Now, every time we look at the subject there are some pros and cons and there are some number differences in the success. This is the shock wave lithotripters, every investigator used different way. This is our Medstone lithotripsy, US trial, which I will go a little bit more into. Some of them use piezoelectric, electrohydraulic, and electromagnetic. You can use the years of the studies done, number of the patients, and stone-free gallbladder percentage-wise after 6 months to 12 months. 6 months altogether possibly around 65 to 70%, even might go down to 47%, and after 12 months this might go up to 80.
Now, let me focus this 51% a little bit and a little bit of history on that. I was one of the investigators. I was a little younger at that time and I was pretty enthusiastic. I stayed with my patient and I really did every patient personally along with my other collaborators. Radiologist was together with us, later on radiology technician. I will show my results. From my single center we had results up to 90% stone free gallbladder (with single stone). But some other centers, the number was around 30%, even 28% at one center. So what happened when you put all that center experience together, is some of the centers have only three patients, some centers have around 40 patients at a given time in the study. We had one more than 50 patients. So when you put all this together this comes to 51%. I was in the FDA panel and the FDA told us, all right, this doesn't look very promising, all the numbers are little, all numbers are small. Your results are not very attractive. Do more studies and we might approve this thing. Now, the FDA approved this thing because some of the Americans went to Europe, most likely for that reason (might be minor reason) to have this non surgical modality in Germany or France and even in Canada. There is one center in Canada leading the centers. If it's done casually, as shown in my study published in Gastroenterology in 1992, with the same machine you're going to use, if you have a single stone, again, if you really select the patient properly, if you stay with the patient, locate the F2 point properly, your patient might leave the table after the procedure around 59% stone-free. This is a pretty impressive number. And after 6 months this number goes to 75%, and after 12 months 89 to 90% for single stones. But if you have multiple stones as shown in yellow bars, stone-free gallbladder immediately after procedure is 33%; later on it's 50%, doesn't go up to more than 65%. But overall if you put all the patients with stones, multiple or single stones, overall success rate at the end of the trial months was 77% in our hand at that time with the same machine.