Diagnostic Dilation and Curettage

Background

Diagnostic dilation and curettage was originally intended to detect intrauterine endometrial abnormalities and assist in the management of abnormal bleeding. Newer techniques are available to assess the uterine cavity and endometrial findings.[1, 2] However, dilation and curettage still has a role in centers where advanced technology is not available or when other diagnostic modalities are unsuccessful.

Traditionally, dilation and curettage has been performed in a blind fashion. The procedure can be performed under ultrasound guidance or in conjunction with visualization of the uterine cavity by a hysteroscope. A study by Cohen et al found that the use of ultrasound guidance during dilation and curettage for first-trimester missed abortion was not associated with a reduced rate of complications, compared with a blind approach.[3]

Indications

Diagnostic dilation and curettage is typically employed to assess endometrial histology. Fractional dilation and curettage also includes assessment of the endocervix and biopsy of the ectocervix and transformation zone.

Indications for a diagnostic dilation and curettage include the following:

• Abnormal uterine bleeding: irregular bleeding, menorrhagia, suspected malignant or premalignant condition

• Retained material in the endometrial cavity

• Evaluation of intracavitary findings from imaging procedures (abnormal endometrial appearance due to suspected polyps or fibroids)

• Evaluation and removal of retained fluid from the endometrial cavity (hematometra, pyometra) in conjunction with evaluating the endometrial cavity and relieving cervical stenosis

• Office endometrial biopsy insufficient for diagnosis or failed due to cervical stenosis

• Endometrial sampling in conjunction with other procedures (eg, hysteroscopy, laparoscopy)

The evaluation of the uterine cavity by dilation and curettage may be helpful when an office technique, such as ultrasound, is unable to fully elucidate the endometrium due to shadowing from leiomyomata, a pelvic mass, or loops of bowel.

Several studies have evaluated the effectiveness of obtaining endometrial tissue by endometrial sampling versus D&C. One study compared aspiration biopsy (Pipelle) with D&C. The D&C procedure was performed without hysteroscopy. This sample of 673 women underwent hysterectomy following the endometrial sampling or curettage. The concordance of results was 67% between endometrial biopsy and hysterectomy versus 70% between D&C without hysteroscopy and hysterectomy. The negative predictive value was 98% for detection of malignancy. In their conclusions, the authors recommended a presampling evaluation of the endometrium by a technique such as transvaginal ultrasound.[4]

Another study of 366 women evaluated histopathologic findings obtained by hysteroscopically directed biopsies, versus pathology results of tissue obtained at D&C. Concordance of results for the 2 procedures was 88.8%. In their conclusions, the authors stated that although hysteroscopy with directed biopsy was adequate for obtaining diagnosis from focal lesions, it may not be sufficient for diagnosis of all pathologic findings in the endometrium, including hyperplasia. They recommended global endometrial sampling, such as by D&C, be included for more thorough diagnosis.[5]

Dilation and curettage may also be a therapeutic procedure. Examples of this use include the following:

• Removal of retained products of conception (eg, incomplete abortion, missed abortion, septic abortion, induced pregnancy termination)

• Suction procedures for management of uterine hemorrhage

• Treatment and evaluation of gestational trophoblastic disease

• Hemorrhage unresponsive to hormone therapy[1]

• In conjunction with endometrial ablation for histologic evaluation of the endometrium

Contraindications

There are few contraindications to gentle office dilation and curettage, but a more vigorous examination may require an operative suite with regional or general anesthesia. Paracervical block or intravenous sedation with an anesthesia team standing by for assistance may also be an option. Intolerance to office examinations or procedures may determine the setting for the procedure. A study by Carlson et al found that patients who had dilation and curettage performed under general anesthesia experienced significantly greater estimated blood loss compared with patients who underwent the procedure under deep sedation.[6]

Absolute contraindications to dilation and curettage include the following:

• Viable desired intrauterine pregnancy

• Inability to visualize the cervical os

• Obstructed vagina

Relative contraindications to dilation and curettage include the following:

• Severe cervical stenosis

• Cervical/uterine anomalies

• Prior endometrial ablation

• Bleeding disorder

• Acute pelvic infection (except to remove infected endometrial contents)

• Obstructing cervical lesion

These contraindications may be surmounted in some cases. For example, magnetic resonance imaging may define the anatomy of the cervical or uterine anomaly, allowing safe exploration of the endocervix and endometrium.

Complications

Complications can occur at the time of diagnostic dilation and curettage. Careful performance of the procedure should minimize these events. Possible complications include the following:

• Bleeding or hemorrhage

• Cervical laceration

• Uterine perforation

• Postprocedural infection

• Postprocedural intrauterine synechiae (adhesions)

• Anesthetic complications

Complications, particularly uterine perforation, may be increased in a patient with a recent pregnancy or gestational trophoblastic disease, prior endometrial ablation, distorted anatomy, cervical stenosis, or current uterine infection.

Cervical Injury

Laceration of the cervix primarily occurs during traction, with a counterforce applied during dilation. It seems to occur most frequently with use of a single-tooth tenaculum, especially when it is placed vertically on the lip of the cervix. A Bierer multi-toothed tenaculum penetrates less deeply into the cervical tissue and transfers force over a greater area, potentially decreasing the risk of laceration.

Lacerations are generally managed with an interrupted or running interlocking dissolvable suture. The same technique would be applied for a laceration of the posterior cervical lip.

Placement of a tenaculum is not recommended at the lateral aspect of the cervix because of the location of the cervical branches of the uterine artery.

The risk of laceration is reduced by reducing force at dilation, using more tapered Pratt dilators or osmotic preparation before the procedure with laminaria or prostaglandin.

Uterine Perforation

Uterine perforation is one of the more common complications of dilation and curettage. Risks are increased when dealing with a pregnant or recently postpartum uterus (5.1%) and are less frequent at the time of a dilation and curettage remote from pregnancy (0.3% for premenopausal women and 2.6% for postmenopausal women).[7, 8, 9]

The instruments most commonly associated with uterine perforation are the uterine sound or dilators. If perforation is known to have occurred with a blunt instrument, observation of vital and peritoneal signs for several hours is all that is needed. If suspicion that a sharp instrument, such as a curette, has perforated the uterus or if the fat has been retrieved by curettage, then intraabdominal injury must be excluded by laparoscopy. Active bleeding may necessitate a laparotomy.

Infection

Infection related to diagnostic dilation and curettage is rare and is most likely when cervicitis is present at the time of the procedure. One study of infections related to dilation and curettage documented a 5% incidence of bacteremia following dilation and curettage with a very rare incidence of septicemia.

Prophylactic antibiotics are not recommended for any dilation and curettage, including for those women who generally require subacute bacterial endocarditis prophylaxis.

Intrauterine Adhesions

Curettage after delivery or abortion may result in endometrial injury and subsequent development of intrauterine adhesions, termed Asherman syndrome. The development of uterine synechiae may also be associated with prior endometrial ablation procedures. Intrauterine adhesions may make future diagnostic curettage more difficult and increase the risk of uterine perforation. Previous procedures such as endometrial ablation may also increase the risk of cervical stenosis.

A study by Hooker et al reported that intrauterine application of auto-crosslinked hyaluronic acid gel after D&C for miscarriage in women with at least one previous D&C may reduce the incidence and severity of intrauterine adhesions; however, it does not eliminate the process of adhesion formation completely. Further studies are needed to evaluate these results.[10]

Trophoblastic Embolization

Embolization of trophoblastic tissue in the systemic circulation is a very rare complication of dilation and curettage for removal of gestational trophoblastic disease. This event has been associated with thyroid storm, cardiovascular collapse, and death. A diagnostic dilation and curettage in patients for whom gestational trophoblastic neoplasia is suspected should be performed in an operating room with anesthesia.

Equipment

A Graves speculum may be used to visualize the cervix. Alternatively, a weighted speculum with one or more vaginal retractors in the anterior and lateral vaginal fornices may be used. The latter arrangement or a Graves speculum with an open side may be preferred if hysteroscopy is also planned. See the images below.

Several types of cervical dilators are commonly used. A dilator has a tapered end. Common dilator types include the Pratt, Hegar, and Hank dilators. See the image below.

The Pratt dilator has the most gradual taper and ranges in size from 13 to 43 Fr. The tips of the Hegar and Hank dilators are more blunt and may therefore require greater force to dilate the cervix. This could increase the risk of cervical laceration or uterine perforation, particularly in a pregnant uterus or with an inelastic cervix.

Tissue is removed with a curette, as shown in the image below.

The introduction of a Randall polyps forceps, as shown in the image below, may assist removal of pedunculated structures such as polyps or myomas or remove portions of tissue loosened during the curettage. See the image below.

Patient Preparation

Anesthesia

Office procedures may require no formal preoperative preparation if a need for cervical dilation is absent or minimal and a small-caliber endometrial sampling device or suction device is employed.

Some providers suggest patients undergoing cervical or paracervical instillation of local anesthetic be instructed to have an empty stomach. Manipulation of the cervix and placement of the curette may induce a vasovagal response with secondary nausea and vomiting.

Patients may be instructed to abstain from oral intake of solid foods for 6–8 hours and oral intake of clear liquids for 2 or more hours, even in the office setting. A preoperative over-the-counter pain medication, such as a nonsteroidal anti-inflammatory medication, may be taken with a sip of water at home prior to the procedure to assist with comfort during and after the dilation and curettage.

Procedures involving conscious sedation or regional or general anesthesia should follow the American Society of Anesthesiology guidelines for abstaining from clear liquids and oral consumption prior to surgical procedures. The current recommendations are no solid food for 8 hours preprocedure and no clear liquids for 4 hours preprocedure.[11]

Positioning

The procedure is typically performed in the dorsal lithotomy position. Care should be taken to prevent pressure injuries and excess abduction of the hip joint. Patients with orthopedic limitations may need to be positioned before sedation or general anesthesia is employed.

Monitoring & Follow-up

Cramps and mild vaginal bleeding are the most common symptoms reported following a diagnostic dilation and curettage. The expectations of these symptoms should be explained to the patient prior to her discharge from the office or outpatient surgery unit. Over-the-counter medications are usually sufficient for pain management.

Heavy bleeding, fever, abdominal pain or distention, nausea and vomiting, or foul vaginal odor should prompt an evaluation to exclude infection, perforation, or retained tissue.

Worsening of preexisting comorbidities should also be assessed based on any postoperative symptoms that the patient experiences.

Approach Considerations

Prophylactic antibiotics are not necessary. In the presence of a septic abortion or known pelvic infection, a full course of broad-spectrum antibiotics should be completed.[12]

Preoperative tests are not required for the procedure itself, but may be for the anesthesia. Pregnancy should be excluded. The presence of medical comorbidities may dictate preoperative laboratory or imaging studies in some patients, such as those with unstable pulmonary or cardiac disease or severe chronic medical conditions.

The procedure may be performed in an office setting or operating suite based on the patient's clinical presentation, comfort, medical comorbidities, and the suspected diagnosis.

Adjunctive measures, such as intraoperative ultrasound or hysteroscopy preceding dilation and curettage, may allow safer more efficient evaluation of the endometrial cavity, even in patients with anatomic abnormality.

Examination

An examination under anesthesia is performed before beginning the dilation and curettage procedure. To adequately perform the examination, a large distended bladder may need to be emptied. Incomplete emptying of the bladder or reinstillation of sterile fluid via Foley catheter may be helpful if transabdominal ultrasound guidance is planned.

Careful determination of the uterine size and flexion (the relationship of the uterine fundus to the cervix) and version (the angle or relationship of the cervix to the uterine fundus) will reduce risk of perforation of the uterus. The adnexa should also be carefully examined and a rectovaginal examination may be employed if further assessment of the cul-de-sac or uterine sacral ligaments is pertinent.

Preparation and Visualization

An aseptic solution is applied to the vulva and vagina and appropriate sterile drapes are placed.

A Graves speculum may be used to visualize the cervix. Alternatively, a weighted speculum with one or more vaginal retractors in the anterior and lateral vaginal fornices may be used. The latter arrangement or a Graves speculum with an open side may be preferred if hysteroscopy is also planned.

Removal of the speculum and retractors after the hysteroscope is placed into the cervix and uterus increases mobility of the hysteroscope and may improve visualization of the endometrial cavity.

Traction

The cervix is usually grasped on the anterior lip. A single-tooth tenaculum is frequently used, but a double-tooth or Bierer tenaculum will penetrate less deeply into the cervical tissue and may reduce the risk of cervical laceration. Alternative grasping instruments include ring forceps or Allis clamp.

Alternatively, the posterior lip can be grasped if there is a cervical anatomic abnormality or a previous cervical laceration.

Traction on the cervix is critical while performing a dilation and curettage. Traction decreases the angle between the cervix and uterus up to 75 degrees, reducing the necessary force to dilate the cervix and the risk of perforation.

Endocervical Curettage

If an endocervical curettage specimen is necessary, it should be obtained before performing cervical dilation or endometrial sounding to decrease histologic contamination of this specimen. The most common instrument used for this sampling is a Kevorkian-Younge curette.

An alternate sampling method used in the office setting if a patient cannot tolerate a rigid curette may include a cervical brush[13] introduced into the endocervix through a sheath to prevent ectocervical or transformation zone contamination. A specimen obtained with this device should be sent for pathologic examination, not to cytology.[14, 15]

The endocervical sample should be obtained by working in a circumferential or four-quadrant fashion to provide a representative specimen of all areas.

Endometrial cancer is staged based on the hysterectomy specimen. Therefore, endocervical curettage is not required for this purpose. Endocervical curettage may be employed to evaluate the presence of cervical dysplasia. If it is performed in conjunction with a loop electrocautery excision or conization of the cervix, it should be obtained after the excisional specimen is removed.

Uterine Sounding

A uterine sound is placed while traction is applied with the tenaculum. This assists in obtaining information about the uterine size and the presence of remaining version and flexion. The sound is held lightly between the thumb and first finger and placed through the cervix and into the endometrium without force. The average length from external os to fundus is 8-9 cm.

If cervical stenosis is present, some dilation of the cervix may be required before the sound can be placed. Sounding of a pregnant uterus is not recommended because of the increased risk of perforating the soft myometrium. Transabdominal ultrasound guidance may assist sounding if altered anatomy is suspected or stenosis is present.

Cervical Dilation

Each dilator is grasped with the first finger and thumb, similar to the grasp used with the uterine sound. It is held at its midportion and inserted into the cervical os just past the internal cervical os. It should not be inserted to the uterus fundus since this may traumatize the endometrium and subsequent bleeding may limit visualization if a hysteroscope is to be used. Insertions to the fundus may increase the chance of uterine perforation.

Dilation should continue until the appropriate diameter of the instruments to be inserted has been achieved.

Cervical ripening agents, such as laminaria or misoprostol, may enhance the ease of dilation and decrease force required.[16, 17, 18]

Sharp Curettage

Curettage is performed in an organized fashion with each placement proceeding from the fundus to the internal cervical os. Tissue is removed with a curette through the external os and collected for pathologic examination.

The curettage is performed in a circumferential fashion, noting the "uterine cry" that develops when the endometrial cavity is clean. The uterine cry is a gritty feel with movement of the curette.

Special care is taken around the uterine cornua, where the myometrium is thinnest. Other cavity irregularities such as fibroids, a septum or polyps, or even prior scars from uterine incisions may be noted by tactile examination with curette. If a hysteroscope is used before curettage is performed, visualization may note the presence of specific areas for individual biopsy or special attention during the curettage. The sensation of abnormalities, such as submucous fibroids, may be detected tactilely with the use of a curette.

A classic study of the thoroughness of endometrial curettage performed in patients preparing for hysterectomy revealed that less than 25% of the uterine cavity was sampled in 16% of patients, less than 50% of the cavity was sampled in 60% of patients, and less than 75% of the cavity was curetted in 84% of patients.[19, 20] These statistics represent adequate sensitivity for the detection of malignant or premalignant conditions. This sensitivity may also be increased by preoperative imaging with directed biopsy or intraoperative hysteroscopy.

The introduction of a Randall polyps forceps may assist removal of pedunculated structures such as polyps or myomas or remove portions of tissue loosened during the curettage.

Suction Curettage

Suction curettage is infrequently used for diagnostic dilation and curettage. It may be indicated if the patient's bleeding is extremely heavy, a large amount of tissue is visualized at preoperative imaging, or gestational trophoblastic disease is suspected. A suction curette is substituted for the sharp curettage.

A cannula is inserted to the mid portion of the endometrial cavity. Suction is employed with a vacuum pressure of 50-60 mm Hg and the cannula is rotated 360 degrees. Evacuation of the uterus results in a decreased uterine size and the tactile sensation of the uterus gripping the cannula. The cannula may be removed and replaced at the uterine fundus. When tissue is no longer seen in the suction tubing, the cannula is removed and a sharp curettage performed. A circumferential evaluation of the endometrial cavity is performed and the curettage is complete when the uterine cry is noted.

In the operating room in the presence of gestational trophoblastic neoplasia, a large uterus with retained tissue or products of conception, or postdelivery bleeding, oxytocin or other agents that aid uterine contractility should be immediately available and employed as needed to decrease blood loss.

Future Developments

A future use of endometrial sampling is as a noninvasive method of obtaining mature natural killer cells and hematopoietic stem cells.[21]