High-intensity focused ultrasound for fibroid devascularization

A Chinese study published in Ultrasound in Medicine & Biology used ultrasound color Doppler flow imaging (CDFI) and B-mode imaging to target fibroid vascularity.¹

The study enrolled 42 patients from International Peace Maternity and Child Health Hospital in Shanghai, China between January 2019 and May 2020.

The patients, with a median age of 41.24 years, each had only 1 fibroid treated. The median fibroid volume was 66.98 cm3, ranging from 10.44 cm3 to 173.81 cm3.

Among the 42 treated fibroids, 24 were anterior fibroids, 5 were posterior fibroids, 9 were lateral fibroids, and 4 were fundus fibroids.

The median thickness of the abdominal wall, including skin and fat, was 2.32 cm, ranging from 1.40 cm to 4.00 cm.

The treatment procedure for fibroid devascularization consisted of 4 steps: targeting, arrangement of treatment cells, sonication, and intraoperative assessment.

The vessels were covered and ablated by high-intensity focused ultrasound (HIFU) spots.

“After the generation of the treatment cells, sonication was started from the deepest treatment cell, and the treatment cell was moved through movement of the treatment bed,” wrote the authors. “The focal spots were steered inside the treatment cell by adjusting the amplitude and phase of the signal fed to each element.”

Neither anesthesia nor sedation were used before, during, or after treatment. Intraoperative pain was mild and transient; patients felt pain only when the sonication was on.

No blood flow was detected by post-treatment CDFI in 40 of the fibroids, for which the 6-month nonperfusion volume rate was 75.23%.

Overall, the mean shrinkage in fibroid volume was 38.20% and 43.89%, respectively, at 1 and 6 months after treatment (P < 0.001).

In addition, uterine fibroid symptoms and quality of life scores were reduced by 9.43% at 1 month and by 26.66% at 6 months after treatment (P < 0.001).

Of the 42 patients, 38 successfully completed treatment. One of the 4 patients whose treatment was stopped was due to painful paresthesia in the lower limb. Treatment for the other 3 patients was ceased by the physician because blood flow could be still detected in the fibroids after a lengthy treatment session of over 2 hours.

All 4 patient underwent a repeat session 1 week later.

Compared to other minimally invasive methods like radiofrequency (RF) ablation and uterine artery embolization (UAE), HIFU has a lower incidence rate of vascular adverse events and associated complications, according to the authors.

No serious adverse events were observed for any study patient. The most common adverse event was a mild degree of pelvic pain in 11 patients; 3 patients also experienced abnormal vaginal discharge and another patient with lumbar disk herniation had lower limb paresthesia, unable to lie horizontally for the required roughly 2 hours.

All 15 patients with adverse events recovered within 1 week and none required additional treatment or medication during the recovering period.

“USgHIFU-induced devascularization has the potential to become a useful tool for gynecologists and obstetricians,” wrote the authors, noting that the treatment outcome of their study is similar to previous studies; however, more studies are needed to evaluate the safety and efficacy of the procedure.

__

Reference

Zhou Y, Ji X, Niu J, et al. Ultrasound-guided high-intensity focused ultrasound for devascularization of uterine fibroid: a feasibility study. Ultrasound Med Biol. Volume 47, Issue 9, September 2021, pages 2622-2635, doi:org/10.1016/j.ultrasmedbio.2021,05.012