Effects of Shielded or Unshielded Laser and Electrohydraulic Lithotripsy on Rabbit Bladder

Abstract

The pulsed dye laser and electrohydraulic lithotriptor (EHL) are both effective devices for fragmenting urinary and biliary calculi. Both fragment stones by producing a plasma-mediated shockwave. Recently, a plasma shield consisting of a hollow spring and a metal end cap has been described for use with the laser and EHL devices in an attempt to minimize tissue damage without adversely affecting stone fragmentation rates. The tissue effects produced by a pulsed dye laser and an EHL device with and without plasma shields were examined and compared using rabbit urinary bladders. If blood was present, the unshielded laser perforated the bladder wall in two pulses. However, in the absence of blood, over 100 pulses were needed for the laser to perforate the bladder. A mean of six pulses were required to perforate the bladder wall with a shielded laser. The unshielded EHL perforated the bladder wall in two pulses, whereas, the shielded EHL required a mean of 35 pulses. Microscopically, areas of exposure revealed hemorrhage and tissue ablation. We conclude that all devices examined can produce significant tissue damage when discharged directly onto bladder epithelium.

A randomized trial comparing lithoclast with an electrokinetic lithotripter in the management of ureteric stones

“…The limitations of the ultrasound device include its inability to fragment hard stones composed of calcium oxalate monohydrate and dif®culty in miniaturizing the probe [7,8]. The EHL is a powerful lithotripter that has a high incidence of ureteric injury and the narrowest of safety margins [9,10]. In 1986 Watson and Wickham reported the use of the pulsed dye laser to fragment ureteric stones [11].…”

Intrahepatic Stones: The Percutaneous Approach

“…According to several Eastern and Western trials, percutaneous cholangioscopic electrohydraulic lithotripsy and laser lithotripsy seem to be comparably effective, with success rates of 81% to 100% (5,(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(28)(29)(30)(31). The largest series were reported from Asian countries because of the high incidence of hepatolithiasis.…”

“…The frequency and the intensity of the shockwave generation can be adjusted depending on the size and composition of the stones. Although EHL probes with built-in balloon catheters for positioning in the central axis of the bile duct are available, cholangioscopic control of shockwave application is strongly recommended because damage of the ductal wall may occur when the ductal wall comes in direct contact with the probe (13)(14)(15)(16)(17)(18)(19)(20)(21). Laser lithotripsy: Several systems for biliary laser lithotripsy have recently been reported in animal and clinical studies.…”

“…Laser lithotripsy: Several systems for biliary laser lithotripsy have recently been reported in animal and clinical studies. A flash-lamp, pulsed dye laser with a wavelength of 504 nm (Candela Company, Wayland, Massachusettes) has been used most frequently (21)(22)(23)(24)(25)(26)(27). The laser energy is transmitted via a 200 µm or 320 µm flexible quartz fibre.…”

“…A fluid medium is required for initiation of a laser plasma leading to stone fragmentation. Although conventional laser lithotripsy is probably safer than EHL, direct visual control is recommended because bile duct perforation may occur when the energy is inadvertently applied to the ductal wall (21,27). Intracorporeal cholangioscopic lithotripsy may be further improved by use of a new 'smart' laser with an automatic stone recognition system.…”