Diagnostic and Operative Hysteroscopy: Polypectomy, Myomectomy, and Endometrial Ablation

Published on 11/04/2015 by admin

Filed under Surgery

Last modified 11/04/2015

Print this page

rate 1 star rate 2 star rate 3 star rate 4 star rate 5 star
Your rating: none, Average: 0 (0 votes)

This article have been viewed 3583 times

Chapter 42 Diagnostic and Operative Hysteroscopy: Polypectomy, Myomectomy, and Endometrial Ablation

INTRODUCTION

Hysteroscopy is an accurate surgical approach for evaluating the uterine cavity and treating a multitude of abnormalities. At its essence, it involves the transcervical placement of a lens and light system into the uterine cavity while using gas or liquid for distension of the cavity. Modern hysteroscopy is performed almost exclusively with the addition of a camera and video monitoring system. Operative hysteroscopy is performed using an electrosurgical resectoscope or a sleeve with an operating channel to accommodate instruments for grasping, biopsying, or cutting with scissors or laser.

Today, in addition to being an excellent diagnostic technique, hysteroscopy has proven to be an effective and minimally invasive treatment for abnormal uterine bleeding, infertility, and early pregnancy loss. Some of the most common uterine pathologic conditions treated by hysteroscopy are polyps and myomas. Even in patients without intrauterine pathology, endometrial ablation, first performed hysteroscopically, has decreased the need for hysterectomy in patients with abnormal uterine bleeding unresponsive to medical therapy.

This chapter describes the standard methods for diagnostic and operative hysteroscopy and then offers details of the hysteroscopic treatment of polyps and fibroids, both submucous and pedunculated intracavitary lesions. The chapter also describes techniques for endometrial ablation, including traditional hysteroscopic ablation and several innovative methods.

HISTORY

Hysteroscopy, first described in the late 1800s, did not find widespread clinical use for more than 100 years. In 1869, Pantaleoni performed the first diagnostic and therapeutic hysteroscopy when he used a modified cystoscope to look into the uterine cavity and cauterize a hemorrhagic growth.1 Early hysteroscopists used a tube to mechanically distend the uterus for visualization. Near the beginning of the 20th century, Dr. Isidor C. Rubin, a New York gynecologist best remembered for Rubin’s test, first used carbon dioxide (CO2) to distend the uterus for hysteroscopy. Around the same time, Professor C. J. Gauss, a German surgeon and descendant of the famous mathematician, first performed hysteroscopy using fluid distension media.2 However, hysteroscopy did not find widespread acceptance for another half-century.3

In the 1970s interest in hysteroscopy renewed, in parallel with the rapid advancement of diagnostic and operative laparoscopy. Probably the most important advances came in the form of improved methods for distending the uterine cavity, including use of viscous and low-density liquid solutions. Around the same time insufflation machines were designed for CO2 and fluid media that utilized high pressure and low flow, rather than the low pressure and high flow used for laparoscopy.46 Carbon dioxide was often used for diagnostic hysteroscopy, and fluid media became the standard for operative hysteroscopy. It was found that isotonic fluid was ideal for most operative procedures, whereas nonconductive hypotonic media was required for electrosurgical procedures.

The use of hysteroscopy became widespread in the 1980s with the development of better optics and lighting and the use of video cameras. Operative techniques for various intrauterine pathologic conditions continued to be developed. Most notably among these may be removal of submucous myomas using an enhanced urologic resectoscope,7 removal of uterine septum,8 and endometrial ablation using laser,9 resectoscopic loop,10 or rollerball.11 Today, hysteroscopy has become a standard diagnostic and therapeutic technique performed by most gynecologists.

INDICATIONS

BASIC HYSTEROSCOPIC EQUIPMENT AND TECHNIQUES

Distension Media

The uterine cavity is a virtual space, which must be distended with either gas or fluid media to visualize the endometrium and intrauterine pathology in three dimensions. In the past, contact hysteroscopy was performed without distension media for diagnostic evaluation of the endometrium based on color, architectural pattern, and contour. Today, diagnostic and operative hysteroscopy are most commonly performed with fluid distension media.

Dextran 70

One of the first fluid distension media used was high-viscosity dextran 70. A 32% solution of dextran 70 in 10% dextrose in water is a nonelectrolytic, nonconductive fluid with syrup-like consistency that can be used for both diagnostic and operative hysteroscopy. Because of its high viscosity, dextran 70 results in minimal leakage through the cervix and tubes. Because it is immiscible with blood, it allows for excellent visibility during surgical procedures. A syringe with manual pressure is most often used during hysteroscopy to slowly infuse dextran 70.

Dextran 70 is rarely used today as hysteroscopic distension media because of several associated problems.13 From an operational perspective, dextran 70 solutions cause instruments such as graspers and scissors to become permanently inoperable if the solution is allowed to dry on the instruments. This problem can usually be avoided by immediate cleaning shortly after finishing the procedure.

Fluid overload is one of the most common serious problems that can result from intravascular intravasation of dextran 70. Each 100mL of dextran 70 absorbed results in an increase in the intravascular volume of 800mL. For this reason, it is recommended to use no more than 500mL of the solution during an individual procedure.

Another risk of intravascular intravasation of dextran 70 is disseminated intravascular coagulopathy. The mechanism of this uncommon complication is suspected to be toxic effects of dextran 70 on pulmonary capillaries.

Finally, allergic reactions to dextran 70 have also been reported. The risk of anaphylaxis while using dextran 70 for hysteroscopy has been estimated to be as high as 1 per 1500 cases.14

Low-Viscosity Fluid

Low-viscosity fluids are the most common distension media used today because they are suitable for both diagnostic and operative hysteroscopy, are relatively inexpensive, and are relatively low risk. Isotonic electrolyte-containing fluids can be used for all operative procedures except those requiring traditional electrosurgery, although technologic advances have allowed its use even with these procedures. Hypotonic nonelectrolyte media is used for most electrosurgery (i.e., resectoscope) procedures.

Isotonic electrolyte-containing fluids are the most common distension media used for diagnostic hysteroscopy and operative procedures using mechanical instruments, laser, and more recently available bipolar energy. Two commonly used types are 0.9% sodium chloride and lactated Ringer’s solution.

Hypotonic nonelectrolyte-containing fluids are required when the unipolar resectoscope is used, and several types are available. The most common fluids used are 5% mannitol, 3% sorbitol, and 1.5% glycine. The theoretical advantage of 5% mannitol is that it is rapidly broken down by the liver into glycogen and is excreted through the kidney, with a half-life of 100 minutes.15

The advantage of low viscosity fluids over carbon dioxide and hyskon 70 is the ability to easily flush blood, mucus, bubbles, and tissue fragments out of the visual field and uterus. However, proponents of hyskon 70 point out that the miscibility of blood in low viscosity fluids can result in decreased visibility.

The major risk of all low-viscosity fluid media is potentially fatal fluid overload from intravascular absorption. Hypotonic nonelectrolyte media has the additional deadly risk of acute hyponatremia. Both fluids therefore require close monitoring of fluid used and fluid recovered at frequent intervals throughout the hysteroscopic case. Some institutions use a fluid management system (e.g., Dolphin II, CIRCON, British Columbia, Canada) for this purpose.

When a fluid deficit of 1,000mL of nonelectrolyte solution is identified, blood should be drawn to determine electrolyte levels, the procedure should be terminated, and consideration should be given to administering diuretics, with close monitoring of electrolytes. Injection of 3 to 4mL of dilute vasopressin (10 units in 50mL saline solution) into the cervix decreases both intraoperative bleeding and intravasation for at least 20 to 30 minutes.16

DIAGNOSTIC HYSTEROSCOPY

For the majority of the 20th century, the only method available for directly visualizing intrauterine pathology short of hysterectomy was the blind procedure of D&C. In the 1970s, dramatic improvements in optical systems, light sources, and distension media allowed the widespread use of hysteroscopy for accurate diagnosis (and often treatment) of intrauterine pathology.

In the 1980s, the development of hysteroscopes with smaller diameters (<4mm) allowed the use of the hysteroscope for diagnosis without the need for either cervical dilation or anaesthesia. As a result, office hysteroscopy has become a common procedure, which has been documented to have the advantages of patient acceptability, diagnostic accuracy, and cost- effectiveness.17 Hysteroscopy is particularly useful for identifying focal lesions, which are often missed with endometrial sampling.18

HYSTEROSCOPIC POLYPECTOMY

Endometrial polyps are benign growths found within the uterine cavity. They are often asymptomatic and can perhaps remain undetected for decades. In women without symptoms, polyps are often found coincidentally when pelvic ultrasonography is performed for unrelated problems such as pain or during the investigation for infertility.

Polyps are often symptomatic. However, in women with abnormal uterine bleeding, investigation may lead to their detection. Symptoms most often related to uterine polyps include abnormal bleeding, postcoital staining, chronic vaginal discharge, or dysmenorrhea. Polyp-related bleeding is often characterized by increased clotting, intermenstrual or premenstrual spotting, or heavier menstrual flow. There is good evidence that polyps can decrease fertility and that their removal will improve the chances of pregnancy.21

In addition to women with abnormal bleeding and infertility, other women at increased risk for endometrial polyps include women on tamoxifen therapy and women with endocervical polyps, a quarter of whom will also have endometrial polyps.

It is obvious that symptomatic endometrial polyps should be removed. However, it is also important to remove asymptomatic polyps, particularly in postmenopausal women.22 Although the vast majority are benign, endometrial cancer and hyperplasia will be found in approximately 2% of endometrial polyps and are associated with coexisting malignancies elsewhere in the endometrium. In one study of more than 1400 polyps, endometrial cancer was found in 27 polyps (1.8%).22 All but one of these women were postmenopausal, and 26% were asymptomatic.

HYSTEROSCOPIC MYOMECTOMY

Leiomyomas are the primary indication for more than 40% of the 650,000 hysterectomies performed annually in the United States.23 Submucosal myomas likely account for 10% to 20% of all myomas. Many of these can be removed by operative hysteroscopy. In addition to preserving fertility in many cases, a hysteroscopic approach is associated with a shorter recovery period, lower complication rate, and lower cost than hysterectomy.

For a successful surgical outcome, it is important to identify preoperatively the size, number, location, and depth of intramural extension of uterine myoma. Myoma size, number, and location are determinants of complete resectability, the number of surgical procedures necessary for complete resection, the duration of surgery, and the potential complications from fluid overload.24

Numerous studies have demonstrated that preoperative saline infusion sonohysterography gives more information than hysteroscopy in respect of myomas. Chapter 30 reviews the topic of ultrasonography and sonohysterography in detail.

Hysteroscopic Classification of Myomas

A classification system is important to most accurately determine the appropriate method for performing myomectomy and counseling the patient on risk and prognosis. The European Society of Hysteroscopy classification system is based on myoma location and the amount of myoma protruding or encroaching on the endometrial cavity.25 In this system, Type 0 myomas are pedunculated, with the myoma lying completely within the endometrial cavity (Fig. 42-1). Type I myomas are described as sessile, with less than 50% intramural extension (Fig. 42-2). Finally, Type II myomas are submucosal in location, with more than 50% intramural extension. These include transmural myomas, which extend from the submucosal to the serosal edge. When viewed hysteroscopically, Type II myomas appear as a “bulge” into the endometrial cavity. Multiple myomas such as those in Figure 42-3 are not placed within this classification. They should not accessed by hysteroscopy.

This system was originally designed to classify myomas exclusively on hysteroscopic appearance. However, this approach has significant limitations. During hysteroscopy, myomas can be compressed and recede into the myometrium as a result of the pressure of the distension media, thereby preventing full visualization of the myoma. For this reason, preoperative evaluation with ultrasonography is required to accurately determine how many myomas are present and how deeply the myomas penetrate the myometrium.

An ultrasonographic classification system has been developed for intramural myomas that corresponds in part to the hysteroscopic classification and in part to the hysterosalpingography data26 (Table 42-1).

Table 42-1 Hysteroscopic and Sonohysterographic Classification System for Myomas Encroaching Upon the Endometrial Cavity

Hysteroscopic Type25 Sonohysterographic Class26 Description
Type 0 Class 1 Pedunculated myomas, where 100% of the myoma lies within the endometrial cavity with no intramural extension
Type I Class 2 Sessile myomas, with <50% intramural extension
Type II Class 3 Submucous myomas, with >50% intramural extension

Surgical Approach According to Stage

Buy Membership for Surgery Category to continue reading. Learn more here