Focused ultrasound ablation of the epididymis with use of thermal measurements in a canine model

Nathaniel M. Fried, William W. Roberts, Yegor D. Sinelnikov, E. James Wright, Stephen B. Solomon

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


Objective: To explore the epididymis as an alternative anatomical target to the vas deferens for noninvasive male sterilization using therapeutic focused ultrasound.Design: Controlled preclinical study. Setting: Canine animal model in an academic research environment. Patient(s): Four healthy male mongrel dogs (30-35 kg). Intervention(s): A transducer mounted on a plastic clip delivered ultrasound energy to the canine epididymis. Thermocouples placed transcutaneously into the epididymis, intradermally, and on the skin surface recorded temperatures during ablation with a wide range of acoustic powers and sonication times (control, 3 W/120 s, 5 W/90 s, 7 W/60 s). Main Outcome Measure(s): Thermocouple temperature measurements determined the optimal range of ablation parameters that produced successful thermal occlusion of the epididymis without adverse effects (e.g., skin burns, testicular injury). Result(s): A large 'therapeutic window' was determined (power = 3-7 W, time = 20-120 seconds) over which noninvasive thermal occlusion of the epididymis can be achieved. Thermal occlusion rates were higher, and complications lower, than found previously with vas deferens ablation. Conclusion(s): The epididymis represents a larger and easier target than the vas deferens for performing noninvasive male sterilization using focused ultrasound. Long-term azoospermia studies will be necessary to confirm permanent sterilization with this technique.

Original languageEnglish (US)
Pages (from-to)609-613
Number of pages5
JournalFertility and sterility
Issue number3
StatePublished - Sep 2002


  • Epididymis
  • HIFU
  • Noninvasive
  • Skin burns
  • Sterilization
  • Temperature
  • Ultrasound
  • Vasectomy

ASJC Scopus subject areas

  • Reproductive Medicine
  • Obstetrics and Gynecology


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