When outcomes of cerclage are evaluated, women with similar clinical presentations are ideally compared. For example, in the study of elective cerclage by Owen and associates (2009), approximately a third of women delivered before 35 weeks, and complications were few. By contrast, in a 10-year review of 75 women undergoing rescue cerclage procedures, Chasen and Silverman (1998) reported that only half were delivered after 36 weeks. Importantly, only 44 percent of those with bulging membranes at the time of cerclage reached 28 weeks. Terkildsen and associates (2003) had similar experiences. Caruso and coworkers (2000) described rescue cerclage done in 23 women with a dilated cervix and protruding membranes from 17 to 27 weeks' gestation. There were 11 liveborn neonates, and these researchers concluded that success was unpredictable. Our experiences at Parkland Hospital are that rescue cerclages have a high failure rate, and women are counseled accordingly.
If the clinical indication for cerclage is questionable, a woman may instead be observed. Most undergo cervical examinations weekly or every 2 weeks to assess efacement and dilatation. Unfortunately, rapid efacement and dilation can develop despite such precautions (Witter, 1984).
Of the two vaginal cerclage operations, most use the simpler procedure developed by McDonald (1963) and shown in
Figure 1i8-2. The more
FIGURE 18-2 McDonald cerclage procedure for incompetent cervix. A. Start of the cerclage procedure with a no. 2 monofilament suture being placed in the body of the cervix very near the level of the internal os. B. Continuation of suture placement in the body of the cervix so as to encircle the os. C. Encirclement completed. D. The suture is tightened around the cervical canal sufficiently to reduce the diameter of the canal to 5 to 10 mm, and then the suture is tied. The efect of the suture placement on the cervical canal is apparent. A second suture placed somewhat higher may be of value if the first is not in close proximity to the internal os.
complicated operation is a modification of the procedure described by Shirodkar (1955) and shown in Figure 18-3. When either technique is performed prophylactically, women with a classic history of cervical incompetence have excellent outcomes (Caspi, 1990; Kuhn, 1977). For either vaginal or abdominal cerclage, there is insuicient evidence to recommend perioperative antibiotic prophylaxis (American College of Obstetricians and Gynecologist, 2016b,i). Thomason and coworkers (1982) found that perioperative tocolytics failed to arrest most labor. Regional analgesia is suitable and preferred. Ater this, the woman is placed in standard dorsal lithotomy position. he vagina and perineum are surgically prepared, and the bladder is drained. Some operators do not use potentially irritating antiseptic solution on the exposed amnionic membranes and instead use warm saline (Pelosi, 1990). Although steps are described subsequently, a thorough and illustrated review of cerclage technique is provided by Hawkins (2017). For suturing, options include a no. 1 or 2 nylon or polypropylene monoilament suture or 5-mm Mersilene tape. During placement, the suture is placed as high as possible and into the dense cervical stroma. Two cerclage sutures do not appear more efective than one (Giraldo-Isaza, 2013).