Transvaginal artificial ascites infusion as a spacer in gynecological brachytherapy: a novel technique

Abstract

This is a first paper to report on artificial ascites infusion via vaginal wall for pelvic interstitial brachytherapy. Artificial ascites is commonly used for treating liver tumors, with radiofrequency ablation and percutaneous artificial ascites infusion through the abdominal wall for pelvic brachytherapy has been previously reported by our group. However, the trans-abdominal needle approach under ultrasound guidance is unreliable due to poor visualization resulting in fluid injection into the abdominal wall or mesenterium and the rate of successful artificial ascites infusion was low. Target tumor of the vaginal cuff brachytherapy is usually adjacent to the intestine, and transvaginal artificial ascites infusion under trans-rectal ultrasonography is considered as a rational and simpler method to create a space between target volume and organs at risk, such as intestines or sigmoid colon, by increased visualization of the needle compared to trans-abdominal approach. Here, we report a practical experience of transvaginal artificial ascites infusion.

MucoUp® as a spacer in brachytherapy for uterine cervical cancer: A first-in-human experience

“…However, when the needle is inserted into the peritoneal cavity, the spacer material dissolves in the peritoneum, and a meaningful space cannot be obtained only with 20–40 ml of hydrogel. In such a case, artificial ascites injection can be used to create a space higher than the peritoneal reflection [25] .…”

Hydrogel spacer injection to the meso-sigmoid to protect the sigmoid colon in cervical cancer brachytherapy: A technical report

“…While the use of solid spacers, such as mesh or polyglycolic acid spacers (Neskeep ® , Alfresa Pharma Corporation, Osaka, Japan) [12][13][14][15] between tumor and sigmoid colon can be beneficial, this method requires open abdominal surgery, and is much more invasive. Another technique involves trans-vaginally injected artificial ascites into the peritoneal cavity to float the sigmoid colon and create separation from tumor [1,2]. Nevertheless, the effectiveness of artificial ascites varies among patients due to increased fluid absorption within the peritoneal cavity in a short time, supposedly because of peritoneal inflammation.…”

“…However, in cases where the sigmoid colon is proximal to the uterine cervix, radiation exposure to the sigmoid from HDR-ISBT can be high. In such circumstances, artificial ascites injection, a treatment choice we previously proposed [ 1 , 2 ], could be used to float the sigmoid colon and maintain a distance from gross tumor volume (GTV) to the sigmoid colon. However, in some patients, the fluid is re-distributed within the peritoneal cavity in a short time, and therefore, despite injecting saline into peritoneal cavity, the liquid soon disappears.…”

Technical Note: High-Dose-Rate Interstitial Brachytherapy for Pelvic Sidewall Recurrence Using Intraperitoneal Spacers

“…This strategy, although it requires surgery, is theoretically reliable and has the advantage of reproducibility in creating the distance between the recurrent tumor and the sigmoid colon at each brachytherapy session. Artificial ascites 8 , 9 and hyaluronic acid gel injected into the vesicovaginal and rectovaginal spaces 10 , 11 , 12 , 13 , 14 are also used as other means of dose reduction for OARs in pelvic brachytherapy. However, these methods cannot ensure reproducibility for each treatment due to inconsistent injection volume and position, as well as the volume of artificial ascites changing over time because of absorption.…”