Study design: A retrospective case series.
Objective: This study aimed to report the sagittal outcome measures in patients with Lenke type 5C adolescent idiopathic scoliosis (AIS) undergoing thoracolumbar/lumbar (TL/L) fusion surgery.
Summary of background data: Previous studies have demonstrated coronal correction of Lenke type 5C AIS by selective TL/L fusion surgery. However, little is known about the sagittal influence of selective TL/L curve correction in Lenke type 5C AIS.
Methods: Thirty-nine patients with Lenke type 5C AIS underwent selective posterior TL/L curves fusion (mean age, 15.9 ± 2.1 yrs). Preoperative and postoperative radiographic and clinical parameters were analyzed at a minimum 2-year follow-up period. Radiographic parameters were compared between patients with Lenke sagittal modifier normal (Group N) to those with Lenke sagittal modifier minus (Group M).
Results: The main TL/L Cobb angle was 46.3° ± 7.7° preoperatively and 20.7° ± 5.3° (P < 0.0001) at 2-year follow-up. Also, thoracic kyphosis (TK) (T1-12) angle was 29.0° ± 11.3° preoperatively and 36.4° ± 10.3° at follow-up (P < 0.001), and TK (T5-12) angle was 18.1° ± 10.2° preoperatively and 25.9° ± 8.9° at follow-up (P < 0.001). The cervical lordosis (CL) was 9.6° ± 11.6° preoperatively and 6.1° ± 10.9° at follow-up (P = 0.037). Compared with the Lenke sagittal modifier groups, preoperative TK (T1-12), TK (T5-12), thoracolumbar kyphosis (TLK), and CL were significantly different from both the groups; and after the surgery, no significant differences in these parameters were observed between the two groups.
Conclusion: After the selective TL/L posterior fusion surgery in patients with Lenke type 5C AIS, the sagittal alignment profile, including TK, TLK, C7 sagittal vertical axis, T1 slope, and CL, was significantly changed. With regard to the sagittal aspect, selective TL/L surgery was more likely to affect Group M than Group N.
Level of evidence: 4.