539 - Influence of Synchronous Counter-derotation of Apical Vertebral Region...

#539 Influence of Synchronous Counter-derotation of Apical Vertebral Region, Lowest Instrumented Vertebra and Pelvis on the Choice of Lowest Instrumented Vertebra in Posterior Correction for Idiopathic Double Thoracolumbar Curves/Lumbar Curve

Lumbar Therapies and Outcomes

Poster Presented by: H. Fang

Author(s):

H. Fang (1)
H. Wang (1)
A.M. Chen (1)
F. Li (1)
W.F. Yin (1)
Z.J. Xu (1)
F. Liu (1)

(1) Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Department of Orthopedic Surgery, Wuhan, China

Abstract

Objective: To evaluate the clinical value and significance of synchronous counter-derotation of apical vertebral region, lowest instrumented vertebra and pelvis by discussing its influence on the choice of lowest instrumented vertebra in posterior correction for idiopathic double thoracolumbar curves/lumbar curve.

Methods: 51 cases of idiopathic scoliosis (double thoracolumbar curves/lumbar curve) were selected for a retrospective analysis. The cases were subjected to three-dimensional correction by synchronous counter-derotation of apical vertebral region, lowest instrumented vertebra and pelvis. Lumbar curve fusion selection criteria: 1. Single thoracolumbar/lumbar curve with the center of apical vertebra deviating from the stable region, complicated with rotation ≥ II° and/or kyphosis. 2. Double/triple thoracolumbar/lumbar curves with the concave edge of the apical deviating from the stable region, stress roentgenogram showing the center of apical vertebra deviating from the stable region; or rotation of apical vertebral body ≥ III°, stress roentgenogram ≥ II° or unable to derotate; or complicated with thoracolumbar junctional kyphosis; thoracolumbar/lumbar convex Bending phase ≥ 30°. Selection criteria of lowest instrumented vertebra (LIV): the LIV is the vertebra the center of which deviats from stable region, or the first vertebra the concave edge of which deviating from the lowest vertebral body of CSVL (the second vertebra above the stable region). Pre and post operation, Cobb´s angle of scoliosis, intervertebral angle and inclination angle of LIV , rotation angle, coronal vertical alignment (CVA), sagittal vertical alignment (SVA) were compared; postoperative follow-ups were 18-51 months.

Results: The Cobb´s angle of thoracic curve was corrected from 62.1°±13.8° preoperatively to 11.7°±5.6° with a correction rate of 78.2%±15.4% postoperatively, and to 14.5°±7.1° with a correction rate of 75.2%±16.1% at the latest follow-up; there was statistical difference between pre- and postoperative result. Cobb´s angle of thoracolumbar/lumbar curve was corrected from 57.3° ±15.6°preoperatively to 10.4° ±4.2°with a correction rate of 82.8%±13.4% and to 12.5°±6.1° with a correction rate of 77.3%±11.6% at the latest follow-up; there was statistical difference between pre- and postoperative result. (P< 0.01). Preoperatively, postoperatively and at the latest follow-up, the intervertebral angle of LIV was respectively 4.7°, 2.1° and 2.6°; the inclination angle of LIV was respectively 23.6°, 2.8° and 3.4°(P<0.01); there was statistical difference; the offset distance of LIV was respectively 3.9cm, 0.22cm, 0.28cm; the rotation angle was respectively I°-II°, 0°-I° and 0°-I°; preoperatively, postoperatively and at the latest follow-up, CVA was respectively 2.4cm, 0.2cm, 0.5cm (P< 0.05). All the cases presented with fair reconstruction of sagittal plane and physiological curvature; preoperatively, postoperatively and at the latest follow-up, SVA was respectively 2.7cm, 1.3cm and 0.8cm (P< 0.05). Postoperatively, the functions of 2-4 lumbar vertebral segments were maintained.

Conclusion: By synchronous counter-derotation of apical vertebral region, lowest instrumented vertebra and pelvis, idiopathic double thoracolumbar curves, thoracolumbar/lumbar curve can be effectively corrected and maintained, spinal balance can be reconstructed and the number of fusion segments can be decreased at maximum to maintain the functions of lumbar vertebra.

Keywords: scoliosis, posterior correction, derotation