Progression Of Scoliotic Curve Research Articles

Unraveling the Link of Altered TGFβ Signaling with Scoliotic Vertebral Malformations in Osteogenesis Imperfecta: A Comprehensive Review.

Osteogenesis Imperfecta (OI) is a genetic disorder caused by mutations in genes responsible for collagen synthesis or polypeptides involved in the formation of collagen fibers. Its predominant skeletal complication is scoliosis, impacting 25 to 80% of OI patients. Vertebral deformities of the scoliotic curves in OI include a variety of malformations such as codfish, wedged-shaped vertebrae or platyspondyly, craniocervical junction abnormalities, and lumbosacral spondylolysis and spondylolisthesis. Although the precise pathophysiology of these spinal deformities remains unclear, anomalies in bone metabolism have been implicated in the progression of scoliotic curves. Bone Mineral Density (BMD) measurements have demonstrated a significant reduction in the Z-score, indicating osteoporosis and a correlation with the advancement of scoliosis. Factors such as increased mechanical strains, joint hypermobility, lower leg length discrepancy, pelvic obliquity, spinal ligament hypermobility, or vertebrae microfractures may also contribute to the severity of scoliosis. Histological vertebral analysis has confirmed that changes in trabecular microarchitecture, associated with inadequate bone turnover, indicate generalized bone metabolic defects in OI. At the molecular level, the upregulation of Transforming Growth factor-β (TGFβ) signaling in OI can lead to disturbed bone turnover and changes in muscle mass and strength. Understanding the relationship between spinal clinical features and molecular pathways could unveil TGFβ -related molecular targets, paving the way for novel therapeutic approaches in OI.

A comparison between long term outcomes of surgical and orthotic management of scoliosis in adolescents

Orthotic and surgical management are the main approaches used to control scoliot-ic curve progression. Treatment options are selected based on the age of the patient and severity of scoliotic curve. Although previous studies have investigated the consequenc-es of different treatment options in patients with idiopathic scoliosis, it is still not clear which approach (conservative or surgical) has more influence on controlling curve pro-gression. The aim of this study was to compare the final results of scoliotic treatment using each approach. A search was conducted using appropriate key words in identified data bases including PubMed; ISI web of knowledge; Google scholar; Ebsco and Em-base. Data extraction was done using PICO (population, intervention, comparison and outcomes). Finally, the ‘Down and Black’ tool was used to assess the quality of selected studies. The initial search strategy yielded fifty studies. 9 studies were included for final analysis in this review. Studies were categorized as those which reported the number of scoliotic subjects treated with an orthosis who also had surgery and studies comparing outcomes of treatment modalities (surgery and conservative treatment (orthosis)). Re-sults of this review indicated that orthotic treatment can control the rate of surgery in sco-liotic subjects. Literature comparing between orthotic and surgical management focused mostly on specific parameters such as quality of life; well-being and pulmonary function. These parameters, demonstrated no significant difference between scoliotic subjects treated with surgery and bracing.

Outcome of Conservative Therapy of Adolescent Idiopathic Scoliosis (AIS) with Chêneau-Brace

Chêneau-brace (C-Brace) is a potential tool for the treatment of adolescent idiopathic scoliosis (AIS) with a Cobb angle between 20° and 45° for the primary curve. The aim of the present study was (1) to estimate study cohorts with C-brace therapy success and therapy failure and (2) to analyze possible factors that influence the therapy outcome. Seventy-eight patients with AIS were assessed before the initiation of C-brace treatment. Each patient underwent radiography examinations before the brace, in-brace, and at the therapy end. Cobb angle was considered as increased when the value at the end of therapy was increased more than 5° (Δ > 5°), unchanged-when the value was unchanged within ± 5° and decreased- when the value was decreased more than 5° (Δ < -5°). The study cohort was stratified due to curve topography in the thoracic, thoracolumbar, and lumbar scoliosis groups. Global analysis revealed no statistically significant modification of the Cobb angle (Cobb angle pre-brace vs. Cobb angle post-brace: 30.8° ± 8.2 vs. 29.3° ± 15.2, p = 0.26). However, at the end of C-brace therapy, the primary Cobb angle was decreased by more than 5° in 27 patients (35%), unchanged (Δ within the range of ±5°) in 36 patients (46%), and increased more than 5° in 15 patients (19%). Sub-group analysis due to curve topography and skeletal maturity has shown higher rates of brace therapy failure in thoracic curves and in younger patients (Risser grade 0). Patients with higher Cobb angle correction with C-brace had lower rates of therapy failure. The C-brace can be useful for the prevention of scoliotic curve progression in patients with AIS. However, many factors influence the therapy effect.

Patient-specific finite element modeling of scoliotic curve progression using region-specific stress-modulated vertebral growth

PurposeThis study describes the creation of patient-specific (PS) osteo-ligamentous finite element (FE) models of the spine, ribcage, and pelvis, simulation of up to three years of region-specific, stress-modulated growth, and validation of simulated curve progression with patient clinical angle measurements. Research Question: Does the inclusion of region-specific, stress-modulated vertebral growth, in addition to scaling based on age, weight, skeletal maturity, and spine flexibility allow for clinically accurate scoliotic curve progression prediction in patient-specific FE models of the spine, ribcage, and pelvis?MethodsFrontal, lateral, and lateral bending X-Rays of five AIS patients were obtained for approximately three-year timespans. PS-FE models were generated by morphing a normative template FE model with landmark points obtained from patient X-rays at the initial X-ray timepoint. Vertebral growth behavior and response to stress, as well as model material properties were made patient-specific based on several prognostic factors. Spine curvature angles from the PS–FE models were compared to the corresponding X-ray measurements.ResultsAverage FE model errors were 6.3 ± 4.6°, 12.2 ± 6.6°, 8.9 ± 7.7°, and 5.3 ± 3.4° for thoracic Cobb, lumbar Cobb, kyphosis, and lordosis angles, respectively. Average error in prediction of vertebral wedging at the apex and adjacent levels was 3.2 ± 2.2°. Vertebral column stress ranged from 0.11 MPa in tension to 0.79 MPa in compression.ConclusionIntegration of region-specific stress-modulated growth, as well as adjustment of growth and material properties based on patient-specific data yielded clinically useful prediction accuracy while maintaining physiological stress magnitudes. This framework can be further developed for PS surgical simulation.

Current Aspects on the Pathophysiology of Bone Metabolic Defects during Progression of Scoliosis in Neurofibromatosis Type 1.

Neurofibromatosis type 1 (NF1), which is the most common phacomatoses, is an autosomal dominant disorder characterized by clinical presentations in various tissues and organs, such as the skin, eyes and nervous and skeletal systems. The musculoskeletal implications of NF1 include a variety of deformities, including scoliosis, kyphoscoliosis, spondylolistheses, congenital bony bowing, pseudarthrosis and bone dysplasia. Scoliosis is the most common skeletal problem, affecting 10–30% of NF1 patients. Although the pathophysiology of spinal deformities has not been elucidated yet, defects in bone metabolism have been implicated in the progression of scoliotic curves. Measurements of Bone Mineral Density (BMD) in the lumbar spine by using dual energy absorptiometry (DXA) and quantitative computer tomography (QCT) have demonstrated a marked reduction in Z-score and osteoporosis. Additionally, serum bone metabolic markers, such as vitamin D, calcium, phosphorus, osteocalcin and alkaline phosphatase, have been found to be abnormal. Intraoperative and histological vertebral analysis confirmed that alterations of the trabecular microarchitecture are associated with inadequate bone turnover, indicating generalized bone metabolic defects. At the molecular level, loss of function of neurofibromin dysregulates Ras and Transforming Growth factor-β1 (TGF-β1) signaling and leads to altered osteoclastic proliferation, osteoblastic activity and collagen production. Correlation between clinical characteristics and molecular pathways may provide targets for novel therapeutic approaches in NF1.

Systematic Review of Reciprocal Changes after Spinal Reconstruction Surgery : Do Not Miss the Forest for the Trees.

The purpose of this review was to synthesize the research on global spinal alignment and reciprocal changes following cervical or thoracolumbar reconstruction surgery. We carried out a search of PubMed, EMBASE, and Cochrane Library for studies through May 2020, and ultimately included 11 articles. The optimal goal of a truly balanced spine is to maintain the head over the femoral heads. When spinal imbalance occurs, the human body reacts through various compensatory mechanisms to maintain the head over the pelvis and to retain a horizontal gaze. Historically, deformity correction has focused on correcting scoliosis and preventing scoliotic curve progression. Following substantial correction of a spinal deformity, reciprocal changes take place in the flexible segments proximal and distal to the area of correction. Restoration of lumbar lordosis following surgery to correct a thoracolumbar deformity induces reciprocal changes in T1 slope, cervical lordosis, pelvic shift, and lower extremity parameters. Patients with cervical kyphosis exhibit different patterns of reciprocal changes depending on whether they have head-balanced or trunk-balanced kyphosis. These reciprocal changes should be considered to in order to prevent secondary spine disorders. We emphasize the importance of evaluating the global spinal alignment to assess postoperative changes.

Scoliosis Screening.

The national recommendations for school screening programs for scoliosis in the United States have undergone a shift in perspective over the past two decades. In 2004, the United States Preventive Services Task Force recommended against screening programs but changed its recommendation to be inconclusive in 2018. Early diagnosis of scoliosis can allow for close monitoring of the deformity and early initiation of bracing treatment when appropriate, with the goal of preventing costly and invasive surgical intervention. Several different diagnostic tools are available, including Adam's forward bending test alone, Adam's forward bending test with scoliometry, the humpometer, and Moiré topography, each with varying degrees of sensitivity and specificity. Controversy prevails over the cost efficacy of screening programs and possible unnecessary exposure of adolescents to radiation for confirmatory radiographs after a positive screening test. However, the recent definitive evidence of bracing treatment efficacy in slowing the progression of scoliotic curves and preventing the need for surgery indicates that school screening programs may still have a role in allowing early diagnosis.

Evaluation of the effects of various force configurations and magnitudes on scoliotic curve correction by use of finite element analysis: A case study

Background: Scoliosis is a three-dimensional (3-D) spinal deformity that is associated with changes in the alignment of the spine in sagittal, frontal, and transverse planes. Various treatment approaches have been used to control scoliotic curve progression and decrease the curve. Although various braces have been used in this regard, it would be difficult to check the effects of multiple types of braces on scoliotic curve correction for each scoliotic patient. Therefore, the aim of this study was to evaluate the effects of various force magnitudes and configurations on scoliotic curve correction. Methods: A 3-D model of a scoliotic patient was produced based on CT scan images of the total spine. The scoliotic curves were 21 and 45 degrees in lumbar and thoracic parts, respectively. Mimics software was used to produce a 3-D model of the spine. The stress developed in the spine structure and the magnitude of correction achieved were evaluated following the use of various force configurations and magnitudes by use of finite element analysis (FEA). Results: The results of this analysis showed that vertical forces were more effective than transversely directed forces in decreasing scoliotic curve. There was an inverse relationship between the corrections of lumbar and thoracic curves. However, use of vertically directed forces decreased both lumbar and thoracic curves. An increase in the magnitude of transverse forces did not increase the correction, but it did increase the stress developed in the structure. Conclusions: The results of this case study confirmed the efficiency of vertically directed forces to decrease scoliotic curves of lumbar and thoracic spinal parts. The results of this analysis confirmed the results of the available literature, which support the efficiency of some braces such as Boston, Lyon, and Cheneau, which were mostly designed based on full contact and vertical traction. The results of this study also support the feasibility of finite element analysis to predict the output of brace treatment by use of various force configurations. Level of Evidence: Level IV.

Evaluation of the efficacy of part-time versus full-time brace wear in subjects with adolescent idiopathic scoliosis (AIS): a review of literature

Background: Scoliosis is a musculoskeletal disorder that can be managed by wearing an orthosis full or part time. It is not well understood whether the effectiveness of part-time orthotic management of spinal curve progression is as efficacious as full-time wear. The aim of this review was to determine the efficiency of part-time bracing (with a focus on night-time braces), compared to full-time bracing. Moreover, the study aimed to determine which part-time brace demonstrated the most efficacy. Method: A literature review was conducted via a Medline search in PubMed, ISI Web of knowledge, Scopus, Ebsco, Embasco, and Google Scholar. Key words (part time, night braces) were used in combination with adolescent idiopathic scoliosis. The quality of the selected papers was evaluated based on the Downs and Black tool. Results: Fifty papers were found. Following application of inclusion and exclusion criteria based on titles and abstracts, 19 papers were selected for final analysis. These papers were divided into three categories: (1) evaluation of the efficacy of night braces on progression of scoliotic curve (seven papers); (2) Comparison of efficacy between night and full-time bracing (10 studies); and (3) three-dimensional modeling and finite element analysis of part-time bracing. Conclusions: The Providence brace appears to provide an effective treatment approach to influence curve progression in scoliotic patients. However, it should be emphasized that its maximal effect is for lumbar, lumbosacral, and thoracic curves with a low apex. It is recommended to use the Charleston Bending brace only for patients with a single scoliotic curve. The efficacy of full-time bracing for double curves, thoracolumbar curves, and curves more than 35 degrees indicates that more than just a night brace is necessary. However, it seems that there is no difference between the effects of part-time and full-time bracing for curves of smaller magnitude (less than 35 degrees).

Correlation between compliance and brace treatment in juvenile and adolescent idiopathic scoliosis: SOSORT 2014 award winner.

BackgroundOver the last years, evidence has accumulated in support of bracing as an effective treatment option in patients with idiopathic scoliosis. Yet, little information is available on the impact of compliance on the outcome of conservative treatment in scoliotic subjects. The aim of the present study was to prospectively evaluate the association between compliance to brace treatment and the progression of scoliotic curve in patients with idiopathic adolescent (AIS) or juvenile scoliosis (JIS).MethodsAmong 1.424 patients treated for idiopathic scoliosis, 645 were eligible for inclusion criteria. Three outcomes were distinguished in agreement with the SRS criteria: curve correction, curve stabilization and curve progression. Brace wearing was assessed by one orthopaedic surgeon (LA) and scored on a standardized form. Compliance to treatment was categorized as complete (brace worn as prescribed), incomplete A (brace removed for 1 month), incomplete B (brace removed for 2 months), incomplete C (brace removed during school hours), and incomplete D (brace worn overnight only). Chi square test, T test or ANOVA and ANOVA for repeated measures tests were used as statistical tests.ResultsThe results from our study showed that at follow-up the compliance was: Complete 61.1%; Incomplete A 5.2%; Incomplete B 10.7%; Incomplete C 14.2%; Incomplete D 8.8%. Curve correction was accomplished in 301/319 of Complete, 19/27 Incomplete A, 25/56 Incomplete B, 52/74 Incomplete C, 27/46 Incomplete D. Cobb mean value was 29.8 ± 7.5 SD at beginning and 17.1 ± 10.9 SD at follow-up. Both Cobb and Perdriolle degree amelioration was significantly higher in patients with complete compliance over all other groups, both in juvenile, both in adolescent scoliosis. In the intention-to-treat analysis, the rate of surgical treatment was 2.1% among patients with definite outcome and 12.1% among those with drop-out. Treatment compliance showed significant interactions with time.ConclusionCurve progression and referral to surgery are lower in patients with high brace compliance. Bracing discontinuation up to 1 month does not impact on the treatment outcome. Conversely, wearing the brace only overnight is associated with a high rate of curve progression.

Selective estrogen receptor modulation prevents scoliotic curve progression: radiologic and histomorphometric study on a bipedal C57Bl6 mice model

Previous work has suggested that progression of experimental scoliotic curves in pinealectomized chicken and bipedal C57BL6 mice models may be prevented and reversed with Tamoxifen treatment. Raloxifene is another Selective Estrogen Receptor Modulator (SERM) with estrogen agonist effects on bone and increases bone density but with fewer side effects on humans. To investigate whether scoliosis progression in bipedal C57Bl6 mice model could be prevented with SERM treatment and the mechanisms associated with this effect. Eighty C57BL6 mice were rendered bipedal and divided into Tamoxifen (TMX), Raloxifene (RLX) and control groups. TMX and RLX groups received orally administered TMX and RLX for 40weeks. Anteroposterior X-ray imaging and histomorphometric analysis (at 20th and 40th weeks) were performed. At 20th week, TMX and RLX groups displayed higher rates (p=0.033, p=0.029) and larger curve magnitudes (p=0.018). At 40th week, curve rates were similar between the groups but the curve magnitudes in TMX and RLX groups were smaller (p=0.001). Histomorphometry revealed that treated animals had higher trabecular density (p=0.04), lower total intervertebral disc (p=0.038) and growth plate volumes (p=0.005) and smaller vertebral bodies (p=0.016). Treatment with TMX or RLX did not reduce the incidence of scoliosis but decreased the curve magnitudes at 40weeks. The underlying mechanism associated with the decrease in curve magnitudes may be the early maturation of growth plates, thereby possible deceleration of the growth rate of the vertebral column and increase in bone density. RLX is as effective as TMX in preventing the progression of scoliotic curves in melatonin deficient bipedal mice.

Surgical management of spinal deformities in cerebral palsy

Cerebral palsy (CP) spinal deformities encompass a spectrum of deformities that are often initially treated nonoperatively, only to result in progression of scoliotic curves and further morbidity. Various surgical interventions have been devised to address the progressive curvature of the spine. This endeavor cannot be taken lightly and at times can be encumbered by prior treatments such as the use of baclofen pumps or dorsal rhizotomies. Care of these patients requires a multidisciplinary approach and comprehensive preoperative and postoperative management, including nutritional status, orthopedic assessment of functional level with specific emphasis on the hips and pelvic obliquity, and wheelchair modifications. The surgical techniques in CP scoliosis have progressively evolved from the classic Luque-Galveston fixation methods, the use of unit rods, and lately the use of pedicle screws, to modern sacropelvic fixation. With the latter method, the spinal deformity in patients with CP can usually be almost completely corrected.

Convex side muscular activity and progression of scoliotic curve

Muscular asymmetry is considered as important etiological factor of idiopathic scoliosis. The present study analyses pathomechanisms leading to progression of scoliotic deformation as the result of asymmetric paraspinal muscular activity irrespective of the primary trigger.

Pediatric scoliosis predictive blood tests: progress and challenges for clinicians

Purpose There are great needs for innovative pharmacotherapies in combination with clinical tests to identify asymptomatic children at risk of developing scoliosis and symptomatic ones to predict who may be at risk of scoliotic curve progression. Early detection of scoliosis is critical to broaden the range of treatment options and increases effectiveness. Currently, there are no FDA cleared “presymptomatic” diagnostic tests available for assessing scoliosis in paediatric patients. We have developed a cell-based screening assay for the early diagnosing of presymptomatic subjects and a biochemical blood test for asymptomatic individuals and patients at different disease stage.

The role of spinal concave–convex biases in the progression of idiopathic scoliosis

Inadequate understanding of risk factors involved in the progression of idiopathic scoliosis restrains initial treatment to observation until the deformity shows signs of significant aggravation. The purpose of this analysis is to explore whether the concave-convex biases associated with scoliosis (local degeneration of the intervertebral discs, nucleus migration, and local increase in trabecular bone-mineral density of vertebral bodies) may be identified as progressive risk factors. Finite element models of a 26 degrees right thoracic scoliotic spine were constructed based on experimental and clinical observations that included growth dynamics governed by mechanical stimulus. Stress distribution over the vertebral growth plates, progression of Cobb angles, and vertebral wedging were explored in models with and without the biases of concave-convex properties. The inclusion of the bias of concave-convex properties within the model both augmented the asymmetrical loading of the vertebral growth plates by up to 37% and further amplified the progression of Cobb angles and vertebral wedging by as much as 5.9 degrees and 0.8 degrees, respectively. Concave-convex biases are factors that influence the progression of scoliotic curves. Quantifying these parameters in a patient with scoliosis may further provide a better clinical assessment of the risk of progression.

Suboccipital decompression for Chiari malformation–associated scoliosis: risk factors and time course of deformity progression

Chiari malformation Type I (CM-I) is often associated with scoliosis. It remains unclear which subgroups of patients are most likely to experience progression of spinal deformity after cervicomedullary decompression. The authors' goal was to determine the time frame of curvature progression and assess which patient subgroups are at greatest risk for progression of spinal deformity after surgery. The authors retrospectively reviewed the records of all pediatric patients with significant scoliosis in whom suboccipital decompression was performed to treat for CM-I during a 10-year period at a single academic institution. Clinical, radiological, and operative variables were assessed as independent factors for failure (worsening of scoliosis) by using a univariate regression analysis. Twenty-one children (mean age 9 +/- 3 years; 4 male) underwent hindbrain decompression for CM-I-associated scoliosis and were followed for a mean of 39 months. All patients harbored a syrinx. Eight patients (38%) experienced improvement in scoliosis curvature, whereas 10 (48%) suffered a progression. Thoracolumbar junction scoliosis (p = 0.04) and failure of the syrinx to improve (p = 0.05) were associated with 5- and 4-fold respective increases in the likelihood of deformity progression. Each increasing degree of preoperative Cobb angle was associated with an 11% increase in the likelihood of scoliotic curve progression (p < 0.05). Over one third of patients with CM-I-associated scoliosis will improve after cervicomedullary decompression alone. Cervicomedullary decompression is a good first-line option, particularly in children with concordant posterior fossa symptoms. Patients presenting with more severe scoliosis (increasing Cobb angle) or scoliosis that crosses the thoracolumbar junction may benefit from earlier orthopedic involvement and should be monitored regularly for curvature progression after cervicomedullary decompression. In cases in which there is a failure of the syrinx to show improvement after suboccipital decompression, the patients are also more likely to develop curvature progression.

Progression of Scoliosis in Patients With Spastic Quadriplegia After the Insertion of an Intrathecal Baclofen Pump

Medical and radiographic review of 19 consecutive patients with spastic quadriplegia before and after intrathecal baclofen pump insertion with special attention paid to progression of scoliosis. Many orthopedic surgeons who treat spastic quadriplegic patients have noticed a trend of marked scoliosis progression after the administration of intrathecal baclofen (ITB) via subcutaneous pump and catheter. The purpose of this study is to quantify scoliosis progression in this patient population before and after baclofen administration and compare this to published natural history data. The authors had noted rapid progression of scoliosis in spastic quadriplegic patients after intrathecal baclofen pump insertion. This had been noted at other centers, but no significant statistical analysis had been done comparing prepump to postpump scoliosis progression in these patients. To document the magnitude and rate of scoliosis progressions after the placement of an ITB pump, the charts and radiographs of 19 consecutive nonambulatory patients with spastic quadriplegia and an ITB pump were reviewed. To document the rate of scoliosis progression, each patient had at least 2 pre and 2 postpump insertion spinal radiographs made. All radiographs were made with the patients in the supine position without orthoses. A board-certified orthopedic surgeon reviewed these radiographs. Skeletal maturity was assessed using Risser grading. Catheter tip location and rate of baclofen administration were recorded. For 19 patients with complete radiographic data, average Cobb angles were 10.2 degrees before pump insertion and 25 degrees at an average of 20.9 months after pump insertion (P < 0.0001). These 19 patients had a mean rate of change in their Cobb angles of 1.825%/year before pump insertion and 10.95 degrees /year at an average of 23.9 months after pump insertion (P = 0.024). These results represent a 6-fold increase in the curve progression rate after pump insertion. There was no association between catheter tip location or rate of Baclofen infusion on curve progression. In published data, the rate of progression of scoliosis in skeletally immature nonambulatory patients with cerebral palsy was 4.5 degrees /year. In this study, the average rate of progression of the scoliosis for the immature was 9.02 degrees /year. For the skeletally mature bed-ridden patients, the worst-case natural history progression was 4.4 degrees /year. The comparable rate of change in skeletally mature (Risser 5) nonambulatory patients (n = 6) in this study was 28.4 degrees /year. This study demonstrates a significant increase in the rate of scoliotic curve progression after ITB pump placement when compared with published natural history data. The evidence of the beneficial effects of ITB on spasticity has been confirmed, and as larger, prospective randomized studies are conducted, the authors think that support for continued use of this treatment will increase. However, early bracing and spinal fusion may be warranted to prevent significant increases in spinal deformity if scoliosis is anticipated to progress more than 10 degrees /yr for patients with spastic quadriplegia and ITB pump. The authors are now performing spinal fusions for curves that exceed 40 degrees to 50 degrees in the presence of an ITB pump as recommended by previous reviews of scoliosis and accompanying quadriplegia.

Upright posture impact on spine susceptibility in scoliosis and progression patterns of scoliotic curve

To investigate the impact of upright posture on spine susceptibility in scoliosis and scoliotic curve progression patterns. There were 3 groups designed in the experiment: bipedal rats group (n = 26), quadrupedal rats group (n = 26) and sham operation bipedal control (n = 12). Taking the advantage of bipedal rats' upright-posture simulating effect, operations were exerted with posterior central approach between scapulas. Along the spatial of erector spinae muscle and trunk muscles, left side upper (T2-3 or T3-4) and lower (T10-11 or 11 - 12) ribs were tethered with type4 thread to make asymmetrical stress and simulate a primary thoracic curve. At time of 1, 2, 3, 4, 6 and 8 weeks post-operation (PO), each group were taken dorsoventral X-ray photographs for dynamic observation on the difference of scoliosis turnover and to compare the curvature progression difference between bipedal and quadrupedal rats. Operation resulted in a primary single thoracic curve or thoracolumbar curve convex to the right in both bipedal and quadrupedal rats. At 1 - 4 weeks PO, all asymmetrical tethers became loose because of rib fracture or osteolysis at the tether sites. All scoliosis of quadrupedal rats disappeared and spine resume straight in 1 - 4 weeks later. Analogically, scoliosis disappeared in bipedal rats for those tethers loose in 1 w PO. But prolonged tethering, scoliosis progression rates increased conspicuously. 3 - 4 weeks' tether time led to irreversible scoliosis. Meanwhile, the curvature progression patterns of bipedal rats presented to be various, including the stable single thoracic curve, progressive thoracolumbar single curve and progressive double curve. These curvatures were much alike that of human idiopathic scoliosis. No scoliosis appeared in sham operation bipedal control. The upright posture increased spinal susceptibility in scoliosis; Upright posture changes the progression pattern of scoliosis, leading to variegated scoliotic morphouses during primary thoracic curve progression, while inducing curve compensation phenomenon in scoliosis.

Relations between standing stability and body posture parameters in adolescent idiopathic scoliosis.

A retrospective study of standing imbalance and body posture in 71 able-bodied girls and subjects with adolescent idiopathic scoliosis was conducted. To test the hypothesis that postural parameters are related to standing stability parameters. Spinal deformity not only modifies the shape of the trunk, but also changes the relations between body segments affecting posture in scoliotic children. These postural adaptations to the scoliotic curve progression could be linked in part to increased body sway in upright standing. This has not yet been related to specific postural parameters involving the head, trunk, and pelvis in nontreated idiopathic scoliosis. The head, trunk, and pelvis orientations of each subject were measured by a Flock of Bird system. An AMTI force platform was used to assess quiet standing stability and to monitor the position and displacement of the center of pressure (COP). The center of mass (COM) excursion was estimated from a biomechanical model using force plate information only. Analyses of variance (ANOVAS) were performed to determine the statistical differences between the scoliotic and nonscoliotic subjects, and backward stepwise multiple regression analyses were performed to identify any correlation between measures of quiet standing stability and body postural parameters The scoliotic group was characterized by a decrease in standing stability. There was an increase in the sway areas measured by the variations of the COP and COM. From the backward stepwise multiple regression analysis, it appears that for the able-bodied girls, the body posture parameters were correlated only with the mean anteroposterior center of pressure (COP(AP)) position. For the scoliotic group, the sway areas and the mean position of the centers of pressure and the COP(AP)-COM(AP) were correlated significantly with body posture parameters. The higher COP-COM differences for the scoliotic group were attributed to a greater neuromuscular demand to maintain standing balance. The coefficients of correlation of the multiple regression analyses ranged from 0.64 to 0.85 for the nonscoliotic group and from 0.55 to 0.72 for the scoliotic group. The use of backward stepwise multiple correlations highlighted the interaction between several body parameters and their relation to standing stability in both able-bodied girls and scoliotic subjects. The scoliotic group displayed a much larger number of correlations between standing stability and body posture parameters than the nonscoliotic group. Standing imbalance was related to altered body posture parameters measured in the frontal and horizontal planes only. Although the correlation coefficients were relatively high, factors other than body posture parameters appeared related to standing imbalance in adolescent idiopathic scoliosis. These findings support the concept of either a primary or a secondary dysfunction in the postural regulation system of scoliotic subjects.

Continuous model of the human scoliotic spine

The human scoliotic spine is mathematically modelled by employing the classical non-linear theory of curved beam-columns. A realistically representative muscle force system is included in the model. Scoliosis due to asymmetrical bi-lateral musucular contractions has been studied and arbitrary large displacements and curvatures are allowed. The two-dimensional model allowing curvature in the frontal plane can show the progression of a scoliotic curve from an initially straight configuration. For various parameter values, particularly muscle asymmetry, the model attempts to simulate the progression of actual scoliotic curves. Onc these curves have been simulated, forces corresponding to corrective surgical systems are applied to the scoliotic spine. The corresponding corrected curves are then compared with those produced by a finite element model and also to the actual clinical curve. The comparisons were very favourable, considering the simplicity of the continuous model. The commonly observed phenomenon of the scoliotic curve lying to the weaker side of the back in terms of muscle strength is reproduced and explained by the model. The possible usefulness of continuous spinal models to analyse the overall deformation of the spine under various loading conditions can then be deduced.