Radiology of Osteoporosis

The radiologist has a number of roles not only in diagnosing but also in treating osteoporosis. Radiologists diagnose fragility fractures with all imaging modalities, which includes magnetic resonance imaging (MRI) demonstrating radiologically occult insufficiency fractures, but also lateral chest radiographs showing asymptomatic vertebral fractures. In particular MRI fragility fractures may have a nonspecific appearance and the radiologists needs to be familiar with the typical locations and findings, to differentiate these fractures from neoplastic lesions. It should be noted that radiologists do not simply need to diagnose fractures related to osteoporosis but also to diagnose those fractures which are complications of osteoporosis related pharmacotherapy. In addition to using standard radiological techniques radiologists also use dual-energy x-ray absorptiometry (DXA) and quantitative computed tomography (QCT) to quantitatively assess bone mineral density for diagnosing osteoporosis or osteopenia as well as to monitor therapy. DXA measurements of the femoral neck are also used to calculate osteoporotic fracture risk based on the Fracture Risk Assessment Tool (FRAX) score, which is universally available. Some of the new technologies such as high-resolution peripheral computed tomography (HR-pQCT) and MR spectroscopy allow assessment of bone architecture and bone marrow composition to characterize fracture risk. Finally radiologists are also involved in the therapy of osteoporotic fractures by using vertebroplasty, kyphoplasty, and sacroplasty. This review article will focus on standard techniques and new concepts in diagnosing and managing osteoporosis.

Osteoporotic Hip and Spine Fractures: A Current Review

Hip and spine fractures represent just a portion of the burden of osteoporosis; however, these fractures require treatment and often represent a major change in lifestyle for the patient and their family. The orthopedic surgeon plays a crucial role, not only in the treatment of these injuries but also providing guidance in prevention of future osteoporotic fractures. This review provides a brief epidemiology of the fractures, details the surgical techniques, and outlines the current treatment guidelines for orthopedic surgeons.

Two-year results of a randomized placebo-controlled trial of vertebroplasty for acute osteoporotic vertebral fractures

We previously reported the results of a randomized controlled trial that found no benefit of vertebroplasty over a sham procedure for acute osteoporotic vertebral fractures up to 6 months. We report here the 12-month and 24-month clinical outcomes of this trial. Eligible participants (n = 78) were randomly assigned to receive either vertebroplasty (n = 38) or a sham procedure (n = 40). Randomization was stratified by treatment center, sex, and symptom duration (<6 weeks or ≥6 weeks). Participants, investigators (except the treating radiologists), and outcome assessors were blinded to group assignments. Enrolment occurred between April 2004 and October 2008 with follow-up completed October 2010. The primary outcome was overall pain measured on a scale of 0 (no pain) to 10 (maximal imaginable pain). Secondary outcomes included pain at rest and at night, disability, quality of life, perceived recovery, and adverse events, including incident clinically apparent vertebral fractures. At 12 and 24 months, complete data were available for 67 (86%) and 57 (73%) participants, respectively. At 12 months participants in the active group improved by 2.4 ± 2.7 (mean ± SD) units in overall pain compared with 1.9 ± 2.8 units in the sham group, adjusted between-group mean difference (MD) 0.3 (95% confidence interval [CI], –0.9 to 1.5), whereas at 24 months participants in the active group had improved by 3.0 ± 3.1 units compared with 1.9 ± 3.0 units in the sham group, MD 1.1 (95% CI, –0.3 to 2.4). No significant between-group differences were observed for any of the secondary efficacy outcomes at 12 or 24 months. There were no between-group differences in incident clinical vertebral fractures up to 24 months (active: n = 14, sham: n = 13), although the study had inadequate power for this outcome. These results provide further evidence that the use of this treatment in routine care is unsupported.

Impact of sham-controlled vertebroplasty trials on referral patterns at two academic medical centers

Debate persists regarding the merit of vertebroplasty following publication of blinded vertebroplasty trials in 2009, one of which was the Investigational Vertebroplasty Efficacy and Safety Trial (INVEST). This study was performed to determine whether referring physicians at two academic medical centers were aware of the trial results and to assess if this awareness prompted a change in their treatment of osteoporotic fractures. E-mail surveys were distributed to physicians within the Mayo Clinic and Baylor Health Care System (BHCS). Of 1390 surveys sent, 194 (14%) were returned. Results showed that 92 of 158 respondents (58%) reported familiarity with INVEST; 66 of 92 (72%) agreed that INVEST changed their understanding of vertebroplasty efficacy; and 64 of 92 (70%) agreed that INVEST diminished their enthusiasm to refer patients for vertebroplasty. However, 105 of 159 respondents (66%) felt vertebroplasty was an effective procedure in appropriate patients. Mayo physicians were more likely than BHCS physicians to be aware of INVEST (73% vs 67%, P < .0001), respond that INVEST changed their understanding of the appropriate treatment for osteoporotic compression fractures (79% vs 57%, P = 0.026), view vertebroplasty less favorably (45% vs 21%, P = 0.005), and treat osteoporotic compression fractures with medical therapy/pain management alone (73% vs 48%, P = 0.003). INVEST changed referring physicians' understanding of the role of vertebroplasty and diminished their willingness to refer osteoporotic compression fracture patients; the impact varied by location.

Balloon kyphoplasty compared to vertebroplasty and nonsurgical management in patients hospitalised with acute osteoporotic vertebral compression fracture: a UK cost-effectiveness analysis

The purpose of the study was to estimate the cost-effectiveness of balloon kyphoplasty compared to nonsurgical management and vertebroplasty for the treatment of hospitalised osteoporotic vertebral compression fractures in the UK. A cost-effectiveness model was constructed and used for analysis. Balloon kyphoplasty may be cost-effective compared to relevant alternatives.

INTRODUCTION

The objective of this study was to estimate the cost-effectiveness of balloon kyphoplasty (BKP) for the treatment of patients hospitalised with acute osteoporotic vertebral compression fracture (OVCF) compared to percutaneous vertebroplasty (PVP) and nonsurgical management (NSM) in the UK.

METHODS

A Markov simulation model was developed to evaluate treatment with BKP, NSM and PVP in patients with symptomatic OVCF. Data on health-related quality of life (HRQoL) with acute OVCF were derived from the FREE and VERTOS II randomised clinical trials (RCTs) and normalised to the NSM arm in the FREE trial. Estimated differences in mortality among the treatments and costs for NSM were obtained from the literature whereas procedure costs for BKP and PVP were obtained from three National Health Service hospitals. It was assumed that BKP and PVP reduced hospital length of stay by 6 days compared to NSM.

RESULTS

The incremental cost-effectiveness ratio was estimated at Great Britain Pound Sterling (GBP) 2,706 per quality-adjusted life year (QALY) and GBP 15,982 per QALY compared to NSM and PVP, respectively. Sensitivity analysis showed that the cost-effectiveness of BKP vs. NSM was robust when mortality and HRQoL benefits with BKP were varied. The cost-effectiveness of BKP compared to PVP was particularly sensitive to changes in the mortality benefit.

CONCLUSION

BKP may be a cost-effective strategy for the treatment of patients hospitalised with acute OVCF in the UK compared to NSM and PVP. Additional RCT data on the benefits of BKP and PVP compared to simulated sham surgery and further data on the mortality benefits with BKP compared to NSM and PVP would reduce uncertainty.

Optimal intravertebral cement volume in percutaneous vertebroplasty for painful osteoporotic vertebral compression fractures

STUDY DESIGN

A prospective follow-up study.

OBJECTIVE

Assessment of the relation between accomplishment of pain relief through percutaneous vertebroplasty (PVP) in painful osteoporotic vertebral compression fractures (OVCFs) and the cemented fraction of the vertebral body and subsequent determination of the optimal intravertebral cement volume.

SUMMARY OF BACKGROUND DATA

The mechanism of pain relief of PVP as a treatment modality for painful OVCFs remains unclear. Generally, benefit of PVP is thought to result from stabilization of micromovements and collapse of the fractured vertebral body. However, studies indicating a relation between intravertebral cement volume and pain relief are lacking and an optimal value of the intravertebral cement volume is unknown.

METHODS

One hunderd six patients who received PVP for 196 painful OVCFs were prospectively followed on back pain (score 0-10) and occurrence of new OVCFs during the first postoperative year. Patients were classified as responders (average postoperative back pain ≤ 6) and nonresponders (average postoperative back pain >6). The cemented fraction of the vertebral body was determined using volumetric analysis of the postoperative CT scan of the treated levels. Analysis was performed using receiver-operating characteristic (ROC) analysis and multivariable regression techniques.

RESULTS

Twenty-nine patients (27.3%) were found to be nonresponders. Mean intravertebral cement volume in all 196 treated OVCFs was 3.94 mL (SD = 1.89, range 0.13-10.8). The mean cemented vertebral body fraction was significantly lower in nonresponders (0.15 vs. 0.21, P = 0.002). The ROC area-under-curve of the cemented fraction as a predictor of accomplishment of pain relief was 0.67 (95% CI: 0.57-0.78, P = 0.006). In subgroups without specific influential factors (new OVCFs, intravertebral clefts), significantly stronger associations were found. A vertebral body fraction of 24% was identified as the optimal fraction to be cemented. This fraction corresponded to a 93% to 100% specificity for accomplishment of pain relief (i.e., few to no cases without pain relief in the presence of adequate cementing) without being significantly associated with a higher risk of occurrence of cement leakage or new OVCFs. Corresponding values for the recommended (optimal) intravertebral cement volume were provided based on its governing characteristics (fracture level, fracture severity, and patient's sex).

CONCLUSION

An optimal intravertebral cement volume was identified for accomplishment of pain relief through PVP in painful OVCFs. Appropriate thresholds were provided to guide the operator.

Percutaneous vertebroplasty for subacute and chronic painful osteoporotic vertebral compression fractures can safely be undertaken in the first year after the onset of symptoms

The optimal timing of percutaneous vertebroplasty as treatment for painful osteoporotic vertebral compression fractures (OVCFs) is still unclear. With the position of vertebroplasty having been challenged by recent placebo-controlled studies, appropriate timing gains importance. We investigated the relationship between the onset of symptoms - the time from fracture - and the efficacy of vertebroplasty in 115 patients with 216 painful subacute or chronic OVCFs (mean time from fracture 6.0 months (sd 2.9)). These patients were followed prospectively in the first post-operative year to assess the level of back pain and by means of health-related quality of life (HRQoL). We also investigated whether greater time from fracture resulted in a higher risk of complications or worse pre-operative condition, increased vertebral deformity or the development of nonunion of the fracture as demonstrated by the presence of an intravertebral cleft. It was found that there was an immediate and sustainable improvement in the level of back pain and HRQoL after vertebroplasty, which was independent of the time from fracture. Greater time from fracture was associated with neither worse pre-operative conditions nor increased vertebral deformity, nor with the presence of an intravertebral cleft. We conclude that vertebroplasty can be safely undertaken at an appropriate moment between two and 12 months following the onset of symptoms of an OVCF.

Effectiveness of vertebroplasty using individual patient data from two randomised placebo controlled trials: meta-analysis

OBJECTIVE

To determine whether vertebroplasty is more effective than placebo for patients with pain of recent onset (≤ 6 weeks) or severe pain (score ≥ 8 on 0-10 numerical rating scale).

DESIGN

Meta-analysis of combined individual patient level data.

SETTING

Two multicentred randomised controlled trials of vertebroplasty; one based in Australia, the other in the United States.

PARTICIPANTS

209 participants (Australian trial n = 78, US trial n = 131) with at least one radiographically confirmed vertebral compression fracture. 57 (27%) participants had pain of recent onset (vertebroplasty n = 25, placebo n = 32) and 99 (47%) had severe pain at baseline (vertebroplasty n = 50, placebo n = 49).

INTERVENTION

Percutaneous vertebroplasty versus a placebo procedure.

MAIN OUTCOME MEASURE

Scores for pain (0-10 scale) and function (modified, 23 item Roland-Morris disability questionnaire) at one month.

RESULTS

For participants with pain of recent onset, between group differences in mean change scores at one month for pain and disability were 0.1 (95% confidence interval -1.4 to 1.6) and 0.2 (-3.0 to 3.4), respectively. For participants with severe pain at baseline, between group differences for pain and disability scores at one month were 0.3 (-0.8 to 1.5) and 1.4 (-1.2 to 3.9), respectively. At one month those in the vertebroplasty group were more likely to be using opioids.

CONCLUSIONS

Individual patient data meta-analysis from two blinded trials of vertebroplasty, powered for subgroup analyses, failed to show an advantage of vertebroplasty over placebo for participants with recent onset fracture or severe pain. These results do not support the hypothesis that selected subgroups would benefit from vertebroplasty.

Comparative hospital economics and patient presentation: vertebroplasty and kyphoplasty for the treatment of vertebral compression fracture

BACKGROUND AND PURPOSE

Previous studies evaluating vertebral augmentation procedure costs have not made detailed comparisons between vertebroplasty and kyphoplasty. Our study contrasts hospital costs for vertebroplasty versus kyphoplasty for the treatment of vertebral compression fractures in routine clinical practice in the United States.

MATERIALS AND METHODS

This retrospective cohort study analyzed 2007-2008 hospital discharge and billing records from the Premier Perspective data base. The primary outcome variable, differences in total hospital cost between vertebroplasty and kyphoplasty, was assessed by using analysis of covariance.

RESULTS

Three thousand six hundred seventeen patients received vertebroplasty (64% inpatient, 36% outpatient), and 8118 received kyphoplasty (54% inpatient, 46% outpatient). Approximately 75% were women, and most were white. Mean total unadjusted inpatient costs were $9837 for vertebroplasty versus $13 187 for kyphoplasty (P < .0001). Outpatient vertebroplasty costs were $3319 versus $8100 for kyphoplasty (P < .0001). Lower vertebroplasty costs were largely due to differences in hospital supply and OR. Mean vertebroplasty OR costs were $73.60 (anesthesia), $112.06 (recovery room), and $990.12 (surgery) versus $172.16 (anesthesia), $257.47 (recovery room), and $1,471.49 (surgery) with kyphoplasty. Adjustments for age, sex, admission status, and disease severity accentuated the differences. Mean adjusted inpatient costs were $11 386 for vertebroplasty versus $16 182 for kyphoplasty (P < .0001), and outpatient costs were $2997 for vertebroplasty versus $7010 for kyphoplasty (P < .0001). After adjustments for the same covariates, length-of-stay differences were no longer evident (P = .4945).

CONCLUSIONS

Performing vertebroplasty versus kyphoplasty reduces hospital costs by nearly $5000 for inpatient procedures and by more than $4000 for outpatient procedures.

Musculoskeletal imaging: current and future trends

Advances in imaging technology and the increasing role of interventional procedures in musculoskeletal imaging have continued to stimulate research over recent years. This review summarises some recent articles on musculoskeletal radiology topics and looks forward to potential future developments in this exciting sub-speciality.