Isthmocele incidence,causes,treatment and emergency
Isthmoceles have an incidence of 19-88% following cesarean section. This wide range is due to discrepancies in study technique, diagnostic criteria, and patient characteristics. Isthmocele is pocket like cesarean scar defect. This defect contains debris, mucus and blood which is responsible from symptoms like postmenstrual bleeding, dysmenorrhea, dyspareunia, infertility. It is often associated with postmenstrual abnormal uterine bleeding which is characterized by spotting after menstruation. uterine isthmocele has increasingly been included as part of the differential in women with a history of a cesarean section who present with postmenstrual bleeding, pelvic pain, or secondary infertility.
The defect appears as a fluid-filled, pouch-like abnormality in the anterior uterine wall at the site of a prior cesarean section. The best method for diagnosis is usually a saline-infused sonogram. It can be treated in various ways, depending on the patient’s symptoms and desire for future fertility. Although we have treated isthmoceles with hysteroscopic desiccation, or resection, our best success has occurred with laparoscopic resection and reapproximation of normal tissue in a small series of patients.
There is no standard definition of the defect that fully describes its size, depth, and other characteristics. Many words and phrases have been used to describe the defect: It is commonly referred to as an isthmocele, because of its usual location at the uterine isthmus, but others have referred to it as a cesarean scar defect or niche, as the defect may be found at the endocervical canal or in the lower uterine segment. In any case, while diagnoses appear to be increasing, the incidence of the defect is unknown.
More research on risk factors and treatment is needed, but the literature, as well as our own experience, has demonstrated that this treatable defect should be considered in the differential diagnosis for women who have undergone cesarean section and subsequently have abnormal bleeding or staining, pelvic pain, or secondary infertility, especially when fluid is clearly visible in the cesarean section defect.
An isthmocele forms in the first place, it is thought, after an incision, scar forms and causes retraction and dilation in the thinner, lower segment of the anterior wall and a thickening in the upper portion. There is a deficient scar, in other words, with disparate wound healing on the sides of the incision site.
Distortion and widening of the lower uterine segment and “free” red blood cells in endometrial stroma of the scar were the most frequently identified pathological changes, followed by fragmentation and breakdown of the endometrium of the scar, and iatrogenic adenomyosis.
Several small reports and case series published in the late 1990s offered additional support for a cause-and-effect correlation between cesarean scar defects and abnormal vaginal bleeding. Several years later, the link was strengthened as more investigators reported connections between the defects and various symptoms. These reports were followed by published comparisons of imaging techniques for the diagnosis of isthmoceles.
Diagnosis of the defects can be made with transvaginal ultrasound (TVUS), saline infused sonohysterogram (SIS), hysterosalpingogram, hysteroscopy, and magnetic resonance imaging (MRI). With any modality, imaging is best performed in the early proliferative phase, right after the menstrual cycle has ended.
Hysterosonogram evaluation of a uterine isthmocele.
Comparisons of unenhanced TVUS and SIS – both of which may be easily performed in the office and at a much lower cost than MRI – have shown the latter technique to be superior for evaluating isthmoceles. Distension of the endometrial cavity makes the borders of the defects easier to delineate, which enables detection of more subtle defects and improves our ability to measure the size of defects.
Another benefit of SIS over TVUS and hysterosalpingogram is that one can measure the thickness of the remaining myometrium overlying the isthmocele, which is especially important knowledge for patients considering another pregnancy. As a result, we have relied on this technique to diagnose every case within our practice. I will perform SIS in a patient who has a history of one or multiple cesarean sections and symptoms of abnormal bleeding, pelvic pain, or secondary infertility as part of the basic work-up.
The choice of treatment depends upon the patient’s symptoms and desire for future fertility, but it can include hormonal treatment, hysteroscopic resection, transvaginal repair, a laparoscopic or robot-assisted approach, and hysterectomy.
Little has been published on nonsurgical treatment, but this may be considered for patients whose primary symptoms are bleeding or pain and who desire the least invasive option. In a small observational study of women with an isthmocele and bleeding, symptoms were eliminated with several cycles of oral contraceptive pills .
Hysteroscopic Isthmocele correction.
Hysteroscopic isthmocele correction or resection are the surgical techniques most frequently described in the literature, but, as with other surgical approaches, studies are small. Hysteroscopic repair has typically involved the use of electrical energy to desiccate or cauterize abnormal tissue and eliminate the outpouching in which blood and fluid accumulate. Hysteroscopic resection is another technique that has also been championed.
However, for patients who desire future pregnancy, we do not recommend a hysteroscopic approach because it does not reinforce the often-thinning myometrium covering the defect. We are concerned that if this area is simply desiccated or resected, and not reapproximated, the patient will be at greater risk of pregnancy-related complications, including cesarean scar ectopic pregnancy with potential uterine dehiscence.
Laparoscopic Isthmocele correction:
When performing conventional laparoscopy, the isthmocele is excised with an ultrasonic curved blade. We use this instrument because it has no opposing arm and because it enables precise tissue dissection in multiple planes. With harmonic energy, we can limit tissue dessication and destruction, lowering the risk of future pregnancy-related complications. Monopolar scissors are best when a robotic approach is used.
Once the isthmocele is resected, the clean edges are sutured together in two layers. The first layer is sutured in an interrupted mattress-style fashion, to prevent tissue strangulation and necrosis. We use a monofilament nonbarbed delayed-absorbable 3-0 PDS suture – a choice that limits tissue trauma and postoperative inflammation.
Robot-assisted repair of isthmocele resection.
Sutures are initially placed at each angle with one or two sutures placed between. These sutures must be placed deep to close the bottom of the defect. A second layer of suture is then placed to imbricate over the initial layer of closure. We utilize 3-0 PDS in a running or mattress style, or a running 3-0 V-Loc suture. Our patients return after 1-3 months for a postoperative image, and are instructed to wait at least 3 months after surgery before attempting conception.