Rotation Assessment in Adolescent Idiopathic Scoliosis With Rod Derotation

Abstract

Objective:Adolescent idiopathic scoliosis (AIS) is characterized by rotational and lateral deformity of the spine. The measurement of vertebral rotation is important for prognosis and treatment. Our objective was to evaluate whether the Nash-Moe method can be used to measure axial deformity correction with surgical treatment using the rod derotation maneuver at both the apex and extremities of the deformity in patients with AIS.Methods:Rotation was assessed using the Nash and Moe criteria, on preoperative and postoperative radiographs. We also evaluated the severity on the coronal plane using the Cobb method, ratio of correction achieved, screw density, and number of vertebrae involved in the instrumentation.Results:The Cobb method correction average was 54.8%. When we disregarded vertebrae that presented preoperative Nash-Moe grade 0, the average measurable correction was 54.5% in the first non-instrumented vertebra above, 69.2% in the first instrumented vertebra, 32.2% in the apical vertebra, 36.8% in the last instrumented vertebra, and 30% in the first non-instrumented vertebra below. In our study, 32.14% of the patients presented a measurable correction in the apical vertebra.Conclusion:On the axial plane, correction can be satisfactorily evaluated using the Nash-Moe method. Level of Evidence VI. Case Series.

Three-Dimensional Assessment of Vertebral Derotation in Adolescent Idiopathic Scoliosis: Review of a Surgical Technique and Its Success in Achieving Derotation in the Instrumented and Uninstrumented Spine

“…Improvements in AVR have been extensively documented after AIS surgery, but measurement of such derotation has varied. [28][29][30][31] In 55 patients undergoing AIS surgery, Kato et al 29 implemented preoperative and postoperative 3D EOS imaging and found that AVR was significantly corrected after surgical correction using the direct vertebral derotation technique (55% vs 36%, P = .03). In a study of 30 patients with AIS undergoing corrective surgery, Demura et al 28 showed improved rotation of the both the instrumented thoracic curve and uninstrumented lumbar curve using CT-based measurements.…”

“…Chang et al 30 used the Nash-Moe technique to show significant improvement in 64 patients with AIS treated with both rod derotation and direct vertebral rotation techniques. Although previous authors have recommended the x-ray-based Nash-Moe method for rotation assessments, 31 more recent studies have used the same 3D techniques used in the current study. 1,11,17,18 In 23 type 1 AIS patients, Pasha et al 17 reported significant improvement in rotation of the instrumented main thoracic curve and uninstrumented lumbar curve using 3D imaging.…”

Effect of Direct Vertebral Rotation on the Spine Parameters (Coronal and Sagittal) in Adolescent Idiopathic Scoliosis

“…The direction of DVR in the lowest instrumented vertebra (LIV) and its effect on the uninstrumented curve are still undetermined [4,10,11]. It has been thought that the direction of DVR in the LIV might differ depending on the lumbar modi er, as described by Lenke et al [12][13][14].…”

“…The authors of recent studies have focused on the radiologic outcomes of DVR in scoliosis surgery [9][10][11][12][13][14]. However, its e cacy and safety remain to be determined.…”

“…Some suggest that DVR creates hypokyphosis on thoracic kyphosis, presents an increased risk of screw pullout, and prolongs operative time without bene ts [15][16][17]. Surgical treatment can lead to improvements in self-con dence, selfimage, cosmetic and life satisfaction, and back pain [10][11][12][13][14]. Thoracic curves of > 50° and the lumbar component of a double major curve will progress into adult life, especially in those with more apical rotation.…”