Independent risk factors of proximal junctional kyphosis with vertebral fracture after spinal long fusion: Survivorship analysis of adult spinal deformity surgery patients.

OBJECTIVE: This study aimed to identify risk factors for postoperative proximal junctional kyphosis (PJK) with vertebral fracture in adult spinal deformity (ASD) patients. We performed a survival analysis considering various factors, including osteoporosis. METHODS: This single-center retrospective study included 101 ASD patients (mean age: 67.2 years, mean follow-up: 8.1 years). We included patients aged ≥ 50 years with abnormal radiographic variables undergoing corrective long spinal fusion. The main outcome measure was PJK with vertebral fracture, analyzed based on patient data, radiographic measurements, sagittal parameters, bone mineral density, and osteoporosis medication. RESULTS: PJK occurred in 37.6% of patients, with vertebral fracture type 2 accounting for 65% of these cases. Kaplan-Meier analysis indicated a median PJK-free survival time of 60.7 months. Existing vertebral fracture (grade 1 or higher or grade 2 or higher) was a significant risk factor for PJK with vertebral fracture, with hazard ratios of 4.58 and 5.61, respectively. The onset time of PJK with vertebral fracture was 1.5 months postoperatively, with 44% of these cases occurring within 1 month and 64% within 2 months. CONCLUSIONS: PJK with vertebral fracture affected 25% of ASD patients, emphasizing the importance of osteoporosis evaluation. Existing vertebral fracture emerged as a significant independent risk factor, surpassing bone mineral density. This study provides valuable insights for spine surgeons, highlighting the need to provide osteoporosis treatment and emphasize potential postoperative complications during discussions with patients.

Predictive role of FRAX© for postoperative proximal junctional kyphosis with vertebral fracture after adult spinal deformity surgery.

PURPOSE: To identify risk factors, including FRAX (a tool for assessing osteoporosis) scores, for development of proximal junctional kyphosis (PJK), defined as Type 2 in the Yagi-Boachie classification (bone failure), with vertebral fracture (VF) after surgery for symptomatic adult spinal deformity. METHODS: This was a retrospective, single institution study of 127 adults who had undergone corrective long spinal fusion of six or more spinal segments for spinal deformity and been followed up for at least 2 years. The main outcome was postoperative development of PJK with VF. Possible predictors of this outcome studied included age at surgery, BMI, selected radiographic measurements, bone mineral density, and 10-year probability of major osteoporotic fracture (MOF) as determined by FRAX. We also analyzed use of medications for osteoporosis. Associations between the selected variables and PJK with VF were assessed by the Mann-Whitney, Fishers exact, and Wilcoxon signed-rank tests, and Kaplan-Meier analysis, as indicated. RESULTS: Forty patients (31.5%) developed PJK with VF postoperatively,73% of them within 6 months of surgery. Statistical analysis of the selected variables found that only a preoperative estimate by FRAX of a > 15% risk of MOF within 10 years, pelvic tilt > 30° at first standing postoperatively and lower instrumented level (fusion terminating at the pelvis) were significantly associated with development of PJK with VF. CONCLUSION: Preoperative assessment of severity of osteoporosis using FRAX provides an accurate estimate of risk of postoperative PJK with VF after surgery for adult spinal deformity.

Pre-existing vertebral fracture is a risk factor for postoperative proximal junctional fracture after adult spinal deformity surgery: A propensity score-matched analysis.

BACKGROUND: Corrective surgery for adult spinal deformity has recently been increasingly performed because of aging populations and advances in minimally invasive surgery. Low bone mineral density is a major contributor to proximal junctional kyphosis after spinal long fusion. Assessment for low bone mineral density ideally involves both dual energy X-ray absorptiometry and identification of pre-existing vertebral fractures, the latter, requiring only standard equipment, being performed more frequently. We therefore aimed to examine the impact of pre-existing vertebral fractures on the incidence of type 2 proximal junctional kyphosis, including proximal junctional fracture and failure, after corrective surgery for adult spinal deformity. METHODS: We performed a retrospective, single institution study of 106 women aged over 50 years who had undergone corrective long spinal fusion for severely symptomatic spinal deformity from 2014 to 2017. We allocated them to three groups (with and without pre-existing vertebral fractures and with severe [Grades 2-3 according to Genant et al.'s classification] preexisting vertebral fractures) and used propensity score matching to minimize bias. The primary outcome was postoperative proximal junctional fracture and the secondary outcome proximal junctional kyphosis/failure. RESULTS: The primary and secondary endpoints were achieved significantly more often in the 28 patients with than in the 78 without preexisting vertebral fractures (total 41). The former group was also significantly older and had greater pelvic tilt and fewer fused segments than those without vertebral fractures. After propensity score matching, the incidences of the endpoints did not differ with pre-existing vertebral fracture status; however, patients with severe vertebral fractures more frequently had proximal junctional fractures postoperatively. Postoperative improvements in health-related quality of life scores did not differ with pre-existing vertebral fracture status. CONCLUSIONS: Severe pre-existing vertebral fractures are a risk factor for proximal junctional fracture after correction of adult spinal deformity.