Do More Screws Mean Better Stability? Four (4S) vs. Six (6S) Screws for Short-Segment Fixation in Thoracolumbar...

Purpose: Thoracolumbar burst fractures represent a significant proportion of spinal injuries, with management strategies remaining a subject of debate. While four-screw (4S) short-segment posterior fixation is commonly used, recent biomechanical studies suggest that adding pedicle screws at the fractured level (six-screw, 6S, construct) may improve stability and clinical outcomes. However, the clinical relevance of these findings remains uncertain. Methods: A systematic review and meta-analysis were conducted in accordance with PRISMA guidelines. Three databases (Scopus, PubMed/MEDLINE, Cochrane Library) were searched for studies comparing 4S and 6S constructs in thoracolumbar fractures. Inclusion criteria encompassed comparative clinical studies reporting perioperative, functional, and radiological outcomes. Data were extracted and analyzed using Review Manager 5.4.1, applying fixed- or random-effects models based on heterogeneity. Results: Twenty-two studies involving 1595 patients were included. The 6S group showed significantly improved postoperative pain scores (VAS), better short- and long-term sagittal alignment, and a lower implant failure rate. However, this technique was associated with longer operative times, increased intraoperative blood loss, and extended hospital stays. No significant differences in long-term functional disability (ODI) or infection rates were found. Conclusions: The addition of intermediate screws improves radiological outcomes and reduces implant failure but increases surgical burden. Further high-quality studies focusing on patient-reported outcomes and specific fracture subtypes are needed to refine clinical indications.