Pathogenesis of idiopathic scoliosis revisited

Thoracolumbar fascia and chronic low back pain in idiopathic lumbar scoliosis: an ultrasonographic study

PURPOSE

The role of thoracolumbar fascia (TLF) in the development of chronic low back pain (CLBP) has growing evidence in the literature. Although CLBP is reported in individuals with idiopathic scoliosis (IS), its relationship with the TLF has yet not been established. This study aims to evaluate the TLF and its relationship with CLBP in IS.

METHODS

A total of 60 individuals were included in the study. They were divided into three groups as follows: painful scoliosis (n = 20, age: 17.1 ± 3.7 years, Cobb angle: 15-43°), non-painful scoliosis (n = 20, age: 16.4 ± 3.4 years, Cobb angle: 15-45°), and healthy group (n = 20, age: 16.4 ± 4.7 years). Pain was evaluated using the short form of the McGill Pain Questionnaire. TLF thickness was evaluated on the lumbar region using ultrasonography. Trunk range of motion was assessed using a universal goniometer, and flexibility was assessed with sit-and-reach test.

RESULTS

The thickness of the right TLF was greatest in the painful group, followed by non-painful (p = 0.007) and healthy (p < 0.001) groups. The thickness of the left TLF in the non-painful and painful groups was greater compared to the healthy group (p < 0.001). In the painful group, right TLF thickness was negatively correlated with trunk flexion/extension (r = -0.540, p = 0.014/r = -0.514, p = 0.020) and left rotation (r = -0.499, p = 0.025) but positively correlated with pain (r = 0.562, p = 0.01).

CONCLUSIONS

Thickening of the TLF was observed in IS, whereby, in the presence of CLBP, it was further intensified. We suggest considering fascial thickening as a potential contributing factor to both pain and limited motion in relevant patients.

Finite element method-based study for spinal vibration characteristics of the scoliosis and kyphosis lumbar spine to whole-body vibration under a compressive follower preload

PURPOSE

To analyze the dynamic response of the lumbosacral vertebrae structure of a scoliosis spine and a kyphosis spine under whole-body vibration.

METHODS

Typical Lenke4 (kyphosis) and Lenke3 (scoliosis) spinal columns were used as research objects. A finite element model of the lumbosacral vertebrae segment was established and validated based on CT scanning images. Modal, harmonic response, and transient dynamic analyses were performed on the lumbar-sacral scoliosis model using the finite element software abaqus.

RESULTS

The first four resonance frequencies of kyphosis spine extracted from modal analysis were 0.86, 1.45, 8.51, and 55.71 Hz. The first four resonance frequencies of scoliosis spine extracted from modal analysis were 0.76, 1.45, 10.51, and 63.82 Hz. The scoliosis spine had the maximum resonance amplitude in the transverse direction, while the kyphosis spine had the maximum resonance amplitude in the anteroposterior direction. The dynamic response in transient analysis exhibited periodic response over time at all levels.

CONCLUSION

The scoliosis and kyphosis deformity of the spine significantly complicates the vibration response in the scoliosis and kyphosis areas at the top of the spine. Scoliosis and kyphosis patients are more likely to experience vibrational spinal diseases than healthy people. Besides, applying vertical cyclic loads on a malformed spine may cause further rotation of scoliosis and kyphosis deformities.

Biodynamic responses of adolescent idiopathic scoliosis exposed to vibration

Patients with adolescent idiopathic scoliosis suffer severe health issues. The unclear dynamic biomechanical characteristics of scoliosis were needed to be explored to improve the prevention and treatment in clinics. Validated 3D finite element (FE) models of thoracolumbosacral spine (T1-S1) both with and without scoliosis were developed from computed tomography (CT) images. Modal and harmonic analyses were performed to investigate the biomechanical responses of the spinal models to vibration. Resonant frequencies of the scoliotic model were lower than those of the model without scoliosis. Peak amplitudes occurred at vibrational frequencies close to the modal resonant frequencies, which caused the deformed thoracic segment in scoliosis suffered the maximum amplitude. The stresses on vertebrae and intervertebral discs in the scoliotic model derived from vibrations were significantly larger than those in the non-scoliosis model, and heterogeneously concentrated on the scoliotic thoracic segment. In conclusion, the scoliotic spine in the patients with Lenke 1BN scoliosis is more prone to injuries than the non-scoliotic spine while vibrating. Scoliotic thoracic segments in patients with Lenke 1BN scoliosis were the more vulnerable and sensitive component of the T1-S1 spine to vibration than lumbar spines. This study suggested that vibration would impair the scoliotic spines, and patients with Lenke 1BN scoliosis should avoid exposure to vibration, especially the low-frequency vibration.

Development and Validation of a Whole Human Body Finite Element Model with Detailed Lumbar Spine

OBJECTIVE

Investigations showed that low back pain of occupational drivers might be closely related to the whole-body vibration. Restricted by ethical concerns, the finite element method had become a viable alternative to invasive human experiments. Many mechanical behaviors of the human spine inside of the human body were unclear; therefore, a human whole-body finite element model might be required to better understand the lumbar behavior under whole-body vibration.

METHODS

In this study, a human whole-body finite element model with a detailed lumbar spine segment was developed. Several validations were performed to ensure the correctness of this model.

RESULTS

The results of anthropometry and geometry validation, static validation, and dynamic validation were presented in this study. The validation results showed that the whole human body model was reasonable and valid by comparing with published data.

CONCLUSIONS

The model developed in this study could reflect the biomechanical response of the human lumbar spine under vibration and could be used in further vibration analysis and offer proposals for protecting human body under whole-body vibration environment.

Reduction of Adolescent Idiopathic Scoliosis and Improved Z-Axis Alignment of the Entire Spine When Treating a Symptomatic Patient Using a Multidisciplinary Approach: A Case Report

Background

This study presents findings on improvements of both the X-axis and Z-axis posture in a young female with adolescent idiopathic, scoliosis suffering from pain complaints who was treated with a multidisciplinary approach.

Case Presentation

The 15-year-old patient reported low back pain for several months. Full spine radiographic assessment revealed a cervical kyphosis, forward head translation, a right ribcage translation, a left higher shoulder, and a dextroconvex lumbar scoliosis with a Cobb angle of 23°. The patient was treated with novel ASPINE Systems treatment protocols incorporating posture exercises, muscle balancing exercises, spinal 3D traction, and spinal manipulation.

Results

Assessment after 50 treatment sessions over 32 weeks revealed a dramatic improvement in postural distortions. The cervical kyphosis was reduced by 9° and was accompanied by a reduction in forward head posture, centering of the thoracic spine, leveling off her shoulders, and a reduction in the dextroconvex scoliosis by 10°. The lower back pain was relieved.

Conclusion

A reduction of postural distortions including idiopathic adolescent scoliosis resulted from a multidisciplinary approach utilizing ASPINE Systems.

Influence of Etiology and Onset of Deformity on Spatiotemporal, Kinematic, Kinetic, and Electromyography Gait Variables in Patients with Scoliosis-A Prospective, Comparative Study

STUDY DESIGN

Prospective comparative study.

OBJECTIVE

The aim of this study was to compare the spatiotemporal, kinematic, kinetic and electromyographic (EMG) gait variables in patients with adolescent idiopathic scoliosis (AIS) and congenital scoliosis and to compare these gait variables of scoliosis patients with healthy controls.

SUMMARY OF BACKGROUND DATA

Earlier studies have solely focussed on the possibility of altered gait patterns in AIS patients; not much light has been shed on the differences in gait patterns in congenital and adolescent scoliosis patients.

METHODS

Forty scoliosis patients (20 each with AIS and congenital scoliosis) and 20 healthy volunteers were prospectively recruited. After thorough clinical and radiological examination, all patients underwent gait analysis in accordance with standard protocols.The outcome measures included spatiotemporal, kinetic, kinematic and EMG activity. Composite indices for gait analysis-Gait Profile Score (GPS) and Gait Deviation Index (GDI)-were also calculated. Relevant statistical tests were applied to compare the different groups.

RESULTS

No significant difference was found between the AIS and congenital scoliosis groups with respect to baseline demographic and radiological parameters. The two subgroups of scoliosis patients (AIS and congenital) did not differ significantly with respect to any of the measured gait analysis parameters. However, when compared to the healthy age-matched control group, the scoliosis patients differed significantly with respect to gait speed, stride length, step length, GDI, GPS and peak EMG activation for erector spinae, biceps femoris, semimembranosus, rectus femoris, gastrocnemious, and tibialis anterior.

CONCLUSION

Our findings confirm the previous findings of literature regarding the alteration in gait patterns in scoliosis patients when compared to normal individuals. However, the lack of difference in gait analysis variables between AIS and congenital scoliosis patients suggests that this alteration in gait is secondary to the existence of the deformity and does not correlate with the onset or etiology of deformity.Level of Evidence: 2.

The influence of the rib cage on the static and dynamic stability responses of the scoliotic spine

The thoracic cage plays an important role in maintaining the stability of the thoracolumbar spine. In this study, the influence of a rib cage on static and dynamic responses in normal and scoliotic spines was investigated. Four spinal finite element (FE) models (T1-S), representing a normal spine with rib cage (N1), normal spine without rib cage (N2), a scoliotic spine with rib cage (S1) and a scoliotic spine without rib cage (S2), were established based on computed tomography (CT) images, and static, modal, and steady-state analyses were conducted. In S2, the Von Mises stress (VMS) was clearly decreased compared to S1 for four bending loadings. N2 and N1 showed a similar VMS to each other, and there was a significant increase in axial compression in N2 and S2 compared to N1 and S1, respectively. The U magnitude values of N2 and S2 were higher than in N1 and S1 for five loadings, respectively. The resonant frequencies of N2 and S2 were lower than those in N1 and S1, respectively. In steady-state analysis, maximum amplitudes of vibration for N2 and S2 were significantly larger than N1 and S1, respectively. This study has revealed that the rib cage improves spinal stability in vibrating environments and contributes to stability in scoliotic spines under static and dynamic loadings.

Lumbar Scoliosis Induction in Juvenile Dogs by Three-dimensional Modulation of Spinal Growth Using Nickel-Titanium Coil Springs

Background:

Current treatments for scoliosis have some defects and complications. To study spinal deformities and test novel scoliosis treatments, many animal models of scoliosis have been developed. These models applied a single load to the spine and could not precisely modulate the spinal growth in different dimensions. In this study, we applied posterior tethering in various directions with the application of nickel-titanium (NT) coil springs in dog's spine to modulate spinal growth in the coronal, sagittal, and transverse planes and create a scoliosis model possess curves that mimic adolescent idiopathic scoliosis (AIS) three dimensionally.

Methods:

Scoliosis was surgically induced in eight 8-week-old female dogs (weight: 1.95–2.30 kg) using bone screws and NT coil springs. The deformity was induced through the placement of posterior NT coil springs that tethered the spine by bone screw fixation. All dogs were monitored with serial radiographs to document changes in deformities.

Results:

All experimental animals developed scoliotic curves convex to the left in the lumbar segment. The mean coronal Cobb angle was 18.0° immediately postoperatively and 54.5° at 22 weeks. The mean lordosis increased from 6.2° postoperatively to 35.0° at final follow-up. Apical axial rotation increased from 4.5° postoperatively to 31.2° at 22 weeks.

Conclusions:

With the application of NT springs in dogs that allowed posterior tethering in various directions, lumbar spinal deformity was achieved in three planes: coronal, sagittal, and transverse planes. Notably, the lumbar spine in surgically treated dogs developed lordoscoliosis with obvious rotation and the curves mimic AIS three dimensionally well. This method allows lumbar scoliosis to develop without deep dissection of muscle and maintains the essential anatomical elements along the spinal curve. Moreover, the spinal growth modulation technique could yield information that would provide a basis for developing novel early-stage treatments for children with scoliosis.

Scoliosis deformity reduction in adults: a CBP® Mirror Image® case series incorporating the 'non-commutative property of finite rotation angles under addition' in five patients with lumbar and thoraco-lumbar scoliosis

[Purpose] This case series presents the unique application of the non-commutative property of finite rotation angles under addition to the CBP^® mirror image^® treatment protocol for adult lumbar and thoraco-lumbar scoliosis. [Subjects and Methods] Five adult patients having lumbar/thoraco-lumbar scoliosis and back pain, and having at least two prominent thoracic postural abnormalities according to Harrison’s rotations and translations of thoracic postures were included. After initial assessment, mirror-image stress x-rays were taken. For each patient, one stress film was taken using the order of mirror image movements with the largest displacement followed by the second largest (primary + secondary) and one stress film was taken in the opposite order (secondary + primary). The consecutive ordered movements that resulted in the largest reduction of curvature were chosen as the order-specific series of movements all exercises and postural traction were to be performed for each patient. Spinal manipulation was also performed. [Results] All patients had a reduction of curvature concomitant with a reduction in pain levels. [Conclusion] This unique treatment approach offers a patient-specific, targeted structural rehabilitative procedure to stress the spine towards a more straightened configuration. Adult lumbar and thoraco-lumbar curves can be reduced and improved by these non-invasive CBP methods.

Finite element method-based study for effect of adult degenerative scoliosis on the spinal vibration characteristics

Finite element analysis was used to investigate the responses of five healthy subjects and five adult degenerative scoliosis (ADS) subjects to cyclic vibration. The dynamic responses of the healthy and scoliotic spines to the sinusoidal cyclic vibrations have been investigated in previous studies by simulation or experimental approaches. However, no simulation or experimental results were available for the ADS subjects. The effect of the ADS on the vibrational characteristics of spines remained unknown. The objective of this study was to compare differences of the dynamic responses to the cyclic vibration input between the healthy subjects and subjects with ADS. Based on the simulations results in this study, the scoliotic spines are more sensitive to the cyclic vibrations than the healthy spines. More resonant frequencies were predicted in the scoliotic spines than the healthy spines. The scoliotic deformity in the spine was to make the vibrational response of the spine significantly more complex at the apical scoliotic region. This study suggested that ADS could severely increase spinal response to the cyclic vibrations, which could potentially lead to further scoliotic deformity in the spine.

Novel experimental scoliosis model in immature rat using nickel-titanium coil spring

STUDY DESIGN

Follow-up of animals after surgically initiated scoliosis.

OBJECTIVE

To develop quantitatively asymmetric loads on rat lumbar to create scoliosis.

SUMMARY OF BACKGROUND DATA

Current animal models for scoliosis use mostly rigid or flexible posterior asymmetric tethers. The curve progression can only be expected for the growth potential, leading to insufficient growth potential for validation of corrective techniques.

METHODS

Scoliosis was induced in 55 five-week-old female Sprague-Dawley rats using a nickel-titanium coil spring. The experimental rats were randomly divided into 2 groups: in group A (n = 15), the nickel-titanium coil spring was not removed until these rats reached physical maturity (age, 12 wk). Group B (n = 40) was further randomly subdivided into 5 subgroups (n = 8 for each subgroup): removal of the spring after 1 week (group B1), 2 weeks (group B2), 3 weeks (group B3), 4 weeks (group B4), and 5 weeks (group B5). All rats were followed for a 7-week period with serial radiographs to document change of the deformity.

RESULTS

All experimental animals of group A developed progressive, structural scoliotic curves convex to the left in the lumbar segment. In group B, the deformity of the lumbar progressed after the spring load was applied and regressed after the spring was removed. The scoliosis in group B1-B3 (the spring removed before sexual maturity) regressed after spring removal until the rats reached sexual maturity (4 wk after spring implant surgery). The scoliosis in group B4-B5 (the spring removed after sexual maturity) regressed only during the first week after spring removal surgery. The average coronal Cobb angle was 7.8° ± 1.3° (range: 6.0° -10.2°) in group B1 at the final follow-up, and there was only 1 experimental rat that maintained a curve more than 108. The models of group B2-B5 maintained stable scoliotic curves (coronal Cobb angle of L2-L5 > 10°) convex to the left in the lumbar segment at the final follow-up.

CONCLUSION

This study establishes a rat lumbar scoliosis model via asymmetric load. This method develops lumbar scoliosis in a short time and maintains the essential elements along the curve. It is suitable for the investigation of scoliosis.

Systemic connective tissue abnormalities in patients with saccular intracranial aneurysms

OBJECTIVES

Our purpose was to identify the incidence and significance of markers of systemic connective tissue abnormalities (CTA) in patients with saccular intracranial aneurysms (SIA).

MATERIALS AND METHODS

This prospective case-control study included 199 consecutive patients with SIA (103 women and 96 men, mean age - 43.2 years) and 194 control patients - blood donors (108 - men, 86 - women, mean age - 38.4 years). Aneurysms were verified by conventional cerebral angiography. All patients were examined by the first author using a specially designed questionnaire and a standardized physical examination with special emphasis on systemic CTA.

RESULTS

Twelve markers of systemic CTA were significantly higher in patients with SIA than in controls: visible vessels on face and chest (59.8%), scoliosis (44.7%), varicose veins in legs (39.7%), flatfoot (34.6%), hyperextensibility of the skin (33.6%), spontaneous epistaxis (25.6%), easy bruising (20.6%), abdominal hernia (13.6%), periodontal disease (10.5%), chest deformations (7.5%), abdominal striae (3.5%), joint hypermobility (2.5%). A blinded validation study in a subset of 43 patients showed similar results. Among patients with SIA, 125 of 199 patients (62.8%) had at least three markers of systemic CTA compared with 23 (11.8%) of the controls (P < 0.0001, OR = 12.5, 95% CI 7.45-21.1). The mean number of markers of systemic CTA in patients with SIA was 3.07 and 1.17 in controls.

CONCLUSION

Patients with SIA have multiple markers of systemic connective tissue abnormalities. Systemic weakness of connective tissue represents a risk factor for development of SIA. Identification of these markers may help in detection of high-risk patients.

Influência de calços na orientação postural de indivíduos com escoliose idiopática

INTRODUÇÃO: A relação entre a orientação dos segmentos e os ajustes que podem ser desencadeados por calços e palmilhas em pacientes escolióticos durante a manutenção da posição ortostática é pouco conhecida. OBJETIVO: Verificar alterações estáticas e associadas com mudanças unilaterais de calços na orientação postural de indivíduos com escoliose idiopática. MATERIAIS E MÉTODOS: Grupo experimental com dez indivíduos com escoliose idiopática com curva dupla (menor 10°) e grupo controle com dez indivíduos sem escoliose (faixa etária de 13 a 24 anos). Participantes foram filmados na posição ortostática sem calço, com calço baixo (1 cm) e com calço alto (3 cm); estes foram colocados sob o pé direito e pé esquerdo dos indivíduos. Em cada condição, o participante manteve a posição estática durante 15 segundos e marcadores refletivos foram colocados em pontos anatômicos específicos. Foram calculados ângulos posturais: torácico alto; torácico médio; toracolombar e lombar e ângulos segmentares: ombro; escápula; pelve e joelho. RESULTADOS: Na condição sem calço, diferenças foram observadas entre grupos para os ângulos posturais toracolombar e lombar e para o ângulo segmentar do ombro. Com calço baixo e alto, sob o pé direito, diferença foi observada entre calços para os ângulos lombar, da pelve e do joelho. Com calço baixo e alto, sob o pé esquerdo, diferença foi observada entre grupos para o ângulo toracolombar e entre calços para os ângulos da pelve e do joelho. CONCLUSÕES: A utilização de calço promove reorientação nas regiões mais baixas da coluna e nos segmentos da pelve e do joelho. Estes resultados sugerem que nas escolioses duplas, manipulação da base de apoio modifica o alinhamento do tronco que pode provocar reorganização das estruturas e busca de um novo arranjo entre segmentos em indivíduos com escoliose idiopática.

The creation of scoliosis by scapula-to-contralateral ilium tethering procedure in bipedal rats: a kyphoscoliosis model

STUDY DESIGN

Randomized trial.

OBJECTIVE

To create a new scoliotic model.

SUMMARY OF BACKGROUND DATA

Although there were a lot of modeling techniques producing scoliosis, failed was the creation of a scoliotic animal model all characterized by the evident axial rotation of vertebrae body, the simulation of the human erect posture, and avoiding direct traumas to the spine, the spinal cord, ribs, or glands in modeling techniques.

METHODS

A total of 45 4-week-old female wistar rats were randomly divided into three groups. Group 1 underwent subcutaneous left scapula-to-contralateral ilium tethering procedure with a nonadsorbable suture, which made the spine convex toward right side, and then removed forelimbs and tails of rats to create the bipedal rats. Tethering sutures were cut at postoperative eighth week, and the spines of rats were then observed during 2 weeks. Group 2 was the same as group 1 but in which scapula-to-ipsilateral ilium tethering procedure was performed. Group 3 was the same as group 1 except that the bipedal rats were not created. All postoperative rats were fed separately in special high cages for groups 1 and 2 or in standard cages for group 3.

RESULTS

At 2 weeks after tether release, the incidence of vertebral rotation was significantly higher in group 1 than in group 2 (P = 0.004). The differences in degrees of scoliosis and kyphosis between groups at the time of initial tethering were not found to be significant (P > 0.05), whereas those at 2 weeks after tether release were significantly larger in group 1 than in group 3 (P < 0.01). There were no significant differences in postoperative first food-taking duration, body weight, spinal relative length, modeling mortality, the incidences of reoperation, and scoliosis between groups (all P > 0.05).

CONCLUSION

The scoliotic model created by scapula-to-contralateral ilium tethering procedure in bipedal rats can preferably simulate the human scoliosis.

Dynamic response of the idiopathic scoliotic spine to axial cyclic loads

STUDY DESIGN

Numerical techniques were used to study the vibration response of idiopathic scoliosis patients with single thoracic curve.

OBJECTIVE

To analyze the dynamic characteristics of the idiopathic scoliotic spine under the whole-body vibration condition. The influence of the upper body mass was also studied.

SUMMARY OF BACKGROUND DATA

The relationship between the whole-body vibration and the spinal disorders has been investigated using finite element method. However, the dynamic response features of the scoliotic spine to the vibration were poorly understood.

METHODS

The resonant frequencies of the scoliotic spine and the effects of the body weight were studied using a finite element model described previously. Modal and harmonic analysis was conducted. The amplitudes of 6 fundamental vertebral movements around the long, coronal and sagittal axis were quantified in the frequency range of 1 to 35 Hz.

RESULTS

The vibration-induced rotation amplitudes of the apex of the thoracic deformity were higher than that of the lumbar segments. The apical vertebrae had the greatest rotation amplitudes at 2 and 8 Hz, and the largest lateral translation amplitudes at 16 Hz. Vibration could cause large lateral flexion amplitudes in the apex of the thoracic deformity. The apical vertebrae had the largest side flexion amplitudes at 6 Hz. Increasing upper body mass could not change resonant frequency of vibration-induced lateral translation and rotation around the long axis of the apical vertebrae.

CONCLUSION

The scoliotic spine is more sensitive to vibration than the normal spine. For a patient with single thoracic curve, long-term whole-body vibration may do more harm to the thoracic deformity than to the lower lumbar segments. Axial cyclic loads applied to an already deformed spine may cause further rotational and scoliotic deformity. The patients with idiopathic scoliosis are more likely to suffer from vibration-induced spinal disorders than those by normal persons.

Spontaneous regression of curve in immature idiopathic scoliosis - does spinal column play a role to balance? An observation with literature review

Background

Child with mild scoliosis is always a subject of interest for most orthopaedic surgeons regarding progression. Literature described Hueter-Volkmann theory regarding disc and vertebral wedging, and muscular imbalance for the progression of adolescent idiopathic scoliosis. However, many authors reported spontaneous resolution of curves also without any reason for that and the rate of resolution reported is almost 25%. Purpose of this study was to question the role of paraspinal muscle tuning/balancing mechanism, especially in patients with idiopathic scoliosis with early mild curve, for spontaneous regression or progression as well as changing pattern of curves.

Methods

An observational study of serial radiograms in 169 idiopathic scoliosis children (with minimum follow-up one year) was carried. All children with Cobb angle < 25° and who were diagnosed for the first time were selected. As a sign of immaturity at the time of diagnosis, all children had Risser sign 0. No treatment was given to entire study group. Children were divided in three groups at final follow-up: Group A, B and C as children with regression, no change and progression of their curves, respectively. Additionally changes in the pattern of curve were also noted.

Results

Average age was 9.2 years at first visit and 10.11 years at final follow-up with an average follow-up of 21 months. 32.5% (55/169), 41.4% (70/169) and 26% (44/169) children exhibited regression, no change and progression in their curves, respectively. 46.1% of children (78/169) showed changing pattern of their curves during the follow-up visits before it settled down to final curve. Comparing final fate of curve with side of curve and number of curves it did not show any relationship (p > 0.05) in our study population.

Conclusion

Possible reason for changing patterns could be better explained by the tuning/balancing mechanism of spinal column that makes an effort to balance the spine and result into spontaneous regression or prevent further progression of curve. If this which we called as "tuning/balancing mechanism" fails, curve will ultimately progress.

Aetiology of idiopathic scoliosis: current concepts

The aetiology of the three-dimensional spinal deformity of idiopathic scoliosis (IS) is unknown. Progressive adolescent idiopathic scoliosis (AIS) that mainly affects girls is generally attributed to relative anterior spinal overgrowth from a mechanical mechanism (torsion) during the adolescent growth spurt. Established biological risk factors to AIS are growth velocity and potential residual spinal growth assessed by maturity indicators. Spine slenderness and ectomorphy in girls are thought to be risk factors for AIS. Claimed biomechanical susceptibilities are (1) a fixed lordotic area and hypokyphosis and (2) concave periapical rib overgrowth. MRI has revealed neuroanatomical abnormalities in approximately 20% of younger children with IS. A neuromuscular cause for AIS is probable but not established. Possible susceptibilities to AIS in tissues relate to muscles, ligaments, discs, skeletal proportions and asymmetries, the latter also affecting soft tissues (e.g. dermatoglyphics). AIS is generally considered to be multi-factorial in origin. The many anomalies detected, particularly left-right asymmetries, have led to spatiotemporal aetiologic concepts involving chronomics and the genome altered by nurture without the necessity for a disease process. Genetic susceptibilities defined in twins are being evaluated in family studies; polymorphisms in the oestrogen receptor gene are associated with curve severity. A neurodevelopmental concept is outlined for the aetiology of progressive AIS. This concept involves lipid peroxidation and, if substantiated, has initial therapeutic potential by dietary anti-oxidants. Growth saltations have not been evaluated in IS.

Back muscles biometry in adolescent idiopathic scoliosis

BACKGROUND CONTEXT

Many studies have been devoted to the role of back muscle activity in the development of scoliosis. While an imbalance in the electromyographic (EMG) activity has often been detected at the skin surface, very little information is available on the mechanisms by which such an imbalance could take place. To gain insight into those mechanisms, an important step could be the collection of anatomical data on the volume of the erector spinae muscle on both sides of the spine as well as on the skin and subcutaneous fat (skinfold) thickness separating those muscles from the body surface. For this purpose, the use of magnetic resonance (MR) imaging is appropriate.

PURPOSE

To collect anatomical information on the erector spinae muscles and skinfold thickness along the spinal deviations of scoliotic patients.

STUDY DESIGN

In an observational retrospective study, MR images of scoliotic patients treated in a pediatric hospital in the last 5 years were analyzed.

PATIENT SAMPLE

Images were obtained from adolescent idiopathic scoliosis patients.

METHODS

For 15 patients (Group I), three clinical acquisition protocols were used. Five investigators were asked to grade the contrast of the images obtained with each protocol. All the assessments were carried on the same monitor without any change in its settings. For the MR sequence providing the best contrast, 25 fully imaged scoliotic deviations were obtained from 17 patients (Group II). A manual segmentation with an image processing software package was done on the erector spinae muscle on both sides of the spine on each of the available images in order to determine their volume. Skinfold was also measured; first at regular intervals from C7 to L3 over the erector spinae muscle and then at sites centered over the apex of each curve.

RESULTS

For Group I, the spin echo (SE-T1) was found to provide the best contrast to identify the contour of individual muscle. With this sequence, the analysis of the fully imaged scoliotic curves (Group II) revealed that back muscle volume was found larger 14 times on the concave side and 11 times on the convex one. When the length of each curve was normalized and then divided into three equal regions, muscle volume was larger 11 times at the apex (6 times on concave side), 7 times above and 7 times below (4 times on the concave side for both positions). From C7 to L3, the mean skinfold thickness of each patient ranged from 7.3 mm to 16.3 mm. On average, this thickness was <10 mm between T3 and T12 but became larger at L3 level. At the apex of each scoliotic deviation, skinfold thickness was always larger on the concave side, and the difference decreased progressively as the distance from the apex increased.

CONCLUSION

A larger back muscle volume in adolescent idiopathic scoliosis patients was slightly more frequent on the concave than on the convex side. The differences were more frequent at the apex of the curve. Skinfold thickness was always greater on the concave side at the apex region.

Biomechanical spinal growth modulation and progressive adolescent scoliosis--a test of the 'vicious cycle' pathogenetic hypothesis: summary of an electronic focus group debate of the IBSE

There is no generally accepted scientific theory for the causes of adolescent idiopathic scoliosis (AIS). As part of its mission to widen understanding of scoliosis etiology, the International Federated Body on Scoliosis Etiology (IBSE) introduced the electronic focus group (EFG) as a means of increasing debate on knowledge of important topics. This has been designated as an on-line Delphi discussion. The text for this debate was written by Dr Ian A Stokes. It evaluates the hypothesis that in progressive scoliosis vertebral body wedging during adolescent growth results from asymmetric muscular loading in a "vicious cycle" (vicious cycle hypothesis of pathogenesis) by affecting vertebral body growth plates (endplate physes). A frontal plane mathematical simulation tested whether the calculated loading asymmetry created by muscles in a scoliotic spine could explain the observed rate of scoliosis increase by measuring the vertebral growth modulation by altered compression. The model deals only with vertebral (not disc) wedging. It assumes that a pre-existing scoliosis curve initiates the mechanically-modulated alteration of vertebral body growth that in turn causes worsening of the scoliosis, while everything else is anatomically and physiologically 'normal' The results provide quantitative data consistent with the vicious cycle hypothesis. Dr Stokes' biomechanical research engenders controversy. A new speculative concept is proposed of vertebral symphyseal dysplasia with implications for Dr Stokes' research and the etiology of AIS. What is not controversial is the need to test this hypothesis using additional factors in his current model and in three-dimensional quantitative models that incorporate intervertebral discs and simulate thoracic as well as lumbar scoliosis. The growth modulation process in the vertebral body can be viewed as one type of the biologic phenomenon of mechanotransduction. In certain connective tissues this involves the effects of mechanical strain on chondrocytic metabolism a possible target for novel therapeutic intervention.

POSTMASTECTOMY SEROUS DRAINAGE AND SEROMA: PROBABLE PATHOGENESIS AND PREVENTION

Seromas and prolonged, excessive drainage of serous fluid constitute the most common complications of mastectomy for breast carcinoma. The pathogenesis of this drainage problem is analysed from a pathological perspective and encompasses the role of biomechanical stresses involved in healing. Closed suction drainage delays healing and contributes to the accumulation of serum fluid in the wound. Suction of air into the patient's wound potentiates chronic drainage and seroma formation, adding to patient discomfort and increased risk of infection. The principle of primary union of the wound should be reinstated in mastectomies and to this end relevant changes in the surgical and postoperative management are proposed.

Regression of juvenile idiopathic scoliosis

For a young scoliotic boy the customary "wait and watch" management program for rapidly progressive juvenile idiopathic scoliosis was considered unsatisfactory in view of the poor prognosis. The management program devised was based on the congenital postural induction concept of scoliosis with progression accruing from mechanically induced bioengineering fatigue, cumulative molecular scissions, laxity of ligaments, and secondary bone deformation. A coexisting pelvic tilt with restricted movement of the hip and shoulder joints was overlooked initially. Possibly induced simultaneously with the scoliosis, it is considered a contributory factor in scoliosis progression and requires early diagnosis and correction. The rapid improvement in this child's spinal status achieved by physiological traction and specifically designed exercises was such that as a preventive measure the technique warrants further clinical assessment on young scoliotics.