A novel hysteroscopic myomectomy strategy based on RoBEEM (Roller ball Enucleation followed by Excision Method): Integration of adjunctive techniques to expand TCR indications.

Shigeo Inoue: Writing – review & editing, Writing – original draft, Methodology, Investigation, Conceptualization. Mamoru Urabe: Writing – review & editing, Resources, Investigation.

This study was conducted in accordance with the ethical standards of the institution. Formal review by the institutional review board was not required because patients provided general consent for the use of clinical data in academic publications.

No external funding was received for this study.

A total of 631 procedures were performed in 613 patients ( Table 1 ). The median patient age was 44 years (22–56 years). FIGO classification included 11 type 0, 120 type 1, 447 type 2, and 53 type 3 myomas. Table 1 Patient and Myoma Characteristics. Item Value Number of procedures 631 Number of patients 613 Median age (years) 44 Myoma type (FIGO): Type 0 11 Myoma type (FIGO): Type 1 120 Myoma type (FIGO): Type 2 447 Myoma type (FIGO): Type 3 53 Patient and Myoma Characteristics. Complete resection in a single session was achieved in 576 of 631 procedures (91.2%). The remaining 55 procedures were not completed in a single session; among these, 11 underwent repeat TCR, 3 underwent hysterectomy, and 1 underwent laparoscopic myomectomy. The remaining 40 required no additional surgical intervention. Among the 53 type 3 myomas, complete resection in a single session was achieved in 47 (88.7%). The median operative time was 73 min (12–192 min), median myoma diameter immediately before surgery was 5.2 cm (2.0–13.3 cm), and median resected myoma weight was 76 g (20–407 g) ( Table 2 ). A scatter plot of myoma weight versus operative time is shown in Fig. 2 . Table 2 Operative and Clinical Outcomes. Item Value Median operation time (min) 73 Median myoma diameter (cm) 5.2 Median myoma weight (g) 76 One-stage completion rate 91.2% Completion rate for type 3 88.7% Fig. 2 (A) Scatter plot showing a positive correlation between myoma weight and operation time, reflecting the increased surgical burden associated with larger myomas. (B) Scatter plot showing that operation time per gram (min/g) decreased with increasing myoma weight, indicating greater resection efficiency for larger myomas. Operative and Clinical Outcomes. (A) Scatter plot showing a positive correlation between myoma weight and operation time, reflecting the increased surgical burden associated with larger myomas. (B) Scatter plot showing that operation time per gram (min/g) decreased with increasing myoma weight, indicating greater resection efficiency for larger myomas. Median tissue removal efficiency was 1.10 g/min overall. Efficiency was significantly higher in myomas weighing ≥ 76 g than in those weighing < 76 g (1.44 vs. 0.98 g/min, p < 0.001) and varied according to myoma type, being highest in prolapsed (2.56 g/min) and cervical myomas (1.65 g/min) and lowest in fundal myomas (0.96 g/min) ( Table 3 , Fig. 2 ). Table 3 Median Tissue Removal Efficiency by Weight Group and Myoma Type. Category Tissue Removal Efficiency (g/min) All cases 1.10 By weight group < 76 g 0.98 ≥ 76 g 1.44 By myoma type Prolapsed myoma 2.56 Cervical myoma 1.65 Type 3 1.01 Fundal myoma 0.96 Median Tissue Removal Efficiency by Weight Group and Myoma Type. All patients presented with menorrhagia, which improved postoperatively. At 3-month follow-up, transvaginal ultrasonography confirmed complete removal in cases judged complete at surgery. Uterine perforation occurred in 13 procedures (11 during loop resection and 2 during cervical dilation with Hegar), all repaired laparoscopically. No perforations occurred during roller ball dissection. Cervical lacerations were minor and required no suturing. An irrigation fluid deficit exceeding 1500 mL was observed in 7 procedures, and serum sodium levels below 120 mmol/L occurred in 5 cases. Two patients experienced significant intraoperative bleeding, and three developed postoperative infection; all were managed conservatively ( Table 4 ). Table 4 Postoperative Events and Complications. Event Cases Reported pregnancies 15 Reported deliveries 8 Uterine perforation 13 Fluid overload (>1500 mL) 7 Severe hyponatremia (<120 mmol/L) 5 Massive bleeding requiring transfusion 2 Postoperative infections 3 Postoperative Events and Complications. The following cases demonstrate the applicability of RoBEEM to myomas traditionally considered unsuitable for hysteroscopic resection. Corresponding surgical videos (Video 1 and Video 2) and pre- and postoperative MRI findings provide objective documentation of the procedures and outcomes. A 50-year-old woman with a 9.5 cm cervical myoma underwent RoBEEM after preoperative GnRH analog therapy. Because complete detachment of the base was difficult, repeated cycles of dissection and resection were performed. The resected weight was 394 g, with a resection efficiency of 2.20 g/min. MRI obtained 5 months postoperatively confirmed complete disappearance of the myoma ( Fig. 3 ). Fig. 3 Case 1. Posterior cervical myoma. a. 50-year-old woman with a 9.5 cm posterior cervical myoma. b. Posterior MPC interface exposed, c. Loop set for centripetal resection. d. Resected weight: 394 g, Efficiency: 2.20 g/min. e. MRI at 5 months: Myoma resolved, posterior myometrium restored. Case 1. Posterior cervical myoma. a. 50-year-old woman with a 9.5 cm posterior cervical myoma. b. Posterior MPC interface exposed, c. Loop set for centripetal resection. d. Resected weight: 394 g, Efficiency: 2.20 g/min. e. MRI at 5 months: Myoma resolved, posterior myometrium restored. A 23-year-old nulligravid woman with a 5.1 cm FIGO type 3 myoma underwent complete hysteroscopic resection using the single-incision enucleation approach. The procedure was completed in 105 min without complications. She subsequently conceived spontaneously and delivered vaginally at term ( Fig. 4 ). Fig. 4 Case 2. FIGO type 3 myoma. a. Preoperative MRI b. Single endometrial incision using a loop electrode. c. MPC interface identified; roller ball electrode inserted for thumbing dissection. d. Centripetal resection of myoma from dissected plane. e. Myoma removed; intact MPC clearly visible. f. Postoperative MRI. Case 2. FIGO type 3 myoma. a. Preoperative MRI b. Single endometrial incision using a loop electrode. c. MPC interface identified; roller ball electrode inserted for thumbing dissection. d. Centripetal resection of myoma from dissected plane. e. Myoma removed; intact MPC clearly visible. f. Postoperative MRI.

This retrospective study analyzed 631 TCR procedures for submucosal myomas ≥ 4 cm in diameter or with a resected myoma weight ≥ 35 g, selected from 1945 TCR procedures performed at Sano Hospital between January 2016 and December 2024. At our institution, patients with suspected uterine malignancy based on preoperative clinical and imaging findings are referred to specialized centers for abdominal hysterectomy and are not considered candidates for TCR. For patients with benign submucosal myomas, including FIGO type 3 lesions, TCR is offered irrespective of myoma size or residual myometrial thickness. After receiving an explanation of all appropriate treatment options, including TCR and laparoscopic surgery, patients who elected hysteroscopic treatment underwent RoBEEM. During the study period, all TCR procedures were performed by a single surgeon using the standardized RoBEEM technique. The study period was limited to the era after complete implementation of the electronic medical record system to ensure consistent data retrieval. A total of 613 patients underwent 631 procedures, including repeated surgeries in some cases. Preoperative MRI was performed in all cases to determine myoma location and FIGO classification. All patients received gonadotropin-releasing hormone (GnRH) analog therapy. Myoma diameter was measured by transvaginal ultrasonography immediately before surgery, and the weight of the resected myoma(s) was recorded postoperatively. Patient age, operative time, completeness of resection, and perioperative outcomes were analyzed. In patients with multiple myomas, FIGO classification and myoma diameter were determined according to the largest lesion, whereas the total weight of all resected myomas was recorded. Histopathological examination confirmed leiomyoma in all cases; 22 cases showed concomitant adenomyosis. Endometrial ablation was performed concurrently in 43 procedures. A 24 Fr single-sheath resectoscope (OLYMPUS monopolar system or TCRis saline bipolar system) was used with monopolar loop (A22201C) and roller ball (A22251C) electrodes or TCRis loop (WA22503D) and roller ball (WA22351C) electrodes. The distension medium was 3% D -sorbitol solution for the monopolar system and normal saline for the TCRis system. Continuous irrigation was achieved by gravity flow with an approximately 80 cm height difference and manual inflow adjustment, without automated pumps. A synthetic hygroscopic cervical dilator (Lamiken-R, 3 mm) was inserted preoperatively, followed by oral misoprostol 200 µg to further soften and dilate the cervix. Under general anesthesia, the cervix was dilated to Hegar size 17 (14 mm). This degree of dilation permitted passive outflow between the sheath and cervix, enabling single-sheath continuous irrigation (SSCI) without an outer sheath. In TCR, dissection, excision, and hemostasis were performed using continuous reciprocal forward and backward movement of the electrode, controlled by the surgeon’s thumb positioned on the thumb ring of the resectoscope handle. This maneuver was designated as “thumbing” and was employed consistently throughout the procedure. Using a roller ball electrode in low-output coagulation mode, the myoma was dissected around its base with thumbing. In type 0 and prominent type 1 myomas, this maneuver often achieved complete enucleation. In type 2 myomas, removal of the overlying endometrium allowed entry into the plane between the myoma and its MPC, enabling circumferential dissection. Once exposed, the loop electrode was inserted beneath the myoma, and centripetal cutting was performed toward the uterine center ( Fig. 1 ). Fig. 1 RoBEEM and Beak-Loop Picking Technique. Schematic representation of the Roller ball Enucleation followed by Excision Method (RoBEEM), illustrating its three essential steps. (1) Blunt dissection is initiated at the rising margin of the myoma, separating it from the surrounding myometrium along the pseudocapsule using a roller ball electrode with low-output coagulation (“thumbing” maneuver). (2) Centripetal slicing is performed with a loop electrode toward the uterine cavity, starting from the dissected plane. (3) The sliced fragment is extracted under direct vision by grasping it between the loop and the beak of the resectoscope—referred to as the "beak-loop picking technique." RoBEEM and Beak-Loop Picking Technique. Schematic representation of the Roller ball Enucleation followed by Excision Method (RoBEEM), illustrating its three essential steps. (1) Blunt dissection is initiated at the rising margin of the myoma, separating it from the surrounding myometrium along the pseudocapsule using a roller ball electrode with low-output coagulation (“thumbing” maneuver). (2) Centripetal slicing is performed with a loop electrode toward the uterine cavity, starting from the dissected plane. (3) The sliced fragment is extracted under direct vision by grasping it between the loop and the beak of the resectoscope—referred to as the "beak-loop picking technique." In contrast, for type 3 or deeply embedded myomas, the overlying endometrium must be incised using a loop or needle electrode to expose the myoma and access the MPC. This Single-Incision Enucleation Method enables entry of the roller ball electrode and dissection via thumbing. For fertility-preserving procedures, this approach was also used for type 2 myomas to minimize endometrial defect. Large myomas were removed by repeating cycles of dissection and excision. After enucleation, the loop electrode was guided along the exposed myoma surface while the resectoscope was drawn toward the operator to obtain long, thick slices; this maneuver was designated as the thumbing carve method. The broad myoma surface created by prior dissection facilitated efficient tissue slicing. Continuous thumbing ensured firm embedding of the loop within the myoma. The sliced fragment was then captured between the loop and the beak of the scope and withdrawn under direct visualization, referred to as the beak-loop picking technique. This approach prevented blind intrauterine manipulation and reduced unnecessary resection of previously excised tissue ( Fig. 1 ). Under hysteroscopic visualization, the myoma base was identified and dissected with a roller ball electrode to the extent necessary to permit forceps traction. In cervical myomas, traction allowed descent toward the external os, after which the protruding portion was divided under direct vision using scissors. In prolapsed myomas already extending beyond the external os, the base was first detached hysteroscopically, followed by division under direct vision. After removal, the residual base was inspected hysteroscopically, and any remaining tissue was resected and hemostasis achieved.

RoBEEM achieved a high rate of single-session complete resection for large or complex submucosal myomas, including lesions traditionally considered unsuitable for conventional TCR. Our findings indicate that RoBEEM can broaden the practical applicability of hysteroscopic myomectomy, allowing appropriately selected patients who would otherwise undergo laparoscopic or open surgery to be managed hysteroscopically.

This study demonstrated high resection efficiency with RoBEEM in combination with a systematic set of operative strategies. When patients were divided into two groups by resected weight (≥ 76 g vs. < 76 g), resection efficiency was significantly higher in the heavier group (1.44 vs. 0.98 g/min, p < 0.001). These findings do not support the traditional assumption that larger myomas necessarily require proportionally longer procedures. The high resection efficiency observed in larger myomas is considered to result primarily from the RoBEEM technique and subsequent centripetal slicing. Blunt dissection with a roller ball electrode exposed a broad surface of the myoma, allowing long, thick sections to be excised in a single stroke. Unlike conventional TCR, which often involves inefficient “double-cutting” due to tissue fragmentation and limited stroke range, RoBEEM enabled a wider cutting arc and deeper, directed excision from the enucleated plane toward the uterine center. The thumbing carve method further improved efficiency by embedding the loop electrode deeply while drawing the resectoscope toward the operator ( Fig. 1 ). Several adjunctive techniques were considered important contributors to the efficiency of the proposed method. First, cervical dilation to a diameter of 14 mm enabled passive outflow between the sheath and cervical canal, allowing SSCI to be achieved without an outer sheath or automated irrigation pump. In our experience, this setup provided a consistently clear operative field while improving instrument maneuverability without the need for a double-sheath system or automated irrigation pump. Second, the thumbing technique was consistently used for dissection, excision, and coagulation. During dissection in particular, it enabled stable electrode contact with the myoma surface, facilitating controlled tissue separation. Finally, the beak-loop picking technique allowed sliced fragments to be removed under direct visualization, reducing tissue accumulation and preventing redundant resection. Several prior techniques have sought to improve hysteroscopic myomectomy by initiating dissection before resection. Mazzon et al. proposed the cold loop technique, which uses a non-energized loop to bluntly dissect the myoma from its MPC. [3] Litta and Saccardi introduced a needle-type electrode for precise MPC dissection, [4] and Lin developed the LIN cutting loop, a unipolar device capable of both cutting and dissecting. [5] These techniques pioneered separation of the myoma from the surrounding myometrium before resection and improved procedural safety. However, these methods relied predominantly on straight or nearly straight instruments, which may be suboptimal for curved myoma surfaces. In contrast, RoBEEM employs a rotatable roller ball electrode with an angled shaft, allowing the tip to remain aligned with the myoma surface even beyond the maximal diameter of the nodule. Unlike the cold loop technique, the roller ball electrode also permits seamless transition between low-power dissection, blunt mechanical dissection without current when appropriate, and immediate coagulation for hemostasis without changing instruments. This design facilitates controlled sub-MPC dissection while permitting simultaneous hemostasis when required. [1] , [2] , [6] , [7] RoBEEM also demonstrated higher tissue removal efficiency (1.10 g/min) than the techniques reported by Wang et al. (0.59 g/min) [8] and Lin et al. (0.65 g/min). [5] While Mazzon et al. recently reported removal of a single 2.9 cm FIGO type 3 myoma using multiple endometrial incisions, [9] RoBEEM achieved complete resection in 47 of 53 type 3 myomas (88.7%; median diameter, 5.2 cm) using a Single-Incision Enucleation approach, and two patients subsequently achieved spontaneous pregnancy and delivery. These findings indicate that RoBEEM broadens the practical applicability of hysteroscopic myomectomy to complex submucosal myomas traditionally considered unsuitable for conventional TCR, while preserving the uterus in appropriately selected patients. According to the classification proposed by Lasmar et al., a low protrusion rate is a major factor indicating the difficulty of TCR. [10] RoBEEM effectively increased the functional protrusion of the myoma and reduced the practical limitations represented by the Lasmar classification. Consequently, many lesions initially considered unsuitable for hysteroscopic resection became candidates for TCR. RoBEEM was successfully applied in myoma types traditionally considered difficult for hysteroscopic management, including type 3 myomas, deeply embedded myomas (i.e., intramural myomas that had lost endometrial protrusion after GnRH analog therapy or became buried under irrigation pressure during hysteroscopy), cervical myomas, myomas with thin surrounding myometrium, and prolapsed submucosal myomas. [1] , [2] , [6] , [7] , [11] Deeply embedded lesions were approached using the Single-Incision Enucleation technique. A limited endometrial incision exposed the myoma and allowed access to the MPC, followed by roller ball dissection and centripetal resection. In cases with extremely thin surrounding myometrium, particularly near the serosa, resection was initiated from the myoma surface already separated from the MPC, thereby reducing the risk of perforation while maintaining surgical precision. Cervical myomas, often regarded as particularly challenging because of limited operative space and thin outer myometrial layers, were also effectively managed with RoBEEM. Anatomically, the cervix contains predominantly collagen with relatively sparse smooth muscle, except for a circumferential muscular ring around the internal os. [12] In contrast, the uterine corpus contains well-developed spiral and circular muscle bundles. [13] These anatomical differences may explain the consistently facile sub-MPC dissection observed in cervical myomas. Once mobilized, the proximity of the vagina facilitated direct-vision management using conventional instruments. Notably, tissue removal efficiency in cervical myomas (1.65 g/min) exceeded that of uterine body myomas. Similarly, prolapsed submucosal myomas could be managed effectively using the principles of RoBEEM. Mobilization and direct-vision removal were readily achieved, contributing to the highest tissue removal efficiency among all myoma types (2.56 g/min). Hysteroscopic myomectomy carries inherent risks, including uterine perforation, fluid overload, bleeding, and infection. In this study, uterine perforation occurred in 13 of 631 procedures (2.1%), all of which were managed laparoscopically. Importantly, all perforations occurred either during cervical dilation (2 cases) or loop resection (11 cases); none occurred during roller ball dissection. This finding supports the hypothesis that blunt dissection within the MPC reduces the risk of unintended penetration beyond the myoma. Unlike the cold loop technique, RoBEEM employs a roller ball electrode that permits low-power electrosurgical dissection while maintaining the option of blunt mechanical dissection without current when appropriate. The same instrument also allows immediate coagulation for hemostasis without exchanging devices. For women undergoing fertility-preserving surgery, the option of blunt dissection without electrosurgical current, when appropriate, may further minimize thermal injury to the myometrial pseudocapsule (MPC), endometrium, and surrounding myometrium. Overall, RoBEEM achieved a high one-stage completion rate with a low incidence of major complications in this consecutive case series. The reproducibility of RoBEEM was further explored in an independent series of 47 procedures performed by co-author Urabe. Median resected myoma weight was 47.5 g, operative time was 137.5 min, and tissue removal efficiency was 0.47 g/min. No perforations occurred during roller ball dissection, although one perforation occurred during loop resection. Two cases of water intoxication and six transfusions were reported. While outcomes were less favorable than in the present series, differences in perioperative management, patient selection, and surgeon experience may have contributed. Nevertheless, successful application of RoBEEM at another institution provides preliminary support for the reproducibility and broader applicability of the technique.

During the preparation of this work the author(s) used ChatGPT (OpenAI) in order to revise and improve English expression and ensure grammatical accuracy. After using this tool, the author(s) reviewed and edited the content as needed and take(s) full responsibility for the content of the published article.

Transcervical resection (TCR) has gained widespread acceptance as a minimally invasive treatment for submucosal myomas with high protrusion into the uterine cavity. However, FIGO type 2 myomas, which are the most common type requiring intervention due to symptoms such as menorrhagia and infertility, are often considered unsuitable for hysteroscopic resection unless they are small. Many such cases have been managed by laparotomy or laparoscopy, and hysterectomy has been performed. To address these limitations, the author developed the Roller ball Enucleation Followed by Excision Method (RoBEEM), conceptually based on the centripetal cutting method previously reported. [1] This method involves dissecting the myoma pseudocapsule (MPC) with a rotatable roller ball electrode and subsequently resecting the exposed myoma tissue centripetally with a loop electrode, facilitating complete resection of large or deeply located myomas while minimizing injury to the surrounding myometrium and endometrium. Several adjunctive strategies—such as single-sheath continuous irrigation (SSCI), thumbing-based instrument control, and slice-by-slice fragment removal—were incorporated to enhance procedural efficiency, visualization, and reproducibility. This study aimed to evaluate the combined effectiveness of these interrelated techniques.

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.