Opinion: More research needed to expand the indications of vertebroplasty

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Vertebroplasty was first described in 1984 to treat difficult cases of angioma where the surgical treatment was difficult and the idea was excellent. Following this first step, patients with vertebral metastases, again difficult to treat because they are fragile and with a high risk of infections, were treated with the same vertebroplasty technique with excellent success. Those two primary indications were taken because surgery was difficult, dangerous or with a high risk of complications.

The second step was the treatment of  pseudarthrosis occuring in patients with vertebral compression fracture (VCF) and osteoporosis. Surgical treatment again was possible, but with poor results with regard to the high risk of complications. The vertebroplasty was effective to stop or decrease the pain and it became a successful technique to treat elderly patients with pseudarthrosis for VCF. At this point, some radiologists got the idea of treating even fresh fractures (VCF) to try to decrease the duration of the painful period that always occurs when treating those osteoporotic patients with a brace. The orthopaedic treatment works, but the bone healing process takes six to eight weeks. Here the logic began to miss the target. Injecting cement in fresh fractured vertebra does not promote bone healing, and can, in fact, stop or avoid good bone healing. Using the vertebroplasty technique in this indication provides a high risk of cement leakage and there is no reduction of the fracture itself.

 

The idea of kyphoplasty, which is a great idea, was to use a balloon to compact the cancellous bone inside the fractured vertebra allowing us to decrease cement leakage (this was demonstrated in prospective randomised studies) and to reduce the angulation of the VCF. This last point has never been demonstrated in any prospective randomised studies. The positioning of the patient on the surgical table seems to be the most effective way of obtaining the reduction.

 

Since this time, there has been confusion in the literature about vertebroplasty and kyphoplasty and the indications for the use of those techniques to treat VCF. The first question is the indication: who is the best doctor to take the decision? It seems to me that spine surgeons who have good knowledge of spine biomechanics and are able to treat spinal cord or nerve root compression are the right persons. Performing a vertebroplasty or kyphoplasty without biomechanical knowledge and without the competence to treat complications, does not seem reasonable. The second question is: if everybody agrees about the efficacy of the balloon to avoid cement leakage, is there evidence that kyphoplasty or similar techniques allow a reduction in the angulation of the fractured vertebra? The answer is no. Injecting cement in a fresh fracture is not a logical procedure because it stops the bone healing process. Some teams started to promote the use of bone substitutes to try to solve the problem. The concept is good, but unfortunately today there is no injectable bone substitute with a good resistance in compression able to stabilise a VCF. 50Mpa are requested and the best substitutes provide less than 10Mpa. Those substitutes should be resorbable like the tricalcium phosphate to promote bone healing.

 

Finally the argument for using cement injection in vertebrae to shorten the painful period is very weak, and not supported by strong literature to push forward these indications. Even if the last two papers published in August 2009 in the New Englang Journal of Medicine were not in favour of vertebroplasty, there is some interest to try to find a solution to solve VCFs in the elderly because multiple fractures lead to mechanical problems like kyphosis. In young patients, use of vertebroplasty is more questionable until high-quality literature demonstrates the advantages with the use of a bioresorbable substance with strong compressive strength.

 

Why did we increase indications for vertebroplasty and kyphoplasty for fresh VCF when there is no evidence of efficacy in the literature? The primary indications for angioma and metastases were appropriate. More development and research are requested to expand the indications to fresh VCF in young patients.

 

Jean-Charles Le Huec is professor and chief of Spine Unit and chairman of Department of Orthopaedic and Traumatology at Bordeaux University Hospital, Bordeaux, France

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