Commentary

RFVTA system offers alternative to myomectomy


 

References

Uterine myomas cause heavy menstrual bleeding and other clinically significant symptoms in 35%-50% of affected women and have been shown to be the leading indication for hysterectomy in the United States among women aged 35-54 years.

Research has shown that a significant number of women who undergo hysterectomy for treatment of fibroids later regret the loss of their uterus and have other concerns and complications. Other options for therapy include various pharmacologic treatments, a progestin-releasing intrauterine device, uterine artery embolization, endometrial ablation, MRI-guided focused ultrasound surgery, and myomectomy performed laparoscopically, robotically, or hysteroscopically.

Myomectomy seems largely to preserve fertility, but rates of recurrence and additional procedures for bleeding and myoma symptoms are still high – upward of 30% in some studies. Overall, we need other more efficacious and minimally invasive options.

Dr. Jay M. Berman

Dr. Jay M. Berman

Radiofrequency volumetric thermal ablation (RFVTA) achieved through the Acessa System (Halt Medical) has been the newest addition to our armamentarium for treatment of symptomatic fibroids. It is suitable for every type of fibroid except for type 0 pedunculated intracavitary fibroids and type 7 pedunculated subserosal fibroids, which is significant because deep intramural fibroids have been difficult to target and treat by other methods.

Three-year outcome data show sustained improvements in fibroid symptoms and quality of life, with an incidence of recurrences and additional procedures – approximately 11% – that appears to be substantially lower than for other uterine-sparing fibroid treatments. In addition, while the technology is not indicated for women seeking future childbearing, successful pregnancies are being reported, suggesting that full-term pregnancies – and vaginal delivery in some cases – may be possible after RFVTA.

The principles

Radiofrequency ablation has been used for years in the treatment of liver and kidney tumors. The basic concept is that volumetric thermal ablation results in coagulative necrosis.

The Acessa System, approved by the Food and Drug Administration in late 2012, was designed to treat fibroids, which have much firmer tissue than the tissues being targeted in other radiofrequency ablation procedures. It uses a specially designed intrauterine ultrasound probe and radiofrequency probe, and it combines three fundamental gynecologic skills: Laparoscopy using two trocars and requiring no special suturing skills; ultrasound using a laparoscopic ultrasound probe to scan and manipulate; and probe placement under laparoscopic ultrasound guidance.

Specifically, the system allows for percutaneous, laparoscopic ultrasound–guided radiofrequency ablation of fibroids with a disposable 3.4-mm handpiece coupled to a dual-function radiofrequency generator. The handpiece contains a retractable array of electrodes, so that the fibroid may be ablated with one electrode or with the deployed electrode array.

The generator controls and monitors the ablation with real-time feedback from thermocouples. It monitors and displays the temperature at each needle tip, the average temperature of the array, and the return temperatures on two dispersive electrode pads that are placed on the anterior thighs. The electrode pads are designed to reduce the incidence of pad burns, which are a complication with other radiofrequency ablation devices. The system will automatically stop treatment if either of the pad thermocouples registers a skin temperature greater than 40° C ( JSLS. 2014 Apr-Jun;18[2]:182-90 ).

The outcomes

Laparoscopic ultrasound–guided RFVTA has been studied in five prospective trials, including one multicenter international trial of 135 premenopausal women – the pivotal trial for FDA clearance – in which 104 women were followed for 3 years and found to have prolonged symptom relief and improved quality of life.

At baseline, the women had symptomatic uterine myomas and moderate to severe heavy menstrual bleeding measured by alkaline hematin analysis of returned sanitary products. Their mean symptom severity scores on the Uterine Fibroid Symptom and Quality-of-Life Questionnaire (UFS-QOL) decreased significantly from baseline to 3 months and changed little after that, for a total change of –32.6 over the study period.

The cumulative repeat intervention rate at 3 years was 11%, with 14 of the 135 participants having repeat interventions to treat bleeding and myoma symptoms. Seven of these women were found to have adenomyosis ( J Minim Invasive Gynecol. 2014 Sep-Oct;21[5]:767-74 ).

The surprisingly low reintervention rates may stem from the benefits of direct contact imaging of the uterus. A comparison of images from the pivotal trial has shown that intraoperative ultrasound detected more than twice as many fibroids as did preoperative transvaginal ultrasound, and about one-third more than preoperative MRIs ( J Minim Invasive Gynecol. 2013 Nov-Dec;20[6]:770-4 ).

Interestingly, four women became pregnant over the study’s 3-year follow-up, despite the inclusion requirement that women desire uterine conservation but not future childbearing.

We have followed reproductive outcomes in women after RFVTA of symptomatic fibroids in other studies as well. In our most recent analysis, presented in November at the 2015 American Association of Gynecologic Laparoscopists Global Congress, we identified 10 pregnancies among participants of the five prospective trials.

Of 232 women enrolled in premarket RFVTA studies – trials in which completing childbearing and continuing contraception were requirements – six conceived at 3.5-15 months post ablation. The number of myomas treated ranged from one to seven and included multiple types and dimensions. Five of these six women delivered full-term healthy babies – one by vaginal delivery and four by cesarean section. The sixth patient had a spontaneous abortion in the first trimester.

Of 43 women who participated in two randomized clinical trials undertaken after FDA clearance, four conceived at 4-23.5 months post ablation. Three of these women had uneventful, full-term pregnancies with vaginal births. The fourth had a cesarean section at 38 weeks.

Considering the theoretical advantages of the Acessa procedure – that it is less damaging to healthy myometrium – and the outcomes reported thus far, it appears likely that Acessa will be preferable to myomectomy. Early results from an ongoing 5-year German study that randomized 50 women to RFVTA or laparoscopic myomectomy show that RFVTA resulted in the treatment of more fibroids and involved a significantly shorter hospital stay and post-operative recovery ( Int J Gynaecol Obstet. 2014 Jun;125[3]:261-5 ).

The technique

The patient is pretreated with a nonsteroidal anti-inflammatory agent and prophylactic antibiotic. She is placed in a supine position with arms tucked, and a single-toothed tenaculum is placed on the cervix from 12 to 6 o’clock, without any instrument for manipulation of the uterus. The system’s dispersive electrode pads are placed symmetrically just above the patella on the anterior thighs; asymmetrical placement could potentially increase the risk of a pad burn.

Two standard laparoscopic ports are placed. A 5-mm trocar for the camera and video laparoscope is placed through the umbilicus or at a supraumbilical or left upper–quadrant level, depending on the patient’s anatomy, her surgical history, and the size of the uterus. A thorough visual inspection of the abdomen should be performed to look for unsuspected findings.

A 10-mm trocar is then placed at the level of the top of the fundus for the intra-abdominal ultrasound probe. Laparoscopic ultrasound is used to survey the entire uterus, map the fibroids, and plan an approach. Once the fibroid to be treated first is identified, the ability to stabilize the uterus accordingly is assessed, and the dimensions of the fibroid are taken. The dimensions will be used by the surgeon with a volume algorithm to calculate the length of ablation time based on the size of the fibroid and electrode deployment.

Under ultrasound guidance, the Acessa radiofrequency ablation handpiece is inserted percutaneously at 12, 3, 6, or 9 o’clock relative to the ultrasound trocar, based on the location of the target fibroid. The uterus must be stabilized, with the handpiece and ultrasound probe parallel and in plane. The handpiece is then inserted 1 cm into the target fibroid through the uterine serosal surface, utilizing a combination of laparoscopic and ultrasound views. Care must be taken to use gentle rotation and minimal downward pressure as the tip of the handpiece is quite sharp.

The location of the tip is confirmed by laparoscopic ultrasound, and the 7-needle electrode array can then be deployed to the ablation site. All three dimensions of the fibroid should be viewed for placement and deployment of the electrodes. Care is taken to avoid large blood vessels and ensure that the electrodes are confined within the fibroid and within the uterus.

Radiofrequency ablation is carried out with a low-voltage, high-frequency alternating current. The radiofrequency waves heat the tissue to an average temperature of 95° C for a length of time determined by a treatment algorithm. The wattage automatically adjusts to maintain the treatment temperature for the calculated duration of ablation.

Small fibroids can be treated in a manual mode without deployment of the electrode array at a current output of 15 W.

At the conclusion of the ablation, the electrodes are withdrawn into the handpiece, the generator is changed to coagulation mode, and the handpiece is slowly withdrawn under ultrasound visualization. The tract is simultaneously coagulated. A bit of additional coagulation is facilitated by pausing at the serosal surface.

Additional fibroids can be ablated through another insertion of the handpiece, either through the same tract or through a new tract.

Larger fibroids may require multiple ablations. The maximum size of ablation is about 5 cm, so it is important to plan the treatment of larger fibroids. This can be accomplished by carefully scanning large fibroids and visualizing the number of overlapping ablations needed to treat the entire volume. I ask my assistant to record the size and location of each ablation; I find this helpful both for organizing the treatment of large fibroids and for dictating the operative report.

It is important to appreciate that treatment of one area can make it difficult to visualize nearby fibroids with ultrasound. The effect dissipates in about 30-45 minutes. It is one reason why having a fibroid map prior to treatment is so important.

Once all fibroids are treated, a final inspection is performed. We usually use a suction irrigator to clean out whatever small amounts of blood are present, and the laparoscopic and port sites are closed in standard fashion.

Patients are seen 1 week postoperatively and are instructed to call in cases of pain, fever, bleeding, or chills. Most patients require only NSAIDs for pain relief and return to work in 2-7 days.

Many patients experience a slightly heavier than normal first menses after treatment. Pelvic rest is recommended for 3 weeks as a precaution, and avoidance of intrauterine procedures is advised because the uterus will be soft and thus may be easily perforated. Patients who have had type 1, type 2, or type 2-5 fibroids ablated may experience drainage for several weeks as the fibroid tissue is reabsorbed.

Dr. Berman is interim chairman of Wayne State University’s department of obstetrics and gynecology and interim specialist-in-chief for obstetrics and gynecology at the Detroit Medical Center. He was a principal investigator of the 3-year outcome study of Acessa sponsored by Halt Medical. He is a consultant for Halt Medical and directs physician training in the use of Acessa.

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