1. 2022;25;E725-E732Predictive Factors for Adjacent Vertebral Fractures After Percutaneous Kyphoplasty in Patients With Osteoporotic Vertebral Compression Fracture
   Retrospective Study
   Gu Yue, MD, Sun Jinpeng, MD, Qin Hu, MD, Chen Xingmei, MD, Wang Biao, MD, Wu Tao, MD, and Liu Jun, MD.

BACKGROUND: Adjacent vertebral fracture (AVF) seemed to be a frequent and severe complication in osteoporotic vertebral compression fracture (OVCF) patients receiving percutaneous vertebroplasty  or percutaneous kyphoplasty (PKP), resulting in poor long-term outcome and recurrence of pain-related symptoms. Nonetheless, its mechanism remains unclear.

OBJECTIVES: To investigate the potential predictor of AVF after PKP and figure out whether the intervertebral disc plays a role during the process of AVF.

STUDY DESIGN: Retrospective study.

SETTING: Department of Orthopedic, an affiliated hospital of a medical university.

METHODS: Clinical data of OVCF patients receiving PKP were reviewed in our hospital from January 2016 to December 2020. Four hundred and forty-five patients were recruited who met the abovementioned criteria in this study. The clinical data, including age, gender, bone mineral density (BMD), vertebral height, vertebral kyphosis angle, cement volume, cement distribution, as well as adjacent disc degeneration extent, were recorded for each patient. Independent-sample t tests and chi-squared tests were performed to compare these indexes. Bivariate correlation tests and multiple linear regression analyses were performed among potential predictors. Receiver operator characteristic (ROC) analysis and Kaplan-Meier plotter were applied to evaluate the diagnostic efficiency of parameters for predicting the occurrence of AVF.

RESULTS: Patients in both groups gained obvious improvements in symptomatic and radiographic indexes after first PKP. Statistically significant difference (P < 0.05) was only found between 2 groups with respect to BMD, kyphosis angle at last follow-up before second PKP, cement distribution, and disc degeneration grade. The ROC analysis showed that BMD <= -3.45 was weakly associated with AVF after PKP (sensitivity, 33.3%; specificity, 40.4%; area under curve, 0.324, P = 0.000). In addition, kyphosis angle at last follow-up before second surgery >= 15.5° was highly predictive of AVF after PKP (sensitivity, 92.2%; specificity, 24.6%; area under curve, 0.569, P = 0.109). Statistically significant difference of AVF incidence amongst patients with different cement distribution (P = 0.018) and similar trend was also found amongst patients with different disc degeneration (P = 0.000). Statistically significant difference was noted in terms of disc degeneration grade between 2 adjacent discs in AVF group.

LIMITATIONS: The main limitation is the retrospective nature of this study.

CONCLUSIONS: The risk of AVF should be focused, especially when OVCF patients with the following predictors: (1) BMD < -3.45; (2) kyphosis angle at last follow-up > 15.5°; (3) I or II cement distribution; and (4) IV or V disc degeneration. More prophylactic treatment should be prescribed for these patients to avoid the occurrence of AVF.

KEY WORDS: Predictive factors, adjacent vertebral fracture, percutaneous kyphoplasty, osteoporotic vertebral compression fracture