CERVICAL INCOMPETENCE Dr Muhammad El Hennawy Ob/gyn specialist Rass el barr central hospital and dumyat specialised hospital Dumyatt – EGYPT www.geocities.com/mmhennawy

Cervical incompetence(CI) It is premature painless diltation of endocervical canal in pregnancy before onset of labour

Incidence It is estimated that cervical incompetence will complicate anywhere from 0.1% to 2% of all pregnancies and is thought to be responsible for approximately 15% of habitual immature deliveries between 16 and 28 weeks of gestation

the etiology In most cases, the etiology is unknown Known causes include Congenital weakness as Mullerian abnormalities (cervical hypoplasia, in utero diethylstilbestrol [DES] exposure), traumatic abnormalities (prior surgical or obstetric trauma), and connective tissue abnormalities (Ehlers-Danlos syndrome).

Cervical Anatomy Embryologically, the body and cervix of the uterus are derived from fusion and recanalization of the paramesonephric (Mullerian) ducts, a process that is complete by the 5th month of pregnancy. Histologically, the cervix consists of fibrous connective tissue, muscle, and blood vessels. Muscular connective tissue constitutes approximately 15% of the cervical stroma, but is not uniformly distributed throughout the cervix, constituting approximately 30%, 18%, and 7% of the upper, mid, and lower thirds of the cervix, respectively (2). Conversely, the fibrous connective tissue content of the cervical stroma increases as one moves from the external os to the uterine corpus, and it this component that is believed to confer tensile strength to the cervix. Defects in tensile strength are thought to lead to premature cervical dilatation and pregnancy loss.

Despite many advances in modern obstetrics ,there remains much controversy regarding the diagnosis and treatment of cervical incompetence

Diagnosis There is no precise method for diagnosing CI Strongest evidence for diagnosis of CI is lack of any other causes for reccurrent pregnancy loss eg : chromosomal abnormalities,infection,endocrine disorders,immunologic disease) With history of consistent with condition . - Or + Pre-pregnancy physical findings Ultrasonography is useful as adjunct to other diagnostic measures

history of consistent with condition Painless premature cervical diltation during pregnancy and before onset of labour a sudden unexpected rupture of the membranes followed by painless expulsion of the fetus Resulting in repeated mid trimester spontaneous miscarriage or premature delivery

- Or + Prepregnancy physical findings Ability to introduce a number 8 Hegar dilator or equivalent through the internal os when patient is not pregnant. Hysterosalpingogram demonstrating cervical funneling. Clinical evidence of extensive obstetric or surgical trauma to cervix.

Ultrasonography is useful before cerclage – length of cervical canal , width of isthmus , funneling of upper part of cervical canal with protrusion of the membranes(when the cervical os (opening) is greater than 2.5 cm, or the length has shortened to less than 20 mm. Sometimes funneling is also seen ) After cerclage – determine exact site of cerclage,proximal cervical canal segment length above cerclage ,distal cervical canal segment length below cerclage,internal os diameter ,funneling if present , and protrusion of membranes) Negative U/S can not exclude CI Positive U/S in routine screen in pregnant women without history of pregnancy loss are not necessary at risk but close follow up is required

ttt REST CERCLAGE or encerclage.

The alternative to cerclage strict bed rest, sometimes in the Trendelenburg position. However, when women with midtrimester membrane prolapse are managed expectantly, preterm prelabor rupture of membranes occur in a great majority of cases. These women rarely maintain the pregnancy for an appreciable length of time.

There's no guarantee that a cerclage will prevent a pregnancy loss; however, in most instances it will prolong the pregnancy, often enabling a woman to carry to term. You may be at risk for incompetent cervix if you have had a previous pregnancy loss in the second trimester, if you have had surgery on your cervix, or if you have had multiple pregnancy terminations

Indications Suspected cervical incompetence remains the only acceptable indication for cervical cerclage. Indications can be classified as follows: (1) Prophylactic (elective) cervical cerclage (2) Asymptomatic women with sonographic evidence of cervical shortening and/or funneling may also benefit from cervical cerclage (often called urgent cerclage) (3) Emergency (salvage) cervical cerclage Cerclage should be delayed until after 14 weeks so that early miscarriage caused by other factors is possible. There is no consensus about how late in pregnancy

1- Prophylactic (elective) cervical cerclage Decision to perform cerclage must be made individually for each patient There's no guarantee that a cerclage will prevent a pregnancy loss; however, in most instances it will prolong the pregnancy, often enabling a woman to carry to term Once CI has been strongly suggested by combination of history(asymptomatic women with a history of prior pregnancy loss and/or preterm delivery due to cervical incompetence)clinical and U/S suggested findings Prophylactic cervical cerclage may be placed because the probability of recurrence in a subsequent pregnancy is 15-30% It may be placed prior to pregnancy, but is more commonly placed between 10 -16 weeks’ gestation. The stitch is usually removed around 37 weeks and labour ensues fairly rapidly if the diagnosis was correct. Abdominal cerclage requires an elective caesarean section and the stitch is usually left in-situ for future pregnancies.

In order to avoid unnecessary elective cerclage there is a growing tendency to delay it until evidence of cervical changes at ultrasound scan appears---- urgent cervical cerclage.

2 - urgent cervical cerclage although the data in this regard is controversial. There are several retrospective studies suggesting that cervical cerclage in asymptomatic women with short cervical length and/or funneling on endovaginal ultrasound may improve perinatal outcome These studies reported an overall reduction in the incidence of preterm delivery in women identified as having a short cervix by transvaginal sonography before 24 weeks’ gestation and subsequently treated with cerclage to approximately 10% of controls. However, more recent studies suggest that cerclage does not prevent preterm delivery in women at high-risk for preterm birth on the basis of cervical shortening Moreover, one study showed a higher rate of preterm PROM in women who received a cerclage as compared with those without cerclage Further studies are awaited to clarify this issue.

3- Emergency (salvage) cervical cerclage refers to placement of a cerclage in the setting of significant cervical dilatation and/or effacement prior to 28 weeks’ gestation and in the absence of labor. it is a surgical procedure without proven benefit and with well-defined operative risks. As such, until adequate clinical trials are available demonstrating a clear benefit, emergency cerclage should be used judiciously and only after extensive and comprehensive patient counseling. achieved fetal survival of 80% with cerclage at a cervical dilatation of less than 5 cm, and 24% when cervical dilatation was 5 cm or more

Emergency cervical cerclage Contraindications: 1.Uterine contractions. 2.Uterine bleeding 3.Chorioamnionitis 4.Premature rupture of membranes 5.Fetal anomaly incompatible with life

Preoperative evaluation Cerclage should generally be delayed until after 14weeks so that early abortions due to other factors will be completed Obvious cervical infection should be treated, cultures for gonorrhea, chlamydia, and group B streptococci are recommanded Sonography to confirm a living fetus and to exclude major fetal anomalies For at least a week before and after surgery , there should be no sexual intercourse More advanced the pregnancy, the more likely surgical intervention will stimulate preterm labor or membrane rupture

Choice of cervical cerclage the decision of which technique to use can be left to the discretion of the operator.Under certain circumstances, however, one or other technique may be preferable The most commonly employed techniques are performed vaginally Shirodkar(itself and modified) and McDonald cerclage ( burried and unburried )and a transabdominal cervicoisthmic approach or Uterosacral cardinal ligament cerclage is sometimes used For example, if the cervix is very short or lacerated, a Shirodkar cerclage may be technically easier to place The transabdominal route is beneficial in treating patients with cervices that are either extremely short, congenitally deformed, deeply lacerated, or markedly scarred because of previously failed transvaginal cerclage procedures In cases where there has been extensive cervical trauma or an anatomical defect, this stitch can be used. It is permanent and requires a cesarean delivery--- The Lash cerclage.

The Lash cerclage is the only type that is placed prior to pregnancy. In cases where there has been extensive cervical trauma or an anatomical defect, this stitch can be used. It is permanent and requires a cesarean delivery.

Shirodkar technique With the Shirodkar technique, the vaginal mucosa membrane is elevated. A band of homologous fascia or narrow band of some material such as Mersilene is wrapped around the internal os and tied. The vaginal mucosa is then restored to its original position and sutured. The Shirodkar can be both permanent (requiring a cesarean section) or it can be removed near term. This stitch is started at a 12 o’clock position, worked through the cervix to a 6 o’clock position, ending back in the 12 o’clock position on the other side of the cervix. It is also pulled tightly and tied to keep the cervix closed. How the stitch is tied off determines whether it will be removed or if it is permanent.

Modified Shirodkar’s technique It is done under general anaesthesia. Cervix is exposed and held with sponge holding forceps. A transverse incision is taken over anterior lip of cervix at junction of portiovaginalis and vaginal rugosity. Bladder is separated and pushed off from area of internal os. With the help of two large curved round body needles ligature of black silk is passed starting from the edge through substance of cervix and taken out posteriorly, perpendicularly. Similar procedure is repeated on other side. Knot is tied posteriorly in the midline keeping it exterior. Anterior incision is sutured by few interrupted sutures using an absorbable material. This procedure differs from Shirodkar’s encerclage as the needle is not passed submucosally, but through substance of the cervix and no incision is taken posteriorly. The knot is kept exterior to facilitate easy removal of suture.

McDonald technique a simpler procedure, a non-absorbable suture in placed around the cervix high on the cervical mucosa stitch is weaved in and out of the cervix and pulled tightly and tied to keep the cervix closed.

The Hefner cerclage when incompetent cervix is diagnosed later in pregnancy. It has an added benefit when there is little cervix to work with. This cerclage is removed closer to term as well. also know as the Wurm procedure, is used for later diagnosis of the incompetent cervix. It is usually done with a U or mattress suture, and is of benefit when there is minimal amounts of cervix left.

Transabdominal cerclage is not frequently performed is only indicated for those patients with previous failed cervical cerclages, shortened or amputated cervix, and/or deep traumatized cervix The surgical technique -- caudal reflection of the bladder, placement of an encircling A 5mm wide mercilene tape medial to the uterine vessels in an avascular space above the junction of the cervix and the uterine isthmus without dissection or tunneling among broad ligament vessels above the cardinal and uterosacral ligaments , and tying of the knot posteriorly. This prevents erosion of the knot into the base of the bladder and allows for removal via posterior colpotomy in an emergency situation. Most agree that removal of the suture should occur after the woman has completed her family

Complication While these procedures are life-saving, they also have potential risks: Premature rupture of membranes (1-9%) Chorioamnionitis (Infection of the amniotic sac, 1-7%) (This risk increases as the pregnancy progresses and is at 30% for a cervix that is dilated more than 3 cms.) Preterm Labor Cervical laceration or amputation (This can be at the procedure or at the delivery, from scar tissue that forms on the cervix.) Bladder Injury (rare) Maternal hemorrhage Cervical dystocia Uterine rupture

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