Hysteroscopy is performed to view and treat pathology within the uterine cavity and endocervix. Diagnostic hysteroscopy allows visualization of the endocervical canal, endometrial cavity, and fallopian tube ostia. Abnormal findings may include polyps, leiomyomas, intrauterine adhesions, hyperplasia, malignancy, foreign bodies, retained products of conception, and müllerian anomalies. Operative hysteroscopy incorporates the use of mechanical, electrosurgical, or laser instruments to treat intracavitary pathology and perform hysteroscopic sterilization procedures.
Diagnostic hysteroscopes are available in both flexible and rigid models, all of which contain a telescope consisting of light bundles. Flexible hysteroscopes range in diameter from 2.7 mm to 5 mm and have a bendable tip that can be deflected in two directions ranging from 100 degrees to 180 degrees. Rigid hysteroscopes may consist of two or three pieces and range from 1 mm to 5 mm in diameter. Their tips have varying viewing angles (0 degrees, 12 degrees, 15 degrees, 30 degrees, and 70 degrees). An outer sheath fits over the telescope to allow inflow of a distending medium into the uterine cavity. This system allows fluid to return on the outside of the outer sheath passively from the uterine cavity through the cervix. Continuous flow hysteroscopes consist of two channels to allow fluid to flow into the intrauterine cavity while debris and cloudy intrauterine fluid exit through perforations in the outer sheath to the outflow port. Fluid exiting the outflow port can be collected through tubing and returned to a collection canister for the accurate measurement of fluid volume. Flexible and rigid hysteroscopes may contain an operative channel for endometrial biopsy, tubal cannulation, or intrauterine surgery.
Operative hysteroscopes typically range from 8 mm to 10 mm in diameter and contain a retractable hand piece wherein electrosurgical tips (eg, rollerballs, loops, and vaporizing tips), laser devices, or mechanical instruments (eg, scissors or morcellators) may be attached. Currently, there are three types of operative hysteroscopes: the traditional model contains a retractable hand piece and is available as bipolar or monopolar device; a second type consists of a hysteroscopic morcellator (this type does not use electrosurgical energy to resect tissue), uses saline as the distention media, and resects tissue and suctions it to a canister; the third type of hysteroscope contains a bipolar electrosurgical hand piece that resects and removes tissue through the operative sheath, leaving few tissue fragments within the operative site.
The uterine cavity requires distention for adequate visualization. Several distending media are available and each has inherent advantages and disadvantages (see Table 1). It is critically important to understand which media are compatible with electrosurgical and laser energy. Furthermore, the risks associated with various media must be understood. High-viscosity media, such as dextran, have been used in the past, but they are generally not used now because of limitations, such as the fluid’s tendency to harden and crystalize onto the equipment, as well as an increased risk of anaphylaxis and disseminated intravascular coagulation.
Carbon Dioxide Gas
Carbon dioxide (CO2), a colorless gas, is used in outpatient settings for diagnostic purposes only. The advantages of its use include the ease of cleaning and maintaining equipment and a clear view of the cavity in the absence of active bleeding or bubbles. To minimize the risk of gas embolization, the flow of CO2 should be limited to 100 mL/min with intrauterine pressure less than 100 mm Hg and used with a hysteroscopic insufflator. Insufflators designed for use in laparoscopy must not be used for hysteroscopy.
Fluid media have historically been divided into electrolyte media and nonelectrolyte media, based on compatibility with the electrosurgical device used. However, it is now possible to use electrolyte media with bipolar electrosurgical systems. It also is important to understand which media are hypo-osmolar.
Electrolyte-poor fluids in-clude glycine, 1.5%; sorbitol, 3%; and mannitol, 5%. These fluids have been widely used for operative hysteroscopy. They are compatible with radio-frequency energy, which cuts, desiccates, and fulgurates intrauterine tissue. Monopolar devices require electrolyte-poor fluids. If electrolyte-containing fluid is used, the electrical current will dissipate away from the electrode, rendering it ineffective. Glycine, 1.5%, and sorbitol, 3%, are hypo-osmolar. Excessive absorption of these fluids can cause hyponatremia, hyperammonemia, and decreased serum osmolality, with the potential for seizures, cerebral edema, and death (1). Some clinicians have recommended mannitol, 5%, which is iso-osmolar and acts as its own diuretic. It may cause hyponatremia, but not decreased serum osmolality (2).
Normal saline solution and lactated Ringer’s solution are electrolyte fluids. The use of these fluids is advantageous because they are readily available and are isotonic. These solutions are the distending media of choice during diagnostic hysteroscopy and in operative cases where mechanical, laser, or bipolar energy is used. Although the risk of hyponatremia and decreased serum osmolality can be reduced by using these media, pulmonary edema and congestive heart failure can still occur. Careful attention should be paid to fluid input and output, with particular attention to the fluid deficit.
A preoperative consultation allows the patient and physician to discuss the hysteroscopic procedure, weigh its inherent risks and benefits, review the patient’s medical history for any comorbid conditions, and exclude pregnancy. Appropriate analgesia or anesthesia also should be considered depending on the venue (ie, office versus operating room). Preoperative placement of laminaria or osmotic dilators or pretreatment with misoprostol for cervical ripening may facilitate cervical dilation and decrease operative time and pain (3–6). Antibiotic prophylaxis is not recommended for hysteroscopy (7).
In premenopausal women with regular menstrual cycles, the optimal timing for diagnostic hysteroscopy is during the follicular phase of the menstrual cycle after menstruation. Hysteroscopy during the secretory phase of the cycle can make diagnosis more difficult because the endometrium is thick and can mimic polyps. Some women with unpredictable menses can be scheduled at any time for operative hysteroscopy.
Office hysteroscopy is becoming increasingly common because of smaller-diameter telescopes, excellent analgesia protocols, and increased convenience and cost-effectiveness compared with operating room procedures (8, 9). Equipment generally needed to perform hysteroscopic procedures in the office includes a hysteroscope with an outer sheath of less than 5 mm in outer diameter, distending media and infusion system, operative instrumentation, and a light source. Although it is possible for the surgeon to look directly into the eyepiece, cameras and video monitoring systems make it possible to obtain photographs and video and enable the patient to see images.
Major barriers to successful office hysteroscopy include pain, cervical stenosis, and poor visualization of the cervix (10). Therefore, preoperative patient selection and counseling are very important. Poor candidates for office hysteroscopy include patients who have cervical stenosis, high levels of anxiety, comorbidities, limited mobility, or significant uterine pathology requiring operative procedures. Office hysteroscopy should be brief and usually consists of either diagnostic or minor operative procedures. Off-label administration of oral or intravaginal prostaglandin (misoprostol, 200–400 micrograms) the night before surgery, preoperative administration of nonsteroidal antiinflammatory medications or antianxiety medications, paracervical anesthetic block, the use of narrow-caliber hysteroscopes (less than 5 mm in diameter) and flexible hysteroscopes, and assistance of a dedicated office staff may facilitate these procedures (4, 10). Although data on the use of misoprostol with hysteroscopy are limited, buccal or sublingual misoprostol has been found to be more effective than vaginal misoprostol in other settings, such as postmenopausal dilation and curettage (D&C) or suction D&C associated with first-trimester pregnancy termination (11–14). When introducing any invasive technology, such as hysteroscopy, into the office setting, it is imperative to institute rigorous patient safety measures. See the American College of Obstetricians and Gynecologists’ Patient Safety Task Force report (15).
Known pregnancy, genital tract infections, and active herpetic infection are contraindications to hysteroscopy. Hysteroscopy usually is not performed in patients with advanced stage uterine or cervical cancer who are at risk of hemorrhage or dissemination of tumor cells. Hysteroscopy may cause reflux of neoplastic cells into the peritoneal cavity, although it is unclear if this adversely affects the prognosis (16, 17). However, hysteroscopy is acceptable as part of the evaluation of abnormal uterine bleeding.
Prevention and Management of Complications
The most common perioperative complications associated with operative hysteroscopy are hemorrhage (2.4%), uterine perforation (1.5%) (18), and cervical laceration (1–11%) (19). Complications from fluid overload should be considered as well. Other complications include visceral injury, infection, CO2 and air embolism, and, rarely, death. Delayed complications may include intrauterine adhesions and infertility.
Hemorrhage may occur during hysteroscopic resection of the endometrium, leiomyomas, uterine septa, or synechiae and from cervical lacerations or uterine perforation. Delayed hemorrhage may be seen among patients with endometritis weeks after surgery. For patients with continued intraoperative bleeding, electrosurgical coagulation can be used if a bleeding site can be visualized (1). Alternative strategies, such as injection of vasopressin into the cervical stroma, Foley catheter balloon tamponade (20), or uterine compression, can be attempted. In extreme cases, laparoscopic suturing of a perforation, hysterectomy, or uterine artery embolization may be necessary.
Complications from fluid overload may best be avoided by anticipation and preoperative evaluation of size and number of lesions to be removed. Fluid absorption is affected by size and number of the lesions removed, the depth of myometrial resection, the number of myometrial sinuses opened, and the intrauterine pressure. Complications may be prevented by limiting excess fluid absorption, recognizing and treating fluid overload promptly, and selecting a distending medium that minimizes risk. Vasopressin injection in the cervical stroma may reduce the volume of fluid intravasation (21). The best way to limit excess fluid intravasation is to monitor the fluid deficit closely and frequently throughout the procedure. During long and difficult cases, the surgeon may work with anesthesiologists to maintain awareness of the deficit and manage the rate and volume of intravenous fluid infusion from the head of the operating table. Fluid absorption should be carefully and frequently monitored by a designated individual.
Newer methods, based on measurement of fluid weight, have made fluid monitoring more accurate; however, some of these systems can be expensive and may not be available in all settings. One difficulty in estimating fluid input and output is that commercially purchased 3-liter bags may be overfilled by up to 150–300 mL (22). Dilutional hyponatremia can be rapidly evaluated by serum sodium analysis.
Guidelines for fluid monitoring and the limits of fluid excess have been published (2) and adapted by the American College of Obstetricians and Gynecologists’ Committee on Gynecologic Practice as follows:
- Intravenous hydration of patients undergoing hysteroscopy should be closely monitored preoperatively and intraoperatively. Hysteroscopic fluid absorption should be closely monitored intraoperatively.
- Lower fluid deficit thresholds should be considered for elderly patients, patients with comorbid conditions, patients with cardiovascular or renal compromise, and when procedures take place in an outpatient setting with limited acute care and laboratory services.
- In healthy patients, the maximum fluid deficit is 1,000 mL for hypotonic solutions, 2,500 mL for isotonic solutions, and 500 mL for high-viscosity solutions. However, if fluid deficit reaches 1,000 mL of a hypotonic solution, 2,000 mL of an electrolyte solution, or 300 mL of a high-viscosity solution, consideration should be given to stop further infusion and conclude the procedure. Electrolytes should be assessed, administration of diuretics considered, and further diagnostic and therapeutic intervention begun as indicated (2).
- In an outpatient setting with limited acute care and laboratory services, consideration should be given to discontinuing procedures at a lower fluid deficit threshold than indicated earlier.
- An automated fluid monitoring system facilitates early recognition of excessive deficit in real-time totals.
- An individual should be designated to frequently measure intake and outflow and report the deficit to the operative team.
The treatment of fluid overload from hypotonic agents may require consultation and possibly a patient transfer to an urgent care facility. Whereas most women recover, seizures, permanent brain damage, and death have been reported with serum sodium levels of 116 mmol/L plus or minus 2 mmol/L (23). Although the rate at which severe hyponatremia should be corrected is controversial, most authors agree that if acute hyponatremia has existed for less than 24 hours, there are few long-term complications from rapid correction. Therapy is most often provided in the form of hypertonic saline solution in conjunction with loop-acting diuretics, such as furosemide. Serum sodium levels should be increased by 1–2 mEq/L/h, but by no more than 12 mEq/L in the first 24 hours (24). When patients present with hyponatremia of greater than 48 hours’ duration postoperatively, rapid correction should not be undertaken because it can lead to neurologic compromise, seizures, and death. Consultation is strongly encouraged in these situations and often requires slower correction in an intensive care setting.
Before performing hysteroscopy, the clinician should perform a pelvic examination to determine uterine position. Ultrasound guidance may be useful in difficult cases. If resistance is encountered during insertion of the hysteroscope, the cervix may need further dilation. If a flexible hysteroscope is available, it should be used before attempting forceful dilation with larger dilators or placement of a hysteroscope. The flexible hysteroscope often can be placed without need for cervical dilation and permits a physician the ability to determine the angle of inclination of the cervix and trajectory taken when cervical dilation commences. Midline uterine perforation rarely leads to significant morbidity unless a laser or electrosurgical device is used. Lateral uterine perforations can lead to the development of a retroperitoneal hematoma, and cervical perforations can result in significant immediate or delayed bleeding. Laparoscopy may be useful to determine the extent of damage, including the existence of bowel injury or bladder injury.
Air and CO2 emboli are rare complications of hysteroscopy that may result in circulatory collapse. Preventive strategies include flushing air from tubing and making sure that the procedure is stopped and tubing is purged of air when bags are changed. For such emboli to occur, there must be both vascular access and a pressure gradient between the site of access and the right side of the heart. In the conscious patient, chest pain and dyspnea may be noted. Other findings can include decreased oxygen saturation, the presence of a “mill wheel” heart murmur, hypotension, bradycardia, or tachycardia. In the anesthetized patient, cardiopulmonary status shows signs of collapse with sudden hypotension, decrease in oxygenation or end-tidal CO2 or both, or cardiac dysrhythmias (25).
Management of this emergency consists of placing the patient in a left lateral decubitus position with the head tilted downward 5 degrees. This maneuver favors the movement of air in the right ventricle and right ventricular outflow tract toward the apex of the right ventricle (26). The air may be aspirated by passing a catheter down the jugular vein into the right ventricle, or possibly by performing cardiocentesis.
Hysteroscopy is an effective procedure for the diagnosis and treatment of intrauterine pathology. It is minimally invasive and can be used with a high degree of safety. Knowledge of potential risks relating to distending media and intraoperative complications will enhance its safety.
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