Analysis Of Orthopedic Programs On The Digital Reconstruction Of The Spine-pelvis Sagittal Balance Of Adult Scoliosis

Objective:To direct introperative correction and reconstruct good spinopelvic sagittal balance in adult scoliosis by designing the shape of introperative correction segments.Methods:Pelvic tilt (PT) was confirmed by pelvic incidence of patients. Sacral slope was confirmed by a formula, that is, sacral slope (SS)=pelvic incidence(PI)-pelvic tilt(PT).Lumbar lordosis type which is need to be reconstructed was confirmed by sacral slope (SS), then lumbar lordosis angle, apex, number of vertebral bodies of composition of lumbar lordosis, angle of upper arc of lumbar were obtained. Firstly, fixing pelvic tilt(PT) was to confirm the location of femoral heads and sagittal plane of sacrum and to ensure pelvic tilt(PT) designed was constant. Then a perpendicular line was drawn from the anterior corner of sacrum. The midpoint of anterior C7was fixed at this perpendicular line. Spine can move up and down at the center of C7((movement limitation can guarantee sagittal vertical axis [SVA]≈0).Relative length of lower arc of lumbar lordosis Apex which was classified by sagittal function was made by apex.The location of apex can be confirmed by angle and length of arc.Length of upper arc of lumbar lordosis was confirmed by intersection point of lumbar lordosis tilt angle of oblique line and20degree of upper arc of lumbar lordosis.From T1vertebral body to vertebral body of apex of upper arc of lumbar lordosis was regarded as the entirety. Then lower radius of thoracic kyphosis was adjusted to be equaled to the upper radius of lumbar lordosis, which can obtain anterior arc of spine and the shape of correction segment that is to direct surgery tactic. Twenty-five patients of adult scoliosis who was administrated consecutively in our study institute from May2009to January2011represented spinopelvic sagittal imbalance in radiographic inspection. Twenty patients represented forward (SVA>2.5cm), five retrovert(SVA<-2.5cm).The shape of introperative correction segments was confimed by using methods above, which are to direct surgery. Full-length standing coronal and sagittal radiographs were collected after surgery. Preoperative and postoperative thoracic kyphosis,lumbar lordosis,pelvic tilt(PT),sagittal vertical axis(SVA),coronal Cobb angle, lateral slip, VAS scores, ODI scores was obtained.Results:All patients’ spinopelvic sagittal imbalance were reconstructed after surgery. Sagittal parameter were all reached to SAV<5cm PT<20°、PI-9°<LL<PI+9°.All patients’thoracic kyphosis、 lumbar lordosis, pelvic tilt(PT),sagittal vertical axis(SVA),coronal Cobb angle,lateral slip,coronal balance,sagittal balance were obtained good correction after surgery compared with preoperation values (P<0.01), VAS scores and ODI scores were improved after surgery compared with preoperation values (P<0.01)Conclusions:Reconstruction of the ideal spinopelvic sagittal balance of adult scoliosis can be obtained by designing theoretically the good shape of intraoperative correction segments before sur-gery.