The Methodist Ambulatory Surgery and Medical Center in San Antonio is the nation's unofficial capital for minimally invasive GYN, at least according to the facility's director of operations, Michelle Rhunke, RN. "If there's a new device out there, we've tried it," she says. Many of those devices treat patients who present with menorrhagia, the prolonged and heavy menstrual bleeding that can be caused by submucosal fibroids growing in the muscle along the inner lining of the uterus.
Hysterectomy remains the only proven way to completely treat the condition but the procedure's complexity and risk of complications relegate it to the ORs of acute care hospitals. Endometrial ablation and tissue morcellation are more conservative approaches for managing menorrhagia and are ideally suited for the ambulatory setting. The potential risks during these minimally invasive treatments of submucosal fibroids are rare and far outweighed by the procedure's efficacy and benefit to the patient, says Ms. Rhunke. "There are no large abdominal scars and no gas blown into the abdomen," she says. "Patients wake with minor cramping and are ready to go home in a matter of hours instead of days."
Use of a saline sonohysterogram - pelvic ultrasound with saline injected into the uterus - is the easiest method to detect a submucosal fibroid, says James H. Liu, MD, the Arthur H. Bill professor and chair of the Case Western Reserve University's Department of Reproductive Biology in Cleveland and physician at the Department of Obstetrics and Gynecology at Cleveland's MacDonald Women's Hospital. He says small submucosal fibroids - generally less than 2cm in diameter - can be treated with endometrial ablation. The ablation devices are inserted into the uterine cavity through the cervix.
Dr. Liu notes that patients suited for endometrial ablation experience excessive menstrual bleeding that limits daily activities and have tried unsuccessfully to curb the bleeding with medications or a dilatation and curettage procedure. In a study published in the July 2004 issue of the journal OBG Management, Dr. Liu reports excessive uterine bleeding is "bleeding exceeding 80ml per menses or a menstrual flow longer than seven days."
Here's a quick review of endometrial ablation treatment options.
- Radiofrequency energy. This technique is performed with a handheld, disposable ablation wand that functions as a bipolar electrode, says Dr. Liu. A small sheath is inserted into the uterus before the wand expands into a fan-like array to contact the uterine walls. The flexible device conforms to the shape of the uterine cavity before ablating the endometrium with a 90-second blast of bipolar energy. A thermal energy feedback system shuts off the electrode when the endometrial lining of the uterus is removed. This procedure is technically easy to perform and the automatic shutoff feature makes it close to foolproof, says Stanley Filip, MD, chief of Duke Women's Health Associates and medical director of Duke South Obstetrics and Gynecological Clinics in Durham, N.C.
- Thermal fluid ablation. Surgeons first use a hysteroscope to view the uterus while free-flowing, room temperature saline is pumped into the uterine cavity. The saline solution is slowly heated to 90'C to ablate the endometrial lining. Following ablation, cooled saline solution is delivered into the uterine cavity. The free-flowing saline solution is not contained in a fixed shape and can conform to irregular uterine anatomy.
- Balloon therapy. As with the thermal fluid ablation technique, for this procedure the surgeon visualizes the uterus using a hysteroscope. The thermal fluid, in this case 5% dextrose solution and water, is delivered into the uterine cavity via a disposable silicone balloon connected to a thin catheter. After insertion, the balloon is inflated to a starting pressure of 160mmHg to 180mmHg and the solution within the balloon is heated to 87'C for 8 minutes to ablate the endometrial lining. Dr. Liu warns that this technique may not reach optimal outcomes in patients with irregular uterine cavities.
- Cryotherapy. Instead of heat, this technique employs sub-zero temperatures to destroy the uterine lining. A cryoprobe is inserted into the uterus and cooled to between -100'C and -120'C, which allows an ice ball to form on the probe's tip. The ice ball freezes and destroys endometrial tissue that it touches. While thermal procedures typically require general anesthesia, freezing procedures are less painful and can be performed using only local anesthesia, says Dr. Filip.
When you compare the treatment options, you'll find each end in similar outcomes with similar risks. Dr. Liu reports short-term complications include uterine perforation, low-grade endometritis, cervical stenosis, hematometra and pelvic infection. These problems are rare, he says, while cramping pain following ablation is more common. "We suspect that this is due to cytokine release from the necrotic tissue," he explains, adding that intraoperative or post-op intravenous keterolac is often an effective analgesia against cramping discomfort.
Dr. Liu notes endometrial ablation procedures may need to be prepped with a dilatation and curettage procedure to remove excess endometrium or the administration of danazol or leuprolide to reduce estrogen stimulation of the endometrium in the month prior to the procedure. His report notes patients undergoing thermal fluid ablation should be treated with a gonadotropin-releasing hormone (GnRH) agonist or suction curettage. The typical pre-op treatment for each technique - except the radiofrequency energy procedure, which requires no pre-op preparation - consists of hormonal treatment with GnRH agonists over two menstrual cycles and suction dilatation and curettage, says Dr. Liu.
If the submucosal fibroid is greater than 3cm, it is difficult to remove through the cervix unless the surgeon is quite skilled, says Dr. Liu. "In these cases, tissue morecellators are not used through the cervix because of insufficient visualization," he explains. "They are instead used when fibroids are removed via laparoscopy."
Fibroids are filled with very vascular tissue. When that vascular tissue is shaved during traditional hysteroscopy, the uterine cavity fills with blood particles that limit the surgeon's field of vision, increasing the potential for perforation of the uterine wall. The surgeon must remove the hysteroscope, suction the blood particles and replace the scope. That repeated maneuver increases the chance of puncturing the uterine wall.
The latest tissue morcellator devices pass through the hysteroscope. Surgeons visualize the uterus, locate a fibroid and place the morcellator against the lesion. Once activated, the morcellator twists into the fibroid, chews it up and simultaneously aspirates the debris. The surgical field remains clear and the scope remains in the uterine cavity for the duration of the case.
Those two factors make the procedure safer and quicker than traditional hysteroscopy. In fact, a study appearing in the January/February 2005 issue of the Journal of Minimally Invasive Gynecology reports the morcellation method reduces the average op time from just over 42 minutes to about 16 minutes.
Dr. Liu says the regenerative properties of endometrial tissue means anything short of a hysterectomy cannot be fully guaranteed to cure menorrhagia. Still, patients suffering from excessive menstrual bleeding are often in dire need of treatment. Without it they'd face a hysterectomy and an extended hospital stay, says Ms. Rhunke. These approaches to removing a potential cause of menorrhagia are not new to the outpatient arena but they are becoming more accepted as surgeons educate themselves - and patients - about their efficacy.