Parallel-bar versus cross-bar configurations in the Nuss procedure: a systematic review and meta-analysis

Pectus excavatum (PE) represents the most prevalent congenital deformity of the chest wall, and minimally invasive repair of pectus excavatum (MIRPE) continues to evolve in pursuit of improved correction and reduced morbidity. Both cross-bar (CB) and parallel-bar (PB) configurations are widely adopted, yet comparative data remain limited. This systematic review and meta-analysis evaluated perioperative outcomes and postoperative efficacy of CB versus PB techniques.

Following PRISMA 2020 guidelines, PubMed, Embase, and the Cochrane Library were searched through October 24, 2025. Studies directly comparing CB and PB and reporting at least one predefined outcome were eligible. Pooled odds ratios (ORs) and mean differences (MDs) were estimated using a random-effects model based on the DerSimonian-Laird method. Risk of bias was evaluated using Risk of Bias In Non-randomized Studies of Interventions tool (ROBINS-I), and the certainty of evidence was graded according to Grading of Recommendations, Assessment, Development, and Evaluation (GRADE).

Among the 1,021 patients analyzed, 449 underwent CB repair and 572 PB repair. Operative time [MD 4.79 min; 95% confidence interval (CI): -6.27 to 15.85] and length of hospital stay (MD 0.24 days; 95% CI: -0.39 to 0.88) did not differ significantly between techniques. Rates of pleural effusion [4.6% vs. 1.3%; odds ratio (OR) 3.59; 95% CI: 0.82-15.72] and pneumothorax (2.5% vs. 2.3%; OR 1.08; 95% CI: 0.39-2.97) were comparable between CB and PB. CB was associated with a small but statistically significant improvement in postoperative Haller Index (MD -0.10; 95% CI: -0.17 to -0.03). Sensitivity analyses revealed study-driven heterogeneity for operative time and hospital stay. Overall risk of bias ranged from moderate to serious, with low to very low certainty of evidence across outcomes.

CB and PB techniques demonstrate equivalent perioperative profiles and complication rates in MIRPE.