Objective
Proximal junctional fracture (PJFx) at the uppermost instrumented vertebra (UIV) or UIV+1 is the most common mechanism of PJF. There are few studies assessing the radiographic progression after PJFx development. Therefore, this study sought to identify the risk factors for radiographic progression of PJFx in surgical treatment for ASD.
Methods
In this retrospective study, among 317 patients aged > 60 years who underwent ≥5-level fusion from the sacrum, 76 with PJFx development were included. According to the change in proximal junctional angle (PJA), two groups were created: Group P (change ≥10°) and Group NP (change <10°). Patient, surgical, and radiographic variables were compared between the groups to demonstrate risk factors for PJFx progression using uni- and multivariate analysis. The receiver operating characteristic (ROC) curve was used to calculate cutoff values. Clinical outcomes, such as visual analog scale (VAS) scores for back and leg pain, the Oswestry Disability Index (ODI) score, and the Scoliosis Research Society (SRS)-22 score, and revision rate were compared between the two groups.
Results
The mean age at the index surgery was 71.1 years, and there were 67 women enrolled in the study (88.2%). There were 45 patients in Group P and 31 in Group NP. A mean increase of PJA was 15.6° (from 23.2° to 38.8°) in Group P and 3.7° (from 17.2° to 20.9°) in Group NP. The clinical outcomes were significantly better in Group NP than Group P, including back VAS score, ODI value, and the SRS-22 scores for all items. Revision rate was significantly greater in group P than in group NP (17.8% vs. 51.6%, p=0.001). Multivariate analysis revealed that overcorrection relative to the age-adjusted ideal pelvic incidence (PI)–lumbar lordosis (LL) target at the index surgery (odds ratio [OR]=4.484, p=0.030], PJA at the time of PJFx identification (OR=1.097, p=0.009), fracture at UIV versus UIV+1 (OR =3.410, p=0.027) were significant risk factors for PJFx progression. The cutoff value of PJA for PJFx progression was calculated as 21° using the ROC curve.
Conclusions
The risk factors for further progression of PJFx were overcorrection relative to age-adjusted PI–LL target at the index surgery, PJA > 21° at initial presentation, and fracture at the UIV level. Close monitoring is warranted for such patients not to miss the timely revision surgery.

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.