Right Kidney Stone

I am 55 years of age, male. I had my first kidney stone almost 20 years ago. I went to the hospital and underwent unsuccessful uretroscopy to retrieve the stone by a urologist. Eventually I passed the stone on my own. Since I have had kidney stone episodes every 2 to 3 years. My recent right kidney stone is 4mm in size. I was unable to pass it. I went to the hospital again and a oncall urologist attempted unsuccessful laser lithotripsy. The urologist told me there was significant scar tissue all over (distal, middle and proximal ureter), he lasered some of the stricture at distal and middle ureter area to break the scar and ended up perforating my ureter. He then placed a stent and pushed the stone back in the kidney. He said the scar tissue is from prior instrumentation of the ureter. Now almost 3 months later I went to a highly recognized urologist, who tried to perform the laser lithotripsy again. The urologist abandoned the procedure as the ureter was significantly narrow and floppy, said did not want to damage it further or cause another perforation. Now the urologist is recommending either percutaneous removal of the stone or by extracorporeal lithotripsy. I don't want to damage my ureter permanently. Can anyone make any suggestions to dissolve this 4mm stone and how to prevent future stones. Thank you

Ranvir