Uni- vs bilateral pedicle screw fixation in minimally invasive lumbar interbody fusion
A Meta-Analysis of Unilateral versus Bilateral Pedicle Screw Fixation in Minimally Invasive Lumbar Interbody FusionPLoS One. 2014 Nov 6;9(11):e111979.
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6 studies (5 randomized controlled trials, 1 clinical controlled trial) encompassing 298 patients were included in this meta-analysis with the purpose of comparing the efficacy and safety of unilateral versus bilateral pedicle screw fixation in minimally invasive lumbar interbody fusion for one-level degenerative lumbar spine disease. Unilateral pedicle screw fixation achieved significantly shorter operative time and reduced blood loss compared to bilateral screw fixation. However, VAS back pain, VAS leg pain, ODI scores, overall fusion rate, overall incidence of complications, and length of hospital stay were similar between uni- and bilateral pedicle screw fixation.
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Detsky AS, Naylor CD, O'Rourke K, McGeer AJ, L'Abbé KA. J Clin Epidemiol. 1992;45:255-65
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Why was this study needed now?
Minimally invasive (MIS) lumbar interbody fusion is advantageous for a variety of lumbar degenerative disorders as it reduces morbidity and offers early ambulation when compared to traditional open surgery. Usually, bilateral pedicle screw (PS) fixation is the standard procedure in lumbar interbody fusion. However, recent studies suggest unilateral PS fixation is an equally effective technique that requires shorter operating time. The objective of this meta-analysis was to compare the efficacy of unilateral versus bilateral PS fixation in MIS lumber interbody fusion for one-level degenerative lumbar spine disease.
What was the principal research question?
How does the efficacy and safety compare between unilateral and bilateral pedicle screw fixation in minimally invasive lumbar interbody fusion for single-level degenerative lumbar spine disease?
What were the important findings?
- Pooled results were similar between unilateral and bilateral groups with respect to VAS back pain (5 studies: MD= -0.02 [95% CI -0.17 to 0.13]; p=0.77), VAS leg pain (3 studies: MD= -0.10 [95% CI -0.20 to 0.01]; p=0.06), and ODI scores (5 studies: MD= 0.31 [95% CI -0.66 to 1.27]; p=0.54).
- The overall fusion rate was not significantly different between the unilateral (134/146) and bilateral (146/152) groups (OR=0.47 [95% CI 0.18 to 1.27]; p=0.14). Likewise, the overall incidence of complications was not significant different between the unilateral (8/146) and bilateral (7/152) groups (OR=1.25 [95% CI 0.44 to 3.59]; p=0.67).
- Operative time was significantly shorter (4 studies; p=0.02) and blood loss was significantly reduced (4 studies; p=0.002) with unilateral pedicle screw fixation, but hospital stay was not significantly different between groups (3 studies; p=0.54).
What should I remember most?
Unilateral and bilateral pedicle screw fixation offered similar clinical outcome and fusion rate in patients undergoing minimally invasive lumbar interbody fusion surgery. Unilateral and bilateral pedicle screw fixation differed in blood loss and operative time, both of which were significantly reduced in unilateral cohorts.
How will this affect the care of my patients?
It appears that unilateral pedicle screw fixation has the ability to shorten operative time and reduce blood loss while achieving similar clinical outcomes and fusion success to bilateral pedicle screw fixation. The authors acknowledge that the presence of methodological limitations, existence of heterogeneity among studies, and lack of complete data recording weaken the results of this study. Additional high-quality randomized controlled trials with large sample sizes and long-term follow-up are necessary before the wider application of unilateral pedicle screw fixation can be recommended.
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