Endometrial ablation is a procedure used by gynecologists to treat non-malignant abnormalities of uterine or menstrual bleeding that are symptomatic because of prolonged length, excessive volume, or both. Various ablation techniques are available to the clinician but, in each, energy is delivered to the endometrium (uterine lining) to ablate it such that the native endometrium is replaced by tissue unresponsive to hormone cycles and thus less likely to shed and bleed. The procedure has been offered in different forms since the 1980s as an alternative to hysterectomy to treat abnormal uterine bleeding, and it can be up to 80% effective in resolving symptomatic bleeding. Originally performed via hysteroscopy exclusively, endometrial ablation has evolved into a procedure that can be performed in the physician’s office using sedation and local anesthetic. The technique can involve hysteroscopy, along with application of radiofrequency energy, extreme heat in the form of heated saline, microwave energy, or extreme cold (to -20°C). Cryoablation represents the last of those.
Endometrial ablation has demonstrated feasibility as an office procedure. Because the procedure involves the application of doses of energy lethal to uterine tissue, patient selection, adequate anesthesia, and technical skill and knowledge of the particular technology used are all crucial to the safety of the procedure.
“Global” endometrial (cryo)ablation using pressurized gas coolants delivered to a probe deployed inside the uterus is used to achieve a temperature of -20°C, which is lethal to tissue. The gas in the probe creates a “CryoZone” or “ice ball” which grows with time and, at six minutes, is approximately 3.0 by 5.8 cm. The ice front advances through the uterine issue rather than expanding within the endometrial cavity, and therefore must be observed continuously by ultrasound to ensure that it does not get too close to the serosa or outside of the uterine wall, lest it directly or indirectly injure adjacent tissues such as bowel. It is for this particular safety concern that there are several contraindications to the use of cryoablation according to the manufacturers, including any anatomic or pathologic condition in which weakness of the myometrium could exist, such as history of previous classical cesarean sections or transmural myomectomy.
Safety in avoiding injuries related to perforation with direct injury to pelvic viscera including bowel, or indirect injury to adjacent pelvic viscera including bowel requires vigilant ultrasonic visualization during the ENTIRE procedure.
Endometrial cryoablation medical expert witness specialties include gynecology, robotic gynecologic, surgery, and anesthesiology.