Hysteroscopic myomectomy: Pearls and pitfalls from 24 years of practice

Submucous leiomyomas measuring less than 4 cm, which are generally small enough to permit hysteroscopic removal, often announce themselves by producing menorrhagia, infertility, and pregnancy wastage. Although the basic technique of hysteroscopic myomectomy, introduced by Neuwirth¹ in 1976, has remained largely unchanged, the integration of ultrasound (U/S) guidance, strict fluid monitoring, careful cervical preparation, and mechanical grasping devices² can enhance safety and efficacy while reducing the need for subsequent surgery. This article reviews both "pearls" and "pitfalls" garnered during my 24 years of experience performing more than 600 hysteroscopic myomectomies.

PEARLS

Perform diagnostic hysteroscopy in combination with U/S guidance

Technically, this combined examination is achieved by first obtaining a clear hysteroscopic view of the cavity while holding the distal lens at the internal os. As an assistant holds the tenaculum, the surgeon places the abdominal transducer in both the sagittal and transverse planes, as necessary, to obtain critical U/S measurements. The assistant's other hand allows her to freeze, measure, and store the images while the surgeon positions the hysteroscope and U/S probe for optimum views.

Use U/S guidance for hysteroscopic surgery

U/S-guided hysteroscopic surgery was reported independently by Shalev and Zuckerman⁵ and Lin et al.⁶ As a noninvasive adjuvant to resectoscopic surgery, U/S provides the operator a 3-dimensional understanding of the intrauterine pathology, taking advantage of the different echogenic characteristics of the distended bladder, myometrium, leiomyomas, and intrauterine distention fluid.

Mastering U/S-guided hysteroscopic surgery is facilitated by working with the same sonographer over time, beginning with simple cases involving grade 0 submucous myomas and progressing to more complex cases.

Establish the MAFA _limit

Hysteroscopic myomectomy has often been associated with excess fluid absorption,⁸ the results of which can be tragic. The American Association of Gynecologic Laparoscopists (AAGL) has established fluid monitoring guidelines⁹ that should be followed carefully. I favor a more stringent protocol that accounts for the patient's body mass using the formula: MAFA_limit=17.6 mL/kg.¹⁰ Both sets of guidelines establish an absolute limit of 1500 mL of low-viscosity anionic distention fluid (LVADF).¹¹

Provide adequate pressure through the fluid management system

Adequate visualization allows one to obtain a panoramic perspective of the uterus while avoiding disorientation, inadvertent uterine perforation, and incomplete removal of intrauterine pathology. These goals are dependent on both adequate intrauterine pressure and sufficient flow. Inexperienced surgeons tend to set fluid pump pressures too low, a problem that is fostered by the AAGL fluid monitoring guidelines, which state that "adequate visualization can generally be obtained with a maximum delivery pressure of 75 to 100 mm Hg."⁹ This setting is not based on randomized controlled trials and, in my opinion, it is often far below what is required for adequate visualization during hysteroscopic myomectomy. The practice of setting the pump pressure below the mean arterial pressure, first suggested by Garry et al,¹² makes little practical sense. As Loffer pointed out, the fluid deficit is the factor "that should guide the conduct of any case."¹³

I prefer to begin a case with the pump pressure at 140 to 180 mm Hg and to decrease it until the infusion pressure is at the minimum level necessary for adequate visualization. One should remember that the actual intrauterine pressure varies depending on the adjustment of the outflow port of the resectoscope. High pump pressures translate into high intrauterine pressures only when the outflow valve is shut, which is an uncommon situation during resectoscopic surgery.