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Objective To evaluate the efficacy of additive manufacturing scoliosis orthosis, by simulation on interaction of the bone, trunk and orthosis using finite element method. Methods Combined with CT data of the patients, three-dimensional (3D) scanning model of the trunk and full length X-ray of the spine, the bone-trunk-orthosis finite element model was established and proved to be effective. The change and development trend of Cobb angle of the main thoracic scoliosis was calculated under different boundary and load conditions. Results The treatment effect of the additive manufacturing scoliosis orthosis was good. With the increase of orthotic preload, the improvement of Cobb angle and pelvic tilt was more obvious. The Cobb angle was expected to decrease by 6.18° after application of 70 N preload to the orthosis for 6 months. In the case of increasing system stiffness, Cobb angle improvement was not obvious and became even worse. Conclusions Additive manufacturing scoliosis orthosis is effective for treating adolescents with immature bones, while for patients with mature or degenerative bones, its treatment effect is poor.
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Objective To establish the three-dimensional (3D) finite element (FE) model of thoracolumbosacral T1-S spine based on the computed tomography (CT) images of patients with scoliosis and study its dynamic characteristics. Methods The established scoliotic model was validated by axial compression and shear loading, and the predicted responses were in good agreement with the experimental data. The modal and harmonic analyses were performed using the ABAQUS software, and during the harmonic analysis, the dynamic response of the model was collected at frequencies 5 Hz and 10 Hz. Results From the modal analysis, the first fourth-order modal was extracted. The first- and second-order resonant frequencies of the model were 1.097 Hz and 1.384 Hz, respectively, and the vibration mode was longitudinal bending and lateral bending, respectively. The distribution of the second- and third-order modal resonant frequencies were 5.688 Hz and 28.090 Hz, and the vibration mode was vertical vibration and twisting around the long axis, respectively. The peak amplitude in the harmonic analysis appeared near the modal frequencies, and the average amplitude of vertebral body of the lateral convex segment was larger than that of other segments of the scoliotic spine. Under the vibration frequencies of 5 Hz and 10 Hz, the stress inhomogeneously concentrated on the concave and convex sides of the segments of the vertebral deformity as well as on the intervertebral disc. Conclusions The segments of the spinal deformity in patients with scoliosis were the weak links of their spines and more vulnerable to damage in a vibrating environment. Patients with scoliosis should avoid a vibrating environment, particularly in a sensitive frequency range. The research outcomes provide methodological assistance and mechanical analysis references for the protection, rehabilitation treatment, and clinical pathological studies of patients with scoliosis.
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STUDY DESIGN: A retrospective study. OBJECTIVES: To evaluate the sagittal alignment of cervical spine in AIS. SUMMARY OF LITERATURE REVIEW: Little has been known about the sagittal curve patterns of cervical spine in AIS patients. MATERIALS AND METHODS: One-hundred-thirty-three AIS patients were checked by scanographs and followed up for more than 2 years were divided into cervical kyphosis (> or =+5degrees), lordosis (< or =-5degrees) and straight (-4degrees~+4degrees) groups according to the sagittal curves of cervical spine (C2~C7). Each group was evaluated for thoracic kyphosis, lumbar lordosis, sagittal balance and Cobb's angle on coronal plane. Of the patients, 49 were treated by braces, 84 were surgically corrected (rod derotation in 52, direct vertebral rotation (DVR) in 32). RESULTS: At the initial radiographs, cervical kyphosis was found in 97, lordosis in 23 and straight in 13 patients. In the kyphosis group, cervical kyphosis showed typical patterns of angular kyphosis. Thoracic and upper T-kyphosis (T1~T5) were lower than those in the cervical lordosis group (p=0.000, 0.001, respectively.) Other factors showed no significant differences between the groups. Patients treated by conservative management or by rod derotation had no significant differences in cervical kyphosis during the follow-up periods, though the thoracic hypokyphosis was surgically corrected. On the contrary, patients who were treated by DVR restored cervical lordosis (14/32=43.8%) from initial state showed significant differences in both conservative and rod derotation groups (p=0.008, 0.002, respectively). CONCLUSIONS: Cervical kyphosis in AIS was a compensatory curve correlated with both thoracic hypokyphosis and rotational deformity. Rotational corrections should be considered during the surgical treatment.
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Adolescent , Animals , Humans , Braces , Congenital Abnormalities , Follow-Up Studies , Kyphosis , Lordosis , Retrospective Studies , Scoliosis , SpineABSTRACT
[Objective]To compare spontaneous correction of the unfused thoracic curves after selective anterior versus posterior fusion in Lenke5 adolescent idiopathic scoliosis(AIS). [Method]A total of 72 Lenke5 AIS patients were rescruited from May 1997 to October 2005.Out of them,40 received selective anterior fusion(group A) and 32 received selective posterior fusion(group B).All had a minimum of 2-year follow-up.[Result] No complication were found in both groups at the latest follow-up.The thoracic curve was corrected from 30? to 16? for group A,33? to 18? for group B.Both groups had a better spontaneous correction of the unfused thoracic curves.The correction rate had no significant difference between groups.However,the thoracic curve was increased in four patients(2 in each group;group C),which resulted in trunk imbalance.The thoracolumbar/lumbar thoracic(TL/L:T) Cobb's ratio averaged 1.09 in the four patients whereas 1.59 in other 68 patients(group D).The flexibility of the thoracic curve had significant difference in group C and D(34.2% vs 57.3%).[Conclusion]Both of the surgical treatments can get a better spontaneous correction of the unfused thoracic curves.It is important to evaluate the.thoracolumbar/lumbar–thoracic(TL/L:T) Cobb's ratio and the flexibility of the thoracic curve before selective fusion.
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[Objective]To evaluate the role of three radiographic ways in patients undergoing spinal three-dimensional correction and fusion for adolescent idiopathic scoliosis.[Method]Sixty-three cases of adolescent idiopathic scoliosis(AIS)with 79 structural curves were studied.Preoperative X-ray of standing,gravity-suspendig traction,supine bending and fulcrum bending were compared with postoperative standing X-ray one week after surgery,Cobbs angle of all X-ray were measured and statistical significance was evaluated.[Result]In structural thoracic group and lumbar group the mean Cobbs angle were 40?and 21?in gravity-suspendig traction X-ray,41?and 23?in supine bending X-ray,35?and 19?in fulcrum bending X-ray,36?and 18?in postoperative standing X-ray respectively.In severe group and moderate group the mean Cobbs angle were 52?and 23?in gravity-suspendig traction X-ray,53?and 24?in supine bending X-ray,47?and 20?in fulcrum bending X-ray,44?and 19?in postoperative standing X-ray respectively.In rigid group and flexible group the mean Cobbs angle were 51?and 22?in gravity-suspendig traction X-ray,52?and 22?in supine bending X-ray,48?and 18?in fulcrum bending X-ray,45?and 17?in postoperative standing X-ray respectively.In anterior approach group and posterior approach group the mean Cobbs angle were 47?and 15?in gravity-suspendig traction X-ray,49?and 16?in supine bending X-ray,43?and 11?in fulcrum bending X-ray,42?and 10?in postoperative standing X-ray respectively.All above Cobbs angle were mean numerical value,the mean follow-up period was 1.5 years(range:1~3 years).[Conclusion]The fulcrum bending X-ray are more predicting of correctability of AIS patients than the gravity-suspendig traction and supine bending X-ray.It can provide reference for chosing anterior or posterior approach and chosing fusion levels.