Kyphoplasty: An Assessment of a New Technology
==============================================

* H.J. Cloft
* M.E. Jensen

## Abstract

**SUMMARY:** Kyphoplasty is a new procedure for the treatment of vertebral compression fractures that is being performed with increasing frequency. Representing the Technology Assessment Committee of the American Society of Interventional and Therapeutic Neuroradiology, we present a review of the available information regarding this new technology.

Osteoporosis is a widespread public health problem in the United States. The Surgeon General of the United States has recently called special attention to the importance of osteoporosis to Americans in an extensive report (*Bone Health and Osteoporosis: A Report of the Surgeon General)*.1 Vertebral body compression fractures are among the most common complications of osteoporosis. The lifetime risk of osteoporotic spine fracture in white women is 15.6%.2 Each year, more than 700,000 vertebral body fractures secondary to osteoporosis are diagnosed in the United States, resulting in 115,000 hospital admissions.3 The major consequences of osteoporotic compression fractures are back pain, kyphosis, and height loss.

Percutaneous vertebroplasty was developed to treat pain caused by painful vertebral fractures. The technique was initially reported in 1987 as a treatment of vertebral hemangiomas,4 but over time it has become more widely used for osteoporotic compression fracture treatment.5–13 The vertebroplasty procedure consists of fluoroscopically guided percutaneous placement of a needle into the affected vertebral body and injection of radiopaque polymethylmethacrylate cement. The mechanism of pain relief is uncertain, but it may be due to immobilization of the fracture fragments by the injected cement.

As vertebroplasty utilization was becoming widespread, kyphoplasty was introduced as an alternative approach. Kyphoplasty entails inflation of a percutaneously delivered balloon in the vertebral body, followed by the percutaneous injection of bone cement into the cavity created by the balloon. Kyphoplasty is quite similar to vertebroplasty, differing only in the use of the balloon. Indeed, kyphoplasty has been referred to as “balloon-assisted kyphoplasty.”14 The balloon is intended to restore the vertebral body height while creating a cavity to be filled with bone cement.15,16 The balloon, the KyphX Inflatable Bone Tamp, is manufactured by Kyphon (Sunnyvale, Calif), and has been approved by the United States Food and Drug Administration for use as a bone tamp for the reduction of fractures, and/or the creation of a void in cancellous bone.

Percutaneous vertebroplasty and kyphoplasty both are now widely used to treat osteoporotic compression fractures. In the absence of a prospective clinical trial directly comparing the efficacy and safety of these procedures, the decision to offer patients one procedure instead of the other is generally based on studies that do not directly compare the 2 procedures as well as physicians’ individual experience with the procedures. In this report, we review the literature and assess the application kyphoplasty for the treatment of vertebral compression fractures relative to vertebroplasty. We compare kyphoplasty to vertebroplasty with respect to 4 issues: 1) pain relief, 2) vertebral height restoration, 3) procedural complications, and 4) financial cost.

## Pain Relief

As treatments of painful vertebral fractures, vertebroplasty and kyphoplasty should primarily be evaluated for success in relieving pain. Both vertebroplasty5–7,10,11,13,17–26 and kyphoplasty16,26–40 have been reported to provide substantial pain relief to most patients. The mechanism of pain relief with vertebroplasty and kyphoplasty is not known with certainty, but it probably relates to immobilization of fracture fragments by the injected cement. The method of pain assessment has varied considerably and has included techniques such as narcotic pain medication usage,5,23,34,41 visual analog scale,6,7,13,20,22,24–27,29–36,39,40,42 patient activity level,5,7,29,31,41 Barthel index,13,42 McGill-Melzack pain scoring system,20 European Vertebral Osteoporosis Study score,30,40 Osteoporosis Quality of Life Questionnaire,21 Short Form-36,16,27 Musculoskeletal Outcomes Data Evaluation and Management Scale,11 Oswestry Disability Index,26,27,32,34,37 and the Roland-Morris Disability Survey.35 Patient selection also has varied considerably; most patients treated are afflicted with benign osteoporotic fractures, but a significant number have malignant fractures and hemangiomas. Without a direct comparison of vertebroplasty and kyphoplasty with a validated outcome measure in a prospective, randomized trial, it is not possible to know with certainty whether one procedure offers more pain relief than the other.

## Height Restoration

Through the use of a balloon, kyphoplasty is intended to provide restoration of vertebral body height. Recent publications have reported restoration of height of fractured vertebral bodies treated with kyphoplasty.15,16,35,38 The study by Lieberman et al16 used a method of measurement of height restoration that tends to yield height restoration numbers that are impressive at first glance (ie, percentage restoration of lost vertebral body height). They reported a 35% mean improvement in vertebral body height. The mean preprocedure height loss due to the fracture was reported to be 8.7 mm, so the mean height restoration with treatment would be 35% of that 8.7 mm. That amounts to a mean height restoration of 2.9 mm, which is approximately equal to one eighth of an inch. Rhyne et al35 reported anterior height restoration with kyphoplasty to be 4.6 mm, and Gaitanis et al32 reported it to be 4.3 mm, but Feltes et al29 reported a complete lack of height restoration.

Some recent reports suggest that vertebroplasty offers a degree of height restoration similar to that of kyphoplasty.43–46 Teng et al43 reported a height restoration of 27%, and Dublin45 reported an improvement of 49% with vertebroplasty, which compare favorably with the height restoration of 35% reported by Lieberman et al16 with kyphoplasty. Hiwatashi et al44 reported an increase in height of 2.7 mm with vertebroplasty, which is remarkably similar to the 2.9 mm in the series by Lieberman et al16 with kyphoplasty. McKiernan et al15 reported that height restoration occurred in 23 of 65 vertebral compression fractures treated with vertebroplasty. In the 23 cases with height restoration, the mean anterior height restoration was 8.4 mm,15 but the mean height restoration for the entire group of 65 patients treated would be 3.0 mm.

The term kyphoplasty implies treatment of kyphosis, and kyphosis is generally quantified as an angle. The mean improvement of kyphosis angle with kyphoplasty has been reported to be 3.4°–8.8°.26,32,35,36,39 The mean improvement in kyphosis angle with vertebroplasty is quite similar, reported to be 4.3°–6.4%.43,45–47 Some of the improvement in kyphosis after kyphoplasty and vertebroplasty might be the result of the improved posture that results from pain relief rather than a direct mechanical effect of the procedure.

Height restoration of a fractured vertebra after kyphoplasty or vertebroplasty may occur with fractures with particular characteristics. In one report, kyphoplasty yielded better height restoration in acute fractures (< 10 weeks old) than in chronic fractures (> 4 months old).34 The presence of an intravertebral cleft or cyst has been reported to correlate with the degree of height restoration after vertebroplasty.43,47,48

It is certainly conceivable that pain from vertebral body collapse is due at least in part to a malalignment of musculoskeletal structures that results from height loss. One might expect a trend toward more pain relief with patients who are treated with height restoration versus those whose treatment results in no height restoration, but such a trend remains unproved. Pain relief certainly can be achieved with vertebroplasty18 and kyphoplasty29 in the absence of significant height restoration, and McKiernan et al49 found no association between pain relief and height restoration after vertebroplasty. From the patient’s perspective, there might be some intrinsic value to height restoration. But patients with osteoporotic compression fractures are generally seeking pain relief and most would consider cosmetic height restoration to be only a small bonus. Restoring a few millimeters of height to a single vertebra probably has no effect on the patient’s apparent kyphosis or overall height loss and may have no clinical relevance.50 Of course, there are patients with many vertebral body fractures who have lost inches of overall height, but performance of extensive multilevel kyphoplasty or vertebroplasty at all levels would be necessary to restore even a single inch to their overall height. Subjecting these fragile patients to multilevel procedures simply for height gain might do more harm than good. Thus, any therapeutic benefit of height restoration remains entirely speculative. Height restoration will only be a relevant outcome variable if it correlates with pain relief or some other measurable improvement in the patient’s quality of life.

Despite lack of substantial height restoration in most cases, most patients report substantial pain relief with vertebroplasty and kyphoplasty. Patients treated with vertebroplasty and kyphoplasty are generally quite satisfied with their pain relief and rarely express disappointment in a lack of height restoration. Future developments in vertebral body compression fracture therapy may provide substantial height restoration. However, based on current evidence, neither kyphoplasty nor vertebroplasty reliably restores substantial vertebral body height in most patients, and the intrinsic value of vertebral body height restoration remains speculative. If the height restoration and kyphosis correction achieved with kyphoplasty are no better than that achieved with vertebroplasty, perhaps no benefit of the kyphoplasty balloon justifies the substantial added financial expense of kyphoplasty.

## Complications

Complications of both vertebroplasty and kyphoplasty are most commonly related to placement of hardware in an incorrect location or extrusion of cement outside of the fractured vertebra. Pulmonary embolism,51,52 infection,53 bleeding,54 and nerve or spinal cord compression by cement54,55 can all occur. Rib fractures are also known to happen as a result of pressure on the back and chest occurring during needle placement while the patient is prone.5 Complications resulting from improper needle placement or inattention to fluoroscopic patterns of cement distribution during injection are dependent on operator training and experience. Nonetheless, such complications will undoubtedly occur occasionally even with well-trained, experienced operators.

The overall symptomatic complication rate reported for vertebroplasty as a treatment of osteoporotic compression fractures is less than 1%–6%, consisting mostly of minor complications such as rib fractures and temporary radicular pain.5–7,25 Major complications, such as permanent neurologic injury or serious pulmonary embolism, are rare, occurring in less than 1% of cases.56

Little is published in the peer-reviewed literature regarding complications of kyphoplasty. Six major complications in 531 patients (1.1%) treated with kyphoplasty were reported in a multicenter collection of patients, 4 of which were neurologic complications.54 Majd et al38 reported 13 complications in 254 (5.1%) procedures. Nussbaum et al55 evaluated kyphoplasty and vertebroplasty complications reported to the United States Food and Drug administration and found a number of complications of kyphoplasty not reported elsewhere, including 5 cases of spinal canal intrusion associated with permanent neurologic deficit and 13 cases of spinal canal intrusion necessitating surgical decompression.

The issue of extrusion of cement outside of the vertebral body with vertebroplasty and kyphoplasty has received considerable attention. Cement extrusion with vertebroplasty has been reported to occur in 3% to 70% of cases, but frequency of cement leakage is much higher in cases with neoplastic involvement of the vertebra.5,11,22–24,57–61 Indeed, because of the unpredictability of the behavior of methylmethacrylate when injected into tumor tissue, treatment of vertebrae invaded by neoplasm can be expected to have a higher complication rate with both vertebroplasty and kyphoplasty. Therefore, one must be careful not to compare results from a series of patients treated for osteoporotic fractures to another series of patients treated for neoplastic vertebral involvement. In patients with osteoporotic compression fractures, extrusion of cement outside of the vertebra with vertebroplasty has been reported in 3% to 27% of treated vertebrae.5,11,22,24,37,61 The incidence of cement extrusion outside of bone occurring during kyphoplasty has been reported to be 8.6%–33%.16,31–33,35,36,62 A decrease in potential for cement extrusion with kyphoplasty has been suggested, because the cavity formed and more viscous cement result in a need for less injection pressure.28,54 Because cement extrusion outside of the vertebral body is usually asymptomatic with either vertebroplasty or kyphoplasty, it makes more sense to monitor and compare symptomatic complications rather than incidence of cement extrusion.

In addition to the short-term periprocedural risk of vertebroplasty and kyphoplasty, there may be an additional risk of new fracture development subsequent to the treatment. New fractures have been reported subsequent to vertebroplasty19,63,64 and kyphoplasty.32,36,65,66 Because new vertebral fractures can occur in osteoporotic patients simply due to disease progression rather than as a result of vertebroplasty or kyphoplasty,67,68 it is difficult to determine the added risk of fracture resulting from these procedures.

In general, both vertebroplasty and kyphoplasty are relatively safe procedures when performed by skilled operators. A prospective, randomized trial directly comparing outcomes of kyphoplasty and vertebroplasty would be necessary to accurately compare the relative safety of the 2 procedures.

## Economic Cost

The economic cost of kyphoplasty is another aspect of the procedure that has attracted attention. Vertebroplasty has generally been performed as an outpatient procedure with local anesthesia and conscious sedation,5,7,11,12,22,24,25,41–43,45 whereas kyphoplasty has generally been performed as an inpatient procedure and with general anesthesia.20,27,29,31–35,37 For kyphoplasty, balloons add considerable expense to the procedure. The cost of a KyphoPak kit (Kyphon) for a single-level vertebroplasty is $3423. Overall, kyphoplasty is approximately $6000 more expensive than vertebroplasty per vertebra treated.69 Because of additional equipment, anesthesia, and hospital costs, kyphoplasty is approximately 2.5 times more expensive than vertebroplasty.69

## Conclusions

Thus far, there is no proved advantage of kyphoplasty relative to vertebroplasty with regard to pain relief, vertebral height restoration, and complication rate. It is possible that both vertebroplasty and kyphoplasty are useful in the treatment of vertebral compression fractures and that certain subgroups of patients may derive more benefit from one particular procedure.70 Features that might affect choice of procedure include degree of compression deformity, age of the fracture, and the presence of neoplastic involvement. However, benefits of kyphoplasty relative to vertebroplasty in such subgroups currently remain undefined. With the considerable added financial expense of kyphoplasty, a significant clinical benefit over vertebroplasty would have to be proved to justify this expense. A convincing benefit to kyphoplasty relative to vertebroplasty can only be proved by comparing outcomes from both procedures in a prospective, randomized study. Such a trial, sponsored by Kyphon, is currently being planned. With large numbers of vertebroplasty and kyphoplasty being performed currently, it should be relatively simple to recruit patients into trials that look at the relative merits of the 2 procedures in well-defined patient populations.

## References

1.  Office of the Surgeon General. Bone Health and Osteoporosis: A Report of the Surgeon General. Washington, DC: United States Department of Health and Human Services;2004
    
    

2.  Cummings SR, Melton LJ. **Epidemiology and outcomes of osteoporotic fractures.** Lancet 2002;359:1761–67
    
    [CrossRef](http://www.ajnr.org/lookup/external-ref?access_num=10.1016/S0140-6736(02)08657-9&link_type=DOI) 
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=12049882&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 
    
    [Web of Science](http://www.ajnr.org/lookup/external-ref?access_num=000175740500030&link_type=ISI) 

3.  Riggs BL, Melton LJ, 3rd. **The worldwide problem of osteoporosis: insights afforded by epidemiology.** Bone 1995;17:505S–511S
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=8573428&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 

4.  Galibert P, Deramond H, Rosat P, et al. [**Preliminary note on the treatment of vertebral angioma by percutaneous acrylic vertebroplasty.**] Neurochirurgie 1987;33:166–68
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=3600949&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 
    
    [Web of Science](http://www.ajnr.org/lookup/external-ref?access_num=A1987H183900012&link_type=ISI) 

5.  Jensen ME, Evans AJ, Mathis JM, et al. **Percutaneous polymethylmethacrylate vertebroplasty in the treatment of osteoporotic vertebral body compression fractures: technical aspects.** AJNR Am J Neuroradiol 1997;18:1897–904
    
    [Abstract](http://www.ajnr.org/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6NDoiYWpuciI7czo1OiJyZXNpZCI7czoxMDoiMTgvMTAvMTg5NyI7czo0OiJhdG9tIjtzOjE5OiIvYWpuci8yOC8yLzIwMC5hdG9tIjt9czo4OiJmcmFnbWVudCI7czowOiIiO30=) 

6.  Barr JD, Barr MS, Lemley TJ, et al. **Percutaneous vertebroplasty for pain relief and spinal stabilization.** Spine 2000;25:923–28
    
    [CrossRef](http://www.ajnr.org/lookup/external-ref?access_num=10.1097/00007632-200004150-00005&link_type=DOI) 
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=10767803&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 
    
    [Web of Science](http://www.ajnr.org/lookup/external-ref?access_num=000086678400004&link_type=ISI) 

7.  Evans AJ, Jensen ME, Kip KE, et al. **Vertebral compression fractures: pain reduction and improvement in functional mobility after percutaneous polymethylmethacrylate vertebroplasty retrospective report of 245 cases.** Radiology 2003;226:366–72
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=12563127&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 
    
    [Web of Science](http://www.ajnr.org/lookup/external-ref?access_num=000180657000011&link_type=ISI) 

8.  Kallmes DF, Jensen ME. **Percutaneous vertebroplasty.** Radiology 2003;229:27–36
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=14519867&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 
    
    [Web of Science](http://www.ajnr.org/lookup/external-ref?access_num=000185424900009&link_type=ISI) 

9.  Mathis JM, Barr JD, Belkoff SM, et al. **Percutaneous vertebroplasty: a developing standard of care for vertebral compression fractures.** AJNR Am J Neuroradiol 2001;22:373–81
    
    [FREE Full Text](http://www.ajnr.org/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiRlVMTCI7czoxMToiam91cm5hbENvZGUiO3M6NDoiYWpuciI7czo1OiJyZXNpZCI7czo4OiIyMi8yLzM3MyI7czo0OiJhdG9tIjtzOjE5OiIvYWpuci8yOC8yLzIwMC5hdG9tIjt9czo4OiJmcmFnbWVudCI7czowOiIiO30=) 

10. Cortet B, Cotten A, Boutry N, et al. **Percutaneous vertebroplasty in the treatment of osteoporotic vertebral compression fractures: an open prospective study.** J Rheumatol 1999;26:2222–28
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=10529144&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 
    
    [Web of Science](http://www.ajnr.org/lookup/external-ref?access_num=000083014300029&link_type=ISI) 

11. Zoarski GH, Snow P, Olan WJ, et al. **Percutaneous vertebroplasty for osteoporotic compression fractures: quantitative prospective evaluation of long-term outcomes.** J Vasc Interv Radiol 2002;13:139–48
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=11830619&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 
    
    [Web of Science](http://www.ajnr.org/lookup/external-ref?access_num=000173835200003&link_type=ISI) 

12. Hodler J, Peck D, Gilula LA. **Midterm outcome after vertebroplasty: predictive value of technical and patient-related factors.** Radiology 2003;227:662–68
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=12702821&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 

13. Diamond TH, Bryant C, Browne L, et al. **Clinical outcomes after acute osteoporotic vertebral fractures: a 2-year non-randomised trial comparing percutaneous vertebroplasty with conservative therapy.** Med J Aust 2006;184:113–17
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=16460295&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 
    
    [Web of Science](http://www.ajnr.org/lookup/external-ref?access_num=000235790000005&link_type=ISI) 

14. Olan WJ. **Balloon-assisted vertebroplasty.** ASNR Spine Symposium 2002
    
    

15. McKiernan F, Faciszewski T, Jensen R. **Reporting height restoration in vertebral compression fractures.** Spine 2003;28:2517–21
    
    [CrossRef](http://www.ajnr.org/lookup/external-ref?access_num=10.1097/01.BRS.0000092424.29886.C9&link_type=DOI) 
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=14624087&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 

16. Lieberman IH, Dudeney S, Reinhardt MK, et al. **Initial outcome and efficacy of “kyphoplasty” in the treatment of painful osteoporotic vertebral compression fractures.** Spine 2001;26:1631–38
    
    [CrossRef](http://www.ajnr.org/lookup/external-ref?access_num=10.1097/00007632-200107150-00026&link_type=DOI) 
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=11464159&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 
    
    [Web of Science](http://www.ajnr.org/lookup/external-ref?access_num=000170065000021&link_type=ISI) 

17. McGraw JK, Lippert JA, Minkus KD, et al. **Prospective evaluation of pain relief in 100 patients undergoing percutaneous vertebroplasty: results and follow-up.** J Vasc Interv Radiol 2002;13:883–86
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=12354821&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 
    
    [Web of Science](http://www.ajnr.org/lookup/external-ref?access_num=000178392900003&link_type=ISI) 

18. O’Brien JP, Sims JT, Evans AJ. **Vertebroplasty in patients with severe vertebral compression fractures: a technical report.** AJNR Am J Neuroradiol 2000;21:1555–58
    
    [Abstract/FREE Full Text](http://www.ajnr.org/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6NDoiYWpuciI7czo1OiJyZXNpZCI7czo5OiIyMS84LzE1NTUiO3M6NDoiYXRvbSI7czoxOToiL2FqbnIvMjgvMi8yMDAuYXRvbSI7fXM6ODoiZnJhZ21lbnQiO3M6MDoiIjt9) 

19. Grados F, Depriester C, Cayrolle G, et al. **Long-term observations of vertebral osteoporotic fractures treated by percutaneous vertebroplasty.** Rheumatology (Oxford) 2000;39:1410–14
    
    

20. Legroux-Gerot I, Lormeau C, Boutry N, et al. **Long-term follow-up of vertebral osteoporotic fractures treated by percutaneous vertebroplasty.** Clin Rheumatol 2004;23:310–17
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=15293091&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 
    
    [Web of Science](http://www.ajnr.org/lookup/external-ref?access_num=000223023900005&link_type=ISI) 

21. McKiernan F, Faciszewski T, Jensen R. **Quality of life following vertebroplasty.** J Bone Joint Surg Am 2004;86:2600–06
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=15590842&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 

22. Heini PF, Walchli B, Berlemann U. **Percutaneous transpedicular vertebroplasty with PMMA: operative technique and early results. A prospective study for the treatment of osteoporotic compression fractures.** Eur Spine J 2000;9:445–50
    
    [CrossRef](http://www.ajnr.org/lookup/external-ref?access_num=10.1007/s005860000182&link_type=DOI) 
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=11057541&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 
    
    [Web of Science](http://www.ajnr.org/lookup/external-ref?access_num=000089900900014&link_type=ISI) 

23. Weill A, Chiras J, Simon JM, et al. **Spinal metastases: indications for and results of percutaneous injection of acrylic surgical cement.** Radiology 1996;199:241–47
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=8633152&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 
    
    [Web of Science](http://www.ajnr.org/lookup/external-ref?access_num=A1996UB58400038&link_type=ISI) 

24. Peh WC, Gilula LA, Peck DD. **Percutaneous vertebroplasty for severe osteoporotic vertebral body compression fractures.** Radiology 2002;223:121–26
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=11930056&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 
    
    [Web of Science](http://www.ajnr.org/lookup/external-ref?access_num=000174611900017&link_type=ISI) 

25. Kobayashi K, Shimoyama K, Nakamura K, et al. **Percutaneous vertebroplasty immediately relieves pain of osteoporotic vertebral compression fractures and prevents prolonged immobilization of patients.** Eur Radiol 2005;15:360–67
    
    [CrossRef](http://www.ajnr.org/lookup/external-ref?access_num=10.1007/s00330-004-2549-0&link_type=DOI) 
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=15662480&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 
    
    [Web of Science](http://www.ajnr.org/lookup/external-ref?access_num=000227333900025&link_type=ISI) 

26. Grohs JG, Matzner M, Trieb K, et al. **Minimal invasive stabilization of osteoporotic vertebral fractures: a prospective nonrandomized comparison of vertebroplasty and balloon kyphoplasty.** J Spinal Disord Tech 2005;18:238–42
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=15905767&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 
    
    [Web of Science](http://www.ajnr.org/lookup/external-ref?access_num=000229650200007&link_type=ISI) 

27. Coumans JV, Reinhardt MK, Lieberman IH. **Kyphoplasty for vertebral compression fractures: 1-year clinical outcomes from a prospective study.** J Neurosurg Spine 2003;99:44–50
    
    [CrossRef](http://www.ajnr.org/lookup/external-ref?access_num=10.3171/spi.2003.99.1.0044&link_type=DOI) 

28. Theodorou DJ, Theodorou SJ, Duncan TD, et al. **Percutaneous balloon kyphoplasty for the correction of spinal deformity in painful vertebral body compression fractures.** Clin Imaging 2002;26:1–5
    
    [CrossRef](http://www.ajnr.org/lookup/external-ref?access_num=10.1016/S0899-7071(01)00350-3&link_type=DOI) 
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=11814744&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 
    
    [Web of Science](http://www.ajnr.org/lookup/external-ref?access_num=000174583900001&link_type=ISI) 

29. Feltes C, Fountas KN, Machinis T, et al. **Immediate and early postoperative pain relief after kyphoplasty without significant restoration of vertebral body height in acute osteoporotic vertebral fractures.** Neurosurg Focus 2005;18:e5
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=15844868&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 

30. Kasperk C, Hillmeier J, Noldge G, et al. **Treatment of painful vertebral fractures by kyphoplasty in patients with primary osteoporosis: a prospective nonrandomized controlled study.** J Bone Miner Res 2005;20:604–12
    
    [CrossRef](http://www.ajnr.org/lookup/external-ref?access_num=10.1359/JBMR.041203&link_type=DOI) 
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=15765179&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 
    
    [Web of Science](http://www.ajnr.org/lookup/external-ref?access_num=000227741600008&link_type=ISI) 

31. Ledlie JT, Renfro M. **Balloon kyphoplasty: one-year outcomes in vertebral body height restoration, chronic pain, and activity levels.** J Neurosurg Spine 2003;98:36–42
    
    

32. Gaitanis IN, Hadjipavlou AG, Katonis PG, et al. **Balloon kyphoplasty for the treatment of pathological vertebral compressive fractures.** Eur Spine J 2005;14:250–60
    
    [CrossRef](http://www.ajnr.org/lookup/external-ref?access_num=10.1007/s00586-004-0767-4&link_type=DOI) 
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=15480827&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 
    
    [Web of Science](http://www.ajnr.org/lookup/external-ref?access_num=000228279700006&link_type=ISI) 

33. Berlemann U, Franz T, Orler R, et al. **Kyphoplasty for treatment of osteoporotic vertebral fractures: a prospective non-randomized study.** Eur Spine J 2004;13:496–501
    
    [CrossRef](http://www.ajnr.org/lookup/external-ref?access_num=10.1007/s00586-004-0691-7&link_type=DOI) 
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=15083353&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 
    
    [Web of Science](http://www.ajnr.org/lookup/external-ref?access_num=000224613400004&link_type=ISI) 

34. Crandall D, Slaughter D, Hankins PJ, et al. **Acute versus chronic vertebral compression fractures treated with kyphoplasty: early results.** Spine J 2004;4:418–24
    
    [CrossRef](http://www.ajnr.org/lookup/external-ref?access_num=10.1016/j.spinee.2004.01.003&link_type=DOI) 
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=15246303&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 

35. Rhyne A 3rd, Banit D, Laxer E, et al. **Kyphoplasty: report of eighty-two thoracolumbar osteoporotic vertebral fractures.** J Orthop Trauma 2004;18:294–99
    
    [CrossRef](http://www.ajnr.org/lookup/external-ref?access_num=10.1097/00005131-200405000-00005&link_type=DOI) 
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=15105751&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 
    
    [Web of Science](http://www.ajnr.org/lookup/external-ref?access_num=000221252800005&link_type=ISI) 

36. Phillips FM, Ho E, Campbell-Hupp M, et al. **Early radiographic and clinical results of balloon kyphoplasty for the treatment of osteoporotic vertebral compression fractures.** Spine 2003;28:2260–65
    
    [CrossRef](http://www.ajnr.org/lookup/external-ref?access_num=10.1097/01.BRS.0000085092.84097.7B&link_type=DOI) 
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=14520041&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 
    
    [Web of Science](http://www.ajnr.org/lookup/external-ref?access_num=000185755900013&link_type=ISI) 

37. Lane JM, Hong R, Koob J, et al. **Kyphoplasty enhances function and structural alignment in multiple myeloma.** Clin Orthop Relat Res 2004 :49–53
    
    

38. Majd ME, Farley S, Holt RT. **Preliminary outcomes and efficacy of the first 360 consecutive kyphoplasties for the treatment of painful osteoporotic vertebral compression fractures.** Spine J 2005;5:244–55
    
    [CrossRef](http://www.ajnr.org/lookup/external-ref?access_num=10.1016/j.spinee.2004.09.013&link_type=DOI) 
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=15863078&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 

39. Voggenreiter G. **Balloon kyphoplasty is effective in deformity correction of osteoporotic vertebral compression fractures.** Spine 2005;30:2806–12
    
    [CrossRef](http://www.ajnr.org/lookup/external-ref?access_num=10.1097/01.brs.0000190885.85675.a0&link_type=DOI) 
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=16371909&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 
    
    [Web of Science](http://www.ajnr.org/lookup/external-ref?access_num=000234181300018&link_type=ISI) 

40. Grafe IA, Da Fonseca K, Hillmeier J, et al. **Reduction of pain and fracture incidence after kyphoplasty: 1-year outcomes of a prospective controlled trial of patients with primary osteoporosis.** Osteoporos Int 2005;16:2005–12
    
    [CrossRef](http://www.ajnr.org/lookup/external-ref?access_num=10.1007/s00198-005-1982-5&link_type=DOI) 
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=16078092&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 
    
    [Web of Science](http://www.ajnr.org/lookup/external-ref?access_num=000233997600073&link_type=ISI) 

41. Amar AP, Larsen DW, Esnaashari N, et al. **Percutaneous transpedicular polymethylmethacrylate vertebroplasty for the treatment of spinal compression fractures.** Neurosurgery 2001;49:1105–14
    
    [CrossRef](http://www.ajnr.org/lookup/external-ref?access_num=10.1097/00006123-200111000-00017&link_type=DOI) 
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=11846904&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 
    
    [Web of Science](http://www.ajnr.org/lookup/external-ref?access_num=000171760000021&link_type=ISI) 

42. Diamond TH, Champion B, Clark WA. **Management of acute osteoporotic vertebral fractures: a nonrandomized trial comparing percutaneous vertebroplasty with conservative therapy.** Am J Med 2003;114:257–65
    
    [CrossRef](http://www.ajnr.org/lookup/external-ref?access_num=10.1016/S0002-9343(02)01524-3&link_type=DOI) 
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=12681451&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 
    
    [Web of Science](http://www.ajnr.org/lookup/external-ref?access_num=000182173600001&link_type=ISI) 

43. Teng MM, Wei CJ, Wei LC, et al. **Kyphosis correction and height restoration effects of percutaneous vertebroplasty.** AJNR Am J Neuroradiol 2003;24:1893–900
    
    [Abstract/FREE Full Text](http://www.ajnr.org/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6NDoiYWpuciI7czo1OiJyZXNpZCI7czo5OiIyNC85LzE4OTMiO3M6NDoiYXRvbSI7czoxOToiL2FqbnIvMjgvMi8yMDAuYXRvbSI7fXM6ODoiZnJhZ21lbnQiO3M6MDoiIjt9) 

44. Hiwatashi A, Moritani T, Numaguchi Y, et al. **Increase in vertebral body height after vertebroplasty.** AJNR Am J Neuroradiol 2003;24:185–89
    
    [Abstract/FREE Full Text](http://www.ajnr.org/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6NDoiYWpuciI7czo1OiJyZXNpZCI7czo4OiIyNC8yLzE4NSI7czo0OiJhdG9tIjtzOjE5OiIvYWpuci8yOC8yLzIwMC5hdG9tIjt9czo4OiJmcmFnbWVudCI7czowOiIiO30=) 

45. Dublin AB. **The vertebral body fracture in osteoporosis: restoration of height using percutaneous vertebroplasty**. AJNR Am J Neuroradiol 2004;25
    
    

46. Chin DK, Kim YS, Cho YE, et al. **Efficacy of postural reduction in osteoporotic vertebral compression fractures followed by percutaneous vertebroplasty.** Neurosurgery 2006;58:695–700
    
    [CrossRef](http://www.ajnr.org/lookup/external-ref?access_num=10.1227/01.NEU.0000204313.36531.79&link_type=DOI) 
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=16575333&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 

47. Carlier RY, Gordji H, Mompoint DM, et al. **Osteoporotic vertebral collapse: percutaneous vertebroplasty and local kyphosis correction.** Radiology 2004;233:891–98
    
    [CrossRef](http://www.ajnr.org/lookup/external-ref?access_num=10.1148/radiol.2333030400&link_type=DOI) 
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=15486209&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 

48. McKiernan F, Jensen R, Faciszewski T. **The dynamic mobility of vertebral compression fractures.** J Bone Miner Res 2003;18:24–29
    
    [CrossRef](http://www.ajnr.org/lookup/external-ref?access_num=10.1359/jbmr.2003.18.1.24&link_type=DOI) 
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=12510802&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 
    
    [Web of Science](http://www.ajnr.org/lookup/external-ref?access_num=000180015500005&link_type=ISI) 

49. McKiernan F, Faciszewski T, Jensen R. **Does vertebral height restoration achieved at vertebroplasty matter?** J Vasc Interv Radiol 2005;16:973–79
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=16002505&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 

50. Cloft HJ. **Taking vertebroplasty to a new level or making a mountain out of a molehill?** AJNR Am J Neuroradiol 2005;26:439–40
    
    [FREE Full Text](http://www.ajnr.org/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiRlVMTCI7czoxMToiam91cm5hbENvZGUiO3M6NDoiYWpuciI7czo1OiJyZXNpZCI7czo4OiIyNi8zLzQzOSI7czo0OiJhdG9tIjtzOjE5OiIvYWpuci8yOC8yLzIwMC5hdG9tIjt9czo4OiJmcmFnbWVudCI7czowOiIiO30=) 

51. Choe du H, Marom EM, Ahrar K, et al. **Pulmonary embolism of polymethyl methacrylate during percutaneous vertebroplasty and kyphoplasty.** AJR Am J Roentgenol 2004;183:1097–102
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=15385313&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 
    
    [Web of Science](http://www.ajnr.org/lookup/external-ref?access_num=000224217200040&link_type=ISI) 

52. Syed MI, Jan S, Patel NA, et al. **Fatal fat embolism after vertebroplasty: identification of the high-risk patient.** AJNR Am J Neuroradiol 2006;27:343–45
    
    [Abstract/FREE Full Text](http://www.ajnr.org/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6NDoiYWpuciI7czo1OiJyZXNpZCI7czo4OiIyNy8yLzM0MyI7czo0OiJhdG9tIjtzOjE5OiIvYWpuci8yOC8yLzIwMC5hdG9tIjt9czo4OiJmcmFnbWVudCI7czowOiIiO30=) 

53. Walker DH, Mummaneni P, Rodts GE Jr, et al. **Infected vertebroplasty. Report of two cases and review of the literature.** Neurosurg Focus 2004;17:E6
    
    [CrossRef](http://www.ajnr.org/lookup/external-ref?access_num=10.3171/foc.2004.17.2.2&link_type=DOI) 
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=15329021&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 

54. Garfin SR, Reilley MA. **Minimally invasive treatment of osteoporotic vertebral body compression fractures.** Spine J 2002;2:76–80
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=14588292&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 

55. Nussbaum DA, Gailloud P, Murphy K. **A review of complications associated with vertebroplasty and kyphoplasty as reported to the Food and Drug Administration medical device related web site.** J Vasc Interv Radiol 2004;15:1185–92
    
    [CrossRef](http://www.ajnr.org/lookup/external-ref?access_num=10.1097/01.RVI.0000144757.14780.E0&link_type=DOI) 
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=15525736&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 
    
    [Web of Science](http://www.ajnr.org/lookup/external-ref?access_num=000227678800001&link_type=ISI) 

56. McGraw JK, Cardella J, Barr JD, et al. **Society of Interventional Radiology quality improvement guidelines for percutaneous vertebroplasty.** J Vasc Interv Radiol 2003;14:827–31
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=12847189&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 
    
    [Web of Science](http://www.ajnr.org/lookup/external-ref?access_num=000184102500001&link_type=ISI) 

57. Deramond H, Depriester C, Galibert P, et al. **Percutaneous vertebroplasty with polymethylmethacrylate. Technique, indications, and results.** Radiol Clin North Am 1998;36:533–46
    
    [CrossRef](http://www.ajnr.org/lookup/external-ref?access_num=10.1016/S0033-8389(05)70042-7&link_type=DOI) 
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=9597071&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 
    
    [Web of Science](http://www.ajnr.org/lookup/external-ref?access_num=000073785000006&link_type=ISI) 

58. Padovani B, Kasriel O, Brunner P, et al. **Pulmonary embolism caused by acrylic cement: a rare complication of percutaneous vertebroplasty.** AJNR Am J Neuroradiol 1999;20:375–77
    
    [Abstract/FREE Full Text](http://www.ajnr.org/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6NDoiYWpuciI7czo1OiJyZXNpZCI7czo4OiIyMC8zLzM3NSI7czo0OiJhdG9tIjtzOjE5OiIvYWpuci8yOC8yLzIwMC5hdG9tIjt9czo4OiJmcmFnbWVudCI7czowOiIiO30=) 

59. Cotten A, Dewatre F, Cortet B, et al. **Percutaneous vertebroplasty for osteolytic metastases and myeloma: effects of the percentage of lesion filling and the leakage of methyl methacrylate at clinical follow-up.** Radiology 1996;200:525–30
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=8685351&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 
    
    [Web of Science](http://www.ajnr.org/lookup/external-ref?access_num=A1996UY07800038&link_type=ISI) 

60. Perez-Higueras A, Alvarez L, Rossi RE, et al. **Percutaneous vertebroplasty: long-term clinical and radiological outcome.** Neuroradiology 2002;44:950–54
    
    [CrossRef](http://www.ajnr.org/lookup/external-ref?access_num=10.1007/s00234-002-0856-1&link_type=DOI) 
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=12428134&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 
    
    [Web of Science](http://www.ajnr.org/lookup/external-ref?access_num=000179668100015&link_type=ISI) 

61. Ryu KS, Park CK, Kim MC, et al. **Dose-dependent epidural leakage of polymethylmethacrylate after percutaneous vertebroplasty in patients with osteoporotic vertebral compression fractures.** J Neurosurg 2002;96:56–61
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=11795714&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 

62. Heini PF, Orler R. **Kyphoplasty for treatment of osteoporotic vertebral fractures.** Eur Spine J 2004;13:184–92
    
    [CrossRef](http://www.ajnr.org/lookup/external-ref?access_num=10.1007/s00586-003-0654-4&link_type=DOI) 
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=14986073&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 

63. Uppin AA, Hirsch JA, Centenera LV, et al. **Occurrence of new vertebral body fracture after percutaneous vertebroplasty in patients with osteoporosis.** Radiology 2003;226:119–24
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=12511679&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 
    
    [Web of Science](http://www.ajnr.org/lookup/external-ref?access_num=000180106500018&link_type=ISI) 

64. Kim SH, Kang HS, Choi JA, et al. **Risk factors of new compression fractures in adjacent vertebrae after percutaneous vertebroplasty.** Acta Radiol 2004;45:440–45
    
    [CrossRef](http://www.ajnr.org/lookup/external-ref?access_num=10.1080/02841850410005615&link_type=DOI) 
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=15323398&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 

65. Fribourg D, Tang C, Sra P, et al. **Incidence of subsequent vertebral fracture after kyphoplasty.** Spine 2004;29:2270–76
    
    [CrossRef](http://www.ajnr.org/lookup/external-ref?access_num=10.1097/01.brs.0000142469.41565.2a&link_type=DOI) 
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=15480139&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 
    
    [Web of Science](http://www.ajnr.org/lookup/external-ref?access_num=000224495000012&link_type=ISI) 

66. Harrop JS, Prpa B, Reinhardt MK, et al. **Primary and secondary osteoporosis’ incidence of subsequent vertebral compression fractures after kyphoplasty.** Spine 2004;29:2120–25
    
    [CrossRef](http://www.ajnr.org/lookup/external-ref?access_num=10.1097/01.brs.0000141176.63158.8e&link_type=DOI) 
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=15454702&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 
    
    [Web of Science](http://www.ajnr.org/lookup/external-ref?access_num=000224253500006&link_type=ISI) 

67. Lindsay R, Silverman SL, Cooper C, et al. **Risk of new vertebral fracture in the year following a fracture.** JAMA 2001;285:320–23
    
    [CrossRef](http://www.ajnr.org/lookup/external-ref?access_num=10.1001/jama.285.3.320&link_type=DOI) 
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=11176842&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 
    
    [Web of Science](http://www.ajnr.org/lookup/external-ref?access_num=000166324300023&link_type=ISI) 

68. Delmas PD, Ensrud KE, Adachi JD, et al. **Efficacy of raloxifene on vertebral fracture risk reduction in postmenopausal women with osteoporosis: four-year results from a randomized clinical trial.** J Clin Endocrinol Metab 2002;87:3609–17
    
    [CrossRef](http://www.ajnr.org/lookup/external-ref?access_num=10.1210/jc.87.8.3609&link_type=DOI) 
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=12161484&link_type=MED&atom=%2Fajnr%2F28%2F2%2F200.atom) 
    
    [Web of Science](http://www.ajnr.org/lookup/external-ref?access_num=000177285400016&link_type=ISI) 

69. U.S. Markets for adjunctive and non-fusion spine technologies: report 103-1-US-0103. Cleveland: Health Research International;2003
    
    

70. Myers ME. **Vertebroplasty and kyphoplasty: is one of these procedures the best choice for all patients?** AJNR Am J Neuroradiol 2004;25:1297
    
    [FREE Full Text](http://www.ajnr.org/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiRlVMTCI7czoxMToiam91cm5hbENvZGUiO3M6NDoiYWpuciI7czo1OiJyZXNpZCI7czo5OiIyNS83LzEyOTciO3M6NDoiYXRvbSI7czoxOToiL2FqbnIvMjgvMi8yMDAuYXRvbSI7fXM6ODoiZnJhZ21lbnQiO3M6MDoiIjt9) 

*   Copyright © American Society of Neuroradiology