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

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

Linda D. Bradley

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.⁴^–⁶ 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

Diagnostic Hysteroscopy

The most common indications for evaluation of the uterine cavity are abnormal uterine bleeding and infertility. Although hysterosalpingography (HSG) and modern ultrasonography are relatively sensitive in detecting intrauterine anomalies, diagnostic hysteroscopy remains the most accurate method available to visualize the cervical canal and uterine cavity. Today, there remain two schools of thought regarding initial evaluation of the uterine cavity. Although many clinicians utilize HSG, transvaginal ultrasonography, and sonohysterography to diagnose intrauterine abnormalities, many gynecologists continue to utilize diagnostic hysteroscopy in the office setting for this purpose. In addition, most gynecologists combine hysteroscopy with every dilation and curettage (D&C) procedure to exclude previously undetected focal pathology and to verify that previously diagnosed polyps have been completely removed during the procedure.

Operative Hysteroscopy

The two most common indications for operative hysteroscopy are (1) directed biopsy of focal lesions and (2) treatment of intrauterine lesions, including endometrial polyps and intracavitary leiomyomas, uterine septa, and cornual tubal occlusion. Removal of uterine septum and treatment of cornual occlusion with cannulation are covered in Chapters 43 and 47.

Less common indications for operative hysteroscopy include retrieval of a “lost” intrauterine device with a retracted tailstring, discussed in Chapter 27. Hysteroscopy has also been used in early pregnancy for chorionic villus sampling. The newest indication is the placement of coils into the intramural section of the tube for permanent sterilization, which is covered in Chapter 28.

In the recent past, hysteroscopy was commonly used to perform endometrial ablation. Recently, automated ablation techniques that are not performed hysteroscopically have become more common.

BASIC HYSTEROSCOPIC EQUIPMENT AND TECHNIQUES

Types of Hysteroscopes

All hysteroscopes incorporate an optical system (including an eyepiece and objective lens) and a light source within a single barrel up to 4mm in diameter. The most commonly used rigid hysteroscope has an objective lens at the tip offset by 12 to 30 degrees from the horizontal plane, although a “0 degree hysteroscope” is also used and other lens angles are available.

Ridged Hysteroscope

A ridged hysteroscope is used with a sleeve, which allows for the input of distension media. A diagnostic sleeve has a diameter of up to 4.5mm and usually has only a media input channel. An operative sleeve has a diameter of 8 to 9mm and has three channels: an input and outflow channel for media and a 2-mm operating channel for the use of semirigid instruments. These include scissors, biopsy forceps, and graspers that can be used for a full range of hysteroscopic tasks. Laser fibers and coaxial bipolar electrodes have also been used through the operative channel.

A resectoscope, similar to a urologic resectoscope, has a 9-mm diameter sleeve with a built-in mechanism to extend and retract a monopolar electrosurgical device using a thumb lever. The monopolar device can be a 5- to 7-mm cutting loop for removal of polyps, septum, or leiomyoma, or a rollerball or barrel used for endometrial ablation.

Flexible Hysteroscope

A flexible hysteroscope resembles a short colonoscope with variable sizes ranging from 3.1 mm to 5.0 mm. The larger scope has an instrument port with a diameter of 1.8mm for the use of very delicate flexible instruments. The hysteroscope tip can be deflected up to 160 degrees using a thumb control near the eyepiece. It is often used in an office setting because of its small diameter (and thus no need for cervical dilation). In addition to diagnostic hysteroscopy, it can be used for fine procedures such as directed endometrial biopsy, chorionic villus sampling, tubal canalization, and removal of a “lost” intrauterine device.

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.

Carbon Dioxide

Carbon dioxide was commonly employed for diagnostic hysteroscopy because it allows for excellent clarity in the absence of bleeding. Compared to fluid media, it allows a wider field of view at lower magnification and is not messy. However, when bleeding occurs it is difficult to clear the lens, resulting in limited visualization.

Carbon dioxide is less commonly used today than in the past for several reasons. A major cost disadvantage is that CO₂ requires the expense of a specially designed hysteroscopic insufflator that produces higher pressures (up to 100 mm Hg) at relatively low flow rates (40 to 60mL/min). This is in contrast to laparoscopic insufflators, which are designed to deliver relatively lower pressures (<25 mm Hg) at high flow rates (up to 6L/min).

Another problem associated with the use of CO₂ for hysteroscopy is the rare occurrence of fatal gas embolism. Although a small amount of CO₂ is rapidly absorbed and cleared from the body via respiration, an open vessel in the uterus can allow enough gas into the venous system to result in fatal heart block.¹² To minimize this risk when CO₂ is used for hysteroscopy, it has been recommended that the Trendelenburg position should be avoided, the cervix should not be dilated, and no operative procedures should be performed.

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

Analgesia and Anesthesia

Narrow rigid and flexible hysteroscopes with diameters less than 4mm can often be inserted into the uterus without dilating the cervix. For this reason, they are often used in an office setting using only oral analgesics or with the addition of a paracervical block.

For operative procedures, larger hysteroscopes and resectoscopes are used that require cervical dilation before insertion and are therefore used primarily in an operating room under general or regional anesthesia.

Power Sources

The first, and perhaps most versatile, hysteroscopic power source is unipolar electrosurgery. A resectoscope with a thin loop electrode is used to resect leiomyomas or divide a septum. This approach is ideal for resecting dense tissue and maintaining hemostasis. Because this is a monopolar device, it must be used with nonconducting hypotonic distension media. Bipolar and insulated monopolar systems have been developed, with the advantage of working with the safer isotonic distension media. These methods are more expensive because they are based on disposable technology.

Several lasers have been developed for endometrial ablation, including the potassium-titanyl-phosphate (KTP), argon, and neodymium:yttrium-aluminum-garnet (Nd:YAG) lasers. Each has relative advantages and disadvantages and tends to be more technically challenging and expensive than electrosurgerical techniques.

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

Office Hysteroscopy

Office hysteroscopy is comfortable, quick, and associated with low complication rates. The cervix can be made more pliable by the use of oral or vaginal misoprostol to make the procedure more tolerable, especially in women at risk for cervical stenosis. Oral analgesics, such as ibuprofen, are also helpful.

A low (<1%) complication rate is noted when office hysteroscopy is performed by skilled physicians. Complications include uterine perforation, infections, excessive bleeding, and complications related to the distension media.¹⁹

Common Pathology

The list of lesions that can be visualized hysteroscopically is long and includes endometrial polyps, submucosal and intramural myomas, synechiae, retained products of conception, foreign bodies, endocervical lesions, endometrial atrophy, endometrial hyperplasia, endometrial cancer, arteriovenous malformations, gestational trophoblastic disease, cesarean scar defects, incomplete abortion, and pregnancy. In some cases, endometrial gland openings associated with adenomyosis can be observed. Theoretically, the specificity and positive predictive value of hysteroscopy in cases of abnormal uterine bleeding should be 100%. In practice, however, the false-negative rate is 2% to 4% and is the result of operator error in detecting abnormal endometrial lesions.

Technique

A slow and thorough evaluation is important to identify abnormalities of the endocervix, fundus, and tubal ostia. Myomas of the endocervix and lower uterine segment can easily be missed with too rapid insertion of the hysteroscope. Likewise, if the hysteroscope is too quickly placed above an intracavitary lesion, it can likewise be missed.

Lesion Size

The size of lesions cannot be accurately determined hysteroscopically, in contrast to transvaginal ultrasound. This is because the hysteroscopic eyepiece is focused at infinity, thereby making the objects that are closer appear magnified and objects viewed further away smaller.²⁰ This phenomenon can lead to surprises in the operating room, especially when the size of a lesion, particularly submucosal myomas, may be underestimated.

Disappearing Phenomena

False-negative views can occur during hysteroscopy when using CO₂ because of the high intrauterine pressures. The disappearing phenomena refers to the flattening of endometrial polyps, resulting in a negative hysteroscopic view. This can be avoided by decreasing the intrauterine pressure at the end of the procedure and reinspecting the endometrial cavity.

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.

Figure 42-1 Hysteroscopic view of a type 0 myoma. It is pedunculated and the total myoma lies within 100% of the endometrial cavity.

Figure 42-2 Hysteroscopic view of a type I myoma that involves less than 50% of the myometrium.

Figure 42-3 Extirpated uterus showing a large (6 cm) intracavitary myoma with multiple intramural and submucous myomas.

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 data ²⁶ (Table 42-1).

• Class 1 myomas are intracavitary and do not involve the myometrium. The base or stalk is visible on saline infusion sonohysterography (Fig. 42-4).

• Class 2 myomas have a submucosal component that involves less than 50% of the myometrium (Fig. 42-5).

• Class 3 myomas have an intramural component greater than 50%. They can be transmural and located anywhere from the submucosal to the serosa. These myomas often appear as a bulge or indentation into the submucosal when viewed hysteroscopically (Fig. 42-6).

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

Figure 42-4 Class 1 myomas are intracavitary and do not involve the myometrium. The base or stalk is visible with saline infusion sonohysterography.

Figure 42-5 Class 2 myomas have a submucosal component that involves less than 50% of the myometrium.

Figure 42-6 Class 3 myomas have an intramural component greater than 50%.

Surgical Approach According to Stage

The degree of surgical difficulty and thus the risk to the patient is related to the depth of penetration and size of the myomas. Pedunculated hysteroscopic Type 0 or sonohysterographic Class 1 myomas up to 3cm in dimeter can usually be easily removed hysteroscopically. Larger hysteroscopic Type 0 myomas (>3cm) and hysteroscopic Type I (Class 2 on sonohysterography) myomas can be approached hysteroscopically. However, the risk of fluid intravasation increases as a result of increased surgical time and the opening of myometrial venous channels during resection. Operative hysteroscopy is made more difficult by limited space within the uterus and poor visibility due to an inability to further distend the uterine media and the large amount of myoma “chips” that accumulate within the endometrial cavity. Often, incomplete removal of larger myomas requires two or more separate operative procedures. Only the most experienced hysteroscopist would attempt a hysteroscopic resection of an intracavitary myoma 5cm or larger. Myomas that are large and multiple (see Fig. 42-3) should not be excised by hysteroscopy.

Hysteroscopic resection of hysteroscopic Type II (or sonohysterography Class 3) myomas should only be approached by the most skilled hysteroscopist and are more commonly approached abdominally by laparoscopy or laparotomy. Hysteroscopic removal of Type II myomas is associated with a greater risk of fluid intravasation and uterine perforation and commonly requires two or more procedures for complete removal. Hysteroscopic resection of Type II myomas results in extensive damage to the endometrium, resulting in an increased risk of Asherman’s syndrome as well as decreased fertility and hypomenorrhea. In an attempt to minimize intrauterine adhesions, patients are often treated postoperatively with estrogen and progestin, intrauterine stents, or “second look” hysteroscopy. However, the efficacy of these approaches has not been studied. Because of this risk, hysteroscopic removal of Type II myomas generally should not be used in women who desire future fertility.

Patient Selection

The ideal patient for hysteroscopic myomectomy should meet the following criteria:

• single intracavitary myoma or one involving less than 50% of the myometrium and up to 3 cm in diameter.

• uterine size less than 12 to 14 weeks

• normal hemoglobin and normal electrolytes.

Experienced hysteroscopists can remove multiple intracavitary myomas in women who desire future pregnancy. These patients benefit from a two-stage operative hysteroscopic myomectomy, in which myomas are removed from only one uterine wall at a time. This aim is to decrease the risk of apposition of the uterine walls and the development of postoperative intrauterine synechiae.

Preoperative Medications

Cervical Preparation

Use of a laminaria or misoprostol is recommended to facilitate dilation. Additionally cervical softening agents decrease the risk of cervical tears, decrease the risk of uterine perforation, and decrease the use of unnecessary force to achieve cervical dilation. The most common complications associated with operative hysteroscopic surgery is cervical laceration (Table 42-2).

Table 42-2 Risk of Complications Associated with Endometrial Ablation and Resection ^13,¹⁴

Complication	Rate
Intraoperative
Cervical lacerations	4%
Uterine perforation	1.4%
Bowel/bladder/vessel injury	Rare
Fluid overload	Rare
Postoperative
Infection	0.4%
Hematometra	1–2%
Delayed
Bleeding requiring further surgery	10%
Subsequent endometrial cancer	Rare

Laminaria can be inserted into the cervix 12 to 24 hours before surgery. This will facilitate cervical dilation, but requires an extra office visit and cannot be used in women with shellfish or iodine allergy.

Misoprostol can be administered vaginally or orally to soften the cervix, although this indication is not approved by the Food and Drug Administration (FDA). Vaginal misoprostol (200 to 400μg) given 8 to 12 hours before surgery reduces the need for cervical dilation, decreases cervical complications, and reduces operative time in comparison with controls.²⁷ Alternatively, oral misoprostol (400μg) can be given 12 and 24 hours before surgery to soften the cervix and make dilation easier.²⁸ Side effects associated with misoprostol include lower abdominal pain and small amounts of vaginal bleeding.

Prophylactic Antibiotics

Most surgeons do not routinely administer preoperative prophylactic antibiotics before myomectomy. However, prophylactic antibiotics should be administered to high-risk patients, such as women with a history of pelvic inflammatory disease, prior history of tubo-ovarian abscess, or documented hydrosalpinges. Antibiotics are also indicated for patients with history of artificial joints, hip replacement, or with mitral valve prolapse with regurgitation. Many surgeons will give prophylactic antibiotics if a procedure is anticipated to last more than 30 minutes or incomplete removal of a myoma is planned or found to be necessary intraoperatively.

Technique of Hysteroscopic Myomectomy

Techniques for removing pedunculated and submucosal myomas include avulsion, scissors, wire-loop resection with bipolar or monopolar equipment, vaporization, morcellation, and laser vaporization. In many cases, a combination of several techniques is required to facilitate complete removal. Initial techniques utilized large intrauterine graspers such as Corson graspers that avulsed myomas; however, without utilizing a hysteroscope, complete removal cannot be accurately determined.

In 1978, Neuwirth first reported the use of the monopolar urologic resectoscope for resection of submucosal myomas.²⁹ Hysteroscopic wire-loop resection still remains the most popular method of removing myomas, but newer techniques are emerging.

The development of the continuous flow resectoscope permitted distension of the uterine cavity with fluid and removal of blood and debris. Further improvements in optics, video recording, bipolar technology, and uterine distension systems provided additional safety features for operative hysteroscopic procedures.

Performing operative hysteroscopic myomectomy requires four essential components:

• thorough preoperative evaluation of uterine myomas, including a detailed knowledge of the number, size, location, and depth of myoma penetration into the myometrium

• adequate eye-hand coordination

• understanding of fluid management

• knowledge and judgment as to when to discontinue the hysteroscopic approach.

Special Techniques

Fertility Preservation

If the patient desires fertility, overzealous resection of the myometrium must be avoided. Asherman’s syndrome may occur when large portions of overlying endometrial tissue are resected with a sessile myoma. Patients who desire fertility and have multiple intracavitary myomas, especially those with myomas on opposite walls, may require resection on two separate occasions to minimize chances of intrauterine synechiae developing postoperatively.

For women wishing to maintain or preserve fertility who undergo large myoma resection or have resection of “kissing lesions,” many gynecologists will empirically administer high-dose estrogen in an effort to re-epithelize the endometrium and decrease the risk of intrauterine adhesions. A typical regimen is conjugated estrogen 0.625 to 1.25mg twice daily or estradiol 2mg twice daily for 25 days, followed by 12 days of medroxyprogesterone 10mg.

Another approach is to place a postoperative intrauterine stent. Either a pediatric catheter inflated with 15 to 20 cc or a balloon uterine stent specifically designed for this purpose may be inserted for 7 to 10 days to prevent the juxtaposition of the uterine walls.

A final approach is to perform office hysteroscopy within the first 7 to 14 days after extensive myomectomy to evaluate the endometrium for synechiae. If detected early, the adhesions are filmy and easily lysed with the distal tip of the hysteroscope. In some circumstances hysteroscopic visualization every 7 to 10 days may be required until regeneration of the endometrium is confirmed and filmy adhesions treated. When performed too late, dense fibrous adhesions may be encountered, requiring operative hysteroscopic adhesiolysis.

Large Myomas

Larger myomas (>3cm) may benefit from being “debulked” initially by using a bulk vaporization electrode (VaporTrode, ACMI, Southborough, Mass.) or by being divided into four quadrants and retrieved with Corson graspers. Vaporization electrodes are grooved or spiked barrel shape, with a number of edges that function like an array of narrow caliber electrodes, each with the ability to vaporize adjacent tissue. Large volumes of tissue are rapidly desiccated and vaporized, eliminating accumulation of tissue fragments.

To achieve this result, the power requirements are several times higher. For example, with a Valleylab Force F/X electrode, settings of 200 to 220 watts are necessary. This technique should be avoided at the cornua and isthmus regions to reduce the electrosurgical risk of perforation.

Many surgeons use a technique of dividing larger circular myoma into four sections using a straight wire loop. Once the myoma is divided into four pieces, each piece can be avulsed and removed through the dilated cervix.

Prostaglandin F_2α Analogue

Despite evaluation, some myomas are technically challenging to remove or the surrounding pseudocapsule is not well demarcated. Myomas with a significant intramural location require the most experienced hysteroscopic expertise to remove. In recent studies carboprost, a methyl analogue of prostaglandin F_2α, showed promise in facilitating enucleation of myomas. This is not an FDA-approved use of the drug. A recent report describes the successful use of carboprost in 10 women to facilitate hysteroscopic myomectomy.³² Carboprost led to contraction of the myometrium and extrusion of the unresectable intramural component into the endometrium, facilitating hysteroscopic resection.

Side effects include transient fever, nausea, diarrhea, and vomiting. Additionally, due to strong uterine contractions, visualization was hampered and required increased intrauterine pressures to distend the endometrial cavity and manipulate the resectoscope in some cases.

Intraoperative Ultrasonography

Intraoperative ultrasonography guidance during operative hysteroscopy is useful for resection of myomas or septa that are hard to define. Ultrasound guidance may allow resection beyond the limit conventionally defined by hysteroscopy.

Bipolar Technology

Bipolar technology enables surgeons to diagnose and treat various benign intrauterine conditions, including myomas and polyps, using electrolyte-containing distension media (i.e., saline solution). Several innovative electrode designs, including ball, twizzle, and spring configurations, deliver bipolar energy through #5 French instrument channels to vaporize, cut, and desiccate tissue. Similar surgical strategies and caveats as discussed for monopolar technology apply when the bipolar technique is used.

Postoperative Management

Most patients experience minimal postoperative pain after hysteroscopic myomectomy. Mild cramping will usually respond to nonsteroidal anti-inflammatory drugs (NSAIDs), and few patients will require opiods. Typically patients resume normal activities within 48 hours after surgery. Bathing is permissible immediately after myomectomy and sexual activity can be resumed 1 week postoperatively.

Most patients will have a serosanguineous discharge lasting for 1 to 4 weeks after hysteroscopic myomectomy. If an incomplete resection has occurred, some patients may pass pieces of myomas several weeks after the procedure and have prolonged discharge. Patients should be warned of the risk of infection and return for signs of this complication.

ENDOMETRIAL ABLATION

Endometrial ablation was developed as a minor surgical procedure to treat women with intractable heavy menses unresponsive to medical management who no longer desire fertility. Each year approximately 200,000 women undergo an endometrial ablation. Compared to hysterectomy, endometrial ablation offers the advantages of avoiding the morbidity and prolonged recovery associated with major surgery and allows conservation of the uterus.

In the past decade, methods for endometrial ablation have been developed that do not require hysteroscopy. In patients with relatively normal uteri, these nonhysteroscopic techniques have been found to be just as effective as hysteroscopic techniques, and appear to be safer and less technically demanding. Both traditional hysteroscopic and contemporary nonhysteroscopic methods for endometrial ablation are described here.

Preoperative Evaluation

A thorough preoperative evaluation is imperative because many serious diseases can present as abnormal uterine bleeding. The investigation and management of abnormal uterine bleeding is described in Chapter 21. A brief overview is given here to highlight the importance of a proper evaluation before a surgical procedure.

The evaluation begins with a detailed history, physical examination, and ultrasonographic imaging. Important laboratory tests for evaluation of women with menorrhagia include a pregnancy test, thyrotropin level, and complete blood count with platelet count. Many clinicians recommend a platelet function screen or a von Willebrand ristocetin cofactor. If the platelet function screen is abnormal, testing for von Willebrand’s disease is indicated. A recent study reported 47% of reproductive-age women with menstrual dysfunction were found to have a hemostatic abnormality such as platelet dysfunction, von Willebrand’s disease, or coagulation factor deficiencies.³³

Endometrial Biopsy

Women over age 40 should have an endometrial biopsy to exclude hyperplasia or malignancy. Endometrial biopsy should also be performed in women under age 40 with risk factors for endometrial hyperplasia and cancer, such as diabetes, prolonged steroid use, obesity, protracted history of irregular cycles, unopposed estrogen therapy, or polycystic ovary syndrome. Women who have endometrial hyperplasia with or without atypia should not be offered endometrial ablation.

Risks

Complications of endometrial ablation are uncommon, and many are even less common with the newer ablative techniques compared to hysteroscopic techniques. The interoperative risks include fluid overload, uterine perforation, cervical lacerations, and bowel injury (see Table 42-2). These complications are more common in women undergoing traditional hysteroscopic ablation and resection techniques.

Postoperative complications include hematometra and infection. Prophylactic antibiotics are often used, but have not been shown to decrease the infection risk.

Delayed complications include continued bleeding heavy enough to require repeat ablation or hysterectomy. A concern in the early years of ablation was that the procedure might decrease the ability to make an early diagnosis of cancer of the endometrium by masking early bleeding. Although endometrial cancer has been reported after ablation, delayed diagnosis has yet to be documented. If a woman who has had an endometrial ablation later requires hormone replacement therapy, progesterone therapy is required because the remaining viable endometrium puts the patient at risk for hyperplasia or malignancy if unopposed estrogen is used.

Continued menstruation after ablation is not considered to be a complication. The reported amenorrhea rate is as high as 40% after hysteroscopic ablation and nonhysteroscopic methods. Endometrial ablation should only be offered to women who are willing to accept eumenorrhea, hypomenorrhea, or cyclic bleeding rather than amenorrhea as a final clinical result.

Endometrial Ablation Techniques

Currently there are eight different methods to perform endometrial ablation. The three first-generation hysteroscopic techniques include electrosurgical endomyometrial resection, electrosurgical rollerball ablation, and laser ablation.

Second-generation techniques, also referred to as global methods, were developed that do not use hysteroscopy to perform the ablation. Hysteroscopy is an integral part of only one of these systems (i.e., Hydro ThermAblator). However, many clinicians perform diagnostic hysteroscopy before using any of the global methods.

First-Generation Hysteroscopic Endometrial Ablation

In the early 1980s, endometrial ablation was established as an alternative to hysterectomy for treatment of menstrual dysfunction in women with intractable menorrhagia. Mimicking the physiologic effect of Asherman’s syndrome, the ultimate goals of endometrial ablation were to create severe endometrial scarification and secondary amenorrhea. Initially, Goldrath and colleagues reported laser endometrial ablation using the Nd:YAG laser fiber through the operating port of a hysteroscope. However, this method waned in popularity due to costs and riks of complications in less experienced hands.⁹

Endomyometrial resection utilizing a resectoscope was first reported by DeCherney and Polan in 1983.³⁴ This technique utilizes unipolar electrocautery and is performed with hypotonic nonelectrolyte-containing distension media. This technique was the forerunner of hysteroscopic rollerball endometrial ablation, which has become the “gold standard” to which all emerging endometrial ablation technology is compared. This technique, which also uses a resectoscope, was popularized by Vancaillie in 1989.¹¹ Each of these devices destroys the basalis layer of the endometrium and is designed to result in hypomenorrhea or amenorrhea.

Review of the first decade of hysteroscopic ablation revealed relatively good results as well as moderate difficulties. Cumbersome equipment, patient safety, need for highly trained operating room staff, hampered visibility, and both intraoperative and postoperative complications hindered widespread application of hysteroscopic endometrial ablation.

Second-Generation Endometrial Ablation Devices

Second-generation, or global, endometrial ablation refers to destruction of the endometrium with devices placed blindly into the endometrial cavity and usually activated without hysteroscopic guidance. Little or no hysteroscopic skills are required when performing endometrial ablation with second-generation devices. Currently, FDA-approved devices available in the United States considered to be second-generation procedures include systems that use a uterine balloon, hot saline irrigation, cryosurgery, radiofrequency, and microwave.

Second-generation technology offers the advantage of shorter procedure times while retaining the acceptable outcome rates, similar to those of traditional rollerball ablation. However, these second-generation devices have limited or no ability to treat intracavitary pathology. Only two second-generation ablation devices currently permit treatment of polyps alone (NovaSure) or polyps plus myomas (Microwave Endometrial Ablation System). For this reason, it is important for clinicians who routinely use these ablation devices to be skilled in operative hysteroscopy so that intracavitary pathology can be concurrently treated when necessary.

Endometrial Preparation before Ablation

The goal of endometrial ablation is destruction of the basalis layer of the endometrium. Under hormonal control, the endometrium varies greatly in thickness throughout the menstrual cycle. The endometrium is thinnest (<4mm) during menses, gradually increases in the proliferative phase (4–10mm), and is thickest during the secretory phase (10–15mm). The amount of stromal edema and debris also increases during the secretory phase and menstruation.

Ideally, the patient should be scheduled during the early proliferative phase. Otherwise, hormonal suppression of the endometrium is required to thin endometrium and increase the chances of success of the ablation. Hormonal suppression also appears to improve visualization, reduce operative time, decrease the risk of fluid overload, and increase amenorrhea and hypomenorrhea rates. However, no studies have proven that hormonal suppression improves long-term outcomes.

Hormonal options for endometrial suppression include the use of depot leuprolide acetate, danacrine, oral contraceptive pills, and progesterone-only pills 4–8 weeks before surgery. Surgical preparation with suction or sharp curettage immediatedly before ablation has also been used with reported success.

Technique of Hysteroscopic Rollerball Endometrial Ablation

The general concept of hysteroscopic endometrial ablation involves thorough destruction of the basalis layer, cornua, and lower uterine segment. Currently there are three methods available to perform hysteroscopic endometrial ablation: rollerball desiccation, endomyometrial resection and desiccation, and laser endometrial desiccation, although the latter technique is rarely used today. For this reason, only the first two techniques are reviewed here.

Vasopressin

Vasopressin is used to decrease the risk of fluid absorption, fluid overload, and intraoperative bleeding. A dilute solution of vasopressin (10 units in 50mL saline solution) is injected as 5-mL aliquots into the stroma of the cervix at 12, 3, 6, and 9 o’clock position. This causes intense arterial and myometrial wall contractions for 20 to 45 minutes Vasopressin is not approved by the FDA for this purpose and should not be used in patients with hypertension.

Supplementary Treatments

Uterine cramping is common after endometrial ablation. To decrease postoperative cramping, a paracervical block (0.25% bupivacaine without epinephrine) can be placed and the patient can be given intravenous NSAIDs (ketorolac tromethamine 30 to 60mg). An antiemetic given during surgery is recommended to decrease postoperative nausea.

Rollerball Electrode

The depth that the endometrium is coagulated depends on tissue and equipment factors. Tissue-related factors include endometrial thickness and variations in tissue impedance related to the number of previous passes. Equipment-related factors include the diameter and shape of the electrode, waveform and power utilized, cleanliness of the electrode, time of exposure of the electrode to the endometrium, pressure against tissue, and speed of electrode. Several varieties and shapes of electrodes are available to perform hysteroscopic endometrial ablation, including ball, barrel, ellipsoid, and large caliber loops.

Most surgeons perform roller-ball endometrial desiccation with a 3-mm roller-ball probe, with the goal of systematically destroying the entire endometrium to the lower uterine segment and cornual region. Endometrial ablation is performed under direct and constant view of the endometrium with a distension medium that is compatible with the electrical energy used. Monopolar electrosurgical equipment requires the use of nonelectrolyte-containing distension media, such as glycine, sorbitol, or mannitol. Bipolar equipment will only function in the presence of electrolyte-containing media such as saline solution.

Electrical Settings

Monopolar ablation is performed at 60 to 100 watts of pure cutting current. Although some surgeons prefer coagulating current, others believe that the interrupted nature of this type of current may cause an uneven amount of protein bonding, theoretically reducing the homogeneity of the tissue effect. Early coagulation of the superficial layers of the tissue can result in increased impedance, further reducing transmission of current to deeper layers.

Systematic Plan of Ablation

Following a systematic surgical plan ensures optimal clinical outcomes. Excellent visualization of the entire uterine cavity and endocervix is imperative. All intrauterine landmarks are clearly delineated hysteroscopically before initiating the procedure. Once a panoramic view of the endometrium is accomplished, the surgeon should determine if there is any previously unrecognized pathology. If a subtle lesion is discovered, then a directed biopsy with a wire-loop electrode is performed and the specimen labeled and submitted separately.

Once the surgeon visualizes all of the landmarks, the lower uterine segment is cauterized circumferentially to mark the endpoint and lowest level of endometrial ablation therapy. Ablation of the endocervix is avoided to minimize the risk of cervical stenosis. Cervical stenosis can result in cyclic pain, dysmenorrhea and, in severe cases, hematometra.

After the lower uterine segment is identified and coagulated circumferentially, the cornua and fundal region are treated initially. The roller-ball is advanced to the fundus and then directed at the cornua utilizing a “touch technique” to desiccate the cornua. It must be remembered that the thinnest region of the uterus is at the cornua and cesarian section scars. Extra care must be taken to avoid forward pressure, which could cause perforation. The most challenging part is the fundus because the roller-ball cannot truly be rolled against the fundus.

Next the posterior wall, followed by the lateral walls and anterior walls, is treated. Traditional technique utilizes direct tissue contact, such that one half of the roller-ball is buried in the endomyometrial juncture. Always activate the foot pedal when the electrode is moving toward the surgeon. To avoid the risk of perforation, the surgeon should avoid any forward movement of an activated electrode to decrease the risk of burns to the pelvic viscera. Intermittently, the roller-ball may need to be cleaned and debris evacuated to provide optimal visualization.

At the conclusion of the endometrial ablation procedure, the intrauterine pressure is reduced to identify small bleeders, which may be treated with coagulation current.

Technique of Endomyometrial Resection

The technique of endomyometrial resection was pioneered by DeCherney and colleagues.¹⁰ The 90-degree wire loop, generally 3 to 4mm deep, is buried into the endometrium, and using 60 to 80 watts of pure cutting current, is advanced under direct view to the lower uterine segment. The endomyometrial junction is shaved off, creating crescent-shaped tissue fragments.