1.1 Introduction

Hysteroscopy has become a mainstay within a gynecologic surgeon’s practice for endoscopic examination of the uterine cavity due to the benefits of its relatively low-risk methods and accurate diagnostic capabilities. The hysteroscopic approach provides excellent visualization and is minimally invasive in that no incisions are required for therapeutic procedures. New tools are constantly being developed for the office as well as for the operating room, broadening the options available to address a wide variety of intrauterine pathologies.

1.2 Hysteroscopes

The first hysteroscopes that were developed in the late nineteenth century were rigid-rod lens systems. This is still the most commonly used design, but flexible fiber-optic hysteroscopes and digital hysteroscopes are currently available. The flexible hysteroscopes are 3.2–3.5 mm in diameter with a tip that deflects over a range from 90º to 120°, and have the advantage of not requiring preliminary dilation of the cervix or use of anesthesia. They are most commonly used for office hysteroscopy. The disadvantage is that because they are single-channel scopes with 1 mm working channels having a noncontinuous flow, they can only be used for diagnostic purposes and they are more costly, less durable, and cannot be sterilized within an autoclave as is the standard for most rigid hysteroscopes. Digital hysteroscopes such as the Endosee^© have recently become available for diagnostic use; they are cordless and utilize single-use cannulas.

Rigid hysteroscopes come with several options for viewing angles: 0°, 12°, 15°, 25°, or 30°. The 12° viewing angle is helpful for surgical procedures because it keeps the working instruments in the field of view at all times. On the other hand, the 30° viewing angle is advantageous because only small rotational movements are needed to visualize the entire cavity, thereby causing less discomfort to the patient. Typically, the single-flow sheath of the rigid hysteroscope has a 2.9 mm diameter and is used in combination with an outer sheath whose diameter ranges from 3.2 to 5.3 mm, creating a continuous flow system as well as permitting the passage of semi-rigid operating instruments such as scissors, graspers, or biopsy forceps. Small 5 French bipolar electrodes can be passed through the working channels of the continuous flow hysteroscopes and can be used for resection of small myomas, polyps, scar tissue, and septa.

For the purpose of definition, a resectoscope is a hysteroscope operating with radiofrequency or mechanical energy and ranging in diameter from 21 to 28 French. The working instruments employed with the resectoscope include loop electrodes, roller balls, and barrels as well as vaporizing electrodes. Resectoscopes may employ monopolar radiofrequency energy where the current flows from the active electrode (i.e., the loop) through the tissue via random diffusion to a remotely located large dispersive electrode. Electrodes in a ball or barrel have a larger surface area than cutting loops and serve well for tissue desiccation and are used to perform endometrial ablations. Monopolar electrodes necessitate the use of nonconductive fluid distention media such as glycine, sorbitol, or mannitol (see “Distending Media” section later in the chapter). Bipolar resectoscopes allow the current to arc only through the tissue, which comes into direct contact with the loop and its return electrode, and require a conductive electrolyte-containing distention medium to be used.

1.3 Morcellators

Hysteroscopic morcellators became available in the United States in 2005 as an option for mechanical resection of intracavitary lesions in which thermal energy is not utilized, and may be used with isotonic electrolyte-rich distention media such as normal saline. The reciprocating blades of the instrument cut while the suction element removes the tissue. Consequently, a morcellator cannot cauterize blood vessels. Due to their side-opening cutting design, the morcellators have limited utility in cases with myomas that have deep involvement into the myometrium. The clear advantage of morcellators is the ease in attaining visibility due to the continuous suction and collection of the resected tissue into a specimen bag [1]. Classic loop resectoscopic surgery can be challenging secondary to the aggregation of tissue chips, formation of gas bubbles, and blood clots obstructing visualization. The time involved in removing chips can be cumbersome when taking into account the multiple removals and reinsertions of the resectoscopic device into the cavity. When using a morcellating device, on the other hand, clearing the cavity can be achieved by activating the device and allowing the suction element to remove the visual field of the debris.

1.4 Distention Media

The options for distending medium include both fluid and gaseous media. Carbon dioxide (CO₂) is the only gaseous media used because it is highly soluble in blood, and currently is only an option for diagnostic procedures because the field of view is obscured when the gas encounters blood. CO₂ gas is readily soluble in the blood stream and can lead to serious risk of gas embolism, and if the volume of the gas embolism is large, it can result in catastrophic cardiovascular collapse and death.

Low-viscosity fluid is the distention media of choice for current hysteroscopic technologies. High-viscosity media such as Dextran-70 (Hyskon) has fallen out of favor secondary to the low maximum infusion volume of 300 mL, as higher volumes can be associated with adverse outcomes such as pulmonary edema and right-sided heart failure secondary to its impact on expanding the patient’s plasma volume. Furthermore, there are concerns of anaphylaxis as well as strict regimens for cleaning instruments when used in high-viscosity fluids, which have further limited the practical use of this media.

The available low-viscosity media vary in electrolyte content as well as in osmolality. The common electrolyte-free media include 1.5% glycine, 5% mannitol, and 3% sorbitol. The electrolyte-free fluids have unique features that vary in their osmolality and have different pathways of metabolism with resultant breakdown by-products. Plasma absorption of electrolyte-free media can lead to hyponatremia and other electrolyte disturbances. The signs of their systemic absorption included nausea, vomiting, and cardiac arrhythmias as well as a range of neurological symptoms such as cerebral edema, seizures, tremors, and even coma or death. On the other hand, 5% mannitol is near isotonic to plasma. However, because it lacks electrolytes, excess absorption can still cause hyponatremia with all the risks noted earlier. As a general rule, the serum sodium will be reduced by 10 mEq/L for every 1 L of electrolyte-free media absorbed. Subsequently, the American Association of Gynecologic Laparoscopists (AAGL) guidelines recommend concluding the procedure that employs hypotonic solutions when the fluid deficit reaches 1,000 mL [2].

On the other hand, electrolyte-rich solutions such as normal saline are isotonic, and thus are safer when they are systemically absorbed as they do not cause an electrolyte imbalance or hyponatremia. AAGL guidelines for operative hysteroscopy using isotonic distention media such as normal saline recommend limiting the fluid deficit to 2,500 mL in order to restrict intravasation of significant volumes of fluid and thereby prevent the onset of dangerous sequelae associated with fluid overload such as right-sided heart failure, hypoxia, difficulty with ventilation, and pulmonary edema [2]. Electrolyte-rich fluids can be used with bipolar radiofrequency surgical instruments but are not an appropriate fluid of choice for monopolar radiofrequency surgical instruments due to the dispersion of current.

For patients with compromised cardiovascular systems or who are elderly, the AAGL recommendation is to limit the maximum fluid deficit to 750 mL, regardless of the composition of the distention medium.

1.5 Office Hysteroscopy

The most common use of diagnostic office hysteroscopy is to evaluate both pre- and postmenopausal patients who complain of abnormal uterine bleeding (AUB) for intracavitary pathology. Additionally, systematic evaluation of the uterine cavity can be helpful in diagnosing unsuspected abnormalities in infertility patients [3,4]. The advantage for the physician is an expedited pathway to diagnosing and treating the etiology of the AUB and/or infertility via a safe procedure with few complications. For the patient, resumption of daily activities begins immediately and the risks of undergoing anesthesia are avoided.

Patients should be selected appropriately for office hysteroscopic procedures. Select those who are ASA Class I or II, whose procedures are not complicated, and can be completed successfully within a brief period of time. Avoid patients who have poor pain tolerance or unrealistic expectations of in-office procedures. Further considerations regarding cardiac and pulmonary medical history should be taken into account if moderate or deep sedation is involved.

1.6 Choice of Analgesia

The choice of anesthesia is surgeon dependent. The options range from NSAIDs to combinations of intravenous (IV) or general anesthesia with or without adjunct administration of local anesthesia. Surgeons may choose to avoid a paracervical block secondary to the discomfort caused by performing the block itself, which is not insignificant. Moreover, potential complications from local anesthesia can occur when patients are given an overdose of the analgesia, have an allergic reaction, or when the analgesia is inadvertently injected intravascularly. Manifestations of systemic injection include dizziness, tremor, oral paresthesias, blurry vision, and seizure. More serious sequelae include bradycardia secondary to myocardial depression, as well as respiratory depression and apneic episodes. To reduce the risks associated with systemic injection, the addition of epinephrine (1:100,000) can be used to enhance local vasoconstriction and thereby minimize the absorption of the analgesic.

If vaginoscopy is not performed, a total infiltration of 20 mL of a local anesthetic (such as 1% lidocaine buffered with 2 mL sodium bicarbonate) can be used as a paracervical block. The block consists of the following technique: 2 mL injected superficially into the anterior lip of the cervix at the 12 o’clock position prior to placement of a tenaculum, and the remaining 18 mL injected at the 4 o’clock and 8 o’clock positions along the cervicovaginal junction (9 mL at each site). Maximum dosing should not exceed 4.5 mg/kg of 1% lidocaine without epinephrine, or 7 mg/kg of 1% lidocaine with epinephrine.

1.7 Cervical Ripening Agents

Cervical dilation is the first step at the commencement of an operative hysteroscopic procedure to gain access to the uterine cavity. Some surgeons may elect to pretreat with cervical ripening agents in an effort to gain easier passage through the endocervical canal. Nearly 50% of hysteroscopic complications are related to difficulty of entry into the cervix. Thus cervical ripening can reduce complications associated with difficult entry such as creation of a false passage, cervical lacerations, and uterine perforation.

A commonly used cervical ripening agent is synthetic E1 prostaglandin (PGE1) known as misoprostol. Its administration in 200–400 mcg tablets taken orally or vaginally 12–24 hours before surgery for cervical ripening is considered an off-label, investigational use in the United States despite the existence of high-quality evidence from RCTs that suggest it improves cervical dilation as well as decreases the risk of traumatic entry in premenopausal patients [5]. In postmenopausal women, there is evidence to suggest that pretreatment with 25 µg of vaginal estradiol for 2 weeks in combination with 400 µg of vaginal misoprostol 12 hours prior to the procedure can help facilitate cervical dilation in hysteroscopic procedures [6,7]. Side effects of misoprostol include fevers, chills, vomiting, diarrhea, vaginal bleeding, and uterine cramping. Other options include a natural prostaglandin E2 (PGE2) known as dinoprostone, or hygroscopic dilators that are placed within the endocervical canal. Hygroscopic dilators gradually dilate the endocervical canal radially via osmosis-induced expansion over a period of hours and may be a good option for women with contraindications to prostaglandin use; however, the limited available evidence is mixed regarding the efficacy of this method [5]. Given that laminaria require time to hydrate and dilate, this method requires an office visit the day prior to surgery or at least 6 hours pre-operatively for intracervical placement.

Injection of a dilute solution of vasopressin (0.05–0.2 U/mL of normal saline) can also promote cervical dilation as well as improve hemostasis by inducing contraction of the myometrium, thereby decreasing the fluid absorption. Associated toxicity can include arrhythmias. This technique consists of a total of 8–10 mL of dilute vasopressin, with 4–5 mL injected intracervically at 3 o’clock and at 9 o’clock positions. See “Vasopressin Administration” section under Hysteroscopic Myomectomy for further details.

It is rarely necessary to soften the cervix for office hysteroscopy due to the narrow diameter of the hysteroscopic equipment. The surgeon must beware that oversoftening of the cervix will make it difficult to maintain uterine distention during the hysteroscopic procedure.

1.8 Hysteroscopic Lysis of Adhesions

Intrauterine adhesions, interchangeable with the term Asherman’s syndrome, typically present secondary to trauma of the basalis layer of the endometrium. This most often occurs after a uterine curettage for management of postpartum hemorrhage or incomplete spontaneous abortion. However, they can also develop after common procedures such as hysteroscopic myomectomy. Granulation tissue forms secondary to the trauma and creates tissue bridges between the walls of the uterine cavity, resulting in occlusive adhesions.

1.8.6 Surgical Technique

See Video 1.1

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   1. Place patient in the dorsal lithotomy position.

   
   
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   2. Perform pelvic exam to determine the position and size of the uterus.

   
   
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   3. Sterile prep the patient.

   
   
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   4. Using the vaginoscopic technique, the hysteroscope is introduced into the vagina and distend the vaginal vault with normal saline. Slowly raise your hand to lower the tip of the scope into the posterior fornix, directly visualizing the upper third of the vagina as you pull back to locate and visualize the external os. Guide the scope into the endocervical canal and drop your hand toward the ground to keep the internal os centralized at the 12 o’clock position in order to avoid digging the scope into the posterior wall of the endocervical canal. Do not advance the scope with force if you are met with resistance as this can result in formation of a false passage. Successful entry into the cavity is achieved by placing one hand on the light cord and the other on the camera while rotating the entire scope back and forth between 4 o’clock and 8 o’clock positions and advancing gently along the axis of the cervical canal.

   
   
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   5. Once the uterine cavity is entered, obtain a panoramic view to assess the extent of adhesive disease and locate any lesions if present (Figure 1.1). Take a systematic approach and note if either ostium is visible. Classify the severity of adhesive disease by the degree of uterine cavity involvement as described earlier. With more significant adhesive disease, anatomic landmarks are no longer recognizable and make spatial positioning difficult. In those cases, intraoperative transabdominal ultrasound guidance can be helpful.

Figure 1.1 Hysteroscopic view of fundal adhesions.

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   6. Advance the blunt-tipped scissors, using both the sharp dissection to take down synechiae as well as blunt dissection by spreading the tips of the scissors (Figure 1.2). If you encounter bleeding, this is a cue that you are no longer dissecting scar tissue and have encountered the myometrium. Continue adhesiolysis until the normal cavity is restored (Figure 1.3). In cases with obliterated cornua, it may be difficult to visualize the tubal ostia after adhesiolysis secondary to the small size of the ostia.

Figure 1.2 Lysis of intrauterine adhesions with scissors.

Figure 1.3 Restoration of the uterine cavity.

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   7. While extracting the hysteroscope, evaluate the endocervical canal.

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