Acute versus chronic vertebral compression fractures treated with kyphoplasty: early results

Abstract

Background context

Kyphoplasty, a minimally invasive technique for fracture reduction and stabilization, has been shown to reduce pain and restore vertebral body height in patients with vertebral compression fractures (VCFs). Analyses comparing treatment outcomes of acute versus chronic VCFs have not yet been reported.

Purpose

To assess whether kyphoplasty results in better clinical outcome and fracture reduction in patients with either acute or chronic VCFs.

Study design

A prospective, consecutive cohort study of patients who underwent kyphoplasty between March 2000 and December 2001 to treat osteoporotic VCFs that were either less than 10 weeks old (acute) or more than 4 months old (chronic). Fifteen subacute fractures (treated 10 to 16 weeks after fracture) were excluded from analyses.

Patient sample

Eighty-six VCFs in 47 patients (35 female and 12 male) were treated during 55 kyphoplasty procedures. Mean patient age was 74 years (range, 47 to 91).

Methods

Clinical outcomes were determined by comparison of preoperative and postoperative data from patient-reported indexes (pain assessment, pain medication usage and Oswestry Disability Index for Back Pain). Radiographs were assessed as to percent vertebral collapse, vertebral height restoration and local kyphosis correction.

Results

By 2 weeks after surgery, 90% of acute and 87% of chronic fractures were associated with pain relief. Narcotic usage decreased and Oswestry scores improved in almost all patients. Mean vertebral body height significantly improved after kyphoplasty (acute: 58% to 86% of estimated normal vertebral height, p<.001; chronic: 56% to 79% of estimated normal vertebral height, p<.001). Restoration to 89% or greater estimated normal vertebral height was achieved in 60% of acute fractures and 26% of chronic fractures. In addition, more acute fractures were reducible (greater than 80% restoration of height lost) compared with chronic fractures (p = .01). After kyphoplasty, less than 10% correction of height lost occurred in 8% of acute fractures and 20% of chronic fractures. Local kyphosis significantly improved after kyphoplasty (mean local Cobb angle: acute, 15 to 8 degrees, p<.001; chronic, 15 to 10 degrees, p<.001).

Conclusion

Fracture reduction was best achieved in acute fractures. Symptomatic chronic fractures may also remain candidates for kyphoplasty because pain relief and improvement in patient function are reliable and some kyphosis correction can still be achieved in many of these patients.

Introduction

More than 1.5 million osteoporotic fractures occur in the United States each year, and the direct hospital and nursing home cost continues to increase from $17 billion in 2001 [1]. Approximately 700,000 of these osteoporotic fractures affect vertebrae [1]. Whereas both men and women are susceptible to the effects of osteoporosis, vertebral compression fractures (VCFs) have been estimated to affect 25% of women over age 50 years and 40% of women over age 80 years [2].

VCFs are associated with increased mortality and morbidity, including chronic pain, impaired physical function and decreased quality of life [3], [4], [5], [6]. For example, a 7% reduction in timed forced expiratory volume (FEV₁) occurs with each thoracic-level fracture, and a decrease in pulmonary function is associated with both thoracic and lumbar fractures [7]. Patients who sustain one VCF are at a fivefold increased risk of sustaining additional fractures [8], [9], [10]. In a large prospective study, women over 65 years old with prevalent VCFs had a 23% increase in mortality compared with age-matched controls, and the mortality increased with the number of prevalent VCFs [11]. In addition, another study determined that 5 years after patients were diagnosed with VCFs, the observed survival rate was 61%, which was worse than the 76% expected survival rate [12].

Symptomatic VCFs may fail to respond to conservative treatment options, such as bed rest, analgesics and bracing. However, a minimally invasive technique for fracture reduction and stabilization (kyphoplasty) has recently been described as an alternative to medical therapy and open surgery [13], [14], [15]. Pain relief and vertebral height restoration in acute fractures have been reported with kyphoplasty [14], [16], [17]. We further analyze our data by fracture age in an attempt to refine the patient selection and treatment process, because the ideal treatment regimen has not been determined for patients with symptomatic vertebral compression fractures that do not respond to medical therapy. This is a prospective study to assess whether kyphoplasty patients with painful, acute fractures had better fracture correction and clinical outcome after surgery than kyphoplasty patients with painful chronic compression fractures.