| Summary: | Currently more than 90% of all common bile duct concrements
can he removed via the endoscopic retrograde route by means of endoscopic
papillotomy, stone extraction by baskets and balloon catheters, or mechanical
lithotripsy. Oversized, very hard or impacted stones however often st ill resist
conventional endoscopic therapy. Laser lithotripsy represents a promising new
endoscopic approach to the nonsurgical treatment of those common bile duct
stones. Currently only short-pulsed laser systems with high power peaks but low
potential for thermal tissue damage are used for stone fragmentation. Systems in
clinical applications are the pulsed free-running-mode neodymium YAG
(Nd:YAG) laser (1064 nm, 2 ms) and the dye laser (504 nm, 1 to 1.5 μs). Energy
transmission via highly flexible 200 ìm quartz fibres allows an endoscopic
retrograde approach to the stone via conventional duodenoscope or mother-baby-scope systems. New systems currently in preclinical and first clinical testing
are the Q-switched Nd:YAG laser (1064 nm, 20 ns) and the Alexandrite laser
(700 to 815 nm, 30 to 500 ns). By means of extremely short nanosecond pulses
(10-9 s) for the induction of local shock waves at the stone surface, possible tissue
damage is even more reduced. No complications have been reported so far after
applying laser lithotripsy clinically in about 120 patients worldwide. Compared
to extracorporeal shock wave treatment, laser lithotripsy can be executed in any
endoscopy unit in the scope of the endoscopic pretreatment and does not require
general anesthesia, which is often necessary for extracorporeal shock wave
lithotripsy.
|
|---|
