The Effect Of Vectors Associated With Main Curve And Overall Curves On Preoperative And Postoperative Coronal Trunk Balance In AIS

【Objectives】To investigate the effect of vectors associated with main curve and overall curves on preoperative and postoperative on coronal trunk balance(CTB) in adolescent idiopathic scoliosis(AIS). 【Methods】Retrospective analysis 22 AIS patients who received posterior pedicle screw and rod system treatment in Fujian Province Hospital from 2011 to 2013. All patients had pre- and postoperative standing upright posteroanterior and lateral radiographs,as well as preoperative supine left and right side-bending radiographs. Use vector concept which means size and direction in physics. Analysis the vectors associated with main curve、overall curves and the offset of coronal C7 plumb line(C7PL) relative to center sacral vertical line(CSVL) during pre- and postoperative. 【Results】22 AIS patients, male 5 cases, female 17 cases, average 14.3 years old(range 12.2-18.0 years) during the operation, average follow-up time was 12 months(range 6-24 months). In pre- and postoperation, The angle of main curves、overall curves 、 the offset distance of C7PL-CSVL have significant differences(P<0.05,t are 9.37、2.21、8.56, respectively). In preoperation, The vectors of C7PL-CSVL had significant associated with the vectors of main curves(r=0.447,P<0.05). In preoperation, The vectors of C7PL-CSVL had significant associated with the vectors of overall curves(r=0.510,P<0.01). In pre- and postoperation, The angle of main curves and overall curves had no significant effect on the offset distance of C7PL-CSVL(P>0.05). Correction amount of major curves have no significantly associated with the change amount of C7 PL relative to CSVL(C7PL-CSVL) distance(P>0.05). Correction rate of major curves have no significant associated with the change rate of C7PL-CSVL distance(P>0.05). 【Conclusions】 The key of intervention(brace、operation) is to prevent the whole spine offset to the convex direction of major curve and overall curves in AIS patients which may tend to have coronal trunk imbalance. There is no directly relationship between the cobb angle of curves and the coronal offset distance of C7PL-CSVL in AIS. There is no directly relationship between the main curve correction and the coronal offset distance of C7PL-CSVL correction.