Objective
To investigate stiffness-related disability (SRD) following surgical treatment in adolescent idiopathic scoliosis (AIS) patients particularly with respect to the lowest instrumented vertebra (LIV).
Summary of Background
Extensive spinal fusion inevitably results in loss of mobility which may induce SRD during activities of daily living. Few studies have examined SRD after surgical correction for AIS.
Methods
Patients who underwent surgical correction for AIS between 2014 and 2021 and were followed up for two years were included. The degree of SRD was evaluated using the Stiffness-Related Disability Index (SRDI) which consists of four categories, each containing three questions, giving a total of 12 components of the questionnaire. The SRDI scores were compared according to the (LIV) levels. Correlation analysis was performed to examine the relationship between the SRDI and legacy health-related quality of life (HRQOL) measurements.
Results
This study included 174 patients (47 males, 127 females) with a mean age of 13.8 years. Among the 12 items of the SRDI, the scores of nine items showed a significant increase after surgery. The total sum of the SRDI scores also significantly increased after surgery. Pearson correlation analysis showed that the SRDI scores were significantly correlated with ODI (Oswestry disability index), nearly all domains, and the total sum of SRS-22 (Scoliosis Research Society-22 questionnaire), and SF-36 (Short Form 36 health questionnaire). No differences in the SRDI score were found among cases with the LIV between T12 and L3. However, The SRDI scores of patients with LIV at L4 were significantly higher than those of patients with other LIV levels. .
Conclusions
Various degree of SRD occurred after spinal fusion for AIS. The SRDI significantly correlated with the HRQOL measures. The SRDI score was highest in patients with the LIV at L4 compared to those with other LIV levels.

Background
The Selective thoracic fusion (STF) may be associated with risk of postoperative coronal decompensation, lumbar decompensation and adding-on phenomenon, which can lead to persistence of the lumbar curve and consequently to deviation of the trunk. Therefore, the STF is the most debatable issue as the optimal surgical correction in adolescent idiopathic scoliosis with Lenke 1C curves.
Methods
A total of 30 patients with adolescent idiopathic scoliosis with Lenke 1C curves who underwent STF between 1996 and 2017 were included. Minimum follow-up duration was five years. We analyzed the incidence of coronal decompensation, lumbar decompensation, distal adding-on phenomenon and trunk shift in these patients for radiographic adverse event. Clinical outcome was assessed by using the Scoliosis Research Society (SRS)-22r scores.
Results
The mean age at the time of surgery was 13.8±2.9 years. The mean follow-up duration was 80.4±12.3 months. The Cobb’s angle for main thoracic curve improved by 59.6% (p<0.001), and also The Cobb’s angle for thoracolumbar/ lumbar curve improved by 40.5% comparing preoperative and postoperative values (p<0.001). There was significant improvement in the Cobb’s angle for main thoracic and Thoracolumbar/lumbar curve comparing preoperative and last follow-up values (p<0.001). At last follow-up, the coronal balance was 10.3 ± 9.1 that significant improved from the immediate postoperative value (p=0.033). The incidence of coronal decompensation, lumbar decompensation, adding-on and trunk shift in our cohort was 16.7%, 10.0%, 13.3% and 10.0% respectively. The average SRS score at last follow-up in patients with radiographic adverse events was 4.3±0.5. That of patients without adverse events was 4.4±0.6. All domains between patients with and without adverse events had no statistical significance difference.
Conclusions
Selective thoracic fusion in Lenke 1C curves have acceptable risk of coronal decompensation, lumbar decompensation, distal adding-on, trunk shift. However, no revision surgery was required in these patients after long term follow-up. Therefore, STF in Lenke 1C curves seems to be enough.

Purpose
To evaluate the impacts of regional and socioeconomic factors on adolescent idiopathic scoliosis (AIS) diagnosis and treatment using national datasets of the Korean National Health Insurance System. The prevalence of, and therapeutic trends in, AIS are affected by a variety of environmental factors.
Materials and Methods
We analyzed random samples from datasets (10% of all entries) between 2012 and 2018, including in terms of patient demographics, residential status (a “special city”, and urban, and rural regions) and socioeconomic status (SES) based on health insurance premiums (which distinguish National Health Insurance and Medical Aid [MA] beneficiaries).
Results
The AIS prevalence was approximately 1.6-fold higher in females than in males, whereas the rate of male surgery was approximately 1.5-fold higher than that in females. AIS prevalence was higher among National Health Insurance beneficiaries (in all years), whereas the surgery rate was higher among MA beneficiaries (in most years). In all years, AIS prevalence was significantly higher among special city residents than in urban and rural residents. However, the surgical treatment rates were higher in the latter regions.
Conclusions
Our nationwide evaluation revealed AIS prevalence rates and therapeutic trends. AIS epidemiology varies by region and economic status.