Survival Rate and Risk Factor Analysis in Patients Who Experience a New Fracture after Kyphoplasty
Study Design: Retrospective study.
Objectives: To evaluate the factors related to the incidence of a new fracture in an adjacent vertebra after kyphoplasty for single vertebral body fracture due to osteoporosis and to assess the impact of such factors on patients’ survival rate.
Summary of Literature Review: It is controversial whether fracture of an adjacent vertebra after kyphoplasty is due to the natural course of osteoporosis or as a complication of kyphoplasty.
Materials and Methods: From December 2006 to December 2016, among 490 cases of kyphoplasty for single vertebral body fracture due to osteoporosis, 153 cases were analyzed retrospectively. The survival rate was analyzed based on age, gender, body mass index (BMI), fracture level, leakage of cement, amount of cement, compression rate, recovery rate, bone density, osteoporotic medication rate and compliance, existence of a compression fracture, hypertension, diabetes, and smoking habit. The average follow-up duration was 15.1 months (range, 1 month to 8 years and 8 months) and the mean age was 74.4 years (range, 54-93 years).
Results: A new fracture in an adjacent vertebral body occurred in 27 cases (17.3%). The 1-year survival rate was 82.6%, the 2-year survival rate was 72.5%, and the 6-year survival rate was 53.7%. The survival rate was significantly higher in patients younger than 75 years (p=0.0495). The survival rate was also significantly higher in patients with a preoperative vertebral bone density greater than −3.7 and hip bone density greater than −2.2 (p<0.0001, p=0.0114). The survival rate was significantly higher in patients with a BMI greater than 18.1 kg/m2 at the time of surgery (p=0.0014). Furthermore, the survival rate was significantly higher in patients with a postoperative recovery of vertebral height of 14% or less (p=0.0031). In addition, the survival rate was higher in patients without a compression fracture before surgery (p=0.0297). In multiple factor analysis, vertebral bone density (p=0.0049) and age (p=0.0408) were identified as statistically significant factors.
Conclusions: The survival rate was significantly lower at 1, 2, and 6 years in patients with an adjacent vertebral fracture. The most crucial factors affecting the survival rate were age and vertebral bone density.