Gynecologic Procedures: Imaging Studies and Surgery

Imaging Studies in Gynecologic Practice

Ultrasonography is widely used for diagnostic purposes and even to guide therapeutic applications such as oocyte retrieval for in vitro fertilization (IVF). The ultrasonic probe emits high-frequency sound waves that provide an image of tissues when reflected back to the sound source (a probe). Ultrasound is safe for both pregnant and nonpregnant women and should be used to assist but not replace adequate physical examination and history-taking. Ultrasound may be two-, three-, or even four-dimensional when movement is detected in real time. Two-dimensional technology is the most common, with three-dimensional imaging and movement detection and interpretation reserved for special studies, such as fetal cardiac evaluation. The sound-generating probe may be placed on the abdominal wall (transabdominally) or into the vaginal canal (transvaginally). Transvaginal insertion is more commonly used for gynecologic evaluation.

Figure 31-1 illustrates the transvaginal placement of the probe against the uterine cervix. This placement allows for excellent visualization of both normal anatomy and abnormal pelvic masses (uterine and adnexal). The size of ovarian follicular cysts can be measured and followed over time to assist fertility evaluation and treatment as well as oocyte retrieval (see Chapter 34 ). When saline is infused through a catheter into the uterine cavity during transvaginal ultrasonography, a sonohysterogram may be visualized and recorded.

Computed axial tomography (CAT or CT) uses computer algorithms to form cross-sectional x-ray images of pelvic tissues. Contrast media may be used to enhance the images. CT scanning uses radiation and for this reason ultrasound or MRI may be preferred in pregnant patients.

MRI takes advantage of differing characteristics of body tissues when the tissues are exposed to magnetic field energy. By visually distinguishing between tissues such as fat and body fluids like blood and lymph, MRI is useful for the evaluation of uterine and ovarian structures. Uterine adenomyosis (see Chapter 25 ) and certain breast lesions may be detected using MRI.

Mammography uses radiation that penetrates compressed breast tissue to screen for breast cancer. There is both a false-positive and false-negative interpretation error associated with screening mammograms. Both MRI and ultrasound may be used to improve diagnostic accuracy (see Chapter 30 ).

Hysterosalpingography (HSG) employs fluoroscopy and radiopaque dyes injected transcervically to create an image of the uterine cavity and to verify fill and spill of dye out of the fallopian tubes (tubal patency). Uterine polyps and submucous uterine fibroids may be detected. Some studies show a statistically significant increase in the pregnancy rate after HSG, especially when oil-based media are used, suggesting therapeutic value. Figure 34-2 shows an HSG study.

Gynecologic Procedures

The gynecologic surgeon should have a high level of training during residency, followed by an ongoing commitment to retraining and retooling as effective procedures are added or substituted for outdated ones. Training methods now include computer-assisted simulations of procedures, providing for greater patient safety while the surgeon is learning and retraining. All facilities should have an active quality assessment program to continuously evaluate the safety and appropriateness of gynecologic care, including surgery.

Before any procedure or surgery begins, the most appropriate option (when more than one exists) for an individual patient must be selected, with optimal patient involvement in the decision-making process included as part of informed consent.

At least 80% of gynecologic surgical procedures are considered to be elective; that is, there are other alternative treatments to be considered. The appropriateness of performing these procedures should be evaluated by physician and patient on an individual basis ( Box 31-1 ). The trend toward minimal invasiveness in gynecologic surgery should not lead to minimal or questionable indications.

Credentialing, Privileging, and Ongoing Training

The rapid introduction of new technologies can present a challenge to the surgeon, who will need to keep up with the most advanced procedures, and to the institution, which is required to be certain that those who are granted surgical privileges have been properly trained and are currently qualified.

After a surgeon's credentials (diplomas, training certificates, and licenses) have been properly verified, a useful classification for the purpose of privileging stratifies procedures into the following levels:

• Level 1: procedures not requiring additional training after residency (e.g., dilation and curettage [D&C], cervical conization, adnexal excision, and abdominal or vaginal hysterectomy)

• Level 2: procedures requiring additional training (e.g., laparoscopic myomectomy)

• Level 3: procedures requiring advanced training and special skills generally acquired during subspecialty training (e.g., radical hysterectomy, tubal anastomosis, or oocyte harvesting)

As new procedures are incorporated into basic residency training, they can be reclassified.

Informed Consent and General Risks Associated with Procedures

The patient should be thoroughly counseled about surgical risks as part of the process of informed consent (see Chapter 1 ). In general, risks fall into three categories: risks of anesthesia, intraoperative risks, and postoperative complications. Risks of anesthesia depend on the type of anesthesia used (awake sedation, regional anesthesia, or inhalational agents). Regional anesthesia carries the risk of infection, postprocedural spinal headache, and failure, in which case an inhalational agent must be added to the regional anesthetic. Inhalational agents may be associated with the risks of aspiration pneumonia, allergic reaction to the agent, and damage to teeth or airways if intubation is necessary. Stroke, myocardial infarction, and death can result. The intraoperative risks include excessive bleeding and unintended damage to organs or tissues. Postoperative risks include infection, persistent bleeding, and thrombosis, all of which can lead to significant morbidity or even mortality. The specific risks of each procedure are described below.

Endometrial Sampling Procedures

One of the most common minor gynecologic surgical procedures is dilation of the cervix and curettage of the endometrium (D&C). Recent advances in office-based instrumentation for diagnosis (hysteroscopy, endometrial biopsy [ Figure 31-2 ], and ultrasonic evaluation of endometrial thickness) have resulted in an appropriate decrease in the use of D&C. However, if cancer of the cervix or endometrium is suspected, a thorough fractional curettage may be the best procedure to use to confirm its presence.

Cervical Procedures

Conization of the cervix is a procedure in which a cone-shaped portion of the cervix is removed for diagnostic or, occasionally, for therapeutic purposes. The section of the tissue surrounding the external os represents the base of the removed specimen. The apex is either close to the internal os ( Figure 31-3, A ) or close to the external os (see Figure 31-3, B ). Conization may also be performed in an office setting, using loop electrosurgical excision (see Figure 31-3, C ) or large loop excision of the transformation zone of the cervix. Loop excision should not be performed before identification of a cervical intraepithelial lesion that requires treatment by colposcopically directed punch biopsy. The technique and complications of cervical conization are also covered in Chapter 38 .

Colposcopy is the use of magnification to view and evaluate the cervix and to determine optimal sites for biopsy. A more detailed description of this procedure is provided in Chapter 38 .

The technique of cryoablation is commonly used to treat condylomas of the cervix, vagina, and vulva. These procedures almost always are office-based, and little if any anesthesia is required.

Laser instruments are sources of intense beams of light energy. The letters in the acronym laser stand for light amplification by the stimulated emission of radiation. When used in surgery, this radiant energy is converted inside the cell to thermal or acoustic energy, resulting in controlled vaporization or coagulation of tissue. Lasers come in longer wavelengths (carbon dioxide [CO ₂ ]) or shorter wavelengths (neodymium : yttrium-aluminum-garnet [Nd : YAG], potassium-titanyl-phosphate [KTP], and argon) that can be propagated along flexible optical fibers. This allows delivery of energy for cutting, vaporization, and coagulation to tissues in locations unreachable by a CO ₂ laser.

Because of the additional expense of laser equipment and the lack of evidence for improvements in outcome, the use of this technology has been decreasing in recent years. Nevertheless, laser technology has been applied to conization of the cervix, removal of leiomyomas (myomectomy), and destruction of the ectopic endometrial implants of endometriosis.