Supplementary Material for: Quincke versus diamond-tip needles for entry in placental laser surgery for twin-to-twin transfusion syndrome

\ Introduction: Chorioamnion separation (CAS), preterm prelabor rupture of membranes (PPROM), and preterm delivery (PTD) remain major complications of fetoscopic laser photocoagulation (FLP) for twin-to-twin transfusion syndrome (TTTS). We sought to examine whether use of quincke-tip needles for initial entry in FLP reduces the risk of these complications. Methods: This is a secondary analysis of prospectively collected data from patients that had FLP for TTTS at a single tertiary care center (2011 – 2021). We excluded patients for whom direct trocar entry was used. Patients for whom a quincke-tip needle, versus a diamond-tip needle was used for Seldinger entry were compared. Demographics, ultrasound findings and operative characteristics were compared between groups. Post-operative outcomes and complications (including CAS, PPROM and PTD) were also compared. Multivariate logistic regression models were fit to assess independent risk factors for complications. Results: 386 patients met inclusion criteria; quincke-tip needles were used in 81 (21.0%) cases while diamond-tip needles were used in 305 (79.0%). Rates of CAS (11.1% vs 9.5%, p = 0.67) and PPROM (44.4% vs 41.0%, p = 0.57) were similar between groups. Patients in the quincke-tip group delivered 1.5 weeks earlier than those in the diamond-tip group (30.5 vs 32.0 weeks, p = 0.01). However, these patients were more likely to be delivered for maternal (35.9% vs. 19.0%) and fetal (23.1% vs. 15.3%) indications (p < 0.01). In multivariate analysis, needle type was not identified as an independent risk factor for PPROM. However, quincke-tip needle use was associated with PTD less than 32 weeks (aOR 1.83, 95% CI 1.01 – 2.95, p = 0.046). Discussion/Conclusion: Membrane complications following FLP did not depend on needle type. Earlier delivery in quincke-tip group was likely attributable to higher rates of maternal and fetal delivery indications. The needle chosen for entry is probably best determined by operator preference.