Five-Step Laparoscopic Resection of Cesarean Scar

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What is The Five-Step Approach to Laparoscopic Resection of a Cesarean Scar Pregnancy?

A Cesarean Scar Pregnancy (CSP) is a rare form of ectopic pregnancy where the embryo implants within the scar of a previous Cesarean section. Early diagnosis and appropriate treatment are crucial to prevent complications such as severe hemorrhage or uterine rupture. One surgical option is the five-step approach to laparoscopic resection, a minimally invasive technique for removing the pregnancy while preserving uterine integrity.

The five-step approach consists of the following:

• Step 1: Preoperative Evaluation
  Pre-surgical evaluation involves confirming the diagnosis of CSP using imaging techniques like transvaginal ultrasound and MRI. These scans help determine the exact location of the pregnancy and assess the depth of invasion into the uterine scar.

• Step 2: Uterine Manipulation and Visualization
  The laparoscopic procedure begins by placing a uterine manipulator to help visualize the cesarean scar and pregnancy. Laparoscopy provides real-time visual access to the pelvic cavity, allowing the surgeon to assess the anatomy before proceeding with resection.

• Step 3: Creation of Hemostatic Control
  Hemostatic techniques, such as temporary uterine artery occlusion or vasoconstrictive agents, are applied to reduce blood flow to the cesarean scar area. This step minimizes the risk of excessive bleeding during the resection process.

• Step 4: Resection of the Pregnancy and Scar Tissue
  The pregnancy tissue and any associated scar tissue are carefully excised from the uterine wall using laparoscopic tools. Surgeons take great care to avoid perforating the uterus or damaging surrounding organs.

• Step 5: Reconstruction of the Uterine Wall
  After the resection, the uterine wall is reconstructed by suturing the defect created in the scar area. This step helps restore the uterine structure, reducing the risk of complications in future pregnancies.

What are the Risks of The Five-Step Approach to Laparoscopic Resection of a Cesarean Scar Pregnancy?

Video Transcript: The Five-Step Approach to Laparoscopic Resection of a Cesarean Scar Pregnancy?

The Five-Step Approach to Laparoscopic Resection of a Caesarean Scar Pregnancy. The objectives of this video are to review diagnostic principles for caesarean scar pregnancies and to demonstrate a simplified approach to resection. The caesarean scar pregnancy, or CSP, refers to a pregnancy that is implanted on or in a scar from a prior caesarean delivery. CSPs represent 6% of all ectopic pregnancies in patients with a prior caesarean section.

The sonographic criteria in the first trimester includes a pregnancy located in the anterior uterine isthmus, an empty uterine cavity with no contact with the gestational sac, empty cervical canal, discontinuity in the anterior myometrium, and an absence of suspicious adnexal masses or free fluid.

It is generally accepted that there are two types of CSPs. Type 1s are characterised by progression of the pregnancy to the cervicoisthmic space or uterine cavity. In Type 2s there is a deep invasion of the caesarean scar defect itself, with growth towards the bladder and abdominal cavity. The natural history of a Type 1 CSP is the development of placenta accreta spectrum, while Type 2 CSPs are predisposed to first or second trimester uterine rupture.

While expectant management may be cautiously undertaken in some Type 1 CSPs and there may be a role for systemic methotrexate or local embryocidal injection in stable patients with objections or contraindications to surgery, operative management is typically the mainstay of definitive treatment in our experience.

The optimal surgical approach is largely determined by the type of caesarean scar pregnancy. Type 1s can often be treated by hysteroscopy, whereas Type 2s may be better approached with laparoscopy, allowing for concurrent repair of the caesarean scar defect. The approach described today will address the latter type.

 The patient described in this case is a 36-year-old woman who presented at nine weeks gestational age with a Type 2 CSP. Sonographic evaluation revealed a low anterior gestational sac, empty uterine cavity and cervical canal, thin overlying myometrium, and no adnexal findings.

We will now demonstrate the five-step approach. In step one, we identify the anatomy. In step two, the vesicouterine peritoneum is dissected to reveal the pregnancy. In step three, haemostasis is ensured. In step four, we resect the pregnancy. And in step five we repair the caesarean scar defect.

Step one, identify the anatomy. Upon entry, we can see that our patient has adhesions of the bladder peritoneum anteriorly and laterally around the bulge of the CSP. A Valtchev uterine manipulator with a long insertion tip is carefully inserted under direct visualisation.

Step two, dissect the vesicouterine peritoneum. The peritoneum is carefully lifted and entry into the right paravesical space is planned. Bordered by the bladder, the pelvic sidewall and the uterine artery, the paravesical spaces are paired potential spaces within the pelvis. The umbilical ligament, as highlighted in green, divides the medial from lateral paravesical spaces. They largely lack blood vessels and nerves and are filled with loose areolar tissue, therefore providing a safe lateral border for our bladder dissection.

 The same technique is then applied on the left, once again while being mindful of the borders of the medial paravesical space. The bladder can then be lifted anteriorly and the vesicouterine peritoneum can be safely undermined and dissected away from the pregnancy.

Identification of the correct planes is essential here. Dissection too close to the bladder can result in a cystotomy, while too close to the pregnancy can result in entry into the placenta and haemorrhage. Cystosufflation can be used to delineate the bladder walls and to ensure that no injury has occurred. Having done so here, the vesicouterine peritoneum is safely dissected.

The exterior aspect of the caesarean scar pregnancy is now visible in its entirety. As you can see, there is now a significant distance between the bulge of the CSP and the bladder wall. Clearing this space will provide ample tissue and support for a multilayered reapproximation after the pregnancy and scar have been resected. The space is highlighted here in blue. The caesarean scar pregnancy is now visible in its entirety.

Step three, ensuring haemostasis. 20 units of vasopressin diluted in 100 cc of normal saline is then injected into the myometrium surrounding the pregnancy. While the maximum dose is unknown, using less than ten pressor units is generally felt to be safe.

Step four, resecting the pregnancy. As depicted in this illustration, the actual defect of most CSPs is quite small. However, the pregnancy and gestational sac balloon over the interior portion of this, creating the illusion of a larger defect. This shape resembles a mushroom, with the cap representing the external aspect of the pregnancy visible laparoscopically and the stalk representing the true underlying defect. Given this discrepancy, when resecting the pregnancy, cutting at an angle to the external edge of the defect is key, as this prevents resecting more than is necessary.

With this principle in mind, we begin our initial incision. Traction from the suction cautery demonstrates the funnelling of the pregnancy into the narrower defect below. Again, by visualising the mushroom analogy, we can see that we are beginning our resection at the outer aspect of the cap. However, the true defect or the stalk of the mushroom, lies below and is much narrower in its circumference.

With this in mind, we continue to resect along an angle towards the caesarean scar defect. This is performed using a release-and-push technique, as demonstrated here. Each individual layer of the defect is cut and subsequently pushed away to reveal the layer below. Here, we can see the edge of the true defect created below the pregnancy tissue in purple, again with the initial visible aspect outlined in blue.

Visible here is a steepening of the angle of the resection, representing the stalk of the mushroom. We have now reached the edge of the true caesarean scar defect. The gestational sac is then entered and smaller elements of products of conception are suctioned. The incision is then guided laterally using the advanced bipolar and cranially using the monopolar L-hook to allow for the same angle to transection. Once the serosal interface is reached the pregnancy is transected at its base.

With the resection complete, we can now inspect the site of the CSP. Once again, the true size of the defect is easily visible here, as circled in purple, while the edge of the pregnancy, which was initially visible, is circled in blue. Had we continued at a 90-degree angle from our initial incision, we would have resected a substantial amount of healthy myometrium, as highlighted here. An angled approach to resection is therefore essential to preserving uterine tissue.

Step five, the multilayered closure. Using a barbed monofilament suture, the angle of the defect is secured and we begin our two-layer closure. As we cinch the suture, we do so by applying tension towards the patient’s head to avoid undue stress upon the tissue. As the second layer comes together, note the reapproximation of tissue despite the wide initial defect and how the tension holds using the barbed suture. The uterus is now well approximated and no areas of dehiscence are seen.

In summary, this five-step approach provides a safe and haemostatic method for resection of caesarean scar ectopic pregnancies, while preserving ample myometrium with our angled resection for the subsequent repair.