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A systematic review and meta-analysis of randomized controlled trials of unilateral versus bilateral kyphoplasty for osteoporotic vertebral compression fractures.

BACKGROUND
Kyphoplasty reduces the pain caused by osteoporotic vertebral compression fracture (OVCF). Although the procedure is typically carried out using a bilateral approach, it is now increasingly performed using a unilateral approach because of the concern for long-term adverse effects. However, little evidence is available to demonstrate superior safety of the unilateral approach.


OBJECTIVE
The purpose of this study was to compare the short- and long-term safety and efficacy of unilateral vs. bilateral kyphoplasty.


STUDY DESIGN
A systematic review and meta-analysis of randomized controlled trials.


SETTINGS
MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and abstracts published in the related orthopedic journals were systematically searched up to September 2012, using "unilateral kyphoplasty" and "osteoporotic vertebral compression fractures" as key words.


METHODS
Two investigators independently searched and identified relevant reports and abstracts using the PRISMA statement criteria. Relevant studies cited by the identified papers were also included. The level of evidence was classified as good, fair, and limited (or poor) based on the quality of evidence developed by the U.S. Preventive Services Task Force (USPSTF).


RESULTS
Four randomized controlled trials (RCTs) of 159 cases were enrolled. The methodological quality of the articles was determined as moderate. We did not find any significant difference between unilateral and bilateral kyphoplasty on pain relief, in either short-term or long-term follow-up (P = 0.65 and P = 0.69, respectively). The rate of adjacent vertebral fracture was not statistically different with a P value of 0.88 and 95% CI (confidence intervals) of 0.25-3.26. Cement leakage was comparable between unilateral and bilateral kyphoplasty (P = 0.56, 95% CI = 0.46-4.26). The loss of vertebral height in long-term follow-up was not different (P = 0.10, 95% CI = -0.39-4.54). Operation time and cement dosage were considerably less for unilateral kyphoplasty (P < 0.01 and P < 0.05, respectively).


LIMITATIONS
Only 4 RCTs and 159 patients were included in this systematic review. Publication bias also existed among the studies included.


CONCLUSIONS
Both unilateral and bilateral kyphoplasty are effective in alleviating the back pain caused by OVCF. Two approaches have the same degree of safety. More RCTs are needed to examine the efficacy and adverse reactions of the 2 approaches.