Esophageal Cancer. Part 2
What about rigid prostheses? Those of you who have passed a couple of the Celestin type or other rigid type tubes probably get a visceral response just looking at this slide. It’s a fairly uncomfortable procedure both for the endoscopist as well as the patient, but basically this is where a rigid plastic tube is shoved through the distal tumor with the use of a pusher-tube device. What’s the problem with this technique? Well, technically it’s difficult to perform. These tubes are big. The outside lumen is about 18, the outside of the diameter of the tube is typically 16-18 mm in size, so it requires fairly aggressive either single or serial dilatation maneuvers in order to allow the tube to be eventually advanced. Frequently general anesthesia is necessary for the patient to tolerate this procedure. Again, when you are pushing fairly vigorously with this device, or with the dilation maneuvers, perforation is a concern. Looking at all series, it averages about 10%. These are not small perforations. These are usually the big rips. The mortality per procedure, across the board for placing this type of tube, is about 2-4%. So it’s quite significant. Once these tubes are in position they don’t always stay there. The migration rate averages between 20-40%. They can pop proximally or distally as well. So again, migration and perforation, significant problems.
Laser photoablation is ideal for an exophytic, non-circumferential type of tumor. Again that fleshy type of tumor. And with a couple of laser sessions you can see that the tumor melts away, and with further efforts you can see the laser being fired. This is again with the YAG laser. You can create a pretty significant lumen. What are the downsides? Obviously it is expensive technology. It typically takes a couple of sessions at least to get the patient to this point where the lumen is a relatively decent patent size, and also downstream the tumors come back, the patients have to return. On average, patients who have laser photoablation therapy as their only endoscopic therapy average 4-5 endoscopic therapies during their remaining lifetime. So that’s one of the downsides as well.
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The new kids on the block are the self expanding metal stents. Brent showed us a picture earlier of their use in the biliary tract. They were first modified for esophageal use about 1991. This is an example of the Schneider Wallstent in place. The advantage of this type of device – obviously those of you who place it are quite aware of this – but it can be mounted onto a delivery catheter where it’s held in check with a sheath. When the sheath is withdrawn the stent is deployed, and then it provides a force against this esophageal tumor, hopefully providing a nice lumen such as seen here where the lumen is about 18 mm. There are now currently four commercially made stent devices. This is an example of the EsophaCoil, made by Medtronic. This is a nitinol device, nitinol alloy which is a combination of nickel and titanium. It is kind of a flat ribbon which has a nice memory feature, so the stent kind of recoils back to its original position after deployment. It has excellent radial force. It’s a nice stent to use in the distal esophagus, for example, when extrinsic compression is a concern. Once deployed, the coils are supposed to slide nicely and snug together hoping to prevent ingrowth of tumor. This is the Ultraflex device, both in the uncovered and covered. Again, a nitinol-type of compound metal. It has a very soft flexible feel to it so it’s a handy stent to use when there is a sharply angulated stricture. This is the Schneider Wallstent. The version on the right is the Wallstent I, which has a good radial force but the trouble was it was packaged into a 38 French catheter. Fairly stiff delivery system, which then allowed this stent to be deployed. Schneider has subsequently made the Wallstent II version which still provides a good lumen size, 18-19 mm lumen size, but this device is now packaged onto a 6 mm diameter catheter. So a very thin flexible catheter that can be placed much more easily and without the usual pre-dilation maneuvers compared to the old Wallstent version.