3.1 Introduction
Müllerian anomalies are disorders of development of the female reproductive organs, specifically involving the uterus, cervix, and vagina. These anomalies may be asymptomatic, but some typically present during puberty or adolescence with symptoms such as pain or amenorrhea. Alternatively, müllerian anomalies may be detected during the reproductive years either incidentally on exam or imaging, or during an evaluation for infertility or reproductive loss. Surgical intervention is often performed either to treat symptoms or with the intention of decreasing the risk of potential adverse reproductive outcomes in future. This chapter will address the surgical treatment of uterine anomalies in the adult female.
3.2 Incidence
Müllerian anomalies are rare and the incidence is difficult to ascertain as it may vary depending on the specific anomaly and, in addition, many of these anomalies are asymptomatic. There are several classification systems to characterize müllerian anomalies [1–4]. There is no universally accepted classification system. All classification systems have advantages and disadvantages. The oldest and most widely used system is the American Fertility Society (now known as the American Society for Reproductive Medicine [ASRM]) classification (Figure 3.1) [1].
3.3 Reproductive Issues and Uterine Anomalies
Patients with uterine malformations have a higher incidence of abortions, preterm birth, and lower live birth rates [5]. The most common uterine malformations seen in reproductive age women include arcuate, septate, bicornuate, and didelphic uteri [5]. Arcuate uterus is felt, in some studies, to contribute to poor reproductive outcomes; however, in most studies it is believed to be clinically irrelevant and should not be corrected [6]. This discrepancy may be related to the classification of some septate uteri as arcuate as there is no universally accepted definition of these anomalies.
Traditionally, the poorest reproductive outcomes were seen with septate and bicornuate uteri [5] and these anomalies were corrected surgically by laparotomy. Treatment of septate uterus was revolutionalized with the advent of hysteroscopy and hysteroscopic septum resection, a much safer and less invasive surgical alternative when compared to an abdominal metroplasty. Advances in obstetrical and neonatal management of pregnancy with a bicornuate uterus have improved over time and as the methods to correct this anomaly are challenging, the surgery is not performed as frequently. Uterus didelphys, although associated with preterm delivery, is considered to be best managed by optimizing prenatal and neonatal care for the mother and baby. Surgical correction is rarely performed.
3.4 Septate Uterus
Septate uterus describes a uterus with a normal convex exterior and an endometrial cavity that is divided by fibromuscular tissue. This anomaly results from failure of resorption of the tissue connecting the paramesonephric (müllerian) ducts prior to the 20th week of fetal development. Its prevalence is difficult to ascertain as many of these anomalies are asymptomatic, but ranges vary between 1–2 per 1,000 and 15 per 1,000 [7]. Septate uterus may be viewed as part of a spectrum of the developmental uterine anomalies including arcuate, septate, bicornuate, and didelphys. A uterine septum may be further classified as being partial or complete. A partial septate uterus refers to a single convex external uterine fundus with a septum extending from the top of the endometrial cavity toward, but not including, the cervix. A complete septate uterus refers to a single outer uterine fundus with a septum that extends internally from the top on the endometrial cavity through the cervix, dividing both into two separate cavities, and is often associated with a longitudinal vaginal septum. Alternatively this anomaly may be associated with a duplicated cervix and longitudinal vaginal septum, similar to a uterus didelphys. Although traditionally believed to be a fibrous tissue, biopsy specimens and magnetic resonance imaging (MRI) imaging have shown that the septum is actually composed primarily of muscular tissue [8,9].
3.4.1 Diagnosis
As a septate uterus may be confused with a normal, arcuate, or bicornuate uterus or uterus didelphys, diagnostic evaluation should include an assessment of the outer uterine contour as well as the endometrial cavity so as to differentiate this anomaly from a bicornuate or didelphic uterus. The gold standard for the diagnosis of septate uterus had traditionally been laparoscopy with hysteroscopy. However, as radiologic techniques have improved ultrasound, 3-dimensional (3D) ultrasonography, with or without saline infusion, and MRI have largely replaced the more invasive surgical diagnostic methods [9–15]. 3-D ultrasonography alone [10,11] or in combination with saline infusion [11] has been shown to have 88% and 100% accuracy respectively when compared to laparoscopy or hysteroscopy in the diagnosis of septate uterus. MRI is also a valuable tool to diagnose septate uteri [9,13–15]. Hysteroscopy, when combined with imaging of the outer uterine contour, is also an effective and less invasive method. Hysterosalpingography or hysteroscopy alone are not adequate for the diagnosis of septate uterus as these techniques only assess the endometrial cavity.
3.4.2 Partial Septate Uterus
A partial septate uterus has a septum that divides the endometrial cavity but does not involve the cervix. The septum may vary in length, width, and vascularity. Although many classification systems exist, there is no single strict universally accepted definition of septate uterus. A standard definition would be helpful in many ways to differentiate septate from arcuate uterus, an anomaly that is not considered clinically relevant, to better characterize anomalies for research studies and also to help direct which patients would benefit from surgical correction. The widely used and accepted AFS classification [1], now referred to as the ASRM classification system, provides a pictorial depiction of the septate uterus with no strict parameters to differentiate it from an arcuate or bicornuate uterus. Proposed modifications to this classification suggest that a partial septum be defined as having the central point of the septum at an acute angle and the length to be greater than 1.5 cm, which differentiates it from an arcuate uterus, which has a broad obtuse fundal indentation and a depth between 1.0 and 1.5 cm [6,16,17]. In contrast, the European Society of Human Reproduction and Embryology and the European Society for Gynecological Endoscopy (ESHRE-ESGE) define a septate uterus as having an internal indentation extending >50% of the myometrial wall thickness [4] and there is no definition of arcuate uterus. When these two classification systems are compared, ESHRE-ESGE system classifies a uterus as septate rather than normal more frequently when the ASRM criteria are used (16.9% vs 6.1% respectively, RR 2.74, 95% CI 1.6–4.72, P<0.01) [18]. This difference in diagnosis leads to more potentially unnecessary surgeries being performed to correct a septum when the ESHRE-ESGE criteria are used.
3.4.3 Indication for Treatment
Many women with a septate uterus experience no adverse reproductive issues. However, septate uterus has been implicated in miscarriage, recurrent pregnancy loss, as well as preterm birth and other adverse pregnancy outcomes. These may be due to reduced sensitivity to steroids, defect of VEGF receptors, uncoordinated muscle contractions, and poor vascularization with poor placentation. A recent guideline by the ASRM evaluated and graded the literature regarding reproductive outcomes with, and following correction of, a uterine septum [6]. Overall, the studies assessing this topic are limited and comprised of generally small descriptive studies. Surgical correction of a uterine septum has been associated with a reduction in miscarriage rates and improvement in live birth rates in women with a history of miscarriage or recurrent pregnancy loss. Hysteroscopic septoplasty has also been show to improve clinical pregnancy rates in cases of otherwise unexplained infertility [6]. Thus, even in a patient with primary infertility, it may be reasonable to consider surgical correction given the potential to improve fertility and reduce poor reproductive outcomes with a simple procedure having minimal invasiveness and risk.
3.4.4 Treatment
Hysteroscopic techniques for correcting uterine septum have replaced the more invasive procedures such as the Jones wedge resection or Tompkins metroplasty.
3.4.4.1 Preoperative Considerations
Confirmation of septate configuration should be performed prior to surgery with imaging of external fundal contour as well as internal contour to avoid operating on a bicornuate uterus. If there are any concerns regarding the correct diagnosis, then intraoperative use of ultrasound or laparoscopy should be planned.
Surgery should be performed in the early follicular phase of the cycle or with medical suppression to achieve a thin endometrial lining for better visualization.
Preoperative hormonal manipulation to thin the endometrial lining may be achieved with combined oral contraceptive pills or progestin-only medication such as medroyprogesterone acetate or norethindrone acetate. However, these medications have not been systematically evaluated in the literature.
Preoperative treatment with danazol or GnRH agonists have been shown to have similar rates of bleeding, complications, adhesions, and residual septa [19]. These medications have a higher rate of side effects compared to combined hormonal contraceptives or progestins, and are no longer typically used for this indication.
3.4.4.2 Intraoperative Procedure
Hysteroscopic septoplasty divides a uterine septum using a variety of instruments including cold scissors, unipolar or bipolar cautery electrodes, or laser (see Video 3.1). No tissue is removed. Hysteroscopic distending media should be dictated by the technique or energy source with saline used for cold scissors or bipolar energy and nonconducting media such as glycine for unipolar cautery.
This procedure is typically performed in an operating room setting with sedation or general anesthesia. However, this may also be performed as an office hysteroscopic procedure with appropriate patient selection, surgeon experience, and equipment.
Dilation of the cervical canal may be necessary depending on the size of hysteroscope utilized. If a 5 mm scope is used, then dilation is often not necessary.
The hysteroscope is introduced through the cervical canal and advanced under direct visualization into both uterine horns, assessing the length and width of the septum as well as the presence of other pathology (Figure 3.2). Any adhesions, myomas, or polyps should be corrected during the same procedure.
Figure 3.2 Hysteroscopic view of a uterine septum.
There are different approaches to septum incision and the technique utilized depends on the size of the septum. Usually the septum is incised starting at the leading edge of the septum, typically just superior to the internal cervical os. The incision is then carried up toward the fundal region. As the septum gets wider toward the fundal region, the septum may be thinned by incising the lateral edges.
As septal tissue is predominantly fibrous, it retracts when incised and effectively disappears (Figure 3.3).
Figure 3.3 Hysteroscopic view of septum after incision. Note the septal tissue retracts and is no longer visible.
Care should be taken to have good visualization of the cavity at all times to ensure the line of incision is in the correct plane in the middle of the septum and not deviating anteriorly or posteriorly entering the myometrium and risking uterine perforation. Continually looking at the tubal ostia and visualizing the plane connecting them can be helpful.
If scissors are used, bleeding may occur, preventing good visualization. Cautery may be used to point cauterize the bleeding areas. Incising the septum with cautery reduces areas of bleeding, but cautery may cause damage beyond the incised area due to thermal spread.
Although there are several instruments available to surgically correct a uterine septum, one method has not been shown to be superior to another [6]. Scissors have the advantage of more control, lack of potential thermal damage, and the ability to uncover and detect and avoid blood vessels more easily. Cautery methods may be faster, but carry the risk of damage to the tissue beyond the area incised due to thermal spread. Reproductive outcomes following septum incision with available techniques are not significantly different although there are few randomized controlled trials comparing the methods.
It may be difficult to determine when the septum has been completely divided. The septum is traditionally incised until bleeding is encountered. However, this may not result in complete removal of the septum as, although mostly fibrous tissue, it may contain muscle and vascular tissue. Typically visual inspection is used to judge when the septum incision is complete. The hysteroscope should pass from one tubal ostia to the other without any intervening septal tissue visible. It may be difficult to accurately assess as the cornual regions of the endometrial cavity are often closer to the outer uterine contour than the fundal region, and if the septum is taken up too far, this may lead to incising and thinning the fundal myometrium. It is often best to err on the side of not incising the tissue as far up in the midline at the fundus to create a gentle curve to the fundal contour of the endometrial cavity. Alternative methods to assess adequate septal incision include simultaneous transabdominal ultrasonography or laparoscopy. Transabdominal ultrasonography is a noninvasive method that allows visualization of both the cavity and the outer uterine contour to assess when septal incision is complete and to avoid uterine perforation. Simultaneous laparoscopy has the advantage of allowing assessment and treatment of other pelvic pathologies but is more invasive than ultrasound and because it only provides visualization of the outer uterine contour, it is better suited to avoiding uterine fundal perforation rather than assessing whether the septal resection is adequate.
Care should be taken to avoid resection beyond the septal tissue. In addition to the obvious consequence of intraoperative uterine perforation, there is concern regarding delayed uterine perforation during subsequent pregnancy or delivery. Although rare, there have been 18 cases reported in the literature [7]. The risk of uterine rupture during a subsequent pregnancy is correlated with excessive septal incision, penetration of the myometrium, uterine wall perforation, and excessive use of cautery or laser energy during the procedure.
3.4.4.3 Postoperative Considerations
Postoperative adhesions are a concern following any hysteroscopic procedure, but are relatively rare following septum incision with an incidence of approximately 7% [20]. Methods proposed to decrease the risk of adhesions following septum incision include placement of an intrauterine balloon or device and postoperative estrogen therapy. These methods have not been adequately evaluated in the literature and no method has been proven to be superior to another or no treatment for this indication [6]. However, postoperative adhesion prevention strategies are often utilized.
Typically estrogen is used postoperatively for a period of 3–4 weeks. The rationale is to help proliferation of the endometrium over the recently incised septum. Doses used are typically higher than given to a postmenopausal female and include:
conjugated equine estrogens 0.625–1.25 mg orally twice daily;
17 β-estradiol 1–2 mg orally twice daily;
17 β-estradiol transdermal system 0.05–0.1 mg patch apply one to two patches, twice weekly.
Typically a progestin is given for the last 7–10 days of the estrogen therapy using either medroxy-progesterone acetate 5–10 mg, norethindrone acetate 1–5 mg, or oral micronized progesterone 100–200 mg.
An intrauterine balloon is often used to separate the walls of the endometrial cavity. A pediatric Foley catheter 8–12 French is ideal for this purpose with the balloon filled with 1.5–5 ml of sterile water. The Foley can be left in place for 2–7 days and then removed in the office. During this time antibiotics are usually prescribed to prevent infection.
Assessing for postoperative adhesions can be done by saline infusion ultrasonography (SIS), hysterosalpingography, or hysteroscopy. SIS is more sensitive than hysterosalpingography for detecting intrauterine adhesions. Hysteroscopy has the advantage of diagnosing and simultaneously treating any adhesions encountered and can be performed in an office setting with no anesthesia.
It is recommended to assess for the formation of postoperative adhesions and presence of residual septum following surgical correction, especially if the initial septum was large. This can be performed by 3-D ultrasound, SIS, hysterosalpingography, or hysteroscopy. 3-D ultrasonography can evaluate if there is a residual septal tissue present, but cannot assess for intrauterine adhesions. Hysteroscopy has the advantage of allowing for simultaneous surgical correction, but may be more invasive or involved, especially if performed in an operating room. The decision whether to correct a residual septum may be controversial. A large residual septum should be resected, especially in the setting of prior poor reproductive history. However, there are no strict guidelines regarding the definition of, or the clinical significance of, a small residual septum or whether it should undergo additional surgical intervention. The risks and benefits of an additional surgery should be considered in the context of the clinical situation of the individual patient.
There are a few studies evaluating the length of time from septum resection until pregnancy may be attempted. By 8 weeks postoperatively the uterine cavity has been shown to be morphologically normal and the endometrium normal as well [21]. In another study the endometrial cavity was shown to be healed in 100% of patients by 2 months postoperatively [22]. A study of 282 women who underwent in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) demonstrated that pregnancy and miscarriage rates were no different at <9, 10–16, or >17 weeks following septum resection [23]. While the uterine cavity appears to be healed by 2 months, there is no strict time frame recommended for when to allow a patient to conceive. Most advocate not less than 2 months following surgery.
A vaginal delivery is feasible in women who have undergone hysteroscopic uterine septum incision.
3.4.5 Complete Uterine Septum
A complete septum extends from the fundal region down through the cervix, creating a septated or duplicated cervix. Both may be seen in combination with a longitudinal vaginal septum. A complete septate uterus may be confused with a uterus didelphys, as both have a duplicated endometrial cavity, cervix, and a longitudinal vaginal septum. The difference is that the complete septate uterus had a single uterine fundus externally while with the didephys, the two hemi-uterine horns are distinct and often very disparate. Imaging is most helpful is distinguishing these anomalies, with 3-D ultrasound and MRI providing better evaluation [14,15].
When clinical outcomes are evaluated, complete septate uterus and partial septate uterus are associated with similar rates of first-trimester losses, second-trimester losses, and term deliveries [24]. As with a partial septate uterus, many women with a complete septate uterus have no reproductive issues. Indications for surgically correcting a complete septate uterus are similar to those for a partial septate uterus. The preoperative and postoperative considerations are similar for complete and partial septate uteri. The only difference is that a complete septate uterus is often associated with a longitudinal vaginal septum. Indications for removal of the vaginal septum are dyspareunia, desire to use tampons effectively, desire for a single vaginal canal, and for religious reasons to simplify detection of menstrual blood. In theory, it may improve fertility as the chance for conception may be reduced during cycles where intercourse occurs in the hemi-vagina contralateral to the ovulating ovary. Although a longitudinal vaginal septum is not a contraindication for a vaginal delivery, it increases the risk of complications.
3.4.5.1 Intraoperative Considerations
If there is a longitudinal vaginal septum, it is easier to resect the vaginal septum prior to resecting the uterine septum to allow better visualization and access to the cervices. Unlike the uterine septum, the vaginal septum needs to be removed to avoid redundant vaginal tissue that may prolapse out through the introitus. In addition, the vaginal septum is vascular. The septum may be removed by first separating the septum from the anterior vaginal wall starting at the introitus and progressing up to the level of the cervix. Techniques include successive bites with a clamp such as hemostat then cutting the vaginal tissue, or alternatively using a device such as a ligature, which cuts and cauterizes. The vaginal septum is then separated from the posterior vaginal wall in a similar fashion. Care should be taken to avoid damage to the adjacent rectum and bladder, which are often closer than they appear. The incisions can then be sutured in interrupted or running fashion to assure hemostasis.
There are two approaches for correcting a complete septate uterus. One is to preserve the cervical septum and just incise the uterine portion of the septum. The other is to divide both the cervical and uterine septae at the same time. The advantage of removing just the uterine septum and preserving the cervical septum is that cervical integrity is preserved. Cervical incompetence has been described in patients following unification of the cervical portion [25]. However, it can be a more challenging procedure. The advantage of resecting both cervical and uterine septa is that it is an easier and therefore quicker procedure. The decision is usually based on the thickness of the cervical septum. Thin septae are divided, whereas thick septae are left untreated.
The uterine septum can then be addressed. As for partial septum, the hysteroscope is passed through the cervical os, but both cervices need to be cannulated. The endometrial cavities are assessed as with a partial septate uterus. A tenaculum is placed on the anterior lip of both cervices. These hemi-cervices are typically small and tear easily.
If the cervical septum is to be preserved, a window is made in the uterine septum at the level of the internal cervical os and then the uterine septum is incised just as with the partial septum. Making a window from one endometrial canal to the other through the septum is the challenging part of the procedure. It is best to traverse the septum at the thinnest part, which is usually around the level of the internal cervical os. To identify the correct location and facilitate making the initial incision through the septum, a uterine sound, dilator, a Crile Bozeman, or other similar long-curved clamp placed in one uterine horn serves to tent the septum (Figure 3.4) [26,27]. With the hysteroscope in the other uterine horn, the tented septum can be easily visualized and an incision is made in the septum to communicate with the other side. An alternative technique is to place a pediatric Foley catheter in one uterine horn and distend it with saline while viewing with transabdominal ultrasonography. The relationship between the resectoscope and the septum is easy to see.
Figure 3.4 Technique for incision of complete uterine septum preserving the cervical septum. Instrument is placed in one cervical canal to tent septum to facilitate creating an opening in the septum from the other side [26].
Once there is a communication between the two cavities, the hysteroscopic fluid drains out through the cervix not occluded by the hysteroscope and uterine distention is lost. There are several options to occlude this outflow channel. As the external hemi-cervix is usually small, it can usually be clamped closed with an Allis or ring forceps. Alternatively a stitch can be placed through the external cervix to effectively occlude the outflow tract. Another option is to use a pediatric Foley balloon to occlude the cervical canal, especially if the Foley was used to facilitate creating an opening through the septum to join the two cavities.
Once a window is made in the septum, the hysteroscope is advanced through the window to evaluate both cavities and confirm correct location. The septum is then incised starting at the window just created incising the septum up to the fundus just as with the partial septum. The only difference is that the procedure is performed with the hysteroscope in one of the cervical canals so the approach is not directly in the midline.
If the cervical septum is resected at the same time as the uterine septum, the cervical septum may be cut using either heavy scissors or a monopolar electrode, or hysteroscopically using scissors or energy. The cervical septum is resected starting at the leading edge at the external cervical os and taken up through to the uterine septum and fundus utilizing the same techniques as with a partial septum. The external cervical os may be occluded using a clamp or suture if not sufficiently occluded with the hysteroscope.
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