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Extrapedicular Vertebral Augmentation to Treat T7-T8 Vertebral Compression Fractures with Retropulsion

AVAflex® curved vertebral augmentation needle

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An 82-year-old Caucasian female with osteoporosis presented with excruciating (9/10) mid-thoracic back pain following a fall backward approximately one week prior.

Her osteoporosis is currently managed with Fosamax.  She has chronic obstructive pulmonary disease (COPD) and takes Coumadin.


  • Pain is localized to the interscapular region
  • At the T7 level there is significant paravertebral muscle spasm, point and percussion tenderness
  • Posture is kyphotic
  • She is unable to walk and range of motion is significantly impaired despite intravenous analgesic medications and muscle relaxants
  • Neurologic examination was non-focal

Pre-treatment Image

MRI demonstrated acute compression fractures with approximately 50% loss of vertebral height at T7-T8 and mild retropulsion into the spinal canal.

Sagittal MRI, acute T7-T8 vertebral compression fractures with mild retropulsion into the canalFigure 1 

Pre-operative Treatment

  • IV analgesics
  • Muscle relaxants
  • Brace treatment combined with bed elevation was attempted and stopped due to intolerable pain


T7-T8 vertebral compression fractures with retropulsion

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Selected Treatment

The patient was not a candidate for an open fixation and decompressive procedure, but requested a minimally invasive option to address her pain.

The right pedicle was not well visualized on fluoroscopy due to her fracture, thus a left-sided approach was necessary. Unilateral access was gained through an extrapedicular approach using an 11G cannula at both T7 and T8.

Inflating a kyphoplasty balloon may carry an increased risk of moving the bone fragments, which may result in cord compression.  Therefore, the AVAflex® curved vertebral augmentation needle (AVAmax® Advanced Vertebral Augmentation System, CareFusion, Waukegan, IL) was used for cavity creation and to provide targeted cement placement further away from bone fragments.

Intra-procedural image

pre-treatment intra-op fluoroscopic image; T7-T8Figure 2

Using the AVAmax® PLUS delivery system (AVAmax® Advanced Vertebral Augmentation System, CareFusion, Waukegan, IL), approximately 2 cc of polymethylmethacrylate cement (PMMA) was slowly deployed in T7 and 3.5 cc of cement in T8.

T7-T8 intra-operative fluoroscopy; VCFFigure 3A. T7

T7-T8 intra-operative fluoroscopy; VCFFigure 3B. T8

The patient tolerated the procedure without complication. Fluoroscopic images confirmed the void was completely filled with cement, with good interdigitation providing structural support.

Post-procedural images

T7-T8, AP, post kyphoplasty Figure 4A. Posteroanterior, T7-T8

T7-T8, lateral, post kyphoplastyFigure 4B. Lateral, T7-T8

The patient reported experiencing 80% pain relief within 15 minutes post-procedure.

Surgeon's Treatment Rationale

Historically, retropulsion of greater than 20%1 is a relative contraindication of performing vertebral augmentation. The patient was not a candidate for an open procedure. Use of the AVAflex curved needle enabled unilateral access, providing a viable treatment option to such a challenging clinical case.

1.  Christie SD, Song JK, Fessler RG. Vertebroplasty and Kyphoplasty for Percutaneous Vertebral Compression Fractures.  APS Bulletin, Volume 15, Number 3, Summer 2005.


At four weeks post-procedure, the patient reported 100% pain relief.


Promotional material provided by CareFusion.

The physician author of this case has been compensated for his illustration by CareFusion.

1500 Waukegan Road
McGaw Park, Il 60085

Case Discussion

With this case, Florida neurosurgeon John K. B. Afshar, MD, presents utilization of the AVAflex® curved vertebral augmentation needle system in an 82-year-old female with osteoporotic fractures. In that the patient reportedly is unable to walk one-week after a fall, percutaneous vertebral augmentation was offered. The patient was on Coumadin, but no mention of reversal is made. Aside from medications, no mention of bracing or other non-operative treatment modalities is offered.

The patient has depressed lower extremity reflexes without evidence of myelopathy or other neurologic impairment. Dr. Afshar diagnosed the patient with acute compression fractures with retropulsion (i.e., burst fractures). We have limited pre-operative MRI information, but only the T8 vertebral body has a significant cleft under the superior endplate. There is more canal intrusion at the T7 level, but this level appears more chronic on the non-cropped image presented.

Dr. Afshar performed a unilateral approach to both T7 and T8 with an 11-gauge cannula. He notes that this patient “was not a candidate for an open fixation and decompressive procedure,” but, of course, there is no indication for open surgery in a neurologically intact patient one week out from trauma.

In low energy trauma, frank fracture fragments with marked cortical compromise are rare with retropulsion. Instead, the posterior cortex bows into the canal with vertebral height loss. As such, this finding does not significantly increase the risk of PMMA leakage into the spinal canal. There is no direct evidence that a particular percentage of canal compromise contraindicates vertebroplasty. Instead, the Society of Interventional Radiology recommends that vertebroplasty be avoided when retropulsion causes neurologic symptoms or a high degree of canal stenosis.1-3

As would be expected with either operative or non-operative management, the outcome in this case was good.

As someone who has performed vertebroplasty and kyphoplasty procedures with straight and curved needles in vertebral compression fractures, burst fractures, and tumors since 1999, I am interested in new techniques to improve the safety and efficiency of vertebral body augmentation.

That said, the controversy surrounding these procedures requires us to look at each “advance” with a jaundiced eye. That is, given that many are debating whether these procedures offer treated patients any more than a placebo effect, additional claims require data support.

In 2009, Kallmes et al and Buchbinder, et al published two randomized clinical trials in which outcomes after vertebroplasty were not significantly different from non-operative management.4 Those trials were criticized for issues including fracture chronicity and patient selection. These authors subsequently addressed some of these concerns by combining their data sets.5

The CAFÉ trial found that kyphoplasty was associated with excellent 1-month relief of pain when compared with non-surgical management.6 Other recent trials show benefits of vertebroplasty.7 Survivor analysis suggests better results with vertebroplasty.8,9 For both procedures, further trials are under way.10,11 In some ways; however, the 2009 publications have had a major impact on the future of percutaneous vertebral augmentation (VBA) procedures in North America. Payers are increasingly denying payment. In particular, many require a six-week course of non-operative management before covering them.

In the last year, a number of papers have reported the changing trends in VBA utilization, who is performing them and where they are being done.12,13 Luetmer and Kallmes report that their own referrals for vertebroplasty have declined, but they continue to offer the procedure to a high percentage of those referred.14 This year, the American Academy of Orthopaedic Surgeons released their “Clinical Practice Guideline: the Treatment of Symptomatic Osteoporotic Spinal Compression Fractures.” Herein, based on the two New England Journal of Medicine articles, vertebroplasty was found lacking of literature support and not recommended. Weak evidence supported ongoing use of kyphoplasty.15

Given the larger debate, any evidence-based look at a new vertebroplasty device is almost impossibly mired in controversy. Specifically, a case report cannot establish the safety or efficacy of a device like the AVAflex® curved vertebral augmentation needle system. We can, however, look at recent publications in this area to get a sense for the likely role of the system.

The question: Can a percutaneous procedure be used in osteoporotic burst fractures? If enough vertebral height is lost, there will be some bony encroachment into the canal. That bone behaves very differently from retropulsed fragments associated with high energy fractures.16,17 A CT scan may be helpful in more closely assessing the continuity of the posterior vertebral cortex. Certainly, many studies have shown little downside to vertebroplasty in the context of low energy osteoporotic, burst fracture.18-23

The jury is still out relative to leak risk for vertebroplasty procedures vs. kyphoplasty. Given that kyphoplasty is more often performed under general anesthesia, medical risks are likely higher for that intervention. Most studies suggest similar early pain outcomes.24 Long-term outcomes differences related to fraction reduction may exist, but remain unproven.25

Liquid PMMA can extravasate into the vascular tree and, in one recent case, even require open heart surgery for removal.26 Kyphoplasty procedures seem to offer lower leak rates partly due to placement of PMMA into a void, but also the 8-gauge instruments allow a more viscous PMMA to be placed.27-29 In one recent study, cement viscosity was at least as strong a predictor for PMMA leakage as retropulsion.30 Typically, smaller gauge needles, such as the 11-gauge system used here, require less viscous PMMA be used.17

Volume of PMMA injected is another predictor of leakage. In this case, 2 and 3.5 cc of PMMA was injected into T7 and T8, respectively. To my view, there was some posterior retropulsion in the T8 level. Of course, a CT would be required to prove this. (See Figure below). 

lateral x-ray, T7-T8Figure 4B. Lateral, T7-T8

No one knows how much PMMA is really needed. Most studies have not controlled for volume of PMMA injected or the fraction of the vertebral centrum filled.31

Leakage and PMMA control continue to stimulate procedural tweaks and new implants, such as stents,32 radiofrequency agitation of the PMMA to control the rate of polymerization,33 and implanted cages.34 Depending on the implants selected and whether the procedure has been performed inpatient or outpatient, more than $4,000 can be saved with “plain” vertebroplasty as compared with kyphoplasty and intermediate procedures such as the one described here.35

In summary, Dr. Afshar presents an interesting case of two-level osteoporotic fractures; one compression and one burst fracture. He uses a unilateral, extrapedicular approach to place PMMA. His patient had a great outcome and he should be congratulated. 

I take issue with a number of his statements, however. First, in a low energy fracture, there is little chance that a balloon will increase “retropulsion” of bone into the canal. Second, assuming the posterior cortex is only bowed; osteoporotic burst fractures can be treated with percutaneous means. Third, to decrease leakage, my recommendations are to use a larger gauge needle to allow more viscous cement. When needed, a bilateral approach allows smaller volumes of PMMA to be injected at a time.

1. Hiwatashia A, Westessona PLA. Vertebroplasty for Osteoporotic Fractures with Spinal Canal Compromise. American Journal of Neuroradiology. April 2007. 28:690-692.
2. McGraw JK, Cardella J, Barr JD, et al. Society of Interventional Radiology Quality Improvement Guidelines for Percutaneous Vertebroplasty. Journal of Vascular and Interventional Radiology. 2003. 14:S311-S315.
3. Shin JJ, Chin DK, Yoon YS. Percutaneous vertebroplasty for the treatment of osteoporotic burst fractures. Acta Neurochirurgica. 2009. 151:141-148.
4. Kallmes DF, et al. A randomized trial of vertebroplasty for osteoporotic spinal fractures. The New England Journal of Medicine. 2009. 361(6):569-79.
5. Staples MP, et al. Effectiveness of vertebroplasty using individual patient data from two randomised placebo controlled trials: meta-analysis. The British Medical Journal. 2011. 343:d3952.
6. Berenson J, et al. Balloon kyphoplasty versus non-surgical fracture management for treatment of painful vertebral body compression fractures in patients with cancer: a multicentre, randomised controlled trial. The Lancet Oncology. 2011. 12(3):225-35.
7. Farrokhi MR, Alibai E, and Maghami Z. Randomized controlled trial of percutaneous vertebroplasty versus optimal medical management for the relief of pain and disability in acute osteoporotic vertebral compression fractures. Journal of Neurosurgery, Spine. 2011. 14(5):561-9.
8. Gerling MC, et al. Cement augmentation of refractory osteoporotic vertebral compression fractures: survivorship analysis. Spine. 2011. 36(19): E1266-9.
9. Edidin AA, et al. Mortality risk for operated and nonoperated vertebral fracture patients in the Medicare population. Journal of Bone and Mineral Research. 2011. 26(7):1617-26.
10. Firanescu C, et al. A randomised sham controlled trial of vertebroplasty for painful acute osteoporotic vertebral fractures (VERTOS IV). Trials. 2011. 12:93.
11. Georgy B. Can meta-analysis save vertebroplasty? American Journal of Neuroradiology. 2011. 32(4):614-6.
12. Goz V, et al. Kyphoplasty and vertebroplasty: trends in use in ambulatory and inpatient settings. The Spine Journal. 2011. Aug 19. [Epub ahead of print]
13. Leake CB, et al. Trends of Inpatient Spine Augmentation: 2001-2008. American Journal of Neuroradiology. 2011. 32:1464.
14. Luetmer MT, Kallmes DF. Have referral patterns for vertebroplasty changed since publication of the placebo-controlled trials? American Journal of Neuroradiology. 2011. 32(4):647-8.
15. McGuire R. AAOS Clinical Practice Guideline: the Treatment of Symptomatic Osteoporotic Spinal Compression Fractures. The Journal of the American Academy of Orthopaedic Surgeons. 2011. 19(3):183-4.
16. Patel AA, et al. Neurologic deficit following percutaneous vertebral stabilization. Spine. 2007. 32(16):1728-34.
17. Truumees E, Hilibrand A, Vaccaro A. Percutaneous Vertebral Augmentation. The Spine Journal. 2004. 4(2):218-229.
18. Li CH, et al. Osteoporotic burst fracture with spinal canal compromise treated with percutaneous vertebroplasty. Clinical Neurology and Neurosurgery. 2010. 112(8):678-81.
19. Gan M, et al. Kyphoplasty for the treatment of painful osteoporotic thoracolumbar burst fractures. Orthopedics. 2010. 33(2):88-92.
20. Kruger A, et al. Kyphoplasty for the treatment of incomplete osteoporotic burst fractures. European Spine Journal. 2010. 19(6):893-900.
21. Doody O, et al. Vertebroplasty in the management of traumatic burst fractures: a case series. Journal of Medical Imaging and Radiation Oncology. 2009. 53(5):489-92.
22. Huet H, et al. Burst-fractures and cementoplasty. Journal of Neuroradiology. Journal de Neuroradiologie. 2005. 32(1):33-41; Discussion 41.
23. Chen JF, Lee ST. Percutaneous vertebroplasty for treatment of thoracolumbar spine bursting fracture. Surgical Neurology. 2004. 62(6):494-500; Discussion 500.
24. Han S, et al. Percutaneous vertebroplasty versus balloon kyphoplasty for treatment of osteoporotic vertebral compression fracture: a meta-analysis of randomised and non-randomised controlled trials. International Orthopaedics. 2011. 35(9):1349-58.
25. Hargunani R, et al. Percutaneous vertebral augmentation: the status of vertebroplasty and current controversies. Seminars in Musculoskeletal Radiology. 2011. 15(2):117-24.
26. Dash A, Brinster DR. Open heart surgery for removal of polymethylmethacrylate after percutaneous vertebroplasty. The Annals of Thoracic Surgery. 2011. 91(1):276-8.
27. Kim KH, et al. Kyphoplasty versus Vertebroplasty: Restoration of Vertebral Body Height and Correction of Kyphotic Deformity With Special Attention to the Shape of the Fractured Vertebrae. Journal of Spinal Disorders & Techniques. 2011 Jun 23. [Epub ahead of print]
28. Li X, et al. Comparison of Kyphoplasty and Vertebroplasty for Treatment of Painful Osteoporotic Vertebral Compression Fractures: Twelve-month Follow-up in a Prospective Nonrandomized Comparative Study. Journal of Spinal Disorders & Techniques. 2011 Mar 16. [Epub ahead of print]
29. Brunton S, et al. Vertebral compression fractures in primary care: recommendations from a consensus panel. Journal Family Practice. 2005. 54(9):781-8.
30. Nieuwenhuijse MJ, Van Erkel AR, Dijkstra PD. Cement leakage in percutaneous vertebroplasty for osteoporotic vertebral compression fractures: identification of risk factors. The Spine Journal. 2011. Sep 1. [Epub ahead of print]
31. Jin YJ, et al. The volumetric analysis of cement in vertebroplasty: relationship with clinical outcome and complications. Spine. 2011. 36(12):E761-72.
32. Klezl Z, et al. Early results after vertebral body stenting for fractures of the anterior column of the thoracolumbar spine. Injury. 2011. May 8. [Epub ahead of print]
33. Robertson SC. Percutaneous vertebral augmentation: StabilitiT a new delivery system for vertebral fractures. Acta Neurochirurgica. Supplement. 2011. 108191-5.
34. Li KC, et al. Transpedicle body augmenter in painful osteoporotic compression fractures. European Spine Journal. 2007. 16(5):589-98.
35. Mehio AK, et al. Comparative hospital economics and patient presentation: vertebroplasty and kyphoplasty for the treatment of vertebral compression fracture. American Journal of Neuroradiology. 2011. 32(7):1290-4.


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