Posterior-only correction surgery for idiopathic scoliosis Lenke type 5c: differences of strategies and outcomes between adult patients and adolescent patients

Purpose To compare radiographic parameters, and functional and surgical outcomes between lumbar adolescent idiopathic scoliosis (AIS) and lumbar adult idiopathic scoliosis (AdIS). Methods A retrospective study was performed to identify Lenke 5c type AIS and AdIS patients from our scoliosis database who had undergone posterior surgical treatment for scoliosis. Preoperative and postoperative radiographic and clinical outcomes were compared between the two groups. Results A total of 22 patients were included in AdIS group, and 44 matched patients in AIS group. AdIS group had significantly larger L3 and L4 tilt and translation than AIS group ( P < 0.05). AdIS group had larger T10-L2 angle and smaller T5–T12 angle ( P < 0.05). AdIS group had higher VAS scores ( P < 0.05) and pain domain of SRS-22 scores ( P < 0.05) as compared to AIS group. Correlation analysis demonstrated positive relationship between VAS scores and T10-L2 angle ( r = 0.492, P < 0.05). AdIS group was fused longer than AIS group ( P < 0.05). Cobb angle of TL/L curve was larger and correction ratio was smaller at AdIS group ( P < 0.05). AdIS group still had significantly larger L3 and L4 tilt and translation than AIS group ( P < 0.05). CT measurements demonstrated larger postoperative vertebral body rotation at apical vertebrae and LIV at AdIS group ( P < 0.05). Vertebral correction ratio was smaller at AdIS group ( P < 0.05). Conclusion Lenke 5c AdIS patients had greater preoperative and postoperative L3 and L4 tilt and translation, as well as less correction of major curve and vertebral body derotation than AIS patients. However, the incidence of adding-on was similar between the two groups.