Qiang Tang, Rong Xu, Lijun Zhang, Hua Liu, Weihong Wang
Direct comparative evidence did not demonstrate a statistically significant improvement in coronal correction under Hartung-Knapp inference, and the available data were insufficient to establish a reduction in transfusion. The correction point estimate favored traction, but the finding is exploratory and the certainty of evidence is very low because of sparse comparative data, heterogeneity, imprecision, and residual confounding. Reversible intraoperative neuromonitoring alerts should be distinguished from permanent postoperative neurological deficits.
BACKGROUND: Intraoperative traction is used during posterior spinal fusion or posterior spinal instrumentation for adolescent idiopathic scoliosis (AIS), but the comparative evidence is still limited and clinically heterogeneous. Previous reviews have also varied in whether they combined preoperative traction, traction radiographs, severe-AIS technical cohorts, and neuromonitoring studies with direct intraoperative traction-vs.-nontraction comparisons.
METHODS: This systematic review and meta-analysis followed the PRISMA 2020 statement and was registered in PROSPERO (CRD42023432276). PubMed via the National Library of Medicine, Web of Science Core Collection via Clarivate, and Embase via Elsevier were searched from inception to February 22, 2026. The core quantitative synthesis was limited to comparative AIS studies that evaluated intraoperative traction vs. no intraoperative traction during posterior spinal fusion or posterior spinal instrumentation. Severe-AIS, traction-weight, resource-utilization, and neuromonitoring studies were summarized separately. Continuous outcomes were pooled as mean differences (MDs), and dichotomous outcomes as risk ratios (RRs). Random-effects models with Hartung-Knapp adjustment were used for the primary inference.
RESULTS: Eighteen studies were included in the systematic review, and five direct comparative studies contributed to the core meta-analysis. Intraoperative traction showed a favorable but imprecise association with correction rate (4 studies; 450 participants; MD, 5.54 percentage points; 95% CI, -0.18 to 11.27; p = 0.054; I 2 = 56.3%). No clear difference was observed in number of fused levels, operative time, or blood loss. Transfusion results favored traction in direction but were based on only two studies and were very imprecise under Hartung-Knapp inference (RR, 0.48; 95% CI, 0.03-6.98). Overall complications and revision surgery showed no clear difference. Neuromonitoring events were reported more often in traction-related settings, especially with higher traction weights, larger or stiffer curves, and high-risk spinal cord morphology; most events recovered after traction reduction or release.
CONCLUSIONS: Direct comparative evidence did not demonstrate a statistically significant improvement in coronal correction under Hartung-Knapp inference, and the available data were insufficient to establish a reduction in transfusion. The correction point estimate favored traction, but the finding is exploratory and the certainty of evidence is very low because of sparse comparative data, heterogeneity, imprecision, and residual confounding. Reversible intraoperative neuromonitoring alerts should be distinguished from permanent postoperative neurological deficits.