Transcript الشريحة 1
• Condition in which the cervix fails to retain the conceptus during pregnancy. • There are arguments about the occurrence and incidence of incompetent cervix Affects around 1% of pregnant patients Cervical incompetence has long been recognized as a potential cause of preterm delivery & recurrent mid trimister abortionns. It is believed that cervical incompetence is the cause of 20 - 25 % of all second trimester losses 1. Idiopathic (most cases). 2. Congenital disorders (congenital mullerian duct abnormalities eg. Septate uterus, Bicornuate uterus). 3. DES exposure in utero. 4. Connective tissue disorder (Ehlers- Danlos syndrome). 5. Surgical trauma : Conization,( resulting in substantial loss of connective tissue) or Traumatic damage to the structural integrity of the cervix : (repeated forced cervical dilatation associated with D&C). The cervical competence is an active, not passive, phenomenon, and it is a specific entity involving not just an abnormality or defect of cervical collagen, but is also due to either: 1. Absence of the usual cervical musculature in cases of congenital cervical incompetence, or 2. Injury or damage to the cervical musculature caused by previous trauma. Women with incompetent cervix typically present with "silent" cervical dilatation (i.e., with minimal uterine contractions) between 16 and 28 weeks of gestation. • Patient present with significant cervical dilatation (2 cm or more) and minimal symptoms. • When the cervix reaches 4 cm or more, active uterine contractions or rupture of membranes may occur. • The function of the cervix during pregnancy depends on the regulations of connective tissue metabolism. • Collagen is the principal component in the cervical matrix, others are: (proteoaminoglycans, elastin and glycoproteins, like fibronectin). The biochemical events implicated in the cervical ripening are: 1. Decrease in total collagen content, 2. Increase in collagen solubility and 3. Increase in collagenolytic activity. • It is a clinical diagnosis marked by gradual, painless dilatation and effacement of the cervix with membranes visible through the cervix. • This history establishes the diagnosis, eventually, women with this cervical status may develop membrane rupture & labor. • Short labors with the delivery of an immature fetus or loss of the pregnancy at progressively earlier gestational ages in successive pregnancies is characteristic of reduced competence. – Historical factors 1.History of painless cervical dilatation with preterm delivery 2.History of forceful cervical dilatation and evacuation 3.History of obstetric trauma: cervical lacerations, prolonged second stage followed by cesarean 4.Prior cervical surgery: cone, loop 5.DES exposure in utero – Cervical sonography 6.Short cervical length 7.Cervical funneling • The diagnosis is at present largely subjective and retrospective. • If possible, an objective (i.e. measurable) diagnosis, made before pregnancy or in the early stages (first or early second trimester) would provide : 1. An accurate incidence of cervical incompetence, 2. Allow treatment to be targeted appropriately and 3. Also provide the basis for definitive trials of treatment. • Dilators or balloons to determine cervical resistance and/or hysterosalpingograms to measure the width of the cervical canal between pregnancies are neither sensitive nor specific. • Digital examination of the cervix is highly subjective. • Sonography has provided a reproducible method of evaluating the cervix. • Initial use of ultrasound to observe the cervix was transabdominal but the necessity for a full bladder to visualize the cervix elongates the cervix to such a degree as to make objective, reproducible measurements difficult. • The development of transvaginal scanning (TVS) allowed for accurate cervical measurements with an empty bladder and no distortion . 'funneling' or 'breaking' of the internal cervical os ( at rest or particularly in response to transabdominal pressure on the uterine fundus ) is the ultrasonographic appearance of cervical incompetence . Cervical measurements • Provide a significant advance in the diagnosis of cervical incompetence • In contrast to the hysteroscopic evaluation of the cervix, it is : non-invasive, repeatable over time and can be performed during pregnancy. 1. Funneling of the cervix with the changes in forms T, Y, V, U (correlation between the length of the cervix and the changes in the cervical internal os). (Trust Your Vaginal Ultrasound) 2. Cervix length < 25 mm 3. Protrusion of the membranes. 4. Presence of fetal parts in the cervix or vagina 2 images of the same cervix, 20 seconds apart, without and with applying pressure: Sonographic serial evaluation ( every two weeks) of the cervix for funneling and shortening in response to transfundal pressure has been found to be useful in the evaluation of incompetent cervix. Am J Obstet Gynecol 1997;177:660-5. • Surgical repair of the cervix using a vaginal or abdominal approach. • Other alternatives that have been considered have included : 1. Bed rest, for which no trial has been conducted and for which little evidence of effectiveness exists, and 2. The use of vaginal pessaries to elevate and close the cervix. The initial descriptions of cervical cerclage for cervical incompetence came with Shirodkar and McDonald in the 1950s, when both developed techniques for physical support for what was presumed to be a structurally weak cervix. Cerclage is not indicated solely based on risk factors or prior cerclage placed for doubtful indications. Am J Obstet Gynecol 1982 Mar 1;142(5):506-12 ,Obstet Gynecol 1989 Feb;73(2),Am J Obstet Gynecol 1993 Nov;169(5):11259 PMID: 8238171,J Reprod Med 1994 Nov;39(11):880-2 PMID: Cerclage Prophylactic Emergency • Prophylactic cerclage sutures (Shirodkar, McDonald )may be placed at 12 to 16 weeks' gestation. • Do not use tocolytics at the time of prophylactic cerclage, but give perioperative antibiotics. • Intercourse, prolonged standing (>90 minutes), and heavy lifting are omitted following cerclage. • Follow these patients with periodic vaginal sonography to assess stitch location and funneling. • No additional restrictions are recommended as long as the stitches remain within the middle or upper third of the cervix without the development of a funnel, and the length of the cervix is greater than 25 mm. • For patients who have not been successful with a vaginal suture despite aggressive care and sonographic surveillance, a transabdominal cerclage may be appropriate. • Care of the patient with newly detected reduced cervical competence in the second trimester is both difficult and controversial. • When the diagnosis is made before cervical dilatation has occurred and when there is still 10 to 15 mm or more of cervical length, admit the patient for 24 hours of treatment with perioperative indomethacin and broad-spectrum antibiotics before placing the cerclage sutures, and observe the patient for 48 to 96 hours postoperatively. • However, if the cervix has dilated to allow visualization of the membranes, the patient may remain hospitalized for several days after cerclage placement. • The prognosis for these patients is better than generally expected, with many women delivering a "viable" (usually defined as >1,000 g) infant, but aggressive therapy may be required to achieve these results. • The prognosis is influenced by the gestational age at the time when the suture is placed. In the case of advanced dilatation with bulging membranes, several techniques may be helpful: 1. Pre cerclage amniocentesis to remove sufficient fluid to reduce the bulging membranes can be helpful. 2. Overfilling the bladder with 1,000 ml of saline may help by elevating the membranes out of the operative field, but may also obstruct the surgeon's view. 3. Place a Foley catheter balloon inside the cervix, and overfill it with at least 50 ml of saline to gently push the membranes out of the lower segment. The cerclage suture can then be placed and tied as the balloon fluid is evacuated. • Cerclage is rarely performed after 24 to 25 weeks of pregnancy. • The great risk of inducing PROM or preterm labor and the ability to prolong gestation with bed rest and suppressive medications argue against surgical intervention in such cases. • The cerclage is removed at 37 weeks' gestation or at the onset of labor. 1. History compatible with incompetent cervix AND 2. Sonogram demonstrating funneling OR 3. Clinical evidence of extensive obstetric trauma to cervix ACOG Criteria Number 17 October 1996, ACOG Criteria Number 18 October 1996 1.Uterine contractions. 2.Uterine bleeding 3.Chorioamnionitis 4.Premature rupture of membranes 5.Fetal anomaly incompatible with life There are five different techniques for performing the cerclage: 1. McDonald procedure 2. Shirodkar operation 3. Wurm procedure (Hefner cerclage) 4. Transabdominal cerclage 5. Lash procedure The two most common are the McDonald and Shirodkar. • The McDonald procedure is done with a 5 mm band of permanent suture is placed high on the cervix. • This is indicated when there is significant effacement of the lower portion of the cervix. • It is generally removed at 37 weeks, unless there is a reason to remove it earlier, like infection, preterm labor, premature rupture of the membranes, etc. • It is also shown that this has very little impact of the chance for vaginal delivery. • The McDonald technique requires no bladder dissection, and the cervix is closed using four or five bites with the needle to create a purse string around the cervix. • The Shirodkar is also a frequently used technique. • However, this was previously a permanent purse string suture that would remain intact for life. • There are physicians performing modified techniques, where the delivery does not necessarily have to be by cesarean, nor the suture left intact. • Place the suture as near the internal os as, opening the anterior fornix and dissecting away the adjacent bladder, before placing the suture submucosally, tied anteriorly and the knot buried by suturing the anterior fornix mucosal opening. • The original intention with the Shirodkar method was to leave the suture in place and aim for delivery by caesarean section. • Both initially started suturing with catgut, but Shirodkar turned to fascia lata and McDonald turned to ( 0 )silk as they realized the importance of a permanent cervical support. • One significant difference since then has been the present day use of Mersilene tape as the suture material. • Both the McDonald and Shirodkar cervical sutures are equally effective as a vaginal approach to cervical cerclage. • McDonald suture is generally easier to perform with no major difference in success. • The Hefner cerclage, also known 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. One further development in the 1960s was the description of the transabdominal cerclage by Benson and Durfee in 1965 a technique now largely used after the failure of vaginal cerclage procedures or in the presence of congenital anomalies, particularly those produced by diethylstilboestrol exposure. The original intention with the transabdominal approach was that the suture was inserted between pregnancies or in early pregnancy, and left in situ for the rest of the woman's reproductive life, delivery being undertaken by caesarean section for each pregnancy. • In this method, a midline or Pfannenstiel abdominal incision allows access to the vesicouterine fold of peritoneum, which is divided and the bladder reflected caudally. • The uterine vessels are then identified and a Mersilene tape suture is passed through the broad ligament below the uterine vessels in the potential 'free space' between the uterine vessels and the ureter, with the suture tied anteriorly or posteriorly (anterior being reported as surgically easier) and the bladder replaced. • The last procedure, the Lash, is performed in the non-pregnant state. • It is typically done after cervical trauma that has caused an anatomical defect. • Lash described techniques aimed at the repair of a specific anterior cervical structural defect. The cervical mucosa was opened anteriorly, the bladder reflected and the cervical defect repaired with interrupted transverse sutures before closing the vaginal mucosa. 1. Ultrasound for anomaly and viability 2. MS-AFP( Alpha Fetopritein) if appropriate 3. Wet mount.( For vaginal infections). 4. G Beta Streptococci, Gonococci, and Chlamydia cultures. Treat appropriately for infection. • • • • • • Admit for cerclage NPO after midnight Bed rest. Trendelenberg if cervix is effaced or dilated. Surgical consent A 100-mg dose of indomethacin may be given per rectum during the operative period, followed by a 50-mg oral dose every 6 hours • McDonald cerclage • Postop. ,Transfer to postpartum for observation • Regular diet • Bed rest 12-24 hours • May discharge if no uterine contractions, vaginal bleeding, or rupture of membranes during observation. 1. Premature rupture of membranes (1-9%) 2. 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.) 3. Preterm Labor 4. Cervical laceration or amputation (This can be at the procedure or at the delivery, from scar tissue that forms on the cervix.) 5. Bladder Injury (rare) 6. Maternal hemorrhage 7. Cervical dystocia 8. Uterine rupture • For elective cerclage at the beginning of the second trimester, the risk of infection is small, estimated at less than 1 percent. • Later in the pregnancy, displacement of the suture also can occur (3 to 12 percent). • A second cerclage has a much lower success rate. • Late complications of cerclage include PROM or preterm labor and chorioamnionitis. • When fluid leakage occurs in a patient with a cerclage, removal of the suture, to reduce the risk of infection is controversial. • Finally, even though cerclage placement is considered a benign procedure, a maternal death secondary to sepsis in a patient with retained cerclage has been reported. • The liberal use of this surgical procedure should be carefully balanced against potential harm, in particular for patients in whom the indications for cerclage are not clear. • Cerclage seems to be a very effective treatment for incompetent cervix. • The success rates can be very high (80-90%), particularly when done earlier in a pregnancy. • Cervical incompetence is often over-diagnosed as a cause of mid-trimester miscarriage. • Cervical cerclage should only be considered when the history of miscarriage is preceded by spontaneous rupture of membranes or painless cervical dilatation. • The MAC/RCOG trial of the use of cervical cerclage reported a small decrease in preterm birth, but no significant improvement in fetal survival. (Grade B recommendation) • Transabdominal cerclage performed preconceptually has been advocated as a treatment for second trimester miscarriage and the prevention of early preterm labour. • The reported improvement in pregnancy outcome is difficult to assess in the absence of a control group.