Questions about TACs – A.F. Haney, MD (University of Chicago)
February 8, 2015
1) Who is a candidate for a TAC?
The TAC has traditionally been reserved for women with an incompetent cervix (IC) who have a) already failed a transvaginal cerclage (TVC), b) have too short a cervix to place a TVC because of a previous LEEP or cold knife conization (CKC) for cervical dysplasia or c) have torn the cervix from a previous cervical tear at a delivery (often a rapid delivery with a TVC in place). I personally believe any woman with IC is a candidate for a TAC as compared to the TVC a with a TAC 1) there is a higher rate of living children, 2) there is a much lower rate of preterm birth, 3) no bed rest or modification of activity during pregnancy is required, 4) it need not be removed allowing multiple deliveries and 5) a C-section is not a reason to favor a TVC. My prediction is that in a short period of time, the TAC will replace the TVC as primary treatment for IC.
2) How is the TAC different from the TVC?
While the TVC and the TAC both try and provide structural support for the cervix, they are completely different. The TVC is a purse string suture placed as high in the vaginal portion of the cervix as possible, closes the cervical canal so is placed around 12 weeks after the miscarriage risk has passed, is technically simple to place and can be removed easily allowing a vaginal delivery. Because the TVC closes the cervical canal, it must be placed during pregnancy. However, the TVC only protects the vaginal portion of the cervix (~ 1/3rd of the total cervical length), usually requires bed rest, results in living children ~ 75% of the time and is associated with a high rate of pre-term delivery with the attendant risks of a prolonged NICU stay. By contrast, the TAC supports the entire cervix as it is placed at the very top, results in living children > 98% with most being term deliveries (> 36 weeks), albeit by C-section, does not require bed rest or a modification of activities during pregnancy but is placed through an abdominal incision. Since TACs are placed by a relatively small number of physicians in the US, the TVC is most often recommended as the initial treatment for IC. They have not been directly compared as primary treatment since TACs have been considered as secondary treatment after TVC failures. However, since the TAC has a much higher success rate than the TVC with few preterm deliveries with a low complication rate, TACs will increasingly be viewed as the superior choice for the primary treatment of IC.
3) In layman’s terms, describe the TAC procedure (the “open” method and the laparoscopic/robotic technique).
The basic principle of a TAC is to place a flexible, extremely strong, non-elastic band around the very top of the cervix to resist the gravitational pressure of the enlarging pregnancy and prevent opening of the top of the cervix, e.g., funneling. Since the top of the cervix is in the abdominal cavity, the TAC can only be placed by an abdominal operation, either by an open or endoscopic (laparoscope or robot) technique. The band is made of a non-reactive woven polyester (Mersilene®) and placed around the top of the cervix immediately under both uterine arteries. It is tied with enough tension to prevent funneling without compromising the vascularity of the cervix itself. This allows the normal uterine artery blood flow to increase during pregnancy and mimics the normal support present in women without IC.
The open technique uses a “mini” version of the low transverse “bikini” incision at the pubic hair line used for C-sections. I personally prefer the open incision to either the laparoscopic or robotic approach. The reasons for this are that a) my experience is that the failure rate of the laparoscopic and robotic techniques is higher than the open technique, b) the endoscopic approaches require additional incisions from that used to perform the C-section, c) all can be done as outpatient surgery and d) the recovery is virtually identical when done prior to pregnancy.
The laparoscopic and robotic techniques have not been directly compared with the “mini” open technique and the majority of published reports for TACs have used the open approach. As with all purported surgical advances, the minimum requirement before adopting a new technique is that it be at least as successful as the standard technique. While the endoscopic approaches will undoubtedly improve, I have had to replace a number of TACs which failed and were placed by the laparoscopic and robotic approaches. When the TACs were replaced through an open incision they have been uniformly successful. Until these surgical techniques are directly compared in a well-designed clinical trial by experienced surgeons, the optimal approach will remain a personal judgment of the surgeon and an informed patient.
3) What are the benefits and/or disadvantages of having the TAC placed prior to pregnancy and during pregnancy?
The only reason to place TACs during pregnancy is historic as that is how they were first performed in the 1960s based on the concept that the “TAC is a TVC placed higher”. Surgery was typically done around 15-16 weeks, through a vertical mid-line incision (from the pubic bone to above the navel). This timing avoided placing a TAC when a 1st trimester genetic miscarriage might occur necessitating a second operation to remove the TAC as it was thought to close the cervical canal as the TVC does. Ultrasound scanning was not available and the only way to tell the pregnancy was viable was by hearing the fetal heart tones. However, it is now apparent that the TAC does not close the cervical canal and it can be placed prior to pregnancy. If a 1st trimester miscarriage occurs, the tissue may be spontaneously passed, Cytotec® can be used to cause expulsion or a D&C can be done without any impact on the success of the TAC in a subsequent pregnancy. Placing a TAC during pregnancy it is typically between 9 and 12 weeks after viability is confirmed by ultrasound.
Placing the a TAC during pregnancy has the disadvantages of 1) performing surgery during pregnancy, 2) a higher risk of bleeding with the increased vascularity, 3) being technically more difficult to place the band at the top of the cervix because the larger uterine size, 5) not being able to remove fibroids or other pathology when they interfere with the TAC placement and 6) a risk that funneling of the cervix has already begun, increasing the risk of failure.
Placing the TAC prior to pregnancy has none of those disadvantages and allows the TAC placement to be done as an outpatient procedure. Placement prior to pregnancy does not alter menses or fertility, and there is no problem transferring embryos in women undergoing IVF. Ultimately, placing the TAC prior to pregnancy will be the preferred approach regardless of the surgical technique utilized.
4) During pregnancy, which types of anesthesia are safe and which do you prefer for placement of a TAC?
Both general and spinal anesthesia are safe. I personally only place open TACs during pregnancy under general anesthesia as the spinal does not relax the abdominal muscles adequately to allow reliable and safe access to the uterine arteries under which the TAC is placed. Placing a TAC before pregnancy can be done safely with either anesthetic approach and is the patient preference unless a longer surgery is anticipated because of other issues (fibroids, adhesions, etc.).
5) If the woman is pregnant, during which week of pregnancy should the TAC be placed and why?
If funneling has already begun (cervical shortening), a TAC should not be placed as the membranes have already detached from the inside of the uterine cavity and further descent downward is virtually impossible to stop. Essentially there is no “rescue” TAC like the “rescue” TVC. Funneling before the TAC was placed was the cause of failure of the early TACs when ultrasound was not available to detect funneling. Placing the TAC prior to funneling is accomplished by lowering the gestational age when it is placed after viability is determined by ultrasound. The lower limit when a TAC can safely be placed during pregnancy has not been determined. Since miscarriages are common, it would be difficult to distinguish a genetic miscarriage occurred after a TAC from a loss related to the surgery. I have observed funneling as early as 11 weeks with a singleton so my current approach is to place TACs between 8.5 to 10 weeks after ultrasound has documented normal fetal growth on consecutive interval scans. Obviously, the ultimate timing is prior to pregnancy avoiding the entire issue of funneling, hence, my preference for placing pre-pregnant TACs.
6) If the TAC is placed pre-pregnancy, how long after a loss should one wait before the surgery?
The optimal success rate is when the TAC closely encircles the non-pregnant cervix which requires that the cervix has returned to its pre-pregnancy size. In my experience, this is approximately 90 days from the loss. Placing a TAC earlier risks a lower success rate because the TAC will be too large when the cervix shrinks to normal.
7) What are the estimated recovery times when a TAC is placed prior to or during pregnancy?
When placed prior to pregnancy through a “mini” transverse incision, laparoscopy or the robot, the TAC surgery can be done as an outpatient. There are no restrictions to activity except driving for 7 days. Activity such as walking reduces the risk of blood clots and the more the activity the better. The driving restriction is related to the distraction effect of incisional discomfort which can increase the risk of an accident, (comparable to the distraction of texting while driving). When the TAC is placed during pregnancy, the recovery time varies by the technique and usually requires a few extra days. Additionally, many pregnant women experience nausea and vomiting during early pregnancy which is exacerbated by anesthesia and surgery which may also slow the recovery.
9) If the surgery is done during pregnancy, what type of prescription or over-the-counter pain medications are safe?
When used for the short interval of postoperative discomfort, all the intravenous and oral narcotics are safe during pregnancy. Non-steroidal anti-inflammatory medications (ibuprofen and naproxen) and acetaminophen are also safe to use. Taking a stool softener to minimize the constipating effect of narcotics is very helpful as well.
10) Is there a possibility of delayed success in getting pregnant with the TAC in place?
A TAC placed prior to pregnancy has no impact on menses, fertility, the time to conception, etc. The TAC simply encircles the top of the cervix and does not have any effect on the tubes and ovaries. If infertility treatment (IUI, IVF, etc.) is required to conceive before the TAC, then that will be required afterward as well. If no problem existed in conceiving prior to the TAC there will be no problem after a TAC.
11) How long should one wait before trying to conceive with a TAC in place?
If there is no other surgery needed at the time of the TAC placement such as the removal of fibroids, you can attempt pregnancy immediately. Many women have conceived on their next cycle without any resultant pregnancy problems. Occasionally the stress of surgery may cause the next ovulation to be delayed but within a month or two normal ovulation returns.
12) Is pelvic rest necessary during pregnancy? Is orgasm OK?
Avoiding intercourse during pregnancy is not necessary with a TAC because the entire normal length of the protective cervical mucus column is maintained. This is in contrast to the TVC which only protects the lower 1/3rd of the cervical mucus column at most. Some physicians recommend that women with a surgically-shortened cervix after a LEEP or cold knife conization (CKC) refrain from intercourse but I have not prohibited intercourse in any women with TACs and not encountered any problems. Orgasm does not impact the cervix or uterus and is perfectly fine.
13) Is bed rest necessary and at what point?
Bed rest improves the outcomes with TVCs but is of no benefit with a TAC as the support is at the top of the cervix, is far stronger than the weight of a term pregnancy thus taking gravity out of consideration.
14) With a TAC in place, how far in centimeters can one dilate without being harmful to the mother or baby?
The dilation that women with IC experience occurs only after the membranes have completely funneled down to the vaginal opening of the cervix. Since the TAC prevents funneling at the top of the cervix, cervical dilation does not occur.
15) If a 1st trimester miscarriage occurs, can a woman with a TAC in place “let nature take its course” or is it safe to request a D&C? What are the dangers of either method?
A TAC placed prior to pregnancy does not prevent spontaneous passage of the degenerating tissue when a 1st trimester miscarriage (typically between 6 and 10 weeks). If that does not occur naturally, Cytotec® can be administered to cause expulsion of the tissue. A D&C can be performed if the process is delayed or significant bleeding occurs without any impact on the success of the TAC in the subsequent pregnancy. It is generally better to see if spontaneous expulsion will occur to avoid surgical manipulation of the cervix. Since the TAC, in contrast to a TVC, does not constrict the cervical canal, there is no impact of a TAC on a 1st trimester miscarriage which is one of the biggest misperceptions related to TACs.
16) What is the risk of losing a pregnancy because of an incompetent cervix after 12 weeks with a TAC in place?
The TAC is by far the most successful treatment for IC with the success rate of living children exceeding 98% as well as dramatically reducing the risk of preterm birth compared to the TVC. The risk of a TAC failing depends on a variety of factors including 1) the experience of the surgeon, 2) the surgical technique used and 3) other individual patient factors. It is important to remember that every woman is unique and that a woman’s individual medical circumstances can affect the success rate. Individual patient factors include 1) placing the TAC during pregnancy when funneling may have already begun (typically > 10 weeks), 2) a previously surgically shortened cervix by a LEEP or CKC, 3) a previous obstetrical cervical tear (often caused by a rapid delivery before a TVC could be removed), 4) other pathology such as fibroids close to the cervix, other pelvic pathology or previous surgery, 5) loss of structural integrity of the cervix from surgical injuries to the cervix during a D&C or hysteroscopy, 6) cysts within the cervix and 7) genetic issues such as connective tissue disorders like Ehlers-Danlos syndrome. While the TAC very effectively treats IC, it does not prevent other obstetrical problems such as pre-eclampsia, gestational diabetes, hypertension, rare random birth defects, etc.
17) During what week gestation, should a C-Section be performed?
If no other obstetric issues arise, the he C-section should be performed after 38 weeks or if labor begins prior to that time. A weekly non-stress test (NST) beginning at 36 weeks can provide reassurance of normal placental function so as to insure it is safe to wait till 39 weeks. It is important to distinguish true labor (regular persistent contractions) from episodic Braxton-Hicks contractions which all pregnant women experience. The frequency of pre-term labor is low in women with TACs but certainly can occur as an independent problem.
18) How many pregnancies can I have with the TAC in place?
There is no specific limit and I have personally had women have 4 term deliveries after a TAC. I encourage leaving the TAC in place until you are absolutely sure that you do not want any more children under any circumstances. The band material used for a TAC (Mersilene®) is inert and does not cause a tissue reaction and there are no problems if subsequent gynecologic surgery becomes necessary. If you are not planning another child but are hesitant to have permanent sterilization (tubal ligation or vasectomy), leave the TAC in place and simply use contraception. As many couples with IC have never experienced anything but losses, their perception of how many children they want may change after a term delivery. I do not want any couple to feel regret and limit their family size until they are completely confident they want no more children.
19) At what point would a fetal demise or major birth defects incompatible with life require a small C-section?
Luckily, these are very infrequent events and a D&C can be done up to about 12-13 weeks. After that point, a smaller version of a C-Section is required because of the size of the fetus. Every effort should be made to determine the cause of these problems in hopes of being able to prevent a recurrence. In the majority of cases, however, no etiology will be identified but the likelihood of recurrence can still be estimated.
20) How often should cervical length be measured via transvaginal ultrasound throughout pregnancy?
I recommend measuring the cervical length every two weeks from 12 weeks to 20 weeks or past the time of a previous loss. Observing no cervical funneling as the pregnancy progresses is very reassuring lessening the inevitable anxiety. Beyond 20 weeks, you can be very confident that the TAC has effectively supported the cervix and will continue to do so throughout the pregnancy.
The cervical length measurement that can vary from one scan to the next based on 1) the subjective judgment made by the ultrasound technician as to where the cervix begins and ends, 2) whether they measure following the curvature of the cervical canal or as a straight line, 3) the fullness of the bladder and 4) the angle of the scan. The important issue is not the precise cervical length rather that the baby and membranes remain above the level of TAC (an imaginary line between the echoes of the TAC in front and behind the cervix). This assures that the TAC is preventing funneling and does not depend on the scanning technique. Since encircling the cervix requires the band to be imbedded in the dense connective tissue on either side of the cervix, it cannot “slip” or move downward.
21) Should manual (digital) exams be performed regularly throughout the pregnancy?
With a TAC in place, there is no value of doing manual exams to monitor the cervix as is done with TVCs. The only way to assess what is happening at the top of the cervix is by ultrasound as the TAC is well above the vagina. Manual exams are generally not harmful as the cervix remains unchanged and long but it indicates that the obstetrician does not fully understand how the TAC works and where it is. Ultrasound visualization of the cervix is the primary tool to utilize both for routine monitoring and evaluating any symptoms. There is no concern with a vaginal ultrasound as, in contrast to a manual exam, it does not probe the cervical canal.
22) How does TAC work in women who conceive twins? How about in the case of high order multiples?
The TAC is extremely strong and makes the cervix better supported than a woman without IC. My experience in women with IC and twins and a TAC is that they do as well or better than women without IC who have twins. Simply put, the weight of a twin pregnancy is not an issue. Twins often are delivered somewhat early not because of cervical issues but because of fetal growth issues. A woman’s ability to provide enough oxygen and nutrients varies and with two babies and higher demand it may exceed the supply in the middle of the 3rd trimester. If one baby’s growth rate slows, it is time for delivery. While there is very little information about multiples beyond twins with TACs, I do not think triplets will exceed the support provided by the TAC and the issue will again be babies’ growth rates. The timing of the delivery will shift to growth indicators and ultrasound monitoring of the babies’ growth becomes paramount.
23) Is "funneling" a problem with the TAC?
As noted earlier, the primary reason that the TAC has a higher success rate compared to the TVC is that it prevents funneling as it is placed at the very top of the cervix. In rare circumstances funneling below the level of the TAC can occur when the TAC could be optimally placed or when the integrity of the connective tissue of the cervix has been compromised, usually by the trauma of multiple surgeries. Examples are when a distorting fibroid is present near the top of the cervix and the TAC is placed during pregnancy or if cervix has been damaged by surgical procedures or obstetric lacerations. For all practical purposes, the likelihood of funneling below the level of the TAC is extremely low whereas with a TVC, funneling to the level of the cerclage always occurs.
24) How is preterm labor handled in a patient with a TAC?
The short answer is exactly the same as in women without IC. Luckily, preterm labor (PTL) with a normal length cervix is an infrequent obstetric problem (~ 5%) and PTL is not increased in women with IC and a TAC. With untreated IC, the cervix shortens allowing an infection of the amniotic fluid by vaginal bacteria resulting in contractions. Cervical shortening is precisely what the TAC prevents so women with TACs have the same risk of PTL as women without IC and a normal length cervix. With any IC loss contractions often occur after the cervix shortens and it is not surprising that many obstetricians label this PTL when in fact the contractions are the result of a shortened cervix, not causing shortening the cervix. It is important to recognize that non-harmful Braxton-Hicks contractions occur in every pregnancy but after IC losses, they understandably cause a great deal of anxiety. Anticipating that Braxton-Hicks contractions will occur and distinguishing them from PTL is the key. With a TAC in place, the standard treatments for PTL are just as effective. These include intravenous hydration, tocolytics such as terbutaline, non-steroidal anti-inflammatory drugs (NSAIDs) and magnesium sulfate, and Procardia among others.
Preventing preterm birth by the use of progesterone in any form (shots, vaginal suppositories, or pills) shots has received renewed interest and it has been shown to prolong pregnancies in women with a history of true PTL. However, it has never been independently demonstrated in women with 2nd trimester losses from IC. Since progesterone is naturally made by the placenta and has no demonstrated risk, many obstetricians recommend its use with TACs under the philosophy that “can’t hurt, might help”. Progesterone may have a theoretical benefit in women with IC and a surgically shortened cervix from a previous LEEP or CKC but that has not been demonstrated. Given the emotional devastation of an IC loss, using progesterone to be sure everything has been done to prevent another loss even without data of effectiveness is certainly acceptable. However, progesterone should not be used as an alternative to a cerclage as there is no evidence that it protects against funneling or is effective in women with 2nd trimester IC losses.
25) What is the success rate of TAC?
Virtually all women with TACs deliver > 36 weeks both when the TAC is placed prior to or during pregnancy. While not perfect, the TAC results in ~ 98-99% living children with a low rate of preterm delivery. The results with a TVC and bed rest are ~ 75% chance of a having a living child, and with a high rate of preterm birth with a lengthy NICU stay risking life-long disabilities. As TACs have historically been used as secondary treatment after failure of a TVC and the results of TAC in that setting are dramatically better, there is no doubt that a TAC will have the same high success rate when used as primary treatment for IC. The need for a C-section with a TAC is inconsequential when compared to the risks of a loss or preterm birth with a TVC.
26) How many TACs have you performed?
I have been placing TACs for over 30 years but did not keep detailed records in my previous position at Duke University. I came to the University of Chicago in 2003 am currently placing over 200 TACs per year. Most of these are in women who live in other states or outside of the US and fly to Chicago for their TAC.
27) Are there any other things you would like to add or do you have further comments?
Every woman with a TAC is unique.
It is worth repeating that every woman is unique and that individual medical circumstances can affect the success rate of a TAC. I is optimal to consider your individual situation rather than issues which are not pertinent. Individual patient factors include: 1) placing the TAC during pregnancy when funneling may have already begun (typically > 10 weeks), 2) a surgically shortened cervix after a LEEP or CKC, 3) a previous obstetrical cervical tear (often caused by a rapid delivery before a TVC could be removed), 4) other pathology such as fibroids, other pelvic pathology or adhesions from previous surgery, 5) loss of structural integrity of the cervix from either surgical injuries to the cervix during a D&C or hysteroscopy or congenital cysts within the cervix and 6) genetic issues such as connective tissue disorders like Ehlers-Danlos syndrome.
The diagnosis of an Incompetent Cervix
Comments that the loss of a viable baby between 14-25 weeks was just “bad luck” or “one of those things” are simply not supported by evidence. The loss of a baby in the 2nd trimester should be considered IC until proven otherwise. There is no evidence that preterm labor, spontaneous intra-uterine infection (chorioamnionitis), or premature placental separation (placental abruption) can occur this early in pregnancy in the absence of an obvious causal event. The notion that “to make the diagnosis of IC” the loss would have to occur without any contractions is simply untrue. Almost all women with IC will eventually have contractions in the course of their loss and may rupture their membranes as the normal mucus barrier to ascent of vaginal bacteria is lost when the cervix funnels. If not treated, the same cervical changes and loss has an extremely high likelihood of happening again in the next pregnancy. Similarly, placing another TVC after a TVC has failed is extremely likely to result in another loss.
The TAC is “too dangerous”
The often repeated comments that a TAC is too “invasive”, “dangerous”, “overkill” and should only be used after several failed TVCs is based on the risks encountered when TACs were first introduced in the 1960s and is simply unjustified by contemporary literature. Since placing a TAC carries far less risk than a C-section, there is simply no current rationale for this concept. Any parent knows that losing their babies is far more traumatic than placing a TAC or a C-section.
Coexistent uterine fibroids
Fibroids are extremely common and do not cause IC. However, a fibroid may be present in the lower portion of the uterine muscle and prevent correct placement of a TAC. If the TAC is placed prior to pregnancy, a lower segment can easily be removed but that cannot be done when pregnant. Doing a myomectomy obligates the woman to a C-section but since she must have one anyway with a TAC, this is not an issue. All women with IC and coexistent fibroids should have their TAC placed prior to pregnancy.
The Type of C-section needed with a TAC
Obstetricians without experience with TACs are not thinking about the type of uterine incision used for the C-section in women with a TAC. However, they have certainly done them many times and have no difficulty with them once they are made aware of the situation. The C-section with a TAC should be done through a low transverse “bikini” skin incision despite a higher uterine incision similar to the vertical “Classical” C-section. The only implication with this type of uterine muscle incision is that a subsequent vaginal birth (VBAC) should not be attempted but since everyone with a TAC requires a C-section regardless, that is not an issue. Every obstetrician regularly does this type of C-section so this should this should not an issue.
Insurance coverage for TACs as primary treatment for IC
As noted earlier, the TAC is the most successful and cost-effective primary treatment for IC. Many large health insurance companies have analyzed their experience with TVCs and TACs and readily cover the TAC as primary treatment. Sadly, many medium and small insurance companies do not do any analysis of outcomes or have too few patients with IC. They tend to utilize the older 1960s concepts that the TAC should only be considered after the failure of a TVC or when the woman has previously had a LEEP, CKC or an obstetric laceration. Many of their consultants who do not place TACs reinforce this concept and they may deny a TAC until a TVC fails to their own detriment. This will change over time but many couples are currently caught in this frustratingly slow transition. It is always wise to appeal and request that any denial be based on the contemporary literature not a “clinical opinion” which is universally recognized as having the lowest level of reliability.
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