
<b>Vertebroplasty is an minimally invasive technique in which polymethyl methacrylate, a surgical cement, is injected into a vertebral body in order to provide increased strength and immediate and longterm pain relief in vertebrae weakened by bony lesions </b>[metastases, multiple myeloma, aggressive hemangiomas, and osteoporotic fractures].   It is a newly developed technique, reported upon in several case series, including one with 187 subjects.  <b>Percutaneous vertebroplasty can effect significant pain relief and increased mobility in over 70% of patients with osteolytic lesions.  Pain relief was apparent within two days, and persisted for at least months to years.  While it is probable that percutaneous vertebroplasty can also strengthen the vertebral bodies, it is unproven whether it can prevent further fractures in the treated vertebrae.  How long the effects last is not known, as longterm follow-up on cancer patients can be difficult to obtain. </b>[see references.] Pain relief can occur despite insufficient lesion filling. [46]

"Percutaneous vertebroplasty has only recently been introduced as a treatment for osteolytic lesions and osteoporotic compression fractures of the vertebrae, but early results are promising. Up to 80 percent of patients with pain unresponsive to correct medical treatment experience a significant degree of pain relief, and few serious complications have been reported. However, relatively few patients have undergone this procedure, and there are no data from controlled clinical trials or from studies with long-term follow-up. At the present time this procedure is still in the investigational stages, but may be appropriate for patients with no other reasonable options for medical treatment." [45] 

Vertebroplasty is simple and effective but should be performed only in centers with neurosurgical and/or orthopedic surgery units because of the possibility of severe complications. [101] Complications of the procedure were rare. Clinically insignificant leakage of bone cement into the surrounding tissues does occur, but <b>in a few cases the leakage of methacrylate caused neuralgia or pressure on spinal nerve roots. Also reported were several instances of pulmonary embolism.</b> [45]

<b>"Although criteria for use of percutaneous vertebroplasty are still under development, it will probably be considered appropriate treatment for patients with vertebral lesions resulting from osteolytic metastasis and myeloma, hemangioma, and painful osteoporotic compression fractures if the following criteria have been met:
o Severe debilitating pain or loss of mobility that cannot be relieved by correct medical therapy.
o Other causes of pain, such as herniated intervertebral disk have been ruled out by computed tomography or magnetic resonance imaging. 
o The affected vertebra has not been extensively destroyed and is at least one third of its original height. 
o Radiation therapy or concurrent surgical interventions, such as laminectomy, may also be required in patients with compression of the spinal cord due to ingrowth of a tumor."</b> [45]

"We report the pathological findings in cases of acrylic implants obtained by direct intratumoral injection of polymethyl-methacrylate (PMMA) and N-butyl-cyano-acrylate (NBCA). Direct intratumoral injection of acrylic implants was performed for a variety of primary and secondary bone lesions. These types of treatments have been used at our institution in the last 4 years for 40 vertebroplasty (PMMA) procedures and for nine bone lesions of other locations (PMMA, NBCA). Postmortem histology became available for 1 case of PMMA and for 5 cases with NBCA intratumoral acrylic implants. <b>The pathological findings associated with PMMA and NBCA were evaluated and compared. PMMA exhibited a macroscopic and microscopic rim of tumor necrosis, 6 months after implantation.
NBCA exhibited compressive effects on the nearby tumor tissue, however, without signs of significant necrosis outside the acrylic tumor cast. Tumor captured inside the acrylic cast showed extensive to near complete necrosis. Acrylic implants may lead to necrosis when injected directly in tumors. The necrotizing effect may extend beyond the limits of an implant in the case of PMMA. Such an extended effect of PMMA, when compared with NBCA, may be due to the variable toxicity of acrylic implants, including the different degrees of the exothermic reaction during polymerization."</b> [1]

Johns Hopkins radiologists have reported on a series of 205 percutaneous vertebroplasty procedures carried out without pre-treatment venography, avoiding contrast-related complications. There were no major complications or cement leakage in this series.  [Reported in: Murphy, Kieran J., American Journal of Neuroradiology, June 2002. Johns Hopkins.]

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