Submucosal myomas, through anatomic distortion of the uterine cavity, are implicated in the genesis of heavier menstrual bleeding, and as an independent risk factor for infertility and pregnancy loss. For more than 3 decades, gynecologic surgeons have been performing hysteroscopic resection of submucous myomas in order to avoid more substantial and morbid, yet traditional and effective approaches such as laparotomy and hysterotomy. As for most surgeries, one of the most critical considerations of this option remains patient selection.

Expert hysteroscopists have described well-established parameters to help guide surgeons in choosing which patient will experience a more favorable outcome, which include: older age, uterine size ≤ 6 cm, myoma size ≤ 3 cm, and projected operating time less than 20 minutes. Various classifications have been proposed to assess the feasibility of a hysteroscopic myomectomy (Boxes 27.1 and 27.2), although the classification originally proposed by Wamsteker and colleagues is the most commonly used. The hysteroscopic approach to myomectomy is primarily appropriate for submucous myomas with a majority, that is, >50% (types 0 or I), of their volume protruding into the uterine cavity, a ratio that can be increased somewhat by preoperative treatment with gonadotropin-releasing hormone agonist (GnRH-a) treatment (see below). To venture outside of these basic guidelines or beyond self-recognized hysteroscopic experience invites not only greater risk of perioperative complications, but reduced efficacy of the procedure itself.

Various methods of resecting submucosal fibroids have been described using different energy modalities (Nd:YAG, monopolar and bipolar electrosurgical techniques, hysteroscopic scissors, and mechanical resectoscopes) with accommodating fluid distention media. All have their inherent advantages and potential risks to patients. Ultimately, the surgeon’s knowledge and experience with each of these should dictate their use in the setting of both basic and complex procedures.

Working in a confined space such as the endometrial cavity can pose many challenges, and a good understanding of these opposing forces will allow for a more successful outcome. Such variables include the number, size, and exact location of the fibroids as well as the parity of the patient and whether she has been instrumented in the past or suffered from infectious processes.

It is critical for the surgeon to have an accurate three-dimensional understanding of the uterine anatomy and its myomas prior to undertaking the surgery. Although transvaginal ultrasound is an effective assessment tool for women with abnormal uterine bleeding, further evaluation is often warranted prior to operative hysteroscopy. Sonohysterography has become an effective office-based tool, which can clearly delineate intracavitary lesions, although in recent years office hysteroscopy has become more commonplace, providing a clear view of the lesion that will facilitate operative planning.
A less obvious advantage of sonohysterography is the ability to detect the percentage of the fibroid that is intramural. Type II myomas (≥50% intramural) are not only more difficult to resect and should only to be approached by skilled surgeons, but also have a higher probability of requiring secondary procedures.

Magnetic resonance imaging, which provides high resolution of soft tissues, remains an alternative preoperative imaging modality, especially for evaluating for other fibroids that may affect the surgeon’s surgical approach. Historically, the use of hysterosalpingography has been described for the preoperative assessment of the uterine cavity, although its value has lessened considerably, with the introduction of the above imaging techniques, which avoid radiation exposure and offer fewer risks, especially if tubal patency is not in question.

Timing of the procedure is another aspect that requires careful consideration, since a relatively atrophic endometrial lining with the least amount of shedding or bleeding makes for an easier procedure. The use of preprocedural suppression with oral contraceptive pills or continuous progestins is generally sufficient if it
is difficult to schedule the procedure in the early proliferative phase of the menstrual cycle, or the patient has unpredictable bleeding patterns.

GnRH analogue are effective in reducing the volume of the uterus and associated myomas, although less so for submucous myomas, in the short term. In the preoperative preparation of patients with submucous myomas, treatment with a GnRH analogue will assist in reducing the vascularity of the myometrium and the risk of intraoperative bleeding. In addition, because GnRH analogue treatment reduces normal myometrial volume to a greater degree than it reduces the volume of submucous myomas, assisting in extruding these myomas more clearly into the uterine cavity and facilitating resection. Two to three months of preoperative therapy with GnRH analogue is typically required (e.g., leuprolide 3.75 mg/month). As these agents have a stimulatory effect on endometrial activity in the first 2 to 3 weeks after administration, hysteroscopy should be avoided during this period of time.

Preoperative cervical ripening with vaginal prostaglandins or laminaria may be useful in nulliparous women or those at risk for cervical stenosis, as evident on office examination. Most resectoscopes are at least 9 mm in diameter and require significant cervical dilation in most patients, which if made easier, reduce the potential risk of cervical injury and uterine perforation. Following is a brief description of the surgical procedure used (see also video: Hysteroscopic Myomectomy).

1. Patient positioning and preparation, and instrument selection and placement: Patients are placed in lithotomy position; Trendelenburg positioning should be avoided. Lingual mask airways are frequently selected by anesthesiologists, but in morbidly obese patients, in whom airway occlusion is a concern, endotracheal intubation should be considered. After examination under anesthesia, a side-opening bivalve speculum is placed in the vagina and the cervix identified. After placing a single tooth tenaculum along the anterior lip of the cervix, the cervix is infiltrated with 10 cc dilute vasopressin (20 U diluted in 50 cc normal saline) with a 22G spinal needle at the 4 o’clock and 8 o’clock positions, to reduce the risk of bleeding, and moreover, distention fluid intravasation. The needle is advanced approximately 1 cm into the cervical stroma and the solution slowly injected. The anesthesiologist should be informed whenever using vasoactive agents, which carry well-described cardiovascular risks.

The cervix is then dilated with a series of Hanks or Pratt dilators up to a diameter sufficient to accommodate the 9-mm outer sheath of a standard resectoscope. We prefer those longer dilators that have a gradually tapered tip, minimizing the need for forceful advancement and the risk of perforation. Most continuous-flow resectoscopes use endoscopes with a 12° lens, providing a more in-line view of the operation. The surgeon should be familiar with the specific resectoscope being used, be able to assemble it, select the power settings, and problem solve issues that may arise.