Clinical Performance of Digital Microscopes in Microsurgery: A Retrospective Analysis of Operative Time and Intraoperative/Postoperative Thrombosis Rates.

Abstract

Digital microscopes (DMs) have been increasingly adopted in microsurgery; however, clinical evidence regarding their operative efficiency, safety, and learning curve compared with conventional optical microscopes (OMs) remains limited. In particular, anastomosis-specific operative time and intraoperative thrombosis-an indicator closely related to technical precision-have not been sufficiently evaluated in clinical settings. Therefore, this study aimed to evaluate the learning curve associated with digital microscope adoption in microsurgical reconstruction using operative time metrics and to assess thrombotic events as exploratory safety outcomes. We retrospectively reviewed 123 consecutive free-flap reconstructions performed by three experienced plastic surgeons between June 2022 and March 2025. The cases were categorized into three groups: OM, early-phase DM (DM-T1), and late-phase DM (DM-T2). The choice of visualization system was determined by operating room availability rather than surgeon preference. Microscope usage time, arterial and venous anastomosis times, and intraoperative and postoperative arterial or venous thromboses were analyzed. Intraoperative arterial patency was assessed by palpation and pinprick tests, and venous patency was assessed by the patency test. Learning curve effects were evaluated by comparing DM-T1 and DM-T2. The number of cases in each group was 37, 34, and 52 in the DM-T1, DM-T2, and OM groups, respectively. Mean microscope usage time was longer in DM-T1 than in DM-T2 and OM (71.9 ± 15.0 vs. 57.6 ± 13.4 vs. 58.5 ± 19.8 min; p = 0.0055 and p = 0.0021). Mean arterial anastomosis time was also longer in DM-T1 compared with DM-T2 and OM (22.5 ± 7.2 vs. 19.0 ± 5.1 vs. 17.4 ± 4.9 min; p = 0.048 and p = 0.0028). Venous anastomosis time showed a decreasing trend from DM-T1 to DM-T2 but did not reach statistical significance. The incidence of intraoperative and postoperative thrombosis did not differ among groups (intraoperative arterial thrombosis: 18.9%, 14.7%, and 15.4% in the DM-T1, DM-T2, and OM groups, respectively; p ≥ 0.05). DM demonstrates a measurable learning curve, with operative efficiency improving to levels comparable to those of OM, while maintaining similar thrombotic safety. DMs are a reliable visualization platform for microsurgical reconstruction.