ABSTRACT
Abnormal uterine bleeding (AUB) from benign causes is experienced by approximately one in four premenopausal women. The prevalence increases with age and peaks just prior to menopause. 1 When menstrual blood loss (MBL) exceeds 80 ml, approximately two-thirds of women develop iron deficiency anemia. 2 In addition, AUB adversely affects women’s quality of life and can lead to significant utilization of healthcare resources. 3 In the past, menorrhagia was treated by dilatation and curettage (D&C) and/or hysterectomy. It has been shown that D&C has no therapeutic effect on menorrhagia. 1 Hysterectomy is a definitive therapy for menorrhagia, with high rates of patient satisfaction; however, it is associated with inflated rates of morbidity and costs. 1
Hysteroscopic endometrial ablation (HEA) was introduced in the 1980s as an alternative to hysterectomy in women with AUB of benign causes. Initially, there was rapid and wide interest in this procedure. This enthusiasm came to a halt, and even a decline in some countries (e.g. Australia), due to a realization that HEA required additional training and surgical expertise to avoid emergent procedure-related complications such as excessive fluid absorption, uterine perforations 4,5 and thermal injuries. 6 A prospective study (MISTLETOE) captured about 80% of HEA performed in the UK up to the mid 1990s. The efficacy of HEA and risk of complications were strongly related to skill and training of the surgeon. Severe complications, especially with use of the loop electrode, were more common in the first 100 cases of the surgeon. 7 To overcome these difficulties and concerns, a thermal balloon (ThermaChoice, Gynecare, Division of Ethicon, Somerville, NJ) invented by Neuwirth and Bolduc and described in 1994, was utilized that required skills similar to inserting an intrauterine contraceptive device (IUCD). 8
The invention consisted of a plastic catheter, 16 cm long × 3 mm in diameter, which was connected to a latex balloon on one side and to a control unit on the other. The latex balloon was designed to conform to the uterine cavity at an intraluminal pressure of approximately 70 mmHg. The distal end of the catheter formed the center axis of the balloon, inside of which there was a heating element and a thermistor surrounded by a perforated heat shield. The control unit monitored intra-balloon pressure, temperature, and duration of treatment. Initially, it was thought that the most appropriate intra-balloon pressure should be 70-80 mmHg. The initial six cases were conducted in the high altitude of Mexico City; thus, the temperatures within the balloon were kept below 100°C to avoid boiling of the liquid (5% dextrose in water) and any potential sequelae of steam formation. Subsequently, the control unit was programmed to provide a temperature range of 87 ± 5°C via a feedback thermistor/heating element software system.
