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. 2025 Jul 30:12:1607323.
doi: 10.3389/fsurg.2025.1607323. eCollection 2025.

Low-density pedicle screw in adolescent idiopathic scoliosis: a systematic review and meta-analysis of 1,762 patients

Bin Zheng  1 , Qiang Zhou  2 , Xuanwen Liu  2 , Ke Ma  3 , Zhe Qiang  2
Affiliations

Low-density pedicle screw in adolescent idiopathic scoliosis: a systematic review and meta-analysis of 1,762 patients

Bin Zheng et al. Front Surg. .

Abstract

Background: High-density pedicle screws provide satisfactory correction in adolescent idiopathic scoliosis (AIS) but add to the operative time, blood loss, and cost; low-density constructs may mitigate these burdens and achieve similar correction results. Studies use inconsistent density cutoffs (most often <1.6 screws/level) and report conflicting results; therefore, we performed a systematic review and meta-analysis to clarify the clinical, radiographic, and economic impact of low screw density in patients with AIS.

Methods: A systematic review and meta-analysis were conducted following PRISMA guidelines. The PubMed, Web of Science, and Embase databases were searched until December 2024 for comparative studies. The outcomes analyzed included surgical and safety parameters (blood loss, operative time, revision rates, and complications), radiographic outcomes (Cobb angle, correction rate, and thoracic kyphosis), and implant costs. Statistical analyses were performed using RevMan 5.4, with fixed- or random-effects models applied on the basis of heterogeneity (I² threshold < 50%).

Results: Twenty-one studies comprising 1,762 patients met the inclusion criteria. Low-density screws were superior in reducing blood loss [mean difference (MD) = -88.06, P = 0.01] and operative time (MD = -22.27, P = 0.02), with no significant difference in revision rates (P = 0.78) or complications (P = 0.64). No differences were observed between the groups in the final Cobb angle (P = 0.4), Cobb correction rate (P = 0.21), or thoracic kyphosis (P = 0.43). The per-level implant cost was lower (standard mean difference = -1.32, P < 0.00001) in the low-density group.

Conclusion: Compared with high-density screws, low-density pedicle screws provide comparable radiographic and safety outcomes while reducing the operative time, blood loss, and cost. These findings support the use of low-density constructs in AIS surgery, although the variability in study designs and screw density definitions warrants further research. Future multicenter randomized controlled trials are needed to refine the optimal screw density strategies for treating AIS.

Systematic review registration: https://www.crd.york.ac.uk/PROSPERO/view/CRD420251088403, PROSPERO CRD420251088403.

Keywords: adolescent idiopathic scoliosis; deformity; high density; low density; screw density.

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Conflict of interest statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Figures

Figure 1
Figure 1
Flowchart of study selection.
Figure 2
Figure 2
Risk of bias of the RCTs.
Figure 3
Figure 3
Comparison of blood loss in the low-density and high-density groups.
Figure 4
Figure 4
Comparison of the operative time between the low-density and high-density groups.
Figure 5
Figure 5
Comparison of revision surgeries in the low-density and high-density groups.
Figure 6
Figure 6
Comparison of complications between the low-density and high-density groups.
Figure 7
Figure 7
Comparison of the Cobb angle between the low-density and high-density groups.
Figure 8
Figure 8
Comparison of major curves of correction in the low-density and high-density groups.
Figure 9
Figure 9
Comparison of thoracic kyphosis between the low-density and high-density groups.
Figure 10
Figure 10
Comparison of cost per level in the low-density and high-density groups.
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