Percutaneous vertebroplasty for treatment of painful osteoporotic vertebral compression fractures: an evidence-based analysis.

UNLABELLED

OBJECTIVE OF ANALYSIS: The objective of this analysis is to examine the safety and effectiveness of percutaneous vertebroplasty for treatment of osteoporotic vertebral compression fractures (VCFs) compared with conservative treatment.

CLINICAL NEED AND TARGET POPULATION

Osteoporosis and associated fractures are important health issues in ageing populations. Vertebral compression fracture secondary to osteoporosis is a cause of morbidity in older adults. VCFs can affect both genders, but are more common among elderly females and can occur as a result of a fall or a minor trauma. The fracture may occur spontaneously during a simple activity such as picking up an object or rising up from a chair. Pain originating from the fracture site frequently increases with weight bearing. It is most severe during the first few weeks and decreases with rest and inactivity. Traditional treatment of painful VCFs includes bed rest, analgesic use, back bracing and muscle relaxants. The comorbidities associated with VCFs include deep venous thrombosis, acceleration of osteopenea, loss of height, respiratory problems and emotional problems due to chronic pain. Percutaneous vertebroplasty is a minimally invasive surgical procedure that has gained popularity as a new treatment option in the care for these patients. The technique of vertebroplasty was initially developed in France to treat osteolytic metastasis, myeloma, and hemangioma. The indications were further expanded to painful osteoporotic VCFs and subsequently to treatment of asymptomatic VCFs. The mechanism of pain relief, which occurs within minutes to hours after vertebroplasty, is still not known. Pain pathways in the surrounding tissue appear to be altered in response to mechanical, chemical, vascular, and thermal stimuli after the injection of the cement. It has been suggested that mechanisms other than mechanical stabilization of the fracture, such as thermal injury to the nerve endings, results in immediate pain relief.

PERCUTANEOUS VERTEBROPLASTY

Percutaneous vertebroplasty is performed with the patient in prone position and under local or general anesthesia. The procedure involves fluoroscopic imaging to guide the injection of bone cement into the fractured vertebral body to support the fractured bone. After injection of the cement, the patient is placed in supine position for about 1 hour while the cement hardens. Cement leakage is the most frequent complication of vertebroplasty. The leakages may remain asymptomatic or cause symptoms of nerve irritation through compression of nerve roots. There are several reports of pulmonary cement embolism (PCE) following vertebroplasty. In some cases, the PCE may remain asymptomatic. Symptomatic PCE can be recognized by their clinical signs and symptoms such as chest pain, dyspnea, tachypnea, cyanosis, coughing, hemoptysis, dizziness, and sweating.

LITERATURE SEARCH

A literature search was performed on Feb 9, 2010 using OVID MEDLINE, MEDLINE In-Process and Other Non-Indexed Citations, EMBASE, the Cumulative Index to Nursing & Allied Health Literature (CINAHL), the Cochrane Library, and the International Agency for Health Technology Assessment (INAHTA) for studies published from January 1, 2005 to February 9, 2010. Studies were initially reviewed by titles and abstracts. For those studies meeting the eligibility criteria, full-text articles were obtained and reviewed. Reference lists were also examined for any additional relevant studies not identified through the search. Articles with an unknown eligibility were reviewed with a second clinical epidemiologist and then a group of epidemiologists until consensus was established. Data extraction was carried out by the author.

STUDY DESIGN

Randomized controlled trials (RCTs) comparing vertebroplasty with a control group or other interventions

STUDY POPULATION

Adult patients with osteoporotic vertebral fracturesSTUDY SAMPLE SIZE: Studies included 20 or more patientsEnglish language full-reportsPublished between Jan 1 2005 and Feb 9, 2010(eligible studies identified through the Auto Alert function of the search were also included)

EXCLUSION CRITERIA

Non-randomized studiesStudies on conditions other than VCF (e.g. patients with multiple myeloma or metastatic tumors)Studies focused on surgical techniquesStudies lacking outcome measures RESULTS OF EVIDENCE-BASED ANALYSIS: A systematic search yielded 168 citations. The titles and the abstracts of the citations were reviewed and full text of the identified citations was retrieved for further consideration. Upon review of the full publications and applying the inclusion and exclusion criteria, 5 RCTs were identified. Of these, two compared vertebroplasty with sham procedure, two compared vertebroplasty with conservative treatment, and one compared vertebroplasty with balloon kyphoplasty.

RANDOMIZED CONTROLLED TRIALS

Recently, the results of two blinded randomized placebo-controlled trials of percutaneous vertebroplasty were reported. These trials, providing the highest quality of evidence available to date, do not support the use of vertebroplasty in patients with painful osteoporotic vertebral compression fractures. Based on the results of these trials, vertebroplasty offer no additional benefit over usual care and is not risk free. In these trials the treatment allocation was blinded to the patients and outcome assessors. The control group received a sham procedure simulating vertebroplasty to minimize the effect of expectations and to reduce the potential for bias in self-reporting of outcomes. Both trials applied stringent exclusion criteria so that the results are generalizable to the patient populations that are candidates for vertebroplasty. In both trials vertebroplasty procedures were performed by highly skilled interventionists. Multiple valid outcome measures including pain, physical, mental, and social function were employed to test the between group differences in outcomes. Prior to these two trials, there were two open randomized trials in which vertebroplasty was compared with conservative medical treatment. In the first randomized trial, patients were allowed to cross over to the other arm and had to be stopped after two weeks due to the high numbers of patients crossing over. The other study did not allow cross over and recently published the results of 12 months follow-up. The following is the summary of the results of these 4 trials: Two blinded RCTs on vertebroplasty provide the highest level of evidence available to date. Results of these two trials are supported by findings of an open randomized trial with 12 months follow-up. Blinded RCTs showed: No significant differences in pain scores of patients who received vertebroplasty and patients who received a sham procedure as measured at 3 days, 2 weeks and 1 month in one study and at 1 week, 1 month, 3 months, and 6 months in the other.The observed differences in pain scores between the two groups were neither statistically significant nor clinically important at any time points.The above findings were consistent with the findings of an open RCT in which patients were followed for 12 months. This study showed that improvement in pain was similar between the two groups at 3 months and were sustained to 12 months.In the blinded RCTs, physical, mental, and social functioning were measured at the above time points using 4-5 of the following 7 instruments: RDQ, EQ-5D, SF-36 PCS, SF-36 MCS, AQoL, QUALEFFO, SOF-ADLThere were no significant differences in any of these measures between patients who received vertebroplasty and patients who received a sham procedure at any of the above time points (with a few exceptions in favour of control intervention).These findings were also consistent with the findings of an open RCT which demonstrated no significant between group differences in scores of ED-5Q, SF-36 PCS, SF 36 MCS, DPQ, Barthel, and MMSE which measure physical, mental, and social functioning (with a few exceptions in favour of control intervention).One small (n=34) open RCT with a two week follow-up detected a significantly higher improvement in pain scores at 1 day after the intervention in vertebroplasty group compared with conservative treatment group. However, at 2 weeks follow-up, this difference was smaller and was not statistically significant.Conservative treatment was associated with fewer clinically important complicationsRisk of new VCFs following vertebroplasty was higher than those in conservative treatment but it requires further investigation.