EFFICACY, SAFETY, AND CLINICAL OUTCOMES OF BEVELED-TIP VERSUS FLAT-TIP VITRECTOMY PROBES IN PARS PLANA VITRECTOMY FOR VITREORETINAL DISEASES: A SYSTEMATIC REVIEW AND META-ANALYSIS

Introduction: Pars plana vitrectomy (PPV) is the principal procedure for vitreoretinal diseases. The beveled-tip vitrectomy probe has a port-to-tip distance approximately half that of the flat-tip probe, theoretically allowing tissue dissection closer to the retinal surface. However, comparative clinical evidence remains fragmented and has never been quantitatively synthesised. This review aimed to evaluate the efficacy (surgical efficiency), safety, and clinical outcomes of beveled-tip compared with flat-tip probes in PPV. Methods: This systematic review and meta-analysis followed PRISMA 2020. Comparative studies (RCTs, prospective/retrospective cohorts, and other comparative observational studies) in adult patients undergoing PPV with beveled-tip versus flat-tip probes were included. Risk of bias was assessed with RoB 2 and ROBINS-I. Data were pooled using a random-effects model (REML) with Hartung-Knapp-Sidik-Jonkman, DerSimonian-Laird, and fixed-effect sensitivity analyses. Certainty of evidence was rated with GRADE. Results: Seven studies (3 RCTs and 4 observational studies; 512 eyes: 271 beveled-tip and 241 flat-tip) from the United States, Hong Kong, China, and South Korea met the criteria. Beveled-tip probes were associated with a shorter total operative time (MD −4.70 minutes (95% CI −7.89 to −1.51; P = 0.004; I² = 0%); 4 studies), but not with vitrectomy time (SMD −0.03 (95% CI −0.24 to 0.19; P = 0.81; I² = 0%); 5 studies). Beveled-tip probes reduced the number of instrument exchanges (SMD −1.29 (95% CI −2.27 to −0.31; P = 0.010; I² = 92%)), endodiathermy applications (SMD −1.11 (95% CI −2.19 to −0.03; P = 0.044; I² = 92%)), and intraoperative iatrogenic bleeding (SMD −0.88 (95% CI −1.28 to −0.48; P < 0.001; I² = 0%)). There were no significant differences in iatrogenic retinal breaks (RR 0.36; 95% CI 0.05 to 2.34), hypotony (RR 1.02; 95% CI 0.32 to 3.32), recurrent retinal detachment (RD 0.00; 95% CI −0.03 to 0.03), or 6-month BCVA (MD −0.10 logMAR; 95% CI −0.29 to 0.09). A reduction in the need for sclerotomy sutures was observed only when the beveled-tip probe was also of smaller gauge (RR 0.27; 95% CI 0.19 to 0.40), not in gauge-matched comparisons (RR 1.02). The certainty of evidence was generally low to very low. Discussion: The advantage of beveled-tip probes is concentrated in the tissue-manipulation phase, namely fibrovascular membrane dissection, removal of vitreous cortex remnants, and haemostasis, rather than in the speed of core vitreous removal. These findings are consistent with laboratory flow dynamics and the shovel-and-cut technique. Interpretation is limited by confounding by gauge and cut rate, small sample sizes, a predominance of PDR populations, and data-integrity concerns in one study. Conclusion: Beveled-tip probes appear to be as safe as flat-tip probes and provide relevant intraoperative efficiency gains, particularly in diabetic vitrectomy, without differences in short-term visual outcomes. Multicentre RCTs with matched gauge and cut rate, masked outcome assessors, and standardised outcomes are needed.