Comparison of Surgical Outcome of Adolescent Idiopathic Scoliosis and Young Adult Idiopathic Scoliosis: A Match-Pair Analysis of 160 Patients

STUDY DESIGN: Retrospective study. OBJECTIVE: To investigate if the surgical outcome of young adults was equivalent to adolescents for surgical correction of thoracic adolescent idiopathic scoliosis (AIS). SUMMARY OF BACKGROUND DATA: Despite numerous reports on the satisfactory surgical correction, some AIS patients or families still have the assumption that delay of surgery into young adulthood may be more beneficial. Hence, the strict paired analysis of clinical outcome between AIS and adult idiopathic scoliosis (AdIS) is required, which lacks report in the current literature. METHODS: This is a retrospective 1:1 matched cohort. A total of 80 pairs were recruited with the following inclusion criteria: (A) female Lenke Type 1A or 1B idiopathic scoliosis; (B) selective fusion; (C) adolescents aged 10 to 18 years and young adults aged 19 to 29 years; (D) one-stage posterior approach; (E) all-pedicle-screws instrumentations; (F) major Cobb angle 45° to 80°. AIS patients and AdIS patients were matched for apex, major thoracic curve magnitude (±5°), lumbar curve magnitude (±5°), time of surgery (±6 month), and follow-up (±6 month). RESULTS: The age at the time of surgery in AdIS patients averaged 22.21years, significantly larger than that of AIS patients (22.21 vs. 14.47 yr). AdIS patients had significant lower curve flexibility. Accordingly, lower correction rate and larger postoperative main Cobb angle were found in AdIS patients. Regarding quality of life, no significant difference was observed between the two groups during follow-up. CONCLUSION: The results may provide evidence for spine surgeons to communicate with AIS patients and their families regarding pros and cons of the delay of surgery into young adulthood. AIS patients would gain better radiographic curve correction compared with matched AdIS patients due to more flexibility. When considering potential curve progression, the radiographic outcome of AdIS may be even worse. Whereas delaying to adulthood may have similar health-related quality of life and reduce the risk of adding-on phenomenon. LEVEL OF EVIDENCE: 3.