Spontaneous shoulder correction and instrumentation strategy of upper thoracic curve in adolescent idiopathic scoliosis

English Keywords:Scoliosis  Shoulder balance  Surgical management

English Abstract:

  【Abstract】 Objectives: To evaluate the spontaneous correction of shoulder cosmetic difference(SCSC) in adolescent idiopathic scoliosis(AIS) and the strategy of choosing upper instrumented vertebra(UIV). Methods: 56 consecutive Lenke Ⅰ AIS patients followed up for 2 to 5 years were enrolled, the preoperative main thoracic(MT) Cobb angle was 57.65°±12.28° and proximal thoracic(PT) Cobb angle was 20.34°±9.52°. Preoperative shoulder balance, flexibility of PT, and UIV were defined as following, when lifting right shoulder, 10 patients with non-rigid PT were chosen the vertebra just below the end vertebra(EV-1); 7 patients with rigid PT were chosen the end vertebra(EV). When encountering shoulder balance and non-rigid PT, 7 patients were chosen the vertebra just above end vertebra(EV+1), 7 patients were chosen T3. For patients with rigid PT, 5 of them were chosen T4, 6 of them were chosen T3. When lifting left shoulder, 4 patients with non-rigid PT were chosen EV+1; Patients with rigid PT, 1 of them was chosen T4, 9 of them were chosen T3. T-test was used to evaluate the difference of shoulder cosmetic difference(SCD) after surgery immediately and at final follow-up. The subjective evaluations of shoulder balance from patients and parents were also recorded. Poor subjective evaluation was got when patient or parent considered shoulder unbalanced. Photographs, radiographic images and subjective evaluation were assessed to summarize the strategy to choose UIV based on SCCS. Results: The correction rate was (66.76±10.21)% at final follow-up. Coronal balance improved to 0.67±0.56cm, and T2-T5 kyphosis was 17.23°±7.28°. 1 patient had the subjective perception of left shoulder lifted in two years of follow-up, all the other patients were satisfied with their shoulder balance and had no experience of other complication. At preoperation, postoperation immediately and final follow-up, the SCD was 1.04±0.24cm, 0.92±0.22cm and 0.63±0.16cm respectively, number of patients with SCD≥1cm was 31, 23 and 5 respectively. There was significant difference between SCD after surgery immediately and that at final follow-up(t=7.98, P＜0.001). The maximum correction of shoulder cosmetic(SCD) was 1.69cm. Patients with successful results and the strategies to choose UIV: patients with preoperative right shoulder lifted and non-rigid PT when choosing EV-1, patients with preoperative right shoulder lifted and rigid PT when choosing EV, patients with preoperative balanced shoulder and non-rigid PT when choosing EV+1 or T3, patients with preoperative balanced shoulder and rigid PT when choosing T3, all got CSD＜1cm and subjective satisfaction of shoulder balance. Patients with preoperative left shoulder lifted and non-rigid PT when choosing EV+1, 1 of whom had CSD as 1.06cm, but gained subjective satisfaction. Patients with preoperative left shoulder lifted and rigid PT when choosing T3, 1 of whom had CSD as 1.02cm, gained subjective satisfaction. Patients with unsuccessful results and the strategies to choose UIV: Patients with preoperative balanced shoulder and rigid PT when choosing T4, 2 of whom had CSD as 1.45cm and 1.54cm, 1 of the two considered left shoulder lifted in two years follow-up. Patients with preoperative left shoulder lifted and rigid PT when choosing T4 had CSD as 1.52cm at final follow-up. Conclusions: Cosmetic shoulder balance maybe developed in most patients after surgery. The strategy to choose UIV based on SCSC is as follow, when lifting right shoulder, patients with non-rigid PT should choose EV-1, while rigid PT choosing EV. When encountering shoulder balance, patients with non-rigid PT should choose EV+1, while rigid PT choosing T3. When lifting left shoulder, patients with non-rigid PT choose EV+1, while rigid PT choosing T3.