Laser lithotripsy for pancreatic duct stones

Abstract

Aim. To confirm the possibility of minimally-invasive laser procedure for fragmentation of stones in the pancreatic duct following the results of laboratory experiments and medical practice. Materials and methods. A fully functional hardware complex consisting of a pulsed laser unit, video endoscopic system and cooling system was created for experimental stone fragmentation in laboratory. The experiments involved microscopic video registration of the fragmentation process, pressure and temperature measurement in the stone area. Pancreatic stones, human and artificial gallstones as well as porcine pancreas were used in the experiments; the gastrointestinal tract was made of silicone, the pancreas was made of gelatin aqueous solution jelly. In clinical practice, a patient with lithiasis of Wirsung's duct was assigned to ultrasound and CT, then endoscopic papillosphincterotomy, endoscopic pancreatoscopy, laser lithotripsy and lithoextraction, pancreatic duct stenting. The procedures involved a laser unit, videoduodenoscope, catheter and their video systems. Results. The laboratory experiments established that effective and safe laser fragmentation of stones from 4 × 7 mm into 0.1–2 mm occurs in the flowing fluid in front of the stone at 1 μs laser pulse duration, 5–15 Hz frequency and 120–150 mJ laser energy. After laser fragmentation of the stone in a patient with virsungolithiasis and removal of fragments from the duct, the patient was discharged from the hospital on the 12th day due to improvement of healthcondition. Conclusion. The possibility of minimally-invasive fragmentation of stones in the pancreatic duct by laser lithotripsy has been proved.