Successful microwave endometrial ablation in a uterus enlarged by adenomyosis.

Adenomyosis can cause severe menorrhagia, which is a common indicator of the need for hysterectomy. None of the ablative techniques developed over the last two decades are of use in treating menorrhagia in a uterus enlarged by deep adenomyosis. Using a curved microwave applicator specifically developed for enlarged uterine cavities, microwave endometrial ablation at a frequency of 2.45 GHz was successfully applied in the treatment of menorrhagia in a patient with adenomyosis and an enlarged uterine cavity 12 cm in length. Two weeks after the operation, the patient experienced a menstrual period of ten days with no flooding. Menstrual duration gradually decreased to six days over the following six months. The quality of life score recovered to within the normal range six months after the operation. The post-operative sub-endometrial low signal intensity zone on the T2-weighted magnetic resonance images, which corresponds to the region of necrotic tissue, vanished 12 months after the operation. Although microwave endometrial ablation using the curved applicator could not treat bleeding from deep adenomyosis lesions, it improved menorrhagia in the uterus, which would conventionally require a hysterectomy. ,FZ
XPSETMicrowave endometrial ablation; Adenomyosis; Menorrhagia

Adenomyosis is a tumor-like lesion that causes a disabling condition associated with menorrhalgia and menorrhagia. Since no effective hormone therapy is known, hysterectomy is indicated in many cases to relieve the refractory symptoms. For menorrhagia, endometrial ablation is an alternative to hysterectomy, however none of the ablative techniques developed over the last two decades have been of use in treating menorrhagia in a uterus enlarged by adenomyosis, because they cannot treat adenomyosis lesions located deep in the myometrium 1). In addition, an enlarged uterus is one of the contraindications for conventional endometrial ablation 2). Recently, the applicability of microwave endometrial ablation (MEA) at a frequency of 2.45 GHz -47 - using a curved microwave applicator was reported for patients with an enlarged uterus and distorted uterine cavity more than 12 cm in length 3). In addition, by selecting the microwave power and irradiation time the depth of microwave thermal necrosis is adjustable. Therefore, MEA at 2.45 GHz is a candidate for the treatment of menorrhagia in an enlarged uterus as a

of adenomyosis. Because necrotic tissue often maintains its microscopic structure for more than three months without signs of necrosis, microwave thermal necrosis is often referred to as coagulation 4). With the use of magnetic resonance imaging (MRI), this study reports a case of adenomyosis with an enlarged uterine cavity that was successfully treated by MEA. Case Report The patient, who was a 46-year-old bipara and head of a company, had been suffering from menorrhagia due to adenomyosis since the age of 35. Menorrhalgia was not severe. As her Kanaoka et al -48 - Figure 1. (a), T2-weighted MR image before the MEA (sagittal section). The endometrium is shown as the high intensity area (arrow). (b), T2-weighted MR image one month after the MEA (sagittal section). The uterine cavity is shown as a thin line (thin arrow) with high intensity, which is surrounded by a low intensity area (thick arrow). (c), T2-weighted MR image three months after the MEA (sagittal section). The uterine cavity is unclear and the low intensity area (arrow) is smaller than in Figure 1b. (d), Gd-enhanced T1-weighted MR image three months after the MEA (sagittal section). The contrast medium shows that the uterine cavity is surrounded by avascular tissue, which is enclosed by a thin high intensity line (arrow). (e), T2-weighted MR image 12 months after the MEA (sagittal section). The uterine cavity was depicted as a high intensity area (long arrow), which suggests that the endometrial tissue is regrowing. The short arrow shows a new myoma node at the anterior wall of the cervix. (f), Gd-enhanced T1-weighted MR image 12 months after the MEA (sagittal section). The avascular area three months after the MEA is not depicted. hemoglobin level was found to be 5.8 g/dL, her attendant doctor administered iron supplements for two years, however, the menorrhagia continued to worsen over this period as her uterus gradually grew. Due to flooding, the patient was unable to work or go out for the first 3 days of menstrual bleeding, which brought about palpitations and general fatigue due to severe anemia. The duration of bleeding was 12 days. The patient was therefore referred to our hospital. On admission, the patient’s hemoglobin level was 8.3 g/dL just before her next menstruation period. Bimanual examination revealed that her uterus was larger than a newborn’s head in size. MRI analysis revealed thickened uterine walls due to adenomyosis and the uterine cavity was 12 cm in length (Fig. 1a). Endometrial malignant diseases were ruled out by an endometrial biopsy. The patient’s status was evaluated by completion of a questionnaire for menorrhagia (Table 1) 5). She scored 13 points, which showed a deteriorated quality of life (QOL). Since the patient did not want to interrupt her work schedule with a long hospital admission, she selected MEA as an alternative to hysterectomy after informed consent. A microwave tissue coagulator (Microtaze OT 110M, Azwell Inc. Osaka, Japan) and curved microwave applicator, which was developed by the authors specifically for MEA in an enlarged uterus with a distorted uterine cavity, were employed (Fig. 2). Using transabdominal ultrasound, the applicator can reach the uterotubal area and fundus, which tend to remain untreated when using the straight intra-uterine instruments available for conventional endometrial ablation when the uterine cavity is enlarged and distorted. The patient did not undergo any endometrial thinning by administration of a gonadotropin releasing hormone agonist or danazol. Microwave coagulation was performed by pressing the tip of the applicator to the uterine wall to coagulate the basal layer of the endometrium and adjacent myometrium as deeply as possible. Nine coagulation sites including both uterotubal areas and the fundus were selected under ultrasonography so that no untreated endometrium remained. The microwave output at the applicator tip and the duration were 40 W and 50 seconds, respectively, for each MEA for Adenomyosis -49 - Figure 2. The curved microwave applicator, which is 4 mm in diameter. coagulation site, except for two sites on the midline of the uterine cavity where the duration increased two-fold. It took 11 minutes to perform the MEA uneventfully under general anesthesia using a laryngeal tube. A hysteroscopic examination performed following completion of the MEA revealed that the uterine cavity was covered with thin yellowish tissue and no intact endometrium was observed. Two weeks after the MEA, the patient experienced menstrual bleeding lasting for ten days without flooding. Menstruation duration gradually decreased to six days over the following six months. Six months after the MEA, the patient’s QOL score decreased to 3 points (Table 1) and she was categorized into the group of healthy women. The patient was satisfied with the results. Magnetic resonance imaging was performed before, one month, three months and twelve months after the MEA. The endometrial lining of the uterine cavity and the junctional zone in the myometrium were not depicted by the T2-weighted MRI taken one month after the MEA (Fig. 1b), although the uterine cavity was conserved and sounding was possible. Three months after the MEA, the low intensity area became smaller than it was one month after the operation (Fig. 1c). A Gd-enhanced T1-weighted MRI revealed that an avascular area 7-9 mm in depth entirely surrounded the uterine cavity (Fig. 1d). Twelve months after the MEA, the endometrial lining was depicted on a T2-weighted image (Fig. 1e). The avascular area was not identified by an enhanced MRI study (Fig. 1f).

In general, the MEA induces thermal necrosis in the endometrium and myometrium within 7 mm of the surface of the uterine cavity. This necrotic tissue is replaced by granulation tissue after several months and finally the uterine cavity is obliterated with fibrous tissue 5). At the standard microwave setting MEAs cannot fully treat adenomyosis that are thicker than 7 mm for dysfunctional uterine bleeding. Therefore, in this study the applicator was held to the uterine wall with pressure so its tip was as close as possible to the myometrium ensuring that Kanaoka et al -50 - Menorrhagia Yes/No Score Before Six months Dysmenorrhea If yes 2 0 0 Cycle length If ʼ 28 0 0 0 If 24-27 1 If ʻ 24 2 Heavy days Score 1 each day 5 0 Sanitary wear If double 2 2 0 Frequency of changing ʻ 2 h 1 1 1 ʻ 1 h 2 Clots If yes 1 1 1 Flooding If yes 1 1 0 Housebound/ If yes 2 2 0 time off work Duration of problem If ʼ 5 years 1 1 (pre-op) If any bleeding If yes 1 1 (post-op) 2 Total 13 3 Table 1. Menstrual score before and six months after the MEA each coagulation site included as many adenomyosis lesions as possible. One month later, MRI analysis revealed that the eutopic endometrium was completely coagulated. Hysteroscopy just after the MEA is convenient for detecting untreated myometrium, although it can only offer information about the surface of the endometrium. On the other hand, T2-weighted MRIs can depict the endometrium and junctional zone, but enhanced MRIs are needed to assess the coagulated area more clearly 6). In this case, the coagulated area was recognized on Gd-enhanced T1-weighted images. The coagulated area surrounding the uterine cavity was enclosed by a thin line of which the signal intensity was enhanced by the contrast medium one month and three months later. This line seems to correspond to the granulation tissue growing between the living tissue and coagulated tissue. One month after MEA, the eutopic endometrium was not depictable, although menstruation did occur. The persisting menstruation seems therefore to come from an adenomyosis lesion. Bleeding from a deep adenomyosis lesion through long thin canals might cause a prolonged period following an MEA. Flooding on days 1 to 3, which was relieved after the MEA, seemed to be mainly caused by the eutopic endometrium. As previously reported, menorrhagia tends to persist after endometrial ablation in deep adenomyosis cases. The present case demonstrates that the glands of adenomyosis lesions maintain their connection with the uterine cavity. Microwaves at 2.45 GHz supplied by the curved applicator could improve menorrhagia in a uterus enlarged by adenomyosis, but it is difficult to coagulate all the adenomyosis lesions at the standard setting of microwaves for MEA. Based on the results of an analysis using the finite element method of the electric field and temperature distribution in the myometrium around the applicator tip (unpublished data), the microwave duration was doubled for two coagulation sites, which induced a 30% increase in the depth of the coagulation area. To treat adenomyosis tissues deep in the myometrium, it is conceivable to coagulate the adenomyosis lesions using a thin needle type microwave electrode 7) introduced though a transcervical puncture. Addition of in situ coagulation within an adenomyosis lesion might be effective, as well as coagulation from the inner surface with an increased output and longer duration of the microwaves.

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