Britt Friberg
19
balloon catheter. The Cavaterm treatment is an outpa- tient procedure.
Operative
The first generation Cavaterm treatment was often per- formed under general anesthesia. The second generation,
Cavaterm plus , can be used with only paracervical block and intravenous sedation. The former is more often used for treatment with the first-generation Cavaterm catheter and the latter is usually used with the second-generation catheter, Cavaterm plus .
Surgery starts with measurement of cavity length and cervical dilatation to 6 mm. Curettage is performed if not done preoperatively. The length of the catheter is adjusted and the balloon purged. The balloon catheter is inserted to the fundus uteri. The balloon is filled with liquid, 5% glu- cose, until a pressure of 230–240 mmHg. Circulation is commenced and heating started to the target temperature, 78°C. Treatment time is 10 minutes at working tempera- ture. When treatment is finished, the balloon is deflated and the balloon catheter removed from the uterine cavity.
Postoperative
Patients usually need medication against pain in the first hours after surgery. They can return home as soon as the sedation during surgery has disappeared. Usually, there are no postoperative symptoms besides vaginal discharge.
IN VITRO AND IN VIVO STUDIES
The first experimental study was performed in 1992–93. 2 The Cavaterm treatment effect in vitro was studied in five extirpated uteri and in vivo in three patients treated pre- operatively just before hysterectomy. After 30 minutes heating of the endometrium to 58–65°C and a balloon pressure of 180 mmHg, histologic examination showed destruction of cells in the corpus uteri to a maximum depth of 8 mm. The 36 patients first treated were treated for 30 minutes, and thereafter treatment time was 15 minutes, as no major difference was seen in the outcome after 30 or 15 minutes’ treatment. In 2003, Hawe et al. 3 studied treatment result immediately post- and prehyster- ectomy. The serosal temperatures did not demonstrate any temperature rise above 44.1°C and macroscopic examination showed no thermal injury to the serosa.
Results suggested that treatment time could be reduced to 10 minutes.
Thermal conductivity and the water content of uter- ine tissue in vitro have been studied. 4 It was found that endometrial and myometrial tissues have similar thermal conductivities and water contents. It was also indicated that coagulation causes dehydration, resulting in a lower thermal conductivity. In another study 5 numerical calcu- lations provided a basis for estimation of the optimal intracavitary temperature and treatment time when per- forming thermal endometrial destruction by means of a balloon catheter.
Figure 19.1 The Cavaterm plus balloon catheter. (Reproduced with permission of Engineers & Doctors Wallsten Medical Group.)
Figure 19.2 The Cavaterm plus central unit and balloon catheter.
(Reproduced with permission of Engineers & Doctors Wallsten Medical Group.)
CLINICAL STUDIES
Published in 2000 were the first clinical results in 116 women followed up 10–46 months after treatment between 1993 and 1996. 6 The success rate was defined as amenorrhea, minimal or normal bleeding, at patients’
maximal bleeding assessment at final follow-up after treat- ment. The success rate was 94%, excluding women with preoperative intracavitary changes and pretreatment ultra- sonographically identified submucosal leiomyomas. Life- table analysis showed that the probability of assessing the treatment as ‘excellent’ or ‘good’ and avoiding hysterec- tomy over a 49-month period was 81%, and the prob- ability of avoiding hysterectomy over the same period was 85% when no exclusions were made.
The satisfaction rate and the effectiveness of transcer- vical hysteroscopic endometrial resection have been com- pared with thermal destruction of the endometrium by means of the Cavaterm balloon catheter. 7 The satisfaction rate was significantly higher, the operative time signifi- cantly shorter, and the intraoperative blood loss was sig- nificantly lower in the thermal destruction group.
Mettler evaluated 48-month follow-up in the treat- ment of menorrhagia and hypermenorrhea for patients treated with the Cavaterm technique. 8 In 60 women treated with this method, 58% reported amenorrhea, 33% hypomenorrhea, and 9% remained eumenorrheic.
The study included another 10 women with adenomyosis and uterine fibroids; i.e. women who before treatment were informed that the treatment might not be successful concerning diminished bleeding volume. Fifty percent of women treated in this group had to undergo hysterec- tomy. Another 50% were hypomenorrheic.
Cavaterm has been compared to another method for thermoablation (Menotreat) in a 6-month follow-up period. About 70% of the patients described the result of the treatment as ‘very good’. In this study, the two methods showed similar and good efficacy and patient acceptance. 9
Another study compares Cavaterm treatment to Nd:YAG (neodymium–yttrium aluminum garnet) laser. 10 The results with the Cavaterm balloon endometrial abla- tion system are as good as those obtained with the Nd:YAG laser in a study of 72 women in 12 months follow-up. The Cavaterm treatment resulted in a signifi- cant reduction in menstrual blood loss, high patient satis- faction, and improvement in the patient’s quality of life.
Abbott et al. in 2003 published a study comparing the Cavaterm and the NovaSure systems. 11 Both treatments are effective in reducing menstrual blood loss and achiev- ing high rates of patient satisfaction. Thirty-seven women were treated with the NovaSure system and 18 with the Cavaterm system.
A French study randomized women with menorrhagia to Cavaterm treatment or to hysteroscopic endometrial resection. Both treatments significantly reduced uterine bleeding. The 12-month decrease in the Cavaterm group was higher than in the resection group. Also, patients’ satisfaction was higher in the Cavaterm group. 12
Alaily, in a prospective study, showed a 24-month 90% satisfaction rate and 46% amenorrhea, 39% light periods, 4% normal, and 10% heavy periods. 13
A study of Cavaterm plus , the second-generation Cavaterm catheter, was performed by El-Toukhy et al. 14 The study included 220 patients. The mean follow-up time was 19 months (range 6–24 months). The amenorrhea–
hypomenorrhea rates at the various follow-up periods ranged between 74% and 93%. At the end of follow-up, 83% of patients were satisfied with the procedure.
In a review, microwave endometrial ablation and ther- mal balloon endometrial ablation vs transcervical resec- tion and rollerball ablation were compared as regards their effectiveness for treating heavy menstrual bleeding. 15 No significant differences were found in terms of amen- orrhea, bleeding patterns, premenstrual symptoms, patient satisfaction, or quality of life. Microwave endo- metrial ablation and thermal balloon endometrial abla- tion had significantly shorter operating and theater times than transcervical resection and rollerball ablation.
COMPLICATIONS
The Cavaterm system has been designed to be simple to use. The learning curve is very short. There is no risk of fluid absorption. When introducing the balloon catheter, there is a risk of making a false passage. If in doubt, an ultrasound or a hysteroscopy should be performed before starting the treatment. There is also a risk of uterine wall perforation. If this occurs, it should be impossible to reach the treatment pressure even when the balloon has been filled to the maximal volume of 30 ml.
In case of an uncontrolled rise in balloon pressure, the overpressure valve opens.
Thermal injuries should be avoided in the cervical area because of the insulation of the balloon shaft. No thermal effects on the outer uterine surface or on adjacent organs were found in experimental studies. 2 When treating a patient who has used gonadotropin-releasing hormone (GnRH) analogues or other hormonal pre-treatment, it is recommended to perform a preoperative ultrasound to measure the uterine wall thickness which has to be a minimum of 15 mm.
From a technological point of view, the method is safe, as the self-regulating heating elements make overheating
Obstetrics and Gynecology at Lund University in Swe- den, an estimation of costs of Cavaterm treatment and hysterectomy was carried out. Ahlgren and Friberg (pers comm) showed that costs for Cavaterm treatment were half those for hysterectomy. In those days, the treatment was performed in the operating theater. If carried out in the consultation room, costs ought to be even lower for the Cavaterm treatment. Studies comparing endometrial laser ablation, rollerball and endometrial resection to hys- terectomy have shown lower costs for the hysteroscopic techniques. 20 , 21
CONCLUSIONS
The Cavaterm plus thermal balloon ablation system is simple and easy to use. It is a reliable and safe system. The balloon length is adjustable, depending on the size of the uterine cavity. The fluid circulation system and the heat- ing element are unique. The technique is well suited for patients with intercurrent disease, who are at high risk at surgery. Success and the patient satisfaction rate are high.
The balloon endometrial techniques offer effective options in the surgical treatment of women with heavy menstrual bleeding. The endometrial ablation techniques offer an alternative to women with menorrhagia who prefer mini- mal operative and recovery time. The National Institute of Clinical Excellence (NICE) in the United Kingdom is recommending Cavaterm (and other second generation endometrial ablation devices) as the preferred surgical treatment for dysfunctional uterine bleeding (www.nice.
org.uk/TA078).
impossible and they are furthermore placed in the cathe- ter handle outside the body.
During the first 2–4 hours postoperatively, pain may be intense, and patients should be informed of this prior to treatment. Pain is successfully treated by prostaglandin synthetase inhibitors, which also can be given prior to treatment to reduce pain postoperatively. Occasionally, postoperative endometritis has been reported, and has been successfully treated with antibiotics. 6 , 16
Another uncommon complication reported after Cavaterm treatment is cervical stenosis, resulting in hematometra, 17 which has also been described after transcervical endometrial resection. 18 , 19
Since 1997, when Cavaterm was first marketed, six cases of uterine rupture and one case of bowel burn in connection with rupture have been reported to the manu- facturer (personal information from manufacturer Febru- ary 18th, 2007). Potential complications such as fluid overload and hemorrhage should be avoided and treat- ment time is short. This means that the Cavaterm treat- ment is well suited for patients with intercurrent disease such as cardiac problems, bleeding disorders, and anti- coagulation therapy.
COST
The standard end-user price for the disposable Cavaterm plus catheter is €585 exclusive of VAT. There are no studies published comparing the cost of the Cavaterm treatment with other treatments. In the late 1990s when the Cavaterm system was used in the Department of
References
1. Friberg B , Wallstén H , Henriksson P et al. A new, simple, safe, and efficient device for the treatment of menorrhagia. J Gynecol Tech 1996 ; 2 : 103 – 8 .
2. Friberg B , Persson BRR , Willén R , Ahlgren M . Endometrial destruction by hyperthermia – a possible treatment of menor- rhagia. An experimental study. Acta Obstet Gynecol Scand 1996 ; 75 : 330 – 5 .
3. Hawe J , Abbott J , Phillips G et al. In-vitro and in-vivo his- tochemical and thermal studies using a thermal balloon endo- metrial ablation system for varying treatment times. Hum Reprod 2003 ; 18 : 2603 – 7 .
4. Olsrud J , Friberg B , Ahlgren M , Persson BRR . Thermal con- ductivity of uterine tissue in vitro . Phys Med Biol 1998 ; 43 : 2397 – 406 .
5. Persson BRR , Friberg B , Olsrud J , Rioseco J , Ahlgren M . Numerical calculations of temperature distribution resulting from intracavitary heating of the uterus. Gynecol Endosc 1998 ; 7 : 203 – 9 .
6. Friberg B , Ahlgren M . Thermal balloon endometrial destruc- tion: the outcome of treatment of 117 women followed up for a maximum period of 4 years. Gynecol Endosc 2000 ; 9 : 389 – 95 . 7. Pellicano M , Guida M , Acunzo G et al. Hysteroscopic transcer- vical endometrial resection versus thermal destruction for men- orrhagia: a prospective randomized trial on satisfaction rate. Am J Obstet Gynecol 2002 ; 187 : 545 – 50 .
8. Mettler L . Long-term results in the treatment of menorrhagia and hypermenorrhea with a thermal balloon endometrial abla- tion technique. JSLS 2002 ; 6 : 305 – 9 .
9. Vihko KK , Raitala R , Taina E . Endometrial thermoablation for treatment of menorrhagia: comparison of two methods in out- patient setting. Acta Obstet Gynecol Scand 2003 ; 82 : 269 – 74 . 10. Hawe J , Abbott J , Hunter D , Phillips G , Garry R. A randomised
controlled trial comparing the Cavaterm endometrial ablation system with the Nd:YAG laser for the treatment of dysfunc- tional uterine bleeding. Br J Obstet Gynaecol 2003 ; 110 : 350 – 7 .
17. Friberg B , Joergensen C , Ahlgren M . Endometrial thermal coag- ulation – degree of uterine fibrosis predicts treatment outcome.
Gynecol Obstet Invest 1998 ; 45 : 54 – 7 .
18. Rådestad A , Svenberg T . [Hematometra. Complication after transervical resection of the endomentrium]. Läkartidningen 1995 ; 92 : 513 . [in Swedish]
19. Jacobs SA , Blumenthal NJ . Endometrial resection follow-up.
Late onset of pain and the effect of depot medroxyprogesterone acetate. Br J Obstet Gynaecol 1994 ; 101 : 605 – 9 .
20. Sculpher M . The cost-effectiveness of preference-based treat- ment allocation: the case of hysterectomy versus endometrial resection in the treatment of menorrhagia. Health Econ 1998 ; 7 : 129 – 42 .
21. Cameron IM , Mollison J , Pinion SB et al. A cost comparison of hysterectomy and hysteroscopic surgery for the treatment of menorrhagia. Eur J Obstet Gynecol Reprod Biol 1996 ; 70 : 87 – 92 .
11. Abbott J , Hawe J , Hunter D , Garry R. A double-blind random- ized trial comparing the Cavaterm™ and the NovaSure™
endometrial ablation systems for the treatment of dysfunctional uterine bleeding. Fertil Steril 2003 ; 80 : 203 – 8 .
12. Brun JL , Raynal J , Burlet G et al. Cavaterm thermal balloon endometrial ablation versus hysteroscopic endometrial resection to treat menorrhagia: the French multicenter, randomized study.
J Minim Invasive Gynecol 2006 ; 13 : 424 – 30 .
13. Alaily AB , Auld BJ , Diab Y . Endometrial ablation with the Cava- term™ thermal balloon. J Obstet Gynecol 2003 ; 23 : 51 – 4 . 14. El-Toukhy T , Chandakas S , Grigoriadis T , Hill N , Erian J .
Outcome of the first 220 cases of endometrial balloon ablation using CavatermTM plus . J Obstet Gynaecol 2004 ; 24 : 680 – 3 . 15. Garside R , Stein K , Wyatt K , Round A . Microwave and thermal
balloon ablation for heavy menstrual bleeding: a systematic review. Br J Obstet Gynaecol 2005 ; 112 : 12 – 23 .
16. Hawe JA , Phillips AG , Erian J , Garry R . Cavaterm™ thermal balloon ablation for the treatment of menorrhagia. Br J Obstet Gynaecol 1999 ; 105 : 1143 – 8 .
148 INTRODUCTION
Abnormal uterine bleeding (AUB) from benign causes effects 20–25% of premenopausal women. 1 It is one of the most common presenting symptoms for gynecology patients, accounting for 15% of gynecology clinic patients, and is the major indication for 25% of gynecologic oper- ations. 2 Menstrual disorders is listed as the second most common indication for hysterectomy (15–20%) and, together with uterine fibroids, accounts for up to 70% of all hysterectomies. 3–6
First-line treatment for dysfunctional uterine bleeding (DUB) consists of medical management with non-steroidal anti-inflammatory drugs (NSAIDs), 2 , 7–9 antifibrinolytics, 9–11 progestins, 12–14 combined estrogens and progestins, 15 , 16 androgens, 17 or antiprogestational agents. 18 If a patient fails or has a contraindication to medical therapy, surgical therapy is utilized. Up until the 1980s, dilatation and curettage (D&C) had been widely used as a treatment for DUB. However, D&C has since been shown to have diag- nostic value and no therapeutic effect on DUB. Hysterec- tomy was the definitive surgical standard for the treatment of menorrhagia and was associated with a high rate of satisfaction. Hysterectomy can be associated with many potential adverse events, such as death, significant blood loss requiring transfusion, deep venous thrombosis, pul- monary embolism or infarction, myocardial infarction, abscess formation, sepsis, injury to bowel, bladder, or major blood vessels, longer postoperative recovery times, potentially long-term implications, 19–24 and high direct and indirect costs. 25 – 27 Over the last few decades, the trend in gynecology has been towards minimally invasive thera- pies for the treatment of common gynecologic conditions such as menorrhagia. Endometrial ablation has been devel- oped as an alternative to hysterectomy for the manage- ment of menorrhagia. The gold standard for ablation of the endometrium is hysteroscopically directed rollerball ablation or resection. It is safe, effective, and durable but requires significant technical skill. In addition, endome- trial ablation is more cost-effective than hysterectomy as therapy for menorrhagia. 25–27 Global endometrial ablation
or second-generation endometrial ablation technologies (SEATs) were introduced as equally safe and effective as hysteroscopically directed ablation, but are less skill- intensive. 28 –30