Uterine Fibroid Embolisation

3 July 2015


By Dr SEE Teik Choon, FRCS, FRCR, Consultant Interventional Radiologist, Cambridge, UK

Uterine Fibroids
, or uterine myomas (short for leiomyoma), affect more than 30% of women. The terms fibroid and myoma are used interchangeably. Most fibroids do not cause symptoms, and do not require treatment. Fibroids may require treatment in the following circumstances:
 

1. Fibroids are growing large enough to cause pressure on other organs, such as the bladder.

2. Fibroids are growing rapidly

3. Fibroids are causing abnormal bleeding

4. Fibroids are causing problems with fertility


Types of Fibroids


Fibroids are classified by their location which effects the symptoms they may cause and how they can be treated. Fibroids that are inside the cavity of the uterus will usually cause bleeding between periods (metrorrhagia) and often cause severe cramping. Fortunately, these fibroids can usually be easily removed by a method called “hysteroscopic resection”. This can be done through the cervix without the need for an incision. Submucous myomas are partially in the cavity and partially in the wall of the uterus. They too can cause heavy menstrual periods (menorrhagia) as well as bleeding between periods. Some of these can also be removed by hysteroscopic resection.

Intramural myomas are in the wall of the uterus, and can range in size from microscopic to larger than a grapefruit. Many of these do not cause problems unless they become quite large. There are a number of alternatives for treating these, but often they do not need any treatment at all. Subserous myomas are on the outside wall of the uterus, and may even be connected to the uterus by a stalk (pedunculated myoma). These do not need treatment unless they grow large, but those on a stalk can twist and cause pain. This type of fibroid is the easiest to remove by laparoscopy.

Diagnosis of Fibroids


Fibroids may be felt during a pelvic exam, but many times, those that are causing symptoms may be missed if the examiner relies just on the examination. Also, other conditions such as adenomyosis or ovarian cysts may be mistaken for fibroids. For this reason, an ultrasound examination should be done at the time of the first visit when a woman has symptoms of abnormal bleeding or cramping, or if there is an abnormality on examination. Vaginal probe (transvaginal route) ultrasound only takes a few minutes to do, is not uncomfortable, and rapidly provides invaluable information if the examiner is experienced in looking at uterine abnormalities. It is possible to fill the uterus with a liquid during the ultrasound (saline enhanced sonography or sonohysterogram). While this will often provide additional information to the regular ultrasound, I usually learn much more by looking inside the uterus with a little telescope. This exam, called hysteroscopy, is usually a quick office procedure, that allows directly looking inside the uterus. Click here to learn more about hysteroscopy.

One of the most common conditions confused with fibroids is adenomyosis. In adenomyosis the lining of the uterus infiltrates the wall of the uterus, causing the wall to thicken and the uterus to enlarge. On ultrasound examination this will often appear as diffuse thickening of the wall, while fibroids are seen as round areas with a discrete border. Adenomyosis is usually a diffuse process, and rarely can be removed without taking out the uterus. Since fibroids can be removed, it is important to differentiate between the two conditions before planning treatment. It is also common to have some adenomyosis in addition to fibroids.

Magnetic Resonance Imaging (MRI) scans also provide an excellent picture of the uterus. Usually the cost of the exam is not justified, as all of the information needed to plan treatment (or not to treat) can be obtained by other methods.

Treatment of Fibroids


Uterine fibroids are common in women of reproductive age and the main issues are fertility potential and the management of the symptoms. Uterine fibroids cause a variety of symptoms with different levels of severity. The guidelines issued by the American College of Obstetricians and Gynecologists (ACOG) suggest that asymptomatic women should be managed expectantly, while for those with mild symptoms it would be desirable for intervention to be as close to the desired pregnancy as practical given the inherent risk of recurrence (1). Treatment for fibroids that cause severe bulk related symptoms or/and menorrhagia are usually indicated. Optimal treatment modality should be based on symptoms, size and site of fibroids, fertility needs and the overall risks and benefits of the treatment. Traditionally this would usually involve hysteroscopic resection or a hysterectomy.

The first report of uterine artery embolisation (UAE) for fibroids was published in 1995 (2). Subsequently there has been an enormous interest in this treatment modality worldwide. In the UK, UAE can now be routinely offered as a primary treatment for uterine fibroids outside of clinical trials, although it is recommended that all procedures are registered. The main objective of UAE is elimination of the symptoms with fibroid shrinkage as an additional advantage. The results of UAE are encouraging with 58% reduction of fibroid volume after 6 months and improved symptoms in 91% of women (3). The majority of shrinkage occurs within a 6 month period but some further reduction in size occurs between 6 and 12 months (4). In a review of the published data involving 60-305 patients (5), symptomatic improvement rate was between 80-92% and hysterectomy rate of 0% and 2%. This is a good outcome compared to the satisfaction rates from hysterectomy which was reported in excess of 90% (6). Interestingly, improvement in menorrhagia was unrelated to initial fibroid size or amount of fibroid shrinkage (7).

Most centres would admit the patient for overnight stay mainly for pain control but UAE can be performed as outpatient basis, provided that patients are appropriately advised and medical attention is available when required. Imaging assessment of the fibroids can be performed with ultrasound or MRI. Volume measurements are obtained pre and post UAE. Patients are counselled prior to the procedure. Prophylactic antibiotics are indicated.

UAE is mainly performed by interventional radiologists who are familiar with the techniques of vascular access, catheter manipulation as well as embolisation. The procedure is performed under local anaesthesia, intravenous analgesia, and sedation if required. The right common femoral artery is punctured and a catheter is used to negotiate the way to the arteries supplying the uterus. Spasm may occur and this may result in inadequate embolisation. This may be relieved with glycerate trinitrate or the procedure may be stopped for a few minutes. Once the uterine artery has been catheterised, embolisation can then be performed. Both uterine arteries (there are 2 main supplies to the uterus) should be cannulated and embolisation carried out.

As the UAE is carried under the guidance of xrays (real time fluoroscopy), it is important to avoid excessive screening and image acquisition in order to avoid extensive ovarian radiation exposure. There are techniques to keep radiation to the minimum yet allowing the procedure to be guided safely and successfully. Radiologists are trained in this area of radiation protection and with further training in interventional radiology; they are best qualified to ensure the minimum exposure to the patient and themselves.

The embolic materials commonly used for UAE are non-spherical polyvinyl alcohol (PVA) particles, trisacryl gelatine microspheres (eg. embospheres), and gelatine sponge. Embolisation material should be injected under free flow condition and great care must be taken that they do not “clog” the catheters or the wrong blood vessels.

Complications of the procedure include groin haematoma (blue black bump due to blood leaking from the puncture wound into the soft tissues around the blood vessel) and contrast medium reaction which are intrinsic to all vascular interventional procedure. Non-target-organ embolisation is uncommon and this is can be minimised by injecting the embolic agent carefully according to flow.

Post-embolisation syndrome is common and all patients should be warned regarding nausea, vomiting, low grade fever, malaise, and pain. Symptoms can vary in intensity and may last 2 to 7 days. Pain should be adequately controlled with intravenous analgesia (pain-killers) during the procedure and possibly for a further 24 hours before switching to oral analgesia. Post embolisation syndrome can be difficult to differentiate from infection which is serious and should be considered if there is persistent high temperature and raised white cell count.

Infection rate of 1-2% has been reported (5) and this may occur even months after the procedure. It is more common with larger fibroids and may necessitate a hysterectomy. Fibroids extrusion occurs in about 10% of cases with small fibroids being expelled spontaneously while larger one may necessitate a minor surgical procedure for removal, especially if impacted at the cervix (5). Benign chronic discharge is not uncommon affecting up to 7% of patients (8). It is more likely to occur when the fibroids are large.

Amenorrhea (absence of menses) is highly age-dependent. The incidence of ovarian failure is lower than 5% in women under the age of 45 (9) but it has been estimated at 43% in women older than 45 years (10). As yet there is no established data on the effect of UAE on pregnancy and fertility.

The location of the fibroids may also have an impact on the success or the risk of the procedure. There is a general consensus that pedunculated and mainly subserosal fibroids do not respond well to fibroid embolisation and that the procedure is more effective for interstitial and submucosal fibroids. There is also the concern of totally necrosing (killing off by cutting off the blood supply) the pedunculated fibroid with consequent infection. In a patient with multiple fibroids of different locations, resection of the pedunculated subserosal fibroid combined with UAE of other fibroids should be considered. Infective complications are potentially more likely with submucosal fibroids where exposure to intracavitary (within the cavity of the uterus) pathogens may occur (11).

There is no doubt that UAE is increasingly performed worldwide. It is minimally invasive compared to surgical methods such as myomectomy, hysterectomy or keyhole surgery such as laparoscopic myolysis. The evidence so far suggests that it is effective to control bulk-related symptoms and menorrhagia with acceptable risk but longer term data is required to evaluate its effect on fertility.

REFERENCES:

ACOG practice bulletin : surgical alternatives to hysterectomy in the management of leiomyomas. Int J Gynaecol Obstet 2001 ; 73: 285-294.

Ravina JH, Herbreteau D, Ciraru-Vigneron N et al. Arterial embolisation to treat uterine myomata. Lancet 1995; 346: 671-672.

Watson GM, Walker WJ. Uterine artery embolisation for the treatment of symptomatic fibroids in 114 women: reduction in size of the fibroids and women’s view of the success of the treatment. Br J Obstet Gynaecol 2002; 109: 129-135.

Walker W, Green A, Sutton C. Bilateral uterine artery embolization for myomata: results, complications and failures. Min Invas Ther & Allied Technol 1999; 8:449-454.

Belli AM. Uterine artery embolization for the treatment of fibroids. CME Radiol 2002; 3 (1): 20-25.

Dwyer N, Hutton J, Stirrat GM. Randomised control trial comparing endometrial resection with abdominal hysterectomy for the surgical treatment of menorrhagia. Br J Obstet Gynaecol 1993; 100: 237-243.

Pron G, Bennett J, Common A, et al. The Ontario Uterine Fibroid Embolization Trial. Part 2. Uterine fibroid reduction and symptom relief after uterine artery embolization for fibroids. Fertil Steril 2003; 79: 120-7.

Reidy JF, Bradley EA, Forman RG et al. Uterine artery embolization. Results in 234 patients [abstract]. Minim Invasive Ther Allied Technol 1999; 8 (Suppl): 26.

Walker WJ, Pelage JP, Sutton C. Fibroid embolization. Clin Radiol. 2002 May;57(5):325-31. Review.

Chrisman HB, Saker MB, Ryu RK et al. The impact of uterine fibroid embolization on resumption of menses and ovarian function. J Vasc Interv Radiol. 2000 Jun;11(6):699-703

Pelage JP, Le Dref O, Soyer P et al. Fibroid-related menorrhagia: treatment with superselective embolization of the uterine arteries and mid-term follow-up. Radiology 2000; 215:428-431

Royal College of O & G Uterine Fibroid Embolisation Guidelines 2013 – please click here