| BackgroundScoliosis is the main type of human spinal deformity.According to the etiological classification,it can be divided into idiopathic scoliosis,congenital scoliosis,degenerative scoliosis,neuromuscular scoliosis,traumatic scoliosis,etc.According to age,it can also be divided into early on-set scoliosis,adolescent scoliosis and adult scoliosis.Among them,adolescent idiopathic scoliosis(AIS)is the most common.AIS is a complex three-dimensional deformity,including coronal scoliosis,sagittal curve abnormality(kyphosis,flat back,lordosis,i.e.non-physiological curvature),axial vertebral rotation deformity.At first,people’s understanding of scoliosis was limited to the coronal scoliosis deformity.The focus of treatment was how to correct scoliosis deformity.With the continuous research and understanding of scoliosis deformity,sagittal anomalies and correction became the second focus.However,in clinical practice,after better correction of scoliosis and sagittal anomalies,patients still have coronal or sagittal imbalance of trunk,and abnormal curvature of the junction area of secondary upper and lowest instrumented vertebra(UIV,LIV)after operation.It is found that the axial vertebral rotation is a very important reason.Since then,the cognition of scoliosis has changed from a single two-dimensional structure to a three-dimensional structure.The research of axial vertebral rotation,the invention and application of de-rotation technology and special surgical instruments fully demonstrate that scoliosis axis deformity has become an important focus of clinical and scientific research.Clinical evaluation of the degree of vertebral rotation in AIS patients through coronal X-ray films and Nash-Moe vertebral rotation grading system indirectly evaluates the rotation of the vertebral axis.Although it is simple and easy to use,the accuracy is very low,and it has little guiding significance for clinical application,especially in surgery.With the application of CT or MRI technology,it is easy to obtain the axial images of the spine and observe the rotation of the vertebral body intuitively on the axial plane.It is of great value to understand the three-dimensional deformity structure,especially to guide the treatment of vertebral body de-rotation during operation.In addition,CT or MRI can be used to understand the anatomical relationship between the vertebral body and its surrounding important structures,especially the adjacent relationship between the thoracic vertebral body and the descending aorta.Especially in today when pedicle screw has been widely used in scoliosis correction,it is particularly important and prominent,because the poor placement of metal screw and other reasons can directly lead to aortic injury,once it occurs,the consequences are extremely dangerous.With the development of science and technology,O-arm imaging system is gradually applied in clinical surgery.Its main function is to guide pedicle screw through its convenient mobility,which can move conveniently in the operating room.It can scan the spine at 360 degrees and form three-dimensional structure images of the spine.It can provide images of the coronal,sagittal and axial planes of the spine,and guide to place pedicle screw with the use of navigation system safely.Because of the use of preoperative CT or MRI images,supine images are provided without special circumstances.Using the O-arm imaging system,we can get the images of the patients in the actual position during the operation.It has great advantages and practical clinical application value in studying the rotation of the vertebral axis and the relationship between the vertebral axis and the aorta.Few studies of this kind have been reported in the literature.ObjectiveAxial plane images of the vertebral body were obtained in the supine position by MRI before operation,the prone position and the left lateral position by O-arm imaging system in the intraoperation.1.To investigate and analyze the effect of three different position(preoperative,posterior and anterior)on vertebral rotation in patients with AIS and its clinical application.2.To investigate and analyze the relationship between the main thoracic apex and the aorta in three different positions(preoperative,posterior and anterior)in patients with AIS and its clinical application.Methods1.A retrospective analysis was made of the vertebral axial images obtained by preoperative MRI(supine position)and intraoperative O-arm imaging system(prone position and left position)in AIS patients undergoing posterior incision and internal fixation and anterior thoracoscopic surgery.The Cobb angle,thoracic kyphosis Cobb angle,apical vertebrae rotation(AVR),upper end vertebra rotation(UEVR),lower end vertebra rotation(LEVR),adjacent vertebrae above UEV rotation(AVAUEVR),adjacent vertebrae below LEV rotation(AVBLEVR).Specify that rotation to the right of the vertebra is marked as negative and rotation to the left as positive.Paired t-test and independent sample t-test were used to analyze the data,and the rotation differences of different positions were compared.Pearson correlation analysis was used to analyze the correlation of vertebral rotation in three positions.2.A retrospective analysis was made on the axial images of vertebral body obtained by preoperative MRI(supine position)and O-arm imaging system(prone position and left position)in patients with AIS who underwent posterior incision and internal fixation and anterior thoracoscopic surgery.Cobb angle,Cobb angle of thoracic kyphosis and(1)apical vertebral rotation(AVR);(2)Distance from the aorta to the vertebral body(line a);(3)Distance from the point of left screw to aorta(line b);(4)Distance from the aorta to the spinal canal(line c);(5)Vertical distanc from the line acoss the left screw point to aorta(line d);(6)δ(Aorta-vertebral angle,AVA);(7)ψ(the angle between the left pedicle screw placement point and the medial tangent of the aorta and the axis of the vertebral body);(8)θ(the angle between the line passing through the left pedicle screw placement point and the central point of aorta and the parallel line of the axis of the vertebral body).Paired sample t-test and independent sample t-test were used to compare the position changes of the apical vertebrae and aorta in three positions.Pearson correlation analysis was used to analyze the relationship between the apical vertebrae and aorta in three positions.Results1.In the study of vertebral rotation,43 patients were included in this study.The Cobb angle of the main thoracic curve was 46.5-80.7 degrees in 21 patients in the posterior surgery group,with an average of 58.99±11.11 degrees,and the kyphosis angle of T5-T12 was 0-52.1 degrees,with an average of 19.08 ±12.39 degrees.The Cobb angle of the main thoracic curve was 35.1-75 degrees in 22 patients in the anterior surgery group,with an average of 46.97 ±8.58 degrees,and the kyphosis angle of T5-T12 was 0-35.2 degrees,with an average of 12.12 ±11.5 degrees.The degree of AVR in supine position was less than that in prone position,with an average difference of 3.14 degrees and a standard deviation of 1.43 degrees,P=0.015.The difference was statistically significant(P<0.05).UEVR and AVAUEVR in supine position were less than those in prone position,with the average difference being 1.98 and 0.83 degrees,respectively.However,LEVR and AVBLEVR in supine position were higher than those in prone position,with the average difference being 1.07 and 1.86 degrees,but about UEVR,LEVR,AVAVR,AUEVR,AVAVR,and AVAVR,there was no significant difference in degree between the two positions(P > 0.05).At the same time,it can be found that the rotation direction of AVAUEVR has changed from the right rotation of the upper vertebral body to the left rotation,and the rotation direction of AVBLEVR has also changed from the right rotation of the lower vertebral body to the left rotation.The vertebral rotation in the supine position before operation in the posterior approach group was compared with that in the anterior approach group during operation in the left lateral position(right thoracic approach).It was found that the rotation of the AVR in the supine position before operation in the posterior approach group was-16.56±4.38 degrees.The rotation of AVR in the left lateral position in the anterior approach group decreased significantly,with an average difference of-12.52 ±3.58 degrees,an average difference of 4.04,with an average decrease of the standard deviation of 0.8,P = 0.002,the difference was significant(P < 0.05),the difference was significant.The rotation of the upper and lower end vertebrae in the left position was lower than that in the supine position.The average difference was 0.64 degree and 2.96 degree,respectively,and the standard deviation was 1.69 degree and 1.73 degree.However,there was no significant difference in vertebral rotation between UEV and LEV(P > 0.05).Comparing the degree of vertebral rotation in the prone position(O-arm)with that in the left position(right thoracic approach,O-arm),it can be seen that the degree of vertebral rotation in the left prone position of AVR is less than that in the prone position,with an average difference of 7.18 degrees and a standard deviation of 2.23 degrees,P=0.000,and the difference is significant(P<0.05).When UEV and LEV were in the left lateral position,the rotation of vertebral body was less than that in the prone position,the average reduction was 2.62 and 1.89 and the standard deviation was 1.91 and 1.37 respectively.However,there was no significant difference in vertebral rotation between UEV and LEV(P > 0.05).Cobb angle of scoliosis is highly correlated with AVR in prone position.Cobb angle of scoliosis is slightly or nearly unrelated to UEVR,AVAUEVR,LEVR and AVBLEVR in prone position.Cobb angle of kyphosis is only slightly or nearly unrelated to AVR,UEVR,AVAUEVR,LEVR and AVBLEVR in prone position.The correlation coefficient of AVAUEVR was the lowest,and that of LEVR and AVBLEVR was the highest.Correlative analysis of rotation in left lateral position,Cobb angle of kyphosis was moderately correlated with AVR.The correlation between scoliosis Cobb angle and AVR,UEVR,LEVR,kyphosis Cobb angle and UEVR,LEVR is low.2.A total of 40 patients were enrolled in the study of the relationship between the main thoracic apex and the aorta.The Cobb angle of the main thoracic curve was 46.5-80.7 degrees in 18 patients in the posterior approach group,with an average of 60.09±11.62 degrees,and the kyphosis angle of T5-T12 was 7.3-52.1 degrees,with an average of 21.68±11.36 degrees.The Cobb angle of the main thoracic curve was 35.1-75 degrees in 22 patients in the anterior surgery group,with an average of 46.97 ±8.58 degrees,and the kyphosis angle of T5-T12 was 0-35.2 degrees,with an average of 12.12±11.5 degrees.The average difference between the prone position of main thoracic curve AVR in posterior supine position(MRI)and intraoperative prone position(O-arm)was 2.71 degrees(P < 0.05).The vertical distance between aorta and vertebral canal line c was larger in prone position than in supine position(P < 0.05).The average difference was 2.24 mm(P < 0.05).The prone position of aortic vertebral angle(AVA or delta)had significant difference(P < 0.05).Compared with supine position,the average difference was 4.45 degrees.The values of a,b,d,ψ,θ in the prone position and supine position were different,but the difference was not significant(P > 0.05).In the supine position(MRI)before posterior approach and in the left supine position(O-arm)during anterior approach,the difference between the supine position of AVR in main thoracic curve and that in left supine position was 4.24 degrees(P < 0.05),and the average difference between the supine position of AVA in aortic vertebral body angle(AVA or δ)and that in left supine position was 9.25 degrees(P = 0.036,P < 0.05),a,b,c,d,ψ,θ.There was no significant difference in the values of theta supine position and left supine position(P > 0.05).In prone position(O-arm)and left position(O-arm),the difference between prone position of AVR in main thoracic curve and left position was 6.95 degrees(P < 0.05).In aortic vertebral angle(AVA or δ),the difference between prone position and left position was 4.8 degrees,and the difference between left position and prone position was not statistically significant(P < 0.05).Significance(P > 0.05);there was no significant difference between a,b,c,d,ψ and θ(P > 0.05).In supine and prone position,the degree of Cobb angle in supine position was positively correlated with a,ψ andθ,and the Cobb angle in kyphosis was moderately positively correlated with a and δ.AVR in supine position was slightly correlated with distances and angles.Intraoperative prone position was found that the degree of scoliosis Cobb compaired with index are highly correlated,the kyphosis Cobb and observation indexes only mild relevant or irrelevant,AVR preoperative and intraoperative AVR both with intraoperative a,d,ψ,θ was highly correlated,the same index under two kinds of positions,AVR,a,b,c,d,δ(AVA),ψ,θ,moderately correlated,significance is obvious.The correlation analysis in the left lateral position during anterior surgery showed that the degree of the scoliosis Cobb angle and the AVR,a,b,c,d,δ,ψ andθ correlation index were very small,even close to unrelated.Cobb angle of kyphosis is moderately correlated with b,c,d and δ.The AVR in the left lateral position was slightly correlated with the distances and angles,and nearly zero correlated withψ andθ,that is,it was not correlated.Conclusions1.In the study of vertebral rotation,AVR: prone position > supine position > left lateral position;UEVR: prone position > supine position > left lateral position;AVAUEVR: prone position > supine position;LEVR: supine position > prone position> left lateral position;AVBLEVR: supine position > prone position.The AVR,UEVR and AVAUEVR of thoracic curve in prone position increased compared with supine position,while the LEVR and AVBLEVR in supine position decreased.AVR of main thoracic curve is the largest among the three positions,suggesting that clinicians should pay more attention to the correction of AVR in actual operation.2.By comparing the three positions,we can find that the relationship between AVR is prone position > supine position > left side position;and the relationship between AVA : left side position > prone position > supine position: But because the positive or negative values of the measurements represent the position and direction of the aortic center relative to the vertebral center,while assisting other related distances.Measurements show that the aorta moves gradually to the ventral and right front in three positions(supine-prone-left side).Understanding this trend provides an important auxiliary role in ensuring accurate and safe placement of nails and avoiding aortic injury.In addition to assisting the safe placement of screw during operation,the O-arm surgery can also understand the changes of the relationship between vertebral body and aorta in scoliosis patients in different positions.It is an important assistant means and approach in clinical research. |
