Vertebroplasty

Despite Vertebroplasty was proposed in 1984 by H. Deramond², this fine spinal interventional technique has undergone significant development in European and USA countries only during last 5 years ^2-8.

Improvement of the technique concerning the injected solutions (PMMA, fluid hydroxiapatite), the wide variety of introducing devices as new mechanical injection systems and CT-guided procedures (figure 1) has not significantly modified the original indication to vertebroplasty, including primary and secondary (generally steroid induced) osteoporosis as well as all neoplastic and paraneoplastic diseases affecting the vertebral body, as expanding cavernous angioma, plasmocytoma, lymphoma, leukemia, aneurysmatic cyst and metastasis⁶. In neoplastic disease, pain resolution and cytotoxic action, besides stabilization of the bone, make Vertebroplasty a technique to be preferred to conventional surgical vertebrectomy.

Figure 1.

CT-guided Vertebroplasty. Axial (A), sagittal (B) and 3D (C) real-time reconstruction during a procedure performed in a patient with T12 osteoporotic fracture. CT real time reconstruction help the operator to select the best way to get the sagittal midline of the pathological vertebral body, reducing accidental involvement of paravertebral soft tissues.

Vertebroplasty and Osteoporosis

Percutaneous vertebroplasty is considered the modality of choice in pain relief and stabilization in case of spinal pain related to osteoporotic fractures. 90% of the patients who undergo Vertebroplasty experiments pain relief in 2 to 30 days from the procedure, and previously described complications are significantly reduced nowadays. According to Murphy and Deramond, indication for Vertebroplasty consist of persistent, severe and often incapacitating focal back pain up to 12 weeks not responding to standard medical therapy and related to one or more collapsed vertebral bodies. Immobilization for a long period in case of older patients could be potentially dangerous, because of complication as phlebothrombosis, muscle atrophy, pulmonary embolism, pneumonia or intolerance to analgesics. Moreover, prolonged bed rest can be responsible for psychological consequences. Vertebroplasty should be used to reduce the pain and the complication of immobilization. Similarly, osteoporotic fracture of the sacrum, that can sometimes be detected only on SPECT imaging, can be treated with percutaneous intrasacral injection of PMMA (sacroplasty).

There are no indications for PV in asymptomatic patients, and prophylactic use of PV is not yet an accepted indication, however one should treat a normal vertebral body if it is between two collapsed vertebra to be treated.

Vertebroplasty and Neoplastic Disease

In case of neoplastic disease affecting the vertebral bodies or the sacrum, Vertebroplasty (and Sacroplasty) should be included in the treatment protocol, including chemo- and/or radioterapy. The cytotoxic effect of the PMMA should be considered an interesting “side effect” of the injection, concurring in tumoral mass destruction. Vertebroplasty does not reduce or change the effect of radiotherapy; moreover vertebral bones previously treated with PMMA injection are less prone to develop secondary disease later.

As a consequenze, Vertebroplasty should precede other treatments, avoiding vertebral body collapse because of the disease. Several reports demonstrated Radiotherapy does not change physico-chemical properties of the cement (elasticity, resistance)⁷: as a consequence, both treatments are to be adopted in the management of a vertebral expanding tumor.

Despite previous reports, a tumoral vertebra with destruction of the posterior wall of the body can be equally treated, although special attention to possible extension of the cement into the spinal canal must be paid: however, the evolution of cementing materials and injection system, as well as the adoption of special technique (injection of a more dense cement, simultaneous myelographic evaluation of the epidural space injection intrathecal iodinate contrast media) allows to treat even patient wit a ghost vertebral body (figure 2).

Figure 2.

Vertebral body destruction in a patient affected by Chronic Myeloid Leukemia and extensive erosion posterior wall of the vertebra body before (A) and after (B) Vertebroplasty. Despite the wide osteolysis of the posterior profile of the vertebral body, percutaneous injection of polymethylmethacrylate was performed, restoring the spinal canal.

On the contrary, posterior arch involvement from the tumor remains contraindication to the vertebroplastic treatment: cementification of the vertebral body only will not stabilize the spine and pain will remain unchanged, being evocated from nocic-mechanoceptors located in the posterior arch.

Differently from common cavernous angioma accounting for the 8.9% - 12.5% of benign vertebral tumors, that does not weak the vertebral body nor is associated to vertebral collapse or pain, expanding angioma can be responsible for bone weakening and pain. Despite the anatomo-pathological structure of expanding angiomas that can be responsible for long distance accidental embolisation via the vena cava or the epidural venous plexus^9,10, we did not find significant bleeding to be considered a frequent side effect of Vertebroplasty, probably in relation to embolising effect (mechanical, chemical and thermal effect) of PMMA.

Expanding aneurysmal cysts of the vertebral body and the sacrum has been also treataed with PMMA injection, with similar results and pain-control effects.

In case of Multiple Myeloma or Plasmocytoma, as well as for Lymphomatous localization to the spine, Vertebroplasty revealed as an important tool for vertebral stabilization and pain relief. Finally, metastatic disease involving the vertebral bodies and/or the sacrum is nawadays one of the main indication for adopting this procedure. Despite several reports in the literature, we did not observed on CT and MRI control scans spreading of neoplastic tissues after the treatment.

Conclusions

Vertebroplasty can be considered a safe, powerful spinal interventional procedure to be used in case of vertebral body or sacrum osteoporotic or neoplastic lesions.