Hysteroscopy |
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INTRODUCTION |
The hysteroscope is a telescope attached to a light source, which then is passed into the uterine cavity by way of the endocervical canal. It was initially described by Pantaleoni in 1869 but did not achieve routine gynecologic use due to its poor optic system. However, in the last 25 years refinement in optical and fiberoptic instrumentation, along with operative accessories, has dramatically improved visual resolution and operative technique. Today, many hysteroscopic procedures have replaced older, more invasive techniques.
The hysteroscope consists of 3 parts: the eyepiece, the barrel, and the objective lens. There also are different types of light sources: tungsten, metal halide, and xenon. A xenon source with a liquid cable is considered the superior option (ACOG, 1994; Shapiro, 1988). Most hysteroscopes have the capacity to input media and drain media in order to control for volume and visibility in clearing bubbles from the view. The focal length of the instrument is important for visualization. The tip of the hysteroscope can have different angles, which allow for improved or specific visualization. The angle options are 0, 12, 15, 25, 30, and 70 degrees.
A 0-degree hysteroscope allows for a distant panoramic view, while an angled one might give a better view of the ostia in an abnormally shaped endometrium. The scopes also come in different styles: rigid, contact, micro, and flexible.
Available in a range of diameters. The narrow option is 3-5 mm. These can be used in the office setting because they require minimal dilation of the cervix. A paracervical block without need for anesthesia makes them ideal for office hysteroscopy. Of these, the 4-mm scope offers the sharpest and clearest view. It is optimal for use because of its small diameter and its allowance for operative instruments. Those scopes that are greater than 5 mm in diameter can accommodate more specific surgical instruments through separate ports. The large-caliber 8-10 mm scopes maintain optical integrity, with superior visibility due to the continuous laminar flow of media. All of these scopes require an outer sheath for introduction and removal of media, as well as for accommodating instruments. An obturator can be used for placement of the sheath through the cervix.
A simple, rigid scope with a single glass column; it needs no sheath. The hysteroscope conducts light to the surface, producing an image. The tissue is in focus with direct contact, and no media is required for its use. It does have a limited view, with no panorama, and nearly microscopic image. It can be used only for diagnostic evaluation. Color, architectural pattern, contour, and feel can be assessed. This instrument is available in different sizes, as well: 4-, 6-, or 8-mm diameter. It is the easiest of the scopes to use as it does not require dilation or infiltration of media, but it gives by far the most difficult findings to interpret. This is a highly specialized instrument that primarily is used in a research setting.
Converts panoramic viewing to high-powered microscopic pictures with lenses up to X150 magnification. This instrument is used with an outer sheath and also requires contact with tissue for visualization. Distention media is not needed for microscopic viewing. Due to its specific function and lack of versatility it rarely is used in the clinical arena.
The flexible hysteroscope has a tip that can deflect over a range of 120-160 degrees. Its most appropriate use is for the irregularly shaped uterus. It does decrease discomfort as it accommodates to the cervix more easily during insertion. The view often is described as having a ground glass quality, which is markedly less desirable than the rigid scopes (Corfman, 1988). The flexible tip is advantageous for maneuvering around polyps or submucosal fibroids or for visualizing eccentrically placed ostia (Corfman, 1988). Directed biopsies are possible with this instrument and it has been used for transcervical tubocornual recanalization, chorionic villus sampling, and intrauterine device (IUD) retrieval (ACOG, 1994).
Operative instruments
Surgical instruments to be used with the hysteroscope are available in both rigid and flexible forms to be inserted through the operating channels of the scopes (eg, scissors, biopsy forceps, grasping instruments). Scissors have multiple applications including incising a septum, excising a polyp or pedunculated fibroid, or lysing adhesions (Corfman, 1988).
For histologic evaluation, the biopsy forceps can grasp tissue for pathologic review (Corfman, 1988). Grasping instruments have the ability to aid in the removal of foreign bodies, such as a retracted intrauterine device (Corfman, 1988). The rollerball or ball can be used for endometrial ablation. This instrument has a uniform coagulating current that desiccates the tissue as it is contacted. The loop has numerous uses, eg, it can shave the endometrial surface for ablation or resect a fibroid or septum. Another instrument is the knife, which concentrates its energy and can cut or coagulate at the tip. The surface area of the knife is small, so the power density is higher at the tip when compared to other instruments.
The resectoscope is a specialized instrument with a monopolar double-armed electrode with a trigger device. It causes an electrosurgical effect by contact desiccation through resistive heating (Brill, 2000). The depth of thermal damage is based on multiple factors including degree of endometrial thinning; speed, pressure, and duration of contact during motion; and power setting (Brill, 2000; Luciano, 1995). It is available with a 4-mm ball, roller barrel, ellipsoid, and 5-7 mm cutting loop. A thin electrode can cut tissue, whereas a larger surface area, such as a ball or barrel, is more suited for coagulation (Indman, 2000).
When using the blend waveform, as opposed to the cut option, hemostasis can be better achieved at the cut edges, allowing for improved visibility during operative procedures such as submucosal myomectomy and endomyometrial resection (Brill, 2000). When used with a 30-degree scope angled toward the electrode, clear visualization can be achieved during manipulation.
Newer technology, the VersaPoint system (Gynecare, Inc.), uses bipolar circuitry for electrosurgery. This system allows the use of various instruments with specific tissue effects: a spring tip for hemostatic vaporization of large areas, a ball tip for precise vaporization, and a twizzle tip for hemostatic resection and morcellation of tissue (Brill, 2000). The medium used for this system is an isotonic saline.
Two other options are available for surgical equipment for use with electrolyte-containing solutions: the ERA sleeve and OPERA STAR system. Both are modifications of the monopolar system and are safe for use with isotonic saline or lactated Ringer solutions.
Lasers
Several fiberoptic lasers are available for gynecologic use. The potassium-titanyl-phosphate (KTP) and argon lasers have different wavelengths, 0.532 痠 and 0.458-0.515 痠, respectively but have very similar effects. Both are visible as green light and can pass through flexible fibers and fluid. They are absorbed by darkly pigmented tissue and penetrate to a 1- to 2-mm depth with minimal scatter. Both are effective in cutting tissue, but the argon laser has the unique effect of blowing smoke, odor, fluids, and blood out of the area of use, increasing its visual field of operation (Luciano, 1995).
The neodymium:yttrium-aluminum-garnet (Nd:YAG) laser, with a wavelength of 1.064 痠, also can pass through flexible fibers and fluid. It transmits easily through liquid media and is not absorbed by water or clear tissue, but it penetrates deeply into tissue before being absorbed, scattering on contact, thus making it poor for cutting but good for coagulation. The necrosis of the tissue is self-limited to 4 mm in all directions (Brill, 2000). A sculpted sapphire tip or sculpted quartz fiber can focus the beam and be used as a laser scalpel; however, the tip cannot be cooled with gas (Corfman, 1988), and the sapphire tip is contraindicated for intrauterine operations (Luciano, 1995).
Media
The use of media is critical for panoramic inspection of the uterine cavity. Without media, the uterus is a narrow slit. Intrauterine pressures needed to adequately view the endometrium are proportional to the muscle tone and thickness of the uterus. A pressure of 75 mm Hg is adequate for uterine distention. Rarely is more than 100 mm Hg required, and higher pressures can result in increased risk of intravasation of media (Marlow, 1995). The refractive index of each medium option affects magnification and visualization of the endometrium.
Media leakage can occur through the cervix, tubal ostia, hysteroscopic channels, and uterine vessels. An inner sheath can be used for inflow of media with a larger outer sheath, which can have perforations to allow for outflow of media in order to keep the visual field clear (Corfman, 1988). The delivery system can be via closed or open system, with the former using fluid returned through a pump to a reservoir and the latter allowing free flow of the media out through the cervix into a collection bag for volume monitoring. For clearer visibility, an optional active suction can be placed at the outflow to clear debris from the field when needed.
Different kinds of delivery systems are suited to the various types of media. The simplest is a syringe that most often is used with the high-viscosity dextran 70. A hanging gravity-fed container that can be raised or compressed with a cuff can be unreliable for pressures. Pumps also are available that monitor pressure and volume for low-viscosity media.
Gases
Carbon dioxide has been used since 1920, when it was added by Rubin during tubal perflation (Shapiro, 1988). The refractory index of CO2 is 1.0, which allows for excellent clarity. CO2 primarily is employed for diagnostic hysteroscopy. CO2 is rapidly absorbed and easily cleared from the body via respirations; it allows a wider field of view at lower magnification. A small scope can accommodate the gas, as the gas can flow through narrow operative channels, making anesthesia and cervical dilation unnecessary. But CO2 does require an insufflator specific for hysteroscopy to regulate flow and limit maximal desired intrauterine pressure. It should be noted that laparoscopic insufflators are not safe.
Usually, a flow rate to 40-60 mL/min at a maximum pressure of 100 mm Hg is accepted as safe. Higher pressures and rates can result in cardiac arrhythmias and arrest (Shapiro, 1988). The advantages of CO2 are its relatively low toxicity profile, rapid absorption, and lack of destruction to instruments. Its disadvantages are the inability to clear the lens when bleeding occurs, resulting in loss of a clear visual field and limited visualization, and the risk of embolization with exposed blood vessels.
Fluids
The advantage of fluid over gas is the symmetric distention of the uterus with fluid, as well as its capacity to flush blood, mucus, bubbles, and small tissue fragments more effectively out of the visual field. Both low-viscosity and high-viscosity fluid media can be used for distention.
There are 2 types of electrolyte-containing fluids: saline (0.9% sodium chloride, which is 154 mEq/L of sodium and chloride) and acetated Ringer solution. These solutions can be used for diagnostic hysteroscopy as well as for limited operative procedures. Operative procedures using mechanical, laser, or bipolar energy are safe. Both options are readily available, and complex equipment is not needed.
There are 2 major disadvantages associated with these solutions: they are miscible with blood, obscuring visibility with bleeding, thus requiring larger volumes to clear the operative field, and they are excellent conductors, which precludes procedures that use electrosurgery. But it is important to note that new equipment has been developed that allows for surgical procedures in the setting of these solutions, ie, VersaPoint, ERA sleeve, and the OPERA STAR system. The nonelectrolyte fluids consist of 5% mannitol, 3% sorbitol and 1.5% glycine. These fluids do not conduct electrical current and allow for better visualization when bleeding occurs.
The common disadvantage of all of the nonelectrolyte media is their risk of overload from intravascular absorption (particularly >2 L), requiring fluid monitoring during use. All of these fluids are isotonic solutions that can be applied for diagnostic as well as operative hysteroscopy. However, 5% mannitol can be used only with monopolar operative procedures. It is broken down by the liver to glycogen and excreted through the kidney, with a half-life of 100 minutes (Marlow, 1995).
If 5% mannitol is given intravenously, it remains in the extracellular compartment. When intravasation occurs with this media, fluid and electrolyte imbalances can result in pulmonary edema, which can be treated with a diuretic (Marlow, 1995). The 3% sorbitol is broken down by the liver to fructose and glucose, which increases postoperative risks of hyponatremia and hyperglycemia. A dilutional hyponatremia also can occur with fluid overload of 1.5% glycine. Caution should be taken when this is used in a patient with impaired hepatic function because glycine is metabolized to ammonia and serine.
The only high-viscosity medium available is dextran 70 or Hyskon, which is 32% dextran 70 in 10% dextrose in water. Dextran is a high molecular weight substance of 70,000. It is a nonelectrolytic, nonconductive fluid that can be applied in operative and diagnostic procedures. Because of its high viscosity, dextran 70 is immiscible with blood and has minimal leakage through the cervix and tubes, allowing for excellent visibility during surgical procedures.
However, more than 500 mL of absorption must be avoided to prevent fluid overload, as it is a volume expander with a high risk of pulmonary edema. With each 100 mL of dextran 70 absorbed, the intravascular volume is increased by 800 mL (Marlow, 1995; Cooper [early], 2000). This medium has a large adverse effect profile including allergic reactions and anaphylaxis, fluid overload, disseminated intravascular coagulopathy, and destruction of instruments (which need to be cleaned shortly after use as the solution can stick to the equipment).
History of the Procedure: The first hysteroscopic surgery was reported in 1869 by Pantaleoni (Marlow, 1995). Then, in 1925, CO2 was added by Rubin during evaluation of tubal patency (Marlow, 1995). In the 1970s, hysteroscopy became a common procedure used for office sterilization, and in the 1980s, distention media was used with hysteroscopy for endometrial ablation (Marlow, 1995). By the mid 1980s, hysteroscopy nearly replaced dilation and curettage (D&C) for diagnosis of intrauterine pathology and now is considered an integral part of residency training programs (Jansen, 2000). The resectoscope is a modified instrument initially used by urologists for transurethral prostatectomy.
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INDICATIONS |
Abnormal uterine bleeding
Hysteroscopy has nearly replaced standard D&C for the management of abnormal uterine bleeding. D&C specimens have been reported to sample only 50% of the endometrium in 60% of patients, missing lesions 10-35% of the time (Corfman, 1988). Hysteroscopy allows for direct visualization of intrauterine abnormalities in patients with abnormal uterine bleeding and for specific treatment, often at the time of diagnosis (Cooper, 1999). Recurrence of symptoms after a D&C procedure is noted in up to 68% of patients (March, 1992). Many gynecologists have found directed biopsy with hysteroscopy superior to D&C (Corfman, 1988).
A full workup to rule out endocrine disorders, hormonal disorders, or premalignant or malignant pathology is required prior to effective treatment with hysteroscopy for patients with abnormal uterine bleeding (Cooper,[late], 2000). This can then be followed by preoperative evaluation with sonohysterogram or diagnostic hysteroscopy, which are up to 88% effective in identifying polyps and submucosal fibroids (March, 1992; Bradley, 2000).
Some feel that MRI studies are useful for evaluation of intrauterine pathology, but MRI is a more expensive test (Gimpelson, 2000). Some studies report better results and decreased adhesion rates after pretreatment with a gonadotropin-releasing hormone (GnRH) agonist or Depo-Provera on day of surgery to induce a hypoestrogenic state (March, 1992). The long-term success with satisfactory results after hysteroscopic removal of fibroids and polyps is 80-85% (Blanc, 1996). Recurrence of symptoms is noted most commonly with larger uterine size and increased number of fibroids (Emanuel, 1999).
For patients for whom fertility is not an issue and endometrial atypia has been ruled out, endometrial ablation has become an acceptable alternative to hysterectomy. In the short term, ablation for a benign disorder results in amenorrhea in approximately 30% of patients (Cooper, [late], 2000; Probst, 2000; Daniell, 1992). Most studies state that of postablation patients, 26% will have spotting, 34% will have a decreased flow, and 10% will have no change or an increase of their symptoms (Cooper, [late], 2000).
The long-term effectiveness of endometrial ablation for indications of menorrhagia or fibroids is 60-90% (Cooper, [late], 2000; Probst, 2000; Daniell, 1992), with 90% of patients noting an overall decrease in flow and amenorrhea that results in 30-50% of cases (Schenk, 1999). Those patients who are taking estrogen still require progesterone for endometrial protection from estrogen-induced endometrial changes (March, 1992).
Ablation can be performed using electrocautery with a resectoscope, laser, or thermal catheters (March, 1992; Shapiro, 1988; Singer, 1994). De Cherney reported using the resectoscope with 30 watts of coagulation as an alternative means of managing intractable uterine bleeding (De Cherney, 1987). With the rollerball ablation, the amount of thermal damage correlates linearly to the amount of wattage in cutting or coagulation modes (Onbargi, 1993).
When using the cutting or unmodulated mode, one needs greater than 90 watts for 3-mm depth compared to coagulation or modulated mode, which requires only 55 watts for the same results (Onbargi, 1993). However, higher levels did not result in a significant difference in depth of damage, with a maximum at 4.2 mm depth or 19% of myometrium (Onbargi, 1993). Even with pressure applied by the ball onto the endometrium, the ball cannot penetrate the wall of the uterus (Vancaillie, 1989). Although a higher wattage is used in the unmodulated mode, most prefer it to the modulated mode (Onbargi, 1993).
Fibroids
Fibroids are the most common solid pelvic tumor in women, found in 20% of women older than age 35 years (March, 1992). Women with fibroids are at risk of abnormal uterine bleeding, as well as risks in pregnancy. These include poor implantation sites and restriction of normal uterine enlargement, resulting in preterm labor and miscarriage (March, 1992). Menorrhagia from symptomatic submucous fibroids is the most common indication for surgery (Vercellini, 1999). The heavy bleeding possibly is due either to the increased surface area of the endometrium or by prostaglandin synthesis (Tulandi, 1999).
Submucosal fibroids can be definitively diagnosed by diagnostic hysteroscopy ( Tulandi, 1999). Operative hysteroscopy is very effective in treatment of symptomatic fibroids, with 16% of treated patients requiring further surgery (ACOG, 1994). The advantage of hysteroscopic myomectomy is in avoiding laparotomy, uterine incision, and hospital stay (Schenk, 1999). There are several different instruments that often are used for hysteroscopic myomectomy. They include the resectoscope, scissors, and the laser.
The laser allows for vaporization of the fibroid instead of shaving, as with the resectoscope, which eliminates the need to remove resected tissue from the visual field (Tulandi, 1999; Gimpelson, 2000). The Nd:YAG laser is expensive and not always readily available, and the scissors may result in more bleeding, as they are less hemostatic, which makes the resectoscope the most commonly used instrument for hysteroscopic myomectomy (Tulandi, 1999).
Neuwirth and Amin were the first to report use with the resectoscope for removal of submucous fibroids (Tulandi, 1999). If the fibroid predominantly is submucosal, then complete resection is possible; but intramural fibroids tend to be difficult to resect completely. When a pedunculated or submucosal fibroid of less than 7 cm is removed there can be pieces that are more than 4-5 cm in diameter, which may require morcellation for passage through the cervix (Vercellini, 1999).
Sometimes a 2-step procedure is needed in order to resect a partially intramural fibroid, and the resectoscope is ideal for these cases (Gimpelson, 2000). During the first step, the fibroid can be resected to the level of the endometrium or just below, and the second step, performed 2 months later, can resect the remainder of the fibroid (Vercellini, 1999). Hysteroscopic myomectomy is especially effective if the fibroid is less than 3 cm (Schenk, 1999; Vercellini, 1999).
Resection of a completely intramural fibroid poses the risk of intravasation of media due to prolonged procedure time (Vercellini, 1999). If intramural component of the fibroid is greater than 50%, the patient is at risk for recurrent symptoms (Vercellini, 1999). Some advocate obtaining a MRI preoperatively in order to evaluate the intramural component (March, 1992).
Contraindications: There are accepted contraindications to hysteroscopic myomectomy. If the uterus is greater than 12 cm in depth, the media used does not distend the cavity appropriately (Tulandi, 1999). Other contraindications include a suspicion of endometrial hyperplasia, carcinoma, leiomyosarcoma, upper genital tract infection, or severe medical contraindications to surgery (Tulandi, 1999).
Some gynecologists use vasopressin injected into the cervical stroma before the procedure in an attempt to decrease blood loss and operative time (Tulandi, 1999). Pretreatment with a GnRH agonist has been shown to stabilize anemia, decrease fibroid size, decrease endometrial thickness, and decrease uterine vascularity (March, 1992; Schenk, 1999). It also can cause the uterus to decrease in size compared to the fibroid and thus decrease the cervical canal, which can make dilation more difficult (Gimpelson, 2000). Postoperative use of estrogen has been found to decrease adhesion formation (March, 1992; Schenk, 1999).
Intrauterine adhesions
Asherman syndrome was identified in 1948 as uterine synechiae (Goldrath, 1995). These intrauterine adhesions often are associated with amenorrhea or infertility. Hysteroscopy can be used for diagnosis and treatment of these adhesions. The filmy adhesions often are lysed with media alone, whereas the dense ones often require cutting or excision with blunt, sharp, electrocautery or laser (Shapiro, 1988).
Direct visualization of the uterine cavity allows for directed lysis (March, 1992; Schenk, 1999; Shapiro, 1988). If extensive lysis is indicated, laparoscopy can be used as an aid for decreasing the risk of perforation by visualizing the illuminated cavity intraabdominally (March, 1992). If the patient𠏋 symptoms include abnormal bleeding, hysteroscopic treatment results in a 88-98% return to normal menstrual cycles (March, 1992; Schenk, 1999), and if no other infertility issues are present 79% of treated patients will have normal pregnancies (75% of those with mild disease but only 31% with severe adhesions)(March, 1992). Hysteroscopic treatment can increase the risk of abnormal placentation (accreta, percreta, increta, and previa).
Postoperative stenting to prevent re-adhesion formation with a silastic stent or an IUD has been suggested, but copper IUDs may induce excess inflammatory reaction and the Progestasert may be too small for adequate results (March, 1992). Cook OB/GYN, Inc., provides a triangular balloon catheter that may provide better separation of the uterine walls at the cornua, during the healing phase (personal communication).
A Foley catheter placed into the uterine cavity with estrogen supplement (conjugated estrogen 5 mg x 25 d with medroxyprogesterone 10 mg x last 5 d) also has been used for stenting the cavity (Schenk, 1999). The purpose of the estrogen is to limit the amount of post-operative bleeding due to vasoconstriction of small blood vessels, and to rapidly rejuvenate the endometrial lining, which is less prone to form adhesions than a persistently raw, cut surface. If an intrauterine stent is used, antibiotic prophylaxis should be considered for the duration of the stent placement(March, 1992). Typically, oral doxycycline 100 mg twice daily is used. Also, the use of nonsteroidals will not only help with uterine cramping but has been shown to reduce adhesion formation in other pelvic procedures.
Follow-up hysterosalpingogram or diagnostic hysteroscopy following withdrawal bleeding has been recommended. Some authors have reported normal hysterosalpingogram studies in 90% of patients in follow-up (March, 1992).
Proximal tubal obstruction
No controlled studies have been done to support the efficacy of hysteroscopic treatment of proximal tubal obstruction for infertility. Many cases simply may be due to spasm (March, 1992). This is a difficult diagnosis to make. Theoretically, repair of proximal disease and removal of scar tissue is beneficial, and cannulation of the tubes can be performed at the same time (Schenk, 1999).
Removal of IUD
Hysteroscopy can be applied to remove an IUD under direct visualization after failed ultrasound guided retrieval (ACOG, 1994).
Mullerian anomalies
Some 1-2% of all women, 4% of infertile women, and 10-15% of patients with recurrent miscarriage have mullerian anomalies. These anomalies range from didelphys to mullerian agenesis. Uterine septum and in utero diethylstilbestrol (DES) exposure are more likely associated with miscarriage than is didelphys (March, 1992). Patients with a bicornuate uterus have a greater than 50% live birth rate compared with those with a uterine septum, which has a less than 30% live birth rate Bacsko, 1997. Patients with in utero DES exposure have the likelihood of a T-shaped uterus with corneal restriction bands, pretubal bulges, lower uterine segment dilation, and a small, irregular cavity with borders resembling adhesions (March, 1992). Hysteroscopy can confirm these findings but not treat them.
A uterine septum can be removed by hysteroscopy, and a hysteroscopic approach has reduced surgical complications compared with other procedures such as the Jones, Strassman, or Tompkins metroplasty (Bacsko, 1997). The first hysteroscopic resection of a septum was reported by Edstrom (Corfman, 1988). Bret and Guillet were the first to recommend incising versus excising the septum (Bacsko, 1997). There are equivalent rates of term pregnancy outcomes after hysteroscopic resection compared to metroplasty for uterine septum (March, 1992). The live birth rates after treatment are as high as 80% (Schenk, 1999).
Of patients undergoing hysteroscopic resection for mullerian anomalies, reports of dysmenorrhea postoperatively are only 20% compared to 50% with abdominal procedures (Bacsko, 1997). When performing hysteroscopic resection for uterine septum, bicornuate uterus must be ruled out. An MRI or sonohysterogram is capable of differentiating between a bicornuate or septum and have now replaced laparoscopy, except in situations where there is a need to evaluate the pelvis as in patients with pelvic pain or long-standing infertility. Hysteroscopy has a lower morbidity (Schenk, 1999), quicker operative time, and a perforation rate of approximately 1% (Bacsko, 1997).
Septal resection can be performed with scissors, laser, or the resectoscope (March, 1992). When the septum is less than 3 cm wide at the fundus, incising it from distal to cephalad causes the fibroelastic band to retract (March, 1992). This usually results in minimal bleeding (March, 1992). A broader septum requires a different approach. The first step is a lateral alternating technique of side-to-side resection up to 0.5 cm from the fundus (March, 1992). Then the remainder is removed from cornua to cornua to avoid damage to this area and to decrease bleeding. While resecting the septum, the laparoscope can be used to visualize the illuminated cavity. Another method is to visualize the procedure using a transabdominal ultrasound. This works better in thin women with anteflexed uteri. Also, the bladder usually needs to be full in order to better visualize the uterus. Incising a cervical septum is not recommended as it can result in cervical incompetence (March, 1992).
Some authors recommend using a uterine stent and estrogen postoperatively (Schenk, 1999), whereas others prefer only conjugated estrogen (1.25 mg x 25 d) with medroxyprogesterone (10 mg x last 5 days) (March, 1992). A follow-up hysterosalpingogram or office hysteroscopy also has been advocated (March, 1992). Preoperative GnRH agonists, gestagens, or danazol are not indicated if the procedure is performed in the early follicular phase as the endometrium is thin (Bacsko, 1997).
Infertility evaluation
Hysteroscopy is not part of the routine workup for infertility. However, it is appropriately indicated at the time of laparoscopy for the evaluation of unexplained infertility, as it not only can identify a possible etiology for the infertility or recurrent miscarriage but also can treat it at the same time (Corfman, 1988). It is indicated for evaluation of the cervix and uterine cavity as well to identify any possible abnormalities that might affect embryo implantation at the time of in vitro fertilization (Balmaceda, 1995). Intracavitary lesions are implicated as causes of infertility, and removal may increase fertility; but this has not been clearly documented (Vercellini, 1999). In contrast, for patients with recurrent miscarriage and intracavitary fibroids, surgery increases rates of viable pregnancy outcome (Vercellini, 1999).
Compared to hysterosalpingography, hysteroscopy is equivalent for evaluating the uterine cavity; however, the type of intrauterine filling defect was more accurately diagnosed with hysteroscopy (Corfman, 1988).
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RELEVANT ANATOMY AND CONTRAINDICATIONS |
Relevant Anatomy: For any hysteroscopic procedure it is imperative that the surgeon has an understanding of uterine wall thickness. This will allow the surgeon to manipulate the surgery based on the area of the uterus where he/she is operating. The following table lists the wall thickness for each area of the uterus. Keep in mind that the uterus is thicker in reproductive-aged women than in postmenopausal women.
Table 1. Uterine Wall Thickness
| Location | Mean (mm) | Range (mm) |
| Anterior wall | 22.5 | 17-25 |
| Posterior wall | 21 | 15-25 |
| Fundus | 19.5 | 15-22 |
| Isthmus | 10 | 8-12 |
| Corpus | 5.5 | 4-7 |
Contraindications: Contraindications for hysteroscopy depend on the procedure planned.
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WORKUP |
Lab Studies:
Imaging Studies:
Other Tests:
Diagnostic Procedures:
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TREATMENT |
Preoperative details: During the sonohysterogram, measurements of the uterine dimensions are helpful. Specifically, a uterine length greater than 10 cm makes the case difficult due to the length of the hysteroscope (typically 35 cm), which must traverse the length of the uterus, cervix, and vagina and be outside the introitus enough to attach the camera and manipulate the fluid inflow/outflow valves and the surgical instruments. Also, it is harder to maintain intrauterine pressures with larger cavities.
For large submucosal fibroids, the use of a GnRH agonist has been shown to decrease the uterine volume by approximately 30%, which may be enough to make the case technically easier, decrease blood loss, and prevent the need for a second procedure to remove any residual fibroid.
Prior to ablation procedures, the use of a GnRH agonist for ovulating women in the luteal phase of the prior menstrual cycle will improve visibility and provide a smooth, pale, hypovascular surface 3-4 weeks later (after the patient has her menses) that will make the procedure easier to perform and improve the success rate for the procedure.
For those who do not want a GnRH agonist, the simultaneous use of a GnRH antagonist along with progesterone at any point in the menstrual cycle theoretically will create a similar surface, once the patient has her menses, yet has fewer side effects and allows greater scheduling flexibility. One antagonist, Antagon (Ganirelix acetate, Organon, Inc.), comes packaged with gonadotropins for use in infertility therapy. However, Cetrotide (Cetrorelix, Serono, Inc.)comes packaged alone. This author has successfully used a single 3mg dose of Cetrotide given subcutaneously every 4 days along with provera (medroxyprogesterone acetate) 10 mg orally for 5 days.
Unlike the agonist, the antagonist's action is immediate, suppressing FSH and LH without any "flare" effect commonly seen with the agonist. The ablation procedure is then typically done after the patient completes her menses, which usually begins 2-3 days after the last progesterone tablet. A study is being done at the author's institution comparing the agonist and antagonist protocol.
Finally, suction curettage prior to the ablation will create a comparable surface as well. However, it appears to be most effective in the late luteal phase or during menstruation when the endometrium is loosely attached. In this author's experience the medical approaches are better.
Intraoperative details: The type of anesthesia used depends on the procedure, the level of patient anxiety, and the expertise of the anesthesiologist. Simple diagnostic procedures can be completed with just a mild sedative and paracervical block. For more extensive procedures or for patients with low pain tolerance, general or regional anesthesia is indicated.
The patient is placed in the dorsal lithotomy position and prepped and draped in a sterile manner. Unless a laparoscopy also is planned, the patient's thighs should be at a 90-degree angle to the pelvis in order to create enough space for the surgeon to manipulate the hysteroscope. The patient𠏋 perineum should be just past the edge of the table with the coccyx and sacrum well supported on the flat surface of the table. The patient's legs should be secured in the leg stirrups to avoid any abrupt movements, which could cause nerve or muscle injury to the patient or potential injury to the surgeon.
The surgeon should be seated to allow the patient to be at a level visible to the anesthesiologist and the nursing staff. The hysteroscope should be at the level of the surgeon's abdomen; any higher and the surgeon's shoulders will become fatigued, and if positioned lower the instrument is hard to maneuver and more likely to become contaminated.
Prophylactic antibiotics are not indicated unless the patient has a history of tubal occlusion due to pelvic inflammatory disease or has significant valvular disease. Attempts to reduce blood loss and fluid deficits have been reported (and ultimately tried by this author). Using cold distention media (5 degrees Celsius) causes vasoconstriction and reduced blood loss and distention fluid deficits; however, the patient's core body temperature significantly decreases, which may interfere with the anesthesia process. Vasopressin in dilute solution (1%) can be injected paracervically to help constrict the cervical and lower uterine branches of the uterine artery and its collaterals, reducing blood loss and fluid deficits. Some studies also suggest that vasopressin may help dilate the cervix.
The cervix is dilated manually with metal dilators to the same diameter as the outer diameter of the outer sheath of the hysteroscope set-up. A single-tooth tenaculum is placed on the anterior lip of the cervix while dilating to help straighten the cervix and uterus. Care must be taken to avoid creating a false cervical passage that could make it difficult to continue with the surgery. If the surgeon is unsure of the path of the cervical canal, lacrimal duct probes or flexible uterine sounds should be used to determine the correct angle. Some recent reports suggest that the use of vasopressin (1%) paracervically helps dilate the cervix, which may facilitate dilation. Also, preoperative misoprostol has been used to assist in cervical dilation prior to hysteroscopy.
Once the cervix is dilated, the hysteroscope is inserted under direct visualization to limit the risk of uterine perforation. The tenaculum on the cervix is left in place to help in manipulating the uterus, and the vaginal speculum is removed to allow greater maneuverability of the hysteroscope. If the cervix was dilated too much and fluid is leaking extensively, a purse-string suture around the cervix using 0-Vicryl can be used to limit this. The suture should be removed at the end of the case.
Depending on the goal of the surgery (eg, fibroids, septum, adhesions), each case should be individualized with regard to the width of the hysteroscope, the type of media, the use of cautery, and the type of anesthesia.
Techniques
Typically, the cervix must be dilated to 7-9 mm depending on the resectoscope used. Preferably, an Iglesias grip mechanism on the resectoscope is used since it maintains the electrode within the shaft at rest. A 12-degree scope is suggested since it provides a panoramic view of the uterine cavity. A coagulation mode of 50-100 watts is used.
A roller barrel provides more uniform contact with the endometrium than the rollerball, yet it may not adequately ablate the cornua and fundus. A 2-mm rollerball is more effective than a 4-mm ball because it has more current density for a given power level. The ball or barrel is extended and allowed to passively return toward the sheath at 1.0-1.5 mm/second. Clinically, the proper amount of power is being used if a crater forms that is 25% of the volume of the electrode and the crater borders are carbonized. Occasionally, the rollerball or barrel may become coated with tissue and have to be removed and cleaned with a sterile gauze. If the endometrium is not thinned, resection may be preferred (see below).
The uterine cornua and tubal angles are ablated first because of their difficulty. Starting at 9-o'clock position, the lateral and anterior walls are ablated next since blood, debris, and bubbles will rise, making attempts in these areas more difficult later. The posterior wall then is ablated, continuing in a clockwise fashion. Do not continue to ablate over areas that have already been done due to the risk of uterine perforation.
Similar to the rollerball technique, the cervix is dilated to 7 or 9 mm, depending on the size of resectoscope. A blended current is preferred at 70-100 watts. A 5- or 7-mm loop electrode is used and extended. The electrode is allowed to return passively at 1.0-1.5 mm/second.
When performing an ablation, do not resect the same place twice. The tubal ostia angles are difficult to ablate with the loop electrode, so a small rollerball is preferable. Also, the corpus and isthmus may be quite thin, so a rollerball is preferable in this area as well. The correct wattage is being used if the loop easily penetrates the tissue without "tearing" it. The strips of resected tissue (endometrium or fibroid) require removal intermittently with polyp forceps. Typically, they will follow the flow of distention media as the hysteroscope is removed and lodge themselves at the internal os. Care must be taken when resecting a fibroid to limit the resection just to the fibroid and not the adjoining endometrial tissue, especially in women desiring to conceive. All tissue is sent to pathology for histologic evaluation.
Three methods are used in performing this procedure. A 12-degree scope is preferred with this procedure, as well.
A small 5- or 7-mm hysteroscope can be used with normal saline distention media. A 30-degree scope is preferable in order to see the tubal ostia clearly. The ability to introduce small surgical instruments through an operating channel is optimal. Office procedures can be done with 2.5- to 3-mm flexible or rigid hysteroscopes that are attached to normal saline in a bag or a 30-cc syringe. Some of the newer models have a small operating channel through which a thin-wired biopsy forceps can be placed. This is enough to sample suspicious areas or to remove small polyps.
A 5- to 7-mm hysteroscope is used with a 30-degree scope. The occluded tubal ostia is cannulated approximately 1-2 cm with a flexible tubal catheter, and indigo carmine is injected through the cannula and observed for its spill through the fimbriated end by the surgical assistant performing a laparoscopy. If no patency is documented, the assistant straightens the fallopian tube as the hysteroscopic surgeon slides a guide wire with a soft, flexible tip through the initial catheter and into the isthmic area of the fallopian tube. The wire then is withdrawn and patency is evaluated again.
Using a 5- to 7-mm hysteroscope and a 12-degree scope, the IUD is grasped with a toothed grasper. The IUD is pulled toward the hysteroscope sheath. It will be impossible to pull the IUD through the operating channel of the hysteroscope. Instead, the grasper is held closed and both hysteroscope and IUD are pulled out together.
Postoperative details: Patients typically will complain of cramping after the procedure. A single dose of Toradol will reduce postoperative discomfort. Opioid derivatives can be added, if needed, for more severe pain. There may be some peritoneal discomfort if a significant amount of the distention media has entered the abdominal cavity by way of the fallopian tubes. This generally will subside within 24 hours.
Most patients can go home within 1-2 hours, requiring nonsteroidal anti-inflammatory drugs (NSAIDs) for 24-48 hours. Patients may have some light to heavy spotting for a few days to a couple of weeks, depending on the procedure performed. If a fibroid resection is done, it is important to tell the patient that small pieces of tissue may be passed, which may cause cramping.
If extensive adhesions or fibroids were removed, this raises the possibility of adhesion formation within the uterine cavity. Many surgeons advocate the use of high-dose estrogen to encourage endometrial growth over any denuded areas. Typically, conjugated estrogen (2.5-5 mg daily orestradiol 2 mg twice daily for 25 days, followed by 5 days of progesterone) will suffice. To prevent the juxtaposition of the inner uterine walls during the initial phase of the healing process, an intrauterine catheter is recommended.
Many types have been used, including the Malecot and Foley catheters. The author prefers a pediatric Foley catheter with the balloon filled with 15- to 20-cc sterile water since it has the added benefit of tamponade to any areas that may be bleeding. The exterior end of the catheter is capped and the patient is placed on doxycycline 100 mg twice daily until it is removed 7 days later. The patient is instructed on how to remove the catheter (cut the catheter with scissors and just pull it out).
Follow-up care: Follow-up in 2-4 weeks is recommended to evaluate the patient and probe the cervix (in cases where ablation was performed) to break up any scar tissue that may have developed near the internal os. For a simple diagnostic hysteroscopy, no postoperative visit usually is necessary.
After resection of fibroids, polyps, or transection of a septum, a sonohysterogram should be done to confirm a normal uterine cavity. If adhesions were removed, a diagnostic hysteroscopy in the office or operating room likely is more sensitive.
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COMPLICATIONS |
An accepted rate for all complications during operative hysteroscopy is 3.8%.
Mechanical complications
Perforation and cervical trauma are 2 of the most common complications of hysteroscopy, with uterine perforation approximately 0.7-0.8% (Jansen, 2000). Dilation of the cervix can be challenging, especially in cases of a stenotic os, severe uterine anteflexion or retroflexion, lower uterine segment myomas, or synechiae (Loffer, 1995). It is at this point in the surgery that most cervical trauma and uterine perforations occur.
A single-toothed tenaculum used on the cervix to aid in dilation can itself cause lacerations of the cervix and extensive bleeding. Some authors suggest using a less trauma-producing instrument to grasp the cervix during dilation such as a double-toothed tenaculum or a ringed forceps (Cooper, [early], 2000; Loffer, 1995). Laminaria placed prior to surgery can aid in dilating the cervical canal, and investigators are evaluating other cervical ripening agents preoperatively (Cooper, [early], 2000). Ultrasound guidance during dilation can be helpful to aid in direction of dilation. An exam under anesthesia to confirm uterine position can be helpful, as well.
The hysteroscope should be introduced into the uterine cavity under direct visualization (ACOG, 1994; Schenk, 1999). An angled scope also can be useful in introduction to allow for accommodation to the flexion of the uterus (Serden, 2000). The small-diameter hysteroscopes and those that are flexible can avoid the need for much dilation at all.
Uterine perforations also can occur during operative maneuvers. A small midline or fundal injury with a blunt instrument usually does not have significant sequelae if bleeding is minimal, but larger rents or those caused by sharp or electrosurgical instruments may indicate diagnostic laparoscopy for complete evaluation for bleeding or visceral injury. Lateral perforations run the risk of injury to vessels and should be further inspected by diagnostic laparoscopy. In any case where injury to bowel or bladder by electrical or laser energy is suspected, laparoscopy or laparotomy for complete evaluation is required. The risk of peritonitis, sepsis, and death are associated more often with thermal injuries to viscera that go unrecognized and thus untreated. It is worth noting that some of these thermal visceral injuries occur without apparent perforation of the uterus. For procedures using electrical or laser energy, the surgical tip should be kept in direct view to avoid the risk of thermal injury.
Media-related complications
There is a minimal risk of absorption under normal operative conditions. The risk of intravasation includes prolonged operative procedures, the use of large volumes of low-viscosity media, or myometrial trauma from resection, which results in open uterine venous channels or unidentified perforation (Jansen, 2000). The risk of intravasation also can occur when the intrauterine pressure is greater than that of the patient𠏋 mean arterial pressure (Morrison, 1999).
The risk of gas embolism is the primary complication associated with the use of CO2 as the distention medium. Because of its solubility in plasma, CO2 has a wide margin of safety. If gas embolism should occur, there can be devastating results, with circulatory collapse. A few maneuvers can be applied to prevent a gas embolus including avoiding the Trendelenburg position, minimizing cervical trauma, keeping the cervical os occluded, and communicating with the anesthesiologist, as well as maintaining intrauterine pressures below 100 mm Hg and flow rates below 100 mL/min (Morrison, 1999).
When an embolus is suspected by a change in a patient𠏋 vital signs (hypotension, tachycardia, tachypnea, desaturation, and decrease in the end-tidal CO2), the hysteroscope should be removed, the patient positioned on the left side, and intravenous bolus of normal saline delivered as a first-line treatment (Cooper, [early], 2000). An attempt to percutaneously aspirate an embolus is reported in the literature (Cooper, [early], 2000). Further evaluation with an echocardiogram and possible cardiopulmonary resuscitation may be indicated.
Fluid overload is rare with electrolyte-containing fluids. When excessive intravasation occurs, an isotonic fluid overload occurs, which is relatively easy to treat. However, these fluids cannot be used in operative procedures requiring electrosurgical instruments, so they primarily are used in the setting of diagnostic hysteroscopy, although this is changing rapidly as more equipment is being developed that allows for surgical procedures to be performed with isotonic solutions.
On the other hand, nonelectrolyte media, which are nonconductive, can be used for electrosurgical procedures but have a more serious adverse effect profile. When large quantities of these solutions are absorbed, subsequent hyponatremic hypervolemia, hypotension, pulmonary edema, cerebral edema, and cardiovascular collapse can occur. Nonelectrolyte solutions should be monitored closely in long cases requiring large volumes of media. For every liter of hypotonic media absorbed, the patient𠏋 serum sodium will decrease by 10 mEq/L. If the patient𠏋 sodium is less than 120 mEq/L, then she is at increased risk of these complications. Absorption of more than 1000 mL of medium is associated with significant risks, primarily of dilutional hyponatremia and its sequelae and may require diuretics or sodium replacement initially for treatment.
Hyponatremia can occur rapidly, resulting in generalized cerebral edema, seizures, and even death. It generally is accepted that if a greater than 1500-mL deficit or serum sodium of less than 125 mEq/L is noted, the procedure should be terminated. Some suggest that of the choices of nonelectrolyte media, 5% mannitol has the safest side effect profile because it has been found to maintain a patient𠏋 osmolality despite hyponatremia, improving neurologic outcomes (Cooper, [early], 2000).
Along with hyponatremia, complications of fluid overload include pulmonary edema and coagulation defects. Severe hyponatremia predisposes to cerebral edema and possible herniation of the cerebral hemispheres through the tentorium, followed by dislocation of the brain stem through the foramen magnum. If the patient is young and healthy and the sodium is borderline low, fluid restriction and close observation is adequate as the patient diureses. Sodium levels every 30 minutes while the patient is in the recovery room is recommended. If the patient's sodium is less than 125 mOsm, forced diuresis with Lasix 40 mg IV, fluid restriction, and administration of 3% sodium chloride at a rate to correct hyponatremia by 1.5-2.0 mOsm/L/h is required. Do not correct to more than 135 mOsm to limit any cerebral effects.
Dextran 70 can cause significant overload in long surgical cases. This type of overload does not respond to diuretic treatment because dextran 70 is poorly excreted by kidney. Therefore, plasmapheresis may be required (Cooper, [early], 2000; Borten, 1983). Pulmonary edema and diffuse intravascular coagulation (DIC) are adverse effects commonly associated with dextran 70. The mechanism is suspected to be due to fluid overload or the toxic effect of dextran 70 on pulmonary capillaries and its probable anticoagulant effects (Cooper, [early], 2000; Loffer, 1995; Jedeikin, 1990).
Very close monitoring of input and output are imperative because a greater than a 500-mL deficit can cause significant sequelae. Anaphylaxis is another complication of dextran 70, with a frequency of 1 per 1500 to 1 per 300,000 patients (Cooper, [early], 2000; Borten, 1983; Jedeikin, 1990). Treatment of anaphylaxis includes initiation of diphenhydramine, epinephrine, steroids, and possible fluid and ventilatory support.
Bleeding
Bleeding during or after surgery is the second most common complication of hysteroscopy (0.25% of all cases), with myomectomy as the procedure with the highest complication rate (2-3%) (Cooper, [early], 2000). Some studies suggest improvements in blood loss and pre-procedure hematocrits when patients are pretreated with GnRH agonists or oral contraceptive pills (Cooper, [early], 2000). Although, distention of the uterus with media can tamponade bleeding, the coagulating effects of some operative instruments also can aid in the control of bleeding during surgery.
If bleeding persists postoperatively, a 30-mL Foley catheter balloon filled with 15-30 mL of fluid can be inserted into the cavity. This can be removed easily 24 hours later. Vasopressin and misoprostol are alternate medications that can help with vasoconstriction and uterine contractions. As a last resort, uterine artery embolization or hysterectomy are options for definitive management.
Infection
Infection is an uncommon complication of hysteroscopy. Even with dextran 70, which is a polymerized sucrose, infection in a patient who is preoperatively screened is rare. If a patient is found to have an infection preoperatively or a significant history of pelvic inflammatory disease, treatment prior to surgery is recommended, but prophylactic antibiotics have not been shown to reduce infection postoperatively (Cooper, [early], 2000; Loffer, 1995; Gimpelson, 2000). Antibiotics should be used for indicated prophylaxis for subacute bacterial endocarditis. Cystitis and endometritis are the more common infections associated with hysteroscopic procedures, and these should be treated in a standard fashion (Cooper, [early], 2000).
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OUTCOME AND PROGNOSIS |
Outcomes for each type of procedure are discussed in prior sections. Obviously, attempt at hysteroscopic evaluation or treatment is meant to overcome the traditional problems associated with more invasive procedures done in the past with longer hospital stays, increased morbidity, and increased costs.
In addition to surgical success rates, long-term patient satisfaction, sexual function, and overall quality of life are important considerations. For example, when comparing endometrial ablation to hysterectomy, it not only is more cost-effective, but patients report 80-85% satisfaction sexually, functionally, and psychologically.
One area of uncertainty pertains to hysteroscopic resection of large submucosal fibroids, especially those with extensive myometrial involvement. When fibroids are removed through a laparotomy and a large defect is repaired, the patient is counseled not to labor when she is pregnant. Intuitively, patients who have large defects after a hysteroscopic procedure should be counseled the same.
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FUTURE AND CONTROVERSIES |
The thermal catheters are being used more frequently for endometrial ablation (Neuwirth, 1994).
Thermal balloon used for menorrhagia has effects equal to hysteroscopic ablation (Singer, 1994). The thermal balloon is injected with 5% dextrose in water under controlled pressure and temperature at 92 degrees Celsius after it has been inserted into the uterus and conformed to its shape (Neuwirth, 1994). It then thermally ablates the endometrium to a variable level of 3.3-10 mm; generally, thermal destruction occurs to a 3- to 4-mm depth including the basal layer (Schenk, 1999). The whole procedure takes 8 minutes to complete. Success rates are comparable to traditional hysteroscopic ablation, but amenorrhea rates are only 15% (compared to 40% for the hysteroscopic approach).
Thermal ablation allows for a more predictable heat source with a low risk of perforation (Neuwirth, 1994). Perforation occurs only with aggressive placement (Neuwirth, 1994). Rupture of the balloon can cause thermal injury to the cervix or vagina (Neuwirth, 1994). The skill level required to use the thermal balloon is equivalent to that for the placement of an IUD (Neuwirth, 1994). A preoperative evaluation including ruling out malignancy is required (Neuwirth, 1994).
Another method that recently received FDA approval is a technique that instills saline heated to 90 degrees Celcius directly onto the endometrium at low intrauterine pressures of 50 mmHg. This low pressure prevents the saline from escaping through the fallopian tubes, which will open when the intrauterine pressure exceeds 70 mmHg. Success rates are once again similar to the hysteroscopic approach; However, the reported amenorrhea rate is higher than the thermal balloon approach and nearly similar to the 40% achieved with the hysteroscopic ablation.
As sonohysterography becomes more commonplace, 3-dimensional ultrasonography software improves, and physicians are forced to apply more cost-effective procedures, it seems that this technology will be utilized to perform certain operative procedures that traditionally were done with hysteroscopy.
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BIBLIOGRAPHY |