Hysteroscopic myomectomy with the IBS® Intrauterine Bigatti Shaver: A Retrospective Comparative Analysis of the impact of rotational speed and aspiration flow rate.

Background: Myoma removal remains a challenge hysteroscopically including for the "IBS®" Intrauterine Bigatti Shaver technique. Objective: To evaluate whether the Intrauterine IBS® instrument settings and the myoma size and type are prognostic factors for the complete removal of submucous myomas using this technology. Materials and Methods: This study was conducted at the San Giuseppe University Teaching Hospital Milan, Italy; Ospedale Centrale di Bolzano - Azienda Ospedaliera del Sud Tirolo Bolzano, Italy (Group A) and the Sino European Life Expert Centre-Shanghai Jiao Tong University School of Medicine Affiliated Renji Hospital, Shanghai, China (Group B). In Group A: surgeries were performed between June 2009 and January 2018 on 107 women using an IBS device set to a rotational speed of 2,500 rpm and an aspiration flow rate of 250ml/min. In Group B: surgeries were performed between July 2019 and March 2021 on 84 women with the instrument setting to a rotational speed of 1,500 rpm and aspiration flow rate of 500 ml/min. Further subgroup analysis was performed based on fibroid size:<3 cm and 3-5 cm. Both Groups A and B were similar in terms of patient age, parity, symptoms, myoma type and size. Submucous myomas were classified according to the European Society for Gynaecological Endoscopy classification. All patients underwent a myomectomy with the IBS® under general anaesthesia. The conventional 22 Fr. Bipolar Resectoscope was used in cases requiring conversion to the resection technique. All surgeries were planned, performed and followed by the same surgeon in both institutions. Main outcome measures: Complete resection rates, total operation time, resection time and used fluid volume. Results: Complete resection with the IBS® Shaver was seen in 93/107 (86.91%) in Group A versus 83/84 (98.8 %) in Group B (P=0.0021). Five patients (5.8%) in Subgroup A1 (<3 cm) and nine patients (42.9%) in Subgroup A2 (3cm~5cm) could not be finished with the IBS (P<0.001, RR=2.439), while in Group B only one case (8.3%) in Subgroup B2 (3cm~5cm) underwent a conversion to bipolar resectoscope (Group A: 14/107=13.08% vs. Group B: 1/84=1.19%, P=0.0024). For <3cm myomas (subgroup A1 versus B1) there was a statistically significant difference in terms of resection time (7.75±6.363 vs. 17.28±12.19, P<0.001), operation time (17.81 ± 8.18 vs. 28.19 ±17.614, P<0.001) and total amount of fluid used (3365.63 ± 2212.319 ml vs. 5800.00 ± 8422.878 ml, P<0.05) in favour of Subgroup B1. For larger myomas, a statistical difference was only observed for the total operative time (51.00±14.298 min vs. 30.50±12.122 min, P=0.003). Conclusion: For hysteroscopic myomectomy using the IBS®, 1,500rpm rotational speed and 500ml/min aspiration flow rate are recommended as these settings result in more complete resections compared to the conventional settings. In addition, these settings are associated with a reduction in total operating time. What is new?: Reducing the rotational speed rate from 2500 rpm to 1500 rpm and increasing the aspiration flow rate from 250 ml/min to 500 ml/min improve complete resection rates and reduce operating times.