Efficacy of Using Intermediate Screws in Short-Segment Fixation for Thoracolumbar Fractures: A Meta-Analysis of Randomized Controlled Trials

Some studies have reported that the conventional intersegmental pedicle screws (4-screw fixation [4S]) device for thoracolumbar fractures was associated with inadequate reduction of fractured vertebrae, insufficient correction of kyphosis, and implant failure. Recently, a series of biomechanical studies has confirmed that the addition of intermediate fixation screws (6-screw fixation [6S]) could provide stronger fixation and better reduction of fractured vertebrae. Nevertheless, the clinical and radiologic efficacy of the additional intermediate screws remains unclear. A meta-analysis of randomized controlled trials was used to compare clinical and radiologic outcomes and complications of posterior pedicle screws combined with intermediate screws fixation versus conventional intersegmental pedicle screw fixation. We comprehensively searched MEDLINE, OVID, and Springer according to a search strategy, selecting articles based on inclusion criteria, and extracted data from these reports. Risk of bias in included studies was assessed. Pooled estimates and corresponding 95% confidence intervals were calculated. Six randomized controlled trials involving 310 patients were evaluated in this meta-analysis. Pooled estimates showed statistically similar baseline characteristics, hospital stays, postoperative visual analog scale scores, and infection rates between the 4S group and the 6S group. The 6S group had significantly less correction loss of segmental angle and of anterior vertebral height compression, and lower implant failure rate. The 6S group also showed a slightly longer operative time and more blood loss than did the 4S group. Based on our analysis, the combined intermediate screws fixation technique was associated with significantly improved radiologic outcomes but did not seem to compromise other perioperative outcomes.