelvic alignment types by pelvic incidence (PI) and age to compare the Roussouly classification between pediatric and adult populations. SUMMARY OF BACKGROUND DATA: The Roussouly classification was validated for adults. Alignment types may vary during growth. MATERIALS AND METHODS: Radiographs of 1706 non pathologic individuals (5-49 yr) were analyzed. Individuals ≤19 years were stratified by chronological age and skeletal maturity (triradiate cartilage, Risser), and compared with adults. Global and spinopelvic alignment parameters were assessed. Roussouly Types 1, 2, 3, 3A (anteverted pelvis), and 4 were determined. The distribution of parameters was analyzed by Bayesian inference. The relationship between PI and age by Roussouly type was modeled by linear regression. RESULTS: The Sagittal Vertical Axis C7 decreased during growth and was significantly smaller in adults (20-34 yr) (Pr>0.99). Thoracic kyphosis and lumbar lordosis increased during growth and were larger in adults (Pr<0.025). Lordosis increased mainly in the cranial arch (Pr<0.025). PI and pelvic tilt increased during growth and were larger in adults (Pr<0.025). In children and adolescents, PI<45° represented the largest proportion, significantly larger compared with adults (Pr>0.99). Proportions of Roussouly Types 1 and 2 were similar throughout ages. Types 3 and 4 were rarer during the prepubertal period (Pr<0.025). The proportion of Type 3A was significantly higher in children and adolescents (Pr>0.99). Linear regression showed that Type 4 had the largest PI increase with age, with significantly higher curve slope compared with other types (Pr>0.9999). Types 3, 3A and 2 had similar slopes and lowest PI increase with age. CONCLUSION: Global and spinopelvic alignment changed during childhood and adolescence, leading to different kyphosis and lordosis distribution compared with adults. Growth-related PI increase influenced Roussouly types with typical predominance of Type 3A in the pediatric population and larger PI increase in Type 4. LEVEL OF EVIDENCE: Level III.

Morphological changes of Intervertebral Disc detectable by T2-weighted MRI and its correlation with curve severity in Adolescent Idiopathic Scoliosis.

BACKGROUND: Our previous studies found disproportionate anteroposterior vertebral size is associated with severity of the scoliotic curves in adolescent idiopathic scoliosis (AIS) patients. Subsequent studies showed wedging of vertebral bodies (VB) had less contribution than intervertebral discs (IVD) to the anterior-posterior vertebral column length discrepancy in severe-AIS. However, the exact morphological changes of IVD were not clearly defined. This study aimed to evaluate the morphological and pathological changes of IVD and VB in AIS girls and healthy female controls. METHODS: This study included 33 age-matched female controls and 76 AIS girls with a right-sided thoracic curvature. Wedge angle, height ratio and distance ratio of VB and IVD were measured on the best midline coronal and sagittal planes from reformatted MRI spine. Volumes of VB, IVD and nucleus pulposus (NP) were also evaluated on volumetric images. One-way ANOVA with Bonferroni correction and Pearson correlation tests were used. RESULTS: There was significant difference in wedge angle and height ratio of VB and IVD between AIS and controls. In severe-AIS, the position of NP was significantly shifted to the convexity when compared with non-severe AIS and controls. Whereas, the volume of IVD and NP in severe-AIS was found to be significantly smaller. In addition, Cobb angle was significantly correlated with wedge angle and height ratio, and inversely correlated with the volume of NP. CONCLUSIONS: In addition to wedging of VB and IVD, there was significantly reduced volume of IVD and NP in AIS patients with severe curve, insinuating the mechanical effect of scoliosis leads to a compression on both IVD and NP before significant disc desiccation occurs. We postulate that the compression of IVD and NP can contribute to curve progression in severe-AIS, these patients are more prone to disc degeneration in adulthood if no operative treatment is offered. Further longitudinal study on these parameters is still warranted.

Spinal malformation - A biochemical analysis using congenital kyphosis rats.

Spinal kyphosis involves the vertebrae curving excessively backward, beyond their physiological curvature. Although the normal structure of the spinal vertebrae is extremely important for maintaining posture, the normal function of the thoracic and abdominal organs, and cosmetics, our knowledge concerning the pathogenesis of this disease is lacking. Furthermore, the responsible gene has not yet been identified. In this short review, we summarize the current state of kyphosis research and introduce the molecular and cellular mechanisms associated with the pathogenesis of this disease, based on findings obtained using rats that develop kyphosis.

Cardiorespiratory function of patients undergoing surgical correction of Scheuermann's hyperkyphosis.

The aim of this study was to analyze the impact of surgical correction of the thoracic deformity on the cardiorespiratory function of patients with moderate-severe Scheuermann's hyperkyphosis (SK). A series of 23 adolescents with SK who underwent surgery through an only posterior approach using all pedicle screw constructs were included in the study. Cardiorespiratory parameters were measured during a maximal exercise tolerance test before and 2 years after surgery. Heart rate, oxygen saturation (SatO2), maximum oxygen uptake (VO2 max), ventilatory capacity at maximal exercise (VEmax), and energy costs were recorded. There were statistically significant differences in the forced vital capacity (FVC) (P < 0.05), total VO2max (ml/min) (P < 0.01), maximum expired volume (VEmax) per minute (P < 0.01) and cardiovascular efficiency (HR/VO2 ratio) (P < 0.05). None of these changes were clinically relevant. There were no changes in the VO2max per kg of body mass. The magnitude of the kyphosis correction did not correlate with the change in normalized VO2max or VEmax. In conclusion, patients with moderate-severe SK improve their baseline respiratory limitations and the tolerance to maximum exercise 2 years after surgery. However, the slight cardiorespiratory functional improvements should not necessarily be attributed to the surgery, and could also be caused solely by the residual growth of the lungs and thorax. Furthermore, respiratory functional changes are under thresholds considered as clinically relevant.

Age-related degenerative changes and sex-specific differences in osseous anatomy and intervertebral disc height of the thoracolumbar spine.

The aim of this study was to determine age-related changes and sex-specific differences in sagittal alignment, range of motion (ROM), and intervertebral disc height of the thoracolumbar spine in healthy subjects. Lateral neutral and flexion-extension radiographs of the thoracolumbar spine of 627 asymptomatic subjects (307 males and 320 females; average age, 49.6 ±â€¯16.5 years) were evaluated. We included at least 50 males and 50 females in each decade of life between the 20s and the 70s. Intervertebral disc height from T10/T11 to L5/S1, local lordotic alignment, and ROM from T10-T11 to L5-S1 were measured. T10-L2 kyphosis and T12-S1 lordosis as well as flexion, extension, and total ROM were measured. T10-L2 kyphosis did not markedly change with age in subjects of either sex but a sudden increase was noted in the 70s females. T12-S1 lordosis increased with age in both sexes, except the 70s. Flexion, extension, and total ROM at T10-L2 and T12-S1 decreased with age in most subjects. The levels from L3-L4 to L5-S1 were conspicuous as mobile segments. Intervertebral disc height gradually increased from T10/T11 to L4/L5; the shortest was at T10/T11 and the longest at L3/L4 or L4/L5 in all subjects. Age-related decreases in intervertebral disc height were most prominent at L4/L5 in middle-aged and elderly individuals of both sexes. Normative values of sagittal alignment, ROM, and intervertebral disc height at each segmental level were established in both sexes and all age groups in healthy subjects.

Transiency of postoperative cervical kyphosis seen after surgical correction of sagittal malalignment in adult spinal deformity patients.

OBJECTIVE: In this study, we evaluated factors affecting changes in cervical lordosis after deformity correction and during follow-up period in adult spinal deformity (ASD) patients with severe sagittal imbalance. METHODS: Seventy-nine patients, with an average age of 71.6 years, who underwent long-segment fixation from T10 to S1 with sacropelvic fixation were included. We performed a comparative analysis of the radiographic parameters after surgery (Post) and at the last follow-up (Last). We calculated the Pearson's correlation coefficient and performed multilinear regression analysis to predict independent parameters for Post and Last cervical lordosis (CL), T1 slope (T1S), and thoracic kyphosis (TK). RESULTS: Hyperlordotic changes of -23.3° in CL before surgery was reduced to -7° after surgery, and Last CL had increased to -15.3°. T1S was reduced from 27° before surgery to 14.4° after surgery and had increased to 18.8° at the last follow-up. Through multilinear regression analysis, we found that Post CL and T1S were more significantly affected by the amount of LL correction (p = .045 and .049). The effect of Last T1S was significantly associated with the Last CL; the effect of Last TK, with the Last T1S; and the effect of Post PI-LL, with the Last TK (p < .05). CONCLUSION: The postoperative kyphotic change in CL in ASD patients with preoperative cervical hyperlordosis is not permanent and is affected by drastic LL correction and SVA restoration. To achieve spinopelvic harmony proportional to the difference in LL relative to PI, TK becomes modified over time to increase T1S and CL, in an effort to achieve optimal spine curvature.

Sagittal body alignment in a sitting position in children is not affected by the generalized joint hypermobility.

Back pain may be related to an improper sitting position. The aim of the study was to assess the sagittal curvatures of the spine in a sitting position in children with generalized joint hypermobility (GJH). The study included 302 children aged 8-14 years. The sagittal curvatures of the spine (sacral slope, lumbar lordosis, thoracic kyphosis with its lower and upper part) were assessed using the Saunders digital inclinometer. In order to assess GJH a 9-point Beighton scale was used. The study revealed no significant differences (p > 0.05) in sagittal curvatures of the spine in a relaxed sitting position between children with and without GJH. Regardless of the occurrence of GJH, kyphotic alignment of the spine was noted in a relaxed sitting. GJH does not affect the position of the trunk in a sagittal plane in a relaxed sitting position in children aged 8-14 years. A relaxed sitting position in children with and without GJH is characterized by a kyphotic position of the spine caused by an improper position of pelvis and lumbar segment of the spine.

Association Between Vertebral Rotatory Subluxation and the Apical Vertebra in Degenerative Lumbar Scoliosis.

OBJECTIVE: To identify the apical vertebra is relate to the occurrence of vertebral rotatory subluxation (VRS) in degenerative lumbar scoliosis. METHODS: In total, 86 patients with degenerative lumbar scoliosis included in this retrospective study were divided into 2 groups: with VRS and without VRS. Coronal and sagittal parameters were measured on whole-spine anteroposterior and lateral radiographs. The impact of VRS on the spine and pelvis parameters was statistically analyzed, and the correlation between the occurrence of VRS and the apical vertebra was analyzed by using logistic regression. RESULTS: VRS was present in 49 patients with degenerative lumbar scoliosis and absent in 37 patients. Compared with the patients without VRS, the patients with VRS had a smaller lumbar lordosis and thoracic kyphosis (P < 0.05) and a larger apical vertebra translation, apical vertebra tilt angle, Cobb angle, and pelvic incidence-lumbar lordosis (P < 0.05). Logistic regression analysis showed that apical vertebra translation and apical vertebra tilt angle were risk factors for the occurrence of VRS. The receiver operating characteristic curve analysis showed that apical vertebra translation greater than 23.2 mm and apical vertebra tilt angle greater than 11.8° were related to a greater probability of VRS in patients with degenerative lumbar scoliosis. CONCLUSIONS: VRS is an important characteristic to consider in degenerative lumbar scoliosis that can affect the coronal and sagittal alignment. The apical vertebra is correlated with the occurrence of VRS; an apical vertebra translation greater than 23.2 mm and apical vertebra tilt angle greater than 11.8° are highly correlate with the occurrence of VRS.