FIGURE 18-3 Modified Shirodkar cerclage for incompetent cervix. A. A transverse incision is made in the mucosa overlying the anterior cervix, and the bladder is pushed cephalad. B. A 5-mm Mersilene tape on a swaged-on or Mayo needle is passed anterior to posterior. C. The tape is a cerclage in place with labor contractions. T ransvaginally placed cerclages are typically removed even with cesarean delivery to avoid rare long-term foreign-body complications (Hawkins, 2014). With scheduled cesarean delivery, the cerclage may be removed at 37 weeks or deferred until the time of regional analgesia and delivery. Again, the risk of labor ensuing before delivery must be considered. During extraction, particularly with a Shirodkar cerclage or a cerclage using Mersilene tape, analgesia helps ensure patient comfort
B and adequate visualization.
At times, suture placed at the uterine isthmus can be used and left until completion of childbearing. Because of significantly greater risks of bleeding and complications during placement, this approach is reserved for selected instances of severe cervical anatomical defects or prior transvagi c nal cerclage failure.
Placement of a cervicoisthmic cerclage was originally described using laparotomy, but several reports additionally detail lapa then directed posterior to anterior on the other side of the cervix. Allis clamps are placed so as to bunch the cervical tissue. This diminishes the distance that the needle must travel submucosally cervicoisthmic cerclages. Steps are and aids tape placement. D. The tape is snugly tied anteriorly, after ensuring that all slack has been taken up. The cervical mucosa is then closed with continuous stitches of chromic suture. summarizedin Figure 18-4. Tulandi
Rescue cerclage with a thinned dilated cervix is more diicult and risks tissue tearing and membrane puncture. Replacement of the prolapsed amnionic sac back into the uterus will usually aid suturing (Locatelli, 1999). Options include steep Trendelenburg or filling the bladder with 600 mL of saline through an indwelling Foley catheter. However, these steps may carry the cervix cephalad and away from the operating field. Membrane reduction can also be achieved by pressure from a wide moist swab or by placing a Foley catheter through the cervix and inlating the 30-mL balloon to deflect the amnionie sac cephalad. The balloon is then deflated gradually as the cerclage suture is tightened around the catheter tubing, which is then removed. Simultaneous outward traction created by ring forceps placed on the cervical edges may be helpful. In some women with bulging membranes, transabdominal amnionic fluid aspiration to decompress the sac may be considered. If this is done, bacterial cultures of the luid should be obtained.
For uncomplicated pregnancies without labor, the cerclage is usually cut and removed at 37 weeks' gestation. This balances the risk of preterm birth against that of cervical laceration from and coworkers (2014) evaluated 16 studies involving 678 pregnancies. Placement before pregnancy and during pregnancy was similar, whether performed laparoscopically or by laparotomy.