Cervical stenosis and difficult uterine and vaginal anatomy pose a challenge for the gynecologist who needs access to the cervix and uterus to evaluate pathology. Overcoming this hurdle requires a careful, considered approach to avoid the complications of dilation, such as laceration, creation of a false passage, uterine perforation, and failed procedures. Care and consideration also ensure a successful and comfortable procedure; save the patient a great deal of time and the higher expense of the operating room (OR); and avert the need for general anesthesia.
In this first Update on Minimally Invasive Surgery, I will:
- describe the continuing shift from the OR to office for many gynecologic procedures
- review recent data on cervical softening
- outline the components of mechanical dilation
- offer tips on pain relief.
Need for cervical access should not prohibit office-based procedures
Cervical access is critical to increase the percentage of procedures performed in the office setting. The office has long been the ideal environment for minor procedures such as endometrial biopsy, dilation and curettage, diagnostic hysteroscopy, hysterosonography, and insertion of an intrauterine device—but difficulty traversing the cervix has relegated many of these procedures to the OR.
Minor procedures such as tubal sterilization and endometrial ablation have begun to move from the outpatient environment into the office as well, upping the number of office procedures that require safe access to the endometrial cavity.
For example, hysteroscopic tubal occlusion (Essure) is performed transcervically, thereby eliminating all incisions and the need for general anesthesia. Approximately 50% of all Essure sterilization procedures performed in the United States today are done in an office, and that percentage is expected to rise to 60% in 2009.1
The smallest operative hysteroscopes that allow for placement of Essure coils have an outer-sheath diameter between 5 and 6 mm. Even with such small diameters, cervical dilation is sometimes needed.
Endometrial ablation offers women who have menorrhagia a minimally invasive option for treatment. Several FDA-approved devices are used safely in the office.2-5 Cervical dilation requirements for these devices range from 5 to 7.8 mm, making cervical access paramount (TABLE).
A number of measures, such as cervical softening and mechanical dilation, can ease dilation in an office setting so that a stenotic cervix no longer requires an OR for the procedure to be completed. Successful in-office cervical dilation also greatly reduces cost.
TABLE
Size of the instrument varies across endometrial ablation systems
| Instrument | Diameter | Instrument | Diameter |
|---|---|---|---|
| ThermaChoice (uterine balloon therapy) | 5 mm | NovaSure | 7.2 mm |
| Her Option (cryoablation therapy) | 5 mm | Hydro ThermAblator | 7.8 mm |
New data back efficacy of vaginal misoprostol for cervical softening
da Costa AR, Pinto-Neto AM, Amorim M, Paiva LH, Scavuzzi A, Schettini J. Use of misoprostol prior to hysteroscopy in postmenopausal women: a randomized, placebo-controlled clinical trial. J Minim Invasive Gynecol. 2008;15:67–73.
Waddell G, Desindes S, Takser L, Bequchemin M, Bessett P. Cervical ripening using vaginal misoprostol before hysteroscopy: a double-blind randomized trial. J Minim Invasive Gynecol. 2008;15:739–744.
Uckuyu A, Ozcimen E, Sevinc FC, Zeyneloglu HB. Efficacy of vaginal misoprostol before hysteroscopy for cervical priming in patients who have undergone cesarean section and no vaginal deliveries. J Minim Invasive Gynecol. 2008;15:472–475.
Valente EP, Amorim MM, da Costa AR, de Miranda VD. Vaginal misoprostol prior to diagnostic hysteroscopy in patients of reproductive age: a randomized clinical trial. J Minim Invasive Gynecol. 2008;15:452–458.
A synthetic analog of prostaglandin E1, misoprostol is thought to act on the extracellular matrix of the cervix, leading to water absorption, neutrophil collagenase release, and cervical softening. Smooth muscle is activated by the drug, especially in the uterus.
Pharmacokinetic studies suggest that the oral route of misoprostol has the shortest interval to peak serum concentration (within 30 minutes of ingestion), but that concentration declines within 1 hour. The vaginal route, on the other hand, has fewer side effects, with longer duration and approximately three times the bioavailability.6,7 Peak values are equal to those of orally administered misoprostol. They are attained at 60 minutes, then decline slowly, reaching 50% of peak values by 240 minutes. Serum concentration remains elevated, improving efficacy.
I recommend an interval of 4 to 12 hours between vaginal placement and the start of the procedure.