Elsevier

World Neurosurgery

Volume 106, October 2017, Pages 736-745
World Neurosurgery

Original Article
Spinal Instability Predictive Scoring System for Subsequent Fracture After Bone Cement Augmentation in Patients with Osteoporotic Vertebral Compression Fracture

https://doi.org/10.1016/j.wneu.2017.07.049Get rights and content

Objective

Bone cement augmentation procedures (vertebroplasty and kyphoplasty) are the primary treatments for osteoporotic vertebral compression fracture (VCF). However, these procedures are associated with various problems resulting in subsequent fracture. The purpose of this study was to evaluate the spinal instability factors related to subsequent fracture after vertebral augmentation procedures.

Methods

We retrospectively reviewed patients who underwent augmentation procedures for osteoporotic VCF. Between May 2011 and November 2014, 285 patients (vertebroplasty, n = 231; kyphoplasty, n = 54) were enrolled. Subsequent fractures were classified into 4 types based on the fracture patterns: 1) no subsequent fracture, 2) neofracture, 3) hammer fracture (new vertebral fractures involving another vertebra without a definitive history of trauma), and 4) kyphotic compression fracture. We analyzed subsequent fracture patterns and their occurrence rates according to factors that may induce subsequent fracture and developed a predictive scoring system with respect to the hammer fracture occurrence rate.

We classified all cases into 4 groups (A,B,C,D) according to Spinal Instability Predictive Scoring System score. Groups A, B, C, and D were defined by total scores of 0∼5, 6∼10, 11∼15, and 16∼20, respectively.

Results

The subsequent fracture types for vertebroplasty were as follows: no subsequent fracture (n = 112; 48.28%); hammer fracture (n = 65; 28.02%); neofracture (n = 35; 15.09%); and kyphotic compression fracture (n = 19; 8.19%). According to the total scores, the occurrence rate of subsequent hammer fracture (no subsequent fracture, hammer fracture, neofracture, and kyphotic compression fracture) were as follows: group A (84.21%, 0%, 10.52%, and 5.26%), group B (64.58%, 10.45%, 12.5%, and 12.5%), group C (39.39%, 33.3%, 15.15%, and 12.12%), and group D (11.67%, 63.3%, 21.67%, and 3.33%).

Conclusions

Predictive scores can be calculated and used to predict the possibility of subsequent fracture according to scores. Group D showed the highest predictive scores and will need more preventative treatment.

Introduction

Because the average life span has become increasingly prolonged worldwide, the percentage of the population prone to age-related osteoporotic vertebral compression fracture (VCF) has also been increasing. Recently, percutaneous augmentation procedures, which are based on the subcutaneous injection of polymethylmethacrylate, have been the therapeutic treatment of choice for VCF to relieve pain safely and effectively.1, 2, 3

Augmentation procedures, such as vertebroplasty (VP) and kyphoplasty (KP), have become the primary treatments of choices for osteoporotic VCF. Patients typically demonstrate rapid and durable pain relief and often regain lost function.4, 5 However, despite the demonstrated benefit, recent reports indicate that VP also increases the fracture morbidity through inducing or facilitating subsequent vertebral fractures.2, 6

In a retrospective study of 432 patients who underwent VP, Trout et al.7 found that 86 patients (19.9%) developed 186 new fractures and that 77 of these new fractures (41.1%) were in vertebrae adjacent to treated vertebrae. Other studies have suggested this problem is caused by changes in the load on adjacent vertebrae after VP, and have evaluated the relations between various risk factors, such as age, bone mineral density (BMD), and the characteristics and locations of these fractures.4, 8 Investigators have attempted to explore this issue through both clinical and biomechanical studies. The present study was undertaken to establish the relationships between new subsequent fracture development and different factors such as fracture site, vertebral augmentation level, BMD, vertebral height, vertebral kyphotic angle, and spinal column kyphotic angle. In addition, we used the predictive scoring system for predicting subsequent fracture and classified patients into several groups according to the scoring of the risk factors.

The study purpose was to evaluate the spinal instability factors related to subsequent fracture after vertebral augmentation procedures.

Section snippets

Patients

Between May 2011 and November 2014, we performed percutaneous vertebral bone cement augmentation procedures in 734 patients (812 vertebral bodies). We retrospectively reviewed 659 patients with VCF who were treated with vertebral augmentation (VP or KP). At the initial vertebral bone cement augmentation, 659 patients had a single vertebral fracture; patients with multiple vertebral fractures were excluded to simplify the analysis. A total of 285 patients (VP, n = 231; KP, n = 54) were

Results

A total of 285 patients (VP, n = 231; KP, n = 54) were enrolled in this study.

There were 53 men (VP, n = 39; KP, n = 14) and 233 women (VP, n = 193; KP, n = 40). The mean age was 73 years (range, 49–93 years; VP, 74 years; KP, 72.46 years; P = 0.539), and the mean follow-up duration was 35.5 months (range, 6–75 months). Five patients died of medical disease after 1 year of follow-up (mean survival, 32 months). The average BMD (T score) was –3.22 (VP, –3.07; KP, –3.16; P= 0.632). The L1 (n = 80)

Discussion

Osteoporotic VCF has recently become common disease in older adults and can manifest as severe pain, functional deterioration, and limited mobility. Conventional treatments (e.g., bed rest, bracing, physical therapy) can result in frequent side effects. Furthermore, osteoporotic VCFs can cause serious complications when patients undergo surgery, such as vertebral reconstruction or fusion under general anesthesia. Therefore, bone cement augmentation (e.g., percutaneous VP and KP) is considered

Conclusions

Biomechanical instability accompanied by compression fracture may play an important role in subsequent fracture after bone cement augmentation for osteoporotic VCF. According to the corrected SIPS, group D had a high predictive score. If the corrected SIPS score is high, the patients have a greater chance for subsequent fracture. Therefore, more attention must be provided to such patients; indeed, providing education regarding strict bed rest, spinal bracing, KP, booster vertebral augmentation,

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    Conflict of interest statement: The authors declare that the article content was composed in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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