BACKGROUND:The asymmetrical biomechanical environment of adolescent idiopathic scoliosis can lead to further wedge deformation of the vertebral body,which may affect cardiopulmonary function and compress nerves in severe cases.Adolescent idiopathic scoliosis with different degrees of scoliosis should be treated with exercise,bracing,and surgery.However,the mechanical mechanism of selecting an orthopedic approach remains unclear due to the individual variability of patients.OBJECTIVE:To investigate the biomechanical mechanism of different orthopedic modalities for the treatment of adolescent idiopathic scoliosis to provide a basis for clinical selection of treatment modalities based on the spine model of adolescent idiopathic scoliosis patients.METHODS:Based on the CT images of an adolescent idiopathic scoliosis patient,a scoliosis model(C7-L5)was reconstructed in Mimics software in three dimensions,and lateral thrust force was applied at the T8/T9 thorax and vertical distraction force was applied over the C7 vertebra with the magnitude of 20,40,60,80,100,and 120 N.The intervertebral disc stress and vertebral displacement in concave and convex sides,and Cobb angle of the spine were analyzed under two orthopedic modalities.RESULTS AND CONCLUSION:(1)With lateral thrust,there was no significant change in the C7T1-T7T8 intervertebral disc.The concave and convex stress of T7T8-L4L5 segment decreased first and then increased with the increase of lateral thrust force.The correction effect of lateral thrust on the segment near T8T9 was obvious and weakened with the extension of the segment to the cephalic and caudal ends.At 120 N of lateral thrust,the thoracic Cobb angle changed from 53.2° to 32.5° and the lumbar Cobb angle changed from 50.2° to 43.9°.(2)With the vertical distraction,the thoracic intervertebral disc stresses first decreased and then increased,and all the lumbar disc stresses decreased.The C7 displacement was the most obvious,and the correction effect gradually diminished with the segment extended to the caudal end.At a vertical distraction force of 120 N,the thoracic Cobb angle changed from 53.2° to 39.4° and the lumbar Cobb angle changed from 50.2° to 47.6°.(3)It is concluded that both orthopedic modalities provide improvement in the degree of scoliosis,with the thoracic correction being greater than the lumbar correction.Also,the asymmetric stress distribution on the concave and convex sides is improved,which contributes to normal bone growth.A vertical distraction approach is appropriate for larger Cobb angles,and a lateral thrust approach is appropriate for smaller Cobb angles.The results of this study help to understand the mechanism of spinal orthosis and provide a theoretical basis for the choice of orthopedic approach.

Objective A scoping review of studies on pulmonary prehabilitation in cardiac surgery patients was conducted to provide evidence support for the construction of a preoperative pulmonary rehabilitation program for cardiac surgery patients that suitable for China's national conditions.Methods In accordance with the scope review's research methodologies,databases including PubMed,Embase,Web of Science,CINAHL,CNKI and Wanfang were searched by the computer for relevant studies.The deadline for retrieval is from the establishment of databases to June,2024.The included literature was systematically analyzed.Results 26 articles were finally included.Among them,4 were quasi-experiment studies,while the other 22 were randomized controlled trials.Forms of the intervention included comprehensive breathing exercises,inspiratory muscle training,positive expiratory pressure,incentive spirometer training and balloon blowing training.The intervention initiation ranged from 10 weeks to 1 day preoperatively;the outcome measures included postoperative pulmonary complications,lung function metrics,the 6-Minute Walk Test,duration of mechanical ventilation,length of hospital stay,patient-reported outcomes and so on.Conclusion There remains a deficiency in standardized protocols for preoperative pulmonary rehabilitation training among patients undergoing cardiac surgery.High-quality studies should be conducted,and intervention strategies for pulmonary prehabilitation in cardiac surgery patients should be optimized and a unified evaluation standard system should be established.

Objective To compare the value of standard deviation(SD)method and root mean square(RMS)method for measuring signal-to-noise ratio(SNR)of MRI of American College of Radiology(ACR)phantom based on phased array coils.Methods ACR phantom was scanned with head coil(Head),abdominal coil(Anterior),dual piece flexible coil(Flex L)and abdominal coil+flexible coil(Anterior+Flex L)each for 6 times,respectively,with sequences of axial T 1W-spin echo(SE)and T2W-SE.And the scanning schemes were divided into 8 groups based on 4 types of coils and 2 sequences.SNR of 8 groups were measured with standard deviation method and root mean square method,respectively,and the differences between the above 2 methods were observed.Results For T1W-SE sequence,SNRsD of MRI based on Head,Anterior,Flex L and Anterior+Flex L was 1.25±0.07,0.56±0.02,1.15±0.10 and 1.04±0.11,respectively,while SNRRMs was 1.10±0.07,0.58±0.03,1.01±0.13 and 1.31±0.15,respectively.For T2W-SE sequence,SNRsD was 1.40±0.08,0.48±0.02,1.04±0.07 and 1.08±0.06,respectively,while SNRRMs was 1.29±0.09,0.53±0.03,0.84±0.08 and 1.35±0.12,respectively.Compared pairwise,significant difference of SNRsD was found in 9 pairs(all P＜0.05),while of SNRRMs was detected in 10 pairs(all P＜0.05).Conclusion Compared with standard deviation method,root mean square method was more suitable for measuring SNR of MRI of ACR phantom based on phased array coils.

BACKGROUND:Adolescent lumbar disc herniation is the main cause of low back pain in adolescents. At present,most of them are treated by conservativetreatment. When long-term non-surgical treatment attempts,surgery may be necessary to prevent further injury when the patient's symptoms are notsufficiently relieved or when the patient has symptoms of single nerve paralysis or compression of the cauda equina,it is very important to choose a suitable interbody fusion device for the surgical treatment of the patients.OBJECTIVE:To explore the effects of minimally invasive interbody fusion with different heights on lumbar biomechanics in patients with adolescent lumbar disc herniation.METHODS:CT scans of a 17-year-old male patient with adolescent lumbar disc herniation (L4-5 segment herniation) were collected. After the three-dimensional reconstruction of MIMICS,the interbody fusion device equal to and 3 mm higher than the intervertebral space was selected for analysis,so two expandablemixed material interbody fusion devices were designed and reconstructed. Fusion device L:11 mm high front,9 mm high posterior,9 mm wide,28 mmlong,and fusion device H:14 mm high front,11 mm high posterior,11 mm wide,28 mm long and the lumbar fusion device was modeled. The fusion deviceand lumbar spine model were optimized,inversely modeled,and then imported into ABAQUS,and finally the 3D model of lumbar fusion was obtained.The physiological activities of the human body were simulated,such as lumbar extension,forward bending,right bending,and left bending,to obtain thecorresponding stress contours. The biomechanical characteristics of the L4-5 vertebra under seven different working conditions were observed.RESULTS AND CONCLUSION:(1) The maximum stress of the two kinds of fuses was in the condition of forward bending and backward extension,the stress value of H fuses was (18.27±3.80) Mpa and (15.02±3.24) Mpa;the stress value of L fuses was (9.16±0.05) Mpa and (9.17±1.83) Mpa. The stress values of the end plate of the H-fusion in the extension station were (19.11±4.03) Mpa and (16.32±3.72) Mpa respectively. The stress values of the L-fusion end plate were (9.13±0.01) Mpa and (4.92±1.01) Mpa respectively. (2) The stress of H-type fusing end plate was higher than that of L-type fusing end plate except for L-5 end plate at neutral position (P<0.05). (3) Choosing an interbody fusion device with a height of more than 3 mm in the same intervertebral space has a more stable biomechanics.

BACKGROUND:Adolescent lumbar disc herniation is the main cause of low back pain in adolescents. At present,most of them are treated by conservativetreatment. When long-term non-surgical treatment attempts,surgery may be necessary to prevent further injury when the patient's symptoms are notsufficiently relieved or when the patient has symptoms of single nerve paralysis or compression of the cauda equina,it is very important to choose a suitable interbody fusion device for the surgical treatment of the patients.OBJECTIVE:To explore the effects of minimally invasive interbody fusion with different heights on lumbar biomechanics in patients with adolescent lumbar disc herniation.METHODS:CT scans of a 17-year-old male patient with adolescent lumbar disc herniation (L4-5 segment herniation) were collected. After the three-dimensional reconstruction of MIMICS,the interbody fusion device equal to and 3 mm higher than the intervertebral space was selected for analysis,so two expandablemixed material interbody fusion devices were designed and reconstructed. Fusion device L:11 mm high front,9 mm high posterior,9 mm wide,28 mmlong,and fusion device H:14 mm high front,11 mm high posterior,11 mm wide,28 mm long and the lumbar fusion device was modeled. The fusion deviceand lumbar spine model were optimized,inversely modeled,and then imported into ABAQUS,and finally the 3D model of lumbar fusion was obtained.The physiological activities of the human body were simulated,such as lumbar extension,forward bending,right bending,and left bending,to obtain thecorresponding stress contours. The biomechanical characteristics of the L4-5 vertebra under seven different working conditions were observed.RESULTS AND CONCLUSION:(1) The maximum stress of the two kinds of fuses was in the condition of forward bending and backward extension,the stress value of H fuses was (18.27±3.80) Mpa and (15.02±3.24) Mpa;the stress value of L fuses was (9.16±0.05) Mpa and (9.17±1.83) Mpa. The stress values of the end plate of the H-fusion in the extension station were (19.11±4.03) Mpa and (16.32±3.72) Mpa respectively. The stress values of the L-fusion end plate were (9.13±0.01) Mpa and (4.92±1.01) Mpa respectively. (2) The stress of H-type fusing end plate was higher than that of L-type fusing end plate except for L-5 end plate at neutral position (P<0.05). (3) Choosing an interbody fusion device with a height of more than 3 mm in the same intervertebral space has a more stable biomechanics.

BACKGROUND:The asymmetrical biomechanical environment of adolescent idiopathic scoliosis can lead to further wedge deformation of the vertebral body,which may affect cardiopulmonary function and compress nerves in severe cases.Adolescent idiopathic scoliosis with different degrees of scoliosis should be treated with exercise,bracing,and surgery.However,the mechanical mechanism of selecting an orthopedic approach remains unclear due to the individual variability of patients.OBJECTIVE:To investigate the biomechanical mechanism of different orthopedic modalities for the treatment of adolescent idiopathic scoliosis to provide a basis for clinical selection of treatment modalities based on the spine model of adolescent idiopathic scoliosis patients.METHODS:Based on the CT images of an adolescent idiopathic scoliosis patient,a scoliosis model(C7-L5)was reconstructed in Mimics software in three dimensions,and lateral thrust force was applied at the T8/T9 thorax and vertical distraction force was applied over the C7 vertebra with the magnitude of 20,40,60,80,100,and 120 N.The intervertebral disc stress and vertebral displacement in concave and convex sides,and Cobb angle of the spine were analyzed under two orthopedic modalities.RESULTS AND CONCLUSION:(1)With lateral thrust,there was no significant change in the C7T1-T7T8 intervertebral disc.The concave and convex stress of T7T8-L4L5 segment decreased first and then increased with the increase of lateral thrust force.The correction effect of lateral thrust on the segment near T8T9 was obvious and weakened with the extension of the segment to the cephalic and caudal ends.At 120 N of lateral thrust,the thoracic Cobb angle changed from 53.2° to 32.5° and the lumbar Cobb angle changed from 50.2° to 43.9°.(2)With the vertical distraction,the thoracic intervertebral disc stresses first decreased and then increased,and all the lumbar disc stresses decreased.The C7 displacement was the most obvious,and the correction effect gradually diminished with the segment extended to the caudal end.At a vertical distraction force of 120 N,the thoracic Cobb angle changed from 53.2° to 39.4° and the lumbar Cobb angle changed from 50.2° to 47.6°.(3)It is concluded that both orthopedic modalities provide improvement in the degree of scoliosis,with the thoracic correction being greater than the lumbar correction.Also,the asymmetric stress distribution on the concave and convex sides is improved,which contributes to normal bone growth.A vertical distraction approach is appropriate for larger Cobb angles,and a lateral thrust approach is appropriate for smaller Cobb angles.The results of this study help to understand the mechanism of spinal orthosis and provide a theoretical basis for the choice of orthopedic approach.

Objective A scoping review of studies on pulmonary prehabilitation in cardiac surgery patients was conducted to provide evidence support for the construction of a preoperative pulmonary rehabilitation program for cardiac surgery patients that suitable for China's national conditions.Methods In accordance with the scope review's research methodologies,databases including PubMed,Embase,Web of Science,CINAHL,CNKI and Wanfang were searched by the computer for relevant studies.The deadline for retrieval is from the establishment of databases to June,2024.The included literature was systematically analyzed.Results 26 articles were finally included.Among them,4 were quasi-experiment studies,while the other 22 were randomized controlled trials.Forms of the intervention included comprehensive breathing exercises,inspiratory muscle training,positive expiratory pressure,incentive spirometer training and balloon blowing training.The intervention initiation ranged from 10 weeks to 1 day preoperatively;the outcome measures included postoperative pulmonary complications,lung function metrics,the 6-Minute Walk Test,duration of mechanical ventilation,length of hospital stay,patient-reported outcomes and so on.Conclusion There remains a deficiency in standardized protocols for preoperative pulmonary rehabilitation training among patients undergoing cardiac surgery.High-quality studies should be conducted,and intervention strategies for pulmonary prehabilitation in cardiac surgery patients should be optimized and a unified evaluation standard system should be established.

Objective To compare the value of standard deviation(SD)method and root mean square(RMS)method for measuring signal-to-noise ratio(SNR)of MRI of American College of Radiology(ACR)phantom based on phased array coils.Methods ACR phantom was scanned with head coil(Head),abdominal coil(Anterior),dual piece flexible coil(Flex L)and abdominal coil+flexible coil(Anterior+Flex L)each for 6 times,respectively,with sequences of axial T 1W-spin echo(SE)and T2W-SE.And the scanning schemes were divided into 8 groups based on 4 types of coils and 2 sequences.SNR of 8 groups were measured with standard deviation method and root mean square method,respectively,and the differences between the above 2 methods were observed.Results For T1W-SE sequence,SNRsD of MRI based on Head,Anterior,Flex L and Anterior+Flex L was 1.25±0.07,0.56±0.02,1.15±0.10 and 1.04±0.11,respectively,while SNRRMs was 1.10±0.07,0.58±0.03,1.01±0.13 and 1.31±0.15,respectively.For T2W-SE sequence,SNRsD was 1.40±0.08,0.48±0.02,1.04±0.07 and 1.08±0.06,respectively,while SNRRMs was 1.29±0.09,0.53±0.03,0.84±0.08 and 1.35±0.12,respectively.Compared pairwise,significant difference of SNRsD was found in 9 pairs(all P＜0.05),while of SNRRMs was detected in 10 pairs(all P＜0.05).Conclusion Compared with standard deviation method,root mean square method was more suitable for measuring SNR of MRI of ACR phantom based on phased array coils.

BACKGROUND:Ankylosing spondylitis is a chronic inflammatory disease with chronic rheumatic immunity.Soft tissue ossification and fusion and spinal stiffness can cause biomechanical changes. OBJECTIVE:To reconstruct the lumbar-sacral intervertebral disc in ankylosing spondylitis patients with lumbar kyphosis by finite element analysis,and to study the range of motion of each segment of T11-S1 and the biomechanical characteristics of annulus fibrosus and nucleus pulposus. METHODS:The imaging data were obtained from an ankylosing spondylitis patient with lumbar kyphosis.The original CT image data of continuously scanned spine were imported into Mimics 21.0 in DICOM format,and T11-S1 was reconstructed respectively.The established model was imported into 3-Matic software in the format of"Stl"to reconstruct the intervertebral disc,and the fibrous intervertebral disc model was obtained.The improved model was further imported into Hypermesh software,and the vertebra,nucleus pulposus,annulus fibrosus and ligament were mesh-divided.After the material properties were given,the model was imported into ABAQUS software to observe the range of motion of each vertebral body in seven different working conditions of T11-S1,and analyze the biomechanical characteristics of each segment of annulus fibrosus and nucleus pulposus. RESULTS AND CONCLUSION:(1)The range of motion of L1 vertebrae was higher than that of other vertebrae under six different working conditions:extension,forward flexion,rotation(left and right),and lateral flexion(left and right).The maximum range of motion was 2.18° during L1 vertebral flexion,and the minimum range of motion was 0.12° during L5 vertebral extension.(2)The annular fiber flexion at L2-L3 segments was greater than the extension(P<0.05),and the annular fiber flexion at L3-L4 and L4-L5 segments was less than the extension(P<0.05).The left rotation of L1-L2 annular fibers was greater than the right rotation(P<0.05).The left flexion of the annulus was greater than the right flexion in L1-L2,L2-L3,L3-L4,L4-L5 and L5-S1 segments(P<0.05).(3)The nucleus pulposus stresses of T11-L12,L1-L2,L2-L3,L3-L4 and L4-L5 segments in forward flexion were greater than in extension(P<0.05).The left rotation of T12-L1 and L3-L4 segments was smaller than the right rotation(P<0.05),and that of T11-T12,L1-L2,and L2-L3 segments was larger than the right rotation(P<0.05).The left flexion was larger than the right flexion in the T11-S1 segment.(4)It is concluded that in ankylosing spondylitis patients with lumbar kyphosis,the minimum range of motion of the vertebral body is located at the L5 vertebral body in extension.To prevent fractures,it is recommended to avoid exercise in the extension position.During the onset of lumbar kyphosis in patients with ankylosing spondylitis,the maximum stress of the annulus fibrosus and nucleus pulposus is located in the L1-L2 segment,which is fixed and will not alter with the change of body position.The late surgical treatment and correction of deformity should focus on releasing the pressure of the annulus fibrosus and nucleus pulposus in this segment to avoid the rupture of the annulus fibrosus and the injury of the nucleus pulposus.

BACKGROUND:Ankylosing spondylitis is a progressive inflammation of spinal stiffness deformity caused by tissue ossification and fibrosis.The posture of ankylosing spondylitis patients is abnormal and their activities are limited that minor injuries can lead to thoracolumbar fractures.Traditional medical image observation limits doctors'preoperative decision planning and postoperative disease prevention for ankylosing spondylitis treatment. OBJECTIVE:Based on the spinal model of ankylosing spondylitis patients before and after posterior spinal cancellous ossification osteotomy("Y"osteotomy for short),to explore the biomechanical changes of"Y"osteotomy and fixation in the treatment of ankylosing spondylitis. METHODS:Based on the preoperative and postoperative CT images of an ankylosing spondylitis patient who went to the Second Affiliated Hospital of Inner Mongolia Medical University,a three-dimensional spine model(T11-S1)before and after"Y"osteotomy(L3 osteotomy)was reconstructed in Mimics 19.0 software.A 7.5 Nm torque was applied to the top of T11 vertebral body to simulate the movement of the spine under six conditions:flexion,extension,left bending,right bending,left rotation and right rotation.Finally,the range of motion of each vertebral body,the stress of each intervertebral disc,and the stress of the screw rod system were simulated. RESULTS AND CONCLUSION:(1)After"Y"type osteotomy and posterior fixation,the range of motion of all vertebrae in the spine decreased,and the loss rate of upper vertebrae was large(L1:77.95%).(2)The maximum stress of the spinal intervertebral disc before operation occurred at the L1-L2 segment(0.55 MPa),and the maximum stress of the spinal intervertebral disc after operation occurred at the T11-T12 segment(0.50 MPa),and the stress of intervertebral disc below T12 was far less than that before operation.(3)The maximum stress of the screw rod system(166.67 MPa)occurred in the upper and middle segments of the rod body and the root of the pedicle screw.(4)In conclusion,the"Y"type posterior fixation operation enhances the stability of the spine and reduces the range of motion of the spine.The vertebral body decompression of the fixed segment is great and the stress-shielding phenomenon of the lower vertebral body is significant.The stiffness of the rod body and the stress concentration area of the pedicle screw should be strengthened to avoid the fracture of the rod caused by stress fatigue.