EUROSPINE 2017 Scientific Programme oral presentations Friday, 21 September, 2018 15:50 – 17:00 Complications, Infection, Epidemiology 70 THE SHOULDER BALANCE REBUILDING IN SEVERE THORACIC SCOLIOSIS WITH A LOWER SHOULDER ON THE CONCAVE SIDE: EXPERIENCE FROM A SINGLE INSTITUTION INVOLVING 84 PVCR PATIENTS OVER 13 YEARS Tao Li , Yingsong Wang , Jingming Xie , Ying Zhang , Zhi Zhao, Zhiyue Shi , Ni Bi Department of Orthopedics, The 2nd Affiliated Hospital of Kunming Medical University, Yunnan Province, P.R.China Background: Should imbalance was more common and more serious in severe scoliosis patients than it in AIS. Because of the special correction mechanism, a well deformity correction and well trunk balance rebuilding could lead to a new shoulder imbalance in PVCR. There was no study and guideline about how to rebuilding the should balance of the severe scoliosis patients in PVCR. Objective: To analyze the clinic and imaging data of the severe scoliosis patients received PVCR, then investigate the strategy of shoulder balance rebuilding in severe thoracic scoliosis received PVCR. Methods: Severe thoracic scoliosis treated with PVCR were retrospectively reviewed. Patients with pelvic obliquity>2 cm, leg length discrepancy, muscle weakness of the lower limbs and a higher shoulder on the concave side were excluded. All patients performed routine posteroanterior standing radiographs before and after surgery. The clinic data, shoulder height (SH), the Cobb angle and trunk shift were measured. All patients followed the below steps to rebuild shoulder balance in PVCR:1. Reconstruct trunk shift<2cm; 2.The correction of the major curve was the main force to rebuild the shoulder balance and would be result in elevating the shoulder on the concave side (50% correction rate: 2.5cm; 60% correction rate: 3cm; 70% correction rate: 4cm). It should be matched with the shoulder imbalance before surgery. 3. The correction of proximal fixation segment can further adjust the shoulder balance, but its efficiency is low (<1cm). 4.Sacrificed part of the trunk balance to reconstruct the shoulder balance was the last resort. 5.Patients fixed to T3 have a lower potential for remodeling the shoulder balance and the potential would be loss when fixed to T2. Results: The study included 84 severe thoracic scoliosis patients, aged 12-25 years old. The mean preoperative major curve of 118±17° was corrected to 43±13° (correction rat: 65±11%). The trunk shift was 2.47±0.56cm before surgery and 1.56±0.36cm after surgery. The average preoperative SH was 26.7±6.9mm, the average postoperative SH was 11.3±4.1mm (mean change: 31.6mm)(P <0.05). 69(82%) patients showed shoulder imbalance before surgery and 19(23%) showed shoulder imbalance after surgery (p <0.05). Conclusions:Preoperative shoulder imbalance in patients with severe scoliosis is more common and more severe. The special correction mechanism of PVCR has a special impact on the reconstruction of the patient's shoulder balance, often resulting in new shoulder imbalances. The strategy of reconstructing the shoulder balance presented in the study can guide the surgeon to better reconstruct the shoulder balance during PVCR.