This video will review the equipment and technique for cryoablation of Barrett's esophagus with high grade dysplasia, including set-up, priming the catheter, placing the decompression tube, and performing cryoablation.
Prior to the procedure, the cryoablation unit is filled with liquid nitrogen. The unit itself has an indicator panel which displays the cryotherapy duration, as well as passive and active suction used to rapidly remove excess nitrogen gas from the stomach during treatment.
The liquid nitrogen spray is delivered through a special catheter designed to withstand freezing temperatures. When primed, liquid nitrogen gas is rapidly released from the catheter tip.
After equipment set-up, the next step is to examine the esophagus to delineate the extent of the Barrett's, as seen here under white light, and plan which areas will be targeted during treatment.
Next, a spring-tipped guidewire is placed in the stomach for placement of a decompression tube, and the endoscope is removed.
This tube allows the rapid removal of excess nitrogen gas during the procedure, preventing over-distension of the stomach and GI tract.
Next, a cap is placed on the endoscope to facilitate visualization during the procedure, the scope is reinserted next to the decompression tube, and the position of the decompression tube is confirmed. There is a black mark on the distal end of the tube, seen here, that must be identified and placed at the GEJ to ensure adequate gastric decompression.
When this is secure, a spring introducer is placed into the endoscope cap, and the catheter is inserted through the instrument channel and visualized at the end of the scope, positioned just past the edge of the cap. Of note, at this point the air/water button is no longer used to avoid water in the system that can freeze and obscure visibility.
The first area of Barrett's to be treated is then identified. Typically, an area 2-3 cm in length spanning approximately 1/3 of the esophageal circumference can be covered in one round of cryotherapy. The suction is then activated, and the cryospray is turned on.
Moving slowly in a distal to proximal fashion, the spray is applied until freezing, as evidenced by the mucosa turning white and frosty. Then the entire targeted area is frozen using slow to and fro movements. After a hard-freeze is achieved, the cryospray is applied for 20 additional seconds.
After the area thaws, which may take anywhere from 30 seconds to 2 or 3 minutes, a second round of cryotherapy is applied in the same area. Typically, the time to achieve a hard freeze is shorter for each subsequent application.
Then, the next area targeted for therapy is chosen, and the process is repeated.
At the end of the procedure, successful therapy results in an erythematous and friable esophageal mucosa. Patients are discharged with analgesics and anti-emetics to be taken on an as-needed basis, and a follow-up procedure is scheduled in 2 months time.
Evan S. Dellon, MD, MPH, University of North Carolina
Nicholas J. Shaheen, MD, MPH, University of North Carolina