Balloon kyphoplasty is a similar, newer procedure in which the spinal augmentation is achieved by first inflating a balloon inside the fractured vertebrae to create a void or cavity. The balloon is then deflated and removed, and PMMA is inserted into the newly created cavity of the affected vertebral body.5 As with vertebroplasty, kyphoplasty can stabilize the vertebrae with the additional potential benefits of restoring vertebral height and correcting kyphosis. These advantages are coupled with a lower potential risk of cement extravasation compared with vertebroplasty.3 Vertebroplasty typically requires a unipedicular approach, while kyphoplasty often requires a bipedicular approach using a larger specialized cannula.3 As a result, kyphoplasty is a more expensive procedure.
Kyphoplasty is a more complex procedure, requires a longer time to complete, and patients may be more likely to need general anesthetic; therefore, vertebroplasty may be preferred in some cases. At present, well-conducted, randomized, controlled trials showing evidence that supports kyphoplasty as superior to vertebroplasty for either osteoporosis or tumor-related vertebral compression fractures is insufficient.10 Efficacy of each procedure rests in the experience of the operator.
IDENTIFYING THE IDEAL CANDIDATES
Vertebroplasty should be explored for those patients with myelomatous vertebral fractures associated with well-localized, disabling pain intractable to conservative management strategies such as analgesic medications, bed rest, use of braces, and rehabilitation services. Suitable candidates for the surgery will also have experienced both functional decline and diminished quality of life. The patient, caregiver, and members of the multidisciplinary team, including the oncology nurse, oncologist, radiologist, and spinal surgeon, must be involved in deciding whether or not a patient is a candidate for this procedure. A thorough assessment and consultation is required to identify those who will benefit from the intervention. Multiple factors are reviewed including clinical presentation, performance status, functional capacity, location of the fracture, extent of disease, and quality of life.5
The presence of localized pain is the most important indication for vertebroplasty; however, a clear correlation must be made between the patient’s reports of pain and the level of fracture. Not all VCFs are painful; therefore, other possible causes of the patient’s pain must be explored.4 Additional indications for vertebroplasty include perioperative and postoperative surgical risks that preclude open spinal surgery.1,3,5-7
Contraindications for vertebroplasty include uncorrected coagulopathy, severe cardiopulmonary insufficiency, systemic or local infection at the site of planned injection, intolerance to prone positioning, spinal cord compression or symptomatic epidural compression of the neural elements, and allergy to procedure-related drugs and materials.4-7,9 Prior to selection for the vertebroplasty procedure, each patient must undergo a preoperative work-up that includes, but is not limited to, a recent chest radiograph, an electrocardiogram (EKG), and baseline blood work including international normalized ratio (INR) to rule out coagulopathy.
After addressing these initial considerations, imaging studies are necessary to further determine candidacy and to rule out other causes of back pain.5 Plain radiographs can be used to identify bone thinning, lytic lesions, and fractures. These radiographs are also necessary to ensure visualization of pedicles, to establish route of entry prior to fluoroscopy, and to ensure there is no evidence of osseous destruction, meaning that the dorsal vertebral wall is intact.7 Further imaging is required to obtain a more detailed visualization of any damaged bone. Computed tomography (CT) scans help determine the exact location and severity of a fracture. In addition, CT scans can further reveal the extent of osseous destruction of the posterior vertebral cortex. Magnetic resonance imaging (MRI) has the advantage of showing the detail of the bone marrow and can evaluate for nerve root compression without exposing the patient to radiation. If the MRI reveals significant epidural soft tissue disease or cord compromise, consultation with radiation oncology is recommended prior to exploring vertebroplasty, as the mass size may need to be reduced through radiation treatment before vertebral augmentation.4,7 In addition, if vertebral lysis is evident, vertebroplasty may be used as an adjunct to radiation to prevent tumor growth.5
POTENTIAL BENEFITS OF VERTEBROPLASTY
Percutaneous vertebroplasty is now considered a suitable therapeutic option for myelomatous vertebral compression fractures. The procedure is minimally invasive, well tolerated with low complication rates, and provides both immediate and long-lasting pain relief.1,3,5,6,9,11 This procedure is preferred over other treatment options as it is usually performed under local anesthesia and allows for same-day discharge from hospital.2,3,7 Successful spinal augmentation often improves patient mobility and decreases the need for analgesics thus avoiding the troublesome side effects of these medications.3,5,8 A recent retrospective study of patients who had undergone vertebroplasty noted significant improvements in patients’ reports of fatigue, depression, anxiety, drowsiness, and difficulty thinking as a result of spinal augmentation.11
The PMMA powder used in the procedure may have some antitumor effects that could produce additional long-lasting benefits for patients with multiple myeloma. Researchers hypothesize that this benefit may be related to cytotoxic and thermal effects that can destroy pain receptors and nerve endings in the affected vertebrae.3,5,7,8,10 In addition, once PMMA is inserted into vertebrae, the space-occupying effect that occurs may also inhibit future growth of tumor cells.10 Regardless if this holds true or not, vertebroplasty is associated with a wide range of benefits, most notably the rapid pain relief and increased performance status ensuring patients with multiple myeloma can continue their systemic treatment.
POTENTIAL COMPLICATIONS OF VERTEBROPLASTY
Although vertebroplasty is known to be an effective treatment with a low complication rate, the procedure does have potential risks.6 Most patients will experience some level of discomfort during administration of the local anesthetic. Additionally, as in any procedure in which the skin is penetrated, there is a potential risk of infection.8
The most serious perioperative risk is leakage of the cement out of the vertebral body through fracture fissures or vertebral vein fissures.1,3,5,6,8,10 This complication is more likely to occur when patients have myeloma with osteolytic destruction of cortical bone and disruption of the posterior wall.4,5 The risk is further escalated when multilevel vertebroplasty is attempted and when the maximum of 4 cc of PMMA per vertebrae is exceeded.4,10
Cement leakage into the epidural space and perivertebral veins is usually asymptomatic but can lead to pulmonary embolism and neurologic problems such as myelopathy and radiculopathy.1,2 A more serious problem may occur if the leakage is in a dangerous location such as the spinal canal, requiring emergent spine surgery to decompress the spinal canal.5 The potential consequences of cement leakage must be weighed against the overall benefit intended to be achieved by percutaneous vertebroplasty in patients with multiple myeloma.